Clinical samples. Tissue samples were obtained from patients who underwent radical prostatectomy or transurethral resection of the prostate at the Tianjin Medical University Hospital (Tianjin, China) and inspected by a certified pathologist for Gleason grading.
Cell culture. The PCa cell line LNCaP, C4-2 ,22RV1 and PC3 were obtained from ATCC. Cells were maintained in RPMI 1640 medium supplemented with 10% FBS, 1% penicillin/streptomycin, and 1% glutamine. DHT was obtained from Amersham (Braunschweig, Germany).
siRNA. Validated siRNAs were from GenePharma (ShangHai, China). Transfections were performed using the lipo2000 (Thermo Fisher) according to the manufacturer's instructions.
Co-Immunoprecipitation and Western blotting.
LNCaP and C4-2 cells were harvested and lysed in lysis buffer (150 mM KCl,75 mM Hepes, pH 7.5, 1.5 mM EGTA, 1.5 mM MgCl2, 10% glycerol, and 0.075% NP-40 supplemented with protease inhibitor cocktail[Roche,USA]. Extract proteins were precleared using a mixture of protein A–Sepharose (CL-4B; GE Healthcare) and antibody for overnight hr at 4˚C. Immunoprecipitates were washed with lysis buffer and resuspended in sample buffer, boiled and analyzed by SDS-PAGE. Individual samples (40 µg of protein) were separated on 8% SDS polyacrylamide gel and transferred to PVDF membranes (Millipore, Billerica, MA). Membranes were blocked in a PBS-Tween 20 solution with 5% fat-free milk for 1 h at room temperature, and then the membranes were incubated with appropriate dilutions of specific primary AR or TNIK antibodies overnight at 4 °C. After washing, the blots were incubated with HRP conjugated anti-rabbit or anti-mouse IgG for 1 h. The blots were developed in ECL mixture(Vector Laboratories, Burlingame, CA) and visualized by Imager.
Chromatin Immunoprecipitation
LNCaP cells were grown in 1640 (Invitrogen) supplemented with 10% charcoal-stripped FBS (CSF, HyClone, USA) for 12 h. DNA cross-linking was performed by adding 1% formaldehyde into the cell cultures at room temperature for 10 min, and glycine was then added (0.125 M final concentration) for 5 min to stop the cross-linking reaction. Cells were lysed with a lysis buffer with protease inhibitors and sonicated to shear genomic DNA to lengths between 200 and 1000 bp. One-tenth of the cell lysate was used for input control, and the rest was used for immunoprecipitation using AR or H3K27me3 antibody. After collecting the immunoprecipitates using protein G-agarose columns, protein-DNA complexes were eluted and heated at 65 °C to reverse the cross-linking. After digestion with proteinase K, DNA fragments were purified using spin columns and analyzed using PCR for 35 cycles in a sequence of 94 °C for 30 s, 55 °C for 30 s, and 72 °C for 1 min. Specific primer sets were designed to amplify a target sequence within the human TNIK promoter as table 2. PCR products were electrophoresed in a 1.5% agarose gel with ethidium bromide and visualized under ultraviolet light.
Whole-transcript expression array and microarray image processing
One µg/µl of total RNA was used as a starting material for making total RNA/Poly-A RNA controls, and was mixed with a GeneChip®Eukaryotic Poly-A Control Kit (Affymetrix, Inc., CA, USA). The majority of the rRNA was removed from the total RNA samples prior to target labeling, so as to increase sensitivity by RiboMinusTM Human Transcriptome Isolation Kit (Invitrogen, CA, USA); cDNA was synthesized using the GeneChip® WT Sense Target Labeling and Control Reagents Kit, as per the manufacturer’s instructions (Affymetrix, Inc., CA, USA). The sense cDNA was then fragmented by UDG (uracil DNA glycosylase) and APE 1 (apurinic/apyrimidinic endonuclease 1), and biotin-labeled with TdT (terminal deoxynucleotidyl transferase) using a GeneChip® WT Terminal Labeling Kit. (Affymetrix, Inc., CA, USA). After the biotin-labeled sense target DNA was prepared, the sample was ready to hybridize to gene chip (The GeneChip® Human Exon 1.0 ST array). Hybridization was performed using 5 µg of biotinylated target, which was incubated with a GeneChip® Hybridization, Wash and Stain Kit and a GeneChip® Fluidics Station 450 (Affymetrix, Inc., CA, USA). The arrays were scanned using a GeneChip® Scanner 3000 7G (Affymetrix, Inc., CA, USA). Raw data were extracted from the scanned images and analyzed with GeneSpring GX software version 11.5 (Agilent Technologies, CA, USA).
Luciferase assays.
For the dual luciferase assay, C4-2 cells were plated in triplicate into 12-well plates and cotransfected with 1 µg of the reporter construct and 15 pmol of β-catenin luciferase together with TNIK wt or D171A of plasmids by using transfection reagent (Roche). Transfected cells were cultured and 24 h later, the supernatants were collected for luciferase assay using Dual Luminescence assay kit (GeneCopoeia MD) according to the manufacturer's instructions.
Animal studies
Four-week-old male Babl/c mice (HFK Bio-Technology Co. Ltd, Beijing) were injected subcutaneously with 2 × 106 C4-2 cells suspended in 0.1 mL of Matrigel (BD Biosciences), and were implanted subcutaneously into the dorsal flank on both sides of the mice. Once the tumors reached an stage about 100 mm3, mice administered daily by oral gavage either with vehicle (10% DMSO in PBS) or NCB-0846 (80 mg/kg of body weight) for 10 days (n = 4 mice for each treatment). Tumor volume was recorded by digital caliper san estimate using the formula LW2/2, where L = length of tumor and W = width. At the end of the studies mice were killed and tumors extracted and weighed. All procedures involving mice were approved by the University Committee on Use and Care of Animals at the Tianjin Medical University and conform to all regulatory standards. Mice permit number is SYXK(Jin)2019-0004.
Immunohistochemistry.
Tissue sections were de-waxed in xylene and rehydrated in graded alcohol. Antigen retrieval was done under pressure for 5 min in citrate buffer (pH adjusted to 6.0). Endogenous peroxidase was blocked in 0.3% hydrogen peroxide for 10 min and blocked using 1.5% horse serum. Incubation with primary antibody was done in a humidified chamber overnight at 4 °C (anti-TNIK, 1:100 from sigma; anti-Ser675 1:100 from Cell Signaling Technology; Ki67 1:100 from Abcom). After applying Poly-HRP anti-rabbit IgG (30 min), secondary antibody detection was performed using the Ultraview DAB detection kit (Zhongshan Co, China). In the case of TNIK, Ser675 and Ki67, only nuclear staining was considered as positive and was scored. All immunostained sections were evaluated under Zeiss microscope (× 200). At least 10 high power fields around each of the malignant glands were evaluated and scored.