Autophagy is involved in TGF-β1-induced protective mechanisms and formation of cancer-associated fibroblasts phenotype in tumor microenvironment
Metrics: PDF 3089 views | HTML 2913 views | ?
Fang-Lan Liu1, En-Pan Mo1, Liu Yang1, Jun Du2, Hong-Sheng Wang2, Huan Zhang1, Hiroshi Kurihara1, Jun Xu1, Shao-Hui Cai1
1Pharmacy College, Jinan University, Guangzhou 510632, China
2Pharmacy College, Sun Yat-Sen University, Guangzhou 510405, China
Shao-Hui Cai, e-mail: email@example.com
Jun Xu, e-mail: firstname.lastname@example.org
Keywords: autophagy, TGF-β1, tumor microenvironment, mitochondria, cancer-associated fibroblasts
Received: July 06, 2015 Accepted: December 02, 2015 Published: December 21, 2015
Transforming growth factor-β1 (TGF-β1) present in tumor microenvironment acts in a coordinated fashion to either suppress or promote tumor development. However, the molecular mechanisms underlying the effects of TGF-β1 on tumor microenvironment are not well understood. Our clinical data showed a positive association between TGF-β1 expression and cancer-associated fibroblasts (CAFs) in tumor microenvironment of breast cancer patients. Thus we employed starved NIH3T3 fibroblasts in vitro and 4T1 cells mixed with NIH3T3 fibroblasts xenograft model in vivo to simulate nutritional deprivation of tumor microenvironment to explore the effects of TGF-β1. We demonstrated that TGF-β1 protected NIH3T3 fibroblasts from Star-induced growth inhibition, mitochondrial damage and cell apoptosis. Interestingly, TGF-β1 induced the formation of CAFs phenotype in starvation (Star)-treated NIH3T3 fibroblasts and xenografted Balb/c mice, which promoted breast cancer tumor growth. In both models, autophagy agonist rapamycin increased TGF-β1-induced protective effects and formation of CAFs phenotypes, while autophagy inhibitor 3-methyladenine, Atg5 knockdown or TGF-β type I receptor kinase inhibitor LY-2157299 blocked TGF-β1 induced these effects. Taken together, our results indicated that TGF-β/Smad autophagy was involved in TGF-β1-induced protective effects and formation of CAFs phenotype in tumor microenvironment, which may be used as therapy targets in breast cancer.
All site content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 License.