Epigenetic Mechanisms in Breast Cancer (Luca Magnani)

In this episode of the Epigenetics Podcast, we talked with Luca Magnani from Institute of Cancer Research and UNIMI in Milan about his work on epigenetic mechanisms of drug resistance and cancer cell dormancy in breast cancer.

We start the interview by putting our focus on his significant contributions to the understanding of estrogen receptor-positive breast cancer. In a foundational study from 2013, Professor Magnani and his colleagues illuminated the role of genome-wide reprogramming of the chromatin landscape in conferring resistance to endocrine therapy. This research marked a departure from a purely genetic mutation paradigm, proposing instead that epigenetic modifications play a pivotal role in the development of drug resistance.

A fascinating part of our conversation centers on the role of pioneer transcription factors, particularly PBX1, in regulating the estrogen receptor's transcriptional response. Professor Magnani explains how PBX1, typically associated with hematopoietic development, influences estrogen receptor activity, thereby shaping the cancer cell's fate and response to treatment.

Continuing our exploration, we discuss the critical distinctions between primary and metastatic breast cancer through the lens of epigenetic reprogramming. By analyzing samples from women with breast cancer, Professor Magnani's work identifies specific enhancer usage that marks the transition to a drug-resistant state which was a breakthrough in linking epigenetic alterations to real-world patient outcomes. He emphasizes that the reliance on genetic mutations alone does not adequately explain the mechanisms of drug resistance, pushing the field to consider the epigenetic landscape more deeply.

Our conversation also touches on the evolution of experimental techniques. Professor Magnani shares insights into the transition from traditional ChIP-seq methods to CUT&RUN, demonstrating the need for techniques that cater to the limited material available from clinical samples. This adaptability mirrors the dynamic nature of cancer itself, as cells continuously evolve under therapeutic pressure.

As we traverse through the complexities of dormancy and reactivation in cancer cells, Professor Magnani enlightens us on the unpredictable nature of tumor behavior. He describes how cancer cells can enter dormant states and how their awakening is influenced by environmental factors, akin to an evolutionary response to stressors, thus revealing the intricate balance between survival and proliferation.

In the latter part of the episode, we explore Professor Magnani's vision for the future of breast cancer research, which includes the need for better animal models that mimic human disease. His pursuit of understanding estrogen receptor behavior both in healthy and cancerous cells reflects a holistic approach to cancer biology, aiming to decipher the transition from normal tissue to malignancy.

References

• Magnani, L., Stoeck, A., Zhang, X., Lánczky, A., Mirabella, A. C., Wang, T. L., Gyorffy, B., & Lupien, M. (2013). Genome-wide reprogramming of the chromatin landscape underlies endocrine therapy resistance in breast cancer. Proceedings of the National Academy of Sciences of the United States of America, 110(16), E1490–E1499. https://doi.org/10.1073/pnas.1219992110

• Nguyen, V. T., Barozzi, I., Faronato, M., Lombardo, Y., Steel, J. H., Patel, N., Darbre, P., Castellano, L., Győrffy, B., Woodley, L., Meira, A., Patten, D. K., Vircillo, V., Periyasamy, M., Ali, S., Frige, G., Minucci, S., Coombes, R. C., & Magnani, L. (2015). Differential epigenetic reprogramming in response to specific endocrine therapies promotes cholesterol biosynthesis and cellular invasion. Nature communications, 6, 10044. https://doi.org/10.1038/ncomms10044

• Patten, D. K., Corleone, G., & Magnani, L. (2018). Chromatin Immunoprecipitation and High-Throughput Sequencing (ChIP-Seq): Tips and Tricks Regarding the Laboratory Protocol and Initial Downstream Data Analysis. Methods in molecular biology (Clifton, N.J.), 1767, 271–288. https://doi.org/10.1007/978-1-4939-7774-1_15

Related Episodes

• Enhancers and Chromatin Remodeling in Mammary Gland Development (Camila dos Santos)

• Contribution of Estrogen Receptor to Breast Cancer Progression (Jason Carroll)

• Circulating Epigenetic Biomarkers in Cancer (Charlotte Proudhon)

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