Loss of Vhl, Trp53, and Rb1 Induces Clear Cell Renal Carcinoma in Mice Free

Biallelic inactivation of the tumor suppressor gene VHL occurs in the large majority of clear cell renal cell carcinomas (ccRCC) but is insufficient to drive ccRCC tumorigenesis. Other recurrent mutations likely cooperate with VHL inactivation to induce ccRCC. Harlander and colleagues found that human ccRCCs have recurrent copy-number changes in genes that regulate cell-cycle progression, and developed a mouse model of ccRCC in which Vhl, Trp53, and Rb1 were co-deleted in renal epithelial cells. Tumors developed in 82% of Vhl^Δ/ΔTrp53^Δ/ΔRb1^Δ/Δ mice within 25–61 weeks of gene deletion. The mouse tumors were molecularly similar to human ccRCCs and exhibited upregulation of HIF1α and HIF2α target genes, genes involved in cell-cycle progression, DNA replication, and mitosis, and genes that regulated immune responses and inflammation. Further, gene expression patterns suggested that ccRCCs in this model arise from the proximal tubule epithelial cells. However, the long latency of tumor onset indicated that additional mutations may be required for tumorigenesis. Exome sequencing of DNA from mouse ccRCCs revealed several amplifications and deletions found in both mouse and human ccRCC, including MYC amplifications. The tumors also had recurrent mutations in genes associated with the primary cilium and tumor cells displayed a reduced frequency of ciliation. Mouse tumors exhibited varying sensitivities to the ccRCC first-line therapy sunitinib; 6 of 19 tumors progressed, 3 regressed, and 10 were stable. Second-line treatment with the mTOR inhibitor everolimus promoted stable disease or regression in 18 of 23 tumors, and inhibition of HIFα signaling with acriflavine slowed tumor growth in 3 of 23 tumors. Altogether, these findings suggest that the Vhl^Δ/ΔTrp53^Δ/ΔRb1^Δ/Δ ccRCC autochthonous mouse model recapitulates a subset of the human disease and may aid in the identification of new therapies or biomarkers to predict response to therapies including HIFα inhibitors.

Harlander S, Schönenberger D, Toussaint NC, Prummer M, Catalano A, Brandt L, et al. Combined mutation in Vhl, Trp53 and Rb1 causes clear cell renal cell carcinoma in mice. Nat Med 2017 May 29 [Epub ahead of print].

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