WNT5B drives osteosarcoma stemness, chemoresistance and metastasis.

BACKGROUND: Treatment for osteosarcoma, a paediatric bone cancer with no therapeutic advances in over three decades, is limited by a lack of targeted therapies. Osteosarcoma frequently metastasises to the lungs, and only 20% of patients survive 5 years after the diagnosis of metastatic disease. We found that WNT5B is the most abundant WNT expressed in osteosarcoma tumours and its expression correlates with metastasis, histologic subtype and reduced survival. METHODS: Using tumor-spheroids to model cancer stem-like cells, we performed qPCR, immunoblotting, and immunofluorescence to monitor changes in gene and protein expression. Additionally, we measured sphere size, migration and forming efficiency to monitor phenotypic changes. Therefore, we characterised WNT5B's relevance to cancer stem-like cells, metastasis, and chemoresistance and evaluated its potential as a therapeutic target. RESULTS: In osteosarcoma cell lines and patient-derived spheres, WNT5B is enriched in stem cells and induces the expression of the stemness gene SOX2. WNT5B promotes sphere size, sphere-forming efficiency, and cell proliferation, migration, and chemoresistance to methotrexate (but not cisplatin or doxorubicin) in spheres formed from conventional cell lines and patient-derived xenografts. In vivo, WNT5B increased osteosarcoma lung and liver metastasis and inhibited the glycosaminoglycan hyaluronic acid via upregulation of hyaluronidase 1 (HYAL1), leading to changes in the tumour microenvironment. Further, we identified that WNT5B mRNA and protein correlate with the receptor ROR1 in primary tumours. Targeting WNT5B through inhibition of WNT/ROR1 signalling with an antibody to ROR1 reduced stemness properties, including chemoresistance, sphere size and SOX2 expression. CONCLUSIONS: Together, these data define WNT5B's role in driving osteosarcoma cancer stem cell expansion and methotrexate resistance and provide evidence that the WNT5B pathway is a promising candidate for treating osteosarcoma patients. KEY POINTS: WNT5B expression is high in osteosarcoma stem cells leading to increased stem cell proliferation and migration through SOX2. WNT5B expression in stem cells increases rates of osteosarcoma metastasis to the lungs and liver in vivo. The hyaluronic acid degradation enzyme HYAL1 is regulated by WNT5B in osteosarcoma contributing to metastasis. Inhibition of WNT5B with a ROR1 antibody decreases osteosarcoma stemness.

Eravacycline, the first four years: health outcomes and tolerability data for 19 hospitals in 5 U.S. regions from 2018 to 2022.

IMPORTANCE: The rise of multidrug-resistant (MDR) pathogens, especially MDR Gram-negatives, poses a significant challenge to clinicians and public health. These resilient bacteria have rendered many traditional antibiotics ineffective, underscoring the urgency for innovative therapeutic solutions. Eravacycline, a broad-spectrum fluorocycline tetracycline antibiotic approved by the FDA in 2018, emerges as a promising candidate, exhibiting potential against a diverse array of MDR bacteria, including Gram-negative, Gram-positive, anaerobic strains, and Mycobacterium. However, comprehensive data on its real-world application remain scarce. This retrospective cohort study, one of the largest of its kind, delves into the utilization of eravacycline across various infectious conditions in the USA during its initial 4 years post-FDA approval. Through assessing clinical, microbiological, and tolerability outcomes, the research offers pivotal insights into eravacycline's efficacy in addressing the pressing global challenge of MDR bacterial infections.

Time to defervescence evaluation for extended- vs. standard-infusion cefepime in patients with acute leukemia and febrile neutropenia.

BACKGROUND/OBJECTIVES: Febrile neutropenia (FN) occurs in up to 80% of patients with hematologic malignancies. Evidence suggests using extended infusions (EI) of beta-lactams can improve outcomes in some populations, but there is limited clinical literature comparing cefepime standard infusion (SI) versus EI for FN. The FDA-approved regimen for FN was used at a large community teaching hospital for patients with FN until a hospital-wide EI beta-lactam protocol was introduced that allowed for EI cefepime in FN at the physicians' discretion. We sought to compare outcomes between patients with FN who received SI and EI cefepime. METHODS: Patients with acute myeloid or lymphocytic leukemia who developed FN between April 2014 and January 2021 were included in this single-center, retrospective study. The primary outcome was to compare mean time to defervescence after the initiation of cefepime SI or EI regimens. SI regimens consisted of IV cefepime 2G q8h/0.5 h, and EI regimens as IV cefepime 1G q8h/4 h. Secondary outcomes included 30-day all-cause mortality, hospital length of stay (LOS), duration of cefepime, and need to escalate therapy. RESULTS: Overall, 193 patients were included. Baseline characteristics were similar between groups. Time to defervescence was significantly shorter with EI compared with the SI group (median 48 h [48-100.5] vs. 70 h [48-113], p = 0.005). Cefepime duration of therapy was significantly shorter in the EI compared with the SI group (median 6.0 days vs. 8.0 days, p = 0.002). There was no difference between other secondary outcomes including LOS, mortality, and antibiotic escalation. CONCLUSION: Despite reduced total daily dose of cefepime, EI cefepime administered as a 1G/0.5 h LD followed 2 h later by 1G q8h/4 h for FN acutely achieves more rapid defervescence than the FDA-approved SI regimen and ultimately attains comparable patient outcomes.

Clinical Outcomes of Eravacycline in Patients Treated Predominately for Carbapenem-Resistant Acinetobacter baumannii.

Forty-six patients were treated with eravacycline (ERV) for Acinetobacter baumannii infections, where 69.5% of isolates were carbapenem resistant (CRAB). Infections were primarily pulmonary (58.3%), and most patients received combination therapy (84.4%). The median (IQR) ERV duration was 6.9 days (5.1 to 11.1). Thirty-day mortality was 23.9% in the cohort and 21.9% in CRAB patients. One patient experienced an ERV-possible adverse event. IMPORTANCE Acinetobacter baumannii, particularly when carbapenem resistant (CRAB), is one of the most challenging pathogens in the health care setting. This is complicated by the fact that there is no consensus guideline regarding management of A. baumannii infections. However, the recent Infectious Diseases Society of America guidelines for treatment of resistant Gram-negative infections provided expert recommendations for CRAB management. The panel suggest using minocycline among tetracycline derivatives rather than eravacycline (ERV) until sufficient clinical data are available. Therefore, we present the largest multicenter real-world cohort in patients treated with ERV for A. baumannii, where the majority of isolates were CRAB (69.5%). Our analysis demonstrate that patients treated with ERV-based regimens achieved a 30-day mortality of 23.9% and had a low incidence of ERV-possible adverse events (2.1%). This study is important as it fills the gap in the literature regarding the use of a novel tetracycline (i.e., ERV) in the treatment of this challenging health care infection.