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1.
Sci Adv ; 10(12): eadn4649, 2024 Mar 22.
Article in English | MEDLINE | ID: mdl-38517960

ABSTRACT

Genomic rearrangements are a hallmark of most childhood tumors, including medulloblastoma, one of the most common brain tumors in children, but their causes remain largely unknown. Here, we show that PiggyBac transposable element derived 5 (Pgbd5) promotes tumor development in multiple developmentally accurate mouse models of Sonic Hedgehog (SHH) medulloblastoma. Most Pgbd5-deficient mice do not develop tumors, while maintaining normal cerebellar development. Ectopic activation of SHH signaling is sufficient to enforce cerebellar granule cell progenitor-like cell states, which exhibit Pgbd5-dependent expression of distinct DNA repair and neurodevelopmental factors. Mouse medulloblastomas expressing Pgbd5 have increased numbers of somatic structural DNA rearrangements, some of which carry PGBD5-specific sequences at their breakpoints. Similar sequence breakpoints recurrently affect somatic DNA rearrangements of known tumor suppressors and oncogenes in medulloblastomas in 329 children. This identifies PGBD5 as a medulloblastoma mutator and provides a genetic mechanism for the generation of oncogenic DNA rearrangements in childhood cancer.


Subject(s)
Cerebellar Neoplasms , Medulloblastoma , Humans , Child , Animals , Mice , Medulloblastoma/genetics , Transposases/genetics , Transposases/metabolism , Hedgehog Proteins/metabolism , Transcription Factors/genetics , Mutagenesis , Cerebellar Neoplasms/genetics
2.
SAGE Open Med Case Rep ; 11: 2050313X231188883, 2023.
Article in English | MEDLINE | ID: mdl-37529081

ABSTRACT

The fat mass and obesity-associated gene (FTO) codes for a DNA/RNA demethylase. Pathological variants in this gene are rare, with only three reports in the literature, all with mutations in the catalytic domain. We report the first biallelic human variant in fat mass and obesity-associated gene (c.287G>C, p.Arg96Pro/R96P) outside the catalytic site, causing numerous abnormalities across multiple organ systems, affecting respiratory, cardiovascular, and neurological function. Biochemical assays of cells with the patient's variant were performed to further quantify the effect of the variant on function. Loss-of-function resulting from the patient's R96P missense variant was demonstrated with in vitro biochemical characterization of demethylase activity, resulting in a 90% reduction in function of the fat mass and obesity-associated protein compared to wild-type. Our findings demonstrate a novel fat mass and obesity-associated gene non-catalytic site variant with a unique patient phenotype of bilateral multifocal epilepsy and multisystem congenital anomalies.

3.
J Thromb Thrombolysis ; 56(1): 164-174, 2023 Jul.
Article in English | MEDLINE | ID: mdl-37097552

ABSTRACT

Anticoagulation during Impella® support is a challenge due to its complications and inconsistent practice across the globe. This observational, retrospective chart review included all patients with Impella® support at our advanced cardiac center at a quaternary care hospital in the Middle East gulf region. The study was conducted over six years (2016-2022), a time period during which manufacturer recommendations for purge solution, anticoagulation protocols as well as Impella® place in therapy and utilization were all evolving. We aimed to evaluate the efficacy of different anticoagulation practices and association with complications and outcomes. Forty-one patients underwent Impella® during the study period, including 25 patients with support for more than 12 h, and are the focus of our analysis. Cardiogenic shock (n = 25, 60.9%) was the primary indication for Impella®, followed by facilitating high-risk PCI (n = 15, 36.7%) and left ventricular afterload reduction in patients undergoing veno-arterial extracorporeal membrane oxygenation (n = 1, 2.4%). Our overall Impella® usage evolved over the years from a primary use to facilitate a high-risk PCI to the recent more common use of LV unloading in cardiogenic shock. No patients experienced device malfunction and the incidence of other complications including ischemic stroke and bleeding were comparable to those reported in the literature (12.2% and 24% respectively). The 30-day all-cause mortality of 41 patients was 53.6%. In line with the evolving recommendations and evidence, we observed an underutilization of non-heparin-based purge solutions and inconsistent management of anticoagulation in the setting of both Impella® and VA ECMO which necessitates more education and protocols.


Subject(s)
Heart-Assist Devices , Percutaneous Coronary Intervention , Humans , Anticoagulants/adverse effects , Blood Coagulation , Heart-Assist Devices/adverse effects , Retrospective Studies , Shock, Cardiogenic/therapy , Treatment Outcome
4.
Nat Mater ; 22(3): 391-399, 2023 03.
Article in English | MEDLINE | ID: mdl-36864161

ABSTRACT

Medulloblastoma is the most common malignant paediatric brain tumour, with ~30% mediated by Sonic hedgehog signalling. Vismodegib-mediated inhibition of the Sonic hedgehog effector Smoothened inhibits tumour growth but causes growth plate fusion at effective doses. Here, we report a nanotherapeutic approach targeting endothelial tumour vasculature to enhance blood-brain barrier crossing. We use fucoidan-based nanocarriers targeting endothelial P-selectin to induce caveolin-1-dependent transcytosis and thus nanocarrier transport into the brain tumour microenvironment in a selective and active manner, the efficiency of which is increased by radiation treatment. In a Sonic hedgehog medulloblastoma animal model, fucoidan-based nanoparticles encapsulating vismodegib exhibit a striking efficacy and marked reduced bone toxicity and drug exposure to healthy brain tissue. Overall, these findings demonstrate a potent strategy for targeted intracranial pharmacodelivery that overcomes the restrictive blood-brain barrier to achieve enhanced tumour-selective penetration and has therapeutic implications for diseases within the central nervous system.


Subject(s)
Cerebellar Neoplasms , Medulloblastoma , Animals , Hedgehog Proteins , Blood-Brain Barrier , Caveolin 1 , P-Selectin , Transcytosis , Tumor Microenvironment
5.
Perfusion ; : 2676591221144729, 2022 Dec 09.
Article in English | MEDLINE | ID: mdl-36484202

ABSTRACT

We describe a case series of five pregnant or postpartum women with severe CoViD-19-related ARDS requiring VV ECMO at our centre between Jan 1 and Sep 30, 2021. All patients were cannulated at the referring hospitals by our team before transferring to our centre. None of the women were vaccinated against CoViD-19. All had severe ARDS with Murray's Lung Injury Score of 3-4 and met the severity threshold for ECMO initiation that was used in the EOLIA study. All patients were discharged alive to home, acute rehabilitation, or lung transplant centre. One patient suffered intrauterine death before ECMO initiation and another while on ECMO. VV ECMO for refractory CoViD-19 related ARDS in the peripartum period is safe, and in this small series, it was associated with good maternal survival rates.

6.
Acta Neuropathol Commun ; 10(1): 47, 2022 04 08.
Article in English | MEDLINE | ID: mdl-35395831

ABSTRACT

Pediatric high-grade gliomas, specifically diffuse midline gliomas, account for only 20% of clinical cases but are 100% fatal. A majority of the DMG cases are characterized by the signature K27M mutation in histone H3. The H3K27M mutation opposes the function of enhancer of zeste homolog 2 (EZH2), the methyltransferase enzyme of the polycomb repressor complex 2. However, the role of EZH2 in DMG pathogenesis is unclear. In this study, we demonstrate a tumor suppressor function for EZH2 using Ezh2 loss- and gain-of-function studies in H3WT DMG mouse models. Genetic ablation of Ezh2 increased cell proliferation and tumor grade while expression of an Ezh2 gain-of-function mutation significantly reduced tumor incidence and increased tumor latency. Transcriptomic analysis revealed that Ezh2 deletion upregulates an inflammatory response with upregulation of immunoproteasome genes such as Psmb8, Psmb9, and Psmb10. Ezh2 gain-of-function resulted in enrichment of the oxidative phosphorylation/mitochondrial metabolic pathway namely the isocitrate dehydrogenase Idh1/2/3 genes. Pharmacological inhibition of EZH2 augmented neural progenitor cell proliferation, supporting the tumor suppressive role of EZH2. In vivo 7-day treatment of H3K27M DMG tumor bearing mice with an EZH2 inhibitor, Tazemetostat, did not alter proliferation or significantly impact survival. Together our results suggest that EZH2 has a tumor suppressor function in DMG and warrants caution in clinical translation of EZH2 inhibitors to treat patients with DMG.


Subject(s)
Brain Neoplasms , Enhancer of Zeste Homolog 2 Protein , Glioma , Animals , Brain Neoplasms/pathology , Enhancer of Zeste Homolog 2 Protein/genetics , Glioma/genetics , Histones/genetics , Humans , Mice , Mutation , Proteasome Endopeptidase Complex/genetics
7.
J Hypertens ; 39(11): 2183-2189, 2021 11 01.
Article in English | MEDLINE | ID: mdl-34620808

ABSTRACT

BACKGROUND: Stroke is an important neurological disorder with significant morbidity and mortality. In India, the risk factors for stroke (obesity, diabetes mellitus, alcoholism, hypertension, and sedentary lifestyle) are mounting with economic growth and increasing the disease burden. OBJECTIVE: To assess the severity and risk factors of stroke in India and identify any new predisposing factors. METHODS: A multicentric (six tertiary care hospitals across India) prospective observational study (from September 2016 to July 2017) was conducted on 526 stroke patients, presenting within the first 24 h to examine the risk factors for ischemic and hemorrhagic strokes. Severity was determined using the National Institutes of Health Stroke Scale (NIHSS). RESULTS: Predominantly male (72.3%), 75% of the sample was >50 years old, with a mean body mass index (BMI) of 25.8 ±â€Š4.3 kg/m2 and 14.6% obese patients. Hypertension and diabetes mellitus were the commonest comorbidities, followed by a history of ischemic heart disease and familial history of stroke. 20.5% of patients had mild strokes, 57.4% had moderate, 8.4% experienced moderate-severe strokes, whereas 7.2% had severe strokes. Regarding the admission diagnoses, 56.8% were ischemic, 18.6% were hemorrhagic, 1.1% had a transient ischemic attack, 6.6% suffered recurrent strokes, and 17% were other forms. CONCLUSION: The foremost risk factors for stroke in India, hypertension and diabetes, need to be controlled and treated like other global high-risk populations for stroke prevention. The NIHSS scores highlight the relationship between risk factors and stroke severity.


Subject(s)
Brain Ischemia , Ischemic Attack, Transient , Stroke , Brain Ischemia/epidemiology , Brain Ischemia/etiology , Humans , India/epidemiology , Male , Middle Aged , Prospective Studies , Risk Factors , Severity of Illness Index , Stroke/epidemiology , Stroke/etiology
8.
Am J Med Sci ; 362(6): 546-552, 2021 12.
Article in English | MEDLINE | ID: mdl-34161828

ABSTRACT

BACKGROUND: The current gold standard for blood pressure (BP) measurements is based on office BP measurements (OBPMs) by a sphygmomanometer or a digital device. Ambulatory BP measurement (ABPM) is a noninvasive method for continuous monitoring of BP over a period during routine activities of the patient. Thus, ABPM offers multiple BP readings during the patients' daily routine as compared to the single reading by OBPM at rest. A good correlation exists between mean 24-hour BP readings and the prediction of cardiovascular events. The present multicenter observational study was aimed to assess the correlation between ABPM and OBPM in patients with newly diagnosed, controlled, or uncontrolled hypertension in the community setting. Our hypothesis was to test if ABPM provides any further value in those hypertensive patients in whom the office blood pressure levels are controlled. A supplementary hypothesis was whether obtaining ABPM in patients with newly diagnosed or uncontrolled hypertension yields any value over and beyond OBPM. Another objective was to find out the applicability of ABPM in the community setting where the medical care is provided by primary care family physicians and not by specialists. MATERIALS AND METHODS: Materials and Methods A total of 1000 patients were analysed for this study. Those with controlled hypertension were assigned to Group A, and those with newly diagnosed/untreated hypertension comprised Group B. Group A was followed up during Visit 2 and Group B was followed up during Visit 2 and either Visit 3 or Visit 4 to assess the BP measurements by ABPM and OBPM. RESULTS: The correlation between ABPM and OBPM showed minimal variation in the BP readings of Group A subjects at Visit 2. A variation in BP readings was observed in Group B at Visit 2. Furthermore, the correlation was established between ABPM and OBPM noted for Group B subjects during Visit 3, and minimal variation was noted during Visit 4. CONCLUSIONS: Conclusions A good correlation was observed between ABPM and OBPM during both visits in patients in Groups A and B. However, a notable variation was noted in the diastolic BP readings. Thus, large-scale clinical studies are required to detect the prevalence of hypertension, masked hypertension, and dipping patterns associated with hypertension and other related medical co-morbidities.


Subject(s)
Hypertension , Masked Hypertension , Blood Pressure/physiology , Blood Pressure Determination , Blood Pressure Monitoring, Ambulatory/methods , Humans , Hypertension/drug therapy , Masked Hypertension/diagnosis , Masked Hypertension/drug therapy , Masked Hypertension/epidemiology
9.
Phys Chem Chem Phys ; 22(47): 27861-27872, 2020 Dec 16.
Article in English | MEDLINE | ID: mdl-33284302

ABSTRACT

This work reports a systematic study of the evolution of charge transport properties in granular ultra-thin films of palladium of thicknesses varying between 6 nm and 2 nm. While the films with thickness >4 nm exhibit metallic behaviour, that at 3 nm thickness undergoes a metal-insulator transition at 19.5 K. In contrast, the 2 nm thick film remained insulating at all temperatures, with transport following Mott's variable range hopping. At room temperature, while the thicker films exhibit resistance decrease upon H2 exposure, the insulating film showed an anomalous initial resistance increase before switching to a subsequent decrease. The nanostructure dependent transport and the ensuing H2 response is modeled on a percolation model, which also explores the relevance of film thickness as a macroscopic control parameter to engineer the desired system response in granular metal films.

10.
Indian J Crit Care Med ; 24(8): 630-642, 2020 Aug.
Article in English | MEDLINE | ID: mdl-33024367

ABSTRACT

The coronavirus disease (COVID-19) pandemic has affected nearly all nations globally. The highly contagious nature of the disease puts the healthcare workers at high risk of acquiring infection, especially while handling airway and performing aerosol-generating procedures. The Indian Society of Critical Care Medicine, through this position paper, aims to provide guidance for safe airway management to all healthcare workers dealing with airway in COVID-19 patients. HOW TO CITE THIS ARTICLE: Praveen Kumar G, Kulkarni AP, Govil D, Dixit SB, Chaudhry D, Samavedam S, et al. Airway Management and Related Procedures in Critically Ill COVID-19 Patients: Position Statement of the Indian Society of Critical Care Medicine. Indian J Crit Care Med 2020;24(8):630-642.

11.
Cell ; 182(4): 1044-1061.e18, 2020 08 20.
Article in English | MEDLINE | ID: mdl-32795414

ABSTRACT

There is an unmet clinical need for improved tissue and liquid biopsy tools for cancer detection. We investigated the proteomic profile of extracellular vesicles and particles (EVPs) in 426 human samples from tissue explants (TEs), plasma, and other bodily fluids. Among traditional exosome markers, CD9, HSPA8, ALIX, and HSP90AB1 represent pan-EVP markers, while ACTB, MSN, and RAP1B are novel pan-EVP markers. To confirm that EVPs are ideal diagnostic tools, we analyzed proteomes of TE- (n = 151) and plasma-derived (n = 120) EVPs. Comparison of TE EVPs identified proteins (e.g., VCAN, TNC, and THBS2) that distinguish tumors from normal tissues with 90% sensitivity/94% specificity. Machine-learning classification of plasma-derived EVP cargo, including immunoglobulins, revealed 95% sensitivity/90% specificity in detecting cancer. Finally, we defined a panel of tumor-type-specific EVP proteins in TEs and plasma, which can classify tumors of unknown primary origin. Thus, EVP proteins can serve as reliable biomarkers for cancer detection and determining cancer type.


Subject(s)
Biomarkers, Tumor/metabolism , Extracellular Vesicles/metabolism , Neoplasms/diagnosis , Animals , Biomarkers, Tumor/blood , Cell Line , HSC70 Heat-Shock Proteins/metabolism , Humans , Machine Learning , Mice , Mice, Inbred C57BL , Microfilament Proteins/metabolism , Neoplasms/metabolism , Proteome/analysis , Proteome/metabolism , Proteomics/methods , Sensitivity and Specificity , Tetraspanin 29/metabolism , rap GTP-Binding Proteins/metabolism
12.
Indian J Crit Care Med ; 24(Suppl 3): S117-S121, 2020 Apr.
Article in English | MEDLINE | ID: mdl-32704217

ABSTRACT

How to cite this article: Govil D, Kumar GP. Extracorporeal Therapy in Sepsis. Indian J Crit Care Med 2020;24(Suppl 3):S117-S121.

13.
Indian J Crit Care Med ; 24(3): 153-154, 2020 Mar.
Article in English | MEDLINE | ID: mdl-32435091

ABSTRACT

How to cite this article: Govil D, Kumar GP. Know Thy Ulcers!!! Indian J Crit Care Med 2020;24(3):153-154.

14.
Int J Biol Macromol ; 136: 395-403, 2019 Sep 01.
Article in English | MEDLINE | ID: mdl-31173829

ABSTRACT

The increasing acceptance of ready to eat food generates demand on development of active and intelligent food packaging material. Even though many polymers have been used for the packaging, they have limitations for broad applications. Among the various polymers, Poly Vinyl Alcohol is a promising film forming polymer with highly flexible, emulsifying and adhesive properties. A variety of nano-fabrication techniques have already been reported to improve the mechanical and antimicrobial properties of PVA to exploit its wider applications. In the present study, starch-PVA based composite films incorporated with zinc oxide nanoparticles and phytochemicals were prepared by solvent casting technique. The films were characterized by XRD, FT-IR, UV-Vis spectrometry and SEM. The developed nanocomposite films were demonstrated to have enhanced water barrier, mechanical and antimicrobial properties. The unique features of the nanocomposite with its pH indication property demonstrated in the study indicate its potential usage in food packaging applications.


Subject(s)
Food Packaging/methods , Nanoparticles/chemistry , Phytochemicals/chemistry , Plant Extracts/chemistry , Polyvinyl Alcohol/chemistry , Starch/chemistry , Zinc Oxide/chemistry , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacology , Hydrogen-Ion Concentration , Mechanical Phenomena , Myristica/chemistry , Nanocomposites/chemistry , Solvents/chemistry , Syzygium/chemistry , Water/chemistry
15.
J Thyroid Res ; 2018: 8253094, 2018.
Article in English | MEDLINE | ID: mdl-29854383

ABSTRACT

INTRODUCTION: Thyroidectomy is now a less popular therapeutic option for Graves' disease. The frequency of thyroid nodule and the cancer risk of these nodules accompanying Graves' disease are controversial. The outcome of thyroid cancers coexisting with Graves' disease is debated. STUDY DESIGN: Designed as retrospective case control study of papillary thyroid cancers associated with Graves' disease and those with euthyroid background. Pathological characteristics and outcome of papillary thyroid cancers in the two groups were compared. RESULTS: The tumour characteristics did not differ significantly in the groups. The patients were followed for a mean period of 77.32 months and found significant incidences of disease progression in patients with papillary thyroid cancer associated with Graves' disease (p = 0.034; OR 2.747, CI 1.078-7.004). Disease progression as new distant metastases mostly in skeletal locations was high in this group compared to euthyroid group (p = 0.027; OR 4.121, CI 1.008-15.600). There was higher incidence of cumulative metastatic diseases in papillary thyroid cancer associated with Graves' disease. CONCLUSION: Papillary thyroid cancers associated with Graves' disease show aggressive biological behaviour and favoured site of distant metastases was osseous locations. Early diagnosis by routine screening of Graves' disease patients with ultrasound imaging and aspiration studies is recommended.

16.
Sci Rep ; 8(1): 5058, 2018 03 22.
Article in English | MEDLINE | ID: mdl-29568048

ABSTRACT

We put forth our opinion regarding the enhanced plasticity and modulation of mechanical properties of polymeric films obtained through electrospinning process in this article. In majority of the pharmaceutical, biomedical, and packaging applications, it is desirable that polymer based matrices should be soft, flexible, and have a moderate toughness. In order to convert inflexible and brittle polymers, adjuvants in the form of plasticizers are added to improve the flexibility and smoothness of solvent casted polymer films. However, many of these plasticizers are under scrutiny for their toxic effects and environmental hazards. In addition, plasticizers also increase the cost of end products. This has motivated the scientific community to investigate alternate approaches. The changes imparted in membrane casted by electrospinning were tried to be proved by SEM, Mechanical property study, DSC and XRD studies. We have showed dramatic improvement in flexibility of poly(ε-caprolactone) based nanofiber matrix prepared by electrospinning method whereas solvent casting method without any plasticizer produced very brittle, inflexible film of PCL. Modulation capacity of mechanical properties is also recorded. We tried to support our opinion by citing several similar findings available in the open literature. The electrospinning method helps in plasticization and in tuning mechanical properties.

17.
Nurs J India ; 107(1): 30-32, 2016 Jan.
Article in English | MEDLINE | ID: mdl-30351770

ABSTRACT

Pain during areteriovenous fistula (AVF) cannulation remains a common problem in haemodialysis (HD) patients.This study was undertaken to assess the effect of cryotherapy on pain due to arterio- venous fistula puncture in haemodialysis patients, a-convenience sample of 30 patients (15 each in experimental and control groups) undergoing haemodialysis by using AVF, was assessed in a randomised control trial. Haemodialysis patients who met the inclusion criteria were randomly assigned to experimental and control groups using flip of coin method. Objective and subjective pain scoring was done on two consecutive days of HD treatment (with cryotherapyforthe experimental and without cryotherapy for the control group). The tools used were a questionnaire examining demographic and clinical characteristics, an adult non-verbalpain scale for assessing objective pain, and a numerical rating scale for subjective pain assessment. Descriptive statistics were used as deemed appropriate. Mann Whitney U test, Wilcoxon's signed rank test and Shapiro Wilk test were usedfor inferential statistics. We found that the objective and subjective pain scores were found to be significantly reduced within the experimental group with the application of cryotherapy (p=O.001). This study highlights the need for adopting alternative therapies such as cryotherapy for effective pain management in hospital settings.


Subject(s)
Arteriovenous Fistula/therapy , Cryotherapy/methods , Pain Management/methods , Pain/etiology , Punctures/adverse effects , Renal Dialysis/adverse effects , Adult , Aged , Female , Humans , India , Male , Middle Aged , Young Adult
18.
J Clin Diagn Res ; 8(1): 74-6, 2014 Jan.
Article in English | MEDLINE | ID: mdl-24596728

ABSTRACT

BACKGROUND AND OBJECTIVE: There is scarce information regarding TB associated with Human Immunodeficiency Virus (HIV) infection treated under routine program conditions in medical colleges of India. This study evaluates the clinical profile and outcome of TB-DOTS treatment by HIV status. METHODS: Total two hundred and eighty TB patients registered under Revised National Tuberculosis Control Program Revised National TB Control Program (RNTCP) during January 2011 and December 2012 in a teaching hospital of South India were enrolled in the study. The demographic profile, treatment related data of these patients was obtained from RNTCP treatment card and the DOTS outcome of all enrolled cases depending on their HIV status was evaluated. Data was analysed using descriptive statistics and chi-square test. RESULTS: Among 280 TB patients enrolled 41 were HIV positive patients and 239 HIV negative. About 21% patients were retreatment patients. Over all, pulmonary TB was still the commonest form of TB among the registered patients. However, Extra Pulmonary (EPTB) was high among HIV positive TB patients. Treatment success among HIV positive TB patients was lower than HIV negative TB patients (61% vs. 79%). Further, 19.5% HIV positive and 8.3% HIV negative patients died. The proportions of defaulters and failures were similar in HIV positive and HIV negative patients. CONCLUSION: HIV co-infected TB patients responded poorly to DOTS as evidenced by lower success rates and higher mortality than HIV negative TB patients. A significant proportion of retreatment patients in our study is the matter of concern.

19.
Cell Rep ; 2(2): 386-96, 2012 Aug 30.
Article in English | MEDLINE | ID: mdl-22884371

ABSTRACT

Mosaic mutant analysis, the study of cellular defects in scattered mutant cells in a wild-type environment, is a powerful approach for identifying critical functions of genes and has been applied extensively to invertebrate model organisms. A highly versatile technique has been developed in mouse: MASTR (mosaic mutant analysis with spatial and temporal control of recombination), which utilizes the increasing number of floxed alleles and simultaneously combines conditional gene mutagenesis and cell marking for fate analysis. A targeted allele (R26(MASTR)) was engineered; the allele expresses a GFPcre fusion protein following FLP-mediated recombination, which serves the dual function of deleting floxed alleles and marking mutant cells with GFP. Within 24 hr of tamoxifen administration to R26(MASTR) mice carrying an inducible FlpoER transgene and a floxed allele, nearly all GFP-expressing cells have a mutant allele. The fate of single cells lacking FGF8 or SHH signaling in the developing hindbrain was analyzed using MASTR, and it was revealed that there is only a short time window when neural progenitors require FGFR1 for viability and that granule cell precursors differentiate rapidly when SMO is lost. MASTR is a powerful tool that provides cell-type-specific (spatial) and temporal marking of mosaic mutant cells and is broadly applicable to developmental, cancer, and adult stem cell studies.


Subject(s)
Alleles , Chromosome Disorders/genetics , Genetic Engineering/methods , Mutation , Recombination, Genetic , Animals , DNA Mutational Analysis/methods , Mice , Mice, Transgenic , Mosaicism
20.
Vitam Horm ; 88: 507-22, 2012.
Article in English | MEDLINE | ID: mdl-22391319

ABSTRACT

Dysregulated Hedgehog (Hh) signaling has been implicated in a growing number of human cancers. Although first identified as an important developmental signaling pathway crucial for cellular proliferation, differentiation, and migration during organogenesis in invertebrates, these fundamental processes have been co-opted in human cancers. Initial evidence for the Hh pathway in tumor biology comes from mutations of signaling pathway components in a hereditary cancer syndrome that typically results in basal-cell carcinoma and medulloblastoma. Subsequent analysis revealed that Hh pathway mutations are found in sporadic tumors as well as activated Hh signaling in several epithelial cancers independent of Hh pathway mutation status. Further, recent evidence has demonstrated paracrine Hh signaling within stromal cells of the tumor microenvironment with implications for drug delivery. Several Hh antagonists targeting the Hh receptor, Smoothened (SMO), have been developed and show efficacy in preclinical studies and early-stage clinical trials in humans. However, major issues with these small molecule compounds include rapid acquired resistance, potential developmental toxicities secondary to use in children, and limited efficacy in cancers driven by Hh signaling downstream of the SMO receptor.


Subject(s)
Antineoplastic Agents/therapeutic use , Hedgehog Proteins/antagonists & inhibitors , Neoplasms/drug therapy , Tumor Microenvironment/drug effects , Veratrum Alkaloids/therapeutic use , Animals , Antineoplastic Agents/pharmacology , Hedgehog Proteins/metabolism , Humans , Neoplasms/metabolism , Veratrum Alkaloids/pharmacology
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