Immunogenic cell death (ICD), a functionally peculiar type of apoptosis, represents a unique way to deliver danger-associated molecular patterns (DAMPs) to the tumor microenvironment. Once emitted by dying cancer cells, DAMPs orchestrate antigen-specific immune responses by acting on both innate and adaptive components of the immune system. Accumulating preclinical and clinical evidence indicates that one of these DAMPs, calreticulin (CALR) represents a novel powerful prognostic biomarker, reflecting the activation of a clinically relevant anticancer immune response in different cancer malignancies. Therefore, the assessment of CALR emission can provide a therapeutic tool for the stratification of cancer patients and the identification of individuals that are intrinsically capable to respond to a particular treatment. Here we describe methods for the quantification of CALR exposure in the tumor microenvironment of cancer patients by flow cytometry and immunohistochemistry.

• MeSH
• imunogenní buněčná smrt * MeSH
• imunohistochemie metody   MeSH
• kalretikulin analýza   imunologie   MeSH
• lidé MeSH
• nádorové biomarkery analýza   imunologie   MeSH
• nádorové mikroprostředí MeSH
• nádory imunologie   patologie   MeSH
• průtoková cytometrie metody   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH

BACKGROUND: Adjuvanticity, 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. METHOD: We 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. RESULTS: We 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. CONCLUSIONS: Our 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.

• MeSH
• dospělí MeSH
• kalretikulin imunologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• nádorové mikroprostředí genetika   imunologie   MeSH
• nádory vaječníků genetika   imunologie   MeSH
• prognóza MeSH
• sekvenování transkriptomu MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• stres endoplazmatického retikula MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH

Distinct cellular level of the Ca2+-binding chaperone calreticulin (CRT) is essential for correct embryonal cardiac development and postnatal function. However, CRT is also a potential autoantigen eliciting formation of antibodies (Ab), whose role is not yet clarified. Immunization with CRT leads to cardiac injury, while overexpression of CRT in cardiomyocytes induces dilated cardiomyopathy (DCM) in animals. Hence, we analysed levels of anti-CRT Ab and calreticulin in the sera of patients with idiopatic DCM and hypertrophic cardiomyopathy (HCM). ELISA and immunoblot using human recombinant CRT and Pepscan with synthetic, overlapping decapeptides of CRT were used to detect anti-CRT Ab. Serum CRT concentration was tested by ELISA. Significantly increased levels of anti-CRT Ab of isotypes IgA (p < 0.001) and IgG (p < 0.05) were found in patients with both DCM (12/34 seropositive for IgA, 7/34 for IgG) and HCM (13/38 seropositive for IgA, 11/38 for IgG) against healthy controls (2/79 for IgA, 1/79 for IgG). Titration analysis in seropositive DCM and HCM patients documented anti-CRT Ab detected at 1/1600 dilution for IgG and 1/800 for IgA (and IgA1) and at least at 1/200 dilution for IgA2, IgG1, IgG2 and IgG3. Pepscan identified immunogenic CRT epitopes recognized by IgA and IgG Ab of these patients. Significantly increased levels of CRT relative to healthy controls were found in sera of patients with HCM (p < 0.01, 5/19). These data extend the knowledge of seroprevalence of anti-CRT Ab and CRT, and suggest possible involvement of autoimmune mechanisms directed to CRT in some forms of cardiomyopathies, which are clinically heterogeneous.

• MeSH
• autoantigeny krev   imunologie   MeSH
• autoimunita MeSH
• autoprotilátky krev   imunologie   MeSH
• biologické markery MeSH
• dilatační kardiomyopatie krev   diagnóza   imunologie   MeSH
• dospělí MeSH
• ELISA MeSH
• hypertrofická kardiomyopatie krev   diagnóza   imunologie   MeSH
• imunoglobulin A krev   imunologie   MeSH
• imunoglobulin G krev   imunologie   MeSH
• kalretikulin krev   imunologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• senioři MeSH
• studie případů a kontrol MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Recent studies have identified molecular events characteristic of immunogenic cell death (ICD), including surface exposure of calreticulin (CRT), the heat shock proteins HSP70 and HSP90, the release of high-mobility group box protein 1 (HMGB1) and the release of ATP from dying cells. We investigated the potential of high hydrostatic pressure (HHP) to induce ICD in human tumor cells. HHP induced the rapid expression of HSP70, HSP90 and CRT on the cell surface. HHP also induced the release of HMGB1 and ATP. The interaction of dendritic cells (DCs) with HHP-treated tumor cells led to a more rapid rate of DC phagocytosis, upregulation of CD83, CD86 and HLA-DR and the release of interleukin IL-6, IL-12p70 and TNF-α. DCs pulsed with tumor cells killed by HHP induced high numbers of tumor-specific T cells. DCs pulsed with HHP-treated tumor cells also induced the lowest number of regulatory T cells. In addition, we found that the key features of the endoplasmic reticulum stress-mediated apoptotic pathway, such as reactive oxygen species production, phosphorylation of the translation initiation factor eIF2α and activation of caspase-8, were activated by HHP treatment. Therefore, HHP acts as a reliable and potent inducer of ICD in human tumor cells.

• MeSH
• adenosintrifosfát sekrece   MeSH
• aktivace enzymů imunologie   MeSH
• antigeny CD86 biosyntéza   MeSH
• apoptóza imunologie   MeSH
• CD antigeny biosyntéza   MeSH
• dendritické buňky imunologie   MeSH
• eukaryotický iniciační faktor 2 metabolismus   MeSH
• fagocytóza imunologie   MeSH
• fosforylace MeSH
• HLA-DR antigeny biosyntéza   MeSH
• hydrostatický tlak MeSH
• imunoglobuliny biosyntéza   MeSH
• interleukin-12 sekrece   MeSH
• interleukin-6 sekrece   MeSH
• kalretikulin biosyntéza   imunologie   MeSH
• kaspasa 8 metabolismus   MeSH
• lidé MeSH
• membránové glykoproteiny biosyntéza   MeSH
• membránové proteiny biosyntéza   MeSH
• nádorové buněčné linie MeSH
• nádory imunologie   MeSH
• protein HMGB1 imunologie   sekrece   MeSH
• proteiny tepelného šoku HSP70 biosyntéza   imunologie   MeSH
• proteiny tepelného šoku HSP90 biosyntéza   imunologie   MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• regulační T-lymfocyty imunologie   MeSH
• stres endoplazmatického retikula imunologie   MeSH
• TNF-alfa sekrece   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Immunogenic cell death is characterized by the early surface exposure of chaperones including calreticulin and HSPs, which affect dendritic cell (DC) maturation and the uptake and presentation of tumor antigens. It has also been shown that it is characterized by the late release of high mobility group box 1 (HMGB1), which acts through Toll-like receptor 4 (TLR4) and augments the presentation of antigens from dying tumor cells to DCs. Most of the data on immunogenic tumor cell death were obtained using mouse models. In this study, we investigated the capacity of clinically used chemotherapeutics to induce immunogenic cell death in human tumor cell lines and primary tumor cells. We found that only anthracyclines induced a rapid translocation of calreticulin, HSP70, and HSP90 to the cell surface and the release of HMGB1 12 hours after the treatment. The interaction of immature DCs with immunogenic tumor cells led to an increased tumor cell uptake and induces moderate phenotypic maturation of DCs. Killed tumor cell-loaded DCs efficiently stimulated tumor-specific IFN-γ-producing T cells. DCs pulsed with killed immunogenic tumor cells also induced significantly lower numbers of regulatory T cells than those pulsed with nonimmunogenic tumor cells. These data indicate that human prostate cancer, ovarian cancer, and acute lymphoblastic leukemia cells share the key features of immunogenic cell death with mice tumor cells. These data also identify anthracyclines as anticancer drugs capable of inducing immunogenic cell death in sensitive human tumor cells.

• MeSH
• akutní lymfatická leukemie farmakoterapie   imunologie   patologie   MeSH
• antracykliny imunologie   farmakologie   MeSH
• buněčná smrt účinky léků   imunologie   MeSH
• dendritické buňky imunologie   patologie   MeSH
• fagocytóza účinky léků   imunologie   MeSH
• kalretikulin biosyntéza   imunologie   MeSH
• lidé MeSH
• nádorové buněčné linie MeSH
• nádory prostaty farmakoterapie   imunologie   patologie   MeSH
• nádory vaječníků farmakoterapie   imunologie   patologie   MeSH
• nádory farmakoterapie   imunologie   patologie   MeSH
• protein HMGB1 imunologie   sekrece   MeSH
• proteiny tepelného šoku HSP70 biosyntéza   imunologie   MeSH
• proteiny tepelného šoku HSP90 biosyntéza   imunologie   MeSH
• T-lymfocyty účinky léků   imunologie   MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Calreticulin, upon translocation to the cell surface, plays a critical role in the recognition of tumour cells and in experimentally induced cellular anti-tumour immunity. However, less is known about anti-calreticulin antibodies and their role in malignancies. Using enzyme-linked immunosorbent assay (ELISA), we found immunoglobulin (Ig)A and/or IgG anti-calreticulin antibodies in sera of approximately 63% of patients with hepatocellular carcinoma (HCC), 57% of patients with colorectal adenocarcinoma (CRA) and 47% of patients with pancreatic adenocarcinoma (PACA), while healthy controls, patients with viral hepatitis C and with chronic pancreatitis reached only 2%, 20% and 31% seropositivity, respectively. We found significantly elevated mean levels of IgA anti-calreticulin antibodies (P < 0.001) in patients with HCC (78.7 +/- 52.3 AU, mean +/- standard deviation), PACA (66.5 +/- 30.9 AU) and CRA (61.8 +/- 25.8 AU) when compared to healthy controls (41.4 +/- 19.2 AU). Significantly elevated mean levels of IgG anti-calreticulin antibodies (P < 0.001) were detected in patients with HCC (121.9 +/- 94.2 AU), gall bladder adenocarcinoma (118.4 +/- 80.0 AU) and PACA (88.7 +/- 55.6 AU) when compared to healthy controls (56.7 +/- 22.9 AU). Pepscan analysis revealed a large number of antigenic epitopes of calreticulin recognized by both IgA and IgG antibodies of patients with HCC and PACA, indicating robust systemic immune response. Moreover, significantly elevated levels of antibodies against peptide KGEWKPRQIDNP (P < 0.001) in these patients, tested by ELISA, confirmed the distinct character of antibody reactivity against calreticulin. The high occurrence and specificity of serum anti-calreticulin autoantibodies in the majority of patients with some gastrointestinal malignancies provide the evidence for their possible clinical relevance.

• MeSH
• adenokarcinom krev   imunologie   MeSH
• autoantigeny imunologie   MeSH
• autoprotilátky krev   imunologie   MeSH
• B-lymfocyty imunologie   MeSH
• chronická hepatitida C krev   imunologie   MeSH
• dospělí MeSH
• ELISA MeSH
• epitopy imunologie   MeSH
• hepatocelulární karcinom krev   imunologie   MeSH
• imunoglobulin A krev   imunologie   MeSH
• imunoglobulin G krev   imunologie   MeSH
• kalretikulin imunologie   MeSH
• kolorektální nádory krev   imunologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• nádorové proteiny imunologie   MeSH
• nádory jater krev   imunologie   MeSH
• nádory slinivky břišní krev   imunologie   MeSH
• nádory žlučníku krev   imunologie   MeSH
• pankreatitida krev   imunologie   MeSH
• protilátky nádorové krev   imunologie   MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• specificita protilátek MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH

Refractory coeliac disease (RCD) is a very rare and dangerous form of CD, in which gluten-free diet loses its therapeutic effect and the damage of intestinal mucosa persists. Because of the adherence to the diet, serological markers of CD [immunoglobulin A (IgA) antibodies against gliadin, tissue transglutaminase (tTG) and endomysium] are often missing in RCD patients. We found substantially elevated levels of IgA anti-calreticulin (CRT) antibodies in the sera of almost all RCD patients tested. These sera were negative for IgA antibodies to gliadin and tTG and only some of them showed IgA antibodies to enterocytes. Analysis of patients' IgA reactivity to CRT fragments (quarters and halves) by Western blotting revealed differences in the specificity of IgA antibodies between RCD and CD patients. We therefore used the Pepscan technique with synthetic overlapping decapeptides of CRT to characterize antigenic epitopes recognized by serum IgA antibodies of RCD patients. Employing this method we demonstrated several dominant antigenic epitopes recognized by IgA antibodies of RCD patients on the CRT molecule. Epitope GVTKAAEKQMKD was recognized predominantly by serum IgA of RCD patients. Our results suggest that testing for serum IgA antibodies against CRT and its selected peptide could be a very useful tool in RCD differential diagnosis.

• MeSH
• bezlepková dieta škodlivé účinky   MeSH
• celiakie diagnóza   imunologie   krev   MeSH
• ELISA MeSH
• enterocyty chemie   imunologie   MeSH
• financování organizované MeSH
• gliadin imunologie   krev   MeSH
• imunoglobulin A imunologie   krev   MeSH
• kalretikulin imunologie   krev   MeSH
• lidé středního věku MeSH
• lidé MeSH
• protilátky anti-idiotypické imunologie   krev   MeSH
• senioři MeSH
• senzitivita a specificita MeSH
• transglutaminasy imunologie   krev   MeSH
• western blotting MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH

• MeSH
• autoprotilátky diagnostické užití   klasifikace   krev   MeSH
• biologické markery krev   MeSH
• celiakie imunologie   komplikace   krev   MeSH
• duševně nemocní MeSH
• financování organizované MeSH
• kalretikulin imunologie   MeSH
• lidé MeSH
• Check Tag
• lidé MeSH