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Last Modified, February 28, 2021
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A novel dual Ca2+ sensor system regulates Ca2+-dependent neurotransmitter release

J Cell Biol

2021 Jihong Bai; Yu Wang

Ca2+-dependent neurotransmitter release requires synaptotagmins as Ca2+ sensors to trigger synaptic vesicle (SV) exocytosis via binding of their tandem C2 domains-C2A and C2B-to Ca2+. We have previously demonstrated that SNT-1, a mouse synaptotagmin-1 (Syt1) homologue, functions as the fast Ca2+ sensor in Caenorhabditis elegans. Here, we report a new Ca2+ sensor, SNT-3, which triggers delayed Ca2+-dependent neurotransmitter release. snt-1;snt-3 double mutants abolish evoked synaptic transmission, demonstrating that C. elegans NMJs use a dual Ca2+ sensor system. SNT-3 possesses canonical aspartate residues in both C2 domains, but lacks an N-terminal transmembrane (TM) domain. Biochemical evidence demonstrates that SNT-3 binds both Ca2+ and the plasma membrane. Functional analysis shows that SNT-3 is activated when SNT-1 function is impaired, triggering SV release that is loosely coupled to Ca2+ entry. Compared with SNT-1, which is tethered to SVs, SNT-3 is not associated with SV. Eliminating the SV tethering of SNT-1 by removing the TM domain or the whole N terminus rescues fast release kinetics, demonstrating that cytoplasmic SNT-1 is still functional and triggers fast neurotransmitter release, but also exhibits decreased evoked amplitude and release probability. These results suggest that the fast and slow properties of SV release are determined by the intrinsically different C2 domains in SNT-1 and SNT-3, rather than their N-termini-mediated membrane tethering. Our findings therefore reveal a novel dual Ca2+ sensor system in C. elegans and provide significant insights into Ca2+-regulated exocytosis.

The TOP vector: a new high-titer lentiviral construct for delivery of sgRNAs and transgenes to primary T cells

Mol Ther Methods Clin Dev

2021 Daryl Humes; Stephanie Rainwater; Julie Overbaugh

Efficient delivery of nucleic acids for the engineering of primary T cells is central to the study of the basic biology of these key immune effector cells and has clinical implications. To date, lentiviral vectors delivering guide RNAs for CRISPR-Cas9 editing are not optimal for use in primary cells. Herein, we describe the T cell optimized for packaging (TOP) vector for delivering guide RNAs and transgenes into primary T cells. The TOP vector produces high-titer virus compared to a routinely used guide RNA vector, resulting in a ~10-fold increase in transduction in T cells. Moreover, a TOP vector expressing a chimeric antigen receptor and a guide RNA targeting the T cell receptor showed an ~5- to 9-fold increased transduction efficiency with ~2- to 3-fold higher expression compared to the commonly used epHIV7 vector and was simultaneously able to mediate efficient knockout of the endogenous T cell receptor in >71% of transduced cells upon Cas9 electroporation. The increased packaging of the TOP vector genome into viral particles appears to contribute to its higher transduction efficiency. The TOP vector represents an optimal tool for tandem delivery of transgenes and guide RNAs to primary T cells for use in functional screens and immunotherapy applications.

CRISPR-Cas9 gene editing of hepatitis B virus in chronically infected humanized mice

Mol Ther Methods Clin Dev

2021 Michelle Loprieno; Nicholas Weber; Rossana Colon-Thillet; Larry Corey; Lindsay Klouser; Martine Aubert; Karsten Eichholz; Keith Jerome; Stephan Polyak; Harshana De Silva Feelixge; Zhenhua Li; Daniel Stone

Chronic hepatitis B virus (HBV) infection is a major public health problem. New treatment approaches are needed because current treatments do not target covalently closed circular DNA (cccDNA), the template for HBV replication, and rarely clear the virus. We harnessed adeno-associated virus (AAV) vectors and CRISPR-Staphylococcus aureus (Sa)Cas9 to edit the HBV genome in liver-humanized FRG mice chronically infected with HBV and receiving entecavir. Gene editing was detected in livers of five of eight HBV-specific AAV-SaCas9-treated mice, but not control mice, and mice with detectable HBV gene editing showed higher levels of SaCas9 delivery to HBV+ human hepatocytes than those without gene editing. HBV-specific AAV-SaCas9 therapy significantly improved survival of human hepatocytes, showed a trend toward decreasing total liver HBV DNA and cccDNA, and was well tolerated. This work provides evidence for the feasibility and safety of in vivo gene editing for chronic HBV infections, and it suggests that with further optimization, this approach may offer a plausible way to treat or even cure chronic HBV infections.

American Society of Hematology 2021 guidelines for management of venous thromboembolism: prevention and treatment in patients with cancer

Blood Adv

2021 Gary Lyman

BACKGROUND: Venous thromboembolism (VTE) is a common complication among patients with cancer. Patients with cancer and VTE are at a markedly increased risk for morbidity and mortality. OBJECTIVE: These evidence-based guidelines of the American Society of Hematology (ASH) are intended to support patients, clinicians, and other health care professionals in their decisions about the prevention and treatment of VTE in patients with cancer. METHODS: ASH formed a multidisciplinary guideline panel balanced to minimize potential bias from conflicts of interest. The guideline development process was supported by updated or new systematic evidence reviews. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach was used to assess evidence and make recommendations. RESULTS: Recommendations address mechanical and pharmacological prophylaxis in hospitalized medical patients with cancer, those undergoing a surgical procedure, and ambulatory patients receiving cancer chemotherapy. The recommendations also address the use of anticoagulation for the initial, short-term, and long-term treatment of VTE in patients with cancer. CONCLUSIONS: Strong recommendations include not using thromboprophylaxis in ambulatory patients receiving cancer chemotherapy at low risk of VTE and to use low-molecular-weight heparin (LMWH) for initial treatment of VTE in patients with cancer. Conditional recommendations include using thromboprophylaxis in hospitalized medical patients with cancer, LMWH or fondaparinux for surgical patients with cancer, LMWH or direct oral anticoagulants (DOAC) in ambulatory patients with cancer receiving systemic therapy at high risk of VTE and LMWH or DOAC for initial treatment of VTE, DOAC for the short-term treatment of VTE, and LMWH or DOAC for the long-term treatment of VTE in patients with cancer.

Alternative donor transplantation for myelodysplastic syndromes: haploidentical relative and matched unrelated donors

Blood Adv

2021 Filippo Milano

We compared outcomes in 603 patients with myelodysplastic syndrome (MDS) after HLA-haploidentical relative (n = 176) and HLA-matched unrelated (n = 427) donor hematopoietic cell transplantation (HCT) from 2012 to 2017, using the Center for International Blood and Marrow Transplant Research database. All transplantations used reduced-intensity conditioning regimens. Total-body irradiation plus cyclophosphamide and fludarabine was the predominant regimen for HLA-haploidentical relative donor HCT, and graft-versus-host disease (GVHD) prophylaxis was uniformly posttransplantation cyclophosphamide, calcineurin inhibitor, and mycophenolate. Fludarabine with busulfan or melphalan was the predominant regimen for HLA-matched unrelated donor HCT, and GVHD prophylaxis was calcineurin inhibitor with mycophenolate or methotrexate. Results of multivariate analysis revealed higher relapse (hazard ratio [HR], 1.56; P = .0055; 2-year relapse rate, 48% vs 33%) and lower disease-free survival (DFS) rates after HLA-haploidentical relative donor HCT (HR, 1.29; P = .042; 2-year DFS, 29% vs 36%). However, overall survival (OS) rates did not differ between donor type (HR, 0.94; P = .65; 2-year OS, 46% for HLA-haploidentical and 44% for HLA-matched unrelated donor HCT) because of mortality associated with chronic GVHD. Acute grade 2 to 4 GVHD (HR, 0.44; P < .0001) and chronic GVHD (HR, 0.36; P < .0001) were lower after HLA-haploidentical relative donor HCT. By 2 years, probability of death resulting from chronic GVHD was lower after HLA-haploidentical relative compared with HLA-matched unrelated donor HCT (6% vs 21%), negating any potential survival advantage from better relapse control. Both donor types extend access to transplantation for patients with MDS; strategies for better relapse control are desirable for HLA-haploidentical relative donor HCT, and effective GVHD prophylaxis regimens are needed for unrelated donor HCT.

New Directions in Research on Heterogeneity of Treatment Effects for Major Depression

JAMA Psychiatry

2021 Alexander Luedtke

N/A

Cost-effectiveness of obinutuzumab versus rituximab biosimilars for previously untreated follicular lymphoma

J Manag Care Spec Pharm

2021 David Veenstra

BACKGROUND: In the randomized phase 3 GALLIUM trial, first-line treatment with obinutuzumab (GA101; G) plus chemotherapy (G + chemo) resulted in superior progression-free survival (PFS) compared with rituximab plus chemotherapy (R + chemo) for patients with follicular lymphoma (FL). G + chemo was found to be cost-effective when compared with R + chemo (incremental cost-effectiveness ratio [ICER] of approximately $2,300 per quality-adjusted life-year [QALY] gained). Two rituximab biosimilars, rituximab-abbs (Ra) and rituximab-pvvr (Rp), have been approved by the FDA for use in this setting. However, the cost-effectiveness of G + chemo versus Ra + chemo and Rp + chemo has not yet been estimated. OBJECTIVE: To evaluate the cost-effectiveness of G + chemo versus Ra + chemo and Rp + chemo in the first-line treatment of FL. METHODS: We adapted an existing Markov model that compared G + chemo with R + chemo, using investigator-assessed PFS and postprogression survival data from the GALLIUM trial to model overall survival. All patients in the study received induction chemoimmunotherapy with either G + chemo or R + chemo, with responders then receiving obinutuzumab or rituximab maintenance therapy for 2 years or until disease progression. We assumed that the efficacy and safety of the rituximab biosimilars plus chemotherapy were the same as the R + chemo arm of the GALLIUM study. Drug utilization and treatment duration were also derived from GALLIUM. Health care costs were based on Medicare reimbursements, and drug costs were average sale prices for intravenous therapies or wholesale acquisition costs for oral therapies used after progression. Utility estimates were based on the GALLIUM trial data and published literature. Sensitivity analyses were conducted to assess the key drivers of the model and uncertainty in the results. Results: Treatment with G + chemo led to an increase of 0.93 QALYs relative to rituximab biosimilars plus chemotherapy (95% credible range [CR] = 0.36-1.46). The total cost of G + chemo was $191,317, whereas the total costs of Ra + chemo and Rp + chemo were $164,340 (Δ14.1%) and $169,755 (Δ11.3%), respectively, with G + chemo resulting in incremental costs of $26,978 (95% CR = $19,781-$33,119) and $21,562 (95% CR = $14,473-$28,389), respectively. The incremental total drug and administration costs were $32,678 (Δ25.4%) and $27,263 (Δ21.2%) for G + chemo versus Ra + chemo and G + chemo versus Rp + chemo, respectively. There were cost savings of $7,050 (Δ-12.4%) related to disease progression for G + chemo ($56,727) compared with Ra + chemo and Rp + chemo ($63,777). ICERs were $28,879 and $23,082 per QALY gained for G + chemo versus Ra + chemo and Rp + chemo, respectively. In probabilistic sensitivity analyses, G + chemo was cost-effective at the $50,000 and $100,000 per QALY thresholds versus both Ra + chemo (88% and 98% probabilities of cost-effectiveness, respectively) and Rp + chemo (93% and 98%, respectively). CONCLUSIONS: G + chemo is projected to be cost-effective versus rituximab biosimilars plus chemotherapy in the United States as first-line treatment for FL, driven by increased QALYs for G + chemo and cost savings from delayed disease progression. DISCLOSURES: This study was funded by Genentech, a member of the Roche Group. The study sponsor was involved in study design, data interpretation, and writing of the report. All authors approved the decision to submit the report for publication. Spencer and Guzauskas report fees from Genentech during the conduct of the study. Felizzi was employed by F. Hoffmann-La Roche at the time this study was conducted; Launonen is an employees of F. Hoffmann-La Roche. Felizzi and Launonen previously had share ownership in Novartis. Dawson and Masaquel are employees of Genentech, and they have stock options in F. Hoffmann-La Roche. Veenstra reports fees from Genentech, during the conduct of this study and outside of the submitted work. This work was presented, in part, at the AACR Virtual Meeting Advances in Malignant Lymphoma meeting (virtual; August 17-19, 2020) and the SOHO annual meeting (virtual; September 9-12, 2020).

MAPK4 promotes prostate cancer by concerted activation of androgen receptor and AKT

J Clin Invest

2021 Peter Nelson; Ilsa Coleman

Prostate cancer (PCa) is the second leading cause of cancer death in American men. Androgen receptor (AR) signaling is essential for PCa cell growth/survival and remains a key therapeutic target for lethal castration-resistant PCa (CRPC). GATA2 is a pioneer transcription factor crucial for inducing AR expression/activation. We recently reported that MAPK4, an atypical MAPK, promotes tumor progression via noncanonical activation of AKT. Here, we demonstrated that MAPK4 activated AR by enhancing GATA2 transcriptional expression and stabilizing GATA2 protein through repression of GATA2 ubiquitination/degradation. MAPK4 expression correlated with AR activation in human CRPC. Concerted activation of both GATA2/AR and AKT by MAPK4 promoted PCa cell proliferation, anchorage-independent growth, xenograft growth, and castration resistance. Conversely, knockdown of MAPK4 decreased activation of both AR and AKT and inhibited PCa cell and xenograft growth, including castration-resistant growth. Both GATA2/AR and AKT activation were necessary for MAPK4 tumor-promoting activity. Interestingly, combined overexpression of GATA2 plus a constitutively activated AKT was sufficient to drive PCa growth and castration resistance, shedding light on an alternative, MAPK4-independent tumor-promoting pathway in human PCa. We concluded that MAPK4 promotes PCa growth and castration resistance by cooperating parallel pathways of activating GATA2/AR and AKT and that MAPK4 is a novel therapeutic target in PCa, especially CRPC.

Targeting the membrane-proximal C2-set domain of CD33 for improved CD33-directed immunotherapy

Leukemia

2021 Colin Correnti; Salvatore Fiorenza; Cameron Turtle; Roland Walter; George Laszlo; Eliotte Garling; Margaret Lunn; Olivia Bates; Colin Godwin; Olivier Humbert; Hans-Peter Kiem; Benjamin Hoffstrom; Tinhdoan Phi

There is increasing interest in targeting CD33 in malignant and non-malignant disorders. In acute myeloid leukemia, longer survival with the CD33 antibody-drug conjugate gemtuzumab ozogamicin (GO) validates this strategy. Still, GO benefits only some patients, prompting efforts to develop more potent CD33-directed therapeutics. As one limitation, CD33 antibodies typically recognize the membrane-distal V-set domain. Using various artificial CD33 proteins, in which this domain was differentially positioned within the extracellular portion of the molecule, we tested whether targeting membrane-proximal epitopes enhances the effector functions of CD33 antibody-based therapeutics. Consistent with this idea, a CD33V-set/CD3 bispecific antibody (BsAb) and CD33V-set-directed chimeric antigen receptor (CAR)-modified T cells elicited substantially greater cytotoxicity against cells expressing a CD33 variant lacking the entire C2-set domain than cells expressing full-length CD33, whereas cytotoxic effects induced by GO were independent of the position of the V-set domain. We therefore raised murine and human antibodies against the C2-set domain of human CD33 and identified antibodies that bound CD33 regardless of the presence/absence of the V-set domain ("CD33PAN antibodies"). These antibodies internalized when bound to CD33 and, as CD33PAN/CD3 BsAb, had potent cytolytic effects against CD33+ cells. Together, our data provide the rationale for further development of CD33PAN antibody-based therapeutics.

Co-occurrence of immune-mediated conditions and endometriosis among adolescents and adult women

Am J Reprod Immunol

2021 Holly Harris

PROBLEM: Associations between immune dysfunction conditions (e.g. systemic lupus erythematous, rheumatoid arthritis) and endometriosis have been observed in adult women, but not assessed among a younger population. We investigated the association between immune-mediated conditions and endometriosis among young women. METHOD OF STUDY: This cross-sectional analysis in the Women's Health Study: From Adolescence to Adulthood included 551 participants with surgically-diagnosed endometriosis (median age=19) and 652 controls without endometriosis (median age=24). Participants completed an expanded Endometriosis Phenome and Biobanking Harmonization Project questionnaire. We used logistic regression to estimate odds ratios (OR) and 95% confidence intervals (CI) to investigate the associations between autoimmune/inflammatory, atopic, chronic pain/fatigue, and endocrine disorders with endometriosis, adjusting for confounders. RESULTS: Participants with any autoimmune and/or inflammatory condition had an increased odds of co-occurring endometriosis (OR:1.87; CI:0.92-3.80), as did participants with allergies (OR:1.76; CI:1.32-2.36), asthma (OR:1.35; CI:0.97-1.88), chronic fatigue syndrome and/or fibromyalgia (OR:5.81; CI:1.89-17.9), or previous mononucleosis (OR:1.75; CI:1.14-2.68). Odds of endometriosis were lower among participants with eczema (OR:0.68; CI:0.44-1.04). We observed a positive trend between the number of immune-mediated conditions and the odds of endometriosis (p-trend=0.0002). Endocrine disorders were not associated with endometriosis. CONCLUSIONS: Among this population of adolescents and adult women, endometriosis was more likely among participants with autoimmune and/or inflammatory diseases, allergies, asthma, previous mononucleosis infection, and chronic fatigue and/or fibromyalgia. We observed that an increasing number of immune-mediated conditions was positively associated with endometriosis risk. It is important for clinicians who care for adolescents and women with these conditions to consider endometriosis as a co-morbidity.

Last Modified, February 20, 2020