KRAS

Overview

KRAS is a human gene, formally the KRAS proto-oncogene, GTPase, and also known as Kirsten rat sarcoma viral oncogene homolog. It encodes a small GTPase of the RAS family, a membrane-associated protein that cycles between an inactive GDP-bound state and an active GTP-bound state. This switch is controlled by guanine nucleotide exchange factors such as SOS1, which load GTP onto KRAS, and by GTPase-activating proteins that accelerate GTP hydrolysis. In its active conformation, KRAS transmits signals from upstream receptor tyrosine kinases, including the EGFR family, to downstream effectors, most prominently the RAF–MEK–ERK (MAPK) cascade and the PI3K/AKT pathway, thereby regulating cell proliferation, differentiation, and survival. The protein requires prenylation and membrane localization for activity, and alternative splicing produces the K-Ras4A and K-Ras4B isoforms.

Somatic missense mutations in KRAS, typically at codons 12, 13, and 61, impair GTP hydrolysis and lock the protein in a constitutively active state, driving sustained MAPK and PI3K/AKT signaling. KRAS is among the most frequently mutated oncogenes in human cancer, with the highest prevalence in pancreatic ductal adenocarcinoma and substantial involvement in colorectal cancer, lung adenocarcinoma, and appendiceal adenocarcinoma; co-occurring alterations in TP53, STK11, KEAP1, and PIK3CA further shape tumor behavior and clinical outcomes. Long considered undruggable, KRAS is now addressed by several therapeutic strategies: covalent inhibitors of the KRAS G12C variant, pan-RAS inhibitors, allele-selective agents, SOS1 inhibitors that block nucleotide exchange, and targeted degraders built as proteolysis-targeting chimeras. Because resistance to single-agent KRAS inhibition arises rapidly — through reactivation of parallel signaling nodes, lineage plasticity, and upstream or orthogonal pathways involving EGFR, RAF1, and JAK2/STAT3 — combination regimens pairing KRAS-directed drugs with MEK inhibitors such as trametinib, PI3K inhibitors, or receptor tyrosine kinase inhibitors are an active focus of preclinical and clinical development. Genetically engineered mouse models carrying conditional Kras and TP53 alleles remain a standard system for studying KRAS-driven tumorigenesis and treatment response.

Recent Publications Summary (latest 30 papers)

Recent research has focused on expanding therapeutic options against oncogenic KRAS through diverse inhibitor development strategies. Pan-KRAS inhibitors that target both GDP- and GTP-bound states have emerged as promising candidates, with AM-2383 demonstrating efficacy against KRASG12D and KRASG12V mutations while sparing HRAS and NRAS isoforms 42446418Jul. Allele-specific inhibitors continue to gain traction, with DN022150 designed for KRAS G12D and HRS-4642 showing promise in combination with anti-PD-L1 antibodies or antibody-drug conjugates in clinical evaluation 42571010Aug. Drug repurposing strategies have identified FDA-approved compounds with KRAS-targeting potential, with nilotinib and risperidone showing high affinity for the KRAS G12C switch-II pocket and markedly reducing NSCLC cell viability, colony formation, and angiogenesis in functional assays 42595781Aug. The approval of covalent KRASG12C inhibitors such as sotorasib and adagrasib has catalyzed discovery efforts across diverse KRAS mutations and tumor types, including rare malignancies such as appendiceal adenocarcinoma 42393724Jul.

Targeting upstream regulators of KRAS signaling has emerged as a complementary strategy. SOS1, a guanine nucleotide exchange factor critical for KRAS activation, has proven to be an attractive therapeutic target. Potent and selective SOS1 inhibitors (compounds 78b and 78d) successfully disrupted the SOS1-KRASG12C interaction and inhibited nucleotide exchange across multiple KRAS variants, achieving significant tumor growth inhibition (75.1% to 86.2%) in colorectal cancer xenografts at well-tolerated doses 42247371Jun. Structure-based optimization yielded SL43, which demonstrated superior binding affinity to SOS1, potent antiproliferative activity against KRAS-mutant colorectal cancer cells with over 100-fold selectivity over wild-type KRAS cells, and favorable pharmacokinetic properties including high oral bioavailability 41950716Apr. BI-3406, another SOS1 inhibitor, has been evaluated in combination regimens to address efficacy and safety considerations 42399819Jul.

Multi-target combination strategies have demonstrated substantial antitumor efficacy while addressing adaptive resistance mechanisms. Triple inhibition targeting KRAS (daraxonrasib/RMC-6236), EGFR (afatinib), and STAT3 (SD36) achieved complete regression of orthotopic pancreatic ductal adenocarcinoma tumors in genetically engineered mice and patient-derived xenografts with no tumor relapse over 200 days of treatment and favorable tolerability 42224594Jun. The phase III RASolute-302 trial demonstrated that daraxonrasib nearly doubled median overall survival (13.2 vs. 6.6 months) and progression-free survival in second-line metastatic pancreatic cancer compared to chemotherapy 42571010Aug. EGFR and RAF co-inhibition has been explored in KRAS-driven pancreatic cancer, as EGFR-mediated pathway reactivation can drive adaptive resistance to KRAS inhibition alone 42030284Apr41801133Mar. immunotherapy combinations have shown promise, with studies examining checkpoint inhibitors alongside targeted KRAS therapies and strategies to reprogram the tumor microenvironment, including the use of an iridium(III) complex (Ir-estin) that couples immunogenic cell death in KRAS-mutant tumors with AMPK-dependent tumor-associated macrophage reprogramming 42437351Jul.

Alternative targeting modalities have revealed additional therapeutic vulnerabilities in KRAS-driven Cancers. G-quadruplex stabilizers targeting the KRAS promoter region have demonstrated antitumor activity, with compound 7i showing a dual-binding mode to KRAS-G4 with 20-fold improved antiproliferative activity over the natural product lead dehydroevodiamine 42251661Jun. Bifunctional G4 ligands targeting both c-Myc and KRAS promoters have induced ferroptosis and immunogenic cell death in breast cancer cells with robust in vivo tumor growth inhibition 41719920Feb. Proteolysis-targeting chimeras (PROTACs) designed for KRAS G12V degradation induced rapid tumor regression in lung adenocarcinoma models, though disease relapse was associated with dysregulation of proteolysis machinery 42200804May. Fragment assembly strategies have identified linear indoxadiazole compounds as viable KRAS inhibitors, with compound 10b demonstrating inhibitory activity against KRASG12C and KRASG12D in pancreatic cancer cells and selective downregulation of downstream phosphoproteins 41931988Apr. Advanced computational approaches including deep learning (DENet) and shape-constrained diffusion models (Diff-Shape) have identified complex KRAS variants with enhanced drug resistance and synthesizable inhibitor candidates with nanomolar potency 42190010May41973903Apr.

Clinical and translational research has established KRAS as a critical biomarker for patient stratification and therapeutic selection across multiple cancer types. The most common KRAS mutation in pancreatic cancer, G12D, occurs in approximately 90% of tumors, and human pancreatic progenitor organoid models have revealed that CDKN2A loss, nearly universal in patients but dispensable in mouse models, is essential for neoplastic transformation when combined with KRAS and TP53 mutations 42161274May. Mutation detection in cell-free DNA has been advanced through CRISPR-Cas12a-based assays (RECO-Cas), achieving 0.01% variant allele frequency sensitivity with high sensitivity (90.48%) and specificity (100%) for KRAS, EGFR, and PIK3CA point mutations 42172311May. Co-occurrence of TP53 and KRAS mutations has been associated with poor overall survival in biliary tract cancer following immunochemotherapy 42190397May, while STK11 co-mutations with KEAP1 and KRAS in metastatic non-small cell lung cancer have shown distinct clinical outcomes 42377736Jun. Emerging findings indicate that cellular plasticity mediated by transcription factors such as HNF4α can promote resistance to KRAS inhibition through increased NRF2 activity in invasive mucinous lung adenocarcinoma 42383354Jul, and aging epigenetically reprograms KRAS-driven lung adenocarcinoma through activation of integrated stress response pathways to enhance metastatic spread 42013364Apr.

What Changes, What Holds

1. Pan-KRAS inhibitors and repurposed small molecules expand coverage across multiple mutation variants -- REINFORCES -- AM-2383, DN022150, and repurposed compounds like nilotinib extend the covalent and allele-selective inhibitor strategies the Overview identifies as established. Discovery of KRAS-targeting activity in FDA-approved drugs and application to rare malignancies like appendiceal adenocarcinoma validate the therapeutic paradigm already in place without overturning its foundational approaches 42446418Jul42595781Aug.

2. SOS1 inhibitors achieve 100-fold selectivity for KRAS-mutant over wild-type cells -- REINFORCES -- Compounds 78b, 78d, and SL43 disrupt nucleotide exchange with potent selectivity, confirming SOS1 as the viable target the Overview names. Mechanistic validation across multiple KRAS variants and favorable pharmacokinetics sharpen understanding of allele-specific effects without departing from the established SOS1-inhibitor strategy 42247371Jun41950716Apr.

3. Multi-targeted combination therapy achieves doubled survival in advanced pancreatic cancer -- REINFORCES -- Daraxonrasib combined with EGFR inhibition nearly doubled median overall survival in the phase III RASolute-302 trial, elevating combination therapy from "active focus" to demonstrated clinical benefit. Preclinical triple KRAS-EGFR-STAT3 inhibition achieves complete regression; immunotherapy partnerships with macrophage reprogramming signal emerging directions beyond the kinase-focused regimens the baseline discusses 42571010Aug42437351Jul.

4. G-quadruplex stabilization and ferroptosis provide mechanistic alternatives to GTPase inhibition -- NEW DIRECTION -- Compound 7i triggers ferroptosis via KRAS-G4 stabilization through transcriptional mechanisms distinct from direct GTPase inhibition. Bifunctional G4 ligands targeting c-Myc and KRAS simultaneously demonstrate robust in vivo tumor suppression. Fragment-assembly and deep-learning discovery approaches offer methodologies for identifying such alternative mechanisms the Overview does not address 42251661Jun41719920Feb.

5. CDKN2A is essential for human KRAS transformation but dispensable in mouse models -- NEW DIRECTION -- Human pancreatic organoids reveal CDKN2A is critical when combined with KRAS and TP53 mutations, despite being nearly universal in patients yet unnecessary in standard mouse models 42161274May. Separately, cellular plasticity via HNF4α and aging-driven integrated stress response reprogramming represent mechanistic routes to resistance outside the direct-inhibition paradigm 42383354Jul42013364Apr. These findings identify species differences that qualify model applicability and reveal novel resistance mechanisms.

Overview update candidates: RASolute-302 clinical trial demonstrating that multi-targeted combination therapy (daraxonrasib + EGFR inhibitor) nearly doubles median overall survival in second-line metastatic pancreatic cancer.