Lelliott Emily J, Sheppard Karen E, McArthur Grant A
Cancer Research Division, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia.
Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, VIC, Australia.
NPJ Precis Oncol. 2022 Apr 20;6(1):26. doi: 10.1038/s41698-022-00273-9.
CDK4/6 inhibitors (CDK4/6i) were developed as a cancer therapeutic on the basis of their tumor-intrinsic cytostatic potential, but have since demonstrated profound activity as immunomodulatory agents. While currently approved to treat hormone receptor-positive breast cancer, these inhibitors are under investigation in clinical trials as treatments for a range of cancer types, including melanoma. Melanoma is a highly immunogenic cancer, and has always been situated at the forefront of cancer immunotherapy development. Recent revelations into the immunotherapeutic activity of CDK4/6i, therefore, have significant implications for the utility of these agents as melanoma therapies. In recent studies, we and others have proven the immunomodulatory effects of CDK4/6i to be multifaceted and complex. Among the most notable effects, CDK4/6 inhibition induces transcriptional reprogramming in both tumor cells and immune cells to enhance tumor cell immunogenicity, promote an immune-rich tumor microenvironment, and skew T cell differentiation into a stem-like phenotype that is more amenable to immune checkpoint inhibition. However, in some contexts, the specific immunomodulatory effects of CDK4/6i may impinge on anti-tumor immunity. For example, CDK4/6 inhibition restricts optimal T cells expansion, and when used in combination with BRAF/MEK-targeted therapies, depletes immune-potentiating myeloid subsets from the tumor microenvironment. We propose that such effects, both positive and negative, may be mitigated or exacerbated by altering the CDK4/6i dosing regimen. Here, we discuss what the most recent insights mean for clinical trial design, and propose clinical considerations and strategies that may exploit the full immunotherapeutic potential of CDK4/6 inhibitors.
细胞周期蛋白依赖性激酶4/6抑制剂(CDK4/6i)基于其肿瘤内在的细胞生长抑制潜力被开发为一种癌症治疗药物,但后来已证明其作为免疫调节药物具有显著活性。虽然目前被批准用于治疗激素受体阳性乳腺癌,但这些抑制剂正在多项临床试验中接受研究,作为包括黑色素瘤在内的一系列癌症类型的治疗方法。黑色素瘤是一种高度免疫原性的癌症,一直处于癌症免疫治疗发展的前沿。因此,最近关于CDK4/6i免疫治疗活性的新发现,对于这些药物作为黑色素瘤治疗方法的效用具有重大意义。在最近的研究中,我们和其他人已经证明CDK4/6i的免疫调节作用是多方面且复杂的。其中最显著的作用包括,CDK4/6抑制在肿瘤细胞和免疫细胞中诱导转录重编程,以增强肿瘤细胞的免疫原性,促进富含免疫细胞的肿瘤微环境,并使T细胞分化偏向更易于接受免疫检查点抑制的干细胞样表型。然而,在某些情况下,CDK4/6i的特定免疫调节作用可能会影响抗肿瘤免疫。例如,CDK4/6抑制会限制T细胞的最佳扩增,并且当与BRAF/MEK靶向疗法联合使用时,会从肿瘤微环境中耗尽具有免疫增强作用的髓系亚群。我们认为,通过改变CDK4/6i给药方案,这些正负效应可能会得到缓解或加剧。在此,我们讨论这些最新见解对临床试验设计的意义,并提出可能充分发挥CDK4/6抑制剂免疫治疗潜力的临床考虑因素和策略。