Dataset Information

BI-3406, a Potent and Selective SOS1-KRAS Interaction Inhibitor, Is Effective in KRAS-Driven Cancers through Combined MEK Inhibition.

ABSTRACT: KRAS is the most frequently mutated driver of pancreatic, colorectal, and non-small cell lung cancers. Direct KRAS blockade has proved challenging, and inhibition of a key downstream effector pathway, the RAF-MEK-ERK cascade, has shown limited success because of activation of feedback networks that keep the pathway in check. We hypothesized that inhibiting SOS1, a KRAS activator and important feedback node, represents an effective approach to treat KRAS-driven cancers. We report the discovery of a highly potent, selective, and orally bioavailable small-molecule SOS1 inhibitor, BI-3406, that binds to the catalytic domain of SOS1, thereby preventing the interaction with KRAS. BI-3406 reduces formation of GTP-loaded RAS and limits cellular proliferation of a broad range of KRAS-driven cancers. Importantly, BI-3406 attenuates feedback reactivation induced by MEK inhibitors and thereby enhances sensitivity of KRAS-dependent cancers to MEK inhibition. Combined SOS1 and MEK inhibition represents a novel and effective therapeutic concept to address KRAS-driven tumors. SIGNIFICANCE: To date, there are no effective targeted pan-KRAS therapies. In-depth characterization of BI-3406 activity and identification of MEK inhibitors as effective combination partners provide an attractive therapeutic concept for the majority of KRAS-mutant cancers, including those fueled by the most prevalent mutant KRAS oncoproteins, G12D, G12V, G12C, and G13D.See related commentary by Zhao et al., p. 17.This article is highlighted in the In This Issue feature, p. 1.

SUBMITTER: Hofmann MH

PROVIDER: S-EPMC7892644 | biostudies-literature | 2021 Jan

REPOSITORIES: biostudies-literature

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BI-3406, a Potent and Selective SOS1-KRAS Interaction Inhibitor, Is Effective in KRAS-Driven Cancers through Combined MEK Inhibition.

Hofmann Marco H MH Gmachl Michael M Ramharter Juergen J Savarese Fabio F Gerlach Daniel D Marszalek Joseph R JR Sanderson Michael P MP Kessler Dirk D Trapani Francesca F Arnhof Heribert H Rumpel Klaus K Botesteanu Dana-Adriana DA Ettmayer Peter P Gerstberger Thomas T Kofink Christiane C Wunberg Tobias T Zoephel Andreas A Fu Szu-Chin SC Teh Jessica L JL Böttcher Jark J Pototschnig Nikolai N Schachinger Franziska F Schipany Katharina K Lieb Simone S Vellano Christopher P CP O'Connell Jonathan C JC Mendes Rachel L RL Moll Jurgen J Petronczki Mark M Heffernan Timothy P TP Pearson Mark M McConnell Darryl B DB Kraut Norbert N

Cancer discovery 20200819 1

<i>KRAS</i> is the most frequently mutated driver of pancreatic, colorectal, and non-small cell lung cancers. Direct KRAS blockade has proved challenging, and inhibition of a key downstream effector pathway, the RAF-MEK-ERK cascade, has shown limited success because of activation of feedback networks that keep the pathway in check. We hypothesized that inhibiting SOS1, a KRAS activator and important feedback node, represents an effective approach to treat KRAS-driven cancers. We report the disco ...[more]

PMID: 32816843

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Project description:NSD2, through generation of the epigenetic modification histone H3 di-methylated at lysine 36 (H3K36me2), is a candidate convergent downstream effector of oncogenic KRAS-signaling. However, whether NSD2 targeting represents a therapeutic vulnerability of KRAS-driven cancers is unknown. Here, we characterize a first-in-class, clinical grade small molecule catalytic NSD2 inhibitor (NSD2i) series and find pharmacological targeting of NSD2 constitutes an epigenetic dependency with broad therapeutic efficacy in KRAS-driven pre-clinical cancer models. NSD2i inhibits NSD2 potently, with single digit nM IC50 values, and shows high selectively for NSD2 versus NSD1, NSD3, and other similar enzymes. Structural analyses reveal the molecular basis of NSD2i specificity for NSD2, which includes S-adenosylmethionine (SAM)-competitive binding and catalytic disruption via a dual-channel obstruction mechanism. Proteo-epigenomic and single cell strategies in pancreatic ductal adenocarcinoma (PDAC) and lung adenocarcinoma (LUAD) samples support a model in which durable NSD2i exposure reverses H3K36me2-driven pathologic chromatin plasticity, re-establishing silencing at H3K27me3-legacy loci to curtail KRAS-regulated and oncogenic-associated gene expression programs. Accordingly, NSD2i treatment inhibits PDAC and LUAD cell viability and patient-derived xenograft tumor growth. Further, NSD2 inhibition, which is well tolerated in vivo, is equally effective as KRAS inhibition (sotorasib) treatment in prolonging survival in advanced stage autochthonous KRASG12C-driven PDAC and LUAD mouse tumor models. Moreover, in these models, NSD2 inhibition and sotorasib co-treatment synergize to confer sustained survival with extensive tumor nodule regression and elimination. Together, our work uncovers targeting of the NSD2-H3K36me2 axis as an actionable vulnerability in KRAS-driven cancers and provides a mechanistic rationale for testing NSD2i-KRAS inhibition combination therapies in the clinic.

Project description:BackgroundOver half of colorectal cancers (CRCs) are hard-wired to RAS/RAF/MEK/ERK pathway oncogenic signaling. However, the promise of targeted therapeutic inhibitors, has been tempered by disappointing clinical activity, likely due to complex resistance mechanisms that are not well understood. This study aims to investigate MEK inhibitor-associated resistance signaling and identify subpopulation(s) of CRC patients who may be sensitive to biomarker-driven drug combination(s).MethodsWe classified 2250 primary and metastatic human CRC tumors by consensus molecular subtypes (CMS). For each tumor, we generated multiple gene expression signature scores measuring MEK pathway activation, MEKi "bypass" resistance, SRC activation, dasatinib sensitivity, EMT, PC1, Hu-Lgr5-ISC, Hu-EphB2-ISC, Hu-Late TA, Hu-Proliferation, and WNT activity. We carried out correlation, survival and other bioinformatic analyses. Validation analyses were performed in two independent publicly available CRC tumor datasets (n = 585 and n = 677) and a CRC cell line dataset (n = 154).ResultsHere we report a central role of SRC in mediating "bypass"-resistance to MEK inhibition (MEKi), primarily in cancer stem cells (CSCs). Our integrated and comprehensive gene expression signature analyses in 2250 CRC tumors reveal that MEKi-resistance is strikingly-correlated with SRC activation (Spearman P < 10-320), which is similarly associated with EMT (epithelial to mesenchymal transition), regional metastasis and disease recurrence with poor prognosis. Deeper analysis shows that both MEKi-resistance and SRC activation are preferentially associated with a mesenchymal CSC phenotype. This association is validated in additional independent CRC tumor and cell lines datasets. The CMS classification analysis demonstrates the strikingly-distinct associations of CMS1-4 subtypes with the MEKi-resistance and SRC activation. Importantly, MEKi + SRCi sensitivities are predicted to occur predominantly in the KRAS mutant, mesenchymal CSC-like CMS4 CRCs.ConclusionsLarge human tumor gene expression datasets representing CRC heterogeneity can provide deep biological insights heretofore not possible with cell line models, suggesting novel repurposed drug combinations. We identified SRC as a common targetable node--an Achilles' heel--in MEKi-targeted therapy-associated resistance in mesenchymal stem-like CRCs, which may help development of a biomarker-driven drug combination (MEKi + SRCi) to treat problematic subpopulations of CRC.

Dataset Information

BI-3406, a Potent and Selective SOS1-KRAS Interaction Inhibitor, Is Effective in KRAS-Driven Cancers through Combined MEK Inhibition.

Publications

BI-3406, a Potent and Selective SOS1-KRAS Interaction Inhibitor, Is Effective in KRAS-Driven Cancers through Combined MEK Inhibition.

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