Blockade of intrinsic PD-1 promotes survival, chemo resistance and tumor growth in human colon cancer. Blockade of intrinsic PD-1 promotes survival, chemo resistance and tumor growth in human colon cancer

Human colon cancer cells HT29, HCT116, LoVo robustly expressed PD-1. PD-1 signaling significantly decreased proliferation and promoted apoptosis in PD1+human colon cancer cells. The human anti-PD-1, Nivolumab (NIVO) ptomoted proliferation through pERK/pAKT signaling, reduced apoptosis and protected PD-1+ cells from Chemo/Radiotherapy (CRT). In vivo, NIVO promoted HT29 tumor growth reducing Oxaliplatin (OX) efficacy. As opposite to colon cancer cells, PD-1 signaling protects melanoma cells, thus NIVO treated human colon versus melanoma cancer cells, PES43 were evaluated for RNAseq. Among the commonly affected genes, opposite regulation was revealed between HT29 and HCT116 colon versus PES43 melanoma cells. BATF2, DRAM1, FXYD3, IFIT3, MT-TN, TNFRSF11A were upregulated in PES43 and downregulated in HT29 and HCT116 while CLK1, DCAF13, DNAJC2, MTHFD1L, PRPF3, PSMD7, SCFD1 were downregulated in PES43 and upregulated in HT29 and HCT116. DEGs were significantly enriched in the functional categories of the interferon pathway, innate immune, cytokine-mediated signaling pathway, neutrophil activation, immune effector process, granulocyte activation and cellular nitrogen compound metabolic process. Moreover, intrinsic PD-1 was expressed in 11/48 (22.9%) primary colorectal cancer and associated with tumor dimension (pT). Thus, PD-1 inhibition through NIVO protects human colon cancer cells and activate tumor survival pathways Overall design: mRNA profile Nivolumab (NIVO), soluble PD-L1 (sPDL-1) and NIVO+sPDL-1-treated human colorectal cancer cells HCT116 and HT29 and human melanoma cells PES43 for 6h and 24h

人结肠癌细胞HT29、HCT116及LoVo均可高表达程序性死亡受体1（PD-1）。PD-1信号通路可显著抑制PD-1阳性人结肠癌细胞的增殖并促进其凋亡。人源抗PD-1抗体纳武利尤单抗（Nivolumab, NIVO）可通过pERK/pAKT信号通路促进细胞增殖、抑制凋亡，并能保护PD-1阳性细胞免受化疗/放疗（Chemo/Radiotherapy, CRT）的损伤。在体实验中，NIVO可促进HT29异种移植瘤的生长，降低奥沙利铂（Oxaliplatin, OX）的抗肿瘤疗效。与结肠癌细胞不同，PD-1信号通路对黑色素瘤细胞具有保护作用，因此本研究对经NIVO处理的人结肠癌细胞与黑色素瘤细胞PES43进行了转录组测序（RNAseq）。在共同受到调控的基因中，HT29、HCT116结肠癌细胞与PES43黑色素瘤细胞的基因表达呈现相反的调控模式：BATF2、DRAM1、FXYD3、IFIT3、MT-TN、TNFRSF11A在PES43细胞中呈上调表达，而在HT29与HCT116细胞中呈下调表达；与之相反，CLK1、DCAF13、DNAJC2、MTHFD1L、PRPF3、PSMD7、SCFD1在PES43细胞中呈下调表达，在HT29与HCT116细胞中呈上调表达。差异表达基因（DEGs）显著富集于干扰素通路、固有免疫、细胞因子介导的信号通路、中性粒细胞活化、免疫效应过程、粒细胞活化以及细胞氮化合物代谢过程等功能类别。此外，11/48（22.9%）的原发性结直肠癌组织中可检测到内源性PD-1表达，且其表达与肿瘤分期（pT）显著相关。综上，通过NIVO抑制PD-1可对人结肠癌细胞产生保护作用，并激活肿瘤存活相关信号通路。实验整体设计：将人结直肠癌细胞HCT116、HT29及人黑色素瘤细胞PES43分别经纳武利尤单抗（NIVO）、可溶性PD-L1（sPDL-1）以及NIVO+sPDL-1处理6小时与24小时后，进行mRNA表达谱分析。