Zhen-Ru Liu1, Yi Song2, Li-Hong Wan1, Yuan-Yuan Zhang3, Li-Mimg Zhou4. 1. Department of Pharmacology, West China School of Preclinical and Forensic Medicine, Sichuan University, Chengdu, Sichuan 610041, PR China. 2. Department of Pharmacy, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, PR China. 3. Department of Pharmacology, West China School of Preclinical and Forensic Medicine, Sichuan University, Chengdu, Sichuan 610041, PR China. Electronic address: sarahyyzhang@hotmail.com. 4. Department of Pharmacology, West China School of Preclinical and Forensic Medicine, Sichuan University, Chengdu, Sichuan 610041, PR China; 985 Science and Technology Platform for Innovative Drugs, Sichuan University, Chengdu, Sichuan 610041, PR China. Electronic address: zhou1081@hotmail.com.
Abstract
AIM: To investigate the effects and mechanisms of miR-451a in the tamoxifen (TAM) resistance of breast cancer cells. MATERIALS AND METHODS: TAM sensitive cells (MCF-7) and resistant cells (LCC2) were employed in the study. The lentivirus vectors of Lv-miR-451a, Lv-miR-451a sponge, and Lv-miR-451a NC were employed to increase or decrease the expression of miR-451a, respectively. SiRNA to 14-3-3ζ was used to inhibit expression of 14-3-3ζ. MTT assay was utilized to detect breast cancer cell proliferation. AnnexinV-FITC binding assay was used to detect apoptosis. Expression of ERα, 14-3-3ζ and miR-451a were measured by qRT-PCR and Western blot analysis. Interactions between 14-3-3ζ and ERα were investigated by co-immunoprecipitation. LC3-II surface expression and intracellular autophagosomes were observed by Western blot and electron microscopy. KEY FINDINGS: Over-expression of miR-451a can enhance MCF-7 and LCC2 cell sensitivity to TAM. Opposite effects were elicited by knocking down miR-451a. TAM treatment can up-regulate 14-3-3ζ expression, and down-regulate ERα expression. 14-3-3ζ and ERα were shown to interact. Over-expression of miR-451a decreased 14-3-3ζ expression and increased ERα expression, suppressing cell proliferation, increasing apoptosis, and reducing activation of p-AKT and p-mTOR. R18 can significantly decrease cell proliferation and increase apoptosis. R18 and 14-3-3ζ siRNA can rescue the effects of down-regulation of ERα by knocking down miR-451a. Over-expression of miR-451a inhibits autophagy, knocking-down miR-451a stimulates autophagy. SIGNIFICANCE: MiR-451a functions as a suppressor of resistance to TAM through regulating autophagy, the expression of 14-3-3ζ and ERα. This suggests miR-451a to be a potential target for reversing resistance to TAM.
AIM: To investigate the effects and mechanisms of miR-451a in the tamoxifen (TAM) resistance of breast cancer cells. MATERIALS AND METHODS:TAM sensitive cells (MCF-7) and resistant cells (LCC2) were employed in the study. The lentivirus vectors of Lv-miR-451a, Lv-miR-451a sponge, and Lv-miR-451a NC were employed to increase or decrease the expression of miR-451a, respectively. SiRNA to 14-3-3ζ was used to inhibit expression of 14-3-3ζ. MTT assay was utilized to detect breast cancer cell proliferation. AnnexinV-FITC binding assay was used to detect apoptosis. Expression of ERα, 14-3-3ζ and miR-451a were measured by qRT-PCR and Western blot analysis. Interactions between 14-3-3ζ and ERα were investigated by co-immunoprecipitation. LC3-II surface expression and intracellular autophagosomes were observed by Western blot and electron microscopy. KEY FINDINGS: Over-expression of miR-451a can enhance MCF-7 and LCC2 cell sensitivity to TAM. Opposite effects were elicited by knocking down miR-451a. TAM treatment can up-regulate 14-3-3ζ expression, and down-regulate ERα expression. 14-3-3ζ and ERα were shown to interact. Over-expression of miR-451a decreased 14-3-3ζ expression and increased ERα expression, suppressing cell proliferation, increasing apoptosis, and reducing activation of p-AKT and p-mTOR. R18 can significantly decrease cell proliferation and increase apoptosis. R18 and 14-3-3ζ siRNA can rescue the effects of down-regulation of ERα by knocking down miR-451a. Over-expression of miR-451a inhibits autophagy, knocking-down miR-451a stimulates autophagy. SIGNIFICANCE: MiR-451a functions as a suppressor of resistance to TAM through regulating autophagy, the expression of 14-3-3ζ and ERα. This suggests miR-451a to be a potential target for reversing resistance to TAM.
Authors: C Chang; J Liu; W He; M Qu; X Huang; Y Deng; L Shen; X Zhao; H Guo; J Jiang; X Y Fu; R Huang; D Zhang; J Yan Journal: Oncogene Date: 2017-10-02 Impact factor: 9.867
Authors: Alma D Campos-Parra; Gerardo Cuamani Mitznahuatl; Abraham Pedroza-Torres; Rafael Vázquez Romo; Fany Iris Porras Reyes; Eduardo López-Urrutia; Carlos Pérez-Plasencia Journal: Int J Mol Sci Date: 2017-06-02 Impact factor: 5.923