LncRNAs have been shown to play essential roles in bladder cancer (BC) progress.Our microarrays of clinical samples firstly screened that lncRNA muscleblind-like 1 antisense RNA 1 (MBNL1-AS1) was poorly expressed in BC tissues. However, its biological function in BC remains not well understood. Here we examined the clinical correlations with MBNL1-AS1 in BC patients. Then, 5673 and T24 cell lines were employed to investigate the role of MBNL1-AS1 in the proliferation and apoptosis of BC cells in vitro and in vivo. Furthermore, miR-135a-5p (miR-135a)/PHLPP2/FOXO1 axis was focused to explore its regulatory mechanism in BC.The results showed that MBNL1-AS1 was significantly downregulated in bladder tumor tissues, and associated with BC progression. In vitro, MBNL1-AS1 knockdown increased the number of viable cells and bromodeoxyuridine-positive cells, accelerated cell cycle, and dysregulated proliferative regulators (Ki67, p21, p27, and Cyclin D1) in BC cells. The apoptotic cells and the cleavages of caspase-3/9 were reduced in MBNL1-AS1-silenced BC cells. Overexpression of MBNL1-AS1 had opposite effects on BC cell proliferation and apoptosis. Moreover miR-135a was demonstrated to interact with MBNL1-AS1, and inhibiting miR-135a reversed the effects of shMBNL1-AS1 on BC cells. The downstream effectors (PHLPP2 and FOXO1) were positively regulated by MBNL1-AS1, but negatively regulated by miR-135a. Similar results were also observed in xenograft tumors. In conclusion, this study firstly suggests that MBNL1-AS1 acts as a tumor suppressor of BC by targeting miR-135a/PHLPP2/FOXO1 axis, providing a novel insight for BC diagnosis and treatment. K E Y W O R D S bladder cancer, FOXO1, MBNL1-AS1, miR-135a-5p, PHLPP2 | 725 WEI Et al.

Background/Aims: The TLR/MyD88/NF-κB signaling pathway has been successfully used to treat renal interstitial fibrosis (RIF). However, the exact therapeutic mechanism is still unknown. Here, we assessed the therapeutic efficacy of TJ-M2010-2, a small molecular compound that inhibits MyD88 homodimerization, in RIF induced by ischemia reperfusion injury (IRI). Methods: In vivo, RIF was induced in mice by IRI, and the mice were prophylactically treated with TJ-M2010-2. In vitro, HK-2 cells were incubated with TGF-β1 to induce EMT, and the cells were pretreated with TJ-M2010-2. Results: We found that, compared with the IRI group, the TJ-M2010-2 group showed marked attenuation of RIF and renal function injury; decreased expression of TGF-β1, α-SMA, vimentin, MMP2 and MMP9; and increased E-cadherin expression. Furthermore, TGF-β1-induced EMT was blocked by TJ-M2010-2 in HK-2 cells, as evidenced by blocked morphologic transformation, restored E-cadherin expression and inhibited α-SMA expression. In addition, compared to the TGF-β1 group, the TJ-M2010-2 group showed profound inhibition of the expression of TRAF6, p65 and Snail and upregulation of the expression of IκBα. Conclusion: This MyD88 inhibitor may be a potential therapeutic agent to ameliorate RIF.

In this study, we found miR-362-5p was upregulated in bladder cancer tissues and we predicted that QKI is potential a target of miR-362-5p and MBNL1-AS1 might be able to directly target to miR-362-5p. We attempted to evaluate whether miR-362-5p could play its roles in bladder cancer through regulating QKI (quaking) and whether the expression and function of miR-362-5p could be mediated by lncRNA MBNL1-AS1. We performed the gain-and loss-function experiments to explore the association between miR-362-5p expression and bladder cancer proliferation. In vivo, the nude mice were injected with miR-362-5p knockdown SW780 cells to assess the effects of miR-362-5p on tumor growth. The results showed upregulation of miR-362-5p promoted cell proliferation of bladder cancer cells. MBNL1-AS1 and QKI could directly bind with miR-362-5p, and knockdown of MBNL1-AS1 or QKI could abrogate the regulatory effects of miR-362-5p on bladder cancer cell proliferation. Furthermore, downregulation of miR-362-5p inhibited bladder tumor growth and increased QKI expression. Our data unveiled that miR-362-5p may play an oncogenic role in bladder cancer through QKI and MBNL1-AS1 might function as a sponge to mediate the miR-362-5p expression and function.

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