Prognostic association of starvation-induced gene expression in head and neck cancer.

Autophagy-related genes (ARGs) have been implicated in the initiation and progression of malignant tumor promotion. To investigate the dynamics of expression of genes, including ARGs, head and neck squamous cell carcinoma (HNSCC) cells were placed under serum-free conditions to induce growth retardation and autophagy, and these starved cells were subjected to transcriptome analysis. Among the 21 starvation-induced genes (SIGs) located in the autophagy, cell proliferation, and survival signaling pathways, we identified SIGs that showed prominent up-regulation or down-regulation in vitro. These included AGR2, BST2, CALR, CD22, DDIT3, FOXA2, HSPA5, PIWIL4, PYCR1, SGK3, and TRIB3. The Cancer Genome Atlas (TCGA) database of HNSCC patients was used to examine the expression of up-regulated genes, and CALR, HSPA5, and TRIB3 were found to be highly expressed relative to solid normal tissue in cancer and the survival rate was reduced in patients with high expression. Protein-protein interaction analysis demonstrated the formation of a dense network of these genes. Cox regression analysis revealed that high expression of CALR, HSPA5, and TRIB3 was associated with poor prognosis in patients with TCGA-HNSCC. Therefore, these SIGs up-regulated under serum starvation may be molecular prognostic markers in HNSCC patients.

Biphasic Increases of Cell Surface Calreticulin Following Treatment with Mitoxantrone.

Calreticulin (CRT) and calnexin (CNX), homologous major chaperones in the endoplasmic reticulum (ER), are known to translocate to the cell surface in response to chemotherapeutic agents, such as mitoxantrone (MIT), and cellular stresses, including apoptosis. Cell surface CRT (ecto-CRT) is relevant to the phagocytic uptake of cancer cells and dying cells, and pre-apoptotic exposure of CRT has been reported to result in enhanced immunogenicity of dying tumor cells, serving as a damage-associated molecular pattern (DAMP). In this study, HT-29 cells were treated with MIT to induce ER stress, and ecto-CRT and cell surface CNX were quantified by flow cytometry in the absence or presence of caspase inhibitors, a calpain inhibitor, or a scavenger of reactive oxygen species. The biphasic (early transient and late sustained) increase of ecto-CRT on HT-29 cells was observed after treatment with MIT. We confirmed that the early increase in ecto-CRT after 4 h of MIT treatment was not related to apoptosis, whereas the increase of ecto-CRT, as well as that of cell-surface CNX, during the later stage of treatment was caspase dependent and related to apoptosis. In addition, our results suggested that the early peak of ecto-CRT was mediated by activation of caspase 8 by ER stress. Thus, the physiological significance of the late increases in cell-surface CRT and/or CNX might be considered an "eat-me signal" for the removal of dead cells by phagocytosis, while the early increase in ecto-CRT caused by ER stress might enhance the immunogenicity of stressed tumor cells.

Dispersal and molecular characterisation of the Echinococcus granulosus (Batsch, 1786) complex isolated from various intermediate hosts in the Calabria region, southern Italy.

Cystic echinococcosis (CE) is a zoonotic disease caused by the tapeworms of the Echinococcus granulosus sensu lato complex, which have worldwide distribution. No data on the circulation of genotypes of the E. granulosus complex in intermediate hosts in endemic areas in Calabria are available. The aims of our study were to evaluate the dispersal of genotypes of the E. granulosus complex in Calabria and to characterise parasite isolates by Sanger sequencing and phylogenetic analysis. We collected 71 animal samples from pigs, wild boars, sheep, cattle and goats. The first PCR screening analysis targeted three partial genomic regions: the cytochrome c oxidase subunit 1 (cox1), calreticulin protein (cal) and NADH dehydrogenase subunit 1 (nad1); this identified 28 parasitic cysts. Bidirectional sequencing of cox1 amplicons and phylogenetic analysis allowed us to characterise all isolates. Molecular analyses of 28 newly generated cox1 sequences revealed that most wild boars (n = 16) and three pigs were parasitised by the larval stage of Taenia hydatidena Pallas, 1766, called cysticercus tenuicollis. Two isolates from wild boars were identified as Echinococcus canadensis Webster and Cameron, 1961 (G7), while five sheep and two goats were infected with E. granulosus G1 (sheep strain) and G1 microvariant (previously reported as G2 genotype or Tasmanian sheep strain), respectively. These molecular findings should prompt further and more extensive studies, to elucidate regional transmission patterns and to guide control programs.

Quantitation of calreticulin exposure associated with immunogenic cell death.

Tumor cells treated by immunogenic cell death (ICD) inducers emit danger associated molecular patterns (DAMP), including but not limited to calreticulin (CALR), which translocates from the ER lumen to the surface of the cellular membrane where it serves as de novo uptake signal for antigen presenting cells of the immune system. CALR is exposed at an early stage of ICD and dictates tumor antigen transfer and therefore the immunogenicity of cancer cell death. Here, we provide a bi-color flow cytometry protocol for the quantification of ICD-associated CALR cell surface exposure in fixed samples. As compared to the detection of surface exposed CALR by confocal microscopy, the present flow cytometry-based analysis is cost-efficient and does not require sophisticated equipment. Moreover, the staining panel can be extended to a multicolor analysis for the parallel assessment of additional parameters.

Side-by-side comparison of flow cytometry and immunohistochemistry for detection of calreticulin exposure in the course of immunogenic cell death.

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.

The potentiated checkpoint blockade immunotherapy by ROS-responsive nanocarrier-mediated cascade chemo-photodynamic therapy.

Checkpoint inhibitors, such as anti-PD-1/PD-L1 antibodies, have been proven as a promising type of immunotherapy in a number of cancers, but the relatively low response rates limit their scope of clinical application. Here, we report the use of cascade chemo-photodynamic therapy (chemo-PDT) with reactive oxygen species (ROS)-sensitive lipid-polymer hybrid nanoparticles TKHNP-C/D to potentiate the antitumor efficacy of anti-PD-L1 antibody (aPD-L1). Under light irradiation, TKHNP-C/D not only induced photodynamic therapy (PDT) but also boosted intracellular DOX release via the rapid degradation of its hydrophobic core, promoting an efficient cascade of chemo-PDT to inhibit tumor growth by a single treatment. More importantly, the cascade chemo-PDT could evoke anticancer immune responses and efficiently synergize with aPD-L1 to generate an abscopal effect, which could simultaneously inhibit primary and distant tumor growth.

Cervical fluid calreticulin and cathepsin-G in pregnancies complicated by preterm prelabor rupture of membranes.

OBJECTIVE: The study aimed to determine the cervical calreticulin and cathepsin-G concentrations in pregnancies complicated by preterm prelabor rupture of membranes (PPROM) with respect to the presence of microbial invasion of the amniotic cavity (MIAC) and intra-amniotic inflammation (IAI). METHODS: Eighty women with singleton pregnancies complicated by PPROM were included in this study. Cervical and amniotic fluids were obtained at the time of admission, and concentrations of calreticulin and cathepsin-G in cervical fluid were determined using ELISA. The MIAC was defined as a positive PCR analysis for Ureaplasma species, Mycoplasma hominis, and/or Chlamydia trachomatis and/or by positivity for the 16S rRNA gene. IAI was defined as amniotic fluid bedside IL-6 concentrations ≥745 pg/mL Result: Neither women with MIAC nor with IAI had different cervical fluid concentrations of calreticulin (with MIAC: median 18.9 pg/mL vs. without MIAC: median 14.7 pg/mL, p = 0.28; with IAI: median 14.3 pg/mL vs. without IAI: median 15.6 pg/mL, p = 0.57;) or of cathepsin-G (with MIAC: median 30.7 pg/mL vs. without MIAC: median 24.7 pg/mL, p = 0.28; with IAI: median 27.3 pg/mL vs. without IAI: median 25.1 pg/mL, p = 0.80) than women without those complications. No associations between amniotic fluid IL-6 concentrations, gestational age at sampling, and cervical fluid calreticulin and cathepsin-G concentrations were found. CONCLUSIONS: Cervical fluid calreticulin and cathepsin-G concentrations did not reflect the presence of MIAC or IAI in women with PPROM.

Catestatin and vasostatin concentrations in healthy dogs.

BACKGROUND: The neuroendocrine glycoprotein chromogranin A is a useful biomarker in humans for neuroendocrine tumors and stress. Chromogranin A can be measured in both blood and saliva. The objective of this study was to investigate concentrations of and correlation between the chromogranin A epitopes catestatin and vasostatin in healthy dogs accustomed to the sample collection procedures. Blood and saliva samples were collected from 10 research Beagle dogs twice daily for 5 consecutive days, and from 33 privately-owned blood donor dogs in association with 50 different blood donation occasions. All dogs were familiar with sample collection procedures. During each sampling, stress behavior was scored by the same observer using a visual analog scale (VAS) and serum cortisol concentrations. Catestatin and vasostatin were analyzed using radioimmunoassays for dogs. RESULTS: The dogs showed minimal stress behavior during both saliva sampling and blood sampling as monitored by VAS scores and serum cortisol concentrations. Few and insufficient saliva volumes were obtained and therefore only catestatin could be analyzed. Catestatin concentrations differed significantly and did not correlate significantly with vasostatin concentrations (P < 0.0001). Age, gender, breed, and time of sample collection did not significantly affect concentrations of plasma catestatin, vasostatin, and saliva catestatin. CONCLUSIONS: The normal ranges of plasma catestatin (0.53-0.98 nmol/l), vasostatin (0.11-1.30 nmol/l), and saliva catestatin (0.31-1.03 nmol/l) concentrations in healthy dogs accustomed to the sampling procedures were determined. Separate interpretation of the different chromogranin A epitopes from either saliva or plasma is recommended.

Sublethal exposure to alpha radiation (223Ra dichloride) enhances various carcinomas' sensitivity to lysis by antigen-specific cytotoxic T lymphocytes through calreticulin-mediated immunogenic modulation.

Radium-223 dichloride (Xofigo®; 223Ra) is an alpha-emitting radiopharmaceutical FDA-approved for the treatment of bone metastases in patients with advanced castration-resistant prostate cancer. It is also being examined clinically in patients with breast and lung carcinoma and patients with multiple myeloma. As with other forms of radiation, the aim of 223Ra is to reduce tumor burden by directly killing tumor cells. External beam (photon) and proton radiation have been shown to augment tumor sensitivity to antigen-specific CD8+ cytotoxic T lymphocytes (CTLs). However, little is known about whether treatment with 223Ra can also induce such immunogenic modulation in tumor cells that survive irradiation. We examined these effects in vitro by exposing human prostate, breast, and lung carcinoma cells to sublethal doses of 223Ra. 223Ra significantly enhanced T cell-mediated lysis of each tumor type by CD8+ CTLs specific for MUC-1, brachyury, and CEA tumor antigens. Immunofluorescence analysis revealed that the increase in CTL killing was accompanied by augmented protein expression of MHC-I and calreticulin in each tumor type, molecules that are essential for efficient antigen presentation. Enhanced tumor-cell lysis was facilitated by calreticulin surface translocation following 223Ra exposure. The phenotypic changes observed after treatment appear to be mediated by induction of the endoplasmic reticulum stress response pathway. By rendering tumor cells more susceptible to T cell-mediated lysis, 223Ra may potentially be effective in combination with various immunotherapies, particularly cancer vaccines that are designed to generate and expand patients' endogenous antigen-specific T-cell populations against specific tumor antigens.

Amniotic fluid calreticulin in pregnancies complicated by the preterm prelabor rupture of membranes.

OBJECTIVE: This study aimed to determine the amniotic fluid calreticulin concentrations in women with the preterm prelabor rupture of membranes (PPROM) based on the microbial invasion of the amniotic cavity (MIAC), intraamniotic inflammation (IAI) and microbial-associated IAI. METHODS: One hundred sixty-eight women with singleton pregnancies were included in this study. Amniotic fluid samples were obtained by transabdominal amniocentesis and were assayed for calreticulin concentrations by ELISA. IAI was defined as an amniotic fluid interleukin-6 concentration > 745 pg/ml. Microbial-associated IAI was defined as the presence of both MIAC and IAI. RESULT: Women with MIAC (with MIAC: median 54.4 ng/ml, versus without MIAC: median 32.6 ng/ml; p < 0.0001), IAI (with IAI: median 66.8 ng/ml, versus without IAI: median 33.0 ng/ml; p < 0.0001) and microbial-associated IAI (with microbial-associated IAI: median 82.5 ng/ml, versus without microbial-associated IAI: median 33.7 ng/ml; p < 0.0001) had higher concentrations of calreticulin than women without these complications. An amniotic fluid calreticulin concentration of 81.4 ng/ml was found to be the best cutoff point for identifying women with microbial-associated IAI. CONCLUSIONS: The presence of microbial-associated IAI is associated with increased amniotic fluid calreticulin concentrations. Calreticulin seems to be a promising marker for the early identification of PPROM complicated by microbial-associated IAI.

A new monoclonal antibody (CAL2) detects CALRETICULIN mutations in formalin-fixed and paraffin-embedded bone marrow biopsies.

Recent advances in the diagnostic of myeloproliferative neoplasms (MPNs) discovered CALRETICULIN (CALR) mutations as a major driver in these disorders. In contrast to JAK2 mutations being mainly associated with polycythaemia vera, CALR mutations are only associated with primary myelofibrosis (PMF) and essential thrombocythaemia (ET). CALR mutations are present in the majority of PMF and ET patients lacking JAK2 and MPL mutations. As these CALR mutations are absent from reactive bone marrow (BM) lesions their presence indicates ET or PMF. So far these mutations are detectable only by molecular assays. Their molecular detection is cumbersome because of the great CALR mutation heterogeneity. Therefore, the availability of a simple assay would be of great help. All CALR mutations reported lead to a frameshift generating a new 36 amino-acid C-terminus. We generated a monoclonal antibody (CAL2) to this C-neoterminus by immunizing mice with a representative peptide and compared its performance with Sanger sequencing data in 173 MPNs and other BM diseases. There was a 100% correlation between the molecular and the CAL2 immunohistochemical (IHC) assays. Thus, the detection of CALR mutations by the CAL2 IHC is a specific, sensitive, rapid, simple and low-cost method.

Análise in situ de proteínas diferencialmente expressas em carcinomas epidermoides penianos por espectrometria de massas utilizando Matrix-Assisted Laser Desorption/Ionization (MALDI) / In situ analysis of protein differentially expressed in penile squamous cell carcinoma by Matrix-Assisted Laser Desorption/Ionization (MALDI) mass spectrometry

O carcinoma de pênis (CaPe) corresponde a uma doença maligna mutilante do homem. É mais frequente em regiões economicamente desprivilegiadas, como o Norte/Nordeste do Brasil, onde frequentemente é diagnosticado como doença mais avançada. Assim, novos marcadores diagnósticos, prognósticos e preditivos de tratamentos terapêuticos ainda são necessários. Abordagens proteômicas, incluindo o MALDI Imaging, podem contribuir neste sentido. Esta técnica emergente de espectrometria de massas permite a visualização da distribuição espacial de centenas de dados moleculares diretamente da superfície de uma secção tecidual, adquiridos por razão massa/carga (m/z). Neste contexto, nosso principal propósito foi integrar dados de proteômica clássica (gel 2D e Cromatografia Líquida acoplada à Espectrometria de Massas) e de MALDI Imaging, para obter padrões diferenciais de proteínas associados com amostras de Carcinoma Epidermoide Peniano usual (relacionado ou não ao HPV) e espécimes normais, a fim de buscar possíveis biomarcadores da doença. Um total de 45 amostras de CaPe, congeladas, foram inicialmente genotipadas para a presença do HPV. Destas, 60% foram positivas para variantes virais de alto risco. A proteômica clássica (N=24) evidenciou níveis diferenciais de 35 proteínas entre amostras de CaPe e controles, e 29 entre CaPe HPV positivo versus negativo (P<0,05; ANOVA). Redes de interações demonstraram que estes perfis proteicos interagiam com clusters de proteínas relacionadas com a carcinogênese e progressão tumoral. Entre eles, se destacaram aqueles formados por proteínas antioxidantes e de adesão celular, presentes em níveis elevados em tumores HPV negativos. A partir dos interactomas, quatro alvos proteicos foram selecionados para a análise in situ por imageamento: Calreticulina, 14-3-3 sigma, Serpina B5 e Glutationa-s-transferase. A aquisição de dados do MALDI Imaging foi conduzida após a digestão in situ pela tripsina, usando uma resolução de 200 µm e faixa de 700-3500 m/z para peptídeos (N=31). Os dados de identificação do gel 2D foram então integrados aos do imageamento. A identidade proteica dos filtros foi confirmada, in silico, por meio da presença de peptídeos teóricos co-localizados com o peptídeo experimental alvo nas secções de CaPe. Não houve associação significativa entre os parâmetros clinicopatológicos e as intensidades de sinal dos alvos (P>0,05, U de Mann-Whitney). Análises não supervisionadas, realizadas a partir dos dados do MALDI Imaging, evidenciaram mapas de segmentação que coindiciram com as regiões tumorais e margens adjacentes livres de neoplasia. Entre os principais valores de m/z diferenciadores estava o pico 1413 ± 2,5 Da, abundante nas regiões tumorais, e correlacionado ao peptídeo experimental m/z 1410,86 referente à proteína Calreticulina (CRT), o. Análises estatísticas (PCA e Curva ROC) indicaram este valor de m/z como potencial biomarcador da doença. Por conseguinte, a CRT foi selecionada para a etapa de validação por imunoistoquímica em tecidos parafinados de CaPe (N=158). Níveis elevados de imunoreatividade da CRT foram associados com piores tempo de sobrevida global (Razão de Risco 2,3; IC-1,46-3,96; P<0,001) e câncer específica (Razão de Risco 4,37; IC-1,66-11,51; P=0,002) nos casos de CaPe. A presença de metástase em linfonodos foi considerado um fator prognóstico independente para o risco de morte pelo câncer (Razão de Risco ­ 14,18; CI-3,29-61,12; P <0,001). A imunoreatividade da CRT também foi capaz de predizer a presença de metástase em linfonodos (Chance de Risco: 1,006; IC- 1,0001-1,0012; p=0,044). Estes dados, em conjunto, sugerem que a CRT pode ser um potencial biomarcador prognóstico do CaPe. A estratégia de integração da proteômica clássica com o MALDI Imaging, mostrou-se uma ferramenta útil na busca de novos biomarcadores para o CaPe. Além disto, o trabalho adicionou uma visão analítica à histopatologia clássica, o que deverá inserir as técnicas utilizadas neste projeto em estudos de Anatomia Patológica, tanto em nossa instituição, quanto no contexto global.

Penile cancer (PeCa) corresponds to a mutilating malignant disease in men. It is more frequent in underprivileged socioeconomic regions (e.g., Noth, North-East of Brazil), where it is frequently diagnosed in advanced stages. Thus, new markers are still needed for early diagnosis, prognosis and prediction of therapy. Proteomic approaches, including MALDI Imaging, could assist in this effort. This emerging spatially resolved mass spectrometric technique can obtain topographical distribution of hundreds of molecules directly from the tissue section surface, mensured by mass/charge ratio (m/z). In this context, our mainly propose was to integrate classic proteomic data (2D gel and Liquid Chromatograph coupled with Mass Spectrometry) with MALDI Imaging to obtain diferential patterns of protein associated with Usual Squamous Cell Penile Carcinoma (HPV related or not) and normal specimens, to look for possible biomarkers of the disease. A total of 45 fresh-frozen PeCa samples were initially searched for HPV genotype, 60% of which were positive for high-risk HPV. Classic proteomics (N=24) demonstrated diferential levels of 35 proteins comparing PeCa and control samples, and 29 comparing HPV-positive versus HPV-negative PeCa samples (P<0.05; ANOVA). Protein networks showed that these protein profiles interact with clusters of proteins related with tumorigenesis and tumor progression processes. Among them, antioxidant and cell adhesion proteins play a critical role in HPV negative penile tumors. Based on interactome data, four protein targets were selected for in situ analyses by imaging: Calreticulin, 14-3-3 protein sigma, Serpin B5 and Glutatione-s-transferase. MALDI Imaging data acquisition of peptides was conducted after in situ trypsin digestion using a lateral resolution of 200 µm, covering the range 700- 3500 m/z (N=31). After that, 2D gel based proteomic data was integrated with Imaging data. The filter protein identities were confirmed in silico by the co-localization of theoretical triptic peptides with the experimental peptides in PeCa sections. There was no significant association between the clinical and pathological parameters and the target signal intensities (P>0.05; U de Mann-Whitney). An unsupervised clustering analysis based on MALDI Imaging data reveled segmentation maps that coincide with histological annotation for tumor and adjacent non-neoplasic regions. Among the mainly differentiating m/z values there was 1413 ± 2.5 Da. This peak was especially co-localized with tumoral regions and correlated with Calreticulin (CRT) experimental peptide (m/z 1410,86). Statistical analysis (PCA and ROC Curves) indicated this m/z value as a potencial biomarker of the disease. For this reason, CRT was selected for validation by immunohistochemistry performed on paraffin-embedded PeCa tissues (N=158). As result, CRT hiperexpression in PeCa tissue increased the risk of unfavorable overall survival (Relative Risk ­ 2.3; CI-1.46-3.96; P<0.001) and cancer specific survival (Relative Risk ­ 4.37; CI-1.66-11.51; P=0.002) in these patients. Lymph node metastasis represented an independent prognostic risk factor for death related to cancer in our patients (Relative risk ­ 14.18; CI-3.29-61.12; P <0.001). CRT immunoreactivity was also capable to predict the presence of lymph node metastases (Risk Chance ­ 1,006; CI-1.0001-1.00123; P =0.044). Taken together, our results sugest that CRT may represent a prognostic biomarker of PeCa. The strategy of integrated classic proteomic and MALDI Imaging revealed as usefull tool to search for news biomarkers of the disease. Futhermore, this work added an analytical perspective to the classical histopathology, allowing to include the techniques used in this project in future morphological studies, both in our institution and in the global context.

Calreticulin mRNA expression and clinicopathological characteristics in acute myeloid leukemia.

Calreticulin, encoded by CALR, is a multifunctional protein with roles in calcium homeostasis and chaperoning molecular processes. This study aimed to evaluate calreticulin mRNA expression levels in acute myeloid leukemia (AML) compared with other hematologic malignancies, and to investigate the clinicopathological characteristics associated with expression in AML patients. The study group included 43 patients diagnosed with AML, 57 with other hematologic malignancies, and 21 benign hematologic conditions. CALR mRNA quantification using real-time polymerase chain reaction revealed it to be significantly higher in AML compared with other hematologic malignancies (P < 0.0001). There was no difference in CALR mRNA expression between AML subgroups by karyotype (P = 0.3201). No differences were found in age, white blood cell counts, platelet counts, bone marrow blast percentage, calcium, lactate dehydrogenase or CD34 expression rate between the high and low CALR groups (CALR mRNA ≥ 1.2 fold and <1.2 fold, respectively), although hemoglobin and sex differences were observed. Although statistically not significant, there was a trend that Relapse rate was lower (54.5% vs. 84.6%) (P = 0.1063) and disease-free survival was longer (22 months vs. 7 months) (P = 0.0784) in low CALR group, whereas overall survival was similar between the two groups (11 months and 8 months). The clinical relevance of CALR expression in AML remains to be clarified in a larger cohort.

Entamoeba invadens: Identification of a SERCA protein and effect of SERCA inhibitors on encystation.

Calcium has an important role on signaling of different cellular processes, including growth and differentiation. Signaling by calcium also has an essential function in pathogenesis and differentiation of the protozoan parasites Entamoeba histolytica and Entamoeba invadens. However, the proteins of these parasites that regulate the cytoplasmic concentration of this ion are poorly studied. In eukaryotic cells, the calcium-ATPase of the SERCA type plays an important role in calcium homeostasis by catalyzing the active efflux of calcium from cytoplasm to endoplasmic reticulum. Here, we reported the identification of SERCA of E. invadens (EiSERCA). This protein contains a putative sequence for endoplasmic reticulum retention and all domains involved in calcium transport identified in mammalian SERCA. By immunofluorescence assays, an antibody against SERCA of E. histolytica detected EiSERCA in a vesicular network in the cytoplasm of E. invadens trophozoites, co-localizing with calreticulin. Interestingly, EiSERCA was redistributed close to plasma membrane during encystation, suggesting that this pump could participate in regulate the calcium concentration during this process. In addition, thapsigargin and cyclopiazonic acid, both specific inhibitors of SERCA, affected the number and structure of cysts, supporting the hypothesis that calcium flux mediated by SERCA has an important role in the life cycle of Entamoeba.

Cloning and characterization of calreticulin and its association with salinity stress in P. trituberculatus.

Calreticulin (CRT) is a highly conserved and multifunctional endoplasmic reticulum (ER) chaperone protein and plays important roles in salinity stress response. Portunus trituberculatus is a commercially important fishery species, and water salinity conditions influence its commercial farming significantly. In order to research the function of calreticulin under salinity stress, the full-length cDNA sequence of calreticulin from P. trituberculatus (PtCRT) was firstly cloned and characterized. The complete cDNA sequence of PtCRT is 1676 bp with 1218 bp open reading frame (ORF), encoding a polypeptide of 405 amino acids. Multiple sequence alignments showed that the deduced acid amino sequences of PtCRT shared the highest homology to CRT of Fenneropenaeus chinensis (89%). Fluorescent quantitative real-time PCR analysis indicated that PtCRT was expressed in all detected tissues and showed the highest expression level in hepatopancreas. In addition, salinity challenge significantly influenced the expression level of PtCRT in gill. Six single nucleotide polymorphisms (SNPs) were detected in cDNA sequence of PtCRT, and one SNP was associated with the salt tolerant trait. All results indicated that PtCRT plays an important role in mediating the salinity adaption of P. trituberculatus.

Calreticulin mutation-specific immunostaining in myeloproliferative neoplasms: pathogenetic insight and diagnostic value.

Mutations in the gene calreticulin (CALR) occur in the majority of JAK2- and MPL-unmutated patients with essential thrombocythemia (ET) and primary myelofibrosis (PMF); identifying CALR mutations contributes to the diagnostic pathway of ET and PMF. CALR mutations are heterogeneous spanning over the exon 9, but all result in a novel common protein C terminus. We developed a polyclonal antibody against a 17-amino-acid peptide derived from mutated calreticulin that was used for immunostaining of bone marrow biopsies. We show that this antibody specifically recognized patients harboring different types of CALR mutation with no staining in healthy controls and JAK2- or MPL-mutated ET and PMF. The labeling was mostly localized in megakaryocytes, whereas myeloid and erythroid cells showed faint staining, suggesting a preferential expression of calreticulin in megakaryocytes. Megakaryocytic-restricted expression of calreticulin was also demonstrated using an antibody against wild-type calreticulin and by measuring the levels of calreticulin RNA by gene expression analysis. Immunostaining using an antibody specific for mutated calreticulin may become a rapid, simple and cost-effective method for identifying CALR-mutated patients complementing molecular analysis; furthermore, the labeling pattern supports the preferential expansion of megakaryocytic cell lineage as a result of CALR mutation in an immature hematopoietic stem cell.

Somatic CALR mutations in myeloproliferative neoplasms with nonmutated JAK2.

BACKGROUND: Somatic mutations in the Janus kinase 2 gene (JAK2) occur in many myeloproliferative neoplasms, but the molecular pathogenesis of myeloproliferative neoplasms with nonmutated JAK2 is obscure, and the diagnosis of these neoplasms remains a challenge. METHODS: We performed exome sequencing of samples obtained from 151 patients with myeloproliferative neoplasms. The mutation status of the gene encoding calreticulin (CALR) was assessed in an additional 1345 hematologic cancers, 1517 other cancers, and 550 controls. We established phylogenetic trees using hematopoietic colonies. We assessed calreticulin subcellular localization using immunofluorescence and flow cytometry. RESULTS: Exome sequencing identified 1498 mutations in 151 patients, with medians of 6.5, 6.5, and 13.0 mutations per patient in samples of polycythemia vera, essential thrombocythemia, and myelofibrosis, respectively. Somatic CALR mutations were found in 70 to 84% of samples of myeloproliferative neoplasms with nonmutated JAK2, in 8% of myelodysplasia samples, in occasional samples of other myeloid cancers, and in none of the other cancers. A total of 148 CALR mutations were identified with 19 distinct variants. Mutations were located in exon 9 and generated a +1 base-pair frameshift, which would result in a mutant protein with a novel C-terminal. Mutant calreticulin was observed in the endoplasmic reticulum without increased cell-surface or Golgi accumulation. Patients with myeloproliferative neoplasms carrying CALR mutations presented with higher platelet counts and lower hemoglobin levels than patients with mutated JAK2. Mutation of CALR was detected in hematopoietic stem and progenitor cells. Clonal analyses showed CALR mutations in the earliest phylogenetic node, a finding consistent with its role as an initiating mutation in some patients. CONCLUSIONS: Somatic mutations in the endoplasmic reticulum chaperone CALR were found in a majority of patients with myeloproliferative neoplasms with nonmutated JAK2. (Funded by the Kay Kendall Leukaemia Fund and others.).

A comparative proteomic study identified calreticulin and prohibitin up-regulated in adrenocortical carcinomas.

BACKGROUND: Identifying novel tumor biomarkers to develop more effective diagnostic and therapeutic strategies for patients with ACC is urgently needed. The aim of the study was to compare the proteomic profiles between adrenocortical carcinomas (ACC) and normal adrenocortical tissues in order to identify novel potential biomarkers for ACC. METHODS: The protein samples from 12 ACC tissues and their paired adjacent normal adrenocortical tissues were profiled with two-dimensional electrophoresis; and differentially expressed proteins were identified by mass spectrometry. Expression patterns of three differently expressed proteins calreticulin, prohibitin and HSP60 in ACC, adrenocortical adenomas (ACA) and normal adrenocortical tissues were further validated by immunohistochemistry. RESULTS: In our proteomic study, we identified 20 up-regulated and 9 down-regulated proteins in ACC tissues compared with paired normal controls. Most of the up-regulated proteins were focused in protein binding and oxidoreductase activity in Gene Ontology (GO) molecular function classification. By immunohistochemistry, two biomarkers calreticulin and prohibitin were validated to be overexpressed in ACC compared with adrenocortical adenomas (ACA) and normal tissues, but also calreticulin overexpression was significantly associated with tumor stages of ACC. CONCLUSION: For the first time, calreticulin and prohibitin were identified to be novel candidate biomarkers for ACC, and their roles during ACC carcinogenesis and clinical significance deserves further investigation. VIRTUAL SLIDES: The virtual slides for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1897372598927465.

Chemotherapy-induced immunogenic modulation of tumor cells enhances killing by cytotoxic T lymphocytes and is distinct from immunogenic cell death.

Certain chemotherapeutic regimens trigger cancer cell death while inducing dendritic cell maturation and subsequent immune responses. However, chemotherapy-induced immunogenic cell death (ICD) has thus far been restricted to select agents. In contrast, several chemotherapeutic drugs modulate antitumor immune responses, despite not inducing classic ICD. In addition, in many cases tumor cells do not die after treatment. Here, using docetaxel, one of the most widely used cancer chemotherapeutic agents, as a model, we examined phenotypic and functional consequences of tumor cells that do not die from ICD. Docetaxel treatment of tumor cells did not induce ATP or high-mobility group box 1 (HMGB1) secretion, or cell death. However, calreticulin (CRT) exposure was observed in all cell lines examined after chemotherapy treatment. Killing by carcinoembryonic antigen (CEA), MUC-1, or PSA-specific CD8(+) CTLs was significantly enhanced after docetaxel treatment. This killing was associated with increases in components of antigen-processing machinery, and mediated largely by CRT membrane translocation, as determined by functional knockdown of CRT, PERK, or CRT-blocking peptide. A docetaxel-resistant cell line was selected (MDR-1(+), CD133(+)) by continuous exposure to docetaxel. These cells, while resistant to direct cytostatic effects of docetaxel, were not resistant to the chemomodulatory effects that resulted in enhancement of CTL killing. Here, we provide an operational definition of "immunogenic modulation," where exposure of tumor cells to nonlethal/sublethal doses of chemotherapy alters tumor phenotype to render the tumor more sensitive to CTL killing. These observations are distinct and complementary to ICD and highlight a mechanism whereby chemotherapy can be used in combination with immunotherapy.