22 research outputs found

    Modulation of RNA splicing enhances response to BCL2 inhibition in leukemia.

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    Therapy resistance is a major challenge in the treatment of cancer. Here, we performed CRISPR-Cas9 screens across a broad range of therapies used in acute myeloid leukemia to identify genomic determinants of drug response. Our screens uncover a selective dependency on RNA splicing factors whose loss preferentially enhances response to the BCL2 inhibitor venetoclax. Loss of the splicing factor RBM10 augments response to venetoclax in leukemia yet is completely dispensable for normal hematopoiesis. Combined RBM10 and BCL2 inhibition leads to mis-splicing and inactivation of the inhibitor of apoptosis XIAP and downregulation of BCL2A1, an anti-apoptotic protein implicated in venetoclax resistance. Inhibition of splicing kinase families CLKs (CDC-like kinases) and DYRKs (dual-specificity tyrosine-regulated kinases) leads to aberrant splicing of key splicing and apoptotic factors that synergize with venetoclax, and overcomes resistance to BCL2 inhibition. Our findings underscore the importance of splicing in modulating response to therapies and provide a strategy to improve venetoclax-based treatments

    Co-inhibition of SMAD and MAPK signaling enhances 124I uptake in BRAF-mutant thyroid cancers.

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    Constitutive MAPK activation silences genes required for iodide uptake and thyroid hormone biosynthesis in thyroid follicular cells. Accordingly, most BRAFV600E papillary thyroid cancers (PTC) are refractory to radioiodide (RAI) therapy. MAPK pathway inhibitors rescue thyroid-differentiated properties and RAI responsiveness in mice and patient subsets with BRAFV600E-mutant PTC. TGFB1 also impairs thyroid differentiation and has been proposed to mediate the effects of mutant BRAF. We generated a mouse model of BRAFV600E-PTC with thyroid-specific knockout of the Tgfbr1 gene to investigate the role of TGFB1 on thyroid-differentiated gene expression and RAI uptake in vivo. Despite appropriate loss of Tgfbr1, pSMAD levels remained high, indicating that ligands other than TGFB1 were engaging in this pathway. The activin ligand subunits Inhba and Inhbb were found to be overexpressed in BRAFV600E-mutant thyroid cancers. Treatment with follistatin, a potent inhibitor of activin, or vactosertib, which inhibits both TGFBR1 and the activin type I receptor ALK4, induced a profound inhibition of pSMAD in BRAFV600E-PTCs. Blocking SMAD signaling alone was insufficient to enhance iodide uptake in the setting of constitutive MAPK activation. However, combination treatment with either follistatin or vactosertib and the MEK inhibitor CKI increased 124I uptake compared to CKI alone. In summary, activin family ligands converge to induce pSMAD in Braf-mutant PTCs. Dedifferentiation of BRAFV600E-PTCs cannot be ascribed primarily to activation of SMAD. However, targeting TGFβ/activin-induced pSMAD augmented MAPK inhibitor effects on iodine incorporation into BRAF tumor cells, indicating that these two pathways exert interdependent effects on the differentiation state of thyroid cancer cells

    Global, regional, and national burden of disorders affecting the nervous system, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021

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    BackgroundDisorders affecting the nervous system are diverse and include neurodevelopmental disorders, late-life neurodegeneration, and newly emergent conditions, such as cognitive impairment following COVID-19. Previous publications from the Global Burden of Disease, Injuries, and Risk Factor Study estimated the burden of 15 neurological conditions in 2015 and 2016, but these analyses did not include neurodevelopmental disorders, as defined by the International Classification of Diseases (ICD)-11, or a subset of cases of congenital, neonatal, and infectious conditions that cause neurological damage. Here, we estimate nervous system health loss caused by 37 unique conditions and their associated risk factors globally, regionally, and nationally from 1990 to 2021.MethodsWe estimated mortality, prevalence, years lived with disability (YLDs), years of life lost (YLLs), and disability-adjusted life-years (DALYs), with corresponding 95% uncertainty intervals (UIs), by age and sex in 204 countries and territories, from 1990 to 2021. We included morbidity and deaths due to neurological conditions, for which health loss is directly due to damage to the CNS or peripheral nervous system. We also isolated neurological health loss from conditions for which nervous system morbidity is a consequence, but not the primary feature, including a subset of congenital conditions (ie, chromosomal anomalies and congenital birth defects), neonatal conditions (ie, jaundice, preterm birth, and sepsis), infectious diseases (ie, COVID-19, cystic echinococcosis, malaria, syphilis, and Zika virus disease), and diabetic neuropathy. By conducting a sequela-level analysis of the health outcomes for these conditions, only cases where nervous system damage occurred were included, and YLDs were recalculated to isolate the non-fatal burden directly attributable to nervous system health loss. A comorbidity correction was used to calculate total prevalence of all conditions that affect the nervous system combined.FindingsGlobally, the 37 conditions affecting the nervous system were collectively ranked as the leading group cause of DALYs in 2021 (443 million, 95% UI 378–521), affecting 3·40 billion (3·20–3·62) individuals (43·1%, 40·5–45·9 of the global population); global DALY counts attributed to these conditions increased by 18·2% (8·7–26·7) between 1990 and 2021. Age-standardised rates of deaths per 100 000 people attributed to these conditions decreased from 1990 to 2021 by 33·6% (27·6–38·8), and age-standardised rates of DALYs attributed to these conditions decreased by 27·0% (21·5–32·4). Age-standardised prevalence was almost stable, with a change of 1·5% (0·7–2·4). The ten conditions with the highest age-standardised DALYs in 2021 were stroke, neonatal encephalopathy, migraine, Alzheimer's disease and other dementias, diabetic neuropathy, meningitis, epilepsy, neurological complications due to preterm birth, autism spectrum disorder, and nervous system cancer.InterpretationAs the leading cause of overall disease burden in the world, with increasing global DALY counts, effective prevention, treatment, and rehabilitation strategies for disorders affecting the nervous system are needed

    HSP90 inhibition mediated AXL receptor tyrosine kinase downregulation-molecular mechanism and therapeutic implication.

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    The Tyrosine kinase receptor AXL belongs to the TAM (Tyro3, AXL and Mer) family, whose members are characterized by a highly conserved kinase domain and adhesion molecule-like domains in the extracellular region. There are several reports showing AXL overexpression in cancer and its transforming potential, depicting its ability to drive tumor formation, progression and resistance to different anti-cancer agents; hence, AXL receptor is a clinically validated cancer target. Heat shock protein 90 (HSP90) is a critical player in regulating the maturation, stability, and activity of its client proteins. HSP90 inhibition causes depletion of multiple oncogenic client proteins, leading to blockade of many key cancer causing pathways. HSP90 inhibitors that derived from geldanamycin, such as 17-AAG, have emerged as promising therapeutic agents for cancer treatment and few of them have entered clinical trials. In this study we show that AXL is a novel client of HSP90, as the two structurally unrelated HSP90 inhibitors Radicicol or 17-AAG, induced a time- and dose-dependent downregulation of endogenous or ectopically expressed AXL protein. Using biotin and 35S-methionine labelling of the biogenesis/trafficking receptor upon 17-AAG treatment we showed that 17-AAG induced depletion of AXL on the plasma membrane, by mediating degradation of fully glycosylated AXL receptor from internal organelles and therefore restricting its transport to the cell surface. We demonstrated that 17-AAG induced AXL polyubiquitination and subsequent degradation via proteasome. HSP90 functions in the context of a multi-protein chaperone complex. By co-immunoprecipitation experiments, interactions between AXL and the components of chaperone complex like HSP90 itself, HSP70, and Ubiquitin E3 ligase CHIP (Carboxy terminus of Hsc70 Interacting Protein) were shown to be modulated by 17-AAG treatment. By contrast to wt CHIP, the functionally inactive CHIP mutant, CHIP K30A failed to accumulate AXL polyubiquitinated species even in the presence of 17-AAG, suggesting the involvement of endogenous CHIP in 17-AAG induced AXL polyubiquitination. We could also show that, it is the intracellular domain (ICD) of AXL containing the TK domain that is crucial to acquire 17-AAG sensitivity, as the AXL ICD-deleted mutant is insensitive to 17-AAG mediated degradation. However, AXL kinase activity is not required for 17-AAG mediated AXL loss, since inhibition of kinase activity by Bosutinib did not affect AXL sensitivity to 17-AAG. Similarly, AXL kinase dead mutant was as sensitive as the wt receptor to 17-AAG induced degradation. Finally, we also demonstrated that 17-AAG induced AXL downregulation could interfere with AXL mediated biological activity, measured as activation of transcription from the AP1 promoter, suggesting a possible therapeutic approach to counteract AXL driven oncogenic activity or drug resistance. Our data convincingly clarify the molecular basis of AXL downregulation by HSP90 inhibitor 17-AAG and suggest that HSP90 inhibition in anti-cancer therapy can exert its effect through inhibition of multiple kinases, including AXL itself

    A study on ECG signal characterization and practical implementation of some ECG characterization techniques

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    The role of ECG is pivotal in medical field for the analysis of cardiac physiology and abnormalities. The interpretation of ECG signal is performed by signal processing algorithms for diagnosis of cardiac diseases. This work analyses filtering approaches, component extraction, classification and compression algorithms for the ECG signal. The portable ECG systems are also analysed; results and discussion comprises of IIR notch filter for the removal of power line interference, hybrid wavelet filter for removal of baseline wander, FFT algorithm for R peak detection and hybrid filtering approach for the detection of P, QRS and T components. The outcome of this research work is an aid for researchers developing novel algorithms in ECG filtering, segmentation and classification. The algorithms are developed in Matlab 2015b and tested on fantasia database data sets
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