SUMMARY
Tumors are complex systems composed of genetically and transcriptionally heterogeneous cells, and
this variation has been implicated as a cause of drug resistance and mortality. Understanding intra-tumor
heterogeneity is therefore likely to have widespread scientific implications and clinical applications. The advent
of single-cell RNA-Seq has enabled the mapping of transcriptionally distinct states among cancer cells across
a wide range of tumor types and disease stages. In this project, I take a gene module-centric view to define cell
states in a rigorous and widely applicable manner. In my preliminary work, I have identified specific cancer cell
states that are conserved across many cancer types as well as some that are unique to specific tumors. This
proposal aims to further characterize these states in relation to the tumor microenvironment, with the goal of
furthering our understanding of tumors as complex dynamical systems amenable to therapeutic intervention. In
order to systematically map interactions between tumor cell populations within their native context, I will
integrate paired single-cell and spatial transcriptomic data obtained in primary patient samples. This will enable
me to identify cell populations that interact within the tumor, and to characterize the gene expression changes
that occur in these interactions. In order to further establish how cancer cell state function relates to the tumor
microenvironment, I will take advantage of experimental model systems amenable to perturbation. I will use
orthotopic mouse cancer models as a platform to deplete specific populations of the immune system and
measure their effect on cancer cell states. Next, I will perform co-culture experiments followed by
transcriptomic and phenotypic profiling to measure direct effects on one cell population on another.
Collectively, the experiments and algorithms proposed will significantly improve our understanding of
intratumoral heterogeneity through the lens of cancer cell states. Dissecting the complex interactions between
cancer cell states and immune cell populations will be of particular translational relevance, as it may enable the
rational design of immunotherapy regimens. The research proposed capitalizes on the strengths of the Yanai
lab in cutting-edge molecular techniques, computational innovation, and in vitro and in vivo modeling of cancer.
Together with the outlined training plan, this work will set me on a path to independent research as a
physician-scientist.