Biomaterial Database

Enhancement of the chemical transformation of Chinese hamster embryo cells in vitro by 7-methylguanine. 1987

G Muralidhar, and R W Trewyn

The RNA catabolite 7-methylguanine has been shown to inhibit queuine modification of tRNA in Chinese hamster embryo cells under conditions leading to in vitro transformation. Phorbol ester tumor promoters also induce queuine hypomodification of tRNA in normal human cells, and this effect was reported to be correlated directly to the appearance of an altered (transformed) cell phenotype. Based on this common macromolecular alteration, 7-methylguanine was evaluated for its ability to enhance the chemically induced transformation of cultured cells. Two-stage initiation-promotion experiments were undertaken with Chinese hamster embryo cells in vitro to compare the effects of 7-methylguanine to known tumor promoters subsequent to initiation with 3-methylcholanthrene. 7-Methylguanine was able to increase significantly the expression of type III foci as well as anchorage-independent growth, thereby confirming that it can act as a promoting agent in vitro. Methylated guanines that do not induce queuine hypomodification of tRNA were not capable of enhancing these characteristics of in vitro transformation. The results suggest that 7-methylguanine may be a natural, endogenous promoting agent, and that changes in queuine modification of tRNA may play a fundamental role in the promotion of carcinogenesis.

UI	MeSH Term	Description	Entries
D010641	Phenotype	The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.	Phenotypes
D010703	Phorbol Esters	Tumor-promoting compounds obtained from CROTON OIL (Croton tiglium). Some of these are used in cell biological experiments as activators of protein kinase C.	Phorbol Diester,Phorbol Ester,Phorbol Diesters,Diester, Phorbol,Diesters, Phorbol,Ester, Phorbol,Esters, Phorbol
D011247	Pregnancy	The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.	Gestation,Pregnancies
D002471	Cell Transformation, Neoplastic	Cell changes manifested by escape from control mechanisms, increased growth potential, alterations in the cell surface, karyotypic abnormalities, morphological and biochemical deviations from the norm, and other attributes conferring the ability to invade, metastasize, and kill.	Neoplastic Transformation, Cell,Neoplastic Cell Transformation,Transformation, Neoplastic Cell,Tumorigenic Transformation,Cell Neoplastic Transformation,Cell Neoplastic Transformations,Cell Transformations, Neoplastic,Neoplastic Cell Transformations,Neoplastic Transformations, Cell,Transformation, Cell Neoplastic,Transformation, Tumorigenic,Transformations, Cell Neoplastic,Transformations, Neoplastic Cell,Transformations, Tumorigenic,Tumorigenic Transformations
D003412	Cricetulus	A genus of the family Muridae consisting of eleven species. C. migratorius, the grey or Armenian hamster, and C. griseus, the Chinese hamster, are the two species used in biomedical research.	Hamsters, Armenian,Hamsters, Chinese,Hamsters, Grey,Armenian Hamster,Armenian Hamsters,Chinese Hamster,Chinese Hamsters,Grey Hamster,Grey Hamsters,Hamster, Armenian,Hamster, Chinese,Hamster, Grey
D005260	Female		Females
D006147	Guanine
D006224	Cricetinae	A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.	Cricetus,Hamsters,Hamster
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D012343	RNA, Transfer	The small RNA molecules, 73-80 nucleotides long, that function during translation (TRANSLATION, GENETIC) to align AMINO ACIDS at the RIBOSOMES in a sequence determined by the mRNA (RNA, MESSENGER). There are about 30 different transfer RNAs. Each recognizes a specific CODON set on the mRNA through its own ANTICODON and as aminoacyl tRNAs (RNA, TRANSFER, AMINO ACYL), each carries a specific amino acid to the ribosome to add to the elongating peptide chains.	Suppressor Transfer RNA,Transfer RNA,tRNA,RNA, Transfer, Suppressor,Transfer RNA, Suppressor,RNA, Suppressor Transfer