Single-Cell Transcriptome Analysis Guides Tailored Combinatorial Therapeutics In Refractory Kidney Cancer

Metastatic renal cell carcinoma (mRCC) evolves from primary RCC (pRCC) and harbors multiple subpopulations with distinct molecular and phenotypic features. Such underlying intratumoral heterogeneity (ITH) imposes difficulties in designing marker-based clinical trials because targeted mono-therapy eliminates a specific subpopulation of tumor cells while leaving others unharmed. Accordingly, a rational combination strategy that minimizes the survival of the drug-resistant subpopulation in a given heterogeneous tumor is essential for long-term therapeutic efficacy. Here, we examined the ITH of a paired mRCC and pRCC using single-cell mRNA sequencing (scRNA-seq) to identify specific tumor cell populations with drug target pathway activation. From the single cell expression profiles, we found the highly activated status of the EGFR and Src signaling pathways in the mRCC compared to the pRCC, with supporting in vitro high-throughput drug screening results. Distinct features of intratumoral expression variability across mRCC single cells that were masked in the bulk measurement prompted us to test the co-targeting strategy for the EGFR and Src pathways with increased likelihood for complete response. This combinatorial strategy showed significantly better treatment effects on mRCC-derived xenograft platforms in vitro and in vivo than monotherapies. Taken together, our findings show clinical implications of scRNA-seq in designing effective treatment regimens for overcoming treatment failure to conventional monotherapies, and also provide novel insights to the unmet clinical needs in effective personalized treatments. Citation Format: Kyu-Tae Kim, Hye Won Lee, Hae-Ock Lee, Hye Jin Song, Da Eun Jeong, Sang Shin, Hyunho Kim, Yoojin Shin, Do-Hyun Nam, Byong Chang Jeong, David G. Kirsch, Kyeung Min Joo, Woong-Yang Park. Single-cell transcriptome analysis guides tailored combinatorial therapeutics in refractory kidney cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 165.