Abstract

To understand more about the lower generations of poly(amido amine) dendrimer (PAMAM) as a non-viral vector for antisense (ANS) therapy, a 21-mer epidermal growth factor receptor (EGFR) ANS was delivered by generation five of PAMAM in T47D breast carcinoma cells in culture. The semi-quantitative polymerase chain reaction (PCR) and western blot analysis were used to quantify the expression of EGFR mRNA and protein, respectively. The results showed that PAMAM G5/ANS nanoparticles were able to decrease the level of EGFR mRNA more than 40% even at the lower dendrimer primary amine to the antisense phosphate groups (N/P) ratio of 0.5. But, only the data of western blot analysis at the higher N/P ratios of 10 and 20 showed a decrease of the protein expression level similar to the mRNA expression level. Moreover, PAMAM dendrimer had a positive effect on the EGFR ANS action to inhibit the EGFR mRNA and protein expression. Further studies revealed that PAMAM G5 dendrimer as such inhibits the expression of EGFR in a concentration-dependent manner. Since PAMAM as such was able to inhibit the mRNA expression of p53 gene, we speculated that the effect of PAMAM G5 on the EGFR is a kind of its non-selective effect on the transcription and/or translation machinery of the cell.

Key words: Poly(amido amine) dendrimer (PAMAM) dendrimer, epidermal growth factor receptor (EGFR) antisense, epidermal growth factor, RNAi, polyamidoamine dendrimer, toxicogenomics, gene delivery.