0, CapitalBio). Signal intensities for each spot were calculated by subtracting local background from total intensities. Raw data were normalized and analyzed using the Significance Analysis of Microarrays (SAM, version 2.1, Stanford University, CA, USA) software [25]. The raw data was Log2 transformed and median centered by arrays and genes using the adjust data function of CLUSTER 3.0 software for cluster analysis [26]. Stem-loop qRT-PCR for miRNAs All miRNA-specific primers were designed find more according to miRNA sequences. The universally expressed U6 was used as an internal control. Reverse transcriptase reactions contained 2.5 ng/μL purified total RNA, 50 nM stem-loop reverse

transcription (RT) primer, 1 × RT buffer, 0.25 mM of each of dNTPs, 3.33 U/ml MultiScribe reverse transcriptase, 0.25 U/ml RNase inhibitor. The 7.5 μL reactions were incubated in an MJ Research PTC-225 Thermocycler for 30 min at 16°C, 30 min at 42°C, 5 min at 85°C, and then held at 4°C. All reverse transcriptase reactions were run in duplicate. Stem-loop qRT-PCR was performed as described in published references [27]. The 10 μl PCR reaction contained 0.67 μl RT product, 1 × PCR Master Mix, 1.5 μM forward primer, and 0.7 μM reverse primer. The reactions were incubated

at 95°C for 10 min, followed by 40 cycles of 95°C for 15 s and 60°C for 1 min. All reactions were run in triplicate. Melting curves were performed using Dissociation Curves software (Funglyn) to ensure only a single product was amplified, and PARP inhibitor the specificity of samples was confirmed by running on a 3% agarose gel. All reagents from MBI Company (MBI Fermentas, Maryland, USA) were used following the manufacturer’s protocols. Results The effect of DMBA-induced oral carcinogenesis Two animals died during the experimental period (one each from Groups A and B). Histologically, all samples

from Group C appeared normal, with a thin epithelium devoid of rete ridges (Figure 1A~C). Five animals from Group A and seven animals from Group B developed SCC (Figure 1D~F). The tumor diameters ranged from 1.5 mm to 15 mm in both groups, with an average diameter of 5 ± 1.69 mm and 8.7 ± 2.55 mm for STAT inhibitor Group A and B, respectively (Table 1). Most of the squamous cell carcinomas were classified as well-differentiated or moderately differentiated. Figure 1 DMBA-induced oral carcinogenesis in the hamster cheek pouch (H&E staining). (A~C) Normal epithelium; (D) SCC; (E) Papillary SCC; (F) SCC. miRNA microarray analysis RNA gel electrophoresis demonstrated that the quality of the RNA was good. SAM was performed to identify differences in miRNA expression between cancerous and normal samples. SAM calculated a score for each gene on the basis of the change in expression relative to the S.D. of all measurements. The SAM data indicated that 5 miRNA genes were significantly overexpressed and that 12 miRNA genes were significantly underexpressed in cancer samples, with fold changes>2.