Folic acid-capped PEGylated magnetic nanoparticles enter cancer cells mostly via clathrin-dependent endocytosis

• Published in: Biochimica et biophysica acta. General subjects Vol. 1861; no. 6; pp. 1578 - 1586
• Main Authors: Allard-Vannier, Emilie, Hervé-Aubert, Katel, Kaaki, Karine, Blondy, Thibaut, Shebanova, Anastasia, Shaitan, Konstantin V., Ignatova, Anastasia A., Saboungi, Marie-Louise, Feofanov, Alexey V., Chourpa, Igor
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.06.2017; Elsevier
• Subjects: Analytical chemistry; Antibiotics, Antineoplastic - chemistry; Antibiotics, Antineoplastic - metabolism; Antibiotics, Antineoplastic - pharmacology; Bioengineering; Biomaterials; Breast Neoplasms - drug therapy; Breast Neoplasms - metabolism; Cancer; Caveolae - metabolism; Caveolae-dependent endocytosis (CvDE); cell membranes; chemical bonding; chemical elements; Chemical Sciences; Clathrin - metabolism; Clathrin-Coated Vesicles - metabolism; Clathrin-dependent endocytosis (CDE); confocal laser scanning microscopy; Confocal laser-scanning microscopy (CLSM); doxorubicin; Doxorubicin - chemistry; Doxorubicin - metabolism; Doxorubicin - pharmacology; Drug Carriers; Electron energy loss spectroscopy (EELS); Endocytosis; Endosomes - metabolism; Female; fluorescence emission spectroscopy; fluorescent dyes; folic acid; Folic acid (FA); Folic Acid - chemistry; Folic Acid - metabolism; HeLa Cells; High angle annular dark field scanning transmission electron microscopy (HAADF-STEM); Humans; hydrodynamics; Imaging; iron oxides; Life Sciences; lysosomes; Lysosomes - metabolism; Magnetics - methods; Magnetite Nanoparticles - chemistry; MCF-7 Cells; Microscopy, Confocal; Microscopy, Electron, Scanning Transmission; Microscopy, Fluorescence, Multiphoton; Nanomedicine - methods; nanoparticles; neoplasm cells; neoplasms; optical properties; polyethylene glycol; Polyethylene Glycols - chemistry; Spectroscopy, Electron Energy-Loss; Superparamagnetic iron oxide nanoparticles (SPIONs); transmission electron microscopy; Two-photon excited (TPE) fluorescence; Uterine Cervical Neoplasms - drug therapy; Uterine Cervical Neoplasms - metabolism; zeta potential; Folic acid (FA); Confocal laser-scanning microscopy (CLSM); High angle annular dark field scanning transmission electron microscopy (HAADF-STEM); Superparamagnetic iron oxide nanoparticles (SPIONs); Clathrin-dependent endocytosis (CDE); Caveolae-dependent endocytosis (CvDE); Two-photon excited (TPE) fluorescence; Electron energy loss spectroscopy (EELS)
• ISSN: 0304-4165; 1872-8006
• DOI: 10.1016/j.bbagen.2016.11.045

This work is focused on mechanisms of uptake in cancer cells of rationally designed, covalently assembled nanoparticles, made of superparamagnetic iron oxide nanoparticles (SPIONs), fluorophores (doxorubicin or Nile Blue), polyethylene glycol (PEG) and folic acid (FA), referred hereinafter as SFP-FA. SFP-FA were characterized by DLS, zetametry and fluorescence spectroscopy. The SFP-FA uptake in cancer cells was monitored using fluorescence-based methods like fluorescence-assisted cell sorting, CLSM with single-photon and two-photon excitation. The SFP-FA endocytosis was also analyzed with electron microscopy approaches: TEM, HAADF-STEM and EELS. The SFP-FA have zeta potential below −6mW and stable hydrodynamic diameter close to 100nm in aqueous suspensions of pH range from 5 to 8. They contain ca. 109 PEG-FA, 480 PEG-OCH3 and 22–27 fluorophore molecules per SPION. The fluorophores protected under the PEG shell allows a reliable detection of intracellular NPs. SFP-FA readily enter into all the cancer cell lines studied and accumulate in lysosomes, mostly via clathrin-dependent endocytosis, whatever the FR status on the cells. The present study highlights the advantages of rational design of nanosystems as well as the possible involvement of direct molecular interactions of PEG and FA with cellular membranes, not limited to FA-FR recognition, in the mechanisms of their endocytosis. Composition, magnetic and optical properties of the SFP-FA as well their ability to enter cancer cells are promising for their applications in cancer theranosis. Combination of complementary analytical approaches is relevant to understand the nanoparticles behavior in suspension and in contact with cells. [Display omitted] •Complementary analytical approaches applied to understand NP-cell interactions.•Rationally designed NPs, are stable and show high intracellular accumulation.•NP-cell interactions are not limited to folic acid-folatereceptor (FR) recognition.•Whatever FR status of cells, NPs undergo a clathrin-dependent endocytosis.