Targeting Fatty Acid Oxidation to Promote Anoikis and Inhibit Ovarian Cancer Progression

Epithelial-derived high-grade serous ovarian cancer (HGSOC) is the deadliest gynecologic malignancy. Roughly 80% of patients are diagnosed with late-stage disease, which is defined by wide-spread cancer dissemination throughout the pelvic and peritoneal cavities. HGSOC dissemination is dependent on tumor cells acquiring the ability to resist anoikis (apoptosis triggered by cell detachment). Epithelial cell detachment from the underlying basement membrane or extracellular matrix leads to cellular stress, including nutrient deprivation. In this report, we examined the contribution of fatty acid oxidation (FAO) in supporting anoikis resistance. We examined expression Carnitine Palmitoyltransferase 1A (CPT1A) in a panel of HGSOC cell lines cultured in adherent and suspension conditions. With CPT1A knockdown cells, we evaluated anoikis by caspase 3/7 activity, cleaved caspase 3 immunofluorescence, flow cytometry, and colony formation. We assessed CPT1A-dependent mitochondrial activity and tested the effect of exogenous oleic acid on anoikis and mitochondrial activity. In a patient-derived xenograft model, we administered etomoxir, an FAO inhibitor, and/or platinum-based chemotherapy. CPT1A is overexpressed in HGSOC, correlates with poor overall survival, and is upregulated in HGSOC cells cultured in suspension. CPT1A knockdown promoted anoikis and reduced viability of cells cultured in suspension. HGSOC cells in suspension culture are dependent on CPT1A for mitochondrial activity. In a patient-derived xenograft model of HGSOC, etomoxir significantly inhibited tumor progression. IMPLICATIONS: Targeting FAO in HGSOC to promote anoikis and attenuate dissemination is a potential approach to promote a more durable antitumor response and improve patient outcomes.

Multi-Omic Approaches Identify Metabolic and Autophagy Regulators Important in Ovarian Cancer Dissemination

High-grade serous ovarian cancers (HGSOCs) arise from exfoliation of transformed cells from the fallopian tube, indicating that survival in suspension, and potentially escape from anoikis, is required for dissemination. We report here the results of a multi-omic study to identify drivers of anoikis escape, including transcriptomic analysis, global non-targeted metabolomics, and a genome-wide CRISPR/Cas9 knockout (GeCKO) screen of HGSOC cells cultured in adherent and suspension settings. Our combined approach identified known pathways, including NOTCH signaling, as well as novel regulators of anoikis escape. Newly identified genes include effectors of fatty acid metabolism, ACADVL and ECHDC2, and an autophagy regulator, ULK1. Knockdown of these genes significantly inhibited suspension growth of HGSOC cells, and the metabolic profile confirmed the role of fatty acid metabolism in survival in suspension. Integration of our datasets identified an anoikis-escape gene signature that predicts overall survival in many carcinomas.

Short-term morbidity in transdiaphragmatic cardiophrenic lymph node resection for advanced stage gynecologic cancer

Ovarian cancer is commonly diagnosed at an advanced stage, with disease involving the upper abdomen. The finding of enlarged cardiophrenic lymph nodes (CPLNs) on pre-operative imaging often indicates the presence of malignant spread to the mediastinum. Surgical resection of CPLN through a transdiaphragmatic approach can help to achieve cytoreduction to no gross residual. A retrospective chart review was conducted on all patients who underwent transdiaphragmatic cardiophrenic lymph node resection from 8/1/11 through 2/1/15. All relevant pre-, intra-, and post-operative characteristics and findings were recorded. A brief description of the surgical technique is included for reference. Eleven patients were identified who had undergone transdiaphragmatic resection of cardiophrenic lymph nodes. Malignancy was identified in 18/21 (86%) of total lymph nodes submitted. The median number of post-operative days was 7. The overall post-operative morbidity associated with CPLN resection was low, with the most common finding being a small pleural effusion present on chest x-ray between POD# 3–5 (55%). Transdiaphragmatic CPLN resection is a feasible procedure with relatively minor short-term post-operative morbidities that can be used to achieve cytoreduction to no gross residual disease.

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Pre-operative chest CT can help to identify enlarged cardiophrenic lymph nodes.

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The technique of transdiaphragmatic cardiophrenic lymph node resection is described.

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Resection of CPLNs aids in achieving cytoreduction to no gross residual disease.

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The short-term morbidities associated with the procedure are relatively minor.

Scope of practice and autonomy of physician assistants in rural versus urban emergency departments

OBJECTIVES

This was a study of the scope of practice and autonomy of emergency medicine (EM) physician assistants (PAs) practicing in rural versus urban emergency departments (EDs).

METHODS

Using the American Academy of Physician Assistants (AAPA) Masterfile, a random sample of 200 U.S. EM PAs were surveyed, with oversampling of an additional 200 rural PAs. Location was classified by zip code-based rural-urban commuting area codes, and responses were compared about conditions managed, procedures performed, and physician supervision between rural versus urban groups.

RESULTS

A total of 237 responses were received from PAs in 44 U.S. states, of which (201) were valid responses (105 rural, 96 urban) from PAs currently practicing in EDs (59.3% exclusion-adjusted response rate). Compared to urban PAs, rural PAs more frequently managed cardiac arrest (67% vs. 44%), stroke (86% vs. 72%), multisystem trauma (83% vs. 70%), active labor (44% vs. 23%), and critically ill children (82% vs. 65%) in the past year. They were more likely to have performed intubation (65% vs. 44%), needle thoracostomy (21% vs. 8%), and tube thoracostomy (46% vs. 26%). Rural PAs more often reported never having a physician present in the ED (38% vs. 0%) and less often reported always having a physician present (50% vs. 98%). Rural PAs were also less likely to report that a physician evaluates more than 75% of their patients (8% vs. 18%) and more likely that a physician never evaluates all of their patients (19% vs. 7%).

CONCLUSIONS

Rural PAs reported a broader scope of practice, more autonomy, and less access to physician supervision than urban PAs.