OBJECTIVETo compare the expressions of hypoxia-inducible factor 1 alpha(HIF-1α) and Semaphorin 4D(Sema4D) in colorectal carcinoma and normal colorectal tissues, and to investigate their correlation and clinical significance.

METHODSThe expressions of HIF-1α and Sema4D were examined in 86 cases of colorectal carcinoma and 52 normal colorectal tissues by SP immunohistochemical staining. Correlation between these two expressions and association of the expressions with clinicopathological characters and prognosis were analyzed.

RESULTSThe positive rates of HIF-1α and Sema4D protein in colorectal carcinoma tissues were significantly higher than those in normal colorectal tissues(58.1% vs. 7.7%, χ(2)=34.624, P<0.01; 60.5% vs. 11.5%, χ(2)=31.839, P<0.01). HIF-1α and Sema4D protein expressions were closely associated with colorectal carcinoma histological types(P=0.003, P=0.010), TNM staging (P=0.003, P=0.017) and lymphatic metastasis (P=0.003, P=0.020), and a significant correlation was observed between the expressions of HIF-1α and Sema4D protein (r=0.567, P<0.01). The 5-year overall survival rate was 37%. Univariate analysis showed that 5-year survival rates of patients with positive and negative HIF-1α protein expression were 24% and 56%(P=0.003), and those with positive and negative Sema4D protein expression were 23% and 59%(P=0.001). Multivariate Cox analysis showed that expression of Sema4D was an independent prognostic factor of colorectal cancer patients(P=0.026), while expression of HIF-1α was not(P=0.501).

CONCLUSIONCombined detection of HIF-1α and Sema4D has the potential to predict the development trend of colorectal carcinoma and prognosis of patients.

Antigens, CD ; metabolism ; Colorectal Neoplasms ; metabolism ; Humans ; Hypoxia-Inducible Factor 1, alpha Subunit ; metabolism ; Lymphatic Metastasis ; Neoplasm Staging ; Prognosis ; Semaphorins ; metabolism ; Survival Rate

BACKGROUNDHypoxia promotes tumor angiogenesis and hypoxia-inducible factor-1 alpha (HIF-1α) plays a pivotal role in this process. Recently identified pro-angiogenic factor, semaphorin4D (Sema4D) also promotes angiogenesis and enhances invasive proliferation in some tumors. Furthermore, tumor-associated macrophages (TAMs) can increase the expression of HIF-1α and Sema4D in cancer cells and thus influence tumor growth and progression. The purpose of this study was to evaluate the effect of TAMs on the expression of Sema4D and HIF-1α and the impact of biologic behavior in colon cancer cells.

METHODSImmunohistochemistry was used to analyze HIF-1α and Sema4D expression in 86 curatively resected colon cancer samples and 52 normal colon tissues samples. The relationship between their expression and clinicopathological factors was analyzed. Furthermore, macrophage-tumor cell interactions, such as metastasis, angiogenesis, were also studied using in vitro co-culture systems. Statistical analysis was performed using SPSS 17.0 software (SPSS Inc., USA). Differences between two groups were analyzed with Student's t test.

RESULTSHIF-1α (58%) and Sema4D (60%) were expressed at a significantly higher level in tumors than in normal tissues (P < 0.01, for both). Furthermore, HIF-1α and Sema4D expression was significantly correlated with lymphatic metastasis, specific histological types and TNM stages (P < 0.05), but not with age and tumor size (P > 0.05). Sema4D expression was correlated with that of HIF-1α (r = 0.567, P < 0.01). TAMs markedly induced HIF-1α and Sema4D expression in colon cancer cells and subsequently increased their migration and invasion.

CONCLUSIONSHIF-1α and Sema4D expression are closely related to lymphatic metastasis, specific histological types and TNM stages in colon cancer. Furthermore, TAMs promote migration and invasion of colon cancer cells and endothelial tube formation, possibly through up-regulation of HIF-1α and Sema4D.

Adult ; Aged ; Antigens, CD ; genetics ; metabolism ; Cell Line, Tumor ; Colonic Neoplasms ; genetics ; metabolism ; Female ; Humans ; Hypoxia-Inducible Factor 1, alpha Subunit ; genetics ; metabolism ; Immunohistochemistry ; Macrophages ; immunology ; metabolism ; Male ; Middle Aged ; Neoplasm Metastasis ; genetics ; pathology ; Semaphorins ; genetics ; metabolism