The Effect of miR-4800 Restoration on Proliferation and Migration of Human Breast Cancer Cells In Vitro

Purpose: MicroRNAs (miRNAs) can contribute to cancer initiation, development, and progression. In this study, the effect of miRNA-4800 restoration on the growth and migration inhibition of human breast cancer (BC) cells was investigated. Methods: For this purpose, transfection of miR-4800 was performed into MDA-MB-231 BC cells using jetPEI. Subsequently, the expression levels of miR-4800 and CXCR4, ROCK1, CD44, and vimentin genes were measured using quantitative real-time polymerase chain reaction (q-RT-PCR) and specific primers. Also, the proliferation inhibition and apoptosis induction of cancer cells were evaluated by MTT and flow cytometry (Annexin V-PI method) techniques, respectively. Additionally, cancer cell migration after miR-4800 transfection was assessed by wound-healing (scratch) assay. Results: The restoration of miR-4800 in MDA-MB-231 cells resulted in the decreased expression level of CXCR4 (P ˂ 0.01), ROCK1 (P ˂ 0.0001), CD44 (P ˂ 0.0001), and vimentin (P ˂ 0.0001) genes. Also, MTT results showed restoration of miR-4800 could significantly reduce cell viability rate (P ˂ 0.0001) compared with the control group. Cell migration remarkably inhibited (P ˂ 0.001) upon miR-4800 transfection in treated BC cells. Flow cytometry data demonstrated that miR-4800 replacement considerably induced apoptosis in cancer cells (P ˂ 0.001) compared with control cells. Conclusion: Taken together, it seems that miR-4800 can act as a tumor suppressor miRNA in BC and play an essential role in modulating apoptosis, migration, and metastasis in BC. Therefore, it may be suggested as a potential therapeutic target in treating BC by performing additional tests in the future

mir-451a-5p Modulates Breast Cancer Cell Apoptosis, Migration, and Chemosensitivity to Carboplatin through the PTEN Pathway

Background: MicroRNAs (miRNAs) can play essential roles in the modulation of cancer cell growth, survival, and resistance to chemotherapy. Thus, we hypothesized that restoration of miR-451a-5p (a tumor suppressor) might affect sensitivity to chemotherapeutics in breast cancer cells. Methods: For this purpose, malignant breast cancer cells (MDA-MB-231) were transfected with miR-451a-5p mimic and exposed with carboplatin. Then, the apoptotic rate was evaluated by flow cytometry and DAPI staining (apoptosis), q-RT-PCR (expression levels of caspase-3, caspase-8, MMP9, ROCK, vimentin, c-Myc genes). Moreover, the proliferation and migration of cancer cells were assessed by MTT (cell viability) and wound healing assay. The western blot assay was used for protein expression of PTEN, AKT, and P-AKT. Results: Our findings demonstrated that a combination of miR-451a-5p restoration with carboplatin administration could additionally induce apoptosis, repress the proliferation and migration, and also increase PTEN protein expression with no significant alteration on the AKT/P-AKT protein expressions in the breast cancer cells. The present data was analyzed using GraphPad Prism 6 software by non-parametric one-way ANOVA and t-test. Conclusion: In conclusion, it seems that overexpression of miR-451a can enhance the chemosensitivity of breast cancer cells to carboplatin therapy. Thus, it may shed new light on miR-451a management of breast cancer chemoresistance and may be a beneficial strategy for future cancer therapy. However, further studies, particularly in other signaling pathways, should be required