Epidermal growth factor regulates topoisomerase II activity and drug sensitivity in human KB cells

G. C. Allen, S. Lubas, Mark Wax, R. F. DeVore

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Because of its unique DNA-cleaving and strand-passing activities, topoisomerase II is involved in many aspects of DNA metabolism, including replication, transcription, recombination, and repair. The cytotoxic potential of topoisomerase II-targeted drugs, such as etoposide, is related to their ability to stabilize covalently linked enzyme-DNA complexes, which are intermediates in the enzyme's catalytic cycle. Epidermal growth factor receptor is expressed on the cell surface of the majority of squamous cell carcinomas, and epidermal growth factor binding is known to stimulate a number of cellular transduction pathways, including tyrosine kinase, protein kinase C, and phospholipase C. Because topoisomerase II is a proliferation- dependent protein and has been shown to be a high-affinity substrate for many of these cellular transduction pathways, the effects of epidermal growth factor on cellular regulation and sensitivity to etoposide were studied with the human oral cavity squamous cell line, KB. Topoisomerase II catalytic activity was rapidly and transiently inhibited after the addition at epidermal growth factor to the cellular growth media. Western blot on nuclear extracts did not demonstrate alterations in topoisomerase II polypeptide levels to account for changes in catalytic activity. Epidermal growth factor treatment also led to the formation of stabilized, covalently linked enzyme- DNA complexes. Furthermore, epidermal growth factor-induced, topoisomerase II-mediated DNA strand breaks were additive to those induced by etoposide. This study indicates that epidermal growth factor specifically regulates the catalytic and DNA-cleaving activities of topoisomerase II in KB cells. This may direct clinical strategies for circumventing the intrinsic cellular resistance to chemotherapy commonly observed in squamous cell carcinomas of the head and neck.

Original languageEnglish (US)
Pages (from-to)785-792
Number of pages8
JournalOtolaryngology - Head and Neck Surgery
Volume114
Issue number6
DOIs
StatePublished - 1996
Externally publishedYes

Fingerprint

KB Cells
Type II DNA Topoisomerase
Epidermal Growth Factor
Pharmaceutical Preparations
Etoposide
DNA
Enzymes
Catalytic DNA
Recombinational DNA Repair
DNA Breaks
Type C Phospholipases
Epidermal Growth Factor Receptor
Protein-Tyrosine Kinases
Protein Kinase C
Mouth
Squamous Cell Carcinoma
Western Blotting
Epithelial Cells
Drug Therapy
Cell Line

ASJC Scopus subject areas

  • Otorhinolaryngology

Cite this

Epidermal growth factor regulates topoisomerase II activity and drug sensitivity in human KB cells. / Allen, G. C.; Lubas, S.; Wax, Mark; DeVore, R. F.

In: Otolaryngology - Head and Neck Surgery, Vol. 114, No. 6, 1996, p. 785-792.

Research output: Contribution to journalArticle

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