Combining the Tyrosine Kinase Inhibitor Cabozantinib and the mTORC1/2 Inhibitor Sapanisertib Blocks ERK Pathway Activity and Suppresses Tumor Growth in Renal Cell Carcinoma.

Current treatment approaches for renal cell carcinoma (RCC) face challenges in achieving durable tumor responses due to tumor heterogeneity and drug resistance. Combination therapies that leverage tumor molecular profiles could offer an avenue for enhancing treatment efficacy and addressing the limitations of current therapies. To identify effective strategies for treating RCC, we selected ten drugs guided by tumor biology to test in six RCC patient-derived xenograft (PDX) models. The multitargeted tyrosine kinase inhibitor (TKI) cabozantinib and mTORC1/2 inhibitor sapanisertib emerged as the most effective drugs, particularly when combined. The combination demonstrated favorable tolerability and inhibited tumor growth or induced tumor regression in all models, including two from patients who experienced treatment failure with FDA-approved TKI and immunotherapy combinations. In cabozantinib-treated samples, imaging analysis revealed a significant reduction in vascular density, and single-nucleus RNA sequencing (snRNA-seq) analysis indicated a decreased proportion of endothelial cells in the tumors. SnRNA-seq data further identified a tumor subpopulation enriched with cell-cycle activity that exhibited heightened sensitivity to the cabozantinib and sapanisertib combination. Conversely, activation of the epithelial-mesenchymal transition pathway, detected at the protein level, was associated with drug resistance in residual tumors following combination treatment. The combination effectively restrained ERK phosphorylation and reduced expression of ERK downstream transcription factors and their target genes implicated in cell-cycle control and apoptosis. This study highlights the potential of the cabozantinib plus sapanisertib combination as a promising treatment approach for patients with RCC, particularly those whose tumors progressed on immune checkpoint inhibitors and other TKIs.

The molecular-guided therapeutic strategy of combining cabozantinib and sapanisertib restrains ERK activity to effectively suppress growth of renal cell carcinomas, including those unresponsive to immune checkpoint inhibitors.

Cancer research. 2023 Dec 15 [Epub]

Yige Wu, Siqi Chen, Xiaolu Yang, Kazuhito Sato, Preet Lal, Yuefan Wang, Andrew T Shinkle, Michael C Wendl, Tina M Primeau, Yanyan Zhao, Alanna Gould, Hua Sun, Jacqueline L Mudd, Jeremy Hoog, R Jay Mashl, Matthew A Wyczalkowski, Chia-Kuei Mo, Ruiyang Liu, John M Herndon, Sherri R Davies, Di Liu, Xi Ding, Yvonne A Evrard, Bryan E Welm, David Lum, Mei Yee Koh, Alana L Welm, Jeffrey H Chuang, Jeffrey A Moscow, Funda Meric-Bernstam, Ramaswamy Govindan, Shunqiang Li, James Hsieh, Ryan C Fields, Kian-Huat Lim, Cynthia X Ma, Hui Zhang, Li Ding, Feng Chen

Department of Medicine, Washington University in St. Louis, St. Louis, Missouri., Department of Pathology, Johns Hopkins University, Baltimore, Maryland., Siteman Cancer Center, Washington University in St. Louis, St. Louis, Missouri., Frederick National Laboratory for Cancer Research, Frederick, Maryland., Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah., The Jackson Laboratory for Genomic Medicine, Farmington, Connecticut., Investigational Drug Branch, National Cancer Institute, Bethesda, Maryland., The University of Texas MD Anderson Cancer Center, Houston, Texas., Department of Genetics, Washington University in St. Louis, St. Louis, Missouri.