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.

Abstract GS1-01: Landscape of the breast tumour microenvironment at single-cell resolution

Breast cancers are a complex 'ecosystem' of diverse cell types, whose heterotypic interactions play central roles in defining the aetiology of disease and its response to therapy. The next generation of therapies will likely be based upon an integrated understanding of the malignant, microenvironmental and immune states that define the tumour and inform treatment response. However, our poor understanding of the tumour microenvironment (TME) of breast cancers has limited the development and implementation of new drugs that target stromal and immune cells.

Single cell genomics (SCG) is a remarkable new platform to examine the compositional, gene expression and other parameters of thousands of cells, rapidly and at scale. We have used a multi-dimensional SCG approach to characterise the TME in a unique cohort of early and metastatic breast cancers with rich clinico-pathological annotation. We have conducted single cell RNA-Sequencing on more than 125,000 cells collected from 22 patients.

Malignant cells showed remarkable intra-tumoural heterogeneity for canonical breast cancer features, such as intrinsic subtype, hormone receptor expression and activity, drug targets, drug resistance signatures and transcriptional drivers.

Cancer Associated Fibroblasts (CAFs), which are classically studied as a single cell type, were heterogeneous across primary and metastatic sites. Interestingly we identified a myofibroblast-like subset and an inflammatory-mediator subset and propose multi-faceted roles in regulating malignancy and tumour immunity. Distinct transcription factor networks regulated these polarised states.

We applied a new method known as CITE-Seq to measure cell surface immune markers and checkpoint proteins simultaneous to RNA-Sequencing. We resolve the tumour-immune milieu with high precision and generate new transcriptional signatures of breast tumour-infiltrating leukocytes.

To track lymphocyte clonal dynamics through space and time, we developed a novel method known as RAGE-Seq to permit simultaneous full length lymphocyte receptor- and RNA-sequencing at single cell resolution. We observe clonal expansion and trafficking of CD4+ and CD8+ T lymphocytes between the lymph nodes, blood and tumor of patients. In comparison, B cells were polyclonal, suggesting an absence of antigen-dependent clonal expansion.

This data provides by far the most extensive insights into the cellular landscape of breast cancer and will reveal new biomarkers and opportunities for stromal- and immune-based therapy.

Citation Format: Swarbrick A, Wu SZ, Roden D, Al-Eryani G, O'Toole S, Lim E. Landscape of the breast tumour microenvironment at single-cell resolution [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 GS1-01.

Abstract OT1-01-03: The WinPro study: A window of opportunity study of endocrine therapy with and without prometrium in postmenopausal women with early stage hormone receptor-positive breast cancer

Background

There is bidirectional interplay between PR and ER in human breast cancers (Lim et al, Endo Rel Can 2016). There is evidence for a reprogramming of ER chromatin binding sites with 470 genes differentially regulated by dual treatment with estrogen plus progestogen compared to estrogen alone in breast cancer cell lines (Mohammed et al, Nature 2015). Functionally, there was an additive anti-cancer effect with the addition of natural progesterone to endocrine therapy in preclinical breast cancer models.

Trial Design

This is a phase II multi-site, randomised, open-label, three-arm, study in 200 postmenopausal women with early-stage ER+, PR+, HER2-negative breast cancer. Eligible patients will be randomised 1:1:1 to receive 14 days of intervention with either letrozole 2.5mg PO daily (arm 1), letrozole 2.5mg + prometrium 300mg PO daily (arm 2) or tamoxifen 20mg + prometrium 300mg PO daily (arm 3), between diagnosis of breast cancer and definite surgery.

Australian Clinical Trials Registry: ACTRN1261800092813

Eligibility Criteria

Inclusion Criteria

a) Histologically confirmed ER+ and PR+ breast cancers (≥10% positive staining cells)

b) HER2/CEP17 ratio of <2 and mean HER2 copy number <6 (ASCO CAP 2013 guidelines)

c) Tumour size ≥1cm on ultrasound and/or mammogram

d) Aged ≥18 years

Exclusion Criteria

a) Currently on hormone therapies (HRT and OCP)

b) Locally advanced/inoperable and inflammatory breast cancer

c) Clinical evidence of metastatic disease

d) Received other preoperative systemic therapies

e) Nut allergy (prometrium contains peanut oil)

f) Prior history of uterine cancer, deep vein thrombosis, pulmonary embolism or clotting disorder

g) Women who are pregnant/breast feeding

Specific Aims

a) Primary Endpoint

The geometric mean suppression of the centrally assessed proliferation marker Ki67, after two weeks of intervention, compared with baseline. This will be obtained by comparing the mean difference in Ki67 staining between pre and post-treated samples in each intervention arm.

b) Secondary Endpoint

Safety and tolerability of combination therapy (NCI-CTCAE v4.0)

c) Translational Endpoints

1. Define a gene set as a predictive biomarker for a reduction in Ki67

2. Evaluate changes in the apoptotic markers Bcl-2 and Caspase 3 in the tumors following intervention

3. Evaluate changes in ER, PR, AR, FoxA1, Cyclin D1 protein and mRNA expression in the tumors following intervention

Statistical Methods

The IMPACT study reported a geometric mean reduction in Ki67 after 2 weeks of preoperative tamoxifen of 59.5% and anastrazole of 76% (Dowsett et al, JNCI 2007). This allows estimation of power to detect differences between Arm 1 and either Arm 2 or Arm 3 with a p-value of 0.025. For the third possible comparison of Arm 2 vs Arm 3, there is no prior evidence, therefore this as a purely exploratory comparison. With a total trial recruitment of 200 and allowing 4% dropouts, this would give 80% power to detect an improvement in Ki67 suppression from 76% in the letrozole alone control arm to 92% in either experimental arm.

Accrual

Present: 5 (1 site open)

Target: 200 (8 sites total)

Contact Information

Elgene Lim, MBBS, FRACP, PhD. e.lim@garvan.com.au

Citation Format: Carson E, Segara D, Parker A, O'Toole S, Coates A, Mann B, Lindeman G, Tilley W, Lim E. The WinPro study: A window of opportunity study of endocrine therapy with and without prometrium in postmenopausal women with early stage hormone receptor-positive 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 OT1-01-03.

Critical care usage after major gastrointestinal and liver surgery: a prospective, multicentre observational study

BACKGROUND

Patient selection for critical care admission must balance patient safety with optimal resource allocation. This study aimed to determine the relationship between critical care admission, and postoperative mortality after abdominal surgery.

METHODS

This prespecified secondary analysis of a multicentre, prospective, observational study included consecutive patients enrolled in the DISCOVER study from UK and Republic of Ireland undergoing major gastrointestinal and liver surgery between October and December 2014. The primary outcome was 30-day mortality. Multivariate logistic regression was used to explore associations between critical care admission (planned and unplanned) and mortality, and inter-centre variation in critical care admission after emergency laparotomy.

RESULTS

Of 4529 patients included, 37.8% (n=1713) underwent planned critical care admissions from theatre. Some 3.1% (n=86/2816) admitted to ward-level care subsequently underwent unplanned critical care admission. Overall 30-day mortality was 2.9% (n=133/4519), and the risk-adjusted association between 30-day mortality and critical care admission was higher in unplanned [odds ratio (OR): 8.65, 95% confidence interval (CI): 3.51-19.97) than planned admissions (OR: 2.32, 95% CI: 1.43-3.85). Some 26.7% of patients (n=1210/4529) underwent emergency laparotomies. After adjustment, 49.3% (95% CI: 46.8-51.9%, P<0.001) were predicted to have planned critical care admissions, with 7% (n=10/145) of centres outside the 95% CI.

CONCLUSIONS

After risk adjustment, no 30-day survival benefit was identified for either planned or unplanned postoperative admissions to critical care within this cohort. This likely represents appropriate admission of the highest-risk patients. Planned admissions in selected, intermediate-risk patients may present a strategy to mitigate the risk of unplanned admission. Substantial inter-centre variation exists in planned critical care admissions after emergency laparotomies.

Minimally Invasive Bilateral Lung Resections and CABG through 5 Ports

Minimal access surgery is increasingly popular to reduce postoperative morbidity and enhance recovery. We present a case of a patient who underwent bilateral minimally invasive thoracic and cardiac surgery. An 81-year-old woman was diagnosed with T1aN0M0 left upper lobe small-cell lung cancer and underwent single-port left video-assisted thoracoscopic surgery (VATS) upper lobectomy in 2016. She developed a contralateral right lower lobe nodule and underwent a single-port right VATS wedge resection of the lower lobe nodule, subsequently confirmed as necrotising granulomatous inflammation with acid-fast bacilli, consistent with previous tuberculosis (TB) infection. On postoperative day 1, she had an episode of self-reverting ventricular tachycardia and bradycardia. Subsequent myocardial perfusion scan and coronary angiogram showed significant LV dysfunction and severe coronary artery disease with a left main stem (LMS) lesion. After agreement at MDT, an Endo-ACAB (endoscopic atraumatic coronary artery bypass grafting) was performed, via 3 ports, with the left internal mammary artery anastomosed to left anterior descending artery. She recovered well postoperatively and was discharged. Multiple sequential minimally invasive procedures are now routine and can be performed safely in patients with a complex combination of pathologies. In this case, bilateral single-port (anatomic and nonanatomic) lung resections were undertaken followed by coronary revascularisation with a total of 5 minimal access ports.

Abstract OT3-05-07: PATINA: A randomized open label phase III trial to evaluate the efficacy and safety of palbociclib + anti HER2 therapy + endocrine therapy vs anti HER2 therapy + endocrine therapy after induction treatment for hormone receptor positive, HER2 positive metastatic breast cancer

Background

Pre-clinical data and initial results from clinical studies point to the added benefit of CDK4/6 inhibition when combined with anti-HER2 tx. The current study is designed to evaluate the added benefit of palbociclib when given in combination with anti-HER2 and endocrine tx maintenance in the 1st†line setting of metastatic HER2+HR+ breast cancer.

Trial design

PATINA is an international, open-label, pivotal Phase III study. Primary objective is to demonstrate that the combination of palbociclib with anti-HER2 plus endocrine tx is superior to anti-HER2 plus endocrine tx in prolonging PFS. Sample size is 496 pts. The study starts after completion of 6-8 cycles of chemotherapy-containing anti-HER2 tx for metastatic breast cancer in the 1st line setting. Pts are eligible provided they are without evidence of disease progression by local assessment (i.e. CR, PR or SD). To account for the need for less intense tx regimens for a subset of pts diagnosed with HER2+ER+ disease, clinicians may recommend the combination of trastuzumab with either a taxane or vinorelbine prior to study initiation. Clinicians might also choose a non-pertuzumab option for pts previously treated with pertuzumab in the neo(adjuvant) setting. Secondary objectives include measures of tumor control (OR, CBR, DOR), OS, safety and QOL. The translational science main objective is to compare PFS estimates according to PIK3CA mutation status assessed by cfDNA analysis. Endocrine tx options are AI or fulvestrant. Premenopausal pts must receive ovarian suppression. The study has a 90% power to detect a hazard ratio of 0.667 in favor of the palbociclib arm. Pts approached to participate in AFT-38 will be asked to indicate on the informed consent forms whether remaining biospecimens and clinical data from the control arm of the study can be shared with the Mastering Breast Cancer (MBC) Initiative. The overarching purpose of the MBC is to create a mechanism for understanding the natural history of metastatic breast cancer by cataloguing longitudinally studied tumor-specific markers and treatment effects.

ClinicalTrials.gov Identifier: NCT02947685

Citation Format: Metzger-Filho O, Mandrekar S, Loibl S, Ciruelos E, Gianni L, Lim E, Miller K, Huang C, Koehler M, Francis P, Valagussa P, Goel S, Prat A, Goetz M, Loi S, Krop I, Carey L, Lanzillotti J, Winer E, Tripathy D, DeMichele A. PATINA: A randomized open label phase III trial to evaluate the efficacy and safety of palbociclib + anti HER2 therapy + endocrine therapy vs anti HER2 therapy + endocrine therapy after induction treatment for hormone receptor positive, HER2 positive metastatic breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr OT3-05-07.

Abstract P4-04-12: Therapeutic targeting of CDK4/6 inhibitor resistant breast cancer

Background:

Selective inhibitors of CDK4/6 kinases (CDK4/6i) were recently FDA approved for use in combination with endocrine therapy (ET), and represent the new standard of care. There are however patients who do not respond or develop resistance to these treatments, and therapies are required in this setting. While there is emerging data on the mechanisms of intrinsic insensitivity to CDK4/6i as monotherapies, which include cyclin E1 amplification, CDK6 amplification and Rb deletion, there is little data on mechanisms of resistance to combined ET and CDK4/6i.

Methods:

We established MCF7 cell line and patient-derived xenograft (PDX) models that are resistant to combined ET and Palbociclib (CDK4/6i) through long-term culture, allowing us to better understand mechanisms underlying CDK4/6i resistance and to model therapeutic strategies in this setting. We also evaluated our therapeutic strategy in vitro and in vivo using MCF cell lines that are resistant to ET, and in an ER+ PDX model derived from a patient who progressed on ET.

Results:

Cells resistant to CDK4/6i alone and in combination with ET show disrupted senescent pathways, and insensitivity to the induction of senescence. MDM2 inhibitors induce cells to enter into senescence, and consequently we are investigating the use of a new generation MDM2 inhibitor (CGM097, Novartis) either in combination with CDK4/6i treatment, or following acquisition of CDK4/6i resistance to prevent exit from senescence. We evaluated a CGM097 either in combination with CDK4/6i treatment, or in combination with fulvestrant following acquisition of CDK4/6i resistance to prevent exit from senescence. CGM097 was effective alone or in combination with fulvestrant in CDK4/6i resistant cells in vitro and in vivo, and resulted in a loss of G1 cells, and a reduction in B galactosidase, a senescence marker.

Another mechanisms of CDK4/6i resistance that has been identified is CDK2 activation, which can occur through Cyclin E amplification. As a second therapeutic strategy, we screened a panel of pan-CDK inhibitors with CDK2 activity in our resistant lines, and identified that CYC065 (Cyclacel), a highly selective CDK2/9 inhibitor, had the most durable response and highest synergy with ET in long-term culture. The combined resistant models were sensitive to CYC065 in vitro and in vivo. CYC065 was mechanistically distinct to CDK4/6i's as it caused arrest in a different phase of the cell cycle and affected expression of different cell cycle proteins.

Conclusion:

An underlying mechanism of combined ET and CDK4/6i resistance is senescent escape, which allows for normal proliferation upon removal of the drug. Using our in vitro and in vivo models of combined ET and CDK4/6i resistance, we have identified two novel therapeutic strategies for this disease, which represents the next clinical challenge in ER+ breast cancer as the natural history of disease is changed with the increasing use of CDK4/6i.

Citation Format: Lim E, Portman N, Alexandrou S, Haupt S, Haupt Y, Caldon E. Therapeutic targeting of CDK4/6 inhibitor resistant breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P4-04-12.

Different porcine reproductive and respiratory syndrome (PRRS) vaccine regimes and its effect on pig immunity status at Southeast Asia pig farms

Porcine reproductive and respiratory syndrome (PRRS) is a disease characterised by late-term reproductive failure in sows and gilts, and respiratory problems in piglets and growing pigs. In this study, 240 sera were collected from four farms that had been practicing different PRRS vaccination regime for more than a year and vaccinations were done at 2 months before sampling. Fifteen sera samples from four age groups: sows, growers, weaners and piglets were collected from each farm and analysed using IDEXX PRRS X3 ELISA for PRRSV antibodies. Pooled serum samples were tested by using nested-PCR that enable the differentiation of Type I and Type II PRRSV. Out of 80 pooled serum samples, none were positive for PRRSV indicating all age groups were not viraemic after vaccination. Results by ELISA test showed all the farms were seropositive for PRRS. ELISA testing showed no significant difference between the farms except for Farm B which practised whole herd US MLV vaccination. Farm B showed significantly lower (p<0.05) S/P ratio in their piglet, grower and sow groups which suggest there was low virus circulation in herd. Farm A which practised US MLV on sow was the only farm found to have seronegative status in their weaners. Data indicates PRRS MLV vaccination will not cause viraemia post four weeks vaccination and whole herd MLV vaccination may help to reduce virus circulation in PRRS endemic farm.

Factors related to suicidal behavior in korean patients with bipolar disorder: The effect of mixed features on suicidality

Introduction

The aim of the present study was to investigate various risk factors of suicidal behaviors, including the mixed features specifier, in Korean patients with bipolar disorder.

Methods

We retrospectively reviewed medical charts from 2005 to 2014. A total of 334 patients diagnosed with bipolar disorder using the DSM-IV TR were enrolled. Subjects were categorized into two groups according to their history of suicidal behavior and the demographic and clinical characteristics of the groups were compared, including the mixed features specifier. We re-evaluated the index episode using DSM-5 criteria and classified subjects into an index episode with mixed features group and an index episode without mixed features group. Logistic regression was performed to evaluate significant risk factors associated with suicidal behavior.

Results

Suicidal behavior had an independent relationship with mixed features at the index episode using DSM-5 criteria (OR = 3.39; 95% CI: 1.57–7.34) and number of previous depressive episodes (OR = 1.62; 95% CI: 1.34–1.95) in Korean bipolar patients. The mixed feature specifier was the strongest risk factor for suicidal behavior in the present study. Limitations: this was a retrospective study and structured psychiatric interviews were not conducted.

Conclusions

This study may help clinicians understand potential risk factors and manage bipolar disorders with suicidal behaviors. Clinicians should carefully monitor patients with bipolar disorder who exhibit numerous depressive episodes or mixed features for suicidal behavior.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Rediscovering the wound hematoma as a site of hemostasis during major arterial hemorrhage

BACKGROUND

Treatments for major internal bleeding after injury include permissive hypotension to decrease the rate of blood loss, intravenous infusion of plasma or clotting factors to improve clot formation, and rapid surgical hemostasis or arterial embolization to control bleeding vessels. Yet, little is known regarding major internal arterial hemostasis, or how these commonly used treatments might influence hemostasis.

OBJECTIVES

(i) To use a swine model of femoral artery bleeding to understand the perivascular hemostatic response to contained arterial hemorrhage. (ii) To directly confirm the association between hemodynamics and bleeding velocity. (iii) To observe the feasibility of delivering an activated clotting factor directly to internal sites of bleeding using a simplified angiographic approach.

METHODS

Ultrasound was used to measure bleeding velocity and in vivo clot formation by elastography in a swine model of contained femoral artery bleeding with fluid resuscitation. A swine model of internal pelvic and axillary artery hemorrhage was also used to demonstrate the feasibility of local delivery of an activated clotting factor.

RESULTS

In this model, clots formed slowly within the peri-wound hematoma, but eventually contained the bleeding. Central hemodynamics correlated positively with bleeding velocity. Infusion of recombinant human activated factor VII into the injured artery near the site of major internal hemorrhage in the pelvis and axillae was feasible.

CONCLUSIONS

We rediscovered that clot formation within the peri-wound hematoma is an integral component of hemostasis and a feasible target for the treatment of major internal bleeding using activated clotting factors delivered using a simplified angiographic approach.

CARD14 alterations in Tunisian patients with psoriasis and further characterization in European cohorts

BACKGROUND

Rare highly penetrant gain-of-function mutations in caspase recruitment domain family, member 14 (CARD14) can lead to psoriasis, a chronic inflammatory disease of the skin and other organs.

OBJECTIVES

To investigate the contribution of rare CARD14 variants to psoriasis in the Tunisian population and to expand knowledge of CARD14 variants in the European population.

METHODS

CARD14 coding exons were resequenced in patients with psoriasis and controls from Tunisia and Europe, including 16 European cases with generalized pustular psoriasis (GPP). Novel variants were evaluated for their effect on nuclear factor (NF)-κB signalling.

RESULTS

Rare variants in CARD14 were significantly enriched in Tunisian cases compared with controls. Three were collectively found in 5% of Tunisian cases, and all affected the N-terminal region of the protein harbouring its caspase recruitment domain or coiled-coil domain. These variants were c.349G>A (p.Gly117Ser), c.205C>T (p.Arg69Trp) and c.589G>A (p.Glu197Lys). c.589G>A (p.Glu197Lys) led to upregulation of NF-κB activity in a similar manner to that of previously described psoriasis-associated mutations. p.Arg69Trp led to sevenfold downregulation of NF-κB activity. One Tunisian case harboured a c.1356+5G>A splice alteration that is predicted to lead to loss of exon 9, which encodes part of the coiled-coil domain. No cases of GPP harboured an interleukin-36RN mutation, but one of 16 cases of GPP with a family history of psoriasis vulgaris harboured a c.1805C>T (p.Ser602Leu) mutation in CARD14.

CONCLUSIONS

These observations provide further insights into the genetic basis of psoriasis in the Tunisian population and provide functional information on novel CARD14 variants seen in cases from Tunisia and other populations.

IMP3 promotes stem-like properties in triple-negative breast cancer by regulating SLUG

IMP3 (insulin-like growth factor-2 mRNA binding protein 3) is an oncofetal protein whose expression is prognostic for poor outcome in several cancers. Although IMP3 is expressed preferentially in triple-negative breast cancer (TNBC), its function is poorly understood. We observed that IMP3 expression is significantly higher in tumor initiating than in non-tumor initiating breast cancer cells and we demonstrate that IMP3 contributes to self-renewal and tumor initiation, properties associated with cancer stem cells (CSCs). The mechanism by which IMP3 contributes to this phenotype involves its ability to induce the stem cell factor SOX2. IMP3 does not interact with SOX2 mRNA significantly or regulate SOX2 expression directly. We discovered that IMP3 binds avidly to SNAI2 (SLUG) mRNA and regulates its expression by binding to the 5' UTR. This finding is significant because SLUG has been implicated in breast CSCs and TNBC. Moreover, we show that SOX2 is a transcriptional target of SLUG. These data establish a novel mechanism of breast tumor initiation involving IMP3 and they provide a rationale for its association with aggressive disease and poor outcome.