[The expression and clinical significance of SphK1 and nuclear factor-κB p65 in human colon carcinoma]

Abstract

Objective: To investigate the expression of sphingosine kinase 1 (SphK1) and NF-κB in colon carcinoma tissues and their correlation with clinicopathologic features.

Methods: Sixty-six paraffin-embedded colon carcinoma samples and 66 fresh colon carcinoma samples were tested using immunohistochemistry, RT-PCR and Western blot, respectively.

Results: In 66 fresh colon carcinoma samples, the positive rate of SphK1 and NF-κB mRNA expression were 84.85%(56/66) and 74.24% (49/66), while the positive rate of SphK1 and NF-κB protein detected by Western blot were 78.79% (52/66) and 69.70% (46/66). The positive rates were higher than those in the adjacent tissues [mRNA: 63.64% (42/66), 48.49% (32/66); protein: 57.58% (38/66), 45.45% (30/66)] and the normal mucosa [mRNA: 42.42% (28/66), 25.76% (17/66); protein: 36.36% (24/66), 24.24% (16/66)], with statistical significances (all P values < 0.05). The mean expressive levels of SphK1 and NF-κB mRNA and protein in colon carcinoma were both significantly higher than those in the adjacent tissues and the normal mucosa (mRNA: 0.55 ± 0.06 vs 0.35 ± 0.05 vs 0.25 ± 0.05, 0.75 ± 0.06 vs 0.43 ± 0.05 vs 0.30 ± 0.04; protein: 0.77 ± 0.05 vs 0.38 ± 0.06 vs 0.12 ± 0.03, 0.45 ± 0.08 vs 0.23 ± 0.05 vs 0.13 ± 0.03; all P values < 0.05). There was a close correlation between SphK1 and NF-κB expression levels (r = 0.459, P = 0.036). The results of immunohistochemistry were similar to those of RT-PCR and Western blot. Overexpression of SphK1 and NF-κB in colon carcinoma was related with depth of invasion, distant and lymph node metastasis and Dukes' stages (all P values < 0.05). The expression of SphK1 was also related with differentiation (P < 0.05).

Conclusions: Overexpression of SphK1 and NF-κB may be involved in the pathogenesis and progression of colon carcinoma. Moreover, SphK1 and NF-κB may be correlated with the invasion and metastasis of colon carcinoma.