The developmental regulator HAND1 inhibits gastric carcinogenesis through enhancing ER stress apoptosis targeting CHOP and BAK which is augmented by cisplatin.

Epigenetic disruption of tumor suppressor genes, particularly aberrant CpG methylation, plays a crucial role in gastric cancer (GC) pathogenesis. Through CpG methylome and expression profiling, a developmental transcription factor Hand-And-Neural-crest-Derivative-expressed 1 (HAND1), was identified methylated and downregulated in GC. However, its role and underlying mechanisms in GC progression are poorly understood. Here, we show that HAND1 was frequently downregulated in GC by promoter methylation, and significantly correlated with tumor progression and poor prognosis of GC patients. High expression of HAND1 in GC patients was associated with significantly higher 5-year overall survival rates. Ectopic expression of HAND1 inhibited GC cell growth and migration . HAND1 expression increased ROS levels and cytosolic Ca concentration, enhanced cisplatin-induced apoptosis through endoplasmic reticulum (ER) stress/mitochondria-mediated apoptosis. Knockdown of CHOP and BAK attenuated HAND1-induced cell apoptosis. Overexpression of CHOP increased BAK expression. HAND1 interacts with CHOP, also directly binds to CHOP and BAK promoters and positively regulates BAK transcription. Thus, the present study demonstrates that is a tumor suppressor gene methylated in GC, induces ER stress and apoptosis CHOP and BAK, which is augmented by cisplatin. Low HAND1 expression is an independent poor prognostic factor for GC. The tumor-specific methylation of promoter could be a candidate biomarker for GC.