Significant Antitumor Effect Research Articles

Discovery of novel exceptionally potent and orally active c-MET PROTACs for the treatment of tumors with MET alterations

Various c-mesenchymal-to-epithelial transition (c-MET) inhibitors are effective in the treatment of non-small cell lung cancer; however, the inevitable drug resistance remains a challenge, limiting their clinical efficacy. Therefore, novel strategies targeting c-MET are urgently required. Herein, through rational structure optimization, we obtained novel exceptionally potent and orally active c-MET proteolysis targeting chimeras (PROTACs) namely D10 and D15 based on thalidomide and tepotinib. D10 and D15 inhibited cell growth with low nanomolar IC50 values and achieved picomolar DC50 values and >99% of maximum degradation (Dmax) in EBC-1 and Hs746T cells. Mechanistically, D10 and D15 dramatically induced cell apoptosis, G1 cell cycle arrest and inhibited cell migration and invasion. Notably, intraperitoneal administration of D10 and D15 significantly inhibited tumor growth in the EBC-1 xenograft model and oral administration of D15 induced approximately complete tumor suppression in the Hs746T xenograft model with well-tolerated dose-schedules. Furthermore, D10 and D15 exerted significant anti-tumor effect in cells with c-METY1230H and c-METD1228N mutations, which are resistant to tepotinib in clinic. These findings demonstrated that D10 and D15 could serve as candidates for the treatment of tumors with MET alterations.

Aprepitant inhibits the development and metastasis of gallbladder cancer via ROS and MAPK activation

BackgroundAprepitant, as a neurokinin-1 receptor (NK-1R) antagonist, originally applied for curing chemotherapy-induced nausea and vomiting, has been reported to have significant antitumor effect on several malignant tumors. However, the effect of aprepitant on gallbladder cancer (GBC) is not clear yet. This study aimed to investigate the anti-tumor activity of aprepitant on GBC and the potential mechanisms.MethodsThe NK-1R expression of gallbladder cancer cells were examined by immunofluorescence. MTT assay, wound healing and transwell migration assay were applied to detect the effect of aprepitant on cell proliferation, migration and invasion. Flow cytometry was used to detect the apoptosis rate. The effects of aprepitant on the expressions of cytokine were examined by real-time quantitative PCR and MAPK activation were detected via immunofluorescence and western blotting. Besides, xenograft model was established to investigate the effect of aprepitant in vivo.ResultsOur results indicated that NK‐1R was markedly expressed in gallbladder cancer cells and aprepitant effectively inhibited the proliferation, migration and invasion. Furthermore, the apoptosis, ROS and inflammation response were significantly boosted by aprepitant in GBC. Aprepitant induced NF‐κB p65 nuclear translocationin and increased the expressions of p-P65, p-Akt, p-JNK, p-ERK and p-P38, as well as the mRNA levels of inflammatory cytokines IL-1β, IL-6 and TNF-α. Consistently, aprepitant suppressed the growth of GBC in xenograft mice model.ConclusionOur study demonstrated that aprepitant could inhibit the development of gallbladder cancer via inducing ROS and MAPK activation, which suggested that aprepitant may become a promising therapeutic drug against GBC.

Discovery of a Selective and Orally Bioavailable FGFR2 Degrader for Treating Gastric Cancer.

Abnormal activation of fibroblast growth factor receptors (FGFRs) results in the development and progression of human cancers. FGFR2 is frequently amplified or mutated in cancers; therefore, it is an attractive target for tumor therapy. Despite the development of several pan-FGFR inhibitors, their long-term therapeutic efficacy is hindered by acquired mutations and low isoform selectivity. Herein, we report the discovery of an efficient and selective FGFR2 proteolysis-targeting chimeric molecule, LC-MB12, that incorporates an essential rigid linker. LC-MB12 preferentially internalizes and degrades membrane-bound FGFR2 among the four FGFR isoforms; this may promote greater clinical benefits. LC-MB12 exhibits superior potency in FGFR signaling suppression and anti-proliferative activity compared to the parental inhibitor. Furthermore, LC-MB12 is orally bioavailable and shows significant antitumor effects in FGFR2-dependent gastric cancer in vivo. Taken together, LC-MB12 is a candidate FGFR2 degrader for alternative FGFR2-targeting strategies and offers a promising starting point for drug development.

Copper Increases the Sensitivity of Cholangiocarcinoma Cells to Tripterine by Inhibiting TMX2-Mediated Unfolded Protein Reaction Activation.

Chemotherapy-induced adaptive resistance is a significant factor that contributes to low therapeutic efficacy in tumor cells. The unfolded protein response (UPR) is a key mechanism in the development of drug resistance and serves as a critical reactive system for endoplasmic reticulum stress. Cu(II) can reduce the abundance of 60S ribosomal subunits and inhibit rRNA processing, leading to a decrease in the translation efficiency of the GRP78/BiP mRNA, which serves as a primary sensor for UPR activation. In this study, CuET-Lipid@Cela, composed of CuET and tripterine (Cela), demonstrates a significant synergistic antitumor effect on cholangiocarcinoma (CCA) cells. RNA-Seq is used to investigate the underlying mechanism, which suggests that the transmembrane protein 2 (TMX2) gene may be crucial in Cu(II) regulation of UPR by inhibiting the activation of GRP78/BiP and PERK/eIF2α. The synergistic antitumor efficacy of CuET-Lipid@Cela via inhibition of TMX2 is also confirmed in a myrAKT/YapS127A plasmid-induced primary CCA mouse model, providing new insights into the reversal of acquired chemotherapy-induced resistance in CCA.

5-FU mediated depletion of myeloid suppressor cells enhances T-cell infiltration and anti-tumor response in immunotherapy–resistant lung tumor

Tumor microenvironment (TME) is a heterogeneous system consisting of both cellular and acellular components. The growth and progression of tumors rely greatly on the nature of TME, marking it as an important target in cancer immunotherapy. Lewis Lung Carcinoma (LLC) is an established murine lung cancer model representing immunologically ‘cold’ tumors characterized by very few infiltrated cytotoxic T-cells, high levels of Myeloid-Derived Suppressor Cells (MDSCs) and Tumor-Associated Macrophages (TAMs). Here, we report various strategies we applied to reverse the non-immunogenic character of this cold tumor by imparting: a) immunogenic cell death using Hypericin nanoparticle-based photodynamic therapy (PDT), b) repolarising TAM using a TLR7/8 agonist, resiquimod, c) immune checkpoint inhibition using anti-PD-L1 and d) depleting MDSCs using low-dose 5-fluorouracil (5-FU) chemotherapy. Interestingly, the nano-PDT, resiquimod or anti-PD-L1 treatment had no major impact on tumor growth, whereas low-dose 5-FU-mediated depletion of MDSCs showed significant anti-tumor effect, primarily caused by the increased infiltration of CD8+ cytotoxic T-cells (∼96%). Though we have tested combining PDT with resiquimod or 5-FU for any synergistic effect, low-dose 5-FU alone showed better response than combinations. In effect, we show that depletion of MDSCs using low-dose 5-FU was one of the best methods to augment infiltration of CD8+ cytotoxic T-cells into a cold tumor, which is resistant to conventional therapies including immune checkpoint inhibitors.

Ado-tratuzumab emtansine beyond breast cancer: therapeutic role of targeting other HER2-positive cancers.

Ado-trastuzumab emtansine (T-DM1) is an antibody-drug conjugate approved by the FDA in 2013 for advanced HER2-positive breast cancer treatment exhibiting promising clinical benefits. However, HER2 overexpression and gene amplification have also been reported in other cancers like gastric cancer, non-small cell lung cancer (NSCLC), and colorectal cancer. Numerous preclinical studies have also revealed the significant antitumor effect of T-DM1 on HER2-positive tumors. With the advancement in research, several clinical trials have been conducted to investigate the antitumor effect of T-DM1. In this review, we briefly introduced the pharmacological effects of T-DM1. We reviewed its preclinical and clinical studies, especially on other HER2-positive cancers, establishing what has been encountered between its preclinical and clinical studies. In clinical studies, we found that T-DM1 has a therapeutic value on other cancers. An insignificant effect was observed on gastric cancer and NSCLC, inconsistent with the preclinical studies.

Preparation and characterization of pH-responsive Zein-ZnPc-PDA/HA nanoparticles intended for tumor therapy

Photodynamic therapy (PDT) has emerged as a non-invasive modality where photosensitizer (PS) plays an indispensable role for treating tumors. This study proposes a novel Zein nanoparticle (ZP) encapsulating Zinc phthalocyanine (ZnPc) that targets tumor through intravenous delivery. The ZPs were prepared by phase separation process. Modification of ZPs were realized through encapsulation of polydopamine (PDA) and hyaluronic acid (HA) in order to maintain photothermal, pH-responsive, and tumor-targeting properties. The physiochemical properties, in vitro release, and in vitro evaluation of photothermal and photodynamic effects were studied. The biosafety was analyzed through cytotoxicity assay using human lung cancer cell line A549 as model. The excellent biosafety and significant anti-tumor effect demonstrated that the novel ZPs can be potential candidates for the alternative treatment of cancer.

Expanding Transition Metal-Mediated Bioorthogonal Decaging to Include C–C Bond Cleavage Reactions

The ability to control the activation of prodrugs by transition metals has been shown to have great potential for controlled drug release in cancer cells. However, the strategies developed so far promote the cleavage of C-O or C-N bonds, which limits the scope of drugs to only those that present amino or hydroxyl groups. Here, we report the decaging of an ortho-quinone prodrug, a propargylated β-lapachone derivative, through a palladium-mediated C-C bond cleavage. The reaction's kinetic and mechanistic behavior was studied under biological conditions along with computer modeling. The results indicate that palladium (II) is the active species for the depropargylation reaction, activating the triple bond for nucleophilic attack by a water molecule before the C-C bond cleavage takes place. Palladium iodide nanoparticles were found to efficiently trigger the C-C bond cleavage reaction under biocompatible conditions. In drug activation assays in cells, the protected analogue of β-lapachone was activated by nontoxic amounts of nanoparticles, which restored drug toxicity. The palladium-mediated ortho-quinone prodrug activation was further demonstrated in zebrafish tumor xenografts, which resulted in a significant anti-tumoral effect. This work expands the transition-metal-mediated bioorthogonal decaging toolbox to include cleavage of C-C bonds and payloads that were previously not accessible by conventional strategies.

Chang Wei Qing Decoction enhances the anti-tumor effect of PD-1 inhibitor therapy by regulating the immune microenvironment and gut microbiota in colorectal cancer.

The anti-tumor effect of anti-PD-1 antibody has long been shown to be strongly related to the tumor immune microenvironment (TIME). This study aimed to mechanistically assess whether Chang Wei Qing (CWQ) Decoction can enhance the anti-tumor effect of PD-1 inhibitor therapy. PD-1 inhibitor therapy showed the significant anti-tumor effect in patients with mismatch repair-deficient/microsatellite instability-high (dMMR/MSI-H) colorectal cancer (CRC), rather than those with mismatch repair-proficient/microsatellite stable (pMMR/MSS) CRC. Hence, immunofluorescence double-label staining was utilized to explore the difference in the TIME between dMMR/MSI-H and pMMR/MSS CRC patients. Flow cytometry was used to analyze T-lymphocytes in tumors from mice. Western blot was used to measure the expression of PD-L1 protein in mouse tumors. The intestinal mucosal barrier of mice was evaluated by hematoxylin-eosin staining and immunohistochemistry. 16S rRNA-gene sequencing was used to examine the structure of the gut microbiota in mice. Subsequently, Spearmanapos;s correlation analysis was used to analyze the relationship between the gut microbiota and tumor-infiltrating T-lymphocytes. The results showed that dMMR/MSI-H CRC patients had more CD8+T cells and higher expression of PD-1 and PD-L1 proteins. In vivo, CWQ enhanced the anti-tumor effect of anti-PD-1 antibody and increased the infiltration of CD8+ and PD-1+CD8+ T cells in tumors. Additionally, the combination of CWQ with anti-PD-1 antibody resulted in lower inflammation in the intestinal mucosa than that induced by anti-PD-1 antibody alone. CWQ and anti-PD-1 antibody co-treatment upregulated PD-L1 protein and reduced the abundance of Bacteroides in the gut microbiota but increased the abundance of Akkermansia,Firmicutes, andActinobacteria. Additionally, the proportion of infiltrated CD8+PD-1+, CD8+, and CD3+ T cells were found to be positively correlated with the abundance of Akkermansia. Accordingly, CWQ may modulate the TIME by modifying the gut microbiota and consequently enhance the anti-tumor effect of PD-1 inhibitor therapy.

N6-methyladenosine RNA modification in PD-1/PD-L1: Novel implications for immunotherapy.

Cancer immunotherapy has been shown to achieve significant antitumor effects in a variety of malignancies. Out of all the immune checkpoint molecules, PD-1/PD-L1 inhibitor therapy has achieved great success. However, only some cancer patients benefit from this treatment strategy owing to drug resistance. Therefore, identifying the underlying modulators of the PD-1/PD-L1 pathway to completely comprehend the mechanisms of anti-PD-1/PD-L1 treatment is crucially important. Recent research has validated that m6A modification plays a critical role in the PD-1/PD-L1 axis, thus regulating the immune response and immunotherapy strategies. In this review, we summarized the latest research on the regulation of m6A modification in PD-1/PD-L1 pathways in cancer proliferation, invasion, and prognosis based on different kinds of cancers and discussed the possible mechanisms. We also reviewed m6A-associated lncRNAs in the regulation of the PD-1/PD-L1 pathway. More importantly, we outlined the influence of m6A modulation on anti-PD-1 therapy and m6A-related molecules that could predict the curative effect of anti-PD-1/PD-L1 therapy. Further studies exploring the definitive regulation of m6A on the PD1/PD-1 pathway and immunotherapy are needed, which may address some of the current limitations in immunotherapy.

Universal chimeric Fcγ receptor T cells with appropriate affinity for IgG1 antibody exhibit optimal antitumor efficacy.

Developing universal CARs with improved flexible targeting and controllable activities is urgently needed. While several studies have suggested the potential of CD16a in tandem with monoclonal antibodies to construct universal CAR-T cells, the weak affinity between them is one of the limiting factors for efficacy. Herein, we systematically investigated the impact of Fcγ receptor (FcγR) affinity on CAR-T cells properties by constructing universal CARs using Fcγ receptors with different affinities for IgG1 antibodies, namely CD16a, CD32a, and CD64. We demonstrated that the activities of these universal CAR-T cells on tumor cells could be redirected and regulated by IgG1 antibodies. In xenografted mice, 64CAR chimeric Jurkat cells with the highest affinity showed significant antitumor effects in combination with herceptin in the HER2 low expression U251 MG model. However, in the CD20 high expression Raji model, 64CAR caused excessive activation of CAR-T cells, which resulted in cytokine release syndrome (CRS) and the decline of antitumor activity, and 32CAR with a moderate affinity brought the best efficacy. Our work extended the knowledge about FcγR-based universal CAR-T cells and suggested that only the FcγRCAR with an appropriate affinity can offer the optimal antitumor advantages of CAR-T cells.

Q1VA, a Synthetic Chalcone, Induces Apoptosis and Decreases Invasion on Primary Culture of Human Glioblastoma

Glioblastoma (GBM) is the most commonly occurring type of primary tumor of the central nervous system (CNS) and is considered the worst type of glioma. Despite the current standard treatment for newly diagnosed GBM, which involves surgery followed by chemotherapy with temozolomide (TMZ) and radiation therapy, the average survival time for patients with GBM is only about 15 months. This is due to GBM’s tendency to recur, its high proliferative rates, its ability to evade apoptosis, and its ability to invade healthy tissue. Therefore, it is crucial to explore new treatment options for GBM. This study investigated the potential anticancer activities of a new series of synthetic chalcones, which are natural compounds found in the biosynthesis of flavonoids in plants. Primary cell culture of glioblastoma (GBM1) from surgical resection was used to evaluate the effects of synthetic chalcones on viability, cell death, reactive oxygen species (ROS), mitochondrial membrane potential (ΔΨm), cell cycle, and invasion. One chalcone, Q1VA (at concentrations of 10, 50, and 100 μM for 24 h) induced cytotoxicity by increasing apoptosis levels and depolarizing the mitochondrial membrane, as evidenced by a TMRE assay. Further analysis using the molecular fluorescent probe H2DCFDA indicated that the increased levels of reactive oxygen species (ROS) might be linked to altered mitochondrial membrane potential and cell death. Furthermore, viable cells were observed to be delayed in the cell cycle, primarily in the M phase, and the invasion process was reduced. The findings of this study indicate that Q1VA is a potential adjuvant therapeutic agent for GBM due to its significant antitumor effects. If its safety and efficacy can be confirmed in animal models, Q1VA may be considered for clinical trials in humans. However, additional research is required to determine the optimal dosage, treatment schedule, and potential side effects of Q1VA.

The Application of CAR-T Cell Therapy

Cancer is undoubtedly the number one killer in today's society. Traditional surgical treatment methods have their own limitations, especially in the treatment of end-stage or hematological tumors. Emerging immunotherapy is an unprecedented breakthrough technology in cancer treatment. For example, PD-1/PD-L1 and CAR-T immunotherapy. CAR-T has been proposed for many years, it is only in the last few years that it has been improved and applied in the clinic. Its effectiveness in the treatment of cancer in hematology is encouraging. For example, it has a great curative impact in the acute leukemia, in the field of non-Hodgkin lymphoma ,it is also recognized as one of the most prospective and developed tumor treatments. Clinical application of CAR-T has attracted extensive attention. This therapy is characterized by the ability to detect tumor-associated antigens preferentially detected by T cells, which has a significant anti-tumor effect. This article will focus on HCC, list the existing HCC CAR-T treatment targets and briefly describe associated clinical research.

Loss of BLK expression as a potential predictor of poor prognosis and immune checkpoint blockade response in NSCLC and contribute to tumor progression

BackgroundImmune checkpoint blockade (ICB) has been proved to have significant anti-tumor effect in the clinical treatment of non-small cell lung cancer (NSCLC). Therefore, biomarkers predicting ICB response can provide better treatment for patients with NSCLC. MethodsDifferential expression genes (DEGs) were identified by ImmuCellAI database. Copy number alteration (CNA) was analyzed by cBioPortal. The predicted efficiency of 4 genes on cancer immunotherapy was assessed by ROC analysis. The survival value of BLK was analyzed by Kaplan-Meier plotter and Prognoscan analysis. Clinical significance of BLK IHC-TMA score in NSCLC was also explored. The CCK-8 assay, wound healing assay, western blot assay in vitro and subcutaneous xenograft experiments in vivo were used for investigating the functions of BLK. The RNA-sequencing were performed to screen BLK regulated genes and conducted for GO/KEGG enrichment analysis. The transcriptional regulatory factor of BLK promoter region was predicted by ChIP-seq analysis. Results39 common DEGs between ICB Response (R) group and No Response (NR) group with NSCLC were identified, in which the CNA frequency of BLK deletion (> 6%) was found. The predicted efficiency of BLK on immunotherapy was performed best in NSCLC (AUC>0.7). Low expression of BLK was related to NSCLC with significantly poor prognosis. BLK overexpression can inhibit growth of NSCLC via activating apoptosis pathway, inhibiting the G2M checkpoint and Glycolysis pathway. The enrichment analysis indicated that BLK regulated genes related to oncogenic potential in NSCLC. Besides, BLK expression was inhibited via H3K27me3 modification in A549 and H1299 cells. BLK mRNA level was negatively correlated with methylation and positively correlated with the tumor purity in NSCLC. ConclusionOur study provides strong evidence that low expression of BLK may serve as a biomarker for poor prognosis in NSCLC, while response to ICB therapy and contributes to NSCLC tumor progression.

Abstract LB021: KN-052, a novel PDL1/OX40 bispecific antibody, exhibits potent antitumor efficacy

Abstract KN052 is a recombinant PDL1/OX40 bispecific antibody which can block PDL1 and PD1/CD80 pathway and active the OX40 signal pathway at the same time. Inhibited PDL1 can block cancer cells to evade T-cell-mediated immune responses and restores T-cell activation and antitumor responses. On the other hand, biding to OX40 which normally expressed on Treg cells can induce ADCC effect and kill the Treg cells. There is a synergistic effect between the blocking of PDL1 pathway and the activation of OX40 signal pathway in cell base assay. PBMCs from four healthy donors showed significant T cell activation effect under the stimulation of superantigen SEB, and the activity of PBMCs from three healthy donors was significantly stronger than that of two single target control antibodies alone and in combination. The anti-tumor activity of KN052 was evaluated by using hPD-L1/hOX40 humanized mouse with MC38 MCA205 syngeneic model. Significant anti-tumor effects were observed in both models in a dose-dependent manner. The HNSTD (highest non-severely toxic dose) of KN052 was determined as 30mg/kg in cynomolgus monkeys. These preclinical data demonstrated acceptable PK and safety profile of KN052 and indicated its potential in a variety of tumors. Citation Format: Ting Xu, Pilin Wang, Yang-Xin Fu, Kangping Guo, Jianjian Peng. KN-052, a novel PDL1/OX40 bispecific antibody, exhibits potent antitumor efficacy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr LB021.

Abstract LB012: Claudin-1 is a driver and therapeutic target for cholangiocarcinoma

Abstract Introduction: Cholangiocarcinoma (CCA) shows an alarming rise in incidence and mortality with unsatisfactory treatment options. Claudin-1 (CLDN1), a member of the tight junction family, is a transmembrane protein mediating cell stemness, plasticity and signaling. The functional role of CLDN1 as a therapeutic target for CCA is unknown. We have previously developed highly specific monoclonal antibodies (mAb) targeting exposed non-junctional CLDN1 exhibiting an excellent safety profile in non-human primates (Roehlen, Saviano et al. Science Translational Medicine 2022). Here, we aimed to explore the role of CLDN1 as an oncogenic driver and therapeutic target for CCA. Methods: Comprehensive CLDN1 expression analyses in patient tissues were performed to evaluate CLDN1 as a therapeutic target. Proof-of-concept studies using CLDN1 mAbs were performed in state-of-the-art mouse CDX and PDX models including models for advanced metastatic disease. Single-cell RNA sequencing and proteomics were applied to investigate tumor cell fate and signaling in vivo and ex vivo models. Results: Comprehensive analyses of CLDN1 protein and RNA expression in CCA patient tissues revealed a marked and significant upregulation of CLDN1 in CCA. Single-cell RNA sequencing of the CCA microenvironment revealed strong expression in tumor cells showing EMT, cell cycle and interferon response signature, uncovering CLDN1 as a therapeutic target. Targeting exposed CLDN1 by highly specific mAbs resulted in a significant and robust antitumoral effect in vivo across CDX and PDX models for intra- and extrahepatic CCA including advanced metastatic disease. Functional studies in cell-based models of CCA showed that CLDN1 mAbs markedly and significantly suppressed migration and invasion of tumor cells. Mechanistically, treatment with CLDN1 mAb suppressed Notch1, Src, and Hippo-YAP signaling - key signal transduction pathways implicated in CCA development and progression. Conclusion: Collectively, these results support an important functional role for CLDN1 in CCA pathogenesis and provide robust pre-clinical proof-of-concept for CLDN1-specific mAbs to treat CCA, setting the stage for its clinical development. Citation Format: Marion Muller, Zeina Nehme, Emilie Crouchet, Frank Jühling, Natascha Röhlen, Patrick Pessaux, Emanuele Felli, Lipika Goyal, Markus Meyer, Roberto Iacone, Alberto Toso, Luigi Manenti, Patrice Laquerriere, Aïna Venkatasamy, Nabeel Bardeesy, Catherine Schuster, Laurent Mailly, Thomas F. Baumert. Claudin-1 is a driver and therapeutic target for cholangiocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr LB012.

A second-generation CD38-CAR-T cell for the treatment of multiple myeloma.

Multiple myeloma (MM) is an aggressive plasma cell malignancy, causing a number of deaths worldwide every year. Chimeric antigen receptor (CAR) transduced T-cell therapy has been a promising immunotherapy against hematological malignancies. In this study, we developed a second-generation CAR construct and generated CAR-T cells targeting CD38 molecule. Then effects of CAR-T cells against MM cell lines were evaluated. CD38-CAR-T cells showed higher cytotoxicity to MM cell lines and primary MM cells than that of control T cells in vitro. Over 50% MM1.s and RPMI8226 cells were killed by CAR-T cells even at effector to target ratio of 1:100. CAR-T cells also showed an enhanced cytotoxicity against primary MM cells. CAR-T cells could be activated and produced a variety of cytokines in a target-dependent manner. In vivo test indicated that CAR-T cells also showed significant antitumor effect on xenograft mice models. These results indicated a promising therapeutic strategy of CD38-CAR-T cells against MM.

Ablation of Gap Junction Protein Improves the Efficiency of Nanozyme-Mediated Catalytic/Starvation/Mild-Temperature Photothermal Therapy.

Reactive oxygen species (ROS)-mediated tumor catalytic therapy is typically hindered by gap junction proteins that form cell-to-cell channels to remove cytotoxic ROS, thereby protecting tumor cells from oxidative damage. Herein, a multifunctional nanozyme, FePGOGA, is designed and prepared by Fe(III)-mediated oxidative polymerization (FeP), followed by glucose oxidase (GOx) and GAP19 co-loading through electrostatic and π-π interactions. The FePGOGA nanozyme exhibits excellent cascade peroxidase- and glutathione-oxidase-like activities that efficiently catalyze hydrogen peroxide conversion to hydroxyl radicals and convert reduced glutathione to oxidized glutathione disulfide. The loaded GOx starves the tumors and aggravates tumor oxidative stress through glucose decomposition, while GAP19 peptides block the hemichannels by inducing degradation of Cx43, thus increasing the accumulation of intracellular ROS, and decreasing the transport of intracellular glucose. Furthermore, the ROS reacts with primary amines of heat shock proteins to destroy their structure and function, enabling tumor photothermal therapy at the widely sought-after mild temperature (mildPTT, ≤45°C). In vivo experiments demonstrate the significant anti-tumor effects of FePGOGA on cal27 xenograft tumors under near-infrared light irradiation. This study demonstrates the successful ablation of gap junction proteins to overcome resistance to ROS-mediated therapy, providing a regulator to suppress tumor self-preservation during tumor starvation, catalytic therapy, and mildPTT. This article is protected by copyright. All rights reserved.

Abstract 3991: NOS inhibition enhances docetaxel-mediated anti-tumor effect in obese mice with triple negative breast cancer

Abstract Purpose of the study: To evaluate the role of obesity in tumor progression and tumor microenvironment (TME) dynamic after the inhibition of nitric oxide synthase (NOS) in syngeneic murine models engrafted with triple negative breast cancer (TNBC) tumors. For this study, we wanted to deepen the results of our recently completed phase I/II clinical trial, where treatment with NG-methyl-L-arginine (L-NMMA, a pan-NOS inhibitor) increased the response rate to chemotherapy (docetaxel) in obese metastatic TNBC (ER-/PR-/HER2-) patients to 86% vs. 60% in normal weight individuals. TME analysis from responders revealed a neutrophil phenotype shift from protumor N2 to antitumor N1. We thus hypothesize that combined treatment with L-NMMA and docetaxel enhances antitumor effect by modulating TME in obese mice with TNBC. Experimental procedures: 3-week old female C57BL/6 mice were fed for 10 weeks either with high fat diet (HFD) or normal diet (ND). At week 13, TNBC mouse E0771 tumor cells were injected into the mice mammary fat pad. Once tumors reached 100 mm3, the animals were randomized to four groups: vehicle; docetaxel; L-NMMA; and docetaxel plus L-NMMA treatment. Tumor volume was measured throughout the experiment and growth rate was compared between groups at the end of treatment. Blood, tumor and perigonadal white adipose tissue (pgWAT) were collected. Cytokines and nitrite/nitrate levels (NO2-/NO3-, a NO indicator) were measured from blood and conditioned media (CM) from pgWAT using appropriate kits. Tumor immune cell infiltration was evaluated by immunohistochemistry. GraphPad software was used for statistical analysis and P-values <0.05 were considered to describe statistically significant differences between groups. Results: Tumor growth rate was significantly higher in HFD mice compared to ND mice. Treatment with the docetaxel/L-NMMA combination significantly slowed tumor growth in HFD mice (p=0.015), and showed a similar trend in ND mice (p=0.92) vs. the corresponding vehicle-treated groups. The reduction of tumor growth was significantly higher in HFD mice vs. ND mice (median of differences -2.0, p=0.031). HFD mice presented higher levels of pro-inflammatory cytokines, [IL-1b (p=0.011), IL-6 (p<0.0001) and TNFa (p<0.0001)] vs ND mice in pgWAT CM, as well as increased levels of NO2-/NO3- and expression of iNOS in tumors and in perigonadal adipose tissue. Conclusion: HFD mice had a pro-inflammatory profile with a significantly faster tumor growth and higher expression of iNOS in tumor and adipose tissues. Treatment with the docetaxel/L-NMMA combination resulted in a more significant anti-tumor effect in HFD mice, likely through remodeling of TME. Spatial analysis, including CODEX and immunophenotyping are being conducted to determine the TME influence in obesity associated TNBC and the effect of NOS inhibition. Citation Format: Ivonne Uzair, Kai Sun, Ann Anselme, Wei Qian, Jianying Zhou, Roberto Rosato, Jenny Chang. NOS inhibition enhances docetaxel-mediated anti-tumor effect in obese mice with triple negative breast cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3991.

Abstract 6315: Human granzyme B fusions targeting VEGFR on tumor cells and activated vasculature

Abstract VEGF121 is a naturally-occurring splice variant that binds to VEGF receptors R-1 and R-2, which are over-expressed on the endothelium of tumor vasculature but not normal vasculature, as well as several tumor cells. While anti-VEGF therapy is a key therapeutic in several cancer treatment regimens, none of the current therapeutics (bevacizumab, VEGF-trap, tyrosine kinase inhibitors) are directly cytotoxic against tumor cells. The serine protease Granzyme B (GrB) is a key effector in immune-mediated cell killing by inducing apoptosis through both caspase-dependent and -independent mechanisms. We previously reported the development and characterization of a fusion protein composed of GrB and VEGF121 (GrB/VEGF121). Here, we report on GrB-Fc-VEGF121, a fusion protein that incorporates a human IgG heavy chain Fc fragment for dimerization which increases the molecular weight and improves in vivo circulation and targeting potential. GrB-Fc-VEGF121 was expressed in HEK-293E cells under serum-free conditions and purified from the conditioned medium with a final yield of approximately 40 mg/L. The enzymatic activity of GrB in GrB-Fc-VEGF121 was comparable to that of commercially available human GrB. In vitro studies of GrB-Fc-VEGF121 showed cytotoxicity in the nanomolar range against tumor and endothelial cell lines expressing high levels of VEGFR-1 or VEGFR-2. Receptor-negative cells demonstrated IC50 levels in the high micromolar range. Immunofluorescence and confocal microscopy demonstrated that GrB-Fc-VEGF121 readily internalized into VEGFR-2+ tumor cells and endothelial cells within 2 hours of treatment while untargeted GrB did not internalize, suggesting internalization was receptor-mediated. Treatment of VEGFR-2+ endothelial and tumor cells at the IC50 dose resulted in >50% cell death via apoptosis and/or necrosis within 48 h. Ex vivo serum stability of GrB-Fc-VEGF121 indicated a gradual protein loss of GrB-Fc-VEGF121, with an overall stability of about 50% over 96 hours. No toxicity was observed in BALB/c mice treated with a total 475 mg/kg given IP every other day over 5 doses, indicating that the maximum tolerated dose of GrB-Fc-VEGF121 exceeds this dose level. In vivo efficacy studies in an OVCAR8 tumor xenograft model with GrB-Fc-VEGF121 (100 mg/kg over 5 doses) resulted in significant growth inhibition of established tumors compared to vehicle controls. We observed a significant decrease in the number of CD31+ blood vessels and Ki-67+ proliferating tumor cells in treated tumors compared to controls. Thus, GrB-Fc-VEGF121 has significant anti-tumor effects in vivo with virtually no toxicity against normal tissues at doses 4-5 times higher than therapeutic levels. This tumor- and vascular-targeting agent appears to have significant potential as a new class of targeted therapeutic agents with a unique mechanism of action. Research conducted, in part, by the Clayton Foundation for Research. Citation Format: Khalid A. Mohamedali, Lawrence H. Cheung, Ana Alvarez-Cienfuegos, Walter N. Hittelman, Michael G. Rosenblum. Human granzyme B fusions targeting VEGFR on tumor cells and activated vasculature [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6315.