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MiR-93 suppresses tumorigenesis and enhances chemosensitivity of breast cancer via dual targeting E2F1 and CCND1.

ABSTRACT: Chemoresistance of tumors often leads to treatment failure in clinical practice, which underscores pivotal needs to uncover novel therapeutic strategies. Accumulating evidences show that microRNAs (miRNAs) are widely involved in carcinogenesis, but their function on chemoresistance remains largely unexplored. In this study, we found that miR-93-5p (miR-93) significantly inhibited cell proliferation, induced G1/S cell cycle arrest and increased chemosensitivity to paclitaxel (PTX) in vitro and in vivo. Moreover, two well-established oncogenes, E2F1 and CCND1, were identified as dual targets of miR-93. Knockdown of E2F1 and CCND1 reduced cell proliferation and PTX-sensitivity, whereas overexpression of them had the opposite effect. More importantly, overexpression of E2F1 and CCND1 antagonized miR-93-mediated cell cycle arrest and apoptosis. Further mechanistic study revealed that miR-93 exhibited its inhibitory role by directly targeting E2F1 and CCND1 to inactivate pRB/E2F1 pathway and AKT phosphorylation. Taken together, our findings suggested that miR-93 greatly improved chemosensitivity and potentially served as a novel therapeutic target for breast cancer treatment.

SUBMITTER: Bao C

PROVIDER: S-EPMC7428045 | biostudies-literature | 2020 Aug

REPOSITORIES: biostudies-literature

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MiR-93 suppresses tumorigenesis and enhances chemosensitivity of breast cancer via dual targeting E2F1 and CCND1.

Bao Chang C Chen Jishun J Chen Danni D Lu Yunkun Y Lou Weiyang W Ding Bisha B Xu Liang L Fan Weimin W

Cell death & disease 20200814 8

Chemoresistance of tumors often leads to treatment failure in clinical practice, which underscores pivotal needs to uncover novel therapeutic strategies. Accumulating evidences show that microRNAs (miRNAs) are widely involved in carcinogenesis, but their function on chemoresistance remains largely unexplored. In this study, we found that miR-93-5p (miR-93) significantly inhibited cell proliferation, induced G1/S cell cycle arrest and increased chemosensitivity to paclitaxel (PTX) in vitro and in ...[more]

PMID: 32796817

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Project description:Background:Lacrimal adenoid cystic carcinoma (LACC) is one of the most common malignancies that affects lacrimal gland. MicroRNAs are known to play a crucial role as oncogenes or tumor suppressors. Specifically, miR-93 has been reported to play a crucial role in colorectal, breast, pancreatic, lung cancer and hepatocellular carcinoma. However, the role of miR-93 in LACC and the potential molecular mechanisms involved remain unknown. Therefore, we took the challenge to determine the involvement of miR-93 in the LACC by targeting BRMS1L. Method:A total of 5 adenoid cystic carcinoma (ACC) of lacrimal gland patient tissues and their plasma were examined. Three normal lacrimal glands and three normal serums were collected as a control group. After surgical resection, the specimens were preserved in liquid nitrogen and stored at -?80 °C until RNA extraction. Afterwards, LACC cells with miR-93-5p overexpression were subjected to qRT-PCR and western blot for epithelial-mesenchymal transition (EMT) markers levels. Ability of LACC cell migration, invasion, proliferation and apoptosis was examined by wounded healing, transwell, CCK-8 and apoptosis assays. Afterwards, TargetScan was used to predict putative targets of miR-93-5p. Then, the examination was performed whether miR-93-5p targets BRMS1L by the use of luciferase reporter assays and western blotting. Finally, immunohistochemical staining was sone and all the images were taken using a microscope (Nikon, Tokyo). Results:Our results showed that miR-93 was overexpressed in tissues and plasma of LACC patients compared to healthy controls. MiR-93 downregulated E-cadherin expression while increasing N-cadherin expression and significantly inhibited luciferase activity. Furthermore, western blotting results confirmed that miR-93-5p could inhibit BRMS1L expression. The BRMS1L staining in LACC tissues was weaker than in normal controls. In addition, miR-93-5p revealed a reverse correlation with the expression of BRMS1L. In addition, significant upregulation of E-cadherin and downregulation of N-cadherin were found when LACC cells were transfected with BRMS1L. Finally, miR-93-5p significantly enhanced TOP/FOP luciferase activity. Upregulation of BRMS1L reduced TOP/FOP luciferase activity while further overexpression of miR-93-5p could not rescue Wnt signaling activity. Conclusions:Our findings report that miR-93 promotes LACC cell migration, invasion, and proliferation via targeting downregulation of BRMS1L through regulation of Wnt signaling pathway.

Project description:BACKGROUND:Chemoresistance to temozolomide (TMZ) is a major challenge in the treatment of glioblastoma (GBM). We previously found that miR-519a functions as a tumor suppressor in glioma by targeting the signal transducer and activator of transcription 3 (STAT3)-mediated autophagy oncogenic pathway. Here, we investigated the effects of miR-519a on TMZ chemosensitivity and autophagy in GBM cells. Furthermore, the underlying molecular mechanisms and signaling pathways were explored. METHODS:In the present study, two stable TMZ-resistant GBM cell lines were successfully generated by exposure of parental cells to a gradually increasing TMZ concentration. After transfecting U87-MG/TMZ and U87-MG cells with miR-519a mimic or inhibitor, a series of biochemical assays such as MTT, apoptosis, and colony formation were performed to determine the chemosensitive response to TMZ. The autophagy levels in GBM cells were detected by transmission electron microscopy, LC3B protein immunofluorescence, and Western blotting analysis. Stable knockdown and overexpression of miR-519a in GBM cells were established using lentivirus. A xenograft nude mouse model and in situ brain model were used to examine the in vivo effects of miR-519a. Tumor tissue samples were collected from 48 patients with GBM and were used to assess the relationship between miR-519a and STAT3 expression. RESULTS:TMZ treatment significantly upregulated miR-519a in U87-MG cells but not in U87-MG/TMZ cells. Moreover, the expression of miR-519a and baseline autophagy levels was lower in U87-MG/TMZ cells as compared to U87-MG cells. miR-519a dramatically enhanced TMZ-induced autophagy and apoptotic cell death in U87-MG/TMZ cells, while inhibition of miR-519a promoted TMZ resistance and reduced TMZ-induced autophagy in U87-MG cells. Furthermore, miR-519a induced autophagy through modification of STAT3 expression. The in vivo results showed that miR-519a can enhance apoptosis and sensitized GBM to TMZ treatment by promoting autophagy and targeting the STAT3/Bcl-2/Beclin-1 pathway. In human GBM tissues, we found an inverse correlation between miR-519a and STAT3 expression. CONCLUSIONS:Our results suggested that miR-519a increased the sensitivity of GBM cells to TMZ therapy. The positive effects of miR-519a may be mediated through autophagy. In addition, miR-519a overexpression can induce autophagy by inhibiting STAT3/Bcl-2 pathway. Therefore, a combination of miR-519a and TMZ may represent an effective therapeutic strategy in GBM.

Dataset Information

MiR-93 suppresses tumorigenesis and enhances chemosensitivity of breast cancer via dual targeting E2F1 and CCND1.

Publications

MiR-93 suppresses tumorigenesis and enhances chemosensitivity of breast cancer via dual targeting E2F1 and CCND1.

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