Biology subjects

Chatta, G.

Publications and source records attributed to Chatta, G..

3 recordsLinked to original sources

bioRxiv2023

Integrated single-cell analysis defines the epigenetic basis of castration-resistant prostate luminal cells

Understanding prostate response to castration and androgen receptor signaling inhibitors (ARSI) is critical to improving long-term prostate cancer (PCa) patient survival. Here we use a multi-omics approach on 229,794 single cells to create a mouse single-cell reference atlas better suited to interpreting mouse prostate biology and castration response. Our reference atlas refines single-cell annotations and provides chromatin context, which, when coupled with mouse lineage tracing demonstrates that the castration-resistant luminal cells are distinct from the pre-existent urethra- proximal stem/progenitor cells. Molecular pathway analysis and therapeutic studies further implicate JUN/FOS, WNT/{beta}-Catenin, FOXQ1, NF{kappa}B, and JAK/STAT pathways as the major drivers of castration- resistant luminal populations with high relevance to human PCa. Importantly, we demonstrate the utility of our datasets, which can be explored through an interactive portal (https://visportal.roswellpark.org/data/tang/), to aid in developing novel combination treatments with ARSI for advanced PCa patients. O_FIG O_LINKSMALLFIG WIDTH=164 HEIGHT=200 SRC="FIGDIR/small/530998v1_ufig1.gif" ALT="Figure 1"> View larger version (62K): org.highwire.dtl.DTLVardef@8bd384org.highwire.dtl.DTLVardef@1ebc004org.highwire.dtl.DTLVardef@8b4dbforg.highwire.dtl.DTLVardef@19d7052_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

bioRxiv2021

Glucocorticoid signaling delays castration-induced regression in murine models of prostate cancer

Androgen deprivation therapy (ADT) induces regression of recurrent and advanced prostate cancer (PrCa), but many tumors recur. To understand the response to ADT, changes in tumor volume were imaged after castration of murine PrCa models. While mouse (non-tumor) prostate begins to regress within two days of castration, murine PrCa regresses after a delay of 3-14 days in two distinct mouse models. Intra-tumoral androgens are undetectable after castration, but tumor cells proliferate during this period. Intratumoral glucocorticoids and glucocorticoid receptor (GR) protein increase, as does GR mRNA and a set of GR-regulated genes specifically in tumor epithelial cells identified using scRNAseq. A selective GR antagonist (CORT125281, relacorilant), in clinical trials for late-state PrCa, eliminates the delayed regression phenotype in both models. Thus, activated GR signaling and murine tumor proliferation following castration resembles the GR-dependent escape mechanism of castrate resistant PrCa. These results suggest simultaneous inhibition of GR and androgen receptor signaling could improve PrCa therapy. In briefAndrogen deprivation therapy for high risk and recurrent prostate cancers is initially effective, but ultimately fails; better understanding the mechanisms should improve therapy. In two murine prostate cancer models, GR signaling is activated immediately following castration, substituting for the acute reduction in AR signaling, and allowing for continued tumor growth. This continued growth is blocked by relacorilant, selective GR antagonist in clinical trials for late-state PrCa. HighlightsO_LIAndrogen deprivation therapy induces regression of prostate cancer, but tumors recur C_LIO_LIMurine PrCa continues to proliferate for 3-14 days in two distinct mouse prostate cancer models C_LIO_LITumor cells proliferate during this period, and intratumoral glucocorticoids and glucocorticoid receptor (GR) protein increase, as does GR mRNA and a set of GR-regulated genes C_LIO_LIRelacorilant, a selective GR antagonist in clinical trials for late-state PrCa, eliminates the delayed regression C_LI

cancer biology↗

bioRxiv2020

A circulating T-cell differentiation marker to predict response to immune checkpoint inhibitors

Immune checkpoint inhibitors (ICI) have revolutionized treatment for various cancers; however, durable response is limited to only a subset of patients. Discovery of blood-based biomarkers that reflect dynamic change of the tumor microenvironment, and predict response to ICI will markedly improve current treatment regimens. Here, we investigated a role of CX3C chemokine receptor 1 (CX3CR1), a marker of T-cell differentiation, in predicting response to ICI therapy. Successful treatment of tumor-bearing mice with ICI increased the frequency and T-cell receptor clonality of the peripheral CX3CR1+CD8+ T-cell subset that included an enriched repertoire of tumor-specific and tumor-infiltrating CD8+ T cells. Furthermore, an increase in the frequency of the CX3CR1+ subset in circulating CD8+ T cells early after initiation of anti-PD-1 therapy correlated with response and survival in patients with non-small cell lung cancer (NSCLC). Taken together, these data support T-cell CX3CR1 expression as a blood-based dynamic biomarker to predict response to ICI therapy.

immunology↗