Shirole Nitin H, Kesar Devishi, Lee Yenarae, Goodale Amy, Syamala Sudeepa, Kukreja Shweta, Li Rong, Qiu Xintao, Yu Wenyu, Goldman Seth, Cejas Paloma, Long Henry W, Adelman Karen, Doench John G, Sellers William R, Kaelin William G
Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts.
Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts.
Cancer Discov. 2025 Jul 3;15(7):1484-1504. doi: 10.1158/2159-8290.CD-24-1378.
Inactivation of the VHL gene stabilizes HIF2α, which drives clear-cell renal cell carcinoma (ccRCC). The HIF2α inhibitor belzutifan is approved for ccRCC treatment, but de novo and acquired resistance are common. HIF2α, bound to ARNT, transcriptionally activates many genes. We performed CRISPR-mediated gene activation screens in HIF2α-dependent ccRCC lines treated with a belzutifan analog to identify HIF2α-responsive genes that confer cell-autonomous belzutifan resistance when not downregulated. Sustaining the expression of the HIF2α target gene CCND1, encoding cyclin D1, promoted HIF2α independence/belzutifan resistance. This activity requires CDK4/6 activation by cyclin D1 but is not solely due to phosphorylation of the canonical cyclin D1 target, pRB. Indeed, ccRCC lines lacking all three pRB family members remained at least partially HIF2α-dependent. In this context, however, a kinase-defective cyclin D1 variant partially overrode belzutifan's antiproliferative effects, suggesting that ccRCC promotion by cyclin D1 requires the phosphorylation of pRB paralogs and one or more kinase-independent cyclin D1 activities.
We discovered that cyclin D1 is the key target of HIF2 driving the cell-autonomous proliferation of VHL-mutant kidney cancers and that cyclin D1 has targets beyond pRB in this setting. These findings have implications for treating kidney cancer with HIF2 inhibitors, alone or in combination with CDK4/6 inhibitors.
VHL基因的失活会使HIF2α稳定，从而驱动透明细胞肾细胞癌（ccRCC）。HIF2α抑制剂belzutifan已被批准用于ccRCC的治疗，但原发性和获得性耐药很常见。与ARNT结合的HIF2α会转录激活许多基因。我们在用belzutifan类似物处理的HIF2α依赖性ccRCC细胞系中进行了CRISPR介导的基因激活筛选，以鉴定在不被下调时赋予细胞自主belzutifan耐药性的HIF2α反应性基因。维持HIF2α靶基因CCND1（编码细胞周期蛋白D1）的表达可促进HIF2α独立性/ belzutifan耐药性。这种活性需要细胞周期蛋白D1激活CDK4/6，但不仅仅是由于经典细胞周期蛋白D1靶标pRB的磷酸化。实际上，缺乏所有三个pRB家族成员的ccRCC细胞系至少部分仍依赖HIF2α。然而，在这种情况下，一种激酶缺陷型细胞周期蛋白D1变体部分克服了belzutifan的抗增殖作用，这表明细胞周期蛋白D1促进ccRCC需要pRB旁系同源物的磷酸化以及一种或多种激酶非依赖性细胞周期蛋白D1活性。
我们发现细胞周期蛋白D1是HIF2驱动VHL突变型肾癌的细胞自主增殖的关键靶标，并且在这种情况下细胞周期蛋白D1的靶标超出了pRB。这些发现对单独或与CDK4/6抑制剂联合使用HIF2抑制剂治疗肾癌具有重要意义。
