RT-PCR (Figure 5A) and immunoblot (Figure 5B) analyses of HT29 cells revealed Bak expression was markedly increased in adherent and non-adherent carcinoma cells expressing CXCL12 relative to the transfection control GFP cells.
Graber [ 22] explained the increase of Bak expression in tumor tissues where the tumor cells and the stroma cells expressed only low levels of Bak.
Incubation of cells with antibody reduced levels of anti-apoptotic Bcl-2, while elevating pro-apoptotic BAD, BAX and BAK expression as well as cleaved caspases-3, -7, -8 and -9.
BAK expression has been reported in normal gastrointestinal epithelium [ 8].
In contrast in cells containing mutant p53 (e.g. DLD1), Bak expression was remarkably increased.
Loss of both Bax or Bak expression has been reported for a number of tumors.
Western blot analysis confirmed the lack of Bak expression in cancer cells.
In contrast, CDDP-treatment of pxn65 tumours did not significantly alter BAX and BAK expression.
First, the mean of the Bak expression in normal tissues was 0.350.
On the other hand, Bak expression varied more than fivefold among these cells.
There was no significant correlation between Bak expression and invasive carcinoma.
