The immunoreactive protein bands were developed using the Enhanced Chemiluminescence (ECL Plus) selleck system (Amersham Bioscience, UK). Reverse transcription-polymerase chain reaction Cells treated with risedronate (0, 0.1, 1, 10 μM) for 48 h and washed with ice-cold 1× phosphate buffered saline
(PBS) twice. Total RNA was extracted using TRIzol Reagent (Invitrogen, USA), according to the manufacturer’s instructions. RNA (1 μg) was reverse-transcribed using the Superscript™ First-Strand Synthesis System for RT-PCR (Invitrogen, San Diego) at 37°C. The following primers were used to determine target gene levels. β-actin (sense 5′-CTGGAGCATGCCCGTATTTA-3′ and anti-sense 5′-TTTGGTCTTGCCACTTTTCC-3′), MMP-2 (sense 5′-CTCAGATCCGTGGTGAGATCT-3′ and anti-sense 5′-CTTTGGTTCTCCAGCTTCAGG-3′) and MMP-9 (sense 5′-AAGTGGCACCACCACAACAT-3′ and anti-sense 5′-TTTCCCATCAGCATTGCCGT-3′). All primers were checked against the GeneBank Database to ensure no cross-reactivity with other known human DNA sequences. PCR cycles were performed using the following sequence: 94°C for 5 min, then 30 cycles of denaturation at 94°C for 1 minute, annealing at 60°C (for MMP-2) or 58°C (for MMP-9) for 1 minute, and polymerization at 72°C for 1 minute), and followed by 72°C for 7 minutes. RT-PCR products were visualized
on 1.2% agarose gels electrophoresed in 0.5 TAE MMP inhibitor buffer containing 0.5 μg/ml ethidium bromide. Statistical analysis Band Intensities were quantified using Multi Gauge V3.0 and Scion Image software. Results are expressed as means ± standard deviations. Statistical significance
was accepted for p values of < 0.05 by the Kruskal-Wallis check details Test and Mann-Whitney U test, and all statistical analyses were reviewed independently by a statistician. Results The antiproliferative effects of risedronate on SaOS-2 and U2OS cells MTT assays were used to determine the effects of risedronate on osteosarcoma cell growth. Risedronate treatment at 0 to 10 μM for 48-hours did not significantly inhibit the growth of either cell-line (Fig. 1), demonstrating that it has no significant effect on SaOS-2 or U2OS survival at a concentration of 10 μM. Thus, we performed all subsequent experiments using risedronate concentrations between 0 and 10 μM Figure 1 Risedronate Thiamet G at concentrations up to 10 μM had no cytotoxic effect on either SaOS-2 or U2OS cells. Both cell lines in serum-free MEM were treated or not with the indicated concentrations of risedronate and then incubated for 48 h before doing MTT assay for cell growth quantification. The bar graph shows the absorbance (expressed as percentages of controls) measured at 570 nm on an ELISA reader (n = 3 independent experiments; mean ± standard deviation is shown). Risedronate suppressed the invasive capacities of SaOS-2 and U2OS cells We carried out Matrigel invasion assays after treating SaOS-2 and U2OS cells with risedronate.