Internalization and Intracellular Trafficking of Poly(propylene imine) Glycodendrimers with Maltose Shell in Melanoma Cells

Abstract

The diagnosis and treatment of malignant melanoma by means of the formulation of active principles with dendrimeric nanoparticles is an area of great current interest. The identification and understanding of molecular mechanisms which ensure the integration of particular dendrimeric nanostructures in tumor cellular environment can provide valuable guidance in their coupling strategies with antitumor or diagnostic agents. Two structurally distinct maltose-shell modified 5th generation (G5) poly(propylene imine) (PPI) glycodendrimers fluorescently labeled, (a) with open maltose shell, cationic charged G5-PPI-OS and (b) with dense maltose shell and nearly neutral G5-PPI-DS, were tested in relation with several melanoma cell lines. We found that three melanoma cell lines internalize G5-PPI-DS structure more efficiently than non tumoral HEK297T cells. Furthermore, the internalization pathways of G5-PPI-OS and G5-PPI-DS are characteristic for each tumor cell phenotype and include more than one mechanism. As a general trend, large amounts of both G5-PPI-OS and G5-PPI-DS are internalized on cholesterol-dependent pathway in MJS primary melanoma cells and on non conventional pathways in SK28 metastatic melanoma cells. G5-PPI-OS, temporarily retained at plasma membrane in both cell lines, is internalized slower in metastatic than in primary phenotype. Unlike G5-PPI-OS, G5-PPI-DS is immediately endocytosed in both cell lines. The unconventional internalization pathway and trafficking, exclusively used by G5-PPI-DS in metastatic cells, is described at molecular level. The decay kinetics of fluorescent labeled G5-PPI-OS and G5-PPI-DS is distinct in the two cellular phenotypes. Both cationic and neutral maltose G5-PPI glycodendrimeric structures represent molecules based on which designing of new formulations for therapy or/and diagnosis of melanoma can be further developed.

Effect of Poly(propylene imine) Glycodendrimers on β-Amyloid Aggregation in Vitro and in APP/PS1 Transgenic Mice, as a Model of Brain Amyloid Deposition and Alzheimer’s Disease

“…Furthermore, this observation is in agreement with a previous cellular uptake study in which nonendocytotic and endocytotic uptake of cationic and neutral PPI maltose dendrimers was identified in normal and cancer melanoma cell lines. 38 The effect of maltose-decorated dendrimers on Aβ(1−42) toxicity, administered to cell cultures, shows a nontoxic profile in comparison to previous data, where only G4mDS at area with respect to the total cortex area, was higher in G4mOS-treated APP/PS1 mice compared with the control group of APP/PS1 mice. (E) Representative FTIR microscope image of amida I absorbance in Aβ plaques of APP/PS1 mice.…”

Cytotoxicity and intracellular fate of PLGA and chitosan‐coated PLGA nanoparticles in Madin–Darby bovine kidney (MDBK) and human colorectal adenocarcinoma (Colo 205) cells

“…Then, cells were fixed with 4% paraformaldehyde for 10 min and permeabilized using 0.2% Triton X‐100. Subsequently, the immunofluorescence protocol was applied, as previously described by other studies . Briefly, unspecific binding sites were blocked by incubation with 0.5% BSA for 30 min followed by cell incubation either with goat anti‐CNX primary antibody, diluted 1:500, for endoplasmic reticulum (ER) or rabbit anti‐Rab 5 primary antibody, diluted 1:100, for early endosomes.…”

“…Subsequently, the immunofluorescence protocol was applied, as previously described by other studies. 15,26,27 Briefly, unspecific binding sites were blocked by incubation with 0.5% BSA for 30 min followed by cell incubation either with goat anti-CNX primary antibody, diluted 1:500, for endoplasmic reticulum (ER) or rabbit anti-Rab 5 primary antibody, diluted 1:100, for early endosomes. After three washings with PBS, cells were further incubated with secondary antibodies such as donkey anti-goat IgG and anti-rabbit IgG, respectively, conjugated to Alexa Fluor 594, and diluted (1:400).…”

Interaction study between maltose-modified PPI dendrimers and lipidic model membranes

“…Moreover, a fundamental understanding of their molecular interaction properties against a biological cell membrane and model lipid membranes is mostly unknown. Efforts have been made to evaluate the complex cellular uptake in normal and cancer melanoma cells [17]. In this context, open and dense shell PPI glycodendrimers (Fig.…”