Preparation of 17-AAG loaded PLA/PEG Nanofibers for Targeting Genes Hsp90 and hTERT in A549 Lung Cancer Cells
Preparation of 17-AAG loaded PLA/PEG Nanofibers for Targeting Genes Hsp90 and hTERT in A549 Lung Cancer Cells
Sona Talaei,1,*Hasan Mellatyar,2
1. Department of Basic Sciences, Maragheh University of Medical Sciences, Maragheh, Iran 2. Department of Basic Sciences, Maragheh University of Medical Sciences, Maragheh, Iran
Introduction: The expression of heat shock protein 90 is increased in tumors such as lung cancer cells. 17-allylamino-17-demethoxygeldanamycin (17-AAG) with binding to Hsp90 ATP–binding pocket inhibits the formation of the multi-chaperone complex of Hsp90 that leads to degradation of the Hsp90 client proteins such as hTERT by the ubiquitin-proteasome system. Poor water-solubility of 17-AAG is a fundamental limitation for its clinical application. In the present study, to improve the solubility of 17-AAG, we developed implantable 17-AAG-loaded poly(lactide)-poly(ethylene glycol) (PLA-PEG) nanofibers.
Methods: 17-AAG-loaded PLA-PEG nanofibers were successfully fabricated by electrospinning method and characterized using Field Emission Scanning Electron Microscopy (FE-SEM) and Fourier Transform Infrared (FTIR). The colorimetric cell viability (MTT) assay was performed to evaluate the cytotoxic effects of free 17-AAG and 17-AAG-loaded PLA-PEG nanofibers. Cells were treated with equal concentrations of free 17-AAG and 17-AAG-loaded PLA-PEG nanofibers, and Hsp90 gene expression levels in the two groups were compared by real-time PCR. The effect of 17-AAG and 17-AAG loaded PLA-PEG nanofiber treatment on telomerase activity was monitored by TRAP assay.
Results: MTT assay confirmed that 17-AAG-loaded PLA-PEG nanofibers improved the cytotoxicity of 17-AAG in A549 cells. This finding was associated with a decrease in the expression of the Hsp90 gene and telomerase activity.
Conclusion: The results demonstrated that 17-AAG-loaded PLA-PEG nanofibers are more effective than free 17-AAG in down-regulating Hsp90 expression and inhibiting telomerase activity. Therefore, PLA-PEG nanofiber can be a superior carrier for this kind of hydrophobic agent.