ECRG1, a novel esophageal gene, cloned and identified from human esophagus and its inhibition effect on tumors

ECRG-1 (esophageal cancer-related gene 1) has been previously found to be down-regulated in human esophagus cancer. Transient expression of green fluorescent protein (GFP)-tagged ECRG1 showed plasma membrane localization. Treatment of esophagus cancer cell line (NEC) with ECRG-1 fusion protein and over-expression of ECRG-1 in NEC cells can significantly reduce the in vitro proliferation rate of NEC cells. Treatment of established NEC tumors in the nude mice with ECRG-1 fusion protein leads to decreased tumor weight and volume. Over-expression of ECRG-1 in NEC cells can also inhibit tumor formation in nude mice. Cell-cycle analysis showed that over-expression of ECRG-1 in NEC cells results in G₂/M phase arrest. Our findings indicate that ECRG1 may be a candidate tumor suppressor gene for esophageal cancer (EC) involved in cell-cycle control. Since ECRG-1 gene significantly suppresses the growth of NEC cells both in vitro and in vivo, its loss may contribute to the causation and progression of the EC in Lin-xian county, which is a high incidence area of EC in China.