COMPARATIVE PROTEOMICS STUDIES OF SOLUBLE NUCLEAR PROTEINS OF DRUG SUSCEPTIBLE AND RESISTANT HUMAN BREAST CANCER MCF-7 CELLS

Drug resistance is a major obstacle in cancer chemotherapy. Better understanding of the mechanisms of the drug resistance can help to improve clinical treatment and develop new drugs. Since most anticancer drugs target the nuclei of the cancer cells, differential expression of nuclear proteins may play crucial roles as cancer cells acquire drug resistance. Thus I have carried out a comparative proteomics research project to study differential expression of nuclear proteins in drug resistant human breast cancer MCF-7 cells. Two dimensional gel electrophoresis and stable isotope labeling by amino acids in cell culture are used to conduct the study. Protein identification is acquired by peptide fingerprinting or microsequencing. Relative quantitation of the proteins is derived from gel comparisons and from ratios of labeled and unlabeled peptide pairs. A drug susceptible MCF-7 cell line and four drug resistant MCF-7 cell lines were examined. The drug resistant cell lines are resistant to different chemotherapeutic drugs and are well characterized. The known mechanisms of drug resistance can not satisfactorily answer how the drug resistance is conferred. One hundred and twenty proteins have been identified from the nuclear protein mixture of MCF-7 cells, from which more than 90% are classically categorized as nuclear proteins. Fourteen proteins are found to be significantly less or more abundant (more than 2 fold) in MCF-7 breast cancer cell lines resistant to etoposide, mitoxantrone, adriamycin in the presence of verapamil by both gel comparisons and isotope labeling. Abundances of cytoskeleton proteins, such as cytokeratin 8, cytokeratin 19, septin 2, and alpha tropomyosin, are altered in common across the three resistant cell lines. MCF-7 cell lines resistant to etoposide and mitoxantrone are more similar in protein abundance changes. Some of the proteins whose abundances are altered have also been reported to play important roles in resisting genotoxic stress in other normal and cancer cells. Their potential mechanistic contributions to drug resistance and implications for genetic regulation are discussed

OCLN as a novel biomarker for prognosis and immune infiltrates in kidney renal clear cell carcinoma: an integrative computational and experimental characterization

BackgroundOccludin (OCLN) is an important tight junction protein and has been reported to be abnormally expressed in the development of malignant tumors. However, its biomarker and carcinogenic roles in kidney renal clear cell carcinoma (KIRC) are less investigated.MethodsThe Cancer Genome Atlas database and Human Protein Atlas database were used to analyze the expression of OCLN in KIRC. UALCAN database and methylation-specific PCR assay were used to evaluate the methylation level of OCLN in KIRC. Univariate and multivariate Cox regression analyses were performed to model the prognostic significance of OCLN in KIRC patient cohorts. The correlation between OCLN expression and the immune cell infiltration, immune-related function and immune checkpoints were explored. Finally, EdU, scratch assay and transwell experiments were conducted to validate the role of OCLN in KIRC development.ResultsThe expression of OCLN was significantly downregulated in KIRC, compared with normal renal tissues (p<0.001). Patients with low OCLN expression showed a worse prognosis and poorer clinicopathological characteristics. Functional enrichment analysis revealed that OCLN was mainly involved in biological processes such as immune response, immunoglobulin complex circulating and cytokine and chemokine receptor to mediate KIRC development. Immune-related analysis indicated that OCLN could potentially serve as a candidate target for KIRC immunotherapy. OCLN overexpression inhibited proliferation, migration and invasion of KIRC cells in vitro.ConclusionOCLN was validated as a candidate prognostic biomarker and therapeutic target of KIRC based both on computational and experimental approaches. More in vivo experiments will be conducted to decode its molecular mechanism in KIRC carcinogenesis in the future work

Altered Tyrosine Phosphorylation of Cardiac Proteins Prompts Contractile Dysfunction in Hypertrophic Cardiomyopathy

Altered Serine/Threonine phosphorylation of the cardiac proteome is an established hallmark of heart failure (HF). However, the contribution of tyrosine phosphorylation to the pathogenesis of these diseases remains unclear. The cardiac proteome was explored by global mapping to discover and quantify site-specific tyrosine phosphorylation in two cardiac hypertrophic models; cardiac overexpression of ErbB2 (TgErbB2) and cardiac expression of a-Myosin heavy chain R403Q (R403Q-aMyHCTg) compared to control hearts. Phosphoproteomic changes found in R403Q-aMyHC Tg mice indicated EGFR1, Focal Adhesion, VEGF, ErbB signaling, and Chemokine signaling pathways activity were likely to be activated. On the other hand, TgErbB2 mice findings displayed significant overrepresentation of Right Ventricular Cardiomyopathy, Hypertrophic Cardiomyopathy (HCM), and dilated cardiomyopathy (DCM) KEGG Pathways. In silico kinase-substrate enrichment analysis (KSEA) highlighted a marked downregulation of canonical MAPK Pathway Activity downstream of k-Ras in TgErbB2 mice and activation of EGFR, PP2 inhibition of c-Src, and Hepatocyte growth factor stimulation. In vivo ErbB2 inhibition by AG-825 decreased cardiac fibrosis, cardiomyocyte disarray, and rescued contractile function on TgErbB2 mice. These results suggest that altered tyrosine phosphorylation may play a regulatory role in cardiac hypertrophic models, suggesting that tyrosine kinase inhibitors could be used therapeutically in Hypertrophic Cardiomyopathy

The Effects of Residual Chlorine on the Behavioural Responses of Daphnia magna in the Early Warning of Drinking Water Accidental Events

Biological Early Warning System (BEWS) based on behavioural responses of aquatic organisms was applied to monitor the drinking water quality for the early warning of accidental events. But residual chlorine in drinking water after disinfection might affect the behaviour modes of tested animals. In this research, the results showed that the residual chlorine in drinking water that was more than 0.32 mg/L would affect the behavioural responses of Daphnia magna significantly. It was evident dose-effect relationships between concentrations of residual chlorine and the behavioural responses of Daphnia magna. After 1.75 mg Na2S2O3 was added in 1 L water bodies, the behaviour modes of Daphnia magna would maintain the same as in Standard Reference Water (SRW). Therefore, in the early warning of drinking water accidental events, the effects of residual chlorine on the behavioural responses of Daphnia magna could be eliminated by on-line dosing of Na2S2O3. (C) 2011 Published by Elsevier B.V. Selection and/or peer-review under responsibility of School of Environment, Beijing Normal University

The Stepwise Behavioral Responses: Behavioral Adjustment of the Chinese Rare Minnow (Gobiocypris rarus) in the Exposure of Carbamate Pesticides

In order to illustrate the behavioral regulation in environmental stress, the behavioral responses of the Chinese rare minnow (Gobiocypris rarus) to arprocarb, carbofuran, and oxamyl were analyzed with an online monitoring system. The Self-Organizing Map (SOM) was used to define the patterns of the behavioral data obtained from treatments at concentrations of 0.1 toxic unit (TU), 1 TU, 2 TU, 5 TU, 10 TU, and 20 TU and a control. In certain cases, differences among the carbamate pesticides (CPs) tested were observed. The profiles of behavioral strength (BS) in SOM varied according to the concentration used. The time of the first significant decrease of the BS varied inversely with the CP concentrations. The results suggested that the behavioral regulation in the stepwise behavioral responses (SBR) was evident. The primary movement behaviors shown by the SBR model included no effect, stimulation, acclimation, adjustment (readjustment), and toxic effect, especially at the lower concentrations. However, higher stress (10 TU and 20 TU) might limit the function of the behavioral adjustment produced by the intrinsic response mechanisms. It was concluded that SBR, which were affected by both the concentration and the exposure time, could be used as a suitable indicator in the ecotoxicological risk assessment of CPs