Ow Thomas J, Fulcher Cory D, Thomas Carlos, Broin Pilib Ó, López Andrea, Reyna Denis E, Smith Richard V, Sarta Catherine, Prystowsky Michael B, Schlecht Nicolas F, Schiff Bradley A, Rosenblatt Gregory, Belbin Thomas J, Harris Thomas M, Childs Geoffrey C, Kawachi Nicole, Guha Chandan, Gavathiotis Evripidis
Department of Otorhinolaryngology-Head and Neck Surgery, Montefiore Medical Center/Albert Einstein College of Medicine, Bronx, NY, USA.
Department of Pathology, Montefiore Medical Center/Albert Einstein College of Medicine, Bronx, NY, USA.
Oncotarget. 2019 Jan 11;10(4):494-510. doi: 10.18632/oncotarget.26563.
Mechanisms of treatment resistance in head and neck squamous cell carcinoma (HNSCC) are not well characterized. In this study, HNSCC tumors from a cohort of prospectively enrolled subjects on an ongoing tissue banking study were divided into those that persisted or recurred locoregionally (n=23) and those that responded without recurrence (n=35). Gene expression was evaluated using llumina HumanHT-12-v3 Expression BeadChip microarrays. Sparse Partial Least Squares - Discriminant Analysis (sPLS-DA) identified 135 genes discriminating treatment-resistant from treatment-sensitive tumors. BCL-xL was identified among 23% of canonical pathways derived from this set of genes using Ingenuity Pathway analysis. The BCL-xL protein was expressed in 8 HNSCC cell lines examined. Cells were treated with the BCL-xL inhibitor, ABT-263 (navitoclax): the average half maximal inhibitory concentration (IC50) was 8.9μM (range 6.6μM - 13.9μM). Combining ABT-263 did not significantly increase responses to 2 Gy radiation or cisplatin in the majority of cell lines. MCL-1, a potential mediator of resistance to ABT-263, was expressed in all cell lines and HNSCC patient tumors, in addition to BCL-xL. Treatment with the MCL-1 inhibitor, A-1210477, in HNSCC cell lines showed an average IC50 of 10.7μM (range, 8.8μM to 12.7μM). Adding A-1210477 to ABT-263 (navitoclax) treatment resulted in an average 7-fold reduction in the required lethal dose of ABT-263 (navitoclax) when measured across all 8 cell lines. Synergistic activity was confirmed in PCI15B, Detroit 562, MDA686LN, and HN30 based on Bliss Independence analysis. This study demonstrates that targeting both BCL-xL and MCL-1 is required to optimally inhibit BCL-family pro-survival molecules in HNSCC, and co-inhibition is synergistic in HNSCC cancer cells.
头颈部鳞状细胞癌（HNSCC）的治疗耐药机制尚未得到充分表征。在本研究中，一项正在进行的组织库研究中前瞻性招募的受试者队列中的HNSCC肿瘤被分为局部持续或复发的肿瘤（n = 23）和无复发反应的肿瘤（n = 35）。使用Illumina HumanHT-12-v3表达微珠芯片评估基因表达。稀疏偏最小二乘判别分析（sPLS-DA）确定了135个区分治疗耐药肿瘤和治疗敏感肿瘤的基因。使用Ingenuity通路分析从这组基因衍生的23%的经典通路中鉴定出BCL-xL。在所检测的8种HNSCC细胞系中均表达了BCL-xL蛋白。用BCL-xL抑制剂ABT-263（navitoclax）处理细胞：平均半数最大抑制浓度（IC50）为8.9μM（范围6.6μM - 13.9μM）。在大多数细胞系中，联合使用ABT-263并没有显著增加对2 Gy辐射或顺铂的反应。除了BCL-xL外，MCL-1作为对ABT-263耐药的潜在介导因子，在所有细胞系和HNSCC患者肿瘤中均有表达。在HNSCC细胞系中用MCL-1抑制剂A-1210477处理，平均IC50为10.7μM（范围8.8μM至12.7μM）。在所有8种细胞系中进行测量时，将A-1210477添加到ABT-263（navitoclax）治疗中，导致所需的ABT-263（navitoclax）致死剂量平均降低7倍。基于布利斯独立性分析，在PCI15B、底特律562、MDA686LN和HN30中证实了协同活性。本研究表明，在HNSCC中，需要同时靶向BCL-xL和MCL-1才能最佳抑制BCL家族促生存分子，并且联合抑制在HNSCC癌细胞中具有协同作用。
