No abstract

Mutations in ARID1A rank amongst the most common molecular aberrations in human cancer.However, oncogenic consequences of ARID1A mutation in human cells remain poorly defined due to lack of forward genetic models. Here, CRISPR/Cas9-mediated ARID1A knockout in primary TP53 -/human gastric organoids induced morphologic dysplasia, tumorigenicity and mucinous differentiation. Genetic Wnt/-catenin activation rescued mucinous differentiation, but not hyperproliferation, suggesting alternative pathways of ARID1A KO-mediated transformation.ARID1A mutation induced transcriptional regulatory modules characteristic of MSI and EBV subtype human gastric cancer, including FOXM1-associated mitotic genes and BIRC5/survivin.Convergently, high-throughput compound screening indicated selective vulnerability of ARID1Adeficient organoids to inhibition of BIRC5/survivin, functionally implicating this pathway as an essential mediator of ARID1A KO-dependent early-stage gastric tumorigenesis. Overall, we define distinct pathways downstream of oncogenic ARID1A mutation, with non-essential Wntinhibited mucinous differentiation in parallel with essential transcriptional FOXM1/BIRC5stimulated proliferation, illustrating the general utility of organoid-based forward genetic cancer analysis in human cells.Research.

Synaptotagmin triggers rapid exocytosis of neurotransmitters from synaptic vesicles in response to Calcium (Ca 2þ ) ions. Here, we use a novel Nanodisc-based system, designed to be a soluble mimetic of the clamped synaptic vesicle-bilayer junction, combined with fluorescence resonance energy transfer (FRET) spectroscopy to monitor the structural relationships among SNAREs (soluble N-ethylmaleimide-sensitive factor attachment protein receptor), Synaptotagmin C2 domains, and the lipid bilayer in real time during the Ca 2þ -activation process. We report that Synaptotagmin remains rigidly fixed on the partially assembled SNARE complex with no detectable internal rearrangement of its C2 domains, even as it rapidly inserts into the bilayer. We hypothesize that this straightforward, one-step physical mechanism could explain how this Ca 2þsensor rapidly activates neurotransmitter release from the clamped state.

No abstract

To improve patient quality of life and reduce health care costs, many conditions formerly thought to require inpatient care are now treated in the outpatient setting. Outpatient induction chemotherapy for acute myeloid leukemia (AML) may confer similar benefits. This possibility prompted a pilot study to explore the safety and feasibility of intensive outpatient initial or salvage induction chemotherapy administration for adults with AML and high-risk myelodysplastic syndrome (MDS). Patients with no significant organ dysfunction and a treatment-related mortality (TRM) score corresponding to a day 28 mortality rate of <5% to 10% were eligible for study. Patients were treated as outpatients with daily evaluation by providers and only admitted to the hospital if mandated by complications. Twenty patients were consented, and 17 were treated. Eight patients received initial induction chemotherapy and 9 received salvage induction chemotherapy. Fourteen patients completed induction chemotherapy administration in the outpatient setting (82.4%; exact 95% confidence interval [CI], 55.8-95.3). Three patients were admitted during the course of chemotherapy administration, 2 for neutropenic fever and 1 for grade 3 mucositis. No patients died within 14 days of the initiation of induction chemotherapy (exact 95% CI, 0-22.9). Results of this pilot study suggest it is feasible to complete outpatient induction chemotherapy in select patients with AML and high-risk MDS. A team including nurses, social workers, medical providers, and pharmacists was key to the successful implementation of outpatient induction.