Identification of proteins differentially expressed in gastric cancer cells with high metastatic potential for invasion to lymph nodes

In a search for proteins involved in cancer metastasis, we analyzed proteomes of the human gastric cancer cell OCUM-2M and its metastatic subline OCUM-2MLN. We observed that aspartate aminotransferase (AAT), D-site binding protein (DBP), and anterior gradient protein 2 (AGR2) are differentially expressed in metastatic OCUM-2MLN cells. Measurement of protein expression in clinical samples indicated that DBP and AAT are also down-regulated in metastatic adenocarcinoma. Additionally, urokinase-type tissue plasminogen activator is up-regulated in OCUM-2MLN cells and also in metastatic gastric cancer samples. Collectively, these results raise a possibility that AAT, DBP and AGR2 are functionally implicated in the invasiveness of gastric cancer cells.     

Association of P213S polymorphism of the L-selectin gene with type 2 diabetes and insulin resistance in Chinese population

Aims

L-selectin belongs to selectin family of adhesion molecule and participates in the generation and development of type 2 diabetes (T2D). In this study, we evaluated the relationship between the P213S polymorphism of L-selectin gene and T2D and insulin resistance in the Chinese population.

Methods

We genotyped P213S polymorphism in 801 patients with T2D and 834 healthy controls in the Chinese population using polymerase chain reaction–ligase detection reaction (PCR–LDR) technique. Plasma glucose, insulin, lipid, blood urea nitrogen, creatinine and uric acid levels were measured by biochemical technique.

Results

The frequency of 213PP genotype and P allele of the L-selectin gene in patients with T2D was significantly higher than that in controls (P = 0.007; P = 0.019, respectively). The relative risk of allele P suffered from T2D was 1.191 times higher than that of allele S. Moreover, the levels of FPG and HOMA-IR of PP and PS genotype carriers were significantly higher than those of SS genotype carriers in the T2D group (P < 0.05).

Conclusion

These findings indicated that the P213S polymorphism of L‐selectin gene may contribute to susceptibility to T2D and insulin resistance in the Chinese population, and P allele appears to be a risk factor for T2D.     

Significant associations of the rs2943634 (2q36.3) genetic polymorphism with adiponectin, high density lipoprotein cholesterol and ischemic stroke

Background

rs2943634 C/A single nucleotide polymorphism (SNP), located in a non coding region of chromosome 2q36.3, has been associated with coronary artery disease in two genome wide association studies. Our goal was to investigate its relation with myocardial infarction (MI) and ischemic stroke (IS), as well as with 12 intermediate risk phenotypes, in a population-based prospective cohort study.

Methods

rs2943634 was genotyped in a case-cohort study including a random sample of 1891 individuals (subcohort) and all incident MI (n = 211) and IS (n = 144) cases during a mean follow-up of 8.2 ± 2.2 years, nested within the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam cohort comprising 27,548 middle-aged men and women.

Results

rs2943634 minor allele (A) was associated in an additive fashion with lower risk of IS but not with MI [hazard ratio (HR) = 0.66; 95% confidence interval (CI): 0.50-0.87; P = 0.003; HR = 1.02; 95% CI: 0.82-1.28; P = 0.83 respectively, for the age and sex adjusted model]. Furthermore, it was related to slightly higher levels of plasma adiponectin [CC 6.94, CA 7.27, AA 7.86 μg/ml, P = 0.0002] and high density lipoprotein (HDL)-cholesterol (CC 52.08, CA 53.05 and AA 55.27 mg/dl, P = 0.002), based on additive models. Adjustment for adiponectin and HDL-cholesterol did not attenuate the association between the SNP and IS risk. In contrast, adjustment for adiponectin abolished the association between the SNP and HDL-cholesterol and adjustment for HDL-cholesterol attenuated the association between the SNP and adiponectin.

Conclusions

Our findings suggest that rs2943634 is associated with IS risk and with plasma levels of HDL-cholesterol and adiponectin in this German population. Further investigations are needed to confirm these results and to clarify the mechanisms underlying the association.     

Biomarkers predicting tumor response and evasion to anti-angiogenic therapy

No fully validated biological markers currently exist to predict responsiveness to or the development of evasion to anti-angiogenic therapy of cancer. The identification of such biomarkers is vital to move these therapies forward, as failure to respond to these treatments is often associated with rapid tumor progression that could have been averted had the intrinsic or acquired evasion to anti-angiogenic therapy been identified in a timely fashion. Furthermore, the high cost of antiangiogenic therapies makes it important to avoid utilizing them in the setting of lack of response or developing evasion, making the identification of biomarkers even more important. A number of potential physiologic, circulating, tissue, and imaging biomarkers have emerged from recently completed preclinical animal studies and clinical trials. In this review, we define 5 different types of biomarkers (physiologic, circulating, intratumoral, genetic polymorphisms, and radiographic); discuss the challenges in establishing biomarkers of antiangiogenic therapy in animal models and in clinical trials; and discuss future strategies to identify and validate biomarkers of anti-angiogenic therapy.     

Peripheral arterial stiffness is associated with higher baseline plasma uric acid: A prospective cohort study

This prospective cohort study aimed at identifying association between uric acid (UA) and peripheral arterial stiffness. A prospective cohort longitudinal study was performed according to an average of 4.8 years’ follow-up. The demographic data, anthropometric parameters, peripheral arterial stiffness (carotid-radial pulse-wave velocity, cr-PWV) and biomarker variables including UA were examined at both baseline and follow-up. Pearson’s correlations were used to identify the associations between UA and peripheral arterial stiffness. Further logistic regressions were employed to determine the associations between UA and arterial stiffness. At the end of follow-up, 1447 subjects were included in the analyses. At baseline, cr-PWV (r = 0.200, p < 0.001) was closely associated with UA. Furthermore, the follow-up cr-PWV (r = 0.145, p < 0.001) was also strongly correlated to baseline UA in Pearson’s correlation analysis. Multiple regressions also indicated the association between follow-up cr-PWV (β = 0.493, p = 0.013) and baseline UA level. Logistic regressions revealed that higher baseline UA level was an independent predictor of arterial stiffness severity assessed by cr-PWV at follow-up cross-section. Peripheral arterial stiffness is closely associated with higher baseline UA level. Furthermore, a higher baseline UA level is an independent risk factor and predictor for peripheral arterial stiffness.     

Genetic polymorphism of the vitamin D-binding protein (DBP) in crab-eating macaques (Macaca fascicularis)

Vitamin D-binding protein (DBP) of crab-eating macaques (Macaca fascicularis) was examined by means of three electrophoretic methods. DBP phenotypes were observed to be one or two bands in each method. All of DBP molecular variants could be detected by the simultaneous typing with these three methods. Family analysis suggested that DBP variants followed the mode of autosomal codominant inheritance. A total of 17 phenotypes governed by at least 11 alleles were observed in the populations of Malaysia, Indonesia, and the Philippines. The genetic variability was high in Malaysian and Indonesian populations but low in the Philippine population.     

Investigation of the genotoxicity of dibenzo[c,p]chrysene in human carcinoma MCF-7 cells in culture

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental pollutants that have been linked to certain human cancers. The fjord region PAH dibenzo[a,l]pyrene exhibits the highest levels of carcinogenic activity of all PAH as yet tested in rodent tumor models. Another hexacyclic aromatic hydrocarbon, dibenzo[c,p]chrysene (DBC), is a unique PAH that possesses one bay region and two fjord regions within the same molecule. Due to its structure, which is a merger of the fjord region PAHs benzo[c]phenanthrene, benzo[c]chrysene, and benzo[g]chrysene, DBC is of considerable research interest. In order to investigate the pathway of regioselective metabolism we have studied the cytotoxicity, metabolic activation and DNA adduct formation of DBC in human mammary carcinoma MCF-7 cells in culture. The cytotoxicity assay indicated undisturbed cell proliferation even at concentrations as high as 4.5 microM (1.5 micro g/ml) DBC. Concurrently, DNA adducts were detected in MCF-7 cells treated with DBC only in low amounts (0.6 pmol adducts/mg DNA). On the contrary, exposure to anti-DBC-1,2-diol-3,4-epoxide and anti-DBC-11,12-diol-13,14-epoxide, two putatively genotoxic metabolites of DBC, resulted in high levels of DNA adducts (33 and 51 pmol adducts/mg DNA, respectively). Although DBC was not efficiently transformed into DNA-reactive metabolites in MCF-7 cells in culture, the results from our study indicate that the two fjord region diol-epoxide derivatives of DBC may serve as ultimate genotoxic metabolites once they are enzymatically generated under certain circumstances in vitro or in vivo.     

Cross-talk among structural domains of human DBP upon binding 25-hydroxyvitamin D

Serum vitamin D-binding protein (DBP) is structurally very similar to serum albumin (ALB); both have three distinct structural domains and high cysteine-content. Yet, functionally they are very different. DBP possesses high affinity for vitamin D metabolites and G-actin, but ALB does not. It has been suggested that there may be cross-talk among the domains so that binding of one ligand may influence the binding of others. In this study we have employed 2-p-toluidinyl-6-sulfonate (TNS), a reporter molecule that fluoresces upon binding to hydrophobic pockets of DBP. We observed that recombinant domain III possesses strong binding for TNS, which is not influenced by 25-hydroxyvitamin D₃ (25-OH-D₃), yet TNS fluorescence of the whole protein is quenched by 25-OH-D₃. These results provide a direct evidence of cross-talk among the structural domains of DBP.     

Fatty acid-binding site environments of serum vitamin D-binding protein and albumin are different

Vitamin D-binding protein (DBP) and albumin (ALB) are abundant serum proteins and both possess high-affinity binding for saturated and unsaturated fatty acids. However, certain differences exist. We surmised that in cases where serum albumin level is low, DBP presumably can act as a transporter of fatty acids. To explore this possibility we synthesized several alkylating derivatives of ¹⁴C-palmitic acid to probe the fatty acid-binding pockets of DBP and ALB. We observed that N-ethyl-5-phenylisooxazolium-3′-sulfonate-ester (WRK-ester) of ¹⁴C-palmitic acid specifically labeled DBP; but p-nitrophenyl- and N-hydroxysuccinimidyl-esters failed to do so. However, p-nitrophenyl ester of ¹⁴C-palmitic acid specifically labeled bovine ALB, indicating that the micro-environment of the fatty acid-binding domains of DBP and ALB may be different; and DBP may not replace ALB as a transporter of fatty acids.