Skip to main content
PMC home page
Springer logoLink to Springer
. 2019 Jun 15;145(8):2083–2095. doi: 10.1007/s00432-019-02946-8

Human cytomegalovirus infection is correlated with enhanced cyclooxygenase-2 and 5-lipoxygenase protein expression in breast cancer

Helena Costa 1,2, Joel Touma 1,2,3, Belghis Davoudi 1,2, Melinda Benard 4,5, Torill Sauer 6,7, Jürgen Geisler 6,8, Katja Vetvik 3,6, Afsar Rahbar 1,2,✉, Cecilia Söderberg-Naucler 1,2,✉
PMCID: PMC6658585  PMID: 31203442

Abstract

Purpose

While enhanced expression of cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LO) and their derived metabolites is associated with breast cancer (BC) risk, the precise link between BC carcinogenesis and enhanced inflammatory activity remains to be clarified. Human Cytomegalovirus (HCMV) may induce expression of COX-2 and 5-LO and is frequently found in breast cancer biopsies. Thus, we investigated whether there is an association between HCMV proteins and expression of COX-2 and 5-LO in human BC tissue and BC cell lines.

Materials and methods

Paraffin embedded biopsies obtained from 49 patients with breast cancer and 26 tissue samples from adjacent, benign breast tissues were retrospectively examined for HCMV-immediate early (IE), HCMV-Late (LA), COX-2, and 5-LO proteins by immunohistochemistry. In vitro, uninfected and HCMV-infected BC cell lines were examined for COX-2 and 5-LO transcripts and proteins by PCR and flow cytometry.

Results

Extensive expression of COX-2, 5-LO and HCMV-IE proteins were preferentially detected in BC samples. We found a statistically significant concordant correlation between extensive HCMV-IE and COX-2 (P < 0.0001) as well as with HCMV-IE and 5-LO (P = 0.0003) in infiltrating BC. In vitro, HCMV infection induced COX-2 and 5-LO transcripts and COX-2 proteins in MCF-7 cells (P =0.008, P =0.018, respectively). In MDA-MB-231 cells that already had high base line levels of COX-2 expression, HCMV induced both COX-2 and 5-LO proteins but not transcripts.

Conclusion

Our findings demonstrate a significant correlation between extensive HCMV-IE protein expression and overexpression of COX-2 and 5-LO in human breast cancer.

Electronic supplementary material

The online version of this article (10.1007/s00432-019-02946-8) contains supplementary material, which is available to authorized users.

Keywords: Human cytomegalovirus, Breast cancer, 5-LO, COX-2, MCF-7, MDA-MB-231

Introduction

Breast cancer (BC) is the most common cancer in women worldwide and although implementation of novel therapies and early detection has improved quality of life and decreased mortality rates for some BC subtypes, the overall incidence of BC continues to increase (Jemal et al. 2011). Of high concern, the overall survival has not improved significantly albeit new therapies for patients with metastatic BC have been introduced during the past decades (https://www.kreftregisteret.no/globalassets/publikasjoner-og-rapporter/cancer-in-norway/cancer_in_norway_2009.pdf), suggesting that alternative treatment options are urgently needed. Somatic mutations in breast cancer-associated genes are today considered to be one of the main causes and drivers of BC. In addition, epigenetic and genetic alterations in key breast cancer genes such as BRCA-1/2 and their downstream regulation of DNA repair mechanisms, or in genes with impact on epithelial cell proliferation, differentiation and migration are suggested to promote breast cancer carcinogenesis (Petrucelli et al. 1993). Emerging evidence also highlights a role of the tumor microenvironment to induce pre-malignancies and promote tumor progression. Stroma cells like specialized mesenchymal cells and myo-fibroblasts, endothelial cells and infiltrating leukocytes with capacity to produce inflammatory factors may promote breast cancer carcinogenesis and affect tumor progression and metastasis formation (Balkwill et al. 2005; Coussens and Werb 2002; de Visser et al. 2006). Inflammatory cells present in the tumor microenvironment support tumor growth and enhanced malignancy, by releasing cytokines, chemokines and growth factors. Their increased production of reactive oxygen species also further enhance inflammation, oxidative DNA damage and impair DNA repair mechanisms (Coussens and Werb 2002). Therefore, chronic inflammation is considered a risk factor for breast cancer development, and added inflammation to their revised version of the Hallmarks of Cancer (Hanahan and Winberg 2011).

Eicosanoids are potent inflammatory mediators that are produced from arachidonic acid by cyclooxygenases (COXs) and lipoxygenase (LO). Enhanced inflammation via COX-2 and 5-LO promotes tumorigenesis (Chen and Smyth 2011) and is associated with poor prognosis of several cancer forms (Dreyling et al. 1986; Hennig et al. 2002; Steele et al. 1999). Over-expression of COX-2 was observed in 40% of patients with invasive breast carcinoma and correlated with poor prognosis (Denkert et al. 2003; Howe 2007). Selective COX-2 inhibitors reduce the risk of breast cancer, suppress breast cancer cell migration and invasion, and exhibit strong anti-neoplastic effects in animal models (Wang and DuBois 2010; Harris et al. 2006, 2014). COX-2 inhibitors are, therefore, currently evaluated as potential new cancer therapies, especially in epithelial-derived malignancies. A randomised phase II study of 111 postmenopausal women with advanced breast cancer indicated a trend towards a longer duration of clinical benefit in the combination arm (median, 96.6 weeks vs 49 weeks) compared to the exemestane monotherapy arm (Dirix et al. 2008). Inhibition of 5-LO activity in several breast cancer cell lines also resulted in growth inhibition and enhanced apoptosis, but 5-LO inhibitors have not yet been evaluated in clinical trials in breast cancer patients (Avis et al. 2001).

Human cytomegalovirus (HCMV) is a ubiquitous herpesvirus that is proposed to be highly prevalent in different cancer forms including breast (Harkins et al. 2010; Taher et al. 2013, 2014), colon (Dimberg et al. 2013; Harkins et al. 2002; Tafvizi and Fard 2014) and prostate cancer (Samanta et al. 2003), glioblastoma multiforme (Cobbs et al. 2002; Lucas et al. 2011; Rahbar et al. 2015), medulloblastoma (Baryawno et al. 2011) and neuroblastoma (Wolmer-Solberg et al. 2013). HCMV is also present in sentinel lymph node metastases of breast cancer and in brain metastases originating from breast and colon cancer, while healthy tissues surrounding HCMV positive primary tumors are generally HCMV negative. In breast cancer, HCMV was detected in 92% of primary tumors, in 94% of sentinel lymph nodes, and in 99% of brain metastases originating from breast cancer (Taher et al. 2013, 2014). These observations suggest a concerning association between HCMV and malignant cell growth. However, it remains to be clarified whether these findings represent an epiphenomenon or indicate that HCMV infections induce tumor-promoting mechanisms of relevance for local tumor progression.

A close link between HCMV infections and inflammation has been established in the literature. Thus, latent HCMV can be reactivated by inflammation and the virus further promotes inflammation by inducing expression of both COX-2 and 5-LO (Benard et al. 2014; Qiu et al. 2008; Hooks et al. 2006). Results from a mouse model based on virus-induced adenocarcinoma (Bongers et al. 2010), confirmed production of inflammatory factors such as IL-10, TGF-β, IL-1β, IL-8, IL-6, MIP-1α, MIP-1β, and RANTES (Bodaghi et al. 1998; Kotenko et al. 2000; Reeves et al. 2005; Söderberg-Nauclér et al. 1997) to be involved. We earlier showed that COX-2 is almost exclusively expressed by HCMV-infected cells in medulloblastoma and that COX-2 inhibition acts to inhibit HCMV, which led to decreased tumor growth in an animal model (Baryawno et al. 2011; Schroer and Shenk 2008). In addition to inducing inflammation, HCMV may directly modulate tumor cells by affecting intracellular pathways involved in cell cycle regulation, epigenetic regulation of gene expression, cellular invasion, angiogenesis, immune evasion, and apoptosis (Cinatl et al. 2004a, b; Slinger 2010; Vossen et al. 2002), all highly relevant in tumor biology.

The main objective of this study was to investigate a potential association between HCMV infection and simultaneous expression of COX-2 and 5-LO in BC. We examined the expression of HCMV proteins, COX-2 and 5-LO, in tissue samples obtained from BC and in adjacent normal breast tissues and investigated whether the activity level of HCMV was associated with inflammatory markers and impaired clinical outcome. In additional in vitro experiments, we assessed whether HCMV could affect the expression of 5-LO and COX-2 in well-established BC cell lines.

Materials and methods

Study design

Paraffin-embedded tissue specimens of infiltrating BC (n = 75) and adjacent normal breast tissue (n = 26) were retrospectively obtained from 49 patients who underwent surgery at Akershus University Hospital, Oslo, Norway during 2011. Clinical data (Table 1) were provided by the Departments of Oncology and Pathology at Akershus University Hospital (AHUS). All diagnoses were re-confirmed by an experienced BC pathologist (T.S.) at AHUS. The median age at surgery was 58.7 years. Most patients underwent mastectomy (61%), while 35% had breast-conserving surgery, and 4% bilateral surgery. All patients received standard adjuvant treatment according to the Norwegian guidelines approved at the time of surgery (Table 1); (http://www.nbcg.no).

Table 1.

Patients characteristic

n (%)
Patient characteristics
 Patients 49
 Median age (years) 49
 Median age at surgery (years) 58.7
Type of surgery
 Breast conserving 17 (35)
 Ablation 30 (61)
 Bilateral 2 (4)
Histology
 Infiltrating ductal cancer 41 (84)
 Infiltrating lobular cancer 4 (8)
 Medullar cancer 0 (0)
 Multiple cancer types 1 (2)
 Mucinous subtype 3 (6)
Grades (n = 48)
 I 6 (13)
 II 17 (35)
 III 25 (52)
T stadium (n = 49)
 T1 25 (51)
 T2 24 (49)
N stadium (n = 49)
 N0 29 (59.2)
 N1 11 (22.4)
 N2 7 (14.3)
 N3 2 (4.1)
ER expression
 Positive (≥ 1%) 35 (71)
 Negative 14 (29)
PGR expression
 Positive (≥ 10%) 23 (47)
 Negative 26 (53)
HER2 expression
 Positive (IHC3 + or FISH +) 8 (16)
 Negative 41 (84)
Ki-67 labeling index (n = 42)
 < 1% 1 (2.4)
 > 1–30% 22 (52.4)
 > 31–100% 19 (45.2)
Menopause (n = 18)
 Premenopause 5 (28)
 Postmenopause 13 (72)
Neoadjuvant treatment
 Yes 1 (2)
 No 48 (98)
Adjuvant chemotherapy
 No chemotherapy 19 (39)
 FEC60 × 6 2 (4)
 FEC60 × 4 followed by taxanes (every 3 weeks) 19 (39)
 FEC100 × 4 followed by taxanes (every 3 weeks) 9 (18)
Adjuvant endocrine treatment
 None 19 (38.8)
 Tamoxifen (5 years) 15 (30.6)
Aromatase inhibitor (5 years) 15 (30.6)
Adjuvant radiation
 No 17 (35)
 Yes 32 (65)
Adjuvant anti-HER2 treatment
 No 41 (84)
 Yes 8 (16)
Relapse
 No 45 (92)
 Yes 4 (8)
Loco regional relapse
 No 49 (100)
Distant metastasis
 No 44 (90)
 Yes 5 (10)
Type of distant metastasis (n = 5)
 Lymph nodes 2 (40)
 Brain 2 (40)
 Multiple metastasis 1 (20)
Alive
 Death 4 (8)
 Alive 45 (92)
Open in a new tab

T stadium tumor size and extension into neighboring breast tissue, N stadium lymph node involvement

Immunohistochemistry

Tissue microarrays were created, and all tissues were sectioned (4 µm) and analyzed by immunohistochemical techniques optimized in our laboratory. Detection of HCMV proteins was done as described previously with only minor modifications (Taher et al. 2013). Tissue specimens were deparaffinized in xylene (Sigma Aldrich), rehydrated in an ethanol (Apoteket Farmaci), and washed in Tris-buffered saline (TBS) containing Triton X-100 (Substrate Department, Karolinska University Hospital). Antigen retrieval and unmasking was done by heating the tissues in DIVA decloaker buffer (Histolab), pH 6.2, in a pressure cooker (BioCARE) for 15 min. Endogenous peroxidase activity was blocked with peroxidase 1 (Histolab) for 5 min, and nonspecific binding was blocked with Sniper (Histolab) for 16 min at room temperature. The tissue sections were then incubated with antibodies against HCMV-IE and HCMV-LA (IgG2a, Merck), COX-2 (CellSignaling), 5-LO (Abcam), and cytokeratins 5, 6, 8, 17, and 19 (IgG1, Dako). An antibody against cytokeratin 20 (IgG2a, Chemicon International) and rabbit IgG (Biocare Medical) served as negative controls. Paraffin-embedded tissue section from HCMV-infected placenta was used as positive control and from HCMV negative breast cancer patient as negative control for IHC.

During the staining procedure a few of the tissue sections were lost.

HCMV, COX-2, and 5-LO staining was evaluated as described previously (Taher et al. 2013), and according to the estimated percentage of cells expressing HCMV or COX-2 or 5-LO proteins: negative (0%), grade 1 (< 25%), grade 2 (≥ 25–50%), grade 3 (≥ 50–75%), and grade 4 (≥ 75%). To ensure a sufficient number of cases in each category for statistical analysis, tumors were considered as HCMV-negative or as having focal HCMV infection (< 50% positive cells) or extensive infection (≥ 50% positive cells). Immunohistochemical (IHC) staining for HCMV was evaluated and graded by a senior scientist (A.R.) without access to the clinical records at Karolinska Institutet, Stockholm, while IHC staining for Ki-67 was performed and evaluated at the Department of Pathology, Akershus University Hospital.

Cell lines and virus

Breast cancer cell lines MCF-7 (ER/PR/ positive but HER2 negative) and MDA-MB-231 (ER/PR/HER-2 negative), both from ATCC, were cultured in RPMI 1640 medium supplemented with 10% foetal bovine serum (FBS), 100 U/ml of penicillin and 100 µg/ml of streptomycin and maintained in a 37-C incubator with 5% CO2. Viral stocks of HCMV VR1814 strain were prepared through virus propagation in human umbilical vein endothelial cells (HUVEC) at low passage and ultracentrifugation of supernatants as described earlier (Frascaroli and Sinzger 2014).

RNA extraction and quantitative real-time PCR (qPCR)

MCF-7 and MDA-MB-231 cells were infected with HCMV VR1814 at multiplicity of infection (MOI) of 5 and were collected at different times post-infection. RNA was extracted from lysed cells using RNeasy Mini Kit (Qiagen) according to manufacturer’s instructions and cDNA was synthesized using random primers and the high-capacity cDNA reverse transcription kit (Applied Biosystems). Gene expression levels were quantified by real-time PCR using TaqMan Fast Universal PCR Master Mix (Life Technologies) and the following specific TaqMan probes: COX-2 (PTGS2, assay ID Hs00153133_m1), 5-LO (ALOX5, assay ID Hs00167536_m1), HCMV IE, and human β2-microglobulin (B2M, assay ID, Hs00984230_m1) (Life Technologies). The PCR was performed using a 7900HT Fast Real-Time PCR system (Applied Biosystems). The endogenous control B2M was used for normalization and relative expression was determined by the 2−ΔΔCt method. (Three separate experiments were performed).

Flow cytometric analysis (FACS)

MCF-7 and MDA-MB-231 cells non-infected or infected with HCMV MOI of 5 were fixed at 6 days post infection (dpi). Cells were treated in Fix &Perm Medium A and B according to the supplier`s instruction (Molecular Probes) and co-stained with primary antibodies HCMV IE (Merck) and COX-2 (CellSignaling) or 5-LO (Abcam) diluted in phosphate-buffered saline (PBS) containing 1% BSA (Sigma) for 45 min at 4 °C. After washing with PBS, cells were incubated with secondary Alexa Fluor 633 goat anti-mouse antibodies (Life Technologies) and Alexa Fluor 488 anti-rabbit antibodies (Invitrogen). Rabbit IgG (Biocare Medical) and mouse IgG2a (Dako) served as negative controls. Acquisition was performed using Flow cytometry (FACS) and data were analyzed by Summit 4.3 software. (Three separate experiments were performed).

Statistical analysis

All analyses were done with GraphPad Prism version 6; P < 0.05 was considered statistically significant. Nonparametric Pearson correlation assay was used to assess statistical significance of correlation between different grades of HCMV-IE, COX-2, and 5-LO in BC tissues. Two-tailed Student t test was used for analysis of in vitro data, presented as mean standard deviation.

Results

High prevalence of HCMV-IE, COX-2, and 5-LO proteins in BC, but not in adjacent non-malignant breast tissues

Expression of HCMV-IE, HCMV-LA, COX-2, and 5-LO proteins was analyzed in available tissue sections by immunohistochemistry. HCMV IE protein was detected at different levels in breast cancer (BC) tissue specimens from all 49 patients and HCMV-LA protein was found in 22% (11/49) of BC patients. HCMV IE protein expression was extensive (defined as > 50% positive cells) in 73% (55/75) of BC tissue specimens, but only in 8% (2/26) of adjacent breast tissue specimens (Figs. 1, 2, 3). This cohort of breast cancer patients was previously investigated for HCMV protein expression and association with estrogen receptor-alpha (ER) and progesterone receptor (PGR) expression and the results were reported earlier (Rahbar et al. 2017). Most of tumor specimens exhibited low expression of HCMV LA proteins; extensive HCMV-LA expression was only present in 3 of 75 (4%) of BC specimens, and in none of adjacent breast tissue specimens (Figs. 2, 3). COX-2 protein expression was extensive in 58% (48/67) of BC specimens and in 8% (2/26) of adjacent non-tumor breast specimens (Figs. 1, 2, 3). 5-LO protein expression was extensive in 53% (40/75) of BC specimens and in 31% (9/29) of adjacent non-tumor breast specimens (Figs. 1, 2, 3). Expression of HCMV-IE protein was detected in HCMV positive placenta tissue section, but not in HCMV negative breast tumor tissue section by immunohistochemistry (Supplemental Fig. 1A-B).

Fig. 1.

Fig. 1

Open in a new tab

Detection of HCMV-IE and HCMV-LA in infiltrated BC and adjacent normal breast tissue by immunohistochemical staining (IHC). Extensive HCMV-IE but not HCMV-LA was frequently detected in infiltrated BC (a). Extensive HCMV-IE and COX-2 were detected in majority of infiltrated BC (b, c)

Fig. 2.

Fig. 2

Open in a new tab

Concordant expression levels of HCMV-IE and COX2/5-LO in BC tissue specimens (a, b). Images show extensive expression of HCMV-IE, COX-2 and 5-LO in the same BC tissue specimens (a). Images show focal expression of HCMV-IE, COX-2 and 5-LO in the same BC tissue specimens (b). Lower panel present magnified images from upper panel. A significant correlation was detected between concordant expression levels of HCMV-IE, COX-2 and HCMV-IE, 5-LO (c, d)

Fig. 3.

Fig. 3

Open in a new tab

Correlation between concordant expression of HCMV-IE, COX-2 and 5-LO in adjacent non-tumor breast tissue specimens. Images show extensive expression of HCMV-IE, COX-2 and 5-LO in the same adjacent non-tumor tissue specimens (a). Lower panel present magnified images from upper panel. Majority of adjacent non-tumor breast tissues have focal expression of HCMV-IE, COX-2 and 5-LO (b). Concordant expression of HCMV-IE and COX-2/5-LO were detected in majority of adjacent non-tumor breast tissues (c, d)

Significant positive correlation between HCMV-IE protein, COX-2 and 5-LO expression

We further assessed whether there was a correlation between HCMV protein expression, COX-2, and 5-LO expression. A positive correlation was found between extensive HCMV-IE protein expression and extensive COX-2 or 5-LO protein expression in breast cancer tissue specimens (49% and 48%, respectively) (Fig. 2a–d). Significantly higher number of BC tissues had equal levels of both HCMV-IE/COX-2 and HCMV-IE/5-LO protein expression (concordant); 76% (51/67, P < 0.0001) and 69% (52/75, P = 0.0003), respectively (Fig. 2a–d). In adjacent non-tumor breast tissue, we instead found concordant levels of focal HCMV-IE/COX-2 and HCMV-IE/5-LO in 92% (24/26), and 83% (24/29) of the samples, respectively (Fig. 3a–d). Extensive expression of HCMV-IE and COX-2/5-LO was located in the same areas within the tissue sections. But in case of focal expression, these proteins were mainly expressed not only in the inflammatory cells but also in some tumor cells and in the cells of vessel walls.

Clinical data including Ki-67 labeling index, nodal status, and tumor stadium for BC patients are shown in Table 1. We found no association between HCMV-IE, COX-2 and 5-LO and lymph node involvement, tumor size or Ki-67 index (Supplemental Figs. 2, 3). At the time of our investigation, 92% (45/49) of BC patients were alive and median overall survival was 4.4 years. We also found no association between extensive HCMV infection and these inflammatory markers with patient outcome, but as only few patients in this cohort had relapsed or died, these results are still premature and somewhat uncertain.

HCMV induces COX-2 and 5-LO transcript levels in MCF-7 but not in MDA-MB-231 breast cancer cell lines

To assess whether HCMV can induce COX-2 and 5-LO expression in breast cancer cell lines, we infected MCF-7 and MDA-MB-231 with HCMV strain VR1814 at MOI of 5 and analyzed transcript levels of COX-2 and 5-LO by qPCR at 1, 3, and 6 dpi. In MCF-7 cells, HCMV infection resulted in a significantly induced COX-2 transcript expression at 3 and 6 dpi (P = 0.015 and P =0.008, respectively), and 5-LO at 6 dpi (P = 0.018) (Fig. 4a, b). However, HCMV infection had no effect on COX-2 or 5-LO transcript levels in MDA-MB-231 cells (Fig. 4c, d) as assessed with qPCR. Uninfected and HCMV-infected BC cell lines MCF-7 and MDA-MB-231 at 6 dpi were further analyzed for protein expression of COX-2 and 5-LO by FACS. Base line COX-2 protein levels were higher in MDA-MB-231 cells compared with MCF-7 cells (Figs. 5, 6). COX-2 was expressed in 58% and 40% of MDA-MB-231 and MCF-7 cells, respectively (Figs. 5, 6). 5-LO was expressed in only 6% of MDA-MB-231 and MCF-7 cells (Figs. 5, 6).

Fig. 4.

Fig. 4

Open in a new tab

Significant increase of COX-2 and 5-LO transcripts in HCMV infected MCF-7 but not in MDA-MB-231 breast cancer cell lines. Relative expression of COX-2 and 5-LO in MCF-7 (a, b, respectively) or MDA-MB-231 (c, d, respectively) infected with HCMV compared to non-infected cells was determined by qPCR at 1, 3 and 6 dpi. Data is presented as mean ± SD. Statistical significance is indicated as **P < 0.01, ***P < 0.001

Fig. 5.

Fig. 5

Open in a new tab

The number of cells expressing COX-2 but not 5-LO increased in HCMV infected MCF-7 cell populations compared with uninfected cells analyzed by using FACS. Eighty-two percent of HCMV infected MCF-7 cells express COX-2 protein and only 8.6% of the infected cells expressed 5-LO

Fig. 6.

Fig. 6

Open in a new tab

The number of cells expressing COX-2 and 5-LO increased in HCMV infected MDA-MB-231cell populations compared with uninfected cells analyzed by using FACS. Eighty-seven and 44% of HCMV infected MDA-MB-231 expressed COX-2 and 5-LO, respectively

The number of cells expressing COX-2 increased from 58 to 70% in HCMV-infected MDA-MB-231 and from 40 to 71% in MCF-7 cell population. The number of HCMV-induced 5-LO expressing cells increased from 6 to 29% in MDA-MB-231 population, but did not affect 5-LO expression in MCF-7 cells (Figs. 5, 6). Seventy percent of HCMV infected MDA-MB-231 and MCF-7 cells expressed COX-2 (Figs. 5, 6). Twenty-nine percent of HCMV-infected MDA-MB-231 cells, but only 3% of MCF-7 cells expressed 5-LO (Figs. 5, 6).

Discussion

The presence of HCMV, as well as other herpesviruses in different types of cancers has been studied by several groups with variable results (Cianchi et al. 2006; Rahbar et al. 2017). Several studies have reported a very high prevalence of HCMV in breast cancer and linked the virus activity levels to overall survival (Taher et al. 2013; Tsai et al. 2007). Consistent with these observations, we found HCMV protein expression in all breast cancer tissue specimens examined. Moreover, HCMV IE protein expression was extensive (defined as > 50% positive cells) in 72% of breast cancer samples, but only in 8% of adjacent non tumor tissues. These observations give support for a potential role of HCMV in breast cancer progression (Kumar et al. 2018; Rahbar et al. 2017). As it seems, HCMV infections can provide direct effects on tumor cells by expression of viral proteins that affect tumor biology-relevant mechanisms and by virus-induced inflammation. In fact, HCMV seems to contribute to all established Hallmarks of Cancer (Soroceanu and Cobbs 2011).

In support of this statement, we detected extensive expression of the inflammatory factors COX-2 and 5-LO in infiltrating breast cancer (58%, 53%, respectively), but less pronounced activity of these inflammatory mediators in adjacent non-tumor breast tissues (8% and 31%, respectively). These inflammatory factors were expressed in the tumor and in inflammatory cells. We also found a concordant extensive expression of COX-2, 5-LO, and HCMV-IE in breast cancer, suggesting that HCMV activity on tumor cells may be linked to COX-2 and 5-LO expression. This hypothesis was further supported by in vitro experiments demonstrating virus-induced transcript of both COX-2 and 5-LO and COX-2 protein expression in HCMV-infected MDA-231 and MCF-7 cells. However, we did not observe higher expression of COX-2 or 5-LO transcripts in HCMV-infected MDA-231 cells, which may be explained by the already high expression levels of COX-2 proteins in the more aggressive cell line MDA-231 that was originally established from a triple negative breast cancer (TNBC). Previous studies have reported high expression levels of COX-2 in TNBCs (Chikman et al. 2014; Mosalpuria et al. 2014), and we recently reported that HCMV protein expression was high in TNBC (Rahbar et al. 2017). Our results confirm previous studies demonstrating increased levels of COX-2, 5-LO, and their metabolites prostaglandins and leukotrienes in HCMV-infected cells both in vitro and in vivo (Maussang et al. 2009; Qiu et al. 2008; Hooks et al. 2006; Bongers et al. 2010).

HCMV-induced COX-2 expression is mediated by the constitutively active viral chemokine receptor homologue US28, which promotes inflammation, angiogenesis, and tumor formation (Maussang et al. 2009). US28 promotes angiogenesis and tumor formation via COX-2 induced production of IL-6, phosphorylation of STAT-3, and activation of nuclear factor-kappaB (Maussang et al. 2009). High COX-2 and 5-LO expression and production of inflammatory mediators will also attract inflammatory cells capable of releasing inflammatory factors and reactive oxygen species causing inflammation, oxidative DNA damage, and impaired DNA repair mechanisms (Coussens and Werb 2002). In a mouse model with targeted expression of US28 in colon, mice developed inflammation associated adenocarcinoma (Bongers et al. 2010). Consistent with an important role for the virus to induce COX-2 expression, COX-2 inhibition obstructs HCMV replication (Zhu et al. 2002) and reduces growth of HCMV positive tumors in animal models (Baryawno et al. 2011; Maussang et al. 2009). In addition, combined antiviral therapy targeting HCMV (Valganciclovir) and COX-2 (Celecoxib) prevents HCMV replication and PGE2 production, further reduced meduloblastoma and neuroblastoma cell proliferation in vitro (Baryawno et al. 2011; Wolmer-Solberg et al. 2013) and tumor size in meduloblastoma xenografts (Baryawno et al. 2011).

Taken together, these observations raise the question of a possible impact of HCMV on tumor progression through induced production of potent inflammatory factors such as COX-2 and 5-LO that through their effects on both tumor cells and the tumor microenvironment may enhance tumor malignancy grade and promote tumor progression.

Epidemiological studies in large patient cohorts have reported that the cancer risk and metastasis development is reduced in patients who are treated with non-selective COX inhibitors (Anderson et al. 2002; Burn et al. 2011; Xu 2002). The critical role of inflammatory COX-2 and 5-LO and their biological products, prostaglandin and leukotrienes in inflammation and their ability to stimulate signalling pathways contributing to angiogenesis, tumor growth, and invasiveness, further highlights them as potential targets for cancer therapy. Notably, inhibitors of 5-LO were efficiently used to block proliferation of breast cancer cells and a lipoxygenase inhibitor administrated to one breast cancer patient successfully reverted multiple brain metastasis (Flavin 2007; Hammamieh et al. 2007; Poeckel et al. 2006). In vitro experiments and animal models using specific COX-2 inhibitors show a reduction in proliferation and invasion of breast cancer cells and an effect on tumor development and growth (Bocca et al. 2011; Na et al. 2013; Silva et al. 2012). Consistent with these findings, specific or non-specific inhibition of COX-2 has successfully been used for prevention and therapy of breast cancer (Arun and Goss 2004). Selective COX-2 inhibitors appear to be more protective but in both cases, with a significant reduction in the breast cancer risk (Ashok et al. 2011). However, the inhibition of both COX-2 and 5-LO would have additive benefits by simultaneously targeting both pathways of arachidonic acid metabolism. Indeed, combined treatment with COX-2 and 5-LO inhibitors showed a stronger effect on tumor cell proliferation and induction of apoptosis in colon cancer cells (Che et al. 2016; Cianchi et al. 2006). However, these compounds may also involve a so far not considered anti-viral effect against HCMV to affect tumor growth (Schroer and Shenk 2008; Zhu et al. 2002). As selective COX-2 inhibitors may confer increased risk of cardiovascular diseases and stroke (Trelle et al. 2011; Back et al. 2012; Martinez-Gonzalez and Badimon 2007; Sibbald 2004), there is a need to develop a non-toxic drug with potential to inhibit COX-2 and 5-LO, with therapeutic action in human cancers (Gautam et al. 2017).

In conclusion, we detected higher grades of HCMV-IE, COX-2 and 5-LO in the majority of BC samples than in adjacent non-malignant tissue specimens and a significant correlation between extensive HCMV-IE, COX-2 and 5-LO protein levels in infiltrating BCs. These results suggest that inflammation driven by COX-2 and 5-LO in human BC might be induced by HCMV in some patients and promote tumor progression. Thus, we suggest that anti-viral therapy targeting HCMV and inhibitors targeting COX-2 and 5-LO should be evaluated as new therapeutic options in selected breast cancer patients.

Electronic supplementary material

Below is the link to the electronic supplementary material.

432_2019_2946_MOESM1_ESM.tif (3.3MB, tif)

Supplemental Fig. 1A. Expression of HCMV-IE protein in HCMV infected placenta using IHC staining. Detection of HCMV-IE protein in HCMV infected placenta tissue section with IHC served as positive control. Omitting primary antibody in the staining protocol served as negative control. (TIFF 3372 kb)

432_2019_2946_MOESM2_ESM.tif (1.6MB, tif)

Supplemental Fig. 1B. Expression of HCMV-IE protein could not be detected in breast cancer tissue using IHC staining. This HCMV negative breast tumor tissue section served as negative control for IHC staining used in this study. Staining for cytokeratin 5,6,8,17,19 served as positive control and cytokeratin 20 served as negative control in the staining protocol. (TIFF 1679 kb)

432_2019_2946_MOESM3_ESM.tif (478.8KB, tif)

Supplemental Fig. 2A, B. No association was observed between COX-2 expression levels in BC tissues and increasing number of involved lymph node from N0 to N1 and N2 (A). No association was found between HCMV-IE and lymph node involvement (B). (TIFF 479 kb)

432_2019_2946_MOESM4_ESM.tif (408.1KB, tif)

Supplemental Fig. 2C, D. No association was found between HCMV-IE or 5-LO and lymph node involvement or between HCMV-IE, COX-2, 5-LO and tumor size, and Ki-67 index (C, D). (TIFF 409 kb)

432_2019_2946_MOESM5_ESM.tif (605.2KB, tif)

Supplemental Fig. 3A-C. No association was found between HCMV-IE, COX-2, 5-LO, and tumor size (A-C). (TIFF 606 kb)

432_2019_2946_MOESM6_ESM.tif (508.1KB, tif)

Supplemental Fig. 3D-E. No association was found between HCMV-IE, COX-2, 5-LO, and KI-67 index (D-E). (TIFF 509 kb)

Acknowledgements

This study was funded by BILTEMA Foundation, Nexttobe, Stichting af Jochnicks Foundation, Sten A. Olssons Foundation for Research and Culture, Familjen Erling-Perssons Foundation, RATOS, independent Grants from Hoffmann La Roche, Torsten and Ragnar Söderbergs Foundations, Dan och Jane Olssons Foundation, Swedish Cancer Foundation, Swedish Medical Research Council, Swedish Society for Medical Research (SLS), Goljes Memory Foundation, Magnus Bergvalls Foundation, Swedish Society for Medical Research (SSMF), Percy Falks Foundation, Karolinska Institutet Foundation, IngaBritt och Arne Lundbergs Foundation and Tore Nilsons Foundation. In Norway, the study was supported by a Grant from the regional health administration (Helse Sør-Øst), funding from internal research funds of Akerhus University Hospital and by generous support provided by Bodil and Magne’s Cancer Research Fund, Oslo, Norway.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest and that the results presented in this paper have not been published previously. This cohort of breast cancer patients was previously investigated for HCMV protein expression and association with estrogen receptor-alpha (ER) and progesterone receptor (PGR) expression and the results were reported earlier (Rahbar et al. 2017).

Ethical approval

All procedures performed in this study involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. All patients gave their written informed consent prior to inclusion. The study protocol was approved by the regional ethical committee of south-east Norway, Oslo, Norway (2008/628-31/2, 577-06-04148, 06118 and 2014/895) and by the ethical committee at the Karolinska Institutet (Dnr: 2008/628-31/2), Stockholm, Sweden. Placental tissues were obtained after informed parental consent and according to the procedures approved by the Regulations of the French Ministry of Health.

Footnotes

Afsar Rahbar and Cecilia Söderberg-Naucler: shared senior authorship.

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Contributor Information

Afsar Rahbar, Email: afsar.rahbar@ki.se.

Cecilia Söderberg-Naucler, Email: cecilia.naucler@ki.se.

References

  1. Anderson WF, Umar A, Viner JL, Hawk ET. The role of cyclooxygenase inhibitors in cancer prevention. Curr Pharm Des. 2002;8:1035–1062. doi: 10.2174/1381612023394935. [DOI] [PubMed] [Google Scholar]
  2. Arun B, Goss P. The role of COX-2 inhibition in breast cancer treatment and prevention. Semin Oncol. 2004;31:22–29. doi: 10.1053/j.seminoncol.2004.03.042. [DOI] [PubMed] [Google Scholar]
  3. Ashok V, Dash C, Rohan TE, Sprafka JM, Terry PD. Selective cyclooxygenase-2 (COX-2) inhibitors and breast cancer risk. Breast. 2011;20:66–70. doi: 10.1016/j.breast.2010.07.004. [DOI] [PubMed] [Google Scholar]
  4. Avis I, et al. Five-lipoxygenase inhibitors can mediate apoptosis in human breast cancer cell lines through complex eicosanoid interactions. FASEB J. 2001 doi: 10.1096/fj.00-0866fje. [DOI] [PubMed] [Google Scholar]
  5. Back M, Yin L, Ingelsson E. Cyclooxygenase-2 inhibitors and cardiovascular risk in a nation-wide cohort study after the withdrawal of rofecoxib. Eur Heart J. 2012;33:1928–1933. doi: 10.1093/eurheartj/ehr421. [DOI] [PubMed] [Google Scholar]
  6. Balkwill F, Charles KA, Mantovani A. Smoldering and polarized inflammation in the initiation and promotion of malignant disease. Cancer Cell. 2005;7:211–217. doi: 10.1016/j.ccr.2005.02.013. [DOI] [PubMed] [Google Scholar]
  7. Baryawno N, et al. Detection of human cytomegalovirus in medulloblastomas reveals a potential therapeutic target. J Clin Invest. 2011;121:4043–4055. doi: 10.1172/JCI57147. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Benard M, et al. Human cytomegalovirus infection induces leukotriene B4 and 5-lipoxygenase expression in human placentae and umbilical vein endothelial cells. Placenta. 2014;35:345–350. doi: 10.1016/j.placenta.2014.03.022. [DOI] [PubMed] [Google Scholar]
  9. Bocca C, Bozzo F, Bassignana A, Miglietta A. Antiproliferative effects of COX-2 inhibitor celecoxib on human breast cancer cell lines. Mol Cell Biochem. 2011;350:59–70. doi: 10.1007/s11010-010-0682-4. [DOI] [PubMed] [Google Scholar]
  10. Bodaghi B, et al. Chemokine sequestration by viral chemoreceptors as a novel viral escape strategy: withdrawal of chemokines from the environment of cytomegalovirus-infected cells. J Exp Med. 1998;188:855–866. doi: 10.1084/jem.188.5.855. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Bongers G, et al. The cytomegalovirus-encoded chemokine receptor US28 promotes intestinal neoplasia in transgenic mice. J Clin Invest. 2010;120:3969–3978. doi: 10.1172/JCI42563. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Burn J, et al. Long-term effect of aspirin on cancer risk in carriers of hereditary colorectal cancer: an analysis from the CAPP2 randomised controlled trial. Lancet. 2011;378:2081–2087. doi: 10.1016/S0140-6736(11)61049-0. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Che XH, et al. Dual inhibition of COX-2/5-LOX blocks colon cancer proliferation, migration and invasion in vitro. Oncol Rep. 2016;35:1680–1688. doi: 10.3892/or.2015.4506. [DOI] [PubMed] [Google Scholar]
  14. Chen EP, Smyth EM. COX-2 and PGE2-dependent immunomodulation in breast cancer. Prostaglandins Other Lipid Mediators. 2011;96:14–20. doi: 10.1016/j.prostaglandins.2011.08.005. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Chikman B, et al. COX2 expression in high-grade breast cancer: evidence for prognostic significance in the subset of triple-negative breast cancer patients. Med Oncol. 2014;31:989. doi: 10.1007/s12032-014-0989-1. [DOI] [PubMed] [Google Scholar]
  16. Cianchi F, et al. Inhibition of 5-lipoxygenase by MK886 augments the antitumor activity of celecoxib in human colon cancer cells. Mol Cancer Ther. 2006;5:2716–2726. doi: 10.1158/1535-7163.MCT-06-0318. [DOI] [PubMed] [Google Scholar]
  17. Cinatl J, Jr, Vogel JU, Kotchetkov R, Wilhelm Doerr H. Oncomodulatory signals by regulatory proteins encoded by human cytomegalovirus: a novel role for viral infection in tumor progression. FEMS Microbiol Rev. 2004;28:59–77. doi: 10.1016/j.femsre.2003.07.005. [DOI] [PubMed] [Google Scholar]
  18. Cinatl J, Scholz M, Kotchetkov R, Vogel JU, Doerr HW. Molecular mechanisms of the modulatory effects of HCMV infection in tumor cell biology. Trends Mol Med. 2004;10:19–23. doi: 10.1016/j.molmed.2003.11.002. [DOI] [PubMed] [Google Scholar]
  19. Cobbs CS, et al. Human cytomegalovirus infection and expression in human malignant glioma. Cancer Res. 2002;62:3347–3350. [PubMed] [Google Scholar]
  20. Coussens LM, Werb Z. Inflammation and cancer. Nature. 2002;420:860–867. doi: 10.1038/nature01322. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. de Visser KE, Eichten A, Coussens LM (2006) Paradoxical roles of the immune system during cancer development. Nat Rev Cancer 6:24–37. http://www.nature.com/nrc/journal/v6/n1/suppinfo/nrc1782_S1.html [DOI] [PubMed]
  22. Denkert C, et al. Elevated expression of cyclooxygenase-2 is a negative prognostic factor for disease free survival and overall survival in patients with breast carcinoma. Cancer. 2003;97:2978–2987. doi: 10.1002/cncr.11437. [DOI] [PubMed] [Google Scholar]
  23. Dimberg J, Hong TT, Skarstedt M, Lofgren S, Zar N, Matussek A. Detection of cytomegalovirus DNA in colorectal tissue from Swedish and Vietnamese patients with colorectal cancer. Anticancer Res. 2013;33:4947–4950. [PubMed] [Google Scholar]
  24. Dirix LY, et al. Treatment of advanced hormone-sensitive breast cancer in postmenopausal women with exemestane alone or in combination with celecoxib. J Clin Oncol. 2008;26:1253–1259. doi: 10.1200/JCO.2007.13.3744. [DOI] [PubMed] [Google Scholar]
  25. Dreyling KW, Hoppe U, Peskar BA, Morgenroth K, Kozuschek W, Peskar BM. Leukotriene synthesis by human gastrointestinal tissues. Biochim Biophys Acta. 1986;878:184–193. doi: 10.1016/0005-2760(86)90145-1. [DOI] [PubMed] [Google Scholar]
  26. Flavin DF. A lipoxygenase inhibitor in breast cancer brain metastases. J Neurooncol. 2007;82:91–93. doi: 10.1007/s11060-006-9248-4. [DOI] [PubMed] [Google Scholar]
  27. Frascaroli G, Sinzger C. Distinct properties of human cytomegalovirus strains and the appropriate choice of strains for particular studies. Methods Mol Biol. 2014;1119:29–46. doi: 10.1007/978-1-62703-788-4_3. [DOI] [PubMed] [Google Scholar]
  28. Gautam S, Roy S, Ansari MN, Saeedan AS, Saraf SA, Kaithwas G. DuCLOX-2/5 inhibition: a promising target for cancer chemoprevention. Breast Cancer. 2017;24:180–190. doi: 10.1007/s12282-016-0723-2. [DOI] [PubMed] [Google Scholar]
  29. Hammamieh R, Sumaida D, Zhang X, Das R, Jett M. Control of the growth of human breast cancer cells in culture by manipulation of arachidonate metabolism. BMC Cancer. 2007;7:138. doi: 10.1186/1471-2407-7-138. [DOI] [PMC free article] [PubMed] [Google Scholar]
  30. Hanahan D, Weinberg RA. Hallmarks of cancer: the next generation. Cell. 2011;144:646–674. doi: 10.1016/j.cell.2011.02.013. [DOI] [PubMed] [Google Scholar]
  31. Harkins L, Volk AL, Samanta M, Mikolaenko I, Britt WJ, Bland KI, Cobbs CS. Specific localisation of human cytomegalovirus nucleic acids and proteins in human colorectal cancer. Lancet. 2002;360:1557–1563. doi: 10.1016/S0140-6736(02)11524-8. [DOI] [PubMed] [Google Scholar]
  32. Harkins LE, et al. Detection of human cytomegalovirus in normal and neoplastic breast epithelium. Herpesviridae. 2010;1:8. doi: 10.1186/2042-4280-1-8. [DOI] [PMC free article] [PubMed] [Google Scholar]
  33. Harris RE, Beebe-Donk J, Alshafie GA. Reduction in the risk of human breast cancer by selective cyclooxygenase-2 (COX-2) inhibitors. BMC Cancer. 2006;6:27. doi: 10.1186/1471-2407-6-27. [DOI] [PMC free article] [PubMed] [Google Scholar]
  34. Harris RE, Casto BC, Harris ZM. Cyclooxygenase-2 and the inflammogenesis of breast cancer. World J Clin Oncol. 2014;5:677–692. doi: 10.5306/wjco.v5.i4.677. [DOI] [PMC free article] [PubMed] [Google Scholar]
  35. Hennig R, et al. 5-Lipoxygenase and leukotriene B(4) receptor are expressed in human pancreatic cancers but not in pancreatic ducts in normal tissue. Am J Pathol. 2002;161:421–428. doi: 10.1016/S0002-9440(10)64198-3. [DOI] [PMC free article] [PubMed] [Google Scholar]
  36. Hooks JJ, et al. Human cytomegalovirus induced cyclooxygenase-2 in human retinal pigment epithelial cells augments viral replication through a prostaglandin pathway. Microbes Infect. 2006;8:2236–2244. doi: 10.1016/j.micinf.2006.04.010. [DOI] [PubMed] [Google Scholar]
  37. Howe LR. Inflammation and breast cancer. Cyclooxygenase/prostaglandin signaling and breast cancer. Breast Cancer Res. 2007;9:210. doi: 10.1186/bcr1678. [DOI] [PMC free article] [PubMed] [Google Scholar]
  38. Jemal A, Bray F, Center MM, Ferlay J, Ward E, Forman D. Global cancer statistics. CA Cancer J Clin. 2011;61:69–90. doi: 10.3322/caac.20107. [DOI] [PubMed] [Google Scholar]
  39. Kotenko SV, Saccani S, Izotova LS, Mirochnitchenko OV, Pestka S. Human cytomegalovirus harbors its own unique IL-10 homolog (cmvIL-10) Proc Natl Acad Sci USA. 2000;97:1695–1700. doi: 10.1073/pnas.97.4.1695. [DOI] [PMC free article] [PubMed] [Google Scholar]
  40. Kumar A, et al. The human cytomegalovirus strain DB activates oncogenic pathways in mammary epithelial cells. EBioMedicine. 2018;30:167–183. doi: 10.1016/j.ebiom.2018.03.015. [DOI] [PMC free article] [PubMed] [Google Scholar]
  41. Lucas KG, Bao L, Bruggeman R, Dunham K, Specht C. The detection of CMV pp65 and IE1 in glioblastoma multiforme. J Neurooncol. 2011;103:231–238. doi: 10.1007/s11060-010-0383-6. [DOI] [PubMed] [Google Scholar]
  42. Martinez-Gonzalez J, Badimon L. Mechanisms underlying the cardiovascular effects of COX-inhibition: benefits and risks. Curr Pharm Des. 2007;13:2215–2227. doi: 10.2174/138161207781368774. [DOI] [PubMed] [Google Scholar]
  43. Maussang D, et al. The human cytomegalovirus-encoded chemokine receptor US28 promotes angiogenesis and tumor formation via cyclooxygenase-2. Cancer Res. 2009;69:2861–2869. doi: 10.1158/0008-5472.CAN-08-2487. [DOI] [PubMed] [Google Scholar]
  44. Mosalpuria K, et al. Cyclooxygenase-2 expression in non-metastatic triple-negative breast cancer patients. Mol Clin Oncol. 2014;2:845–850. doi: 10.3892/mco.2014.327. [DOI] [PMC free article] [PubMed] [Google Scholar]
  45. Na YR, Yoon YN, Son DI, Seok SH. Cyclooxygenase-2 inhibition blocks M2 macrophage differentiation and suppresses metastasis in murine breast cancer model. PLoS One. 2013;8:e63451. doi: 10.1371/journal.pone.0063451. [DOI] [PMC free article] [PubMed] [Google Scholar]
  46. Petrucelli N, Daly MB, Pal T (1993) BRCA1- and BRCA2-associated hereditary breast and ovarian cancer. In: Adam MP, Ardinger HH, Pagon RA, Wallace SE, Bean LJH, Stephens K, Amemiya A (eds) GeneReviews((R)). Seattle, WA
  47. Poeckel D, et al. Inhibition of human 5-lipoxygenase and anti-neoplastic effects by 2-amino-1,4-benzoquinones. Med Chem. 2006;2:591–595. doi: 10.2174/1573406410602060591. [DOI] [PubMed] [Google Scholar]
  48. Qiu H, Straat K, Rahbar A, Wan M, Soderberg-Naucler C, Haeggstrom JZ. Human CMV infection induces 5-lipoxygenase expression and leukotriene B4 production in vascular smooth muscle cells. J Exp Med. 2008;205:19–24. doi: 10.1084/jem.20070201. [DOI] [PMC free article] [PubMed] [Google Scholar]
  49. Rahbar A, et al. Discordant humoral and cellular immune responses to Cytomegalovirus (CMV) in glioblastoma patients whose tumors are positive for CMV. Oncoimmunology. 2015;4:e982391. doi: 10.4161/2162402X.2014.982391. [DOI] [PMC free article] [PubMed] [Google Scholar]
  50. Rahbar A, et al. Low expression of estrogen receptor-alpha and progesterone receptor in human breast cancer tissues is associated with high-grade human cytomegalovirus protein expression. Clin Breast Cancer. 2017;17(7):526–535. doi: 10.1016/j.clbc.2017.04.013. [DOI] [PubMed] [Google Scholar]
  51. Reeves MB, MacAry PA, Lehner PJ, Sissons JGP, Sinclair JH. Latency, chromatin remodeling, and reactivation of human cytomegalovirus in the dendritic cells of healthy carriers. Proc Natl Acad Sci USA. 2005;102:4140–4145. doi: 10.1073/pnas.0408994102. [DOI] [PMC free article] [PubMed] [Google Scholar]
  52. Samanta M, Harkins L, Klemm K, Britt WJ, Cobbs CS. High prevalence of human cytomegalovirus in prostatic intraepithelial neoplasia and prostatic carcinoma. J Urol. 2003;170:998–1002. doi: 10.1097/01.ju.0000080263.46164.97. [DOI] [PubMed] [Google Scholar]
  53. Schroer J, Shenk T. Inhibition of cyclooxygenase activity blocks cell-to-cell spread of human cytomegalovirus. Proc Natl Acad Sci USA. 2008;105:19468–19473. doi: 10.1073/pnas.0810740105. [DOI] [PMC free article] [PubMed] [Google Scholar]
  54. Sibbald B. Rofecoxib (Vioxx) voluntarily withdrawn from market. CMAJ. 2004;171:1027–1028. doi: 10.1503/cmaj.1041606. [DOI] [PMC free article] [PubMed] [Google Scholar]
  55. Silva HC, Alves V, Nogueira LA, Rosa MS, Carvalho L, Regateiro F. Impairment of breast cancer cell invasion by COX-2-specific inhibitor NS398: roles of CXCR1 and of uPA system. Med Oncol. 2012;29:1468–1476. doi: 10.1007/s12032-011-9995-8. [DOI] [PubMed] [Google Scholar]
  56. Slinger E. HCMV-encoded chemokine receptor US28 mediates proliferative signaling through the IL-6-STAT3 axis. Sci Signal. 2010 doi: 10.1126/scisignal.2001180. [DOI] [PubMed] [Google Scholar]
  57. Söderberg-Nauclér C, Fish KN, Nelson JA. Reactivation of latent human cytomegalovirus by allogeneic stimulation of blood cells from healthy donors. Cell. 1997;91:119–126. doi: 10.1016/S0092-8674(01)80014-3. [DOI] [PubMed] [Google Scholar]
  58. Soroceanu L, Cobbs CS. Is HCMV a tumor promoter? Virus Res. 2011;157:193–203. doi: 10.1016/j.virusres.2010.10.026. [DOI] [PMC free article] [PubMed] [Google Scholar]
  59. Steele VE, et al. Lipoxygenase inhibitors as potential cancer chemopreventives. Cancer Epidemiol Biomark Prev. 1999;8:467–483. [PubMed] [Google Scholar]
  60. Tafvizi F, Fard ZT. Detection of human cytomegalovirus in patients with colorectal cancer by nested-PCR. Asian Pac J Cancer Prev. 2014;15:1453–1457. doi: 10.7314/APJCP.2014.15.3.1453. [DOI] [PubMed] [Google Scholar]
  61. Taher C, et al. High prevalence of human cytomegalovirus proteins and nucleic acids in primary breast cancer and metastatic sentinel lymph nodes. PLoS One. 2013;8:e56795. doi: 10.1371/journal.pone.0056795. [DOI] [PMC free article] [PubMed] [Google Scholar]
  62. Taher C, et al. High prevalence of human cytomegalovirus in brain metastases of patients with primary breast and colorectal cancers. Transl Oncol. 2014;7:732–740. doi: 10.1016/j.tranon.2014.09.008. [DOI] [PMC free article] [PubMed] [Google Scholar]
  63. Trelle S, et al. Cardiovascular safety of non-steroidal anti-inflammatory drugs: network meta-analysis. BMJ. 2011;342:c7086. doi: 10.1136/bmj.c7086. [DOI] [PMC free article] [PubMed] [Google Scholar]
  64. Tsai J-H, et al. Relationship between viral factors, axillary lymph node status and survival in breast cancer. J Cancer Res Clin Oncol. 2007;133:13–21. doi: 10.1007/s00432-006-0141-5. [DOI] [PubMed] [Google Scholar]
  65. Vossen MT, Westerhout EM, Soderberg-Naucler C, Wiertz EJ. Viral immune evasion: a masterpiece of evolution. Immunogenetics. 2002;54:527–542. doi: 10.1007/s00251-002-0493-1. [DOI] [PubMed] [Google Scholar]
  66. Wang D, DuBois RN. Eicosanoids and cancer. Nat Rev Cancer. 2010;10:181–193. doi: 10.1038/nrc2809. [DOI] [PMC free article] [PubMed] [Google Scholar]
  67. Wolmer-Solberg N, et al. Frequent detection of human cytomegalovirus in neuroblastoma: a novel therapeutic target? Int J Cancer. 2013;133:2351–2361. doi: 10.1002/ijc.28265. [DOI] [PubMed] [Google Scholar]
  68. Xu XC. COX-2 inhibitors in cancer treatment and prevention, a recent development. Anticancer Drugs. 2002;13:127–137. doi: 10.1097/00001813-200202000-00003. [DOI] [PubMed] [Google Scholar]
  69. Zhu H, Cong JP, Yu D, Bresnahan WA, Shenk TE. Inhibition of cyclooxygenase 2 blocks human cytomegalovirus replication. Proc Natl Acad Sci USA. 2002;99:3932–3937. doi: 10.1073/pnas.052713799. [DOI] [PMC free article] [PubMed] [Google Scholar]

Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Supplementary Materials

432_2019_2946_MOESM1_ESM.tif (3.3MB, tif)

Supplemental Fig. 1A. Expression of HCMV-IE protein in HCMV infected placenta using IHC staining. Detection of HCMV-IE protein in HCMV infected placenta tissue section with IHC served as positive control. Omitting primary antibody in the staining protocol served as negative control. (TIFF 3372 kb)

432_2019_2946_MOESM2_ESM.tif (1.6MB, tif)

Supplemental Fig. 1B. Expression of HCMV-IE protein could not be detected in breast cancer tissue using IHC staining. This HCMV negative breast tumor tissue section served as negative control for IHC staining used in this study. Staining for cytokeratin 5,6,8,17,19 served as positive control and cytokeratin 20 served as negative control in the staining protocol. (TIFF 1679 kb)

432_2019_2946_MOESM3_ESM.tif (478.8KB, tif)

Supplemental Fig. 2A, B. No association was observed between COX-2 expression levels in BC tissues and increasing number of involved lymph node from N0 to N1 and N2 (A). No association was found between HCMV-IE and lymph node involvement (B). (TIFF 479 kb)

432_2019_2946_MOESM4_ESM.tif (408.1KB, tif)

Supplemental Fig. 2C, D. No association was found between HCMV-IE or 5-LO and lymph node involvement or between HCMV-IE, COX-2, 5-LO and tumor size, and Ki-67 index (C, D). (TIFF 409 kb)

432_2019_2946_MOESM5_ESM.tif (605.2KB, tif)

Supplemental Fig. 3A-C. No association was found between HCMV-IE, COX-2, 5-LO, and tumor size (A-C). (TIFF 606 kb)

432_2019_2946_MOESM6_ESM.tif (508.1KB, tif)

Supplemental Fig. 3D-E. No association was found between HCMV-IE, COX-2, 5-LO, and KI-67 index (D-E). (TIFF 509 kb)

Articles from Journal of Cancer Research and Clinical Oncology are provided here courtesy of Springer

RESOURCES