Acetyl-CoA synthetase 2 contributes to a better prognosis for liver cancer by switching acetate-glucose metabolism.

Acetyl-CoA synthetase 2 (ACSS2)-dependent acetate usage has generally been associated with tumorigenesis and increased malignancy in cancers under nutrient-depleted conditions. However, the nutrient usage and metabolic characteristics of the liver differ from those of other organs; therefore, the mechanism of ACSS2-mediated acetate metabolism may also differ in liver cancer. To elucidate the underlying mechanisms of ACSS2 in liver cancer and acetate metabolism, the relationships between patient acetate uptake and metabolic characteristics and between ACSS2 and tumor malignancies were comprehensively studied in vitro, in vivo and in humans. Clinically, we initially found that ACSS2 expression was decreased in liver cancer patients. Moreover, PET-CT imaging confirmed that lower-grade cancer cells take up more 11C-acetate but less 18F-fluorodeoxyglucose (18F-FDG); however, this trend was reversed in higher-grade cancer. Among liver cancer cells, those with high ACSS2 expression avidly absorbed acetate even in a glucose-sufficient environment, whereas those with low ACSS2 expression did not, thereby showing correlations with their respective ACSS2 expression. Metabolomic isotope tracing in vitro and in vivo revealed greater acetate incorporation, greater lipid anabolic metabolism, and less malignancy in high-ACSS2 tumors. Notably, ACSS2 downregulation in liver cancer cells was associated with increased tumor occurrence in vivo. In human patient cohorts, patients in the low-ACSS2 subgroup exhibited reduced anabolism, increased glycolysis/hypoxia, and poorer prognosis. We demonstrated that acetate uptake by ACSS2 in liver cancer is independent of glucose depletion and contributes to lipid anabolic metabolism and reduced malignancy, thereby leading to a better prognosis for liver cancer patients.

Rhizobial oxidized 3-hydroxylbutanoyl glycan-based gelatin hydrogels with enhanced physiochemical properties for pH-responsive drug delivery.

Rhizobial exopolysaccharide (EPS) is an acidic polysaccharide involved in nitrogen fixation-related signal transduction in the rhizosphere, serving as a structural support for biofilms, and protecting against various external environmental stresses. Rhizobial EPS as a hydrogel biomaterial was used for a pH-responsive drug delivery system combing with gelatins. Pure gelatin (GA) hydrogels have limited practical applications due to their poor mechanical strength and poor thermal stability. We developed new GA hydrogels using oxidized 3-hydroxylbutanoyl glycan (OHbG) as a polymer cross-linking agent to overcome these limitations. OHbG was synthesized from sodium periodate oxidation of 3-hydroxylbutanoyl glycan directly isolated from Rhizobium leguminosarum bv. viciae VF39. The newly fabricated OHbG/GA hydrogels exhibited 21-fold higher compressive stress and 4.7-fold higher storage modulus (G') than GA at the same strain. This result suggested that OHbG provided mechanical improvement. In addition, these OHbG/GA hydrogels showed effective pH-controlled drug release for 5-fluorouracil, self-healable, and self-antioxidant capacity by uronic acids of OHbG. Cell viability tests using HEK-293 cells in vitro also showed that the OHbG/GA hydrogels were non-toxic. This suggests that the new OHbG/GA hydrogels can be used as a potentially novel biomaterial for drug delivery based on its self-healing ability, antioxidant capacity, and pH-responsive drug delivery.

Lactate as a major epigenetic carbon source for histone acetylation via nuclear LDH metabolism.

Histone acetylation involves the transfer of two-carbon units to the nucleus that are embedded in low-concentration metabolites. We found that lactate, a high-concentration metabolic byproduct, can be a major carbon source for histone acetylation through oxidation-dependent metabolism. Both in cells and in purified nuclei, 13C3-lactate carbons are incorporated into histone H4 (maximum incorporation: ~60%). In the purified nucleus, this process depends on nucleus-localized lactate dehydrogenase (LDHA), knockout (KO) of which abrogates incorporation. Heterologous expression of nucleus-localized LDHA reverses the KO effect. Lactate itself increases histone acetylation, whereas inhibition of LDHA reduces acetylation. In vitro and in vivo settings exhibit different lactate incorporation patterns, suggesting an influence on the microenvironment. Higher nuclear LDHA localization is observed in pancreatic cancer than in normal tissues, showing disease relevance. Overall, lactate and nuclear LDHA can be major structural and regulatory players in the metabolism-epigenetics axis controlled by the cell's own status or the environmental status.

A pH-sensitive drug delivery using biodegradable succinoglycan/chitosan hydrogels with synergistic antibacterial activity.

Since succinoglycan (SG) produced by Sinorhizobium meliloti is an anionic polysaccharide having substituents such as succinate and pyruvate groups, a polyelectrolyte composite hydrogel can be made together with chitosan (CS), a cationic polysaccharide. We fabricated polyelectrolyte SG/CS hydrogels using the semi-dissolving acidified sol-gel transfer (SD-A-SGT) method. The hydrogel showed optimized mechanical strength and thermal stability at an SG:CS weight ratio of 3:1. This optimized SG/CS hydrogel exhibited a high compressive stress of 497.67 kPa at 84.65 % strain and a high tensile strength of 9.14 kPa when stretched to 43.73 %. Additionally, this SG/CS hydrogel showed a pH-controlled drug release pattern for 5-fluorouracil (5-FU), where a change from pH 7.4 to 2.0 increased the release from 60 % to 94 %. In addition, this SG/CS hydrogel not only showed a cell viability of 97.57 %, but also showed synergistic antibacterial activity of 97.75 % and 96.76 % against S. aureus and E. coli, respectively. These results indicate the potential of this hydrogel as a biocompatible and biodegradable hydrogel material for wound healing, tissue engineering, and drug release systems.

GPX8 regulates clear cell renal cell carcinoma tumorigenesis through promoting lipogenesis by NNMT.

BACKGROUND: Clear cell renal cell carcinoma (ccRCC), with its hallmark phenotype of high cytosolic lipid content, is considered a metabolic cancer. Despite the implication of this lipid-rich phenotype in ccRCC tumorigenesis, the roles and regulators of de novo lipid synthesis (DNL) in ccRCC remain largely unexplained. METHODS: Our bioinformatic screening focused on ccRCC-lipid phenotypes identified glutathione peroxidase 8 (GPX8), as a clinically relevant upstream regulator of DNL. GPX8 genetic silencing was performed with CRISPR-Cas9 or shRNA in ccRCC cell lines to dissect its roles. Untargeted metabolomics, RNA-seq analyses, and other biochemical assays (e.g., lipid droplets staining, fatty acid uptake, cell proliferation, xenograft, etc.) were carried out to investigate the GPX8's involvement in lipid metabolism and tumorigenesis in ccRCC. The lipid metabolic function of GPX8 and its downstream were also measured by isotope-tracing-based DNL flux measurement. RESULTS: GPX8 knockout or downregulation substantially reduced lipid droplet levels (independent of lipid uptake), fatty acid de novo synthesis, triglyceride esterification in vitro, and tumor growth in vivo. The downstream regulator was identified as nicotinamide N-methyltransferase (NNMT): its knockdown phenocopied, and its expression rescued, GPX8 silencing both in vitro and in vivo. Mechanically, GPX8 regulated NNMT via IL6-STAT3 signaling, and blocking this axis suppressed ccRCC survival by activating AMPK. Notably, neither the GPX8-NNMT axis nor the DNL flux was affected by the von Hippel Lindau (VHL) status, the conventional regulator of ccRCC high lipid content. CONCLUSIONS: Taken together, our findings unravel the roles of the VHL-independent GPX8-NNMT axis in ccRCC lipid metabolism as related to the phenotypes and growth of ccRCC, which may be targeted for therapeutic purposes.

TAK-981, a SUMOylation inhibitor, suppresses AML growth immune-independently.

Acute myeloid leukemia (AML) generally has an unsatisfactory prognosis despite the recent introduction of new regimens, including targeted agents and antibodies. To find a new druggable pathway, we performed integrated bioinformatic pathway screening on large OHSU and MILE AML databases, discovered the SUMOylation pathway, and validated it independently with an external data set (totaling 2959 AML and 642 normal sample data). The clinical relevance of SUMOylation in AML was supported by its core gene expression which is correlated with patient survival, European LeukemiaNet 2017 risk classification, and AML-relevant mutations. TAK-981, a first-in-class SUMOylation inhibitor currently under clinical trials for solid tumors, showed antileukemic effects with apoptosis induction, cell-cycle arrest, and induction of differentiation marker expression in leukemic cells. It exhibited potent nanomolar activity, often stronger than that of cytarabine, which is part of the standard of care. TAK-981's utility was further demonstrated in in vivo mouse and human leukemia models as well as patient-derived primary AML cells. Our results also indicate direct and cancer cell-inherent anti-AML effects by TAK-981, different from the type 1 interferon and immune-dependent mechanism in a previous solid tumor study. Overall, we provide a proof-of-concept for SUMOylation as a new targetable pathway in AML and propose TAK-981 as a promising direct anti-AML agent. Our data should prompt studies on optimal combination strategies and transitions to clinical trials in AML.

Non-bioenergetic roles of mitochondrial GPD2 promote tumor progression.

Rationale: Despite growing evidence for mitochondria's involvement in cancer, the roles of specific metabolic components outside the respiratory complex have been little explored. We conducted metabolomic studies on mitochondrial DNA (mtDNA)-deficient (ρ0) cancer cells with lower proliferation rates to clarify the undefined roles of mitochondria in cancer growth. Methods and results: Despite extensive metabolic downregulation, ρ0 cells exhibited high glycerol-3-phosphate (G3P) level, due to low activity of mitochondrial glycerol-3-phosphate dehydrogenase (GPD2). Knockout (KO) of GPD2 resulted in cell growth suppression as well as inhibition of tumor progression in vivo. Surprisingly, this was unrelated to the conventional bioenergetic function of GPD2. Instead, multi-omics results suggested major changes in ether lipid metabolism, for which GPD2 provides dihydroxyacetone phosphate (DHAP) in ether lipid biosynthesis. GPD2 KO cells exhibited significantly lower ether lipid level, and their slower growth was rescued by supplementation of a DHAP precursor or ether lipids. Mechanistically, ether lipid metabolism was associated with Akt pathway, and the downregulation of Akt/mTORC1 pathway due to GPD2 KO was rescued by DHAP supplementation. Conclusion: Overall, the GPD2-ether lipid-Akt axis is newly described for the control of cancer growth. DHAP supply, a non-bioenergetic process, may constitute an important role of mitochondria in cancer.

Chemical Biopsy for GNMT as Noninvasive and Tumorigenesis-Relevant Diagnosis of Liver Cancer.

Early diagnosis of hepatocellular carcinoma (HCC) is difficult; the lack of convenient biomarker-based diagnostic modalities renders high-risk HCC patients burdened by life-long periodical examinations. Here, a new chemical biopsy approach was developed for noninvasive diagnosis of HCC using urine samples. Bioinformatic screening for tumor suppressors yielded glycine N-methyltransferase (GNMT) as a biomarker with clinical relevance to HCC tumorigenesis. A liquid chromatography-mass spectrometry (LC-MS)-based chemical biopsy detecting nonradioactive 13C-sarcosine from 13C-glycine was designed to noninvasively assess liver GNMT activity extrahepatically. 13C-Sarcosine showed a strong correlation with GNMT in normal and cancerous liver cells. In an autochthonous animal model developing visible cancer nodules at 17 weeks, the urinary 13C-sarcosine chemical biopsy exhibited notable changes as early as 8 weeks, showing significant correlations with liver GNMT and molecular pathological changes. Our chemical biopsy approach should facilitate early and noninvasive diagnosis of HCC, with direct relevance to tumorigenesis, which can be straightforwardly applied to other diseases.

The miR-15b-Smurf2-HSP27 axis promotes pulmonary fibrosis.

BACKGROUND: Heat shock protein 27 (HSP27) is overexpressed during pulmonary fibrosis (PF) and exacerbates PF; however, the upregulation of HSP27 during PF and the therapeutic strategy of HSP27 inhibition is not well elucidated. METHODS: We have developed a mouse model simulating clinical stereotactic body radiotherapy (SBRT) with focal irradiation and validated the induction of RIPF. HSP25 (murine form of HSP27) transgenic (TG) and LLC1-derived orthotropic lung tumor models were also used. Lung tissues of patients with RIPF and idiopathic pulmonary fibrosis, and lung tissues from various fibrotic mouse models, as well as appropriated cell line systems were used. Public available gene expression datasets were used for therapeutic response rate analysis. A synthetic small molecule HSP27 inhibitor, J2 was also used. RESULTS: HSP27 expression with its phosphorylated form (pHSP27) increased during PF. Decreased mRNA expression of SMAD-specific E3 ubiquitin-protein ligase 2 (Smurf2), which is involved in ubiquitin degradation of HSP27, was responsible for the increased expression of pHSP27. In addition, increased expression of miRNA15b was identified with decreased expression of Smurf2 mRNA in PF models. Inverse correlation between pHSP27 and Smurf2 was observed in the lung tissues of PF animals, an irradiated orthotropic lung cancer models, and PF tissues from patients. Moreover, a HSP27 inhibitor cross-linked with HSP27 protein to ameliorate PF, which was more effective when targeting the epithelial to mesenchymal transition (EMT) stage of PF. CONCLUSIONS: Our findings identify upregulation mechanisms of HSP27 during PF and provide a therapeutic strategy for HSP27 inhibition for overcoming PF.

Efferocytosis and enhanced FPR2 expression following apoptotic cell instillation attenuate radiation-induced lung inflammation and fibrosis.

Lung inflammation and fibrosis are common side effects of radiotherapy that can lead to serious reduction in the quality of life of patients. However, no effective treatment is available, and the mechanisms underlying its pathophysiology are poorly understood. Irradiation increases formyl peptide receptor 2 (FPR2) expression in lung tissue, and FPR2 agonists are known to promote the uptake of apoptosis cells, referred to as efferocytosis that is a hallmark of the resolution of inflammation. Herein, in a mouse model of radiation-induced lung injury (RILI), efferocytosis was induced by injecting apoptotic cells into the lung through the trachea, and its correlation with FPR expression and the effect of efferocytosis and FPR expression on RILI were assessed. Interestingly, when apoptotic cells were injected into the lung, the radiation-induced increase in FPR2 expression was further amplified. In the mouse model of RILI, apoptotic cell instillation reduced the volume of the damaged lung and prevented the decrease in lung function. Additionally, the expression of inflammatory cytokines, fibrosis-related markers, and oxidative stress-related markers was reduced by apoptotic cell instillation. Co-administration of apoptotic Jurkat cells and WRW4, the FPR2 antagonist, reversed these effects. These findings suggest that efferocytosis induced by apoptotic cell instillation and enhanced FPR2 expression attenuate RILI, thereby alleviating lung inflammation and fibrosis.

Bipolar Resistive Switching Behavior of PVP-GQD/HfOx/ITO/Graphene Hybrid Flexible Resistive Random Access Memory.

We have investigated highly flexible memristive devices using reduced graphene oxide (RGO) nanosheet nanocomposites with an embedded GQD Layer. Resistive switching behavior of poly (4-vinylphenol):graphene quantum dot (PVP:GQD) composite and HfOx hybrid bilayer was explored for developing flexible resistive random access memory (RRAM) devices. A composite active layer was designed based on graphene quantum dots, which is a low-dimensional structure, and a heterogeneous active layer of graphene quantum dots was applied to the interfacial defect structure to overcome the limitations. Increasing to 0.3-0.6 wt % PVP-GQD, Vf changed from 2.27-2.74 V. When negative deflection is applied to the lower electrode, electrons travel through the HfOx/ITO interface. In addition, as the PVP-GQD concentration increased, the depth of the interfacial defect decreased, and confirmed the repetition of appropriate electrical properties through Al and HfOx/ITO. The low interfacial defects help electrophoresis of Al+ ions to the PVP GQD layer and the HfOx thin film. A local electric field increase occurred, resulting in the breakage of the conductive filament in the defect.

Cystic Primary Hepatic Neuroendocrine Tumor.

Neuroendocrine tumors (NETs) can arise throughout the body. Most NETs in the liver are metastatic tumors; primary hepatic NET (PHNET) is extremely rare. A diagnosis of PHNET is very difficult. No single modality can diagnose PHNET by itself, and it often resembles other hypervascular masses of the liver. This paper reports the case of a 51-year old female with a large hepatic mass. Unlike most of PHNETs reported previously, it was composed of a solid mass with mainly multiple cystic lesions, which led to an erroneous diagnosis of hepatic mucinous cystadenoma or cystadenocarcinoma. PHNET with cystic lesions is extremely rare, and the features are not well studied. This case may help physicians suspect PHNET in a differential diagnosis of an atypical hepatic mass.

PM014 attenuates radiation-induced pulmonary fibrosis via regulating NF-kB and TGF-b1/NOX4 pathways.

Radiation therapy is the mainstay in the treatment of lung cancer, and lung fibrosis is a radiotherapy-related major side effect that can seriously reduce patient's quality of life. Nevertheless, effective strategies for protecting against radiation therapy-induced fibrosis have not been developed. Hence, we investigated the radioprotective effects and the underlying mechanism of the standardized herbal extract PM014 on radiation-induced lung fibrosis. Ablative radiation dose of 75 Gy was focally delivered to the left lung of mice. We evaluated the effects of PM014 on radiation-induced lung fibrosis in vivo and in an in vitro model. Lung volume and functional changes were evaluated using the micro-CT and flexiVent system. Fibrosis-related molecules were evaluated by immunohistochemistry, western blot, and real-time PCR. A orthotopic lung tumour mouse model was established using LLC1 cells. Irradiated mice treated with PM014 showed a significant improvement in collagen deposition, normal lung volume, and functional lung parameters, and these therapeutic effects were better than those of amifostine. PM104 attenuated radiation-induced increases in NF-κB activity and inhibited radiation-induced p65 translocation, ROS production, DNA damage, and epithelial-mesenchymal transition. PM104 effectively alleviated fibrosis in an irradiated orthotopic mouse lung tumour model while not attenuating the efficacy of the radiation therapy by reduction of the tumour. Standardized herbal extract PM014 may be a potential therapeutic agent that is able to increase the efficacy of radiotherapy by alleviating radiation-induced lung fibrosis.

High-Performance Core/Shell of ZnO/TiO2 Nanowire with AgCl-Doped CdSe Quantum Dots Arrays as Electron Transport Layer for Perovskite Solar Cells.

Most previous studies of perovskite core/shell structures have been based on ZnO/TiO2 nanowires (NWs), which are not suitable for high photoelectric conversion efficiency. Here, core/shell ZnO/TiO2 NWs with AgCl-doped CdSe quantum dots were fabricated as an electron transport layer (ETL) for perovskite solar cells, based on ZnO/TiO2 arrays. We designed CdSe with AgCl dopants that were synthesized by a colloidal process. An improvement of the recombination barrier (Rct1), due to shell supplementation with AgCl-doped CdSe quantum dots, improved the open circuit voltage, the fill factor, and the adsorption capacity of CH3NH3PbI3 perovskite with NWs. The enhanced cell steady state was attributable to TiO2 with AgCl-doped CdSe QD supplementation. A maximum power conversion efficiency of 15.12% was attained in an atmospheric environment. The mechanism of the recombination and electron transport in the perovskite solar cells becoming the basis of ZnO/TiO2 core/shell arrays was investigated to represent the merit of ZnO/TiO2 core/shell arrays as an electron transport layer in effective devices. These results showed an uncomplicated approach for restraining non-radiative recombination loss in hetero-structure core/shell arrays to significantly improve perovskite solar cell performance and increase the effectiveness of photovoltaics.

LXA4-FPR2 signaling regulates radiation-induced pulmonary fibrosis via crosstalk with TGF-ß/Smad signaling.

Radiation therapy is an important modality in the treatment of lung cancer, but it can lead to radiation pneumonitis, and eventually radiation fibrosis. To date, only few available drugs can effectively manage radiation-induced pulmonary fibrosis. Lipoxins are endogenous molecules exhibit anti-inflammatory and pro-resolving effects. These molecules play a vital role in reducing excessive tissue injury and chronic inflammation; however, their effects on radiation-induced lung injury (RILI) are unknown. In this study, we investigated the effects of lipoxin A4 (LXA4) on RILI using our specialized small-animal model of RILI following focal-ablative lung irradiation (IR). LXA4 significantly inhibited immune-cell recruitment and reduced IR-induced expression of pro-inflammatory cytokines and fibrotic proteins in the lung lesion sites. In addition, micro-CT revealed that LXA4 reduced IR-induced increases in lung consolidation volume. The flexiVentTM assays showed that LXA4 significantly reversed IR-induced lung function damage. Moreover, LXA4 downregulated the activities of NF-κB and the Smad-binding element promoters. The expression of FPR2, an LXA4 receptor, increased during the development of IR-induced pulmonary fibrosis, whereas silencing of endogenous LXA4 using an antagonist (WRW4) or FPR2 siRNA resulted in impaired development of pulmonary fibrosis in response to IR. Collectively, these data suggest that LXA4 could serve as a potent therapeutic agent for alleviating RILI.

Identification of molecular signatures involved in radiation-induced lung fibrosis.

In radiotherapy, radiation (IR)-induced lung fibrosis has severe and dose-limiting side effects. To elucidate the molecular effects of IR fibrosis, we examined the fibrosis process in irradiated mouse lung tissues. High focal IR (90 Gy) was exposed to a 3-mm volume of the left lung in C57BL6 mice. In the diffused irradiation, 20 Gy dose delivered with a 7-mm collimator almost covered the entire left lung. Histological examination for lung tissues of both irradiated and neighboring regions was done for 4 weeks after irradiation. Long-term effects (12 months) of 20Gy IR were compared on a diffuse region of the left lung and non-irradiated right lung. Fibrosis was initiated as early as 2 weeks after IR in the irradiated lung region and neighboring region. Upregulation of gtse1 in both 90Gy-irradiated and neighboring regions was observed. Upregulation of fgl1 in both 20Gy diffused irradiated and non-irradiated lungs was identified. When gtse1 or flg1 was knock-downed, TGFß or IR-induced epithelial-mesenchymal transition was inhibited, accompanied with the inhibition of cellular migration, suggesting fibrosis responsible genes. Immunofluorescence analysis using mouse fibrotic lung tissues suggested that fibrotic regions showed increased expressions of Gtse1 and Fgl1, indicating novel molecular signatures of gtse1and fgl1 for IR-induced lung fibrosis. Even though their molecular mechanisms and IR doses or irradiated volumes for lung fibrosis may be different, these genes may be novel targets for understanding IR-induced lung fibrosis and in treatment strategies. KEY MESSAGES: Upregulation of gtse1 by 90Gy focal irradiation and upregulation of fgl1 by 20Gy diffused irradiation are identified in mouse lung fibrosis model. Gtse1 and Fgl1 are involved in radiation or TGFß-induced epithelial-mesenchymal transition. Radiation-induced fibrotic regions of mouse lungs showed increased expressions of Gtse1 and Fgl1. Gtse1 and Fgl1 are suggested to be novel targets for radiation-induced lung fibrosis.

Tumour-vasculature development via endothelial-to-mesenchymal transition after radiotherapy controls CD44v6+ cancer cell and macrophage polarization.

It remains controversial whether targeting tumour vasculature can improve radiotherapeutic efficacy. We report that radiation-induced endothelial-to-mesenchymal transition (EndMT) leads to tumour vasculature with abnormal SMA+NG2+ pericyte recruitment during tumour regrowth after radiotherapy. Trp53 (but not Tgfbr2) deletion in endothelial cells (ECs) inhibited radiation-induced EndMT, reducing tumour regrowth and metastases with a high CD44v6+ cancer-stem-cell (CSC) content after radiotherapy. Osteopontin, an EndMT-related angiocrine factor suppressed by EC-Trp53 deletion, stimulated proliferation in dormant CD44v6+ cells in severely hypoxic regions after radiation. Radiation-induced EndMT significantly regulated tumour-associated macrophage (TAM) polarization. CXCR4 upregulation in radioresistant tumour ECs was highly associated with SDF-1+ TAM recruitment and M2 polarization of TAMs, which was suppressed by Trp53 deletion. These EndMT-related phenomena were also observed in irradiated human lung cancer tissues. Our findings suggest that targeting tumour EndMT might enhance radiotherapy efficacy by inhibiting the re-activation of dormant hypoxic CSCs and promoting anti-tumour immune responses.

Metformin Alleviates Radiation-Induced Skin Fibrosis via the Downregulation of FOXO3.

BACKGROUND/AIMS: Radiation-induced skin fibrosis is a common side effect of clinical radiotherapy. Our previous next-generation sequencing (NGS) study demonstrated the reduced expression of the regulatory α subunit of phosphatidylinositol 3-kinase (PIK3r1) in irradiated murine skin. Metformin has been reported to target the PIK3-FOXO3 pathway. In this study, we investigated the effects of metformin on radiation-induced skin fibrosis. METHODS: Metformin was orally administered to irradiated mice. Skin fibrosis was analyzed by staining with H&E and Masson's trichrome stain. The levels of cytokines and chemokines associated with fibrosis were analyzed by immunohistochemistry and quantitative RT-PCR. The roles of PIK3rl and FOXO3 in radiation-induced skin fibrosis were studied by overexpressing PIK3rl and transfecting FOXO3 siRNA in NIH3T3 cells and mouse-derived dermal fibroblasts (MDF). RESULTS: The oral administration of metformin significantly reduced radiation-induced skin thickening and collagen accumulation and significantly reduced the radiation-induced expression of FOXO3 in murine skin. Additionally, the overexpression of PIK3r1 reduced the radiation-induced expression of FOXO3, while FOXO3 silencing decreased the radiation-induced expression of TGFß in vitro. CONCLUSIONS: The results indicated that metformin suppresses radiation-induced skin injuries by modulating the expression of FOXO3 through PIK3r1. Collectively, the data obtained in this study suggested that metformin could be a potent therapeutic agent for alleviating radiation-induced skin fibrosis.

HSP27 inhibitor attenuates radiation-induced pulmonary inflammation.

Radiation therapy has been used to treat over 70% of thoracic cancer; however, the method usually causes radiation pneumonitis. In the current study, we investigated the radioprotective effects of HSP27 inhibitor (J2) on radiation-induced lung inflammation in comparison to amifostine. In gross and histological findings, J2 treatment significantly inhibited immune cell infiltration in lung tissue, revealing anti-inflammatory potential of J2. Normal lung volume, evaluated by micro-CT analysis, in J2-treated mice was higher compared to that in irradiated mice. J2-treated mice reversed radiation-induced respiratory distress. However, amifostine did not show significant radioprotective effects in comparison to that of J2. In HSP27 transgenic mice, we observed increased immune cells recruitment and decreased volume of normal lung compared to wild type mice. Increased ROS production and oxidative stress after IR were down-regulated by J2 treatment, demonstrating antioxidant property of J2. The entire data of this study collectively showed that J2 may be an effective therapeutic agent for radiation-induced lung injury.

DJ-1 deficiency impairs synaptic vesicle endocytosis and reavailability at nerve terminals.

Mutations in DJ-1 (PARK7) are a known cause of early-onset autosomal recessive Parkinson's disease (PD). Accumulating evidence indicates that abnormalities of synaptic vesicle trafficking underlie the pathophysiological mechanism of PD. In the present study, we explored whether DJ-1 is involved in CNS synaptic function. DJ-1 deficiency impaired synaptic vesicle endocytosis and reavailability without inducing structural alterations in synapses. Familial mutants of DJ-1 (M26I, E64D, and L166P) were unable to rescue defective endocytosis of synaptic vesicles, whereas WT DJ-1 expression completely restored endocytic function in DJ-1 KO neurons. The defective synaptic endocytosis shown in DJ-1 KO neurons may be attributable to alterations in membrane cholesterol level. Thus, DJ-1 appears essential for synaptic vesicle endocytosis and reavailability, and impairment of this function by familial mutants of DJ-1 may be related to the pathogenesis of PD.