Mediator Kinase Inhibition Impedes Transcriptional Plasticity and Prevents Resistance to Sustained MAPK-Targeted Therapy in KRAS-Mutant Cancers
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA981152 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR24865901.fastq.gz | Fastqsanger.gz | |||
| SRR24865902.fastq.gz | Fastqsanger.gz | |||
| SRR24865903.fastq.gz | Fastqsanger.gz | |||
| SRR24865904.fastq.gz | Fastqsanger.gz | |||
| SRR24865905.fastq.gz | Fastqsanger.gz |
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Project description:Acquired resistance remains a major challenge for therapies targeting oncogene activated pathways. KRAS, for example, 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 second-generation MAPK inhibitors across KRAS-mutant pancreatic, colorectal, and lung cancers, 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 tumor-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 sustained 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, tumor-specific resistance programs.
2024-06-26 | GSE234378 | GEO
Project description:Mediator Kinase Inhibition Impedes Transcriptional Plasticity and Prevents Resistance to ERK/MAPK-Targeted Therapy in KRAS-Mutant Cancers
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Project description: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 tumor-specific. Transcriptional reprogramming extends beyond the well-established early response, and instead represents a dynamic, evolved population-level 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, tumor-specific resistance programs.
2024-05-15 | GSE237177 | GEO
Project description:Mutational activation of KRAS represents a common oncogenic event in lung cancers and still lacks effective treatments so far. Here, we identify the proto-oncogene B-cell lymphoma 6 (BCL6) as a lynchpin for KRAS dependence. BCL6 transcription was markedly promoted upon inducible activation of KRAS in either LSL-KrasG12D mice lung tumor tissue or engineered KRAS isogenic cell lines. Constitutive expression of BCL6 was also observed in patients with KRAS-mutant lung adenocarcinoma and associated with poor survival. Employing chemical and genetic screens, we characterized that the MAPK/ELK1 axis downstream of KRAS directly regulated BCL6 expression. Genetic depletion or pharmacological inhibitor targeting BCL6 preferentially impedes the proliferation of KRAS-mutant lung cancer cells by suppressing pre-RC protein expression in cycling cells, ultimately leading to stalled replication and DNA damage in vitro. Accordingly, targeted inhibition of BCL6 significantly reduced tumor burden and mortality in LSL-KrasG12D/+ and patient-derived lung cancer xenograft mouse models in vivo. Taken together, these findings reveal an oncogenic role of BCL6 in promoting KRAS-addicted lung cancers and define that BCL6 inhibition confers a targetable vulnerability for this kind of disease.
2022-10-19 | GSE189545 | GEO
Project description: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.
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2025-08-23 | PXD047272 | Pride
Project description:Pancreatic cancer is characterised by the prevalence of oncogenic mutations in KRAS. Previous studies have reported that altered Kras gene dosage drives progression and metastatic incidence in pancreatic cancer. While the role of oncogenic KRAS mutation is well characterised, the relevance of the partnering wild-type KRAS allele in pancreatic cancer is less well understood and controversial. Using in vivo mouse modelling of pancreatic cancer, we demonstrate that wild-type Kras restrains the oncogenic impact of mutant Kras, and drastically impacts both Kras-mediated tumourigenesis and therapeutic response. Mechanistically, deletion of wild-type Kras increases oncogenic Kras signalling through the downstream MAPK effector pathway, driving pancreatic intraepithelial neoplasia (PanIN) initiation. In addition, in the KPC mouse model, a more aggressive model of pancreatic cancer, loss of wild-type KRAS leads to accelerated initiation but delayed tumour progression. These tumours had altered stroma, downregulated Myc levels and an enrichment for immunogenic gene signatures. Importantly, loss of wild-type Kras sensitises Kras mutant tumours to MEK1/2 inhibition though tumours eventually become resistant and then rapidly progress. This study demonstrates the repressive role of wild-type Kras during pancreatic tumourigenesis and highlights the critical impact of the presence of wild-type KRAS on tumourigenesis and therapeutic response in pancreatic cancer.
2024-09-22 | GSE277392 | GEO
Project description:KRAS, mutated in ~30% of all cancers, activates the RAF-MEK-ERK signaling cascade. It has previously been shown that CRAF is required for growth of KRAS mutant lung tumors but the requirement for CRAF kinase activity is unknown. Here, we show that subsets of KRAS mutant tumors are dependent on CRAF for growth. Kinase-dead but not dimer-defective CRAF rescued growth inhibition suggesting that dimerization but not kinase activity is required. Quantitative proteomics demonstrated enrichment of CRAF:ARAF dimers in KRAS mutant cells and depletion of both CRAF and ARAF rescued the CRAF loss phenotype. Mechanistically, CRAF depletion caused sustained ERK activation and induction of cell cycle arrest. Treatment with low dose MEK or ERK inhibitor rescued the CRAF loss phenotype. Our studies highlight the role of CRAF in regulating MAPK signal intensity to promote tumorigenesis downstream of mutant KRAS and suggest that disrupting dimerization or degrading CRAF may have therapeutic benefit.
2021-10-29 | MSV000088285 | MassIVE
Project description:Background: Osteosarcoma, a primary malignant bone tumor predominantly affecting children and adolescents, exhibits a dismal prognosis for patients with metastatic or recurrent disease, characterized by low five-year survival rates. This poor outcome is largely attributed to the incomplete understanding of the molecular mechanisms governing osteosarcoma aggressiveness and metastasis, coupled with a paucity of effective early diagnostic biomarkers and targeted therapeutic strategies. Consequently, elucidating the critical molecular events driving osteosarcoma pathogenesis and identifying novel biomarkers are of paramount importance for improving patient outcomes. Prior research has demonstrated aberrant expression of Zinc Finger DHHC-Type Palmitoyltransferase 9 (ZDHHC9) in various malignancies, but its specific function and clinical significance in osteosarcoma remain poorly defined. Methods: This study employed a comprehensive approach integrating bioinformatic analyses and experimental validation to investigate the functional role and clinical relevance of ZDHHC9 in osteosarcoma. Bioinformatic analyses (TIMER, GEPIA, TCGA databases) were utilized to examine ZDHHC9 expression across a pan-cancer landscape and its association with survival in osteosarcoma patients. Immunohistochemistry (IHC) and Western blotting were employed to analyze ZDHHC9 expression in clinical osteosarcoma specimens and cell lines. In vitro assays (CCK-8, colony formation, wound healing, Transwell, flow cytometry, and Western blotting) were performed to evaluate the impact of ZDHHC9 on osteosarcoma cell proliferation, migration, and invasion. Proteomic sequencing, molecular docking, and co-immunoprecipitation (Co-IP) experiments were conducted to explore the interaction between ZDHHC9 and KRAS. Western blotting was used to analyze the regulation of Raf1, ERK1/2, and p-ERK1/2 expression by ZDHHC9 and KRAS. Finally, a xenograft model was employed to assess the effect of ZDHHC9 on in vivo tumor growth. Results: Bioinformatic analyses revealed that elevated ZDHHC9 expression correlates with poor prognosis in osteosarcoma. IHC and Western blotting confirmed significantly increased ZDHHC9 expression in osteosarcoma tissues compared to adjacent non-tumorous tissues. Upregulation of ZDHHC9 was significantly associated with elevated Ki67 levels and advanced Enneking stage, suggesting a link to tumor aggressiveness. In vitro studies demonstrated that downregulation of ZDHHC9 suppressed osteosarcoma cell proliferation, migration, and invasion, while promoting apoptosis. Conversely, upregulation of ZDHHC9 elicited opposite effects. Proteomic sequencing revealed that ZDHHC9 knockdown significantly downregulated the expression of proteins associated with the RAS/MAPK signaling pathway. Functional experiments showed that overexpression of KRAS partially abrogated the inhibitory effects of ZDHHC9 knockdown on cell proliferation, migration, and invasion. Molecular docking and Co-IP experiments confirmed a specific interaction between ZDHHC9 and KRAS, leading to activation of the RAS/MAPK signaling pathway. Conclusion: ZDHHC9 promotes osteosarcoma cell proliferation, migration, and invasion by enhancing KRAS-mediated activity of the RAS/MAPK signaling pathway, which promotes cell cycle progression while inhibiting apoptosis.
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