Browsing by Author "Biswa Pratim Das Purkayastha"

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Cancer cell metabolism and developmental homeodomain/POU domain transcription factors: A connecting link
(Elsevier Ireland Ltd, 2015) Biswa Pratim Das Purkayastha; Jagat Kumar Roy
The human race is afflicted with more than 100 types of cancer with diversified underlying genetic events. Still, altered metabolism (known as 'Warburg effect') and unrestrained cellular proliferation are precise traits of all cancers, being governed by the expression of genes. The obligatory energy for the proliferating neoplastic cells is endowed through the glycolytic pathway, albeit, lesser ATP is generated in this metabolic process. So, some perceptible cancer cell specific signalling is at the base of the transformed metabolism. Concurrently, the regulators of gene expression, transcription factors, have been observed to be one of the driving forces for tumourigenesis through transcriptional activation of genes involved not only in proliferation, growth and survival signalling, but also in glycolysis. This may be exemplified by the extensively studied metabolic functions of the transcriptional regulator, hypoxia inducible factor 1 (HIF1), which transactivates genes of the major enzymes of glycolysis. Preliminary investigation of a vital group of transcription factors, homeodomain transcription factors, revealed association with the process of development of an organism. The homeodomain transcription factors are, however, also found to be involved in the tumourigenesis process, with little or no information on their involvement in cancer cell metabolism. So, this is a review of the existing knowledge on homeodomain transcription factor/s for deciphering their involvement in neoplastic metabolism and it emerges that homeodomain transcription factors influence the transformed metabolic pathway in a circuitous manner. © 2014 Elsevier Ireland Ltd.
Enzymatic degradation of polylactide/layered silicate nanocomposites: Effect of organic modifiers
(2013) Narendra K. Singh; Biswa Pratim Das Purkayastha; Muktikanta Panigrahi; Rajeev K. Gautam; Rathindra M. Banik; Pralay Maiti
Biodegradable polylactide (PLA)/layered silicate nanocomposites have been prepared via solution route using two different kinds of organically modified nanoclays. The nanostructure as observed from wide-angle X-ray diffraction indicates intercalated hybrids and the extent of intercalation depends on the type of organic modifiers used. Melt-quenched PLA and its nanocomposites are predominantly amorphous but, after annealing, they are fairly crystalline. The nanohybrids show significant improvement in thermal properties as compared to neat polymer. The nature of interaction between nanoclays and matrix polymer depends on the organic modifiers used, as evident from varying heat of fusion and shifting of Fourier transform infrared peaks. The nanoclays act as nucleating agent, and thereby, control the spherulite dimension of the matrix. The comparison of biodegradation of PLA and its nanocomposites has been studied in enzyme, compost, and buffer solution. Biodegradability of PLA has significantly been enhanced in the presence of nanoclays and the rate varies on organic modifications. The surface morphology, before and after enzymatic degradation, confirms the relative rate of degradation through laser scanning confocal images, scanning electron microscope, and atomic force microscope. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 Copyright © 2012 Wiley Periodicals, Inc.
Molecular analysis of oncogenicity of the transcription factor, BRN3A, in cervical cancer cells
(2011) Biswa Pratim Das Purkayastha; Jagat Kumar Roy
Objective: The host cellular transcription factor, BRN3A, has been observed to play a vital role in cancer of the uterine cervix. BRN3A possesses multipartite functions, which include transcription of the genes of the high-risk HPVs and mediation of cellular changes in the host. In this study, we made an effort to decipher the regulation of BRN3A in cervical cancer cells by studying its interaction with different components of the cell. Methods: In cervical cancer cells, the endogenous HIPK2 was induced through cisplatin treatment, and then, its subsequent effect on BRN3A was primarily investigated through co-immunostaining and western blotting as HIPK2 has been observed to act as a co-repressor of Brn3a. The physical interaction of the two proteins was analyzed through co-immunoprecipitation. We resorted to chromatin immunoprecipitation in order to testify the autoregulatory pathway of BRN3A in cervical cancer cells. Interaction of BRN3A with cellular components, p73 and active form of JNK, was also studied through co-immunostaining. Results: We observed that BRN3A is independent of the regulative activity of HIPK2 and undergoes positive autoregulation in cervical cancer cells. Interestingly, during the study, it was revealed that BRN3A is unaffected by the treatment of cisplatin. Interaction of BRN3A with p73 and phosphorylated JNK in cervical cancer cells, observed in the present study, would help in understanding the molecular mechanism directed by BRN3A. Conclusions: BRN3A possesses anti-apoptotic property, and considering the above results, it may be regarded as the key component in promoting tumorigenic growth in the uterine cervical cells. © 2011 Springer-Verlag.
Nanoparticle controlled self-assembly in varying chain extended polyurethanes as potential nanobiomaterials
(2012) Abhinay Mishra; Biswa Pratim Das Purkayastha; Jagat K. Roy; Vinod K. Aswal; Pralay Maiti
Novel polyurethanes have been synthesized using aliphatic diisocyanate and aromatic chain extenders with varying spacer length. Nanohybrids of those polyurethanes have been prepared using two-dimensional surface modified nanoclay by dispersing it in poly-ol followed by prepolymerization and subsequent extension with chain extenders of a range of length scales. Dramatic improvement in toughness and adequate enhancement in stiffness in presence of nanoclay have been observed for higher spacer length of chain extender exhibiting no trade-off for these new classes of nanohybrids. Step-by-step self-assembly starting from nanometer dimension molecular association to micrometer scale crystallite has been revealed through electronic structure calculation, X-ray diffraction, small angle neutron scattering, atomic force microscopy, and optical images. The role of hydrogen bonding has been uncovered for this type of supramolecular assembly which further aggravated in presence of organically modified nanoclay by making bigger clusters for nanohybrids. The potential application for these nanohybrids as biomaterials has been verified through cell adhesion and cytotoxicity studies. Biocompatibility at the gene level was analyzed through the perspective of HIPK2, a member of the group involved in cell-cycle regulation. Sustained drug delivery has been testified by using bigger dimension of clusters formed by self-assembly. Another means of controlled drug delivery has been verified by dispersing disk-like two-dimensional nanoclay in polymer matrix by making diffusion barrier tortuous path. © 2011 American Chemical Society.
Nanostructure controlled anti-cancer drug delivery using poly(ε-caprolactone) based nanohybrids
(2012) Narendra K. Singh; Sunil K. Singh; Debabrata Dash; Biswa Pratim Das Purkayastha; Jagat K. Roy; Pralay Maiti
We have focused on the generation of various nanostructures of poly(ε-caprolactone) (PCL) using surface modified layered silicate. The improved and diverse mechanical, thermal and surface properties have been explored depending upon the nanostructure of the nanohybrids. The incorporation of drug into those nanohybrids further alters the nanostructure and subsequent properties. The rate of biodegradation has been studied in detail, with plausible mechanisms in different enzyme media being suggested, their specificity and the tunability of the biodegradation rate was demonstrated, followed by their optimization. The scaffolds of PCL and its nanohybrids with and without drugs have been prepared through electrospinning to control the dimensions of the nanofibers and their controlled degradation. The in-depth studies of the biocompatibility in terms of cell adhesion, genotoxicity and hemocompatibility have been performed to verify the suitability of the nanohybrids for potential biomedical applications. The biocompatibility of the nanohybrids at the gene level has been tested by the subcellular localization of an important regulator of pro-apoptotic signalling cascade, HIPK2 in human epithelial cells, demonstrating the attuned nature of the particles under study within the biological system. The blood compatibilities of the pure PCL and its nanohybrids were studied by platelet aggregation, platelet adhesion, and in vitro hemolysis assay, elucidating the excellent hemocompatibility of the novel nanohybrids. Biocompatible and hemocompatible nanohybrids have been testified for drug delivery and show sustained and controlled release of anti-cancer drugs (dexamethasone) in the presence of two dimensional disc-like nanoparticles. Hence, the developed nanohybrids are a potential biomaterial, suitable for tissue engineering and drug delivery. © 2012 The Royal Society of Chemistry.
Novel Variant Identified in the Enhancer Region of Host Transcription Factor, BRN3A, is a Significant Risk Factor for HPV-Induced Uterine Cervix Cancer
(Babol University of Medical Sciences, 2022) Anand Prakash; Biswa Pratim Das Purkayastha; Shikha Srivastava; Sunanda Chaturvedi; Akhtar Ali; Dau Dayal Aggarwal; Jagat Kumar Roy
Among the HPV-mediated cervical cancers, cellular factor BRN3A has gained considerable attention due to its role in promoting an anti-apoptotic cellular environment and in facilitating epitheliotropic transformations of the host. The majority of previous studies looked at BRN3A's molecular characteristics; however, the possibility of genetic variations in BRN3A's autoregulatory region in relation to cervical cancer risk has been underestimated until now. In a retrospective study in the Eastern UP population, India, we detected genetic variations in the cisregulatory proximal enhancer region located around 5.6 kb upstream of transcription start site of BRN3A. Our analysis of PCR and DNA sequencing confirmed this novel SNP (BRN3A g.60163379A>G) within the auto-regulatory region of BRN3A. As compared to control subjects, cancer cases exhibited a 1.32-fold higher allele frequency (χ2 = 6.315, p = 0.012). In homozygous (GG) but not in heterozygous conditions, odds ratio (OR) analysis suggests a significant association of cancer risk with the SNP (OR = 2.60, p ≤ 0.004). We further confirmed using the functional analysis that this SNP increased the luciferase gene activity in HPV-positive cervical cancer SiHa cells that were exposed to progesterone. As a result of the association of polymorphisms in a noncoding region of an oncogene with increased cancer risks, we are suggesting that this genetic variation in non-coding region can be used in prediction, diagnosis, or predicting the progression of the disease. © The Author(s).
Tunable properties of self-Assembled polyurethane using two-Dimensional nanoparticles: Potential nano-biohybrid
(2010) Abhinay Mishra; Biswa Pratim Das Purkayastha; Jagat K. Roy; Vinod K. Aswal; Pralay Maiti
Nanostructure, key to property alteration, has been widely diverse by using two-dimensional nanoparticle in different stages of polymerization. Molecular level self-assembly starting from nanoscale 2-D molecular sheet to optically observable microscale crystallite has been unraveled stepwise for thermoplastic elastomer for the first time. The nature of self-assembly can be tuned by judicious choice of polymerization procedure in the presence of organically modified nanoclay. The effect of modulated nanostructure and self-assembly has been explored for the unusual property enhancement including electronic, thermal, mechanical, barrier, and biological (genotoxicity). Both the stiffness and toughness increase in nano-biohybrid without any trade-off. The unique splintering phenomenon and its variation under a dynamic frequency have been investigated by changing the synthesizing route of nanohybrids using a fixed concentration of nanoparticle. For understanding the controlled cellular responses to the implant new hybrid materials, cell adhesion and detailed genotoxicity reveal total biological recognition of the developed nano-biohybrids. © 2010 American Chemical Society.
Tuned biodegradation using poly(hydroxybutyrate-co-valerate) nanobiohybrids: Emerging biomaterials for tissue engineering and drug delivery
(2011) Narendra K. Singh; Biswa Pratim Das Purkayastha; Jagat K. Roy; Rathindra M. Banik; Prasad Gonugunta; Manjusri Misra; Pralay Maiti
Our studies focus on controlled and tuned biodegradation, mechanism of biodegradation, biocompatibility, genotoxicity and controlled and sustained drug release performance of poly(hydroxybutyrate-co-valerate) nanohybrids. Nanohybrids were prepared using layered silicates with two different surface modifiers through a solution route. Biodegradation has been investigated in compost, microorganisms (pseudomonas stutzeri) and pure enzymes, showing both enhanced and suppressed rates as compared to that of the pure polymer. Two nanoclays that increased the strong filler dependency phenomena were used to control the biodegradation rate. Complete biodegradation mechanism has been revealed, which indicates that the pH of the medium dictates the rate of biodegradation by activating the enzyme responsible for degradation. Biodegradation has also been controlled by optimizing the processing conditions of the specimens. Biocompatibility of the nanohybrids has been tested at the intra-cellular level by sub-cellular localization of HIPK2 protein, in addition to the typical cell adherence on the nanohybrid films demonstrating that there is no induced genotoxic stress either from the polymer or from the nanoparticles. Biocompatible nanohybrids have been used for drug delivery, showing sustained and controlled release of drugs in presence of nanoparticles. Hence, the developed nanohybrids illustrate potential biomaterials for tissue engineering and drug delivery. © 2011 The Royal Society of Chemistry.