Project title
肺癌自動轉移之實驗模式的基因體分析 (V)
Internal ID
NSC99-3112-B002-042
Principal Investigator
Start Date
May 1, 2010
End Date
April 30, 2011
Organizations
Partner Organizations
Genomic Analysis of a Spontaneous Model of Lung Cancer Metastasis (V) = 肺癌自動轉移之實驗模式的基因體分析 (V)
Keywords
metastasis
fucosyltransferase
microarray
genomics
proteomics
Description
Metastasis is a multistep process during which cancer cell spread from the site of primary tumor, circulate in blood stream and establish secondary tumor foci in distant organs. Recently, the understanding of metastasis has been expanded through microarray analysis. Many genes (Twist, snail, slug,..) had been shown to play very important roles in the metastasis of solid tumors. The establishment of experimental animal models, especially by spontaneous metastasis, contributes significantly to identify key molecule elements during metastasis. Modification of cell surface glycoprotein is one the critical step for cellular transformation. Aberrant glycosylation is common in cancers. We previously focused on the process of aberrant fucosylation and sialylation on the surface of cancer cells. The aberrant sugar antigens, such as sialyl Lewis x/a (sLex or sLea) or Lewis x/a antigens (Lex or Lea), may facilitate the survival of cancer cells in circulation and extravasation. These selecin ligands facilitate the formation of tumor cell-platelet-leukocyte emboli in blood stream and the transendothelial extravasation of tumor cells. By studying glycosyltransferase genes involving synthesizing sialylated Lewis and Lewis antigens, we demonstrated that overexpression of fucosyltransferase genes, such as FucT IV, are common in lung cancer, and associated with poor clinical outcome. A cell line (A549F4A4) which expressed high amount of fucosyltransferase IV gene can produce Lewis x antigen, and generate many metastatic nodules in the lung in a mice model of spontaneous metastasis. Hence, A549F4A4 cell line can generate an animal model of spontaneous lung cancer metastasis. Both the cell line and animal model will be great helpful for understanding pathophysiology of metastases in lung cancer. In the current proposal, using genomic and proteomic tools and animal model of spontaneous metastasis, we plan to identify specific gene targets important for every step of cancer metastasis, especially for site-specific metastasis to lung. A549F4A4 cell adheres to E-slectin and HUVEC cells (stimulated by TNF- and IL1-), but failed to activate platelet aggregation. In these two years, using cDNA microarray and proteomic methodology, genes overexpressed in A549F4A4 cells are identified and verified, and will be further investigated in tissue sections of lung cancer. A549F4A4 cell generates higher amount of fibrinogen, -1,-3,-5, -v and 1 integrins subunits, galectin-1, PRDX-1 and HSP27. Through probing glycoproteome by fucose analog, we identified several proteins that have underqent heavier fucosylation in A549F4A4 cell, all of these are membrane proteins related to important functions of tumor cells, like cell adhesion, cell-cell recognition and protease activity. TFPI-2, clusterin, cathepsin D are the molecules that we are specifically interested and work on. The preliminary results are: the expression of TFPI is measurable in lung cancer tissues and human sera. Higher expression of TFPI in lung cancer patient confer to a better survival. While most of the lung cancer tissue expressed Cathespin D, the clinical implication of Cathepsin D in lung cancer remains to be elucidated.