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CURATOR
A pinboard by
Dr Pratap Acharya

Assistant Professor, Tripura University (A Central University), India

PINBOARD SUMMARY

SYNTHESIS OF α-TOCOPHEROL AND MEDIUM CHAIN FATTY ACID CONJUGATES WITH ENHANCED BIOLOGICAL PROFILE

LIPIDS: A CULPRIT OR SAVIOR?

Why lipids are culprit?

We often fear when we hear the word “lipid” in relation to our health. This fear is quite normal because of the terrifying risks associated with the elevated level of lipids in blood circulation. If we simply Google the key words “Lipids + Disease”, then almost all cardiovascular, renal, cerebral and hormonal diseases are going to pop-up on our computer screen. So, it is obvious that we must avoid lipids in our diets for a good health. But, then the question is why lipid even exists in our body when it is bad for health? The pursuit for the answer of this question gave new insights for my research area. If excessive lipid can create disease in human body, then it can also alter diseases if handled rightfully.

How lipids can be savior?

Our body cells are made up of a specialized lipid or derived lipid known as phospholipid. The drug molecules has to penetrate the lipid membrane in order to modify the diseases. There are several research which emphasize that individual cells produces bioactive lipid signaling that allows the cells to 'see' the surrounding environment and respond in ways that will benefit the whole body. Therefore, drugs that can reach these bioactive lipid targets will also produce successful drug candidates for various diseases.

What we do to defend lipids?

My current drug discovery research work is focused on development of new drug candidates for the treatment of inoperable cancers like leukemia, colon and lung cancer. To achieve this objective, we have synthesized several lipidised bioactive molecules and tested them against several human cancer cell lines. One such example is the lipidisation of antioxidant molecule such as α-Tocopherol with medium chain fatty acids. These molecules have exhibited strong antineoplastic properties as well as potent biofilm formation inhibitors in microbial infection. We have also successfully synthesized several 16-arylidene steroid derivatives as highly selective antileukemic agents [Steroids 2012, 77, 552-557; Arch. Pharm. Chem. Life Sci. 2014, 347, 193-199]. Few bioconjugates of steroids and alkylating agents has also been developed as potent antineoplastic agents using similar approach and found to have tremendous biological activity with no or lesser toxicity.

8 ITEMS PINNED

Machine-Learned Data Structures of Lipid Marker Serum Concentrations in Multiple Sclerosis Patients Differ from Those in Healthy Subjects.

Abstract: Lipid metabolism has been suggested to be a major pathophysiological mechanism of multiple sclerosis (MS). With the increasing knowledge about lipid signaling, acquired data become increasingly complex making bioinformatics necessary in lipid research. We used unsupervised machine-learning to analyze lipid marker serum concentrations, pursuing the hypothesis that for the most relevant markers the emerging data structures will coincide with the diagnosis of MS. Machine learning was implemented as emergent self-organizing feature maps (ESOM) combined with the U*-matrix visualization technique. The data space consisted of serum concentrations of three main classes of lipid markers comprising eicosanoids (d = 11 markers), ceramides (d = 10), and lyosophosphatidic acids (d = 6). They were analyzed in cohorts of MS patients (n = 102) and healthy subjects (n = 301). Clear data structures in the high-dimensional data space were observed in eicosanoid and ceramides serum concentrations whereas no clear structure could be found in lysophosphatidic acid concentrations. With ceramide concentrations, the structures that had emerged from unsupervised machine-learning almost completely overlapped with the known grouping of MS patients versus healthy subjects. This was only partly provided by eicosanoid serum concentrations. Thus, unsupervised machine-learning identified distinct data structures of bioactive lipid serum concentrations. These structures could be superimposed with the known grouping of MS patients versus healthy subjects, which was almost completely possible with ceramides. Therefore, based on the present analysis, ceramides are first-line candidates for further exploration as drug-gable targets or biomarkers in MS.

Pub.: 08 Jun '17, Pinned: 17 Aug '17

Sphingosine 1-phosphate signaling in bone remodeling: multifaceted roles and therapeutic potential.

Abstract: Sphingolipids belong to a complex class of lipid molecules that are crucially involved in the regulation of important biological processes including proliferation, migration and apoptosis. Given the significant progress made in understanding the sphingolipid pathobiology of several diseases, sphingolipid-related checkpoints emerge as attractive targets. Recent data indicate the multifaceted contribution of the sphingolipid machinery to osteoclast - osteoblast crosstalk, representing one of the pivotal interactions underlying bone homeostasis. Imbalances in the interplay of osteoblasts and osteoclasts might lead to bone-related diseases such as osteoporosis, rheumatoid arthritis and bone metastases. Areas covered: We summarize and analyze the progress made in bone research in the context of the current knowledge of sphingolipid-related mechanisms regulating bone remodeling. Particular emphasis was given to bioactive sphingosine 1-phosphate (S1P) and S1P receptors (S1PRs). Moreover, the mechanisms of how dysregulations of this machinery cause bone diseases, are covered. Expert opinion: In the context of bone diseases, pharmacological interference with sphingolipid machinery may lead to novel directions in therapeutic strategies. Implementation of knowledge derived from in vivo animal models and in vitro studies using pharmacological agents to manipulate the S1P/S1PRs axes suggests S1PR2 and S1PR3 as potential drug targets, particularly in conjunction with technology for local drug delivery.

Pub.: 20 May '17, Pinned: 17 Aug '17

In vitro and in vivo evaluation of anticancer actions of natural and synthetic vitamin E forms.

Abstract: The goal of these studies was to investigate the potential anticancer properties of two naturally occurring plant sources and two manufactured synthetic forms of vitamin E, i. e., RRR-alpha-tocopherol (alphaT), RRR-gamma-tocopherol (gammaT), all-rac-alpha-tocopherol (all-rac-alphaT), and all-rac-alpha-tocopheryl acetate (all-rac-alphaTAc) in breast cancer models. Vitamin E compounds were evaluated in vitro for inhibition of colony formation and induction of apoptosis in human MDA-MB-435 and MCF-7 breast cancer cells and murine 66cl-4 mammary cancer cells and in vivo for ability to reduce tumor growth and lung and lymph node metastases using the transplantable syngeneic BALB/c mouse 66cl-4-GFP mammary cancer model. gammaT inhibited colony formation and induced apoptosis in all three cancer cell lines. alphaT and all-rac-alphaT were less effective and all-rac-alphaTAc was ineffective. gammaT-induced apoptosis was correlated with activation of caspases-8 and -9 and down-regulation of protein expression of c-FLIP and survivin. In vivo study 1 analyses showed that all-rac-alphaT and all-rac-alphaTAc significantly inhibited tumor growth and inhibited both visible and microscopic size lung metastases. In vivo study 2 analyses showed that alphaT and gammaT reduced tumor growth, but only gammaT reduced tumor growth significantly in comparison to control. In conclusion, synthetic, but not natural, vitamin E exhibits promising anti-cancer properties in vivo.

Pub.: 03 Apr '08, Pinned: 09 Aug '17

Anticancer actions of natural and synthetic vitamin E forms: RRR-alpha-tocopherol blocks the anticancer actions of gamma-tocopherol.

Abstract: Two naturally occurring dietary sources of vitamin E (i.e. RRR-alpha-tocopherol (alphaT) and RRR-gamma-tocopherol (gammaT)), the manufactured synthetic form of vitamin E, all-racemic-alpha-tocopherol (all-rac-alphaT), as well as a potent antitumor analog of vitamin E, RRR-alpha-tocopherol ether-linked acetic acid analog (alpha-TEA), were assessed for anticancer actions. Data showed that gammaT, all-rac-alphaT, and alpha-TEA but not alphaT or alphaT+gammaT significantly inhibited tumor burden of human MDA-MB-231 cells in nude mice. Immunohistochemical analyses of tumor tissue showed that all-rac-alphaT and alpha-TEA increased apoptosis and decreased proliferation in tumor cells while gammaT was associated with increased tumor cell apoptosis only. In vitro data showed alpha-TEA and gammaT but not all-rac-alphaT or alphaT to inhibit colony formation and induce apoptosis. Anticancer actions of alpha-TEA and gammaT involved death receptor 5 protein upregulation, Survivin protein downregulation and poly (ADP-ribose) polymerase cleavage, all of which were blocked by co-treatment with alphaT. In summary, both gammaT and alpha-TEA exhibited promising anticancer properties in vivo and in vitro, whereas all-rac-alphaT exhibited promising anticancer properties in vivo only. Importantly, alphaT not only failed to exhibit anticancer properties but it also reduced anticancer actions of gammaT in vivo and gammaT and alpha-TEA in vitro.

Pub.: 21 Oct '09, Pinned: 09 Aug '17

Bioactive lipid profiling reveals drug target engagement of a soluble epoxide hydrolase inhibitor in a murine model of tobacco smoke exposure.

Abstract: The inflammatory process underlying chronic obstructive pulmonary disease (COPD) may be caused by tobacco smoke (TS) exposure. Previous studies show that epoxyeicosatrienoic acids (EETs) possess promising anti-inflammatory properties, therefore stabilization of EETs and other fatty acid epoxides through inhibition of soluble epoxide hydrolase (sEH) was investigated in mouse models of acute and sub-chronic inflammation caused by TS exposure. During the entire TS exposure, the potent sEH inhibitor 1-(1-methylsulfonyl-piperidin-4-yl)-3-(4-trifluoromethoxy-phenyl)-urea (TUPS) was given via drinking water. To assess drug target engagement of TUPS, a tandem mass spectrometry method was used for bioactive lipid profiling of a broad range of fatty acid metabolites, including EETs, and their corresponding diols (DHETs) derived from arachidonic acid, as well as epoxides and diols derived from other fatty acids. Several, but not all, plasma epoxide/diol ratios increased in mice treated with sEH inhibitor, compared to non-treated mice suggesting a wider role for sEH involving more fatty acid precursors besides arachidonic acid. This study supports qualitative use of epoxide/diol ratios explored by bioactive lipid profiling to indicate drug target engagement in mouse models of TS exposure relevant to COPD, which may have ramifications for future therapeutic interventions of sEH.

Pub.: 15 Apr '16, Pinned: 09 Aug '17