Megha Chagtoo - Academia.edu (original) (raw)

Papers by Megha Chagtoo

(A) PCA and (D) PLS-DA score plot generated for healthy control vs. patient group, (B) P... more (A) PCA and (D) PLS-DA score plot generated for healthy control vs. patient group, (B) PCA and (E) PLS-DA score plot generated for healthy control and high IP3R group, (C) PCA and (F) PLS-DA score plot generated for healthy control and low IP3R group.</p

Score plot and corresponding loading plot generated from PLS-DA analysis between (A) hea... more Score plot and corresponding loading plot generated from PLS-DA analysis between (A) healthy control and patient group, (B) healthy control and high IP3R group, (C) healthy control and low IP3R group.</p

An overview of the workflow performed for the serum metabolic profiling of breast cancer... more An overview of the workflow performed for the serum metabolic profiling of breast cancer patients using 1H NMR spectroscopy.</p

Relative mRNA expression of (A) IP3R1, (B) IP3</sub... more Relative mRNA expression of (A) IP3R1, (B) IP3R2 (p<0.001) and (C) IP3R3 (p<0.001) from tumoral and extra-tumoral tissues of breast cancer patients was analyzed using Real -time PCR. Analysis of tumoral and extra-tumoral tissues was done by incubating the tissue sections with antibodies against (D) IP3R2 and (E) IP3R3, and detected using DAB staining.</p

Relative integral areas are calculated from CPMG spectra and plotted as a.u.</p

The panel shows a view of metabolism in cancers depicting glycolysis and Krebs cycle whi... more The panel shows a view of metabolism in cancers depicting glycolysis and Krebs cycle which are modified to different processes like lipid and amino acid synthesis to meet the requirement of proliferating cells. (Metabolites depicted with green/red are decreased/increased in the present study).</p

Metabolites contributing to the difference between healthy control and high IP<sub&gt... more Metabolites contributing to the difference between healthy control and high IP3R patient group.</p

Glucose uptake in MCF-7 cells was analyzed using NBDG a fluorescently labeled deoxy gluc... more Glucose uptake in MCF-7 cells was analyzed using NBDG a fluorescently labeled deoxy glucose analogue as a probe for detection of glucose taken up by cultured cells. Quantitative estimation of glucose uptake, using a cell based assay kit, was performed as per instructions provided by the manufacturer (Cayman, USA). Cells were plated in 96-well plates and treated with 25 μM XeC for 24 hours or with siC (non-targeted siRNA) or siIP3R2 or siIP3R3 (72 hours,Fig7A and 7D) Representative graph in MCF-7 cells. (Fig 7B and 7E) Representative graph showing percentage of glucose uptake as estimated using cell based assay in MDA MB-231 cells. (Fig7C and 7F) Representative graph showing percentage of glucose uptake as estimated using cell based assay in MCF 10A cells. RNA was extracted from treated and untreated cells and cDNA was prepared (Fig 7G) RT profiler PCR array for glucose as well as mitochondrial metabolism genes was performed using cDNA prepared from mRNA of MCF-7 cells. Data represent mean ±SEM. *p< 0.05, ***p< 0.001 compared to vehicle.</p

Calcium signaling is very complex and intimately linked with cell survival and physiological form... more Calcium signaling is very complex and intimately linked with cell survival and physiological form of cell death. Endoplasmic reticulum is the main intracellular storage of Ca and release of Ca is controlled by ER membrane localized IP3Rs and RYRs. These receptors regulate the transfer of Ca from ER to mitochondria via transport protein on mitochondrial membrane which regulates cellular bioenergetics. Altered IP3R activity and/or the remodeling of IP3R-expression profiles may be exploited by cancer cells to promote growth and drug resistance. It can also affect mitochondrial bio-energetics and susceptibility to apoptotic stimuli, thereby enabling the survival of cells with oncogenic features. Three subtypes of IP3R (IP3R1, IP3R2, and IP3R3) share basic properties but differ in terms of regulation. To what extent they contribute to complex Ca signaling in cancer cells remains largely unknown. Understanding the detailed molecular regulation of IP3Rs will be important to develop novel t...

In the present work curcumin, demethoxycurcumin and bisdemethoxycurcumin have been synthesized an... more In the present work curcumin, demethoxycurcumin and bisdemethoxycurcumin have been synthesized and their inhibitory effects were studied on three different human breast cancer cell lines ZR-75, MDA-MB-231, HepG2 (Hepatocellular Carcinoma) and one normal cell line MCF10A. Their effects were compared with the cumulative effect of natural curcumin (Curcuminoid Mixture) through in vitro and in silico study. For in vitro screening, cytotoxicity analysis of curcuminoids was done in breast cancer cell lines, while changes in cellular and nuclear morphology were examined using phase contrast microscopy and Hoechst staining. Results obtained were further validated through in silico study, via examining role of seven major key regulatory proteins of breast cancer as targets of curcumin and curcuminoids. The individual curcuminoids and natural curcumin appear to act via different pathways causing apoptosis and necrosis. Based on the present study, it has been observed that synthetic curcumin, curcuminoids and their naturally occurring mixture significantly affect the molecular pathways of apoptosis and necrosis.

The Journal of endocrinology, 2015

Thyroid hormone (TH) through its receptor (TRα/β) influences spatio-temporal regulation of its ta... more Thyroid hormone (TH) through its receptor (TRα/β) influences spatio-temporal regulation of its target gene repertoire during brain development. Though hypothyroidism in WT rodent models of perinatal hypothyroidism severely impairs neurodevelopment, its effect on TRα/β knockout mice is less severe. An explanation to this paradox is attributed to a possible repressive action of unliganded TRs during development. Since unliganded TRs suppress gene expression through the recruitment of histone deacetylase (HDACs) via co-repressor complexes, we tested whether pharmacological inhibition of HDACs may prevent the effects of hypothyroidism on brain development. Using valproate, an HDAC inhibitor, we show that HDAC inhibition significantly blocks the deleterious effects of hypothyroidism on rat cerebellum, evident by recovery of TH target genes like Bdnf, Pcp2 and Mbp as well as improved dendritic structure of cerebellar Purkinje neurons. Together with this, HDAC inhibition also rescues hypot...

Multi-Targeted Approach to Treatment of Cancer, 2014

The inositol 1,4,5-trisphosphate (IP3) receptors (IP3Rs) are a family of Ca2+ release channels lo... more The inositol 1,4,5-trisphosphate (IP3) receptors (IP3Rs) are a family of Ca2+ release channels localized predominately in the endoplasmic reticulum of all cell types. They function to release Ca2+ into the cytoplasm in response to IP3 produced by diverse stimuli, generating complex local and global Ca2+ signals that regulate numerous cell physiological processes ranging from gene transcription and secretion to learning and memory. These receptors regulate the transfer of Ca2+ from ER to mitochondria via transport protein on mitochondrial membrane which regulates cellular bioenergetics. IP3R/Ca2+ release channel is most ubiquitously expressed which can enhance or inhibits autophagic process to induce cell death of cancer cells. There are evidences linking calcium homeostasis to the regulation of apoptotic and autophagic cell deaths. The present chapter will focus on the inositol triphosphate receptor and how this can be used as a tool to target cancer through autophagy.

Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease, 2014

Emerging evidences suggest that chronic inflammation is one of the major causes of tumorigenesis.... more Emerging evidences suggest that chronic inflammation is one of the major causes of tumorigenesis. The role of inflammation in regulation of breast cancer progression is not well established. Recently Mediator of IRF3 Activation (MITA) protein has been identified that regulates NF-κB and IFN pathways. Role of MITA in the context of inflammation and cancer progression has not been investigated. In the current report, we studied the role of MITA in the regulation of cross talk between cell death and inflammation in breast cancer cells. The expression of MITA was significantly lower on in estrogen receptor (ER) positive breast cancer cells than ER negative cells. Similarly, it was significantly down regulated in tumor tissue as compared to the normal tissue. The overexpression of MITA in MCF-7 and T47D decreases the cell proliferation and increases the cell death by activation of caspases. MITA positively regulates NF-κB transcription factor, which is essential for MITA induced cell death. The activation of NF-κB induces TNF-α production which further sensitizes MITA induced cell death by activation of death receptor pathway through capsase-8. MITA expression decreases the colony forming units and migration ability of MCF-7 cells. Thus, our finding suggests that MITA acts as a tumor suppressor which is down regulated during tumorigenesis providing survival advantage to tumor cell.

Indian Journal of Medical Research, 2016

Right ventricle (RV) functions predominantly as a volume pump that is resilient to adversities in... more Right ventricle (RV) functions predominantly as a volume pump that is resilient to adversities in various disease conditions 1. Function of RV depends on its own afterload, function of the left ventricle (LV) and contractility of the myocardium. It is established that the systolic function of RV is preserved even in clinically

Journal of cellular biochemistry, Aug 20, 2017

Inositol 1,4,5-trisphosphate receptors (IP3 Rs) regulate autophagy in normal cells and are associ... more Inositol 1,4,5-trisphosphate receptors (IP3 Rs) regulate autophagy in normal cells and are associated with metastasis in cancer cells. In breast cancer, however, the regulation and role of IP3 Rs is not clear. To study this we used MCF-7 breast cancer cell line and mouse model of breast cancer. Inhibiting IP3 R sub types resulted in compromised bioenergetics both in terms of glucose and mitochondrial metabolism. The siRNA mediated silencing of IP3 R or its blocking by its inhibitors Xestospongin C and 2-Amino-ethoxy diphenyl borate increased cell death and LC3II expression in MCF-7 cells as well as attenuated cellular bioenergetics. The level of Autophagy related gene, Atg5 was found to be up regulated after pharmacological as well as siRNA blocking of IP3 R. The specificity of its role in autophagy was confirmed through specific shRNA knockdown of the Atg5 along with IP3 R inhibitor. Inhibiting as well as silencing of IP3 R receptor also resulted in increase in ROS production which...

PloS one, 2017

1H NMR is used to detect alterations in metabolites and their linkage to metabolic processes in a... more 1H NMR is used to detect alterations in metabolites and their linkage to metabolic processes in a number of pathological conditions including breast cancer. Inositol 1, 4, 5 trisphosphate (IP3R) receptor is an intracellular calcium channel known to regulate metabolism and cellular bioenergetics. Its expression is up regulated in a number of cancers. However, its linkage to metabolism in disease conditions has not been evaluated. This study was designed to determine the association if any, of these metabolites with altered expression of IP3R in breast cancer. We used 1H NMR to identify metabolites in the serum of breast cancer patients (n = 27) and performed Real-time Polymerase Chain Reaction analysis for quantifying the expression of IP3R type 3 and type 2 in tissues from breast cancer patients (n = 40). Principal Component Analysis (PCA) and Partial Least Square-Discriminant Analysis (PLS-DA) clearly distinguished patients with high/low IP3R expression from healthy subjects. The p...

Nutrition and Cancer, 2016

Women consuming molecular iodine (I2) through seaweeds suffer the least from breast cancers. Zole... more Women consuming molecular iodine (I2) through seaweeds suffer the least from breast cancers. Zoledronate (Zol) is in clinical use for alleviation of bone pain in cancer patients. Triple negative breast cancers exhibit high mortality due to lack of neoadjuvant chemotherapy. I2 and Zol independently cause weak antiproliferative and apoptotic effect. So far, their combined effects have not been tested. We analyzed the effect of combination of I2 with Zol as a potent adjuvant therapeutic agent for triple negative breast cancer cells (MDA-MBA-231) and in the mice model of breast cancer. Cell viability, terminal deoxynucleotidyl transferase dUTP nick end labeling staining, Western blotting, real-time PCR, flow cytometry, and other assays were performed for assessing cell death, calcium levels, and migration potential, respectively, in treated cells. The increased caspase 8, increased [Ca(2+)]c levels, and endoplasmic reticulum (ER) stress resulted in apoptosis. Real time and fluorescence-based analysis demonstrated that the combination treatment targets ER Ca(2+) homeostasis chaperons leading to apoptosis. Combination therapy reduces metalloproteinases 2 and 9, inhibits invasion/migration of cells, and prevents growth of tumor in mice. I2 + Zol combination treatment induces synergistic increase in ER-mediated apoptosis, reduces invasion/migration potential of MDA-MB-231 cells, and exhibits antiproliferative property in vivo demonstrating its potential as combination therapy.

Current Cancer Drug Targets, Dec 29, 2014

Breast cancer is one of most common malignancies among women, represents nearly 30% of newly diag... more Breast cancer is one of most common malignancies among women, represents nearly 30% of newly diagnosed cancers every year. Till date, various therapeutic interventions including surgery, variety of chemotherapy, hormonal therapy, and radiotherapy are available and caused significant decline in the overall mortality rate. However therapeutic resistance, recurrence and lack of treatment in metastasis are the major challenges that need to be addressed. Increasing evidences suggests the presence of cancer stem cells (CSCs) in heterogeneous population of breast tumors capable of self- renewal and differentiation and thought to be responsible for the drug resistance and recurrence. Therefore compound that can target both differentiated cancer cell as well as the CSCs may provide a better treatment strategy. Dietary agents and natural health products are likely to be safe compared to deleterious side effect caused by chemotherapy, caught the attentions of investigators are now moving into clinical trials. This current review focuses on phytochemicals mainly flavonoids that are in use for breast cancer therapy in preclinical phase. As phytochemicals have several advantages on breast cancer and cancer stem cells it may provide scaffold to develop the new synthetic series for breast cancer therapy from analogues of most potent natural molecule via rational drug design approach.