BME Colloquium Series: Kevin A. Janes, Ph.D.

A Single-Cell Gene-Expression Module in Basal-Like Breast Cancers

Assistant Professor, Department of Biomedical Engineering, University of Virginia

Abstract

Cell-to-cell variations and asymmetries in gene and protein expression play an important role in the development and function of many tissues. But, how do we identify the heterogeneities in the first place? In this talk, I will present results from a new technique, called stochastic sampling, that attempts to address this general problem. Stochastic sampling involves the repeated, random selection of very-small cell populations (˜10 cells) followed by quantitative gene-expression profiling and simple statistical analysis (Nat Methods 7:311-7 [2010]). We combine laser-capture microdissection, a customized single-cell amplification protocol, quantitative PCR, and oligonucleotide microarrays to implement stochastic sampling in an in vitro model of mammary-gland morphogenesis. Our analysis identified hundreds of genes whose expression dichotomizes when human breast-epithelial cells are cultured as glandular structures. We are working to unravel the mechanisms that interconnect a reciprocal dichotomy between transforming growth factor-b signaling and the junD transcription factor. This endogenous pathway may be particularly relevant for a subtype of breast cancer, called basal-like carcinoma, which is known to be strongly heterogeneous at the single-cell level.