Search citation statements
Paper Sections
Citation Types
Year Published
Publication Types
Relationship
Authors
Journals
PurposeA subset of primary prostate cancer (PCa) expresses programmed death-ligand 1 (PD-L1), but whether they have unique tumor immune microenvironment (TIME) or genomic features is unclear.Experimental DesignWe selected PD-L1-positive high-grade and/or high-risk primary PCa, characterized tumor-infiltrating lymphocytes (TILS) with multiplex immunofluorescence, and identified genomic alterations in immunogenic and non-immunogenic tumor foci.ResultsOne-quarter of aggressive localized PCa cases (29/115) had tumor PD-L1 expression >5%. This correlated with increased density of CD8+ T cells, a large fraction co-expressing PD-1, versus absent PD-1 expression on sparse CD8 T cells in unselected cases. Most CD8+PD-1+ cells did not express terminal exhaustion markers (TIM-3 or LAG-3), while a subset expressed TCF1. Consistent with these CD8+PD-1+TCF1+ cells being progenitors, they were found in antigen-presenting-cell niches in close proximity to MHC II+ cells. CD8 T cell density in immunogenic PCa and renal cell carcinoma (RCC) was nearly identical. Shallow RB1 and BRCA2 losses, and deep deletions of CHD1, were prevalent; the latter being strongly associated with a dendritic cell gene set in TCGA. Tumor mutation burden was variable; neither high microsatellite instability nor CDK12 alterations were present.ConclusionsA subset of localized PCa is immunogenic, manifested by PD-L1 expression and CD8+ T cell content comparable to RCC. The CD8+ T cells include effector cells and exhausted progenitor cells, which may be expanded by ICIs. Genomic losses of RB1, BRCA2, and CHD1 may be drivers of this phenotype. These findings indicate that immunotherapies may be effective in biomarker-selected subpopulations of localized PCa patients.Statement of Translational RelevanceProstate cancer (PCa) is generally considered poorly immunogenic, with low expression of programmed death-ligand 1 (PD-L1) and low density of tumor-infiltrating immune cells. Accordingly, response rates to PD(L)-1 inhibition in unselected patients with advanced prostate cancer have been low. Here, we find that a substantial subset of aggressive primary PCa exhibits tumor PD-L1 expression and contains a high density of tumor-infiltrating lymphocytes. These lymphocytes contain sub-populations of exhausted progenitor CD8+ T cells and differentiated effector T cells, the hallmarks of ongoing anti-tumor immune response and a prerequisite for response to checkpoint inhibition. Furthermore, we identify genomic alterations that may be contributing to immunogenicity in these cases. These findings point to immune responses elicited in a subset of primary PCa, supporting the development of immune checkpoint blockade clinical trials in early-stage disease, such as biochemically recurrent PCa, that are driven by genomic features of the tumor or the immune microenvironment.
PurposeA subset of primary prostate cancer (PCa) expresses programmed death-ligand 1 (PD-L1), but whether they have unique tumor immune microenvironment (TIME) or genomic features is unclear.Experimental DesignWe selected PD-L1-positive high-grade and/or high-risk primary PCa, characterized tumor-infiltrating lymphocytes (TILS) with multiplex immunofluorescence, and identified genomic alterations in immunogenic and non-immunogenic tumor foci.ResultsOne-quarter of aggressive localized PCa cases (29/115) had tumor PD-L1 expression >5%. This correlated with increased density of CD8+ T cells, a large fraction co-expressing PD-1, versus absent PD-1 expression on sparse CD8 T cells in unselected cases. Most CD8+PD-1+ cells did not express terminal exhaustion markers (TIM-3 or LAG-3), while a subset expressed TCF1. Consistent with these CD8+PD-1+TCF1+ cells being progenitors, they were found in antigen-presenting-cell niches in close proximity to MHC II+ cells. CD8 T cell density in immunogenic PCa and renal cell carcinoma (RCC) was nearly identical. Shallow RB1 and BRCA2 losses, and deep deletions of CHD1, were prevalent; the latter being strongly associated with a dendritic cell gene set in TCGA. Tumor mutation burden was variable; neither high microsatellite instability nor CDK12 alterations were present.ConclusionsA subset of localized PCa is immunogenic, manifested by PD-L1 expression and CD8+ T cell content comparable to RCC. The CD8+ T cells include effector cells and exhausted progenitor cells, which may be expanded by ICIs. Genomic losses of RB1, BRCA2, and CHD1 may be drivers of this phenotype. These findings indicate that immunotherapies may be effective in biomarker-selected subpopulations of localized PCa patients.Statement of Translational RelevanceProstate cancer (PCa) is generally considered poorly immunogenic, with low expression of programmed death-ligand 1 (PD-L1) and low density of tumor-infiltrating immune cells. Accordingly, response rates to PD(L)-1 inhibition in unselected patients with advanced prostate cancer have been low. Here, we find that a substantial subset of aggressive primary PCa exhibits tumor PD-L1 expression and contains a high density of tumor-infiltrating lymphocytes. These lymphocytes contain sub-populations of exhausted progenitor CD8+ T cells and differentiated effector T cells, the hallmarks of ongoing anti-tumor immune response and a prerequisite for response to checkpoint inhibition. Furthermore, we identify genomic alterations that may be contributing to immunogenicity in these cases. These findings point to immune responses elicited in a subset of primary PCa, supporting the development of immune checkpoint blockade clinical trials in early-stage disease, such as biochemically recurrent PCa, that are driven by genomic features of the tumor or the immune microenvironment.
Tumor-associated macrophages are key immune cells associated with cancer progression. Here we sought to determine the role of macrophages in castration-resistant prostate cancer (CRPC) using a syngeneic model that reflected the mutational landscape of the disease. A transcriptomic analysis of CRPC tumors following macrophage depletion revealed lower molecular signatures for steroid and bile acid synthesis, indicating potential perturbation of cholesterol metabolism. Since cholesterol is the precursor of the five major classes of steroid hormones, we reasoned that macrophages were regulating androgen biosynthesis within the prostate tumor microenvironment. Indeed, macrophage depletion reduced the levels of androgens within prostate tumors and restricted androgen receptor (AR) nuclear localization in vitro and in vivo. Macrophages were cholesterol rich and had the ability to transfer cholesterol to tumor cells in vitro, and AR nuclear translocation was inhibited by activation of Liver X Receptor (LXR)-β, the master regulator of cholesterol homeostasis. Finally, combining macrophage depletion with androgen deprivation therapy increased survival, supporting the therapeutic potential of targeting macrophages in CRPC.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.