Selective
drug delivery is an important approach with great potential for overcoming problems associated with the systemic toxicity and poor bioavailability of
antineoplastic drugs. Nanomedicine plays a pivotal role by delivering drugs in a targeted manner to the malignant
tumor cells thereby reducing the systemic toxicity of the anticancer drugs. The objective of this study was to prepare and characterize
rapamycin loaded polymeric
poly(lactide-co-glycolide) (PLGA) nanoparticles (NP) that were surface conjugated with
antibodies to
epidermal growth factor receptor (EGFR), highly expressed on
breast cancer cells, using 1-ethyl-3-(3-dimethylaminopropyl)
carbodiimide hydrochloride (EDC) and
N-hydroxysuccinimide (NHS) mediated cross linking agents. To potentiate the anticancer efficiency of the formulations, in vitro cytotoxicity of native
rapamycin,
rapamycin loaded nanoparticles and EGFR antibody conjugated
rapamycin loaded nanoparticles (EGFR-Rapa-NPs) were evaluated on malignant MCF 7
breast cancer cell lines. IC(50) doses as determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium (MTT) assay showed the superior antiproliferative activity of EGFR-Rapa-NPs over unconjugated nanoparticles and native
rapamycin due to higher cellular uptake on malignant
breast cancer cells. Cell cycle arrest and cellular apoptosis induced by the above formulations were confirmed by flow cytometry. Molecular basis of apoptosis studied by western blotting revealed the involvement of a cytoplasmic
protein in activating the programmed cell death pathway. Thus it was concluded that EGFR-Rapa-NPs provide an efficient and targeted delivery of anticancer drugs, presenting a promising active targeting carrier for
tumor selective therapeutic treatment in near future.