Understanding Reaction Pathways in High Dielectric Electrolytes Using β-Mo2C as a Catalyst for Li-CO2 Batteries

The rechargeable Li-CO₂ battery has attracted considerable attention in recent years because of its carbon dioxide (CO₂) utilization and because it represents a practical Li-air battery. As with other battery systems such as the Li-ion, Li-O₂, and Li-S battery systems, understanding the reaction pathway is the first step to achieving high battery performance because the performance is strongly affected by reaction intermediates. Despite intensive efforts in this area, the effect of material parameters (e.g., the electrolyte, the cathode, and the catalyst) on the reaction pathway in Li-CO₂ batteries is not yet fully understood. Here, we show for the first time that the discharge reaction pathway of a Li-CO₂ battery composed of graphene nanoplatelets/beta phase of molybdenum carbide (GNPs/β-Mo₂C) is strongly influenced by the dielectric constant of its electrolyte. Calculations using the continuum solvents model show that the energy of adsorption of oxalate (C₂O₄^2-) onto Mo₂C under the low-dielectric electrolyte tetraethylene glycol dimethyl ether is lower than that under the high-dielectric electrolyte N,N-dimethylacetamide (DMA), indicating that the electrolyte plays a critical role in determining the reaction pathway. The experimental results show that under the high-dielectric DMA electrolyte, the formation of lithium carbonate (Li₂CO₃) as a discharge product is favorable because of the instability of the oxalate species, confirming that the dielectric properties of the electrolyte play an important role in the formation of the discharge product. The resulting Li-CO₂ battery exhibits improved battery performance, including a reduced overpotential and a remarkable discharge capacity as high as 14,000 mA h g^-1 because of its lower internal resistance. We believe that this work provides insights for the design of Li-CO₂ batteries with enhanced performance for practical Li-air battery applications.

Cyclin E1 and cyclin E2 in ER+ breast cancer: prospects as biomarkers and therapeutic targets

Cyclin E1 is one the most promising biomarkers in estrogen receptor positive (ER+) breast cancer for response to the new standard of care drug class, CDK4/6 inhibitors. Because of its strong predictive value, cyclin E1 expression may be used in the future to triage patients into potential responders and non-responders. Importantly, cyclin E1 is highly related to cyclin E2, and both cyclin E1 and cyclin E2 are estrogen target genes that can facilitate anti-estrogen resistance and can be highly expressed in breast cancer. However cyclin E1 and E2 are often expressed in different subsets of patients. This raises questions about whether the expression of cyclin E1 and cyclin E2 have different biological drivers, if high expressing subsets represent different clinical subtypes, and how to effectively develop a biomarker for E-cyclin expression. Finally, several pan-CDK inhibitors that target cyclin E-CDK2 activity have reached Phase II clinical trials. In this review, we outline the data identifying that different cohorts of patients have high expression of cyclins E1 and E2 in ER+ cancer and address the implications for biomarker and therapeutic development.

Does Exposure to Computed Tomography Contrast Media Increase Risk of End-Stage Renal Disease?

Background

There are many studies on acute kidney injury (AKI) after exposure to contrast media in patients with chronic kidney disease (CKD). However, whether the risk of end-stage renal disease (ESRD) increases after exposure to contrast media in the long term, regardless of development of AKI after such exposure, has not been studied.

Material/Methods

The electronic health records of patients diagnosed with CKD and followed up from 2014 to 2018 at a tertiary university hospital were retrospectively collected. Patients were divided into patients who progressed to ESRD (ESRD group) and those who did not (non-ESRD group). Patients in the non-ESRD group were matched 1: 1 to those in the ESRD group by using disease risk score generation and matching. Multivariate logistic regression analysis was performed to assess the effect of contrast media exposure on progression to ESRD.

Results

In total, 179 patients were enrolled per group; 178 (99.4%) were in CKD stage 3 or above in both groups. Average serum creatinine was 4.31±3.02 mg/dl and 3.64±2.55 mg/dl in the ESRD and non-ESRD groups, respectively (p=0.242). Other baseline characteristics were not statistically significant, except for the number of times contrast-enhanced computed tomography (CECT) was performed (0.00 [Interquartile range (IQR) 0.00–2.00] in the ESRD group and 0.00 [IQR 0.00–1.00] in the non-ESRD group [p=0.006]); in multivariate logistic regression, this number (OR=1.24, 95% CI=1.08–1.47, p=0.006) was significantly related to progression to ESRD.

Conclusions

The use of CECT increased the risk of ESRD 1.2-fold in advanced and stable CKD outpatients after 5-year follow-up.

Congenital adrenal hyperplasia presenting as pelvic inflammatory disease in a phenotypic male: A case report

RATIONALE

Congenital adrenal hyperplasia (CAH) is caused by various enzyme deficiencies, among which 21-hydroxylase (21-OH) deficiency accounts for more than 90% of cases. Neonatal screening became mandatory only a few decades ago. Many patients who were born before this went undiagnosed and some of the severely virilized females were raised as men.

PATIENT CONCERNS

A 58-year old man with a history of excisional surgery in the external genitalia when he was a toddler presented with three days of dysuria and low abdominal pain.

DIAGNOSIS

The patient's laboratory results showed leukocytosis and elevated C-reactive protein (CRP); thus, the physicians decided to perform a computed tomography (CT) scan. The CT demonstrated pelvic inflammatory disease (PID), left adrenal gland myelolipoma, and a mesenteric mass. Meanwhile, we suspected CAH based on the clinical history and assessed the patient's hormone levels. Seventeen-hydroxyprogesterone (17-OH-PG) was markedly elevated and the patient was diagnosed with classic simple virilizing CAH.

INTERVENTIONS

Intravenous antibiotics were administered, and positron emission tomography-CT (PET-CT) was performed to evaluate any metastases.

OUTCOMES

After 2 weeks of antibiotic treatment, CRP decreased to 0.12 mg/dL and PID was resolved. The patient opted for resection of the female genitalia along with the mesenteric and adrenal gland tumors in the near future, and was safely discharged.

LESSONS

The adrenal gland myelolipoma was thought to have developed as a result of a longstanding exposure to adrenocorticotropic hormone. There are controversies regarding the management of female genitalia in CAH patients who identify themselves as men. In this case, the physician and patient decided to remove the female genitalia because the surgery for the mesenteric mass was inevitable and there was a possibility of recurrent PID. To our knowledge, this is the first article to report primary mesenteric tumor in a CAH patient to date. In conclusion, patients who were born before neonatal screening for CAH became the mainstay, who are suspected to have CAH from their history, and present with abdominal pain must be diagnosed by performing an imaging study, testing levels of serum 17-OH-PG, and screening for female genitalia and adrenal gland myelolipoma.

Optimal cut-off value of high-sensitivity troponin I in diagnosing myocardial infarction in patients with end-stage renal disease

End-stage renal disease (ESRD) is a major risk factor for cardiovascular disease and the prognosis after myocardial infarction (MI) is dismal. Although cardiac troponin is a key diagnostic test, troponin levels are often elevated in ESRD patients without evidence of MI. Thus, this study attempted to determine the optimal diagnostic value of high-sensitivity troponin I (hsTnI) by dialysis modality in ESRD patients.Medical records of adult dialysis patients who visited tertiary emergency department (ED) were collected retrospectively. Diagnosis of MI was made according to the fourth universal definition of MI. The cut-off values were calculated using a receiver operating characteristic (ROC) curve.Medical records of 1144 patients were analyzed and MI was diagnosed in 82 patients (75 on hemodialysis and 7 on peritoneal dialysis). The optimal cut-off value of hsTnI in hemodialysis patients was 75 ng/L, with 93.33% sensitivity and 60.76% specificity. Area under the curve (AUC) was .870 (95% confidence interval (CI) .833-.906). The optimal cut-off value of hsTnI in peritoneal dialysis patients was 144 ng/L, with 100.00% sensitivity and 83.10% specificity. AUC was .943 (95% CI .893-.992).The dialysis modality should also be considered when diagnosing MI using hsTnI in ESRD patients.

Pre-clinical endodontic education outcomes between artificial versus extracted natural teeth: a systematic review

AIM

To compare the educational outcomes using artificial teeth versus extracted teeth for pre-clinical endodontic training.

DATA SOURCES

Literature searches of PubMed, Scopus, Cochrane Library, Trip Database, Web of Science and Open Grey databases were conducted from their inception until November 2018 with no language restriction. Hand searching of most likely relevant journals was performed. The review followed the PRISMA guidelines.

STUDY ELIGIBILITY CRITERIA, PARTICIPANTS AND INTERVENTIONS

Studies that compared pre-clinical endodontic training using extracted teeth and artificial teeth were included.

STUDY APPRAISAL AND SYNTHESIS METHODS

The quality of included studies was appraised by Joanna Briggs Institute Critical Appraisal tools. The findings were tabulated and summarized according to their outcomes with distinct narrative syntheses.

RESULTS

Five studies were included. The component studies included 359 operators in total, mainly consisting of undergraduate students (97%, n = 349) and 10 endodontists (3%). Forty-seven per cent (n = 170) operated on artificial teeth only, whilst 19% (n = 67) worked primarily on extracted teeth, with the final treatment outcome being evaluated by independent observers using objective criteria. Operators in two studies (34%, n = 122) used both artificial teeth and ET and compared their experiences in surveys. Regarding technical outcomes, no significant differences between training with artificial teeth and extracted teeth were found, but the performance tended to be better in artificial teeth than extracted teeth. Operators trained solely on artificial teeth appeared to be adequately educated for subsequent root canal treatment (RCT) in the clinical setting.

LIMITATIONS

Due to the scarcity of research on the topic overall, and the methodological variation between the studies, it was not possible to perform a quantitative analysis (meta-analysis).

CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS

Based on the available evidence, the use of artificial teeth for pre-clinical endodontic training achieved similar educational outcomes compared to extracted teeth. However, the experiences reported by the operators diverged. Further studies assessing other artificial teeth available in the market testing other RCT procedures are necessary.

Abstract P6-21-05: Concurrent exercise and chemotherapy in preclinical breast cancer models

The benefits of exercise following a cancer diagnosis is increasingly recognized. Increased physical activity is associated with reduced breast cancer recurrence and breast cancer specific mortality. However, the mechanisms underpinning this effect are still under investigation. The role of exercise as an adjunct to systemic therapy for breast cancer remains unclear. We hypothesize that exercise may exert an anti-tumor effect and a change in tumor immune cell infiltration.

Methods

We evaluated the effect of exercise alone and in combination with chemotherapy in preclinical patient-derived TNBC xenografts (PDX) established in Nude mice and PyMT mouse tumor models. Mice were individually housed in boxes equipped with running wheels and randomized to 1) clamped wheels (sedentary controls), 2) doxorubicin (Dox, 2mg/kg/week), 3) exercise (Ex) and 4) Ex + Dox. Daily distance run was measured. One week after randomization (acclimatization period), the intervention was commenced. Body composition was measured at randomization and at end point. Tumors were harvested after 5 weeks of intervention or at ethical endpoint. Tumor immune infiltrates were analyzed, and transcriptomic analysis performed.

Results

In the TNBC PDX model, there was no difference in tumor volume at randomization (p=0.96), or cumulative distance run after 1 week of acclimatization to the running wheel (p=0.47). At 5 weeks, Ex alone significantly reduced tumor growth rate compared with controls (relative reduction 10%, p=0.025). There was no difference between the other interventions. Mice randomized to Ex + Dox ran a shorter cumulative distance over 5 weeks compared with Ex alone (103.6 ± 16.2km vs 168.8 ±23km, p=0.028). There was no correlation between distance run and tumor volume in either of the treatment cohorts involving exercise (p=0.39). PyMT, transcriptomic and immune cell infiltration analysis will be reported.

At baseline, there was no significant difference in mean total body mass (TBM), lean mass (LM) or fat mass (FM) between the intervention groups (p>0.05). At 5 weeks, the mean TBM and LM in both groups treated with Dox was significantly lower than Ex only and controls. The Ex and the control mice gained weight (11%), compared with Dox only and Ex + Dox mice which did not gain weight (0% and -6% respectively). Therefore exercise had no significant impact on TBM or LM at 5 weeks, but Dox resulted in loss of TBM and LM compared with mice not treated with Dox.

Conclusion

Exercise significantly reduced tumor growth compared with sedentary controls in our preclinical TNBC PDX model, however there was not synergistic effect seen with Dox. Cumulative doses of Dox resulted in weight loss and loss of lean mass, and reduced the cumulative running distance, compared with mice not treated with Dox.

Citation Format: Wahlroos S, Wilkinson A, Gallego-Ortega D, Febbraio M, Lim E. Concurrent exercise and chemotherapy in preclinical breast cancer models [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-21-05.

Abstract P6-20-04: Activation of AR inhibits growth of endocrine-resistant breast cancer

Introduction

Resistance to endocrine therapy is a major clinical problem in estrogen receptor positive (ER+) breast cancer. The androgen receptor (AR) is expressed in ˜90% of all ER+ breast cancers and high expression of AR is associated with a better patient outcome in this subtype. In agreement, AR activation in breast cancer cell line models reduces proliferation of cells via antagonism of ER signaling. However, uncertainty surrounding the role of AR in endocrine resistance is reflected in current clinical trials in which both AR agonists and antagonists are being investigated. In this study, we sought to investigate the optimal approach in targeting AR in endocrine-resistant breast cancer.

Methods

We evaluated the consequences of AR activation, using AR cognate ligand 5α-dihydrotestosterone (DHT) and selective AR modulator enobosarm, and AR antagonism using enzalutamide on in vitro and in vivo models of endocrine-resistance. The efficacy of these AR modulators were assessed in vitro using tamoxifen-resistant (TamR) and long-term estrogen derived (LTED) models of MCF7 cells, and in vivo using ESR1 mutant E2-dependent (HCI-005) and ESR1 wild-type E2-independent (Gar15-13) endocrine-resistant PDX models

Results

Treatment with DHT and enobosarm inhibited the growth of MCF7 TamR and LTED cells but enzalutamide had no effect. AR activation was associated with loss of ER in MCF7 TamR cells and loss of ER-regulated PR expression in MCF7 LTED which suggests that this growth suppression was mediated through the antagonism of ER signaling. Notably, an additive anti-proliferative effect was observed with the combination of enobosarm and CDK4/6 inhibitor palbocilib in the MCF7 TamR cells. A similar pattern was observed in vivo with DHT strongly inhibiting the proliferation of both PDX models. Enobosarm similarly suppressed the proliferation of HCI-005, and to a lesser extent in Gar15-13. The benefit of enobosarm in Gar15-13 was significant given that this model is fulvestrant-resistant. Antagonizing AR with enzalutamide had no effect on growth of Gar15-13 model, similar to our in vitro data. AR agonists reduced expression levels of ER and PR in HCI-005, and transcriptomic analysis of AR agonist-treated Gar15-13 identified significant negative enrichment of genes related to proliferation and estrogen response. These observations indicate that the growth-suppressive effects of AR activation in vivo were mediated through inhibiting ER signaling. We identified an AR gene signature, through RNA-seq analysis of DHT-treated Gar15-13 PDX, which is strongly associated with good outcome in the METABRIC dataset, supporting the hypothesis that an active canonical AR signaling is tumor suppressive in both endocrine-sensitive and -resistant disease contexts. Lastly, we present in vivo data demonstrating enhanced suppression of Ki-67 with the combination of enobosarm and palbociclib in the Gar15-13 PDX.

Conclusion

We have demonstrated that activating AR is an effective therapeutic approach in endocrine-resistant breast cancer, and the combination of an AR agonist with a CDK4/6 inhibitor warrants further investigation in this breast cancer subtype.

Citation Format: Chia KM, Milioli H, Portman N, Laven-Law G, Yong A, Swarbrick A, Caldon L, Tilley W, Hickey T, Lim E. Activation of AR inhibits growth of endocrine-resistant breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-20-04.

Abstract P5-07-03: Small molecule inhibition of smoothened in triple negative breast cancer-associated fibroblasts depletes cancer stem cells and sensitizes to cytotoxic chemotherapy in mice and humans

The cellular and molecular basis of stromal cell recruitment, activation and crosstalk in carcinomas is poorly understood, limiting the development of targeted anti-stromal therapies.

In mouse models of triple negative breast cancer (TNBC), we use single cell genomics to show that Hh ligand produced by neoplastic cells reprograms cancer-associated fibroblast (CAF) gene expression, driving tumor growth and metastasis. Hh-activated CAFs upregulated expression of FGF5 and deposition of fibrillar collagen, leading to FGFR and FAK activation in adjacent neoplastic cells and the acquisition of a stem-like, drug-resistant phenotype.

Treatment with smoothened inhibitors (SMOi) reversed these phenotypes. Stromal treatment of TNBC patient-derived xenograft (PDX) models with SMOi downregulated the expression of cancer stem cell markers and sensitized tumors to docetaxel, leading to markedly improved survival and reduced metastatic burden.

In the phase I clinical trial EDALINE, 3 patients with metastatic TNBC derived clinical benefit from combination therapy with the SMOi Sonedigib and docetaxel chemotherapy, with one patient experiencing a complete radiological response. Responders also exhibited high baseline FGFR activation and ECM deposition, suggesting a mechanism of action consistent with findings from the animal models.

These studies identify Hh signaling to CAFs as a novel mediator of cancer stem cell plasticity and drug resistance and an exciting new therapeutic target in TNBC.

Citation Format: Swarbrick A, Cazet A, Hui M, O'Toole S, Lim E, Martin M. Small molecule inhibition of smoothened in triple negative breast cancer-associated fibroblasts depletes cancer stem cells and sensitizes to cytotoxic chemotherapy in mice and humans [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-07-03.