Yazbeck Victor Y, Li Changyou, Grandis Jennifer R, Zang Yan, Johnson Daniel E
Department of Medicine, University of Pittsburgh, University of Pittsburgh Cancer Institute, Pittsburgh, PA, United States.
Department of Otolaryngology, University of Pittsburgh, University of Pittsburgh Cancer Institute, Pittsburgh, PA, United States; Department of Pharmacology & Chemical Biology, University of Pittsburgh, University of Pittsburgh Cancer Institute, Pittsburgh, PA, United States.
Oral Oncol. 2014 Feb;50(2):120-7. doi: 10.1016/j.oraloncology.2013.10.013. Epub 2013 Nov 8.
More than half of head and neck squamous cell carcinoma (HNSCC) patients are initially treated with curative intent, but will relapse over the course of their disease and have poor prognosis with a median survival of approximately 6months. Novel therapeutic approaches are in desperate need for this patient population. The anti-apoptotic BCL-2 family proteins such as BCL-2, BCL-XL, and MCL-1 are involved in oncogenesis and chemoresistance and are overexpressed in HNSCC. Obatoclax is a small-molecule antagonist of the BH3-binding groove of anti-apoptotic BCL-2 family. We evaluated the activity of obatoclax against 4 HNSCC cell lines (UMSCC-1, Cal33, 1483, UMSCC-22A).
Cell viability was determined by MTT assay, cell cycle status by propidium iodide staining, and apoptosis by Annexin-V staining and immunoblotting. Autophagy was assessed by immunofluorescence and immunoblotting.
All four HNSCC cell lines were highly sensitive to single-agent obatoclax with IC50's ranging from 46 to 177nM. Obatoclax induced apoptosis in all four HNSCC cell lines as evidenced by increases in sub-G1 DNA content, Annexin-V staining, and PARP cleavage. In addition, obatoclax induced autophagy in all 4 cell lines, and the addition of the autophagy inhibitor chloroquine enhanced obatoclax cytotoxicity.
Our findings demonstrate potent monotherapeutic activity of obatoclax against HNSCC cells, and enhancement of this activity in the presence of chloroquine. This preclinical study suggests that obatoclax might have therapeutic value in the treatment of HNSCC, either alone or in combination with inhibitors of autophagy.
超过半数的头颈部鳞状细胞癌（HNSCC）患者最初接受的是根治性治疗，但疾病过程中会复发，预后较差，中位生存期约为6个月。该患者群体迫切需要新的治疗方法。抗凋亡的BCL-2家族蛋白，如BCL-2、BCL-XL和MCL-1，参与肿瘤发生和化疗耐药，且在HNSCC中过表达。奥巴托克斯是一种抗凋亡BCL-2家族BH3结合凹槽的小分子拮抗剂。我们评估了奥巴托克斯对4种HNSCC细胞系（UMSCC-1、Cal33、1483、UMSCC-22A）的活性。
通过MTT法测定细胞活力，通过碘化丙啶染色测定细胞周期状态，通过膜联蛋白V染色和免疫印迹测定细胞凋亡。通过免疫荧光和免疫印迹评估自噬。
所有4种HNSCC细胞系对单药奥巴托克斯高度敏感，IC50范围为46至177nM。奥巴托克斯在所有4种HNSCC细胞系中诱导凋亡，表现为亚G1期DNA含量增加、膜联蛋白V染色和PARP裂解。此外，奥巴托克斯在所有4种细胞系中诱导自噬，添加自噬抑制剂氯喹可增强奥巴托克斯的细胞毒性。
我们的研究结果表明奥巴托克斯对HNSCC细胞具有强大的单药治疗活性，且在氯喹存在下这种活性增强。这项临床前研究表明，奥巴托克斯单独或与自噬抑制剂联合使用可能对HNSCC治疗具有治疗价值。
