RT-PCR identification of differential gene expression induced by latexin expression in gastric cancer cells. To validate the results of Microarray analysis, 9 differentially expressed genes in MGC803 cells in response to latexin expression were subjected to RT-PCR analysis. (A) MGC803 cells stably overexpressing latexin (C39-8 and C46) and control MGC803 cells transfected with empty vector were used for analysis. Lane 1 represents negative control using isolated cellular RNA as PCR template. Lanes 2, 3, and 4 represent amplification using reverse transcripts derived from control MGC803 cells, C39-8, and C46 cells, respectively. (B) The expression of these identified genes was also analyzed in latexin knockdown BGC823 cells, C3 and C7. Lane 1 represents negative control. Lanes 2, 3, and 4 represent amplification results of control BGC803 cells, C3, and C7 cells, separately. For each target gene tested, N and N+2 cycles of RT-PCR amplification were performed to ensure that the PCR reactions fall within the linear range of amplification. The number of cycling (N) for each target gene was shown in Table 1. β-actin was used as the internal control.