CD133+PD-L1+ cancer cells confer resistance to adoptively transferred engineered macrophage-based therapy in melanoma.. CD133+PD-L1+ cancer cells confer resistance to adoptively transferred engineered macrophage-based therapy in melanoma.

Adoptive transfer of genetically or nanoparticle-engineered macrophages represents a promising cell therapy modality for treatment of solid tumor. However, the therapeutic efficacy is suboptimal without achieving a complete tumor regression, and the underlying mechanism remains elusive. Here, we discover a subpopulation of cancer cells with upregulated CD133 and programmed death-ligand 1 in mouse melanoma, resistant to the phagocytosis by the transferred macrophages. Compared to the CD133-PD-L1- cancer cells, the CD133+PD-L1+ cancer cells express higher transforming growth factor-β signaling molecules to foster a resistant tumor niche, that restricts the trafficking of the transferred macrophages by stiffened extracellular matrix, and inhibits their cell-killing capability by immunosuppressive factors. The CD133+PD-L1+ cancer cells exhibit tumorigenic potential. The CD133+PD-L1+ cells are further identified in the clinically metastatic melanoma. Hyperthermia reverses the resistance of CD133+PD-L1+ cancer cells through upregulating the ‘eat me’ signal calreticulin, significantly improving the efficacy of adoptive macrophage therapy. Our findings demonstrate the mechanism of resistance to adoptive macrophage therapy, and provide a de novo strategy to counteract the resistance. Overall design: The bulk RNA-seq samples in this study included the in vitro cultured NPs-hMΦ and Un-hMΦ; B16F10 tumor tissues following different treatment; the sorted CD133+ and CD133- B16F10 cancer cells; and the sorted GFP+CD133+PD-L1+ and GFP+CD133-PD-L1- cancer cells from the relapsed B16F10 tumors.

经基因工程或纳米颗粒工程化改造的巨噬细胞过继转移，是一种颇具前景的实体瘤细胞治疗策略。然而，该疗法的治疗效果欠佳，无法实现完全的肿瘤消退，其背后的潜在机制仍有待阐明。本研究在小鼠黑色素瘤中发现了一类CD133与PD-L1（programmed death-ligand 1）均上调的癌细胞亚群，该亚群可抵抗过继转移巨噬细胞的吞噬作用。相较于CD133-PD-L1-癌细胞，CD133+PD-L1+癌细胞可高表达转化生长因子-β（transforming growth factor-β）信号分子，以构建耐药性肿瘤微环境：该微环境通过硬化细胞外基质限制过继转移巨噬细胞的募集，并通过免疫抑制因子削弱巨噬细胞的杀瘤能力。CD133+PD-L1+癌细胞具备致瘤潜能。研究人员还在临床转移性黑色素瘤样本中鉴定出了CD133+PD-L1+癌细胞亚群。热疗可通过上调"eat me"信号分子钙网蛋白（calreticulin），逆转CD133+PD-L1+癌细胞的耐药性，从而显著提升巨噬细胞过继治疗的疗效。本研究阐明了巨噬细胞过继治疗耐药性的潜在机制，并提出了一种对抗该耐药性的全新策略。整体实验设计：本研究的批量RNA测序样本涵盖：体外培养的纳米颗粒工程化巨噬细胞（NPs-hMΦ）与未工程化巨噬细胞（Un-hMΦ）、经不同方案处理的B16F10肿瘤组织、分选得到的CD133+与CD133-B16F10癌细胞，以及从复发B16F10肿瘤中分选得到的GFP+CD133+PD-L1+与GFP+CD133-PD-L1-癌细胞。