Willemsen M, Bulgarelli J, Chauhan S K, Lereim R R, Angeli D, Grisendi G, Krebbers G, Davidson I, Kyte J A, Guidoboni M, Luiten R M, Bakker W J
Department of Dermatology and Netherlands Institute for Pigment Disorders, Amsterdam University Medical Centers, Location AMC, University of Amsterdam, Cancer Center Amsterdam, Amsterdam Institute for Immunology and Infectious Diseases, Amsterdam, The Netherlands.
Immunotherapy Cell Therapy and Biobank (ITCB) Unit, IRCCS Istituto Romagnolo per lo Studio dei Tumori (IRST) "Dino Amadori", Meldola, Italy.
Immunooncol Technol. 2024 Nov 15;24:101009. doi: 10.1016/j.iotech.2024.101009. eCollection 2024 Dec.
Tumor heterogeneity is a hurdle to effective therapy, as illustrated by the 'mixed responses' frequently seen in immunotherapy-treated patients. Previously, AXL+ tumor cells were identified to be highly resistant to targeted therapy, whereas more differentiated MITF+ tumor cells do respond to RAF and MEK inhibitors.
In this study, we analyzed tumor heterogeneity and explored the presence of the previously described AXL+ or MITF+ melanoma subpopulations in metastatic tissues by NanoString gene expression analysis, single-cell RNA sequencing and multiplex immunofluorescence. Furthermore, we analyzed how these subpopulations correlate with immunological pressure and response to immunotherapy by immunomodulating antibodies or autologous tumor lysate-loaded dendritic cell vaccination.
Our data demonstrate large interpatient variability and variable therapy-induced changes independent of the type of therapy. We identify the presence of previously described AXL+ and MITF+ subpopulations in metastatic tissues both at the mRNA level and at the protein level, and demonstrate that MITF+ melanoma cells are significantly decreased upon immunotherapy, while AXL+ melanoma cell numbers are stable. MITF+ tumor cells showed the most significant inverse correlation with CD8+ T cells. Our patient cohort also shows that immunotherapy-induced changes in the abundance of AXL+ or MITF+ tumor cells did not correlate with improved survival.
Overall, this study suggests that more differentiated MITF+ tumors are efficiently targeted by immunotherapy, while AXL+ tumor cells may be more resistant, analogous to their response to targeted therapy.
肿瘤异质性是有效治疗的一个障碍，免疫治疗患者中常见的“混合反应”就说明了这一点。此前已确定AXL+肿瘤细胞对靶向治疗具有高度抗性，而分化程度更高的MITF+肿瘤细胞对RAF和MEK抑制剂有反应。
在本研究中，我们通过NanoString基因表达分析、单细胞RNA测序和多重免疫荧光分析了肿瘤异质性，并探索了转移性组织中先前描述的AXL+或MITF+黑色素瘤亚群的存在情况。此外，我们通过免疫调节抗体或自体肿瘤裂解物负载的树突状细胞疫苗接种，分析了这些亚群与免疫压力和免疫治疗反应之间的相关性。
我们的数据表明，患者之间存在很大差异，且治疗引起的变化具有可变性，与治疗类型无关。我们在mRNA水平和蛋白质水平上均确定了转移性组织中存在先前描述的AXL+和MITF+亚群，并证明免疫治疗后MITF+黑色素瘤细胞显著减少，而AXL+黑色素瘤细胞数量保持稳定。MITF+肿瘤细胞与CD8+ T细胞呈最显著的负相关。我们的患者队列还表明，免疫治疗引起的AXL+或MITF+肿瘤细胞丰度变化与生存率提高无关。
总体而言，本研究表明，分化程度更高的MITF+肿瘤可被免疫治疗有效靶向，而AXL+肿瘤细胞可能更具抗性，这与其对靶向治疗的反应类似。
