Abstract P3-03-07: High-throughput pharmacogenomic platform to functionally probe breast cancer vulnerabilities in the context of the 3-dimensional tumor microenvironment

The pharmacological vulnerabilities of malignant cells have been traditionally evaluated by the use of cell lines grown in vitro in 2-dimensional (2D) plastic surfaces. In contrast, malignant tumors in vivo grow as 3-dimensional (3D) cellular masses. We used Estrogen Receptor (ER)-positive (MCF7, ZR75-1 and T47D) and triple-negative (MDA-MB-231) breast cancer (BrCa) cells to assess the differences between the malignant growth in 2D vs. 3D conditions with regards to morphology, molecular characteristics and response to therapeutic agents. The ER-positive BrCa cells formed compact spheroids when grown in collagen type I or matrigel; in contrast the MDA-MB-231 cells assumed an invasive phenotype characterized by infiltrating bundles of cells. Antiestrogens induced acinar differentiation in the compact spheroid morphology of ER-positive BrCa cells. This effect of antiestrogens was blocked in co-cultures of BrCa cells with bone marrow stromal cells, suggesting that the 3-dimensional microenvironment of distant metastatic sites can affect the susceptibility of BrCa cells to anti-tumor agents. We further probed this question through pharmacological screens of ~100 FDA-approved antineoplastic agents and 400 target-annotated kinase inhibitors, to assess the pathophysiological relevance of these in vitro interactions and to identify specific BrCa vulnerabilities in 3D conditions. The 3D spheroid morphology was associated with significant decrease in the efficacy of several classes of conventional DNA-damaging (e.g. anthracyclins) and anti-microtubule (e.g. vinca alkaloids) agents, proteasome inhibitors, as well as recently established targeted therapies, includding kinase inhibitors. This differential 3D spheroid-associated drug resistance vs. sensitization was more pronounced for the triple-negative MDA-MB-231 cell line compared to the ER-positive BrCa cells. Interestingly, inhibition of folate metabolism induced reduced viability of ER-positive BrCa spheroids, indicating increased dependency of ER-positive tumor cells on this pathway, under 3D growth conditions. Interestingly, mut-p53 T47D 3D spheroids were resistant to antifolates, suggesting a possible role of functional p53 for the anti-BrCa effect of antifolates in 3D conditions. Gene expression analysis and reverse-phase protein array analyses of BrCa cells in this system indicated that growth of malignant cells as 3D spheroids was associated with switch to glycolysis metabolism and up-regulation of survival signals (e.g. Mcl1, Hsp70 et.c.). We conducted a genome-wide CRISPR screen in MCF7 and MDAMB231 2D cultures and identified several known and previously underappreciated BrCa essential genes; we are currently using the insight obtained by these molecular analysis to conduct focused CRISPR screens in our 3D cultures, to validate the genetic vulnerabilities observed in 2D conditions and to determine the mediators of malignant growth and drug resistance in 3D conditions. This approach can reveal novel and previously underappreciated therapeutic targets for drug-resistant BrCa.

Citation Format: Dhimolea E, De Matos Simoes R, Awate P, Tang H, Culhane A, Mitsiades C. High-throughput pharmacogenomic platform to functionally probe breast cancer vulnerabilities in the context of the 3-dimensional tumor microenvironment [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-03-07.

Abstract P5-06-04: Distinct BRCA1 and BRCA2 specific functions at stalled replication forks - Clinical implications for differences between BRCA1 and BRCA2 mutation driven cancer

This abstract was withdrawn by the authors.

Abstract OT2-02-03: Pilot study of zirconium-89 bevacizumab positron emission tomography for imaging angiogenesis in patients with inflammatory breast carcinoma receiving preoperative chemotherapy

Background: Inflammatory breast cancer (IBC) continues to have a poor prognosis despite standard tri-modality treatment with chemotherapy, mastectomy and radiation. Current methods of assessing primary tumor response (i.e., clinical exam and breast magnetic resonance imaging [MRI]) are limited for distinguishing residual tumor from responsive disease because of persistent morphologic changes in the breast. Therefore, the inability to accurately assess tumor response during treatment often results in the continuation of ineffective systemic chemotherapy until definitive pathologic evaluation at mastectomy. IBC has a highly angiogenic phenotype which is believed to play a role in this tumor's aggressiveness. The novel radiotracer Zirconium-89 (89Zr)-bevacizumab was developed for imaging tumor angiogenesis with PET. We hypothesize that, as an imaging biomarker of angiogenesis, 89Zr-bevacizumab-PET/CT is a more specific noninvasive functional imaging modality for detecting the presence of tumor angiogenesis compared to current diagnostic methods and will serve as a predictor of response to therapy in patients (pts) with IBC.

Methods: Pts with newly diagnosed HER2neg IBC who will receive preoperative chemotherapy are eligible for this pilot study. 89Zr-bevacizumab-PET/CT, breast MRI and FDG-PET/CT are performed before, after 2 cycles, and at the completion of preoperative therapy. Biopsies of primary IBC tumors are obtained prior to and after 2 cycles of preoperative therapy. At the completion of preoperative therapy, pts proceed to mastectomy or biopsy if ineligible to proceed to mastectomy based on current standards for assessing primary tumor response, i.e., clinical exam, breast MRI and lack of systemic progression. At the time of mastectomy, standard evaluation of the surgical specimen will determine pathologic response of IBC to preoperative chemotherapy. A research sample will be collected if residual cancer is present at the time of mastectomy for histologic evaluation of tumor angiogenesis.

Objectives/Correlatives: The primary objective is to determine feasibility of 89Zr-bevacizumab-PET/CT imaging in pts with IBC. The primary endpoint is assessment of radiolabeling of chelated bevacizumab and number of successfully acquired 89Zr-bevacizumab-PET/CT scans. Correlative studies will be performed on IBC tissue to assess extent of angiogenesis including microvessel density, vessel diameter, vascular pericyte coverage and tumor VEGF levels. Secondary objectives are: 1) To determine if 89Zr-bevacizumab accumulation in primary IBC tumors correlates with the extent of angiogenesis determined by correlative analysis on IBC tissue; 2) To assess the predictive value of 89Zr-bevacizumab-PET/CT after 2 cycles and at the end of preoperative therapy for determining pathologic response at mastectomy as given by residual cancer burden.

Statistics: This is an accrual, not statistical based, feasibility justification. Planned sample size is 10 in order to make a preliminary statement about feasibility and ability for 89Zr-bevacizumab-PET/CT to serve as a surrogate in vivo biomarker of tumor angiogenesis and response to preoperative chemotherapy.

Clinical Trial Information: NCT01894451.

Citation Format: Jacene HA, Overmoyer B, Schlosnagle EJ, Abbott A, Yeh E, Paolino J, Goel S, Culhane A, Bellon JR, Nakhlis F, Hirshfield-Bartek J, Van den Abbeele A. Pilot study of zirconium-89 bevacizumab positron emission tomography for imaging angiogenesis in patients with inflammatory breast carcinoma receiving preoperative chemotherapy [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr OT2-02-03.

Towards vertical integration in general practice education: literature review and discussion paper

BACKGROUND

Medical education policy in Ireland has enabled an increase in undergraduate and postgraduate education activity in general practice. Internationally, 'vertical integration in general practice education' is suggested as a key strategy to support the implementation of this policy development.

AIMS

To review the emerging literature on vertical integration in GP education, specifically to define the concept of 'vertical integration' with regard to education in general practice and to describe its benefits and challenges.

METHODS

We searched 'Pubmed', 'Academic Search Complete', 'Google', and 'MEDLINE' databases using multiple terms related to 'vertical integration' and 'general practice education' for relevant articles published since 2001. Discussion papers, reports, policy documents and position statements were identified from reference lists and retrieved through internet searches.

RESULTS

The key components of 'vertical integration' in GP education include continuous educational pathway, all stages in GP education, supporting the continuing educational/professional development needs of learners at each stage and effective curriculum planning and delivery. Many benefits (for GPs, learners and the community) and many challenges (for GPs/practices, learners and GPs in training) have been described. Characteristics of successful implementation include role sharing and collaborative organisational structures.

CONCLUSIONS

Recent developments in medical education in Ireland, such as the increase in medical school clinical placements in general practice and postgraduate GP training and the introduction of new competence assurance requirements offer an important opportunity to further inform how vertical integration can support increased educational activity in general practice. Describing this model, recognising its benefits and challenges and supporting its implementation in practice are priorities for medical education in Ireland.

Helicobacter Pylori eradication therapy: getting research into practice

Helicobacter Pylori (H. Pylori) is the primary cause of duodenal ulcer (DU). Guidelines recommend that all patients with DU be considered for Helicobacter Pylori Eradication Therapy (HPET). However, the proportion of patients with DU on long term anti-ulcer medication receiving HPET is small. This study examined the effectiveness of the continuing medical education (CME) network of the Irish College of General Practitioners (ICGP) in promoting best practice in DU treatment among GPs in an eastern region of Ireland. Ninty eight GPs recruited from the CME network of the ICGP were randomised in two cohorts. Cohort 1 received an (early) intervention; GPs were asked to identify their patients with DU receiving long term anti-ulcer medication and prescribe HPET according to defined criteria. Cohort 2 received the intervention later. Prescribing of HPET was monitored using routine prescribing data. Twenty per cent (286/1,422) of patients in cohort 1 and 19.2% (127/661) in cohort 2 had a DU. After exclusions, 53% (152/286) in cohort 1 and 30.7% (39/127) in cohort 2, were eligible for HPET. A significantly higher proportion of patients in cohort 1 received HPET compared with cohort 2 during the early intervention period (13.8% vs 0.0%, p<0.05). Reasons for not prescribing HPET included concurrent illness in patients, failure to comply with treatment. Best practice guidelines on HPET treatment of DU can be successfully applied using CME networks. This model could be repeated in another therapeutic area where established research is not yet current practice.

Guidelines for the management of Helicobacter pylori-related upper gastrointestinal diseases. Irish Helicobacter Pylori Study Group

The discovery of H. pylori is the most important development in gastroduodenal disease this century. It has completely changed our understanding of conditions that occur in the upper gastrointestinal tract. Eradication of the bacterium will cure peptic ulcer disease, decrease the symptoms of non-ulcer dyspepsia and may prevent gastric cancer. There has been an exponential increase in the amount of research in this area in recent years and, consequently, there is considerable confusion as to how H. pylori-related conditions should be managed. It is hoped that these guidelines will clarify some of these issues.

The contribution of the undergraduate rural attachment to the learning of basic practical and emergency procedural skills

OBJECTIVE

To assess the effect of a four-week rural attachment on the knowledge and competency of medical students in basic practical and emergency procedures.

DESIGN

A before and after comparison of self-reported level of competence in 72 basic, emergency, diagnostic and therapeutic procedural skills.

PARTICIPANTS

Eighty-five final year medical students at the University of Western Australia in 1991.

OUTCOME MEASURE

A student was considered competent if he or she claimed to be able to do a procedure either alone or with assistance.

RESULTS

Over 50% of students were competent in 57 procedures after the attachment compared with 37 procedures before it. There were 26 procedures in which more than 20% of students increased their competence.

CONCLUSION

A higher priority needs to be paid to the undergraduate teaching of procedural skills. Rural attachments can play an important part in training medical students in the practical skills required of interns.