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result(s) for
"Kanumuri, Rahul"
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Fabrication of bioactive corrosion-resistant polyaniline/TiO2 nanotubes nanocomposite and their application in orthopedics
by
Rajendran, Nallaiyan
,
Rayala, Suresh Kumar
,
Kanumuri Rahul
in
Anatase
,
Antiinfectives and antibacterials
,
Biocompatibility
2020
The long-term permanence of titanium implant was improved by incorporation of polyaniline on TiO2 nanotubes. The polyaniline incorporated TiO2 nanotubes (PANI-2/TNTA) has enhanced the bioactivity and corrosion resistance. Highly ordered nanotubes were formed on the titanium metal with an average tube diameter of ~ 85 nm which was confirmed by HR-SEM. The presence of anatase and rutile mixed phases was identified by XRD analysis. The formation of interfacial bonding between PANI and TNTA was confirmed by Raman and XPS analysis. The lower corrosion current density and higher polarization resistance (Rp) obtained for PANI-2/TNTA nanocomposite revealed the enhanced corrosion resistance behavior in physiological conditions. To ensure the durability of PANI-2/TNTA, the corrosion behavior was analyzed at different applied potentials using dynamic electrochemical impedance spectroscopy (DEIS). Up to 1 V, the higher impedance value was observed in Hanks’ solution. The bioactivity of the PANI-2/TNTA nanocomposite was confirmed by the more-notable cell adhesion and proliferation of MG-63 osteoblast-like cells. PANI-2/TNTA has the ability to reduce implant-associated infections. The existence of the amine group is responsible for better biostability and antimicrobial activity.Graphic abstract
Journal Article
Sustainable production of camptothecin from an Alternaria sp. isolated from Nothapodytes nimmoniana
2021
Camptothecin the third most in demand alkaloid, is commercially extracted in India from the endangered plant,
Nothapodytes nimmoniana
. Endophytes, the microorganisms that reside within plants, are reported to have the ability to produce host–plant associated metabolites. Hence, our research aims to establish a sustainable and high camptothecin yielding endophyte, as an alternative source for commercial production of camptothecin. A total of 132 endophytic fungal strains were isolated from different plant parts (leaf, petiole, stem and bark) of
N. nimmoniana
, out of which 94 were found to produce camptothecin in suspension culture.
Alternaria alstroemeriae
(NCIM1408) and
Alternaria burnsii
(NCIM1409) demonstrated camptothecin yields up to 426.7 ± 33.6 µg/g DW and 403.3 ± 41.6 µg/g DW, respectively, the highest reported production to date. Unlike the reported product yield attenuation in endophytes with subculture in axenic state,
Alternaria burnsii
NCIM1409 could retain and sustain the production of camptothecin up to ~ 200 μg/g even after 12 continuous subculture cycles. The camptothecin biosynthesis in
Alternaria burnsii
NCIM1409 was confirmed using
13
C carbon labelling (and cytotoxicity analysis on different cancer cell lines) and this strain can now be used to develop a sustainable bioprocess for in vitro production of camptothecin as an alternative to plant extraction.
Journal Article
Obesity-induced inflammation exacerbates clonal hematopoiesis
2023
Characterized by the accumulation of somatic mutations in blood cell lineages, clonal hematopoiesis of indeterminate potential (CHIP) is frequent in aging and involves the expansion of mutated hematopoietic stem and progenitor cells (HSC/Ps) that leads to an increased risk of hematologic malignancy. However, the risk factors that contribute to CHIP-associated clonal hematopoiesis (CH) are poorly understood. Obesity induces a proinflammatory state and fatty bone marrow (FBM), which may influence CHIP-associated pathologies. We analyzed exome sequencing and clinical data for 47,466 individuals with validated CHIP in the UK Biobank. CHIP was present in 5.8% of the study population and was associated with a significant increase in the waist-to-hip ratio (WHR). Mouse models of obesity and CHIP driven by heterozygosity of Tet2, Dnmt3a, Asxl1, and Jak2 resulted in exacerbated expansion of mutant HSC/Ps due in part to excessive inflammation. Our results show that obesity is highly associated with CHIP and that a proinflammatory state could potentiate the progression of CHIP to more significant hematologic neoplasia. The calcium channel blockers nifedipine and SKF-96365, either alone or in combination with metformin, MCC950, or anakinra (IL-1 receptor antagonist), suppressed the growth of mutant CHIP cells and partially restored normal hematopoiesis. Targeting CHIP-mutant cells with these drugs could be a potential therapeutic approach to treat CH and its associated abnormalities in individuals with obesity.
Journal Article
Alkynyl nicotinamides show antileukemic activity in drug-resistant acute myeloid leukemia
by
Aman, M. Javad
,
Liu, Sheng
,
Chu, Elizabeth Fei Yin
in
Animals
,
Antimitotic agents
,
Antineoplastic agents
2024
Activating mutations of FLT3 contribute to deregulated hematopoietic stem and progenitor cell (HSC/Ps) growth and survival in patients with acute myeloid leukemia (AML), leading to poor overall survival. AML patients treated with investigational drugs targeting mutant FLT3, including Quizartinib and Crenolanib, develop resistance to these drugs. Development of resistance is largely due to acquisition of cooccurring mutations and activation of additional survival pathways, as well as emergence of additional FLT3 mutations. Despite the high prevalence of FLT3 mutations and their clinical significance in AML, there are few targeted therapeutic options available. We have identified 2 novel nicotinamide-based FLT3 inhibitors (HSN608 and HSN748) that target FLT3 mutations at subnanomolar concentrations and are potently effective against drug-resistant secondary mutations of FLT3. These compounds show antileukemic activity against FLT3ITD in drug-resistant AML, relapsed/refractory AML, and in AML bearing a combination of epigenetic mutations of TET2 along with FLT3ITD. We demonstrate that HSN748 outperformed the FDA-approved FLT3 inhibitor Gilteritinib in terms of inhibitory activity against FLT3ITD in vivo.
Journal Article
Small peptide inhibitor from the sequence of RUNX3 disrupts PAK1–RUNX3 interaction and abrogates its phosphorylation-dependent oncogenic function
2021
P21 Activated Kinase 1 (PAK1) is an oncogenic serine/threonine kinase known to play a significant role in the regulation of cytoskeleton and cell morphology. Runt-related transcription factor 3 (RUNX3) was initially known for its tumor suppressor function, but recent studies have reported the oncogenic role of RUNX3 in various cancers. Previous findings from our laboratory provided evidence that Threonine 209 phosphorylation of RUNX3 acts as a molecular switch in dictating the tissue-specific dualistic functions of RUNX3 for the first time. Based on these proofs and to explore the translational significance of these findings, we designed a small peptide (RMR) from the protein sequence of RUNX3 flanking the Threonine 209 phosphorylation site. The selection of this specific peptide from multiple possible peptides was based on their binding energies, hydrogen bonding, docking efficiency with the active site of PAK1 and their ability to displace PAK1–RUNX3 interaction in our prediction models. We found that this peptide is stable both in in vitro and in vivo conditions, not toxic to normal cells and inhibits the Threonine 209 phosphorylation in RUNX3 by PAK1. We also tested the efficacy of this peptide to block the RUNX3 Threonine 209 phosphorylation mediated tumorigenic functions in in vitro cell culture models, patient-derived explant (PDE) models and in in vivo tumor xenograft models. These results proved that this peptide has the potential to be developed as an efficient therapeutic molecule for targeting RUNX3 Threonine 209 phosphorylation-dependent tumor phenotypes.
Journal Article
Loss of Dnmt3a impairs hematopoietic homeostasis and myeloid cell skewing via the PI3Kinase pathway
by
Perna, Fabiana
,
Szymanski, Megan
,
Sandusky, George
in
1-Phosphatidylinositol 3-kinase
,
Actin
,
Acute myeloid leukemia
2023
Loss-of-function mutations in the DNA methyltransferase 3A (DNMT3A) are seen in a large number of patients with acute myeloid leukemia (AML) with normal cytogenetics and are frequently associated with poor prognosis. DNMT3A mutations are an early preleukemic event, which - when combined with other genetic lesions - result in full-blown leukemia. Here, we show that loss of Dnmt3a in hematopoietic stem and progenitor cells (HSC/Ps) results in myeloproliferation, which is associated with hyperactivation of the phosphatidylinositol 3-kinase (PI3K) pathway. PI3Kα/β or the PI3Kα/δ inhibitor treatment partially corrects myeloproliferation, although the partial rescue is more efficient in response to the PI3Kα/β inhibitor treatment. In vivo RNA-Seq analysis on drug-treated Dnmt3a-/- HSC/Ps showed a reduction in the expression of genes associated with chemokines, inflammation, cell attachment, and extracellular matrix compared with controls. Remarkably, drug-treated leukemic mice showed a reversal in the enhanced fetal liver HSC-like gene signature observed in vehicle-treated Dnmt3a-/- LSK cells as well as a reduction in the expression of genes involved in regulating actin cytoskeleton-based functions, including the RHO/RAC GTPases. In a human PDX model bearing DNMT3A mutant AML, PI3Kα/β inhibitor treatment prolonged their survival and rescued the leukemic burden. Our results identify a potentially new target for treating DNMT3A mutation-driven myeloid malignancies.
Journal Article
Alkynyl nicotinamides show antileukemic activity in drug-resistant acute myeloid leukemia
by
Aman, M Javad
,
Liu, Sheng
,
Chu, Elizabeth Fei Yin
in
Acute myeloid leukemia
,
Clinical significance
,
DNA methylation
2024
Activating mutations of FLT3 contribute to deregulated hematopoietic stem and progenitor cell (HSC/Ps) growth and survival in patients with acute myeloid leukemia (AML), leading to poor overall survival. AML patients treated with investigational drugs targeting mutant FLT3, including Quizartinib and Crenolanib, develop resistance to these drugs. Development of resistance is largely due to acquisition of cooccurring mutations and activation of additional survival pathways, as well as emergence of additional FLT3 mutations. Despite the high prevalence of FĽT3 mutations and their clinical significance in AML, there are few targeted therapeutic options available. We have identified 2 novel nicotinamide-based FLT3 inhibitors (HSN608 and HSN748) that target FLT3 mutations at subnanomolar concentrations and are potently effective against drug-resistant secondary mutations of FLT3. These compounds show antileukemic activity against FLT3ITD in drug-resistant AML, relapsed/refractory AML, and in AML bearing a combination of epigenetic mutations of TET2 along with FLT3ITD. We demonstrate that HSN748 outperformed the FDA-approved FLT3 inhibitor Gilteritinib in terms of inhibitory activity against FLT3ITD in vivo.
Journal Article
Obesity-induced inflammation exacerbates clonal hematopoiesis
by
Pandhiri, Taruni Reddy
,
Niroula, Abhishek
,
Yellapu, Nanda Kumar
in
Adipocytes
,
Animal models
,
Biobanks
2023
Characterized by the accumulation of somatic mutations in blood cell lineages, clonal hematopoiesis of indeterminate potential (CHIP) is frequent in aging and involves the expansion of mutated hematopoietic stem and progenitor cells (HSC/Ps) that leads to an increased risk of hematologic malignancy. However, the risk factors that contribute to CHIP-associated clonal hematopoiesis (CH) are poorly understood. Obesity induces a proinflammatory state and fatty bone marrow (FBM), which may influence CHIP-associated pathologies. We analyzed exome sequencing and clinical data for 47,466 individuals with validated CHIP in the UK Biobank. CHIP was present in 5.8% of the study population and was associated with a significant increase in the waist-to-hip ratio (WHR). Mouse models of obesity and CHIP driven by heterozygosity of Tet2, Dnmt3a, Asxll, and Jak2 resulted in exacerbated expansion of mutant HSC/Ps due in part to excessive inflammation. Our results show that obesity is highly associated with CHIP and that a proinflammatory state could potentiate the progression of CHIP to more significant hematologic neoplasia. The calcium channel blockers nifedipine and SKF-96365, either alone or in combination with metformin, MCC950, or anakinra (IL-1 receptor antagonist), suppressed the growth of mutant CHIP cells and partially restored normal hematopoiesis. Targeting CHIP-mutant cells with these drugs could be a potential therapeutic approach to treat CH and its associated abnormalities in individuals with obesity.
Journal Article
Novel BH4-BCL-2 Domain Antagonists Induce BCL-2-Mediated Apoptosis in Triple-Negative Breast Cancer
by
Ramasamy, Sakthivel
,
Saravanan, Roshni
,
Venkatraman, Ganesh
in
Antagonists (Biochemistry)
,
Antibiotics
,
Apoptosis
2022
Targeting the challenging tumors lacking explicit markers and predictors for chemosensitivity is one of the major impediments of the current cancer armamentarium. Triple-negative breast cancer (TNBC) is an aggressive and challenging molecular subtype of breast cancer, which needs astute strategies to achieve clinical success. The pro-survival B-cell lymphoma 2 (BCL-2) overexpression reported in TNBC plays a central role in deterring apoptosis and is a promising target. Here, we propose three novel BH4 mimetic small molecules, SM396, a covalent binder, and two non-covalent binders, i.e., SM216 and SM949, which show high binding affinity (nM) and selectivity, designed by remodeling the existing BCL-2 chemical space. Our mechanistic studies validate the selectivity of the compounds towards cancerous cells and not on normal cells. A series of functional assays illustrated BCL-2-mediated apoptosis in the tumor cells as a potent anti-cancerous mechanism. Moreover, the compounds exhibited efficacious in vivo activity as single agents in the MDA-MB-231 xenograft model (at nanomolar dosage). Overall, these findings depict SM216, SM396, and SM949 as promising leads, pointing to the clinical translation of these compounds in targeting triple-negative breast cancer.
Journal Article
Sustainable Production of Camptothecin from an Alternaria sp. isolated from Nothapodytes nimmoniana
by
Uma Shaanker Ramanan
,
Rayala, Suresh Kumar
,
Srivastava, Smita
in
Alternaria
,
Bark
,
Camptothecin
2020
A total of 132 endophytic fungal strains were isolated from different plant parts (leaf, petiole, stem and bark) of Nothapodytes nimmoniana, out of which 94 were found to produce camptothecin in suspension culture. Alternaria alstroemeriae (NCIM1408) and Alternaria burnsii (NCIM1409) demonstrated camptothecin yields up to 426.7+/-33.6 microgram/g DW and 403.3+/-41.6 microgram/g DW, respectively, the highest reported production to date. Unlike the reported product yield attenuation in endophytes with subculture in axenic state, Alternaria burnsii NCIM1409 could retain and sustain the production of camptothecin up to ~200 microgram/g even after 12 continuous subculture cycles. The camptothecin biosynthesis in Alternaria burnsii NCIM1409 was confirmed using 13C carbon labelling (and cytotoxicity analysis on different cancer cell lines) and this strain can now be used to develop a sustainable bioprocess for in vitro production of camptothecin as an alternative to plant extraction. Competing Interest Statement The authors have declared no competing interest.