Epidemiologic studies have revealed that many cancer types display differences in incidence or outcomes between the sexes. In most cases, these differences are only partially explained by non-genetic factors such as hormonal differences, carcinogen exposure, lifestyle, and access to health care. Our understanding of how genetic factors contribute to differences in cancer incidence between the sexes remains incomplete. A fundamental genetic difference between the sexes is in chromosome composition. Relative to male somatic cells, female somatic cells have an extra X chromosome. Most genes on the second copy of chromosome X in females are inactivated via a process known as X-chromosome inactivation, which approximately equalizes the dosage of X-linked genes between males and females. Dr. Viswanathan's project tests the hypothesis that genetic alterations to the X chromosome in cancer may perturb this carefully regulated process and thereby contribute to differences in cancer incidence or pathogenic mechanisms between males and females.

Dr. Tai studies bacterial biofilms or aggregates of bacterial cells in an extracellular matrix. Biofilms play a critical role in many health and industry settings. Biofilm-forming bacteria and imbalance in patients’ gut microbiota have been found to correlate with cancer development, and cancer patients receiving therapy frequently suffer from bacterial infections. From the unique perspectives of microbiology, soft matter physics, and ecology, Dr. Tai aims to decipher how, at the single bacteria cell level, heterogeneities in cell shape, organization, and gene expression constitute the function and development of their collective communities: biofilms. His work is expected to deepen our understanding of bacterial biofilms and ultimately contribute to therapeutic strategies.

Dr. Gu [Fraternal Order of Eagles Fellow] is deciphering the combinatorial code of mammalian transcription regulation. The precise and robust regulation of gene expression is typically achieved through a combination of multiple transcription factors. However, we lack understanding of how a mammalian transcription system perceives, processes, and presents combinations of transcription factors. Dr. Gu will combine quantitative modeling and synthetic approaches to analyze the complex interactions among natural transcription regulatory proteins and apply the principles learned to engineer a programmable transcriptional platform with tunable logic. This work promises to deepen our understanding of mammalian transcription regulation and unlock new capabilities for emerging cell-based therapeutics.

Dr. Squyres [National Mah Jongg League Fellow] is using quantitative microscopy and cell biology approaches to study how bacteria in biofilms coordinate their behavior in space and time. Biofilms are dense, multicellular communities of bacteria embedded in an extracellular matrix. Biofilms often form during bacterial infections, resulting in infections that are difficult to treat and resist antibiotics; cancer patients are at particular risk for these types of infections. Dr. Squyres is currently investigating how the release of extracellular DNA, a key component of the biofilm matrix, is coordinated during biofilm development. Greater understanding of how bacteria function in biofilms can lead to new approaches to target these treatment-resistant infections.

Dr. Cissé [Merck Fellow] aims to define the functional importance of nutrient sensing within the tumor microenvironment. How cells sense and adapt to the availability of nutrients in their environment is incompletely understood, but one key pathway is the signaling system anchored by the mTORC1 kinase. The mTORC1 kinase regulates cell growth and metabolism in response to nutrients such as amino acids and glucose. Aberrant mTORC1 signaling is implicated in several cancers, including melanoma, known to be heavily influenced by factors in the microenvironment such as nutrient availability. Dr. Cissé aims to understand how tumor metabolism senses and responds to varying nutrient levels, which will be essential for developing novel therapeutic targets.

Dr. Cote is exploring embryonic development to better understand how cells cooperate and build complex tissues. Since cancer cells often erroneously redeploy developmental programs and behaviors, her research into how neighboring cells align will yield insights into how cancerous cells metastasize and invade other tissues. Dr. Cote is combining tissue-specific genetic manipulations and laser cell ablations with live imaging during Caenorhabditis elegans digestive tract development to reveal how intracellular organization in one cell type can influence the alignment, polarity, and function of cells in the neighboring tissues.