Calreticulin Expression Research Articles

PH and Redox Dual-Responsive Nanoparticle with Enhanced Dendritic Cell Maturation for Cancer Therapy.

Type I interferons (IFNs) are essential for activating dendritic cells (DCs) and presenting tumor-associated antigens to T cells. IFNs are primarily produced from DCs among immune cells. A combination of chemotherapy and metalloimmunotherapy induces IFN production by activating the cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) pathway. However, chemotherapeutic agents deplete DC populations, suppressing immunostimulatory activities, despite their potent anticancer activities. Furthermore, an optimal ratio between chemotherapeutic agents and metal for activating DCs at the highest level has not been reported, and evidence for ensuring DC survival is lacking. In this study, we hypothesized that there is an optimal ratio to yield the highest DC maturation and anticancer activity with minimal DC depletion. To demonstrate it, we have designed a pH and redox dual-responsive nanoparticle, MnO2@BSA@DOX (MD), to prevent DCs from depleting and activate the cGAS-STING pathway both in cancer cells and DCs, inducing considerable levels of IFNs and maturation. MD consists of a core-layer structure, a manganese dioxide (MnO2) core, and a cross-linked layer with bovine serum albumin (BSA) and doxorubicin (DOX), with a specific ratio of DOX to manganese. MD exhibits structure-based selectivity between cancer cells and DCs by targeting the extracellular pH of the tumor microenvironment and intracellular redox reactions in cancer cells. Among various formulations, the 1:1 ratio shows the highest maturation with no significant depletion. Moreover, it induces distinct cytotoxicity in cancer cells through apoptosis and cGAS-STING activation, leading to increased calreticulin expression and enhanced DC phagocytosis. Consequently, it results in superior tumor suppression and prolonged survival with the high accumulation of MD in the tumor and no observed systemic toxicities, highlighting its potential as a therapeutic agent in cancer treatments.

CD47 and Calreticulin Expression in Breast Cancer Subtypes and Anti-CD47 Inhibitory Effects in Macrophage-mediated Phagocytosis.

Macrophage-mediated cancer immune evasion is modulated by the balance between "the cluster of differentiation 47 (CD47), an anti-phagocytic signal" and "calreticulin (CALR), a pro-phagocytic signal". CD47 is highly expressed in various types of cancer. However, the expression profiles of CD47 and CALR in breast cancer, especially in different hormone receptor subtypes, and the effects of CD47 blockade in macrophage-mediated therapy are not well understood. The expression levels of CD47 and CALR were investigated in breast cancer and adjacent normal tissues using immunohistochemistry. To study the effects of CD47 blockade therapy, CD47 and CALR expression in breast cancer cell lines were determined. In vitro macrophage-mediated phagocytosis of breast cancer upon treatment with a monoclonal CD47 antibody (B6H12) were performed. CD47 and CALR were overexpressed in breast cancer tissues and their up-regulation was associated with hormone receptor subtypes. Patients with Luminal A breast cancer had higher levels of CD47, while patients with triple-negative breast cancer (TNBC) had higher levels of CALR. The levels of CD47 and CALR were also elevated in breast cancer cell lines of Luminal A (MCF-7) and TNBC (MDA-MB-231) subtypes. Interestingly, the expression ratio of surface CD47/CALR was significantly higher in MCF-7. Moreover, in vitro phagocytosis assays revealed that blockage of CD47 enhanced macrophage-mediated activity in both cancer cells with dramatically higher degrees of phagocytosis in MCF-7. The expression profiles of CD47 and CALR in breast cancer subtypes and the benefit of CD47 blocking-based immunotherapy are herein provided.

The relationship between TMCO1 and CALR in the pathological characteristics of prostate cancer and its effect on the metastasis of prostate cancer cells.

Calcium homeostasis is correlated closely with the occurrence and development of various cancers. The role of calcium homeostasis in prostate cancer has remained unclear. The present study aimed to investigate the relationship between transmembrane and crimp-crimp domain 1 (TMCO1) and calreticulin (CALR) in the pathological characteristics of prostate cancer and the mechanism of action on prostate cancer metastasis. Effects of CALR recombinant protein and TMCO1 knockdown on prostate cancer cells were investigated using following methods: cell cloning, Transwell, wound scratch assay, JC-1 assay, Fluo-4 Assay, endoplasmic reticulum (ER) fluorescent probe, mitochondrial fluorescence probe, Western blot and Immunofluorescence. TMCO1 and CALR are overexpressed in prostate cancer and knockdown of TMCO1 significantly inhibited the invasion, migration and cell proliferation. Furthermore, knocking down TMCO1 modulated the intensity of ER probes and mitochondrial fluorescence probes, and affected the levels of intracellular calcium ion and mitochondrial membrane potential. In addition, CALR recombinant protein upregulated the expression of epithelial-mesenchymal transition marker, Vimentin, Conversely, knockout of TMCO1 significantly reduced the expression of CALR and Vimentin. Knockout of TMCO1 can reverse the effect of CALR recombinant protein, elucidating the pivotal roles of TMCO1 and CALR in the regulation of prostate cancer metastasis through modulation of calcium homeostasis.

Molecular identification of EhCRT gene Calreticulin isolated from children infected with Entamoeba histolytica.

To detect the gene of entamoeba histolytica by polymerase chain reaction and investigate the expression of immunogene entamoeba histolytica calreticulin in stool samples of infected patients. The case control study was conducted at Central Teaching Hospital of Paediatrics and Al Mahmoudia General Hospital, Iraq, from December 30, 2020, to September 1, 2021, and comprised diarrhoeal faecal samples collected from 86 children with age ranging from ˂1 year to 13 years who were suspected of having been infected with entamoeba histolytica. Microscopically positive samples were then subjected to conventional and real-time polymerase chain reaction for the detection of entamoeba histolytica HM1:IMSS strain using Phage shock protein (Psp) gene sequences and detection of entamoeba histolytica calreticulin expression. Of the 86 patients, 71(82.6%) were found to be infected with entamoeba histolytica; 39(54.93%) boys and 32(45.07%) girls. The remaining 15(17.4%) patients were taken as non-amoebic controls; 8(53.3%) boys and 7(46.7%) girls. There were 36(50.70%) cases and 8(53.33%) controls aged 1-4 years. Among the Entamoeba histolytica gene was detected in 44(62%) of the cases using conventional polymerase chain reaction, and immunogene entamoeba histolytica calreticulin was expressed in 36(50.7%) using real-time polymerase chain reaction. Data was analysed using SPSS 24. Polymerase chain reaction was found to be a useful tool for diagnosing entamoeba histolytica infection in children.

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.

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.

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.

As1411-modified liposomes to enhance drug utilization and augment the anti-tumor efficacy

BackgroundThe utilization of liposomes in drug delivery has garnered significant attention due to their efficient drug loading capacity and excellent biocompatibility, rendering them a promising platform for tumor therapy. However, the average size of liposomes ~ 100 nm leads to liposomes being susceptible to hepatic and renal metabolism to excretion outside the body leading to poor drug delivery efficiency with a total utilization rate of less than 0.7%, resulting in unfavorable treatment outcomes.ResultsWe have developed a novel liposome platform equipped with tumor surface nucleolin-targeting capacity to enhance drug accumulation at the tumor in vivo. The encapsulation of doxorubicin through thin film hydration has resulted in the formation of D@L-AS1411. Through in vivo experiments, we have demonstrated the effective accumulation of D@L-AS1411 at the tumor site and its ability to improve doxorubicin utilization rates by 40%. Additionally, D@L-AS1411 induces immunogenic death of tumor cells, release of tumor-associated antigens, upregulation of calreticulin expression, and recruitment of active T cell infiltration, and ultimately improves the therapeutic efficacy against tumors (70%).ConclusionsBased on the nucleic acid aptamer AS1411, D@L-1411 is developed to specifically enhance the accumulation of Dox at tumor sites, thereby inhibiting and enhancing the anti-tumor effect. In summary, this study not only provides an efficient tumor-targeting delivery platform but also contributes to the improvement of chemotherapy–immunotherapy combination for tumor treatment strategy in the clinic.

Disulfiram/Copper Activates ER Stress to Promote Immunogenic Cell Death of Oral Squamous Cell Carcinoma.

Disulfiram/copper complex (DSF/Cu) was found to have anti-tumor effects in a range of malignancies, including oral squamous cell carcinoma (OSCC), yet its precise mechanism remains unknown. It has been shown that ER stress enhances immunogenic cell death (ICD) in tumor cells, as it can influence the anti-cancer immune system favorably. In this study, we reported that DSF/Cu exhibited a marked inhibitory effect on the growth of OSCC cells, accompanied by cell apoptosis. OSCC cells treated with DSF/Cu showed the hallmarks of immunogenic cell death (ICD), including surface expression of calreticulin (CRT), heat shock protein 70 (HSP70), high mobility-group box 1 (HMGB-1) and adenosine triphosphate (ATP), thus, eliciting the maturation and activation of dendritic cells. Furthermore, we showed DSF/Cu-induced endoplasmic reticulum (ER) stress in OSCC cells. In vivo, results demonstrate that DSF/Cu inhibits tumor growth locally and alters the intratumoral immune cell infiltration and response. In conclusion, DSF/Cu suppresses OSCC development by inducing ICD and ER stress. DSF/Cu has the potential to be a new anti-tumor immunotherapy concept because of its ability to elicit ICD.

Antileukemic potential of methylated indolequinone MAC681 through immunogenic necroptosis and PARP1 degradation

BackgroundDespite advancements in chronic myeloid leukemia (CML) therapy with tyrosine kinase inhibitors (TKIs), resistance and intolerance remain significant challenges. Leukemia stem cells (LSCs) and TKI-resistant cells rely on altered mitochondrial metabolism and oxidative phosphorylation. Targeting rewired energy metabolism and inducing non-apoptotic cell death, along with the release of damage-associated molecular patterns (DAMPs), can enhance therapeutic strategies and immunogenic therapies against CML and prevent the emergence of TKI-resistant cells and LSC persistence.MethodsTranscriptomic analysis was conducted using datasets of CML patients' stem cells and healthy cells. DNA damage was evaluated by fluorescent microscopy and flow cytometry. Cell death was assessed by trypan blue exclusion test, fluorescent microscopy, flow cytometry, colony formation assay, and in vivo Zebrafish xenografts. Energy metabolism was determined by measuring NAD+ and NADH levels, ATP production rate by Seahorse analyzer, and intracellular ATP content. Mitochondrial fitness was estimated by measurements of mitochondrial membrane potential, ROS, and calcium accumulation by flow cytometry, and morphology was visualized by TEM. Bioinformatic analysis, real-time qPCR, western blotting, chemical reaction prediction, and molecular docking were utilized to identify the drug target. The immunogenic potential was assessed by high mobility group box (HMGB)1 ELISA assay, luciferase-based extracellular ATP assay, ectopic calreticulin expression by flow cytometry, and validated by phagocytosis assay, and in vivo vaccination assay using syngeneic C57BL/6 mice.ResultsTranscriptomic analysis identified metabolic alterations and DNA repair deficiency signatures in CML patients. CML patients exhibited enrichment in immune system, DNA repair, and metabolic pathways. The gene signature associated with BRCA mutated tumors was enriched in CML datasets, suggesting a deficiency in double-strand break repair pathways. Additionally, poly(ADP-ribose) polymerase (PARP)1 was significantly upregulated in CML patients’ stem cells compared to healthy counterparts. Consistent with the CML patient DNA repair signature, treatment with the methylated indolequinone MAC681 induced DNA damage, mitochondrial dysfunction, calcium homeostasis disruption, metabolic catastrophe, and necroptotic-like cell death. In parallel, MAC681 led to PARP1 degradation that was prevented by 3-aminobenzamide. MAC681-treated myeloid leukemia cells released DAMPs and demonstrated the potential to generate an immunogenic vaccine in C57BL/6 mice. MAC681 and asciminib exhibited synergistic effects in killing both imatinib-sensitive and -resistant CML, opening new therapeutic opportunities.ConclusionsOverall, increasing the tumor mutational burden by PARP1 degradation and mitochondrial deregulation makes CML suitable for immunotherapy.

Biomimetic MDSCs membrane coated black phosphorus nanosheets system for photothermal therapy/photodynamic therapy synergized chemotherapy of cancer

Photothermal therapy is favored by cancer researchers due to its advantages such as controllable initiation, direct killing and immune promotion. However, the low enrichment efficiency of photosensitizer in tumor site and the limited effect of single use limits the further development of photothermal therapy. Herein, a photo-responsive multifunctional nanosystem was designed for cancer therapy, in which myeloid-derived suppressor cell (MDSC) membrane vesicle encapsulated decitabine-loaded black phosphorous (BP) nanosheets (BP@ Decitabine @MDSCs, named BDM). The BDM demonstrated excellent biosafety and biochemical characteristics, providing a suitable microenvironment for cancer cell killing. First, the BDM achieves the ability to be highly enriched at tumor sites by inheriting the ability of MDSCs to actively target tumor microenvironment. And then, BP nanosheets achieves hyperthermia and induces mitochondrial damage by its photothermal and photodynamic properties, which enhancing anti-tumor immunity mediated by immunogenic cell death (ICD). Meanwhile, intra-tumoral release of decitabine induced G2/M cell cycle arrest, further promoting tumor cell apoptosis. In vivo, the BMD showed significant inhibition of tumor growth with down-regulation of PCNA expression and increased expression of high mobility group B1 (HMGB1), calreticulin (CRT) and caspase 3. Flow cytometry revealed significantly decreased infiltration of MDSCs and M2-macrophages along with an increased proportion of CD4+, CD8+ T cells as well as CD103+ DCs, suggesting a potentiated anti-tumor immune response. In summary, BDM realizes photothermal therapy/photodynamic therapy synergized chemotherapy for cancer.

Induction of therapeutic immunity and cancer eradication through biofunctionalized liposome-like nanovesicles derived from irradiated-cancer cells.

Immunotherapy has revolutionized the treatment of cancer. However, its efficacy remains to be optimized. There are at least two major challenges in effectively eradicating cancer cells by immunotherapy. Firstly, cancer cells evade immune cell killing by down-regulating cell surface immune sensors. Secondly, immune cell dysfunction impairs their ability to execute anti-cancer functions. Radiotherapy, one of the cornerstones of cancer treatment, has the potential to enhance the immunogenicity of cancer cells and trigger an anti-tumor immune response. Inspired by this, we fabricate biofunctionalized liposome-like nanovesicles (BLNs) by exposing irradiated-cancer cells to ethanol, of which ethanol serves as a surfactant, inducing cancer cells pyroptosis-like cell death and facilitating nanovesicles shedding from cancer cell membrane. These BLNs are meticulously designed to disrupt both of the aforementioned mechanisms. On one hand, BLNs up-regulate the expression of calreticulin, an "eat me" signal on the surface of cancer cells, thus promoting macrophage phagocytosis of cancer cells. Additionally, BLNs are able to reprogram M2-like macrophages into an anti-cancer M1-like phenotype. Using a mouse model of malignant pleural effusion (MPE), an advanced-stage and immunotherapy-resistant cancer model, we demonstrate that BLNs significantly increase T cell infiltration and exhibit an ablative effect against MPE. When combined with PD-1 inhibitor (α-PD-1), we achieve a remarkable 63.6% cure rate (7 out of 11) among mice with MPE, while also inducing immunological memory effects. This work therefore introduces a unique strategy for overcoming immunotherapy resistance.

Effect of Calcium Supplementation and TMEM16A Inhibition on Endoplasmic Reticulum Stress Induced by Dental Fluorosis in Mice.

Dental fluorosis is a discoloration of the teeth caused by the excessive consumption of fluoride. It represents a distinct manifestation of chronic fluorosis in dental tissues, exerting adverse effects on the human body, particularly on teeth. The transmembrane protein 16a (TMEM16A) is expressed at the junction of the endoplasmic reticulum and the plasma membrane. Alterations in its channel activity can disrupt endoplasmic reticulum calcium homeostasis and intracellular calcium ion concentration, thereby inducing endoplasmic reticulum stress (ERS). This study aims to investigate the influence of calcium supplements and TMEM16A on ERS in dental fluorosis. C57BL/6 mice exhibiting dental fluorosis were subjected to an eight-week treatment with varying calcium concentrations: low (0.071%), medium (0.79%), and high (6.61%). Various assays, including Hematoxylin and Eosin (HE) staining, immunohistochemistry, real-time fluorescence quantitative polymerase chain reaction (qPCR), and Western blot, were employed to assess the impact of calcium supplements on fluoride content, ameloblast morphology, TMEM16A expression, and endoplasmic reticulum stress-related proteins (calreticulin (CRT), glucose-regulated protein 78 (GRP78), inositol requiring kinase 1α (IRE1α), PKR-like ER kinase (PERK), activating transcription factor 6 (ATF6)) in the incisors of mice affected by dental fluorosis. Furthermore, mice with dental fluorosis were treated with the TMEM16A inhibitor T16Ainh-A01 along with a medium-dose calcium to investigate the influence of TMEM16A on fluoride content, ameloblast morphology, and endoplasmic reticulum stress-related proteins in the context of mouse incisor fluorosis. In comparison to the model mice, the fluoride content in incisors significantly decreased following calcium supplements (p < 0.01). Moreover, the expression of TMEM16A, CRT, GRP78, IRE1α, PERK, and ATF6 were also exhibited a substantial reduction (p < 0.01), with the most pronounced effect observed in the medium-dose calcium group. Additionally, the fluoride content (p < 0.05) and the expression of CRT, GRP78, IRE1α, PERK, and ATF6 (p < 0.01) were further diminished following concurrent treatment with the TMEM16A inhibitor T16Ainh-A01 and a medium dose of calcium. The supplementation of calcium or the inhibition of TMEM16A expression appears to mitigate the detrimental effects of fluorosis by suppressing endoplasmic reticulum stress. These findings hold implications for identifying potential therapeutic targets in addressing dental fluorosis.

Abstract 1374: Targeting CD47/SIRPɑ axis in urologic cancer triggers enhanced phagocytosis of tumor cell and induces tumor growth inhibition

Abstract Signal regulatory protein-α (SIRPα; CD172a or SHPS-1) is a transmembrane molecule that highly expressed on myeloid population. Binding of CD47 (integrin-associated protein, IAP) to SIRPα inhibits phagocytosis in macrophages, which acts as a mechanism of maintaining homeostasis. Tumor cells however, often time upregulate CD47 to evade immune response. Using publicly available dataset, we found that human prostate cancer cells upregulate expression of both CD47 and calreticulin, a “eat me” signal when engaged with Low density lipoprotein receptor-related protein 1 (LRP1). In addition, macrophages, monocytes and dendritic cells in human prostate cancer do have relatively high level of SIRPɑ and LRP1 expression. This finding provides the rationale of targeting CD47/SIRPɑ axis in prostate cancer to shift the balance between pro-phagocytosis and anti-phagocytosis signaling. We then moved to RM1 and B6Cap, two syngeneic prostate cancer models in immunocompetent mice. Significant tumor growth inhibition was seen in both models with anti SIRPɑ blocking antibody. Furthermore, we observed in vitro that CD47 or SIRPɑ blockage led to enhanced PC3 cell line phagocytosis by human monocyte derived macrophages (HMDMs). Same finding was found using mouse bone marrow derived macrophages (BMDMs). We then utilized ovalbumin expressing MB49 bladder cancer cell line and cocultured those with BMDMs. CD8+ T cell from OT1 mice exhibited higher expression of activation makers when cocultured BMDMs treated by either anti CD47 or SIRPɑ antibody, indicating that enhanced phagocytosis subsequently increases antigen cross presentation in macrophages. In summary, we identified that CD47 is overexpressed in human prostate cancer; blocking CD47/SIRPɑ did inhibit tumor growth through enhanced phagocytosis and antigen presentation. Citation Format: Fan Shen, Monali Praharaj, Alex J. Lee, Thomas R. Nirschl, Xiaoxu Wang. Targeting CD47/SIRPɑ axis in urologic cancer triggers enhanced phagocytosis of tumor cell and induces tumor growth inhibition [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1374.

Abstract 587: Tumor treating fields induce the integrated stress response, alter the transcriptional signatures of cellular metabolism, and modulate immune-related cytokines dependent and independent of p53

Abstract Tumor treating fields (TTFields) are an FDA-approved therapy for the treatment of glioblastoma and pleural mesothelioma. TTFields employ alternating electric fields delivered by cutaneous transducer arrays to induce cytostatic and cytotoxic effects on solid tumors. Additionally, recent studies suggest that TTFields may enhance anti-tumor immunity. We performed RNA-seq and multiplexed cytokine profiling in HCT116 wild-type and HCT116 p53-/- human colorectal cancer cells to elucidate TTFields’ effects on the transcriptome and secretome. TTFields lead to profound changes in the transcriptome related to metabolism, including downregulation of transcripts coding for multiple enzymes involved in the Krebs cycle, fatty acid synthesis, and glycolysis. Furthermore, though only HCT116 p53-wild type cells strongly induced the p53 pathway, both cell types’ transcriptomes showed strong downregulation of cell cycle progression. Our cytokine data showed that key tumor-promoting cytokine IL-8 was downregulated independently of p53. We identified upregulation of immunomodulatory cytokines MIF and MICB independently of p53. While MICB promotes NK cell activation, MIF drives tumor progression. Therefore, MICB may be one way in which TTFields enhance anti-tumor immunity; targeting MIF during TTFields treatment may lead to synergy by abolishing its pro-tumor effects. We also identified a p53-dependent decrease in the TRAIL decoy receptor DcR3, which normally protects tumor cells from TRAIL-induced apoptosis. Further mechanistic work showed that TTFields induce EIF2-alpha phosphorylation, the central protein involved in activating the integrated stress response (ISR), across multiple cancer types, leading to suppression of global protein translation. TTFields treatment also resulted in increased expression of surface calreticulin, an endoplasmic reticulum stress marker, which activates the ISR. Future mechanistic work will explore the impact of identified cytokines and the ISR on anti-tumor immunity both in vitro and in vivo, as well as metabolic alterations induced by TTFields. This work identifies potential biomarkers and rationales for therapeutic combinations exploiting TTFields-induced molecular alterations. Citation Format: Praveen R. Srinivasan, Andrew George, Charissa Chou, Maximilian Pinho-Schwermann, Maryam Ghandali, Vida Tajiknia, Yaara Porat, Moshe Giladi, Andrea Armstead, Alper Uzun, Eric T. Wong, Wafik S. El-Deiry. Tumor treating fields induce the integrated stress response, alter the transcriptional signatures of cellular metabolism, and modulate immune-related cytokines dependent and independent of p53 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 587.

Abstract 6742: PV 10 induces endoplasmic reticulum stress and autophagy, triggering immunogenic cell death and anti-tumor immunity in head and neck squamous cell carcinoma

Abstract Introduction: Head and neck squamous cell carcinoma (HNSCC) are complex, diverse cancers affecting mucosal linings of the upper aerodigestive tract. Globally, HNSCC is the sixth most common cancer, leading to over 890,000 new cases and more than 450,000 deaths annually. Primary risk factors include human papillomavirus (HPV) infection (HPV-positive HNSCC) and exposure to tobacco and excessive alcohol (HPV-negative HNSCC). Despite multimodal treatments, survival rates remain low due to recurrence and metastasis (R/M HNSCC), creating a need for safe, innovative therapies to reduce tumor burden with minimal adverse events. PV-10 (10% rose bengal sodium) is a novel intratumoral immunotherapeutic agent that has demonstrated promising anti-tumor activity in multiple solid tumor cancer types with few adverse effects in pre-clinical research and clinical trials. However, the role of PV-10 in HNSCCs and its role in enhancing immune response warrants further investigation. Methods: Cell viability was assessed using Alamar blue assay after PV-10 treatment of murine mEER and MTE-RAS HNSCC tumor cell lines. To evaluate the immunomodulatory properties of PV-10, we employed flow cytometry, confocal analysis, and luminescence-based assays. Additionally, we performed a DCFDA assay to measure the reactive oxygen species (ROS) and an Alexa Fluor 488 Annexin V/dead cell apoptosis assay to evaluate apoptosis. To gain insights into the mechanisms underlying PV-10's immunomodulatory effects in cancer cells and tumors from mice, western blotting and multiplex immunohistochemistry (mIHC) were used. Results: Our in vitro findings reveal that PV-10 induces cytotoxicity in both mEER and MTE-RAS cells. Notably, PV-10 promotes a significant increase in ROS, leading to an elevation in late apoptotic cells. Markers of immunogenic cell death (ICD), including a statistically significant increase in the release of damage-associated molecular pattern molecules HMGB1 and ATP, as well as enhanced surface expression of calreticulin, HSP-70, and HSP-90, were observed. At the molecular level, a remarkable activation of endoplasmic reticulum (ER) stress, pro-apoptotic protein, and autophagy markers were observed. Intratumoral PV-10 injection in vivo has shown significant tumor regression in both mEER and MTE-RAS tumors, and a complete response was noticed in some mice, indicating that PV-10 induces potent ICD in both mEER and MTE-RAS tumors. Conclusion: Our collated evidence strongly suggests that PV-10 induces ICD-associated immunogenicity in both mEER and MTE-RAS in vitro and in vivo, fostered by ROS-based ER stress and apoptosis. These findings hold promise for potential therapeutic avenues to manage HNSCC. Citation Format: Sowjanya Thatikonda, Ritu Chaudhary, Yeva Meshkovska, Maria I. Biernacki, Robbert Slebos, Shari P. Thomas, Amelio L. Antonio, Eric A. Wachter, Christine H. Chung. PV 10 induces endoplasmic reticulum stress and autophagy, triggering immunogenic cell death and anti-tumor immunity in head and neck squamous cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6742.

Nano-delivery of Silibinin Potentiate the Induction of Immunogenic Cell Death (ICD) in Melanoma Cells.

Induction of immunogenic cell death (ICD) in tumors can enhance antitumor immunity and modulate immunosuppression in the tumor microenvironment (TME). In the current study, we investigated the effect of silibinin, a natural compound with anticancer activity, and its polymer-based nanoformulations on the induction of apoptosis and ICD in cancer cells. Free and nanoparticulate silibinin were evaluated for their growth-inhibitory effects using an MTT assay. Annexin V/PI staining was used to analyze apoptosis. Calreticulin (CRT) expression was measured by flow cytometry. Western blotting was conducted to examine the levels of elf2α, which plays a role in the ICD pathway. The HSP90 and ATP levels were determined using specific detection kits. Compared to the free drug, silibinin-loaded nanocarriers significantly increased the induction of apoptosis and ICD in B16F10 cells. ICD induction was characterized by significantly increased levels of ICD biomarkers, including CRT, HSP90, and ATP. We also observed an increased expression of p-elf-2α/ elf-2α in B16F10 cells treated with silibinin-loaded micelles compared to cells that received free silibinin. Our findings showed that the encapsulation of silibinin in polymeric nanocarriers can potentiate the effects of this drug on the induction of apoptosis and ICD in B16F10 melanoma cells.

Calreticulin, a potential coregulator of immune checkpoints and biomarker associated with tumor microenvironment and clinical prognostic significance in breast invasive carcinoma.

As a promising immune checkpoint of immunogenic cell death (ICD) and multifunctional calcium-binding molecular chaperone, calreticulin (CALR) has been attracting increasing attention. CALR mainly locates in cellular endoplasmic reticulum and significantly affects cell proliferation, invasion, induction of apoptosis, and angiogenesis in breast invasive carcinoma (BRCA). CALR overexpression might be correlated with a worse outcome. Nonetheless, it remains obscure how CALR correlates with immune infiltration and survival prognosis of BRCA. In this study, we investigated CALR expression utilizing RNAseq data from the cancer genome atlas (TCGA) and genotype-tissue expression (GTEx) database. The prognostic value of CALR was analyzed using clinical survival data. Enrichment analysis was conducted using the R package "clusterProfiler." We downloaded the immune cell infiltration score of TCGA samples from published articles and online databases and performed a correlation analysis between immune cell infiltration levels and CALR expression. We further assessed the association between CALR and immunomodulators. Moreover, we also evaluated the expression of CALR in 100 formalin-fixed and paraffin-embedded breast cancer and adjacent normal breast tissue specimens. Our results found that CALR was highly expressed in BRCA, and CALR expression levels differed in pathological stages, T stages, and N stages. Besides, these results suggested that CALR overexpression may have adverse effects on the progression-free interval (PFI) and disease-free interval (DFI), which may be related to tumor proliferation, invasion, and metastasis, leading to tumor deterioration. Meanwhile, immune cell infiltration analysis revealed a correlation between the expression of CALR and the number of neutrophils and dendritic cells, suggesting that CALR was highly correlated with many immunomodulators in BRCA. Our results provide potential biomarkers of CALR in BRCA. CALR may interact synergistically with other immunomodulators to regulate the immune microenvironment, which could be utilized to develop new immunotherapy drugs.

HOCl sensitivity associates with a reduced p53 transcriptional network and calreticulin expression in 25 human cancer cell lines

Reactive oxygen species (ROS) play roles in physiological processes and pathological conditions. Higher ROS levels induce oxidative distress and cytotoxic responses, such as chronic inflammatory conditions and cancer. While the cellular responses of various cell types to cytotoxic pro-oxidative conditions have been well studied in the past decades, much less is known about the cellular gene and expression profiles that are a priori associated with subsequent cellular demise to oxidative stress. To this end, we used 25 human cancer cell lines of different origins and established the inhibitory concentration (IC25) of hypochlorous acid (HOCl), an oxidant readily produced by neutrophils frequently present in many inflamed tissues, including cancer. The HOCl sensitivity varied throughout the 25 cell lines investigated, showing a more than 5-fold difference between the most sensitive and resistant types. In parallel, we investigated untreated cells and their basal gene expression using transcriptomic microarray and performed correlation analyses to HOCl IC25 values of all cell lines. Transcriptomic analyses and functional classification of significant correlating genes revealed reduced expression of tumor protein p53 signaling network members, including BAX, CDKN1A (p21), and BTG2, as well as the p53 gene (TP53) itself to associate with cell line sensitivity to HOCl toxicity. Further, baseline surface membrane expression analysis of 33 inflammation- and redox-related molecules identified nitric oxide (NO) synthase 2 and the ER-stress-associated chaperone calreticulin to correlate significantly with HOCl resistance. We identified targets associated with HOCl sensitivity. Nevertheless, further studies are needed to map gene and protein expression patterns associated with oxidative stress-induced cytotoxicity.

Membranal Expression of Calreticulin Induced by Unfolded Protein Response in Melanocytes: A Mechanism Underlying Oxidative Stress–Induced Autoimmunity in Vitiligo

Calreticulin (CRT), a damage-associated molecular pattern molecule, is reported to translocate from endoplasmic reticulum to membrane in melanocytes under oxidative stress. To investigate the potential role of CRT in the pathogenesis of vitiligo, we analyzed the correlation between CRT and ROS in serum and lesions of vitiligo, detected CRT and protein kinase RNA-like ER kinase (PERK) expression in vitiligo lesions, and studied the production of CRT and mediators of unfolded protein response (UPR) pathway, then tested the chemotactic migration of CD8+ T cells or CD11c+ CD86+ cells. Initially, we verified the overexpression of CRT in perilesional epidermis that was positively correlated with the disease severity of vitiligo. Furthermore, the PERK branch of UPR was confirmed to be responsible for the overexpression and membranal translocation of CRT in melanocytes under oxidative stress. We also found that oxidative stress-induced membranal translocation of CRT promoted the activation and migration of CD8+ T cells in vitiligo. Additionally, dendritic cells from vitiligo patients were also prone to maturation with the co-incubation of melanocytes harboring membranal CRT. CRT could be induced on the membrane of melanocytes via UPR and might play a role in oxidative stress-triggered CD8+ T cell response in vitiligo.