CD44 Antibody Research Articles

CD47 in Osteosarcoma: Correlation with Metastasis and Macrophage-Mediated Phagocytosis.

CD47 is expressed on cell surfaces and acts as a "don't eat me" signal by interacting with signal-regulatory protein-α on the macrophage surface. Some cancer cells express CD47 protein and can evade macrophage phagocytosis. Herein, we evaluated the feasibility of targeting CD47 for osteosarcoma by analyzing its expression patterns, clinicopathological correlations, and immunotherapeutic potential. We performed a retrospective analysis on 24 biopsy samples from patients with osteosarcoma to investigate correlations between CD47 protein positivity and clinicopathological characteristics. CD47 protein expression was detected in 20.8% of the biopsy samples. CD47 positivity correlated with metastasis at diagnosis. Patients with CD47-positive tumors were older than those with CD47-negative tumors. However, CD47 protein expression was not associated with sex, tumor size, or histologic response to preoperative chemotherapy. In vitro, CD47 antibody (B6H12) did not affect osteosarcoma cell viability or apoptosis. In a wound-healing assay, CD47 inhibited the migration of osteosarcoma cells. Differentiated macrophages exhibited higher phagocytic activity against osteosarcoma cells when pretreated with B6H12 compared with the isotype control. Our preliminary data suggest a possible interaction between CD47 protein and macrophage phagocytosis in osteosarcoma metastasis. A better understanding of the role of CD47 is necessary to develop an innovative immunotherapeutic approach against osteosarcoma.

Enhanced Macrophages Engulfment by Peptide‐Templated Nanoassemblies Targeting SIRPα and Suppressing Oxidative Stress for Atherosclerosis Pro‐Efferocytotic Therapy

AbstractPrompt removal of apoptotic cells via macrophage‐mediated efferocytosis is an emerging approach for atherosclerosis treatment, because these diseased cells directly contribute to vascular inflammation and secondary necrosis in plaques. Despite blocking CD47 can restore impaired efferocytosis by inhibiting “don't eat me” signals, the currently available CD47 antibody (CD47‐Ab)‐based therapy may accelerate off‐target clearance of healthy cells due to the ubiquitous expression of CD47 on viable cells. Here, a peptide‐templated nanoassembly (PTna‐1) engineered to induce synergistic enhancement of engulfment by macrophages is reported. Through self‐assembled polypeptides with multiple functional motifs, the nanoassembly can specifically target p32‐overexpressing macrophages and bind to the Ig‐V‐like domain of SIRPα but not to CD47, thereby normalizing intraplaque efferocytosis and alleviating persistent inflammation. Concurrently, disassembled PTna‐1 released manganese porphyrins with photoacoustic/magnetic resonance imaging capability to suppress oxidative stress and synergistically enhance macrophage phagocytosis through the RhoA/ROCK1 pathway. Compared with CD47‐Abs, PTna‐1 promoted a more significant reduction in lesion area and plaque stabilization without affecting the incidence of anemia in atherosclerotic mice. Proteomic analysis revealed that PTna‐1 treatment decreased the expression of inflammation‐related proteins in plaques. Overall, these peptide‐driven nanoassemblies employing a SIRPα‐specific blockade strategy provide a distinct paradigm of pro‐efferocytotic therapy for atherosclerosis.

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.

Genetic Signatures: CD44 Single-Nucleotide Polymorphisms Affect Cell Surface Expression and Elevate Risk in Head and Neck Squamous Cell Carcinoma.

This study aimed to investigate the impact of single-nucleotide polymorphisms (SNPs) in the CD44 gene, specifically in the 3'UTR region (rs13347) and intronic region (rs187115), on the cell surface expression of CD44 protein and the risk of development of head and neck squamous cell carcinoma (HNSCC). The study involved analysis of 85 samples and 85 healthy controls. Immunohistochemistry (IHC) and flow cytometry were used to assess cell surface protein expression using CD44 antibody. DNA from formalin-fixed paraffin-embedded tissue sections was isolated and amplified using targeted primers. Sanger sequencing of the resultant amplified products was performed to determine the genotypes of the CD44 rs13347 and rs187115 SNPs. GTEx and RegulomeDB were queried to evaluate the genotypic effects of these variants on target gene expression and regulation. A comparison between patients with HNSCC and healthy controls revealed a significant association between CD44 rs13347 and an increased risk of HNSCC in all the analyzed models, especially the TT genotype showed a significantly higher risk with an odds ratio of 8.69 (95% CI, 2.35 to 32.09; P = .0003). However, no significant association was found between CD44 rs187115 and HNSCC in any of the models analyzed (all P > .05). Other notable findings included significant associations between CD44 rs13347 genotype and age (P = .031), number of CD44-positive tumor cells (P = .049), CD44 staining intensity (SI; P = .039), and CD44 immunoreactivity score (IRS) status (P = .019). The T allele and homozygous TT genotype of CD44 rs13347 SNP were associated with increased susceptibility to HNSCC and decreased proportion of CD44-positive tumor cells, low SI, and reduced IRS.

Bisphenol A-induced oxidative stress increases the production of ovarian cancer stem cells in mice

Bisphenol A (BPA) belongs to the endocrine disruptor chemicals (EDCs) causing various reproductive disorders in females. We analysed the toxic effects of BPA in the uterus and ovaries. The BPA was administered orally with the repeated low dose (LD, 1 mg/kg) and high dose (HD, 5 mg/kg) of body weight on alternate days for 4 months via oral gavage to Swiss mice. BPA administration decreases body weight, ovarian weight and size at LD, but increases ovarian weight and size at HD. The uterus weight, length, and diameter were increased in both the treated groups. The histopathological data show decreased ovarian follicle size, epithelial hyperplasia, and lymphocytic infiltration in the ovary. The BPA-treated uterus shows increased vascularization, atrophied endometrium and myometrium, and endometrial hyperplasia (EH) with aberrant glandular growth. The cancer stem cells (CSCs) in the ovaries were identified based on staining with anti-mouse CD44 and anti-mouse CD133 antibodies and analysed by flow cytometry. Three different populations of ovarian CSCs: CD44+CD133-, CD44+CD133+, and CD44−CD133+, can be recognised based on the intensity of these receptors. CD44+CD133- and CD44+CD133+ cell percentages were increased in BPA-treated groups. CD44−CD133+ were increased in LD but decreased in HD. The BPA administration also induces ROS production, which decreases the expression of antioxidant genes Superoxide dismutase 1 (SOD1), Superoxide dismutase 2 (SOD2), Catalase (CAT), Glutathione peroxidase 1 (GPX1), and Forkhead box O3 (FOXO3) in ovarian cells. In conclusion, BPA exposure induced an inflammatory response, increased CSC proportions, induced ROS, and decreased antioxidant responses in the ovaries.

Dual‐Targeted Engineered Bacterial Outer Membrane Vesicles for Hepatocellular Carcinoma Immunotherapy

AbstractCluster of differentiation 47 (CD47) is an important innate immune checkpoint that empowers tumors to send “don't eat me” signals, leading to immune escape. CD47 monoclonal antibodies have achieved remarkable therapeutic success in hematological malignancies. However, their efficacy in solid tumors is limited, mainly because of immunosuppression in the tumor microenvironment. In addition, hematotoxicity severely hinders the clinical translation of CD47 antibodies. Here, a novel genetically programmed nanovesicle, OMV‐CD47/GPC3, is generated for hepatocellular carcinoma (HCC) immunotherapy by fusing anti‐CD47 nanobodies and anti‐GPC3 scFv onto bacterial outer membrane vesicles (OMVs). Following intravenous administration, dual‐targeted OMV‐CD47/GPC3 specifically recognized tumor cells expressing both CD47 and GPC3, thereby actively targeting and accumulating at the orthotopic HCC tumor site without hematotoxicity. OMV‐CD47/GPC3 potently blocked tumor CD47 and promoted macrophage phagocytosis. More importantly, immunogenic OMV‐CD47/GPC3 can effectively remodel the tumor immune microenvironment of orthotopic HCC, especially reprogram tumor‐associated macrophages (TAMs) to the M1‐phenotype and promote dendritic cell maturation, synergistically inducing a robust CD8+ T cell‐mediated anti‐tumor immune response. With the two‐pronged approach of immune checkpoint inhibition and immune activation, engineered OMV‐CD47/GPC3 significantly suppressed orthotopic HCC growth and prevented tumor recurrence and metastasis, thus providing a promising strategy for HCC immunotherapy.

Label-free optical fiber biosensor for the detection of CD44-expressing breast cancer cells

Increased level of CD44, transmembrane glycoprotein, is observed in several cancers such as breast, colorectal, head and neck, gastric, and ovarian cancer. Current methods for analyzing CD44 expressing cells are time-consuming, semi-quantitative, use labeled reagents for analysis or are not suitable for in situ analysis. Therefore exploring novel methods which are label-free and fast with the in situ detection capability for the quantification of these cells is of importance.Using optical fiber as a sensing element in biosensors offers low cost, high sensitivity, chemical inertness, and immunity to electromagnetic interference, and possibility of being used in in situ applications. This study reports the first label-free optical fiber biosensor for detection of CD44-expressing cancer cells. A fiber-optic ball resonator (BR) sensor was fabricated and then functionalized with CD44 antibodies. Different concentrations of the cells were incubated with the biosensor to measure the reflected light using optical backscatter reflectometer. The biosensor was able to detect cancer cells with a limit of detection of 335 cells/mL. The presence of the cells on the sensor surface was demonstrated by fluorescent and scanning electron microscope analysis. The work is the first proof-of-concept biosensor based on optical fibers for CD44 cancer cells and acts as a promising tool for in situ detection of cancer cells.

#2339 All-trans retinoic acid enhances the efficacy of mesenchymal stem cells in acute kidney injury

Abstract Background and Aims Mesenchymal stem cells (MSCs) have emerged as a promising therapeutic strategy for acute kidney injury (AKI), but still suffer from the drawbacks of low survival rate, low homing rate, and uncertain differentiation. In search of better therapeutic strategies, we explored all-trans retinoic acid (ATRA) pretreatment of MSCs to observe whether it could improve the therapeutic efficacy on AKI. Method We established a renal ischemia/reperfusion (I/R) injury model induced by clamping of left renal artery for 30 minutes and contralateral nephrectomy. C57BL/6 mice were randomly divided into 4 groups: sham group, IRI group, MSCs group, and ATRA-MSCs group. MSCs or ATRA-pretreated MSCs were injected via tail vein. GFR was measured by transcutaneous monitoring the clearance of FITC-sinistrin. These mice were sacrificed 3 days after surgery, and the serum creatinine (SCr) and blood urea nitrogen (BUN) levels were measured. The renal pathological changes were examined by Periodic Acid-Schiff staining (PAS). The in vitro hypoxia/reoxygenation (H/R) model was established using human proximal tubular epithelial cells (HK-2 cells). Co-culturing HK-2 cells with MSCs or ATRA-pretreated MSCs. Western blot, quantitative real time-PCR (qRT-PCR), and immunohistochemistry were used to detect mRNA or protein expression. We performed RNA sequencing (RNA-seq) analysis in ATRA-pretreated MSCs. The content of hyaluronic acid (HA) in the supernatant of ATRA-pretreated MSCs culture was detected by ELISA. Hyaluronan synthase mRNA expression level in ATRA-pretreated MSCs assessed by qRT-PCR analysis. The HAS2 promoter-binding transcription factors were forecasted by the JASPAR Transcription Factor Binding Site database. Western blot was used to detect whether P13K/AKT pathway was activated by ATRA-pretreated MSCs. Whether this nephroprotective effect could be reversed were explored by silencing HAS2 or CD44 antibodies. Results The AKI mice showed a significant decrease in GFR and even complete loss of renal function. Administration of MSCs significantly increased GFR, and MSCs pretreated with ATRA further increased GFR. Mice injected with ATRA-pretreated MSCs had significantly lower levels of SCr, BUN and ATN scores compared with untreated MSCs. Western blot, quantitative real-time PCR (qRT-PCR), and immunohistochemistry showed that ATRA pretreated MSCs were more effective in reducing AKI inflammation and apoptosis and promoting proliferative repair than untreated MSCs. GO enrichment analysis demonstrated that the hyaluronan biosynthetic process may be a significantly expressed. HAS2 expression and HA content of MSCS were significantly increased after the addition of ATRA. Analysis for potential transcription factor binding sites revealed that the HAS2 promoter region has multiple potential binding sites for the retinoic acid receptor. Based on the predictions from the JASPAR database, the RXR-RAR heterodimer had the highest prediction score. We then performed ChIP analysis to experimentally verify the binding of RXR-RAR heterodimer transcription factor to HAS2 promoters. We further found that ATRA-pretreated MSCs activated the PI3K/AKT signaling pathway in AKI. As expected, we found that ATRA-pretreated MSCs anti-inflammatory, anti-apoptosis, and pro-proliferation effects were substantially reversed by silencing HAS2 or blocking CD44. Conclusion ATRA promotes HA secretion from MSCs and activates the PI3K/AKT pathway, which in turn enhances the therapeutic efficacy of MSCs on AKI.

#1805 Renal progenitor cells isolated from urine of IgA nephropathy patients formed renal spheroids that can recapitulate the typical IgA1 deposition

Abstract Background and Aims Recent developments in stem cell biology have made it possible to create spheroids and kidney organoids from human and mouse pluripotent stem cells and renal stem cells. Spheroids are a suitable in vitro model for studies of drug studies and can transform into organoids whose rapidly developing field has proven useful in simulating nephrotoxicity, kidney disorders, and kidney development. However, to date in all studies the generation of organoids and tubuloids required the use of sophisticated and complex differentiation protocols involving external administration of several growth factors and needs compliance with a precise and specific timescale. Here we showed for the first time that human adult renal progenitor cells (ARPCs) can be isolated from urines of healthy subjects (HS) or IgA Nephropathy (IgAN) patients and can form spheroids generating very long tubule-like structures naturally, without the external use of chemokines or growth factors to artificially induce the process and recapitulating the IgA1 deposition that is the typical characteristic of the disease. Method Spheroids and tubule-like structures were characterized by whole-mounting and frozen section immunofluorescence (IF) assays and by Flow Cytometry Analysis using CD133, NanoG, Oct3/4, GATA-3, SSEA4, CD249, Aminopepidase N, ZO-1, Uromodulin, and Lotus Tetragonolobus Lectin (LTL) antibodies. ELISA was used to determine the renin secretion and CAM assays to determine ARPCs and ARPC-derived Spheroids angiogenic properties. PKH-26 labeling was used for their in vitro and in vivo tracking. Serum of HS and IgAN patients in culture with spheroids was used to recapitulate the disease and IgA1 deposits were measured by IF. Results ARPC-derived spheroids reflected the renal progenitor properties and recapitulated organoids generating very long tubule-like structures that expressed structural and functional renal tubule markers such as CD249, Aminopepidase N, ZO-1, Uromodulin, and LTL and in some cases shared many structural similarities with some regions of nephrons, such as the distal convoluted tubule, the loop of Henle and proximal convoluted tubules. Moreover, ARPC-derived spheroids secreted elevated levels of renin and, as the cellular counterpart, showed angiogenic properties. To study the proof of concept that ARPC-derived spheroids can be used to establish in vitro models recapitulating renal diseases, we generated IgAN patient-specific renal spheroids using the ARPC mixed cell population method. ARPC-derived spheroids of IgAN patients showed deposits of IgA1 already after four days of culture with patient serum (p = 0.004) and, with a different pattern, after 8 and 15 days (p = 0.0029 and p = 0.0012, respectively). The IgA1 deposition resembled that in the glomeruli of patients diagnosticated with IgAN. In contrast, no positive signal was detected in either IgAN spheroids in culture with FBS, or with inactivated IgAN serum, as well as in spheroids derived from urine of HS in culture with IgAN serum. Conclusion The ability of ARPCs to form spheroids and differentiate into tubular-like structures without the need for external chemokines or growth factors is a significant advancement in the field, even more considering that these cells can be isolated from the urine of patients. These findings open up new possibilities for the regenerative medicine in studying kidney development, disease mechanisms, and regenerative therapy development for renal disorders.

Is drug interference still an issue for pretransfusion testing of patients on anti CD38 and other monoclonal antibody therapies?

Certain therapies that target CD markers on some blood cells can affect pretransfusion testing. Key examples are anti-CD38, CD47 monoclonal antibody (mAb) therapies such as daratumumab (DARA) and magrolimab, which have presented a challenge for transfusion medicine laboratories around the globe. Scientists have been faced with not only introducing a protocol to provide safe blood to patients but also investigating the most effective method to remove the pretransfusion pan-agglutinating interference caused. A number of papers in the last 5 years have reported on various methods to remove pretransfusion interference; however, most of these studies have been conducted only in a few countries. Most recent reviews on this topic have focused on techniques and reagents to remove pretransfusion interference, and dithiothreitol is currently the gold standard for removing DARA interference. However, it was clear from this review that while many laboratories have developed processes for addressing interference in pretransfusion testing, and DARA interference may not be a major issue, there are still laboratories around the world, that may not have adequately addressed this issue. In addition, the impact of mAb interference on widely used techniques such as flow cytometry is unclear.

Photoimmunotheranostics of epithelioid sarcoma by targeting CD44 or EGFR

Epithelioid sarcoma (ES) is a rare soft tissue neoplasm with high recurrence rates. Wide surgical resection remains the only potential curative treatment. ES presents most commonly on the fingers, hands and forearm, making light-based cancer cell-targeted therapies such as near-infrared photoimmunotherapy (NIR-PIT) that is target-specific, but with limited penetration depth, suitable for ES treatment. We established that CD44 and EGFR were overexpressed in ES patient samples and in the VA-ES-BJ human ES cell line. NIR-PIT of VA-ES-BJ cells using antibody photosensitizer conjugates, prepared by conjugating a CD44 or EGFR monoclonal antibody to the photosensitizer IR700, confirmed that NIR-PIT with both conjugates resulted in cell death. Neither treatment with NIR light alone nor treatment with the conjugates but without NIR light were effective. CD44-IR700-PIT resulted in greater cell death than EGFR-IR700-PIT, consistent with the increased expression of CD44 by VA-ES-BJ cells. In tumors, EGFR-IR700 exhibited a higher tumor-to-normal ratio, as determined by in vivo fluorescence imaging, and a higher anti-tumor growth effect, compared to CD44-IR700. No antitumor effect of the EGFR antibody or the photosensitizer conjugate alone was observed in vivo. Our data support evaluating the use of EGFR-IR700-PIT in the management of ES for detecting and eliminating ES cells in surgical margins, and in the treatment of superficial recurrent tumors.

Macrophage Checkpoint Nanoimmunotherapy Has the Potential to Reduce Malignant Progression in Bioengineered In Vitro Models of Ovarian Cancer.

Most ovarian carcinoma (OvCa) patients present with advanced disease at the time of diagnosis. Malignant, metastatic OvCa is invasive and has poor prognosis, exposing the need for improved therapeutic targeting. High CD47 (OvCa) and SIRPα (macrophage) expression has been linked to decreased survival, making this interaction a significant target for therapeutic discovery. Even so, previous attempts have fallen short, limited by CD47 antibody specificity and efficacy. Macrophages are an important component of the OvCa tumor microenvironment and are manipulated to aid in cancer progression via CD47-SIRPα signaling. Thus, we have leveraged lipid-based nanoparticles (LNPs) to design a therapy uniquely situated to home to phagocytic macrophages expressing the SIRPα protein in metastatic OvCa. CD47-SIRPα presence was evaluated in patient histological sections using immunohistochemistry. 3D tumor spheroids generated on a hanging drop array with OVCAR3 high-grade serous OvCa and THP-1-derived macrophages created a representative model of cellular interactions involved in metastatic OvCa. Microfluidic techniques were employed to generate LNPs encapsulating SIRPα siRNA (siSIRPα) to affect the CD47-SIRPα signaling between the OvCa and macrophages. siSIRPα LNPs were characterized for optimal size, charge, and encapsulation efficiency. Uptake of the siSIRPα LNPs by macrophages was assessed by Incucyte. Following 48 h of 25 nM siSIRPα treatment, OvCa/macrophage heterospheroids were evaluated for SIRPα knockdown, platinum chemoresistance, and invasiveness. OvCa patient tumors and in vitro heterospheroids expressed CD47 and SIRPα. Macrophages in OvCa spheroids increased carboplatin resistance and invasion, indicating a more malignant phenotype. We observed successful LNP uptake by macrophages causing significant reduction in SIRPα gene and protein expressions and subsequent reversal of pro-tumoral alternative activation. Disrupting CD47-SIRPα interactions resulted in sensitizing OvCa/macrophage heterospheroids to platinum chemotherapy and reversal of cellular invasion outside of heterospheroids. Ultimately, our results strongly indicate the potential of using LNP-based nanoimmunotherapy to reduce malignant progression of ovarian cancer.

Abstract 3126: A novel pegylated bispecific antibody-drug conjugate (P-BsADC) JY207b targeting cancers co-expressing PD-L1 and CD47

Abstract ADCs have showed improved efficacy and target selectivity comparing to the non-specific small molecule cytotoxicity drugs. However, conventional IgG based ADC has been hindered in solid tumor therapies by the poor tumor penetration, low internalization efficiency, unexpected efflux from tumor cells, and narrow therapeutic window due to the on target/off tumor toxicity, etc. To address these issues, we have developed the pegylated bispecific ADC platform and proved the concept with JY207, which targets PD-L1 and CD47 with a 30k PEG-MMAE linker-payload. JY207 has demonstrated advantages in tumor penetration, internalization efficiency, without efflux post internalization, lacking Fc related toxicity, and better tumor inhibition than DS-8201a in a model positive for Her2, PD-L1 and CD47. In this study, we further improved the compound by site-specific conjugating the fusion protein of two scFvs that target PD-L1 and CD47, with a 40K PEG-MMAE linker-payload. As expected, the new compound JY207b retained all the advantages of JY207. Additionally, JY207b did not bind to human red blood cells at all even though an ultra-sensitive detection method was employed, while CD47 antibodies with reported low affinity bound >90% red blood cells under our ultra-sensitive detection method. Meanwhile, JY207b could still preferentially bind to CD47/PD-L1 double positive tumor cells, thus reducing the possibility of on-target toxicities. In the in vitro cytotoxicity assays, the compound JY207b demonstrated strong potencies in CD47/PD-L1 double positive tumor cells, with almost no killing effect to CD47 or PD-L1 single positive tumor cells. In CDX models and a PDX model of transplanted tumor tissues from lung cancer patients, the compound JY207b demonstrated strong tumor inhibition efficacies at low doses. More interestingly, although the elimination half-life (T1/2) of JY207b in mice is 59.17±3.824 hours, the elimination time of JY207b in tumors is beyond 1 week by the IVIS imaging examination, which allows for weekly dosing in PK unfavorable mouse animals for pegylated protein drugs. Moreover, preliminary repeated-dosing toxicological study has found the maximum tolerated dose of JY207 in CD47/PD-L1 double transgenic mice to be 50mg/kg. These studies suggested favorable anti-tumor effect of JY207 both in vitro and in vivo, and its mechanism of action has been well described. These findings provide evidence for the efficacy of JY207 as a clinical treatment for patients with CD47/PD-L1 double positive cancers. Citation Format: Yu (Yvonne) Wen, Shumin Liu, Weidong Lyu, Yang Lei, Shuangyu Tan, Zibin Wu, Shuqiang Yin, Qiudong Zhuo, Dechun Wu. A novel pegylated bispecific antibody-drug conjugate (P-BsADC) JY207b targeting cancers co-expressing PD-L1 and CD47 [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 3126.

Effects of a humanized CD47 antibody and recombinant SIRPα proteins on triple negative breast carcinoma stem cells.

Signal regulatory protein-α (SIRPα, SHPS-1, CD172a) expressed on myeloid cells transmits inhibitory signals when it engages its counter-receptor CD47 on an adjacent cell. Elevated CD47 expression on some cancer cells thereby serves as an innate immune checkpoint that limits phagocytic clearance of tumor cells by macrophages and antigen presentation to T cells. Antibodies and recombinant SIRPα constructs that block the CD47-SIRPα interaction on macrophages exhibit anti-tumor activities in mouse models and are in ongoing clinical trials for treating several human cancers. Based on prior evidence that engaging SIRPα can also alter CD47 signaling in some nonmalignant cells, we compared direct effects of recombinant SIRPα-Fc and a humanized CD47 antibody that inhibits CD47-SIRPα interaction (CC-90002) on CD47 signaling in cancer stem cells derived from the MDA-MB- 231 triple-negative breast carcinoma cell line. Treatment with SIRPα-Fc significantly increased the formation of mammospheres by breast cancer stem cells as compared to CC-90002 treatment or controls. Furthermore, SIRPα-Fc treatment upregulated mRNA and protein expression of ALDH1 and altered the expression of genes involved in epithelial/mesenchymal transition pathways that are associated with a poor prognosis and enhanced metastatic activity. This indicates that SIRPα-Fc has CD47-mediated agonist activities in breast cancer stem cells affecting proliferation and metastasis pathways that differ from those of CC-90002. This SIRPα-induced CD47 signaling in breast carcinoma cells may limit the efficacy of SIRPα decoy therapeutics intended to stimulate innate antitumor immune responses.

Enhancement of cytotoxic and apoptotic activity through oolong tea extract-mediated CuO/Cu2O nanoparticles

The development of multifunctional nanoformulations with enhanced anticancer activity and drug delivery potential is of increasing scientific importance. In this study, we synthesized and characterized copper oxide nanoparticles mediated by oolong tea extract (OE-CuO/Cu2O NPs) using a variety of techniques, including TEM, XRD, FTIR, and UV–Vis spectroscopy, to assess their physical and chemical properties. Remarkably, the results revealed that OE/CuO NPs exhibited significantly enhanced anticancer activity compared to OE alone. The effects of OE and OE-CuO/Cu2O NPs were on cytotoxicity, apoptosis, and cell cycle progression. Furthermore, we assessed the impact of these nanostructures on CD44/24 antibodies, known as aggressive cell markers, following treatment. The green OE-CuO/Cu2O NPs displayed remarkable inhibitory effects on colon cancer HCT116 and breast cancer cells MCF-7 cells. It was shown that OE-CuO/Cu2O NPs reduced the production of the CD44 antibody, provided cell cycle arrest, and encouraged apoptosis. More specifically, it was discovered that these NPs caused MCF-7 cells to undergo apoptosis and G2/M phase cell cycle arrest. Additionally, drug delivery investigations were conducted to evaluate the potential of OE-CuO/Cu2O NPs as drug nanocarriers, further underscoring their promise in developing novel anticancer agents with significant cytotoxic, apoptotic, and drug delivery properties.

Enhanced potency of immunotherapy against B-cell precursor acute lymphoblastic leukemia by combination of an Fc-engineered CD19 antibody and CD47 blockade.

CD19-directed immunotherapy has become a cornerstone in the therapy of B-cell precursor acute lymphoblastic leukemia (BCP-ALL). CD19-directed cellular and antibody-based therapeutics have entered therapy of primary and relapsed disease and contributed to improved outcomes in relapsed disease and lower therapy toxicity. However, efficacy remains limited in many cases due to a lack of therapy response, short remission phases, or antigen escape. Here, BCP-ALL cell lines, patient-derived xenograft (PDX) samples, human macrophages, and an in vivo transplantation model in NOD.Cg-PrkdcscidIl2rgtm1Wjl/SzJ (NSG) mice were used to examine the therapeutic potency of a CD19 antibody Fc-engineered for improved effector cell recruitment (CD19-DE) and antibody-dependent cellular phagocytosis (ADCP), in combination with a novel modified CD47 antibody (Hu5F9-IgG2σ). For the in vivo model, only samples refractory to CD19-DE monotherapy were chosen. Hu5F9-IgG2σ enhanced ADCP by CD19-DE in various BCP-ALL cell line models with varying CD19 surface expression and cytogenetic backgrounds, two of which contained the KMT2A-AFF1 fusion. Also, the antibody combination was efficient in inducing ADCP by human macrophages in pediatric PDX samples with and adult samples with and without KMT2A-rearrangement in vitro. In a randomized phase 2-like PDX trial using seven KMT2A-rearranged BCP-ALL samples in NSG mice, the CD19/CD47 antibody combination proved highly efficient. Our findings support that the efficacy of Fc-engineered CD19 antibodies may be substantially enhanced by a combination with CD47 blockade. This suggests that the combination may be a promising therapy option for BCP-ALL, especially in relapsed patients and/or patients refractory to CD19-directed therapy.

Differentiating Malignant and Benign Lesion in Thyroid, Is There Any New Marker?

The most common malignancy of the endocrine gland is papillary thyroid carcinoma (90% of endocrine malignancy). In many cases, the tumor showed borderline morphology between benign lesions and characteristics of papillary thyroid carcinoma. To determine malignancy, we propose new markers to assist with these difficulties and challenges. This research aims to determine the sensitivity and specificity of CD44 and CDK4 immunostaining in diagnosing papillary thyroid carcinoma. Samples of paraffin blocks with histopathology diagnosis of papillary thyroid carcinoma and components of benign thyroid follicular cells from January 2019 to December 2022 were collected. Immunohistochemical staining was done using CD44 and CDK4 antibodies. The staining in papillary thyroid carcinoma cells and benign thyroid follicular cells were compared. Conclusions: All papillary thyroid carcinoma cells expressed CD44 and CDK4 antibodies (100%), whereas 78.9% of benign thyroid follicular cells did not express CD44 and 81.57% did not express CDK4. CD44 and CDK4 could be useful in diagnosing papillary thyroid carcinoma with a sensitivity of 100% and specificity of 78.9% and 81.57% respectively.

Immunohistochemical Expression of Autophagy-Related Marker (LC3B) and Stem Cell Marker (CD44) in Molecular Subtypes of Breast Cancer.

Breast cancer (BC) is among the most prevalent aggressive type of malignancy affecting females worldwide. Despite the advance in early detection and management of BC; recurrence, metastasis and mortality remains high. This may be attributed to heterogeneity of BC which explained by the presence of breast cancer stem cells (BCSCs). BCSCs is characterized by their ability of self-renewal, unlimited proliferation and their differentiation potential. BCSCs maintain their activity through process of autophagy. Autophagy is a catabolic pathway important for maintenance of cellular hemostasis in response to different stressful conditions. Autophagy allows BCSCs to adapt to different stressful conditions. So, it protects BCSCs from cytotoxic effects of anti-cancer therapy and anticancer resistance. Formalin-fixed paraffin embedded fifty specimens of Invasive duct carcinoma of no special type(IDC/NST) of breast was selected and immunostained with stem cell marker CD44 and autophagy related marker LC3B antibodies. Correlation with different clinicopathological, histopathological characteristics and molecular subtypes of studied specimens were evaluated. Both CD44 and LC3B expression were significantly associated with lymph nodal metastasis (p =0.001 and 0.010 respectively), advanced pathological stage (p= 0.045 and 0.004 respectively) and with triple negative molecular subtype of BC (p=0.044 and 0.048 respectively). Statistically positive correlation was also found between both tumor markers expression. Results of this study suggests that CD44 and LC3B expression play a role in the clinical behavior and progression of different molecular subtypes of BC.

Regulation of CD47 expression on CD14+ monocytes by interferon-α in PBC patients.

Primary biliary cholangitis (PBC) is a chronic intrahepatic cholestatic autoimmune liver disease characterized by inflammatory injury of small and medium-sized bile ducts in the liver. The pathogenesis of PBC has yet to be entirely understood. CD47/signal-regulatory protein alpha (SIRPα) is closely related to developing autoimmune diseases by promoting inflammatory response. However, the effect of CD47/SIRPα on inflammatory response in PBC patients is still unclear. We investigated the expression of CD47/SIRPα and the effect of inflammatory cytokines on the CD47 expression, analyzed potential autoantibodies against CD47 and the effect of anti-CD47 antibody on the inflammatory response in PBC, provided laboratory basis for the study of the pathogenesis and targets for non-invasive diagnosis and treatment on PBC. The expression levels of CD47 and SIRPα on peripheral blood mononuclear cells (PBMC) were measured in 14 patients with PBC (the PBC group) and 13 healthy subjects (the Control group) by flow cytometry (FCM). The PBMC derived from healthy subjects were stimulated with healthy subjects' serum, PBC patients' serum, IFN-α or TNF-α, and the CD47 expression level on CD14+ monocytes was detected by FCM. The level of serum anti-CD47 antibody or IFN-α in PBC patients and healthy subjects was analyzed by ELISA. FCM was used to examine the TNF-α expression level in CD14+ monocytes of healthy subjects stimulated with isotype control antibody, anti-CD47 antibody, LPS or LPS combined with CD47 antibody. The CD47 expression level on the CD14+ monocytes in PBC patients was statistically higher than that in the Control group (P<0.01). Compared with the Control group (PBMC+healthy serum), the CD47 expression on CD14+ monocyte stimulated with the PBC patients' serum (PBMC+PBC patients' serum) was increased (P<0.001); the CD47 expression on CD14+ monocyte stimulated with IFN-α (PBMC + IFN-α) increased gradually with the increased concentration of IFN-α (P<0.05). However, there was no similar trend on CD14+ monocyte stimulated with the TNF-α (PBMC+TNF-α) (P>0.05). The levels of serum anti-CD47 antibody and IFN-α in the PBC patients were higher than those in healthy subjects (P<0.05). The TNF-α expression level in CD14+ monocyte stimulated with the LPS (PBMC+LPS) or anti-CD47 antibody+LPS group (PBMC+LPS+anti-CD47 antibody) was significantly increased than that in the Control group (PBMC+isotype control antibody) (P<0.01 and P<0.001, respectively). The TNF-α expression level in CD14+ monocyte stimulated with the anti-CD47 antibody + LPS was higher than that with the LPS (P< 0.05). The CD47 may be related to the pathogenesis of PBC by inflammatory response. The CD47/SIRPα signal were imbalanced in PBC patients. The presence of serum anti-CD47 antibodies in PBC patients provides a laboratory basis for clinical diagnosis and treatment.

The Potent Dihydroorotate Dehydrogenase Inhibitor, Hosu-53, Exhibits Compelling Monotherapy Efficacy in Multiple Myeloma and Augments CD47 Targeted Therapy

Worldwide, multiple myeloma (MM) is the second most common hematological malignancy characterized by the expansion of aberrant mature plasma cells in the bone marrow. Despite the FDA approval of several drugs with different mechanisms of action such as immunomodulatory drugs (IMiDs) and proteosome inhibitors (PIs), MM remains a challenging incurable disease where most patients ultimately relapse and become refractory to available . The resistant nature of MM underscores the need for novel therapeutic strategies that can directly affect MM cells while enhancing the outcome with MM current standard of care (SOC). Among the most promising MM SOC agents is monoclonal antibodies (mAb) such as the CD38 antibody daratumumab, which significantly improved the management of newly diagnosed and relapsed/refractory MM. Therefore, we aimed to develop novel therapies that can enhance mAb therapy in MM. Dihydroorotate dehydrogenase (DHODH) is an enzyme which mediates the fourth and rate-limiting step in the de novo pyrimidine synthesis pathway converting dihydroorotate to orotate, the precursor of uridine. Pyrimidine starvation using DHODH inhibitors has been shown to have potent antiproliferative activity in several malignancies including acute myeloid leukemia (AML) and MM. Thus, we developed a novel potent DHODH inhibitor, HOSU-53 for the treatment of hematological malignancies. We previously discovered the ability of HOSU-53 to modulate surface CD38 expression and found that HOSU-53 had potent monotherapy activity in MM and provided impressive synergy in combination with daratumumab using the NCI-H929 MM cell line derived xenograft (CDX) model (2022 AACR annual meeting abstracts). Herein, we further expanded our studies to pre-clinically develop HOSU-53 as a new potential MM therapy and explore additional synergistic immunotherapy combinations that could maintain efficacy in the case of anti-CD38 therapy resistance. We evaluated the in vitro antiproliferative efficacy of HOSU-53 against a panel of MM cell lines and found nanomolar potency validating that HOSU-53 would have monotherapy efficacy. Indeed, we conducted in vivo studies using two additional MM CDX subcutaneous (s.c) models, OPM-2 and RPMI-8226, and found significant tumor delay and survival advantage. In the OPM-2 model, HOSU-53 has a median survival of 54-days compared to vehicle at 28-days, while the median survival for HOSU-53 was 60-days compared to vehicle at 26-days in the RPMI-8226 model. We further verified HOSU-53 efficacy using the disseminated MM1.S luciferase CDX model and found a significant prolonged survival in the HOSU-53 cohort (median survival53-days) compared to vehicle (median survival28-days) that was further enhanced with isatuximab combination resulting in superior survival benefit (median survival 69-days). Given the continuous challenge in maintaining a durable response with anti-CD38 therapies due to resistance, we sought to explore additional combination regimens to maximize HOSU-53 efficacy. Currently there is significant clinical interest in CD47 antibody therapy such as magrolimab for both solid tumors and hematological malignancies. Our previous work suggested a strong synergy between CD47 antibodies and HOSU-53 in AML with curative potential (2022 ASH annual meeting abstracts), and hypothesized that we would observe similar synergy with HOSU-53 in combination with anti-CD47 in MM. Indeed, we found complete tumor regression in all mice treated with HOSU-53 + B6.H12 anti-CD47 therapy in the NCI-H929 s.c CDX model and significant prolonged survival and reduced bioluminescence in the NCI-H929 luciferase disseminated CDX model. Together, these two studies validate a potential clinical benefit to explore HOSU-53 + anti-CD47 regimen in MM patients. Furthermore, we observed that calreticulin (pro-phagocytosis signal) was modulated post HOSU-53 in vitro treatment suggesting its role in the observed synergy between HOSU-53 and CD47 blockade therapy. In summary, we show compelling survival benefit for HOSU-53 as a monotherapy which is further enhanced when combined with anti-CD38 or anti-CD47 therapies. HOSU-53 is expected to enter phase 1 clinical trials in 2024 and our data is supportive for its expansion into MM.