Biology subjects

Datta, J.

Publications and source records attributed to Datta, J..

5 recordsLinked to original sources

bioRxiv2022

Activity of Estrogen Receptor β Agonists in Therapy-Resistant Estrogen Receptor-Positive Breast Cancer

BackgroundAmong women, breast cancer is the leading cause of cancer-related death worldwide. Estrogen receptor positive (ER+) breast cancer accounts for 70% of all breast cancer subtypes. Although ER+ breast cancer initially responds to estrogen deprivation or blockade, resistance emergence compelling the use of more aggressive therapies. While ER is a driver in ER+ breast cancer, ER{beta} plays an inhibitory role in several different cancer types. To date, the lack of highly selective ER{beta} agonists without ER activity has limited the exploration of ER{beta} activation as a strategy for ER+ breast cancer. MethodsWe measured expression levels of ESR1 and ESR2 genes in immortalized mammary epithelial cells and different breast cancer cell lines. The viability of ER+ breast cancer cell lines upon treatments with specific ER{beta} agonists, including OSU-ERb-12 and LY500307 was assessed. The specificity of the ER{beta} agonists, OSU-ERb-12 and LY500307, was confirmed by reporter assays. The effects of the agonists on cell proliferation, cell cycle, apoptosis, colony formation, cell migration, and expression of tumor suppressor proteins were analyzed. The expression of ESR2 and genes containing ERE-AP1 composite response elements was examined in ER+ human breast cancer samples to determine the correlation between ESR2 expression and overall survival and that of putative ESR2 regulated genes. ResultsIn this study, we demonstrate the efficacy of highly selective ER{beta} agonists in ER+ breast cancer cell lines and drug-resistant derivatives. ER{beta} agonists blocked cell proliferation, migration and colony formation; and induced apoptosis and S and/or G2/M cell cycle arrest of ER+ breast cancer cell lines. Also, increases in the expression of the key tumor suppressors FOXO1 and FOXO3a were noted. Importantly, the strong synergy between ER{beta} agonists and ER antagonists suggested that the efficacy of ER{beta} agonists is maximized by combination with ER blockade. Lastly, ESR2 (ER{beta} gene) expression was negatively correlated with ESR1 (ER gene) and CCND1 RNA expression in human metastatic ER+/HER2-breast cancer samples. ConclusionOur results demonstrate that highly selective ER{beta} agonists attenuate the viability of ER+ breast cancer cell lines in vitro and suggest that this therapeutic strategy merits further evaluation for ER+ breast cancer.

cancer biology↗

bioRxiv2022

Augmentation of extracellular ATP synergizes with chemotherapy in triple negative breast cancer

IntroductionBreast cancer affects two million women worldwide every year and is the most common cause of cancer-related death among women. The triple-negative breast cancer (TNBC) sub-type is associated with an especially poor prognosis because currently available therapies, fail to induce long-lasting responses. Therefore, there is an urgent need to develop novel therapies that result in durable responses. One universal characteristic of the tumor microenvironment is a markedly elevated concentration of extracellular adenosine triphosphate (eATP). Chemotherapy exposure results in further increases in eATP through its release into the extracellular space of cancer cells via P2RX channels. eATP levels are reduced by eATPases. Given that high concentrations of eATP are cytotoxic, we hypothesized that augmenting the release of eATP through P2RX channels and inhibiting extracellular ATPases would sensitize TNBC cells to chemotherapy. MethodsTNBC cell lines MDA-MB 231, Hs 578t and MDA-MB 468 and non-tumorigenic immortalized mammary epithelial MCF-10A cells were treated with increasing concentrations the chemotherapeutic agent paclitaxel in the presence of eATPase inhibitors, specific agonists or antagonists of P2RXs with cell viability and eATP content being measured. Additionally, the mRNA, protein and cell surface expressions of the purinergic receptors P2RX4 and P2RX7 were evaluated in all examined cell lines via qRT-PCR, western blot, and flow cytometry analyses, respectively. ResultsIn the present study, we observed dose-dependent declines in cell viability and increases in eATP in paclitaxel-treated TNBC cell lines in the presence of inhibitors of eATPases. These effects were reversed by specific antagonists of P2RXs. Similar results were observed with P2RX activators. All examined cell lines expressed both P2RX4 and P2RX7 at the mRNA, protein and cell surface levels. ConclusionThese results reveal that eATP modulates the chemotherapeutic response in TNBC cell lines which could be exploited to enhance the efficacy of chemotherapy regimens for TNBC.

cancer biology↗

bioRxiv2021

Combined MEK and STAT3 inhibition reprograms the tumor microenvironment to overcome immunotherapy resistance in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is characterized by immune exclusion, pro-inflammatory polarization of cancer-associated fibroblasts (CAF), and resistance to immune checkpoint inhibition (ICI). We have previously demonstrated that reciprocally activated RAS/MEK/ERK and JAK/STAT3 pathways mediate therapeutic resistance, while combined MEK and STAT3 inhibition (MEKi+STAT3i) overcomes such resistance in preclinical models. We now show that combined MEKi+STAT3i not only alters stromal architecture but also uncovers stromal plasticity by revealing a substantial attenuation of Il6/Cxcl1-expressing secretory and Lrrc15-expressing myofibroblastic CAF phenotypes with a concomitant enrichment of Ly6a/Cd34-expressing CAF phenotypes exhibiting mesenchymal progenitor-like properties via single-cell RNA sequencing in Ptf1acre/+;LSL-KrasG12D/+;Tgfbr2flox/flox(PKT) mice. This remodeling of CAF heterogeneity is associated with reprogramming of immunosuppressive myeloid populations and enhanced trafficking of CD8+ T-cells which exhibit a distinct effector transcriptional program. These MEKi+STAT3i-mediated repercussions are in part CAF-dependent, since CRISPR/Cas9 genetic silencing of CAF-restricted Mek1/Stat3 mitigates inflammatory CAF polarization and myeloid infiltration in vivo. Addition of MEKi+STAT3i to PD-1 blockade overcomes ICI resistance by significantly augmenting anti-tumor responses and dramatically improving survival in PKT mice compared with anti-PD-1 monotherapy. The addition of MEKi+STAT3i to PD-1 blockade not only augments the recruitment of activated and memory T-cell populations, but also improves their degranulating capacity and functional cytotoxicity compared to PD-1 blockade alone. Importantly, treatment of a patient with chemotherapy-refractory metastatic PDAC with MEKi (Trametinib), STAT3i (Ruxolitinib), and PD-1 inhibitor (Nivolumab) was well-tolerated and yielded clinical benefit. These data uncover a novel paradigm in which combined MEKi+STAT3i reprograms stromal inflammation and immune tolerance to overcome immunotherapy resistance in PDAC.

cancer biology↗

bioRxiv2021

A study of Mutation in ATP7B gene and its correlation with clinical phenotype and radiological features in Wilson Disease patients

IntroductionWilson Disease (WD) is an autosomal recessive disease caused by mutations in the ATP7B gene. Clinical manifestations of WD are variable. Identification of prevalent mutations in a given population is necessary to provide mutation-based molecular diagnosis. Previous studies have detected common mutations in this part of the world and our study aimed to correlate genotype with clinical and radiological features. MethodsA descriptive cross-sectional observational study was conducted over a period of two years in a tertiary care hospital and neurology referral unit of Kolkata, India. All WD patients within the study period and meeting the inclusion criteria were included. Demographic data collection, clinical examination and relevant laboratory investigations were done. Magnetic resonance imaging of brain and cognitive assessment by Mini Mental Score Exam (MMSE) were also performed. Blood was collected for genetic analyses. PCR-Sanger sequencing of exons 2,4,6,8,10,14,16,18 of ATP7B gene was done based on previous reports of mutation hotspots of ATP7B gene for WD in Eastern India. Genotype phenotype correlation was attempted using two supervised machine learning methods, viz. logistic regression with an elastic-net penalty and the random forest. ResultsOf 52 WD patients were included in the study, 57.7% were males. The mean age at diagnosis was 13.96 years. Majority (61.8%) of the patients had dystonia on presentation, followed by dysarthria (41.2%), tremor (17.6%) and ataxia (11.8%). The mean MMSE and Frontal Assessment Battery score were 23.74 and 10.63 respectively and both were lower than the normal baseline values.Out of the total cohort of 52 patients,15(28.8%) harbored previously reported common mutations from this part of the country. Of the 15, 12 had the same mutation of c.813C>A(p.cys271Ter).The presence of common mutationswas associated with several distinct clinical phenotypes in the mathematical models but larger sample sizes are needed to corroborate the correlation. ConclusionsWD patients in eastern India have significant genotypic and phenotypic diversity. Further studies with larger samples and screening of remaining exons are warranted.

neuroscience↗

bioRxiv2021

Diet induced hyperlipidemia confers resistance to standard therapy in pancreatic cancer by selecting for "tumor protective" microbial metabolites and treatment refractory cells.

Obesity causes a number of systemic alterations including chronic inflammation and changes in gut microbiome. However, whether these actively contribute to poor survival and therapy resistance in patients with pancreatic cancer remain undetermined. Our current study shows that high fat diet fed pancreatic tumor bearing mice do not respond to standard of care therapy with gemcitabine and paclitaxel when compared to corresponding control diet fed mice. Upon fecal matter transplant from control mice to high fat diet fed mice, the tumors became sensitive to standard of care therapy and showed extensive cell death. Analysis of gut microbiome showed an enrichment of queuosine (Q) producing bacteria in high fat diet fed mice and an enrichment of S-adenosyl methionine (SAM) producing bacteria in control diet fed mice. Further, treatment of high fat diet fed animals with SAM recapitulated the observation with lean to obese fecal matter transplant. Additionally, treatment of pancreatic and colon cancer cell lines in vitro with Q promoted resistance to the paclitaxel and oxaliplatin respectively, while treatment with SAM promoted sensitivity to these drugs. Treatment of pancreatic cancer cells with Q showed upregulation PRDX1, that is involved in oxidative stress protection. Analysis of tumor tissues in high fat diet fed mice showed high PRDX1, low apoptosis and increased proliferation, which were reversed upon treatment with SAM as well as by lean to obese fecal matter transplant. In parallel, high fat diet fed mice showed increase in CD133+ treatment refractory population compared to the control animals. Interestingly, treatment with Q in vitro did not enrich for CD133+ population, indicating that Q mediated protection from cell death was independent of enrichment of treatment refractory cells. These observations indicated that microbial metabolite Q accumulated in high fat diet fed mice protected tumors from chemotherapy induced oxidative stress by upregulating PRDX1. This protection could be reversed by treatment with SAM. We conclude that relative concentration of S-adenosyl methionine and queuosine in fecal samples of pancreatic cancer patients can be indicative of therapy response in this disease.

cancer biology↗