Valosin-containing protein (VCP), a conserved AAA ATPase hexamer, participates in multiple biological processes including ERAD, ubiquitin-dependent degradation by extracting misfolded proteins for proteasomal degradation. Although its interactions with cofactors are well-characterized, and its dysregulation is implicated in multisystem proteinopathy, amyotrophic lateral sclerosis, and cancer, the tissue-specific VCP interactomes underlying its functional versatility remain elusive. Here, we generated HA-N-tagged VCP knock-in mice via CRISPR/Cas9 strategy and performed affinity purification coupled with data-independent acquisition (DIA) mass spectrometry to systematically profile VCP interactors across eight mouse tissues, yielding a high-confidence dataset. We identified 923 robust VCP-binding partners, including established interactors (UBX2B, UFD1, proteasomal subunits) and novel candidates implicated in energy metabolism (TCA cycle, oxidative phosphorylation) and protein quality control (proteasome, ERAD). Notably, we validated the interaction of VCP to two hepatic candidate proteins, DAXX and PRKAG2 (AMPK γ2 regulatory subunit), using HepG2 cells. This study establishes the first in vivo atlas of the VCP interaction network, providing mechanistic insights into its tissue-specific roles and highlighting potential therapeutic avenues for VCP-related disorders.

ABSTRACT:Erythropoiesis, the process of red blood cell production, is highly dependent on iron uptake by transferrin and its receptor, transferrin receptor 1 (TfR1). However, the mechanisms governing the proper recycling of TfR1 in relation to cellular iron demands remain elusive. Here, we identify human TMEM187, a Golgi transmembrane protein of unknown function, as a novel negative regulator of erythropoiesis. Lack of TMEM187 in cell models initiates erythropoiesis without the normal induction protocol and accelerates iron uptake. Following the induction protocol, TMEM187 ablation leads to premature erythroid maturation, resulting in early phosphatidylserine ectopia and cell membrane fragility, hallmarks of cellular senescence that render the cells susceptible to macrophage recognition and phagocytosis. In zebrafish embryos, tmem187 deletion leads to enhanced early erythropoiesis, although this phenotype is later compensated, whereas hematopoietic stem cell expression of human TMEM187 in mice, which lack a homologous gene endogenously, results in compromised erythropoiesis and moderate anemia. Mechanistically, we demonstrate that TMEM187 interacts with RAB11A to restrain endosomal recycling by interfering with RAB11A-GRAB association, involved with endosomal vesicle back to the plasma membrane, that activates RAB11A. Consequently, TMEM187 modulates TfR1 recycling to the cell membrane to fine-tune iron uptake efficiency for erythropoiesis. Our findings reveal a novel modulatory pathway in which TMEM187 plays a crucial role in regulating erythroid differentiation, maturation, and senescence, providing a previously unexplored perspective on TMEM187's physiological function.

Autophagy-mediated anoikis resistance plays a critical role in the initiation of tumor metastasis. Therefore, we investigated the role and mechanism of anoikis resistance mediated by free fatty acids (FFAs) derived from lipophagy in highly invasive clear cell renal cell carcinoma (ccRCC). Here, we found that the highly invasive ccRCC cell line Himi exhibited enhanced resistance to anoikis and elevated lipophagy levels. The increased lipophagy observed in Himi ccRCC cells contributed to their resistance to anoikis. The nonreceptor tyrosine kinase Src was significantly upregulated in Himi cells cultured under suspension conditions and in patients with poor prognoses. The underlying mechanism revealed that the FFAs released from lipophagy activated the phosphorylated Tyr419 site of Src, thereby promoting ccRCC invasion, facilitating epithelial-mesenchymal transition (EMT), enhancing angiogenesis, and conferring resistance to anoikis. Therefore, the present study revealed that FFAs generated from the degradation of lipid droplets via lipophagy enhanced resistance to anoikis by activating the phosphorylated Tyr419 site of Src in highly invasive ccRCC.

KRAS mutations are major drivers of human cancers, yet how distinct mutations rewire protein interactions and metabolic pathways to promote tumorigenesis remains poorly understood. To address this, we systematically mapped the protein interaction networks of wild-type KRAS and three high-frequency oncogenic mutants (G12C, G12D, and G12V) using TurboID proximity labeling coupled with quantitative proteomics. Bioinformatic analysis revealed mutant-specific binding partners and metabolic pathway alterations, including significant enrichment in insulin signaling, reactive oxygen species regulation, and glucose/lipid metabolism. These changes collectively drive tumor proliferation and immune evasion. Comparative analysis identified shared interactome shifts across all mutants: reduced binding to LZTR1, an adaptor for KRAS degradation, and enhanced recruitment of LAMTOR1, a regulator of mTORC1-mediated growth signaling. Our multi-dimensional profiling establishes the first comprehensive map of KRAS-mutant interactomes and links specific mutations to metabolic reprogramming. These findings provide mechanistic insights into KRAS-driven malignancy and highlight LZTR1 and LAMTOR1 as potential therapeutic targets. The study further lays a foundation for developing mutation-specific strategies to counteract KRAS oncogenic signaling.

The initiation and progression of clear cell renal cell carcinoma (ccRCC) are closely linked to significant metabolic alterations. Specifically, lipid metabolism alterations and their association with the high invasiveness in ccRCC require further investigation. After conducting RNA-sequencing (RNA-seq), we discovered that Hydroxyacyl-CoA Dehydrogenase Trifunctional Multienzyme Complex Subunit Beta (HADHB) was significantly downregulated in the highly invasive ccRCC cell line. It was found that the expression of HADHB in ccRCC tumor tissues was lower than that in paracancer tissues, which is associated with poor patient prognosis. Subsequently, we confirmed that highly invasive ccRCC exhibited an increased lipid accumulation due to the suppression of mitochondrial fatty acid transport and enhanced conversion of fatty acids to triglycerides within cancer cells. Specifically, the downregulation of HADHB inhibited mitochondrial fatty acid β-oxidation (FAO) in cancer cells, leading to partial impairment of mitochondrial function and decreased ATP production. However, this trade-off involving the reduction of a high-yield ATP production conferred an advantage by reducing reactive oxygen species (ROS) generation within cancer cells, thereby protecting them from oxidative stress and enhancing their invasive potential. Furthermore, the downregulation of HADHB promoted epithelial-mesenchymal transition (EMT) and angiogenesis in cancer cells, accelerating the progression of ccRCC and endowing ccRCC cells with metastatic capabilities.

PRCC-TFE3 rearrangement renal cell carcinoma (rRCC) is an independent subtype of rRCC caused by chromosomal translocation and rearrangement. Previous studies have revealed that nicotinamide riboside kinase 2 (NMRK2), which is transcriptionally upregulated by PRCC-TFE3 fusion protein, as a pivotal molecule in the energy metabolism remodeling of PRCC-TFE3 rRCC. However, the molecular mechanism by which NMRK2-mediated enhancement of nicotinamide adenine dinucleotide (NAD+) synthesis contributes to tumor progression in PRCC-TFE3 rRCC remains unclear. In this study, utilizing immune system-humanized mice model and in vitro cell models, we demonstrated that elevated expression of NMRK2 impaired the cytotoxic functions of CD8+T cells, leading to the emergence of immune-ignorant phenotypes in PRCC-TFE3 rRCC. Furthermore, it was shown that the increased NAD+ metabolism driven by NMRK2 enhanced the stability of CD38 protein through SIRT1-mediated deacetylation, which underlines impairment of CD8+T cells and the development of an immunosuppressive state in PRCC-TFE3 rRCC. Our findings not only elucidated a mechanism underlying immunological ignorance in PRCC-TFE3 rRCC but also propose potential therapeutic targets.

BACKGROUND:Primary spontaneous pneumothorax is a rare disease commonly found in young adults, with unknown aetiology. We aimed to investigate the susceptibility genes and the downstream signalling involved in the development of primary spontaneous pneumothorax. METHODS:We conducted the first large-scale genome-wide association study (GWAS) composed of 2223 patients and 3838 controls. The functional role of the novel susceptibility loci was investigated by both in vivo and in vitro assays. Gene expression profiling in lung epithelial cell lines was performed, and conditional gene knockout mice were generated. RESULTS:We identified four novel susceptibility loci at 14q32.2 near C14orf177, at 15q26.3 near CHSY1, at 16q23.1 near CFDP1 and at 22q13.1 near CBX7. The fine-mapping of 22q13.1 revealed a functional variant which regulated CBX7 expression by disrupting the binding activity of transcription factor CREB1. Conditional knockout of Cbx7 in mouse lung epithelial cells resulted in lung cyst formation. Meanwhile, downregulation of the CBX7 elevated the expression of MMP9 and MMP16, which are part of extracellular matrix regulators and may lead to lung injury. CONCLUSIONS:Our GWAS discovered four novel susceptibility loci of primary spontaneous pneumothorax and presented a mechanistic basis for the genetic association with primary spontaneous pneumothorax. The novel susceptibility gene CBX7 and downstream MMP signalling give a new clue to the pathogenesis of primary spontaneous pneumothorax.

Pancreatic cancer (PC) is associated with dismal clinical outcomes, largely due to the high prevalence of liver metastasis (LM) at diagnosis or post-resection. Despite its clinical significance, the molecular drivers of LM in PC remain poorly characterized, and few validated biomarkers or therapeutic targets are currently available. Our study identifies 7-dehydrocholesterol reductase (DHCR7), a terminal enzyme in cholesterol biosynthesis, as significantly upregulated in PC tissues and closely correlated with LM progression. In vitro experiments demonstrated that DHCR7 enhances the proliferation, invasion, and migration ability in PC cells, and in vivo experiments demonstrated that DHCR7 promotes LM of PC. The mechanism of DHCR7 promoting LM may be mediated by elevating cholesterol synthesis of PC cells and then activating the PI3K-Akt signaling pathway. Taken together, our findings uncover a novel molecular mechanism underlying LM in PC and highlight DHCR7 as a possible predictive biomarker or interventional target.

Background: Diabetic peripheral neuropathy (DPN) is considered one of the most common chronic complications of diabetes. Impairment of mitochondrial function is regarded as one of the causes. Iron–sulfur clusters are essential cofactors for numerous iron–sulfur (Fe-S)-containing proteins/enzymes, including mitochondrial electron transport chain complex I, II, and III and aconitase. Methods: To determine the impact of hyperglycemia on peripheral nerves, we used Schwann-like RSC96 cells and classical db/db mice to detect the expression of Fe-S-related proteins, mitochondrially enzymatic activities, and iron metabolism. Subsequently, we treated high-glucose-induced RSC96 cells and db/db mice with pioglitazone (PGZ), respectively, to evaluate the effects on Fe-S cluster biogenesis, mitochondrial function, and animal behavior. Results: We found that the core components of Fe-S biogenesis machinery, such as frataxin (Fxn) and scaffold protein IscU, significantly decreased in high-glucose-induced RSC96 cells and db/db mice, accompanied by compromised mitochondrial Fe-S-containing enzymatic activities, such as complex I and II and aconitase. Consequently, oxidative stress and inflammation increased. PGZ not only has antidiabetic effects but also increases the expression of Fxn and IscU to enhance mitochondrial function in RSC96 cells and db/db mice. Meanwhile, PGZ significantly alleviated sciatic nerve injury and improved peripheral neuronal behavior, accompanied by suppressed oxidative stress and inflammation in the sciatic nerve of the db/db mice. Conclusions: Iron–sulfur cluster deficiency may contribute to hyperglycemia-mediated DPN.

6:2 Fluorotelomer alcohol (6:2 FTOH) is a raw material used in the manufacture of short-chain poly- and perfluoroalkyl substances. Our previous study revealed that gestational exposure to 6:2 FTOH can impair blood‒brain barrier (BBB) function in offspring, accompanied by anxiety-like behavior and learning memory deficits. The aim of this study was to further investigate the specific mechanism by which maternal exposure to 6:2 FTOH resulted in impaired BBB function in offspring mice. Pregnant mice were orally administered different doses of 6:2 FTOH (0, 5, 25, and 125 mg/kg/day) from gestation day 8.5 until delivery. These results confirmed that maternal 6:2 FTOH exposure impaired BBB function and disrupted the brain immune microenvironment. Subsequent investigations revealed that endothelial-to-mesenchymal transition (EndMT) in the cerebral microvascular endothelium of offspring may be the mechanism mediating functional disruption of the BBB. Mechanistic studies revealed that exposure to 6:2 FTOH upregulated ETS proto-oncogene 1 (ETS1) expression via the tumor necrosis factor-α/extracellular signal-regulated kinase 1/2 signaling pathway, which mediated disturbances in energy metabolism, leading to impaired actin dynamics and subsequently triggering the EndMT phenotype. This is the first finding indicating that gestational 6:2 FTOH exposure caused functional impairment of the BBB through ETS1-mediated EndMT in cerebral microvascular endothelial cells, potentially providing novel insight into the environmental origins of neurodevelopmental disorders.

Studies have revealed neurotoxicity, hepatotoxicity, and developmental and reproductive toxicity in mice exposed to aluminum. However, relatively few studies have been conducted to clarify the mechanism underlying the impact of embryonic exposure to aluminum on the development of the male reproductive system in offspring. Pregnant mice were administered aluminum chloride (AlCl3) by gavage from day 12.5 of gestation until birth. Our findings demonstrated that embryonic exposure to AlCl3 disrupted testicular development and spermatogenesis by impairing testicular architecture, reducing sperm count, and upregulating the expression of tight junction (TJ) protein between Sertoli cells (SCs). Further in vitro studies revealed that treatment with AlCl3 stabilized TJ proteins Occludin and ZO-1 expression by inhibiting ERK signaling pathway activation, thereby upregulating Slc25a5 expression which induced ATP production leading to disruption of cytoskeletal protein homeostasis. Therefore, the study provided a new mechanistic insight into how AlCl3 exposure interfered with testicular development and spermatogenesis while suggesting that Slc25a5 might be a target affected by AlCl3 influencing cell metabolism.

Frataxin (FXN) is required for iron-sulfur cluster biogenesis, and its loss causes the early-onset neurodegenerative disease Friedreich ataxia (FRDA). Loss of FXN is a susceptibility factor in the development of diabetes, a common metabolic complication after myocardial hypertrophy in patients with FRDA. The underlying mechanism of FXN deficient-induced hyperglycemia in FRDA is, however, poorly understood. In this study, we confirmed that the FXN deficiency mouse model YG8R develops insulin resistance in elder individuals by disturbing lipid metabolic homeostasis in adipose tissues. Evaluation of lipolysis, lipogenesis, and fatty acid β-oxidation showed that lipolysis is most severely affected in white adipose tissues. Consistently, FXN deficiency significantly decreased expression of lipolytic genes encoding adipose triglyceride lipase (Atgl) and hormone-sensitive lipase (Hsl) resulting in adipocyte enlargement and inflammation. Lipolysis induction by fasting or cold exposure remarkably upregulated FXN expression, though FXN deficiency lessened the competency of lipolysis compared with the control or wild type mice. Moreover, we found that the impairment of lipolysis was present at a young age, a few months earlier than hyperglycemia and insulin resistance. Forskolin, an activator of lipolysis, or pioglitazone, an agonist of PPARγ, improved insulin sensitivity in FXN-deficient adipocytes or mice. We uncovered the interplay between FXN expression and lipolysis and found that impairment of lipolysis, particularly the white adipocytes, is an early event, likely, as a primary cause for insulin resistance in FRDA patients at later age.

Colorectal cancer and Crohn's disease patients develop pyogenic liver abscesses due to failures of immune cells to fight off bacterial infections. Here, we show that mice lacking iron regulatory protein 2 (Irp2), globally (Irp2-/-) or myeloid cell lineage (Lysozyme 2 promoter-driven, LysM)-specifically (Irp2ΔLysM), are highly susceptible to liver abscesses when the intestinal tissue was injured with dextran sodium sulfate treatment. Further studies demonstrated that Irp2 is required for lysosomal acidification and biogenesis, both of which are crucial for bacterial clearance. In Irp2-deficient liver tissue or macrophages, the nuclear location of transcription factor EB (Tfeb) was remarkably reduced, leading to the downregulation of Tfeb target genes that encode critical components for lysosomal biogenesis. Tfeb mislocalization was reversed by hypoxia-inducible factor 2 inhibitor PT2385 and, independently, through inhibition of lactic acid production. These experimental findings were confirmed clinically in patients with Crohn's disease and through bioinformatic searches in databases from Crohn's disease or ulcerative colitis biopsies showing loss of IRP2 and transcription factor EB (TFEB)-dependent lysosomal gene expression. Overall, our study highlights a mechanism whereby Irp2 supports nuclear translocation of Tfeb and lysosomal function, preserving macrophage antimicrobial activity and protecting the liver against invading bacteria during intestinal inflammation.

Primary spontaneous pneumothorax (PSP) or pulmonary cyst is one of the manifestations of Birt-Hogg-Dubé syndrome, which is caused by pathogenic variants in FLCN gene. Genetic testing in patients with PSP identifies a certain number of missense or intronic variants. These variants are usually considered as variants of uncertain significance, whose functional interpretations pose a challenge in clinical genetics. To improve recognition of pathogenic splice-altering variants in FLCN gene, computational tools are used to prioritize potential splice-altering variants and then a hybrid minigene assay is performed to verify the RNA splicing pattern. Herein, variants in FLCN exon 11 and its flanking sequence are focused. Eight variants detected in 11 patients with PSP are evaluated, and six variants are prioritized by in silico tools as potential splice-altering variants of uncertain significance. Four variants (c.1177-5_1177-3delCTC, c.1292_1300+4del, c.1300+4C>T, and c.1300+5G>A) are demonstrated by minigene assay to alter RNA splicing of FLCN, and the last three of them are novel. RT-PCR of patient-derived RNA gives consistent results. Genotype-phenotype correlation analysis in patients with PSP with these variants demonstrates good concordance. Our results underline the importance of RNA analysis, which could provide molecular evidence for pathogenicity of a variant, and provide essential information for the clinical interpretation of variants. Combining the clinical information, a definitive diagnosis could be made.

Cardiovascular diseases (CVDs) are among the most morbid and deadly types of diseases worldwide, while the existing therapeutic approaches all have their limitations. Mouse heart undergoes a very complex postnatal developmental process, including the 1-week window in which cardiomyocytes (CMs) maintain relatively high cell activity. The underlying mechanism provides an attractive direction for CVDs treatment. Herein, we collected ventricular tissues from mice of different ages from E18.5D to P8W and performed iTRAQ-based quantitative proteomics to characterize the atlas of cardiac development. A total of 3422 proteins were quantified at all selected time points, revealing critical proteomic changes related to cardiac developmental events such as the metabolic transition from glycolysis to beta-oxidation. A cluster of significantly dysregulated proteins containing proteins that have already been reported to be associated with cardiac regeneration (Erbb2, Agrin, and Hmgb) was identified. Meanwhile, the peroxisome proliferator-activated receptor (PPAR) signaling pathway (Cpt1α, Hmgcs2, Plin2, and Fabp4) was also found specifically enriched. We further revealed that bezafibrate, a pan-activator of PPAR signaling pathway markedly enhanced H9C2 cardiomyocyte activity via enhancing Cpt1α expression. This work provides new hint that activation of PPAR signaling pathway could potentially be a therapeutic strategy for the treatment of CVDs.

Severe fever with thrombocytopenia syndrome (SFTS) is an acute infectious disease caused by novel bunyavirus (SFTSV), with a mortality rate of 6.3% ~ 30%. To date, there is no specific treatment for SFTS. Previously, we demonstrated that SFTSV surface glycoprotein (Glycoprotein N, Gn) was a potential target for the development of SFTS vaccine or therapeutic antibodies, and anti-Gn neutralizing antibodies played a protective role in SFTS infection. Compared with traditional antibodies, nanobodies from camelids have various advantages, including small molecular weight, high affinity, low immunogenicity, convenient production by gene engineering, etc. In this study, we combined next-generation sequencing (NGS) with proteomics technology based on affinity purification-mass spectrometry (AP-MS) and bioinformatics analysis to high-throughput screen monoclonal anti-Gn nanobodies from camel immunized with Gn protein. We identified 19 anti-Gn monoclonal nanobody sequences, of which six sequences were selected for recombinant protein expression and purification. Among these six anti-Gn nanobodies, nanobody 57,493 was validated to be highly specific for Gn. The innovative high-throughput technical route developed in this study could also be expanded to the production of nanobodies specific for other viruses like SARS-CoV-2.

Background and Purpose Cancer cachexia is a common cause of death among cancer patients with no currently effective treatment available. In animal models, aberrant activation of STAT3 in skeletal muscle contributes to muscle wasting. However, clinically the factors regulating STAT3 activation and the molecular mechanisms involved remain incompletely understood. Experimental Approach The expression of HSP90 and the activation of STAT3 were detected in muscle from the patients with cancer cachexia or the tumour-bearing cachectic mice. HSP90 inhibitors, including 17DMAG (alvespimycin) and PU-H71, were administered to cachexic mice and cachexia parameters, weight loss, food intake, survival rate, body composition, serum metabolites, muscle wasting pathology and catabolic activation were analysed. The co-culture of C2C12 myotube cells with C26 conditioned media was performed to investigate the pathological mechanism involved in catabolic muscle wasting. The roles of HSP90, STAT3 and FOXO1 in myotube atrophy were explored via overexpression or knockdown. Results An enhanced interaction between activated STAT3 and HSP90 in the skeletal muscle of cancer cachexia patients, is a crucial for the development of cachectic muscle wasting. HSP90 inhibitors 17DMAG and PU-H71 alleviated the muscle wasting in C26 and models or the myotube atrophy of C2C12 cells induced by C26 conditional medium. Prolonged STAT3 activation transactivated FOXO1 by binding directly to its promoter and triggered the muscle wasting in a FOXO1-dependent manner in muscle cells. Conclusion and Implications The HSP90/STAT3/FOXO1 axis plays a critical role in cachectic muscle wasting, which might be a potential therapeutic target for the treatment of cancer cachexia.

Pulmonary fibrosis is a common cause of pulmonary hypertension and its development is associated with aberrant HDAC (histone deacetylase) activities and altered fibrogenic gene expressions; however, whether the epigenetic alterations causally affect pulmonary fibrosis remains poorly understood. Here, we report that HDAC3 aberration and the resultant inhibition of Nrf2 (nuclear factor erythroid-derived 2-related factor-2), a master transcription factor of antioxidative stress, contribute significantly to pulmonary fibrogenesis. HDAC3 is preferentially upregulated with concomitant Nrf2 suppression in fibrotic lungs of both idiopathic pulmonary fibrosis patients and bleomycin-treated mice. Genetic knockout of HDAC3 or Nrf2 inversely resisted or exacerbated the fibrotic pathologies, respectively, suggesting that they are crucial regulators of pulmonary fibrosis with opposite functions. Intriguingly, a HDAC3-selective inhibitor RGFP966 effectively reduced the Nrf2 suppression and normalized the fibrosis and adverse expressions of major fibrogenic proteins, Nrf2 downstream antioxidant enzymes and inflammatory cytokines. Nrf2 promoter contains a putative binding motif for FOXM1 (Forkhead box M1), a profibrotic transcriptional factor. HDAC3 and FOXM1 inducibly bound to Nrf2 promoter locus containing the motif in lung tissues of bleomycin mice, accompanied by reduced local histone3 acetylation, which were relieved by RGFP966. In cultured lung cells, bleomycin induction of Nrf2 suppression was partially attenuated by a FOXM1 inhibitor or when the FOXM1 motif was mutated; while in Nrf2 knockout mice, the antifibrotic effects of RGFP966 were largely reduced. Thus, HDAC3 aberration and its suppression of Nrf2 plays important roles in pulmonary fibrogenesis and strategies targeting HDAC3/Nrf2 axis by HDAC3 inhibition might potentially benefit patients with idiopathic pulmonary fibrosis and the related pulmonary fibrotic disorders.

A novel, simple and stability indicating reverse-phase high performance liquid chromatographic method with UV detection at 220 nm (RP-HPLC-UV) was established to realize the simultaneous analysis of carbetocin and ten related impurities. This paper performed the most comprehensive impurity profiling of carbetocin, including the synthesis-related impurities, the isomers of carbetocin and the degradants formed from the forced degradation research, the structures of which were tentatively identified by a two-dimensional liquid chromatography-mass spectrometry technology. The novelty of this RP-HPLC-UV method was demonstrated by its satisfactory resolution and selectivity, which was achieved using an YMC-pack C18 column kept at 40 ℃, and optimal organic modifier gradient. The mobile phase A was potassium dihydrogen phosphate buffer (pH 6.5)—acetonitrile (80:20, v/v), and the mobile phase B was potassium dihydrogen phosphate buffer (pH 6.5)—acetonitrile (72:28, v/v). The forced degradation research proved the stability-indicating capacity of the method and validation study was performed according to ICH requirements. In summary, this RP-HPLC-UV method could support the simultaneous determination of related substances of carbetocin in bulk drug and in pharmaceutical formulations.

Hypoxia is one of the most important factors that limit the effect of radiotherapy, and the abundant H2O2 in tumor tissues will also aggravate hypoxia-induced radiotherapy resistance. Delivering catalase to decompose H2O2 into oxygen is an effective strategy to relieve tumor hypoxia and radiotherapy resistance. However, low stability limits catalase's in vivo application, which is one of the most common limitations for almost all proteins' internal utilization. Here, we develop catalase containing E. coli membrane vesicles (EMs) with excellent protease resistance to relieve tumor hypoxia for a long time. Even treated with 100-fold of protease, EMs showed higher catalase activity than free catalase. After being injected into tumors post 12 h, EMs maintained their hypoxia relief ability while free catalase lost its activity. Our results indicate that EMs might be an excellent catalase delivery for tumor hypoxia relief. Combined with their immune stimulation features, EMs could enhance radiotherapy and induce antitumor immune memory effectively.