Hydrogel-based platforms for site-specific doxorubicin release in cancer therapy.

Hydrogels are promising candidates for the delivery of therapeutics in the treatment of human cancers. Regarding to the biocomaptiiblity, high drug and encapsulation efficacy and adjustable physico-chemical features, the hydrogels have been widely utilized for the delivery of chemotherapy drugs. Doxorubicin (DOX) is one of the most common chemotherapy drugs used in cancer therapy through impairing topoisomerase II function and increasing oxidative damage. However, the tumor cells have developed resistance into DOX-mediated cytotoxic impacts, requiring the delivery systems to increase internalization and anti-cancer activity of this drug. The hydrogels can deliver DOX in a sustained manner to maximize its anti-cancer activity, improving cancer elimination and reduction in side effects and drug resistance. The natural-based hydrogels such as chitosan, alginate and gelatin hydrogels have shown favourable biocompatibility and degradability in DOX delivery for tumor suppression. The hydrogels are able to co-deliver DOX with other drugs or genes to enhance drug sensitivity and mediate polychemotherapy, synergistically suppressing cancer progression. The incorporation of nanoparticles in the structure of hydrogels can improve the sustained release of DOX and enhancing intracellular internalization, accelerating DOX's cytotoxicity. Furthermore, the stimuli-responsive hydrogels including pH-, redox- and thermo-sensitive platforms are able to improve the specific release of DOX at the tumor site. The DOX-loaded hydrogels can be further employed in the clinic for the treatment of cancer patients and improving efficacy of chemotherapy.

The MT1 receptor as the target of ramelteon neuroprotection in ischemic stroke.

Stroke is the leading cause of death and disability worldwide. Novel and effective therapies for ischemic stroke are urgently needed. Here, we report that melatonin receptor 1A (MT1) agonist ramelteon is a neuroprotective drug candidate as demonstrated by comprehensive experimental models of ischemic stroke, including a middle cerebral artery occlusion (MCAO) mouse model of cerebral ischemia in vivo, organotypic hippocampal slice cultures ex vivo, and cultured neurons in vitro; the neuroprotective effects of ramelteon are diminished in MT1-knockout (KO) mice and MT1-KO cultured neurons. For the first time, we report that the MT1 receptor is significantly depleted in the brain of MCAO mice, and ramelteon treatment significantly recovers the brain MT1 losses in MCAO mice, which is further explained by the Connectivity Map L1000 bioinformatic analysis that shows gene-expression signatures of MCAO mice are negatively connected to melatonin receptor agonist like Ramelteon. We demonstrate that ramelteon improves the cerebral blood flow signals in ischemic stroke that is potentially mediated, at least, partly by mechanisms of activating endothelial nitric oxide synthase. Our results also show that the neuroprotection of ramelteon counteracts reactive oxygen species-induced oxidative stress and activates the nuclear factor erythroid 2-related factor 2/heme oxygenase-1 pathway. Ramelteon inhibits the mitochondrial and autophagic death pathways in MCAO mice and cultured neurons, consistent with gene set enrichment analysis from a bioinformatics perspective angle. Our data suggest that Ramelteon is a potential neuroprotective drug candidate, and MT1 is the neuroprotective target for ischemic stroke, which provides new insights into stroke therapy. MT1-KO mice and cultured neurons may provide animal and cellular models of accelerated ischemic damage and neuronal cell death.

Protection of melatonin in experimental models of newborn hypoxic-ischemic brain injury through MT1 receptor.

The function of melatonin as a protective agent against newborn hypoxic-ischemic (H-I) brain injury is not yet well studied, and the mechanisms by which melatonin causes neuroprotection in neurological diseases are still evolving. This study was designed to investigate whether expression of MT1 receptors is reduced in newborn H-I brain injury and whether the protective action of melatonin is by alterations of the MT1 receptors. We demonstrated that there was significant reduction in MT1 receptors in ischemic brain of mouse pups in vivo following H-I brain injury and that melatonin offers neuroprotection through upregulation of MT1 receptors. The role of MT1 receptors was further supported by observation of increased mortality in MT1 knockout mice following H-I brain injury and the reversal of the inhibitory role of melatonin on mitochondrial cell death pathways by the melatonin receptor antagonist, luzindole. These data demonstrate that melatonin mediates its neuroprotective effect in mouse models of newborn H-I brain injury, at least in part, by the restoration of MT1 receptors, the inhibition of mitochondrial cell death pathways and the suppression of astrocytic and microglial activation.

Gene expression profile analysis of U251 glioma cells with shRNA-mediated SOX9 knockdown.

PURPOSE: In glioma, the sex-determining region Y-box 9 gene (SOX9) is overexpressed and its downregulation leads to inhibition of cell proliferation, invasion and increased cell apoptosis. To further evaluate the molecular and signal pathways associated with the function of SOX9 and SOX9 target genes, a global gene expression profile of the established SOX9-knockdown U251 cells was investigated. METHODS: The molecular function and biological pathways of differentially expressed genes (DEGs) were identified by gene ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. The interactome networks of DEGs were constructed using the STRING online tool. The genes were further validated by RT-qPCR. RESULTS: GO analysis revealed that a set of 194 DEGs was shared in both the SOX9 KD-1 and SOX9 KD-2 U251 cells. GO analysis and KEGG pathway analysis showed that the DEGs were associated with biological processes involving cellular responses to hypoxia, osteoblast differentiation and angiogenesis, and special biological pathways, such as a TGF-beta signaling pathway and a HIF-1 signaling pathway. In addition, computational network of novel identified potential target genes linked to SOX9, including TGFB2, VEGFA, EGLN3 (PHD3), CA9 and HIF-1a. All of these genes were downregulated in the SOX9 knockdown U251 cells. CONCLUSIONS: SOX9 may be a key regulator impacting the glioma cellular processes by influencing the cellular response to hypoxia and HIF-1 signaling pathway. TGFB2, VEGFA, EGLN3 (PHD3), CA9, and HIF-1a may be the target genes of SOX9.

iRhom2 deficiency relieves TNF-α associated hepatic dyslipidemia in long-term PM2.5-exposed mice.

Accumulating researches reported that particulate matter (PM2.5) is a risk factor for developing various diseases, including metabolic syndrome. Recently, inactive rhomboid protein 2 (iRhom2) was considered as a necessary modulator for shedding of tumor necrosis factor-α (TNF-α) in immune cells. TNF-α, a major pro-inflammatory cytokine, was linked to various pathogenesis of diseases, including dyslipidemia. Here, wild type (WT) and iRhom2-knockout (iRhom2-/-) mice were used to investigate the effects of iRhom2 on PM2.5-induced hepatic dyslipidemia. The hepatic histology, inflammatory response, glucose tolerance, serum parameters and gene expressions were analyzed. We found that long-term inhalation of PM2.5 resulted in hepatic steatosis. And a significant up-regulation of iRhom2 in liver tissues was observed, accompanied with elevated TNF-α, TNF-α converting enzyme (TACE), TNFα receptor (TNFR)2 and various inflammatory cytokines expressions. Additionally, PM2.5 treatment caused TG and TC accumulation in serum and liver, probably attributed to changes of genes modulating lipid metabolism. Intriguingly, hepatic injury and dyslipidemia were attenuated by iRhom2-/- in mice with PM2.5 challenge. In vitro, iRhom2-knockdwon reduced TNF-α expressions and its associated inflammatory cytokines in Kupffer cells, implying that liver-resident macrophages played an important role in regulating hepatic inflammation and lipid metabolism in cells treated with PM2.5. The findings indicated that long-term PM2.5 exposure caused hepatic steatosis and dyslipidemia through triggering inflammation, which was, at least partly, dependent on iRhom2/TNF-α pathway in liver-resident macrophages.

N-acetyl-L-tryptophan delays disease onset and extends survival in an amyotrophic lateral sclerosis transgenic mouse model.

BACKGROUND: Whether L-NAT, a cytochrome c release inhibitor and an antagonist of NK-1R, provides protection in ALS is not known. RESULTS: L-NAT delays disease onset and mortality in mSOD1(G93A) ALS mice by inhibiting mitochondrial cell death pathways, inflammation, and NK-1R downregulation. CONCLUSION: L-NAT offers protection in a mouse model of ALS. SIGNIFICANCE: Data suggest the potential of L-NAT as a novel therapeutic strategy for ALS and provide insight into its action mechanisms. Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by progressive motor neuron loss, while inflammation has been implicated in its pathogenesis. Both inhibitors of cytochrome c release and antagonists of the neurokinin 1 receptor (NK-1R) have been reported to provide neuroprotection in ALS and/or other neurodegenerative diseases by us and other researchers. However, whether N-acetyl-L-tryptophan (L-NAT), an inhibitor of cytochrome c release and an antagonist of NK-1R, provides neuroprotection in ALS remains unknown. Here we demonstrate that the administration of L-NAT delayed disease onset, extended survival, and ameliorated deteriorations in motor performance in mSOD1(G93A) ALS transgenic mice. Our data showed that L-NAT reached the spinal cord, skeletal muscle, and brain. In addition, we demonstrate that L-NAT reduced the release of cytochrome c/smac/AIF, increased Bcl-xL levels, and inhibited the activation of caspase-3. L-NAT also ameliorated motor neuron loss and gross atrophy, and suppressed inflammation, as shown by decreased GFAP and Iba1 levels. Furthermore, we found gradually reduced NK-1R levels in the spinal cords of mSOD1(G93A) mice, while L-NAT treatment restored NK-1R levels. We propose the use of L-NAT as a potential therapeutic invention against ALS.

CLOCK/BMAL1 regulates circadian change of mouse hepatic insulin sensitivity by SIRT1.

UNLABELLED: The protein deacetylase, sirtuin 1 (SIRT1), involved in regulating hepatic insulin sensitivity, shows circadian oscillation and regulates the circadian clock. Recent studies show that circadian misalignment leads to insulin resistance (IR); however, the underlying mechanisms are largely unknown. Here, we show that CLOCK and brain and muscle ARNT-like protein 1 (BMAL1), two core circadian transcription factors, are correlated with hepatic insulin sensitivity. Knockdown of CLOCK or BMAL1 induces hepatic IR, whereas their ectopic expression attenuates hepatic IR. Moreover, circadian change of insulin sensitivity is impaired in Clock mutant, liver-specific Bmal1 knockout (KO) or Sirt1 KO mice, and CLOCK and BMAL1 are required for hepatic circadian expression of SIRT1. Further studies show that CLOCK/BMAL1 binds to the SIRT1 promoter to enhance its expression and regulates hepatic insulin sensitivity by SIRT1. In addition, constant darkness-induced circadian misalignment in mice decreases hepatic BMAL1 and SIRT1 levels and induces IR, which can be dramatically reversed by resveratrol. CONCLUSION: These findings offer new insights for coordination of the circadian clock and metabolism in hepatocytes by circadian regulation of hepatic insulin sensitivity via CLOCK/BMAL1-dependent SIRT1 expression and provide a potential application of resveratrol for combating circadian misalignment-induced metabolic disorders.

Nrf2 in human cancers: biological significance and therapeutic potential.

The nuclear factor-erythroid 2-related factor 2 (Nrf2) is able to control the redox balance in the cells responding to oxidative damage and other stress signals. The Nrf2 upregulation can elevate the levels of antioxidant enzymes to support against damage and death. In spite of protective function of Nrf2 in the physiological conditions, the stimulation of Nrf2 in the cancer has been in favour of tumorigenesis. Since the dysregulation of molecular pathways and mutations/deletions are common in tumors, Nrf2 can be a promising therapeutic target. The Nrf2 overexpression can prevent cell death in tumor and by increasing the survival rate of cancer cells, ensures the carcinogenesis. Moreover, the induction of Nrf2 can promote the invasion and metastasis of tumor cells. The Nrf2 upregulation stimulates EMT to increase cancer metastasis. Furthermore, regarding the protective function of Nrf2, its stimulation triggers chemoresistance. The natural products can regulate Nrf2 in the cancer therapy and reverse drug resistance. Moreover, nanostructures can specifically target Nrf2 signaling in cancer therapy. The current review discusses the potential function of Nrf2 in the proliferation, metastasis and drug resistance. Then, the capacity of natural products and nanostructures for suppressing Nrf2-mediated cancer progression is discussed.

Exploring non-coding RNA mechanisms in hepatocellular carcinoma: implications for therapy and prognosis.

Hepatocellular carcinoma (HCC) is a significant contributor to cancer-related deaths in the world. The development and progression of HCC are closely correlated with the abnormal regulation of non-coding RNAs (ncRNAs), such as microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs). Important biological pathways in cancer biology, such as cell proliferation, death, and metastasis, are impacted by these ncRNAs, which modulate gene expression. The abnormal expression of non-coding RNAs in HCC raises the possibility that they could be applied as new biomarkers for diagnosis, prognosis, and treatment targets. Furthermore, by controlling the expression of cancer-related genes, miRNAs can function as either tumor suppressors or oncogenes. On the other hand, lncRNAs play a role in the advancement of cancer by interacting with other molecules within the cell, which, in turn, affects processes such as chromatin remodeling, transcription, and post-transcriptional processes. The importance of ncRNA-driven regulatory systems in HCC is being highlighted by current research, which sheds light on tumor behavior and therapy response. This research highlights the great potential of ncRNAs to improve patient outcomes in this difficult disease landscape by augmenting the present methods of HCC care through the use of precision medicine approaches.

GARNL3 identified as a crucial target for overcoming temozolomide resistance in EGFRvIII-positive glioblastoma.

OBJECT: Amplification of the epidermal growth factor receptor (EGFR) and its active mutant type III (EGFRvIII), frequently occurr in glioblastoma (GBM), contributing to chemotherapy and radiation resistance in GBM. Elucidating the underlying molecular mechanism of temozolomide (TMZ) resistance in EGFRvIII GBM could offer valuable insights for cancer treatment. METHODS: To elucidate the molecular mechanisms underlying EGFRvIII-mediated resistance to TMZ in GBM, we conducted a comprehensive analysis using Gene Expression Omnibus and The cancer genome atlas (TCGA) databases. Initially, we identified common significantly differentially expressed genes (DEGs) and prioritized those correlating significantly with patient prognosis as potential downstream targets of EGFRvIII and candidates for drug resistance. Additionally, we analyzed transcription factor expression changes and their correlation with candidate genes to elucidate transcriptional regulatory mechanisms. Using estimate method and databases such as Tumor IMmune Estimation Resource (TIMER) and CellMarker, we assessed immune cell infiltration in TMZ-resistant GBM and its relationship with candidate gene expression. In this study, we examined the expression differences of candidate genes in GBM cell lines following EGFRvIII intervention and in TMZ-resistant GBM cell lines. This preliminary investigation aimed to verify the regulatory impact of EGFRvIII on candidate targets and its potential involvement in TMZ resistance in GBM. RESULTS: Notably, GTPase Activating Rap/RanGAP Domain Like 3 (GARNL3) emerged as a key DEG associated with TMZ resistance and poor prognosis, with reduced expression correlating with altered immune cell profiles. Transcription factor analysis suggested Epiregulin (EREG) as a putative upstream regulator of GARNL3, linking it to EGFRvIII-mediated TMZ resistance. In vitro experiments confirmed EGFRvIII-mediated downregulation of GARNL3 and decreased TMZ sensitivity in GBM cell lines, further supported by reduced GARNL3 levels in TMZ-resistant GBM cells. CONCLUSION: GARNL3 downregulation in EGFRvIII-positive and TMZ-resistant GBM implicates its role in TMZ resistance, suggesting modulation of EREG/GARNL3 signaling as a potential therapeutic strategy.

Reduced expression of SOCS2 and SOCS6 in hepatocellular carcinoma correlates with aggressive tumor progression and poor prognosis.

To investigate the clinical significance of suppressor of cytokine signaling (SOCS)-2 and SOCS6 in human hepatocellular carcinoma (HCC). The expression levels of SOCS2 and SOCS6 mRNA and protein in tumor, para-tumor and normal liver tissues were detected in 106 HCC patients by real-time quantitative RT-PCR (qRT-PCR) and Western blot. According to qRT-PCR and western blot analyses, we first found that both the expression levels of SOCS2 and SOCS6 mRNA and protein in HCC were significantly lower than those in para-tumor (both P < 0.001) and normal liver tissues (both P < 0.001). Then, the correlation analysis showed that both SOCS2 and SOCS6 protein downregulation were significantly correlated with advanced TNM stage (both P < 0.001) and high serum AFP (P = 0.008 and 0.01, respectively). Especially, the reduced expression of SOCS2 more frequently occurred in HCC patients with vascular invasion (P = 0.03), and that of SOCS6 was also associated with tumor recurrence (P = 0.01). Moreover, HCC patients with low expression of SOCS2 and SOCS6 had significantly shorter overall (P = 0.008 and 0.01, respectively) and disease-free survival (both P = 0.01). Furthermore, multivariate analysis showed that both SOCS2 and SOCS6 downregulation were independent prognostic factors of overall (P = 0.01 and 0.03, respectively) and disease-free survival (P = 0.01 and 0.03, respectively) in HCC. Our data demonstrate for the first time that SOCS2 and SOCS6 expression were remarkably reduced in HCC and may be served as potential prognostic markers for patients with this deadly disease.

Progress in building clinically relevant patient-derived tumor xenograft models for cancer research.

Patient-derived tumor xenograft (PDX) models, a method involving the surgical extraction of tumor tissues from cancer patients and subsequent transplantation into immunodeficient mice, have emerged as a pivotal approach in translational research, particularly in advancing precision medicine. As the first stage of PDX development, the patient-derived orthotopic xenograft (PDOX) models implant tumor tissue in mice in the corresponding anatomical locations of the patient. The PDOX models have several advantages, including high fidelity to the original tumor, heightened drug sensitivity, and an elevated rate of successful transplantation. However, the PDOX models present significant challenges, requiring advanced surgical techniques and resource-intensive imaging technologies, which limit its application. And then, the humanized mouse models, as well as the zebrafish models, were developed. Humanized mouse models contain a human immune environment resembling the tumor and immune system interplay. The humanized mouse models are a hot topic in PDX model research. Regarding zebrafish patient-derived tumor xenografts (zPDX) and patient-derived organoids (PDO) as promising models for studying cancer and drug discovery, zPDX models are used to transplant tumors into zebrafish as novel personalized medical animal models with the advantage of reducing patient waiting time. PDO models provide a cost-effective approach for drug testing that replicates the in vivo environment and preserves important tumor-related information for patients. The present review highlights the functional characteristics of each new phase of PDX and provides insights into the challenges and prospective developments in this rapidly evolving field.

FBLIM1 mRNA is a novel prognostic biomarker and is associated with immune infiltrates in glioma.

Glioma is the most common primary brain tumor. Filamin-binding LIM protein 1 (FBLIM1) has been identified in multiple cancers and is suspected of playing a part in the development of tumors. However, the potential function of FBLIM1 mRNA in glioma has not been investigated. In this study, the clinical information and transcriptome data of glioma patients were, respectively, retrieved from the TCGA and CGGA databases. The expression level of FBLIM1 mRNA was shown to be aberrant in a wide variety of malignancies. Significantly, when glioma samples were compared to normal brain samples, FBLIM1 expression was shown to be significantly elevated in the former. A poor prognosis was related to high FBLIM1 expression, which was linked to more advanced clinical stages. Notably, multivariate analyses demonstrated that FBLIM1 expression was an independent predictor for the overall survival of glioma patients. Immune infiltration analysis disclosed that FBLIM1 expression had relevance with many immune cells. The results of RT-PCR suggested that FBLIM1 expression was markedly elevated in glioma specimens. Functional experiments unveiled that the knockdown of FBLIM1 mRNA suppressed glioma cell proliferation. In general, we initially discovered that FBLIM1 mRNA might be a possible prognostic marker in glioma.

The application of Aptamer in biomarker discovery.

Biomarkers are detectable molecules that can reflect specific physiological states of cells, organs, and organisms and therefore be regarded as indicators for specific diseases. And the discovery of biomarkers plays an essential role in cancer management from the initial diagnosis to the final treatment regime. Practically, reliable clinical biomarkers are still limited, restricted by the suboptimal methods in biomarker discovery. Nucleic acid aptamers nowadays could be used as a powerful tool in the discovery of protein biomarkers. Nucleic acid aptamers are single-strand oligonucleotides that can specifically bind to various targets with high affinity. As artificial ssDNA or RNA, aptamers possess unique advantages compared to conventional antibodies. They can be flexible in design, low immunogenicity, relative chemical/thermos stability, as well as modifying convenience. Several SELEX (Systematic Evolution of Ligands by Exponential Enrichment) based methods have been generated recently to construct aptamers for discovering new biomarkers in different cell locations. Secretome SELEX-based aptamers selection can facilitate the identification of secreted protein biomarkers. The aptamers developed by cell-SELEX can be used to unveil those biomarkers presented on the cell surface. The aptamers from tissue-SELEX could target intracellular biomarkers. And as a multiplexed protein biomarker detection technology, aptamer-based SOMAScan can analyze thousands of proteins in a single run. In this review, we will introduce the principle and workflow of variations of SELEX-based methods, including secretome SELEX, ADAPT, Cell-SELEX and tissue SELEX. Another powerful proteome analyzing tool, SOMAScan, will also be covered. In the second half of this review, how these methods accelerate biomarker discovery in various diseases, including cardiovascular diseases, cancer and neurodegenerative diseases, will be discussed.

Liver Patt1 deficiency protects male mice from age-associated but not high-fat diet-induced hepatic steatosis.

Patt1 is a newly identified protein acetyltransferase that is highly expressed in liver. However, the role of Patt1 in liver is still unclear. We generated Patt1 liver-specific knockout (LKO) mice and mainly measured the effect of hepatic Patt1 deficiency on lipid metabolism. Hepatic Patt1 deficiency in male mice markedly decreases fat mass and dramatically alleviates age-associated accumulation of lipid droplets in liver. Moreover, hepatic Patt1 abrogation in male mice significantly reduces the liver triglyceride and free fatty acid levels, but it has no effect on liver cholesterol level, liver weight, and liver function. Consistently, primary cultured Patt1-deficient hepatocytes are resistant to palmitic acid-induced lipid accumulation, but hepatic Patt1 deficiency fails to protect male mice from high-fat diet-induced hepatic steatosis. Further studies show that hepatic Patt1 deficiency decreases fatty acid uptake, reduces lipid synthesis, and enhances fatty acid oxidation, which may contribute to the attenuated hepatic steatosis in Patt1 LKO mice. These results demonstrate that Patt1 plays an important role in hepatic lipid metabolism and have implications toward resolving age-associated hepatic steatosis.

Aberrant expression of N-methylpurine-DNA glycosylase influences patient survival in malignant gliomas.

AIM: To examine the expression of N-methylpurine-DNA glycosylase (MPG) gene and protein in glioma samples with different WHO grades and its association with patients' survival. METHODS: Immunohistochemistry assay, quantitative real-time PCR and Western blot analysis were carried out to investigate the expression of MPG gene and protein in 128 glioma and 10 non-neoplastic brain tissues. RESULTS: MPG gene expression level in glioma tissues was significantly higher than that in non-neoplastic brain tissues (P < 0.001). Immunohistochemistry also showed that MPG protein was over-expressed in glioma tissues, which was consistent with the resutls of Western blot analysis. Additionally, the expression levels of MPG gene and protein both increase from grade I to grade IV glioma according to the results of real-time PCR, immunohistochemistry and western blot analysis. Moreover, the survival rate of MPG-positive patients was significantly lower than that of MPG-negative patients (P < 0.001). We further confirmed that the over-expression of MPG was a significant and independent prognostic indicator in glioma by multivariate analysis (P < 0.001). CONCLUSIONS: Our data showed the over-expression of MPG gene and protein in human gliomas, and also suggested for the first time that MPG be an unfavorable independent prognostic indicator for glioma patients.

Down-regulation of Nedd4L is associated with the aggressive progression and worse prognosis of malignant glioma.

OBJECTIVE: Human neural precursor cell-expressed developmentally down-regulated 4 like (Nedd4L), a ubiquitin protein ligase, is expressed by various cancer cells and might have an oncogenic property. Its expression pattern in glioma tissues is unknown. Therefore, the aim of this study was to investigate whether Nedd4L is present in glioma and to evaluate the correlation of Nedd4L expression with the progression and prognosis of the disease. METHODS: Immunohistochemistry and western blot were used to investigate the expression of Nedd4L protein in 128 patients with gliomas. RESULTS: Immunohistochemistry showed a strong-to-weak range of Nedd4L staining with increasing pathologic grade of glioma (P < 0.001), which was in line with the results from western blot analysis. In addition, a non-parametric analysis revealed that the attenuated Nedd4L expression was significantly correlated with a large tumor diameter (P = 0.02), low Karnofsky performance score (P = 0.008), frequent intra-tumor necrosis (P = 0.01) and worse overall survival (P = 0.009). Furthermore, multivariate analysis showed that Nedd4L expression (P = 0.02) and intra-tumor necrosis (P = 0.03) were two important independent prognostic factors identified by the Cox proportional hazards model. CONCLUSIONS: Our results provide convincing evidence for the first time that the expression of Nedd4L is down-regulated in human gliomas. The glioma patients with lower Nedd4L expression have a worse prognosis.

Strong inhibition of celastrol towards UDP-glucuronosyl transferase (UGT) 1A6 and 2B7 indicating potential risk of UGT-based herb-drug interaction.

Celastrol, a quinone methide triterpene isolated from Tripterygium wilfordii Hook F., has various biochemical and pharmacological activities, and is now being developed as a promising anti-tumor agent. Inhibitory activity of compounds towards UDP-glucuronosyltransferase (UGT) is an important cause of clinical drug-drug interactions and herb-drug interactions. The aim of the present study is to investigate the inhibition of celastrol towards two important UDP-glucuronosyltransferase (UGT) isoforms UGT1A6 and UGT2B7. Recombinant UGT isoforms and non-specific substrate 4-methylumbelliferone (4-MU) were used. The results showed that celastrol strongly inhibited the UGT1A6 and 2B7-mediated 4-MU glucuronidation reaction, with 0.9 ± 0.1% and 1.8 ± 0.2% residual 4-MU glucuronidation activity at 100 µM of celastrol, respectively. Furthermore, inhibition kinetic study (Dixon plot and Lineweaver-Burk plot) demonstrated that celastrol noncompetitively inhibited the UGT1A1-mediated 4-MU glucuronidation, and competitively inhibited UGT2B7-catalyzed 4-MU glucuronidation. The inhibition kinetic parameters (Ki) were calculated to be 0.49 µM and 0.045 µM for UGT1A6 and UGT2B7, respectively. At the therapeutic concentration of celastrol for anti-tumor utilization, the possibility of celastrol-drug interaction and celastrol-containing herbs-drug interaction were strongly indicated. However, given the complicated nature of herbs, these results should be viewed with more caution.

Gossypol exhibits a strong influence towards UDP-glucuronosyltransferase (UGT) 1A1, 1A9 and 2B7-mediated metabolism of xenobiotics and endogenous substances.

Gossypol, the polyphenolic constituent isolated from cottonseeds, has been used as a male antifertility drug for a long time, and has been demonstrated to exhibit excellent anti-tumor activity towards multiple cancer types. The toxic effects of gossypol limit its clinical utilization, and enzyme inhibition is an important facet of this. In the present study, in vitro human liver microsomal incubation system supplemented with UDPGA was used to investigate the inhibition of gossypol towards UGT1A1, 1A9 and 2B7-mediated metabolism of xenobiotics and endogenous substances. Estradiol, the probe substrate of UGT1A1, was selected as representative endogenous substance. Propofol (a probe substrate of UGT1A9) and 3'-azido-3'-deoxythimidine (AZT, a probe substrate of UGT2B7) were employed as representative xenobiotics. The results showed that gossypol noncompetitively inhibits UGT-mediated estradiol-3-glucuronidation and propofol O-glucuronidation, and the inhibition kinetic parameters (K(i)) were calculated to be 34.2 and 16.4 µM, respectively. Gossypol was demonstrated to exhibit competitive inhibition towards UGT-mediated AZT glucuronidation, and the inhibition kinetic parameter (K(i)) was determined to be 14.0 µM. All these results indicated that gossypol might induce metabolic disorders of endogenous substances and alteration of metabolic behaviour of co-administered xenobiotics through inhibition of UGTs' activity.

Inhibition potential of glimepiride (gli) towards important UDP-glucuronosyltransferase (UGT) isoforms in human liver.

The aim of the present study was to investigate the inhibitory potential of glimepiride towards important UDP-glucuronosyltransferase (UGT) isoforms in human liver, which play a key role in the elimination of drugs. The recombinant UGT enzymes were used as enzyme source, and a nonspecific substrate 4-methylumbelliferone (4-MU) was utilized as substrate. The results showed that 100 microM of glimepiride inhibited UGT1A1, UGT1A3, UGT1A6, UGT1A9, UGT2B7 and UGT2B15 by 54.7%, 43.1%, 100%, 70.5%, 32.7 and 37.2%, respectively. Given that glimepiride exhibited strong inhibition towards UGT1A6, further inhibitory kinetic behaviour was determined. Glimepiride exerted concentration-dependent inhibition towards UGT1A6. Both Dixon and Lineweaver-Burk plots demonstrated that inhibition of UGT1A6 was best fit for noncompetitive inhibition type, and the inhibition kinetic parameter (Ki) was calculated to be 59.8 microM. Given that UGT1A6 plays a key role in detoxification of many drugs, more attention should be given when glimepiride was co-administered with the drugs mainly undergoing UGT1A6-mediated metabolism.