Low expression of the putative tumour suppressor spinophilin is associated with higher proliferative activity and poor prognosis in patients with hepatocellular carcinoma

• Published in: British journal of cancer Vol. 108; no. 9; pp. 1830 - 1837
• Main Authors: AIGELSREITER, A, RESS, A. L, LACKNER, C, HAYBAECK, J, PICHLER, M, BETTERMANN, K, SCHAUER, S, KOLLER, K, EISNER, F, KIESSLICH, T, STOJAKOVIC, T, SAMONIGG, H, KORNPRAT, P
• Format: Journal Article
• Language: English
• Published: Basingstoke Nature Publishing Group 14.05.2013
• Subjects: Biological and medical sciences; Biomarkers; Biomarkers, Tumor - metabolism; Carcinoma, Hepatocellular - metabolism; Carcinoma, Hepatocellular - mortality; Cell Line, Tumor; Cell Proliferation; Cyclin D2 - biosynthesis; Disease-Free Survival; Female; Gastroenterology. Liver. Pancreas. Abdomen; Hep G2 Cells; Humans; Internal medicine; Kaplan-Meier Estimate; Ki-67 Antigen - metabolism; Liver cancer; Liver Neoplasms - metabolism; Liver Neoplasms - mortality; Liver. Biliary tract. Portal circulation. Exocrine pancreas; Male; Medical prognosis; Medical sciences; Microfilament Proteins - genetics; Microfilament Proteins - metabolism; Molecular Diagnostics; Multiple tumors. Solid tumors. Tumors in childhood (general aspects); Nerve Tissue Proteins - genetics; Nerve Tissue Proteins - metabolism; Prognosis; Proportional Hazards Models; Proteins; RNA Interference; RNA, Small Interfering; Surveillance; Survival Rate; Tumor Suppressor Protein p14ARF - metabolism; Tumor Suppressor Protein p53 - metabolism; Tumor Suppressor Proteins - genetics; Tumor Suppressor Proteins - metabolism; Tumors; Austria; Human; Immunohistochemistry; spinophilin; Prognosis; Hepatic disease; Hepatocellular carcinoma; Patient; Malignant tumor; Biological activity; Hypothesis; Liver cancer; Anatomic pathology; Association; Cancerology; Digestive diseases; Cancer; Tumor suppressor gene
• ISSN: 0007-0920; 1532-1827
• DOI: 10.1038/bjc.2013.165

Spinophilin, a multifunctional intracellular scaffold protein, is reduced in certain types of cancer and is regarded as a novel putative tumour suppressor protein. However, the role of spinophilin in hepatocellular carcinoma (HCC) has never been explored before. In this study, we determined for the first time the expression pattern of spinophilin in human HCC by immunohistochemistry and quantitative reverse transcriptase-PCR analysis. In addition, we performed immunohistochemical analysis of p53, p14(ARF) and the proliferation marker Ki-67. Kaplan-Meier curves and multivariate Cox proportional models were used to study the impact on clinical outcome. Small interfering RNA (siRNA) was used to silence spinophilin and to explore the effects of reduced spinophilin expression on cellular growth. In our study, complete loss of spinophilin immunoreactivity was found in 44 of 104 HCCs (42.3%) and reduced levels were found in an additional 37 (35.6%) cases. After adjusting for other prognostic factors, multivariate Cox regression analysis identified low expression of spinophilin as an independent prognostic factor with respect to disease-free (hazard ratio (HR)=1.8; 95% confidence interval (CI)=1.04-3.40; P=0.043) and cancer-specific survival (HR=2.0; CI=1.1-3.8; P=0.025). Reduced spinophilin expression significantly correlated with higher Ki-67 index in HCC (P=0.014). Reducing spinophilin levels by siRNA induced a higher cellular growth rate and increased cyclin D2 expression in tumour cells (P<0.05). This is the first study of the expression pattern and distribution of spinophilin in HCC. According to our data, the loss of spinophilin is associated with higher proliferation and might be useful as a prognostic marker in patients with HCC.