背景:将白介素-2(IL-2)与放疗(RT)和免疫检查点阻断(ICB)相结合已成为解决ICB耐药性的有希望的方法。然而,常规IL-2细胞因子治疗因其短暂的半衰期和不良反应而面临限制.RDB1462,Nemvaleukinalfa的小鼠直系同源,是具有中间亲和力的工程改造的IL-2,其选择性地刺激抗肿瘤CD8T和NK细胞,同时限制调节性T细胞扩增。本研究旨在评估RDB1462,RT,和小鼠肿瘤模型中的抗PD1。
方法:使用344SQ亲本和344SQ抗PD1耐药细胞系建立两个双侧肺腺癌小鼠模型。原发性肿瘤用RT治疗,和继发性肿瘤被观察到的abscopal效应的证据。我们通过流式细胞术进行免疫表型分析,使用NanoString分析了770个免疫相关基因,并进行T细胞受体(TCR)库分析。通过23-plex试剂盒分析血清促炎细胞因子标志物。
结果:与天然IL-2(RDB1475)相比,RDB1462表现出优异的全身抗肿瘤反应,归因,至少在某种程度上,与后者一起增加CD4和CD8T细胞的水平。我们的研究结果表明,与单一疗法对照相比,原发性和继发性肿瘤体积显著减少,在RDB1462联合RT的不同给药方案中观察到一些变异性。基于血液和肿瘤组织的流式细胞术表型分析显示效应记忆CD8和CD4T细胞增加,免疫抑制细胞减少,伴随IL-2,IFN-γ显着增加,和GM-CSF水平在组合组中。转录组分析和TCR测序揭示了双重组合的有利基因表达和T细胞库模式。此外,整合抗PD1治疗与RT和RDB1462进一步减少原发性和继发性肿瘤体积,延长生存期,肺转移减少。免疫细胞谱的观察表明,使用递增剂量的RDB1462的RT显著降低肿瘤生长并增加肿瘤特异性免疫细胞群。
结论:添加Nemvaleukin治疗可能会增强对单独RT和与抗PD1联合的反应。
BACKGROUND: Combining interleukin-2 (IL-2) with radiotherapy (RT) and immune checkpoint blockade (ICB) has emerged as a promising approach to address ICB resistance. However, conventional IL-2 cytokine therapy faces constraints owing to its brief half-life and adverse effects. RDB 1462, the mouse ortholog of Nemvaleukin alfa, is an engineered IL-2 with an intermediate affinity that selectively stimulates antitumor CD8 T and NK cells while limiting regulatory T cell expansion. This study aimed to evaluate the antitumor activity and mechanism of action of the combination of RDB 1462, RT, and anti-PD1 in mouse tumor models.
METHODS: Two bilateral lung adenocarcinoma murine models were established using 344SQ-Parental and 344SQ anti-PD1-resistant cell lines. Primary tumors were treated with RT, and secondary tumors were observed for evidence of abscopal effects. We performed immune phenotyping by flow cytometry, analyzed 770 immune-related genes using NanoString, and performed T cell receptor (TCR) repertoire analysis. Serum pro-inflammatory cytokine markers were analyzed by 23-plex kit.
RESULTS: Compared to native IL-2 (RDB 1475), RDB 1462 demonstrated superior systemic antitumoral responses, attributable, at least in part, to augmented levels of CD4 and CD8 T cells with the latter. Our findings reveal substantial reductions in primary and secondary tumor volumes compared to monotherapy controls, with some variability observed among different dosing schedules of RDB 1462 combined with RT. Blood and tumor tissue-based flow cytometric phenotyping reveals an increase in effector memory CD8 and CD4 T cells and a decrease in immunosuppressive cells accompanied by a significant increase in IL-2, IFN-γ, and GM-CSF levels in the combination group. Transcriptomic profiling and TCR sequencing reveal favorable gene expression and T cell repertoire patterns with the dual combination. Furthermore, integrating anti-PD1 therapy with RT and RDB 1462 further reduced primary and secondary tumor volumes, prolonged survival, and decreased lung metastasis. Observations of immune cell profiles indicated that RT with escalating doses of RDB 1462 significantly reduced tumor growth and increased tumor-specific immune cell populations.
CONCLUSIONS: The addition of Nemvaleukin therapy may enhance responses to RT alone and in combination with anti-PD1.