title: Clonal evolution and progression of 20-methylcholanthrene-induced squamous cell carcinoma of mouse epidermis as revealed by DNA instability and other malignancy markers.
abstract: We examined the clonal evolution of skin malignant lesions by repeated topical applications of 20-methylcholanthrene (20-MC) to the skin, which induces hyperplastic epidermis, papillomatous lesion and invasive carcinoma in mice. The lesions were examined histologically and immunohistochemically with anti-single-stranded DNA after acid hydrolysis (DNA-instability test), p53, VEGF, DFF45, PCNA and AgNORs parameters analyses. Multiple clones with increased DNA instability comparable to that of invasive carcinoma were noted in early-stage (2-6 weeks) hyperplastic epidermis, and their number increased in middle (7-11 weeks), and late-stages (12-25 weeks) of hyperplastic epidermis, indicating that they belong to the malignancy category. All papillomatous lesions and invasive carcinomas showed a positive DNA-instability test. Positive immunostaining for various biomarkers and AgNORs parameters appeared in clones with a positive DNA-instability test in early-or middle-stage hyperplastic epidermis, and markedly increased in late-stage hyperplastic epidermis, papillomatous lesions and invasive carcinomas. The percentage of PCNA-positive vascular endothelial cells was significantly higher in VEGF-positive lesions with a positive DNA-instability test and became higher toward the late-stage of progression. Cut-woundings were made to papillomatous and invasive carcinoma lesions, and the regeneration activity of vascular endothelial cells was determined by using flash labeling with tritiated thymidine (3H-TdR). In small papillomatous lesions, vascular endothelial cells showed regenerative response, but the response was weak in large lesions. No such response was noted in invasive carcinomas; rather, cut-wounding induced collapse of blood vessels, which in turn induced massive coagulative necrosis of cancer cells. These responses can be interpreted to reflect exhausted vascular growth activity due to excessive stimulation by VEGF-overexpression, which was persistently seen from hyperplastic epidermis to invasive carcinoma.
authors.affiliation: Department of Dermatology, Fukui Medical University, Yoshida-Gun, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Hirai
authors.forename: M
authors.initials: M
authors.lastname: Kumakiri
authors.forename: K
authors.initials: K
authors.lastname: Ueda
authors.forename: Y
authors.initials: Y
authors.lastname: Imamura
authors.forename: S
authors.initials: S
authors.lastname: Noriki
authors.forename: Y
authors.initials: Y
authors.lastname: Nishi
authors.forename: H
authors.initials: H
authors.lastname: Kato
authors.forename: M
authors.initials: M
authors.lastname: Fukuda
mesh_terms: D000818:Animals; D018952:Antigens, CD34 / Q000032:analysis; D051017:Apoptosis Regulatory Proteins; D014408:Biomarkers, Tumor / Q000032:analysis*; D002273:Carcinogens / Q000009:adverse effects; D002294:Carcinoma, Squamous Cell / Q000139:chemically induced / Q000737:chemistry* / Q000473:pathology; D004273:DNA, Neoplasm / Q000032:analysis*; D004195:Disease Models, Animal; D016228:Endothelial Growth Factors / Q000032:analysis; D007150:Immunohistochemistry / Q000379:methods; D008222:Lymphokines / Q000032:analysis; D008297:Male; D008748:Methylcholanthrene / Q000009:adverse effects; D051379:Mice; D018809:Proliferating Cell Nuclear Antigen / Q000032:analysis; D011506:Proteins / Q000032:analysis; D012878:Skin Neoplasms / Q000139:chemically induced / Q000737:chemistry* / Q000473:pathology; D013194:Staining and Labeling / Q000379:methods; D016159:Tumor Suppressor Protein p53 / Q000032:analysis; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
chemical_list: D018952:Antigens, CD34; D051017:Apoptosis Regulatory Proteins; D014408:Biomarkers, Tumor; D002273:Carcinogens; D004273:DNA, Neoplasm; D016228:Endothelial Growth Factors; D008222:Lymphokines; D018809:Proliferating Cell Nuclear Antigen; D011506:Proteins; D016159:Tumor Suppressor Protein p53; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; C109664:caspase-activated DNase inhibitor; D008748:Methylcholanthrene