Reactive oxygen species as a double-edged sword: The role of oxidative enzymes in antitumor therapy

A biomimetic nanocarrier facilitates glucose consumption and reactive oxide species accumulation in enzyme therapy for colorectal cancer

Glucose oxidase (GOx)-based enzyme therapeutics are potential alternatives for colorectal cancer (CRC) treatment via glucose consumption and accumulation of hydrogen peroxide (H2O2). Given that H2O2 can be eliminated by cytoprotective autophagy, autophagy inhibitors that can interrupt autolysosome-induced H2O2 elimination are promising combination drugs of GOx. Here, we developed a multifunctional biomimetic nanocarrier for effective co-delivery of an autophagy inhibitor-chloroquine phosphate (CQP) and GOx to exert their synergistic effect by irreversibly upregulating intracellular reactive oxygen species (ROS) levels. Poly (D, l-lactide-co-glycolide) (PLGA) nanoparticles (NPs) were used to encapsulate both GOx and CQP using a W/O/W multi-emulsion method. Calcium phosphate (CaP) was used to "fix" CQP to GOx in the internal water phase, where it served as a pH-sensitive unit to facilitate intracellular drug release. Folic acid-modified red blood cell membranes (FR) were used to camouflage the GOx/CQP/CaP encapsulated PLGA NPs (referred to as PLGA/GCC@FR). In an AOM/DSS-induced CRC mouse model, PLGA/GCC@FR exhibited improved antitumor effects, in which the number of tumor nodes were only a quarter of that in the free drug combination group. The enhanced therapeutic effects of PLGA/GCC@FR were attributed to the prolonged tumor retention which was verified by both dynamic in vivo imaging and drug biodistribution. This multifunctional biomimetic nanocarrier facilitated combined enzyme therapeutics by depleting glucose and augmenting intracellular ROS levels in tumor cells, which exerted a synergistic inhibitory effect on tumor growth. Therefore, this study proposed a novel strategy for the enhancement of combined enzyme therapeutics, which provided a promising method for effective CRC treatment.

Targeting proteasomal deubiquitinases USP14 and UCHL5 with b-AP15 reduces 5-fluorouracil resistance in colorectal cancer cells

5-Fluorouracil (5-FU) is the first-line treatment for colorectal cancer (CRC) patients, but the development of acquired resistance to 5-FU remains a big challenge. Deubiquitinases play a key role in the protein degradation pathway, which is involved in cancer development and chemotherapy resistance. In this study, we investigated the effects of targeted inhibition of the proteasomal deubiquitinases USP14 and UCHL5 on the development of CRC and resistance to 5-FU. By analyzing GEO datasets, we found that the mRNA expression levels of USP14 and UCHL5 in CRC tissues were significantly increased, and negatively correlated with the survival of CRC patients. Knockdown of both USP14 and UCHL5 led to increased 5-FU sensitivity in 5-FU-resistant CRC cell lines (RKO-R and HCT-15R), whereas overexpression of USP14 and UCHL5 in 5-FU-sensitive CRC cells decreased 5-FU sensitivity. B-AP15, a specific inhibitor of USP14 and UCHL5, (1-5 μM) dose-dependently inhibited the viability of RKO, RKO-R, HCT-15, and HCT-15R cells. Furthermore, treatment with b-AP15 reduced the malignant phenotype of CRC cells including cell proliferation and migration, and induced cell death in both 5-FU-sensitive and 5-FU-resistant CRC cells by impairing proteasome function and increasing reactive oxygen species (ROS) production. In addition, b-AP15 inhibited the activation of NF-κB pathway, suppressing cell proliferation. In 5-FU-sensitive and 5-FU-resistant CRC xenografts nude mice, administration of b-AP15 (8 mg·kg-1·d-1, intraperitoneal injection) effectively suppressed the growth of both types of tumors. These results demonstrate that USP14 and UCHL5 play an important role in the development of CRC and resistance to 5-FU. Targeting USP14 and UCHL5 with b-AP15 may represent a promising therapeutic strategy for the treatment of CRC.

The D-amino acid oxidase-carbon nanotubes: evaluation of cytotoxicity and biocompatibility of a potential anticancer nanosystem

The 'enzyme prodrug therapy' represents a promising strategy to overcome limitations of current cancer treatments by the systemic administration of prodrugs, converted by a foreign enzyme into an active anticancer compound directly in tumor sites. One example is D-amino acid oxidase (DAAO), a dimeric flavoenzyme able to catalyze the oxidative deamination of D-amino acids with production of hydrogen peroxide, a reactive oxygen species (ROS), able to favor cancer cells death. A DAAO variant containing five aminoacidic substitutions (mDAAO) was demonstrated to possess a better therapeutic efficacy under low O2 concentration than wild-type DAAO (wtDAAO). Recently, aiming to design promising nanocarriers for DAAO, multi-walled carbon nanotubes (MWCNTs) were functionalized with polyethylene glycol (PEG) to reduce their tendency to aggregation and to improve their biocompatibility. Here, wtDAAO and mDAAO were adsorbed on PEGylated MWCNTs and their activity and cytotoxicity were tested. While PEG-MWCNTs-DAAOs have shown a higher activity than pristine MWCNTs-DAAO (independently on the DAAO variant used), PEG-MWCNTs-mDAAO showed a higher cytotoxicity than PEG-MWCNTs-wtDAAO at low O2 concentration. In order to evaluate the nanocarriers' biocompatibility, PEG-MWCNTs-DAAOs were incubated in human serum and the composition of protein corona was investigated via nLC-MS/MS, aiming to characterize both soft and hard coronas. The mDAAO variant has influenced the bio-corona composition in both number of proteins and presence of opsonins and dysopsonins: notably, the soft corona of PEG-MWCNTs-mDAAO contained less proteins and was more enriched in proteins able to inhibit the immune response than PEG-MWCNTs-wtDAAO. Considering the obtained results, the PEGylated MWCNTs conjugated with the mDAAO variant seems a promising candidate for a selective antitumor oxidative therapy: under anoxic-like conditions, this novel drug delivery system showed a remarkable cytotoxic effect controlled by the substrate addition, against different tumor cell lines, and a bio-corona composition devoted to prolong its blood circulation time, thus improving the drug's biodistribution.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-023-03568-1.

D-Amino Acids and Cancer: Friends or Foes?

α-amino acids exist in two configurations, named D-(dextro) and L-(levo) enantiomers. L-amino acids are used in protein synthesis and play a central role in cell metabolism. The effects of the L-amino acid composition of foods and the dietary modifications of this composition on the efficacy of cancer therapies have been widely investigated in relation to the growth and reproduction of cancerous cells. However, less is known about the involvement of D-amino acids. In recent decades, D-amino acids have been identified as natural biomolecules that play interesting and specific roles as common components of the human diet. Here, we focus on recent investigations showing altered D-amino acid levels in specific cancer types and on the various roles proposed for these biomolecules related to cancer cell proliferation, cell protection during therapy, and as putative, innovative biomarkers. Notwithstanding recent progress, the relationship between the presence of D-amino acids, their nutritional value, and cancer cell proliferation and survival represents an underrated scientific issue. Few studies on human samples have been reported to date, suggesting a need for routine analysis of D-amino acid content and an evaluation of the enzymes involved in regulating their levels in clinical samples in the near future.

Fluorescent molecular probes for imaging and detection of oxidases and peroxidases in biological samples

Oxidases and peroxidases are two subclasses of oxidoreductases. The abnormal expression of oxidases (such as tyrosinase, cytochrome P450 oxidases, and monoamine oxidases) and peroxidases (such as glutathione peroxidase, myeloperoxidase, and eosinophil peroxidase) is relative with some diseases. Therefore, the analysis of oxidases and peroxidases is great important for disease diagnosis and treatment. Fluorescent probes present simple protocol, high sensitivity and good stability in sensing field. Molecule fluorescent probes are constructed with chemical groups that tunes their fluorescence emission in response to binding events, chemical reactions, and the surrounding environment. A fluorescent probe is an efficient tool for visualizing the activity of enzymes in living organisms on the basis of its high specificity, sensitivity, and noninvasiveness characteristics. In this review, we focus on the sensing of oxidases and peroxidases by molecule fluorescent probes, and hope to bring new insight to wide researchers about oxidases and peroxidases in biological samples.

Copper-rich multifunctional Prussian blue nanozymes for infected wound healing

The healing process of infected wounds was limited by bacterial infection, excessive reactive oxygen species (ROS) accumulation, and tissue hypoxia. In order to alleviate the above situations, herein, a copper-rich multifunctional ultra-small Prussian blue nanozymes (HPP@Cu NZs) was constructed for infected wound synergistic treatment. Firstly, hyaluronic acid was modified by branched polyethyleneimine which could form a complex with copper ions, to construct copper-rich Prussian blue nanozymes. Secondly, the HPP@Cu NZs have a uniform ultra-small nano size and excellent photothermal response performance, exhibition of multifunctional enzymatic activity and anti-inflammatory properties. Finally, the slow release of copper ions in the HPP@Cu NZs could effectively promote the formation of new blood vessels, thus giving it multifunctional properties. In vitro and in vivo experiments showed that it not only could effectively inhibit and kill bacteria under 808 nm near-infrared laser but also could remove excessive ROS, regulate oxygen levels, and anti-inflammation. More importantly, the release of copper ions could synergistically promote the healing of infected wounds as well as good biocompatibility. Overall, our studies provide a multifunctional strategy for infected wounds with synergistic treatment based on carrier construction.

Ageing of skeletal muscle extracellular matrix and mitochondria: finding a potential link

Aim: To discuss the progress of extracellular matrix (ECM) characteristics, mitochondrial homeostasis, and their potential crosstalk in the pathogenesis of sarcopenia, a geriatric syndrome characterized by a generalized and progressive reduction in muscle mass, strength, and physical performance.Methods: This review focuses on the anatomy and physiology of skeletal muscle, alterations of ECM and mitochondria during ageing, and the role of the interplay between ECM and mitochondria in the pathogenesis of sarcopenia.Results: Emerging evidence points to a clear interplay between mitochondria and ECM in various tissues and organs. Under the ageing process, the ECM undergoes changes in composition and physical properties that may mediate mitochondrial changes via the systematic metabolism, ROS, SPARC pathway, and AMPK/PGC-1α signalling, which in turn exacerbate muscle degeneration. However, the precise effects of such crosstalk on the pathobiology of ageing, particularly in skeletal muscle, have not yet been fully understood.Conclusion: The changes in skeletal muscle ECM and mitochondria are partially responsible for the worsened muscle function during the ageing process. A deeper understanding of their alterations and interactions in sarcopenic patients can help prevent sarcopenia and improve its prognoses.

In-hospital mortality and SpO2 incritical care patients with cerebral injury: data from the MIMIC‑IV Database

BACKGROUND

Evidence regarding the relationship between in-hospital mortality and SpO2 was low oxygen saturations are often thought to be harmful, new research in patients with brain damage has found that high oxygen saturation actually enhances mortality. However, there is currently no clear study to point out the appropriate range for oxygen saturation in patients with craniocerebral diseases.  METHODS: By screening all patients in the MIMIC IV database, 3823 patients with craniocerebral diseases (according to ICD-9 codes and ICD-10) were selected, and non-linear regression was used to analyze the relationship between in-hospital mortality and oxygen saturation. Covariates for all patients included age, weight, diagnosis, duration of ICU stay, duration of oxygen therapy, etc. RESULTS: In-hospital mortality in patients with TBI and SAH was kept to a minimum when oxygen saturation was in the 94-96 range. And in all patients, the relationship between oxygen saturation and in-hospital mortality was U-shaped. Subgroup analysis of the relationship between oxygen saturation and mortality in patients with metabolic encephalopathy and other encephalopathy also draws similar conclusions In-hospital mortality and oxygen saturation were all U-shaped in patients with subarachnoid hemorrhage, metabolic and toxic encephalopathy, cerebral infarction, and other encephalopathy, but the nonlinear regression was statistically significant only in patients with cerebral infarction (p for nonlinearity = 0.002).

CONCLUSION

Focusing too much on the lower limit of oxygen saturation and ignoring too high oxygen saturation can also lead to increase in-hospital mortality. For patients with TBI and SAH, maintaining oxygen saturation at 94-96% will minimize the in-hospital mortality of patients.

Roles of Mitochondria in Oral Squamous Cell Carcinoma Therapy: Friend or Foe?

Oral squamous cell carcinoma (OSCC) therapy is unsatisfactory, and the prevalence of the disease is increasing. The role of mitochondria in OSCC therapy has recently attracted increasing attention, however, many mechanisms remain unclear. Therefore, we elaborate upon relative studies in this review to achieve a better therapeutic effect of OSCC treatment in the future. Interestingly, we found that mitochondria not only contribute to OSCC therapy but also promote resistance, and targeting the mitochondria of OSCC via nanoparticles is a promising way to treat OSCC.

Impact of Exercise and Aging on Mitochondrial Homeostasis in Skeletal Muscle: Roles of ROS and Epigenetics

Aging causes degenerative changes such as epigenetic changes and mitochondrial dysfunction in skeletal muscle. Exercise can upregulate muscle mitochondrial homeostasis and enhance antioxidant capacity and represents an effective treatment to prevent muscle aging. Epigenetic changes such as DNA methylation, histone posttranslational modifications, and microRNA expression are involved in the regulation of exercise-induced adaptive changes in muscle mitochondria. Reactive oxygen species (ROS) play an important role in signaling molecules in exercise-induced muscle mitochondrial health benefits, and strong evidence emphasizes that exercise-induced ROS can regulate gene expression via epigenetic mechanisms. The majority of mitochondrial proteins are imported into mitochondria from the cytosol, so mitochondrial homeostasis is regulated by nuclear epigenetic mechanisms. Exercise can reverse aging-induced changes in myokine expression by modulating epigenetic mechanisms. In this review, we provide an overview of the role of exercise-generated ROS in the regulation of mitochondrial homeostasis mediated by epigenetic mechanisms. In addition, the potential epigenetic mechanisms involved in exercise-induced myokine expression are reviewed.

Hypoglycemic and Antioxidant Properties of Extracts and Fractions from Polygoni Avicularis Herba

Our research focused on the hypoglycemic capability and the possible mechanisms of extract and fractions from Polygoni Avicularis Herba (PAH) based on α-glucosidase, α-amylase inhibition assays, glucose uptake experiment, HPLC-MS analysis, and molecular docking experiment. In addition, DPPH, ABTS, and FRAP assays were used for determining the antioxidant capability. The results of total flavonoids and phenolics contents showed that ethyl acetate fraction (EAF) possessed the highest flavonoids and phenolics with values of 159.7 ± 2.5 mg rutin equivalents/g and 107.6 ± 2.0 mg galic acid equivalents/g, respectively. The results of in vitro hypoglycemic activity showed that all samples had effective α-glucosidase inhibition capacities, and EAF possessed the best inhibitory effect with IC50 value of 1.58 ± 0.24 μg/mL. In addition, n-butanol fraction (NBF) significantly promoted the glucose uptake rate of 3T3-L1 adipocytes. HPLC-MS analysis and molecular docking results proved the interactions between candidates and α-glucosidase. The results of antioxidation capacities showed that EAF possessed the best antioxidation abilities with DPPH, ABTS, and FRAP. In summary, the hypoglycemic activity of PAH might be related to the inhibition of α-glucosidase (EAF > PEF > NBF) and the promotion of glucose uptake in 3T3-L1 adipocytes (NBF). Simultaneously, the antioxidation capacity of PAH might be related to the abundant contents of flavonoids and other phenolics (EAF > PEF > NBF).

Unveiling the Bio-corona Fingerprinting of Potential Anticancer Carbon Nanotubes Coupled with D-Amino Acid Oxidase

The oxidation therapy, based on the controlled production of Reactive Oxygen Species directly into the tumor site, was introduced as alternative antitumor approach. For this purpose, d-amino acid oxidase (DAAO) from the yeast Rhodotorula gracilis, an enzyme able to efficiently catalyze the production of hydrogen peroxide from d-amino acids, was adsorbed onto multi-walled carbon nanotubes (MWCNTs), previously functionalized with polylactic-co-glycolic acid (PLGA) or polyethylene glycol (PEG) at different degrees to reduce their toxicity, to be targeted directly into the tumor. In vitro activity and cytotoxicity assays demonstrated that DAAO-functionalized nanotubes (f-MWCNTs) produced H2O2 and induced toxic effects to selected tumor cell lines. After incubation in human plasma, the protein corona was investigated by SDS-PAGE and mass spectrometry analysis. The enzyme nanocarriers generally seemed to favor their biocompatibility, promoting the interaction with dysopsonins. Despite this, PLGA or high degree of PEGylation promoted the adsorption of immunoglobulins with a possible activation of immune response and this effect was probably due to PLGA hydrophobicity and dimensions and to the production of specific antibodies against PEG. In conclusion, the PEGylated MWCNTs at low degree seemed the most biocompatible nanocarrier for adsorbed DAAO, preserving its anticancer activity and forming a bio-corona able to reduce both defensive responses and blood clearance.

DPP4 Regulates DHCR24-Mediated Cholesterol Biosynthesis to Promote Methotrexate Resistance in Gestational Trophoblastic Neoplastic Cells

Metabolic reprogramming could promote cellular adaptation in response to chemotherapeutic drugs in cancer cells. Herein, we aimed to characterize the metabolomic profiles regulated by Dipeptidyl Peptidase 4 (DPP4) in methotrexate (MTX)-resistant gestational trophoblastic neoplastic (GTN) cells. A total of eighty metabolites were found to be commonly altered in DPP4-depleted JAR/MTX and JEG3/MTX cells. Cholesterol biosynthesis-related metabolites were markedly impacted by DPP4 knockdown in MTX-resistant sublines. Manipulation of DPP4 expression remarkably affected the level of cellular cholesterol in GTN cells. Our analysis also identified 24-Dehydrocholesterol Reductase (DHCR24) as a potential downstream effector of DPP4. Manipulation of DHCR24 expression affected cellular cholesterol level, reactive oxygen species (ROS) accumulation, and chemosensitivity to MTX in GTN cell models. In addition, over-expression of DHCR24 could markedly restore cellular cholesterol level and rescue cell survival in DPP4-depleted MTX-resistant GTN cells. Highly correlated expression of DPP4 and DHCR24 was observed in clinical GTN specimens. Further, DPP4 inhibitor sitagliptin effectively inhibited cholesterol biosynthesis, reduced DHCR24 expression and enhanced MTX-induced cytotoxicity in vitro and in vivo. In conclusion, our findings suggested that DPP4 might regulate DHCR24-mediated cholesterol biosynthesis to promote methotrexate resistance in GTN cells. Targeting DPP4/DHCR24 signaling might help to sensitize MTX-resistant GTN to MTX treatment.