Dataset Information

Cyclooxygenase-2 Influences Response to Cotargeting of MEK and CDK4/6 in a Subpopulation of Pancreatic Cancers.

ABSTRACT: The ineffectiveness of chemotherapy in patients with pancreatic cancer highlights a critical unmet need in pancreatic cancer therapy. Two commonly mutated genes in pancreatic cancer, KRAS and CDKN2A, have an incidence exceeding 90%, supporting investigation of dual targeting of MEK and CDK4/6 as a potential therapeutic strategy for this patient population. An in vitro proliferation synergy screen was conducted to evaluate response of a panel of high passage and patient-derived pancreatic cancer models to the combination of trametinib and palbociclib to inhibit MEK and CDK4/6, respectively. Two adenosquamous carcinoma models, L3.6pl and UM59, stood out for their high synergy response. In vivo studies confirmed that this combination treatment approach was highly effective in subcutaneously implanted L3.6pl and UM59 tumor-bearing animals. Both models were refractory to single-agent treatment. Reverse-phase protein array analysis of L3.6pl tumors excised from treated animals revealed strong downregulation of COX-2 expression in response to combination treatment. Expression of COX-2 under a CMV-driven promoter and shRNA knockdown of COX-2 both led to resistance to combination treatment. Our findings suggest that COX-2 may be involved in the improved therapeutic outcome seen in some pancreatic tumors that fail to respond to MEK or CDK4/6 inhibitors alone but respond favorably to their combination.

SUBMITTER: Maust JD

PROVIDER: S-EPMC6279520 | biostudies-literature | 2018 Dec

REPOSITORIES: biostudies-literature

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Cyclooxygenase-2 Influences Response to Cotargeting of MEK and CDK4/6 in a Subpopulation of Pancreatic Cancers.

Maust Joel D JD Frankowski-McGregor Christy L CL Bankhead Armand A Simeone Diane M DM Sebolt-Leopold Judith S JS

Molecular cancer therapeutics 20180925 12

The ineffectiveness of chemotherapy in patients with pancreatic cancer highlights a critical unmet need in pancreatic cancer therapy. Two commonly mutated genes in pancreatic cancer, KRAS and CDKN2A, have an incidence exceeding 90%, supporting investigation of dual targeting of MEK and CDK4/6 as a potential therapeutic strategy for this patient population. An in vitro proliferation synergy screen was conducted to evaluate response of a panel of high passage and patient-deriv ...[more]

PMID: 30254182

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Project description:Pancreatic cancer is an increasing cause of cancer related death worldwide. KRAS is the dominant oncogene in this cancer type and molecular rationale would indicate, that inhibitors of the downstream target MEK could be appropriate targeted agents, but clinical trials have failed so far to achieve statistically significant benefit in unselected patients. We aimed to identify predictive molecular biomarkers that can help to define subgroups where MEK inhibitors might be beneficial alone or in combination. Next-generation sequencing data of 50 genes in three pancreatic cancer cell lines (MiaPaCa2, BxPC3 and Panc1) were analyzed and compared to the molecular profile of 138 clinical pancreatic cancer samples to identify the molecular subtypes of pancreatic cancer these cell lines represent. Luminescent cell viability assay was used to determine the sensitivity of cell lines to kinase inhibitors. Western blot was used to analyze the pathway activity of the examined cell lines. According to our cell viability and pathway activity data on these model cell lines only cells harboring the rare G12C KRAS mutation and low EGFR expression are sensitive to single MEK inhibitor (trametinib) treatment. The common G12D KRAS mutation leads to elevated baseline Akt activity, thus treatment with single MEK inhibitors fails. However, combination of MEK and Akt inhibitors are synergistic in this case. In case of wild-type KRAS and high EGFR expression MEK inhibitor induced Akt phosphorylation leads to trametinib resistance which necessitates for MEK and EGFR or Akt inhibitor combination treatment. In all we provide strong preclinical rational and possible molecular mechanism to revisit MEK inhibitor therapy in pancreatic cancer in both monotherapy and combination, based on molecular profile analysis of pancreatic cancer samples and cell lines. According to our most remarkable finding, a small subgroup of patients with G12C KRAS mutation may still benefit from MEK inhibitor monotherapy.

Project description:Pancreatic ductal adenocarcinoma (PDAC) is not sensitive to most chemotherapy drugs, leading to poor chemotherapy efficacy. Recently, Trametinib and Palbociclib have promising prospects in the treatment of pancreatic cancer. This article aims to explore the effects of Trametinib on pancreatic cancer and address the underlying mechanism of resistance as well as its reversal strategies. The GDSC (Genomics of Drug Sensitivity in Cancer) and CTD2 (Cancer Target Discovery and Development) were utilized to screen the potential drug candidate in PDAC cell lines. The dose-increase method combined with the high-dose shock method was applied to induce the Trametinib-resistant PANC-1 and MIA PaCa-2 cell lines. The CCK8 proliferation assay, colony formation assay, flow cytometry, and western blot were conducted to verify the inhibitory effect of Trametinib and Palbociclib. RNA-seq was performed in resistant PDAC cell lines to find the differential expression genes related to drug resistance and predict pathways leading to the reversal of Trametinib resistance. The GDSC and CTD2 database screening revealed that Trametinib demonstrates a significant inhibitory effect on PDAC. We found that Trametinib has a lower IC50 than Gemcitabine in PDAC cell lines. Both Trametinib and Gemcitabine can decrease the proliferation capacity of pancreatic cells, induce cell cycle arrest, and increase apoptosis. Simultaneously, the phosphorylation of the AKT and ERK pathways were inhibited by the treatment of Trametinib. In addition, the RNA-seq of Trametinib-induced resistance PDAC cell lines reveals that the cyclin-dependent kinase (CDK)-RB-E2F regulatory axis and G2/M DNA damage checkpoint might lead the drug resistance. Besides, the combination of Trametinib with Palbociclib could inhibit the proliferation and cell cycle of both resistant cells lines and also restore the sensitivity of drug-resistant cells to Trametinib. Last but not least, the interferon-α and interferon-γ expression were upregulated in resistance cell lines, which might lead to the reversal of drug resistance. The study shows Trametinib has a critical inhibitory effect on PDAC. Besides, the combination of Trametinib with Palbociclib can inhibit the proliferation of PDAC-resistant cells.

Dataset Information

Cyclooxygenase-2 Influences Response to Cotargeting of MEK and CDK4/6 in a Subpopulation of Pancreatic Cancers.

Publications

Cyclooxygenase-2 Influences Response to Cotargeting of MEK and CDK4/6 in a Subpopulation of Pancreatic Cancers.

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