KRAS-mutant Lung Cancer Research Articles

Divergent clinical and immunologic outcomes based on STK11 co-mutation status in resectable KRAS-mutant lung cancers following neoadjuvant immune checkpoint blockade.

Co-mutations of the KRAS and STK11 genes in advanced non-small cell lung cancer (NSCLC) are associated with immune checkpoint blockade (ICB) resistance. While neoadjuvant chemoimmunotherapy is now a standard of care treatment for resectable NSCLC, the clinical and immunologic impact of KRAS andSTK11 co-mutations in this setting are unknown. We evaluated and compared recurrence-free survival of resectable KRAS-mutated NSCLC tumors, with or without co-occuring STK11 mutations, treated with neoadjuvant ICB. Single cell transcriptomics was performed on tumor-infiltrating T cells from 7 KRASmut/STK11wttumors and 6 KRASmut/STK11mut tumors. Relative to KRASmut/STK11wttumors, KRASmut/STK11mut exhibited significantly higher recurrence risk. Single-cell transcriptomics showed enhanced oxidative phosphorylation with evidence of decreased PGE-2 signaling and increased IL-2 signaling in CD8+ tumor-infiltrating lymphocytes (TIL) from KRASmut/STK11mut tumors, a finding that was mirrored in KRASwt tumors that relapsed. TIL from KRASmut/STK11mut tumors expressed high levels of molecules associated with tumor residence, including CD39 and ZNF683 (HOBIT). These divergent T cell transcriptional fates suggest T cell maintenance and residence may be detrimental to anti-tumor immunity in the context of neoadjuvant ICB for resectable NSCLC, regardless of KRAS mutation status. Our work provides a basis for future investigations into the mechanisms underpinning PGE-2 and IL-2 signaling as they relate to T cell immunity to cancer and to divergent clinical outcomes in KRASmut/STK11mut NSCLC treated with neoadjuvant ICB.

Protein-RNA interaction dynamics reveal key regulators of oncogenic KRAS-driven cancers

KRAS is one of the most frequently mutated oncogenes across various cancers. Oncogenic KRAS mutations rewire cellular signaling, leading to significant alterations in gene expression. RNA-binding proteins (RBPs) play a pivotal role in gene expression regulation by post-transcriptionally controlling various aspects of RNA metabolism. It has become clear that interactions between RBPs and RNA are frequently dysregulated in numerous cancers. However, how oncogenic KRAS mutations reshape the post-transcriptional regulatory network mediated by RBPs remains poorly understood. In this study, we systematically dissected oncogenic KRAS-driven alterations of RNA-RBP networks. We identified 35 cancer-associated RBPs with either increased or decreased RNA binding upon oncogenic KRAS activation, including PDCD11, which is essential for the viability of KRAS mutant cancers, and ELAVL2, which regulates cell migration in KRAS mutant lung cancers. Our study serves as a crucial resource for elucidating RBP regulatory networks in KRAS mutant cancers and may provide new avenues for therapeutic strategies targeting KRAS mutant malignancies.

Treatment of a mutant KRAS lung cancer cell line with polyisoprenylated cysteinyl amide inhibitors activates the MAPK pathway, inhibits cell migration and induces apoptosis.

KRAS mutations are the most common oncogenic mutations in lung adenocarcinoma in Black Americans. Polyisoprenylated Cysteinyl amide Inhibitors (PCAIs) constitute a group of potential cancer therapy agents that we designed to specifically disrupt and suppress hyperactive G-protein signaling, such as that caused by mutated RAS proteins. Here we determine the effects of PCAIs on the viability, G-protein levels, downstream mediators, and apoptosis-related proteins on the KRAS-mutated, Black American-derived lung adenocarcinoma cell line, NCI-H23. Of the 17 PCAIs tested, compounds NSL-YHJ-2-27 and NSL-YHJ-2-46 showed the most potency with EC50 values of 2.7 and 3.3 μM, respectively. Western blotting was used to determine the effect of the PCAIs on the phosphorylation levels of MAPK pathway enzymes. After 48 h exposure to 5 μM of the PCAIs, NSL-YHJ-2-46, the MAPK proteins BRAF, MEK1/2, ERK1/2, and p90RSK were activated through phosphorylation by 90, 190, 150 and 120%, respectively. However, CRAF/RAF1 phosphorylation decreased by 40%, suggesting significant changes in the KRAS/MAPK signaling patterns. Furthermore, 5 μM of NSL-YHJ-2-27 depleted the singly polyisoprenylated monomeric G-proteins RAC 1/2/3 and CDC42 by 77 and 76%, respectively. The depletion of these key cytoskeletal proteins may account for the observed inhibition of cell migration and invasion, and spheroid invasion observed on exposure to NSL-YHJ-2-27 and NSL-YHJ-2-46. Treatment with 5 μM of NSL-YHJ-2-27 suppressed full-length inactive caspase 3 and 7 levels by 72 and 91%, respectively. An analysis of cells treated with the fluorescently labeled active caspase 3/7 irreversible inhibitor, CaspaTagTM Caspase-3/7 in situ reagent revealed a 124% increase in active caspase at 3 μM over controls. These findings clearly show the direct effects of the PCAIs on the RAS signaling pathway. Given the profound increases observed in RPS6KA1/p90RSK phosphorylation, future work will involve a determination whether the proapoptotic isoforms of RPS6KA1/p90RSK are phosphorylated due to the PCAIs treatments. These results support the potential use of the PCAIs as targeted therapies against cancers with KRAS mutations.

P1.06B.07 Association of NEDD9 Expression and Survival of Patients with KRAS Mutant and STK11 Mutant Non-Small Cell Lung Cancer (KRASMUT/STK11MUT-NSCLC)

P1.06B.07 Association of NEDD9 Expression and Survival of Patients with KRAS Mutant and STK11 Mutant Non-Small Cell Lung Cancer (KRASMUT/STK11MUT-NSCLC)

Transcriptional repression by HDAC3 mediates T cell exclusion from Kras mutant lung tumors

Histone Deacetylase 3 (HDAC3) function in vivo is nuanced and directed in a tissue-specific fashion. The importance of HDAC3 in Kras mutant lung tumors has recently been identified, but HDAC3 function in this context remains to be fully elucidated. Here, we identified HDAC3 as a lung tumor cell-intrinsic transcriptional regulator of the tumor immune microenvironment. In Kras mutant lung cancer cells, we found that HDAC3 is a direct transcriptional repressor of a cassette of secreted chemokines, including Cxcl10. Genetic and pharmacological inhibition of HDAC3 robustly up-regulated this gene set in human and mouse Kras, LKB1 (KL) and Kras, p53 (KP) mutant lung cancer cells through an NF-κB/p65-dependent mechanism. Using genetically engineered mouse models, we found that HDAC3 inactivation in vivo induced expression of this gene set selectively in lung tumors and resulted in enhanced T cell recruitment at least in part via Cxcl10. Furthermore, we found that inhibition of HDAC3 in the presence of Kras pathway inhibitors dissociated Cxcl10 expression from that of immunosuppressive chemokines and that combination treatment of entinostat with trametinib enhanced T cell recruitment into lung tumors in vivo. Finally, we showed that T cells contribute to in vivo tumor growth control in the presence of entinostat and trametinib combination treatment. Together, our findings reveal that HDAC3 is a druggable endogenous repressor of T cell recruitment into Kras mutant lung tumors.

EP.12C.04 Location of Metastases and Prognosis of Patients with Metastatic KRAS-Mutant Non-Small Cell Lung Cancer

EP.12C.04 Location of Metastases and Prognosis of Patients with Metastatic KRAS-Mutant Non-Small Cell Lung Cancer

Yap methylation-induced FGL1 expression suppresses anti-tumor immunity and promotes tumor progression in KRAS-driven lung adenocarcinoma.

Despite significant strides in lung cancer immunotherapy, the response rates for Kirsten rat sarcoma viral oncogene homolog (KRAS)-driven lung adenocarcinoma (LUAD) patients remain limited. Fibrinogen-like protein 1 (FGL1) is a newly identified immune checkpoint target, and the study of related resistance mechanisms is crucial for improving the treatment outcomes of LUAD patients. This study aimed to elucidate the potential mechanism by which FGL1 regulates the tumor microenvironment in KRAS-mutated cancer. The expression levels of FGL1 and SET1 histone methyltransferase (SET1A) in lung cancer were assessed using public databases and clinical samples. Lentiviruses were constructed for transduction to overexpress or silence FGL1 in lung cancer cells and mouse models. The effects of FGL1 and Yes-associated protein (Yap) on the immunoreactivity of cytotoxic T cells in tumor tissues were evaluated using immunofluorescence staining and flow cytometry. Chromatin immunoprecipitation and dual luciferase reporter assays were used to study the SET1A-directed transcriptional program. Upregulation of FGL1 expression in KRAS-mutated cancer was inversely correlated with the infiltration of CD8+ T cells. Mechanistically, KRAS activated extracellular signal-regulated kinase 1/2 (ERK1/2), which subsequently phosphorylated SET1A and increased its stability and nuclear localization. SET1A-mediated methylation of Yap led to Yap sequestration in the nucleus, thereby promoting Yap-induced transcription of FGL1 and immune evasion in KRAS-driven LUAD. Notably, dual blockade of programmed cell death-1 (PD-1) and FGL1 further increased the therapeutic efficacy of anti-PD-1 immunotherapy in LUAD patients. FGL1 could be used as a diagnostic biomarker of KRAS-mutated lung cancer, and targeting the Yap-FGL1 axis could increase the efficacy of anti-PD-1 immunotherapy.

Combining RAS(ON) G12C-selective inhibitor with SHP2 inhibition sensitises lung tumours to immune checkpoint blockade

Mutant selective drugs targeting the inactive, GDP-bound form of KRASG12C have been approved for use in lung cancer, but resistance develops rapidly. Here we use an inhibitor, (RMC-4998) that targets RASG12C in its active, GTP-bound form, to treat KRAS mutant lung cancer in various immune competent mouse models. RAS pathway reactivation after RMC-4998 treatment could be delayed using combined treatment with a SHP2 inhibitor, which not only impacts tumour cell RAS signalling but also remodels the tumour microenvironment to be less immunosuppressive. In an immune inflamed model, RAS and SHP2 inhibitors in combination drive durable responses by suppressing tumour relapse and inducing development of immune memory. In an immune excluded model, combined RAS and SHP2 inhibition sensitises tumours to immune checkpoint blockade, leading to efficient tumour immune rejection. These preclinical results demonstrate the potential of the combination of RAS(ON) G12C-selective inhibitors with SHP2 inhibitors to sensitize tumours to immune checkpoint blockade.

The HOXC10/NOD1/ERK axis drives osteolytic bone metastasis of pan-KRAS-mutant lung cancer

While KRAS mutation is the leading cause of low survival rates in lung cancer bone metastasis patients, effective treatments are still lacking. Here, we identified homeobox C10 (HOXC10) as a lynchpin in pan-KRAS-mutant lung cancer bone metastasis. Through RNA-seq approach and patient tissue studies, we demonstrated that HOXC10 expression was dramatically increased. Genetic depletion of HOXC10 preferentially impeded cell proliferation and migration in vitro. The bioluminescence imaging and micro-CT results demonstrated that inhibition of HOXC10 significantly reduced bone metastasis of KRAS-mutant lung cancer in vivo. Mechanistically, the transcription factor HOXC10 activated NOD1/ERK signaling pathway to reprogram epithelial-mesenchymal transition (EMT) and bone microenvironment by activating the NOD1 promoter. Strikingly, inhibition of HOXC10 in combination with STAT3 inhibitor was effective against KRAS-mutant lung cancer bone metastasis by triggering ferroptosis. Taken together, these findings reveal that HOXC10 effectively alleviates pan-KRAS-mutant lung cancer with bone metastasis in the NOD1/ERK axis-dependent manner, and support further development of an effective combinatorial strategy for this kind of disease.

Poor therapeutic outcomes in KRAS-mutant non-small cell lung cancer due to chemoresistance conferred by SLC7A11.

This study aimed to confirm whether Kirsten rat sarcoma viral oncogene (KRAS) mutations affect the therapeutic efficacy of non-small cell lung cancer (NSCLC) and, if so, to explore what the possible mechanisms might be. We retrospectively analyzed the efficacy of immunochemotherapy in KRAS-mutant NSCLC patients compared to driver-negative patients. Online data platforms were used to find immunotherapy cases, and survival analysis compared treatments' efficacy. Cytotoxicity assays measured chemosensitivity in KRAS-mutant versus wild-type NSCLC to drugs like paclitaxel, carboplatin, and pemetrexed. Bioinformatics confirmed the KRAS-SLC7A11 link and cell experiments tested SLC7A11's role in chemoresistance. Animal studies verified the antitumor effects of SLC7A11 inhibitors with chemotherapy. Patients with KRAS-mutated NSCLC have a shorter therapeutic effectiveness duration with immunochemotherapy than patients with driver gene-negative status. The efficacy of immunotherapy alone is similar between the two groups. The KRAS mutation can enhance chemoresistance by upregulating SLC7A11, and inhibiting SLC7A11 can increase the sensitivity of KRAS-mutated NSCLC to chemotherapy. This study suggests that KRAS-mutant NSCLC can enhance its acquired chemoresistance by overexpressing SLC7A11, leading to poorer therapeutic outcomes. Targeting the KRAS-SLC7A11 axis could increase sensitivity to chemotherapeutic drugs, providing theoretical support for future treatment directions.

Mechanisms of Response and Tolerance to Active RAS Inhibition in KRAS-Mutant Non-Small Cell Lung Cancer.

Resistance to inactive state-selective RASG12C inhibitors frequently entails accumulation of RASGTP, rendering effective inhibition of active RAS potentially desirable. Here, we evaluated the antitumor activity of the RAS(ON) multiselective tricomplex inhibitor RMC-7977 and dissected mechanisms of response and tolerance in KRASG12C-mutant non-small cell lung cancer (NSCLC). Broad-spectrum reversible RASGTP inhibition with or without concurrent covalent targeting of active RASG12C yielded superior and differentiated antitumor activity across diverse comutational KRASG12C-mutant NSCLC mouse models of primary or acquired RASG12C(ON) or RASG12C(OFF) inhibitor resistance. Interrogation of time-resolved single-cell transcriptional responses established an in vivo atlas of multimodal acute and chronic RAS pathway inhibition in the NSCLC ecosystem and uncovered a regenerative mucinous transcriptional program that supports long-term tumor cell persistence. In patients with advanced KRASG12C-mutant NSCLC, the presence of mucinous histologic features portended poor response to sotorasib or adagrasib. Our results have potential implications for personalized medicine and the development of rational RAS inhibitor-anchored therapeutic strategies. Significance: Our work reveals robust and durable antitumor activity of the preclinical RAS(ON) multiselective inhibitor RMC-7977 against difficult-to-treat subsets of KRASG12C-mutant NSCLC with primary or acquired RASG12C inhibitor resistance and identifies a conserved mucinous transcriptional state that supports RAS inhibitor tolerance. See related commentary by Marasco and Misale, p. 2018.

Concurrent loss of LKB1 and KEAP1 enhances SHMT-mediated antioxidant defence in KRAS-mutant lung cancer.

Non-small-cell lung cancer (NSCLC) with concurrent mutations in KRAS and the tumour suppressor LKB1 (KL NSCLC) is refractory to most therapies and has one of the worst predicted outcomes. Here we describe a KL-induced metabolic vulnerability associated with serine-glycine-one-carbon (SGOC) metabolism. Using RNA-seq and metabolomics data from human NSCLC, we uncovered that LKB1 loss enhanced SGOC metabolism via serine hydroxymethyltransferase (SHMT). LKB1 loss, in collaboration with KEAP1 loss, activated SHMT through inactivation of the salt-induced kinase (SIK)-NRF2 axis and satisfied the increased demand for one-carbon units necessary for antioxidant defence. Chemical and genetic SHMT suppression increased cellular sensitivity to oxidative stress and cell death. Further, the SHMT inhibitor enhanced the in vivo therapeutic efficacy of paclitaxel (first-line NSCLC therapy inducing oxidative stress) in KEAP1-mutant KL tumours. The data reveal how this highly aggressive molecular subtype of NSCLC fulfills their metabolic requirements and provides insight into therapeutic strategies.

Spatial iTME analysis of KRAS mutant NSCLC and immunotherapy outcome

We conducted spatial immune tumor microenvironment (iTME) profiling using formalin-fixed paraffin-embedded (FFPE) samples of 25 KRAS-mutated non-small cell lung cancer (NSCLC) patients treated with immune checkpoint inhibitors (ICIs), including 12 responders and 13 non-responders. An eleven-marker panel (CD3, CD4, CD8, FOXP3, CD68, arginase-1, CD33, HLA-DR, pan-keratin (PanCK), PD-1, and PD-L1) was used to study the tumor and immune cell compositions. Spatial features at single cell level with cellular neighborhoods and fractal analysis were determined. Spatial features and different subgroups of CD68+ cells and FOXP3+ cells being associated with response or resistance to ICIs were also identified. In particular, CD68+ cells, CD33+ and FOXP3+ cells were found to be associated with resistance. Interestingly, there was also significant association between non-nuclear expression of FOXP3 being resistant to ICIs. We identified CD68dim cells in the lung cancer tissues being associated with improved responses, which should be insightful for future studies of tumor immunity.

KRAS-mutant non-small cell lung cancer (NSCLC) therapy based on tepotinib and omeprazole combination

BackgroundKRAS-mutant non-small cell lung cancer (NSCLC) shows a relatively low response rate to chemotherapy, immunotherapy and KRAS-G12C selective inhibitors, leading to short median progression-free survival, and overall survival. The MET receptor tyrosine kinase (c-MET), the cognate receptor of hepatocyte growth factor (HGF), was reported to be overexpressed in KRAS-mutant lung cancer cells leading to tumor-growth in anchorage-independent conditions.MethodsCell viability assay and synergy analysis were carried out in native, sotorasib and trametinib-resistant KRAS-mutant NSCLC cell lines. Colony formation assays and Western blot analysis were also performed. RNA isolation from tumors of KRAS-mutant NSCLC patients was performed and KRAS and MET mRNA expression was determined by real-time RT-qPCR. In vivo studies were conducted in NSCLC (NCI-H358) cell-derived tumor xenograft model.ResultsOur research has shown promising activity of omeprazole, a V-ATPase-driven proton pump inhibitor with potential anti-cancer properties, in combination with the MET inhibitor tepotinib in KRAS-mutant G12C and non-G12C NSCLC cell lines, as well as in G12C inhibitor (AMG510, sotorasib) and MEK inhibitor (trametinib)-resistant cell lines. Moreover, in a xenograft mouse model, combination of omeprazole plus tepotinib caused tumor growth regression. We observed that the combination of these two drugs downregulates phosphorylation of the glycolytic enzyme enolase 1 (ENO1) and the low-density lipoprotein receptor-related protein (LRP) 5/6 in the H358 KRAS G12C cell line, but not in the H358 sotorasib resistant, indicating that the effect of the combination could be independent of ENO1. In addition, we examined the probability of recurrence-free survival and overall survival in 40 early lung adenocarcinoma patients with KRAS G12C mutation stratified by KRAS and MET mRNA levels. Significant differences were observed in recurrence-free survival according to high levels of KRAS mRNA expression. Hazard ratio (HR) of recurrence-free survival was 7.291 (p = 0.014) for high levels of KRAS mRNA expression and 3.742 (p = 0.052) for high MET mRNA expression.ConclusionsWe posit that the combination of the V-ATPase inhibitor omeprazole plus tepotinib warrants further assessment in KRAS-mutant G12C and non G12C cell lines, including those resistant to the covalent KRAS G12C inhibitors.

Brain metastases in clinical trial participants with KRAS-mutated advanced non-small cell lung cancer receiving docetaxel: Pooled data analysis

ObjectivesLimited data are available on central nervous system (CNS) efficacy with standard-of-care therapies for KRAS-mutated (KRASmut) advanced non-small cell lung cancer (NSCLC). The objective of this study was to investigate the incidence and progression of brain metastases in KRASmut advanced NSCLC treated with docetaxel using pooled data from historical clinical trials. Materials and MethodsData from phase 2/3 trials of docetaxel-containing regimens in advanced NSCLC were sourced from the Medidata platform. Analysis was restricted to stage IIIB-IV KRASmut NSCLC with disease progression after ≥ 1 systemic anticancer therapy. Participants with asymptomatic, treated, and stable brain metastases were included. Endpoints included 12-month CNS disease control rate (CNS-DCR) and CNS progression per Response Evaluation Criteria in Solid Tumors; progression-free survival (PFS); and overall survival (OS). Data were pooled and analyses stratified by baseline brain metastases status. ResultsA total of 595 participants were included in the analysis (62 [10%] with baseline brain metastases and 533 [90 %] without). Among participants with brain metastases, 17 (27.4 %) had CNS progression during docetaxel treatment and 12-month CNS-DCR was 75.8 %; 45 (8.4 %) participants without baseline brain metastases developed brain metastases during treatment. In an analysis restricted to patients with metastatic disease, outcomes with and without baseline brain metastases included: median PFS, 3.3 and 4.9 months (p < 0.005); 12-month PFS, 5 % and 16 %; median OS, 6.9 and 10.4 months (p < 0.005); and 12-month OS, 20 % and 44 %, respectively. ConclusionThese findings establish CNS progression rates with docetaxel in previously treated KRASmut advanced NSCLC and facilitate interpretation of data from ongoing randomized clinical trials of novel KRAS-targeted therapeutic strategies vs. docetaxel.

Molecular and clinical characteristics of patients with non-small-cell lung cancer (NSCLC) harboring KRAS G12V mutations.

8618 Background: KRAS G12V is one of the most common drivers of non-small cell lung cancer (NSCLC), accounting for around 3 percent of cases. Recently, there have been promising approaches in early clinical research to therapeutically target this mutation. However, this subset of patients is poorly characterized both molecularly and clinically, and data on therapy-dependent outcome are lacking. We performed this real world analysis to gain insight into the genomic and clinical characteristics of a large cohort of NSCLC patients with KRAS G12V mutations. Methods: Molecular data of 662 UICC stage I-IV lung cancer patients diagnosed between 2018 and 2023 and harbouring a KRAS G12V mutation in their tumor tissue were linked to the medical record data in the Network Genomic Medicine (NGM) database. The mutational status was determined by next-generation sequencing (NGS) and further immunohistochemistry (IHC) for PD-L1 status was performed. Results: 662 patients with a KRAS G12V mutation were diagnosed between 01/2018 and 03/2023 (stage I: 33 (6.0%), II: 29 (5.3%), III: 89 (16.3%), IV: 396 (72.4%)), which is a proportion of 15.3% among all registered KRAS-mutated lung cancer patients in this period (n=4332). Among the KRASG12V positive primary lung carcinomas, 605 (94.3%) showed an adenocarcinoma and 17 (2.6%) a squamous cell carcinoma. The median age at diagnosis was 67 years (range: 33-91), of which 338 were men (52.6%) and 304 women (47.4%). The majority of the cohort were active or former smokers (active: 289 (54.9%); former: 208 (39.2%)). In the group of never smokers (n=33, 6.2%), there were 5 men (15.2% of never smokers) and 28 women (84.8% of never smokers). The most common mutation site at initial diagnosis in patients with metastatic disease was brain and bone metastases with 41.5% and 37.4%, respectively. The most common co-mutations with a frequency of ≥ 5% were TP53 (40.2%), STK11 (28.3%), KEAP1 (22.6%) and NTRK1-3 (8.7%). Preliminary median overall survival at UICC stage IV was 525 (95% CI: 427 – 579) days. The first PD-L1-independent analysis showed a response rate of 40.9% (18/44) to initial chemotherapy (CTX)/immune-checkpoint blockade (ICB) combination, 66.7% (8/13) to ICB alone and 18.8% (6/32) to CTX alone. Conclusions: The cohort is characterized by heavy tobacco consumption. Among the never-smokers, the high proportion of women is noteworthy and will be analyzed further. Metastases at first diagnosis and concurrent mutations show clear differences to other KRAS subtypes, which highlights the heterogeneity of KRAS subtypes. We will continue to analyze the overall prognosis as well as the first indications of a PD-L1-independent benefit of immunotherapy compared to chemotherapy alone.

Gene expression correlates of adagrasib response in KRASG12C mutated non-small cell lung cancer (NSCLC).

8529 Background: KRASG12C inhibitors such as adagrasib and sotorasib have shown clinical promise in targeting KRASG12C-mutated lung cancers; however, most patients develop primary or secondary resistance. A biomarker of response to KRASG12C inhibitor is needed for better patient stratification and to understand the resistance mechanism. Methods: We analyzed transcriptional correlates of adagrasib treatment outcome in 68 patients in the KRYSTAL-1 trial, a phase 1/2 clinical trial of adagrasib monotherapy in the second line and beyond treatment for NSCLC. We also treated KRAS-mutated lung cancer mouse models and organoids with a KRAS inhibitor for the long term and characterized the resistant tumors’ transcriptional profile to identify resistance mechanisms. We also performed serial gene expression analysis of KrasG12D mutated lung organoids undergoing squamous transformation to identify transcription factor involved in the resistance process. Results: In patients with lung adenocarcinoma with KRASG12C and STK11/ LKB1 co-mutations, we find an enrichment of the squamous cell carcinoma gene signature in pre-treatment biopsies correlates with a poor response to adagrasib. Studies of Lkb1-deficient KRASG12C and KrasG12D lung cancer mouse models and organoids, treated with KRAS inhibitors adagrasib and MRTX1133, respectively, reveal that tumors invoke a lineage plasticity program, adeno-to-squamous transition (AST), that enables resistance to KRAS inhibition. We identify TP63 to be a transcription factor whose expression correlated with squamous transformation. The analysis of lineage plasticity program, adagrasib resistant tumors, and p63 regulon revealed KRT6A to be a common biomarker whose expression correlated with overall survival in the KRYSTAL-1 cohort. Conclusions: KRASG12C mutated lung adenocarcinoma patients with a higher expression of squamous cell carcinoma gene expression signature respond poorly to adagrasib treatment. Expression of the AST plasticity signature and KRT6A at baseline correlates with poor adagrasib responses. These data indicate the role of AST in KRAS inhibitor resistance and provide predictive biomarkers for KRAS-targeted therapies in lung cancer.

Epithelial-mesenchymal transition status is a remarkable biomarker for the combination treatment with avutometinib and defactinib in KRAS-mutated non-small cell lung cancer.

Recent therapeutic strategies for KRAS-mutated cancers that inhibit the MAPK pathway have attracted considerable attention. The RAF/MEK clamp avutometinib (VS-6766/CH5126766/RO5126766/CKI27) is promising for patients with KRAS-mutated cancers. Although avutometinib monotherapy has shown clinical activity in patients with KRAS-mutated cancers, effective combination strategies will be important to develop. Using a phosphorylation kinase array kit, we explored the feedback mechanism of avutometinib in KRAS-mutated NSCLC cells, and investigated the efficacy of combining avutometinib with inhibitors of the feedback signal using in vitro and in vivo experiments. Moreover, we searched for a biomarker for the efficacy of combination therapy through an in vitro study and analysis using the The Cancer Genome Atlas Programme dataset. Focal adhesion kinase (FAK) phosphorylation/activation was increased after avutometinib treatment and synergy between avutometinib and FAK inhibitor, defactinib, was observed in KRAS-mutated NSCLC cells with an epithelial rather than mesenchymal phenotype. Combination therapy with avutometinib and defactinib induced apoptosis with upregulation of Bim in cancer cells with an epithelial phenotype in an in vitro and in vivo study. These results demonstrate that the epithelial-mesenchymal transition status may be a promising biomarker for the efficacy of combination therapy with avutometinib and defactinib in KRAS-mutated NSCLC.

Mediator kinase inhibition impedes transcriptional plasticity and prevents resistance to ERK/MAPK-targeted therapy in KRAS-mutant cancers

Acquired resistance remains a major challenge for therapies targeting oncogene activated pathways. KRAS is the most frequently mutated oncogene in human cancers, yet strategies targeting its downstream signaling kinases have failed to produce durable treatment responses. Here, we developed multiple models of acquired resistance to dual-mechanism ERK/MAPK inhibitors across KRAS-mutant pancreatic, colorectal, and lung cancers, and then probed the long-term events enabling survival against this class of drugs. These studies revealed that resistance emerges secondary to large-scale transcriptional adaptations that are diverse and cell line-specific. Transcriptional reprogramming extends beyond the well-established early response, and instead represents a dynamic, evolved process that is refined to attain a stably resistant phenotype. Mechanistic and translational studies reveal that resistance to dual-mechanism ERK/MAPK inhibition is broadly susceptible to manipulation of the epigenetic machinery, and that Mediator kinase, in particular, can be co-targeted at a bottleneck point to prevent diverse, cell line-specific resistance programs.

Targeting WEE1 enhances the antitumor effect of KRAS-mutated non-small cell lung cancer harboring TP53 mutations

The clinical development of Kirsten rat sarcoma virus (KRAS)-G12C inhibitors for the treatment of KRAS-mutant lung cancer is limited by the presence of co-mutations, intrinsic resistance, and the emergence of acquired resistance. Therefore, innovative strategies for enhancing apoptosis in KRAS-mutated non-small cell lung cancer (NSCLC) are urgently needed. Through CRISPR-Cas9 knockout screening using a library of 746 crRNAs and drug screening with a custom library of 432 compounds, we discover that WEE1 kinase inhibitors are potent enhancers of apoptosis, particularly in KRAS-mutant NSCLC cells harboring TP53 mutations. Mechanistically, WEE1 inhibition promotes G2/M transition and reduces checkpoint kinase 2 (CHK2) and Rad51 expression in the DNA damage response (DDR) pathway, which is associated with apoptosis and the repair of DNA double-strand breaks, leading to mitotic catastrophe. Notably, the combined inhibition of KRAS-G12C and WEE1 consistently suppresses tumor growth. Our results suggest targeting WEE1 as a promising therapeutic strategy for KRAS-mutated NSCLC with TP53 mutations.