MXene-Bimetallic Hybrids via Mixed Molten Salts Etching for Kinetics-Enhanced and Dendrite-Free Lithium-Sulfur Batteries.

Lithium-sulfur (Li-S) batteries with high theoretical energy density (2600 Wh kg-1) are considered to be one of the most promising secondary batteries. However, the practical application of Li-S batteries is limited by the polysulfides shuttling and unstable lithium metal anodes. Herein, an asymmetric separator (CACNM@PP), composed of Co-Ni/MXene (CNM) on the cathode and Cu-Ag/MXene (CAM) on the anode for high-performance Li-S batteries is reported. For the cathode, CNM provides a synergistic effect by integrating Co, Ni, and MXene, resulting in strong chemical interactions and fast conversion kinetics for polysulfides. For the anode, CAM with abundant lithiophilicity active sites can lower the nucleation barrier of Li. Moreover, LiCl/LiF layers are generated in situ as an ion conductor layer during charging and discharging, inducing a uniform deposition of Li. Therefore, the assembled cells with the CACNM@PP separators harvest excellent electrochemical performance. This work provides novel insights into the development of commercially available high-energy density Li-S batteries with asymmetric separators.

CoAl-LDH decorated with cerium oxide as an efficient adsorbent for restoring low-concentration phosphate in wastewater.

The requirement for the removal of phosphorus (P) from wastewater has become progressively stringent, therefore, it is essential to remove low-concentration phosphate from secondary effluents through a tertiary treatment. One of the biggest challenges in removing phosphate from wastewater is the development of low-cost, green, and pollution-free adsorbents. In this study, novel, eco-friendly and low-cost CeO2 nanosphere modifying CoAl-LDH nanosheets (CoAl-LDH/CeO2) were successfully fabricated using a classical hydrothermal strategy. The microstructure and morphology of CoAl LDH/CeO2 were characterized using SEM, TEM, FTIR, XRD, TG, XPS, and BET techniques. The performance of the P adsorption from water for CoAl-LDH/CeO2 was investigated. The influences of adsorption parameters, such as adsorbent dosage, pH, phosphate concentration, adsorption time, and experimental temperature, were investigated through batch adsorption experiments. The batch adsorption experiments showed that the P removal by CoAl-LDH/CeO2 could reach 93.4% at room temperature within 60 minutes. CoAl-LDH/CeO2 showed ultrafast and high-efficiency adsorption for low concentration P contaminated wastewater. Pseudo-second order model exhibited better fitting with the kinetics of the phosphate adsorption, while the Freundlich model well-described the isotherm results (R2 > 0.999). Although Cl-, NO3-and SO42- coexisted in the solution, CoAl-LDH/CeO2 still possessed favourable selectivity for phosphates. More importantly, the adsorption capacities of CoAl-LDH/CeO2 retained over 85% after five cycles. Therefore, the low cost and sustainable utilization of CoAl-LDH/CeO2 for the phosphate removal from secondary effluent with phosphate at a low concentration highlights its potential application to alleviate eutrophication.

Methylated Biochemical Fulvic Acid-Derived Hydrogels with Improved Swelling Behavior and Water Retention Capacity.

Although humic acids (HAs) have been used to prepare absorbent hydrogels, their applications in many areas, such as agriculture, wastewater treatment and hygienic products, are not satisfactory due to their low solubility in organic solvents. In this work, biochemical fulvic acid (BFA), as a kind of HA, was initially methylated for preparation of the methylated BFA (M-BFA), which contributed to enhancing the solubility in organic solvents. Then, M-BFA reacted with N,N'-methylene diacrylamide (MBA) in the N,N-Dimethylacrylamide (DMAA) solution, and the expected hydrogel (M-BFA/DMAA) was successfully obtained. XPS confirmed that there were more C=O and C-N groups in M-BFA/DMAA than in DMAA; thus, M-BFA/DMAA was able to offer more reactive sites for the water adsorption process than DMAA. The combined results of BET and SEM further demonstrated that M-BFA/DMAA possessed a larger BET surface area, a larger pore volume and a more porous structure, which were favorable for the transfer of water and accessibility of water to active sites, facilitating water adsorption and storage. In addition, the swelling ratio and water retention were investigated in deionized (DI) water at different conditions, including test times, temperatures and pHs. Amazingly, the swelling ratio of M-BFA/DMAA was 10% higher than that of DMAA with the water retention time from 100 to 1500 min. Although M-BFA/DMAA and DMAA had similar temperature sensitivities, the pH sensitivity of M-BFA/DMAA was 0.9 higher than that of DMAA. The results proved that M-BFA/DMAA delivered superior water retention when compared to the pristine DMAA. Therefore, the resultant materials are expected to be efficient absorbent materials that can be widely used in water-deficient regions.

TGF-ß1 dominates stromal fibroblast-mediated EMT via the FAP/VCAN axis in bladder cancer cells.

BACKGROUND: Bladder cancer is one of the most common malignant tumors of the urinary system and is associated with a poor prognosis once invasion and distant metastases occur. Epithelial-mesenchymal transition (EMT) drives metastasis and invasion in bladder cancer. Transforming growth factor ß1 (TGF-ß1) and stromal fibroblasts, especially cancer-associated fibroblasts (CAFs), are positive regulators of EMT in bladder cancer. However, it remains unclear how TGF-ß1 mediates crosstalk between bladder cancer cells and CAFs and how it induces stromal fibroblast-mediated EMT in bladder cancer. We aimed to investigate the mechanism of TGF-ß1 regulation of stromal fibroblast-mediated EMT in bladder cancer cells. METHODS: Primary CAFs with high expression of fibroblast activation protein (FAP) were isolated from bladder cancer tissue samples. Subsequently, different conditioned media were used to stimulate the bladder cancer cell line T24 in a co-culture system. Gene set enrichment analysis, a human cytokine antibody array, and cytological assays were performed to investigate the mechanism of TGF-ß1 regulation of stromal fibroblast-mediated EMT in bladder cancer cells. RESULTS: Among the TGF-ß family, TGF-ß1 was the most highly expressed factor in bladder cancer tissue and primary stromal fibroblast supernatant. In the tumor microenvironment, TGF-ß1 was mainly derived from stromal fibroblasts, especially CAFs. In stimulated bladder cells, stromal fibroblast-derived TGF-ß1 promoted bladder cancer cell migration, invasion, and EMT. Furthermore, TGF-ß1 promoted the activation of stromal fibroblasts, inducing CAF-like features, by upregulating FAP in primary normal fibroblasts and a normal fibroblast cell line. Stromal fibroblast-mediated EMT was induced in bladder cancer cells by TGF-ß1/FAP. Versican (VCAN), a downstream molecule of FAP, plays an essential role in TGF-ß1/FAP axis-induced EMT in bladder cancer cells. VCAN may also function through the PI3K/AKT1 signaling pathway. CONCLUSIONS: TGF-ß1 is a critical mediator of crosstalk between stromal fibroblasts and bladder cancer cells. We revealed a new mechanism whereby TGF-ß1 dominated stromal fibroblast-mediated EMT of bladder cancer cells via the FAP/VCAN axis and identified potential biomarkers (FAP, VCAN, N-cadherin, and Vimentin) of bladder cancer. These results enhance our understanding of bladder cancer invasion and metastasis and provide potential strategies for diagnosis, treatment, and prognosis.

Texture synthesis of ecological plant protection image based on convolution neural network.

Texture synthesis technology is an important realistic rendering technology. Texture synthesis technology also has a good application prospect in image rendering and other fields. Convolutional neural network is a very popular technology in recent years. Convolutional neural network model can learn the features in data and realize intelligent processing through the feature learning in data. Later, with the rapid improvement of convolutional neural network, texture synthesis technology based on neural network came into being. The purpose of this paper is to study the texture synthesis method of ecological plant protection image based on convolutional neural network. By studying the context and research implications, the definition of textures as well as texture synthesis methods, convolutional neural networks, and based on convolutional neural network. In the experiment, the experimental environment is established, and the subjective evaluation and objective evaluation of the image texture synthesis method experiment are investigated and studied by using swap algorithm. The experimental results show that the method used in this paper is superior to other methods.

Multilayer Graphene Oxide Supported ZIF-8 for Efficient Removal of Copper Ions.

To address the performance deterioration of ZIF-8 for the adsorption of copper ions caused by powder volume pressure and particle aggregation, we employed multilayer graphene oxide (MGO) as a support to prepare composite adsorbents (MGO@ZIF-8) by using the in situ growth of ZIF-8 on MGO. Due to a good interfacial compatibility and affinity between ZIF-8 and graphene nanosheets, the MGO@ZIF-8 was successfully prepared. The optimal Cu2+ adsorption conditions of MGO@ZIF-8 were obtained through single factor experiments and orthogonal experiments. Surprisingly, the Cu2+ adsorption capacity was significantly improved by the integration of MGO and ZIF-8, and the maximum Cu2+ adsorption capacity of MGO@ZIF-8 reached 431.63 mg/g under the optimal adsorption conditions. Furthermore, the kinetic fitting and isotherm curve fitting confirmed that the adsorption law of Cu2+ by MGO@ZIF-8 was the pseudo-second-order kinetic model and the Langmuir isotherm model, which indicated that the process of Cu2+ adsorption was monolayer chemisorption. This work provides a new approach for designing and constructing ZIF-8 composites, and also offers an efficient means for the removal of heavy metals.

Acupuncture-related therapies for the poststroke cognitive impairment patients: A protocol for systematic review and network meta-analysis.

BACKGROUND: To compare and rank the clinical effects of different acupuncture and acupuncture-related therapies on patients with poststroke cognitive impairment. METHODS: We evaluated the direct and indirect evidence from relevant studies using network meta-analysis. Eight databases were examined in order to find randomized controlled trials of acupuncture-related therapies for individuals with poststroke cognitive impairment. After 2 researchers independently scanned the literature, extracted the data, and assessed the risk of bias in the included studies, the data were analyzed using RevMan5.4, Stata15.0, and WinBUGS1.4.3 software. RESULTS: We assess the benefits and drawbacks of various acupuncture-related therapies, rank the efficacy of various acupuncture-related therapies in the treatment of poststroke cognitive impairment, and describe the best acupuncture intervention approaches or combinations based on the available data. CONCLUSION: This study will contribute to the existence of data on the safety and efficacy of acupuncture-related therapies in the treatment of poststroke cognitive impairment, and it may aid clinical guideline makers in selecting the best acupuncture treatment for poststroke cognitive impairment. REGISTRATION NUMBER: INPLASY2021120117.

Three-Dimensional Porous Network Electrodes with Cu(OH)2 Nanosheet/Ni3S2 Nanowire 2D/1D Heterostructures for Remarkably Cycle-Stable Supercapacitors.

Developing advanced electrode materials with highly improved charge and mass transfer is critical to obtain high specific capacities and long-term cycle life for energy storage. Herein, three-dimensionally (3D) porous network electrodes with Cu(OH)2 nanosheets/Ni3S2 nanowire 2D/1D heterostructures are rationally fabricated. Different from traditional surface deposition, the 1D/2D heterostructure network is obtained by in situ hydrothermal chemical etching of the surface layer of nickel foam (NF) ligaments. The Cu(OH)2/Ni3S2@NF electrode delivers a high specific capacity (1855 F g-1 at 2 mA cm-2) together with a remarkable stability. The capacity retention of the electrode is over 110% after 35,000 charge/discharge cycles at 20 mA cm-2. The improved performance is attributed to the enhanced electron transfer between 1D Ni3S2 and 2D Cu(OH)2, highly accessible sites of 3D network for electrolyte ions, and strong mechanical bonding and good electrical connection between Cu(OH)2/Ni3S2 active materials and the conductive NF. Especially, the unique 1D/2D heterostructure alleviates structural pulverization during the ion insertion/desertion process. A symmetric device applying the Cu(OH)2/Ni3S2@NF electrode exhibits a remarkable cycling stability with the capacitance retention maintaining over 98% after 30,000 cycles at 50 mA cm-2. Therefore, the outstanding performance promises the architectural 1D/2D heterostructure to offer potential applications in future electrochemical energy storage.

Long noncoding RNA NORAD acts as a ceRNA mediates gemcitabine resistance in bladder cancer by sponging miR-155-5p to regulate WEE1 expression.

BACKGROUND: Increasing evidences have proved that long noncoding RNAs (lncRNAs) regulate the occurrence of bladder cancer (BC) and participate in various pathophysiology processes. However, little is unknown about the role of lncRNAs in drug resistance of BC cells. In this study, we explored the role of non-coding RNA activated by DNA damage (NORAD) in the gemcitabine (GEM) resistant of BC cells and explored its potential mechanism. METHODS: Real-time quantitative PCR (RT-qPCR) was used to detect the expression of NORAD and miR-155-5p of BC cells. Cell counting kit-8 (CCK-8) and Western blot were used to detect cell inhibition rate and the expression of WEE1 G2 checkpoint kinase (WEE1), P-glycoprotein (P-gp) and multidrug resistance-associated protein 1 (MRP1). Flow cytometry detected cell cycle and apoptosis. Dual luciferase reporter gene assay and RNA immunoprecipitation (RIP) assay were used to confirm the targeting relationship between miR-155-5p, NORAD and WEE1. The xenograft model was used to observe the function of NORAD in vivo. immunohistochemistry (IHC) assay was used to detect the expression of WEE1, caspase-3 and Ki67 in tumor tissues. RESULTS: NORAD highly expressed in GEM-resistant BC cell lines. Knockdown of NORAD significantly inhibited the proliferation of T24/GEM cells, the expression of drug-resistant proteins P-gp and MRP1, inhibit the G0/G1 phase of cells, and induce cell apoptosis. Knockdown of NORAD reversed the promotion effect of miR-155-5p on WEE1 expression and promoted the sensitivity of T24/GEM cells to GEM. In vivo, knockdown of NORAD inhibited the tumor growth, and enhanced the GEM-sensitivity in mice. CONCLUSION: These data highlight the potential of NORAD acts as a therapeutic target for BC GEM resistance. It revealed the vital roles of NORAD/miR-155-5p/WEE1 axis in GEM resistant BC cells, providing a novel therapeutic strategy for BC.

The thermogenic activity of adjacent adipocytes fuels the progression of ccRCC and compromises anti-tumor therapeutic efficacy.

Clear cell renal cell carcinoma (ccRCC) preferentially invades into perinephric adipose tissue (PAT), a process associated with poor prognosis. However, the detailed mechanisms underlying this interaction remain elusive. Here, we describe a bi-directional communication between ccRCC cells and the PAT. We found that ccRCC cells secrete parathyroid-hormone-related protein (PTHrP) to promote the browning of PAT by PKA activation, while PAT-mediated thermogenesis results in the release of excess lactate to enhance ccRCC growth, invasion, and metastasis. Further, tyrosine kinase inhibitors (TKIs) extensively used in the treatment of ccRCC enhanced this vicious cycle of ccRCC-PAT communication by promoting the browning of PAT. However, if this cross-communication was short circuited by the pharmacological suppression of adipocyte browning via H89 or KT5720, the anti-tumor efficacy of the TKI, sunitinib, was enhanced. These results suggest that ccRCC-PAT cross-communication has important clinical relevance, and use of combined therapy holds great promise in enhancing the efficacy of TKIs.

Myricitrin protects against cisplatin-induced kidney injury by eliminating excessive reactive oxygen species.

BACKGROUND: Cisplatin could result in a wide range of kidney injuries. During the pathogenetic process, the excessive generation of reactive oxygen species (ROS) induced by cisplatin has been regarded as the initial and critical role, by which DNA damage and cell death could subsequently come up. Therefore the elimination of ROS has long been considered as effective mean to prevent cisplatin-induced kidney injury. Myricitrin is a newfound natural polyphenol hydroxy flavonoid glycoside compound, whose forceful anti-oxidative properties had been confirmed. Thus, we aim to investigate if myricitrin could protect against cisplatin-induced kidney injury. METHODS: A cisplatin-induced kidney injury model was established in mice by intraperitoneal injection of cisplatin. The protective effect of myricitrin on kidney injury was evaluated by serum BUN and Cre level. The Kidney pathology was observed with H&E and TUNEL staining. Then cell viability and apoptosis rate were measured using MMT assay and flow cytometry to assess if myricitrin could protect KH-2 cells against cisplatin-induced injury. The intracellular ROS was detected by ROS fluorogenic probe and quantitatively analyzed by flow cytometry. Finally, the expression of Bcl-2 and Bax was investigated by western blotting to indicate the influence in apoptosis pathway. RESULTS: Myricitrin could significantly remit kidney injury induced by cisplatin and inhibit apoptosis of KH-2 cells. In mechanism, myricitrin could eliminate ROS and subsequently block activation of apoptosis pathway. CONCLUSION: Myricitrin protects against cisplatin-induced kidney injury by eliminating excessive ROS.

Overexpression of lncRNA ANRIL promoted the proliferation and migration of prostate cancer cells via regulating let-7a/TGF-ß1/ Smad signaling pathway.

Long non-coding RNAs (lncRNAs) were playing critical roles in tumorigenesis. However, in prostate cancer, the roles and mechanisms of lncRNAs especially ANRIL were largely unknown. We investigated the effects of ANRIL on the proliferation and migration of prostate cancer cells using CCK-8 assay and Transwell migration assay. Real-time PCR and western blotting assays were used to analyze the levels of ANRIL, let-7a, TGF-ß1, p-Smad2 and p-Smad7. Our results showed that ANRIL was significantly overexpressed in prostate cancer tissues compared with corresponding normal tissues. Knockdown of ANRIL significantly inhibited the proliferation and migration of prostate cancer LNCap, PC3 and DU145 cells. Knockdown of ANRIL significantly decreased the levels of TGF-ß1 and p-Smad2, and increased the level of p-Smad7 in prostate cancer LNCap cells. We further found that knockdown of ANRIL significantly enhanced the expression of let-7a, and rescue experiment found that let-7a inhibitor recovered the suppressive effects of ANRIL silencing on the proliferation and migration of prostate cancer LNCap, PC3 and DU145 cells. And let-7a inhibitor recovered the suppressive effects of ANRIL silencing on the activity of TGF-ß1/Smad signaling pathway in prostate cancer LNCap cells. Taken together, our findings indicated that overexpression of lncRNA ANRIL promoted the proliferation and migration of prostate cancer cells via regulating let-7a/TGF-ß1/Smad signaling pathway.

Inhibition of Gli1-mediated prostate cancer cell proliferation by inhibiting the mTOR/S6K1 signaling pathway.

Ectopic activation of the canonical Hedgehog signaling pathway is involved in the development and progression of prostate cancer, which is one of the leading causes of cancer-associated mortality in males worldwide. However, the role of the non-canonical Hedgehog signaling pathway in prostate cancer remains generally unexplored. In the present study, it was identified that Gli (glioma-associated oncogene)1 and Gli2 were highly expressed at the protein level in the androgen-independent prostate cancer cell lines PC3 and DU145, but not in the androgen-dependent cancer cell line LNCaP. Silencing of Gli1 using small interfering RNA markedly decreased PC3 cell viability and liquid colony formation in vitro. The Gli1/2-specific inhibitor GANT61 markedly decreased cell viability by inducing cell apoptosis in PC3 and DU145 cells. GANT61 also alleviated liquid colony formation efficiency in PC3 and DU145 cells, suggesting that the activity of Gli1 is required for prostate cancer cell survival. To explore further the upstream signaling pathway involved in the regulation of Gli1 expression, it was identified that tumor necrosis factor α-triggered mammalian target of rapamycin (mTOR)/p70 ribosomal protein S6 kinase 1 (S6K1) activation was required for Gli1 expression. Pharmacological and genetic inhibition of S6K1 activation markedly decreased Gli1 and its downstream target gene mRNA expression. In addition, the phosphoinositide 3-kinase/mTOR inhibitor BEZ235 markedly decreased in vitro PC3 cell proliferation. The results of the present study indicate that the non-canonical Hedgehog pathway (mTOR/S6K1/Gli1) contributes to the development and progression of prostate cancer and that Gli1 is a potential therapeutic target in the treatment of prostate cancer.

Androgenic to oestrogenic switch in the human adult prostate gland is regulated by epigenetic silencing of steroid 5α-reductase 2.

Benign prostatic hyperplasia is the most common proliferative abnormality of the prostate. All men experience some prostatic growth as they age, but the rate of growth varies among individuals. Steroid 5α-reductase 2 (SRD5A2) is a critical enzyme for prostatic development and growth. Previous work indicates that one-third of adult prostatic samples do not express SRD5A2, secondary to epigenetic modifications. Here we show that the level of oestradiol is dramatically elevated, concomitant with significant upregulation of oestrogen response genes, in prostatic samples with methylation at the SRD5A2 promoter. The phosphorylation of oestrogen receptor-α in prostatic stroma is upregulated when SRD5A2 expression is absent. We show that tumour necrosis factor (TNF)-α suppresses SRD5A2 mRNA and protein expression, and simultaneously promotes expression of aromatase, the enzyme responsible for conversion of testosterone to oestradiol. Concomitant suppression of SRD5A2 and treatment with TNF-α synergistically upregulate the aromatase levels. The data suggest that, in the absence of prostatic SRD5A2, there is an androgenic to oestrogenic switch. These findings have broad implications for choosing appropriate classes of medications for the management of benign and malignant prostatic diseases. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Inhibitory effects of resveratrol on the adhesion, migration and invasion of human bladder cancer cells.

Resveratrol is a polyphenolic compound, which has been revealed to induce apoptosis in numerous human cancer cells; however, the effects of resveratrol on the migration and invasion of human bladder cancer cells have not been reported. The present study aimed to evaluate the anti­metastatic potential of resveratrol against bladder cancer and its mechanism of action. The results indicated that resveratrol inhibits the adhesion, migration and invasion of bladder cancer cells in a dose­dependent manner. Resveratrol was shown to significantly inhibit the expression and secretion of matrix metalloproteinase (MMP)­2 and MMP­9 in bladder cancer cells. Furthermore, resveratrol suppressed the phosphorylation of c­Jun N­terminal kinase and extracellular signal­regulated protein kinase. In conclusion, the present study is the first, to the best of our knowledge, to demonstrate that resveratrol may be considered a novel anticancer agent for the treatment of bladder cancer via the inhibition of migration and invasion.

Mesoporous SBA-15 Silica-supported Diisopropylguanidine: an Efficient Solid Catalyst for Interesterification of Soybean Oil with Methyl Octanoate or Methyl Decanoate.

The organosilane agent, namely 3-(N,N'-diisopropylguanidine)-propyltriethoxysilane, was firstly prepared by the reaction of diisopropylcarbodimide with (3-aminopropyl)triethoxysilane, and then employed for grafting guanidine base onto the surface of the mesoporous SBA-15 silica to afford an organic-inorganic hybrid catalyst. The prepared solid catalyst was fully characterized by various techniques such as small-angle X-ray power diffraction, Fourier transform infrared spectra, scanning electron microscopy, transmission electron microscopy, nitrogen adsorption-desorption and elemental analysis techniques. The obtained results showed that the guanidine base was successfully tethered onto the SBA-15 silica and the ordered mesoporous structure of the SBA-15 material remained almost unchangeable after the orgnofunctionalization. The solid catalyst was found to have appreciable catalytic activities to the interesterification of soybean oil with methyl octanoate or methyl decanoate under solvent-free conditions. Influence of various reaction parameters, such as the substrate molar ratio, reaction temperature, catalyst loading and reaction time, on the catalytic interesterification was investigated to optimize the interesterification condition for the production of structured lipids containing medium-chain fatty acids. The hybrid solid catalyst was easily separated and reused for four runs without significant loss of catalytic activity.

Biguanide-functionalized mesoporous SBA-15 silica as an efficient solid catalyst for interesterification of vegetable oils.

The biguanide-functionalized SBA-15 materials were fabricated by grafting of organic biguanide onto the SBA-15 silica through covalent attachments, and then this organic-inorganic hybrid material was employed as solid catalysts for the interesterification of triacylglycerols for the modification of vegetable oils. The prepared catalyst was characterized by FTIR, XRD, SEM, TEM, nitrogen adsorption-desorption and elemental analysis. The biguanide base was successfully tethered onto the SBA-15 silica with no damage to the ordered mesoporous structure of the silica after the organo-functionalization. The solid catalyst had stronger base strength and could catalyze the interesterification of triacylglycerols. The fatty acid compositions and triacylglycerol profiles of the interesterified products were noticeably varied following the interesterification. The reaction parameters, namely substrate ratio, reaction temperature, catalyst loading and reaction time, were investigated for the interesterification of soybean oil with methyl decanoate. The catalyst could be reused for at least four cycles without significant loss of activity.

Reduced levels of 5-α reductase 2 in adult prostate tissue and implications for BPH therapy.

BACKGROUND: 5-α reductase 2 (5-AR 2) is a key enzyme that is responsible of proper development of prostate tissue. Inhibition of 5-AR 2 has proven to be efficacious for management of urinary symptoms secondary benign prostatic hyperplasia (BPH). However, some patients are resistant to the therapeutic effects of 5-AR 2 inhibitor. We wished to determine why some benign non-cancerous adult human prostates do not express 5-AR 2, and hypothesized that methylation of 5-AR 2 promoter region correlated with low expression of 5-AR 2 protein. METHODS: The transition zone of 42 human prostate tissues after radical prostatectomy was used for evaluation. Initially, 21 paraffin embedded samples were used to assess immunoreactivity to 5-AR 2 antibody in non-cancerous BPH samples. In the next 21 samples, fresh frozen prostate transition zone samples without cancer were assessed for immunoreactivity and methylation of the 5-AR 2 promoter using methyl-specific PCR. RESULTS: We show that 6/21 (29%) of benign human prostate samples did not express the 5-AR 2 protein. Moreover, the promoter region of 5-AR 2 contains a CpG island that is methylated in benign prostate epithelial cells in culture and also in 39% (7/18) human prostate tissues. We show a strong correlation between methylation of the 5-AR 2 promoter region and absence of 5-AR 2 protein expression (P = 0.0025, Fisher's exact test). CONCLUSIONS: Methylation of 5-AR 2 promoter may account for low or absent expression of 5-AR 2 in some human adult prostate tissues.

Phosphatidylinositol 3-kinase/protein kinase B pathway stabilizes DNA methyltransferase I protein and maintains DNA methylation.

DNA methylation, which affects gene expression and chromatin stability, is catalyzed by DNA methyltransferases (DNMTs) of which DNMT1 possesses most abundant activity. PI3K/PKB pathway is an important pathway involved in cell proliferation, viability, and metabolism and often disrupted in cancer. Here we investigated the impact of PKB on DNMT1 and DNA methylation. Positive correlation between PKB-Ser473-phosphorylation and DNMT1 protein level in 17 human cell lines (p<0.01) and in 27 human bladder cancer tissues (p<0.05) was found. With activator, inhibitor, siRNA and constitutively active or dominant-negative plasmids of PKB, we found that PKB increased the protein level of DNMT1 without coordinate mRNA change, which was specific rather than due to cell-cycle change. PKB enhanced DNMT1 protein stability independent of de novo synthesis of any protein, which was attributed to down-regulation of N-terminal-120-amino-acids-dependent DNMT1 degradation via ubiquitin-proteasome pathway. Gsk3beta inhibitor rescued the decrease of DNMT1 by PKB inhibition, suggesting that Gsk3beta mediated the stabilization of DNMT1 by PKB. Then role of PKB regulating DNMT1 was investigated. Inhibition of PKB caused observable DNA hypomethylation and chromatin decondensation and DNMT1 overexpression partially reversed cell growth inhibition by PKB inhibition. In conclusion, our results suggested that PKB enhanced DNMT1 stability and maintained DNA methylation and chromatin structure, which might contribute to cancer cell growth.