Compound F33 emerged as the most favorable candidate, and displayed moderate inhibitory activity against Gαq/11 proteins (IC = 9.4 μM) and two UM cell lines MP41 (IC = 6.7 μM) and 92.1 (IC = 3.7 μM). Being a small molecule inhibitor of Gαq/11 proteins, F33 could effectively suppress the activation of downstream signaling pathways in a dose-dependent manner, and significantly inhibits UM in vitro.F33 represents a promising lead compound for developing therapeutics for UM by targeting Gαq/11 proteins.

We used the highly specific Gq/11 inhibitor FR900359 (FR) to elucidate signaling networks that drive proliferation, metabolic reprogramming, and dedifferentiation of UM cells...ssGSEA, unsupervised analysis, and functional studies indicated that mTORC1 and 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 2 (PFKFB2) drive metabolic reprogramming in UM cells. Together, these results identified protein kinase signaling networks driven by oncogenic Gq/11 that regulate critical aspects of UM cell biology and provide targets for therapeutic investigation.

In this study, we treated GNAQ-mutant uveal melanoma cell lines with a Gαq/11 inhibitor, YM-254890, and conducted a kinase signaling proteomic screen using multiplexed-kinase inhibitors followed by mass spectrometry...Analysis of RNA-sequencing and proteomic data showed that Gαq signaling regulates STK10 expression and MARK3 activity. Our findings suggest an involvement of STK10 and MARK3 in the Gαq/11 oncogenic pathway and prompt further investigation into the specific roles and targeting potential of these kinases in uveal melanoma.

Synergistic effects on calcium flux and cell migration are inhibited by the Gα inhibitor pertussis toxin and the Gα inhibitor YM254890, suggesting that the Gα and Gα pathways are involved in the synergy. Enhanced calcium signaling and cell migration are also observed in NCI-H23 and HeLa cells, which coexpress CXCR4 and HRH1. Taken together, our findings demonstrate an interplay between CXCR4 and HRH1, and suggest the possibility of the CXCR4-HRH1 heteromer as a potential therapeutic target for anticancer therapy.

We further demonstrate that a 2-week combination treatment of 0.3-0.4 mg/kg of YM-254890 administered by intraperitoneal injection and 25-40 mg/kg linsitinib administered by oral gavage effectively inhibits the growth of metastatic UM tumors in immunodeficient NOD scid gamma (NSG) mice and identify the IGF1 pathway as a potential resistance mechanism in response to Galphaq/11 inhibition in UM. These data suggest that the combination of Galphaq/11 and IGF1R inhibition provides a promising therapeutic strategy to treating metastatic UM.

GPCR-dependent signaling by PM-restricted wild type αq is strongly inhibited by YM, demonstrating that resistance to YM inhibition by membrane-binding mutants is specific to constitutively active αqQ209L. Together, these results indicate that changes in membrane binding impact the ability of YM to inhibit αqQ209L and suggest that YM contributes to inhibition of αqQ209L by promoting its relocalization.

Lidocaine (10 mM; a concentration within the clinically used range) activates T2R calcium responses that are inhibited by pertussis toxin, an inhibitor of G - coupled GPCRs, and by suramin, an inhibitor of G . This was distinct from the structurally-related T2R agonist denatonium, which activates calcium responses inhibited by G inhibitor YM-254890 but not pertussis toxin...Lidocaine or other T2R agonists may aid in eradication of residual cancer cells and extend time between initial surgery and reoccurrence/metastasis as an alternative or complementary therapy. With their promising effects on oral and oropharyngeal SCC cells and accessibility of the oral cavity to topically applied lidocaine gels, further work is warranted to understand the effects of bitter local anesthetics and T2R signaling in HNSCC and normal surrounding epithelia.

YM-254890 (YM) and FR-900359 (FR) have gained much attention due to their ability to inhibit constitutively active Gαq by preventing the release of GDP and thereby inhibiting GDP to GTP exchange. Using pull down techniques to determine if YM promotes an inactive conformation of the PM-restricted GαqQ209L mutants we show that both GαqQ209L and PM-restricted GαqQ209L mutants display increased binding to Gβγ and decreased binding to RGS2 upon YM treatment, suggesting that YM promotes an inactive conformation in these PM-restricted mutants in the same manner as with Gαq WT and GαqQ209L. Our studies suggest that an additional way in which YM inhibits GαqQ209L is by promoting the subcellular redistribution of constitutively active Gαq from the PM to the cytoplasm.

Thereby, the isolation and structure elucidation of novel FR analogs of low abundance is enabled. Further, we explore the antiproliferative activities of fifteen chromodepsins against uveal melanoma cell lines harboring Gq/11 mutations and characterize the major metabolite of FR formed in plasma.

All oncogenic signaling could be extinguished by the novel GNAQ/11 inhibitor YM-254890, in all UM cells with driver mutation in the Gαq subunit or the upstream receptor. Our findings highlight the GNAQ/11 → PLCβ → PKC → MAPK pathway as the central signaling axis to be suppressed pharmacologically to treat for neoplastic disorders with Gαq pathway mutations.

These data suggest that the combination of Gαq and MEK inhibition provides a promising therapeutic strategy and improved therapeutic window of broadly targeting Gαq in uveal melanoma.

In our study we identified the cyclic depsipeptide FR-900359, which is isolated from the evergreen plant Ardisia crenata as an effective inhibitor of constitutively active Gα proteins and their downstream targets. Although our data are preliminary, they might contribute to a future treatment option for patients with metastasized uveal melanoma.

Here we found that YM-254890, a cyclic depsipeptide, inhibited downstream signaling induced by GNAQQ209L and GNA11Q209L, but not GNA14Q205L, GNA15Q212L and GNASQ227L in 293T cells, confirming that it is a GNAQ/11-specific inhibitor...Concordantly, an engineered GNA11 with the two mutations in cis was resistant to the compound. Our data suggest that targeting mutant GNAQ/11 is promising but will require combinatorial targeting of EDNR signaling and possibly other pathways to reach maximal clinical efficacy.