Urine metabolomic analysis identifies potential biomarkers and pathogenic pathways in kidney cancer

Kidney cancer is the seventh most common cancer in the Western world, its incidence is increasing, and it is frequently metastatic at presentation, at which stage patient survival statistics are grim. In addition, there are no useful biofluid markers for this disease, such that diagnosis is dependent on imaging techniques that are not generally used for screening. In the present study, we use metabolomics techniques to identify metabolites in kidney cancer patients' urine, which appear at different levels (when normalized to account for urine volume and concentration) from the same metabolites in nonkidney cancer patients. We found that quinolinate, 4-hydroxybenzoate, and gentisate are differentially expressed at a false discovery rate of 0.26, and these metabolites are involved in common pathways of specific amino acid and energetic metabolism, consistent with high tumor protein breakdown and utilization, and the Warburg effect. When added to four different (three kidney cancer-derived and one "normal") cell lines, several of the significantly altered metabolites, quinolinate, α-ketoglutarate, and gentisate, showed increased or unchanged cell proliferation that was cell line-dependent. Further evaluation of the global metabolomics analysis, as well as confirmation of the specific potential biomarkers using a larger sample size, will lead to new avenues of kidney cancer diagnosis and therapy.     

Human papillomaviruses and the specificity of PDZ domain targeting

The human papillomavirus (HPV) E6 oncoprotein is fundamental to the ability of these viruses to induce human malignancy. A defining characteristic of the HPV E6 oncoproteins found in cancer-causing HPV types is the presence of a PDZ binding motif at their extreme C-terminus. Through this motif, E6 is able to interact with a large number of cellular proteins that contain PDZ domains. Many of these cellular proteins are involved in regulation of processes associated with the control of cell attachment, cell proliferation, cell polarity and cell signaling. How E6 targets multiple proteins containing the same recognition domain is still an open question. In this review, we highlight aspects of E6 function and biology that help to answer this question, and thereby provide insight into the role of these substrates during development of HPV-induced malignancy.     

Integrating research and education at research-extensive universities with research-intensive communities

Although the Boyer Commission (1998) lamented the lack of research opportunities for all undergraduates at research-extensive universities, it did not provide a feasible solution consistent with the mandate for faculty to maintain sustainable physiology research programs. The costs associated with one-on-one mentoring, and the lack of a sufficient number of faculty members to give intensive attention to undergraduate researchers, make one-on-one mentoring impractical. We therefore developed and implemented the "research-intensive community" model with the aim of aligning diverse goals of participants while simultaneously optimizing research productivity. The fundamental organizational unit is a team consisting of one graduate student and three undergraduates from different majors, supervised by a faculty member. Undergraduate workshops, Graduate Leadership Forums, and computer-mediated communication provide an infrastructure to optimize programmatic efficiency and sustain a multilevel, interdisciplinary community of scholars dedicated to research. While the model radically increases the number of undergraduates that can be supported by a single faculty member, the inherent resilience and scalability of the resulting complex adaptive system enables a research-intensive community program to evolve and grow.     

Chemical modification of mono-cysteine mutants allows a more global look at conformations of the ε subunit of the ATP synthase from <Emphasis Type="Italic">Escherichia coli</Emphasis>

The ε subunit of the ATP synthase from E. coli undergoes conformational changes while rotating through 360° during catalysis. The conformation of ε was probed in the membrane-bound ATP synthase by reaction of mono-cysteine mutants with 3-N-maleimidyl-propionyl biocytin (MPB) under resting conditions, during ATP hydrolysis, and after inhibition by ADP-AlF₃. The relative extents of labeling were quantified after electrophoresis and blotting of the partially purified ε subunit. Residues from the N-terminal β-sandwich domain showed a position-specific pattern of labeling, consistent with prior structural studies. Some residues near the ε-γ interface showed changes up to two-fold if labeling occurred during ATP hydrolysis or after inhibition by ADP-AlF₃. In contrast, residues found in the C-terminal α-helices were all labeled to a moderate or high level with a pattern that was consistent with a partially opened helical hairpin. The results indicate that the two C-terminal α-helices do not adopt a fixed conformation under resting conditions, but rather exhibit intrinsic flexibility.     

Mechanics of the left ventricular myocardial interstitium: effects of acute and chronic myocardial edema

Myocardial interstitial edema forms as a result of several disease states and clinical interventions. Acute myocardial interstitial edema is associated with compromised systolic and diastolic cardiac function and increased stiffness of the left ventricular chamber. Formation of chronic myocardial interstitial edema results in deposition of interstitial collagen, which causes interstitial fibrosis. To assess the effect of myocardial interstitial edema on the mechanical properties of the left ventricle and the myocardial interstitium, we induced acute and chronic interstitial edema in dogs. Acute myocardial edema was generated by coronary sinus pressure elevation, while chronic myocardial edema was generated by chronic pulmonary artery banding. The pressure-volume relationships of the left ventricular myocardial interstitium and left ventricular chamber for control animals were compared with acutely and chronically edematous animals. Collagen content of nonedematous and chronically edematous animals was also compared. Generating acute myocardial interstitial edema resulted in decreased left ventricular chamber compliance compared with nonedematous animals. With chronic edema, the primary form of collagen changed from type I to III. Left ventricular chamber compliance in animals made chronically edematous was significantly higher than nonedematous animals. The change in primary collagen type secondary to chronic left ventricular myocardial interstitial edema provides direct evidence for structural remodeling. The resulting functional adaptation allows the chronically edematous heart to maintain left ventricular chamber compliance when challenged with acute edema, thus preserving cardiac function over a wide range of interstitial fluid pressures.     

Variations in the GST activity are associated with single and combinations of GST genotypes in both male and female diabetic patients

In the present cross sectional study, we aimed to ascertain the relative associations of GST genotypes with GST activity variations and also with the risk to DMT2 predisposition among men and women separately. Clinical samples obtained from 244 DMT2 cases (120 Males and 124 Females) and 228 controls (117 Males and 111 Females) belonging to Asian Indian ethnicity were used to test for glycemic index, lipid profile, GST activity and GST genotypes. The frequencies of single and combinations of GST genotypes were statistically examined for their association with DMT2 risk among both study groups. The GST activity is significantly lowered in DMT2 group compared to controls (p = < 0.001). This reduction is found to be subjective to single and combinations of GST genotypes among diabetic patients. The frequency distribution for single, double and triple combinations of genotypes of GSTT1, GSTM1 and GSTP1 showed the varying degrees of association with DMT2 risk from 0.5 to 5.6-fold among male and female patients (for all associations, p value was <0.05). Interestingly, GST activity was lowered in both male and female patients with single or combinational genotypes of GSTM1 (Null), GSTT1 (Null), and P1 (V/V) (for all associations, p value was = <0.0001). The reduced anti-oxidant capacity among diabetic patients with certain GST genotypes may have some important implications for disease diagnosis and therapy.