Skip to main content
NCBI home page
Cell Cycle logoLink to Cell Cycle
. 2021 Mar 22;20(7):689–701. doi: 10.1080/15384101.2021.1899519

Circular RNA SMARCA5 functions as an anti-tumor candidate in colon cancer by sponging microRNA-552

Shiwei Yang a,b,c,d,#, Shanyu Gao e,#, Tongming Liu f, Junning Liu a,b,c,d, Xia Zheng a,b,c,d, Zhi Li a,b,c,d,✉
PMCID: PMC8078666  PMID: 33749508

ABSTRACT

It was reported that circular RNA (circRNA) circSMARCA5, as a tumor-related molecule, could modulate development of cancers, including prostatic cancer and cervical cancer. Nevertheless, the essential function of circSMARCA5 in colon cancer has not yet been confirmed. We aimed to investigate the role of circSMARCA5 in colon cancer. CircSMARCA5 expression in tumor cells was detected using RT-qPCR. CCK-8, colony formation, flow cytometry and Transwell assays evaluated the influences of circSMARCA5 in colon cancer cells. RT-qPCR, prediction database and luciferase report assay were accomplished for revealing the correlation between circSMARCA5 and miR-552. After transfection with miR-552 mimic, colon cancer cell behaviors were re-evaluated. Wnt and YAP1 pathways were explored by western blot. Our data presented that circSMARCA5 was under-expressed in colon cancer tissues. Transfection with overexpressing circSMARCA5 plasmid restrained growth, migration and invasion of colon cancer cells. Besides, circSMARCA5 directly sponged to miR-552 and miR-552 up-regulation offset the effects of circSMARCA5 on SW480 and SW620 cells. Furthermore, circSMARCA5 inactivated Wnt and YAP1 pathways by inhibiting miR-552. Anti-tumor role of sircSMARCA5 was showed in colon cancer cells as sponging miR-552 and blocking Wnt and YAP1 pathways.

KEYWORDS: Circular RNA SMARCA5, colon cancer, microrna-552, wnt pathway, yap1 pathway

Introduction

Colon cancer, the most general malignancy derived from the colon and rectum, is still the contributive cause of cancer-connected mortality worldwide [1,2]. In recent years, the incidence and mortality of colon cancer in China have increased year by year due to the changes in living environment and dietary structure [3]. Statistical data presented that there were 245,000 new cases and 139,000 deaths of colon cancer in 2012. The linchpin methods for colon cancer treatment are dependent on surgical and systemic chemotherapy. However, the 5-year survival rate of patients with colon cancer reaches a plateau of approximately 50% [4]. Hence, it is significant that providing recognizable specific tumor molecular marker for colon cancer can improve the diagnosis and individualized treatment of colon cancer.

Circular RNAs (circRNAs), a class of non-linear single-stranded non-coding RNAs, unlike conventional linear RNAs, lack typical terminal structures (5ʹ cap-like structure and 3ʹ polyadenylation tail) [5]. Increasing studies on the characteristics and functions of circRNAs corroborated that circRNAs were not only a group of highly expressed RNA molecules that could act as a sponge for miRNAs, but also regulated of gene expression at the level of transcription and translation as clinical biomarkers in colon cancer [6,7]. Higher level of ciRS-7 in colon cancer tissues compared with para-carcinoma tissues, better reflect circRNA expression and tumor depth [8]. CircRNA_0001178 and circRNA_0000826 were reported to be overexpressed in the specimens of colon cancer patients, implying unique potential diagnostic and prognostic markers [9].

CircSMARCA5 is derived from SWI/SNF related, matrix associated, actin-dependent regulator of chromatin, subfamily a, member 5 (SMARCA5) on the sense stand of chromosome 4 [10]. The carcinogenetic function of circSMARCA5 was reflected in its over-expression among prostate cancer cells [11]. In a present research, Yu et al. manifested the down-regulated status of circSMARCA5 in several liver cancer specimens for illustration of the therapeutical utilization of this molecular marker [12]. When the down-expressive alteration of circSMARCA5 was more accurately detected in non-small cell lung cancer tissues and cell lines, it was disclosed that circSMARCA5 expression level could be predictive of tumor growth status and circSMARCA5 could be further selected as remedial application [13]. Nonetheless, the role of circSMARCA5 in colon cancer is less well documented.

Consequently, in this research, we executed a systematic exploration regarding the impacts of circSMARCA5 on colon cancer cell behavioral consequences connected with anti-grow, anti-migratory and anti-invasive behavior to acquire perception in probable molecular targets to be investigated in clinical research.

Materials and methods

Collection of tissues and cultivation of cell lines

In total, we recruited 35 newly diagnosed patients with histologically confirmed breast cancer from May 2017 to April 2019 to participate in this research. Samples from colon cancer (n = 35) and para-cancerous tissues (n = 35) were obtained before treatment. All samples were frozen in liquid nitrogen container and reposited until analysis. All tissues were collected in accordance with the relevant approval from the ethical committee of the First Affiliated Hospital of Shandong First Medical University (Jinan, China). Patients have written informed consent.

Two kinds of colon cancer cell line, SW480 (derived from primary colorectal cancer tissues) and SW620 (derived from metastatic colorectal cancer), were purchased from the Cell bank of the Chinese Academy of Sciences (Shanghai, China) and cultured in the following medium: Leibovitz’s L-15 (GibcoTM, Rockville, MD, USA), 10% qualified and heat inactivated fetal bovine serum (FBS, GibcoTM). All cell lines were grown before tests in a humidified hatcher at 37°C, 5% CO2.

Quantitative analysis of circSMARCA5 and miR-552 expression

RNAiso Plus (Takara Bio, Mountain View, CA, USA) was utilized to extract total RNA, according to the manufacturer’s instructions. cDNA was synthesized from 1 mg of total RNA utilizing the PrimeScript™ RT Master Mix (Takara Bio). The quantitative analysis of circSMARCA5 and miR-552 expression was performed by using TB Green® Premix Ex Taq™ II (Takara Bio) on Thermal Cycler Dice Real Time System III (Takara Bio). GAPDH was used as an internal control for the quantitation of circSMARCA5 expression. And U6 was used as an internal control for the quantitation of miR-552. The analysis of relative expression level was accomplished according to the 2−ΔΔCt method [14].

Transfection of plasmids

The full-length sequence of circSMARCA5 can be obtained in Circbank online database (http://www.circbank.cn/index.html) and circBase ID is hsa_circ_0001445. After amplification using PCR, the sequence was cloned into PLCDH-cir vector (Geneseed, Guangzhou, China) to generate circSMARCA5 overexpressing plasmid. MiR-552 mimic (sense 5ʹ-AAC AGG UGA CUG GUU AGA CAA-3ʹ, antisense 5ʹ-GUC UAA CCA GUC ACC UGU UUU-3ʹ) and the NC mimic were synthesized by Sango (Shanghai, China). Transfection was carried out using Xfect RNA Transfection Reagent (Takara Bio). The colon cancer cells were transfected with 1.25 µg of plasmid with 5 µL Xfect RNA Transfection Polymer. Until the time of 48 h post-transfection, relative expression levels of circSMARCA5 and miR-552 were analyzed to verify transfection efficiency.

Examination of cell viability

For the examination of cell viability, 96-well plate was seeded with SW480 and SW620 cells (105 cells/well). After pre-incubation for 24 h, each well was added with 10 μL of the CCK-8 solution (Abbkine Scientific, California, CA, USA), followed by 4 h incubation. The absorbance at 450 nm was measured on a microplate reader (BioTek, Winooski, VT, USA).

Examination of cell colony formation

SW480 and SW620 cells (1 × 104) were plated in 35-mm culture dishes and pre-incubated for 14 days to form cell colony. After fixation with 4% paraformaldehyde, the forming colonies were dyed with crystal violet and imaged under microscope (Leica, Wetzlar, Germany).

Examination of cell apoptosis

For the examination of cell apoptosis, SW480 and SW620 cells (3 × 105) cells were collected in ice-cold phosphate buffer saline (PBS, Cwbio, Jiangsu, China) and then resuspended in 100 μL 1 × Annexin V Binding Buffer (Abbkine Scientific). Every 100 μL cell suspension was added with 5  μL of Annexin V-AbFlourTM 488 (Abbkine Scientific) and 2  μL of 100  µg/mL Propidium Iodide (PI, Abbkine Scientific) in flow tube. After the incubation for 15 min, extra 400 μL of 1 × Annexin V Binding Buffer was dispensed to each tube. Flow cytometry was implemented for the analysis of apoptotic cells under 491 nm and 535 nm excitation. The results were disposed by employing FlowJo software (Beckman Coulter, Fullerton, CA, USA).

Examination of cell migration and invasion

For the examination of cell migration, Tranwell inserts (Corning life sciences, Corning, NY, USA) were set on a 24-well plate. The 200 μL of 1 × 105 cells were added into the upper chambers, while 800 μL of 10% FBS medium was dispensed in the under chambers. Following pre-incubation for 24 h, the migrated cells in the 8 μm PET membranes of Tranwell inserts were stained by using giemsa (Solarbio, Beijing, China). Migratory cells were imaged under microscope (Leica) and quantified by employing ImageJ software (National Institutes of Health, Bethesda, MD, USA). The relative migration (%) was analyzed. For the examination of cell invasion, Matrigel (Corning life sciences) diluted in FBS-free medium was pre-plated on the Transwell inserts. After Matrigel concretion, the same protocols of migration experiment were performed. Similarly, invasive cells were photographed and counted.

Examination of binding between circSMARCA5 and miR-552

For examining the binding between circSMARCA5 and miR-552, we performed dual-luciferase reporter assay. CircSMARCA5WT (or circSMARCA5MUT) was introduced into cells together with miR-552 mimic (or mimic NC). After cell transfection, cells were lysed with special lysis buffer of Dual Luciferase Reporter Gene Assay Kit (Beyotime, Shanghai, China). Each well of 96-well plate was added with 100 μL of cell supernatant and 100 μL of firefly luciferase detection solution. The light unit under 560 nm was analyzed for the firefly luciferase. After completing the above steps for determination of firefly luciferase, 100 μL of renilla luciferase detection solution was added to determine the renilla luciferase light unit under 465 nm. Finally, the firefly luciferase activity was normalized with renilla activity.

Examination of protein expression

For the examination of protein expression, colon cancer cells were lysed with RIPA buffer (Cell signaling technology, CST, Danvers, MA, USA). Lysates were quantified for the protein concentration by using Bradford Kit (Beyotime). Denatured protein was mixed with protein loading buffer (Beyotime), and then equivalent amount of samples were loaded on SDS-PAGE gel for the separation of different molecular weight proteins. The polyvinylidene difluoride (PVDF, Beyotime) membranes that transferred with protein bands were reacted with primary antibodies overnight. The rabbit polyclonal primary antibodies obtained from CST were listed: p53 (#2527, 53 kDa), p21 (#2947, 21 kDa), CyclinD1 (#2922, 36 kDa), Bax (#5023, 20 kDa), Cleaved-Caspase-3 (#9661, 17 kDa), wnt3a (#2391, 42 kDa), β-catenin (#9562, 92 kDa), p-YAP1 (#13,008, 965 kDa), t-YAP1 (#4962, 75 kDa) and β-actin (#4970, 45 kDa). After reaction with HRP-linked anti-rabbit IgG (#7074, CST), the membranes were immersed in SignalFire™ Plus ECL Reagent (CST). The protein bands on the membranes were visualized by employing Image Lab™ Software (Bio-Rad, Hercules, CA, USA).

In vivo assessment of overexpressing circSMARCA5 efficacy in colon cancer

BALB/c nude mice, about 18–20 g bodyweight, were implanted subcutaneously at the back with transfected SW480 cells (1 × 106 cells/mL) in mixture of medium and PBS. The mice were randomly divided into three groups as follows: non-transfected group, Vector-transfected group and circSMARCA5-transfected group. Every group was raised for 28 days. The tumor size was estimated every 4 days, in two dimensions utilizing a calliper and the tumor volume was calculated with (0.5 × A × B [2]) mm [3]. After 28 days, all mice were killed to collect the tumors and the tumor specimens were weighted.

Analysis of data

The data from three independent tests were disposed as Mean  +  SD on GraphPad Prism 6 (GraphPad Software, San Diego, CA, USA). Significant statistical difference, which was set as p < 0.05, was identified using unpaired test and two-way ANOVA.

Results

Level of circSMARCA5 in colon cancer tissues

First of all, we appraised the level of circSMARCA5 in colon cancer tissues. In agreement with data obtained in other cancer specimens (myeloma [15]), we observed a significant under-expression of circSMARCA5 in a series of 35 colon cancer, compared with 35 non-tumor tissues (p < 0.01, Figure 1a). The functional effects of circSMARCA5 were scrutinized in both cell lines (SW480 and SW620) by cell transfection of synthetic circSMARCA5 overexpressing plasmid. We observed that circSMARCA5 was effectively up-regulated in SW480 and SW620 cell lines (p < 0.01, Figure 1b).

Figure 1.

Figure 1.

Open in a new tab

Level of circSMARCA5 in colon cancer tissues. (a) Expression levels of circSMARCA5 in colon cancer clinical specimens (n = 35) and the corresponding non-tumor tissues (n = 35) were measured by RT-qPCR. (b) RT-qPCR analysis of circSMARCA5 expression in SW480 and SW620 cells transfected with circSMARCA5 overexpressing plasmid or vector. ** p < 0.01

Impacts of circSMARCA5 on colon cancer growth, migration and invasion

Preceding finding disclosed that overexpression of circSMARCA5 reduced lung cancer cell proliferation [13]. Therefore, we assumed that circSMARCA5 level could alter colon cancer cell behaviors. We showed that up-regulation of circSMARCA5 in SW480 and SW620 cells repressed cell viability (p < 0.01, Figure 2a) and obviously inhibited cell growth after 72 h and 96 h transfection (p < 0.01, Figure 2b). In addition, colony formation was also elevated by overexpressing circSMARCA5 (p < 0.01, Figure 2c). However, in circSMARCA5 overexpressing plasmid-transfected cells, cell apoptosis was conspicuously promoted (p < 0.01, Figure 2d). Furthermore, circSMARCA5 overexpression in colon cancer cells enhanced p53, p21 protein levels and decreased CyclinD1 expression (p < 0.05, p < 0.001, Figure 2e). In addition, remarkable enhancement was observed for Bax and Cleaved-Caspase-3 protein expression (p < 0.001, Figure 2f). Furthermore, based on the results of in vivo experiments, we proved that overexpression of circSMARCA5 remarkably decreased tumor volume after 16 days, 20 days, 24 days and 28 days of subcutaneous injection in BALB/c nude mice (p < 0.05, p < 0.01, p < 0.001, Figure 3a). More importantly, after 28 days, the mice were killed, and tumor weight was detected. As presented in Figure 3b, tumor weight of circSMARCA5 overexpressing group was significantly lower than that of Vector group (p < 0.01).

Figure 2.

Figure 2.

Open in a new tab

Impacts of circSMARCA5 on colon cancer growth. SW480 and SW620 cells were transfected with circSMARCA5 overexpressing plasmid/Vector. (a) Viability assessed by MTT assay 48 h after transfection. (b) The growth curves evaluated by using MTT assay. (c) Colony formation assessed by crystal violet. (d) Apoptosis assessed by flow cytometry. Western blot of total protein extracted from transfected cells were probed for (e) p53, p21, CyclinD1, (f) Bax and cleaved-caspase-3. ** p < 0.01, *** p < 0.001

Figure 3.

Figure 3.

Open in a new tab

Impacts of circSMARCA5 on colon cancer growth in vivo. BALB/c nude mice were subjected to subcutaneous injection of SW480 cells that were transfected with circSMARCA5 overexpressing plasmid/vector. (a) Tumor volume and (b) weight was measured. * p < 0.05,** p < 0.01, *** p < 0.001

Meanwhile, it was also proved that cellular migration and invasion were noticeably weakened by circSMARCA5 overexpression, compared to vector-transfected colon cancer cells (p < 0.01, Figure 4a-4b). Collectively, these findings indicated that circSMARCA5 displayed tumor suppressor function in colon cancer-derived cell lines.

Figure 4.

Figure 4.

Open in a new tab

Impacts of circSMARCA5 on colon cancer migration and invasion. SW480 and SW620 cells were transfected with circSMARCA5 overexpressing plasmid. (a) Migration capacity assessed by Transwell assay. (b) Invasion capacity assessed by Matrigel Transwell assay. ** p < 0.01

Direct binding between circSMARCA5 and miR-552

Identifying circSMARCA5 as a suppressor of colon cancer, we took an interest in exploring which miRNA circSMARCA5 might modulate in colon cancer cells. It was observed that miR-552 expression was down-regulated in circSMARCA5-overexpressed cells (p < 0.01, Figure 5a). To ascertain whether miR-552 was a direct miRNA of circSMARCA5 as bioinformatics prediction showed (Figure 5b), we executed luciferase experiment in 293 cells by utilizing the reporter plasmid being inserted either wild-type (WT) or mutant (MUT) sequence of circSMARCA5 (circSMARCA5WT and circSMARCA5MUT). The data revealed a significant reduction in luciferase activity for circSMARCA5WT and miR-552 mimic group, compared with circSMARCA5WT and NC mimic group (p < 0.01, Figure 5c). Nevertheless, the luciferase activity did not remarkably differ upon expression of circSMARCA5MUT plasmid. These data indicated that circSMARCA5 downregulated the expression of miR-552 by directly binding to miR-552 sequence.

Figure 5.

Figure 5.

Open in a new tab

Direct binding between circSMARCA5 and miR-552. (a) RT-qPCR analysis of miR-552 expression in SW480 and SW620 cells transfected with circSMARCA5 overexpressing plasmid or vector. (b) Binding sites between circSMARCA5 and miR-552. (c) Luciferase reporter plasmids carrying the wild-type (WT) or mutant (MUT) sequence of circSMARCA5 (circSMARCA5WT or circSMARCA5MUT) were transfected into 293 cells with miR-552 mimic (or mimic NC). The 293 cells were harvested 24 h later for luciferase reporter assay. ** p < 0.01

Participation of miR-552 in circSMARCA5-regulated colon cancer cell behaviors

To identify whether miR-552 contributed to the impacts of circSMARCA5 in colon cancer cells, SW480 and SW620 cells were transfected with miR-552 mimic to elevate miR-552 level (p < 0.01, Figure 6a). Interestingly, both overexpression of circSMARCA5 and miR-552 evidently facilitated colon cancer cell viability and colony formation (p < 0.05, Figure 6b-6d). By contrast, SW480 and SW620 cells presented remarkable declination of cell apoptosis after transfection with circSMARCA5 overexpressing plasmid and miR-552 mimic (p < 0.05, Figure 6e). Meanwhile, we characterized the influences of miR-552 in circSMARCA5-regulated tumor cell behaviors by quantifying proliferation-associated and apoptosis-associated markers. As presented in Figure 6f, the reduction of proliferation-associated factors (p53 and p 21) and the increasing of CyclinD1 were obvious in cells that were overexpressed with circSMARCA5 and miR-552 (p < 0.05, p < 0.001). As for apoptotic proteins, cells transfected with circSMARCA5 overexpressing plasmid and miR-552 mimic were lowly positive for Bax and cleaved-caspase-3 (p < 0.01, p < 0.001, Figure 6g). Coincidentally, overexpression of miR-552 reversed the decrease of colon cancer cell migration and invasion in circSMARCA5 overexpressed group (p < 0.05, Figure 7a-7b). Collectively, the above-mentioned consequences corroborated that miR-552 was regulated by circSMARCA5, and circSMARCA5 overexpression inhibited SW480 and SW620 cell behaviors by suppressing miR-552.

Figure 6.

Figure 6.

Open in a new tab

Participation of miR-552 in circSMARCA5-regulated colon cancer cell growth. (a) RT-qPCR analysis of miR-552 expression in SW480 and SW620 cells transfected with miR-552 mimic (or mimic NC). SW480 and SW620 cells were transfected with circSMARCA5 overexpressing plasmid (or vector) and miR-552 mimic (or mimic NC). (b) Viability assessed by MTT assay 48 h after transfection. (c) The growth curves evaluated by using MTT assay. (d) Colony formation assessed by crystal violet. (e) Apoptosis assessed by flow cytometry. Western blot of total protein extracted from transfected cells were probed for (f) p53, p21, CyclinD1 (g) Bax and cleaved-caspase-3. * p < 0.05, ** p < 0.01, *** p < 0.001

Figure 7.

Figure 7.

Open in a new tab

Participation of miR-552 in circSMARCA5-regulated colon cancer cell migration and invasion. SW480 and SW620 cells were transfected with circSMARCA5 overexpressing plasmid (or vector) and miR-552 mimic (or mimic NC). (a) Migration capacity assessed by Transwell assay. (b) Invasion capacity assessed by Matrigel Transwell assay. * p < 0.05, ** p < 0.01

Impacts of circSMARCA5 on Wnt and YAP1 pathways

Because miR-552 could enhance colon cancer cell migration and invasion, which process was related to Wnt pathway activation [16], we ultimately probed effects of circSMARCA5 and miR-552 on Wnt and YAP1 pathways. CircSMARCA5 suppressed the protein biosynthesis activity of wnt3a, β-catenin and phosphorylated YAP1 (p-YAP1) in SW480 and SW620 cells, without affecting total YAP1 (t-YAP1) expression (p < 0.001, Figure 8a-8b). On the other hand, miR-552 mimic transfection resulted in significant increasing in wnt3a, β-catenin and p-YAP1 levels in circSMARCA5-upregulated cells. These data indicated circSMARCA5 was functionally required for miR-552 inhibition in interrupting Wnt and YAP1 pathways.

Figure 8.

Figure 8.

Open in a new tab

Impacts of circSMARCA5 on Wnt and YAP1 pathways. SW480 and SW620 cells were transfected with circSMARCA5 overexpressing plasmid (or vector) and miR-552 mimic (or mimic NC). (a-b) Western blot of total protein extracted from transfected cells were probed for wnt3a, β-catenin and phosphorylated YAP1 (p-YAP1) and total YAP1 (t-YAP1). *** p < 0.001

Discussion

The postoperative recurrence and metastasis of patients with colon cancer are the primary causes for the poor prognosis of patients. Cellular behavioral changes occurring during colon cancer development were controlled by multiple genetic regulations between cancer cells. The molecular basis of colon cancer development remains mainly unascertained. In the present subject, we manifested that circSMARCA5 had the ability to decrease aggressiveness of colon cancer cells (growth, migration and invasion) through regulating miR-552.

By identifying abnormally expressed circRNA in colon cancer tissues, it was found that circSMARCA5 was down-expressed in colon cancer, which expression was in accordance with its established under-regulation in cervical cancer [17]. Meanwhile, the connection of circSMARCA5 with splicing factors-regulated migration was formerly covered [18] and the dis-synergized function of circSMARCA5 with cancer progression was previously probed in other cancers such as non-small cell lung cancer [19], myeloma [15] and glioblastoma [18]. No endeavor was made to examine impact of circSMARCA5 in colon cancer cell behaviors. We here manifested that over-regulation of circSMARCA5 was sufficient to inhibit colon cancer cell viability and colony formation and decreased cell apoptosis in combination with the alternations of proliferation-related proteins (p53, p21 and CyclinD1) and apoptosis-related markers (Bax and cleaved-caspase-3), implying that circSMARCA5 might suppress colon cancer cell growth. Additionally, circSMARCA5 also reduced colon cancer cell migratory and invasive abilities, being indicative of anti-tumor function of circSMARCA5.

Interestingly, it was coincidentally detected that miR-552 was down-regulated in circSMARCA5-overexpressed colon cancer cells, suggesting a potential role for miR-552 in the colon cancer cell behaviors. Based on online circRNA databases [20], circSMARCA5-mediated dysregulated miRNAs have been extensively explored. One study reported the sponge of circSMARCA5 toward miR-620 [17], whereas other showed the binding between circSMARCA5 and miR-19b-3p [19]. Further, we determined the targeting connection between circSMARCA5 and miR-552. In osteosarcoma cell line, over-regulated level of miR-552 was efficacious to promote cell growth by negatively regulating WIF1 expression, hinting a contribution of miR-552 in cancer development [21]. However, cell proliferation and migration of colon cancer cells was inhibited by down-modulating miR-552 expression [16,22]. We reported that up-regulation of miR-552 partially restored the growth, migration and invasion of colon cancer cells after overexpressing circSMARCA5. These alterations might be associated with activation of cellular signaling pathway in colon cancer cells.

Wnt signaling pathway is one of the important pathways for the early occurrence and development of colon cancer [23]. Previous study revealed that β-catenin, a key signal factor that mediated cell-to-cell adhesion and gene transcription regulation, was involved in the growth, invasion, and distant metastasis of colon cancer [24]. The activation of the Wnt pathway was an early event in colon cancer. By controlling colon cancer cells, Wnt pathway could play a decisive role in the development of colon cancer and was an important target for the prevention of colon cancer [25]. YAP1, a core element of the Hippo signaling pathway, is considered a proto-oncogene due to the over-expression in various types of human cancers [26,27]. In addition, high level of YAP1 in colon cancer is associated with poorer patient prognosis [28]. Consistent with previous data, our findings disclosed that the blockage of Wnt and YAP1 pathways was presented in circSMARCA5-overepxressed colon cancer cells, and the up-regulation miR-552 re-activated Wnt and YAP1 pathways. The results indicated that Wnt and YAP1 pathways might dedicate to the anti-cancer function of circSMARCA5 in colon cancer cells.

Collectively, our work demonstrated that both of circSMARCA5 and miR-552 in colon cancer cells might be influential molecules that colon cancer cells could resist to growing, migratory and invasive processes. Hence, this study smoothed the way for targeting circSMARCA5 involved in colon cancer, the up-regulation of which might be advantageous for the treatment of colon cancer.

Acknowledgments

None

Funding Statement

The work was supported by Jinan Clinical Medical Science and Technology Innovation Plan (No. 201907069).

Disclosure statement

The authors declare that there are no conflicts of interest.

Data availability

The dataset(s) supporting the conclusions of this article is(are) included within the article.

References

  • [1].Rougier P, Andre T, Panis Y, et al. Colon cancer. Gastroentérologie Clinique et Biologique. 2006;30(2):2s24-s2s9. [PubMed] [Google Scholar]
  • [2].Rhode H, Liehr T, Kosyakova N, et al. Molecular cytogenetic characterization of two murine colorectal cancer cell lines. OBM Gene. 2018;2(3):1. [Google Scholar]
  • [3].Gu M-J, Huang Q-C, Bao C-Z, et al. Attributable causes of colorectal cancer in China. BMC Cancer. 2018;18(1):38. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • [4].Zhang Y, Chen Z, Li J.. The current status of treatment for colorectal cancer in China: a systematic review. Medicine (Baltimore). 2017;96(40):e8242. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • [5].Ebbesen KK, Hansen TB, Kjems J. Insights into circular RNA biology. RNA Biol. 2017;14(8):1035–1045. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • [6].Zeng K, Chen X, Xu M, et al. CircHIPK3 promotes colorectal cancer growth and metastasis by sponging miR-7. Cell Death Dis. 2018;9(4):417. [DOI] [PMC free article] [PubMed] [Google Scholar] [Retracted]
  • [7].Wang X, Zhang Y, Huang L, et al. Decreased expression of hsa_circ_001988 in colorectal cancer and its clinical significances.. Int J Clin Exp Pathol. 2015;8(12):16020–16025. [PMC free article] [PubMed] [Google Scholar]
  • [8].Weng W, Wei Q, Toden S, et al. Circular RNA ciRS-7—a promising prognostic biomarker and a potential therapeutic target in colorectal cancer. Clin Cancer Res off J Am Assoc Cancer Res. 2017;23(14):3918–3928. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • [9].Xu H, Wang C, Song H, et al. RNA-Seq profiling of circular RNAs in human colorectal cancer liver metastasis and the potential biomarkers. Mol Cancer. 2019;18(1):8. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • [10].Li Z, Zhou Y, Yang G, et al. Using circular RNA SMARCA5 as a potential novel biomarker for hepatocellular carcinoma. Clin Chim Acta. 2019;492:37–44. [DOI] [PubMed] [Google Scholar]
  • [11].Kong Z, Wan X, Zhang Y, et al. Androgen-responsive circular RNA circSMARCA5 is up-regulated and promotes cell proliferation in prostate cancer. Biochem Biophys Res Commun. 2017;493(3):1217–1223. [DOI] [PubMed] [Google Scholar]
  • [12].Yu J, Xu Q-G, Wang Z-G, et al. Circular RNA cSMARCA5 inhibits growth and metastasis in hepatocellular carcinoma. J Hepatol. 2018;68(6):1214–1227. [DOI] [PubMed] [Google Scholar]
  • [13].Wang Y, Li H, Lu H, et al. <p>Circular RNA SMARCA5 inhibits the proliferation, migration, and invasion of non-small cell lung cancer by miR-19b-3p/HOXA9 axis. <![cdata[oncotargets and Therapy]]>. 2019;12:7055–7065. [DOI] [PMC free article] [PubMed] [Google Scholar] [Retracted]
  • [14].Livak KJ, Schmittgen TD. Analysis of relative gene expression data using real-time quantitative PCR and the 2−ΔΔCT method. methods. 2001;25(4):402–408. [DOI] [PubMed] [Google Scholar]
  • [15].Liu H, Wu Y, Wang S, et al. Circ-SMARCA5 suppresses progression of multiple myeloma by targeting miR-767–5p. BMC Cancer. 2019;19(1):937. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • [16].Cao J, Yan X-R, Liu T, et al. MicroRNA-552 promotes tumor cell proliferation and migration by directly targeting DACH1 via the Wnt/β-catenin signaling pathway in colorectal cancer. Oncol Lett. 2017;14(3):3795–3802. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • [17].Tian -J-JDC, Liang L. Involvement of circular RNA SMARCA5/microRNA-620 axis in the regulation of cervical cancer cell proliferation, invasion and migration.. Eur Rev Med Pharmacol Sci. 2018;22(24):8589–8598. [DOI] [PubMed] [Google Scholar]
  • [18].Barbagallo D, Caponnetto A, Cirnigliaro M, et al. CircSMARCA5 inhibits migration of glioblastoma multiforme cells by regulating a molecular axis involving splicing factors SRSF1/SRSF3/PTB. Int J Mol Sci. 2018;19(2):480. . [DOI] [PMC free article] [PubMed] [Google Scholar]
  • [19].Wang Y, Li H, Lu H, et al. Circular RNA SMARCA5 inhibits the proliferation, migration, and invasion of non-small cell lung cancer by miR-19b-3p/HOXA9 axis. Onco Targets Ther. 2006;30:24–29. [DOI] [PMC free article] [PubMed] [Google Scholar] [Retracted]
  • [20].Dudekula DB, Panda AC, Grammatikakis I, et al. CircInteractome: a web tool for exploring circular RNAs and their interacting proteins and microRNAs. RNA Biol. 2016;13(1):34–42. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • [21].Cai W, Xu Y, Yin J, et al. miR-552–5p facilitates osteosarcoma cell proliferation and metastasis by targeting WIF1.. Exp Ther Med. 2019;17(5):3781–3788. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • [22].Wang N, Liu W. Increased expression of miR-552 acts as a potential predictor biomarker for poor prognosis of colorectal cancer.. Eur Rev Med Pharmacol Sci. 2018;22(2):412–416. [DOI] [PubMed] [Google Scholar]
  • [23].Sebio A, Kahn M, Lenz H-J. The potential of targeting Wnt/β-catenin in colon cancer. Expert Opin Ther Targets. 2014;18(6):611–615. [DOI] [PubMed] [Google Scholar]
  • [24].Ahmad R, Kumar B, Chen Z, et al. Loss of claudin-3 expression induces IL6/gp130/Stat3 signaling to promote colon cancer malignancy by hyperactivating Wnt/β-catenin signaling. Oncogene. 2017;36(47):6592–6604. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • [25].Voloshanenko O, Erdmann G, Dubash TD, et al. Wnt secretion is required to maintain high levels of Wnt activity in colon cancer cells. Nat Commun. 2013;4(1):2610. . [DOI] [PMC free article] [PubMed] [Google Scholar]
  • [26].Shibata M, Ham K, Hoque MO. A time for YAP1: tumorigenesis, immunosuppression and targeted therapy. Int J Cancer. 2018;143(9):2133–2144. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • [27].Cho SY, Gwak JW, Shin YC, et al. Expression of Hippo pathway genes and their clinical significance in colon adenocarcinoma.. Oncol Lett. 2018;15(4):4926–4936. . [DOI] [PMC free article] [PubMed] [Google Scholar]
  • [28].Wang L, Shi S, Guo Z, et al. Overexpression of YAP and TAZ is an independent predictor of prognosis in colorectal cancer and related to the proliferation and metastasis of colon cancer cells. PloS One. 2013;8(6):e65539. [DOI] [PMC free article] [PubMed] [Google Scholar] [Retracted]

Associated Data

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

Data Availability Statement

The dataset(s) supporting the conclusions of this article is(are) included within the article.

Articles from Cell Cycle are provided here courtesy of Taylor & Francis

RESOURCES