autophagy

Yes-associated protein plays oncogenic roles in human sporadic colorectal adenomas

AUTHORS

Lei Fan, Xingyi Guo, Mary K Washington, Jiajun Shi, Reid M Ness, Qi Liu, Wanqing Wen, Shuya Huang, Xiao Liu, Qiuyin Cai, Wei Zheng, Robert J Coffey, Martha J Shrubsole, Timothy Su

ABSTRACT

The role of Hippo-Yes-associated protein (YAP) in human colorectal cancer (CRC) presents contradictory results. We examined the function of YAP in the early stages of CRC by quantitatively measuring the expression of phospho-YAPS127 (p-YAP) and five APC-related proteins in 145 sporadic adenomas from the Tennessee Colorectal Polyp Study, conducting APC sequencing for 114 adenomas, and analyzing YAP-correlated cancer pathways using gene expression data from 326 adenomas obtained from Gene Expression Omnibus. The p-YAP expression was significantly correlated with YAP expression (r = 0.53, P < .0001) and nuclear β-catenin (r = 0.26, P = .0018) in adenoma tissues. Both p-YAP and nuclear β-catenin were associated with APC mutations (P = .05). A strong association was observed between p-YAP overexpression and advanced adenoma odds (OR = 12.62, 95% CI = 4.57–34.86, P trend < .001), which persisted after adjusting for covariates and biomarkers (OR = 12.31, 95% CI = 3.78–40.10, P trend < .0001). P-YAP exhibited a sensitivity of 77.4% and specificity of 78.2% in defining advanced versus nonadvanced adenomas. Additionally, synergistic interaction was noted between p-YAP positivity and nuclear β-catenin on advanced adenomas (OR = 16.82, 95% CI = 4.41–64.08, P < .0001). YAP-correlated genes were significantly enriched in autophagy, unfolded protein response, and sirtuin pathways showing predominantly pro-tumorigenic alterations. Collectively, YAP plays an oncogenic role in interacting with Wnt as well as other cancer pathways within human sporadic adenomas. P-YAP could be a potential biomarker for human high-risk sporadic adenomas.

TET2 regulates osteoclastogenesis by modulating autophagy in OVX-induced bone loss

AUTHORS

Chen Yang, Huaqiang Tao, Haifeng Zhang, Yu Xia, Jiaxiang Bai, Gaoran Ge, Wenming Li, Wei Zhang, Long Xiao, Yaozeng Xu, Zhirong Wang, Ye Gu,H uilin Yang, Yu Liu & Dechun Geng

ABSTRACT

Increased bone resorption by osteoclasts after estrogen deficiency is the main cause of postmenopausal osteoporosis. TET2 (tet methylcytosine dioxygenase 2) is a DNA demethylase that regulates cellular function and differentiation potential. Macroautophagy/autophagy maintains cellular homeostasis by recycling unnecessary and damaged organelles. This study revealed that TET2 promoted bone loss in oophorectomized (OVX) mice and that TET2 promoted osteoclast differentiation by regulating autophagy. Tet2 knockdown inhibited autophagy and osteoclast differentiation in vitro. Mechanistically, Tet2 knockdown increased BCL2 (B cell leukemia/lymphoma 2) expression and BCL2 exhibited increased binding to BECN1 and negatively regulated autophagy. Small interfering RNA specific to Bcl2 interfered with BCL2 expression in Tet2-knockdown bone marrow cells/precursors, partially reversing autophagy dysregulation and promoting osteoclast differentiation. Moreover, the LV-shTet2 lentivirus prevented bone loss in OVX mice. In summary, our findings provide evidence that TET2 promotes osteoclast differentiation by inhibiting BCL2 expression and positively regulating BECN1-dependent autophagy.