BACKGROUND & AIMS Variants in genes that regulate autophagy have been associated with Crohn’s disease (CD). Defects in autophagy-mediated removal of pathogenic microbes could contribute to pathogenesis of CD. We investigated the role of the micro-RNAs (miRs) MIR106B and MIR93 in induction of autophagy and bacterial clearance in human cell lines, and the correlation between MIR106B and autophagy-related gene 16L1 (ATG16L1) expression in tissues from patients with CD. METHODS We studied the ability of MIR106B and MIR93 to regulate ATG transcripts in human cancer cell lines (HCT116, SW480, HeLa, and U2OS) using luciferase report assays and bioinformatics analyses; MIR106B and MIR93 mimics and antagonists were transfected into cells to modify levels of miRs. Cells were infected with LF82, a CD-associated adherent-invasive strain of Escherichia coli, and monitored by confocal microscopy and for colony-forming units. Colon tissues from 41 healthy individuals (controls), 22 with active CD, 16 with inactive CD, and 7 with chronic inflammation were assessed for levels of MIR106B and ATG16L1 by in situ hybridization and immunohistochemistry. RESULTS Silencing Dicer 1, an essential processor of miRs, increased levels of ATG protein and formation of autophagosomes in cells, indicating that miRs regulate autophagy. Luciferase reporter assays indicated that MIR106B and MIR93 targeted ATG16L1 mRNA. MIR106B and MIR93 reduced levels of ATG16L1 and autophagy; these increased following expression of ectopic ATG16L1. In contrast, MIR106B and MIR93 antagonists increased formation of autophagosomes. Levels of MIR106B were increased in intestinal epithelia from patients with active CD, whereas levels of ATG16L1 were reduced, compared with controls. Levels of CMYC were also increased in intestinal epithelia of patients with active CD, compared with controls. These alterations could impair removal of CD-associated bacteria by autophagy. CONCLUSIONS In human cell lines, MIR106B and MIR93 reduce levels of ATG16L1 and autophagy, and prevent autophagy-dependent eradication of intracellular bacteria. This process also appears to be altered in colon tissues from patients with active CD.

Piperlongumine (PL), a natural product isolated from the plant species Piper longum L., can selectively induce apoptotic cell death in cancer cells by targeting the stress response to reactive oxygen species (ROS). Here we show that PL induces cell death in the presence of benzyloxycarbonylvalyl-alanyl-aspartic acid (O-methyl)-fluoro-methylketone (zVAD-fmk), a pan-apoptotic inhibitor, and in the presence of necrostatin-1, a necrotic inhibitor. Instead PL-induced cell death can be suppressed by 3-methyladenine, an autophagy inhibitor, and substantially attenuated in cells lacking the autophagy-related 5 (Atg5) gene. We further show that PL enhances autophagy activity without blocking autophagy flux. Application of N-acetyl-cysteine, an antioxidant, markedly reduces PL-induced autophagy and cell death, suggesting an essential role for intracellular ROS in PL-induced autophagy. Furthermore, PL stimulates the activation of p38 protein kinase through ROS-induced stress response and p38 signaling is necessary for the action of PL as SB203580, a p38 inhibitor, or dominant-negative p38 can effectively reduce PL-mediated autophagy. Thus, we have characterized a new mechanism for PL-induced cell death through the ROS-p38 pathway. Our findings support the therapeutic potential of PL by triggering autophagic cell death.

LESS(sc)-VL is a safe and effective minimally invasive surgical alternative for varicocelectomy. Compared with CTL-VL, LESS(sc)-VL may decrease postoperative pain and hide the surgical incision better within the umbilicus.

Castration-resistant prostate cancer (CRPC) is difficult to treat in current clinical practice. Hypoxia is an important feature of the CRPC microenvironment and is closely associated with the progress of CRPC invasion. However, no research has been performed on the immune escape of CRPC from NK cells. The present study focused on this subject. Firstly, when the CRPC cell lines C4-2 and CWR22Rv1 were induced by hypoxia, the expression of the UL16 binding protein (ULBP) ligand family of natural killer (NK) group 2D (NKG2D; ULBP-1, ULBP-2 and ULBP-3) and MHC class I chain-related proteins A and B (MICA/MICB) decreased. NKG2D is the main activating receptor of NK cells. Tumor cells were then co-cultured with NK cells to conduct NK cell-mediated cytotoxicity experiments, which revealed the decreased immune cytolytic activity of NK cells on hypoxia-induced CRPC cells. In exploring the mechanism behind this observation, an increase in programmed death-ligand 1 (PD-L1) expression in CRPC cells induced by hypoxia was observed, while the addition of PD-L1 antibody effectively reversed the expression of NKG2D ligand and enhanced the cytotoxic effect of NK cells on CRPC cells. In the process of exploring the upstream regulatory factors of PD-L1, inhibition of the Janus kinase (JAK)1,2/signal transducer and activator of transcription 3 (Stat3) signaling pathway decreased the expression of PD-L1 in CRPC cells. Finally, it was observed that combined inhibition of JAK1,2/PD-L1 or Stat3/PD-L1 was more effective than inhibition of a single pathway in enhancing the immune cytolytic activity of NK cells. Taking these results together, it is thought that combined inhibition of the JAK1,2/PD-L1 and Stat3/PD-L1 signaling pathways may enhance the immune cytolytic activity of NK cells toward hypoxia-induced CRPC cells, which is expected to provide novel ideas and targets for the immunotherapy of CRPC.

Background: High levels of the post-translational modification O-GlcNAcylation (O-GlcNAc) are found in multiple cancers, including bladder cancer. Autophagy, which can be induced by stress from post-translational modifications, plays a critical role in maintaining cellular homeostasis and regulating tumorigenesis. The impact of O-GlcNAcylation on autophagy in bladder cancer remains unclear. Here, we evaluate the change in autophagic activity in response to O-GlcNAcylation and explore the potential mechanisms. Methods: O-GlcNAcylation levels in bladder cancer cells were altered through pharmacological or genetic manipulations: treating with 6-diazo-5-oxo-norleucine (DON) or thiamet-G (TG) or up-and downregulation of O-GlcNAc transferase (OGT) or O-GlcNAcase (OGA). Autophagy was determined using fluorescence microscopy and western blotting. Co-immunoprecipitation (Co-IP) assays were performed to evaluate whether the autophagy regulator AMP-activated protein kinase (AMPK) was O-GlcNAc modified. Results: Cellular autophagic flux was strikingly enhanced as a result of O-GlcNAcylation suppression, whereas it decreased at high O-GlcNAcylation levels. Phosphorylation of AMPK increased after the suppression of O-GlcNAcylation. We found that O-GlcNAcylation of AMPK suppressed the activity of this regulator, thereby inhibiting ULK1 activity and autophagy. Conclusion: We characterized a new function of O-GlcNAcylation in the suppression of autophagy via regulation of AMPK.