Publications by authors named "Bhabatosh Chaudhuri"

FK506-binding protein 2 (FKBP13) is a part of the immunophilin protein family involved in immunoregulation. It is also believed to operate as a factor in membrane cytoskeletal framework and as an ER chaperone. FKBP2 (FKBP13) and FKBP1 (FKBP12), known as immunophilins, are binding proteins for rapamycin and FK506, which are immunosuppressive drugs.

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Apoptosis is an essential process that is regulated genetically and could lead to a serious disease condition if not well controlled. Bax is one of the main proapoptotic proteins and actively involved in programmed cell death. It has been suggested that Bax induced apoptosis in yeast could be obstructed by enhancing vesicular membrane trafficking.

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Human α-synuclein expression in baker's yeast reportedly induces mitochondria-dependent apoptosis. Surprisingly, we find that, under de-repressing conditions of the inducible promoters, yeast cells expressing chromosomally-integrated copies of the human α-synuclein gene are not killed, but spontaneously form respiration-deficient rho-minus (ρ) petites. Although yeast cells can undergo cell death (apoptosis) from loss of mitochondrial function, they can also survive without functional mitochondria.

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Eukaryotic elongation factor 1A1 (eEF1A1) is central to translational activity. It is involved in complexes that form signal transduction with protein kinase C, as well as being a signal transducer and activator of transcription 3. eEF1A1 and eEF1A2 are isoforms of the alpha subunit of elongating factor 1 complex.

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Apoptosis is a form of programmed cell death which is essential for the growth of dividing human cells whereas, in contrast, it is deleterious for post-mitotic cells such as neurons. Bax and α-synuclein are two human proteins which play a role in the induction of neuronal apoptosis in neurodegenerative diseases like Alzheimer's and Parkinson's. Human Bax and α-synuclein also induce cell death when expressed in baker's yeast, Saccharomyces cerevisiae.

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Cytochrome P450 reductase (CPR) abstracts electrons from Nicotinamide adenine dinucleotide phosphate H (NADPH), transferring them to an active Cytochrome P450 (CYP) site to provide a functional CYP. In the present study, a yeast strain was genetically engineered to delete the endogenous CPR gene. A human CYP expressed in a CPR-null (yRD) strain was inactive.

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Different natural aromatic/heterocyclic l-amino acids were biotransformed into aryl/heteroaryl ethanol metabolites oxidative deamination, decarboxylation and reduction cascades using live baker's yeast cells producing intracellular human CYP2D6 enzyme. Among the three yeast strains expressing 3 different CYP2D6 variants, CYP2D6(2) ( CYP2D6 wild-type) provided the best result under neutral pH conditions at RT. We have successfully converted six natural amino acids into their corresponding alcohols, having one carbon atom less, with moderate yields.

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The overexpression of α-synuclein (α-syn) and its aggregation is the hallmark of Parkinson's disease. The α-syn aggregation results in the formation of Lewy bodies that causes neuronal cell death. Therefore, the small molecules that can protect neuronal cells from α-syn toxicity or inhibit the aggregation of α-syn could emerge as anti-Parkinson agents.

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CYP2D6, a cytochrome P450 (CYP) enzyme, metabolizes codeine to morphine. Within the human body, 0-15% of codeine undergoes O-demethylation by CYP2D6 to form morphine, a far stronger analgesic than codeine. Genetic polymorphisms in wild-type CYP2D6 (CYP2D6-wt) are known to cause poor-to-extensive metabolism of codeine and other CYP2D6 substrates.

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Cytochrome P450 family 1 (CYP1) enzymes catalyze the metabolic activation of environmental procarcinogens such as benzo[]pyrene, B[]P, into carcinogens, which initiates the process of carcinogenesis. Thus, stopping the metabolic activation of procarcinogens can possibly prevent the onset of cancer. Several natural products have been reported to show unique ability in inhibiting CYP1 enzymes.

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Microsomal cytochrome P450 (CYP) enzymes, isolated from recombinant bacterial/insect/yeast cells, are extensively used for drug metabolism studies. However, they may not always portray how a developmental drug would behave in human cells with intact intracellular transport mechanisms. This study emphasizes the usefulness of human HEK293 kidney cells, grown in 'suspension' for expression of CYPs, in finding potent CYP1A1/CYP1B1 inhibitors, as possible anticancer agents.

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Inhibition of cyclin dependent kinase 4 (Cdk4) prevents cancer cells from entering the early G/G phase of the cell division cycle whereas inhibiting tubulin polymerization blocks cancer cells' ability to undergo mitosis (M) late in the cell cycle. We had reported earlier that two non-planar and relatively non-toxic fascaplysin derivatives, an indole and a tryptoline, inhibit Cdk4 with IC values of 6.2 and 10 μM, respectively.

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Aggregation/misfolding of α-synuclein and βA4 proteins cause neuronal cell death (NCD) associated with Parkinson's and Alzheimer's disease. It has been suggested that a heat shock protein-90 (Hsp90) inhibitor can prevent NCD by activating the heat shock transcription factor-1 which, in turn, upregulates molecular chaperones such as Hsp70 that targets aggregated/misfolded proteins for refolding/degradation. We have isolated radicicol, an Hsp90 inhibitor, from a fungus occurring in the crevices of marble rocks of Central India.

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Herein, we have identified yeast Sec22p (ySec22p), a SNARE protein essential for endoplasmic reticulum to Golgi trafficking, as a suppressor of Bax-induced yeast apoptosis and corroborated published observations that ySec22p suppresses α-synuclein's toxicity in yeast. It has been suggested that compounds which enhance expression, in neurons, of human homologues of ySec22p (Sec22Bp/Sec22p/Sec22A) would prevent synucleinopathies, such as Parkinson's disease. With the aim of finding a small molecule that would mimic ySec22p, a library of natural products consisting of 394-compounds was screened using yeast cells that express either human α-synuclein or human Bax.

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Aggregated Aβ peptides which cause amyloid deposits, a characteristic of Alzheimer's disease (AD), activate a stress response in the endoplasmic reticulum (ER), known as the unfolded protein response, UPR. Nascent UPR induction helps in reducing ER stress by eliminating accumulated misfolded/aggregated secretory proteins. However, prolonged UPR induction may trigger apoptosis.

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Expression of cytochrome P450-1A1 (CYP1A1) is suppressed under physiologic conditions but is induced (a) by polycyclic aromatic hydrocarbons (PAHs) which can be metabolized by CYP1A1 to carcinogens, and (b) in majority of breast cancers. Hence, phytochemicals or dietary flavonoids, if identified as CYP1A1 inhibitors, may help in preventing PAH-mediated carcinogenesis and breast cancer. Herein, we have investigated the cancer chemopreventive potential of a flavonoid-rich Indian medicinal plant, Pongamia pinnata (L.

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CYP1A1 is thought to mediate carcinogenesis in oral, lung and epithelial cancers. In order to identify a CYP1A1 inhibitor from an edible plant, 394 natural products in the IIIM's natural product repository were screened, at 10 μM concentration, using CYP1A1-Sacchrosomes™ ( microsomal enzyme isolated from recombinant baker's yeast). Twenty-seven natural products were identified that inhibited 40-97% of CYP1A1's 7-ethoxyresorufin--deethylase activity.

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The development of multi-drug resistance to existing anticancer drugs is one of the major challenges in cancer treatment. The over-expression of cytochrome P450 1B1 enzyme has been reported to cause resistance to cisplatin. With an objective to discover cisplatin-resistance reversal agents, herein, we report the evaluation of Glycyrrhiza glabra (licorice) extracts and its twelve chemical constituents for inhibition of CYP1B1 (and CYP1A1) enzyme in Sacchrosomes and live human cells.

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The overexpression of CYP1 family of enzymes is reported to be associated with development of human carcinomas. It has been well reported that CYP1A1 specific inhibitors prevents carcinogenesis. Herein, thirteen pyridine-4-yl series of chalcones were synthesized and screened for inhibition of CYP1 isoforms 1A1, 1B1 and 1A2 in Sacchrosomes™ and live human HEK293 cells.

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Naturally occurring polyphenolic compounds are of medicinal importance because of their unique antioxidant, anticancer, and chemopreventive properties. Baicalein, a naturally occurring polyhydroxy flavonoid possessing a diverse range of pharmacological activities, has been used in traditional medicines for treatment of various ailments. Apart from its isolation from natural sources, its synthesis has been reported via multistep chemical approaches.

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Inhibitors of CYP1 enzymes may play vital roles in the prevention of cancer and overcoming chemo-resistance to anticancer drugs. In this letter, we report synthesis of twenty-three pyrrole based heterocyclic chalcones which were screened for inhibition of CYP1 isoforms. Compound 3n potently inhibited CYP1B1 with an IC of ∼0.

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Target structure-guided virtual screening (VS) is a versatile, powerful, and inexpensive alternative to experimental high-throughput screening (HTS). To discover potent CYP1A1 enzyme inhibitors for cancer chemoprevention, a commercial library of 50 000 small molecules was utilized for VS guided by both ligand and structure-based strategies. For experimental validation, 300 ligands were proposed based on combined analysis of fitness scores from ligand based e-pharmacophore screening and docking score, prime MMGB/SA binding affinity and interaction pattern analysis from structure-based VS.

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CYP1B1 is implicated to have a role in the development of breast, ovarian, renal, skin and lung carcinomas. It has been suggested that identification of potent and specific CYP1B1 inhibitors can lead to a novel treatment of cancer. Flavonoids have a compact rigid skeleton which fit precisely within the binding cavity of CYP1B1.

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