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. 2014 May 21;105(7):875–882. doi: 10.1111/cas.12426

Retracted: Glabridin attenuates the migratory and invasive capacity of breast cancer cells by activating microRNA-200c

Xianqing Ye 1,1, Fei Jiang 1,1, Yuan Li 1,1, Juan Mu 1, Lu Si 1, Xingxing Wang 1, Shilong Ning 1, Zhong Li 1
PMCID: PMC4317926  PMID: 24754877

Abstract

Current treatments for breast cancer, a common malignancy in human females, are less than satisfactory because of high rates of metastasis. Glabridin (GLA), which acts through the FAK/ROS signaling pathway, has been used as an antioxidant and anti-metastatic agent. However, little is known regarding the effect of microRNA (miRNA) on GLA's anti-metastatic activity. The miRNA-200 family, which is frequently expressed at low levels in triple negative breast cancers, inhibits metastasis by blocking the epithelial–mesenchymal transition. Here, we found that GLA attenuated the migratory and invasive capacity of breast cancer cells by activating miR-200c. GLA induced the mesenchymal–epithelial transition in vitro and in vivo, as determined by increased expression of the epithelial marker, E-cadherin, and decreased expression of the mesenchymal marker, vimentin. Overexpression of miR-200c enhanced the expression of E-cadherin and decreased the expression of vimentin. Furthermore, in MDA-MB-231 and BT-549 breast cancer cells exposed to GLA, knockdown of miR-200c blocked the GLA-induced mesenchymal–epithelial transition and alleviated the GLA-induced inhibition of migration and invasion. Thus, elevation of miR-200c by GLA has considerable therapeutic potential for anti-metastatic therapy for breast cancer patients.

Keywords: Breast cancer, epithelial-mesenchymal transition, glabridin, metastasis, microRNA-200c

Breast cancer is the leading cancer for women, in terms of incidence and mortality.(1) Metastasis of breast cancer cells to bone, lungs and other vital organs is responsible for most cancer deaths.(2) Current treatments for breast cancer, surgical resection and chemotherapy, are less than satisfactory because of high recurrence rates.(3) Many efforts have been made to identify molecular factors correlating with the prognosis of breast cancer patients; however, the mechanisms underlying metastasis and recurrence remain obscure. A continued search for molecular markers that predict metastasis and recurrence of breast cancer is essential.

The root of Glycyrrhiza glabra (licorice) has been used for many centuries in Asia and Europe as an antioxidant, an antidote, an demulcent and an expectorant, and as a remedy for allergic inflammation, as well as a flavoring and sweetening agent.(4) Glabridin (GLA), an active isoflavan in the hydrophobic fraction of licorice root,(5) is readily incorporated into gut cells of humans and mice and released on the basolateral side as the aglycone form.(6) GLA has antifungal, antibacterial, antiatherosclerotic, antiosteoporosis, immunomodulatory, antioxidative and antiobesity activities.(7,8) GLA inhibits growth of many human cancers(9) and enhances the efficacy of cancer chemotherapy by inhibiting synthesis of P-glycoprotein and multidrug resistance protein 1.(10) Nevertheless, the antitumorigenic mechanisms of GLA in cancer migration and invasion remain largely unknown.

MicroRNA (miRNA), small noncoding RNA molecules of 21–23 nucleotides, have the capacity to inhibit translation or induce mRNA degradation, predominantly through targeting of the 3′-untranslated regions of mRNA.(11) Abnormal expression of miRNA is associated with a variety of human cancers. Some miRNA, such as miR-21, miR-372 and miR-373, which are overexpressed in a variety of malignancies and are implicated in various malignancy-related processes, including cell proliferation, invasion and metastasis, may function as oncogenes.(12,13) Others, such as let-7, miR-124 and the miR-200 family (miR-200s) have decreased expression in cancers, and may function as tumor suppressors by regulating RAS, Bcl-2 and the epithelial–mesenchymal transition (EMT).(14–16)

Epithelial–mesenchymal transition is a developmental process by which epithelial cells are converted to mesenchymal cells during embryogenesis, tissue remodeling and wound healing.(17) During these processes, epithelial cells acquire properties of mesenchymal cells and show reduced intercellular adhesion and increased invasive capacity.(18) Activation of the EMT has been implicated in the metastasis of various human tumors, including breast cancers(18) Here, we found that GLA reduced the migratory and invasive capacities of breast cancer cells. In human breast cancer cells, GLA upregulated the expression of miR-200c, which blocked the EMT process in vitro and in vivo. These results indicate that GLA is likely to be a new drug for treatment of breast cancer.

Materials and Methods

Cell culture

Human breast cancer cell lines, MDA-MB-231 and BT-549, were obtained from the American Type Culture Collection (ATCC, Rockville, MD, USA) and were maintained according to the ATCC's recommendation. MDA-MB-231 cells were maintained in L-15 medium; BT-549 cells were routinely maintained in RPMI-1640 medium (Life Technologies/Gibco, Grand Island, NY, USA). Both media were supplemented with 10% FBS (Life Technologies/Gibco), 100 U/mL penicillin and 100 mg/mL streptomycin (Life Technologies/Gibco, Gaithersburg, MD, USA). BT-549 cells were incubated at 37°C in 5% CO2; MDA-MB-231 cells were grown in the absence of CO2. GLA (99.0% purity) was purchased from Sigma Chemical (St. Louis, MO, USA).

Animals

This study was performed according to a protocol approved by the Nanjing Medical University Institutional Animal Care and Use Committee (Approval ID 20130234), and animals were treated humanely and with regard for alleviation of suffering. Briefly, 1 × 107 cells were injected s.c. into the right armpit of nude BALB/c mice (six mice per group). One month later, GLA (0 or 20 mg/kg·BW) in 100 μL of corn oil was administered by gavage each day for another 5 weeks. The tumor tissues were then removed for investigation.

Determination of cell vitality

MDA-MB-231 and BT-549 cells (2 × 104) were seeded in 96-well plates for 24 h. At that time, cells were exposed to 0.0, 5.0, 10.0 or 20.0 μM GLA for 4 days. Then, they were incubated with 20 μL of Cell Counting Kit-8 (CCK-8 [Dojindo Molecular Technologies, Kumamoto, Japan]) assay solution for 4 h. The absorbance at 450 nm was measured with a multi-well plate reader (Model 680; Bio-Rad, Hercules, CA, USA). Non-treated cells were used as controls.

Wound healing assay

After the MDA-MB-231 and BT-549 cells were exposed to 0.0, 5.0, 10.0 or 20.0 μM GLA for 4 days, they were wounded by manual scraping four times with a pipette tip (volume 1000 μL; diameter at the tip 1 mm). After the cells were washed, they were exposed to 0.0, 5.0, 10.0 or 20.0 μM GLA for another 24 h. The cells were then observed under a microscope (Olympus, Tokyo, Japan). The migration rate was determined using the following equation:

graphic file with name cas0105-0875-m1.jpg

Transwell assays

Transwell assays were performed with growth factor-reduced Matrigel-coated filters (8-mm pore size [BD, Franklin Lakes, NJ]) in 24-well plates. Cells were trypsinized and seeded onto the upper chambers of the transwells (3 × 104 cells/well) in supplement-free medium. The lower chambers of the transwells were filled with medium containing 100 ng/mL of epidermal growth factor (EGF, R&D Systems, Minneapolis, MN, USA). The chambers were incubated at 37°C for 24 h. At the end of incubation, cells on the upper surface of the filter were removed with a cotton swab. Cells migrating through the filter to the lower surface were fixed with 4% paraformaldehyde for 10 min and stained with 0.1% crystal violet for 5 min. Migrated cells were viewed and photographed under a phase-contrast microscope (Olympus) and counted in five randomly chosen fields.

Western blots

Cell lysates were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and transferred to polyvinylidene fluoride membranes (Millipore, Billerica, MA, USA); the immune complexes were detected by enhanced chemiluminescence. Antibodies used were those for E-cadherin and vimentin (Cell Signaling Technology, Beverly, MA, USA) and GAPDH (Sigma Chemical). Blots were normalized by use of GAPDH to correct for differences in loading of the proteins. For densitometric analyses, the bands on the blots were measured using an Eagle Eye II imaging system.

RT-PCR

Total cellular RNA was isolated with Trizol (Invitrogen, Carlsbad, CA, USA) according to the manufacturer's recommendations. Then total RNA (2 μg) was transcribed into cDNA using AMV Reverse Transcriptase (Promega, Madison, WI, USA). Primers for E-cadherin –F: 5′-TGCTCACATTTCCCAACTC-3′ and E-cadherin –R: 5′-TCTGTCACCTTCAGCCATC-3′ and vimentin –F: 5′- CCAGGCAAAGCAGGAGTC-3′, vimentin –R: 5′-GGGTATCAACCAGAGGGAGT-3′ were used for PCR amplification. The PCR reaction was evaluated by checking the products on 2% w/v agarose gels. Bands were normalized by use of GAPDH to correct for differences in loading of the cDNA. For densitometric analyses, the bands on the blots were measured using the Eagle Eye II imaging system.

Quantitative real-time polymerase chain reaction

For detection of E-cadherin, total RNA (2 μg) was transcribed into cDNA using AMV Reverse Transcriptase (Promega). Primers used were as described above. Quantitative RT-PCR (qRT-PCR) was performed with the Applied Biosystems 7300 HT machine and Maxima SYBR Green/ROX qPCR Master Mix (Fermentas, Waltham, MA, USA). The PCR reaction was evaluated by melting curve analysis. GAPDH was amplified to ensure cDNA integrity and to normalize expression. For detection of mature miR-200s, 2 μg of total RNA, miRNA-specific stem-loop RT primers and MMLV reverse transcriptase (Promega) were used in reverse transcription following the manufacturer's protocol. The RT primers for miR-200s and U6 small nuclear RNA were designed by RiboBio (Guangzhou, China). qRT-PCR was performed using the Power SYBR Green Master Mix (Applied Biosystems, Foster City, CA, USA) and an ABI 7300 realtime PCR detection system (Applied Biosystems). Forward and reverse primers were designed by RiboBio. The U6 snRNA was used as an internal control. Fold changes in expression of each gene were calculated using a comparative threshold cycle (Ct) method with the formula Inline graphic.

Cell transfection

miR-200c-mimics, miR-200c-inhibitor and miRNA-NC (negative control) mimics and inhibitor were synthesized by RiBoBio. Cells were transiently transfected by use of the Lipofectamine 2000 reagent (Invitrogen) for 12 h, according to the manufacturer's protocol.

Statistical analysis

Derived values were presented as the means ± SD. A Student's t-test, and a one-way anova followed by Dunnett's t-test were used to assess significant differences between groups. P-values <0.05 were considered statistically significant.

Results

Glabridin reduces the migratory and invasive capacities of breast cancer cells

Glabridin (GLA) did not appreciably affect the vitality of MDA-MB-231 or BT-549 breast cancer cells at concentrations of 0.0, 5.0, 10.0 or 20.0 μM (Fig. 1a). To determine the effects of GLA on the motility of breast cancer cells, wound healing assays were performed. MDA-MB-231 and BT-549 cells displayed high motility, but GLA reduced such capability in a dose-dependent manner (Fig. 1b). Because 10.0 μM GLA effectively decreased the motility of these cells, this concentration was selected for further investigations. As determined with transwell assays, GLA decreased both the migratory and invasive capacities of MDA-MB-231 and BT-549 cells (Fig. 2a–c).

Figure 1.

Figure 1

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Glabridin (GLA) inhibits the migratory capacity of human breast cancer cells. (a) Effects of GLA on the viability of breast cancer cells. MDA-MB-231 and BT-549 breast cancer cells were exposed to 0.0, 5.0, 10.0 or 20.0 μM GLA for 4 days. Their viability was measured by use of a Cell Counting Kit-8 assay. The relative folds of cell viability were determined by comparing growth of cells not exposed to GLA. (b) Cells were exposed to 0.0, 5.0, 10.0 or 20.0 μM GLA for 4 days. After the cells were wounded, they were exposed to the same concentrations of GLA for another 24 h. GLA attenuated the migratory capacity of MDA-MB-231 (top) and BT-549 (bottom) cells, as determined by scratch wound-healing assays. (c) Relative levels of cell migration.

Figure 2.

Figure 2

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Glabridin (GLA) attenuates the invasive capacities of MDA-MB-231 and BT-549 cells. The migratory and invasive capacities of MDA-MB-231 and BT-549 cells were quantified by 24-well cell migration assays and by use of the BD Matrigel tumor invasion system. Cells were exposed to 0.0, 5.0, 10.0, or 20.0 μM GLA for 48 h. Epidermal growth factor (EGF) functioned as a chemoattractant for cancer migration and invasion. GLA reduced the migratory and invasive capacities of (a, top) MDA-MB-231 and (a, bottom) BT-549 cells. (b) Numbers of migrating/invading MDA-MB-231 cells treated with GLA. (c) Numbers of migrating/invading BT-549 cells treated with GLA (mean ± SD, n = 5).

Glabridin induces the mesenchymal–epithelial transition in human breast cancer cells

Because the EMT enables cells to move and invade,(17,18) the effects of GLA on this process were determined for breast cancer cells. MDA-MB-231 cells displayed a fibroblast-like mesenchymal appearance; however, after these cells were exposed to 10.0 μM GLA for 4 days, they showed an epithelial-like morphology (Fig. 3a). Moreover, in MDA-MB-231 cells, GLA enhanced the expression of E-cadherin mRNA and decreased the expression of vimentin mRNA, indicating transcriptional regulation (Fig. 3b,c). Furthermore, MDA-MB-231 cells were exposed to 10.0 μM GLA for different times, and the effects of GLA on the expressions of EMT/adhesive markers, E-cadherin and vimentin, were determined over 0–48 h. GLA elevated the E-cadherin levels but reduced the vimentin levels (Fig. 3d,e). For BT-549 cells, increasing concentrations of GLA elevated E-cadherin levels but decreased the expression of vimentin (Fig. 3f,g).

Figure 3.

Figure 3

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Effects of glabridin (GLA) on the epithelial–mesenchymal transition (EMT) markers in MDA-MB-231 and BT-549 cells. (a) Morphological images of MDA-MB-231 cells exposed to 0 or 10 μM GLA for 4 days. (b) MDA-MB-231 cells were exposed to 0, 10 or 20 μM GLA for 2 days. RT-PCR analyses and (c) relative mRNA levels of E-cadherin and vimentin were determined (mean ± SD, n = 3). MDA-MB-231 cells were exposed to 10 μM GLA for 0, 8, 16, 24 or 48 h. Western blot analyses (d) and relative protein levels (e) of E-cadherin and vimentin (mean ± SD, n = 3). BT-549 cells were exposed to 0, 1, 5, 10 or 20 μM GLA for 48 h. (f) Western blot analyses and (g) relative protein levels of E-cadherin and vimentin (mean ± SD, n = 3).

Glabridin promotes expression of epithelial properties and attenuates the mesenchymal phenotype in vivo

MDA-MB-231 cells were injected s.c. into the right armpit of nude BALB/c mice. After 4 weeks, GLA (0 or 20 mg/kg·BW) in 100 μL corn oil was administered by gavage every day for another 5 weeks. Then, the tumor tissues were removed and used for RT-PCR, qRT-PCR and western blots. In tumors formed by these cells, GLA elevated expression of E-cadherin mRNA but decreased expression of vimentin mRNA (Fig. 4a,b). Western blots confirmed this observation; GLA enhanced E-cadherin protein expression but attenuated the expression of vimentin (Fig. 4c).

Figure 4.

Figure 4

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Effects of glabridin (GLA) on epithelial–mesenchymal transition markers and miR-200s in MDA-MB-231 breast cancer xenografts. Nude mice bearing breast cancers were treated with the vehicle or with GLA (20 mg/kg/d). (a, top) RT-PCR analyses and (b) relative mRNA levels of E-cadherin and vimentin (mean ± SD, n = 3). (a, bottom) Western blot analyses and (c) relative protein levels of E-cadherin and vimentin (mean ± SD, n = 3). (d) Quantitative RT-PCR analysis of miR-200a, miR-200b, miR-200c, miR-141 and miR-429. Con, control. **P < 0.01 compared with medium control MDA-MB-231 cells.

Glabridin upregulates the expression of miR-200s in vitro and in vivo

miR-200s are involved in regulating the EMT and cancer cell invasion through inhibition of the E-cadherin transcriptional repressors, ZEB1/2.(18) Here, in MDA-MB-231 cells exposed to GLA, there were increased expressions of miR-200a, miR-200c and miR-141 (Fig. 5a). For BT-549 cells, GLA elevated all miR-200s tested, except miR-429 (Fig. 5b). For both types of cells, GLA upregulated the expression of miR-200c more extensively. Moreover, GLA elevated the expressions of miR-200a, miR-200b, miR-200c, miR-141 and miR-429 in tumors formed by MDA-MB-231 cells (Fig. 4d).

Figure 5.

Figure 5

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Glabridin (GLA) enhances the expression of miR-200s in MDA-MB-231 and BT-549 cells. MDA-MB-231 (a) and BT-549 (b) cells were exposed to 10 μM GLA for 48 h. Quantitative RT-PCR analysis of their miR-200a, miR-200b, miR-200c, miR-141 and miR-429. *P < 0.05 and **P < 0.01 compared with medium control MDA-MB-231 and BT-549 cells.

Glabridin induces the mesenchymal–epithelial transition in MDA-MB-231 cells through miR-200c

miR-200c is involved in regulating the EMT.(17) After transfection by con-mimic or miR-200c-mimic for 12 h, overexpression of miR-200c (Fig. 6a) enhanced the expression of E-cadherin in MDA-MB-231 cells (Fig. 6b), which showed an epithelial-like morphology (Fig. 6c). The functions of miR-200c in GLA-mediated mesenchymal–epithelial transition (MET) were determined. After MDA-MB-231 and BT-549 cells were transfected by anti-con or anti-miR-200c for 12 h, they were exposed to 0.0 or 10.0 μM GLA for 2 days. Knockdown of miR-200c reduced the GLA-induced increased expression of E-cadherin (Fig. 6d,e). Meanwhile, knockdown of miR-200a mildly reduced the GLA-induced increased expression of E-cadherin (Fig. S1a,b).

Figure 6.

Figure 6

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miR-200c is involved in expression of epithelial–mesenchymal transition markers in glabridin (GLA)-treated human breast cancer cells. After MDA-MB-231cells were transfected by con-mimic or miR-200c-mimic for 12 h. (a) quantitative RT-PCR analysis of mir-200c, (b) western blot analyses of E-cadherin and (c) morphological images of MDA-MB-231 cells exposed to con-mimic or miR-200c-mimic. After MDA-MB-231 and BT-549 cells were transfected with anti-con or anti-miR-200c for 12 h, they were exposed to 0 or 10 μM GLA for 48 h. (d) Western blot analyses and (e) relative protein levels of E-cadherin (mean ± SD, n = 3). **P < 0.01 compared with medium control MDA-MB-231 or BT-549 cells, ##P < 0.01 compared with anti-con-transfected MDA-MB-231 or BT-549cells cells exposed to 10 μM GLA.

Glabridin attenuates the migratory and invasive capacities of breast cancer cells through miR-200c

Finally, the function of miR-200c in GLA-induced inhibition of migratory and invasive capacities in breast cancer cells was determined. GLA attenuated the migratory and invasive capacities of MDA-MB-231 (Fig. 7a,b) and BT-549 (Fig. 7a,c) cells; however, knockdown of miR-200c and miR-200a, specifically miR-200c, reversed such phenomena (Fig. S2).

Figure 7.

Figure 7

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Glabridin (GLA) attenuates the migratory and invasive capacities of MDA-MB-231 and BT-549 cells through miR-200c. After cells were transfected by anti-con or anti-miR-200c for 12 h, they were exposed to 0 or 10 μM GLA for 48 h. (a) Transwell analyses and numbers of migratory/invasive MDA-MB-231 (b) and BT-549 (c) cells (mean ± SD, n = 5). **P < 0.01 compared with medium control MDA-MB-231 or BT-549 cells, and ##P < 0.01 compared with anti-con-transfected MDA-MB-231 or BT-549 cells exposed to 10 μM GLA.

Discussion

Breast cancer is the most commonly diagnosed malignancy among women.(1) Although the mortality rate for breast cancer has improved, it remains a deadly cancer, with mortality largely attributed to metastatic disease.(1,19) Cytotoxic chemotherapies such as taxanes are initially effective in most patients with metastatic triple negative breast cancers (TNBC), but most of these tumors recur after chemotherapy.(19) Metastatic tumor relapses are characterized by rapidly proliferating, drug-resistant cancers and are associated with a high mortality rate.(20) Metastasis is a complicated process, during which cells undergo phenotypic changes to migrate away from the primary tumor, survive in the vasculature or lymphatics, and colonize metastatic sites.(21,22)

As demonstrated in the present study, a compound derived from licorice inhibits migration and invasion of human breast cancer cells. This effect was noted for GLA, a main functional component in licorice root. GLA exhibits multiple pharmacological activities on melanogenesis, inflammation and oxidative stress.(7,8) It also inhibits oxidation of low-density lipoproteins and reduces fatigue.(23,24) A GLA-rich carbon dioxide extract of licorice has anti-obesity effects in obese mice.(8) Although, in lung cancer and breast cancer cells GLA inhibits migration and invasion concomitant with inhibition of the integrin/FAK pathway,(25,26) there has been no evidence that GLA is related to the beneficial effects on inhibition of human breast cancers via the EMT. Here, we found that GLA attenuates the migration and invasion of breast cancer cells by inhibition of the EMT.

As a morphogenic program, the EMT is involved in the formation of tissue and organs during embryonic development and wound healing.(12) Furthermore, EMT contributes to the progression of early-stage tumors to invasive malignancies.(15,16) Here, we report that MDA-MB-231 cells exposed to GLA for 4 days show an epithelial-like morphology. Furthermore, there is increased expression of E-cadherin and decreased expression of vimentin. After MDA-MB-231 cells were injected into nude BALB/c mice, administration of GLA enhanced E-cadherin expression and attenuated vimentin expression in tumors formed by these cells. These results demonstrate that, with exposure to GLA, MDA-MB-231 cells undergo a MET in vitro and in vivo.

MicroRNA are small (18–25 nucleotide) non-coding RNA that regulate gene expression post-transcriptionally by binding to the 3′ untranslated region of the target mRNA and inhibiting translation or targeting the mRNA for degradation.(14,15) The miR-200s are comprised of two polycistronic clusters: miR-200c and miR-141 on chromosome 12, and miR-200a, miR-200b and miR-429 on chromosome 1.(27) The miR-200 family is highly expressed in breast epithelial cells and luminal-like carcinomas but is lost in the more aggressive TNBC.(27) These miRNA serve to maintain an epithelial phenotype and protect against EMT through repression of multiple targets, including the EMT-inducing transcription factors (ZEB1 and ZEB2); genes involved in migration (FN1, MSN and WAVE3); and epigenetic regulators (SIRT1 and Suz12).(28,29) Here, in MDA-MB-231 and BT-549 cells, as well as in tumor tissues, GLA upregulates the expression of miR-200c. However, the molecular mechanisms underlying the activation of miR-200c by GLA remain unclear.

Wild type p53 is an upstream factor that transcriptionally regulates the expression of miR-200c.(30) However, the MDA-MB-231 and BT-549 cells are p53 mutated cell lines, so in these cells, the upstream regulator of miR-200c might not be p53. Previous studies have demonstrated the relationships among FAK/Rho signaling, p53 and the miR-200 family. On one hand, in p53 wild type cells, FAK localizes to the nucleus and binds directly to p53 to inhibit its function;(31) moreover, FAK binds to Mdm-2 and coordinates ubiquitination of p53 to cause p53 degradation.(32) On the other hand, in p53 mutated cells, activation of FAK/Rho upregulates the PI-3-kinase and Akt, which inhibits miR-200s and causes a mesenchymal phenotype.(33,34) Importantly, previous study suggests that glabridin inhibits the migration, invasion and angiogenesis of MDA-MB-231 cells by inhibiting FAK/Rho signaling pathway.(25) Thus, FAK/Rho signaling could be the upstream regulator of miR-200c in glabridin-treated MDA-MB-231 and BT-549 cells.

Furthermore, we determined the effects of GLA on the expression of miR-205, miR-101, miR-192 and miR-9 (the metastasis related miRNA in breast cancer,(35,36) in vitro and in vivo, and found that, compared to miR-200c and miR-205, there were no detectable effects of GLA on the expressions of miR-101, miR-192 and miR-9 (Fig. S2). Although GLA also upregulated the expression of miR-205, a recent report found that miR-205 levels are highly variable across both tumor types and do not relate to E-cadherin expression.(37) These data suggested the specificity of miR-200 family in GLA-induced cellular response.

In conclusion, GLA upregulates miR-200c expression in MDA-MB-231 and BT-549 breast cancer cells. This process induces an EMT, as determined by the increased expression of E-cadherin and decreased expression of vimentin. As a result, GLA attenuates the migratory and invasive capacities in vitro and in vivo. By identifying a mechanism whereby GLA regulates EMT through activation of miR-200c, our results expand understanding of the anti-metastatic potential of GLA.

Acknowledgments

The authors wish to thank Donald L. Hill (University of Alabama at Birmingham, USA) for editing the present paper. This work was supported by the National Natural Science Foundation of China (81171987, 30972507), the Research Fund for the Doctoral Program of Higher Education of China (20133234110007), and a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD). The funders had no role in the study design, the data collection and analysis, the decision to publish or the preparation of the manuscript.

Disclosure Statement

The authors have no conflict of interest.

Supporting Information

Additional supporting information may be found in the online version of this article:

Fig. S1. Functions of miR-200a in glabridin (GLA)-induced attenuation of the invasive capacities in MDA-MB-231 cells.

Fig. S2. Effects of glabridin (GLA) on the expressions of miR-205, miR-101, miR-192 and miR-9 in vitro and in vivo.

cas0105-0875-sd1.pdf (276.6KB, pdf)

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Associated Data

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

Supplementary Materials

Fig. S1. Functions of miR-200a in glabridin (GLA)-induced attenuation of the invasive capacities in MDA-MB-231 cells.

Fig. S2. Effects of glabridin (GLA) on the expressions of miR-205, miR-101, miR-192 and miR-9 in vitro and in vivo.

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