Comparative proteomic analysis of plasma membrane proteins between human osteosarcoma and normal osteoblastic cell lines

<p>Abstract</p> <p>Background</p> <p>Osteosarcoma (OS) is the most common primary malignant tumor of bone in children and adolescents. However, the knowledge in diagnostic modalities has progressed less. To identify new biomarkers for the early diagnosis of OS as well as for potential novel therapeutic candidates, we performed a sub-cellular comparative proteomic research.</p> <p>Methods</p> <p>An osteosarcoma cell line (MG-63) and human osteoblastic cells (hFOB1.19) were used as our comparative model. Plasma membrane (PM) was obtained by aqueous two-phase partition. Proteins were analyzed through iTRAQ-based quantitative differential LC/MS/MS. The location and function of differential proteins were analyzed through GO database. Protein-protein interaction was examined through String software. One of differentially expressed proteins was verified by immunohistochemistry.</p> <p>Results</p> <p>342 non-redundant proteins were identified, 68 of which were differentially expressed with 1.5-fold difference, with 25 up-regulated and 43 down-regulated. Among those differential proteins, 69% ware plasma membrane, which are related to the biological processes of binding, cell structure, signal transduction, cell adhesion, etc., and interaction with each other. One protein--CD151 located in net nodes was verified to be over-expressed in osteosarcoma tissue by immunohistochemistry.</p> <p>Conclusion</p> <p>It is the first time to use plasma membrane proteomics for studying the OS membrane proteins according to our knowledge. We generated preliminary but comprehensive data about membrane protein of osteosarcoma. Among these, CD151 was further validated in patient samples, and this small molecule membrane might be a new target for OS research. The plasma membrane proteins identified in this study may provide new insight into osteosarcoma biology and potential diagnostic and therapeutic biomarkers.</p

PNPLA3 gene-by-visceral adipose tissue volume interaction and the pathogenesis of fatty liver disease: The NHLBI Family Heart Study

BACKGROUND: Fatty liver disease (FLD) is characterized by increased intrahepatic triglyceride content with or without inflammation and is associated with obesity, and features of the metabolic syndrome. Several recent GWAS have reported an association between SNP rs738409 in the PNPLA3 gene and FLD. Liver attenuation (Hounsfield Units, HU) by computed tomography is a non-invasive measure of liver fat, with lower values of HU indicating higher liver fat content. Clinically, a liver attenuation (LA) value of ≤ 40 HU indicates moderate-to-severe hepatic steatosis. OBJECTIVE: We investigated whether missense rs738409 PNPLA3 interacted with abdominal visceral adipose tissue volume (cm(3)) to reduce liver attenuation (i.e. increased liver fat) in 1,019 European American men and 1,238 European American women from the Family Heart Study. METHODS: We used linear regression to test the additive effect of genotype, abdominal visceral adipose tissue (VAT), and their multiplicative interaction on LA adjusted for age, BMI, HDL-cholesterol, insulin resistance, serum triglycerides, abdominal subcutaneous adipose tissue, and alcohol intake. RESULTS: In men and women combined, the interaction between each copy of the rs738409 variant allele (MAF 0.23) and 100cm(3)/150mm slice VAT decreased LA by 2.68±0.35 HU (p < 0.01). The interaction of 100cm(3) VAT and the variant allele was associated with a greater decrease in LA in women than men (−4.8±0.6 and −2.2±0.5 HU, respectively). CONCLUSIONS: The interaction between genotype and VAT volume suggest key differences in the role of PNPLA3 genotype in conjunction with abdominal VAT in liver fat accrual. The stronger association of the PNPLA3 genotype and liver fat in women suggests that women may be more sensitive to liver fat accumulation in the setting of increased visceral fat, compared to men. The presence of the PNPLA3 variant genotype, particularly in the context of high visceral adipose tissue content may play an important role in FLD

NAFLD-Associated Hepatocellular Carcinoma: a Threat to Patients with Metabolic Disorders

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide, and its prevalence is increasing in relation to the epidemics of obesity and type 2 diabetes mellitus, via non-alcoholic fatty liver disease (NAFLD). Unhealthy lifestyles associated with metabolic disorders are per se risk conditions for NAFLD progression, and specific gene polymorphisms may also favor oncogenesis, particularly in the presence of advanced fibrosis or cryptogenic cirrhosis. However, NAFLD-associated HCC may also develop in noncirrhotic NAFLD and is frequently diagnosed at a more advanced tumor stage, compared with virus/alcohol-related HCC. This highlights the need for screening programs and long-term surveillance for earlier HCC detection in patients with metabolic risk factors, a policy hindered by the large number of cases at risk, with costs unaffordable by National health systems. New screening tools and cost-utility studies are eagerly awaited to develop more appropriate programs for early detection and treatment of NAFLD-associated HCC