|Application:||Gene expression microarray analysis|
|Number of samples:||36|
|Release date:||Dec 31 2011|
|Last update date:||Mar 22 2012|
|Dataset link||Gene expression profile of murine cutaneous melanoma after systemic treatment with tumor necrosis factor (TNF) associated or not with melphalan (MEL).|
We used amplified RNA (aRNA) from 18 tumor samples (Control – 5 samples; Mel – 4 samples; Tnfa – 4 samples; and Mel+Tnfa – 5 samples). For replica hybridization with dye swap, aRNA from the tumors and from a pool composed of equal amounts of RNA extracted from the K1735M2, M2R, B16F10, and B16F1 melanoma cells were labeled with Alexa555 or Alexa647. Labeled aRNA samples were hybridized against a glass platform containing 16,128 immobilized sense oligonucleotides (Fox Chase Cancer Center, USA) corresponding to murine genes. Slides were pre-hybridized at 42ºC for approximately 6 hours in a solution containing Denhardt’s 5X (Ficoll 400 0.05g/mL, poli-vynil-pyrrolidone 0.05g/mL, bovine serum albumin 0.05g/mL), SSC (sodium saline citrate) 5X, 0.2% SDS (Sigma), and 1% BSA. For hybridization, we used a mix of 3.5µg of each labeled sample aRNA and reference aRNA. The hybridization solution contained Denhardt’s 5X, formamide 25% (Sigma), SSC 5X, SDS 0.1%, salmon sperm DNA 0.1mg/mL (GE Healthcare), Poly-A 0.1mg/mL (GE Healthcare), and Cot-1 0.1mg/mL (GE Healthcare), to a final volume of 100µL. Hybridizations were carried out on a Gene Tac hybridization station (Genomic Solutions) at 42ºC for about 16h. The slides were removed from the hybridization cassettes directly to a recipient containing a washing solution (SSC 2X, SDS 0.1%) at 42ºC, put in a slide rack, transferred to another recipient containing fresh solution, and washed under constant agitation at 42ºC for 5 min. After that, they were washed twice for 5min in a second wash solution (SSC 0.1X, SDS 0.1%) at room temperature and rinsed five times for 1min at room temperature with a SSC 0.1X solution. The slides were dried upside down in a centrifuge at 1500rpm for 5min. The slides were scanned with a confocal laser scanner (ScanArrayTM Express, Perkin-Elmer Life Sciences, USA), and the spot intensities processed with the help of the ScanArray Express program (Packard BioScience), with a 10µm resolution and a PMT of 60% for Alexa 555 and of 70% for Alexa 647. Each slide generated a data set for each channel corresponding to the dyes Alexa 555 and Alexa 647. The slides were scanned with a confocal laser scanner (ScanArrayTM Express, Perkin-Elmer Life Sciences, USA) with a 10µm resolution and a PMT of 60% for Alexa 555 and of 70% for Alexa 647, and data were extracted with ScanArray Express software (Packard BioScience) using the histogram method. Each slide generated a data set for each channel corresponding to the dyes Alexa 555 and Alexa 647. The Locally Weighted Scatter-plot Smoothing method (LOWESS), adjusted for linear and non-linear systematic variations, both of the intensity dependent type, mainly for low intensity spots, was employed for data normalization.
Renato David Puga