Andrographolide suppresses the malignancy of pancreatic cancer via alleviating DNMT3B-dependent repression of tumor suppressor gene ZNF382.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive cancer type that urgently requires effective therapeutic strategies. Andrographolide, a labdane diterpenoid compound abundant in Andrographis paniculata, has anticancer effects against various cancer types, but its anticancer activity and mechanism against PDAC remain largely uncharacterized. PURPOSE: This study explores novel drug target(s) and underlying molecular mechanism of andrographolide against PDAC. STUDY DESIGN AND METHODS: The malignant phenotypes of PDAC cells, PANC-1 and MIA PaCa-2 cells, were measured using MTT, clonogenic assays, and Transwell migration assays. A PDAC xenograft animal model was used to evaluate tumor growth in vivo. Western blot, immunofluorescence and immunohistochemistry were used for measuring protein expression. The TCGA database was analyzed to evaluate promoter methylation status, gene expression, and their relationship with patient survival rates. RT-qPCR was used for detecting mRNA expression. Reporter assays were used for detecting signal transduction pathways. Promoter DNA methylation was determined by sodium bisulfite treatment and methylation-specific PCR (MSP). The biological function and role of specific genes involved in drug effects were measured through gene overexpression. RESULTS: Andrographolide treatment suppressed the proliferation and migration of PDAC cells and impaired tumor growth in vivo. Furthermore, andrographolide induced the mRNA and protein expression of zinc finger protein 382 (ZNF382) in PDAC cells. Overexpression of ZNF382 inhibited malignant phenotypes and cancer-associated signaling pathways (AP-1, NF-κB and ß-catenin) and oncogenes (ZEB-1, STAT-3, STAT-5, and HIF-1α). Overexpression of ZNF382 delayed growth of PANC-1 cells in vivo. ZNF382 mRNA and protein expression was lower in tumor tissues than in adjacent normal tissues of pancreatic cancer patients. Analysis of the TCGA database found the ZNF382 promoter is hypermethylated in primary pancreatic tumors which correlates with its low expression. Furthermore, andrographolide inhibited the expression of DNA methyltransferase 3 beta (DNMT3B) and increased the demethylation of the ZNF382 promoter in PDAC cells. Overexpression of DNMT3B attenuated the andrographolide-suppressed proliferation and migration of PDAC cells. CONCLUSION: Our finding revealed that ZNF382 acts as a tumor suppressor gene in pancreatic cancer and andrographolide restores ZNF382 expression to suppress pancreatic cancer, providing a novel molecular target and a promising therapeutic approach for treating pancreatic cancer.

Carbon monoxide­releasing molecules protect against blue light exposure and inflammation in retinal pigment epithelial cells.

The most common cause of vision loss among the elderly is age­related macular degeneration (AMD). The aim of the present study was to investigate the potential cytoprotective and anti­inflammatory effects of carbon monoxide­releasing molecules (CORMs), and their ability to activate the expression of nuclear factor erythroid 2­related factor 2 (Nrf2)­related genes in human retinal pigment epithelium (RPE) cells, as well as the inhibition of endothelial cell migration. It was first determined that CORM2 and CORM3 suppressed blue light­induced cell damage. In addition, a decrease in the level of cleaved poly(ADP­ribose) polymerase 1 protein and dissipation of mitochondrial membrane potential were considered to reflect the anti­apoptotic activity of CORMs. Furthermore, CORM2 induced Nrf­2 activation and the expression of the Nrf2­related genes heme oxygenase­1 and glutamate­cysteine ligase. Pretreatment with CORM2 abolished the blue light­induced increase in oxidative stress, suggesting that CORM2­induced antioxidant activity was involved in the cytoprotection against blue light. It was also demonstrated that CORMs markedly suppressed tumor necrosis factor (TNF)α­induced intercellular adhesion molecule­1 expression. Moreover, it was further observed that CORMs exert their inhibitory effects through blocking nuclear factor­κB/p65 nuclear translocation and IκBα degradation in TNFα­treated RPE cells. It was observed that CORM2, but not CORM3, protected against oxidative stress­induced cell damage. CORMs abolished vascular endothelial growth factor­induced migration of endothelial cells. The findings of the present study demonstrated the cytoprotective, antioxidant and anti­inflammatory effects of CORMs on RPE cells and anti­angiogenic effects on endothelial cells, suggesting the potential clinical application of CORMs as anti­AMD agents.