ACOX1 deficiency-induced lipid metabolic disorder facilitates chronic interstitial fibrosis development in renal allografts.

Chronic interstitial fibrosis presents a significant challenge to the long-term survival of transplanted kidneys. Our research has shown that reduced expression of acyl-coenzyme A oxidase 1 (ACOX1), which is the rate-limiting enzyme in the peroxisomal fatty acid ß-oxidation pathway, contributes to the development of fibrosis in renal allografts. ACOX1 deficiency leads to lipid accumulation and excessive oxidation of polyunsaturated fatty acids (PUFAs), which mediate epithelial-mesenchymal transition (EMT) and extracellular matrix (ECM) reorganization respectively, thus causing fibrosis in renal allografts. Furthermore, activation of Toll-like receptor 4 (TLR4)-nuclear factor kappa-B (NF-κB) signaling induced ACOX1 downregulation in a DNA methyltransferase 1 (DNMT1)-dependent manner. Overconsumption of PUFA resulted in endoplasmic reticulum (ER) stress, which played a vital role in facilitating ECM reorganization. Supplementation with PUFAs contributed to delayed fibrosis in a rat model of renal transplantation. The study provides a novel therapeutic approach that can delay chronic interstitial fibrosis in renal allografts by targeting the disorder of lipid metabolism.

Anti-thrombotic Effects Mediated by a Novel Dual-Target Peptide Inhibiting Both Platelet Aggregation and Thrombin Activity without Causing Bleeding.

BACKGROUND: Classical anticoagulants and antiplatelets are associated with high frequencies of bleeding complications or treatment failure when used as single agents. Thrombin plays an important role in the blood coagulation system. GP IIb/IIIa is the central receptor of platelets, which can recognize the Arg-Gly-Asp (RGD) sequence and activate platelets. MATERIAL AND METHODS: Molecular simulation and homology modeling were performed to design a novel dual-target anticoagulant short peptide (PTIP ). The activities of PTIP on coagulation and platelet in vitro were analyzed. The antithrombotic activity of PTIP was determined by pulmonary thromboembolism model, ferric chloride injury model and arteriovenous bypass thrombosis model. Bleeding effect and toxicity of PTIP were evaluated. RESULTS: We have constructed a novel dual-target peptide (PTIP) based on the direct thrombin inhibitor peptide (DTIP). PTIP was expressed at high levels in Pichia pastoris. PTIP interfered with thrombin-mediated coagulation and ADP-induced platelet aggregation in vitro. When injected intravenously or subcutaneously, PTIP showed potent and dose-dependent extension of aPTT and PT which were similar to DTIP; but only PTIP was capable of inhibiting platelet aggregation. PTIP (1.0 mg/kg) decelerated thrombosis formation in venous and arterial vessels induced by FeCl3 injury. PTIP (1.0 mg/kg) also prevented deep venous thrombosis and increased the survival rate associated with pulmonary thromboembolism. And PTIP effectively reduced thrombus length in arteriovenous bypass thrombosis model. Moreover, the antithrombotic dose of PTIP could not induce bleeding. CONCLUSION: These data establish that PTIP represents a novel antithrombotic agent whose effects involve both inhibition of platelet activation and reduction of fibrin generation. And PTIP not only can be used in venous thrombosis and arterial thrombosis, it can also replace the combined treatment of antiplatelet and anticoagulant drugs in thrombotic diseases.

Peroxisome proliferator-activated receptors: A key link between lipid metabolism and cancer progression.

Lipids represent the essential components of membranes, serve as fuels for high-energy processes, and play crucial roles in signaling and cellular function. One of the key hallmarks of cancer is the reprogramming of metabolic pathways, especially abnormal lipid metabolism. Alterations in lipid uptake, lipid desaturation, de novo lipogenesis, lipid droplets, and fatty acid oxidation in cancer cells all contribute to cell survival in a changing microenvironment by regulating feedforward oncogenic signals, key oncogenic functions, oxidative and other stresses, immune responses, or intercellular communication. Peroxisome proliferator-activated receptors (PPARs) are transcription factors activated by fatty acids and act as core lipid sensors involved in the regulation of lipid homeostasis and cell fate. In addition to regulating whole-body energy homeostasis in physiological states, PPARs play a key role in lipid metabolism in cancer, which is receiving increasing research attention, especially the fundamental molecular mechanisms and cancer therapies targeting PPARs. In this review, we discuss how cancer cells alter metabolic patterns and regulate lipid metabolism to promote their own survival and progression through PPARs. Finally, we discuss potential therapeutic strategies for targeting PPARs in cancer based on recent studies from the last five years.

Targeted changes in blood lipids improves fibrosis in renal allografts.

BACKGROUND: Chronic interstitial fibrosis is the primary barrier against the long-term survival of transplanted kidneys. Extending the lifespan of allografts is vital for ensuring the long-term health of patients undergoing kidney transplants. However, few targets and their clinical applications have been identified. Moreover, whether dyslipidemia facilitates fibrosis in renal allograft remains unclear. METHODS: Blood samples were collected from patients who underwent kidney transplantation. Correlation analyses were conducted between the Banff score and body mass index, and serum levels of triacylglycerol, total cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol. A rat model of renal transplantation was treated with the lipid-lowering drug, fenofibrate, and kidney fibrosis levels were determined by histochemical staining. Targeted metabolomic detection was conducted in blood samples from patients who underwent kidney transplantation and were divided into fibrotic and non-fibrotic groups. Rats undergoing renal transplantation were fed either an n-3 or n-6 polyunsaturated fatty acid (PUFA)-enriched diet. Immunohistochemical and Masson's trichrome staining were used to determine the degree of fibrosis. RESULTS: Hyperlipidemia was associated with fibrosis development. Treatment with fenofibrate contributed to improve fibrosis in a rat model of renal transplantation. Moreover, n-3 PUFAs from fibrotic group showed significant downregulation compared to patients without fibrotic renal allografts, and n-3 PUFAs-enriched diet contributed to delayed fibrosis in a rat model of renal transplantation. CONCLUSIONS: This study suggests that hyperlipidemia facilitates fibrosis of renal allografts. Importantly, a new therapeutic approach was provided that may delay chronic interstitial fibrosis in transplanted kidneys by augmenting the n-3 PUFA content in the diet.

The connection between tricarboxylic acid cycle enzyme mutations and pseudohypoxic signaling in pheochromocytoma and paraganglioma.

Pheochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumors originating from chromaffin cells, holding significant clinical importance due to their capacity for excessive catecholamine secretion and associated cardiovascular complications. Roughly 80% of cases are associated with genetic mutations. Based on the functionality of these mutated genes, PPGLs can be categorized into distinct molecular clusters: the pseudohypoxia signaling cluster (Cluster-1), the kinase signaling cluster (Cluster-2), and the WNT signaling cluster (Cluster-3). A pivotal factor in the pathogenesis of PPGLs is hypoxia-inducible factor-2α (HIF2α), which becomes upregulated even under normoxic conditions, activating downstream transcriptional processes associated with pseudohypoxia. This adaptation provides tumor cells with a growth advantage and enhances their ability to thrive in adverse microenvironments. Moreover, pseudohypoxia disrupts immune cell communication, leading to the development of an immunosuppressive tumor microenvironment. Within Cluster-1a, metabolic perturbations are particularly pronounced. Mutations in enzymes associated with the tricarboxylic acid (TCA) cycle, such as succinate dehydrogenase (SDHx), fumarate hydratase (FH), isocitrate dehydrogenase (IDH), and malate dehydrogenase type 2 (MDH2), result in the accumulation of critical oncogenic metabolic intermediates. Notable among these intermediates are succinate, fumarate, and 2-hydroxyglutarate (2-HG), which promote activation of the HIFs signaling pathway through various mechanisms, thus inducing pseudohypoxia and facilitating tumorigenesis. SDHx mutations are prevalent in PPGLs, disrupting mitochondrial function and causing succinate accumulation, which competitively inhibits α-ketoglutarate-dependent dioxygenases. Consequently, this leads to global hypermethylation, epigenetic changes, and activation of HIFs. In FH-deficient cells, fumarate accumulation leads to protein succination, impacting cell function. FH mutations also trigger metabolic reprogramming towards glycolysis and lactate synthesis. IDH1/2 mutations generate D-2HG, inhibiting α-ketoglutarate-dependent dioxygenases and stabilizing HIFs. Similarly, MDH2 mutations are associated with HIF stability and pseudohypoxic response. Understanding the intricate relationship between metabolic enzyme mutations in the TCA cycle and pseudohypoxic signaling is crucial for unraveling the pathogenesis of PPGLs and developing targeted therapies. This knowledge enhances our comprehension of the pivotal role of cellular metabolism in PPGLs and holds implications for potential therapeutic advancements.

Mapping the tumor microenvironment in clear cell renal carcinoma by single-cell transcriptome analysis.

Introduction: Clear cell renal cell carcinoma (ccRCC) is associated with unfavorable clinical outcomes. To identify viable therapeutic targets, a comprehensive understanding of intratumoral heterogeneity is crucial. In this study, we conducted bioinformatic analysis to scrutinize single-cell RNA sequencing data of ccRCC tumor and para-tumor samples, aiming to elucidate the intratumoral heterogeneity in the ccRCC tumor microenvironment (TME). Methods: A total of 51,780 single cells from seven ccRCC tumors and five para-tumor samples were identified and grouped into 11 cell lineages using bioinformatic analysis. These lineages included tumor cells, myeloid cells, T-cells, fibroblasts, and endothelial cells, indicating a high degree of heterogeneity in the TME. Copy number variation (CNV) analysis was performed to compare CNV frequencies between tumor and normal cells. The myeloid cell population was further re-clustered into three major subgroups: monocytes, macrophages, and dendritic cells. Differential expression analysis, gene ontology, and gene set enrichment analysis were employed to assess inter-cluster and intra-cluster functional heterogeneity within the ccRCC TME. Results: Our findings revealed that immune cells in the TME predominantly adopted an inflammatory suppression state, promoting tumor cell growth and immune evasion. Additionally, tumor cells exhibited higher CNV frequencies compared to normal cells. The myeloid cell subgroups demonstrated distinct functional properties, with monocytes, macrophages, and dendritic cells displaying diverse roles in the TME. Certain immune cells exhibited pro-tumor and immunosuppressive effects, while others demonstrated antitumor and immunostimulatory properties. Conclusion: This study contributes to the understanding of intratumoral heterogeneity in the ccRCC TME and provides potential therapeutic targets for ccRCC treatment. The findings emphasize the importance of considering the diverse functional roles of immune cells in the TME for effective therapeutic interventions.

Simultaneous Generation of Ammonia during Nitrile Waste Gas Purification over a Silver Single-Atom-Doped Ceria Catalyst.

Catalytic elimination of toxic nitrile waste gas is of great significance for preserving the atmospheric environment, but achieving resource utilization during its destruction has been less explored. Herein, this study proposed a universal strategy for nitrile waste gas purification and NH3 generation simultaneously. The developed silver single-atom-doped ceria nanorod (Ag1/R-CeO2) was endowed with near complete mineralization and around 90% NH3 yield at 300-350 °C for the catalytic oxidation of both acetonitrile and acrylonitrile. The introduction of the Ag single atom created more surface oxygen vacancies, thereby promoting water activation to form abundant surface hydroxyl groups. As a benefit from this, the hydrolysis reaction of nitrile to generate NH3 was accelerated. Meanwhile, the electron transfer effect from the Ag atom to Ce and hydroxyl species facilitated NH3 desorption, which inhibited the oxidation of NH3. Moreover, the increased surface oxygen vacancies also promoted the mineralization of hydrolysis carbonaceous intermediates to CO2. In contrast, the Ag nanoparticle-modified sample possessed stronger reducibility and NH3 adsorption, leading to the excessive oxidation of NH3 to N2 and NOx. This work provided a useful guidance for resourceful purification of nitrile waste gas.

Photocatalytic Oxidative Coupling of Methane over Au1 Ag Single-Atom Alloy Modified ZnO with Oxygen and Water Vapor: Synergy of Gold and Silver.

C-H dissociation and C-C coupling are two key steps in converting CH4 into multi-carbon compounds. Here we report a synergy of Au and Ag to greatly promote C2 H6 formation over Au1 Ag single-atom alloy nanoparticles (Au1 Ag NPs)-modified ZnO catalyst via photocatalytic oxidative coupling of methane (POCM) with O2 and H2 O. Atomically dispersed Au in Au1 Ag NPs effectively promotes the dissociation of O2 and H2 O into *OOH, promoting C-H activation of CH4 on the photogenerated O- to form *CH3 . Electron-deficient Au single atoms, as hopping ladders, also facilitate the migration of electron donor *CH3 from ZnO to Au1 Ag NPs. Finally, *CH3 coupling can readily occur on Ag atoms of Au1 Ag NPs. An excellent C2 H6 yield of 14.0 mmol g-1 h-1 with a selectivity of 79 % and an apparent quantum yield of 14.6 % at 350 nm is obtained via POCM with O2 and H2 O, which is at least two times that of the photocatalytic system. The bimetallic synergistic strategy offers guidance for future catalyst design for POCM with O2 and H2 O.

Role of extracellular vesicles in pathogenesis and therapy of renal ischemia-reperfusion injury.

Renal ischemia-reperfusion injury (RIRI) is a complex disorder characterized by both intrinsic damage to renal tubular epithelial cells and extrinsic inflammation mediated by cytokines and immune cells. Unfortunately, there is no cure for this devastating condition. Extracellular vesicles (EVs) are nanosized membrane-bound vesicles secreted by various cell types that can transfer bioactive molecules to target cells and modulate their function. EVs have emerged as promising candidates for cell-free therapy of RIRI, owing to their ability to cross biological barriers and deliver protective signals to injured renal cells. In this review, we provide an overview of EVs, focusing on their functional role in RIRI and the signaling messengers responsible for EV-mediated crosstalk between various cell types in renal tissue. We also discuss the renoprotective role of EVs and their use as therapeutic agents for RIRI, highlighting the advantages and challenges encountered in the therapeutic application of EVs in renal disease.

Photocatalytic Oxidative Coupling of Methane to Ethane Using Water and Oxygen on Ag3PO4-ZnO.

Photocatalytic oxidative coupling is an effective way of converting CH4 to high-value-added multi-carbon chemicals under mild conditions, where the breaking of the C-H bond is the main rate-limiting step. In this paper, the Ag3PO4-ZnO heterostructure photocatalyst was synthesized for photocatalytic oxidative coupling of methane (OCM) to C2H6. In addition, an excellent C2H6 yield (16.62 mmol g-1 h-1) and a remarkable apparent quantum yield (15.8% at 350 nm) at 49:1 CH4/Air and 20% RH are obtained, which is more than three times that of the state-of-the-art photocatalytic systems. Ag3PO4 improves the adsorption and dissociation ability of O2 and H2O, benefiting the formation of surface hydroxyl species. As a result, the C-H bond activation energy of CH4 on ZnO was obviously reduced. Meanwhile, the improved separation of photogenerated carriers on the Ag3PO4-ZnO heterostructure also accelerates the OCM process. Moreover, Ag nanoparticles (NPs) derived from Ag3PO4 reduction by photoelectrons promote the coupling of *CH3, which can inhibit the overoxidation of CH4 and increase C2H6 selectivity. This research provides a guide for the design of catalyst and reaction systems in the photocatalytic OCM process.

A novel recombinant human microplasminogen induced complete posterior vitreous detachment without morphological change of retina in juvenile rabbits.

Vitreomacular traction syndrome results from persistent vitreoretinal adhesions in the setting of partial posterior vitreous detachment (PVD). Vitrectomy and reattachment of retina is an effective therapeutic approach. The adhesion between vitreous cortex and internal limiting membrane (ILM) of the retina is stronger in youth, which brings difficulties to induce PVD in vitrectomy. Several clinical investigations demonstrated that intravitreous injection of plasmin before vitrectomy could reduce the risk of detachment. In our study, a novel recombinant human microplasminogen (rhµPlg) was expressed by Pichia pastoris. Molecular docking showed that the binding of rhµPlg with tissue plasminogen activator (t-PA) was similar to plasminogen, suggesting rh µPlg could be activated by t-PA to generate microplasmin (µPlm). Moreover, rhµPlg had higher catalytic activity than plasminogen in amidolytic assays. Complete PVD was found at vitreous posterior pole of 125 µg rhµPlg-treated eyes without morphological change of retina in juvenile rabbits via intraocular injection. Our results demonstrate that rhµPlg has a potential value in the treatment of vitreoretinopathy.

Key events in cancer: Dysregulation of SREBPs.

Lipid metabolism reprogramming is an important hallmark of tumor progression. Cancer cells require high levels of lipid synthesis and uptake not only to support their continued replication, invasion, metastasis, and survival but also to participate in the formation of biological membranes and signaling molecules. Sterol regulatory element binding proteins (SREBPs) are core transcription factors that control lipid metabolism and the expression of important genes for lipid synthesis and uptake. A growing number of studies have shown that SREBPs are significantly upregulated in human cancers and serve as intermediaries providing a mechanistic link between lipid metabolism reprogramming and malignancy. Different subcellular localizations, including endoplasmic reticulum, Golgi, and nucleus, play an indispensable role in regulating the cleavage maturation and activity of SREBPs. In this review, we focus on the relationship between aberrant regulation of SREBPs activity in three organelles and tumor progression. Because blocking the regulation of lipid synthesis by SREBPs has gradually become an important part of tumor therapy, this review also summarizes and analyzes several current mainstream strategies.

The role of MEOX1 in non-neoplastic and neoplastic diseases.

Targeted gene therapy has shown durable efficacy in non-neoplastic and neoplastic patients. Therefore, finding a suitable target has become a key area of research. Mesenchyme homeobox 1 (MEOX1) is a transcriptional factor that plays a significant role in regulation of somite development. Evidence indicates that abnormalities in MEOX1 expression and function are associated with a variety of pathologies, including non-neoplastic and neoplastic diseases. MEOX1 expression is upregulated during progression of most diseases and plays a critical role in maintenance of the cellular phenotypes such as cell differentiation, cell cycle arrest and senescence, migration, and proliferation. Therefore, MEOX1 may become an important molecular target and therapeutic target. This review will discuss the current state of knowledge on the role of MEOX1 in different diseases.

NLRP3 inflammasome: A potential therapeutic target to minimize renal ischemia/reperfusion injury during transplantation.

Renal transplantation is currently the best treatment option for patients with end-stage kidney disease. Ischemia/reperfusion injury (IRI), which is an inevitable event during renal transplantation, has a profound impact on the function of transplanted kidneys. It has been well demonstrated that innate immune system plays an important role in the process of renal IRI. As a critical component of innate immune system, Nod-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome has received great attention from scientific community over the past decade. The main function of NLRP3 inflammasome is mediating activation of caspase-1 and maturation of interleukin (IL)-1ß and IL-18. In this review, we summarize the associated molecular signaling events about NLRP3 inflammasome in renal IRI, and highlight the possibility of targeting NLRP3 inflammasome to minimize renal IRI during transplantation.

Stability of Eu(III)-silicate colloids: Effect of Eu content, pH, electrolyte and fulvic acid.

Dissolved silicic acid in the environment has strong affinity for actinides (An), but An(III)-silicate colloids have been scarcely investigated. In this study, Eu(III)-silicate colloids, an analogue to An(III)-silicate, were prepared and the aggregation kinetics of the colloids was investigated as a function of Eu content (Si/Eu molar ratio), pH, background electrolyte (NaCl, NaNO3, NaClO4, KCl and CsCl) and fulvic acid (FA). Results indicated that the colloids with higher Si/Eu molar ratio exhibited higher stability under the same conditions. The stability of the colloids increased with increasing aqueous pH (7.1-9.4) and decreasing ionic strength, and the inhibition effect of monovalent electrolytes on the colloid stability followed the order of Na+ < K+ < Cs+ and Cl- < NO3- < ClO4-. In addition, the presence of FA significantly increased the stability of the colloids. The dependence of the stability on the chemical conditions in all cases could be illustrated by DLVO theory. Disaggregation kinetics showed that the aggregation process of the colloids was not fully reversible, because a time-dependent size memory effect led to a bigger mean size of disaggregated colloids as compared to the initial ones. The present work provides detailed insight in the formation and stability of An(III)-silicate colloids under the alkaline conditions relevant to geological disposal of radioactive waste, which is critical for understanding the behavior of this type of colloids in the environment.

Cellular Senescence in Adrenocortical Biology and Its Disorders.

Cellular senescence is considered a physiological process along with aging and has recently been reported to be involved in the pathogenesis of many age-related disorders. Cellular senescence was first found in human fibroblasts and gradually explored in many other organs, including endocrine organs. The adrenal cortex is essential for the maintenance of blood volume, carbohydrate metabolism, reaction to stress and the development of sexual characteristics. Recently, the adrenal cortex was reported to harbor some obvious age-dependent features. For instance, the circulating levels of aldosterone and adrenal androgen gradually descend, whereas those of cortisol increase with aging. The detailed mechanisms have remained unknown, but cellular senescence was considered to play an essential role in age-related changes of the adrenal cortex. Recent studies have demonstrated that the senescent phenotype of zona glomerulosa (ZG) acts in association with reduced aldosterone production in both physiological and pathological aldosterone-producing cells, whereas senescent cortical-producing cells seemed not to have a suppressed cortisol-producing ability. In addition, accumulated lipofuscin formation, telomere shortening and cellular atrophy in zona reticularis cells during aging may account for the age-dependent decline in adrenal androgen levels. In adrenocortical disorders, including both aldosterone-producing adenoma (APA) and cortisol-producing adenoma (CPA), different cellular subtypes of tumor cells presented divergent senescent phenotypes, whereby compact cells in both APA and CPA harbored more senescent phenotypes than clear cells. Autonomous cortisol production from CPA reinforced a local cellular senescence that was more severe than that in APA. Adrenocortical carcinoma (ACC) was also reported to harbor oncogene-induced senescence, which compensatorily follows carcinogenesis and tumor progress. Adrenocortical steroids can induce not only a local senescence but also a periphery senescence in many other tissues. Therefore, herein, we systemically review the recent advances related to cellular senescence in adrenocortical biology and its associated disorders.

Curcumin inhibits prostate cancer progression by regulating the miR-30a-5p/PCLAF axis.

Curcumin has been shown to inhibit the growth of a variety of tumor cells. However, the biological functions of curcumin in prostate cancer (PCa) have not yet fully elucidated. The objective of the present study was to investigate the role of curcumin on the proliferation, migration, invasion and apoptosis of PCa cells and the underlying mechanism. Cell Counting Kit-8 and flow cytometry were used to detect the effects of curcumin at different concentrations on the proliferation and apoptosis of PCa cell lines, PC-3 and DU145. BrdU and Transwell assays, western blotting and reverse transcription-quantitative PCR were used to determine the effect of curcumin on cell proliferation, migration and invasion, apoptosis-related protein expression, and microRNA (miR)-30a-5p and PCNA clamp associated factor (PCLAF) expression, respectively. In addition, bioinformatics analysis and Pearson's correlation test were used to verify the relationship between miR-30a-5p and PCLAF. Curcumin was observed to impede the proliferation, migration and invasion of PCa cells, and promote their apoptosis in a time- and dose-dependent manner. Curcumin enhanced miR-30a-5p expression and inhibited PCLAF expression; furthermore, there was a negative correlation between miR-30a-5p and PCLAF expression in PCa tissues. In addition, transfection of miR-30a-5p inhibitors partially reversed the function of curcumin on cell proliferation, migration, invasion and apoptosis. Overall, curcumin suppressed the malignant biological behaviors of PCa cells by regulating the miR-30a-5p/PCLAF axis.

Development of bispecific anti-c-Met/PD-1 diabodies for the treatment of solid tumors and the effect of c-Met binding affinity on efficacy.

Although the blockade of the programmed cell death protein 1/programmed cell death ligand 1 (PD-1/PD-L1) pathway has become a promising treatment strategy for several types of cancers, the constitutive activation of c-Met in tumors may cause a low overall response rate to PD-1 inhibitors. Increasing evidence indicates that the dual inhibition of c-Met and PD-1 could improve the efficacy of anti-PD-1/PD-L1 monoclonal antibodies for tumor immunotherapy. In this study, we developed two bispecific single-chain diabodies targeting c-Met and PD-1 for the treatment of solid tumors based on protein homology modeling, and we identified that the binding affinity of diabody-mp to c-Met was 50-folds higher than that of diabody-pm. The results of in vitro studies revealed that both diabodies suppressed HGF-induced proliferation, migration, and invasion of tumor cells, inhibiting the activation of c-Met signaling by antagonizing HGF binding to c-Met. Moreover, they promoted T cell activation by blocking the PD-1 pathway, mediating tumor cellular cytotoxicity through T cell engagement. In vivo studies with mice models demonstrated that diabody-mp exhibited higher therapeutic efficacy than other structural antibodies, greatly enhancing the survival of c-Met-positive tumor-bearing mice compared to single or combined c-Met and PD-1 blockade therapy. Furthermore, diabody-mp, which had a higher c-Met binding affinity, showed better anti-tumoral activity than diabody-pm, which had a lower c-Met binding affinity. In conclusion, bispecific anti-PD-1/c-Met diabody-mp, with high c-Met-associated affinity, inhibited tumor growth by activating T cells, suggesting its therapeutic potential for c-Met-positive solid tumors.

Dual-function chimeric antigen receptor T cells targeting c-Met and PD-1 exhibit potent anti-tumor efficacy in solid tumors.

Purpose Programmed cell death 1 (PD-1), which is upregulated under the continuous induction of the tumor microenvironment, causes chimeric antigen receptor (CAR)-T cell hypofunction via interaction with programmed death ligand 1 (PD-L1). This study aimed to construct CAR-T cells that are resistant to PD-1 inhibition to improve the effect of CAR-T cells in solid tumors. Methods We constructed a type of dual-function CAR-T cell that targets tumor-associated antigen c-Met and blocks the binding of PD-1 with PD-L1. The expression of c-Met, PD-L1, and inhibitory receptors was measured using flow cytometry. The cytotoxicity, cytokine release, and differentiation level of CAR-T cells were determined using lactate dehydrogenase release assay, enzyme-linked immunosorbent assay, and flow cytometry, respectively. The levels of p-Akt, p-MAPK, caspase-3, and Bcl2 were detected by western blot. The in vivo anti-tumor effect was evaluated using tumor xenograft models. Results Dual-function CAR-T cells could mediate enhanced active signals upon encountering target antigens and had targeted cytotoxicity to target cells. However, the cytotoxicity of c-Met-CAR-PD-1+ T cells was impaired due to the interaction of PD-1 with PD-L1. By blocking the binding of PD-1 and PD-L1, the novel dual-function CAR-PD-1+ T cells could maintain cytotoxicity to PD-L1+ tumor cells. In tumor tissue, the dual-function CAR-T cells showed lower inhibitory receptor expression and lower differentiation characteristics, which resulted in potent anti-tumor effects and prolonged survival in PD-L1+ tumor xenograft models compared to single-target CAR-T cells. Conclusion These results confirm that the novel dual-function CAR-T cells exhibit stronger anti-tumor activity against solid tumors than traditional single-target CAR-T cells and present a new approach that enhance the activity of CAR-T cells in solid tumors.