Ravoxertinib

Lenvatinib serves as a first-line systemic therapy for advanced hepatocellular carcinoma (HCC), yet the development of resistance poses a major clinical challenge. The purpose of this study is to investigate the mechanisms underlying lenvatinib resistance in HCC and identify potential interventions. We established lenvatinib-resistant HuH7 and Hep3B cell lines and conducted in vitro, bioinformatics, and biochemical assays to explore and validate the mechanisms underlying acquired resistance to lenvatinib in HCC. Additionally, cellular xenograft models of lenvatinib-resistant HCC were utilized to assess tumor responses to a novel drug treatment regimen. Our findings revealed a shift from suppression to activation in the expression of p-ERK1/2 and Cyclin D1 in HCC cells as they transitioned from sensitivity to resistance to lenvatinib. Furthermore, we demonstrated that targeting ERK1/2 with ravoxertinib (an ERK1/2 inhibitor) could significantly enhance the sensitivity of resistant HCC cells to lenvatinib therapy. Through transcriptome data analysis and experimental validation, we identified amphiregulin (AREG), induced autocrinely by lenvatinib, as a critical mediator that activates the EGFR-ERK1/2 signaling pathway, leading to increased Cyclin D1 expression in HCC cells. Mechanistically, lenvatinib promotes aryl hydrocarbon receptor (AHR) nuclear translocation, directly activating AREG transcription. Using in vivo models, we further confirmed that inhibiting ERK1/2 with ravoxertinib or AHR with CH-223191 (an AHR inhibitor) could overcome lenvatinib resistance in HCC. Overall, lenvatinib-induced AHR activation promotes AREG expression, which subsequently facilitates the acquisition of drug resistance in HCC via the EGFR-ERK1/2-CyclinD1 signaling axis. Targeting ERK1/2 and AHR effectively improved the response to lenvatinib treatment in resistant HCC.

Dysregulation of the phosphatidylinositol 3-kinase (PI3K) pathway is a key contributor to cancer, making PI3K inhibitors a promising approach for targeted therapy. The selectivity of available inhibitors varies across different PI3K isoforms. Alpelisib and inavolisib are selective for the α-isoform, while duvelisib targets the δ- and γ-isoforms, and copanlisib is a pan-PI3K inhibitor, active against all isoforms. This study investigated the activity of these four PI3K inhibitors in combination with other targeted agents using multi-cell type tumor spheroids composed of 60% malignant cells, 25% endothelial cells, and 15% mesenchymal stem cells. Twenty-nine tumor spheroid models were evaluated, including twenty-six patient-derived cancer cell lines from the NCI Patient-Derived Models Repository and three established cell lines from the NCI-60 human tumor cell line panel. Additive and/or synergistic effects were observed with alpelisib or inavolisib or copanlisib in combination with a RAS/MEK/ERK pathway inhibitor, either selumetinib (MEK), ravoxertinib (ERK 1/2), or tovorafenib (DAY101, RAF). Combinations of each of these three PI3K inhibitors with the KRAS mutation specific inhibitors MTRX1133 (KRAS G12D) or sotorasib (KRAS G12C) had selective activity in cell lines harboring the corresponding target. Lastly, combination effects were observed from vertical inhibition of the PI3K/AKT/mTOR pathway with a PI3K inhibitor in combination with either the mTORC1/2 inhibitor sapanisertib or an AKT inhibitor, ipatasertib or afuresertib.