Dataset Information

OXCT1 Enhances Gemcitabine Resistance Through NF-κB Pathway in Pancreatic Ductal Adenocarcinoma.

ABSTRACT:

Background

Pancreatic ductal adenocarcinoma (PDAC) is a type of malignant tumor with a five-year survival rate of less than 10%. Gemcitabine (GEM) is the most commonly used drug for PDAC chemotherapy. However, a vast majority of patients with PDAC develop resistance after GEM treatment.

Methods

We screened for GEM resistance genes through bioinformatics analysis. We used immunohistochemistry to analyze 3-oxoacid CoA-transferase 1 (OXCT1) expression in PDAC tissues. The survival data were analyzed using the Kaplan-Meier curve. The expression levels of the genes related to OXCT1 and the NF-κB signaling pathway were quantified using real-time quantitative PCR and western blot analyses. We performed flow cytometry to detect the apoptosis rate. Colony formation assay was performed to measure the cell proliferation levels. The cytotoxicity assays of cells were conducted using RTCA. The downstream pathway of OXCT1 was identified via the Gene Set Enrichment Analysis. Tumor growth response to GEM in vivo was also determined in mouse models.

Results

Bioinformatics analysis revealed that OXCT1 is the key gene leading to GEM resistance. Patients with high OXCT1 expression exhibited short relapse-free survival under GEM treatment. OXCT1 overexpression in PDAC cell lines exerted inhibitory effect on apoptosis after GEM treatment. However, the down-regulation of OXCT1 showed the opposite effect. Blocking the NF-κB signaling pathway also reduced GEM resistance of PDAC cells. Tumor growth inhibition induced by GEM in vivo reduced after OXCT1 overexpression. Moreover, the effect of OXCT1 on GEM refractoriness in PDAC cell lines was reversed through using an NF-κB inhibitor.

Conclusion

OXCT1 promoted GEM resistance in PDAC via the NF-κB signaling pathway both in vivo and in vitro. Our results suggest that OXCT1 could be used as a potential therapeutic target for patients with PDAC.

SUBMITTER: Ding J

PROVIDER: S-EPMC8602561 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:BACKGROUND & AIMS:Gemcitabine resistance is rapidly acquired by pancreatic ductal adenocarcinoma (PDAC) patients. Novel approaches that predict the gemcitabine response of patients and enhance gemcitabine chemosensitivity are important to improve patient survival. We aimed to identify genes as novel biomarkers to predict the gemcitabine response and the therapeutic targets to attenuate chemoresistance in PDAC cells. METHODS:Genome-wide RNA interference screening was conducted to identify genes that regulated gemcitabine chemoresistance. A cell proliferation assay and a tumor formation assay were conducted to study the role of lethal giant larvae homolog 1 (LLGL1) in gemcitabine chemoresistance. Levels of LLGL1 and its regulating targets were measured by immunohistochemical staining in tumor tissues obtained from patients who received gemcitabine as a single therapeutic agent. A gene-expression microarray was conducted to identify the targets regulated by LLGL1. RESULTS:Silencing of LLGL1 markedly reduced the gemcitabine chemosensitivity in PDAC cells. Patients had significantly shorter survival (6 months) if they bore tumors expressing low LLGL1 level than tumors with high LLGL1 level (20 months) (hazard ratio, 0.1567; 95% CI, 0.05966-0.4117). Loss of LLGL1 promoted cytokine receptor oncostatin M receptor (OSMR) expression in PDAC cells that led to gemcitabine resistance, while knockdown of OSMR effectively rescued the chemoresistance phenotype. The LLGL1-OSMR regulatory pathway showed great clinical importance because low LLGL1 and high OSMR expressions were observed frequently in PDAC tissues. Silencing of LLGL1 induced phosphorylation of extracellular signal-regulated kinase 2 and specificity protein 1 (Sp1), promoted Sp1 (pThr453) binding at the OSMR promoter, and enhanced OSMR transcription. CONCLUSIONS:LLGL1 possessed a tumor-suppressor role as an inhibitor of chemoresistance by regulating OSMR-extracellular signal-regulated kinase 2/Sp1 signaling. The data sets generated and analyzed during the current study are available in the Gene Expression Omnibus repository (ID: GSE64681).