Send to

Choose Destination
Proc Natl Acad Sci U S A. 1992 Sep 1;89(17):8165-9.

Elimination of extrachromosomally amplified MYC genes from human tumor cells reduces their tumorigenicity.

Author information

Department of Medicine, University of Texas Health Science Center, San Antonio 78284.


Oncogene amplification has been observed in a broad spectrum of human tumors and has been associated with a poor prognosis for patients with several different types of malignancies. Importantly, at biopsy, the amplified genes localize to acentric extrachromosomal elements such as double-minute chromosomes (DMs) in the vast majority of cases. We show here that treatment of several human tumor cell lines with low concentrations of hydroxyurea accelerates the loss of their extrachromosomally amplified oncogenes. The decreases in MYC copy number in a human tumor cell line correlated with a dramatic reduction in cloning efficiency in soft agar and tumorigenicity in nude mice. No effect on gene copy number or tumorigenicity was observed for a closely related cell line containing the same number of chromosomally amplified MYC genes. One step involved in the accelerated loss of extrachromosomal elements is shown to involve their preferential entrapment of DMs within micronuclei. The data suggest that agents that accelerate the loss of extrachromosomally amplified genes could provide valuable tools for moderating the growth of a large number of human neoplasms.

[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for HighWire Icon for PubMed Central
Loading ...
Support Center