Ethylnitrosourea Induces Neoplasia in Zebrafish (Danio rerio)

Abstract

SUMMARY:The zebrafish (Danio rerio) has been successfully used to discover hundreds of genes involved in development and organogenesis. To address the potential of zebrafish as a cancer model, it is important to determine the susceptibility of zebrafish to tumors. Germ line mutations are most commonly induced for zebrafish mutant screens by exposing adult male zebrafish to the alkylating agent, ethylnitrosourea (ENU). To determine whether ENU induces tumors, we compared the incidence of tumors in ENU-treated fish with untreated controls. Interestingly, 18 of 18 (100%) fish mutagenized with either 2.5 or 3.0 mM ENU developed epidermal papillomas, which numbered 1 to 22 per fish, within 1 year of treatment. The induced epidermal lesions included epidermal hyperplasia, flat papillomas (0.2 to 1.2 mm), and pedunculated papillomas (1.2 to 8 mm in greatest dimension), but no skin cancers. Angiogenesis was evident in papillomas larger than approximately 1 mm. All but two papillomas contained the three cell types (keratinocytes, club, and mucous cells) of normal zebrafish epidermis; histologic variants lacked either club cells or mucous cells. Two cavernous hemangiomas and a single malignant peripheral nerve sheath tumor were also found in the treated fish. None of five untreated controls developed tumors. These studies establish the feasibility of the zebrafish as an experimental model for the study of skin tumors. (Lab Invest 2000, 80:379-385).

Catch of the day: zebrafish as a human cancer model

“…Water-soluble carcinogens can be added directly to the fish water and a number of chemical compounds that are carcinogenic in mammals induce tumor formation in zebrafish (Amatruda et al, 2002;Berghmans et al, 2005a;Goessling et al, 2007a, b). Exposure to dimethylbenzanthracene, ethylnitrosourea, N-methyl-N-nitro-Nnitrosoguanidine, diethylnitrosamine results in a variety of tumors in zebrafish or medaka (Oryzias latipes) (Okihiro and Hinton, 1999;Beckwith et al, 2000;Spitsbergen et al, 2000a, b;Mizgireuv et al, 2004;Lam and Gong, 2006;Mizgireuv and Revskoy, 2006). Most of the tumors that arise are hepatic but can also include other organs and tissues such as skin (papillomas), muscle (rhabdomyosarcomas and leiomyosarcomas), vasculature (hemangiosarcomas), testis (seminomas) and pancreas (pancreatic carcinomas) (Okihiro and Hinton, 1999;Beckwith et al, 2000;Spitsbergen et al, 2000a, b;Mizgireuv et al, 2004;Lam and Gong, 2006;Mizgireuv and Revskoy, 2006).…”

“…Exposure to dimethylbenzanthracene, ethylnitrosourea, N-methyl-N-nitro-Nnitrosoguanidine, diethylnitrosamine results in a variety of tumors in zebrafish or medaka (Oryzias latipes) (Okihiro and Hinton, 1999;Beckwith et al, 2000;Spitsbergen et al, 2000a, b;Mizgireuv et al, 2004;Lam and Gong, 2006;Mizgireuv and Revskoy, 2006). Most of the tumors that arise are hepatic but can also include other organs and tissues such as skin (papillomas), muscle (rhabdomyosarcomas and leiomyosarcomas), vasculature (hemangiosarcomas), testis (seminomas) and pancreas (pancreatic carcinomas) (Okihiro and Hinton, 1999;Beckwith et al, 2000;Spitsbergen et al, 2000a, b;Mizgireuv et al, 2004;Lam and Gong, 2006;Mizgireuv and Revskoy, 2006). The basic histological and molecular characteristics of chemically induced neoplasia in zebrafish show significant similarity to human cancer including increased cell proliferation, atypical nuclear morphology and low degree of cell differentiation.…”

Comparative aspects of zebrafish (Danio rerio) as a model for aging research

“…Tens to hundreds of milligrams of skeletal muscle may be isolated from a single fish, providing an ample supply of tissue for study. The pathologies zebrafish incur, such as various tumors, are morphologically similar to those found in mammals (Beckwith et al, 2000), yet the costs for such analyses are much less due to the smaller size of zebrafish.…”

“…Post-mitotic tissues, including skeletal muscle, brain, heart, and eye may thus be easily harvested for study. Replicating tissues may also be obtained, and zebrafish develop a wide variety of neoplasms with morphological similarity to mammalian tumors (Beckwith et al, 2000). Pathological analysis is also more cost-effective in zebrafish due to the ability to place an entire adult fish on a single microscope slide.…”

Zebrafish as a Cancer Model

“…Not surprisingly, the alkylating mutagen N-ethyl-N-nitrosourea, which introduces point mutations and is commonly used in forward and reverse genetic screens, has also been found to induce cancer. Following a group of animals from a mutagenesis screen, Beckwith et al (15) found that all fish developed skin papillomas over time, but not invasive skin cancers.…”