Abstract 1931: Targeting YAP1/TEAD signaling re-sensitizes MAPK/ERK pathway inhibitors in KRAS- driven cancer cells

Abstract Many TEAD small-molecule inhibitors (SMIs) have recently reported initial clinical evaluations on Hippo-mutated cancer types. Several studies have demonstrated that activation of the YAP1/TEAD transcriptional complex via a Hippo-independent manner can drive resistance to MAPK/ERK pathway inhibitors. Here, we elucidated the potential mechanism of TEAD inhibition overcoming MAPK/ERK pathway resistance with a TEAD SMI (hereafter abbreviated as TEADi). Firstly, the MoA of TEADi was validated in Hippo-mutated cells. TEADi inhibited cell growth of Hippo-mutated cancer cell lines NCI-H226 and NCI-H2052 but not that of MKN45, a YAP1-deletion cell line. Co-IP and qRT-PCR results demonstrated that TEADi disrupted the interaction between YAP1 and TEAD, and thus markedly repressed the expression of CTGF and CYR61, two downstream targets of YAP1/TEAD, in NCI-H226 cells. Secondly, we hypothesized that hyper-activation of TEAD confers resistance to KRAS mutant cancer types. To test this hypothesis, we generated two resistant cell lines. One is KARS G12C inhibitor Sotorasib-resistant NCI-H358 (NCI-H358-R). The other is MEK inhibitor Trametinib-resistant HCT116 (HCT116-R). Immunofluoresence assay showed that YAP1 nucleus translocation was enhanced in both resistant cells (NCI-H358-R and HCT116-R), but not in their parental counterparts (NCI-H358-P and HCT116-P). The enhanced YAP1 nucleus translocation resulted in increased transcription activities of TEAD in both resistant cells, as illustrated by luciferase reporter assay. Accordingly, CTGF and CYR61 were observed upregulated in both resistant cells. The above data indicate that YAP1/TEAD mediated-transactivation plays a role in MAPK pathway resistance. Indeed, TEADi treatment alone displayed substantial difference in cell growth inhibition between parental and resistant cell lines in both NCI-H358 and HCT116, further confirming that the resistant cells are more dependent on YAP1/TEAD signaling. Finally, we evaluated the combinational efficacies of TEADi and MAPK/ERK pathway inhibitors in the resistant cells. It was observed that addition of TEADi could significantly restore the response of NCI-H358-R and HCT116-R to Sotorasib and Trametinib, respectively. Mechanistically, TEADi efficiently suppressed TEAD transcriptional activities and subsequently the expression of CTGF and CYR61 in both resistant cells. Moreover, TEADi had almost no impact on ERK phosphorylation in either of the resistant cells, suggesting that re-sensitization of MAPK/ERK pathway inhibitors by TEADi is independent of primary onco-genetic signaling pathway. Taken together, our study demonstrates that inhibition of YAP1/TEAD signaling would be an efficient approach to overcome resistance to MAPK/ERK pathway inhibitors in the patients carrying KRAS mutations, and provides the scientific basis for development of combination therapy strategies. Citation Format: Xianwen Yang, Guiping Li, Peiling Ren, Xiaoyun Shi, Ying Yu, Baoyu Hao, Pan Wang, Min Cheng, Guangxiu Dai. Targeting YAP1/TEAD signaling re-sensitizes MAPK/ERK pathway inhibitors in KRAS- driven cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1931.