Development of Nanomedicine for the Treatment of Breast Cancer Metastases

siRNA delivery;breast cancer metastases;Biomedical Engineering;Engineering;Biomedical Engineering

Kaushal, NehaShea, Lonnie David ;

University of Michigan

关键词: siRNA delivery;    breast cancer metastases;    Biomedical Engineering;    Engineering;    Biomedical Engineering;   

Others  :  https://deepblue.lib.umich.edu/bitstream/handle/2027.42/137054/nkaus_1.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

RhoC-GTPase, a member of the Ras-superfamily of small guanosine triphosphatases (GTPases), is over-expressed in advanced breast cancer and has been implicated in highly motile and invasive cancer phenotypes. The overexpression of RhoC mRNA in advanced breast cancers suggests that it plays a role as a transformative oncogene for human mammary epithelial cells and as a potential marker to screen breast cancer patients with highly aggressive tumors and provide therapeutic interventions prior to the development of metastases. Short interfering RNA (siRNA) inhibits RhoC protein expression resulting in the suppression of breast cancer metastasis by inhibiting cancer cell invasion and migration. Transforming anti-RhoC siRNA into a clinically-viable therapy requires the development of biocompatible delivery systems that incorporate a large dose of siRNA and shuttle the therapeutic payload into the cytoplasm of aggressive breast cancer cells. This dissertation describes the development of peptide targeted, degradable, pH-sensitive, membrane-destabilizing β-cyclodextrin (β-CD) polymers that proved effective in condensing anti-RhoC siRNA to form ;;smart” nanoparticles. The peptide targeted ;;smart” nanoparticles facilitated selective homing into target breast cancer cells through receptor-mediated endocytosis and achieved functional delivery of anti-RhoC siRNA past the endosome into the cytoplasm of breast cancer cells resulting in the efficient knockdown of RhoC mRNA and protein levels.Specifically, we utilized the varying reactivity of the primary and secondary hydroxyl groups of the β-CD core to develop asymmetric ;;smart” polymers. The secondary hydroxyl groups were modified with amphiphilic copolymers comprising of pH-sensitive dimethyl aminoethyl methacrylate (DMAEMA) and hydrophobic hexyl methacrylate (HMA) monomers incorporated at a 50/50 molar feed ratio and grafted via acid-labile hydrazone linkages to form β-CD-P(HMA-co-DMAEMA) polymers. The β-CD-P(HMA-co-DMAEMA) polymers were stable at physiological pH, but rapidly degraded into membrane-active fragments at the acidic pH of the endosome. The siRNA molecules were complexed to the P(HMA-co-DMAEMA) grafts following the partial conversion of DMAEMA monomers into cationic TMAEMA monomers. The β-CD-P(HMA-co-DMAEMA-co-TMAEMA) polymers delivered anti-RhoC siRNA into the cytoplasm of SUM149 and MDA-MB-231 cells resulting in a 80-90% and 90-100% reduction in RhoC mRNA and protein levels, respectively. The incorporation of peptide targeted moieties to the free ends of polyethylene glycol (PEG) brushes on the primary face of the β-CD core resulted in selective accumulation of ;;smart” nanoparticles in breast cancer cells overexpressing underglycosylated Mucin 1 (uMUC1) surface receptors both in vitro and in vivo. Further, combining the peptide ligands and anti-RhoC siRNA molecules on the same asymmetric nanoparticle demonstrated a synergistic reduction in breast cancer cell invasion and migration in vitro. These results collectively confirm the successful development of a targeted, degradable ;;smart” nanoparticles that can enhance the functional delivery of anti-RhoC siRNA into the cytoplasm of aggressive breast cancer cell both in vitro and in vivo.