Xiao Chai Hu Tang alleviates the pancreatic tumorigenesis via improving the mtDNA N6-Methyladenine modification mediated mitochondrial dysfunction in Syrian hamster model

Abstract

Background: Pancreatic intraepithelial neoplasia (PanIN) is the most common precursor lesion of pancreatic ductal adenocarcinoma (PDAC), which is a highly malignant tumor and lack of effective treatment. Although Xiao Chai Hu Tang (XCHT) has a good therapeutic effect on pancreatic cancer patients with advanced stage, the effect and mechanism of XCHT remains unclear in pancreatic tumorigenesis.

Purpose: To assess the therapeutic effects of XCHT on the malignant transformation from PanIN to PDAC and to reveal its mechanisms of pancreatic tumorigenesis.

Methods: Syrian golden hamster were induced by N-Nitrosobis (2-oxopropyl) amine (BOP) to establish the pancreatic tumorigenesis model. The morphological changes of pancreatic tissue were observed by H&E and Masson staining; the Gene ontology (GO) analysis the transcriptional profiling changes; the mitochondrial ATP generation, mitochondrial redox status, mitochondrial DNA (mtDNA) N6-methyladenine (6mA) level and relative mtDNA genes expressions were examined. In addition, immunofluorescence detect the cell localization of 6mA in human pancreatic cancer PANC1 cell. Using the TCGA database, the prognostic effect of mtDNA 6mA demethylation ALKBH1 expression on pancreatic cancer patients was analyzed.

Results: We confirmed the mtDNA 6mA levels were gradually increased with the mitochondrial dysfunction in PanINs progression. XCHT showed the effect to inhibit the occurrence and development of pancreatic cancer in Syrian hamster pancreatic tumorigenesis model. In addition, the lack of ALKBH1 mediated mtDNA 6mA increase, mtDNA coded genes down-expression and abnormal redox status were rescued by XCHT.

Conclusions: ALKBH1/mtDNA 6mA mediated mitochondrial dysfunction to induce the occurrence and progression of pancreatic cancer. XCHT can improve ALKBH1 expression and mtDNA 6mA level, regulate the oxidative stress and expression of mtDNA coded genes. This study investigated a new molecular mechanism of pancreatic tumorigenesis, and revealed the therapeutic efficacy of XCHT in pancreatic tumorigenesis for the first time.

Keywords: ALKBH1; Mitochondrial dysfunction; N6-Methyladenine modification; Pancreatic tumorigenesis; Xiao Chai Hu Tang; mtDNA.