The regulatory role of SLP-2 and mechanism on CCBE1 gene expression in rectal carcinoma and adjacent lymphatic tube tissues.

Abstract

The incidence of rectal carcinoma (RC) has been increasing recently, and becomes the second most common digestive tumors besides gastric cancer, with a rise in the incidence of RC in younger populations. The early diagnosis and treatment are thus critical for the improvement of survival rate and life quality of patients. Stomatin-like protein 2 (SLP-2) is a type of membrane factor, which is generally found highly expressed in various tumors. Collagen and calcium-binding EGF domain (CCBE1) belongs to lymphatic tube genesis factor. The regulatory role of SLP-2 gene on CCBE1 expression in RC tumor and adjacent lymphatic tube tissues, however, has not been studied. 52 RC patients were recruited, and tumor and adjacent lymphatic tube tissues were collected. Real-time PCR, western blotting and immunohistochemistry (IHC) staining were used to analyze SLP-2 and CCBE1 expressions. Human lymphatic endothelial cells (LECs) were cultured in vitro and were assigned to control, scramble, and SLP-2 siRNA group. MTT assay was used to detect cell proliferation, while caspase 3 activity was detected. SLP-2 and CCBE1 levels were significantly elevated in tumor lymphatic tissues, compared to that in adjacent tissues. Statistically positive correlation between SLP-1 and CCBE2 was found (p<0.05). The downregulation of SLP-2 by siRNA inhibited cell proliferation, elevated caspase3 activity, and decreased CCBE1 expression (p<0.05 compared to control group). SLP-2 is up-regulated in RC lymphatic tissues, and is positively correlated with the level of CCBE1, which provides the academic the basis for the development of medicine targeting SLP-2 in the anti-rectal carcinoma therapy.