Folate-Conjugated Halloysite Nanotubes, an Efficient Drug Carrier, Deliver Doxorubicin for Targeted Therapy of Breast Cancer

Abstract

To carry doxorubicin (DOX) on breast cancer site effectively, halloysite nanotubes conjugated with poly­(ethylene glycol) and folate (HNTs-PEG-FA) is designed as a targeted drug delivery system. Halloysite nanotubes (HNTs) are shortened to ∼200 nm by ultrasonic scission and functionalized with amide groups to conjugate with N-hydroxylsuccinimide-polyethylene glycol carboxylic acid (NHS-PEG-COOH) and folate (FA). DOX@HNTs-PEG-FA is prepared by loading DOX on HNTs-PEG-FA via physical adsorption. The sustained and controlled release of DOX from DOX@HNTs-PEG-FA is up to 35 h in an acidic environment (pH 5.3). DOX@HNTs-PEG-FA, performed as a new nanodelivery system, shows significant inhibition of proliferation and induction of death in MCF-7 cells with positive FA receptor but not in L02 cells with negative FA receptor. Results of acridine orange/ethidium bromide and flow cytometric assay indicate that DOX@HNTs-PEG-FA induces cell death through apoptosis. Compared to the same dose of DOX, DOX@HNTs-PEG-FA generates more reactive oxygen species (ROS) in MCF-7 cells, which lead to mitochondrial damage and apoptosis. Furthermore, with fluorescence images and transmission electron microscopy, uptake of DOX@HNTs-PEG-FA by tumor cells is both through endocytosis and direct penetration mechanism. The in vivo antibreast cancer activity of DOX@HNTs-PEG-FA is further confirmed in 4T1-bearing mice. In contrast to DOX, DOX@HNTs-PEG-FA effectively reduces heart toxicity and inhibits solid tumor growth with higher cleaved caspase-3 protein level in tumor tissue of 4T1-bearing mice. DOX@HNTs-PEG-FA reveals a higher DOX fluorescence intensity in tumor tissue than in other normal tissues including heart, spleen, lung, and kidney at different time points. All these results suggest that FA-conjugated HNTs may be designed to be a novel drug delivery system for targeted therapy of breast cancer via intravenous injection.

Cellular Analysis and Chemotherapeutic Potential of a Bi-Functionalized Halloysite Nanotube

“…FA-conjugated chitosan oligosaccharide-magnetic HNTs were studied as a delivery system for camptothecin, an anti-cancer drug [ 37 ]. Wu et al (2018) also functionalized the HNT surface with APTES for conjugation of PEG and folic acid and subsequently loaded HNTs with doxorubicin [ 38 ]. The limitation of their study was the reported low drug loading efficiency, which was only 3%.…”

Citrate- and Succinate-Modified Carbonate Apatite Nanoparticles with Loaded Doxorubicin Exhibit Potent Anticancer Activity against Breast Cancer Cells

“…However, HNTs negatively charged surface (−16.5 ± 1.2 mV) requires positively charged drugs to bind, restricting the binding opportunity for negatively charged drugs. In another study, HNTs were conjugated with poly(ethylene glycol) (PEG) and folate (FA) to formulate HNTs-PEG-FA complexes for targeted DOX delivery into breast tumors [ 47 ]. HNTs-PEG-FA complexes possessed only 3% DOX loading efficiency and almost 35% cell viability for 8.0 × 10 3 MCF-7 cells/well at a concentration of 10 µg/mL DOX.…”

Biomedical Applications of Nanomaterials: Nanotubes and Metal-Organic Frameworks (MOFs)

“…The DOXO@ HNTs-PEG-FA reduced toxicity and inhibited tumour growth associated with higher levels of caspase-3 protein. These results suggest that FA-conjugated HNTs may be designed to be a novel drug delivery system for targeted therapy of breast cancer via intravenous [9]. Diagram for the preparation of DOX@ZIF-HA and the Fe 3+ -mediated coordination interaction between HA and PDA [8].…”