Xin Huang1, Yang Xiao2, Lin Run3, Liping Wang3, Xiting Nong3, Nan Li3. 1. Department of General Surgery, Xi'an Central Hospital, Xi'an JiaoTong University, Xi'an, 710003, Shannxi, PR China. huangxincenter@126.com. 2. Department of Endocrinology, Shaanxi Traditional Chinese Medicine Hospital, Xi'an, 710003, Shannxi, PR China. xiaoyangsxzy@yeah.net. 3. Department of Endocrinology, Xi'an Central Hospital, Xi'an JiaoTong University, Xi'an, 710003, Shannxi, PR China.
Abstract
PURPOSE: Thyroid carcinoma is the most frequent endocrine malignancy with high occurrence of BRAFV600E mutations. Though targeted therapy by vemurafenib, a specific inhibitor for BRAFV600E, has achieved great advance in therapeutic landscape, resistance occurrence is still a clinical challenge. Here, we sought to elucidate the function of high mobility group box 1 (HMGB1) in vemurafenib resistance in thyroid cancer harboring BRAF mutation. METHODS: The expression of HMGB1 in BRAF-mutant BCPAP and BRAF-wild CAL-62 cells were determined by qRT-PCR and western. Then, BCPAP cells were transfected with recombinant HMGB1 plasmids, and vemurafenib-resistant BCPAP-R cells were treated with si-HMGB1. The efficacy of HMGB1 on vemurafenib resistance was evaluated by detecting cell viability, apoptosis, and caspase-3 activity. In addition, the involvement of autophagy pathway was investigated. RESULTS: Lower expression of HMGB1 was observed in BRAF-mutant BCPAP cells that had high sensitivity to vemurafenib. Overexpression of HMGB1 attenuated BCPAP cell sensitivity to vemurafenib by increasing cell viability and decreasing cell apoptosis and caspase-3 activity. Intriguingly, higher expression of HMGB1 was confirmed in vemurafenib-resistant BCPAP-R cells. Moreover, knockdown of HMGB1 sensitized BCPAP-R cells to vemurafenib resistance. Mechanistically, vemurafenib exposure induced autophagy by enhancing LC3II, Beclin-1 expression, and reducing autophagy substrate p62 expression. Importantly, targeting HMGB1 suppressed vemurafenib-induced autophagy. Blocking autophagy pathway with its inhibitor 3-MA offset BCPAP-R cell resistance to vemurafenib. CONCLUSIONS: These findings highlight that HMGB1-mediated autophagy may account for vemurafenib resistance in thyroid cancer harboring BRAF mutation, implying a promising approach to overcome vemurafenib resistance in vemurafenib-mutant thyroid carcinomas.
PURPOSE: Thyroid carcinoma is the most frequent endocrine malignancy with high occurrence of BRAFV600E mutations. Though targeted therapy by vemurafenib, a specific inhibitor for BRAFV600E, has achieved great advance in therapeutic landscape, resistance occurrence is still a clinical challenge. Here, we sought to elucidate the function of high mobility group box 1 (HMGB1) in vemurafenib resistance in thyroid cancer harboring BRAF mutation. METHODS: The expression of HMGB1 in BRAF-mutant BCPAP and BRAF-wild CAL-62 cells were determined by qRT-PCR and western. Then, BCPAP cells were transfected with recombinant HMGB1 plasmids, and vemurafenib-resistant BCPAP-R cells were treated with si-HMGB1. The efficacy of HMGB1 on vemurafenib resistance was evaluated by detecting cell viability, apoptosis, and caspase-3 activity. In addition, the involvement of autophagy pathway was investigated. RESULTS: Lower expression of HMGB1 was observed in BRAF-mutant BCPAP cells that had high sensitivity to vemurafenib. Overexpression of HMGB1 attenuated BCPAP cell sensitivity to vemurafenib by increasing cell viability and decreasing cell apoptosis and caspase-3 activity. Intriguingly, higher expression of HMGB1 was confirmed in vemurafenib-resistant BCPAP-R cells. Moreover, knockdown of HMGB1 sensitized BCPAP-R cells to vemurafenib resistance. Mechanistically, vemurafenib exposure induced autophagy by enhancing LC3II, Beclin-1 expression, and reducing autophagy substrate p62 expression. Importantly, targeting HMGB1 suppressed vemurafenib-induced autophagy. Blocking autophagy pathway with its inhibitor 3-MA offset BCPAP-R cell resistance to vemurafenib. CONCLUSIONS: These findings highlight that HMGB1-mediated autophagy may account for vemurafenib resistance in thyroid cancer harboring BRAF mutation, implying a promising approach to overcome vemurafenib resistance in vemurafenib-mutant thyroid carcinomas.
Authors: David M Hyman; Igor Puzanov; Vivek Subbiah; Jason E Faris; Ian Chau; Jean-Yves Blay; Jürgen Wolf; Noopur S Raje; Eli L Diamond; Antoine Hollebecque; Radj Gervais; Maria Elena Elez-Fernandez; Antoine Italiano; Ralf-Dieter Hofheinz; Manuel Hidalgo; Emily Chan; Martin Schuler; Susan Frances Lasserre; Martina Makrutzki; Florin Sirzen; Maria Luisa Veronese; Josep Tabernero; José Baselga Journal: N Engl J Med Date: 2015-08-20 Impact factor: 91.245
Authors: Elyse K Hanly; Robert B Bednarczyk; Neha Y Tuli; Augustine L Moscatello; H Dorota Halicka; Jiangwei Li; Jan Geliebter; Zbigniew Darzynkiewicz; Raj K Tiwari Journal: Oncotarget Date: 2015-11-24