Biology subjects

Farkas, A. M.

Publications and source records attributed to Farkas, A. M..

4 recordsLinked to original sources

bioRxiv2024

Natural Killer Cell Dysfunction In Human Bladder Cancer Is Caused By Tissue-Specific Suppression of SLAMF6 Signaling

NK cells are innate lymphocytes critical for surveillance of viruses and tumors, however the mechanisms underlying NK cell dysfunction in cancer are incompletely understood. We assessed the effector function of NK cells from bladder cancer patients and found severe dysfunction in NK cells derived from tumors versus peripheral blood. While both peripheral and tumor-infiltrating NK cells exhibited conserved patterns of inhibitory receptor over-expression, this did not explain the observed defects in NK surveillance in bladder tumors. Rather, TME-specific TGF-{beta} and metabolic perturbations such as hypoxia directly suppressed NK cell function. Specifically, an oxygen-dependent reduction in signaling through SLAMF6 was mechanistically responsible for poor NK cell function, as tumor-infiltrating NK cells cultured ex vivo under normoxic conditions exhibited complete restoration of function, while deletion of SLAMF6 abrogated NK cell cytolytic function even under normoxic conditions. Collectively, this work highlights the role of tissue-specific factors in dictating NK cell function, and implicates SLAMF6 signaling as a rational target for immuno-modulation to improve NK cell function in bladder cancer. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=124 SRC="FIGDIR/small/591366v2_ufig1.gif" ALT="Figure 1"> View larger version (31K): org.highwire.dtl.DTLVardef@18ff2faorg.highwire.dtl.DTLVardef@1991cb6org.highwire.dtl.DTLVardef@12c1a94org.highwire.dtl.DTLVardef@84f87b_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

bioRxiv2022

Elevated HLA-E and NKG2A as a consequence of chronic immune activation defines resistance to M. bovis BCG immunotherapy in Non-Muscle-Invasive Bladder Cancer

Mycobacterium bovis Bacillus Calmette-Guerin (BCG), the first-line treatment for non-muscle invasive bladder cancer (NMIBC), promotes the production of inflammatory cytokines, particularly interferon (IFN)-{gamma}. Prolonged inflammation and IFN-{gamma} exposure are known to cause an adaptive immune response, enabling immune escape and proliferation by tumor cells. We investigated HLA-E and NKG2A, a novel T and NK cell checkpoint pathway, as a driver of adaptive resistance in BCG unresponsive NMIBC. We observed ubiquitous inflammation in all patients after BCG immunotherapy, regardless of recurrence status. IFN-{gamma} was shown to drive tumor expression of HLA-E and PD-L1. Further, NKG2A-expressing NK and CD8 T cells were enriched in BCG unresponsive tumors and with enhanced capacity for cytolytic functions. Strikingly, in situ spatial analyses revealed that HLA-EHIGH tumors are activated to recruit NK and T cells via chemokine production, potentially sparing HLA-ELOW tumors that would otherwise be susceptible to lysis. Finally, blood-derived NK cells retained anti-tumor functions at the time of tumor recurrence. These data support combined NKG2A and PD-L1 blockade for BCG unresponsive disease.

immunology↗

bioRxiv2022

NKG2A and HLA-E define a novel alternative immune checkpoint axis in bladder cancer

PD-1/PD-L1-blockade immunotherapies have limited efficacy in the treatment of muscle-invasive bladder cancer (MIBC) and metastatic urothelial carcinoma. Here, we show that KLRC1 (NKG2A) expression associates with improved survival and responsiveness to PD-L1 blockade immunotherapy in CD8Ahigh bladder tumors. The loss of antigen presentation is a common mechanism for tumor escape in bladder cancer. NKG2A+ CD8 T cells are able to circumvent HLA-ABC loss through TCR-independent cytotoxicity, which is partly mediated by DNAM-1. In bladder tumors, NKG2A is acquired on a subset of PD-1+ CD8 T cells, alongside stronger tissue-residency memory features, TCR-independent cytotoxicity and evidence of recent proliferation. HLA-E is low but variably expressed on bladder tumors. When expressed, NKG2A+ CD8 T cell anti-tumor responses to HLA-ABC-deficient tumors are inhibited and partly restored upon NKG2A blockade. Overall, our study identifies an alternative path for CD8 T cell exhaustion, that is mediated by NKG2A upregulation and TCR-independent cytotoxicity.

immunology↗

bioRxiv2020

Myeloid cell-associated resistance to PD-1/PD-L1 blockade in urothelial cancer revealed through bulk and single-cell RNA sequencing

Adaptive immunity and tumor-promoting inflammation exist in delicate balance in individual tumor microenvironments; however, the role of this balance in defining sensitivity and resistance to PD-1/PD-L1 blockade therapy in urothelial cancer and other malignancies is poorly understood. We pursued an unbiased systems biology approach using bulk RNA sequencing data to examine pre-treatment molecular features associated with sensitivity to PD-1/PD-L1 blockade in patients with metastatic urothelial cancer and identified an adaptive_immune_response module associated with response and an inflammatory_response module and stromal module associated with resistance. We mapped these gene modules onto single-cell RNA sequencing data demonstrating the adaptive_immune_response module emanated predominantly from T, NK, and B cells, the inflammatory_response module from monocytes/macrophages, and the stromal module from fibroblasts. The adaptive_immune_response:inflammatory_response module expression ratio in individual tumors, reflecting the balance between antitumor immunity and tumor-associated inflammation and coined the 2IR score, best correlated with clinical outcomes and was validated in an independent cohort. Individual monocytes/macrophages with low 2IR scores demonstrated upregulation of proinflammatory genes including IL1B and downregulation of antigen presentation genes, were unrelated to classical M1 versus M2 polarization, and were enriched in pre-treatment peripheral blood from patients with PD-L1 blockade-resistant metastatic urothelial cancer. Single sentence summaryProinflammatory monocytes/macrophages, present in tumor and blood, are associated with resistance to immune checkpoint blockade in urothelial cancer.

genomics↗