New insight into the key proteins and pathways involved in the metastasis of colorectal carcinoma.

Metastasis-associated genomic alterations have been recognized to play a critical role in tumor metastasis. Primary and metastatic tumor cells in mice and tumors in a patient were studied by cDNA array analysis. Selected genes were determined by RT-PCR and immunohistochemistry. Pathways on changed genes were statistically analyzed. The function of Grb2 was determined by in vitro wound assay. Nodal metastatic cells had a stronger ability of growth and metastasis than primary tumor cells. A total of 376 genes showed a different expression between primary and metastatic cells. The expression of Grb2 and genes in the Grb2-mediated pathways was significantly elevated in the metastases. Elevated levels of Grb2 expression in metastases were related to the distant metastasis of colorectal carcinoma. Blocking the Grb2-SH2 domain signaling transduction inhibited cell motility. Metastasis-associated genes identified by cDNA and tissue microarrays provide potentially valuable information on the metastasis of colorectal tumors. Overexpression of Grb2 may contribute to tumor growth, invasiveness and metastasis.

Fluorescence excitation spectra of the b (1)Pi(u), b(') (1)Sigma(u) (+), c(n) (1)Pi(u), and c(n) (') (1)Sigma(u) (+) states of N(2) in the 80-100 nm region.

Fluorescence excitation spectra produced through photoexcitation of N(2) using synchrotron radiation in the spectral region between 80 and 100 nm have been studied. Two broadband detectors were employed to simultaneously monitor fluorescence in the 115-320 nm and 300-700 nm regions, respectively. The peaks in the vacuum ultraviolet fluorescence excitation spectra are found to correspond to excitation of absorption transitions from the ground electronic state to the b (1)Pi(u), b(') (1)Sigma(u) (+), c(n) (1)Pi(u) (with n=4-8), c(n) (') (1)Sigma(u) (+) (with n=5-9), and c(4) (')(v('))(1)Sigma(u) (+) (with v(')=0-8) states of N(2). The relative fluorescence production cross sections for the observed peaks are determined. No fluorescence has been produced through excitation of the most dominating absorption features of the b-X transition except for the (1,0), (5,0), (6,0), and (7,0) bands, in excellent agreement with recent lifetime measurements and theoretical calculations. Fluorescence peaks, which correlate with the long vibrational progressions of the c(4) (') (1)Sigma(u) (+) (with v(')=0-8) and the b(') (1)Sigma(u) (+) (with v(') up to 19), have been observed. The present results provide important information for further unraveling of complicated and intriguing interactions among the excited electronic states of N(2). Furthermore, solar photon excitation of N(2) leading to the production of c(4) (')(0) may provide useful data required for evaluating and analyzing dayglow models relevant to the interpretation of c(4) (')(0) in the atmospheres of Earth, Jupiter, Saturn, Titan, and Triton.