Expression of caveolin-1 is correlated with Akt-1 in colorectal cancer tissues

Caveolin is a major component of caveolae which is a plasma membrane microdomain. The emerging role of caveolin in tumorigenesis was based mainly on in vitro experiments with cancer cell lines. We performed semi-quantitative RT-PCR for caveolin, Akt and EGFR to understand the role of caveolins in colorectal tumor biology. Cancer tissue samples and the neighboring normal colon mucosa were obtained from 95 colorectal cancer patients who underwent operations at Ewha Womans University Mokdong Hospital. With these fresh tissues, semi-quantitative RT-PCR was performed by coamplification of the gene for caveolin-1, EGFR and Akt-1 with beta-actin. The average age was 60.21+/-13.33 years old, and sex ratio was 1.44:1. Caveolin-1 is more expressed in tumors than normal mucosa (P=0.025). The expression of caveolin-1 and Akt-1 had a definitive positive relationship (P=0.002). But, the expression of caveolin-1 and EGFR was not significantly related. We could not find correlations between caveolin-1 expression and clinical factors. In conclusion, caveolin-1 is more expressed in cancer tissues than normal colon and related with Akt-1, not with EGFR expression in colorectal cancer tissues, which suggests that signaling for caveolin-1 affects Akt-1 activation, but this reaction is not initiated by EGFR stimulation in colon cancer.