Biological characteristics of heat shock protein 90 in human liver cancer cells

Primary hepatic cancer refers to a malignant tumor that enables lethal cancero-metastasis. And hepatocellular carcinoma (HCC) is a most common cancer, accounting for around 75% of all cases. However, effective screening and diagnostic methods of HCC are limited currently. Heat shock protein 90 (HSP90), a sensitive biomarker, is found marked elevation in various malignancies. Thus, potential association between HSP90 expression and pathological onset of HCC is needed to be investigated. In current human study, plasma samples of advanced HCC patients were collected for biochemical assays, and cancer, non-cancer tissues from biopsy were stained immunohistochemically. In cell culture study, a human HepG2 cell line was subjected to a group of assays followed by HSP90 and inhibitor treatments. As results, the clinical data of HCC patients resulted in abnormal altered levels of serous molecules when compared to diagnostical references. However, these enzymatic changes showed no statistical significance. Significantly, plasma contents of HSP90 in HCC patients were elevated in comparison with those in HCC-free adults (P<0.01). As shown in immunofluorescence stains, hepatocellular HSP90-labeled cells in alpha fetoprotein (AFP)-positive and negative HCC sections were obviously expressed. In cell culture data, HSP90-induced HepG2 cells resulted in increased cell proliferation, and proliferating cell nuclear antigen (PCNA) , B-cell lymphoma 2 (Bcl-2)-positive cells (P<0.05). In addition, HSP90 inhibitor-treated HepG2 cells showed effectively reduced cell growth, and PCNA-, Bcl-2-positive cell counts. Taken together, our current findings demonstrate that hepatocellular HSP90 may be positively involved in development of HCC, and it is likely a potential biomarker for monitoring advanced HCC.