Validation of the HULL Score clinical prediction rule for unsuspected pulmonary embolism in ambulatory cancer patients.

Background: Clinical prediction rules (CPRs) developed to predict adverse outcomes of suspected pulmonary embolism (PE) and facilitate outpatient management have limitations in discriminating outcomes for ambulatory cancer patients with unsuspected PE (UPE). The HULL Score CPR uses a 5­point scoring system incorporating performance status and self-reported new or recently evolving symptoms at UPE diagnosis. It stratifies patients into low, intermediate and high risk for proximate mortality. This study aimed to validate the HULL Score CPR in ambulatory cancer patients with UPE. Patients and methods: 282 consecutive patients managed under the UPE-acute oncology service in Hull University Teaching Hospitals NHS Trust were included from January 2015 to March 2020. The primary end-point was all-cause mortality, and outcome measures were proximate mortality for the three risk categories of the HULL Score CPR. Results: 30-day, 90-day and 180-day mortality rates for the whole cohort were 3.4% (n=7), 21.1% (n=43) and 39.2% (n=80), respectively. The HULL Score CPR stratified patients into low-risk (n=100, 35.5%), intermediate-risk (n=95, 33.7%) and high-risk (n=81, 28.7%) categories. Correlation of the risk categories with 30-day mortality (area under the curve (AUC) 0.717, 95% CI 0.522-0.912), 90-day mortality (AUC 0.772, 95% CI 0.707-0.838), 180-day mortality (AUC 0.751, 95% CI 0.692-0.809) and overall survival (AUC 0.749, 95% CI 0.686-0.811) was consistent with the derivation cohort. Conclusion: This study validates the capacity of the HULL Score CPR to stratify proximate mortality risk in ambulatory cancer patients with UPE. The score uses immediately available clinical parameters and is easy to integrate into an acute outpatient oncology setting.

Duramycin-porphyrin conjugates for targeting of tumour cells using photodynamic therapy.

Duramycin, through binding with phosphatidylethanolamine (PE), has been shown to be a selective molecular probe for the targeting and imaging of cancer cells. Photodynamic therapy aims to bring about specific cytotoxic damage to tumours through delivery of a photosensitising agent and light irradiation. Conjugation to biological molecules that specifically target cancer has been shown to increase photosensitiser (PS) selectivity and decrease damage to surrounding normal tissue. The aim of this study was to target tumour cells with a PE-specific PS therefore duramycin was conjugated to a porphyrin based PS which was achieved via direct reaction with the ε-amino group on the lysine residue near duramycin's N-terminal. The compound was subsequently purified using RP-HPLC and confirmed using mass spectrometry. Binding of the conjugate to ovarian and pancreatic cancer cell lines was assessed by flow cytometry. Light irradiation with a light fluence of 7.5J/cm(2) was delivered to conjugate treated cancer cells and cell proliferation analysed by MTT assay. The conjugate detected PE on all 4 cancer cell lines in a concentration dependent manner and conjugate plus irradiation effectively reduced cell proliferation at concentrations ≥0.5µM, dependent on cancer cell line. Reduction in cell proliferation by the irradiated conjugate was enhanced over unconjugated duramycin in A2780, AsPC-1 and SK-OV-3 (p<0.05). In this study we have shown that a duramycin-porphyrin conjugate retained good binding affinity for its target and, following irradiation, reduced cell proliferation of pancreatic and ovarian cancer cell lines.

Duramycin-induced calcium release in cancer cells.

Duramycin, through binding with phosphatidylethanolamine (PE), has shown potential to be an effective antitumour agent. However, its mode of action in relation to tumour cells is not fully understood. PE expression on the surface of a panel of cancer cell lines was analysed using duramycin and subsequent antibody labelling, and then analysed by flow cytometry. Cell viability was also assessed by flow cytometry using annexin V and propidium iodide. Calcium ion (Ca) release by tumour cells in response to duramycin was determined by spectrofluorometry following incubation with Fluo-3, AM. Confocal microscopy was performed on the cancer cell line AsPC-1 to assess real-time cell response to duramycin treatment. Duramycin could detect cell surface PE expression on all 15 cancer cell lines screened, which was shown to be duramycin concentration dependent. However, higher concentrations induced necrotic cell death. Duramycin induced calcium ion (Ca) release from the cancer cell lines also in a concentration-dependent and time-dependent manner. Confocal microscopy showed an influx of propidium iodide into the cells over time and induced morphological changes. Duramycin induces Ca release from cancer cell lines in a time-dependent and concentration-dependent manner.