U54 was used as an endogenous control to normalize miR-449a expression. promoter to drive gene expression. Either activation of autophagy by the inducer or overexpression of exogenous miR-449a decreases the expression of target gene LEF-1 and cyclin D1, which lead to decreased proliferation, colony formation, migration, and invasion of CRC cells. Autophagy-miR-449a-tartet genes mediated Mutant IDH1-IN-2 suppression of tumor formation was further confirmed in the xenograft mouse model. In conclusion, this study reveals a novel mechanism wherein autophagy utilizes miR-449a-LEF1-cyclin Mutant IDH1-IN-2 D1 axis to suppress CRC tumorigenesis. Our findings open a new avenue toward prognosis and treatment of CRC patients by manipulating autophagy-miR-449a axis. and luciferase activity in each lysate, which was used as the internal control. Immunohistochemistry IHC staining of paraffin section slides and tissue array with polyclonal anti-Beclin-1 (Abcam), anti-p62 (Medical and Biological Laboratories), anti-FoxO1 (Cell Signaling, C29H4), anti-Cyclin D1 (Abcam), or anti- LEF-1 (Lymphoid Enhancer Binding Factor 1) (Abcam, ab22884) were performed as previously described (18). Briefly, slides were labeled with biotin-linked secondary antibody followed by Streptavidin (Dako Cytomation, Carpinteria, USA) treatment for 10?min at room temperature. The slides were treated with AEC solution for 10?min and then counterstained with 10% hematoxylin (Muto Pure Chemicals, Tokyo, Japan) and mounted with glycerol gelatin (Sigma). MicroRNA Hybridization MicroRNA ISH was performed as described (14). Briefly, slides were hybridized with digoxigenin (DIG) LNA-modified-miR-449a using the IsHyb Hybridization kit (Biochain, Newark, NJ). Slides were incubated with anti-DIG-HRP antibody for 1 hour. MiR-449a signal was amplified by the TSA Plus DNP system (Perkin Elmer, Waltham, MA) and then incubated with anti-DNP-HRP for 1 hour. Slides were treated with an AEC solution and hematoxylin. Chromatin Immunoprecipitation Assay The cells were seeded onto 10?cm plates and treated with amiodarone (10 M; Sigma) for 24?h and the ChIP assay was conducted using a ChIP-IT High Sensitivity (HS) kit according to the manufacturers instructions (Active Motif, California, USA). Briefly, cells were crosslinked at 37C for 5?min using 1% formaldehyde. After sonication, the resulting chromatin was diluted 1:10 with ChIP dilution buffer and immunoprecipitated by anti-FoxO1 antibody (Cell Signaling, C29H4) or control IgG. The chromatin-antibody complex was incubated with salmon sperm DNA/Protein A Agarose-50% (Millipore Corp., Billerica, MA, USA) overnight at 4C with rotation. The DNA was eluted from the beads using ChIP elution buffer and purified by spin column. Colony Formation Assay The six-well plate was layered with 1ml of 0.6% basal agar Rabbit polyclonal to ATP5B dissolved in culture medium with serum. One hundred microliters of cell suspension was added to 0.9?ml of 0.4% agar dissolved in culture medium at 37C. The number of colonies formed was counted after 14 days under a light microscope. Mouse Xenograft Tumor Model Four-week-old female NOD/SCID mice were purchased from the Laboratory Animal Center, National Cheng Kung University (NCKU), College of Medicine, Tainan, Taiwan. The animals were maintained under sterile conditions in laminar flow rooms and provided with sterilized food and water. Animal welfare and the experimental studies complied with United States National Institutes of Health guidelines and the NCKU Laboratory Animal Care and Use Committee Guide for Care and Use of Laboratory Animals. Mutant IDH1-IN-2 This study was approved by the Institutional Animal Care and Use Committee (IACUC) of National Cheng Kung University (IACUC No: 100074). Eight mice were injected subcutaneously (s. c.) with SW480 cells (1107/100 l). After four days the tumors were formed, eight mice were randomly divided into two groups (Control: n=4, Mutant IDH1-IN-2 Amiodarone: n=4). The amiodarone group was injected intraperitoneally (i.p.) with amiodarone (30 mg/kg). The control group (N.C.) was injected with DMSO. This treatment continued at three-day intervals for a total of 27 days. Tumor volume was measured according to the formula: Volume (mm3) = (length width2)/2. The mice were sacrificed at day 27, and the tumors were collected. Statistical Analysis Data are presented as the mean SE values (error bars). Differences between the experimental and control groups were analyzed by two-tailed Students oncogene (19), starvation (Hanks balanced salt solution), or rapamycin to induce autophagic activity. Among five autophagy upregulated miRNAs, only miR-449a was ubiquitously upregulated, implying that miR-449a expression is usually specifically upregulated by autophagy ( Supplementary Table?2 ). Low expression of miR-449a in various cancers including prostate, gastric, liver, bladder, and lung cancers has been reported (20). We reveal that colorectal cancer cell line SW480 showed the second lowest level of miR-449a among seven analyzed cancer cell lines ( Supplementary Physique?1 ). Similarly, Sun et al, reported.
