1.2 Cell culture and treatment
Human glioblastoma cell lines T98G and rat glioma C6 cells were obtained from American-type culture collection (ATCC, Manassas, VA, USA). Both cells were grown in RPMI 1640 containing 1% penicillin-streptomycin and 10% fetal bovine serum (GIBCO/BRL, NY, USA). Cultures were maintained in a humidified atmosphere with 5% CO2 at 37°C. Cells were treated with different concentrations (0.0, 0.5, 1.0, 1.5, 2.0, 2.5) µM of HDAC inhibitor (MGCD0103) that was purchased from Selleckchem.com (Selleck Chemicals, Houston, TX, USA). The drug was dissolved in dimethyl sulfoxide (DMSO) to get the final concentration (5.0mM) like a sock solution. The stock solution was stored at -20°C.
2.2 A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) cell proliferation assay
The MTT assay is the best method to measure the viability of cells and the cytotoxic effects of drugs. Cellular metabolic activity of C6 and T98G was measured depending on the manufacturer’s instructions (ATCC, Manassas, VA, USA). Briefly, 0.5 x 104 cells/well were seeded into 96-well plates containing growth medium RPM1 with supplements (10% PBS and 1% penicillin and streptomycin) and incubated with 5% CO2 at 37°C. After the growth cells got 70% confluence, the current medium was replaced with a new medium containing varied concentrations (0, 0.5, 1.0, 1.5, 2.0, 2.5) µM of MODC0103 for 48 h. Then, the 10µL MTT solution (ATCC, VA, USA) was put in each well and grown for 4h. Detergent reagent (ATCC, Manassas, AV, USA) was applied to each well in quantities of 100 mL to dissolve MTT formazan crystals., a wavelength absorbance was measured using a microplate reader (Bio-Rad, Hercules, CA, USA) at 570 nm, absorbance was recorded, and at 690 nm absorbance of the background was subtracted. All experiments were in triplicate.
3.2 In vitro differentiation cancer cells assay
The different concentrations of MGCD0103 were used to identify the ability of mocetinostat to induce astrocytic differentiation in glioblastoma cell lines C6 and T98G. Using 6 well plates, cells were cultivated in growth medium RPMI-1406 with 10% FBS and 1% Penicillin/Streptomycin. The cultures were placed in the incubation with 5.0% CO2 and 37⁰C for 24h. After the culture medium was removed, the cells cultured in the medium were supplemented with different concentrations of MGCD0103. The cells were placed in the incubation conditions of 5% CO2 at 37⁰C for 48h. After treating the cells with drugs, the culture medium was aspirated and washed twice with BPS. After that, the cells were fixed and stained using a Kwik-Diff™ kit according to the protocol of the manufacturer (Thermo-Scientific, MO, USA). The samples were examined under light microscopy to watch the differentiation features of cells.
4.2 Detection of Morphological characteristics using Apoptosis assay
The morphological feature of apoptosis cells was achieved by right staining. Both cell lines C6 and T98G at density 0.5x104 were cultured in 6 wells containing RPMI-1460 supplement with 10% FBS and 1% Penicillin /Streptomycin, then incubated in the condition of 5% CO2 at 37⁰C for 48 h. After removing the old medium, 2mL of the new medium supplement with Each well received different doses of MGCD0103 before being incubated for 48 hours. The supernatant was discarded and washed twice with PBS. Then, the cells were fixed and stained utilizing a Kwik-Diff™ staining kit following instructions provided by the manufacturer (Thermo-Scientific, St. Louis, MO, USA). The morphological features of apoptosis cells were imaged under a light microscope (Olympus, Pittsburgh, PA, USA). Image J was used to measure the percentage of apoptotic cells. The apoptosis rate was measured after counting 300 cells from each treatment.
5.2 Identification of biochemical apoptotic populations using flow cytometry and Annexin FITC/PI double staining.
a Fluorescein Isothiocyanate (FITC)-Annexin V and propidium iodide (PI) staining Apoptosis were examined to detect the Biochemical characteristics of apoptotic cells using Apoptosis Detection kit (BD Biosciences) according to the manufacturer’s instructions. Both cell lines (C6 and T98g ) were cultivated independently in 6 wells and subjected to various concentrations of MGCD0103 (0.0, 0.5, 1.0, 1.5, 2.0, 2.5) µM for 48 h. Once the cells were harvested and centrifuged at 2500x for 5 min, they were washed cold BPS twice and resuspended in 100µl 1x binding buffer (0.1 M HEPES, NaOH, PH 7.4,1.4 NaCl, and 25Mm Cacl2). The cells were transferred to a 5mL polystyrene culture tube and stained with 5µl of Annexin-V-FITC and 5µL of PI. All tubes were incubated for 15 min at darkroom temperature for the staining of cells. Then, 400µL of binding buffer was added to each tube and analyzed by flow cytometry using an Epics XL-MCL Flow Cytometry (Beckman Coulter, Fullerton, CA, USA). Three duplicates of each experiment were carried out. The cell populations were identified on the plot as a red dot, with viable cells (FITC−/PI−) appearing in the left lower quadrant (Q3), early apoptotic cells (FITC+/PI−) were displayed in the right lower quadrant (Q4), and necrotic and late apoptotic cells (FITC+/PI+) were presented in the right upper quadrant (Q2). The necrotic cells were seen in the left upper quadrant (Q1).
6.2 Scratch wounding migration assay
Determining the ability of MGCD0103 to suppress the motility of cells was evaluated by migration assay. Both 2x105 T98G and C6 cells were grown in 6 well after the cells approximately reached a confluence rate of 90%. A 200-L sterile plastic pipette tip was used to gently scrape the cell monolayers in the center of the well. To eliminate the floating and debris cells, the gap was twice rinsed with a growing media. The old medium was removed from each well and a fresh medium containing various concentrations of MGCD0103 was added to each well and incubated with 5% CO2 at 37⁰C for 24 h. Then the medium was discarded and fixed with 70% alcohol. Inverted light microscopy with a camera (BioTeck Instruments, Inc, VT, USA) was used to examine the cells' movement into the wound area. and the distance between the scratches was analyzed by Image J. To calculate the percentage of wound closure, the formula below was used: Closure of a wound is equal to [1-(wound area at Tt/wound area at T0) 100. The wound's creation time is T0, and the time since it was caused is Tt. Three times the tests were run.
7.2 Matrigel Invasion assay
Briefly, C6 and T98G cells were cultivated in a 24-transwell chamber supplied with 8.0µm pore size polycarbonate filters (Corning Life Science, Corning, NY, USA) covered in 200 µL Matrigel (Corning Life Science, Corning, NY, USA) at a final concentration 1.0 mg/mL, which was allowed to solidify at 37⁰C for 4h. 1x105 cells were suspended with 100 µL of growth medium-free serum and placed into the upper chamber of the transwell. In the lower chamber of the transwell plate, 600 µL of RPMI-1640 growth medium containing 10% FBS and 1% penicillin + streptomycin supplement with various concentrations of MGCD0103 was added and then incubated for 2 days in 5% CO2 at 37⁰C for 48h. At the end of incubation, the cells had invaded the Matrigel and attached to the lower surface of the filter. Consequently, the medium from the upper chamber was discarded, and the cell migration was fixed by alcohol 70% for 1 min. Once the alcohol was removed, the cells were stained with 0.1% crystal violate for 15 min. Then, the cells were washed with double distilled water. By swabbing cotton, the non-migration cells were eliminated. Light microscopy was used to examine the cells' passage through the Matrigel and onto the lower surface of the filter. (Leica Microsystems, Inc, USA) and the percentage of cells’ migration was quantified using the Image J program (National Institutes of Health, Bethesda, MD, USA).
8.2 Invitro network angiogenesis assay
To study the effect of various concentrations of MGCD0103 on the inhibition of angiogenesis, we achieved network angiogenesis in vitro by using the Co-Culture Tube Formation Assay kit (Ibidi, Gräfelfing, Germany) as described in the company’s instructions. The Matrigel (10 µL) was placed in a 15-well chamber slide and incubated with 5% CO2 at 37⁰C to solidify for 1h. Each of the C6 and T98G cells at a density of 2.5 x104 was separately mixed with 104 human mammary epithelial (HME) cells as co-culture, then they were added to each tube containing 50 µL RPMI and incubated for 6 h to network formation. After the culture medium was aspirated off the Matrigel surface, 50 µL of growth medium supplement of different concentrations was added to each well-containing network. The chamber slide was incubated for 24 h in 5% CO2 and 37C⁰. After that, the culture medium was expelled. Cells were fixed with methanol and the image was observed by light microscopy (Leica Microsystems, Inc, USA). The tube information was counted by Image J software (National Institutes of Health, Bethesda, MD, USA).
9.2 Proteins extraction by SDS-PAGE assay
Protein extracted from both cell lines C6 and T98G were cultured in (60mm) of growth medium RPIM with 10% FBS, 1% Penicillin /Streptomycin, and incubated in 5% CO2 at 37⁰C. After the cells cultured reached confluence, the culture medium was removed and replaced with a culture medium supplement with various concentrations of MGCD0103 for 48 h at 37⁰C. Once the treatment period was finished, the pellet from the cells was scraped and washed twice with ice-cold PBS. The cells were centrifuged at 2500rpm for 5 min and discarded in their supernatant. After that, the pellet cells were lysate with 250µL of cold RIPA buffer (25mM Tris•HCl pH 7.6, 150mM NaCl, 1% NP-40, 1% sodium deoxycholate, 0.1% SDS) (Thermofisher, IL, USA) and kept on ice for 30 minutes. The test tubes were shaken five times by vortex. After being lysate, they were centrifuged at 13,000rpm for 15 min at 4⁰C. The supernatant-containing proteins were then transferred to tubes and kept at -20⁰C for further analysis.
10.2 Western blot
The protein concertation was determined with BCA and Coomassie blue. The equal amounts of protein from each sample mixed with loading buffer and mixtures were boiled at 100⁰C for 5 min. The samples were separated by electrophoresis on 4–20% of SDS-PAGE gel for 1.5 h. After electrophoresis, the blot was transferred from the gel into the PVDF membrane (Thermofisher, IL, USA). Block with 5% nonfat dry milk in PBS-Tween 20 (0.05%, v/v) for 1 hour at room temperature. Following the membrane were incubated with the primary antibody overnight. The next day, the membrane was washed five times with PBS. Subsequently, a Suitable horseradish peroxidase-conjugated secondary antibody was incubated with the membranes. that was added to the membrane for 1h at room temperature. After washing with (PBST) five times at room temperature, the membrane was incubated with enhanced electro chemiluminescent for 5 min the results were acquired by X-ray film.
11.2 Antibody
The antibody anti-B-actin (#4967) (Cell Singling, USA) was purchased from Cell Signaling (Cell Signaling, MA, USA). The other primary antibodies used in this study were Bax(sc-4780), Bcl2(sc-7382), Bid(sc-6539) HDAC1, (sc-7872), Caspase 3(sc-7148), MMP9 (sc-13520), MMP 2(sc-1359), GAFP(sc-6170), pRB( sc-12901(), Rb(sc-15)N-Myc(sc-42), Id2 (sc-489), VEGF (sc-7269), EGFR2 (sc-271847), P-BAD( sc-133356), pAKT-1(sc-514032) were purchased from Santacruz Biotechnology (Santa Cruz, CA, USA) PI3K ( GTX50858) was purchase from Gene Tex, USA, AKT( 6744) was purchased Bio vision, USA). Horseradish peroxidase-conjugated secondary anti-rabbit was purchased from Santa Cruz Biotechnology (Santa Cruz, CA), and anti-mouse (Santa Cruz, CA, USA)
12.2 Statically analysis
Data were represented as the mean standard error (± SEM). All experiments were repeated three times. In all experiments, results were analyzed using GraphPad Prism software (one-way ANOVA). Statically differences between groups were considered relevant at P > 0.05. All measurements were compared with the control. P*<0.05, P**<0.01,p#<0.001