Univ Lyon, Université Claude Bernard Lyon 1, INSERM 1052, CNRS 5286, Centre Léon Bérard, Centre de Recherche en Cancérologie de Lyon, Lyon, France.
Antineo, Lyon, France.
Cancer Immunol Res. 2022 Aug 3;10(8):1013-1027. doi: 10.1158/2326-6066.CIR-21-0802.
Antibodies targeting PD-1 and PD-L1 have produced durable responses in a subset of patients with cancer. However, a majority of these patients will ultimately relapse due to acquired resistance. To explore the underlying mechanisms of this secondary resistance, we developed five syngeneic murine tumor variants with acquired resistance to anti-PD-1 and/or PD-L1 antibodies in vivo. Resistant in vivo models were obtained by serial treatment/reimplantation cycles of the MC38 colorectal, MB49 and MBT2 bladder, and RENCA kidney and TyrNras melanoma models. Tumor immune infiltrates were characterized for wild type and resistant tumors using spectral cytometry and their molecular alterations analyzed using RNA sequencing analyses. Alterations in the tumor immune microenvironment were strongly heterogeneous among resistant models, involving select lymphoid and/or myeloid subpopulations. Molecular alterations in resistant models included previously identified pathways as well as novel candidate genes found to be deregulated in several resistant models. Among these, Serpinf1, coding for pigment epithelial-derived factor (PEDF) was further explored in the MC38 and the MBT2 models. Overexpression of Serpinf1 induced resistance to anti-PD-1 antibodies in the MC38 model, whereas knockdown of Serpinf1 sensitized this model as well as the primarily resistant MBT2 model. Serpinf1 overexpression was associated with increased production of free fatty acids and reduced activation of CD8+ cells, while orlistat, a compound that reduces the production of free fatty acids, reversed resistance to anti-PD-1 therapy. Our results suggest that a panel of syngeneic resistant models constitutes a useful tool to model the heterogeneity of resistance mechanisms encountered in the clinic.
针对 PD-1 和 PD-L1 的抗体在一部分癌症患者中产生了持久的应答。然而，这些患者中的大多数最终会因获得性耐药而复发。为了探索这种继发性耐药的潜在机制，我们开发了五种对体内抗 PD-1 和/或 PD-L1 抗体产生获得性耐药的同基因小鼠肿瘤变体。通过对 MC38 结肠、MB49 和 MBT2 膀胱、RENCA 肾和 TyrNras 黑色素瘤模型的连续治疗/再植入周期，获得了耐药的体内模型。使用光谱细胞术对野生型和耐药肿瘤进行了肿瘤免疫浸润的特征分析，并通过 RNA 测序分析对其分子改变进行了分析。在耐药模型中，肿瘤免疫微环境的改变存在强烈的异质性，涉及选择性的淋巴和/或髓样亚群。耐药模型中的分子改变包括以前确定的途径以及在几个耐药模型中发现的新的候选基因。在这些基因中，编码色素上皮衍生因子（PEDF）的 Serpinf1 在 MC38 和 MBT2 模型中进一步进行了研究。Serpinf1 的过表达在 MC38 模型中诱导了对抗 PD-1 抗体的耐药性，而 Serpinf1 的敲低则使该模型以及主要耐药的 MBT2 模型敏感。Serpinf1 的过表达与游离脂肪酸的产生增加和 CD8+细胞的激活减少有关，而奥利司他，一种减少游离脂肪酸产生的化合物，逆转了对 PD-1 治疗的耐药性。我们的结果表明，一组同基因耐药模型构成了一种有用的工具，可以模拟临床上遇到的耐药机制的异质性。
