PURPOSE: Molecular targeted drugs, such as mTORC1 inhibitors, have been clinically popularized for advanced renal cell carcinoma treatment but metastasis is still a serious concern. mTORC2 has several important functions, including HIF-2α activation in malignant cells. HIF-2α suppresses E-cadherin expression, which is associated with tumor invasion and metastasis. We investigated whether mTORC2 regulates E-cadherin expression and controls cell motility during HIF-2α down-regulation in renal cell carcinoma cells. MATERIALS AND METHODS: We used PP242, a dual inhibitor of mTORC1/mTORC2 and the mTORC1 specific inhibitor rapamycin. E-cadherin expression in 786-O cells was examined using real-time polymerase chain reaction, Western blot and immunocytochemical staining. Cell motility was analyzed by time-lapse microscopy and wound healing assay. RESULTS: High E-cadherin expression was found in RCC4/VHL cells but low levels were found in VHL defective RCC4 and 786-O cells. HIF-2α expression was suppressed only in RCC4/VHL cells. In 786-O cells HIF-2α inhibition induced by the dual mTORC1/C2 inhibitor PP242 (0.05 to 0.5 μmol/L) resulted in a dose dependent increase in E-cadherin expression and the restored E-cadherin was localized at cell-to-cell junctions. Treatment with the mTORC1 inhibitor rapamycin resulted in no significant change. The migration of PP242 treated cells was significantly suppressed compared with those treated with rapamycin. CONCLUSIONS: Results show that mTORC2 might regulate E-cadherin expression and suppress cell motility by controlling the mTORC2-HIF-2α signaling pathway. The dual inhibitor of mTORC1/C2 as a cadherin regulatory agent may be a novel therapeutic strategy with tumoricidal agents for advanced renal cell carcinoma.
PURPOSE: Molecular targeted drugs, such as mTORC1 inhibitors, have been clinically popularized for advanced renal cell carcinoma treatment but metastasis is still a serious concern. mTORC2 has several important functions, including HIF-2α activation in malignant cells. HIF-2α suppresses E-cadherin expression, which is associated with tumor invasion and metastasis. We investigated whether mTORC2 regulates E-cadherin expression and controls cell motility during HIF-2α down-regulation in renal cell carcinoma cells. MATERIALS AND METHODS: We used PP242, a dual inhibitor of mTORC1/mTORC2 and the mTORC1 specific inhibitor rapamycin. E-cadherin expression in 786-O cells was examined using real-time polymerase chain reaction, Western blot and immunocytochemical staining. Cell motility was analyzed by time-lapse microscopy and wound healing assay. RESULTS: High E-cadherin expression was found in RCC4/VHL cells but low levels were found in VHL defective RCC4 and 786-O cells. HIF-2α expression was suppressed only in RCC4/VHL cells. In 786-O cells HIF-2α inhibition induced by the dual mTORC1/C2 inhibitor PP242 (0.05 to 0.5 μmol/L) resulted in a dose dependent increase in E-cadherin expression and the restored E-cadherin was localized at cell-to-cell junctions. Treatment with the mTORC1 inhibitor rapamycin resulted in no significant change. The migration of PP242 treated cells was significantly suppressed compared with those treated with rapamycin. CONCLUSIONS: Results show that mTORC2 might regulate E-cadherin expression and suppress cell motility by controlling the mTORC2-HIF-2α signaling pathway. The dual inhibitor of mTORC1/C2 as a cadherin regulatory agent may be a novel therapeutic strategy with tumoricidal agents for advanced renal cell carcinoma.
Authors: Nikki A Evensen; Yiyi Li; Cem Kuscu; Jingxuan Liu; Jillian Cathcart; Anna Banach; Qian Zhang; Ellen Li; Sonia Joshi; Jie Yang; Paula I Denoya; Silvia Pastorekova; Stanley Zucker; Kenneth R Shroyer; Jian Cao Journal: Oncotarget Date: 2015-08-21
Authors: Jordi Vilardell; Estefania Alcaraz; Eduard Sarró; Enric Trilla; Thaïs Cuadros; Inés de Torres; Maria Plana; Santiago Ramón Y Cajal; Lorenzo A Pinna; Maria Ruzzene; Juan Morote; Anna Meseguer; Emilio Itarte Journal: Oncotarget Date: 2017-12-19