Detection and identification of tumor-associated protein variants in human hepatocellular carcinomas

Abstract

The proteomic approach is a valuable tool to detect and identify proteins that are associated with cancer. In previous investigations on experimentally induced rat hepatomas, we detected aldose reductase-like protein (ARLP) as a highly significant marker protein. Our present study was intended to look for the presence of similar tumor-associated marker proteins on human hepatocellular carcinomas (HCC). We found several novel tumorassociated protein variants that represent members of the aldo-keto reductase (AKR) superfamily. Human aldose reductase-like protein-1 (hARLP-1) was the most prominent tumorassociated AKR member detected in HCC by 2-dimensional electrophoresis (2-DE) and identified by mass spectrometric fingerprinting. The enzyme was found in 4 distinct forms H uman hepatocellular carcinoma (HCC) ranks fifth in worldwide cancer incidence and is an important component of public health. Many HCC risk factors are known, including hepatitis B or C (HBV or HCV) infection, ingestion of aflatoxin-contaminated food, and alcohol. 1,2 The development of HCC is associated with multiple changes at the messenger RNA (mRNA) and/or protein level, some of them serving as tumor markers, e.g., ␣-fetoprotein, 3 or, less specifically, cyclin D1 or the proliferating cell nuclear antigen. 4 Misprogramming of genetic information in cancer is reflected by quantitative and/or qualitative protein alterations. These protein alterations might represent tumor markers that are useful in the diagnosis of human tumors and may also help the understanding of mechanisms of tumor induction and development. Proteome analysis of liver proteins and HCC were predominantly performed using either chemically induced hepatomas in animals (predominantly the rat 5-10 ) or human HCC cell lines, such as HepG2 and Huh7 cells, 11 BEL-7404 cells, 12 or HCC-M cells. 2,13,14 Numerous so-called tumor-associated or cancer-related proteins were identified; these provide valuable information for the establishment of HCC protein databases. 2,[11][12][13][14] Comparative analysis of liver tissue and hepatocellular carcinomas might give additional insights into the induction or repression of tumor-associ-

Vitamin C and diallyl sulfide as chemosensitizers to cisplatin in treating hepatocellular carcinoma

“…Several reports have shown that over-expression of AR in many tumor cells renders these cells resistant to chemotherapy and also demonstrate that inhibition of AR enhances sensitivity to chemotherapeutic drugs. 40,52,53 CONCLUSION Present data clearly demonstrate the chemo-sensitizing benefit of AA and DAS combination to CP therapy. These natural substances potentiated the effect of CP on almost all the parameters that could be affected in the course of hepatocarcinogenesis.…”

Hepatitis B virus X protein mutant upregulates CENP-A expression in hepatoma cells

“…Briefly, culture cells or tissues were lysed in buffer containing 10 mmol/l Tris (pH 7.4), 1% sodium dodecyl sulfate (SDS), 1 mmol/l sodium orthovanadate, and complete protease inhibitors (Roche). The extraction was accomplished using the Klose method as described previously (22,23). Samples of the lysates (50 µg) were then separated using SDS-polyacrylamide gel electrophoresis (SDS-PAGE), transferred to polyvinylidene fluoride membranes (Millipore, Bedford, MA), and blotted with the primary antibodies.…”

Diallyl sulfide protects against N -nitrosodiethylamineinduced liver tumorigenesis: Role of aldose reductase

“…Most of the AKR superfamily proteins are involved in the detoxification of a wide variety of substrates. Several reports have shown that over-expression of AR, in many tumor cells, renders these cells resistant to chemotherapy, and also demonstrate that inhibition of AR enhances cancer cell sensitivity to chemotherapeutic drugs [56,57] . In addition, over-expression of AR enhances production of ROS, which cause membrane damage and cellular leakage [58] .…”