Effects of inhibition of PIK3CA signaling on the expression of PIK3R3. HGC27 and IM95 GC cells were seeded in complete medium overnight. The complete medium was replaced by serum free medium, and PIK3CA inhibitor LY294002 was added. Total RNA or cell lysates were harvested 24 h after treatment. The relative PIK3R3 mRNA level (A) or protein level (B) was measured by quantitative RT-PCR or western blot.