Epigenetic activation of the elongator complex sensitizes gallbladder cancer to gemcitabine therapy

Abstract

Background Gallbladder cancer (GBC) is known for its high malignancy and multidrug resistance. Previously, we uncovered that impaired integrity and stability of the elongator complex leads to GBC chemotherapy resistance, but whether its restoration can be an efficient therapeutic strategy for GBC remains unknown. Methods RT-qPCR, MS-qPCR and ChIP-qPCR were used to evaluate the direct association between ELP5 transcription and DNA methylation in tumour and non-tumour tissues of GBC. EMSA, chromatin accessibility assays, and luciferase assays were utilized to analysis the DNA methylation in interfering PAX5-DNA interactions. The functional experiments in vitro and in vivo were performed to investigate the effects of DNA demethylating agent decitabine (DAC) on the transcription activation of elongator complex and the enhanced sensitivity of gemcitabine in GBC cells. Tissue microarray contains GBC tumour tissues was used to evaluate the association between the expression of ELP5, DNMT3A and PAX5. Results We demonstrated that transcriptional repression of ELP5 in GBC was highly correlated with hypermethylation of the promoter. Mechanistically, epigenetic analysis revealed that DNA methyltransferase DNMT3A-catalysed hypermethylation blocked transcription factor PAX5 activation of ELP5 by disrupting PAX5-DNA interaction, resulting in repressed ELP5 transcription. Pharmacologically, the DNA demethylating agent DAC eliminated the hypermethylated CpG dinucleotides in the ELP5 promoter and then facilitated PAX5 binding and reactivated ELP5 transcription, leading to the enhanced function of the elongator complex. To target this mechanism, we employed a sequential combination therapy of DAC and gemcitabine to sensitize GBC cells to gemcitabine-therapy through epigenetic activation of the elongator complex. Conclusions Our findings suggest that ELP5 expression in GBC is controlled by DNA methylation-sensitive induction of PAX5. The sequential combination therapy of DAC and gemcitabine could be an efficient therapeutic strategy to overcome chemotherapy resistance in GBC.

MiR-4733-5p promotes gallbladder carcinoma progression via directly targeting kruppel like factor 7

“…The relative gene expression was calculated using the comparative Ct method with ACTB or U6 as the control. Detail methods for RT-qPCR assay were described previously [ 14 ]. The primers used in this study were listed in Supplementary table 3.…”

Update on Chemoresistance Mechanisms to First-Line Chemotherapy for Gallbladder Cancer and Potential Reversal Strategies

“…The current chemotherapy drugs include cisplatin (CDDP), GEM, 5-fluorouracil (5-FU), epirubicin, oxaliplatin (OXA), S-1, capecitabine, and Irinotecan. 43,44 Clinical trial results indicate that the response rate of commonly used chemotherapy drug combinations remain low: 26.1%, 15.5%, 30.7%, 14.3%, and 29.8% for GEM+CDDP, GEM, GEM+OXA, 5-FU+FA, and GEM+S-1, respectively. 13,16,45 The response rate of GEM+CDDP as a first-line chemotherapy regimen (26.1%) was 10.6% higher than that of GEM alone (15.5%).…”

“…Hypermethylation of the ELP5 promoter is shown to inhibit ELP5 expression, while DNA demethylating agents sensitize GBC cells to GEM by inducing ELP5. 43 , 74 Some noncoding RNAs are also regulators of GBC-specific drug resistance. For example, long noncoding RNA-SSTR5-AS1 promotes GEM resistance in GBC by regulating NONO.…”

“…GBC has high rates of malignancy and multidrug resistance. The current chemotherapy drugs include cisplatin (CDDP), GEM, 5-fluorouracil (5-FU), epirubicin, oxaliplatin (OXA), S-1, capecitabine, and Irinotecan 43,44. Clinical trial results indicate that the response rate of commonly used chemotherapy drug combinations remain low: 26.1%, 15.5%, 30.7%, 14.3%, and 29.8% for GEM+CDDP, GEM, GEM+OXA, 5-FU+FA, and GEM+S-1, respectively 13,16,45…”

LncRNA SNHG6 Upregulates KPNA5 to Overcome Gemcitabine Resistance in Pancreatic Cancer via Sponging miR-944

“…Numerous studies illustrate the potential mechanisms underlying GEM resistance, among which epigenetic alterations have attracted increasing attention. Recently, long noncoding RNAs, circular RNAs, and other epigenetic modifications have been found to play key roles in GEM resistance [ 7 , 8 , 9 ]. It is well established that many mechanisms are closely involved in GEM resistance, in particular, the miRNA-related pathway is considered a pivotal mechanism in regulating GEM-resistant related pathways such as KRAS, PI3K-AKT, NF-kB, P53, and Hedgehog [ 10 , 11 ].…”