Spatial and temporal epithelial ovarian cancer cell heterogeneity impacts Maraba virus oncolytic potential.

BACKGROUND: Epithelial ovarian cancer exhibits extensive interpatient and intratumoral heterogeneity, which can hinder successful treatment strategies. Herein, we investigated the efficacy of an emerging oncolytic, Maraba virus (MRBV), in an in vitro model of ovarian tumour heterogeneity. METHODS: Four ovarian high-grade serous cancer (HGSC) cell lines were isolated and established from a single patient at four points during disease progression. Limiting-dilution subcloning generated seven additional subclone lines to assess intratumoral heterogeneity. MRBV entry and oncolytic efficacy were assessed among all 11 cell lines. Low-density receptor (LDLR) expression, conditioned media treatments and co-cultures were performed to determine factors impacting MRBV oncolysis. RESULTS: Temporal and intratumoral heterogeneity identified two subpopulations of cells: one that was highly sensitive to MRBV, and another set which exhibited 1000-fold reduced susceptibility to MRBV-mediated oncolysis. We explored both intracellular and extracellular mechanisms influencing sensitivity to MRBV and identified that LDLR can partially mediate MRBV infection. LDLR expression, however, was not the singular determinant of sensitivity to MRBV among the HGSC cell lines and subclones. We verified that there were no apparent extracellular factors, such as type I interferon responses, contributing to MRBV resistance. However, direct cell-cell contact by co-culture of MRBV-resistant subclones with sensitive cells restored virus infection and oncolytic killing of mixed population. CONCLUSIONS: Our data is the first to demonstrate differential efficacy of an oncolytic virus in the context of both spatial and temporal heterogeneity of HGSC cells and to evaluate whether it will constitute a barrier to effective viral oncolytic therapy.

MD/PhD Training in Canada: Results from a national trainee and program director review.

PURPOSE: There has been limited examination of clinician scientist training in Canada, particularly regarding training integration and funding. This study assessed program structure, funding, tuition and mentorship structures available at Canadian MD/PhD programs. METHODS: Clinician Investigator Trainee Association of Canada administered an anonymous survey to current trainees and program directors that captured program structure, trainee funding, tuition and mentorship opportunities and needs across institutions. RESULTS: In June 2015, 101/228 (44%) trainees and 9/13 (69%) program directors completed the online survey. In all programs, students completed the PhD degree prior to clerkship training. Seven programs offered research training upon completion of pre-clerkship, four offered concurrent clinical and research training, and three offered alternative structures. Nine held seminars exposing students to clinical and research integration and two offered clinician scientist skills courses. Stipend funding and tuition varied, especially during clinical training years. Regarding mentorship, all programs held regular meetings, though eight programs do not have formal mentorship opportunities. Both trainees and program directors identified the need for further career planning and development support as a student priority. CONCLUSION: MD/PhD programs varied by program structure, funding, tuition and mentorship opportunities. Mechanisms to share and spread program innovations should be instated. Students may benefit from concurrent research and clinical training as well as courses specific to clinician scientist skill development. Decreasing debt burden may attract and retain trainees in this demanding path. To ensure mentorship programs align with trainee priorities, program directors should directly collaborate with students in their development and evaluation.

Myxoma virus-mediated oncolysis of ascites-derived human ovarian cancer cells and spheroids is impacted by differential AKT activity.

OBJECTIVE: We propose that metastatic epithelial ovarian cancer (EOC) is a potential therapeutic target for the oncolytic agent, Myxoma virus (MYXV). METHODS: Primary EOC cells were isolated from patient ascites and cultured as adherent cells or in suspension using Ultra Low-Attachment dishes. MYXV expressing green fluorescent protein was used to infect cells and spheroids. Infection was monitored by fluorescence microscopy, viral titering and immunoblotting for M-T7 and M130 virus protein expression, and cell viability by alamarBlue assay. Akti-1/2 (5 µM) and rapamycin (20 nM) were used to assay the role of PI3K-AKT signaling in mediating MYXV infection. RESULTS: Ascites-derived EOC cells grown in adherent culture are effectively killed by MYXV infection. EOC cells grown in suspension to form three-dimensional EOC spheroids readily permit MYXV entry into cells, yet are protected from the cytopathic effects of late MYXV infection. Upon reattachment (to model secondary metastasis), EOC spheroids are re-sensitized to MYXV-mediated oncolysis. The critical determinant that facilitates efficient MYXV infection is the presence of an activated PI3K-AKT signaling pathway. Treatment with the specific AKT inhibitor Akti-1/2 reduces infection of monolayer EOC cells and spheroids. Direct infection of freshly-collected ascites demonstrated that 54.5% of patient samples were sensitive to MYXV-mediated oncolytic cell killing. We also demonstrate that factor(s) present in ascites may negatively impact MYXV infection and oncolysis of EOC cells, which may be due to a down-regulation in endogenous AKT activity. CONCLUSIONS: Differential activity of AKT serves as the mechanistic basis for regulating MYXV-mediated oncolysis of EOC spheroids during key steps of the metastatic program. In addition, we provide the first evidence that MYXV oncolytic therapy may be efficacious for a significant proportion of ovarian cancer patients with metastatic disease.

A Case of Brevibacillus brevis Meningitis and Bacteremia.

Brevibacillus species are environmental organisms that are rarely implicated as human pathogens. We present the case of postsurgical Brevibacillus brevis bacterial meningitis and an associated bacteremia after debulking surgery for a newly diagnosed pilocytic astrocytoma in a 19-year-old woman. The patient experienced clinical cure with a 4-week course of vancomycin, but her postinfectious course was complicated by the development of a pseudomeningocele that required surgical repair. To our knowledge, this is the first described case of a central nervous system infection caused by Brevibacillus brevis in the literature.

The Integration of Clinical and Research Training: How and Why MD-PhD Programs Work.

For over 60 years, MD-PhD programs have provided integrated clinical and research training to produce graduates primed for physician-scientist careers. Yet the nature of this integrated training is poorly characterized, with no program theory of MD-PhD training to guide program development or evaluation. The authors address this gap by proposing a program theory of integrated MD-PhD training applying constructs from cognitive psychology and medical education. The authors argue that integrated physician-scientist training requires development of at least three elements in trainees: cognitive synergy, sense of self, and professional capacity. First, integrated programs need to foster the cognitive ability to synergize and transfer knowledge between the clinical and research realms. Second, integrated programs need to facilitate development of a unique and emergent identity as a physician-scientist that is more than the sum of the individual roles of physician and scientist. Third, integrated programs should develop core competencies unique to physician-scientists in addition to those required of each independently. The authors describe how programs can promote development of these elements in trainees, summarized in a logic model. Activities and process measures are provided to assist institutions in enhancing integration. Specifically, programs can enact the proposed theory by providing tailored MD-PhD curricula, personal development planning, and a supportive community of practice. It is high time to establish a theory behind integrated MD-PhD training as the basis for designing interventions and evaluations to develop the foundations of physician-scientist expertise.

Tumor Board Shadowing: A Unique Approach for Integrating Radiation Oncologists Into General Medical Student Education.

PURPOSE: Radiation oncology is often overlooked in US medical school curricula, with few opportunities for most students to learn about the specialty or the value of radiation therapy in cancer care. Tumor boards represent a potential avenue not only to increase students' exposure to radiation oncologists but also to provide a fundamental understanding of the multidisciplinary nature of cancer care and effective collaboration in clinical practice. METHODS AND MATERIALS: In this study, we evaluated a novel radiation oncologist-driven tumor board shadowing experience at 3 medical schools in the United States and Canada. A total of 323 first- and second-year medical students participated, of whom 77.4% completed a follow-up survey assessing the effectiveness of the program as a learning tool. RESULTS: Compared with traditional clinical shadowing, students were more likely to believe that tumor board shadowing provided a similar or better experience in terms of educational content (85%), exposure to a new field (96%), and overall experience (89%). Forty-eight percent of students perceived a greater amount of multidisciplinary collaboration in oncologic care than they thought existed prior to attending. Forty-eight percent of students also felt more competent interacting with oncologists after participating, whereas 21% felt more competent interacting with patients with cancer. Students' perception of increased competence was correlated with the amount of time their assigned physician mentor spent answering their questions after the tumor board (P < .01). Second-year medical students also had a more favorable overall experience than first-year medical students did (P = .04). CONCLUSIONS: Multidisciplinary tumor boards can be used effectively as a unique immersive learning opportunity that can be feasibly implemented to improve knowledge of clinical oncology and multidisciplinary care in medical schools and expose students to physicians in smaller fields such as radiation oncology.

MicroRNAs in the human pituitary.

MicroRNAs (miRNAs) represent a novel class of small RNA molecules that play a crucial role as post-transcriptional regulators of gene expression. As evidence for the involvement of miRNAs in various cellular processes increases, it is important to examine how miRNAs regulate gene expression. In the pituitary, aberrant miRNA expression is strongly linked with neoplasia, thus suggesting they play a role in the control of cell proliferation in adenomas. Research has built fundamental connections between aberrant miRNA expression and clinicopathological features of pituitary adenomas. Moreover, deregulated expression of miRNA target genes is often implicated in important biological pathways and thus provides significant insight into the role of miRNAs in tumorigenesis. This review will assess the significance of miRNAs in pituitary pathology.