Chemotherapy, radiation therapy, as well as targeted anticancer agents can induce clinically relevant tumor-targeting immune responses, which critically rely on the antigenicity of malignant cells ...and their capacity to generate adjuvant signals. In particular, immunogenic cell death (ICD) is accompanied by the exposure and release of numerous damage-associated molecular patterns (DAMPs), which altogether confer a robust adjuvanticity to dying cancer cells, as they favor the recruitment and activation of antigen-presenting cells. ICD-associated DAMPs include surface-exposed calreticulin (CALR) as well as secreted ATP, annexin A1 (ANXA1), type I interferon, and high-mobility group box 1 (HMGB1). Additional hallmarks of ICD encompass the phosphorylation of eukaryotic translation initiation factor 2 subunit-α (EIF2S1, better known as eIF2α), the activation of autophagy, and a global arrest in transcription and translation. Here, we outline methodological approaches for measuring ICD markers in vitro and ex vivo for the discovery of next-generation antineoplastic agents, the development of personalized anticancer regimens, and the identification of optimal therapeutic combinations for the clinical management of cancer.
In multiple oncological settings, expression of the coinhibitory ligand PD-L1 by malignant cells and tumor infiltration by immune cells expressing coinhibitory receptors such as PD-1, CTLA4, LAG-3, ...or TIM-3 conveys prognostic or predictive information. Conversely, the impact of these features of the tumor microenvironment on disease outcome among high-grade serous carcinoma (HGSC) patients remains controversial.
We harnessed a retrospective cohort of 80 chemotherapy-naïve HGSC patients to investigate PD-L1 expression and tumor infiltration by CD8
T cells, CD20
B cells, DC-LAMP
dendritic cells as well as by PD-1
, CTLA4
, LAG-3
, and TIM-3
cells in relation with prognosis and function orientation of the tumor microenvironment. IHC data were complemented with transcriptomic and functional studies on a second prospective cohort of freshly resected HGSC samples.
analysis of publicly available RNA expression data from 308 HGSC samples was used as a confirmatory approach.
High levels of PD-L1 and high densities of PD-1
cells in the microenvironment of HGSCs were strongly associated with an immune contexture characterized by a robust T
1 polarization and cytotoxic orientation that enabled superior clinical benefits. Moreover, PD-1
TIM-3
CD8
T cells presented all features of functional exhaustion and correlated with poor disease outcome. However, although PD-L1 levels and tumor infiltration by TIM-3
cells improved patient stratification based on the intratumoral abundance of CD8
T cells, the amount of PD-1
cells failed to do so.
Our data indicate that PD-L1 and TIM-3 constitute prognostically relevant biomarkers of active and suppressed immune responses against HGSC, respectively.
In some settings, cancer cells responding to treatment undergo an immunogenic form of cell death that is associated with the abundant emission of danger signals in the form of damage-associated ...molecular patterns. Accumulating preclinical and clinical evidence indicates that danger signals play a crucial role in the (re-)activation of antitumor immune responses
, thus having a major impact on patient prognosis. We have previously demonstrated that the presence of calreticulin on the surface of malignant blasts is a positive prognostic biomarker for patients with acute myeloid leukemia (AML). Calreticulin exposure not only correlated with enhanced T-cell-dependent antitumor immunity in this setting but also affected the number of circulating natural killer (NK) cells upon restoration of normal hematopoiesis. Here, we report that calreticulin exposure on malignant blasts is associated with enhanced NK cell cytotoxic and secretory functions, both in AML patients and
in mice. The ability of calreticulin to stimulate NK-cells relies on CD11c
CD14
cells that, upon exposure to CRT, express higher levels of IL-15Rα, maturation markers (CD86 and HLA-DR) and CCR7. CRT exposure on malignant blasts also correlates with the upregulation of genes coding for type I interferon. This suggests that CD11c
CD14
cells have increased capacity to migrate to secondary lymphoid organs, where can efficiently deliver stimulatory signals (IL-15Rα/IL-15) to NK cells. These findings delineate a multipronged, clinically relevant mechanism whereby surface-exposed calreticulin favors NK-cell activation in AML patients.
A high density of tumor-infiltrating CD8
T cells and CD20
B cells correlates with prolonged survival in patients with a wide variety of human cancers, including high-grade serous ovarian carcinoma ...(HGSC). However, the potential impact of mature dendritic cells (DCs) in shaping the immune contexture of HGSC, their role in the establishment of T cell-dependent antitumor immunity, and their potential prognostic value for HGSC patients remain unclear. We harnessed immunohistochemical tests and biomolecular analyses to demonstrate that a high density of tumor-infiltrating DC-LAMP
DCs is robustly associated with an immune contexture characterized by T
1 polarization and cytotoxic activity. We showed that both mature DCs and CD20
B cells play a critical role in the generation of a clinically-favorable cytotoxic immune response in HGSC microenvironment. In line with this notion, robust tumor infiltration by both DC-LAMP
DCs and CD20
B cells was associated with most favorable overall survival in two independent cohorts of chemotherapy-naïve HGSC patients. Our findings suggest that the presence of mature, DC-LAMP
DCs in the tumor microenvironment may represent a novel, powerful prognostic biomarker for HGSC patients that reflects the activation of clinically-relevant anticancer immunity.
While type I interferon (IFN) is best known for its key role against viral infection, accumulating preclinical and clinical data indicate that robust type I IFN production in the tumor ...microenvironment promotes cancer immunosurveillance and contributes to the efficacy of various antineoplastic agents, notably immunogenic cell death inducers. Here, we report that malignant blasts from patients with acute myeloid leukemia (AML) release type I IFN via a Toll-like receptor 3 (TLR3)-dependent mechanism that is not driven by treatment. While in these patients the ability of type I IFN to stimulate anticancer immune responses was abolished by immunosuppressive mechanisms elicited by malignant blasts, type I IFN turned out to exert direct cytostatic, cytotoxic and chemosensitizing activity in primary AML blasts, leukemic stem cells from AML patients and AML xenograft models. Finally, a genetic signature of type I IFN signaling was found to have independent prognostic value on relapse-free survival and overall survival in a cohort of 132 AML patients. These findings delineate a clinically relevant, therapeutically actionable and prognostically informative mechanism through which type I IFN mediates beneficial effects in patients with AML.
Intratumoral tertiary lymphoid structures (TLSs) have been associated with improved outcome in various cohorts of patients with cancer, reflecting their contribution to the development of ...tumor-targeting immunity. Here, we demonstrate that high-grade serous ovarian carcinoma (HGSOC) contains distinct immune aggregates with varying degrees of organization and maturation. Specifically, mature TLSs (mTLS) as forming only in 16% of HGSOCs with relatively elevated tumor mutational burden (TMB) are associated with an increased intratumoral density of CD8
effector T (T
) cells and TIM3
PD1
, hence poorly immune checkpoint inhibitor (ICI)-sensitive, CD8
T cells. Conversely, CD8
T cells from immunologically hot tumors like non-small cell lung carcinoma (NSCLC) are enriched in ICI-responsive TCF1
PD1
T cells. Spatial B-cell profiling identifies patterns of in situ maturation and differentiation associated with mTLSs. Moreover, B-cell depletion promotes signs of a dysfunctional CD8
T cell compartment among tumor-infiltrating lymphocytes from freshly isolated HGSOC and NSCLC biopsies. Taken together, our data demonstrate that - at odds with NSCLC - HGSOC is associated with a low density of follicular helper T cells and thus develops a limited number of mTLS that might be insufficient to preserve a ICI-sensitive TCF1
PD1
CD8
T cell phenotype. These findings point to key quantitative and qualitative differences between mTLSs in ICI-responsive vs ICI-irresponsive neoplasms that may guide the development of alternative immunotherapies for patients with HGSOC.
BackgroundThe immunological microenvironment of primary high-grade serous carcinomas (HGSCs) has a major impact on disease outcome. Conversely, little is known on the microenvironment of metastatic ...HGSCs and its potential influence on patient survival. Here, we explore the clinical relevance of the immunological configuration of HGSC metastases.MethodsRNA sequencing was employed on 24 paired primary tumor microenvironment (P-TME) and metastatic tumor microenvironment (M-TME) chemotherapy-naive HGSC samples. Immunohistochemistry was used to evaluate infiltration by CD8+ T cells, CD20+ B cells, DC-LAMP+ (lysosomal-associated membrane protein 3) dendritic cells (DCs), NKp46+ (natural killer) cells and CD68+CD163+ M2-like tumor-associated macrophages (TAMs), abundance of PD-1+ (programmed cell death 1), LAG-3+ (lymphocyte-activating gene 3) cells, and PD-L1 (programmed death ligand 1) expression in 80 samples. Flow cytometry was used for functional assessments on freshly resected HGSC samples.Results1468 genes were differentially expressed in the P-TME versus M-TME of HGSCs, the latter displaying signatures of extracellular matrix remodeling and immune infiltration. M-TME infiltration by immune effector cells had little impact on patient survival. Accordingly, M-TME-infiltrating T cells were functionally impaired, but not upon checkpoint activation. Conversely, cytokine signaling in favor of M2-like TAMs activity appeared to underlie inhibited immunity in the M-TME and poor disease outcome.ConclusionsImmunosuppressive M2-like TAM infiltrating metastatic sites limit clinically relevant immune responses against HGSCs.
Accumulating evidence indicates that immune checkpoint inhibitors (ICIs) can restore CD8
+
cytotoxic T lymphocyte (CTL) functions in preclinical models of acute myeloid leukemia (AML). However, ICIs ...targeting programmed cell death 1 (PDCD1, best known as PD-1) and cytotoxic T lymphocyte-associated protein 4 (CTLA4) have limited clinical efficacy in patients with AML. Natural killer (NK) cells are central players in AML-targeting immune responses. However, little is known on the relationship between co-inhibitory receptors expressed by NK cells and the ability of the latter to control AML. Here, we show that hepatitis A virus cellular receptor 2 (HAVCR2, best known as TIM-3) is highly expressed by NK cells from AML patients, correlating with improved functional licensing and superior effector functions. Altogether, our data indicate that NK cell frequency as well as TIM-3 expression levels constitute prognostically relevant biomarkers of active immunity against AML.
BackgroundAdjuvanticity, which is the ability of neoplastic cells to deliver danger signals, is critical for the host immune system to mount spontaneous and therapy-driven anticancer immune ...responses. One of such signals, i.e., the exposure of calreticulin (CALR) on the membrane of malignant cells experiencing endoplasmic reticulum (ER) stress, is well known for its role in the activation of immune responses to dying cancer cells. However, the potential impact of CALR on the immune contexture of primary and metastatic high-grade serous carcinomas (HGSCs) and its prognostic value for patients with HGSC remains unclear.MethodWe harnessed a retrospective cohort of primary (no = 152) and metastatic (no = 74) tumor samples from HGSC patients to investigate the CALR expression in relation with prognosis and function orientation of the tumor microenvironment. IHC data were complemented with transcriptomic and functional studies on second prospective cohort of freshly resected HGSC samples. In silico analysis of publicly available RNA expression data from 302 HGSC samples was used as a confirmatory approach.ResultsWe demonstrate that CALR exposure on the surface of primary and metastatic HGSC cells is driven by a chemotherapy-independent ER stress response and culminates with the establishment of a local immune contexture characterized by TH1 polarization and cytotoxic activity that enables superior clinical benefits.ConclusionsOur data indicate that CALR levels in primary and metastatic HGSC samples have robust prognostic value linked to the activation of clinically-relevant innate and adaptive anticancer immune responses.
Dendritic cells (DCs) have received considerable attention as potential targets for the development of novel cancer immunotherapies. However, the clinical efficacy of DC-based vaccines remains ...suboptimal, largely reflecting local and systemic immunosuppression at baseline. An autologous DC-based vaccine (DCVAC) has recently been shown to improve progression-free survival and overall survival in randomized clinical trials enrolling patients with lung cancer (SLU01, NCT02470468) or ovarian carcinoma (SOV01, NCT02107937), but not metastatic castration-resistant prostate cancer (SP005, NCT02111577), despite a good safety profile across all cohorts. We performed biomolecular and cytofluorometric analyses on peripheral blood samples collected prior to immunotherapy from 1000 patients enrolled in these trials, with the objective of identifying immunological biomarkers that may improve the clinical management of DCVAC-treated patients. Gene signatures reflecting adaptive immunity and T cell activation were associated with favorable disease outcomes and responses to DCVAC in patients with prostate and lung cancer, but not ovarian carcinoma. By contrast, the clinical benefits of DCVAC were more pronounced among patients with ovarian carcinoma exhibiting reduced expression of T cell-associated genes, especially those linked to T
H2
-like signature and immunosuppressive regulatory T (T
REG
) cells. Clinical responses to DCVAC were accompanied by signs of antitumor immunity in the peripheral blood. Our findings suggest that circulating signatures of antitumor immunity may provide a useful tool for monitoring the potency of autologous DC-based immunotherapy.
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