Apatinib affects the proliferation, migration and apoptosis of esophageal cancer cells both in vitro and in xenografts by regulating Ras/Raf/MEK/ERK and JAK2/STAT3 signaling pathways.

Abstract

e15501 Background: To investigate the effects of apatinib on esophageal cancer cells in vitro and xenograft models, and discuss the mechanisms of its actions. Methods: Used various assays to measure the different biological processes of esophageal cancer cells: used MTT assay to measure the proliferation rate; used transwell assay to determine the migration capacity and used colony formation assay to assess the clone formation rate. The effect of apatinib on cell cycle and apoptosis was analyzed by flow cytometry. The expression levels of VEGF and VEGFR2 were measured by qRT-PCR. The concentration of VEGF in the supernatant of cancer cell was assessed by ELISA. The expression levels of MEK, ERK, p-MEK, p-ERK, STAT3, p-STAT3, CHK2 and CDC2 after VEGF stimulation were detected by western blot. We also established human esophageal squamous carcinoma xenograft model in nude mice. The mice were randomly divided into healthy control group, low dose group (250mg) and high dose group (500mg), with 6 mice in each group. The tumor growth rate of each group was calculated, and the expression levels of VEGF and VEGFR2 in tumor tissues were detected by immunohistochemistry. Results: Apatinib inhibited the proliferation of esophageal cancer cell in a time-dependent (P < 0.05) and concentration-dependent (P < 0.05) manner; it also inhibited the cell migration capacity (P < 0.05) and colony formation rate (P < 0. 05). In addition, apatinib induced apoptosis in esophageal cancer cells and increased the proportion of cells in G2 / M phase (P < 0.05). The mRNA levels of VEGF (P < 0.05) and VEGFR2 (P < 0.05) and the protein levels of VEGF (P < 0.05) were also suppressed by apatinib. Western blot showed that apatinib could down-regulate the expression of p-MEK, p-ERK, STAT3, p-STAT3, CHK2 and CDC2 (P < 0.05). The inhibition rates of apatinib in esophageal carcinoma xenograft model was 29.25% and 19.96% for 250mg and 500mg drug treatment groups. Compared with healthy control group, the VEGF levels in drug treatment groups were not significantly different (P > 0.05), but the VEGFR2 levels were significantly decreased (P < 0.05). Conclusions: Apatinib can induce apoptosis of esophageal cancer cell KYSE-150 and ECA-109, and inhibit the cell proliferation, migration and colony formation. Moreover, apatinib can inhibit the tumor growth in esophageal carcinoma xenograft models. This inhibitory action of apatinib is related to the alterations in VEGF-related pathways such as Ras / Raf / MEK / ERK and JAK2 / STAT3 pathways.