Correlations of the expression of Cx43, SCFFBXW7, p-cyclin E1 (Ser73), p-cyclin E1 (Thr77) and p-cyclin E1 (Thr395) in colon cancer tissues.

Abstract

Background: Previous cellular studies have demonstrated that elevated expression of Cx43 promotes the degradation of cyclin E1 and inhibits cell proliferation through ubiquitination. Conversely, reduced expression results in a loss of this capacity to facilitate cyclin E degradation. The ubiquitination and degradation of cyclin E1 may be associated with phosphorylation at specific sites on the protein, with Cx43 potentially enhancing this process by facilitating the phosphorylation of these critical residues.

Aim: To investigate the correlation between expression of Cx43, SKP1/Cullin1/F-box (SCF)^FBXW7, p-cyclin E1 (ser73, thr77, thr395) and clinicopathological indexes in colon cancer.

Methods: Expression levels of Cx43, SCF^FBXW7, p-cyclin E1 (ser73, thr77, thr395) in 38 clinical colon cancer samples were detected by immunohistochemistry and were analyzed by statistical methods to discuss their correlations.

Results: Positive rate of Cx43, SCF^FBXW7, p-cyclin E1(Ser73), p-cyclin E1 (Thr77) and p-cyclin E1 (Thr395) in detected samples were 76.32%, 76.32%, 65.79%, 5.26% and 55.26% respectively. Positive expressions of these proteins were not related to the tissue type, degree of tissue differentiation or lymph node metastasis. Cx43 and SCF^FBXW7(r = 0.749), p-cyclin E1 (Ser73) (r = 0.667) and p-cyclin E1 (Thr395) (r = 0.457), SCF^FBXW7 and p-cyclin E1 (Ser73) (r = 0.703) and p-cyclin E1 (Thr395) (0.415) were correlated in colon cancer (P < 0.05), and expressions of the above proteins were positively correlated in colon cancer.

Conclusion: Cx43 may facilitate the phosphorylation of cyclin E1 at the Ser73 and Thr195 sites through its interaction with SCF^FBXW7, thereby influencing the ubiquitination and degradation of cyclin E1.