Expressions of junB and c-fos are enhanced in 4-nitroquinoline 1-oxide-induced rat tongue cancers.

Abstract

Activator protein-1 (AP-1) is a transcription factor activated in many tumors. Using 4-nitroquinoline 1-oxide (4NQO)-induced rat tongue cancers (TC), the present study investigated the expression levels of genes that encode the components of AP-1, the jun gene family (c-jun, junB and junD) and the fos gene family (c-fos, fra-1, fra-2 and fosB). Expression levels of junB and c-fos mRNAs in TC were significantly elevated compared with those in epithelial tissue of control rat tongue, although only c-fos mRNA levels tended to be elevated in dysplastic tongue epithelium. Histologically, all 4NQO-induced rat TC were well-differentiated squamous cell carcinomas. Immunostaining for JunB and c-Fos proteins was positive in the nuclei of tumor cells of all TC. It is noteworthy that JunB was negative, but c-Fos was positive in the dysplastic tongue epithelium of the 4NQO-treated rats. Immunostaining for both proteins was negative in tongue mucosal epithelium of control rats. There were no mutations in the coding regions of either junB or c-fos in all the TC examined. These results suggest the possibility that the expressions of junB and c-fos were enhanced stepwise in 4NQO-induced carcinogenesis of rat tongue, and that the coexpression of JunB and c-Fos might play an important role in the establishment of TC.

• Authors: Masanobu Ohyama, Yoshikazu Hirayama, Jun-ichi Tanuma, Masato Hirano, Ichiro Semba, Hayase Shisa, Hiroshi Hiai, Kazumasa Sugihara, Motoo Kitano
• Journal: Pathology international (Pathol Int) Vol. 54 Issue 1 Pg. 35-40 (Jan 2004) ISSN: 1440-1827 [Electronic] Australia
• PMID: 14674993 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Biomarkers, Tumor
• Proto-Oncogene Proteins c-jun
• RNA, Messenger
• RNA, Neoplasm
• 4-Nitroquinoline-1-oxide

Topics

• 4-Nitroquinoline-1-oxide (toxicity)
• Animals
• Biomarkers, Tumor (analysis)
• Carcinoma, Squamous Cell (chemically induced, genetics, pathology)
• Cell Nucleus (chemistry, pathology)
• Disease Models, Animal
• Gene Expression Regulation, Neoplastic
• Genes, fos (genetics)
• Proto-Oncogene Proteins c-jun (genetics)
• RNA, Messenger (metabolism)
• RNA, Neoplasm (analysis)
• Rats
• Rats, Inbred Strains
• Tongue (chemistry, drug effects, pathology)
• Tongue Neoplasms (chemically induced, genetics, pathology)