After 35 days of treatment, the animals were sacrificed and examined for gross tumor formation. A second group of mice underwent screening MRI to detect HCC at older than 6 months of life. Sixteen mice with index lesions (HCC) underwent determination of baseline tumor growth and were randomized to receive daily orogavage of either HPMT vehicle or PD0325901 (20 mg/kg). Serial MRIs were performed biweekly, and the tumor volume was determined. At the time of sacrifice, representative liver sections from different lobes were fixed in 10% formalin, paraffin embedded, and serially cut (5 μm). In vivo proton magnetic

resonance imaging ([1H]-MRI) of the mice with orthotopic tumors were http://www.selleckchem.com/products/Gemcitabine-Hydrochloride(Gemzar).html performed biweekly using a 9.4-Tesla, 31-cm horizontal bore system (Varian Inc, Palo Alto, CA) equipped with a 12-cm-diameter shielded gradient set capable of up to 38 gauss/cm gradient strength in three directions. The mice were anesthetized with 0.75% isofluorane delivered in medical air at 1 L/minute using a nose mask connected to a gas anesthesia machine (Vetland, Louisville, KY). The animal was positioned inside a 30-mm-diameter and 25-mm-high loop-gap volume coil tuned to 400 MHz. Warm air was blown through the magnet bore to maintain the

animal core body temperature at 35°C MG132 to 37°C, which was monitored with a fiber optic rectal probe (FISO Technologies, Quebec, Canada). Transaxial proton-density weighted images with fat suppression were obtained using a multi-slice spin-echo sequence and the following imaging parameters: field of view, 3 × 3 cm, slice thickness = 1 mm, number of slices = 20, matrix size = 256 × 128, signal averages = 2, repetition time (TR) = 1500 ms, and echo time (TE) = 15 msec. The total image data collection time was approximately 9 minutes. Acetophenone Tumor area was calculated by drawing a region of interest on the liver tumor slices using the Varian Browser software.

The area of tumor in each slice was multiplied by the slice thickness plus slice gap to calculate tumor volume per slice. The total tumor volume was obtained by adding the total area of all slices. Immunohistochemistry to detect DNA fragmentation was performed on formalin-fixed, paraffin-embedded liver sections using ApopTag Peroxidase In Situ Apoptosis Detection Kit (Millipore, Billerica, MA). Positively stained cells were counted in four fields (400×) with the highest density of staining per slide and expressed as a percentage relative to the total number of cells. The Fisher’s exact test was used for comparison of two groups with one observed variable. The Student t test was used for comparison of two groups, with P < 0.05 considered significant. The TAMH cell line, derived from TGF-α transgenic mouse hepatocytes, was exposed to PD0325901 (0-100 nM) for 1 or 24 hours. MEK activity reflected by the level of active, phosphorylated ERK (P-ERK) was determined by immunoblot (Fig. 1A).