Radiosensitizion effect of stattic on the xenograft of ECA109 esophageal cancer cells in nude mice

Objective To investigate the radiosensitization effect of stattic on the xenograft of esophageal squamous cell carcinoma (ESCC) ECA109 cells in nude mouse and explore the underlying mechanisms. Methods Male nude mice inoculated subcutaneously with ECA109 cells were used to examine the radiosensitization effect of stattic in vivo. When average volume of tumors was about 150 mm3, mice were randomly divided into 4 groups: control group, 25 mg/kg stattic alone group, ionizing radiation (IR) (6 Gy) alone group, and 25 mg/kg stattic plus IR group. During the term of treatment, the volume of tumors was measured every 2 days. On 25 days after treatment, the mice were killed and the expressions of pSTAT3, STAT3, HIF-1α and VEGF in ECA109 xenografts were assessed by Western blot and immunohistochemistry analysis. Results The volume of tumor in nude mice was (705.1±75.5)mm3 in stattic plus IR group, which was significantly smaller than that in IR group (113.5±101.4)mm3 and stattic alone group(1 696.5±100.6)mm3 (t=4.35, 14.14, P<0.0). The inhibition rate was (66.1±3.2)% in stattic plus IR group. The expression levels of pSTAT3, HIF-1α and VEGF were obviously decreased in the stattic plus IR group compared with other groups (t=17.07, 5.05, 3.54, P<0.05). Conclusions Stattic play a radiosensitization role in the xenograft of esophageal carcinoma in nude mice probably by inhibiting the signaling pathways of pSTAT3, HIF-1α and VEGF. Key words: Stattic; ECA109 cells; Radiosensitization; STAT3; HIF-1α