The Effect of Reactive Oxygen Species on Respiratory Complex I Activity in Liposomes.

Respiratory complex I (R-CI) is an essential enzyme in the mitochondrial electron transport chain but also a major source of reactive oxygen species (ROS), which are implicated in neurodegenerative diseases and ageing. While the mechanism of ROS production by R-CI is well-established, the feedback of ROS on R-CI activity is poorly understood. Here, we perform EPR spectroscopy on R-CI incorporated in artificial membrane vesicles to reveal that ROS (particularly hydroxyl radicals) reduce R-CI activity by making the membrane more polar and by increasing its hydrogen bonding capability. Moreover, the mechanism that we have uncovered reveals that the feedback of ROS on R-CI activity via the membrane is transient and not permanent; lipid peroxidation is negligible for the levels of ROS generated under these conditions. Our successful use of modular proteoliposome systems in conjunction with EPR spectroscopy and other biophysical techniques is a powerful approach for investigating ROS effects on other membrane proteins.

Molecular mechanism of the ischemia-induced regulatory switch in mammalian complex I.

Respiratory complex I is an efficient driver for oxidative phosphorylation in mammalian mitochondria, but its uncontrolled catalysis under challenging conditions leads to oxidative stress and cellular damage. Ischemic conditions switch complex I from rapid, reversible catalysis into a dormant state that protects upon reoxygenation, but the molecular basis for the switch is unknown. We combined precise biochemical definition of complex I catalysis with high-resolution cryo-electron microscopy structures in the phospholipid bilayer of coupled vesicles to reveal the mechanism of the transition into the dormant state, modulated by membrane interactions. By implementing a versatile membrane system to unite structure and function, attributing catalytic and regulatory properties to specific structural states, we define how a conformational switch in complex I controls its physiological roles.

Phase II Study of Erdafitinib in Patients With Tumors With Fibroblast Growth Factor Receptor Mutations or Fusions: Results From the NCI-MATCH ECOG-ACRIN Trial (EAY131) Subprotocol K2.

PURPOSE: Subprotocol K2 (EAY131-K2) of the NCI-MATCH platform trial was an open-label, single-arm, phase II study designed to evaluate the antitumor efficacy of the oral FGFR1-4 inhibitor, erdafitinib, in patients with tumors harboring FGFR1-4 mutations or fusions. METHODS: Central confirmation of tumor FGFR1-4 mutations or fusions was required for outcome analysis. Patients with urothelial carcinoma were excluded. Enrolled subjects received oral erdafitinib at a starting dose of 8 mg daily continuously until intolerable toxicity or disease progression. The primary end point was objective response rate (ORR) with key secondary end points of safety, progression-free survival (PFS), and overall survival (OS). RESULTS: Thirty-five patients were enrolled, and 25 patients were included in the primary efficacy analysis as prespecified in the protocol. The median age was 61 years, and 52% of subjects had received ≥3 previous lines of therapy. The confirmed ORR was 16% (4 of 25 [90% CI, 5.7 to 33.0], P = .034 against the null rate of 5%). An additional seven patients experienced stable disease as best-confirmed response. Four patients had a prolonged PFS including two with recurrent WHO grade IV, IDH1-/2-wildtype glioblastoma. The median PFS and OS were 3.6 months and 11.0 months, respectively. Erdafitinib was manageable with no new safety signals. CONCLUSION: This study met its primary end point in patients with several pretreated solid tumor types harboring FGFR1-3 mutations or fusions. These findings support advancement of erdafitinib for patients with fibroblast growth factor receptor-altered tumors outside of currently approved indications in a potentially tumor-agnostic manner.

Phase II Study of Erdafitinib in Patients With Tumors With FGFR Amplifications: Results From the NCI-MATCH ECOG-ACRIN Trial (EAY131) Subprotocol K1.

PURPOSE: Despite fibroblast growth factor receptor (FGFR) inhibitors being approved in tumor types with select FGFR rearrangements or gene mutations, amplifications of FGFR represent the most common FGFR alteration across malignancies. Subprotocol K1 (EAY131-K1) of the National Cancer Institute-MATCH platform trial was designed to evaluate the antitumor efficacy of the oral FGFR1-4 inhibitor, erdafitinib, in patients with tumors harboring FGFR1-4 amplification. METHODS: EAY131-K1 was an open-label, single-arm, phase II study with central confirmation of presence of FGFR1-4 amplification in tumors. Patients with urothelial carcinoma were excluded. Enrolled patients received oral erdafitinib at a starting dose of 8 mg once daily continuously with escalation to 9 mg once daily continuously, on the basis of predefined time point assessments of phosphate levels, until disease progression or intolerable toxicity. The primary end point was centrally assessed objective response rate (ORR), with key secondary end points being 6-month progression-free survival (PFS6), PFS, overall survival (OS), and safety. RESULTS: Thirty-five patients were enrolled into this study with 18 included in the prespecified primary efficacy analysis. The median age of the 18 patients was 60 years, and 78% had received ≥3 previous lines of therapy. There were no confirmed responses to erdafitinib; however, five patients experienced stable disease (SD) as best response. One patient with an FGFR1-amplified breast cancer had a prolonged PFS >168 days (5.5 months). The median PFS was 1.7 months (90% CI, 1.1 to 1.8 months) and the median OS was 4.2 months (90% CI, 2.3 to 9.3 months). The estimated PFS6 rate was 13.8% (90% CI, 3.3 to 31.6). The majority of toxicities were grade 1 to 2 in nature, although there was one grade 5 treatment-related adverse event. CONCLUSION: Erdafitinib did not meet its primary end point of efficacy as determined by ORR in treatment-refractory solid tumors harboring FGFR1-4 amplifications. Our findings support that rearrangements and gene mutations, but not amplifications, of FGFR remain the established FGFR alterations with approved indications for FGFR inhibition.

Trastuzumab and Pertuzumab in Patients with Non-Breast/Gastroesophageal HER2-Amplified Tumors: Results from the NCI-MATCH ECOG-ACRIN Trial (EAY131) Subprotocol J.

PURPOSE: NCI-MATCH assigned patients with advanced cancer and progression on prior treatment, based on genomic alterations in pretreatment tumor tissue. Arm J (EAY131-J) evaluated the combination of trastuzumab/pertuzumab (HP) across HER2-amplified tumors. PATIENTS AND METHODS: Eligible patients had high levels of HER2 amplification [copy number (CN) ≥7] detected by central next-generation sequencing (NGS) or through NCI-designated laboratories. Patients with breast/gastroesophageal adenocarcinoma and those who received prior HER2-directed therapy were excluded. Enrollment of patients with colorectal cancer was capped at 4 based on emerging data. Patients received HP IV Q3 weeks until progression or unacceptable toxicity. Primary endpoint was objective response rate (ORR); secondary endpoints included progression-free survival (PFS) and overall survival (OS). RESULTS: Thirty-five patients were enrolled, with 25 included in the primary efficacy analysis (CN ≥7 confirmed by a central lab, median CN = 28). Median age was 66 (range, 31-80), and half of all patients had ≥3 prior therapies (range, 1-11). The confirmed ORR was 12% [3/25 partial responses (colorectal, cholangiocarcinoma, urothelial cancers), 90% confidence interval (CI) 3.4%-28.2%]. There was one additional partial response (urothelial cancer) in a patient with an unconfirmed ERBB2 copy number. Median PFS was 3.3 months (90% CI 2.0-4.1), and median OS 9.4 months (90% CI 5.0-18.9). Treatment-emergent adverse events were consistent with prior studies. There was no association between HER2 CN and response. CONCLUSIONS: HP was active in a selection of HER2-amplified tumors (non-breast/gastroesophageal) but did not meet the predefined efficacy benchmark. Additional strategies targeting HER2 and potential resistance pathways are warranted, especially in rare tumors.

Using light scattering to assess how phospholipid-protein interactions affect complex I functionality in liposomes.

Complex I is an essential membrane protein in respiration, oxidising NADH and reducing ubiquinone to contribute to the proton-motive force that powers ATP synthesis. Liposomes provide an attractive platform to investigate complex I in a phospholipid membrane with the native hydrophobic ubiquinone substrate and proton transport across the membrane, but without convoluting contributions from other proteins present in the native mitochondrial inner membrane. Here, we use dynamic and electrophoretic light scattering techniques (DLS and ELS) to show how physical parameters, in particular the zeta potential (ζ-potential), correlate strongly with the biochemical functionality of complex I-containing proteoliposomes. We find that cardiolipin plays a crucial role in the reconstitution and functioning of complex I and that, as a highly charged lipid, it acts as a sensitive reporter on the biochemical competence of proteoliposomes in ELS measurements. We show that the change in ζ-potential between liposomes and proteoliposomes correlates linearly with protein retention and catalytic oxidoreduction activity of complex I. These correlations are dependent on the presence of cardiolipin, but are otherwise independent of the liposome lipid composition. Moreover, changes in the ζ-potential are sensitive to the proton motive force established upon proton pumping by complex I, thereby constituting a complementary technique to established biochemical assays. ELS measurements may thus serve as a more widely useful tool to investigate membrane proteins in lipid systems, especially those that contain charged lipids.

Pain management for medical abortion before 14 weeks' gestation: A systematic review.

INTRODUCTION: Abortion is common worldwide and increasingly abortions are performed at less than 14 weeks' gestation using medical methods, specifically using a combination of mifepristone and misoprostol. Medical abortion is known to be a painful process, but the optimal method of pain management is unclear. We sought to identify and compare pain management regimens for medical abortion before 14 weeks' gestation. STUDY DESIGN: We conducted our search in August 2019 and included randomized controlled trials (RCT) and observational studies of any pain relief intervention (pharmacological and non-pharmacological) for mifepristone-misoprostol combination medical abortion of pregnancies less than 14 weeks' gestation. RESULTS: We included four RCTs and one observational study. Due to the heterogeneity of study designs, interventions and outcome reporting, meta-analysis was not possible. Only one study found evidence of an effect between interventions on pain score: a prophylactic dose of ibuprofen 1600mg likely reduces the pain score when compared to a dose of paracetamol 2000mg (MD 2.26/10 [CI 3-1.52 lower]). For other interventions (pregabalin 300mg vs placebo; ibuprofen 800mg vs placebo; therapeutic vs prophylactic administration of ibuprofen 800mg; ambulation vs non-ambulation during treatment) there appeared to be little to no difference with comparator. CONCLUSIONS: The findings of this review provide some support for the use of ibuprofen as a single dose given with misoprostol prophylactically, or in response to pain as needed. The optimal dosing of ibuprofen is unclear, but a single dose of ibuprofen 1600mg was shown to be effective and it was less certain whether 800mg was effective.

Making the leap from structure to mechanism: are the open states of mammalian complex I identified by cryoEM resting states or catalytic intermediates?

Respiratory complex I (NADH:ubiquinone oxidoreductase) is a multi-subunit, energy-transducing mitochondrial enzyme that is essential for oxidative phosphorylation and regulating NAD+/NADH pools. Despite recent advances in structural knowledge and a long history of biochemical analyses, the mechanism of redox-coupled proton translocation by complex I remains unknown. Due to its ability to separate molecules in a mixed population into distinct classes, single-particle electron cryomicroscopy has enabled identification and characterisation of different complex I conformations. However, deciding on their catalytic and/or regulatory properties to underpin mechanistic hypotheses, especially without detailed biochemical characterisation of the structural samples, has proven challenging. In this review we explore different mechanistic interpretations of the closed and open states identified in cryoEM analyses of mammalian complex I.

Uptake of long-acting reversible contraception after telemedicine delivered abortion during Covid-19.

BACKGROUND: During COVID-19, early medical abortion (EMA) at home in Scotland was largely delivered by telemedicine. Short-acting post-abortion contraception was provided with EMA medications, but long-acting reversible contraception (LARC) (implant, injectable and intrauterine device) required an in-person visit. We wished to assess LARC uptake following telemedicine abortion, and factors associated with method receipt. METHODS: A prospective observational cohort study of patients accessing abortion via NHS Lothian (October 2020 to February 2021). Patients were offered contraception at telemedicine consultation and their choice was recorded in their clinical notes. Those wishing LARC were directed to the service's rapid-access LARC clinic. We reviewed electronic patient records six weeks post-abortion to determine whether patients received their chosen method. RESULTS: 944 patients had an abortion; 768 (81.4%) had EMA, 131 (13.9%) had a medical or surgical abortion in hospital. The most popular contraceptive method was the progestogen-only pill (n = 324, 34%). 330 patients (35%) requested LARC but less than half (153/330; 46%) received this. Of patients choosing LARC, those who attended the clinic for a pre-abortion ultrasound, or had an abortion in hospital, were more likely to initiate LARC than those having full telemedicine EMA. Nulliparity, gestation over 7 weeks, and age under-26 years were also positively associated with initiating LARC. CONCLUSION: During COVID-19 there was demand for post-abortion LARC but less than half of patients received this by six weeks. Provision was enhanced when in-person clinical interactions took place. Interventions are required to facilitate timely access and initiation of LARC with telemedicine delivered abortion care.

Pain management for medical abortion before 14 weeks' gestation.

BACKGROUND: Abortion is common worldwide and increasingly abortions are performed at less than 14 weeks' gestation using medical methods, specifically using a combination of mifepristone and misoprostol. Medical abortion is known to be a painful process, but the optimal method of pain management is unclear. We sought to identify and compare pain management regimens for medical abortion before 14 weeks' gestation.  OBJECTIVES: Primary objective To determine if there is evidence of superiority of any particular pain relief regimen in the management of combination medical abortion (mifepristone + misoprostol) under 14 weeks' gestation (i.e. up to 13 + 6 weeks or 97 days). Secondary objectives To compare the rate of gastrointestinal side effects resulting from different methods of analgesia To compare the rate of complete abortion resulting from different methods of analgesia during medical abortion To determine if the induction-to-abortion interval is associated with different methods of analgesia To determine if any method of analgesia is associated with unscheduled contact with the care provider in relation to pain. SEARCH METHODS: On 21 August 2019 we searched CENTRAL, MEDLINE, Embase, CINAHL, LILACs, PsycINFO, the World Health Organization International Clinical Trials Registry and ClinicalTrials.gov together with reference checking and handsearching of conference abstracts of relevant learned societies and professional organisations to identify further studies. SELECTION CRITERIA: We included randomised controlled trials (RCTs) and observational studies (non-randomised studies of interventions (NRSIs)) of any pain relief intervention (pharmacological and non-pharmacological) for mifepristone-misoprostol combination medical abortion of pregnancies less than 14 weeks' gestation. DATA COLLECTION AND ANALYSIS: Two review authors (JRW and MA) independently assessed all identified papers for inclusion and risks of bias, resolving any discrepancies through discussion with a third and fourth author as required (CM and SC). Two review authors independently conducted data extraction, including calculations of pain relief scores, and checked for accuracy. We assessed the certainty of the evidence using the GRADE approach. MAIN RESULTS: We included four RCTs and one NRSI. Due to the heterogeneity of study designs, interventions and outcome reporting, we were unable to perform meta-analysis for any of the primary or secondary outcomes in this review. Only one study found evidence of an effect between interventions on pain score: a prophylactic dose of ibuprofen 1600 mg likely reduces the pain score when compared to a dose of paracetamol 2000 mg (mean difference (MD) 2.26 out of 10 lower, 95% confidence interval (CI) 3.00 to 1.52 lower; 1 RCT 108 women; moderate-certainty evidence). There may be little to no difference in pain score when comparing pregabalin 300 mg with placebo (MD 0.5 out of 10 lower, 95% CI 1.41 lower to 0.41 higher; 1 RCT, 107 women; low-certainty evidence).  There may be little to no difference in pain score when comparing ibuprofen 800 mg with placebo (MD 1.4 out of 10 lower, 95% CI 3.33 lower to 0.53 higher; 1 RCT, 61 women; low-certainty evidence). Ambulation or non-ambulation during medical abortion treatment may have little to no effect on pain score, but the evidence is very uncertain (MD 0.1 out of 5 higher, 95% CI 0.26 lower to 0.46 higher; 1 NRSI, 130 women; very low-certainty evidence). There may be little to no difference in pain score when comparing therapeutic versus prophylactic administration of ibuprofen 800 mg (MD 0.2 out of 10 higher, 95% CI 0.41 lower to 0.81 higher; 1 RCT, 228 women; low-certainty evidence).   Other outcomes of interest were reported inconsistently across studies. Where these outcomes were reported, there was no evidence of difference in incidence of gastrointestinal side effects, complete abortion rate, interval between misoprostol administration to pregnancy expulsion, unscheduled contact with a care provider, patient satisfaction with analgesia regimen nor patient satisfaction with abortion experience overall. However, the certainty of evidence was very low to low. AUTHORS' CONCLUSIONS: The findings of this review provide some support for the use of ibuprofen as a single dose given with misoprostol prophylactically, or in response to pain as needed. The optimal dosing of ibuprofen is unclear, but a single dose of ibuprofen 1600 mg was shown to be effective, and it was less certain whether 800 mg was effective. Paracetamol 2000 mg does not improve pain scores as much as ibuprofen 1600 mg, however its use does not appear to cause greater frequency of side effects or reduce the success of the abortion. A single dose of pregabalin 300 mg does not affect pain scores during medical abortion, but like paracetamol, does not appear to cause harm. Ambulation or non-ambulation during the medical abortion procedure does not appear to affect pain scores, outcomes, or duration of treatment and so women can be advised to mobilise or not, as they wish. The majority of outcomes in this review had low- to very low-certainty evidence, primarily due to small sample sizes and two studies at high risk of bias. High-quality, large-scale RCT research is needed for pain management during medical abortion at gestations less than 14 weeks. Consistent recording of pain with a validated measure would be of value to the field going forward.

Cryo-EM structures define ubiquinone-10 binding to mitochondrial complex I and conformational transitions accompanying Q-site occupancy.

Mitochondrial complex I is a central metabolic enzyme that uses the reducing potential of NADH to reduce ubiquinone-10 (Q10) and drive four protons across the inner mitochondrial membrane, powering oxidative phosphorylation. Although many complex I structures are now available, the mechanisms of Q10 reduction and energy transduction remain controversial. Here, we reconstitute mammalian complex I into phospholipid nanodiscs with exogenous Q10. Using cryo-EM, we reveal a Q10 molecule occupying the full length of the Q-binding site in the 'active' (ready-to-go) resting state together with a matching substrate-free structure, and apply molecular dynamics simulations to propose how the charge states of key residues influence the Q10 binding pose. By comparing ligand-bound and ligand-free forms of the 'deactive' resting state (that require reactivating to catalyse), we begin to define how substrate binding restructures the deactive Q-binding site, providing insights into its physiological and mechanistic relevance.

Reverse Electron Transfer by Respiratory Complex I Catalyzed in a Modular Proteoliposome System.

Respiratory complex I is an essential metabolic enzyme that uses the energy from NADH oxidation and ubiquinone reduction to translocate protons across an energy transducing membrane and generate the proton motive force for ATP synthesis. Under specific conditions, complex I can also catalyze the reverse reaction, Δp-linked oxidation of ubiquinol to reduce NAD+ (or O2), known as reverse electron transfer (RET). Oxidative damage by reactive oxygen species generated during RET underpins ischemia reperfusion injury, but as RET relies on several converging metabolic pathways, little is known about its mechanism or regulation. Here, we demonstrate Δp-linked RET through complex I in a synthetic proteoliposome system for the first time, enabling complete kinetic characterization of RET catalysis. We further establish the capability of our system by showing how RET in the mammalian enzyme is regulated by the active-deactive transition and by evaluating RET by complex I from several species in which direct assessment has not been otherwise possible. We thus provide new insights into the reversibility of complex I catalysis, an important but little understood mechanistic and physiological feature.

Phase II Study of Copanlisib in Patients With Tumors With PIK3CA Mutations: Results From the NCI-MATCH ECOG-ACRIN Trial (EAY131) Subprotocol Z1F.

PURPOSE: Activating mutations in PIK3CA are observed across multiple tumor types. The NCI-MATCH (EAY131) is a tumor-agnostic platform trial that enrolls patients to targeted therapies on the basis of matching genomic alterations. Arm Z1F evaluated copanlisib, an α and δ isoform-specific phosphoinositide 3-kinase (PI3K) inhibitor, in patients with PIK3CA mutations (with or without PTEN loss). PATIENTS AND METHODS: Patients received copanlisib (60 mg intravenous) once weekly on days 1, 8, and 15 in 28-day cycles until progression or toxicity. Patients with KRAS mutations, human epidermal growth factor receptor 2-positive breast cancers, and lymphomas were excluded. The primary end point was centrally assessed objective response rate (ORR); secondary end points included progression-free survival, 6-month progression-free survival, and overall survival. RESULTS: Thirty-five patients were enrolled, and 25 patients were included in the primary efficacy analysis as prespecified in the Protocol. Multiple histologies were enrolled, with gynecologic (n = 6) and gastrointestinal (n = 6) being the most common. Sixty-eight percent of patients had ≥ 3 lines of prior therapy. The ORR was 16% (4 of 25, 90% CI, 6 to 33) with P = .0341 against a null rate of 5%. The most common reason for protocol discontinuation was disease progression (n = 17, 68%). Grade 3/4 toxicities observed were consistent with reported toxicities for PI3K pathway inhibition. Sixteen patients (53%) had grade 3 toxicities, and one patient (3%) had grade 4 toxicity (CTCAE v5.0). Most common toxicities include hyperglycemia (n = 19), fatigue (n = 12), diarrhea (n = 11), hypertension (n = 10), and nausea (n = 10). CONCLUSION: The study met its primary end point with an ORR of 16% (P = .0341) with copanlisib showing clinical activity in select tumors with PIK3CA mutation in the refractory setting.

Cabozantinib plus Nivolumab Phase I Expansion Study in Patients with Metastatic Urothelial Carcinoma Refractory to Immune Checkpoint Inhibitor Therapy.

PURPOSE: This study investigated the efficacy and tolerability of cabozantinib plus nivolumab (CaboNivo) in patients with metastatic urothelial carcinoma (mUC) that progressed on checkpoint inhibition (CPI). PATIENTS AND METHODS: A phase I expansion cohort of patients with mUC who received prior CPI was treated with cabozantinib 40 mg/day and nivolumab 3 mg/kg every 2 weeks until disease progression/unacceptable toxicity. The primary goal was objective response rate (ORR) per RECIST v.1.1. Secondary objectives included progression-free survival (PFS), duration of response (DoR), overall survival (OS), safety, and tolerability. RESULTS: Twenty-nine out of 30 patients enrolled were evaluable for efficacy. Median follow-up was 22.2 months. Most patients (86.7%) received prior chemotherapy and all patients received prior CPI (median seven cycles). ORR was 16.0%, with one complete response and three partial responses (PR). Among 4 responders, 2 were primary refractory, 1 had a PR, and 1 had stable disease on prior CPI. Median DoR was 33.5 months [95% confidence interval (CI), 3.7-33.5], median PFS was 3.6 months (95% CI, 2.1-5.5), and median OS was 10.4 months (95% CI, 5.8-19.5). CaboNivo decreased immunosuppressive subsets such as regulatory T cells (Tregs) and increased potential antitumor immune subsets such as nonclassical monocytes and effector T cells. A lower percentage of monocytic myeloid-derived suppressor cells (M-MDSC) and polymorphonuclear MDSCs, lower CTLA-4 and TIM-3 expression on Tregs, and higher effector CD4+ T cells at baseline were associated with better PFS and/or OS. CONCLUSIONS: CaboNivo was clinically active, well tolerated, and favorably modulated peripheral blood immune subsets in patients with mUC refractory to CPI.

Medical Abortion before Confirmed Intrauterine Pregnancy: A Systematic Review.

"Very early medical abortion" (VEMA) refers to medical abortion (with mifepristone and misoprostol) before intrauterine pregnancy is visualized on ultrasound. Our aim is to present the current evidence on efficacy, safety (focused on ectopic pregnancies), and how to assess treatment success of VEMA. We conducted a systematic review of studies reporting outcomes of VEMA. The field is small and so our objective was to map all relevant literature, without conducting meta-analysis. We searched PubMed, Medline, and Embase on April 19, 2022. We conducted a narrative synthesis of the evidence. A total of 373 articles were identified. Six articles (representing four observational and one pilot trial) were included in the final review. Across all included studies, treatment efficacy ranged between 91 and 100%. Prevalence of ectopic pregnancy was low and very few cases (n = 2) of ruptures were reported. Most studies used serial serum human chorionic gonadotrophin (s-hCG) levels to determine success of abortion; one study used low sensitivity urine hCG. From the available evidence, VEMA appears to be efficacious and does not appear to cause harm to ectopic pregnancies. Treatment can be assessed with pre- and postabortion s-hCG. Good quality, randomized controlled trial evidence is needed to best inform practice.

Clinical Activity of Single-Agent Cabozantinib (XL184), a Multi-receptor Tyrosine Kinase Inhibitor, in Patients with Refractory Soft-Tissue Sarcomas.

PURPOSE: Soft-tissue sarcomas (STS) are a rare, heterogeneous group of mesenchymal tumors. For decades the mainstay of treatment for advanced, unresectable STS has been palliative chemotherapy. High levels of activated MET receptor have been reported in various sarcoma cell lines, together with elevated vascular endothelial growth factor (VEGF) levels in patients with STS, suggesting that dual targeting of the VEGF and MET pathways with the multi-receptor tyrosine kinase inhibitor cabozantinib would result in clinical benefit in this population. PATIENTS AND METHODS: We performed an open-label, multi-institution, single-arm phase II trial of single-agent cabozantinib in adult patients with advanced STS and progressive disease after at least 1 standard line of systemic therapy. Patients received 60 mg oral cabozantinib once daily in 28-day cycles, and dual primary endpoints of overall response rate and 6-month progression-free survival (PFS) were assessed. Changes in several circulating biomarkers were assessed as secondary endpoints. RESULTS: Six (11.1%; 95% CI, 4.2%-22.6%) of the 54 evaluable patients enrolled experienced objective responses (all partial responses). Six-month PFS was 49.3% (95% CI, 36.2%-67.3%), with a median time on study of 4 cycles (range, 1-99). The most common grade 3/4 adverse events were hypertension (7.4%) and neutropenia (16.7%). Patients' levels of circulating hepatocyte growth factor (HGF), soluble MET, and VEGF-A generally increased after a cycle of therapy, while soluble VEGFR2 levels decreased, regardless of clinical outcome. CONCLUSIONS: Cabozantinib single-agent antitumor activity was observed in patients with selected STS histologic subtypes (alveolar soft-part sarcoma, undifferentiated pleomorphic sarcoma, extraskeletal myxoid chondrosarcoma, and leiomyosarcoma) highlighting the biomolecular diversity of STS.

Utility of a routine ultrasound for detection of ectopic pregnancies among women requesting abortion: a retrospective review.

INTRODUCTION: Routine ultrasound may be used in abortion services to determine gestational age and confirm an intrauterine pregnancy. However, ultrasound adds complexity to care and results may be inconclusive, delaying abortion. We sought to determine the rate of ectopic pregnancy and the utility of routine ultrasound in its detection, in a community abortion service. METHODS: Retrospective case record review of women requesting abortion over a 5-year period (2015-2019) with an outcome of ectopic pregnancy or pregnancy of unknown location (PUL) at a service (Edinburgh, UK) conducting routine ultrasound on all women. Records were searched for symptoms at presentation, development of symptoms during clinical care, significant risk factors and routine ultrasound findings. RESULTS: Only 29/11 381 women (0.25%, 95% CI 0.18%, 0.33%) had an ectopic pregnancy or PUL (tubal=18, caesarean scar=1, heterotopic=1, PUL=9). Eleven (38%) cases had either symptoms at presentation (n=8) and/or significant risk factors for ectopic pregnancy (n=4). A further 12 women developed symptoms during their clinical care. Of the remaining six, three were PUL treated with methotrexate and three were ectopic (salpingectomy=2, methotrexate=1). In three cases, the baseline ultrasound indicated a probable early intrauterine pregnancy. CONCLUSIONS: Ectopic pregnancies are uncommon among women presenting for abortion. The value of routine ultrasound in excluding ectopic pregnancy in symptom-free women without significant risk factors is questionable as it may aid detection of some cases but may provide false reassurance that a pregnancy is intrauterine.

Functional basis of electron transport within photosynthetic complex I.

Photosynthesis and respiration rely upon a proton gradient to produce ATP. In photosynthesis, the Respiratory Complex I homologue, Photosynthetic Complex I (PS-CI) is proposed to couple ferredoxin oxidation and plastoquinone reduction to proton pumping across thylakoid membranes. However, little is known about the PS-CI molecular mechanism and attempts to understand its function have previously been frustrated by its large size and high lability. Here, we overcome these challenges by pushing the limits in sample size and spectroscopic sensitivity, to determine arguably the most important property of any electron transport enzyme - the reduction potentials of its cofactors, in this case the iron-sulphur clusters of PS-CI (N0, N1 and N2), and unambiguously assign them to the structure using double electron-electron resonance. We have thus determined the bioenergetics of the electron transfer relay and provide insight into the mechanism of PS-CI, laying the foundations for understanding of how this important bioenergetic complex functions.

Combination therapy with pazopanib and tivantinib modulates VEGF and c-MET levels in refractory advanced solid tumors.

The vascular endothelial growth factor (VEGF)/VEGFR and hepatocyte growth factor (HGF)/c-MET signaling pathways act synergistically to promote angiogenesis. Studies indicate VEGF inhibition leads to increased levels of phosphorylated c-MET, bypassing VEGF-mediated angiogenesis and leading to chemoresistance. We conducted a phase 1 clinical trial with 32 patients with refractory solid tumors to evaluate the safety, pharmacokinetics, and pharmacodynamics of combinations of VEGF-targeting pazopanib and the putative c-MET inhibitor ARQ197 (tivantinib) at 5 dose levels (DLs). Patients either took pazopanib and tivantinib from treatment initiation (escalation phase) or pazopanib alone for 7 days, with paired tumor sampling, prior to starting combination treatment (expansion phase). Hypertension was the most common adverse event. No more than 1 dose limiting toxicity (DLT) occurred at any DL, so the maximum tolerated dose (MTD) was not determined; DL5 (800 mg pazopanib daily and 360 mg tivantinib BID) was used during the expansion phase. Twenty of 31 evaluable patients achieved stable disease lasting up to 22 cycles. Circulating VEGF, VEGFR2, HGF, and c-MET levels were assessed, and only VEGF levels increased. Tumor c-MET levels (total and phosphorylated) were determined in paired biopsies before and after 7 days of pazopanib treatment. Total intact c-MET decreased in 6 of 7 biopsy pairs, in contrast to previously reported c-MET elevation in response to VEGF inhibition. These results are discussed in the context of our previously reported analysis of epithelial-mesenchymal transition in these tumors.