Biology subjects

Chaft, J. E.

Publications and source records attributed to Chaft, J. E..

3 recordsLinked to original sources

bioRxiv2025

Novel Predictive Spatial Biomarker in Non-Small Cell Lung Carcinoma: The Diversity of Niches Unlocking Treatment Sensitivity (DONUTS)

Probabilistic spatial modelling techniques developed on large-scale tumor-immune Atlases ([~]35M individually mapped cells; 50,000 high power fields) were used to characterize predictive features of treatment-responsive lung cancer. We identified CD8+FoxP3+ cell density as a robust pre-treatment biomarker for outcomes across disease stages and therapy types. In parallel, single-cell RNAseq studies of CD8+FoxP3+ T-cells revealed an activated, early effector phenotype, substantiating an anti-tumor role, and contrasting with CD4+FoxP3+ T-regulatory cells. A spatial biomarker was developed using an empirical probabilistic model to define the immediate cell neighbors or niche surrounding CD8+FoxP3+ cells and proximity to the tumor-stromal boundary. The resultant Diversity of Niches Unlocking Treatment Sensitivity (DONUTS) are more prevalent than the CD8+FoxP3+ cells themselves, mitigating sampling error in small biopsies. Further, the DONUTS only require four markers, are additive to PD-L1, and associate with tertiary lymphoid structure counts. Taken together, the DONUTS represent a next-generation predictive biomarker poised for clinical implementation. HIGHLIGHTSO_LILarge-scale tumor-immune Atlases drive robust computational biomarker development C_LIO_LICD8+FoxP3+ cells are anti-tumor T-cells and predict response to therapy C_LIO_LIThe niches or spatial donuts around CD8+FoxP3+ cells boost biomarker performance C_LIO_LICD8+FoxP3+ donuts are hallmarks of a larger immune organization that includes TLS C_LI

pathology↗

bioRxiv2021

Regional and clonal T cell dynamics at single cell resolution in immune checkpoint blockade

Paired T cell receptor and RNA single cell sequencing (scTCR/RNA-seq) has allowed for enhanced resolution of clonal T cell dynamics in cancer. Here, we report a scTCR/RNA-seq dataset of 162,062 single T cells from 31 tissue regions, including tumor, adjacent normal tissues, and lymph nodes (LN), from three patients who underwent resections for progressing lung cancers after immune checkpoint blockade (ICB). We found marked regional heterogeneity in tumor persistence that was associated with heterogeneity in CD4 and CD8 T cell phenotypes; regions with persistent cancer cells were enriched for follicular helper CD4 T cells (TFH), regulatory T cells (Treg), and exhausted CD8 T cells. Clonal analysis demonstrated that highly-expanded T cell clones were predominantly of the CD8 subtype, were ubiquitously present across all sampled regions, found in the peripheral circulation, and expressed gene signatures of large and dual-expanded clones that have been predictive of response to ICB. Longitudinal tracking of CD8 T cell clones in the peripheral blood revealed that the persistence of ubiquitous CD8 T cell clones, as well as phenotypically distinct clones with tumor-reactive features, correlated with systemic tumor control. Finally, tracking CD8 T cell clones across tissues revealed the presence of TCF-1+ precursor exhausted CD8 T cells in tumor draining LNs that were clonally linked to expanded exhausted CD8 T cells in tumors. Altogether, this comprehensive scTCR/RNA-seq dataset with regional, longitudinal, and clonal resolution provides fundamental insights into the tissue distribution, persistence, and differentiation trajectories of ICB-responsive T cells that underlie clinical responses to ICB.

immunology↗

bioRxiv2018

YES1 amplification: a mechanism of acquired resistance to EGFR inhibitors identified by transposon mutagenesis and clinical genomics

In approximately 30% of patients with EGFR-mutant lung adenocarcinomas whose disease progresses on EGFR inhibitors, the basis for acquired resistance remains unclear. We have integrated transposon mutagenesis screening in an EGFR-mutant cell line and clinical genomic sequencing in cases of acquired resistance to identify novel mechanisms of resistance to EGFR inhibitors. The most prominent candidate genes identified by insertions in or near the genes during the screen were MET, a gene whose amplification is known to mediate resistance to EGFR inhibitors, and the gene encoding the Src family kinase YES1. Cell clones with transposon insertions that activated expression of YES1 exhibited resistance to all three generations of EGFR inhibitors and sensitivity to pharmacologic and siRNA-mediated inhibition of YES1. Analysis of clinical genomic sequencing data from cases of acquired resistance to EGFR inhibitors revealed amplification of YES1 in 5 cases, 4 of which lacked any other known mechanisms of resistance. Pre-inhibitor samples, available for 2 of the 5 patients, lacked YES1 amplification. None of 136 post-inhibitor samples had detectable amplification of other Src family kinases (SRC, FYN). YES1 amplification was also found in 2 of 17 samples from ALK fusion-positive lung cancer patients who had progressed on ALK TKIs. Taken together, our findings identify acquired amplification of YES1 as a novel, recurrent, and targetable mechanism of resistance to EGFR inhibition in EGFR-mutant lung cancers, and demonstrate the utility of transposon mutagenesis in discovering clinically relevant mechanisms of drug resistance.\n\nSIGNIFICANCEDespite high response rates to treatment with small molecule inhibitors of EGFR tyrosine kinase activity, patients with EGFR-mutant lung adenocarcinomas eventually develop resistance to these drugs. In many cases, the basis of acquired resistance remains unclear. We have used a transposon mutagenesis screen in an EGFR-mutant cell line and clinical genomic sequencing in cases of acquired resistance to identify amplification of YES1 as a novel and targetable mechanism of resistance to EGFR inhibitors in EGFR-mutant lung cancers.

cancer biology↗