51P - Gef gene: A new suicide gene therapy for non-small cell lung cancer

Date 17 April 2015
Event ELCC 2015
Session Poster lunch
Topics Lung and other Thoracic Tumours
Translational Research
Presenter Ana Rama Ballesteros
Citation Annals of Oncology (2015) 26 (suppl_1): 10-14. 10.1093/annonc/mdv045
Authors A.R. Rama Ballesteros, R. Hernández, G. Perazzoli, J. Oliver, L. Cabeza, C. Jiménez-Luna, M.C. Leiva, J. Jiménez, J. Prados
  • Anatomy And Embriology Human, Institute of Bio-pathology and Regenerative Medicine (IBIMER), 18100 - Granada/ES

Abstract

Aim/Background

Lung cancer is the main cause of cancer mortality worldwide. Chemotherapy and radiotherapy have been shown to be effective, but it often causes considerable toxicity. In recent years, gene therapy has been presented as a possibility to improve the response of patients with advanced lung cancer without damaging the normal host tissue. The classical suicide gene therapy is based on the use of genes from bacterial or viral origin whose encoding enzymes transform a nontoxic prodrug into a toxic molecule. The gef gene from E. coli encodes for a membrane protein with a toxic domain which does not need a prodrug. We investigated this gene as a new suicide gene therapy for treatment against non-small cell lung cancer (NSCLC).

Methods

The gef gene was cloned into the pcDNA3.1 vector (pcDNA3.1-gef) and the A-549 NSCLC line was cultured as monolayer (ML) and forming multicellular tumour spheroids (MTS). To study the growth-inhibitory effect of the gef gene, A-549 ML and MTS were transfected with pcDNA3.1-gef or empty pcDNA3.1 (control) and were compared with parental A-549 ML and MTS, respectively. A-549 ML was assessed by MTT assay and A-549 MTS by modulation of the volumes. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) analysis were used for ultrastructural analyses of transfected A-549 cells.

Results

The growth of the control cells was similar to that of the parental cells, while A-549/pcDNA3.1-gef showed a significant and time-dependent inhibition of growth (42.2% at 92 h). TEM revealed dilated mitochondria with clear matrices and disrupted cristae in the A-549/pcDNA3.1-gef; also, SEM showed a progressive disappearance of microvilli and membrane evaginations in the cell surface. Any feature was found in parental and control cells for both techniques. Volume analyses of A-549 MST showed similar findings to ML, with a significant and time-dependent volume decrease. The greatest volume decrease was 35.2% in A-549 MTS/pcDNA3.1-gef after 96 h in comparison with parental MTS. Control MTS displayed average volume like parental MTS.

Conclusions

Our results showed that the gef gene is able to inhibit A-549 line growth, displaying the gef gene as a new suicide gene therapy for treatment against NSCLC; its advantage being that it does not need a prodrug for its killing action.

Disclosure

All authors have declared no conflicts of interest.