Downregulation of inhibitor of apoptosis‑stimulating protein of p53 inhibits proliferation and promotes apoptosis of gastric cancer cells.

Gastric cancer (GC) remains one of the leading causes of cancer-associated mortality. Inhibitor of apoptosis-stimulating protein of p53 (iASPP) is a member of the inhibitory apoptosis-stimulating protein p53 family. The overexpression of iASPP has been detected in several types of tumor in humans. However, the role of iASPP in GC remains to be elucidated. The objectives of the present study were to detect the expression of iASPP in GC and examine the potential role of iASPP in GC cell lines. Using reverse transcription-quantitative polymerase chain reaction and western blot analyses, it was identified that the expression of iASPP in GC tissues and GC cell lines was higher compared with that in adjacent normal tissues and in a normal gastric mucosa cell line (GES-1). To examine the role of iASPP in GC cells, the expression of iASPP was inhibited using a small interfering (si)RNA against iASPP and it was observed that iASPP expression was significantly downregulated. Using MTT assays, colony-formation assays and flow cytometry, it was identified that the inhibition of iASPP was able to significantly inhibit the proliferation and colony forming ability and promote apoptosis in GC cells. To examine the role of iASPP in GC cells in vivo, GC cells, which were infected with iASPP-siRNA or control-siRNA were subcutaneously injected into nude mice. It was identified that downregulation of iASPP significantly inhibited tumor growth in vivo. Thus, iASPP may be a potential molecular target in GC therapy.