Hepatic somatostatin receptor 2 expression during premalignant stages of hepatocellular carcinoma

Abstract

Growth and antigrowth hormones were occasionally investigated in hepatocarcinoma. Somatostatin regulates cell proliferation and inhibits the secretion of many growth factors engaged to tumors through a group of receptors, including somatostatin receptor type 2 (SSTR2). Caspase-3 is a transcription factor which is elevated in liver cancers. The most commonly approved marker for liver cancer is alpha fetoprotein (AFP), although it has no more than 65% sensitivity and specificity. Hepatocarcinoma is also mediated by oxidative stress. Four groups of mice were used in this work: a control group and another three groups (Gp 2, 3, and 4) used for induction of HCC with a single subnecrotic dose of diethylnitrosamine (DENA). Gp 2 was sacrificed on the last day after 8 weeks, Gp 3 after 16 weeks, and Gp 4 after 24 weeks. Both liver tissue SSR2 protein and mRNA, liver AFP, and caspase-3 mRNA expression, concomitant to tissue malondialdehyde (MDA), were significantly elevated with depressed reduced glutathione (GSH). The change was much more prominent and stage dependent for SSR2. These effects were supported by graded histological abnormalities. The study encourages the use of liver tissue SSR2 protein and mRNA as a reliable tumor marker for liver cancer rather than AFP which is always misleading during silent stages of hepatocarcinogenesis.