A. Overexpression of APIP in SNU-620 gastric cancer cells enhances cell proliferation (middle, n = 3) and promotes tumor growth (bottom, n = 5). Ev, pcDNA3 empty; APIP, pAPIP. Representative xenograft tumors of sacrificed mice (right). B. Downregulation of APIP expression in SNU-16 gastric cancer cells suppresses cell proliferation (middle, n = 3) and in vivo tumor growth (bottom, n = 5). shControl, pSUPER.neo; shAPIP #2 and #3, APIP shRNAs. C. Expression of shRNA-resistant APIP* rescues cell growth-inhibitory phenotype in SNU-16 APIP knockdown cells. SNU-16 control and APIP knockdown cells were transfected with pcDNA, pAPIP or pAPIP* (shRNA-resistant APIP) for 72 h. Cell growth rates (lower) and APIP protein levels (upper) were assessed. All data are represented as mean ± S.D. (n ≥ 3). Statistical significance is indicated as follows: *, P < 0.05; **, P < 0.01.