Hypoxia-induced resistance to cisplatin and doxorubicin in non-small cell lung cancer is inhibited by silencing of HIF-1alpha gene

Cancer Chemother Pharmacol. 2006 Dec;58(6):776-84. doi: 10.1007/s00280-006-0224-7. Epub 2006 Mar 11.


Objectives: Hypoxia is associated with human non-small cell lung cancers (NSCLC), which are highly resistant to chemotherapy. The hypoxia inducible factor (HIF) as a transcription factor in response to hypoxia indicates that it could be a novel, tumor-specific target for anticancer therapy. We hypothesized that disruption of HIF pathway through lentiviral vector-mediated HIF-1alpha RNA interference (RNAi) could reverse the hypoxia-induced resistance to chemotherapy.

Methods: We transfected Human NSCLC cell lines, SPCA1 and A549 with HIF-1alpha specific RNAi lentiviral vectors as well as controls. HIF-1alpha silenced cells [SPCA1/HIF-1alpha(-) and A549/HIF-1alpha(-)] were screened by blasticidin. They were incubated in 19 or 0.5% O2 for 16 h followed by the assessment of chemosensitivity to cisplatin and doxorubicin with MTT and clonogenic assays. Quantitative RT-PCR and Western blot analysis were used to detect the expressions of HIF-1alpha mRNA and protein, respectively. Moreover, flow cytometry was used to monitor the expression of P-glycoprotein.

Results: Exposure of SPCA1 and A549 cells to 0.5% O2 significantly increased resistance to cisplatin and doxorubicin, in contrast to cells incubated in normoxia. Transduction of SPCA1 with HIF-1alpha RNAi vector resulted in sequence specific silencing with 87.2 and 84.6% decreases of HIF-1alpha mRNA transcription and 97.3 and 94.8% of protein expressions in normoxia and hypoxia, respectively. Correspondingly, they are 89.2, 89.9% and 97.2, 88.4% decreases in A549 cells. Hypoxia-induced resistance to cisplatin and doxorubicin were reversed in SPCA1/HIF-1alpha(-) and A549/HIF-1alpha(-) cells. There was no significant P-glycoprotein increase induced by hypoxia in NSCLC cells.

Conclusions: Our studies demonstrated that hypoxia-induced chemoresistance to cisplatin and doxorubicin in NSCLC cells is through the HIF pathway. MDR1 regulation may not be involved in hypoxia-induced chemoresistance. Combining delivery of HIF-1alpha RNAi lentiviral vector with cisplatin-related chemotherapy regimens may enable us to develop more effective strategy for NSCLC therapy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ATP Binding Cassette Transporter, Subfamily B, Member 1 / metabolism
  • Antineoplastic Agents / pharmacology
  • Carcinoma, Non-Small-Cell Lung / genetics
  • Carcinoma, Non-Small-Cell Lung / metabolism
  • Carcinoma, Non-Small-Cell Lung / pathology
  • Cell Hypoxia / physiology
  • Cell Line, Tumor
  • Cell Survival / drug effects
  • Cisplatin / pharmacology*
  • Doxorubicin / pharmacology*
  • Drug Resistance, Neoplasm / genetics
  • Drug Resistance, Neoplasm / physiology*
  • Flow Cytometry
  • Gene Expression / genetics
  • Humans
  • Hypoxia-Inducible Factor 1, alpha Subunit / genetics
  • Hypoxia-Inducible Factor 1, alpha Subunit / physiology*
  • Inhibitory Concentration 50
  • Lung Neoplasms / genetics
  • Lung Neoplasms / metabolism
  • Lung Neoplasms / pathology
  • Oxygen / metabolism
  • RNA Interference / physiology*
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Reverse Transcriptase Polymerase Chain Reaction


  • ATP Binding Cassette Transporter, Subfamily B, Member 1
  • Antineoplastic Agents
  • HIF1A protein, human
  • Hypoxia-Inducible Factor 1, alpha Subunit
  • RNA, Messenger
  • Doxorubicin
  • Cisplatin
  • Oxygen