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Background: Endothelial cells regulate their cell cycle as blood vessels remodel and transition to quiescence downstream of blood flow-induced mechanotransduction. Laminar blood flow leads to quiescence, but how flow-mediated quiescence is established and maintained is poorly understood., Methods: Primary human endothelial cells were exposed to laminar flow regimens and gene expression manipulations, and quiescence depth was analyzed via time-to-cell cycle reentry after flow cessation. Mouse and zebrafish endothelial expression patterns were examined via scRNA-seq (single-cell RNA sequencing) analysis, and mutant or morphant fish lacking p27 were analyzed for endothelial cell cycle regulation and in vivo cellular behaviors., Results: Arterial flow-exposed endothelial cells had a distinct transcriptome, and they first entered a deep quiescence, then transitioned to shallow quiescence under homeostatic maintenance conditions. In contrast, venous flow-exposed endothelial cells entered deep quiescence early that did not change with homeostasis. The cell cycle inhibitor p27 ( CDKN1B ) was required to establish endothelial flow-mediated quiescence, and expression levels positively correlated with quiescence depth. p27 loss in vivo led to endothelial cell cycle upregulation and ectopic sprouting, consistent with loss of quiescence. HES1 and ID3, transcriptional repressors of p27 upregulated by arterial flow, were required for quiescence depth changes and the reduced p27 levels associated with shallow quiescence., Conclusions: Endothelial cell flow-mediated quiescence has unique properties and temporal regulation of quiescence depth that depends on the flow stimulus. These findings are consistent with a model whereby flow-mediated endothelial cell quiescence depth is temporally regulated downstream of p27 transcriptional regulation by HES1 and ID3. The findings are important in understanding endothelial cell quiescence misregulation that leads to vascular dysfunction and disease., Competing Interests: Disclosures None.

BMP signaling is crucial to blood vessel formation and function, but how pathway components regulate vascular development is not well-understood. Here, we find that inhibitory SMAD6 functions in endothelial cells to negatively regulate ALK1-mediated responses, and it is required to prevent vessel dysmorphogenesis and hemorrhage in the embryonic liver vasculature. Reduced Alk1 gene dosage rescued embryonic hepatic hemorrhage and microvascular capillarization induced by Smad6 deletion in endothelial cells in vivo. At the cellular level, co-depletion of Smad6 and Alk1 rescued the destabilized junctions and impaired barrier function of endothelial cells depleted for SMAD6 alone. Mechanistically, blockade of actomyosin contractility or increased PI3K signaling rescued endothelial junction defects induced by SMAD6 loss. Thus, SMAD6 normally modulates ALK1 function in endothelial cells to regulate PI3K signaling and contractility, and SMAD6 loss increases signaling through ALK1 that disrupts endothelial cell junctions. ALK1 loss-of-function also disrupts vascular development and function, indicating that balanced ALK1 signaling is crucial for proper vascular development and identifying ALK1 as a 'Goldilocks' pathway in vascular biology that requires a certain signaling amplitude, regulated by SMAD6, to function properly., Competing Interests: Competing interests The authors declare no competing or financial interests., (© 2023. Published by The Company of Biologists Ltd.)

Endothelial cells line all blood vessels, where they coordinate blood vessel formation and the blood-tissue barrier via regulation of cell-cell junctions. The nucleus also regulates endothelial cell behaviors, but it is unclear how the nucleus contributes to endothelial cell activities at the cell periphery. Here, we show that the nuclear-localized li nker of the n ucleoskeleton and c ytoskeleton (LINC) complex protein SUN1 regulates vascular sprouting and endothelial cell-cell junction morphology and function. Loss of murine endothelial Sun1 impaired blood vessel formation and destabilized junctions, angiogenic sprouts formed but retracted in SUN1-depleted sprouts, and zebrafish vessels lacking Sun1b had aberrant junctions and defective cell-cell connections. At the cellular level, SUN1 stabilized endothelial cell-cell junctions, promoted junction function, and regulated contractility. Mechanistically, SUN1 depletion altered cell behaviors via the cytoskeleton without changing transcriptional profiles. Reduced peripheral microtubule density, fewer junction contacts, and increased catastrophes accompanied SUN1 loss, and microtubule depolymerization phenocopied effects on junctions. Depletion of GEF-H1, a microtubule-regulated Rho activator, or the LINC complex protein nesprin-1 rescued defective junctions of SUN1-depleted endothelial cells. Thus, endothelial SUN1 regulates peripheral cell-cell junctions from the nucleus via LINC complex-based microtubule interactions that affect peripheral microtubule dynamics and Rho-regulated contractility, and this long-range regulation is important for proper blood vessel sprouting and junction integrity., Competing Interests: DB, PB, MK, ZL, EM, AG, AM, AB, NT, MO, SR, KK, BJ, CS, SR, CG No competing interests declared, VB Reviewing editor, eLife, (© 2023, Buglak et al.)

Background: Cetuximab is an anti-epidermal growth factor receptor mouse-human chimeric monoclonal antibody used to treat advanced colorectal cancers. Initial data suggest that severe infusion reactions occurred in 4.5%, many on first exposure. The majority of those with anaphylactic reactions possess predeveloped IgE antibodies to galactose-alpha-1,3-galactose. It is thought that the vector for preexposure to alpha-gal is antigen inoculation via tick bites. This retrospective study reviews the experience of two community cancer centers in high tick exposure areas in Sydney with cetuximab anaphylaxis and proposes a protocol to avoid this., Method: Severe cetuximab infusion reactions occurring in the Northern Cancer Institute Frenchs Forest and St Leonards clinics, Sydney, from May 2014 to February 2019 were recorded. Area of residence was then compared to areas of known high tick prevalence., Results: A total of 87 patients received cetuximab in this period. Six patients (6.9%) experienced at least a grade 3 reaction, three females, age range 41-72 years (median 57.5 years). All were receiving cetuximab for metastatic colorectal cancer and their anaphylaxis occurred with the first infusion in all cases., Conclusion: These cases support the existing theory of increased rates of cetuximab anaphylaxis in areas of high tick prevalence. Given this, we recommend the following protocol for patients being considered for cetuximab therapy: known mammalian meat allergy as an absolute contraindication; all patients receiving cetuximab should have RAST (ImmunoCAP ® ) testing for alpha-gal specific-IgE-specific antibodies before first infusion and those who test positive to be considered alternate therapy., (© 2020 John Wiley & Sons Australia, Ltd.)

Purpose: In Australia, the number of cancer cases has doubled since 1991 and is the second most common cause of death as reported by Chen, H., et al. (Supportive Care in Cancer, 2018. 27: p. 451-460). Chemotherapy, a common treatment, is known to cause distressing symptoms that often lead to a person presenting to an emergency department (ED). The aim of this study was to investigate whether a nurse practitioner (NP)-led model of care could improve cancer service integration and reduce hospital presentations., Methods: This was an evaluation study for a new model of care that included (i) telephone helpline; (ii) urgent assessment clinic; and (iii) rapid day treatment consultation service., Results: The utilisation rate was 337 telephone calls involving 157 patients in the 7-month pilot. The most common reason for calling the helpline was for symptom management (n = 173, 51%), followed by education regarding treatment (n = 61, 18%). As a result, 49% (n = 165) of callers were given advice, information, or education; 22% (n = 74) were referred on to other healthcare providers; and 11% (38) were admitted to hospital. Of the 38 admitted patients, 9 were admitted directly from the urgent NP-led clinic bypassing the ED., Conclusions: The implementation of the NP-led model of care has reduced ED presentations, optimised symptom management, and streamlined patient telephone enquiries using validated clinical assessment tools (Jones 2018) within cancer services. The telephone helpline was available for the broader local health district community and was actively utilised. Patient surveys were overwhelmingly positive. The model of care has improved symptom management for patients and reduced ED workload and presentation rates.

The endothelial to haematopoietic transition (EHT) is the process whereby haemogenic endothelium differentiates into haematopoietic stem and progenitor cells (HSPCs). The intermediary steps of this process are unclear, in particular the identity of endothelial cells that give rise to HSPCs is unknown. Using single-cell transcriptome analysis and antibody screening, we identify CD44 as a marker of EHT enabling us to isolate robustly the different stages of EHT in the aorta-gonad-mesonephros (AGM) region. This allows us to provide a detailed phenotypical and transcriptional profile of CD44-positive arterial endothelial cells from which HSPCs emerge. They are characterized with high expression of genes related to Notch signalling, TGFbeta/BMP antagonists, a downregulation of genes related to glycolysis and the TCA cycle, and a lower rate of cell cycle. Moreover, we demonstrate that by inhibiting the interaction between CD44 and its ligand hyaluronan, we can block EHT, identifying an additional regulator of HSPC development.

Background: Patients with advanced malignancies have historically been considered poor candidates for admission to the intensive care unit (ICU); however, prognosis is continually improving, and requirements for ICU access are increasing., Aim: To understand the characteristics and outcomes of oncology unit patients admitted to an Australian ICU and identify potential prognostic factors., Methods: A single-centre, retrospective, cohort study conducted at a tertiary public hospital with a quaternary ICU in Sydney, Australia. All patients admitted under the medical oncology team requiring ICU admission between June 2014 and June 2016 were evaluated. Clinical outcomes were determined including mortality, ICU requirements (ventilation, dialysis, vasopressors, infection) and prognostic scores (Acute Physiologic and Chronic Health Evaluation (APACHE) II and Sequential Organ Failure Assessment (SOFA) score)., Results: There were 96 patients with mean age 61 years, 58% were male and 76% had metastatic disease. Most were receiving palliative treatment (89%), with recent chemotherapy (43%), immunotherapy (10%) and other therapies (5%). Of the 10 patients with recent immunotherapy, three (all with melanoma) required ICU admission due to immunotoxicity; 13% were admitted due to an oncological emergency. Mean APACHE II score was 17 (standard deviation (SD) 5.33), mean SOFA score was 3.99 (SD 2.70), ICU mortality was 5% and hospital mortality was 22%. Using multivariate logistic regression analysis, cancer stage, infection during ICU admission, intracranial mass effect on ICU admission and SOFA score were associated with 30-day mortality., Conclusion: Our patient population had good short-term survival outcomes despite most receiving palliative treatment. Cancer patients can achieve positive outcomes after ICU admission, and appropriate selection of patients is crucial., (© 2018 Royal Australasian College of Physicians.)

Metastatic uveal melanoma is a rare malignancy with a poor prognosis. To date, systemic therapy has been ineffective; however, there are few data on the benefits of anti-CTLA4 or anti-PD-1 antibodies in sequence with liver-directed therapy. A retrospective cohort analysis was carried out on 37 consecutive patients managed in a tertiary referral centre examining the safety and efficacy of treatment; patterns of care; and impact on survival. The sequential treatment with transarterial chemotherapy (TAC), systemic immunotherapy (IT) and systemic chemotherapy was reviewed. In all, 18 patients in the series received sequential therapy. The median overall survival (OS) was 17 months (n=37), which compared favourably with previously reported series. Patients treated with TAC first or second line had an overall progression-free survival (PFS) of 9 months (n=29) and IT PFS 7 months (n=26). The overall response rate (ORR) for TAC first line was 26% and the disease control rate (DCR) was 65% (n=23). ORR for IT first line was 7%, DCR 77% (n=14). Second-line (cross-over) IT ORR was 16%, DCR 58% (n=12). For second-line (cross-over) TAC, ORR was 50% and DCR was 66% (n=6). Toxicity was manageable. There were no cases of autoimmune hepatitis. In this retrospective small series analysis in uveal melanoma, liver-directed therapy and IT in sequence have shown to be active and reasonably well tolerated. Further prospective clinical trials should clarify the role of these treatments and their potential survival benefit.

Introduction: There is increasing evidence of cancer patients presenting to emergency departments (ED). The study aim was to analyse the characteristics of adult cancer patients presenting to one ED. Understanding cancer patient presentations could assist in the development of new models of care., Methods: A 12 month retrospective audit was conducted of a random sample of cancer patients. Demographics and characteristic variables were analysed using descriptive, comparative and correlational statistics., Results: The presentation rate for adult cancer patients was 1110 (2.4%) with 290 sampled. The common symptoms were fever (n = 54: 18.6%), abdominal pain (n = 34: 11.7%), and shortness of breath (n = 32: 11%). The majority of patients were allocated a Triage Category 2 (n = 94: 32.4%) or Triage Category 3 (n = 131: 45.2%). The majority of patients presented between 2 and 15 times. For patients administered antibiotics the average time was 119.8 minutes (SD ± 85.5). The average ED length of stay was mean 8.08 hours with 271 patients (93.4%) admitted to the hospital. Of the 290 patients, 105 (36.2%) had died within 12 months of ED presentation., Conclusion: The study has shown that while cancer patients are only a small percentage of ED presentations the vast majority are allocated high triage codes, have high admission rates and high mortality rates., (Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.)

RNA interference technology allows the systematic genetic analysis of the molecular alterations in cancer cells and how these alterations affect response to therapies. Here we used small interfering RNA (siRNA) screens to identify genes that enhance the cytotoxicity (enhancers) of established anticancer chemotherapeutics. Hits identified in drug enhancer screens of cisplatin, gemcitabine, and paclitaxel were largely unique to the drug being tested and could be linked to the drug's mechanism of action. Hits identified by screening of a genome-scale siRNA library for cisplatin enhancers in TP53-deficient HeLa cells were significantly enriched for genes with annotated functions in DNA damage repair as well as poorly characterized genes likely having novel functions in this process. We followed up on a subset of the hits from the cisplatin enhancer screen and validated a number of enhancers whose products interact with BRCA1 and/or BRCA2. TP53(+/-) matched-pair cell lines were used to determine if knockdown of BRCA1, BRCA2, or validated hits that associate with BRCA1 and BRCA2 selectively enhances cisplatin cytotoxicity in TP53-deficient cells. Silencing of BRCA1, BRCA2, or BRCA1/2-associated genes enhanced cisplatin cytotoxicity approximately 4- to 7-fold more in TP53-deficient cells than in matched TP53 wild-type cells. Thus, tumor cells having disruptions in BRCA1/2 network genes and TP53 together are more sensitive to cisplatin than cells with either disruption alone.

Four experiments are reported in which it is shown that elderly adults are more prone than young adults to olfactory adaptation and are slower to recover threshold sensitivity. The first three experiments differed in detail, but had in common an initial threshold determination for 1-butanol, a 30 s exposure to a concentration twenty-seven times threshold, followed by repeated presentation of the initial threshold level at various intervals after adaptation. In three experiments accuracy of forced-choice discrimination was poor immediately after adaptation but tended to improve with time, and considerably faster in the young than in the elderly. In the fourth experiment, groups of twenty-three elderly and twenty-five young subjects threshold-matched for pyridine were compared. The subjects participated in three sessions in which pyridine was infused into a test chamber at either 2.5, 1.25, or 0 L min-1 (sham session). At 2.5 L min-1 both groups were able to track the buildup of odor intensity during infusion and its decline after infusion. In contrast, at 1.25 L min-1 only the young were able to track odor intensity, even though the concentration rose above initial threshold levels.