Calreticulin Research Articles

Disulfide bond-rich Nano-Silica for High-Efficiency cancer immunotherapy using synergistic endoplasmic reticulum stress cooperated mitochondrial dysfunction

In emerging cancer immunotherapy, the effectiveness of T lymphocytes is primarily hindered by elevated programmed cell death 1 ligand 1 (PD-L1) expression; simultaneously, the shift of tumor-associated macrophages (TAMs) towards tumorigenic M2-type macrophages further abrogates the efficacy of immunotherapy. Accordingly, we rationally designed a glutathione (GSH) responsive disulfide bond-rich nano-silica (DLC-HA) capable of efficient T cells infiltrating and TAMs re-polarization by encapsulating an endoplasmic reticulum (ER)-targeted photodynamic agent p-Ce6 and the glycolysis inhibitor lonidamine (LND), which works together to provoke ER stress and mitochondrial dysfunction. On the one hand, ER stress causes PD-L1 down-expression through ER-associated degradation (ERAD), while also stimulating the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) signaling pathway. Meanwhile, LND alters mitochondrial dysfunction and activates the AMPK energy pathway, enhancing ER stress and facilitating PD-L1 degradation. On the other hand, ER stress upregulates calreticulin (CRT) expression and mitochondrial dysfunction alleviates hypoxia to downregulate TAMs inhibitory receptor CD47, all of which effectively promotes the phagocytosis and re-polarization of TAMs to anti-tumorigenic M1-type. As expected, this nanoplatform approach, not only activates the immune response of T cells but also facilitates the re-polarization of TAMs in vitro and in vivo assays, offering a novel strategy for efficient cancer immunotherapy using ER stress cooperated mitochondrial dysfunction.

Top-down Proteomics for the Characterization and Quantification of Calreticulin Arginylation.

Arginylation installed by arginyltransferase 1 (ATE1) features an addition of arginine (Arg) to the reactive amino acids (e.g., Glu and Asp) at the protein N-terminus or side chain. Systemic removal of arginylation after ATE1 knockout (KO) in mouse models resulted in heart defects leading to embryonic lethality. The biological importance of arginylation has motivated the discovery of arginylation sites on proteins using bottom-up approaches. While bottom-up proteomics is powerful in localizing peptide arginylation, it lacks the ability to quantify proteoforms at the protein level. Here we developed a top-down proteomics workflow for characterizing and quantifying calreticulin (CALR) arginylation. To generate fully arginylated CALR (R-CALR), we have inserted an R residue after the signaling peptide (AA1-17). Upon overexpression in ATE1 KO cells, CALR and R-CALR were purified by affinity purification and analyzed by LCMS in positive mode. Both proteoforms showed charge states ranging from 27-68 with charge 58 as the most intense charge state. Their MS2 spectra from electron-activated dissociation (EAD) showed preferential fragmentation at the protein N-terminals which yielded sufficient c ions facilitating precise localization of the arginylation sites. The calcium-binding domain (CBD) gave minimum characteristic ions possibly due to the abundant presence of >100 D and E residues. Ultraviolet photodissociation (UVPD) compared with EAD and ETD significantly improved the sequence coverage of CBD. This method can identify and quantify CALR arginylation at absence, endogenous (low), and high levels. To our knowledge, our work is the first application of top-down proteomics in characterizing post-translational arginylation in vitro and in vivo.

Evaluation of Philadelphia-negative myeloproliferative neoplasms in Erbil Iraq; analysis of JAK 2, CALR, and MPL mutations

Introduction: The prevalence of Janus kinase 2 V617F, Jak 2-Exon12, calreticulin (CALR) gene mutations and myeloproliferative leukemia mutations in myeloproliferative neoplasms (MPNs) without BCR-ABL1 gene fusion rearrangement in Iraq remains unknown due to inadequate data. Objectives: The aim of this study was to ascertain the prevalence of these mutations and assess the clinical characteristics of polycythemia vera (PV), essential thrombocythemia (ET) and primary myelofibrosis (PMF) in Erbil, Iraq. Patients and Methods: In this cross-sectional study, 80 patients were evaluated for the presence of JAK 2 V617, CALR, and MPL mutations. Specific primers were utilized to amplify MPNs-associated mutations (JAK 2 V617F, Jak 2 -Exon12, CALR, and MPL) using DNA extracted from whole blood. Results: The presence of the JAK 2 V617F mutation was identified in 96% of patients diagnosed with PV and 35% of patients diagnosed with ET. Additionally, JAK 2 exon 12 was detected in 4% of PV patients. CALR mutation was identified in 65% of ET patients. No detection of MPL mutation was observed. A higher prevalence of the CALR mutation was observed in younger age groups, whereas the JAK 2 V617F mutation was predominantly found in older age groups. Conclusion: The incorporation of genetic tests for JAK 2 V617F, JAK 2 exon 12, MPL exon 10, and CALR exon 9 significantly improves the diagnostic effectiveness for BCR ABL1-gene fusion negative MPNs.

The investigation of janus kinase 2 and calreticulin mutations in patients with essential thrombocytosis

Aims: The aims of this study were to investigate the frequency of Janus Kinase 2 (JAK2) and calreticulin (CALR) mutations in patients with essential thrombocytosis (ET) and primary myelofibrosis (PMF) and to compare the data of each group with JAK2 and CALR mutations (+) and (-). Methods: The research group consisted of 80 patients with chronic myeloproliferative disease (CMPD) followed in Gazi University Hospital of Medical Faculty, Hematology Clinic. Results: Of the patients included in the study, 66.2% had ET and 33.8% had PMF. JAK2 mutation (+) was detected in 60% and CALR mutation (+) was found in 22.5% of the patients. JAK2 mutation (+) was detected in 60.4% of patients with ET and 59.3% of patients with PMF. In JAK2 (-) patients, CALR was detected as (+) in 11 patients (52.4%) with ET and 7 patients (63.6%) with PMF. Conclusion: Studies in the literature have shown that the incidence of CALR mutations in patients with CMPD is between 28% and 80% and that the mutation is mostly seen in patients with ET. As a result of our study, it was concluded that the laboratory findings of patients with CALR mutations (+) were similar to those in the literature and were more common in women and ET patients.

Risk Prediction and Risk Factors of Thrombotic/Bleeding Events in Patients with Myeloproliferative Neoplasm

To analyze the clinical characteristics and occurrence of thrombotic/bleeding events of patients with myeloproliferative neoplasm (MPN), and explore the main influencing factors, and create a risk prediction. The clinical data of 126 MPN patients with BCR-ABL fusion gene negative in the Department of Hematology of Gansu Provincial Hospital from January 2016 to September 2021 were collected, and their clinical characteristics, occurrence of thrombotic/bleeding events and main influencing factors were analyzed and summarized retrospectively. Then, a risk prediction model for thrombotic/bleeding events in MPN patients was constructed. Among 126 MPN patients, 50 patients (39.7%) had experienced thrombotic/bleeding events, including 44 patients (34.9%) with thrombotic events and 6 patients (4.8%) with bleeding events. Among thrombotic diseases, cerebral thrombosis was the most common (23/44, 52.3%), followed by 9 cases of limb artery thrombosis mainly characterized by finger and toe tip artery ischemia, occlusion and gangrene (9/44, 20.5%). Bleeding events included intracerebral hemorrhage and gastrointestinal hemorrhage. Univariate analysis showed that hypertension, hyperhomocysteinemia, white blood cell (WBC) ≥10×109/L, hematocrit (HCT) ≥49%, platelet (PLT) ≥600×109/L and JAK2V617F gene mutation were risk factors for thrombotic/bleeding events in MPN patients, while CALR gene mutation was a protective factor. Multivariate analysis showed that hypertension and PLT≥600×109/L were independent risk factors for thrombotic/bleeding events in MPN patients. The goodness of fit of the constructed risk prediction model was 0.872, and the area under the ROC curve was 0.838. The model was validated with clinical data, the sensitivity, specificity and accuracy was 78.85%, 87.83% and 84.13%, respectively . The risk of thrombotic/bleeding events in MPN patients with high WBC count, hypertension and hyperhomocysteinemia is higher. Controlling hypertension and hyperhomocysteinemia and reducing WBC and PLT counts are helpful to prevent thrombotic/bleeding events and improve the life quality of patients.

A genome-wide CRISPR/Cas9 screen identifies calreticulin as a selective repressor of ATF6α.

Activating transcription factor 6 (ATF6) is one of three endoplasmic reticulum (ER) transmembrane stress sensors that mediate the unfolded protein response (UPR). Despite its crucial role in long-term ER stress adaptation, regulation of ATF6 alpha (α) signalling remains poorly understood, possibly because its activation involves ER-to-Golgi and nuclear trafficking. Here, we generated an ATF6α/Inositol-requiring kinase 1 (IRE1) dual UPR reporter CHO-K1 cell line and performed an unbiased genome-wide CRISPR/Cas9 mutagenesis screen to systematically profile genetic factors that specifically contribute to ATF6α signalling in the presence and absence of ER stress. The screen identified both anticipated and new candidate genes that regulate ATF6α activation. Among these, calreticulin (CRT), a key ER luminal chaperone, selectively repressed ATF6α signalling: Cells lacking CRT constitutively activated a BiP::sfGFP ATF6α-dependent reporter, had higher BiP levels and an increased rate of trafficking and processing of ATF6α. Purified CRT interacted with the luminal domain of ATF6α in vitro and the two proteins co-immunoprecipitated from cell lysates. CRT depletion exposed a negative feedback loop implicating ATF6α in repressing IRE1 activity basally and overexpression of CRT reversed this repression. Our findings indicate that CRT, beyond its known role as a chaperone, also serves as an ER repressor of ATF6α to selectively regulate one arm of the UPR.

Calreticulin-Enigmatic Discovery.

Calreticulin (CRT) is an intrinsically disordered multifunctional protein that plays essential roles intra-and extra-cellularly. The Michalak laboratory has proposed that CRT was initially identified in 1974 by the MacLennan laboratory as the high-affinity Ca2+-binding protein (HACBP) of the sarcoplasmic reticulin (SR). This widely accepted belief has been ingrained in the scientific literature but has never been rigorously tested. In our report, we have undertaken a comprehensive reexamination of this assumption by meticulously examining the majority of published studies that present a proteomic analysis of the SR. These analyses have utilized proteomic analysis of purified SR preparations or purified components of the SR, namely the longitudinal tubules and junctional terminal cisternae. These studies have consistently failed to detect the HACBP or CRT in skeletal muscle SR. We propose that the existence of the HACBP has failed the test of reproducibility and should be retired to the annals of antiquity. Therefore, the scientific dogma that the HACBP and CRT are identical proteins is a non sequitur.

Benzothiazole‐Piperazine Hybrids Effectively Target C4‐2 Castration‐Resistant Prostate Cancer Cells in vitro Implicated through Computational Studies

AbstractA series of new analogs based on benzothiazole‐piperazine conjugates were synthesized and assessed to investigate their anticancer properties using in vitro and in silico techniques. The compounds 3 a–3 h were tested against prostate (C4‐2) cancer cells, and the results revealed that all the compounds showed significant inhibitory activity against C4‐2 cells (>50 % inhibition at 20 μM). Among all, 2‐(4‐(pyrimidin‐2‐yl) piperazin‐1‐yl) benzo[d]thiazole demonstrated the most prominent activity in the cell viability assay conducted displaying an IC50 value of 19.98 μM. In vitro studies have demonstrated that the compound can selectively target the androgen receptor (AR) and reduce the expression of several androgen‐responsive genes, including EAF2, ELL2, PSA and CALR genes, in castration‐resistant prostate cancer cells. Molecular docking results also revealed that all the compounds exhibited good energy binding scores against the androgen receptor target (PB ID: 2PNU) particularly compound 3 g which showed a maximum binding energy of −9.87 kcal/mol followed by other compounds as well as the established prostate cancer drug, enzalutamide, with a binding energy of −5.66 kcal/mol. Docking results were further supported by MD simulation studies, which confirmed that the ligand+protein complex was in stable conformation throughout the simulation time of 100 nanoseconds. Collectively, the present results, stemming from a combination of in vitro and in silico examinations, demonstrate that compound 3 g displays notable anti‐cancer characteristics, implying its viability as a prospective anti‐cancer pharmaceutical subject to clinical validation and subsequent development.

Paradoxical cell targeting of calreticulin-empowered, protein-only nanoparticles

Surface-exposed calreticulin (CRT) serves as a crucial cell damage-associated molecular pattern for immunogenic apoptosis, by generating an “eat me” signal to macrophages. Aiming at precision immunotherapies we intended to artificially label tumoral cells in vivo with a recombinant CRT, in a targeted way. For that, we have constructed a CRT fusion protein intended to surface attach CXCR4+ cancer cells, to stimulate their immunological destruction. As a targeting ligand of the CRT construct and to drive its specific cell adhesion, we used the peptide V1, a derivative of the vMIP-II cytokine and an antagonist of CXCR4. The modular protein tends to self-assemble as regular 16 nm nanoparticles, assisted by ionic Zn. Through both in vivo and in vitro experiments, we have determined that CRT itself confers cell targeting capabilities to the construct overcoming those of V1, that are only moderate. In particular, CRT binds HeLa cells in absence of further internalization, by a route fully independent of CXCR4. Furthermore, by cytometry in THP-1 cells, we observed that the binding of the protein is preferential for dead cells over live cells, a fact that cannot be associated to a mere artefactual adsorption. These data are discussed in the context of the oligomerizing properties of CRT and the potential clinical applicability of proteins and protein materials functionalized with this novel cell surface ligand.

Myeloproliferative Neoplasms Transcriptome Reveals Pro-Inflammatory Signature and Enrichment in Peripheral Blood Monocyte-Related Genes

Myeloproliferative neoplasms (MPN) are hematological diseases associated with genetic driver mutations in the JAK2, CALR, and MPL genes and exacerbated oncoinflammatory status. Analyzing public microarray data from polycythemia vera (n = 41), essential thrombocythemia (n = 21), and primary myelofibrosis (n = 9) patients’ peripheral blood by in silico approaches, we found that pro-inflammatory and monocyte-related genes were differentially expressed in MPN patients’ transcriptome. Genes related to cell activation, secretion of pro-inflammatory and pro-angiogenic mediators, activation of neutrophils and platelets, coagulation, and interferon pathway were upregulated in monocytes compared to controls. Together, our results suggest that molecular alterations in monocytes may contribute to oncoinflammation in MPN.

Initiating-clone analysis in patients with acute myeloid leukemia secondary to essential thrombocythemia

Most of essential thrombocythemia (ET) patients have the clone harboring a mutation in one of the JAK2, CALR, or MPL gene, and these clones generally acquire additional mutations at transformation to acute myeloid leukemia (AML). However, the proliferation of triple-negative clones has sometimes been observed at AML transformation. To clarify the clonal evolution of ET to AML, we analyzed paired samples at ET and AML transformation in eight patients. We identified that JAK2-unmutated AML clones proliferated at AML transformation in three patients in whom the JAK2-mutated clone was dominant at ET. In two patients, TET2-mutated, but not JAK2-mutated, clones might be common initiating clones for ET and transformed AML. In a patient with JAK2-mutated ET, SMARCC2, UBR4, and ZNF143, but not JAK2, -mutated clones proliferated at AML transformation. Precise analysis using single-cell sorted CD34+/CD38- fractions suggested that ET clone with JAK2-mutated and AML clone with TP53 mutation was derived from the common clone with these mutations. Although further study is required to clarify the biological significance of SMARCC2, UBR4, and ZNF143 mutations during disease progression of ET and AML transformation, the present results demonstrate the possibility of a common initial clone involved in both ET and transformed AML.

Blood Brain Barrier-Crossing Delivery of Felodipine Nanodrug Ameliorates Anxiety-Like Behavior and Cognitive Impairment in Alzheimer's Disease.

Alzheimer's disease (AD) is the most common age-related neurodegenerative disorder leading to cognitive decline. Excessive cytosolic calcium (Ca2+) accumulation plays a critical role in the pathogenesis of AD since it activates the NOD-like receptor family, pyrin domain containing 3 (NLRP3), switches the endoplasmic reticulum (ER) unfolded protein response (UPR) toward proapoptotic signaling and promotes Aβ seeding. Herein, a liposomal nanodrug (felodipine@LND) is developed incorporating a calcium channel antagonist felodipine for Alzheimer's disease treatment through a low-intensity pulse ultrasound (LIPUS) irradiation-assisted blood brain barrier (BBB)-crossing drug delivery. The multifunctional felodipine@LND is effectively delivered to diseased brain through applying a LIPUS irradiation to the skull, which resulted in a series of positive effects against AD. Markedly, the nanodrug treatment switched the ER UPR toward antioxidant signaling, prevented the surface translocation of ER calreticulin (CALR) in microglia, and inhibited the NLRP3 activation and Aβ seeding. In addition, it promoted the degradation of damaged mitochondria via mitophagy, thereby inhibiting the neuronal apoptosis. Therefore, the anxiety-like behavior and cognitive impairment of 5xFAD mice with AD is significantly ameliorated, which manifested the potential of LIPUS - assisted BBB-crossing delivery of felodipine@LND to serve as a paradigm for AD therapy based on the well-recognized clinically available felodipine.

Recombinant Ixodes scapularis Calreticulin Binds Complement Proteins but Does Not Protect Borrelia burgdorferi from Complement Killing.

Ixodes scapularis is a blood-feeding obligate ectoparasite responsible for transmitting the Lyme disease (LD) agent, Borrelia burgdorferi. During the feeding process, I. scapularis injects B. burgdorferi into the host along with its saliva, facilitating the transmission and colonization of the LD agent. Tick calreticulin (CRT) is one of the earliest tick saliva proteins identified and is currently utilized as a biomarker for tick bites. Our recent findings revealed elevated levels of CRT in the saliva proteome of B. burgdorferi-infected I. scapularis nymphs compared to uninfected ticks. Differential precipitation of proteins (DiffPOP) and LC-MS/MS analyses were used to identify the interactions between Ixs (I. scapularis) CRT and human plasma proteins and further explore its potential role in shielding B. burgdorferi from complement killing. We observed that although yeast-expressed recombinant (r) IxsCRT binds to the C1 complex (C1q, C1r, and C1s), the activator of complement via the classical cascade, it did not inhibit the deposition of the membrane attack complex (MAC) via the classical pathway. Intriguingly, rIxsCRT binds intermediate complement proteins (C3, C5, and C9) and reduces MAC deposition through the lectin pathway. Despite the inhibition of MAC deposition in the lectin pathway, rIxsCRT did not protect a serum-sensitive B. burgdorferi strain (B314/pBBE22Luc) from complement-induced killing. As B. burgdorferi establishes a local dermal infection before disseminating to secondary organs, it is noteworthy that rIxsCRT promotes the replication of B. burgdorferi in culture. We hypothesize that rIxsCRT may contribute to the transmission and/or host colonization of B. burgdorferi by acting as a decoy activator of complement and by fostering B. burgdorferi replication at the transmission site.

P-187 Profiling secreted proteins in human embryos: Time-specific discrimination of ploidy and confirmation of enhanced post-implantation development with maternal co-culture

Abstract Study question Can proteins released by embryos into culture medium between 7- and 14-days post-fertilization (d.p.f.) potentially function as biomarkers indicating the ploidy status of the embryos? Summary answer Combined secreted levels of calreticulin (CALR), human Placental Lactogen (hPL), Placental Growth Factor (PlGF) and human Pappalysin-1 (PAPP-A) differentiate euploid from chromosome 21-aneuploid embryos. What is known already Exploring post-implantation embryo development is vital due to potential errors impacting early pregnancy or postnatal health during this period. Trisomy 21 (T21) is a common aneuploidy that can lead to live births but with postnatal health concerns, while chromosome 21 monosomy (M21) often results in embryo developmental arrest. Understanding post-implantation development and secreted products into human post-implantation niche is crucial for unraveling embryo-maternal interactions. Building on prior studies indicating ploidy-related gene and metabolite expression in pre-implantation embryos (DOI:10.1016/j.fertnstert.2019.01.023), this study aims to assess variations in the secretome of embryos with different ploidy during post-implantation development. Study design, size, duration Comparative study involving 48 science-donated human 6 d.p.f. blastocysts initiating hatching coming from in-vitro fertilization cycles. Preimplantation genetic testing identified Euploid (n = 20), pure T21 (n = 14), and pure M21 (n = 14) embryos. Two extended in-vitro culture protocols were compared: co-culturing of human embryos in a 3D system with endometrial cells or in a culture medium designed for post-implantation development but lacking maternal cells. Participants/materials, setting, methods Euploid, T21 and M21 blastocysts were thawed and cultured in-vitro until 14 d.p.f. in both culture systems described above. Levels of CALR, hPL, PlGF and PAPP-A in conditioned embryo media were quantified by ELISA immunoassays at 7, 10, 12 and 14 d.p.f. Absolute secreted protein concentrations (ng/mL) in each case were compared by two-way ANOVA followed by Tukey’s test for multiple comparisons. P < 0.05 was consider as statistically significant. Main results and the role of chance In both culture systems tested, at 7 d.p.f. secreted CALR, hPL and PlGF by M21 embryos were diminished when compared to euploid embryos (p < 0.01). At 10 d.p.f., euploid embryos displayed a significant increase in secreted PAPP-A, surpassing levels in T21 (p < 0.05) and M21 embryos (p < 0.01). Embryo co-culture in 3D endometrial systems led to progressive increase in secreted PAPP-A and PlGF by euploid embryos at 14 d.p.f. compared to earlier timepoints (7 d.p.f.,p<0.01; 10d.p.f.,p<0.05). PAPP-A secretion did not increase in T21 embryos during extended culture. T21 embryos demonstrated decreased PAPP-A secretion at 10, 12, and 14 d.p.f. compared to euploid embryos (p < 0.01 in all cases). Secreted PlGF in T21 embryos rose significantly at 12 (p < 0.05) and 14 d.p.f. (p < 0.05), despite consistently lower levels than euploid embryos (p < 0.01). All studied proteins showed significantly diminished secretions during post-implantation development in M21 embryos compared to euploid ones. Comparing culture systems, the absence of maternal cells led to a significant decrease in secreted protein levels and viability impairment beyond 11 d.p.f. Consequently, only two timepoints (7- 10d.p.f.) were considered for analysis in this culture system. The findings underscore the potential of these secreted biomarkers for distinguishing embryo ploidy, with maternal co-culture supporting enhanced developmental outcomes. Limitations, reasons for caution This is an in-vitro pilot study that should be validated in larger cohorts. Wider implications of the findings Secretions of CALR, hPL, and PlGF at 7 d.p.f. effectively distinguish M21 embryos, while PAPP-A and PlGF secretions at 10-12 d.p.f. are indicative of embryo ploidy. Additionally, co-culturing with maternal cells notably promotes proper embryo development, particularly enhancing trophoblast differentiation and secretion of trophoblast-related proteins. Funding: ISCII(PI20/00405;PI23/00860;FI18/00009;MV21/00086); GVA (CIAICO/2022/203;CIAPOT/2022/18) and IDI-20210916 Trial registration number Not Applicable

CircATF6 inhibits hepatocellular carcinoma progression by suppressing calreticulin-mediated Wnt/β-catenin signaling pathway

Circular RNAs (circRNAs) are covalently closed, single-stranded RNAs that play critical roles in various biological processes and diseases, including cancers. However, the functions and mechanisms of circRNAs in hepatocellular carcinoma (HCC) need further clarification. Here, we identified and confirmed that circATF6 is downregulated in HCC tissues and negatively associated with the overall survival of HCC patients. Ectopic overexpression of circATF6 inhibits malignant phenotypes of HCC cells in vitro and in vivo, while knockdown of circATF6 had opposite effects. Mechanistically, we found that circATF6 bound to calreticulin (CALR) protein and acted as a scaffold to enhance the interaction of CALR with calpain2 (CAPN2), which promoted the degradation of CALR by its enzymatic activity. Moreover, we found that circATF6 inhibited HCC cells by suppressing CALR-mediated wnt/β-catenin signaling pathway. Taken together, our findings suggest that circATF6 is a potential prognostic biomarker and therapeutic target for HCC.

Synergistic action of gemcitabine and celecoxib in promoting the antitumor efficacy of anti-programmed death-1 monoclonal antibody by triggering immunogenic cell death.

Emerging evidence suggests that immunogenic chemotherapy not only kills tumor cells but also improves the immune-suppressive tumor microenvironment by inducing immunogenic cell death (ICD), leading to sustained anti-tumor effects. The lack of ICD inducers explored in lung cancer necessitates investigation into new inducers for this context, therefore, this study aims to explore whether the gemcitabine (GEM) and celecoxib can activate the immunogenic chemotherapy progress in lung cancer tissue. We assessed five chemotherapeutic agents for their ability to trigger ICD using ex vivo and in vivo experiments, including western blotting (WB), flow cytometry, and tumor preventive vaccine assays. Additionally, we evaluated the synergistic effects of GEM, celecoxib, and anti-programmed death 1 monoclonal antibody (aPD-1) in tumor-bearing mice to understand how GEM activates antitumor immunity and enhances immunochemotherapy. GEM was identified as an effective ICD inducer, showing high expression of calreticulin (CRT) and heat shock protein 90 (HSP90). Co-culture with GEM-treated cells [Lewis lung carcinoma (LLC) and CMT-64] enhanced dendritic cell (DC) activity, evidenced by maturation markers and increased phagocytic capacity. Moreover, celecoxib was found to enhance ICD by reducing indoleamine 2,3-dioxygenase 1 (IDO1) expression and increasing reactive oxygen species (ROS)-based endoplasmic reticulum (ER) stress. The combination therapy [GEM, celecoxib, and aPD-1 (GCP)] exhibited potent and sustained antitumor activity in immunocompetent mice, with enhanced recruitment of tumor-infiltrating lymphocytes. These findings support the potential use of GCP therapy as a treatment option for lung cancer patients.

Pediatric Myelofibrosis: A Rare Entity Posing a Diagnostic Challenge

Myeloproliferative neoplasms are clonal hematopoietic stem cell disorders showing proliferation of one or more myeloid lineages. These disorders are characterized by Janus Kinase 2 (JAK2 V617F), Myeloproliferative leukemia (MPL), and Calreticulin (CALR) gene mutations and are seen more commonly in the elderly. These pathognomonic mutations are often absent in children and hence pose a diagnostic challenge. The entire onus of correct diagnosis relies heavily on detailed clinical and laboratory investigations. In the present work, we discuss 4 cases of pediatric myelofibrosis, three of which were secondary to hematolymphoid malignancies, while the remaining one had primary myelofibrosis. Pediatric primary myelofibrosis is a rare entity in children and quite different from adult primary myelofibrosis. The cases in our study show transformation into acute myeloid leukemia, which is associated with an adverse prognosis. Given the rarity of myelofibrosis in children, early and correct diagnosis helps in timely initiation of treatment, which may favorably alter the prognosis.

White light increases anticancer effectiveness of iridium(III) complexes toward lung cancer A549 cells

Anticancer activity has been extensively studies. In this article, three ligands 2-(6-bromobenzo[d][1,3]dioxol-5-yl)-1H-imidazo[4,5-f][1,10]phenanthroline (BDIP), 2-(7-methoxybenzo[d][1,3]dioxol-5-yl)-1H-imidazo[4,5-f][1,10]phenanthroline (MDIP), 2-(6-nitrobenzo[d][1,3]dioxol-5-yl)-1H-imidazo[4,5-f][1,10]phenanthroline (NDIP) and their iridium(III) complexes: [Ir(ppy)2(BDIP)](PF6) (ppy = deprotonated 2-phenylpyridine, 3a), [Ir(ppy)2(MDIP)](PF6) (3b) and [Ir(ppy)2(NDIP)](PF6) (3c) were synthesized. The cytotoxicity of 3a, 3b, 3c against Huh7, A549, BEL-7402, HepG2, HeLa, and non-cancer NIH3T3 was tested using 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) method. The results obtained from the MTT test stated clearly that these complexes demonstrated moderate or non-cytotoxicity toward Huh7, BEL-7402, HepG2 and HeLa except A549 cells. To improve the anticancer efficacy, we used white light to irradiate the mixture of cells and complexes for 30 min, the anticancer activity of the complexes was greatly enhanced. Particularly, 3a and 3b exhibited heightened capability to inhibit A549 cells proliferation with IC50 (half maximal inhibitory concentration) values of 0.7 ± 0.3 μM and 1.8 ± 0.1 μM, respectively. Cellular uptake has shown that 3a and 3b can be accumulated in the cytoplasm. Wound healing and colony forming showed that 3a and 3b significantly hinder the cell migration and growth in the S phase. The complexes open mitochondrial permeability transition pore (MPTP) channel and cause the decrease of membrane potential, release of cytochrome C, activation of caspase 3, and finally lead to apoptosis. In addition, 3a and 3b cause autophagy, increase the lipid peroxidation and lead to ferroptosis. Also, 3a and 3b increase the expression of calreticulin (CRT), high mobility group box 1 (HMGB1), heat shock protein 70 (HSP70), thereby inducing immunogenic cell death.

Momelotinib - a promising advancement in the management of myelofibrosis in adults with anemia.

Myelofibrosis (MF) is a rare BCR-ABL negative myeloproliferative neoplasm characterized by clonal proliferation of stem cells, with mutations in JAK2, CALR, or MPL genes. MF presents in primary and secondary forms, with common symptoms including splenomegaly, anemia, and thrombocytopenia. Diagnostic criteria involve bone marrow examination and mutation studies. Current treatments are limited, with allogeneic stem cell transplant as the only curative option. Recent FDA approval of Momelotinib (MMB) offers new promise for MF patients with anemia. MMB, a JAK1/2 and ACVR1 inhibitor, effectively reduces spleen size, improves hemoglobin levels, and decreases transfusion dependency. The MOMENTUM trial compared MMB to danazol in JAK inhibitor-treated MF patients with anemia, showing MMB's superior symptom relief and transfusion independence rates. Additionally, the SIMPLIFY-1 and SIMPLIFY-2 trials evaluated MMB in JAK inhibitor-naïve and experienced patients, respectively, confirming MMB's non-inferiority to ruxolitinib in spleen volume reduction and highlighting its benefits in transfusion requirements. MMB's unique dual inhibition mechanism addresses anemia by suppressing hepcidin production, thus enhancing erythropoiesis. These trials collectively suggest MMB as an effective treatment for MF, improving quality of life and offering a survival advantage for patients with anemia. Despite challenges, such as trial design limitations and adverse events, MMB represents a significant advancement in MF management, providing a new therapeutic option for a previously underserved patient population.

Oncogenic Calreticulin Induces Immune Escape by Stimulating TGFβ Expression and Regulatory T-cell Expansion in the Bone Marrow Microenvironment.

Increasing evidence supports the interplay between oncogenic mutations and immune escape mechanisms. Strategies to counteract the immune escape mediated by oncogenic signaling could provide improved therapeutic options for patients with various malignancies. As mutant calreticulin (CALR) is a common driver of myeloproliferative neoplasms (MPN), we analyzed the impact of oncogenic CALRdel52 on the bone marrow (BM) microenvironment in MPN. Single-cell RNA sequencing revealed that CALRdel52 led to the expansion of TGFβ1-producing erythroid progenitor cells and promoted the expansion of FoxP3+ regulatory T cells (Treg) in a murine MPN model. Treatment with an anti-TGFβ antibody improved mouse survival and increased the glycolytic activity in CD4+ and CD8+ T cells in vivo, whereas T-cell depletion abrogated the protective effects conferred by neutralizing TGFβ. TGFβ1 reduced perforin and TNFα production by T cells in vitro. TGFβ1 production by CALRdel52 cells was dependent on JAK1/2, PI3K, and ERK activity, which activated the transcription factor Sp1 to induce TGFβ1 expression. In four independent patient cohorts, TGFβ1 expression was increased in the BM of patients with MPN compared with healthy individuals, and the BM of patients with MPN contained a higher frequency of Treg compared with healthy individuals. Together, this study identified an ERK/Sp1/TGFβ1 axis in CALRdel52 MPNs as a mechanism of immunosuppression that can be targeted to elicit T-cell-mediated cytotoxicity. Significance: Targeting the mutant calreticulin/TGFβ1 axis increases T-cell activity and glycolytic capacity, providing the rationale for conducting clinical trials on TGFβ antagonists as an immunotherapeutic strategy in patients with myeloproliferative neoplasms.