Shashikant Joshi

Publications (9) View all

• Source

  Available from: Xuezhi Bi

  Article: Proteomic analysis of colorectal cancer reveals alterations in metabolic pathways: mechanism of tumorigenesis.

  Xuezhi Bi, Qingsong Lin, Tet Wei Foo, Shashikant Joshi, Tao You, Han-Ming Shen, Choon Nam Ong, Peh Yean Cheah, Kong Weng Eu, Choy-Leong Hew
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  ABSTRACT: Colorectal cancer is the second leading killer cancer worldwide and presently the most common cancer among males in Singapore. The study aimed to detect changes of protein profiles associated with the process of colorectal tumorigenesis to identify specific protein markers for early colorectal cancer detection and diagnosis or as potential therapeutic targets. Seven pairs of colorectal cancer tissues and adjacent normal mucosa were examined by two-dimensional gel electrophoresis at basic pH range (pH 7-10). Intensity changes of 34 spots were detected with statistical significance. 16 of the 34 spots were identified by MALDI-TOF/TOF tandem mass spectrometry. Changes in protein expression levels revealed a significantly enhanced glycolytic pathway (Warburg effect), a decreased gluconeogenesis, a suppressed glucuronic acid pathway, and an impaired tricarboxylic acid cycle. Observed changes in protein abundance were verified by two-dimensional DIGE. These changes reveal an underlying mechanism of colorectal tumorigenesis in which the roles of impaired tricarboxylic acid cycle and the Warburg effect may be critical.
  Molecular &amp Cellular Proteomics 07/2006; 5(6):1119-30. · 7.40 Impact Factor
• Article: Proteomics profiling of epidermal mucus secretion of a cichlid (Symphysodon aequifasciata) demonstrating parental care behavior.

  Kenny Chong, Shashikant Joshi, Lam Toong Jin, Alexander Chong Shu-Chien
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  ABSTRACT: The discus fish (Symphysodon aequifasciata) is a cichlid demonstrating advanced mode of parental care towards fry. Both male and female fish utilized epidermal mucus secreted from specialized epidermal cells to feed developing fry. We utilized proteomics to compare protein profile from parental and nonparental fish. Gel analysis revealed a total of 35 spots that were up-regulated in parental mucus. In tandem, another 18 spots were uniquely expressed in parental mucus. MS analysis of these spots identified proteins such as fructose biphosphate aldolase, nucleoside diphosphate kinase, and heat shock proteins, which are essential to support energy provision, cell repair and proliferation, stress mediation, and defense mechanism in parental fish during parental-care period. Concurrently, the detection of several antioxidant-related proteins such as thioredoxin peroxidase and hemopexin suggests a need to overcome oxidative stress during hypermucosal production in parental-care behavior. A C-type lectin was also found to be uniquely expressed in parental mucus and could have important role in providing antimicrobial defense to both parental fish and fry. In summary, our study shows that discus mucus proteome undergoes changes in protein expression during parental-care period.
  PROTEOMICS 05/2006; 6(7):2251-8. · 4.51 Impact Factor
• Article: Heart extracellular matrix supports cardiomyocyte differentiation of mouse embryonic stem cells.

  Sayaka Higuchi, Qingsong Lin, Jigang Wang, Teck Kwang Lim, Shashikant B Joshi, Ganesh Srinivasan Anand, Maxey C M Chung, Michael P Sheetz, Hideaki Fujita
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  ABSTRACT: We have evaluated the effect of heart extracellular matrix (ECM) on the cardiomyocyte differentiation of mouse embryonic stem cells (ES cells) using de-cellularized heart tissue. Several lines of evidence indicate that ECM plays significant roles in cell proliferation, cell death and differentiation, but role of ECM possessing a 3D structure in differentiation has not been studied in detail. We found that there are substantial differences in the quantitative protein profiles of ECM in SDS-treated heart tissue compared to that of liver tissue, as assessed by iTRAQ™ quantitative proteomics analysis. When mouse ES cells were cultured on thin (60 μm) sections of de-cellularized tissue, the expression of cardiac myosin heavy chain (cMHC) and cardiac troponin I (cTnI) was high in ES cells cultured on heart ECM compared with those cultured on liver ECM. In addition, the protein expression of cMHC and cTnI was detected in cells on heart ECM after 2 weeks, which was not detectable in cells on liver ECM. These results indicate that heart ECM plays a critical role in the cardiomyocyte differentiation of ES cells. We propose that tissue-specific ECM induced cell lineage specification through mechano-transduction mediated by the structure, elasticity and components of ECM.
  Journal of Bioscience and Bioengineering 11/2012; · 1.79 Impact Factor
• Article: Differential recovery of membrane proteins after extraction by aqueous methanol and trifluoroethanol.

  Huoming Zhang, Qingsong Lin, Sukumar Ponnusamy, Narasimhan Kothandaraman, Teck Kwang Lim, Changqing Zhao, Hon Sook Kit, Biswas Arijit, Mary Rauff, Choy-Leong Hew, Maxey Ching Ming Chung, Shashikant B Joshi, Mahesh Choolani
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  ABSTRACT: Cell membrane proteome analysis is limited by inherent membrane hydrophobicity. Conventional membrane protein extraction techniques use detergents, chaotropes and organic acids that require sample clean-up or pH adjustment, and are associated with significant sample loss. We extracted membrane proteins from red blood cells (RBCs) using methanol (MeOH), trifluoroethanol (TFE) and urea, and identified membrane proteins using 2-D LC coupled with MALDI-TOF/TOF-MS. We show that organic solvents MeOH- and TFE-based methods have membrane protein analysis efficiencies comparable to urea, and are complementary for the recovery of both hydrophilic and hydrophobic peptides. The mean grand average of hydropathicity (GRAVY) value of identified peptides from the TFE-based method (-0.107) was significantly higher than that of the MeOH-based method (-0.465) (p<0.001). Sequential and adjunctive use of the organic solvents MeOH and TFE increases the number of proteins identified, and the confidence of their identification. We show that this strategy is effective for shotgun membrane proteome analysis.
  PROTEOMICS 05/2007; 7(10):1654-63. · 4.51 Impact Factor
• Article: SPLASH: systematic proteomics laboratory analysis and storage hub.

  Siaw Ling Lo, Tao You, Qingsong Lin, Shashikant B Joshi, Maxey C M Chung, Choy Leong Hew
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  ABSTRACT: In the field of proteomics, the increasing difficulty to unify the data format, due to the different platforms/instrumentation and laboratory documentation systems, greatly hinders experimental data verification, exchange, and comparison. Therefore, it is essential to establish standard formats for every necessary aspect of proteomics data. One of the recently published data models is the proteomics experiment data repository [Taylor, C. F., Paton, N. W., Garwood, K. L., Kirby, P. D. et al., Nat. Biotechnol. 2003, 21, 247-254]. Compliant with this format, we developed the systematic proteomics laboratory analysis and storage hub (SPLASH) database system as an informatics infrastructure to support proteomics studies. It consists of three modules and provides proteomics researchers a common platform to store, manage, search, analyze, and exchange their data. (i) Data maintenance includes experimental data entry and update, uploading of experimental results in batch mode, and data exchange in the original PEDRo format. (ii) The data search module provides several means to search the database, to view either the protein information or the differential expression display by clicking on a gel image. (iii) The data mining module contains tools that perform biochemical pathway, statistics-associated gene ontology, and other comparative analyses for all the sample sets to interpret its biological meaning. These features make SPLASH a practical and powerful tool for the proteomics community.
  PROTEOMICS 04/2006; 6(6):1758-69. · 4.51 Impact Factor