Resistance to chemotherapeutic drugs overcome by c-Myc inhibition in a Lewis lung carcinoma murine model.

Journal Article (Journal Article)

Chemotherapy resistance is a significant obstacle in lung cancer therapy, and has been found to frequently correlate with amplification and overexpression of the c-myc oncogene. Earlier studies have shown that c-Myc inhibition alone is not always effective in cancer models. The purpose of this study was to test different dosing regimen, which included commonly used chemotherapeutic drugs in combination with c-Myc inhibition in a Lewis lung syngeneic drug-resistant murine tumor model. Inhibition of c-myc was specifically achieved by using phosphorodiamidate Morpholino oligomer (PMOs), a novel, non-toxic antisense DNA chemistry for inhibition of gene expression by an RNase H-independent mechanism. When administration of cisplatin overlapped with c-myc PMO (AVI-4126) treatment there was no additional effect on tumor growth inhibition compared to cisplatin alone. In contrast, using a dosing regimen in which cisplatin or taxol treatment preceded AVI-4126, a dramatic decrease in tumor growth rate was observed with tumor areas less then 0.5 cm2 in 60% of the animals at the end of the study. This effect was specific to c-Myc inhibition as other antisense PMOs against p21 or Rad51 showed no such effect in combination with chemotherapy. Immunoblot and HPLC-based analysis of tumor lysates at the end of the study confirmed c-Myc inhibition and detection of intact AVI-4126, respectively. In conclusion, AVI-4126 potentiates the efficacy of chemotherapeutic drugs in a manner that is schedule dependent.

Full Text

Duke Authors

Cited Authors

  • Knapp, DC; Mata, JE; Reddy, MT; Devi, GR; Iversen, PL

Published Date

  • January 2003

Published In

Volume / Issue

  • 14 / 1

Start / End Page

  • 39 - 47

PubMed ID

  • 12544257

International Standard Serial Number (ISSN)

  • 0959-4973

Digital Object Identifier (DOI)

  • 10.1097/00001813-200301000-00006


  • eng

Conference Location

  • England