Expression of P-aPKC-iota, E-cadherin, and beta-catenin related to invasion and metastasis in hepatocellular carcinoma.

OBJECTIVES: Atypical protein kinase C iota (aPKC-iota) and its associated intracellular molecules, E-cadherin and beta-catenin, are important for cell polarization in tumorigenesis and progression. Expression of aPKC-iota, P-aPKC-iota (activated aPKC-iota), E-cadherin, and beta-catenin in hepatocellular carcinoma (HCC) was measured, and correlation with clinicopathological characteristics of HCC was analyzed. METHODS: Paraffin-embedded tumor tissue was obtained from patients with HCC after resection without preoperative radiotherapy or chemotherapy. Gene expression was detected by polymerase chain reaction (PCR), and protein expression was detected by immunohistochemistry and Western blot analysis. Expressions of aPKC-iota, P-aPKC-iota, E-cadherin, and beta-catenin were analyzed with relation to the clinicopathological data. RESULTS: The gene and protein expression of aPKC-iota are obviously higher in HCC tissues than that in peritumoral tissues and normal tissues by semiquantitative PCR and immunohistochemistry methods. Accumulation of aPKC-iota in HCC cytoplasm and nucleolus inhibited the later formation of belt-like adherens junctions (AJs) and/or tight junctions (TJs) in cell-cell contact. E-cadherin was reduced and accumulation of cytoplasm beta-catenin was increased in HCC. The expression of aPKC-iota was closely related to pathological differentiation, tumor size, invasion, and metastasis of HCC. CONCLUSION: Accumulation of cytoplasm aPKC-iota may reflect pathological differentiation, invasion, and metastasis potential of HCC. In this regard, our study on HCC revealed the potential usefulness of aPKC-iota, E-cadherin, and beta-catenin as a prognostic marker, closely related to pathological differentiation, invasion, metastasis, and prognosis of HCC.

Significance and expression of atypical protein kinase C-iota in human hepatocellular carcinoma.

BACKGROUND AND OBJECTIVE: Previous studies have indicated that abnormal expression of atypical protein kinase C (aPKC-iota) plays a critical role in occurrence and progression of malignant tumor. This study analyzed the correlation of aPKC-iota with clinicopathology in hepatocarcinoma and Cyclin E and investigated molecular mechanisms of invasion and metastasis of hepatocellular carcinoma. MATERIALS AND METHODS: The expression of the aPKC-iota gene was examined by reverse transcription-polymerase chain reaction in 7 specimens of normal liver tissues and 43 of hepatoma and adjacent tissues. Expression of aPKC-iota and Cyclin E protein was detected using immunohistochemistry and Western blot. Finally, we analyzed the correlation of aPKC-iota with clinicopathologic characteristics and invasion of hepatoma. RESULTS: The expression value (0.844 +/- 0.315) of aPKC-iota gene is obviously higher in hepatoma than the value (0.530 +/- 0.217) in adjacent tissues and the value (0.372 +/- 0.130) in normal tissue (P = 0.009). The positive expression rate (58.1%) of aPKC-iota protein in hepatoma is remarkably higher than the rate (23.3%) of adjacent tissues. The expression of aPKC-iota has a positive correlation with the expression of Cyclin E, differentiation degree, and invasion of tumor (P < 0.05). CONCLUSIONS: Differentiation degree and invasion of hepatoma are related to the expression of aPKC-iota, which plays an important role in invasion and metastasis of hepatoma.

Correlation of aPKC-iota and E-cadherin expression with invasion and prognosis of cholangiocarcinoma.

BACKGROUND: The abnormal expression of atypical protein kinase C-iota (aPKC-iota) subtype and E-cadherin play important roles in tumor occurrence and progression. This study was designed to investigate the correlation of expression of aPKC-iota and E-cadherin with the clinicopathological characteristics and prognosis of cholangiocarcinoma, and to analyze the molecular mechanisms of invasion and metastasis of the tumor. METHODS: EnVision immunohistochemistry was used to detect the expression of aPKC-iota and E-cadherin in 9 specimens of benign bile duct tissues, 35 specimens of cholangiocarcinoma and 6 specimens of metastatic cholangiocarcinoma. The relationship of the expression with clinicopathological characteristics, invasion and prognosis of cholangiocarcinoma was analyzed. A multivariate regression analysis was made of these data by the Cox proportional hazard model. RESULTS: The positive expression level of aPKC-iota in cholangiocarcinoma was remarkably higher than that in benign bile duct tissues (68.6% vs. 11.1%, P=0.006), but the expression level of E-cadherin was lower in cholangiocarcinoma than in benign bile duct tissues (37.1% vs. 88.9%, P=0.016). Correlation analysis revealed that the expression of aPKC-iota was positively related to tumor differentiation and invasion, whereas that of E-cadherin was entirely the contrary. Moreover, there was a negative relationship between the expression of aPKC-iota and that of E-cadherin (r=-0.287, P<0.05). Univariate analysis showed that the overall survival rate of the group with a higher expression of aPKC-iota in cholangiocarcinoma was remarkably lower than that of the group with a lower expression (P<0.01); multivariate analysis revealed that the expressions of aPKC-iota and E-cadherin are important prognostic factors for cholangiocarcinoma (P<0.05). CONCLUSIONS: The expressions of aPKC-iota and E-cadherin may reflect the differentiation and invasive potential of cholangiocarcinoma. aPKC-iota and E-cadherin may be independent prognostic factors and, when used in combination with clinicopathological characteristics, may increase the accuracy in predicting the prognosis of patients with cholangiocarcinoma. As a polar regulative associated protein, aPKC-iota may play an important role in the invasion and metastasis of cholangiocarcinoma.