Hint1 expression inhibits proliferation and promotes radiosensitivity of human SGC7901 gastric cancer cells.

Gastric cancer is a prevalent, malignant tumor that frequently escapes treatment. Histidine triad nucleotide-binding protein 1 (Hint1) is a haploinsufficient tumor suppressor gene which contributes to intercellular communication, helps to regulate cell proliferation and survival, and is frequently underexpressed in gastric cancer. To examine the involvement of Hint1 in gastric cancer, small interfering RNA was used to knock down Hint1 expression in the human gastric cancer cell line SGC-7901. The data revealed that Hint1 inhibited cell proliferation, reduced radiation-induced DNA damage repair and caused G1 phase arrest, which increased the radiosensitivity of gastric cancer cells. Further mechanistic studies revealed a novel function of Hint1, whereby it acted as a negative regulator of extracellular signal-regulated kinase. These results demonstrated the critical function of Hint1 in the biology of human gastric cancer. Acting as a tumor growth suppressor and a radiosensitive agent, this protein is a potential biomarker and may be an attractive target for specific therapeutic interventions against gastric cancer.