Kristopher Sarosiek

Assistant Professor of Radiation Biology

Department of Environmental Health

Staff Portraits 12.2015. Kristopher Sarosiek, Ph.D.Sarosiek Laboratory Research Interests:

We seek to understand how the regulation of apoptosis (programmed cell death) in healthy as well as diseased cells affects their sensitivity to damage or stress, including genotoxic damage induced by radiation or chemotherapy. We plan to leverage this knowledge to improve patient care by predicting and preventing healthy tissue toxicity from environmental, medical and pathological factors. Our research utilizes in vitro and in vivo models of cancer and neurodegenerative diseases as well as biochemical, cellular and molecular biology techniques to identify critical factors regulating apoptosis and how they may be targeted therapeutically.

Please take a moment to read about current projects in the laboratory.

The Sarosiek Laboratory studies apoptosis, which is controlled by the BCL-2 family of proteins at the mitochondria. In this simplified schematic, cellular stress or damage signals [1] unleash pro-death proteins (BH3-only “activators” of apoptosis) [2], which can either be bound and sequestered by anti-apoptotic proteins such as BCL-2, BCL-XL or MCL-1 [3] or activate BAX and/or BAK [4]. Activated BAX or BAK form pores in mitochondrial membranes, leading to release of cytochrome c and consequent activation of caspases [5] for dismantling of the cell. In the average adult, between 50 and 70 billion cells die each day via apoptosis to maintain homeostasis. Defects in this pathway are associated with cancer as well as neurodegenerative, inflammatory and autoimmune diseases.

Join our team!

Postdoctoral Fellows: The laboratory is currently recruiting smart, ambitious and hard-working postdocs that want to change the world. If you are interested in joining the team, please send an email to and include the following materials:

1. A current CV
2. Contact information for 3 references
3. A cover letter describing your past research experience and future research goals

Graduate Students: Students currently enrolled in any of Harvard’s graduate programs are eligible to join the Sarosiek Laboratory. Please email your CV and a brief description of your research interests to in order to schedule an in-person interview.

About Dr. Sarosiek:

Kris pursued graduate training in Molecular and Cellular Pharmacology at the University of Miami School of Medicine under the mentorship of Izidore Lossos, MD.  After receiving his PhD, Kris joined the laboratory of Anthony Letai, MD, PhD, at the Dana-Farber Cancer Institute/ Harvard Medical School for his postdoctoral fellowship.

In collaboration with others in the Letai laboratory, Kris found that some cancer cells are more primed to undergo programmed cell death (apoptosis) than others, as measured by a novel assay called BH3 Profiling (Ni Chonghaile & Sarosiek, et al., Science, 2011). Cancer cells and patient tumors that are more primed to undergo apoptosis are consequently more sensitive to chemotherapy treatment. This finding potentially explains why some patients respond favorably to chemotherapy while others do not. Kris has also utilized BH3 profiling to identify novel interaction preferences among the BCL-2 family of proteins, finding that BID preferentially activates BAK while BIM preferentially activates BAX to trigger apoptosis (Sarosiek, et al., Molecular Cell, 2013)

More recently, Kris has characterized how apoptosis is regulated in healthy tissues and how this impacts cell fate decisions in response to damage and stress (Sarosiek, et al., Cancer Cell, 2016). He has also worked to identify the key molecular determinants of priming within cancer cells, focusing on events during the process of transformation.

In 2016, Kris started his laboratory at the Harvard School of Public Health in Boston. The long-term goal of his laboratory is to develop a better understanding of how cell death is regulated in healthy and diseased cells in order to expose novel opportunities for therapeutic intervention.

Contact information:

Kristopher Sarosiek, Ph.D.
Assistant Professor of Radiation Biology
John B. Little Center for Radiation Sciences
Department of Environmental Health
Harvard T.H. Chan School of Public Health
220 Longwood Avenue
Goldenson 553
Boston, MA 02115
Office: (617) 432-1104

To view a complete list of our publications, please visit Publications or Google Scholar.

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