Lysophosphatidic Acid Promotes Epithelial to Mesenchymal Transition in Ovarian Cancer Cells by Repressing SIRT1

Epithelial-to-mesenchymal transition (EMT) plays an essential role in the transition from early to invasive phenotype, however the underlying mechanisms still remain elusive. Herein, we propose a mechanism through which the class-III deacetylase SIRT1 regulates EMT in ovarian cancer (OC) cells. Methods: Expression analysis was performed using Q-PCR, western blot, immunofluorescence and fluorescence-IHC study. Matrigel invasion assay was used for the invasion study. Morphological alterations were observed by phalloidin-staining. Co-immunoprecipitation study was performed to analyze protein-protein interaction. Results: Overexpression of SIRT1-WT as well as Resveratrol-mediated SIRT1 activation antagonized the invasion of OC cells by suppressing EMT. SIRT1 deacetylates HIF1α, to inactivate its transcriptional activity. To further validate HIF1α inactivation, its target gene, i.e. ZEB1, an EMTinducing factor was found to attenuate upon SIRT1 activation. To uncover the regulatory factor governing SIRT1 expression, lysophosphatidic acid (LPA), a highly enriched oncolipid in ascites/ serum of OC patients, was found to down-regulate SIRT1 expression. Importantly, LPA was found to induce the mesenchymal switch in OC cells through suppression of SIRT1. Decreased level of SIRT1 was further validated in ovarian tissue samples of OC patients. Conclusion: We have identified a mechanism that relates SIRT1 down-regulation to LPA-induced EMT in OC cells and may open new arenas on developing novel anti-cancer therapeutics

FORMULATION OF NANOPARTICLES OF TELMISARTAN INCORPORATED IN CARBOXYMETHYLCHITOSAN FOR THE BETTER DRUG DELIVERY AND ENHANCED BIOAVAILABILITY

  Objective: In this study, we have made an attempt to the developed formulation of nanoparticles (NPs) of telmisartan (TLM) incorporated in carboxymethyl chitosan (CMCS) for the better drug delivery and enhanced bioavailability.Materials and Methods: The NPs size and morphology were investigated by high-resolution transmission electron microscopy and field emission scanning electron microscopy, respectively. The crystal structures and surface functional groups were analyzed using X-ray diffraction pattern, and Fourier transform infrared spectroscopy, respectively.Results: To increase the solubility of TLM by targeted delivery of the drug through polymeric NPs is an alternative efficient, option for increasing the solubility. TLM nanosuspension powders were successfully formulated for dissolution and bioavailability enhancement of the drug. We focused on evaluating the influence of particle size and crystalline state on the in vitro and in vivo performance of TLM.Conclusion: In summary, we have developed a new approach toward the delivery of poorly water-soluble drug TLM by CMCS NPs. The particles having a good drug loading content and drug encapsulation efficiency. The cytotoxicity of the synthesized NPs is also very less

Invasion of ovarian cancer cells is induced by PITX2-mediated activation of TGF-β and Activin-A

Background:Most ovarian cancers are highly invasive in nature and the high burden of metastatic disease make them a leading cause of mortality among all gynaecological malignancies. The homeodomain transcription factor, PITX2 is associated with cancer in different tissues. Our previous studies demonstrated increased PITX2 expression in human ovarian tumours. Growing evidence linking activation of TGF-β pathway by homeodomain proteins prompted us to look for the possible involvement of this signalling pathway in PITX2-mediated progression of ovarian cancer. Methods: The status of TGF-β signalling in human ovarian tissues was assessed by immunohistochemistry. The expression level of TGFB/INHBA and other invasion-associated genes was measured by quantitative-PCR (Q-PCR) and Western Blot after transfection/treatments with clones/reagents in normal/cancer cells. The physiological effect of PITX2 on invasion/motility was checked by matrigel invasion and wound healing assay. The PITX2- and activin-induced epithelial-mesenchymal transition (EMT) was evaluated by Q-PCR of respective markers and confocal/phase-contrast imaging of cells. Results: Human ovarian tumours showed enhanced TGF-β signalling. Our study uncovers the PITX2-induced expression of TGFB1/2/3 as well as INHBA genes (p < 0.01) followed by SMAD2/3-dependent TGF-β signalling pathway. PITX2-induced TGF-β pathway regulated the expression of invasion-associated genes, SNAI1, CDH1 and MMP9 (p < 0.01) that accounted for enhanced motility/invasion of ovarian cancers. Snail and MMP9 acted as important mediators of PITX2-induced invasiveness of ovarian cancer cells. PITX2 over-expression resulted in loss of epithelial markers (p < 0.01) and gain of mesenchymal markers (p < 0.01) that contributed significantly to ovarian oncogenesis. PITX2-induced INHBA expression (p < 0.01) contributed to EMT in both normal and ovarian cancer cells. Conclusions: Overall, our findings suggest a significant contributory role of PITX2 in promoting invasive behaviour of ovarian cancer cells through up-regulation of TGFB/INHBA. We have also identified the previously unknown involvement of activin-A in promoting EMT. Our work provides novel mechanistic insights into the invasive behavior of ovarian cancer cells. The extension of this study have the potential for therapeutic applications in future

SARS-CoV-2 Nucleocapsid Assembly Inhibitors: Repurposing Antiviral and Antimicrobial Drugs Targeting Nucleocapsid-RNA Interaction

SARS-CoV-2 pandemic has become a serious concern due to high transmission of this virus and unavailability of any definitive drugs yet in clinics. While novel antivirals are under investigation stage, scientists are also rigorously trying to use drug repurposing as an option to fight against this highly infectious novel coronavirus. Several drugs are under regular use for other diseases that are getting screened for their usability against SARS-CoV2. In this study we have targeted SARS-CoV-2 nucleocapsid assembly to shortlist FDA approved drugs that could be tested for inhibition of SARS-CoV-2 virus particles inside the host cell. We could shortlist five antiviral and anti-microbial drugs. These showed good fit in docking studies inside the RNA binding cleft of the nucleocapsid protein. Also, these drugs have lipophilic properties suggesting that they have the potential to enter the host cells. We propose that these shortlisted drugs could potentially compete out binding of viral RNA to nucleocapsid and thus inhibit successful virus assembly leading to poor virus progeny levels. </p

Repurposing Nonnucleoside Antivirals Against SARS-CoV2 NSP12 (RNA Dependent RNA Polymerase) and Identification of Domain Specific Interactions

The pandemic of SARS-CoV-2 has necessitated expedited research efforts towards finding potential antiviral targets and drug development measures. While new drug discovery is time consuming, drug repurposing has been a promising area for elaborate virtual screening and identification of existing FDA approved drugs that could possibly be used for targeting against functions of various proteins of SARS-CoV-2 virus. RNA dependent RNA polymerase (RdRp) is an important enzyme for the virus that mediates replication of the viral RNA. Inhibition of RdRp could inhibit viral RNA replication and thus new virus particle production. Here, we screened non-nucleoside antivirals and found three out of them to be strongest in binding to RdRp. We propose these three drugs as potential RdRp inhibitors based on the site of binding. </p

Antibody–Drug Conjugates for Multiple Myeloma: Just the Beginning, or the Beginning of the End?

Multiple myeloma is a malignancy of immunoglobulin-secreting plasma cells that is now often treated in the newly diagnosed and relapsed and/or refractory settings with monoclonal antibodies targeting lineage-specific markers used either alone or in rationally designed combination regimens. Among these are the anti-CD38 antibodies daratumumab and isatuximab, and the anti-Signaling lymphocytic activation molecule family member 7 antibody elotuzumab, all of which are used in their unconjugated formats. Single-chain variable fragments from antibodies also form a key element of the chimeric antigen receptors (CARs) in the B-cell maturation antigen (BCMA)-targeted CAR T-cell products idecabtagene vicleucel and ciltacabtagene autoleucel, which are approved in the advanced setting. Most recently, the bispecific anti-BCMA and T-cell-engaging antibody teclistamab has become available, again for patients with relapsed/refractory disease. Another format into which antibodies can be converted to exert anti-tumor efficacy is as antibody–drug conjugates (ADCs), and belantamab mafodotin, which also targets BCMA, represented the first such agent that gained a foothold in myeloma. Negative results from a recent Phase III study have prompted the initiation of a process for withdrawal of its marketing authorization. However, belantamab remains a drug with some promise, and many other ADCs targeting either BCMA or other plasma cell surface markers are in development and showing potential. This contribution will provide an overview of some of the current data supporting the possibility that ADCs will remain a part of our chemotherapeutic armamentarium against myeloma moving forward, and also highlight areas for future development

Ribosome-RNA interaction: a potential target for developing antiviral against hepatitis C virus

Hepatitis C virus (HCV), a member of Flaviviridae, encoding a positive-sense single-stranded RNA translates by cap-independent mechanism using the internal ribosome entry site (IRES) present in the 5' UTR of the virus. The IRES has complex stem loop structures and is capable of recruiting the 40S ribosomal subunit in a factor-independent fashion. As the IRES sequence is highly conserved throughout the HCV genotypes and the translation is the first obligatory step of the HCV life cycle, the IRE'S-mediated translation, or more specifically, the ribosome HCV RNA interaction is an attractive target to design effective antivirals. This article will focus on the mechanism of the HCV IRES translation and the various ways in which the interaction of ribosome and IRES has been targeted

Drug Repurposing Commonly Against Dengue Virus Capsid and SARS-CoV-2 Nucleocapsid: An in Silico Approach

In the middle of SARS-CoV-2 pandemic, dengue virus (DENV) is giving a silent warning as the season approaches nearer. There is no specific antiviral against DENV for use in the clinics. Thus, considering these facts we can potentially face both these viruses together increasing the clinical burden. The search for anti-viral drugs against SARS-CoV-2 is in full swing and repurposing of already ‘in-use’ drugs against other diseases or COVID-19 has drawn significant attention. Earlier we had reported few FDA approved anti-viral and anti-microbial drugs that could be tested for binding with SARS-CoV-2 nucleocapsid N terminal domain. We explored the possibility of interactions of the drugs screened for SARS-CoV2 with Dengue virus capsid protein. We report five FDA approved drugs that were seen to be docking onto the SARS-CoV-2 nucleocapsid RNA binding domain, also docking well with DENV capsid protein on the RNA binding site and/or the capsid’s membrane fusion domain. Thus, the present study proposes these five drugs as common antiviral candidates against both SARS-CoV-2 and DENV although the in silico study is subject to further validations.</p

Human la protein interaction with GCAC near the initiator AUG enhances hepatitis C virus RNA replication by promoting linkage between 5 ` and 3 ` untranslated regions

Human La protein has been implicated in facilitating the internal initiation of translation as well as replication of hepatitis C virus (HCV) RNA. Previously, we demonstrated that La interacts with the HCV internal ribosome entry site (IRES) around the GCAC motif near the initiator AUG within stem-loop IV by its RNA recognition motif (RRM) (residues 112 to 184) and influences HCV translation. In this study, we have deciphered the role of this interaction in HCV replication in a hepatocellular carcinoma cell culture system. We incorporated mutation of the GCAC motif in an HCV monocistronic subgenomic replicon and a pJFH1 construct which altered the binding of La and checked HCV RNA replication by reverse transcriptase PCR (RT-PCR). The mutation drastically affected HCV replication. Furthermore, to address whether the decrease in replication is a consequence of translation inhibition or not, we incorporated the same mutation into a bicistronic replicon and observed a substantial decrease in HCV RNA levels. Interestingly, La overexpression rescued this inhibition of replication. More importantly, we observed that the mutation reduced the association between La and NS5B. The effect of the GCAC mutation on the translation-to-replication switch, which is regulated by the interplay between NS3 and La, was further investigated. Additionally, our analyses of point mutations in the GCAC motif revealed distinct roles of each nucleotide in HCV replication and translation. Finally, we showed that a specific interaction of the GCAC motif with human La protein is crucial for linking 5' and 3' ends of the HCV genome. Taken together, our results demonstrate the mechanism of regulation of HCV replication by interaction of the cis-acting element GCAC within the HCV IRES with human La protein