Highly Multiplexed, Quantitative Single Cell Proteomics for Fundamental and Clinical
Applications in Oncology
Jim Heath
NSBCC Cancer Center and
Caltech Division of Chemistry and Chemical Engineering
MC 127-72 Pasadena, CA 91125
Over the past few years we have developed an enabling microfluidic technology called the
Single Cell Barcode Chip (SCBC). For this platform, single cells are isolated into 1-2 nanoliter
volume microchambers, and each microchamber is equipped with a miniaturized antibody array
in the form of a barcode. The platform permits up to 20 cytoplasmic, membrane, and/or secreted
proteins to be quantitatively assayed from individual cells, with up to 1500 single cells analyzed
in parallel. We have applied this technology in multiple settings, and I will discuss a clinical and
a fundamental application. The clinical application involves separately profiling the engineered
and acquired immune responses in melanoma cancer patients participating in an engineered
adoptive T cell immunotherapy trial. For this study, we have characterized the functional
performance of several tumor-antigen-specific T cell phenotypes. The resultant analysis
provides deep insights into the therapy, and those insights are being utilized to redesign a followon phase 2 trial. For the fundamental application, we have investigated the transition from
normoxia to hypoxia in individual cancer cells. A theoretical analysis of the single cell
proteomic profiles, within the context of a maximum entropy thermodynamic framework,
indicates that the transition from normoxia to hypoxia is actually a second order phase transition
that occurs near 1.5% O2 pressure. This result has a number of ramifications, including
implications for therapeutic resistance, that haven’t been previously considered.