The Antipsychotic Agent Sertindole Exhibited Antiproliferative Activities by Inhibiting the STAT3 Signaling Pathway in Human Gastric Cancer Cells

Abstract

Gastric cancer (GC) is the third leading cause of cancer-related death. Although the therapeutic approaches have improved, the 5-year survival rate of GC patients after surgical resection remains low due to the high rates of metastasis and recurrence. Patients with schizophrenia have significantly lower incidences of cancer after long-term drug treatment, suggesting the potential or partially ameliorate the risk of cancer development of antipsychotic drugs. The goal of this study was to explore antipsychotic drugs with an optional effective therapy against gastric cellular carcinoma. We found that sertindole, an atypical antipsychotic, exhibited anti-tumor efficacy on human GC cells in vitro and in vivo. Moreover, sertindole in combination with cisplatin dramatically enhanced apoptosis-induction in GC cells. In addition, the pro-apoptotic effect of sertindole on GC might in part, involved in inhibition of STAT3 activation and downstream signals, including Mcl1, surviving, c-Myc, cyclin D1. Collectively, these results suggested that sertindole could be a potential anticancer reagent and be an attractive therapeutic adjuvant for the treatment of human GC.

Keywords: cell apoptosis; cisplatin; gastric cancer; sertindole.

Figure 1

Chemical structure of sertindole.

Figure 2

Sertindole inhibited gastric cancer (GC) cell proliferation in vitro. The growth inhibitory effect of sertindole was measured using the CCK-8 assay. Gastric cancer cell lines including HGC27, MGC803, BGC823 and MKN45 cells were treated with varying concentrations of sertindole (from 0 to 30 μM for 24 h). The experiments were performed in triplicate, and the data are presented as the mean ± standard deviation (SD) of three separate experiments.

Figure 3

Sertindole induced cell apoptosis in GC cells. (A) MGC803 and MKN45 cells were treated with gradient concentrations of sertindole for 24 h. Then, the cells were stained with PI at 37 °C for 30 min and measured by flow cytometry after collection. (B) Quantitative analysis of apoptotic cells. The percentage of cells in different phases of cell apoptosis was represented by a bar diagram. Data are presented as the mean ± SD of three independent experiments. (C) Effects of sertindole on the expression of apoptotic-associated proteins. (D) MGC803 and MKN45 GC cells were treated with 0, 5, 10 and 15 μM of sertindole for 24 h, and cell lysates were subjected to western blot analysis with cleaved PARP, caspase-3 and caspase-9 antibodies.

Figure 4

Sertindole suppressed GC cell proliferation through inhibition of JAK2-STAT3 signal pathway. (A) The GC cells were treated with sertindole at gradient concentrations for 8 h. The cell lysates were then separated by 12% SDS-PAGE electrophoresis, and the levels of proteins related to JAK-STAT3 signaling pathway were detected. (B) MGC803 and MKN45 cells was treated with 15 μM sertindole for 0, 0.5, 1, 2, 4 and 8 h, the levels of STAT3 and phosphorylated STAT3 (p-Stat3-y705) were detected by western blot analysis. (C) Western blot determined the levels of STAT3 downstream targets, including Mcl1, surviving, c-Myc, cyclin D1.

Figure 5

Combined treatment of sertindole and cisplatin to GC cells reduced cell viability. The effects of sertindole alone, cisplatin alone or sertindole together with cisplatin on cell viability were measured by cck8 assay. Combined treatment inhibited viability in MGC803 (A) and MKN45 (B) cell lines in a dose-dependent manner.

Figure 6

Sertindole potentiated the apoptotic-induction effects of cisplatin in GC cells. (A) The MKN45 and MGC803 cells were treated with sertindole alone, cisplatin alone or sertindole in combination with cisplatin for 24 h. The cells were collected and stained with PI at 37 °C for 30 min, then measured by flow cytometry. (B) The histogram of cell apoptosis rates. Data are presented as the mean ± SD of three independent experiments. (C) The MKN45 cells were treated with sertindole alone, cisplatin alone or sertindole in combination with cisplatin for 24 h. The cell lysates were then separated by 12% SDS-PAGE electrophoresis, and cell apoptotic- and growth-related proteins expressions were detected by western blot analysis.

Figure 7

Sertindole inhibited tumor growth of MGC803 cells in nude mice. (A) The transplanted tumors in nude mice; (B) The transplantation tumors removed from nude mice; (C) Tumor volumes were measured on the indicated days; (D) The weight of the transplanted tumor. **P<0.01 vs. control.