Downregulation of apoptosis revealed by laser microdissection and cDNA microarray analysis of related genes in rat liver preneoplastic lesions.
Regulation of cell proliferation and apoptosis plays a key role in tumor development. To elucidate mechanisms underlying hepatocarcinogenesis, patterns of gene expression, including apoptosis-related genes, were compared between glutathione S-transferase placental form (GST-P)-positive preneoplastic foci and surrounding tissue in the rat. Lesions were induced with a single intraperitoneal injection of diethylnitrosamine (DEN, 200 mg/kg bw) and then 100 ppm 2-acetylaminofluorene (2-AAF)-containing diet combined with two-thirds partial hepatectomy. Frozen sections of the livers were applied for immunohistochemical staining of GST-P, and both positive foci and surrounding negative areas were harvested by laser microdissection. Total RNAs were extracted and amplified with T7 polymerase to allow gene expression analysis by cDNA microarray assays. In the GST-P-positive foci, altered levels were observed for many genes, mostly related to metabolism or catalysis, with increased expression of testosterone-repressive prostate message-2 (TRPM-2), which is reported to act as a protective factor against apoptosis, and decreased expression of thymus-expressed acidic protein (TEAP), which is considered to promote apoptosis. The results indicate that rat liver preneoplastic lesions might be protected against apoptosis and that the approach adopted is useful for clarification of mechanisms underlying hepatocarcinogenesis.
Ogawa
Kumiko
K
Department of Experimental Pathology and Tumor Biology, Nagoya City University Graduate School of Medical Sciences, Mizuho-cho, Mizuho-ku, Japan. kogawa@med.nagoya-cu.ac.jp
Asamoto
Makoto
M
Suzuki
Shugo
S
Tsujimura
Kazunari
K
Shirai
Tomoyuki
T
D000477:Alkylating Agents / Q000633:toxicity; D000818:Animals; D017209:Apoptosis / Q000235:genetics*; D004052:Diethylnitrosamine / Q000633:toxicity; D015536:Down-Regulation; D005260:Female; D020869:Gene Expression Profiling / Q000379:methods; D015972:Gene Expression Regulation, Neoplastic; D007834:Lasers; D008113:Liver Neoplasms / Q000139:chemically induced / Q000235:genetics*; D042282:Microdissection; D020411:Oligonucleotide Array Sequence Analysis; D011230:Precancerous Conditions / Q000139:chemically induced / Q000235:genetics* / Q000473:pathology; D020871:RNA Stability / Q000187:drug effects; D051381:Rats; D011916:Rats, Inbred F344
D000477:Alkylating Agents; D004052:Diethylnitrosamine