In cells, DNA wraps around a protein complex consisting of proteins called histones. Chemical modifications to histones can affect gene expression, which is key to activating or suppressing cancer progression. Histone monoaminylation, in which an amine (e.g., serotonin, dopamine, or histamine) attaches itself to a histone, is a newfound type of epigenetic modification whose role remains elusive in these processes. Dr. Zhang is using chemical biology tools to study the functions of these modifications as well as their effects on other adjacent, pre-existing cancer-associated modifications. This research may establish a foundation for how this epigenetic modification regulates gene expression and offer insight into the role of amines in the progression of cancer and human neurodegenerative disorders. Dr. Zhang received his PhD from the California Institute of Technology, Pasadena and his BS from Tsinghua University, Beijing.

Dr. Zhang is developing small molecules that promote targeted protein degradation in human cancers. Conventional small molecule anticancer drugs act by directly inhibiting the functions of proteins. Although targeted cancer therapies have been successful in recent years, many oncogenic proteins are still considered “undruggable” because the conventional drug design strategy fails to interfere with these proteins. One way to target “undruggable” oncogenic proteins may be to create a new type of small molecule that delivers these proteins to the cellular degradation system, thereby promoting their destruction. By integrating chemical tools, proteomic platforms, and molecular biology approaches, Dr. Zhang aims to develop protein degraders as a new drug modality to expand treatment opportunities in human cancer.

Cancer growth is often driven by the dysregulation of a class of proteins known as small GTPases. These proteins act as molecular "on/off" switches that regulate critical cellular processes such as cell division and movement. However, in cancer, these molecular switches often become stuck in the "on" state due to mutations that hamper GTP hydrolysis, the reaction that turns "off" the GTPase switch. One notable example is the family of GTPases encoded by Ras genes, which are mutated in 30% of all human cancers. Dr. Zhang's research aims to design small molecules that inactivate these mutant GTPases by accelerating GTP hydrolysis. His research will provide a new therapeutic mechanism for the treatment of mutant Ras-driven cancer for which no direct therapies are yet available. The design principles may also apply to the modulation of other small GTPases whose overactivation underlies cancer progression.

On the cellular level, aging manifests as cellular senescence—when cells permanently stop multiplying but do not die. Aberrant accumulation of senescent cells is thought to be a major contributor to age-dependent tissue degeneration and its associated pathologies. Elimination of senescent cells has been shown to improve age-associated tissue damage pathologies and extend healthy lifespan in mice. Senescent cells undergo extensive remodeling on their surface, including increased production of many surface proteins. Dr. Zhang [HHMI Fellow] is using a quantitative proteomics approach to investigate the mechanisms and biological consequences of cell surface remodeling in senescent cells. His goal is to identify new therapeutic targets on the senescent cell surface and develop next-generation chimeric antigen receptor (CAR) T cells and antibodies to evaluate their impact on age-related diseases. Success with this approach may have a transformative impact on treating life-threatening diseases like cancer, fibrosis, and atherosclerosis. Dr. Zhang received his PhD from Gerstner Sloan Kettering Graduate School and his BS from Sun Yat-Sen University.

Antibodies, vaccines, checkpoint inhibitors, and CAR-T cells have all been successful in leveraging the immune system against disease, but these treatment strategies still have limitations. Dr. Zhou is designing new macromolecules to direct the immune response to cancer. She plans to engineer dynamic, functional proteins that respond to specific protein post-translational modifications, conformations, or complexes. She hypothesizes that these conditionally activated proteins will be able to recognize cancer-specific antigens, drive protein-protein or protein-substrate interactions, or help build synthetic cell signaling pathways, and therefore can be harnessed to enact specific anti-tumor responses.

Our immune system can help us prevent or slow cancer development. Human CD4⁺ T cells play critical roles in regulating our immune responses to fight cancer. Upon encountering a pathogen, naïve CD4⁺ T cells differentiate into different T helper (Th) cells to perform diverse immune-modulatory functions. Variability in this differentiation process is associated with variable responses to cancer immunotherapy. While several genes necessary for differentiation have been identified, researchers lack a comprehensive map and a predictive model of the larger gene regulatory network (GRN) controlling this process. Dr. Zhu [Connie and Bob Lurie Fellow] plans to combine functional genomics with mathematical modeling to systematically map and model the human CD4+ T cell differentiation GRN and use the GRN model to predict and control the differentiation process. His work promises to provide a quantitative understanding of the CD4+ T cell differentiation process and open up new strategies for safer and more effective cell-based cancer therapy. Dr. Zhu received his PhD from the California Institute of Technology, Pasadena and his BS from Hong Kong University of Science and Technology, Hong Kong.