A two-pronged “senolytic” approach to treatment of oral cavity cancer

摘要 口腔鳞状细胞癌的标准疗法(手术、放疗和顺铂) (OCSCC)几十年来没有改变，没有任何分子靶向药物具有 确立了作为一线治疗的角色。与HPV阳性的口咽癌不同，口咽癌有 预后良好，晚期OCSCC(主要是HPV阴性)具有很高的 复发率(~20-30%)和总生存率较差(5年~50%)。 OCSCC的生物学特征得到了很好的描述。P16INK4A(P16)功能缺失是驱动因素 细胞周期调控存在缺陷。P16抑制细胞周期蛋白依赖性激酶4和6(CDK4/6)， 导致细胞周期停滞于G1期。Fda批准的癌症治疗药物palbociclib是一种小型 靶向CDK4/6的分子抑制剂。我们的初步工作表明，Palbociclib一致 诱导口腔鳞状细胞癌细胞衰老。我们还表明，这些细胞一直 上调促生存分子bcl-xl对帕波西利的反应。 人们对癌症中的衰老细胞的靶向越来越感兴趣。虽然有些衰老 细胞不会增殖，它们已被证明能产生炎症信号，促进 并在肿瘤微环境中支持邻近的癌细胞。已经有越来越多的人 对专门针对衰老细胞的药剂(“抗衰老药物”)感兴趣。可能是最好的- 研究了抗衰老药物ABT-263(Navitoclax)，靶向BCL2家族促生存抗凋亡信号 分子、BCL2、BCL-XL和BCL-W。我们的初步工作表明，结合 Palbociclib(诱导衰老)与Navitoclax(减老剂)联合可导致大鼠脑内细胞深度凋亡 OCSCC细胞。 在这项建议中，我们的目标是广泛研究Palbociclib/Navitoclax的组合 OCSCC。在特定的目标#1中，我们将在一组OCSCC细胞中研究Palbociclib的反应 并同时处于一种“细胞重编程”模型中，该模型允许永久培养 原代口腔鳞状细胞癌肿瘤细胞来源于我们自己机构治疗的患者。我们会 具体测量衰老反应(特定目标#1a)和使用 一种称为‘BH3’分析的高通量方法(特定于Aim1b)。在具体目标2中，我们将 使用细胞存活率试验测量帕博西利和ABT-263(Navitoclax)之间的协同作用，以及 应用口腔鳞状细胞癌原位异种舌移植模型评价体内疗效。

ABSTRACT Standard therapies (surgery, radiation, and cisplatin) for oral cavity squamous cell carcinoma (OCSCC) have not changed for decades, and no molecularly targeted agents have an established role as first-line treatment. Unlike HPV-positive oropharynx cancer, which has an excellent prognosis, advanced OCSCC (which is predominantly HPV-negative) carries a high recurrence rate (~20-30%) and poor overall survival (~50% at 5 years). The biology of OCSCC is well described. Loss of p16INK4A (p16) function is the driving defect in cell cycle regulation. p16 inhibits cyclin-dependent kinases 4 and 6 (CDK4/6), which leads to cell cycle arrest in G1. The FDA-approved cancer therapeutic, palbociclib, is a small molecule inhibitor that targets CDK4/6. Our preliminary work shows that palbociclib consistently induces senescence in OCSCC cells. We have also shown that these cells consistently upregulate the pro-survival molecule, BCL-xL, in response to palbociclib. There has been growing interest in targeting senescent cells in cancer. Though senescent cells do not proliferate, they have been shown to produce inflammatory signals that promote and support neighboring cancer cells in the tumor micorenvironment. There has been growing interest in agents that specifically target senescent cells (‘senolytics’). Perhaps the most well- studied senolytic, ABT-263 (navitoclax), targets BCL2 family pro-survival anti-apoptotic signaling molecules, BCL2, BCL-xL, and BCL-w. Our preliminary work has shown that combining palbociclib (inducing senescence) with navitoclax (senolytic) results in profound apoptosis in OCSCC cells. In this proposal, we aim to study the palbociclib/navitoclax combination extensively in OCSCC. In Specific Aim #1, we will study the response to palbociclib in a panel of OCSCC cell lines, and concurrently in a ‘cell reprogramming’ model, which allows perpetual culture of primary OCSCC tumor cells derived from patients treated at our own institution. We will specifically measure the senescence response (Specific Aim#1a) and apoptosis signaling using a high throughput method called ‘BH3’ profiling (Specific Aim1b). In Specific Aim#2 we will measure synergy between palbociclib and ABT-263 (navitoclax) using cell viability assays, and evaluate in vivo efficacy using an orthotopic tongue xenograft model of OCSCC.