Surfaceome profiling enables isolation of cancer-specific exosomal cargo in liquid biopsies from pancreatic cancer patients.

Background: Detection of circulating tumor DNA can be limited due to their relative scarcity in circulation, particularly while patients are actively undergoing therapy. Exosomes provide a vehicle through which cancer-specific material can be enriched from the compendium of circulating non-neoplastic tissue-derived nucleic acids. We carried out a comprehensive profiling of the pancreatic ductal adenocarcinoma (PDAC) exosomal 'surfaceome' in order to identify surface proteins that will render liquid biopsies amenable to cancer-derived exosome enrichment for downstream molecular profiling. Patients and methods: Surface exosomal proteins were profiled in 13 human PDAC and 2 non-neoplastic cell lines by liquid chromatography-mass spectrometry. A total of 173 prospectively collected blood samples from 103 PDAC patients underwent exosome isolation. Droplet digital PCR was used on 74 patients (136 total exosome samples) to determine baseline KRAS mutation call rates while patients were on therapy. PDAC-specific exosome capture was then carried out on additional 29 patients (37 samples) using an antibody cocktail directed against selected proteins, followed by droplet digital PCR analysis. Exosomal DNA in a PDAC patient resistant to therapy were profiled using a molecular barcoded, targeted sequencing panel to determine the utility of enriched nucleic acid material for comprehensive molecular analysis. Results: Proteomic analysis of the exosome 'surfaceome' revealed multiple PDAC-specific biomarker candidates: CLDN4, EPCAM, CD151, LGALS3BP, HIST2H2BE, and HIST2H2BF. KRAS mutations in total exosomes were detected in 44.1% of patients undergoing active therapy compared with 73.0% following exosome capture using the selected biomarkers. Enrichment of exosomal cargo was amenable to molecular profiling, elucidating a putative mechanism of resistance to PARP inhibitor therapy in a patient harboring a BRCA2 mutation. Conclusion: Exosomes provide unique opportunities in the context of liquid biopsies for enrichment of tumor-specific material in circulation. We present a comprehensive surfaceome characterization of PDAC exosomes which allows for capture and molecular profiling of tumor-derived DNA.

Association of Single Nucleotide Polymorphisms of Adiponectin Gene with Type 2 Diabetes Mellitus, and Their Influence on Cardiovascular Risk Markers.

Type 2 diabetes mellitus is a genetically heterogeneous condition, characterized by insulin deficiency and/or insulin resistance. The etiology of type 2 diabetes is complex, with involvement of genetic and environmental factors. The adipose tissue protein 'adiponectin' is known to increase insulin sensitivity with decreased risk of type 2 diabetes mellitus. The gene for adiponectin is present on chromosome 3q27, the association of number of single nucleotide polymorphisms of adiponectin gene with type 2 diabetes and its complications have been reported. In the present study the two most common SNPs +45T/G & +276G/T, and their association with type 2 diabetes mellitus and cardiovascular markers were studied. The significant difference in genotype frequencies of +45T/G & +276G/T was found in type 2 diabetic patients and controls, with odds ratio of 1.13 & 1.26 respectively. BMI, Fasting blood glucose, fasting insulin, HOMA IR, triglyceride and VLDL cholesterol levels were increased, and HDL cholesterol level was decreased in patients carrier for +45T/G SNP than the wild type. While only decrease in the HDL cholesterol was reported in carriers for SNP +276G/T than the wild type. The logistic regression analysis revealed the positive association of SNP +45T/G with total cholesterol & LDL cholesterol. And negative association of HDL cholesterol was found with SNPs +45T/G and +276G/T. The haplotype analysis shows the alterations in means of biochemical markers in the patients having haplotype (GG) for mutant allele of SNP +45T/G and wild allele for SNP +276G/T.

Study of Common Genetic Variant S447X in Lipoprotein Lipase and Its Association with Lipids and Lipoproteins in Type 2 Diabetic Patients.

Elevated plasma triglyceride and non-esterified fatty acid concentrations may cause insulin resistance and type 2 diabetes mellitus. Lipoprotein lipase (LPL) is a rate-determining enzyme in lipid metabolism. A variant in the LPL gene has been identified which alters the penultimate amino acid Serine at 447 to a stop codon (S447X), and results in a truncated LPL molecule lacking the C-terminal dipeptide Ser-Gly. The present study was designed to evaluate the frequency of S447X variant in the LPL gene and its effect on the lipid and lipoprotein levels in type 2 diabetic subjects. The genotype frequency distributions of type 2 diabetes patients and controls were in Hardy-Weinberg equilibrium. Comparison of the genotype and allelic frequencies of S447X in subjects with type 2 diabetics compared to controls demonstrated no significant difference. In subjects with type 2 diabetics having hypertriglyceridemia (TG ≥ 150 mg/dl) compared to diabetics with TG level <150 mg/dl, significant difference in genotype frequency was found among these groups, while allelic frequency of X was significantly differed. Logistic regression analysis showed the negative association of LPL S447X variant with TG and VLDL cholesterol, while no association with total cholesterol, HDL cholesterol and LDL cholesterol was found. The lipid levels except for HDL cholesterol were found to be significantly lower in carriers for S447X than wild type in diabetes group. The decreased level of TG and TG rich lipoprotein in subjects with SNP S447X in LPL, predicts anti-atherogenic activity of carriers for S447X variant in general population as well as type 2 diabetic patients.

Expression profiling stratifies mesothelioma tumors and signifies deregulation of spindle checkpoint pathway and microtubule network with therapeutic implications.

BACKGROUND: Malignant pleural mesothelioma (MPM) is a lethal neoplasm exhibiting resistance to most treatment regimens and requires effective therapeutic options. Though an effective strategy in many cancer, targeted therapy is relatively unexplored in MPM because the therapeutically important oncogenic pathways and networks in MPM are largely unknown. MATERIALS AND METHODS: We carried out gene expression microarray profiling of 53 surgically resected MPMs tumors along with paired normal tissue. We also carried out whole transcriptomic sequence (RNA-seq) analysis on eight tumor specimens. Taqman-based quantitative Reverse-transcription polymerase chain reaction (qRT-PCR), western analysis and immunohistochemistry (IHC) analysis of mitotic arrest deficient-like 1 (MAD2L1) was carried out on tissue specimens. Cell viability assays of MPM cell lines were carried out to assess sensitivity to specific small molecule inhibitors. RESULTS: Bioinformatics analysis of the microarray data followed by pathway analysis revealed that the mitotic spindle assembly checkpoint (MSAC) pathway was most significantly altered in MPM tumors with upregulation of 18 component genes, including MAD2L1 gene. We validated the microarray data for MAD2L1 expression using quantitative qRT-PCR and western blot analysis on tissue lysates. Additionally, we analyzed expression of the MAD2L1 protein by IHC using an independent tissue microarray set of 80 MPM tissue samples. Robust clustering of gene expression data revealed three novel subgroups of tumors, with unique expression profiles, and showed differential expression of MSAC pathway genes. Network analysis of the microarray data showed the cytoskeleton/spindle microtubules network was the second-most significantly affected network. We also demonstrate that a nontaxane small molecule inhibitor, epothilone B, targeting the microtubules have great efficacy in decreasing viability of 14 MPM cell lines. CONCLUSIONS: Overall, our findings show that MPM tumors have significant deregulation of the MSAC pathway and the microtubule network, it can be classified into three novel molecular subgroups of potential therapeutic importance and epothilone B is a promising therapeutic agent for MPM.

Apolipoprotein e gene polymorphism and its effect on plasma lipids in arteriosclerosis.

BACKGROUND & OBJECTIVES: Myocardial infarction and stroke are leading causes of death worldwide. Primarily, arteriosclerosis is responsible for these events. There is a strong family history suggesting a genetic cause. Apolipoprotein E (apo E) plays an important role in lipid metabolism. Apo E is polymorphic with three isoforms, ApoE2, ApoE3 and ApoE4; which translate into three alleles of the gene. Its polymorphism may be a risk determinant of atherosclerosis. METHODS: Lipoprotein concentrations were studied, in 100 myocardial infarction and 50 cerebrovascular stroke subjects and compared with age and sex matched controls. Genotypes for apo E isoforms (E2, E3, and E4) for all above subjects and age and sex matched controls were determined by Multiplex Amplification Refractory Mutation System PCR. RESULTS: There were statistically significant higher values of serum total cholesterol and LDL cholesterol in study group, as compared to control group. Study of Apo E isoforms revealed higher proportion of E4 allele in the study group as compared to control group. The occurrence of each allele frequency in study and control group was E4E4: 28.66% and 16.0%, E3E3: 39.33% and 56.66%, E4E3: 14.66% and 9.33%, E3E2: 8.66% and 10.66%, E4E2: 4.66% and 2.66% & for E2E2: 4.0% and 4.66% respectively. INTERPRETATION & CONCLUSION: There were significantly higher levels of serum total cholesterol, LDL cholesterol and triglyceride with E4 allele; when compared with in the study group and between study group and control group. Apo E polymorphism influences serum lipid levels and is an independent risk determinant of arteriosclerosis.