Study of inhibitory effect of PCL-17-AAG nanofiber on hsp90 gene expression and hTERT protein synthesis in T47D breast cancer cell line

Abstract

Introduction: Up-regulation of Hsp90 gene takes place in breast cancer cells. Therefore, targeting the Hsp90 in breast cancer may be promising step in breast cancer therapy. The present study aimed to evaluate the efficiency of implantable 17-allylamino-17-demethoxygeldanamycin (17-AAG)-loaded poly(ε-caprolactone)-poly (ethylene glycol) (PCL-PEG) nanofibers to increase the anti-cancer effects via inhibition of Hsp90 expression. Methods: For this purpose, 17-AAG-loaded PCL-PEG nanofibers were successfully fabricated via electrospinning technique and characterized using Field Emission Scanning Electron Microscopy (FE-SEM) and Fourier Transform Infrared (FTIR). The release profile of drug from the drug-loading nanofibers was studied by incubating nanofiber in the release media. Colorimetric MTT metabolic activity assay was used to determine the 17-AAG and 17-AAG-loading nanofibers cytotoxicity on T47D cells. Also, Hsp90 mRNA expression levels and activity of telomerase in treated cells with 17-AAG-loaded PCL-PEG nanofiber and free 17-AAG was monitored by real-time PCR and TRAP assay, respectively. Results: Microscopic studies indicated the loading of 17-AAG into the PCL-PEG nanofiber, successfully. MTT assay confirmed that 17-AAG-loaded PCL-PEG nanofiber enhanced 17-AAG cytotoxicity in T47D cells. This finding was associated with decrease of Hsp90 mRNA expression and telomerase activity in treated cells with 17-AAG-loaded PCL-PEG nanofiber in comparison with free 17-AAG. Conclusions: 17-AAG-loaded PCL-PEG nanofibers can be more effective than free 17-AAG to down-regulate Hsp90 expression and inhibit telomerase activity in T47D cells. Therefore, PCL-PEG could be a superior carrier for this type of hydrophobic agent.