Background: The association of BAX-248 G>A and BCL2-938 C>A with different cancers created confli... more Background: The association of BAX-248 G>A and BCL2-938 C>A with different cancers created conflicts. We studied the correlation and the effect of these polymorphisms in patients with Nasopharyngeal Carcinoma (NPC). Methods: PCR-RFLP and Sanger sequencing were used to detect polymorphisms. Statistical analysis including forest plot and Kaplan-Meier Log-rank test was conducted to investigate the association and effect of these SNPs on the NPC patients' survival. The computational study was performed to investigate the possible regulatory role between these polymorphisms and the poor survival of NPC patients. Meta-analysis was executed to check the tissue-specific association of these polymorphisms in the context of global cancer prognosis. Results: We observed an increased and significant
Control of stage specific spike in ethylene production at anthesis has been a vauable route to po... more Control of stage specific spike in ethylene production at anthesis has been a vauable route to potentially enhance genetic ceiling for grain filling of rice spikelet. A number of genes controlling ethylene homeostasis and starch synthesis have been identified so long, but lack of credible information on master modulation of gene expression by miRNAs and their target genes associated with hormonal dynamics obfuscate mechanisms controlling genotype difference in quantum of grain filling. The confusion accounts for consequent shrinkage of options for yield manipulation. In a two by two factorial design, miRNA regulation of spikelet specific grain development in low against high sterile recombinant inbred lines of rice Oryza sativa L. namely CR 3856-62-11-3-1-1-1-1-1-1 (SR 157) and CR 3856-63-1-1-1-1-1-1-1 (SR 159) respectively, and inferior verses superior spikelets were compared during first 10 days after anthesis. Grain filling was poorer in SR159 than SR157 and inferior spikelets in...
Objectives Mannose-binding lectin (MBL), an essential innate immune molecule, enhances the opsoni... more Objectives Mannose-binding lectin (MBL), an essential innate immune molecule, enhances the opsonization process and activates the complement system. Genetic variations at the promoter and coding region of the MBL-2 gene have been associated with susceptibility to systemic lupus erythematosus (SLE); however, reports remained inconsistent. The present study performs a meta-analysis of published peer-reviewed articles to draw a definitive conclusion. Materials and Methods Published peer-reviewed articles on the association of MBL-2 gene polymorphisms and SLE were screened on various databases such as PubMed (Medline), ScienceDirect, and Google Scholar. A total of 23 eligible articles were included in the present study, comprising 3074 SLE patients and 3985 controls. Genotype and/or allele data for MBL-2 polymorphisms (A > B, A > C, A > D, A > O, Y > X and H > L) were extracted and analyzed by Comprehensive Meta-Analysis software (CMA V3.1). Results The overall analysi...
Nasopharyngeal carcinoma (NPC) is a rare malignancy in most parts of the world, but is endemic in... more Nasopharyngeal carcinoma (NPC) is a rare malignancy in most parts of the world, but is endemic in some ethnic groups. The association of NPC with the Epstein-Barr virus (EBV) is firmly established; however, the mechanism is still unclear. TLR9 is well known for its essential role in viral pathogen recognition and activation of innate immunity. Here, we report a set of TLR9 polymorphisms in the TIR-2 domain of the TLR9 protein collected from the EBV-infected NPC samples from northeast Indian populations sharing the aforesaid ethnicity. The occurrence of mutations is significantly high in these samples as we found a p value of <0.0001 at a significance level of 0.05. These might play an important role for the lack of function of TLR9 and thus for the higher occurrence of EBV-mediated NPC in such ethnic groups.
Nasopharyngeal carcinoma (NPC) is one the most confusing and rare malignancy in most part of the ... more Nasopharyngeal carcinoma (NPC) is one the most confusing and rare malignancy in most part of the world with significantly high occurrence in some populations of Southeast Asia, North Africa and Alaska. Apart from the dietary and environmental factors, NPC is well‐associated with Epstein‐Barr virus (EBV) infection in these ethnic groups. However, the internal molecular mechanism(s) for such association in specific populations is not known till date. Polymorphisms in the genes of histocompatibility locus antigens (HLA) are reported in NPC, but association of any particular polymorphism with ethnicity is not established yet. Here, we report a set of HLA polymorphisms in EBV‐infected NPC samples from Northeast Indian population. These polymorphisms might play an important role for the lack of proper immune function against EBV infection and thus, eventually, for NPC generation in endemic populations like those of Northeast India.
Interleukin-28B (IL28B) locus on a human chromosomal region 19q13 is responsible for immune prote... more Interleukin-28B (IL28B) locus on a human chromosomal region 19q13 is responsible for immune protection against viruses. IL28B in hepatitis C virus (HCV) infection determines the fate of infection towards causing spontaneous clearance or chronic liver infection. Choice of treatment in chronic hepatitis C infection includes use of direct acting antivirals, pegylated-interferon (PEG-IFN) or ribavirin (RBV) therapy. Interferon free regimens are also suggested to be useful in drug resistant patients. Genome-wide association studies (GWAS), comprehensive meta-analysis and independent case-control studies in different ethnic populations have demonstrated association between certain Il-28B polymorphisms and its effect on the response to PEG-IFN-RBV therapy in HCV patients. .Further, IL28B SNPs and its association with the SVR rate in HCV patients on PEG-IFN-RBV therapy is well documented. Thus, IL28B genotyping may be used as a predictor of IFN-based therapy outcomes, and a strategy for dev...
Kaposi's sarcoma associated herpesvirus (KSHV) a gammaherpesvirus establishes perennial latency i... more Kaposi's sarcoma associated herpesvirus (KSHV) a gammaherpesvirus establishes perennial latency in the host with periodic reactivation. Occasionally change in the physiological condition like hypoxia, host cell differentiation can trigger the lytic switch and reactivation of the virus. The biologically active form of 1, 25(OH)2 D3 plays a critical role in the regulation of various physiological processes (e.g. regulation of mineral homeostasis and control of bone metabolism). Apart from its role in host physiology, 1, 25(OH)2 D3 has been implicated as a potential agent for the prevention and/or treatment of many a tumors. Here we show that 1, 25(OH)2 D3 induces both death of Kaposi sarcoma associated herpesvirus infected PEL cells and KSHV replication. 1, 25(OH)2 D3 mediated inhibition of proliferation was associated with apoptosis of the PEL cells, and virus reactivation. In addition, p38 signalling is required for KSHV reactivation. Furthermore, treatment of PEL cells with p38 inhibitor abrogated the expression of ORF57, thus blocking lytic switch. Furthermore, silencing of VDR resulted in reduced ORF57 expression compared to the control cells, signifying the potential role of 1, 25(OH)2 D3 in KSHV reactivation. Thus, our studies have revealed a novel role of 1, 25(OH)2 D3 in the regulation of KSHV reactivation and PEL cell death. Kaposi's sarcoma associated herpesvirus (KSHV) is a DNA tumor viruses belonging to a member of gammaherpesvirus family and is associated with Kaposi sarcoma (KS), Primary effusion lymphoma (PEL) and a subtype of multicentric castleman disease (MCD) 1-4. KSHV like other herpesvirus exhibits two different life cycles, latent and lytic. During latent infection, only a subset of genes are expressed, which enable KSHV to evade immune system and promote viral persistence 5-7. While lytic cycle, lytic proteins are expressed in an ordered cascade to produce virons for their efficient propagation and transmission 8,9. Studying induction of lytic switch provides an opportunity to understand the infection and pathogenesis of KSHV associated diseases. The switch from latent to lytic replication is an active area of research and has contributed to a large extent information about the cellular factors with possible roles in reactivation mechanisms. However the regulation of KSHV pathogenesis by metabolic pathways is still only sparsely understood. Primary effusion lymphoma (PEL) is a rare HIV-associated non-Hodgkin's lymphoma (NHL), resembles a transformed post-germinal center (GC) B cell 10-12. PEL typically presents with lymphomatous body cavity effusions in the absence of solid tumor masses harbouring KSHV episomes and arise preferentially within the pleural or peritoneal cavities of approximately 4% of all HIV associated NHLs 13-15. KSHV infection of PEL cell is predominantly latent, which makes PEL cells an ideal cell lines to study two phases of its life cycle 16. Therapeutic induction of virus replication is necessary to target and eliminate KSHV associated tumor cells. Earlier studies have attempted induction of KSHV reactivation with a different compounds or drugs 17-19. Vitamin D3 was originally identified as a key regulator of bone metabolism and calcium homeostasis 20. Most of the biological action of 1, 25(OH)2 D3 are exerted through nuclear receptor vitamin D receptor (VDR) 21. Apart from bone metabolism and calcium homeostasis, 1, 25(OH)2 D3 has been shown to be involved in the control
Apoptosis : an international journal on programmed cell death, Jan 26, 2017
Kaposi's sarcoma associated herpes virus (KSHV) infected primary effusion lymphoma (PEL) is a... more Kaposi's sarcoma associated herpes virus (KSHV) infected primary effusion lymphoma (PEL) is a rare aggressive form of non-Hodgkin's lymphoma of B cells. KSHV latent and lytic antigens modulate several host cellular signalling pathways especially mammalian target of rapamycin (mTOR), STAT-3 and nuclear factor-kappa B (NF-κB) for rapid tumor progression and immune evasion. Current chemotherapeutic strategies are becoming ineffective as they kill only dividing cells and inefficient to target molecular pathways crucial for active virus replication and its survival. In this study, we evaluated the efficacy of everolimus, an mTOR inhibitor in inducing apoptosis of PEL cells. Dose-dependent treatment of everolimus triggered mitochondria-mediated caspase-dependent apoptosis in PEL cells. Everolimus downregulated KSHV latent antigen expression with concurrent blocking of lytic reactivation for active virus replication. Everolimus also inhibited latent antigen mediated constitutively ...
The rapid decrease in fossil reserves has significantly increased the demand of renewable and sus... more The rapid decrease in fossil reserves has significantly increased the demand of renewable and sustainable energy fuel resources. Fluctuating fuel prices and significant greenhouse gas (GHG) emission levels have been key impediments associated with the production and utilization of nonrenewable fossil fuels. This has resulted in escalating interests to develop new and improve inexpensive carbon neutral energy technologies to meet future demands. Various process options to produce a variety of biofuels including biodiesel, bioethanol, biohydrogen, bio-oil, and biogas have been explored as an alternative to fossil fuels. The renewable, biodegradable, and nontoxic nature of biofuels make them appealing as alternative fuels. Biofuels can be produced from various renewable resources. Among these renewable resources, algae appear to be promising in delivering sustainable energy options. Algae have a high carbon dioxide (CO2) capturing efficiency, rapid growth rate, high biomass productivity, and the ability to grow in non-potable water. For algal biomass, the two main conversion pathways used to produce biofuel include biochemical and thermochemical conversions. Algal biofuel production is, however, challenged with process scalability for high conversion rates and high energy demands for biomass harvesting. This affects the viable achievement of industrial-scale bioprocess conversion under optimum economy. Although algal biofuels have the potential to provide a sustainable fuel for future, active research aimed at improving upstream and downstream technologies is critical. New technologies and improved systems focused on photobioreactor design, cultivation optimization, culture dewatering, and biofuel production are required to minimize the drawbacks associated with existing methods. Nanotechnology has the potential to address some of the upstream and downstream challenges associated with the development of algal biofuels. It can be applied to improve system design, cultivation, dewatering, biomass characterization, and biofuel conversion. This chapter discusses thermochemical conversion of microalgal biomass with recent advances in the application of nanotechnology to enhance the development of biofuels from algae. Nanotechnology has proven to improve the performance of existing technologies used in thermochemical treatment and conversion of biomass. The different bioprocess aspects, such as reactor design and operation, analytical techniques, and experimental validation of kinetic studies, to provide insights into the application of nanotechnology for enhanced algal biofuel production are addressed.
Studies have suggested that Epithelial-Mesenchymal Transition (EMT) and transformation is an impo... more Studies have suggested that Epithelial-Mesenchymal Transition (EMT) and transformation is an important step in progression to cancer. Par3 (partitioning-defective protein) is a crucial factor in regulating epithelial cell polarity. However, the mechanism by which the latency associated nuclear antigen (LANA) encoded by Kaposi's Sarcoma associated herpesvirus (KSHV) regulates Par3 and EMTs markers (Epithelial-Mesenchymal Transition) during viral-mediated B-cell oncogenesis has not been fully explored. Moreover, several studies have demonstrated a crucial role for EMT markers during B-cell malignancies. In this study, we demonstrate that Par3 is significantly up-regulated in KSHV-infected primary B-cells. Further, Par3 interacted with LANA in KSHV positive and LANA expressing cells which led to translocation of Par3 from the cell periphery to a predominantly nuclear signal. Par3 knockdown led to reduced cell proliferation and increased apoptotic induction. Levels of SNAIL was elevated, and E-cadherin was reduced in the presence of LANA or Par3. Interestingly, KSHV infection in primary B-cells led to enhancement of SNAIL and down-regulation of E-cadherin in a temporal manner. Importantly, knockdown of SNAIL, a major EMT regulator, in KSHV cells resulted in reduced expression of LANA, Par3, and enhanced Ecadherin. Also, SNAIL bound to the promoter region of p21 and can regulate its activity. Further a SNAIL inhibitor diminished NF-kB signaling through upregulation of Caspase3 in KSHV positive cells in vitro. This was also supported by upregulation of SNAIL and Par3 in BC-3 transplanted NOD-SCID mice which has potential as a therapeutic target for KSHVassociated B-cell lymphomas.
Tumor suppressor p53 is a critical player in the fight against cancer as it controls the cell cyc... more Tumor suppressor p53 is a critical player in the fight against cancer as it controls the cell cycle check point, apoptotic pathways and genomic stability. It is known to be the most frequently mutated gene in a wide variety of human cancers. Single-nucleotide polymorphism of p53 at codon72 leading to substitution of proline (Pro) in place of arginine (Arg) has been identified as a risk factor for development of many cancers, including nasopharyngeal carcinoma (NPC). However, the association of this polymorphism with NPC across the published literature has shown conflicting results. We aimed to conduct a case–control study for a possible relation of p53 codon72 Arg>Pro polymorphism with NPC risk in underdeveloped states of India, combine the result with previously available records from different databases and perform a meta-analysis to draw a more definitive conclusion. A total of 70 NPC patients and 70 healthy controls were enrolled from different hospitals of north-eastern Indi...
Kaposi's sarcoma-associated herpesvirus (KSHV) infects a variety of human cells including cells o... more Kaposi's sarcoma-associated herpesvirus (KSHV) infects a variety of human cells including cells of epithelial, mesenchymal and endothelial origin. The latency associated nuclear antigen (LANA) of this virus regulates the transcription of a number of viral and cellular genes essential for the survival of the virus in the host cell. TAp63α can induce apoptosis in stressed cells by upregulating various death receptors and loss of mitochondrial membrane potential. The present study demonstrates that LANA inhibits TAp63α-mediated apoptosis by a direct interaction with each other. This interaction also results in a reduction in loss of mitochondrial membrane potential caused by TAp63α. Therefore the present study indicates a possible mechanism of KSHV-infected cells to escape apoptosis and facilitate survival.
The Kaposi's sarcoma-associated herpesvirus infects the human population and maintains latency st... more The Kaposi's sarcoma-associated herpesvirus infects the human population and maintains latency stage of viral life cycle in a variety of cell types including cells of epithelial, mesenchymal and endothelial origin. The establishment of latent infection by KSHV requires the expression of an unique repertoire of genes among which latency associated nuclear antigen (LANA) plays a critical role in the replication of the viral genome. LANA regulates the transcription of a number of viral and cellular genes essential for the survival of the virus in the host cell. The present study demonstrates the disruption of the host G2/M cell cycle checkpoint regulation as an associated function of LANA. DNA profile of LANA expressing human B-cells demonstrated the ability of this nuclear antigen in relieving the drug (Nocodazole) induced G2/M checkpoint arrest. Caffeine suppressed nocodazole induced G2/M arrest indicating involvement of the ATM/ATR. Notably, we have also shown the direct interaction of LANA with Chk2, the ATM/ATR signalling effector and is responsible for the release of the G2/M cell cycle block.
ABSTRACTEpstein-Barr virus (EBV) was the first human DNA virus to be associated with cancer. Its ... more ABSTRACTEpstein-Barr virus (EBV) was the first human DNA virus to be associated with cancer. Its oncogenic potential was further demonstrated by its ability to transform primary B lymphocytes in vitro. EBV nuclear antigen 3C (EBNA3C) is one of a small subset of latent antigens critical for the transformation of human primary B lymphocytes. Although EBNA3C has been shown to modulate several cellular functions, additional targets involved in cellular transformation remain to be explored. EBNA3C can recruit key components of the SCFSkp2ubiquitin ligase complex. In this report, we show that EBNA3C residues 130 to 190, previously shown to bind to the SCFSkp2complex, also can strongly associate with the c-Myc oncoprotein. Additionally, the interaction of EBNA3C with c-Myc was mapped to the region of c-Myc that includes the highly conserved Skp2 binding domain. Skp2 has been shown to regulate c-Myc stability and also has been shown to function as a coactivator of transcription for c-Myc ta...
The small molecule Quinacrine (QC, a derivative of 9‐aminoacridine), an anti‐malaria drug, displa... more The small molecule Quinacrine (QC, a derivative of 9‐aminoacridine), an anti‐malaria drug, displays activity against cancer cell lines and can simultaneously suppress nuclear factor‐κB (NF‐κB) and activate p53 signaling. In this study, we investigated the anticancer mechanism underlying these drug activities in breast cancer cell lines. QC caused a dose‐dependent decrease of both anchorage dependent and independent growth of breast cancer cells (MCF‐7 and MDA‐MB‐231) without affecting normal breast epithelial cells (MCF‐10A), as evident from clonogenic cell survival, [3‐(4,5‐dimethylthiazol‐2yl‐)‐2,5‐diphenyl tetrazolium bromide] viability, wound healing and soft agar growth. QC activated the proapoptotic marker Bax, PARP cleavage, p53 and its downstream target, p21 (Cip1/Waf1) and downregulated the antiapoptotic marker Bcl‐xL and relative luciferase activity of NF‐κB in MCF‐7 cells. Results of DAPI nuclear staining and FACS analysis show that QC increased apoptosis in a dose‐depend...
Nm23-H1 is a well-known tumor metastasis suppressor, which functions as a nucleosidediphosphate k... more Nm23-H1 is a well-known tumor metastasis suppressor, which functions as a nucleosidediphosphate kinase converting nucleoside diphosphates to nucleoside triphosphates with an expense of ATP. It regulates a variety of cellular activities, including proliferation, development, migration and differentiation known to be modulated by a series of complex signaling pathway. Few studies have addressed the mechanistic action of Nm23-H1 in the context of these cellular processes. To determine the downstream pathways modulated by Nm23-H1, we expressed Nm23-H1 in a Burkitt lymphoma derived B-cell line BJAB and performed pathway specific microarray analysis. The genes with significant changes in expression patterns were clustered in groups which are responsible for regulating cell cycle, p53 activities and apoptosis. We found a general reduction of cell cycle regulatory proteins including cyclins and cyclin dependent kinase inhibitors (anti proliferation), and upregulation of apoptotic genes which included caspase 3, 9 and Bcl-x. Nm23-H1 was also found to upregulate p53 and downregulate p21 expression. A number of these genes were validated by real time PCR and results from promoter assays indicated that Nm23-H1 expression downregulated cyclin D1 in a dose responsive manner. Further, we show that Nm23-H1 forms a complex with the cellular transcription factor AP1 to modulate cyclin D1 expression levels. BJAB cells expressing Nm23-H1 showed reduced proliferation rate and were susceptible to increased apoptosis which may in part be due to a direct interaction between Nm23-H1 and p53. These results suggest that Nm23-H1 may have a role in the regulation of cell cycle and apoptosis in human B-cells.
Background: The association of BAX-248 G>A and BCL2-938 C>A with different cancers created confli... more Background: The association of BAX-248 G>A and BCL2-938 C>A with different cancers created conflicts. We studied the correlation and the effect of these polymorphisms in patients with Nasopharyngeal Carcinoma (NPC). Methods: PCR-RFLP and Sanger sequencing were used to detect polymorphisms. Statistical analysis including forest plot and Kaplan-Meier Log-rank test was conducted to investigate the association and effect of these SNPs on the NPC patients' survival. The computational study was performed to investigate the possible regulatory role between these polymorphisms and the poor survival of NPC patients. Meta-analysis was executed to check the tissue-specific association of these polymorphisms in the context of global cancer prognosis. Results: We observed an increased and significant
Control of stage specific spike in ethylene production at anthesis has been a vauable route to po... more Control of stage specific spike in ethylene production at anthesis has been a vauable route to potentially enhance genetic ceiling for grain filling of rice spikelet. A number of genes controlling ethylene homeostasis and starch synthesis have been identified so long, but lack of credible information on master modulation of gene expression by miRNAs and their target genes associated with hormonal dynamics obfuscate mechanisms controlling genotype difference in quantum of grain filling. The confusion accounts for consequent shrinkage of options for yield manipulation. In a two by two factorial design, miRNA regulation of spikelet specific grain development in low against high sterile recombinant inbred lines of rice Oryza sativa L. namely CR 3856-62-11-3-1-1-1-1-1-1 (SR 157) and CR 3856-63-1-1-1-1-1-1-1 (SR 159) respectively, and inferior verses superior spikelets were compared during first 10 days after anthesis. Grain filling was poorer in SR159 than SR157 and inferior spikelets in...
Objectives Mannose-binding lectin (MBL), an essential innate immune molecule, enhances the opsoni... more Objectives Mannose-binding lectin (MBL), an essential innate immune molecule, enhances the opsonization process and activates the complement system. Genetic variations at the promoter and coding region of the MBL-2 gene have been associated with susceptibility to systemic lupus erythematosus (SLE); however, reports remained inconsistent. The present study performs a meta-analysis of published peer-reviewed articles to draw a definitive conclusion. Materials and Methods Published peer-reviewed articles on the association of MBL-2 gene polymorphisms and SLE were screened on various databases such as PubMed (Medline), ScienceDirect, and Google Scholar. A total of 23 eligible articles were included in the present study, comprising 3074 SLE patients and 3985 controls. Genotype and/or allele data for MBL-2 polymorphisms (A > B, A > C, A > D, A > O, Y > X and H > L) were extracted and analyzed by Comprehensive Meta-Analysis software (CMA V3.1). Results The overall analysi...
Nasopharyngeal carcinoma (NPC) is a rare malignancy in most parts of the world, but is endemic in... more Nasopharyngeal carcinoma (NPC) is a rare malignancy in most parts of the world, but is endemic in some ethnic groups. The association of NPC with the Epstein-Barr virus (EBV) is firmly established; however, the mechanism is still unclear. TLR9 is well known for its essential role in viral pathogen recognition and activation of innate immunity. Here, we report a set of TLR9 polymorphisms in the TIR-2 domain of the TLR9 protein collected from the EBV-infected NPC samples from northeast Indian populations sharing the aforesaid ethnicity. The occurrence of mutations is significantly high in these samples as we found a p value of <0.0001 at a significance level of 0.05. These might play an important role for the lack of function of TLR9 and thus for the higher occurrence of EBV-mediated NPC in such ethnic groups.
Nasopharyngeal carcinoma (NPC) is one the most confusing and rare malignancy in most part of the ... more Nasopharyngeal carcinoma (NPC) is one the most confusing and rare malignancy in most part of the world with significantly high occurrence in some populations of Southeast Asia, North Africa and Alaska. Apart from the dietary and environmental factors, NPC is well‐associated with Epstein‐Barr virus (EBV) infection in these ethnic groups. However, the internal molecular mechanism(s) for such association in specific populations is not known till date. Polymorphisms in the genes of histocompatibility locus antigens (HLA) are reported in NPC, but association of any particular polymorphism with ethnicity is not established yet. Here, we report a set of HLA polymorphisms in EBV‐infected NPC samples from Northeast Indian population. These polymorphisms might play an important role for the lack of proper immune function against EBV infection and thus, eventually, for NPC generation in endemic populations like those of Northeast India.
Interleukin-28B (IL28B) locus on a human chromosomal region 19q13 is responsible for immune prote... more Interleukin-28B (IL28B) locus on a human chromosomal region 19q13 is responsible for immune protection against viruses. IL28B in hepatitis C virus (HCV) infection determines the fate of infection towards causing spontaneous clearance or chronic liver infection. Choice of treatment in chronic hepatitis C infection includes use of direct acting antivirals, pegylated-interferon (PEG-IFN) or ribavirin (RBV) therapy. Interferon free regimens are also suggested to be useful in drug resistant patients. Genome-wide association studies (GWAS), comprehensive meta-analysis and independent case-control studies in different ethnic populations have demonstrated association between certain Il-28B polymorphisms and its effect on the response to PEG-IFN-RBV therapy in HCV patients. .Further, IL28B SNPs and its association with the SVR rate in HCV patients on PEG-IFN-RBV therapy is well documented. Thus, IL28B genotyping may be used as a predictor of IFN-based therapy outcomes, and a strategy for dev...
Kaposi's sarcoma associated herpesvirus (KSHV) a gammaherpesvirus establishes perennial latency i... more Kaposi's sarcoma associated herpesvirus (KSHV) a gammaherpesvirus establishes perennial latency in the host with periodic reactivation. Occasionally change in the physiological condition like hypoxia, host cell differentiation can trigger the lytic switch and reactivation of the virus. The biologically active form of 1, 25(OH)2 D3 plays a critical role in the regulation of various physiological processes (e.g. regulation of mineral homeostasis and control of bone metabolism). Apart from its role in host physiology, 1, 25(OH)2 D3 has been implicated as a potential agent for the prevention and/or treatment of many a tumors. Here we show that 1, 25(OH)2 D3 induces both death of Kaposi sarcoma associated herpesvirus infected PEL cells and KSHV replication. 1, 25(OH)2 D3 mediated inhibition of proliferation was associated with apoptosis of the PEL cells, and virus reactivation. In addition, p38 signalling is required for KSHV reactivation. Furthermore, treatment of PEL cells with p38 inhibitor abrogated the expression of ORF57, thus blocking lytic switch. Furthermore, silencing of VDR resulted in reduced ORF57 expression compared to the control cells, signifying the potential role of 1, 25(OH)2 D3 in KSHV reactivation. Thus, our studies have revealed a novel role of 1, 25(OH)2 D3 in the regulation of KSHV reactivation and PEL cell death. Kaposi's sarcoma associated herpesvirus (KSHV) is a DNA tumor viruses belonging to a member of gammaherpesvirus family and is associated with Kaposi sarcoma (KS), Primary effusion lymphoma (PEL) and a subtype of multicentric castleman disease (MCD) 1-4. KSHV like other herpesvirus exhibits two different life cycles, latent and lytic. During latent infection, only a subset of genes are expressed, which enable KSHV to evade immune system and promote viral persistence 5-7. While lytic cycle, lytic proteins are expressed in an ordered cascade to produce virons for their efficient propagation and transmission 8,9. Studying induction of lytic switch provides an opportunity to understand the infection and pathogenesis of KSHV associated diseases. The switch from latent to lytic replication is an active area of research and has contributed to a large extent information about the cellular factors with possible roles in reactivation mechanisms. However the regulation of KSHV pathogenesis by metabolic pathways is still only sparsely understood. Primary effusion lymphoma (PEL) is a rare HIV-associated non-Hodgkin's lymphoma (NHL), resembles a transformed post-germinal center (GC) B cell 10-12. PEL typically presents with lymphomatous body cavity effusions in the absence of solid tumor masses harbouring KSHV episomes and arise preferentially within the pleural or peritoneal cavities of approximately 4% of all HIV associated NHLs 13-15. KSHV infection of PEL cell is predominantly latent, which makes PEL cells an ideal cell lines to study two phases of its life cycle 16. Therapeutic induction of virus replication is necessary to target and eliminate KSHV associated tumor cells. Earlier studies have attempted induction of KSHV reactivation with a different compounds or drugs 17-19. Vitamin D3 was originally identified as a key regulator of bone metabolism and calcium homeostasis 20. Most of the biological action of 1, 25(OH)2 D3 are exerted through nuclear receptor vitamin D receptor (VDR) 21. Apart from bone metabolism and calcium homeostasis, 1, 25(OH)2 D3 has been shown to be involved in the control
Apoptosis : an international journal on programmed cell death, Jan 26, 2017
Kaposi's sarcoma associated herpes virus (KSHV) infected primary effusion lymphoma (PEL) is a... more Kaposi's sarcoma associated herpes virus (KSHV) infected primary effusion lymphoma (PEL) is a rare aggressive form of non-Hodgkin's lymphoma of B cells. KSHV latent and lytic antigens modulate several host cellular signalling pathways especially mammalian target of rapamycin (mTOR), STAT-3 and nuclear factor-kappa B (NF-κB) for rapid tumor progression and immune evasion. Current chemotherapeutic strategies are becoming ineffective as they kill only dividing cells and inefficient to target molecular pathways crucial for active virus replication and its survival. In this study, we evaluated the efficacy of everolimus, an mTOR inhibitor in inducing apoptosis of PEL cells. Dose-dependent treatment of everolimus triggered mitochondria-mediated caspase-dependent apoptosis in PEL cells. Everolimus downregulated KSHV latent antigen expression with concurrent blocking of lytic reactivation for active virus replication. Everolimus also inhibited latent antigen mediated constitutively ...
The rapid decrease in fossil reserves has significantly increased the demand of renewable and sus... more The rapid decrease in fossil reserves has significantly increased the demand of renewable and sustainable energy fuel resources. Fluctuating fuel prices and significant greenhouse gas (GHG) emission levels have been key impediments associated with the production and utilization of nonrenewable fossil fuels. This has resulted in escalating interests to develop new and improve inexpensive carbon neutral energy technologies to meet future demands. Various process options to produce a variety of biofuels including biodiesel, bioethanol, biohydrogen, bio-oil, and biogas have been explored as an alternative to fossil fuels. The renewable, biodegradable, and nontoxic nature of biofuels make them appealing as alternative fuels. Biofuels can be produced from various renewable resources. Among these renewable resources, algae appear to be promising in delivering sustainable energy options. Algae have a high carbon dioxide (CO2) capturing efficiency, rapid growth rate, high biomass productivity, and the ability to grow in non-potable water. For algal biomass, the two main conversion pathways used to produce biofuel include biochemical and thermochemical conversions. Algal biofuel production is, however, challenged with process scalability for high conversion rates and high energy demands for biomass harvesting. This affects the viable achievement of industrial-scale bioprocess conversion under optimum economy. Although algal biofuels have the potential to provide a sustainable fuel for future, active research aimed at improving upstream and downstream technologies is critical. New technologies and improved systems focused on photobioreactor design, cultivation optimization, culture dewatering, and biofuel production are required to minimize the drawbacks associated with existing methods. Nanotechnology has the potential to address some of the upstream and downstream challenges associated with the development of algal biofuels. It can be applied to improve system design, cultivation, dewatering, biomass characterization, and biofuel conversion. This chapter discusses thermochemical conversion of microalgal biomass with recent advances in the application of nanotechnology to enhance the development of biofuels from algae. Nanotechnology has proven to improve the performance of existing technologies used in thermochemical treatment and conversion of biomass. The different bioprocess aspects, such as reactor design and operation, analytical techniques, and experimental validation of kinetic studies, to provide insights into the application of nanotechnology for enhanced algal biofuel production are addressed.
Studies have suggested that Epithelial-Mesenchymal Transition (EMT) and transformation is an impo... more Studies have suggested that Epithelial-Mesenchymal Transition (EMT) and transformation is an important step in progression to cancer. Par3 (partitioning-defective protein) is a crucial factor in regulating epithelial cell polarity. However, the mechanism by which the latency associated nuclear antigen (LANA) encoded by Kaposi's Sarcoma associated herpesvirus (KSHV) regulates Par3 and EMTs markers (Epithelial-Mesenchymal Transition) during viral-mediated B-cell oncogenesis has not been fully explored. Moreover, several studies have demonstrated a crucial role for EMT markers during B-cell malignancies. In this study, we demonstrate that Par3 is significantly up-regulated in KSHV-infected primary B-cells. Further, Par3 interacted with LANA in KSHV positive and LANA expressing cells which led to translocation of Par3 from the cell periphery to a predominantly nuclear signal. Par3 knockdown led to reduced cell proliferation and increased apoptotic induction. Levels of SNAIL was elevated, and E-cadherin was reduced in the presence of LANA or Par3. Interestingly, KSHV infection in primary B-cells led to enhancement of SNAIL and down-regulation of E-cadherin in a temporal manner. Importantly, knockdown of SNAIL, a major EMT regulator, in KSHV cells resulted in reduced expression of LANA, Par3, and enhanced Ecadherin. Also, SNAIL bound to the promoter region of p21 and can regulate its activity. Further a SNAIL inhibitor diminished NF-kB signaling through upregulation of Caspase3 in KSHV positive cells in vitro. This was also supported by upregulation of SNAIL and Par3 in BC-3 transplanted NOD-SCID mice which has potential as a therapeutic target for KSHVassociated B-cell lymphomas.
Tumor suppressor p53 is a critical player in the fight against cancer as it controls the cell cyc... more Tumor suppressor p53 is a critical player in the fight against cancer as it controls the cell cycle check point, apoptotic pathways and genomic stability. It is known to be the most frequently mutated gene in a wide variety of human cancers. Single-nucleotide polymorphism of p53 at codon72 leading to substitution of proline (Pro) in place of arginine (Arg) has been identified as a risk factor for development of many cancers, including nasopharyngeal carcinoma (NPC). However, the association of this polymorphism with NPC across the published literature has shown conflicting results. We aimed to conduct a case–control study for a possible relation of p53 codon72 Arg>Pro polymorphism with NPC risk in underdeveloped states of India, combine the result with previously available records from different databases and perform a meta-analysis to draw a more definitive conclusion. A total of 70 NPC patients and 70 healthy controls were enrolled from different hospitals of north-eastern Indi...
Kaposi's sarcoma-associated herpesvirus (KSHV) infects a variety of human cells including cells o... more Kaposi's sarcoma-associated herpesvirus (KSHV) infects a variety of human cells including cells of epithelial, mesenchymal and endothelial origin. The latency associated nuclear antigen (LANA) of this virus regulates the transcription of a number of viral and cellular genes essential for the survival of the virus in the host cell. TAp63α can induce apoptosis in stressed cells by upregulating various death receptors and loss of mitochondrial membrane potential. The present study demonstrates that LANA inhibits TAp63α-mediated apoptosis by a direct interaction with each other. This interaction also results in a reduction in loss of mitochondrial membrane potential caused by TAp63α. Therefore the present study indicates a possible mechanism of KSHV-infected cells to escape apoptosis and facilitate survival.
The Kaposi's sarcoma-associated herpesvirus infects the human population and maintains latency st... more The Kaposi's sarcoma-associated herpesvirus infects the human population and maintains latency stage of viral life cycle in a variety of cell types including cells of epithelial, mesenchymal and endothelial origin. The establishment of latent infection by KSHV requires the expression of an unique repertoire of genes among which latency associated nuclear antigen (LANA) plays a critical role in the replication of the viral genome. LANA regulates the transcription of a number of viral and cellular genes essential for the survival of the virus in the host cell. The present study demonstrates the disruption of the host G2/M cell cycle checkpoint regulation as an associated function of LANA. DNA profile of LANA expressing human B-cells demonstrated the ability of this nuclear antigen in relieving the drug (Nocodazole) induced G2/M checkpoint arrest. Caffeine suppressed nocodazole induced G2/M arrest indicating involvement of the ATM/ATR. Notably, we have also shown the direct interaction of LANA with Chk2, the ATM/ATR signalling effector and is responsible for the release of the G2/M cell cycle block.
ABSTRACTEpstein-Barr virus (EBV) was the first human DNA virus to be associated with cancer. Its ... more ABSTRACTEpstein-Barr virus (EBV) was the first human DNA virus to be associated with cancer. Its oncogenic potential was further demonstrated by its ability to transform primary B lymphocytes in vitro. EBV nuclear antigen 3C (EBNA3C) is one of a small subset of latent antigens critical for the transformation of human primary B lymphocytes. Although EBNA3C has been shown to modulate several cellular functions, additional targets involved in cellular transformation remain to be explored. EBNA3C can recruit key components of the SCFSkp2ubiquitin ligase complex. In this report, we show that EBNA3C residues 130 to 190, previously shown to bind to the SCFSkp2complex, also can strongly associate with the c-Myc oncoprotein. Additionally, the interaction of EBNA3C with c-Myc was mapped to the region of c-Myc that includes the highly conserved Skp2 binding domain. Skp2 has been shown to regulate c-Myc stability and also has been shown to function as a coactivator of transcription for c-Myc ta...
The small molecule Quinacrine (QC, a derivative of 9‐aminoacridine), an anti‐malaria drug, displa... more The small molecule Quinacrine (QC, a derivative of 9‐aminoacridine), an anti‐malaria drug, displays activity against cancer cell lines and can simultaneously suppress nuclear factor‐κB (NF‐κB) and activate p53 signaling. In this study, we investigated the anticancer mechanism underlying these drug activities in breast cancer cell lines. QC caused a dose‐dependent decrease of both anchorage dependent and independent growth of breast cancer cells (MCF‐7 and MDA‐MB‐231) without affecting normal breast epithelial cells (MCF‐10A), as evident from clonogenic cell survival, [3‐(4,5‐dimethylthiazol‐2yl‐)‐2,5‐diphenyl tetrazolium bromide] viability, wound healing and soft agar growth. QC activated the proapoptotic marker Bax, PARP cleavage, p53 and its downstream target, p21 (Cip1/Waf1) and downregulated the antiapoptotic marker Bcl‐xL and relative luciferase activity of NF‐κB in MCF‐7 cells. Results of DAPI nuclear staining and FACS analysis show that QC increased apoptosis in a dose‐depend...
Nm23-H1 is a well-known tumor metastasis suppressor, which functions as a nucleosidediphosphate k... more Nm23-H1 is a well-known tumor metastasis suppressor, which functions as a nucleosidediphosphate kinase converting nucleoside diphosphates to nucleoside triphosphates with an expense of ATP. It regulates a variety of cellular activities, including proliferation, development, migration and differentiation known to be modulated by a series of complex signaling pathway. Few studies have addressed the mechanistic action of Nm23-H1 in the context of these cellular processes. To determine the downstream pathways modulated by Nm23-H1, we expressed Nm23-H1 in a Burkitt lymphoma derived B-cell line BJAB and performed pathway specific microarray analysis. The genes with significant changes in expression patterns were clustered in groups which are responsible for regulating cell cycle, p53 activities and apoptosis. We found a general reduction of cell cycle regulatory proteins including cyclins and cyclin dependent kinase inhibitors (anti proliferation), and upregulation of apoptotic genes which included caspase 3, 9 and Bcl-x. Nm23-H1 was also found to upregulate p53 and downregulate p21 expression. A number of these genes were validated by real time PCR and results from promoter assays indicated that Nm23-H1 expression downregulated cyclin D1 in a dose responsive manner. Further, we show that Nm23-H1 forms a complex with the cellular transcription factor AP1 to modulate cyclin D1 expression levels. BJAB cells expressing Nm23-H1 showed reduced proliferation rate and were susceptible to increased apoptosis which may in part be due to a direct interaction between Nm23-H1 and p53. These results suggest that Nm23-H1 may have a role in the regulation of cell cycle and apoptosis in human B-cells.
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Papers by Sushil Sahu