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This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made. AbstractThe androgen receptor (AR) pathway is critical for prostate cancer carcinogenesis and development; however, after 18-24 months of AR blocking therapy, patients invariably progress to castration-resistant prostate cancer (CRPC), which remains an urgent problem to be solved. Therefore, finding key molecules that interact with AR as novel strategies to treat prostate cancer and even CRPC is desperately needed. In the current study, we focused on the regulation of RNA-binding proteins (RBPs) associated with AR and determined that the mRNA and protein levels of AR were highly correlated with Musashi2 (MSI2) levels. MSI2 was upregulated in prostate cancer specimens and significantly correlated with advanced tumor grades. Downregulation of MSI2 in both androgen sensitive and insensitive prostate cancer cells inhibited tumor formation in vivo and decreased cell growth in vitro, which could be reversed by AR overexpression. Mechanistically, MSI2 directly bound to the 3′-untranslated region (UTR) of AR mRNA to increase its stability and, thus, enhanced its transcriptional activity. Our findings illustrate a previously unknown regulatory mechanism in prostate cancer cell proliferation regulated by the MSI2-AR axis and provide novel evidence towards a strategy against prostate cancer. K E Y W O R D Sandrogen receptor, mRNA stability, Musashi2, novel anti-androgen therapy, prostate cancer

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Bladder cancer (BC) is the most popular malignant urinary cancer, with the highest incidence and mortality of all genitourinary system tumors worldwide. To date, the molecular regulation of the metastasis of BC remains ill defined. Here, we examined the levels of matrix metallopeptidase 9 (MMP9) and nuclear β-catenin in the BC specimen. We used lithium chloride (LiCl) to inhibit cytosol β-catenin phosphorylation and degradation to increase nuclear β-catenin levels in BC cells. We used IWP-2 to enhance cytosol β-catenin phosphorylation and degradation to decrease nuclear β-catenin levels in BC cells. We examined MMP9 levels in these experimental settings by quantitative reverse transcription-PCR (RT-qPCR), Western blot, and ELISA. The cell invasiveness was evaluated by Transwell cell assay. We found significantly higher levels of MMP9 and nuclear β-catenin in human BC specimen with metastasis, compared to those without metastasis. Moreover, a strong correlation was detected between MMP9 and nuclear β-catenin. LiCl significantly increased nuclear β-catenin, resulting in MMP9 activation in BC cells. IWP-2 significantly decreased nuclear β-catenin, resulting in MMP9 inhibition in BC cells. MMP9 regulated cell invasiveness. Together, these data suggest that the WNT signaling pathway regulates metastasis of BC through activation of MMP9. Therapies targeting the WNT signaling pathway may be a promising treatment for BC.

The Fenton-like degradation of nalidixic acid was studied in this work. The effects of Fe(3+) concentration and initial H(2)O(2) concentration were investigated. Increasing the initial H(2)O(2) concentration enhances the degradation and mineralization efficiency for nalidixic acid, while Fe(3+) shows an optimal concentration of 0.25 mM. A complete removal of nalidixic acid and a TOC removal of 28 % were achieved in 60 min under a reaction condition of [Fe(3+)] =0.25 mM, [H(2)O(2)] =10 mM, T=35 °C, and pH=3. LC-MS analysis technique was used to analyze the possible degradation intermediates. The degradation pathways of nalidixic acid were proposed according to the identified intermediates and the electron density distribution of nalidixic acid. The Fenton-like degradation reaction of nalidixic acid mainly begins with the electrophilic attack of hydroxyl radical towards the C3 position which results in the ring-opening reaction; meanwhile, hydroxyl radical attacking to the branched alkyl groups of nalidixic acid leads to the oxidation at the branched alkyl groups.