Nanoparticle-facilitated Intratumoral Delivery of Bcl-2/IGF-1R siRNAs and p53 Gene Synergistically Inhibits Tumor Growth in Immunocompetent Mice

Anil Philip Kunnath

doi:10.4172/2157-7439.1000278

Abstract

Breast cancer, the leading cause of cancer-related deaths in women, is usually treated with surgery, radiation therapy, hormone-blocking/chemotherapy drugs, monoclonal antibodies or combinations of these approaches and agents depending on the cancer stage and the existence of specific receptors, with accompanying various adverse effects. Silencing of the genes responsible for cancer development and progression with small interfering RNA (siRNA) in combination with overexpression of the genes with tumor suppressing activities could be an attractive concept for precisely treating breast cancer with minimal side effects. However the short half-life in plasma due to nuclease-mediated degradation and renal clearance, and the inefficiency in penetrating the plasma membrane limit the applications of siRNA and DNA as therapeutic molecules. Recently, we have developed pH-sensitive carbonate apatite nano-carrier to efficiently deliver siRNA or DNA across the cell membrane facilitating them to escape endosomal acidic compartment and specifically cleave a cytoplasmic mRNA transcript or enable gene expression after nuclear translocation, respectively. Moreover, we demonstrated nanoparticle-accelerated delivery of the siRNAs targeting cyclin B1, PLC-gamma-2/ calmodulin1, HER2/ErbB2, ABCG2/ABCB1 and cROS1 mRNAs sensitizes cervical adenocarcinoma and breast cancer cells towards conventional anti-cancer drugs. Here, we report that co-delivery of the siRNAs targeting IGF-1R and Bcl-2 gene transcripts and the pasmid DNA containing p53 gene with the help of carbonate apatite nanoparticles synergistically induces inhibition of growth/proliferation of breast cancer cell lines as well as regression of the breast tumor induced in Balb/c mice. Additionally, concerted delivery of nanoparticle-associated IGF-1R/Bcl-2 siRNAs and p53 gene apparently slows down the growth of the established tumor in presence of doxorubicin or paclitaxel compared with the individual free drugs. Thus, the combination of IGF-1R/Bcl-2 knockdown and restoring of normal p53 function could be a highly promising approach that should be further investigated through pre-clinical trials to establish the therapeutic role of this combination therapy for breast cancer.

Highlights

Breast cancer is the most common female cancer with more than 400,000 annual deaths world-wide
-20 200 210 220 230 240 250 260 Wavelength mutated tumor suppressor genes, such as p53, and the cross-talks between them could contribute to the development of a variety of breast cancers, knockdown of Insulin-like growth factor (IGF)-1R and Bcl-2 transcripts and expression of wild-type p53 into breast cancer cells might block the cell proliferation and survival routes while stimulating apoptotic pathway
Carbonate apatite nanoparticles were used to complex with the small interfering RNA (siRNA) against IGF-1 receptor (IGF-1R) and Bcl-2 and p53 plasmid DNA, either individually or in combination, prior to the 48 h incubation with MCF-7 and 4T1

Summary

Introduction

Breast cancer is the most common female cancer with more than 400,000 annual deaths world-wide. We developed pH-responsive carbonate apatite nanoparticles to efficiently deliver siRNA as well as DNA across the cell membrane and facilitate them to release from the particles and endosomal vesicles to carry out knockdown of a specific mRNA transcript or expression of a desirable protein, respectively [32,33]. We report that combined delivery of the siRNA against IGF-1R and Bcl-2 gene transcripts along with p53 gene using carbonate apatite nanoparticles synergistically induces death or growth inhibition of breast cancer cell lines as well as regression of the breast tumor induced in Balb/c mice. Intravenous delivery of nanoparticle-associated IGF-1R/Bcl-2 siRNAs and p53 gene apparently slow down the growth of the established tumor in presence of doxorubicin or paclitaxel compared with the individual free drug

Materials and Methods

Results and Discussion

Conclusion