Downregulation of ASF1B inhibits tumor progression and enhances efficacy of cisplatin in pancreatic cancer.

Abstract

Pancreatic cancer is an aggressive and lethal cancer with the highest mortality rate. Hence, the development of new targeting and innovative treatment strategies is needed. Recent studies reported that the histone chaperone anti-silencing function 1B (ASF1B) can be used as a diagnosis and prognosis cancer biomarker. However, functional studies of ASF1B in pancreatic cancer have not been performed. This study compared expression levels of ASF1B in pancreatic cancer specimens with those of normal tissues using publicly available online databases. We found that ASF1B was commonly overexpressed in pancreatic cancer specimens, which is associated with poor prognosis. ASF1B downregulation in pancreatic cancer cells reduced their colony formation, proliferation, migration, and invasion abilities, and inhibited MMP9 activity. Furthermore, ASF1B expression downregulation increased cell cycle S-phase arrest and DNA damage though activation of the checkpoint kinases Chk1 and Chk2 pathways. Additionally, increased caspase (caspases-3 and -9) activation and PARP cleavage led to enhanced caspase-dependent apoptosis and improved cisplatin sensitivity. Collectively, our results indicate that ASF1B may serve as a potential biomarker of pancreatic cancer and a novel therapeutic target.