Background: It remains a matter of debate whether autophagy contributes to apoptosis. Results: Atg5 and p62 are required for an intracellular death-inducing signaling complex (iDISC) formation on autophagosomal membranes for caspase-8 self-processing. Conclusion: Autophagosome serves as a platform for the intracellular activation of caspase-8. Significance: Induction of iDISC formation may shift cytoprotective autophagy to apoptosis for more effective cancer therapies.

IntroductionData on race and ethnic disparities for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection are limited. We analysed sociodemographic factors associated with higher likelihood of SARS-CoV-2 infection and explore mediating pathways for race and ethnic disparities in the SARS-CoV-2 pandemic.MethodsThis is a cross-sectional analysis of the COVID-19 Surveillance and Outcomes Registry, which captures data for a large healthcare system, comprising one central tertiary care hospital, seven large community hospitals and an expansive ambulatory/emergency care network in the Greater Houston area. Nasopharyngeal samples for individuals inclusive of all ages, races, ethnicities and sex were tested for SARS-CoV-2. We analysed sociodemographic (age, sex, race, ethnicity, household income, residence population density) and comorbidity (Charlson Comorbidity Index, hypertension, diabetes, obesity) factors. Multivariable logistic regression models were fitted to provide adjusted OR (aOR) and 95% CI for likelihood of a positive SARS-CoV-2 test. Structural equation modelling (SEM) framework was used to explore three mediation pathways (low income, high population density, high comorbidity burden) for the association between non-Hispanic black (NHB) race, Hispanic ethnicity and SARS-CoV-2 infection.ResultsAmong 20 228 tested individuals, 1551 (7.7%) tested positive. The overall mean (SD) age was 51.1 (19.0) years, 62% were females, 22% were black and 18% were Hispanic. NHB and Hispanic ethnicity were associated with lower socioeconomic status and higher population density residence. In the fully adjusted model, NHB (vs non-Hispanic white; aOR, 2.23, CI 1.90 to 2.60) and Hispanic ethnicity (vs non-Hispanic; aOR, 1.95, CI 1.72 to 2.20) had a higher likelihood of infection. Older individuals and males were also at higher risk of infection. The SEM framework demonstrated a significant indirect effect of NHB and Hispanic ethnicity on SARS-CoV-2 infection mediated via a pathway including residence in densely populated zip code.ConclusionsThere is strong evidence of race and ethnic disparities in the SARS-CoV-2 pandemic that are potentially mediated through unique social determinants of health.

. Regulation of the renal thiazidesensitive Na-Cl cotransporter, blood pressure, and natriuresis in obese Zucker rats treated with rosiglitazone. Am J Physiol Renal Physiol 289: F442-F450, 2005. First published April 5, 2005; doi:10.1152/ajprenal.00335.2004.-Previously, we showed an increase in protein abundance of the renal thiazide-sensitive Na-Cl cotransporter (NCC) in young, prediabetic, obese Zucker rats relative to lean age mates (Bickel CA, Verbalis JF, Knepper MA, and Ecelbarger CA. Am J Physiol Renal Physiol 281: F639 -F648, 2001). To test whether this increase correlated with increased thiazide sensitivity (NCC activity) and blood pressure, and could be modified by insulinsensitizing agents, we treated lean and obese Zucker rats (9 wk old) with either a control diet or this diet supplemented with 3 mg/kg body wt rosiglitazone (RGZ), a peroxisomal proliferator-activated receptor subtype ␥ agonist and potent insulin-sensitizing agent, for 12 wk (n ϭ 9/group). The rise in blood pressure, measured continuously by radiotelemetry, was significantly blunted in the RGZ-treated obese rats. Similarly, blood glucose and urinary albumin were markedly decreased in these rats. RGZ-treated rats whether lean or obese excreted a NaCl load faster but excreted less sodium in response to hydrochlorothiazide, applied as a novel in vivo measure of NCC activity. Obese rats had increased renal protein abundance and urinary excretion of NCC; however, this was not significantly reduced by RGZ (densitometry in cortex homogenate Ϫ %lean control): 100 Ϯ 9, 93 Ϯ 4, 124 Ϯ 9, and 141 Ϯ 14 for lean control, lean RGZ, obese control, and obese RGZ, respectively. Subcellular localization, as evaluated by confocal microscopy and immunoblotting following differential centrifugation, of NCC was not different between rat groups. Overall, RGZ reduced blood pressure and thiazide sensitivity; however, the mechanism(s) did not seem to involve a decrease in NCC protein abundance or cellular location. Decreased NCC activity may have contributed to the maintenance of normotension in RGZ-treated obese rats. insulin resistance; type II diabetes; TSC THE OBESE ZUCKER RAT is a model of gross obesity with marked insulin resistance coupled to mild hypertension. Dysregulation of sodium balance and pressure-natriuresis as a result of insulin resistance likely are major contributors to the rise in blood pressure. Previously, we (4) showed increased renal abundances of three major sodium transport proteins in the kidney of the obese Zucker rat relative to lean age mates at both 2 and 4 mo of age, i.e., the thiazide-sensitive Na-Cl cotransporter (NCC or TSC), the ␤-subunit of the epithelial sodium channel (ENaC), and the ␣ 1 -subunit of Na-K-ATPase. These relative differences in protein abundance in the kidney seemed to be attenuated some in 6-mo-old rats, as the rats became fully diabetic and the kidneys hypertrophied (3). The mechanisms underlying these changes in abundance, i.e., transcriptional vs. changes in protein turnover rate, were not determined.T...

Ewing's Sarcoma family tumors (ESFT) are characterized by a translocation t(11:22) forming an aberrant transcription factor EWS-FLI1. Protein tyrosine phosphatase L1 (PTPL1) was identified as a gene upregulated by EWS-FLI1 in transfected cells by microarray. Our results show that PTPL1 is a transcriptional target of EWS-FLI1 both by chromatin immunoprecipitation and promoter activation studies. We demonstrate that PTPL1 is highly expressed in ESFT cells and patient tumors compared with normal tissues, with a trend towards higher expression in metastatic versus primary tumors. Reduction of PTPL1 protein in ESFT cells correlated with a significant reduction in both monolayer and soft-agar cell growth. In addition, these PTPL1-reduced cells were more sensitive to etoposide-induced apoptosis than the controls. We therefore report a novel transcriptional activation of a phosphatase involved in the oncogenesis of ESFT. Increasing interest in specific phosphatase inhibitors would allow PTPL1 to be evaluated as a therapeutic target in ESFT.

Ceramide is a sphingolipid metabolite that induces cancer cell death. When C6-ceramide is encapsulated in a nanoliposome bilayer formulation, cell death is selectively induced in tumor models. However, the mechanism underlying this selectivity is unknown. As most tumors exhibit a preferential switch to glycolysis, as described in the “Warburg effect”, we hypothesize that ceramide nanoliposomes selectively target this glycolytic pathway in cancer. We utilize chronic lymphocytic leukemia (CLL) as a cancer model, which has an increased dependency on glycolysis. In CLL cells, we demonstrate that C6-ceramide nanoliposomes, but not control nanoliposomes, induce caspase 3/7-independent necrotic cell death. Nanoliposomal ceramide inhibits both the RNA and protein expression of GAPDH, an enzyme in the glycolytic pathway, which is overexpressed in CLL. To confirm that ceramide targets GAPDH, we demonstrate that downregulation of GAPDH potentiates the decrease in ATP after ceramide treatment and exogenous pyruvate treatment as well as GAPDH overexpression partially rescues ceramide-induced necrosis. Finally, an in vivo murine model of CLL shows that nanoliposomal C6-ceramide treatment elicits tumor regression, concomitant with GAPDH downregulation. We conclude that selective inhibition of the glycolytic pathway in CLL cells with nanoliposomal C6-ceramide could potentially be an effective therapy for leukemia by targeting the Warburg effect.