ravoxertinib (RG7842)

Although ravoxertinib alone showed limited antitumor activity, its combination with BRAFi/MEKi yielded substantial benefits, especially in chronic settings. These findings suggest that combinatorial regimens incorporating ERK inhibitors represent a promising therapeutic strategy for BRAF-mutant melanoma.

The ERK inhibitor GDC-0994 exhibited significant synergistic effects with the AR inhibitor bicalutamide. Specifically, the combination therapy inhibits FOXC2-driven EMT and induces ferroptosis via the FOXC2-Hippo signaling axis, suppressing tumor proliferation, migration, and invasion. In summary, this study uncovers the value of AR/ERK co-targeting in TNBC, which might potentiate the development of novel targeted therapeutic strategies in TNBC.

The combination of ipatasertib with the MEK inhibitor selumetinib or the ERK inhibitor ravoxertinib resulted in additive and/or greater-than-additive cytotoxicity in approximately half the cell lines screened. The V600E mutation-specific BRAF inhibitor vemurafenib and the KRAS G12C selective inhibitor sotorasib in combination with ipatasertib were active in the eight BRAF V600E and four KRAS G12C mutant-containing cell lines, respectively. Vertical inhibition of the PI3K/AKT/mTOR pathway with the mTORC1/2 kinase inhibitor sapanisertib demonstrated additive and/or greater-than-additive effects in multiple cell lines. In early experiments, there was a correlation between the response to ipatasertib and selumetinib in two patient-derived tumor lines grown as mct-spheroids and the corresponding patient-derived xenografts. All data are accessible via the PubChem BioAssay public database.

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. 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.

This study provided potential prognostic biomarkers for LUAD and might facilitate the development of effective immunotherapy strategies for LUAD patients.

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.

The ERK-inhibitor GDC-0994 blocked phosphorylation of MEK/ERK and suppressed TGM2 and MMP7. TGM2 communicates with MMP7 in colon cancer cells forces cell migration and invasion by the MEK/ERK signaling pathway and triggers EMT. Inhibiting TGM2 could thus offer new therapeutic options to treat patients with colon cancer, particularly to prevent metastatic progression.

Finally, we discovered that AIBP could control the MAPK signaling pathway-involved genes expression, including P-MEK, MEK, c-Myc, P-ERK1/2, and ERK1/2, and that GDC-0994, a specific ERK1/2 inhibitor, could suppress the AIBP overexpression induced cell migration and proliferation abilities. These findings demonstrated that the ERK/MAPK signaling pathway might be stimulated by AIBP in HCC tissues, leading to increased cell invasion, migration, and proliferation. It was hypothesized that AIBP might act as a useful prognostic and diagnostic marker for HCC.

Moreover, GDC-0994 selectively inhibited tumor growth in a BRAF mutant xenograft mice model. Our findings demonstrate a BRAF mutation-dependent anti-tumor effect of GDC-0994 and provide a rational strategy for patient selection for ERK1/2 inhibitor treatment.

Of great interest, tetrandrine stabilizes DR4/DR5 protein via impairing ubiquitination-mediated protein degradation, thereby allowing a synergy with MAPK inhibition in inducing apoptosis in KRAS-mutant PDAC. Our findings identify a new combinatorial approach for treating KRAS-mutant PDAC and highlight the role of TRAIL-DR4/DR5 axis in dictating the therapeutic outcome in KRAS-mutant PDAC.

Notably, several proteins have previously been observed in pancreatic cancer cells with intrinsic resistance to the combined kinase inhibition treatment, suggesting a proteomic signature. We also found that resistant cells are sensitive to small molecule drugs ERK inhibitor GDC-0994, S6K1 inhibitor DG2 and statins.

The ravoxertinib-dependent inhibition of Erk1/2 signaling led to the decrease in erastin efficacy due to the effect on ROS production and the upregulation of ROS scavengers SOD1 and SOD2, resulting in repressed lipid peroxidation. Therefore, it was concluded that the erastin-dependent activation of ferroptosis seems to be a promising approach which can be further developed as an additional strategy for the treatment of HNSCC. As ferroptosis induction via erastin is strongly dependent on the expression of Erk1/2, this MAP kinase can be considered as a predictor for cancer cells' response to erastin.