56 research outputs found
Urinary Volatomic Expression Pattern: Paving the Way for Identification of Potential Candidate Biosignatures for Lung Cancer
The urinary volatomic profiling of Indian cohorts composed of 28 lung cancer (LC) pa tients and 27 healthy subjects (control group, CTRL) was established using headspace solid phase
microextraction technique combined with gas chromatography mass spectrometry methodology
as a powerful approach to identify urinary volatile organic metabolites (uVOMs) to discriminate
among LC patients from CTRL. Overall, 147 VOMs of several chemistries were identified in the
intervention groups—including naphthalene derivatives, phenols, and organosulphurs—augmented
in the LC group. In contrast, benzene and terpenic derivatives were found to be more prevalent in
the CTRL group. The volatomic data obtained were processed using advanced statistical analysis,
namely partial least square discriminative analysis (PLS-DA), support vector machine (SVM), random
forest (RF), and multilayer perceptron (MLP) methods. This resulted in the identification of nine
uVOMs with a higher potential to discriminate LC patients from CTRL subjects. These were furan,
o-cymene, furfural, linalool oxide, viridiflorene, 2-bromo-phenol, tricyclazole, 4-methyl-phenol, and
1-(4-hydroxy-3,5-di-tert-butylphenyl)-2-methyl-3-morpholinopropan-1-one. The metabolic pathway
analysis of the data obtained identified several altered biochemical pathways in LC mainly affecting
glycolysis/gluconeogenesis, pyruvate metabolism, and fatty acid biosynthesis. Moreover, acetate
and octanoic, decanoic, and dodecanoic fatty acids were identified as the key metabolites responsible
for such deregulation. Furthermore, studies involving larger cohorts of LC patients would allow us
to consolidate the data obtained and challenge the potential of the uVOMs as candidate biomarkers
for LC.info:eu-repo/semantics/publishedVersio
F-box protein FBXO16 functions as a tumor suppressor by attenuating nuclear beta-catenin function
Aberrant activation of beta-catenin has been implicated in a variety of human diseases, including cancer. In spite of significant progress, the regulation of active Wnt/beta-catenin-signaling pathways is still poorly understood. In this study, we show that F-box protein 16 (FBXO16) is a putative tumor suppressor. It is a component of the SCF (SKP1-Cullin1-F-box protein) complex, which targets the nuclear beta-catenin protein to facilitate proteasomal degradation through the 26S proteasome. FBXO16 interacts physically with the C-terminal domain of beta-catenin and promotes its lysine 48-linked polyubiquitination. In addition, it inhibits epithelial-to-mesenchymal transition (EMT) by attenuating the level of beta-catenin. Therefore, depletion of FBXO16 leads to increased levels of beta-catenin, which then promotes cell invasion, tumor growth, and EMT of cancer cells. Furthermore, FBXO16 and beta-catenin share an inverse correlation of cellular expression in clinical breast cancer patient samples. In summary, we propose that FBXO16 functions as a putative tumor suppressor by forming an SCF(FBXO16) complex that targets nuclear beta-catenin in a unique manner for ubiquitination and subsequent proteasomal degradation to prevent malignancy. This work suggests a novel therapeutic strategy against human cancers related to aberrant beta-catenin activation
Comprehensive analysis of temporal alterations in cellular proteome of bacillus subtilis under curcumin treatment
Curcumin is a natural dietary compound with antimicrobial activity against various gram positive and negative bacteria. This study aims to investigate the proteome level alterations in Bacillus subtilis due to curcumin treatment and identification of its molecular/cellular targets to understand the mechanism of action. We have performed a comprehensive proteomic analysis of B. subtilis AH75 strain at different time intervals of curcumin treatment (20, 60 and 120 min after the drug exposure, three replicates) to compare the protein expression profiles using two complementary quantitative proteomic techniques, 2D-DIGE and iTRAQ. To the best of our knowledge, this is the first comprehensive longitudinal investigation describing the effect of curcumin treatment on B. subtilis proteome. The proteomics analysis revealed several interesting targets such UDP-N-acetylglucosamine 1-carboxyvinyltransferase 1, putative septation protein SpoVG and ATP-dependent Clp protease proteolytic subunit. Further, in silico pathway analysis using DAVID and KOBAS has revealed modulation of pathways related to the fatty acid metabolism and cell wall synthesis, which are crucial for cell viability. Our findings revealed that curcumin treatment lead to inhibition of the cell wall and fatty acid synthesis in addition to differential expression of many crucial proteins involved in modulation of bacterial metabolism. Findings obtained from proteomics analysis were further validated using 5-cyano-2,3-ditolyl tetrazolium chloride (CTC) assay for respiratory activity, resazurin assay for metabolic activity and membrane integrity assay by potassium and inorganic phosphate leakage measurement. The gene expression analysis of selected cell wall biosynthesis enzymes has strengthened the proteomics findings and indicated the major effect of curcumin on cell division
Understanding HIV-Mycobacteria synergism through comparative proteomics of intra-phagosomal mycobacteria during mono- and HIV co-infection
Mycobacterium tuberculosis (Mtb) is the most common co-infection in HIV patients and a serious co-epidemic. Apart from increasing the risk of reactivation of latent tuberculosis (TB), HIV infection also permits opportunistic infection of environmental non-pathogenic mycobacteria. To gain insights into mycobacterial survival inside host macrophages and identify mycobacterial proteins or processes that influence HIV propagation during co-infection, we employed proteomics approach to identify differentially expressed intracellular mycobacterial proteins during mono- and HIV co-infection of human THP-1 derived macrophage cell lines. Of the 92 proteins identified, 30 proteins were upregulated during mycobacterial mono-infection and 40 proteins during HIV-mycobacteria co-infection. We observed down-regulation of toxin-antitoxin (TA) modules, up-regulation of cation transporters, Type VII (Esx) secretion systems, proteins involved in cell wall lipid or protein metabolism, glyoxalate pathway and branched chain amino-acid synthesis during co-infection. The bearings of these mycobacterial factors or processes on HIV propagation during co-infection, as inferred from the proteomics data, were validated using deletion mutants of mycobacteria. The analyses revealed mycobacterial factors that possibly via modulating the host environment, increased viral titers during co-infection. The study provides new leads for investigations towards hitherto unknown molecular mechanisms explaining HIV-mycobacteria synergism, helping address diagnostics and treatment challenges for effective co-epidemic management
Mass Spectrometry-Based Proteomics in Molecular Diagnostics: Discovery of Cancer Biomarkers Using Tissue Culture
Accurate diagnosis and proper monitoring of cancer patients remain a key obstacle for successful cancer treatment and prevention. Therein comes the need for biomarker discovery, which is crucial to the current oncological and other clinical practices having the potential to impact the diagnosis and prognosis. In fact, most of the biomarkers have been discovered utilizing the proteomics-based approaches. Although high-throughput mass spectrometry-based proteomic approaches like SILAC, 2D-DIGE, and iTRAQ are filling up the pitfalls of the conventional techniques, still serum proteomics importunately poses hurdle in overcoming a wide range of protein concentrations, and also the availability of patient tissue samples is a limitation for the biomarker discovery. Thus, researchers have looked for alternatives, and profiling of candidate biomarkers through tissue culture of tumor cell lines comes up as a promising option. It is a rich source of tumor cell-derived proteins, thereby, representing a wide array of potential biomarkers. Interestingly, most of the clinical biomarkers in use today (CA 125, CA 15.3, CA 19.9, and PSA) were discovered through tissue culture-based system and tissue extracts. This paper tries to emphasize the tissue culture-based discovery of candidate biomarkers through various mass spectrometry-based proteomic approaches
Cisplatin Inhibits the Formation of a Reactive Intermediate during Copper-Catalyzed Oxidation of Amyloid β Peptide
Cisplatin was studied for its effect
on the copper-catalyzed oxidation of amyloid β (Aβ) peptide.
The interaction of cisplatin with Aβ1-16 in the presence of
Cu<sup>II</sup> was investigated using cyclic voltammetry and mass
spectrometry. The positive shift in the <i>E</i><sub>1/2</sub> value of Aβ1-16-Cu<sup>II</sup> suggests that the interaction
of cisplatin alters the copper-binding properties of Aβ1-16.
The mass spectrometry data show complete inhibition of copper-catalyzed
decarboxylation/deamination of the Asp1 residue of Aβ1-16, while
there is a significant decrease in copper-catalyzed oxidation of Aβ1-16
in the presence of cisplatin. Overall, our results provide a novel
mode by which cisplatin inhibits copper-catalyzed oxidation of Aβ.
These findings may lead to the design of better platinum complexes
to treat oxidative stress in Alzheimer’s disease and other
related neurological disorders
Protein Phosphatase 1 Regulatory Subunit SDS22 Inhibits Breast Cancer Cell Tumorigenesis by Functioning as a Negative Regulator of the AKT Signaling Pathway
Protein phosphatases play a crucial role in cell cycle progression, cell survival, cellular signaling, and genomic integrity. The protein phosphatase 1 (PP1) regulatory subunit SDS22 plays a significant role in cell cycle progression. A recent study showed that SDS22 plays a vital role in epithelial integrity and tumor suppression in Drosophila. However, its tumor suppressive activity remains obscure in the mammalian system. Here, for the first time, we show that SDS22 inhibits the growth of breast cancer cells through induction of apoptosis. SDS22 negatively regulates the AKT kinase signaling pathway through PP1. SDS22 associates predominantly with AKT and dephosphorylates the phospho Thr308 and phospho Ser473 through PP1 and hence abrogates the cell migration, invasion, and tumor growth. Thus, our study deciphers the long-standing question of how PP1 negatively regulates the AKT signaling pathway. Further, we observed a significant converse correlation in the expression levels of SDS22 and phospho form of AKT with reduced levels of SDS22 in the higher grades of cancer. Overall, our results suggest that SDS22 could be a putative tumor suppressor and replenishment of SDS22 would be an important strategy to restrict the tumor progression
Mass Spectral Studies Reveal the Structure of Aβ1–16–Cu<sup>2+</sup> Complex Resembling ATCUN Motif
In Alzheimer’s disease, copper binds to amyloid
beta (Aβ)
peptide and generates oxidative stress. The coordination of histidine
(His) residues to Cu<sup>2+</sup> is still uncertain. We studied Cu<sup>2+</sup> binding to Aβ1–16 peptide using the diethyl
pyrocarbonate (DEPC) assay and mass spectrometry. Our results show
that only one His is involved in Cu<sup>2+</sup> coordination, which
is identified as His6 using mass spectral studies. Novel nickel displacement
studies have further supported the proposal that the Cu<sup>2+</sup> binding site of Aβ1–16 peptide resembles the ATCUN
motif of human serum albumin
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