a Departments of Biochemistry and Molecular Biology , Virginia Commonwealth University , Richmond , VA.
b Departments of Medicine , Virginia Commonwealth University , Richmond , VA.
Cancer Biol Ther. 2017 Sep 2;18(9):705-714. doi: 10.1080/15384047.2017.1362511.
Pemetrexed is an approved therapeutic in NSCLC and ovarian cancer. Our studies focused on the ability of [pemetrexed + sildenafil] exposure to alter the immunogenicity of lung and ovarian cancer cells. Treatment of lung and ovarian cancer cells with [pemetrexed + sildenafil] in vitro rapidly reduced the expression of PD-L1, PD-L2 and ornithine decarboxylase (ODC), and increased the expression of class I MHCA. In a cell-specific fashion, some cells also released the immunogenic nuclear protein HMGB1 into the extracellular environment. [Pemetrexed + sildenafil] reduced the expression of multiple histone deacetylases that was blocked by knock down of autophagy regulatory proteins. [Pemetrexed + sildenafil] lethality was enhanced by the histone deacetylase inhibitors AR42 and sodium valproate; AR42 and valproate as single agents also rapidly reduced the expression of PD-L1, PD-L2 and ODC, and increased expression of MHCA and CerS6. Nitric oxide and CerS6 signaling was required for drug-induced death receptor activation and tumor cell killing. In vivo, [pemetrexed + sildenafil] lethality against lung cancer cells was enhanced by sodium valproate. Using syngeneic mouse lung cancer cells [pemetrexed + sildenafil] enhanced the anti-tumor effects of antibodies directed to inhibit PD-1 or CTLA4. [Pemetrexed + sildenafil] interacted with the anti-PD-1 antibody to strongly enhance tumor infiltration by M1 macrophages; activated NK cells and activated T cells. Our data demonstrate that treatment of tumor cells with [pemetrexed + sildenafil] results in tumor cell killing and via autophagy-dependent downregulation of HDACs, it opsonizes the remaining tumor cells to anti-tumor immunotherapy antibodies.
培美曲塞是一种已被批准用于治疗非小细胞肺癌和卵巢癌的药物。我们的研究集中在[培美曲塞+西地那非]联合暴露对肺和卵巢癌细胞免疫原性的改变能力上。体外实验结果表明，[培美曲塞+西地那非]处理肺和卵巢癌细胞可迅速降低 PD-L1、PD-L2 和鸟氨酸脱羧酶（ODC）的表达，增加 I 类主要组织相容性复合物（MHC）A 的表达。以细胞特异性方式，一些细胞还将免疫原性核蛋白 HMGB1 释放到细胞外环境中。[培美曲塞+西地那非]联合处理可降低多种组蛋白去乙酰化酶的表达，而自噬调控蛋白敲低可阻断这一作用。组蛋白去乙酰化酶抑制剂 AR42 和丙戊酸钠可增强[培美曲塞+西地那非]的致死作用；AR42 和丙戊酸钠单独作用也可迅速降低 PD-L1、PD-L2 和 ODC 的表达，增加 MHC 和 CerS6 的表达。一氧化氮和 CerS6 信号通路是药物诱导死亡受体激活和肿瘤细胞杀伤所必需的。在体内，丙戊酸钠可增强[培美曲塞+西地那非]对肺癌细胞的致死作用。使用同源小鼠肺癌细胞，[培美曲塞+西地那非]增强了针对抑制 PD-1 或 CTLA4 的抗体的抗肿瘤作用。[培美曲塞+西地那非]与抗 PD-1 抗体相互作用可强烈增强 M1 巨噬细胞、激活的自然杀伤细胞和激活的 T 细胞对肿瘤的浸润。我们的数据表明，用[培美曲塞+西地那非]处理肿瘤细胞可导致肿瘤细胞死亡，并且通过自噬依赖性下调 HDAC，可使剩余的肿瘤细胞对抗肿瘤免疫治疗抗体敏感。
