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result(s) for
"Mehta, Sanjoy"
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Minor intron retention drives clonal hematopoietic disorders and diverse cancer predisposition
2021
Most eukaryotes harbor two distinct pre-mRNA splicing machineries: the major spliceosome, which removes >99% of introns, and the minor spliceosome, which removes rare, evolutionarily conserved introns. Although hypothesized to serve important regulatory functions, physiologic roles of the minor spliceosome are not well understood. For example, the minor spliceosome component ZRSR2 is subject to recurrent, leukemia-associated mutations, yet functional connections among minor introns, hematopoiesis and cancers are unclear. Here, we identify that impaired minor intron excision via ZRSR2 loss enhances hematopoietic stem cell self-renewal. CRISPR screens mimicking nonsense-mediated decay of minor intron-containing mRNA species converged on LZTR1, a regulator of RAS-related GTPases.
LZTR1
minor intron retention was also discovered in the RASopathy Noonan syndrome, due to intronic mutations disrupting splicing and diverse solid tumors. These data uncover minor intron recognition as a regulator of hematopoiesis, noncoding mutations within minor introns as potential cancer drivers and links among
ZRSR2
mutations, LZTR1 regulation and leukemias.
Loss of function of the minor spliceosome component ZRSR2 enhances hematopoietic stem cell self-renewal through minor intron retention of its target LZTR1, which is a regulator of RAS-related GTPases. Minor intron retention of LZTR1 was also identified in Noonan syndrome and diverse solid tumor types.
Journal Article
TP53 mutations and RNA-binding protein MUSASHI-2 drive resistance to PRMT5-targeted therapy in B-cell lymphoma
2022
To identify drivers of sensitivity and resistance to Protein Arginine Methyltransferase 5 (PRMT5) inhibition, we perform a genome-wide CRISPR/Cas9 screen. We identify
TP53
and RNA-binding protein
MUSASHI2
(
MSI2
) as the top-ranked sensitizer and driver of resistance to specific PRMT5i, GSK-591, respectively.
TP53
deletion and
TP53
R248W
mutation are biomarkers of resistance to GSK-591.
PRMT5
expression correlates with
MSI2
expression in lymphoma patients. MSI2 depletion and pharmacological inhibition using Ro 08-2750 (Ro) both synergize with GSK-591 to reduce cell growth. Ro reduces MSI2 binding to its global targets and dual treatment of Ro and PRMT5 inhibitors result in synergistic gene expression changes including cell cycle, P53 and MYC signatures. Dual MSI2 and PRMT5 inhibition further blocks c-MYC and BCL-2 translation. BCL-2 depletion or inhibition with venetoclax synergizes with a PRMT5 inhibitor by inducing reduced cell growth and apoptosis. Thus, we propose a therapeutic strategy in lymphoma that combines PRMT5 with MSI2 or BCL-2 inhibition.
Inhibition of the protein arginine methyltransferase PRMT5 has been suggested as a promising therapy for lymphoma. Here, the authors show that TP53 loss of function and
MUSASHI-2
(
MSI2
) expression are biomarkers of resistance to PRMT5-targeted therapy in B-cell lymphoma. Moreover, combining PRMT5 inhibition with MSI2 or BCL-2 inhibitors blocks the translation of key drivers of lymphoma, c-MYC and BCL-2, inhibiting cell growth.
Journal Article
CDC7 inhibition impairs neuroendocrine transformation in lung and prostate tumors through MYC degradation
by
Sabet, Amin
,
Linkov, Irina
,
Kawasaki, Kenta
in
692/4028/67/1059/153
,
692/4028/67/1612
,
692/4028/67/589
2024
Neuroendocrine (NE) transformation is a mechanism of resistance to targeted therapy in lung and prostate adenocarcinomas leading to poor prognosis. Up to date, even if patients at high risk of transformation can be identified by the occurrence of Tumor Protein P53 (
TP53)
and Retinoblastoma Transcriptional Corepressor 1
(RB1)
mutations in their tumors, no therapeutic strategies are available to prevent or delay histological transformation. Upregulation of the cell cycle kinase Cell Division Cycle 7 (CDC7) occurred in tumors during the initial steps of NE transformation, already after
TP53/RB1
co-inactivation, leading to induced sensitivity to the CDC7 inhibitor simurosertib. CDC7 inhibition suppressed NE transdifferentiation and extended response to targeted therapy in in vivo models of NE transformation by inducing the proteasome-mediated degradation of the MYC Proto-Oncogen (MYC), implicated in stemness and histological transformation. Ectopic overexpression of a degradation-resistant MYC isoform reestablished the NE transformation phenotype observed on targeted therapy, even in the presence of simurosertib. CDC7 inhibition also markedly extended response to standard cytotoxics (cisplatin, irinotecan) in lung and prostate small cell carcinoma models. These results nominate CDC7 inhibition as a therapeutic strategy to constrain lineage plasticity, as well as to effectively treat NE tumors de novo or after transformation. As simurosertib clinical efficacy trials are ongoing, this concept could be readily translated for patients at risk of transformation.
Journal Article
TNF-NFkB-p53 axis restricts in vivo survival of hPSC-derived dopamine neuron
2023
Ongoing, first-in-human clinical trials illustrate the feasibility and translational potential of human pluripotent stem cell (hPSC)-based cell therapies in Parkinson's disease (PD). However, a major unresolved challenge in the field is the extensive cell death following transplantation with <10% of grafted dopamine neurons surviving. Here, we performed a pooled CRISPR/Cas9 screen to enhance survival of postmitotic dopamine neurons
. We identified p53-mediated apoptotic cell death as major contributor to dopamine neuron loss and uncovered a causal link of TNFa-NFκB signaling in limiting cell survival. As a translationally applicable strategy to purify postmitotic dopamine neurons, we performed a cell surface marker screen that enabled purification without the need for genetic reporters. Combining cell sorting with adalimumab pretreatment, a clinically approved and widely used TNFa inhibitor, enabled efficient engraftment of postmitotic dopamine neurons leading to extensive re-innervation and functional recovery in a preclinical PD mouse model. Thus, transient TNFa inhibition presents a clinically relevant strategy to enhance survival and enable engraftment of postmitotic human PSC-derived dopamine neurons in PD.
CRISPR-Cas9 screen identifies p53 limiting survival of grafted human dopamine neurons. TNFα-NFκB pathway mediates p53-dependent human dopamine neuron deathCell surface marker screen to enrich human dopamine neurons for translational use. FDA approved TNF-alpha inhibitor rescues
dopamine neuron survival with
function.
Journal Article
Water quality assessment of a tropical river using water quality index (WQI), multivariate statistical techniques and GIS
by
Singh, Umesh Kumar
,
Mehta, Pankaj
,
Shil, Sanjoy
in
Bicarbonates
,
Carbonates
,
Geographical information systems
2019
Mahananda River is an important river in India and Bangladesh, as the people of both the countries use the water extensively, without sufficient and reliable information about water qualities and pollution status. The purpose of this study is to evaluate the water quality of the river and to analyse the suitability for drinking, agricultural and industrial uses. This is why this study on the Mahananda River is extremely important for the region. For this study, samples from fourteen sampling stations were collected in pre-monsoon and post-monsoon seasons in 2016 and water quality index (WQI), agriculture and industry-related indices were computed. WQI values designated two sampling stations out of fourteen sampling stations as ‘very bad’ category and another two sampling stations as ‘bad’ category. The pH values of some sampling stations slightly exceeded the upper permissible limit. USSL diagram analysis classified two samples of pre-monsoon season in C2S1 category which indicates a medium salinity and low sodium water. Magnesium hazard values of four sampling stations are above 50% suggesting not suitable for irrigation. However, some indices like sodium per cent, residual sodium carbonate and residual sodium bicarbonate, Kelly’s index, permeability index and potential salinity allow the water for use in irrigation purposes. Langelier Saturation Index and aggressive index values designate the water as moderately aggressive or non-aggressive. Ryznar Stability Index values designate the water as ‘aggressive’ or ‘very aggressive’ indicating unsuitability for industrial uses. Sampling stations S-1, S-2, S-8 and S-14 need special attention.
Journal Article
Hepatotropic viruses as etiological agents of acute liver failure and related-outcomes among children in India: a retrospective hospital-based study
2015
Background
Acute liver failure (ALF) is marked by a sudden loss of hepatic function and is associated with a high mortality rate in children. The etiology of ALF is shown to vary geographically. This study assessed the frequency of hepatotropic viruses as etiological agents of ALF in Indian children.
Methods
This retrospective study enrolled children aged 0–18 years with confirmed ALF admitted to Christian Medical College, Vellore and King Edward Memorial Hospital and Research Center, Pune between January 2003 and December 2005. The frequency of hepatotropic viruses as etiological agents in children with ALF aged ≤18 years was calculated with 95 % confidence interval (CI). Descriptive analyses of demographic characteristics, clinical signs and symptoms of ALF, choice of treatment and outcomes were performed.
Results
Of 76 children enrolled, 54 were included in the per-protocol analyses. Mean age of children with ALF was 5.43 years (standard deviation = 3.62); 51.9 % (28/54) were female. The percentage of children positive for anti-hepatitis A virus (HAV) IgM and hepatitis B surface antigen was 65.9 % (27/41; 95 % CI 49.4–79.9) and 15.9 % (7/44; 95 % CI 6.6–30.1), respectively. The final cause of ALF was HAV (36.3 %) followed by hepatitis B virus (HBV; 8.8 %). Before and during admission, encephalopathy was observed in 77.8 % (42/54) and 63.0 % (34/54) of children, respectively. A high number of children (46/54; 85.2 %) required intensive care and ALF was fatal in 24.1 % (13/54). The proportion of deaths due to HAV and HBV was 18.5 % (5/27) and 57.1 % (4/7), respectively.
Conclusions
HAV and HBV were the most common etiological agents of ALF in Indian children. Primary prevention by vaccination against HAV and HBV in young children may be useful in the prevention of ALF due to viral hepatitis in India.
Journal Article
Immunogenicity and safety of early vaccination with two doses of a combined measles-mumps-rubella-varicella vaccine in healthy Indian children from 9 months of age: a phase III, randomised, non-inferiority trial
by
Chatterjee, Sukanta
,
Povey, Michael
,
Mehta, Shailesh
in
Chicken pox
,
Chickenpox Vaccine - administration & dosage
,
Disease
2015
ObjectiveThis study (NCT00969436) compared the immunogenicity and safety of measles-mumps-rubella (MMR) followed by MMR+varicella (V) vaccines to (1) 2 doses of combined MMRV and (2) MMR followed by MMRV, in Indian children.DesignPhase III, open, randomised, non-inferiority study.Setting6 tertiary care hospitals located in India.ParticipantsHealthy participants aged 9–10 months not previously vaccinated against/exposed to measles, mumps, rubella and varicella or without a history of these diseases.InterventionsParticipants were randomised (2:2:1) to receive 2 doses of either MMRV (MMRV/MMRV group) or MMR followed by MMRV (MMR/MMRV group) or MMR followed by MMR+V (MMR/MMR+V, control group) at 9 and 15 months of age. Antibody titres against measles, mumps and rubella were measured using ELISA and against varicella using an immunofluorescence assay.Main outcome measuresTo demonstrate non-inferiority of the 2 vaccination regimens versus the control in terms of seroconversion rates, defined as a group difference with a lower bound of the 95% CI >−10% for each antigen, 43 days postdose 2. Parents/guardians recorded solicited local and general symptoms for a 4-day and 43-day period after each vaccine dose, respectively.ResultsSeroconversion rates postdose 1 ranged from 87.5% to 93.2% for measles, 83.3% to 86.1% for mumps and 98.7% to 100% for rubella across the 3 vaccine groups. The seroconversion rates postdose 2 were 100% for measles, mumps and rubella and at least 95.8% for varicella across the 3 vaccine groups. Non-inferiority of MMRV/MMRV and MMR/MMRV to MMR/MMR+V was achieved for all antigens, 43 days postdose 2. The 3 vaccination regimens were generally well tolerated in terms of solicited local and general symptoms.ConclusionsThe immune responses elicited by the MMRV/MMRV and MMR/MMRV vaccination regimens were non-inferior to those elicited by the MMR/MMR+V regimen for all antigens. The 3 vaccination schedules also exhibited an acceptable safety profile in Indian children.Trial registration numberNCT00969436.
Journal Article
Human papillomavirus prevalence and type-distribution in women with cervical lesions: a cross-sectional study in Sri Lanka
by
Karunaratne, Kanishka
,
Mehta, Shailesh
,
Molijn, Anco
in
Adult
,
Biomedical and Life Sciences
,
Biomedicine
2014
Background
Cervical cancer ranks second among all cancers reported in Sri Lankan women. This study assessed the prevalence and type-distribution of human papillomavirus (HPV) among Sri Lankan women with invasive cervical cancer (ICC) and pre-cancerous lesions.
Methods
114 women aged 21 years and above, hospitalized in the National Cancer Institute, Sri Lanka with a diagnosis of ICC or cervical intraepithelial neoplasia (CIN) 2/3 were prospectively enrolled between October 2009 and September 2010 (110430/NCT01221987). The cervical biopsy or excision specimens collected during routine clinical procedures were subjected to histopathological review. DNA was extracted from samples with a confirmed histological diagnosis and was amplified using polymerase chain reaction and HPV DNA was detected using Enzyme Immuno Assay. HPV positive samples were typed using reverse hybridization Line Probe Assay.
Results
Of the cervical samples collected, 93.0% (106/114) had a histologically confirmed diagnosis of either ICC (98/106) or CIN 2/3 (8/106). Among all ICC cases, squamous cell carcinoma was diagnosed in the majority of women (81.6% [80/98]). HPV prevalence among ICC cases was 84.7% (83/98). The HPV types most commonly detected in ICC cases with single HPV infection (98.8% [82/83]) were HPV-16 (67.3%) and HPV-18 (9.2%). Infection with multiple HPV types was recorded in a single case (co-infection of HPV-16 and HPV-59).
Conclusions
HPV was prevalent in most women with ICC in Sri Lanka; HPV-16 and HPV-18 were the predominantly detected HPV types. An effective prophylactic vaccine against the most prevalent HPV types may help to reduce the burden of ICC disease.
Journal Article