Cohen Shvefel Sapir, Pai Joy A, Cao Yingying, Pal Lipika R, Levy Ronen, Yao Winnie, Cheng Kuoyuan, Zemanek Marie, Bartok Osnat, Weller Chen, Yin Yajie, Du Peter P, Yakubovich Elizabeta, Orr Irit, Ben-Dor Shifra, Oren Roni, Fellus-Alyagor Liat, Golani Ofra, Goliand Inna, Ranmar Dean, Savchenko Ilya, Ketrarou Nadav, Schäffer Alejandro A, Ruppin Eytan, Satpathy Ansuman T, Samuels Yardena
Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel.
Department of Pathology, Stanford University, Stanford, CA, USA.
bioRxiv. 2023 Nov 29:2023.11.29.569032. doi: 10.1101/2023.11.29.569032.
Decreased intra-tumor heterogeneity (ITH) correlates with increased patient survival and immunotherapy response. However, even highly homogenous tumors may display variability in their aggressiveness, and how immunologic-factors impinge on their aggressiveness remains understudied. Here we studied the mechanisms responsible for the immune-escape of murine tumors with low ITH. We compared the temporal growth of homogeneous, genetically-similar single-cell clones that are rejected vs. those that are not-rejected after transplantation using single-cell RNA sequencing and immunophenotyping. Non-rejected clones showed high infiltration of tumor-associated-macrophages (TAMs), lower T-cell infiltration, and increased T-cell exhaustion compared to rejected clones. Comparative analysis of rejection-associated gene expression programs, combined with CRISPR knockout screens of candidate mediators, identified (macrophage migration inhibitory factor) as a regulator of immune rejection. knockout led to smaller tumors and reversed non-rejection-associated immune composition, particularly, leading to the reduction of immunosuppressive macrophage infiltration. Finally, we validated these results in melanoma patient data.
肿瘤内异质性（ITH）降低与患者生存率提高及免疫治疗反应增强相关。然而，即使是高度同质的肿瘤在侵袭性方面也可能存在差异，而免疫因素如何影响其侵袭性仍未得到充分研究。在此，我们研究了低ITH小鼠肿瘤免疫逃逸的机制。我们使用单细胞RNA测序和免疫表型分析，比较了移植后被排斥与未被排斥的同质、基因相似的单细胞克隆的时间生长情况。与被排斥的克隆相比，未被排斥的克隆显示出肿瘤相关巨噬细胞（TAM）的高浸润、较低的T细胞浸润以及T细胞耗竭增加。对排斥相关基因表达程序的比较分析，结合候选介质的CRISPR基因敲除筛选，确定（巨噬细胞迁移抑制因子）为免疫排斥的调节因子。基因敲除导致肿瘤变小，并逆转了与未排斥相关的免疫组成，特别是导致免疫抑制性巨噬细胞浸润减少。最后，我们在黑色素瘤患者数据中验证了这些结果。
