The chromosome 2 open reading frame 40 (C2ORF40) gene is a candidate tumor suppressor gene for a variety of
tumors. Previous results by the present authors revealed that the C2ORF40
protein is a secreted
protein. However, the exact biological function of secreted C2ORF40
protein in
carcinogenesis has not been thoroughly investigated. In the present study, the
signal peptide sequence of the C2ORF40
cDNA was initially removed to produce secreted recombinant human C2ORF40
protein (rhC2ORF40). Soluble rhC2ORF40 was successfully expressed and purified, which was evaluated for the first time, to the best of our knowledge, for
tumor-suppressing function in vivo in
esophageal cancer. The present results revealed that soluble purified rhC2ORF40 was concentrated with a purity of >95%. Furthermore, rhC2ORF40 inhibited
esophageal cancer cell growth in vivo in a dose-dependent manner compared with a control group (P<0.05). In addition, the present study demonstrated for the first time that rhC2ORF40 decreased
telomerase activity using telomeric repeat amplification protocol-
enzyme-linked
immunosorbent assay (P<0.05), without affecting the expression levels of
telomerase-component
RNA (P>0.05), as shown with polymerase chain reaction. Overall, the present results demonstrated that soluble rhC2ORF40 inhibited
tumor cell growth in vivo by decreasing
telomerase activity in
esophageal squamous cell carcinoma. Therefore, soluble rhC2ORF40 with a high purity and biological activity may be a potential
biological therapy drug for
esophageal cancer.