The role of the anorectic neuropeptide CART in breast cancer

MCT Research Talks – 16th January 2017

Breast cancer currently affects 1 in 8 women in Ireland, with over 3000 reported cases each year. The most common subtype of breast cancer, known as Estrogen Receptor positive (ER+) breast cancer, accounts for roughly 70% of all breast cancers diagnosed. The most common drug used to treat this disease (Tamoxifen) works by preventing estrogen from driving the growth of the cancer cells, however, roughly 1 in 3 women will be resistant to tamoxifen treatment, highlighting the need for further research into this field. A number of years ago, though mining of publically available datasets, we identified a gene known as CART to be a marker of poor prognosis in ER+ breast cancer. CART (The Cocaine- and Amphetamine-Regulated Transcript) is a neuropeptide involved in processes such as feeding and drug reward. We have identified that high expression of CART in breast cancer patients correlates with poor overall survival, and also a poor response to tamoxifen. We also demonstrated that CART could influence the activity of ERα in a ligand-independent manner [1]. Our current research focuses on combining proteomic (mass-spectrometry) and transcriptomic (RNA-seq) approaches in order to fully understand the role CART plays in ER+ breast cancer. We aim to modulate the expression of these identified targets in order to investigate whether any of these targets could slow the growth of breast cancer cells in vitro. Combining these approaches, we hope to identify novel therapeutic opportunities for patients with ER+ breast cancer.

Recommended reading:

[1] DJ Brennan, DP O’Connor et al., The Cocaine- and Amphetamine-Regulated Transcript mediates ligand-independent activation of ERα, and is an independent prognostic factor in node-negative breast cancer. Oncogene 2012, 31, 3483–3494; doi:10.1038/onc.2011.519

Brian Mooney, Darran O’Connor

MCT student, Lisa Dwane, talks about her research and recent achievements

cropped-RCSI-logo-1.jpgFollowing completion of my Pharmacology degree in UCD, I began a PhD in breast cancer research under the supervision of Dr. Darran O’Connor, a career I have always been very determined to follow. My research is focused on endocrine-driven breast cancer and understanding the molecular mechanisms that drive this subtype of cancer. Currently, half of breast cancer patients that receive anti-endocrine therapies will relapse, so there is an urgent need for the identification of novel therapeutic targets. Our research is focused on the deubiquitinating enzyme USP11, which we believe plays a key role in driving endocrine-driven breast cancer. When we silence USP11 in vitro, we see a reduction in estrogen receptor activity and cell viability. During the final year of my PhD, I hope to elucidate the mechanism by which USP11 plays this role, and determine the prognostic relevance of USP11 in breast cancer. This could potentially lead to a better understanding of endocrine-driven breast cancer and with further validation, USP11 may represent a novel therapeutic target.

Lisa Dwane presents her research at the Irish Cancer Society’s Researcher of the Year Award. december, 1st, 2016. TCD
Lisa Dwane presents her research at the Irish Cancer Society’s Researcher of the Year Award. December, 1st, 2016. TCD

As a pharmacologist, I was thrilled to win best oral presentation at the Irish Association of Pharmacologists Annual Meeting! The standard of talks throughout the day were excellent, with a wide range of topics explored. I was also a finalist for the Irish Cancer Society’s Researcher of the Year Award, which took place 1st December at Trinity College Dublin. The purpose of the evening was to communicate our research to a lay audience, which proved more difficult than expected! Although I didn’t take home the award it was a very enjoyable evening, and the experience was invaluable. As scientists it is important for us to share and communicate our research with the general public and this was a skill I gained from the night!

Winners and finalists for the Irish Cancer Society’s Researcher of the Year Award
Winners and finalists for the Irish Cancer Society’s Researcher of the Year Award

Targeting drug resistance in neuroblastoma

MCT Research Talks 5th December 2016  rcsi-logo

Cancer Genetics Group

Neuroblastoma is a childhood cancer caused by the abnormal growth and development of neural crest cells (1). The disease commonly affects children age 5 years or younger. Approximately 50% of children have cancer cells that have migrated to distant sites in the body and formed tumour masses at the time of diagnosis. The main challenge in treating neuroblastoma is to combat tumour metastasis and development of resistance to multiple chemotherapeutic drugs. Despite major advances in available therapies, children with drug resistant and/or recurrent neuroblastoma have a dismal outlook with 5 year survival rates of less than 20%.

Research of Prof. Stallings lab is focused on elucidating the molecular events that contribute to the development and progression of neuroblastoma (2).  A major area of research involves the identification and functional analysis of microRNAs that contribute to chemotherapy resistance in neuroblastoma, along with the development of microRNA-mediated therapeutics.

The main research projects were presented at the Departmental meeting on December, 5th.

Microscopic examination of drug resistant neuroblastoma cells KellyCis83. Cells look healthy and can be kept for another 2-3 days to form a more dense population.
Microscopic examination of drug resistant neuroblastoma cells KellyCis83. Cells look healthy and can be kept for another 2-3 days to form a more dense population.

The first talk by Olga Piskareva has explored how current concepts of development of drug resistant, tumour microenvironment and cell-to-cell communication can be applied to reconstruct relapsed or drug resistant neuroblastoma microenvironment using 3D tumour models.

TEM analysis of exosome fractions. Vesicle sizes range from 30 to 200nm in Kellycis83 (A) and Kelly (B) neuroblastoma cells. (C) EVs which appear larger than the 100 nm upper limit for exosomes (D) Close up of the dried exosome preps identify the typical bowl shaped morphology associated with TEM images of exosomes. (3)
TEM analysis of exosome (EV) fractions. Vesicle sizes range from 30 to 200nm in Kellycis83 (A) and Kelly (B) neuroblastoma cells. (C) EVs which appear larger than the 100 nm upper limit for exosomes (D) Close up of the dried exosome preps identify the typical bowl shaped morphology associated with TEM images of exosomes (3).

The second talk was presented by Ciara Fallon. Ciara is our StAR PhD student. She has selected the project ‘Exosome mediated drug resistance in high-risk neuroblastoma’ as her first choice.  At the moment she is doing her lab placement in Cancer Genetics group as a part of the RCSI StAR PhD Programme. Built upon results of the former BioAt PhD Student Ross Conlon (3), Ciara’s project is focused on the validation of exosomal miR-548d-5p as a regulator of cell viability and proliferation in cisplatin sensitive and resistant neuroblastoma cell lines.

Finally, the last, but not least was a talk by John Nolan. His talk entitled “MiRNA-124-3p Reduces Cell Viability in Cisplatin Resistant Neuroblastoma Cell Models” was focused on the results submitted to the Royal College of Surgeons for the Degree of Doctor of Philosophy. His studies cover the development of cross resistance to other drugs, investigation of common altered proteins and signaling pathways in cisplatin resistant neuroblastoma cell lines and validation of miRNA that can target these proteins and stop cell proliferation. Part of the results was published last year in Cancer Letters (4).

The work carried out in Prof. Stallings lab is supported through the research grant to Prof. Ray Stallings and PhD fellowship to John Nolan by National Children’s Research Centre, Crumlin Hospital. ncrc

References:

  1. Davidoff, A. M. Neuroblastoma. 2012 Semin. Pediatr. Surg. 21, 2–14.
  2. Piskareva, O., Stallings, R. Neuroblastoma. In: Epigenetic Cancer Therapy edited by Grey S., Elsevier 2015.
  3. Conlon, R., Analysis of microRNA bearing exosomes in models of drug resistant neuroblastoma. PhD Thesis. Dublin: Royal College of Surgeons in Ireland; 2015.
  4. Piskareva, O., Harvey, H., Nolan, J., Conlon, R., Alcock. L., Buckley, P., Dowling, P., O’Sullivan, F., Bray, I., Stallings, T.L. The development of cisplatin resistance in neuroblastoma is accompanied by epithelial to mesenchymal transition in vitro. 2015 Cancer Letters, 364:142-55.

Reported by Olga Piskareva