Annexin A1: A new immunohistological marker of cholangiocarcinoma

AIM: To evaluate a new immunohistological marker, annexin A1 (ANXA1), in cholangiocarcinoma (CCA) and hepatocellular carcinoma (HCC). METHODS: Expression of ANXA1 protein was investigated in liver tissues from patients with CCA and HCC by immunohistochemistry. Its expression on differences stages of tumor development was investigated in hamster CCA tissues induced by Opisthorchis viverrini and N -nitrosodimethylamine. Moreover, mRNA expression of ANXA1 was assessed in CCA cell lines by quantitative real-time polymerase chain reaction and silencing of ANXA1 gene expression using small interfering RNA. RESULTS: In human CCA tissue arrays, immunohistochemical analysis revealed that the positive expression of ANXA1 was 94.1% (64/68 cases) consisting of a high expression (66.2%, 45/68 cases) and a low expression (33.8%, 23/68 cases). However, expression of ANXA1 protein was negative in all histologic patterns for HCC (46/46 cases) and healthy individuals (6/6 cases). In hamster with opisthorchiasis-associated CCA, the expression of ANXA1 was observed in the cytoplasm of inflammatory cells, bile duct epithelia and tumor cells. Grading scores of ANXA1 expression were significantly increased with tumor progression. In addition, mRNA expression of ANXA1 significantly increased in all of the various CCA cell lines tested compared to an immortalized human cholangiocyte cell line (MMNK1). Suppressing the ANXA1 gene significantly reduced the matrix metalloproteinase (MMP) 2 and MMP9, and transforming growth factor-β genes, but increased nuclear factor-kB gene expression. CONCLUSION: ANXA1 is highly expressed in CCA, but low in HCC, suggesting it may serve as a new immunohistochemical marker of CCA. ANXA1 may play a role in opisthorchiasis-associated cholangiocarcinogenesis.     

Plasma IgG autoantibody against actin‐related protein 3 in liver fluke Opisthorchis viverrini infection

Opisthorchiasis secondary to Opisthorchis viverrini infection leads to cholangiocellular carcinoma through chronic inflammation of the bile ducts and possibly inducing autoimmunity. It was hypothesized that plasma autoantibodies directed against self‐proteins are biomarkers for opisthorchiasis. Plasma from patients with opisthorchiasis was tested using proteins derived from immortalized cholangiocyte cell lines, and spots reacting with plasma were excised and subjected to LC‐MS/MS. Seven protein spots were recognized by IgG autoantibodies, and the highest matching scored protein was actin‐related protein 3 (ARP3). The antibody against ARP3 was tested in plasma from 55 O. viverrini‐infected patients, 24 patients with others endemic parasitic infections and 17 healthy controls using Western blot and ELISA. Immunoreactivity against recombinant ARP3 was significantly more prevalent in opisthorchiasis compared to healthy controls at Western blotting and ELISA (P < 0·05). Plasma ARP3 autoantibody titres were also higher in opisthorchiasis compared to healthy individuals (P < 0·01) and other parasitic infections including Strongyloides stercoralis (P < 0·001), echinostome (P < 0·05), hookworms (P < 0·001) and Taenia spp. (P < 0·05). It was further characterized in that the ARP3 autoantibody titre had a sensitivity of 78·18% and specificity of 100% for opisthorchiasis. In conclusion, it may be suggested that plasma anti‐ARP3 might represent a new diagnostic antibody for opisthorchiasis.