Design, synthesis and investigation of procaine based new Pd complexes as DNA methyltransferase inhibitor on gastric cancer cells

Epigenetic signatures in gastric cancer: current knowledge and future perspectives

INTRODUCTION

Gastric cancer (GC) is the fifth most common malignancy in the world and accounts for 7.7% of all cancer-related deaths. Early diagnosis of GC is critical in terms of prognosis, and aberrations at the molecular level, especially epigenetic alterations, manifest much earlier than histological findings. In recent years, there has been a great deal of research on the epigenomic profile of GC, and epigenetic alterations seem to play a more important role than genetic factors. With the introduction of epigenetic drugs into clinical use in the last decade, the importance of the epigenetic background of GC has increased considerably.

AREAS COVERED

In this review, we summarize the role of methylation changes, histone modifications, and non-coding RNAs in the pathogenesis of GC and how these signatures can be used as diagnostic and therapeutic targets in clinical management.

EXPERT OPINION

Epigenetic alterations take place before most genetic aberrations observed in GC and may have an initiating role in the pathogenesis of GC. They can be used as biomarkers in risk calculation, early diagnosis, and evaluation of prognosis of GC, as well as treatment targets.

PAX9 reactivation by inhibiting DNA methyltransferase triggers antitumor effect in oral squamous cell carcinoma

Aberrant DNA hypermethylation is associated with oral carcinogenesis. Procaine, a local anesthetic, is a DNA methyltransferase (DNMT) inhibitor that activates anticancer mechanisms. However, its effect on silenced tumor suppressor gene (TSG) activation and its biological role in oral squamous cell carcinoma (OSCC) remain unknown. Here, we report procaine inhibited DNA methylation by suppressing DNMT activity and increased the expression of PAX9, a differentiation gene in OSCC cells. Interestingly, the reactivation of PAX9 by procaine found to inhibit cell growth and trigger apoptosis in OSCC in vitro and in vivo. Likely, the enhanced PAX9 expression after exposure to procaine controls stemness and differentiation through the autophagy-dependent pathway in OSCC cells. PAX9 inhibition abrogated procaine-induced apoptosis, autophagy, and inhibition of stemness. In OSCC cells, procaine improved anticancer drug sensitivity through PAX9, and its deficiency significantly blunted the anticancer drug sensitivity mediated by procaine. Additionally, NRF2 activation by procaine facilitated the antitumor response of PAX9, and pharmacological inhibition of NRF2 by ML385 reduced death and prevented the decrease in the orosphere-forming potential of OSCC cells. Furthermore, procaine promoted antitumor activity in FaDu xenografts in athymic nude mice, and immunohistochemistry data showed that PAX9 expression was significantly enhanced in the procaine group compared to the vehicle control. In conclusion, PAX9 reactivation in response to DNMT inhibition could trigger a potent antitumor mechanism to provide a new therapeutic strategy for OSCC.