RAF1-MEK1-ERK/AKT axis may confer NSCLC cell lines resistance to erlotinib.
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ABSTRACT:
SUBMITTER: Xu ZH
PROVIDER: S-EPMC3726964 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:ObjectivesEpidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) has significant therapeutic efficacy in non-small-cell lung cancer (NSCLC) patients. However, acquired resistance is inevitable and limits the long-term efficacy of EGFR-TKI. Our study aimed to investigate the role of ras-associated binding protein 25 (Rab25) in mediating EGFR-TKI resistance in NSCLC.Materials and methodsRab25 expression in NSCLC patients was measured by immunohistochemical staining. Western blotting was used to analyse the expression of molecules in the Rab25, EGFR and Wnt signalling pathways. Lentiviral vectors were constructed to knock in and knock out Rab25. The biological function of Rab25 was demonstrated by cell-counting kit-8 and flow cytometry. The interaction between Rab25 and β1 integrin was confirmed by co-immunoprecipitation.ResultsRab25 overexpression induced erlotinib resistance, whereas Rab25 knockdown reversed this refractoriness in vitro and in vivo. Moreover, Rab25 interacts with β1 integrin and promotes its trafficking to the cytoplasmic membrane. The membrane-β1 integrin induced protein kinase B (AKT) phosphorylation and subsequently activated the Wnt/β-catenin signalling pathway, promoting cell proliferation. Furthermore, high Rab25 expression was associated with poor response to EGFR-TKI treatment in NSCLC patients.ConclusionsRab25 mediates erlotinib resistance by activating the β1 integrin/AKT/β-catenin signalling pathway. Rab25 may be a predictive biomarker and has potential therapeutic value in NSCLC patients with acquired resistance to EGFR-TKI.
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Project description:Genetic alterations that activate the mitogen-activated protein kinase (MAP kinase) pathway occur commonly in cancer. For example, the majority of melanomas harbor mutations in the BRAF oncogene, which are predicted to confer enhanced sensitivity to pharmacologic MAP kinase inhibition (e.g., RAF or MEK inhibitors). We investigated the clinical relevance of MEK dependency in melanoma by massively parallel sequencing of resistant clones generated from a MEK1 random mutagenesis screen in vitro, as well as tumors obtained from relapsed patients following treatment with AZD6244, an allosteric MEK inhibitor. Most mutations conferring resistance to MEK inhibition in vitro populated the allosteric drug binding pocket or alpha-helix C and showed robust ( approximately 100-fold) resistance to allosteric MEK inhibition. Other mutations affected MEK1 codons located within or abutting the N-terminal negative regulatory helix (helix A), which also undergo gain-of-function germline mutations in cardio-facio-cutaneous (CFC) syndrome. One such mutation, MEK1(P124L), was identified in a resistant metastatic focus that emerged in a melanoma patient treated with AZD6244. Both MEK1(P124L) and MEK1(Q56P), which disrupts helix A, conferred cross-resistance to PLX4720, a selective B-RAF inhibitor. However, exposing BRAF-mutant melanoma cells to AZD6244 and PLX4720 in combination prevented emergence of resistant clones. These results affirm the importance of MEK dependency in BRAF-mutant melanoma and suggest novel mechanisms of resistance to MEK and B-RAF inhibitors that may have important clinical implications.
| S-EPMC2777185 | biostudies-literature
Project description:Background: The efficacy of an EGFR-targeted treatment strategy for non-small cell lung cancer (NSCLC) is reduced by drug resistance. IL-22 enhances tumor growth and induces chemotherapy resistance in human lung cancer cells. The present study elucidated the IL-22-induced mechanism underlying EGFR-tyrosine kinase inhibitor (TKI) resistance in NSCLC. Methods: The plasma and tissues of patients who received EGFR-TKIs were utilized to determine the association between IL-22 expression and gefitinib efficacy. The IL-22 effect on the EGFR/ERK/AKT pathways in NSCLC HCC827 and PC-9 cells was determined using the CCK-8 assay, western blot, and flow cytometric analysis. A PC-9 xenograft model of IL-22 exposure was established. Gefitinib was administered to mice in combination with IL-22 or vehicle. Results: We showed that IL-22 expression was higher in the EGFR-TKI-resistant group compared to EGFR-TKI-sensitive group. IL-22 expression was associated with EGFR-TKI efficacy in plasma. Additional treatment of IL-22 induced gefitinib resistance and reduced apoptosis in PC-9 and HCC827 cell lines. Furthermore, we showed that the effects of IL-22 attributed to p-ERK, p-EGFR, and p-AKT up-regulation. IL-22 neutralizing antibody completely abrogated the effects of IL-22 on apoptosis and AKT/EGFR/ERK signaling. Finally, we showed that IL-22 enhanced tumor growth and induced gefitinib resistance in the PC-9 xenograft model. Moreover, compared with gefitinib alone, the combination of IL-22 and gefitinib led to an increase in Ki67-positive staining and a reduction in TUNEL staining. Conclusions: Our findings indicate that IL-22 plays a role in tumor progression and EGFR-TKI resistance in NSCLC. Thus, IL-22 might serve as a novel biomarker to overcome resistance of EGFR-TKI.
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Project description:Background Hepatocellular carcinoma (HCC) is a common lethal malignant tumor worldwide. Circular RNAs (circRNAs) have been reported to affect the development of human cancers, including HCC. In this project, we aim to clarify the functional effect of circular CDR1as (circ_CDR1as) on HCC progression. Methods Quantitative real-time polymerase chain reaction (qRT-PCR) or Western blot is implemented to detect the expression of circ_CDR1as, microRNA (miR)-1287 and Raf-1 proto-oncogene, serine/threonine kinase (Raf1). Cell proliferation is assessed via colony formation and 3-(4, 5)-dimethylthiazole-2-y1)-2, 5-biphenyl tetrazolium bromide (MTT) assays. Cell migration and invasion are measured by Transwell assay. The target relationship between miR-1287 and circ_CDR1as or Raf1 is validated through dual-luciferase reporter assay. The levels of epithelia–mesenchymal transition (EMT) markers and the MEK/ERK signal pathway-related proteins are examined by Western blot. Model in nude mice is constructed to determine the role of circ_CDR1as in vivo. Results Expression of circ_CDR1as and Raf1 is elevated, while miR-1287 expression is decreased in HCC. Depletion of circ_CDR1as or Raf1 could inhibit proliferation and metastasis of HCC cells. Besides, circ_CDR1as regulates Raf1 expression by targeting miR-1287. MiR-1287 upregulation or Raf1 depletion could partially counterbalance circ_CDR1as depletion-mediated inhibitory effects on HCC cell behaviors. Moreover, circ_CDR1as depletion represses HCC progression through inactivating MEK/ERK pathway. In addition, circ_CDR1as depletion suppresses tumor growth in vivo via regulating miR-1287/Raf1 pathway. Conclusion Circ_CDR1as depletion inhibits HCC cell proliferation and metastasis by miR-1287/Raf1 and MEK/ERK pathways, highlighting a promising molecular target for HCC treatment.
| S-EPMC7522432 | biostudies-literature
Project description:Backgroundp21-activated kinase 1 (PAK1) plays a fundamental role in promoting the development and progression of several cancers and is a potential therapeutic target. However, the biological function and underlying mechanism of PAK1 in esophageal squamous cell carcinoma (ESCC) remain unclear.MethodsThe expression of PAK1 was detected in both ESCC cell lines and clinical samples. Cell growth was measured by MTT, focus formation and soft agar assays. Cell migration and invasion were detected by wound healing and transwell assays. Animal models of subcutaneous tumourigenicity and tail vein metastasis were performed to determine the inhibitory effect of pharmacological inhibitor IPA-3 on tumor growth and metastasis of ESCC cells.ResultsWe found that PAK1 was frequently overexpressed in ESCC. Ectopic expression of PAK1 promoted cellular growth, colony formation and anchorage-independent growth. Overexpressing PAK1 also enhanced migration, invasion and the expression of MMP-2 and MMP-9 in ESCC cells. In contrast, silencing PAK1 by lentiviral knockdown or a specific inhibitor IPA-3 resulted in a contrary effect. Subsequent investigations revealed that Raf1/MEK1/ERK signaling pathway was involved in PAK1-mediated effect. Enhanced expression of Raf1 attenuated the inhibitory functions of PAK1 shRNA. Whereas blocking of Raf1 by shRNA or specific inhibition of MEK1 by U0126 antagonized the oncogenetic effect of PAK1 on ESCC cells. More importantly, Pharmacological inhibition of PAK1 by IPA-3 significantly suppressed tumor growth and lung metastasis of ESCC cells in vivo.ConclusionsThese data support that PAK1 is an ideal target for the development of potential therapeutic drugs for ESCC patients even with metastasis.
| S-EPMC6458688 | biostudies-literature
Project description:PurposeAcquired resistance to erlotinib in patients with EGFR-mutant non-small cell lung cancer can result from aberrant activation of alternative receptor tyrosine kinases, such as the HGF-driven c-MET receptor. We sought to determine whether inhibition of AKT signaling could augment erlotinib activity and abrogate HGF-mediated resistance.MethodsThe effects of MK-2206, a selective AKT inhibitor, were evaluated in combination with erlotinib on a large panel of 13 lung cancer cell lines containing different EGFR or KRAS abnormalities. The activity of the combination was assessed using proliferation assays, flow cytometry and immunoblotting. The MEK inhibitor PD0325901 was used to determine the role of the MAP kinase pathway in erlotinib resistance.ResultsThe combination of MK-2206 and erlotinib resulted in synergistic growth inhibition independent of EGFR mutation status. In cell lines where HGF blocked the anti-proliferative and cytotoxic effects of erlotinib, MK-2206 could restore cell cycle arrest, but MEK inhibition was required for erlotinib-dependent apoptosis. Both AKT and MEK inhibition contributed to cell death independent of erlotinib in the T790M-containing H1975 and the EGFR-WT cell lines tested.ConclusionsThese findings illustrate the potential advantages and challenges of combined signal transduction inhibition as a generalized strategy to circumvent acquired erlotinib resistance.
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Project description:Pancreatic cancer is a lethal disease with a high metastatic potential. In our previous study, we identified a specific subgroup of patients with pancreatic cancer with a serum signature of carcinoembryonic antigen (CEA)+/cancer antigen (CA)125+/CA19-9 ≥1,000 U/ml. In this study, by using high-throughput screening analysis, we found that receptor-interacting protein kinases 4 (RIPK4) may be a key molecule involved in the high metastatic potential of this subgroup of patients with pancreatic cancer. A high RIPK4 expression predicted a poor prognosis and promoted pancreatic cancer cell migration and invasion via the RAF1/MEK/ERK pathway. Moreover, RIPK4 activated the RAF1/MEK/ERK pathway by regulating proteasome-mediated phosphatidylethanolamine binding protein 1 (PEBP1) degradation. The suppression of PEBP1 degradation eliminated the RIPK4-induced activation of RAF1/MEK/ERK signaling and pancreatic cancer cell migration or invasion. Thus, on the whole, the findings of this study indicated that RIPK4 was upregulated in the subgroup of pancreatic cancer with a high metastatic potential. RIPK4 overexpression promoted pancreatic cancer cell migration and invasion via the PEBP1 degradation-induced activation of the RAF1/MEK/ERK pathway.
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Project description:Arterial morphogenesis is one of the most critical events during embryonic vascular development. Although arterial fate specification is mainly controlled by the Notch signaling pathway, arterial-venous patterning is modulated by a number of guidance factors. How these pathways are regulated is still largely unknown. Here, we demonstrate that endothelial activation of RAF1/extracellular signal-regulated kinase (ERK) pathway regulates arterial morphogenesis and arterial-venous patterning via ?/Notch and semaphorin signaling. Introduction of a single amino acid RAF1 mutant (RAF1 Ser259Ala), which renders it resistant to inhibition by phosphorylation, into endothelial cells in vitro induced expression of virtually the entire embryonic arteriogenic program and activated semaphorin 6A-dependent endothelial cell-cell repulsion. In vivo, endothelial-specific expression of RAF1(S259A) during development induced extensive arterial morphogenesis both in the yolk sac and the embryo proper and disrupted arterial-venous patterning. Our results suggest that endothelial ERK signaling is critical for both arteriogenesis and arterial-venous patterning and that RAF1 Ser(259) phosphorylation plays a critical role in preventing unopposed ERK activation.
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Project description:Infection and inflammation serve an important role in tumor development. Toll‑like receptor 4 (TLR4) is a pivotal component of the innate and adaptive immune response during infection and inflammation. Programmed‑death ligand 1 (PD‑L1) is hypothesized as an important factor for non‑small cell lung cancer (NSCLC) immune escape. In the present study, the relationship between TLR4 and PD‑L1, in addition to the associated molecular mechanism, were investigated. TLR4 and PD‑L1 expression in lung cancer tissues were detected using immunohistochemistry, whilst overall patient survival was measured using the Kaplan‑Meier method. The A549 cell line stimulated using lipopolysaccharide (LPS) was applied as the in vitro inflammatory NSCLC model. Associated factors were investigated using reverse transcription‑quantitative PCR and western blotting. Lung cancer tissues exhibited increased PD‑L1 and TLR4 levels compared with those of adjacent para‑cancerous tissues, where there was a positive correlation between TLR4 and PD‑L1 expression. In addition, increased expression of these two proteins was found to be linked with poorer prognoses. Following the stimulation of A549 cells with LPS, TLR4 and PD‑L1 expression levels were revealed to be upregulated in a dose‑dependent manner, where the ERK and PI3K/AKT signaling pathways were found to be activated. Interestingly, in the presence of inhibitors of these two pathways aforementioned, upregulation of PD‑L1 expression was only inhibited by the MEK inhibitor PD98059, which can inhibit ERK activity. These data suggested that the ERK signaling pathway is necessary for the TLR4/PD‑L1 axis. In conclusion, data from the present study suggest that TLR4 and PD‑L1 expression can serve as important prognostic factors for NSCLC, where TLR4 activation may induce PD‑L1 expression through the ERK signaling pathway.
| S-EPMC7307593 | biostudies-literature
Project description:Histiocytic neoplasms are clonal disorders of the monocyte/macrophage lineage defined by mutations activating MAP kinase signaling, including BRAFV600E mutations in ~50% of patients, which confer robust responses to BRAF inhibition. More recently, the MEK inhibitor cobimetinib was FDA-approved for BRAFV600-wild-type histiocytosis patients. Here following genomic analysis of 500 pediatric and adult patients with diverse histiocytoses, the most common alteration following BRAFV600E was MEK1E102_I103 in-frame deletion. MEK1E102_I103del and related RAF-independent MEK mutants were associated with an aggressive multi-system clinical phenotype with worse progression-free survival with MEK inhibition as compared to patients with other classes of MEK1/2 mutations. Given that cancer-associated MEK1/2 mutations have not been modeled in vivo and the clinical importance of MEK1 mutations in histiocytoses, we generated MEK1E102_I103del conditional knock-in mice. Using three distinct hematopoietic Cre drivers, these mice developed a 100% penetrant, lethal disorder by 6 weeks of age with expansion of classical and non-classical monocytes, macrophages, and Cd11b+ conventional dendritic cells which infiltrated hematopoietic organs, liver, and skin. MEK1-mutant mice were sensitive to single-agent treatment with the oral ERK inhibitor ulixertinib. We consequently treated five MEK1E102_I103del-mutant patients with ulixertinib on prospective IRB-approved Single Patient Use Expanded Access protocols, four of whom had disease refractory to MEK inhibition. Four of five patients experienced objective clinical and/or radiological responses to ulixertinib. These data reveal the impact of oncogenic MEK kinase mutations in vivo, identify patients with likelihood of resistance to MEK inhibition, and nominate ERK inhibition as a therapeutic approach to overcome resistance to MEK inhibition in histiocytoses.
2024-09-03 | GSE268618 | GEO