Efficacy of HMJ-38, a new quinazolinone analogue, against the gemcitabine-resistant MIA-PaCa-2 pancreatic cancer cells

Gemcitabine is frequently utilized to treat pancreatic cancer. The purpose of our study was to create a gemcitabine-resistant MIA-PaCa-2 pancreatic cancer cell line (MIA-GR100) and to evaluate the anti-pancreatic cancer efficacy of HMJ-38, a new quinazolinone analogue. Compared to their parental counterparts, MIA-PaCa-2, established MIA-GR100 cells were less sensitive to gemcitabine. MIA-GR100 cell viability was not affected by 10, 50 and 100 nM gemcitabine concentrations. HMJ-38 reduced MIA-GR100 cell growth and induced autophagy and apoptosis. When stained with monodansylcadaverine (MDC), acridine orange (AO), and terminal deoxynucleotide transferase dUTP nick end labeling (TUNEL), MIA-GR100 cells shrunk, punctured their membranes, and produced autophagy vacuoles and apoptotic bodies. Combining chloroquine (CQ) and 3-methyladenine (3-MA) with HMJ-38 dramatically reduced cell viability, indicating that autophagy function as a cytoprotective mechanism. MIA-GR100 cells treated with both z-VAD-FMK and HMJ-38 were much more viable than those treated with HMJ-38 alone. HMJ-38 promotes apoptosis in MIA-GR100 cells by activating caspases. Epidermal growth factor receptor (EGFR) is one of HMJ-38's principal targets, as determined via in silico target screening with network prediction. HMJ-38 also inhibited EGFR kinase activity and EGFR-associated signaling in MIA-GR100 cells. HMJ-38 may be an effective chemotherapeutic adjuvant for gemcitabine-resistant pancreatic cancer cells, in which it induces an antitumor response.

Effect of DNA damage response by quinazolinone analogue HMJ-38 on human umbilical vein endothelial cells: evidence for γH2A.X and DNA-PK-dependent pathway

The present study aims to explore the mechanism of quinazolinone analogue HMJ-38-induced DNA damage in endothelial cells in vitro. We attempt to evaluate the antiangiogenetic response utilizing human umbilical vein endothelial cells (HUVECs). Herein, the results demonstrated that HMJ-38 incubation triggered DNA damage behavior and showed a longer DNA migration in HUVECs based on the comet assay and the analysis of DNA agarose gel electrophoresis to contact DNA smears. We further gained to determine a marker of DNA double strand breaks, phosphorylated histone H2A.X (Ser139) (γH2A.X), in HMJ-38-treated HUVECs by flow cytometry and Western blotting assay. We consider that HMJ-38 has caused an increase in γH2A.X, and DNA damage seemed to mediate through DNA-dependent serine/threonine protein kinase (DNA-PK) binding to Ku70/Ku80 as well as advanced activated p-Akt (Ser473) and stimulated phosphorylated glycogen synthase kinase-3β (p-GSK-3β) conditions in HUVECs. Importantly, the effect of above DNA damage response was prevented by N-acetyl-l-cysteine (a reactive oxygen species scavenger), and NU7026 (a DNA-PK inhibitor) could attenuate DNA-PK catalytic subunit and phosphorylation of H2A.X on Ser139 expression in comparison with HMJ-38 alone treated HUVECs. Therefore, HMJ-38-provoked DNA damage stress in HUVECs probably led to the activation of γH2A.X/DNA-PK/GSK-3β signaling. In summary, our novel finding provides more information addressing the pharmacological approach of newly synthesized HMJ-38 for further development and therapeutic application in antiangiogenetic effect of cancer chemotherapy.