Erdr1 Suppresses Murine Melanoma Growth via Regulation of Apoptosis

Melanoma, one of the aggressive cancers, is known to be resistant to chemotherapy. Because of its aggressive nature, effectively inducing apoptosis is necessary to treat melanoma. Erythroid differentiation regulator 1 (Erdr1) is known to be a stress-related survival factor exhibiting anti-cancer effects in several cancers. However, little is known about the functions and underlying mechanisms of Erdr1 so far. To demonstrate the effect of Erdr1 in melanoma apoptosis, recombinant murine Erdr1 was injected into mice implanted with B16F10 melanoma cells. In vivo tumor growth was significantly inhibited in mice injected with Erdr1 compared to the control. In addition, the tumor from Erdr1-injected mice showed an increased level of apoptosis. Accordingly, apoptosis-regulating factors including anti-apoptotic marker Bcl-2 and pro-apoptotic marker Bax in the tumor tissues were examined. As expected, the decreased level of Bcl-2 and increased level of Bax were detected in tumors within the mice injected with Erdr1. Based on the in vivo study, the role of Erdr1 in tumor apoptosis was further tested by incubating it with cells of the murine melanoma cell line B16F10. Erdr1-induced apoptosis in B16F10 cells was observed. Additionally, Erdr1 downregulated STAT3 activity, inhibiting apoptosis via regulation of the Bcl-2 family. Overall, data demonstrate that Erdr1 induced murine melanoma apoptosis through the regulation of Bcl-2 and Bax. These findings suggest that Erdr1 is a novel regulator of apoptosis in melanoma.