title: [Study on the relationship between the abnormal expression of c-myc and multidrug resistance in KB cell lines].
abstract: OBJECTIVE
  To investigate the relationship between expression of c-myc and the regulation of mdr1, and find out the best way for gene therapy of the proliferative diseases with c-myc overexpression and reverse the multidrug resistance phenotype.
  
  
  METHODS
  The changes of c-Myc protein and P-gp in the KB cell lines were detected by using immunohistochemistry and flow cytometry methods before and after treatment with anti-mdr1- ribozyme.
  
  
  RESULTS
  All KB cell lines could express c-Myc protein. The expression of c-myc in multidrug resistant cell KBv displayed higher than that in sensitive cell KB. However, after reversing the multidrug resistance phenotype by anti-mdr1-ribozyme, the level of c-Myc protein expression was lower in KBv/5mR3 and KB/5mR3. The level of P-gp expression was lower in KBv/5mR3 than that in KBv but no difference in KB/5mR3 and KB.
  
  
  CONCLUSIONS
  There are a close relationship between Myc protein and MDR phenotype. The c-myc involves in regulating expression of mdr1. Myc protein can be used as a new assistant implement to monitor the formation of MDR.
authors.affiliation: Department of Otorhinolaryngolgy, Nanfang Hospital, First Military Medical University, Guangzhou 510510, China. ying-h@163.net
authors.forename: Y
authors.initials: Y
authors.lastname: He
authors.forename: J
authors.initials: J
authors.lastname: Zhang
authors.forename: J
authors.initials: J
authors.lastname: Zhang
mesh_terms: D018435:ATP Binding Cassette Transporter, Subfamily B / Q000096:biosynthesis; D018432:Drug Resistance, Multiple / Q000235:genetics* / Q000502:physiology; D019008:Drug Resistance, Neoplasm / Q000235:genetics* / Q000502:physiology; D005434:Flow Cytometry; D015972:Gene Expression Regulation, Neoplastic; D019450:Genes, MDR / Q000235:genetics; D016259:Genes, myc / Q000235:genetics*; D006801:Humans; D007624:KB Cells
chemical_list: D018435:ATP Binding Cassette Transporter, Subfamily B