Project description:Lung cancer is the leading cause of cancer deaths. Tumor heterogeneity, which hampers development of targeted therapies, was herein deconvoluted via single cell RNA sequencing in aggressive human adenocarcinomas (carrying Kras-mutations) and comparable murine model. We identified a tumor-specific, mutant-KRAS-associated subpopulation which is conserved in both human and murine lung cancer. We previously reported a key role for the oncogene BMI-1 in adenocarcinomas. We therefore investigated the effects of in vivo PTC596 treatment, which affects BMI-1 activity, in our murine model. Post-treatment, MRI analysis showed decreased tumor size, while single cell transcriptomics concomitantly detected near complete ablation of the mutant-KRAS-associated subpopulation, signifying the presence of a pharmacologically targetable, tumor-associated subpopulation. Our findings therefore hold promise for the development of a targeted therapy for KRAS-mutant adenocarcinomas.
Project description:Oncogenic STAT3 functions are known in various malignancies. We found that STAT3 plays an unexpected tumor suppressive role in KRAS-mutant non-small-cell-lung cancer (NSCLC). In mice, tissue-specific inactivation of Stat3 resulted in increased Kras (G12D)-driven NSCLC initiation and malignant progression leading to markedly reduced survival. Clinically, low STAT3 expression levels correlate with poor survival in human lung adenocarcinoma patients with smoking history. Consistently, KRAS-mutant lung tumors showed reduced STAT3 levels. Mechanistically, we show that STAT3 controls NFκB-induced IL-8-expression by sequestering NFκB in the cytoplasm while IL-8 in turn regulates myeloid tumor infiltration and tumor vascularization thereby promoting tumor progression. These results identify a novel STAT3-NFκB-IL-8 axis in KRAS-mutant NSCLC with therapeutic and prognostic relevance WT: Control lung; KRAS: Lung tumors expressing KRAS G12D; KRAS STAT3 KO: Lung tumors expressing KRAS G12D- STAT3 deficient; tumors of four mice pooled per sample
Project description:Oncogenic STAT3 functions are known in various malignancies. We found that STAT3 plays an unexpected tumor suppressive role in KRAS-mutant non-small-cell-lung cancer (NSCLC). In mice, tissue-specific inactivation of Stat3 resulted in increased Kras (G12D)-driven NSCLC initiation and malignant progression leading to markedly reduced survival. Clinically, low STAT3 expression levels correlate with poor survival in human lung adenocarcinoma patients with smoking history. Consistently, KRAS-mutant lung tumors showed reduced STAT3 levels. Mechanistically, we show that STAT3 controls NFκB-induced IL-8-expression by sequestering NFκB in the cytoplasm while IL-8 in turn regulates myeloid tumor infiltration and tumor vascularization thereby promoting tumor progression. These results identify a novel STAT3-NFκB-IL-8 axis in KRAS-mutant NSCLC with therapeutic and prognostic relevance
Project description:Oncogenic KRAS is found in more than 25% of lung adenocarcinomas, the major histologic subtype of non–small cell lung cancer (NSCLC), and is an important target for drug development. To this end, we generated four NSCLC lines with stable knockdown selective for oncogenic KRAS. As expected, stable knockdown of oncogenic KRAS led to inhibition of in vitro and in vivo tumor growth in the KRAS-mutant NSCLC cells, but not in NSCLC cells that have wild-type KRAS (but mutant NRAS). Surprisingly, we did not see large-scale induction of cell death and the growth inhibitory effect was not complete. To further understand the ability of NSCLCs to grow despite selective removal of mutant KRAS expression, we conducted microarray expression profiling of NSCLC cell lines with or without mutant KRAS knockdown and isogenic human bronchial epithelial cell lines with and without oncogenic KRAS. We found that although the mitogen-activated protein kinase pathway is significantly downregulated after mutant KRAS knockdown, these NSCLCs showed increased levels of phospho-STAT3 and phospho–epidermal growth factor receptor, and variable changes in phospho-Akt. In addition, mutant KRAS knockdown sensitized the NSCLCs to p38 and EGFR inhibitors. Our findings suggest that targeting oncogenic KRAS by itself will not be sufficient treatment, but may offer possibilities of combining anti-KRAS strategies with other targeted drugs. Detailed information on the microarray results are available in a previous study (Sunaga N, et al. Mol Cancer Ther. 2011;10:336-46).
Project description:KRAS-mutant non-small cell lung cancer (NSCLC) is one of the main subtypes across lung cancers. Despite the enormous studies on KRAS-mutant NSCLC, new therapeutic targets need to be identified because current therapies are insufficient. Here we show the tumor promoting function of PIERCE1 in the KRAS-mutant NSCLC. Mechanistically, PIERCE1 depletion inhibits cell growth and AKT phosphorylation (pAKT) at S473, particularly in KRAS-mutant lung cancer. Analyses of AKT-related genes show that PIERCE1 negatively regulates gene expression of AKT suppressor TRIB3 through CHOP pathway. Correspondingly, four independent in vivo approaches in lung cancer mouse models related to KRAS mutations reveal the tumor suppressive effect of PIERCE1 depletion suggesting its therapeutic potential. Tissue microarray of human lung cancer showed that PIERCE1 is expressed in 83% of lung cancers and is linked to pAKT expression. This illustrates how PIERCE1 depletion acts as a novel therapeutics against KRAS-mutant NSCLC.
Project description:A new subset of pulmonary NSCLC patients can be defined as negative for C/EBP alpha and positive for Bmi-1 expression, which are mimicked by our lung-specific C/EBP alpha null mice. Bmi-1 activity is required for both tumor initiation and maintenance in the C/EBP alpha null background and pharmacological inhibition of Bmi-1 exhibits anti-tumor effect. Overall, we show that C/EBP alpha is a tumor-suppressor gene in lung, and that Bmi-1 is involved in mediating the oncogenic process downstream of C/EBP alpha, implying that Bmi-1 inhibition may offer a therapeutic advantage for the subset of patients with low levels of C/EBP alpha expression.
Project description:Non-small cell lung cancer (NSCLC) cell lines are widely used model systems to study molecular aspects of lung cancer. Comparative and in-depth proteome expression data across many NSCLC cell lines has not been generated yet, but would be of utility for the investigation of candidate targets and markers in oncogenesis. We employed a SILAC reference approach to perform replicate proteome quantifications across 23 distinct NSCLC cell lines. On average, close to 4000 distinct proteins were identified and quantified per cell line. These included many known targets and diagnostic markers, indicating that our proteome expression data represents a useful resource for NSCLC pre-clinical research. To assess proteome diversity within the NSCLC cell line panel, we performed hierarchical clustering and principal component analysis of proteome expression data. Our results indicate that general proteome diversity among NSCLC cell lines supersedes potential effects common to K-Ras or epidermal growth factor receptor (EGFR) oncoprotein expression. However, we observed partial segregation of EGFR or KRAS mutant cell lines for certain principal components, which reflected biological differences according to gene ontology enrichment analyses. Moreover, statistical analysis revealed several proteins that were significantly overexpressed in KRAS or EGFR mutant cell lines. Biological significance Despite enormous progress in molecular characterization and targeted therapy NSCLC represents a major cause for cancer-related deaths. While pre-clinical models such as NSCLC cell lines have been studied on the genomic and transcriptional level, proteome composition is poorly characterized. We conducted quantitative profiling across 23 NSCLC cell lines and studied global proteome diversity in relation to the presence of oncogenic KRAS or EGFR mutations. Notably, in-depth bioinformatics analysis pointed to prominent biological processes as well as up-regulated proteins in KRAS and EGFR mutant cells, highlighting the utility of cancer cell proteomics to identify target or biomarker candidates in the context of specific oncogenic mechanisms.
Project description:The identification of novel therapeutic strategies to overcome the intrinsic or acquired resistance to trametinib in mutant KRAS lung adenocarcinoma (LUAD) is a major challenge. This study analyzes the effects of trametinib in Id1, a key factor involved in the oncogenic KRAS pathway, and investigates the Id1 role in acquire resistance and synergy with immunotherapy in KRAS-driven LUAD. Restoring the antitumor immune response by blocking programmed-cell death protein 1 (PD-1) and programmed-cell death-ligand 1 (PD-L1) pathway represents a major breakthrough in non-small-cell lung cancer (NSCLC) treatment. Nevertheless, a high proportion of LUAD patients with KRAS alterations remain refractory to this therapy. Material and Methods: To explore whether MEK1/2 inhibition reduces Id1 expression, in vitro and in vivo experiments were conducted in KRAS-mutant NSCLC cells and murine models. RNAseq analysis was performed to elucidate the pathways involved in Id1 inhibition. Apoptosis and PD-L1 expression was measured by flow cytometry. Synergy of trametinib combined with anti-PD1 was investigated in KRAS-mutant LUAD mouse models. Results: Using preclinical syngeneic KRAS-mutant lung cancer mouse models, we demonstrate that trametinib synergizes with PD-1 blockade to reduce lung cancer progression and increase mice overall survival. This antitumor activity was linked to the degradation of Id1 via proteasome, and an enhanced INF-Y-mediated PD-L1 tumor cell expression in KRAS-mutant tumor cells. This effect required CD8+ T cells, boosted the intratumoral CD8+/Treg ratio, reducing the intratumoral Treg/CD4+ ratio. Conclusions: Our data may support the role of Id1 in the trametinib antitumoral effect, sustaining the mitogen-activated protein kinases (MAPK) signaling pathway involved in the trametinib acquired resistance cells and sensitizing KRAS-mutant lung tumors to PD-1 inhibitors, through PD-L1 overexpression.
Project description:Mutations in STK11/LKB1 in non-small cell lung cancer (NSCLC) are associated with poor patient responses to immune checkpoint blockade (ICB) and introduction of a Stk11/Lkb1 (L) mutation into murine lung adenocarcinomas driven by mutant Kras and Trp53 loss (KP) resulted in an ICB refractory syngeneic KPL tumor. Mechanistically this occurred because KPL mutant NSCLCs lacked TCF1-expressing CD8 T cells, a phenotype recapitulated in human STK11/LKB1 mutant NSCLCs. Systemic inhibition of Axl results in increased type I interferon secretion from dendritic cells that expanded tumor-associated TCF1+ PD-1+ CD8 T cells, restoring therapeutic response to PD-1 ICB for KPL tumors. This was observed in syngeneic immunocompetent mouse models and in humanized mice bearing STK11/LKB1 mutant NSCLC human tumor xenografts. NSCLC patients with identified STK11/LKB1 mutations receiving bemcentinib and pembrolizumab demonstrated objective clinical response to combination therapy. We conclude that AXL is a critical targetable driver of immune suppression in STK11/LKB1 mutant NSCLC.
Project description:Mutant KRAS (mut-KRAS) is present in 30% of all human cancers and plays a critical role in cancer cell growth and resistance to therapy. There is evidence from colon cancer that mut-KRAS is a poor prognostic factor and negative predictor of patient response to molecularly targeted therapy. However, evidence for such a relationship in non small cell lung cancer (NSCLC) is conflicting. KRAS mutations are primarily found at codons 12 and 13, where different base changes lead to alternate amino acid substitutions that lock the protein in an active state. The patterns of mut-KRas amino acid substitutions in colon cancer and NSCLC are quite different, with aspartate (D) predominating in colon cancer (50%) and cysteine (C) in NSCLC (47%). Through an analysis of a recently completed biopsy biomarker-driven, molecularly targeted multi-arm trial of 215 evaluable patients with refractory NSCLC we show that mut-KRas-G12C/V but not total mut-KRAS predicts progression free survival for the overall group, and for the sorafenib and vandetanib treatment arms. Transcriptome microarray data shows differential expression of cell cycle genes between mut-KRas-G12C/V and G12D patient tumors. A panel of NSCLC cell lines with known mut-KRas amino acid substitutions was used to identify pathways activated by the different mut-KRas, showing that mut-KRas-G12D activates both PI-3-K and MEK signaling, while mut-KRas G12C does not, and alternatively activates RAL signaling. This finding was confirmed using immortalized human bronchial epithelial cells stably transfected with wt-KRAS and different forms of mut-KRAS. Molecular modeling studies show that the different conformation imposed by mut-KRas-G12C could lead to altered association with downstream signaling transducers compared to wild type and mut-KRas-G12D. The significance of the findings for developing mut-KRAS therapies is profound, since it suggests that not all mut-KRas amino acid substitutions signal to effectors in a similar way, and may require different therapeutic interventions. Gene expression profiles were measured in 22 core biopsies from patients with refractory non-small cell lung cancer included in the Biomarker-integrated Approaches of Targeted Therapy for Lung Cancer Elimination (BATTLE). All tumors were KRAS mutants, but with different patterns of amino acid substitutions. Supervised analysis of transcriptome profiling was performed to compare cysteine or valine KRAS mutants with other KRAS mutants.