Altered synemin could affect the organization of intermediate filament in human hepatocellular carcinoma.

Cells of human hepatocellular carcinoma (HCC) were morphologically different from those of normal liver. Intermediate filaments are important in building the architecture of liver cells and are proposed to interact with other cellular components. Synemin is one of intermediate filament associated proteins which can link between intermediate filament and other cytoskeletal structures. It was suggested that synemin might play some roles in tumorigenesis of hepatocellular cancinoma. In this study, we searched the synemin expression in 18 human HCCs by immunohistochemistry. The results revealed that synemin was modulated nearly in all human HCC cases. Many 0.4-0.8 microm-thick bundles were found in the IF extracts of liver and HCCs. These bundles were greater in diameter about 40 to 80 times of single IF. We speculated that the IFs were organized into the "filament bundles" to support the normal shape of the cells. That was, normal cell needed numerous synemin to lock the individual IF into stable "filament bundles". In cancer cells, the synemin was altered and this might lead to a loosened change of filament bundles, and the cancer cells would become pleomorphic.