Expression of KITENIN in human colorectal cancer and its relation to tumor behavior and progression.

KAI1 COOH-terminal interacting tetraspanin (KITENIN) contributes to tumor invasion and metastasis in various cancers. The aim of current study was to evaluate whether KITENIN affects tumor cell invasion and prognosis in human colorectal cancers. We investigated the biologic role of KITENIN on tumor cell invasion by using small interfering RNA in Caco2, DLD1, and SW480. We evaluated the expression of KITENIN and activator protein-1 (AP-1) target genes in human colorectal cancer tissues. The tumor cell invasion was decreased by knockdown of KITENIN in three tested cell lines. The mRNA expression of cyclin D1 and COX-2 was decreased in KITENIN knockdown Caco2 and the mRNA expression of MMP-3 and COX-2 was decreased in KITENIN knockdown DLD1 and SW480. The extracellular-signal protein kinase 1/2 (ERK1/2) phosphorylation was decreased in KITENIN knockdown in three tested cell lines. Expression of KITENIN and AP-1 target genes was significantly increased in human colorectal cancer tissues. The ERK1/2, c-Jun N-terminal kinase (JNK) and p38 phosphorylations were increased in human colorectal cancer tissues. Expression of KITENIN was significantly associated with lymphovascular invasion, depth of invasion, lymph node metastasis, tumor stage and poor survival. These results indicate that KITENIN is associated with human colorectal cancer progression including invasion and metastasis.