Browsing by Author "Tikoo, Kulbhushan"

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Design and synthesis of non-covalent imidazo[1,2-a]quinoxaline-based inhibitors of EGFR and their anti-cancer assessment
(MDPI AG, 2021-03-09T00:00:00) Kumar, Manvendra; Joshi, Gaurav; Arora, Sahil; Singh, Tashvinder; Biswas, Sajal; Sharma, Nisha; Bhat, Zahid Rafiq; Tikoo, Kulbhushan; Singh, Sandeep; Kumar, Raj
A series of 30 non-covalent imidazo[1,2-a]quinoxaline-based inhibitors of epidermal growth factor receptor (EGFR) were designed and synthesized. EGFR inhibitory assessment (against wild type) data of compounds revealed 6b, 7h, 7j, 9a and 9c as potent EGFRWT inhibitors with IC50 values of 211.22, 222.21, 193.18, 223.32 and 221.53 nM, respectively, which were comparable to erlotinib (221.03 nM), a positive control. Furthermore, compounds exhibited excellent antiproliferative activity when tested against cancer cell lines harboring EGFRWT; A549, a non-small cell lung cancer (NSCLC), HCT-116 (colon), MDA-MB-231 (breast) and gefitinib-resistant NSCLC cell line H1975 harboring EGFRL858R/T790M. In particular, compound 6b demonstrated significant inhibitory potential against gefitinib-resistant H1975 cells (IC50 = 3.65 �M) as compared to gefitinib (IC50 > 20 �M). Moreover, molecular docking disclosed the binding mode of the 6b to the domain of EGFR (wild type and mutant type), indicating the basis of inhibition. Furthermore, its effects on redox modulation, mitochondrial membrane potential, cell cycle analysis and cell death mode in A549 lung cancer cells were also reported. Copyright: � 2021 by the authors. Licensee MDPI, Basel, Switzerland.
In Vivo Anticancer Evaluation of 6b, a Non-Covalent Imidazo[1,2-a]quinoxaline-Based Epidermal Growth Factor Receptor Inhibitor against Human Xenograft Tumor in Nude Mice
(MDPI, 2022-08-30T00:00:00) Bhat, Zahid Rafiq; Kumar, Manvendra; Sharma, Nisha; Yadav, Umesh Prasad; Singh, Tashvinder; Joshi, Gaurav; Pujala, Brahmam; Raja, Mohd; Chatterjee, Joydeep; Tikoo, Kulbhushan; Singh, Sandeep; Kumar, Raj
Tyrosine kinase inhibitors are validated therapeutic agents against EGFR-mutated non-small cell lung cancer (NSCLC). However, the associated critical side effects of these agents are inevitable, demanding more specific and efficient targeting agents. Recently, we have developed and reported a non-covalent imidazo[1,2-a]quinoxaline-based EGFR inhibitor (6b), which showed promising inhibitory activity against the gefitinib-resistant H1975(L858R/T790M) lung cancer cell line. In the present study, we further explored the 6b compound in vivo by employing the A549-induced xenograft model in nude mice. The results indicate that the administration of the 6b compound significantly abolished the growth of the tumor in the A549 xenograft nude mice. Whereas the control mice bearing tumors displayed a declining trend in the survival curve, treatment with the 6b compound improved the survival profile of mice. Moreover, the histological examination showed the cancer cell cytotoxicity of the 6b compound was characterized by cytoplasmic destruction observed in the stained section of the tumor tissues of treated mice. The immunoblotting and qPCR results further signified that 6b inhibited EGFR in tissue samples and consequently altered the downstream pathways mediated by EGFR, leading to a reduction in cancer growth. Therefore, the in vivo findings were in corroboration with the in vitro results, suggesting that 6b possessed potential anticancer activity against EGFR-dependent lung cancer. 6b also exhibited good stability in human and mouse liver microsomes. � 2022 by the authors.
L-Methionine prevents ?-cell damage by modulating the expression of Arx, MafA and regulation of FOXO1 in type 1 diabetic rats
(Elsevier GmbH, 2021-12-03T00:00:00) Navik, Umashanker; Rawat, Kajal; Tikoo, Kulbhushan
L-Methionine (L-Met) is an essential sulphur-containing amino acid having a vital role in various key cellular processes. Here we investigated the effect of L-Met on streptozotocin-induced ?-cell damage model of diabetes mellitus in Sprague Dawley rats. At the end of study biochemical parameters, immunoblotting, qRT-PCR and ChIP-qPCR are performed. L-Met was administered orally (250 and 500 mg/kg/day) to diabetic animals for 8 weeks improved plasma glucose and insulin levels. Pancreas immunohistochemistry showed significant increase in insulin expression, decrease in glucagon and Bax expression. Interestingly, L-Met inhibited the expression of Arx; upregulated MafA and FOXO1 which play a critical role in the maintenance of ?-cell identity. Our data also showed a decrease in H3K27me3 and an increase in H3K4me3 (�bivalent domain� alteration) in diabetic rats and these recovered by L-Met. Furthermore, the chromatin-immunoprecipitation assay showed a decreased enrichment of H3K27me3 on the promoter of the FOXO1 gene in diabetic rats and L-Met prevents this decrease. Our results showed the first evidence of the involvement of H3K27me3 in regulating the expression of the FOXO1 gene and the prevention of ?-cell injury by L-Met treatment. In conclusion, we report the involvement of L-Met in the modulation of ?-cell identity marker (Arx), ?-cell identity marker (MafA) and regulation of FOXO1 by histone methylation marks for the first time. We are of the opinion that this employed as a novel therapeutic approach for mitigating diabetes-induced ?-cell death. � 2021 Elsevier GmbH
L-Methionine supplementation attenuates high-fat fructose diet-induced non-alcoholic steatohepatitis by modulating lipid metabolism, fibrosis, and inflammation in rats
(Royal Society of Chemistry, 2022-03-31T00:00:00) Navik, Umashanker; Sheth, Vaibhav G.; Sharma, Nisha; Tikoo, Kulbhushan
Recently, the protective effects of a methionine-rich diet on hepatic oxidative stress and fibrosis have been suggested but not adequately studied. We, therefore, hypothesized that l-methionine supplementation would ameliorate the progression of hepatic injury in a diet-induced non-alcoholic steatohepatitis (NASH) model and aimed to investigate the underlying mechanism. NASH was developed in male Sprague Dawley rats by feeding them with a high-fat-fructose diet (HFFrD) for 10 weeks. The results demonstrated that l-methionine supplementation to NASH rats for 16 weeks improved the glycemic, lipid, and liver function profiles in NASH rats. Histological analysis of liver tissue revealed a remarkable improvement in the three classical lesions of NASH: steatosis, inflammation, and ballooning. Besides, l-methionine supplementation ameliorated the HFFrD-induced enhanced lipogenesis and lipid peroxidation. An anti-inflammatory effect of l-methionine was also observed through the inhibition of the release of proinflammatory cytokines. Furthermore, the hepatic SIRT1/AMPK signaling pathway was associated with the beneficial effects of l-methionine. This study demonstrates that l-methionine supplementation in HFFrD-fed rats improves their liver pathology via regulation of lipogenesis, inflammation, and the SIRT1/AMPK pathway, thus encouraging its clinical evaluation for the treatment of NASH. � 2022 The Royal Society of Chemistry.
Methionine as a double-edged sword in health and disease: Current perspective and future challenges
(Elsevier Ireland Ltd, 2021-10-25T00:00:00) Navik, Umashanker; Sheth, Vaibhav G.; Khurana, Amit; Jawalekar, Snehal Sainath; Allawadhi, Prince; Gaddam, Ravinder Reddy; Bhatti, Jasvinder Singh; Tikoo, Kulbhushan
Methionine is one of the essential amino acids and plays a vital role in various cellular processes. Reports advocate that methionine restriction and supplementation provide promising outcomes, and its regulation is critical for maintaining a healthy life. Dietary methionine restriction in houseflies and rodents has been proven to extend lifespan. Contrary to these findings, long-term dietary restriction of methionine leads to adverse events such as bone-related disorders, stunted growth, and hyperhomocysteinemia. Conversely, dietary supplementation of methionine improves hepatic steatosis, insulin resistance, inflammation, fibrosis, and bone health. However, a high level of methionine intake shows adverse effects such as hyperhomocysteinemia, reduced body weight, and increased cholesterol levels. Therefore, dietary methionine in a safe dose could have medicinal values. Hence, this review is aimed to provide a snapshot of the dietary role and regulation of methionine in the modulation of health and age-related diseases. � 2021 Elsevier B.V.