251. Cx43 deficiency confers EMT-mediated tamoxifen resistance to breast cancer via c-Src/PI3K/Akt pathway
- Author
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Tian-Yu Lin, Bei Zhang, Xiao-Xing Yin, Wen Yi, Si-Man Yang, Yan Zhou, Jin-Lan Huang, Deng-Pan Wu, Li-Xiang Hou, and Xiao-Xiao Zhu
- Subjects
Antineoplastic Agents, Hormonal ,c-Src/PI3K/Akt pathway ,Class I Phosphatidylinositol 3-Kinases ,tamoxifen resistance ,epithelial-mesenchymal transition ,Mice, Nude ,Connexin ,Breast Neoplasms ,Applied Microbiology and Biotechnology ,Breast cancer ,stomatognathic system ,Tamoxifen resistance ,Animals ,Humans ,Medicine ,In patient ,Epithelial–mesenchymal transition ,skin and connective tissue diseases ,Molecular Biology ,Ecology, Evolution, Behavior and Systematics ,PI3K/AKT/mTOR pathway ,Mice, Inbred BALB C ,business.industry ,Cell Biology ,medicine.disease ,Survival Analysis ,Xenograft Model Antitumor Assays ,Tamoxifen ,src-Family Kinases ,Drug Resistance, Neoplasm ,Connexin 43 ,MCF-7 Cells ,cardiovascular system ,Cancer research ,Female ,sense organs ,business ,Proto-Oncogene Proteins c-akt ,hormones, hormone substitutes, and hormone antagonists ,Signal Transduction ,Research Paper ,Developmental Biology ,medicine.drug ,Proto-oncogene tyrosine-protein kinase Src - Abstract
Tamoxifen (TAM) resistance has indicated a significant challenge during endocrine therapy for hormone-sensitive breast cancer. Thus, it is significant to elucidate the molecular events endowing TAM resistance to endocrine therapy. In this study, we found that epithelial-mesenchymal transition (EMT) was an important event to confer TAM resistance, and attenuating EMT by elevating connexin (Cx) 43 expression could reverse TAM resistance. Specifically, Cx43 overexpression improved TAM sensitivity, while Cx43 depletion facilitated TAM insensitivity by modulating EMT in T47D TAM-resistant and -sensitive cells, and transplanted xenografts. Importantly, we found a novel reciprocal regulation between Cx43 and c-Src/PI3K/Akt pathway contributing to EMT and TAM resistance in breast cancer. Moreover, we identified that Cx43 deficiency was significantly correlated with poor relapse-free survival in patients undergoing TAM treatment. Therefore, Cx43 represents a prognostic marker and an attractive target for breast cancer treatments. Therapeutic strategies designed to increase or maintain Cx43 function may be beneficial to overcome TAM resistance.
- Published
- 2021
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