Caveolin-Mediated Internalization of Fmoc-FF Nanogels in Breast Cancer Cell Lines

Abstract

Introduction: Hydrogel nanoparticles, also known as nanogels (NGs), have been recently proposed as alternative supramolecular vehicles for the delivery of biologically relevant molecules like anticancer drugs and contrast agents. The inner compartment of peptide based NGs can be opportunely modified according to the chemical features of the cargo, thus improving its loading and release. A full understanding of the intracellular mechanism involved in nanogel uptake by cancer cells and tissues would further contribute to the potential diagnostic and clinical applications of these nanocarriers, allowing the fine tuning of their selectivity, potency, and activity. The structural characterization of nanogels were assessed by Dynamic Light Scattering (DLS) and Nanoparticles Tracking Analysis (NTA) analysis. Cells viability of Fmoc-FF nanogels was evaluated by MTT assay on six breast cancer cell lines at different incubation times (24, 48, and 72 h) and peptide concentrations (in the range 6.25 × 10−4 ÷ 5·10−3 × wt%). The cell cycle and mechanisms involved in Fmoc-FF nanogels intracellular uptake were evaluated using flow cytometry and confocal analysis, respectively. Fmoc-FF nanogels, endowed with a diameter of ~130 nm and a zeta potential of ~−20.0/−25.0 mV, enter cancer cells via caveolae, mostly those responsible for albumin uptake. The specificity of the machinery used by Fmoc-FF nanogels confers a selectivity toward cancer cell lines overexpressing the protein caveolin1 and efficiently performing caveolae-mediated endocytosis.

Ultrashort Cationic Peptide Fmoc-FFK as Hydrogel Building Block for Potential Biomedical Applications

“…As previously observed for Fmoc-FF hydrogels, a maximum toxicity was reached after 24 h (Figure 6), while the cell survival percentage had increased at the subsequent observation times [47]. This effect may be ascribed to a temporary cycle arrest at the S phase, followed by a complete recovery of the cells (negligible or no toxicity compared to the control for all the explored ratios) after 48 and 72 h (Figure 6).…”

Fmoc-FF hydrogels and nanogels for improved and selective delivery of dexamethasone in leukemic cells and diagnostic applications

“…DOX loaded HGs and NGs exhibited both a different internalization mechanism and an intracellular distribution in comparison to the free drug 27 . Moreover, we also observed a selectivity of Fmoc-FF NGs towards cancer cell lines overexpressing the protein caveolin-1, such as MDA-MB-231 cells 28 .…”

“…Moreover, Chandran et al demonstrated that their PLGA polymer–protein core–shell formulation of nanoparticles, loaded with a mixture of everolimus, sorafenib, and inhibitors of mTOR, MAPK, and STAT5, produced a drastic synergistic lethality against leukemic cells, without affecting the viability of normal blood cells 49 . We previously demonstrated that Fmoc-FF NGs can be passively internalized by breast cancer cells through a caveolin-mediated mechanism 28 . Overexpression of caveolin-1 has been often seen as a distinctive marker for different leukemic subtypes 50 , 51 .…”

“…Passive targeting, on the other hand, is facilitated by some of the distinctive features of the tumour environment when compared to healthy tissue, like its propension to better absorb circulating nanoparticles 44 , 56 , 57 . Moreover, different types of leukemic cell types overexpress caveolin-1, previously identified as the main entrance gate for Fmoc-FF nanoparticles in cancer cells 28 , 52 , 53 making them sensibly more prone to endocite NPs. Given that, data obtained with Fmoc-FF nanogels, albeit preliminary, suggest a possible use of these nanocarriers to passively target leukemic cells over healthy PBMCs with a good specificity in the bloodstream.…”

Advances in Peptide-Decorated Targeted Drug Delivery: Exploring Therapeutic Potential and Nanocarrier Strategies

“…These nanogels are loaded with peptides that are targeted against skin infections caused by Staphylococcus aureus in the wounds, and their efficacy was also evaluated . Fmoc-FF, known to form self-assembling β-sheets, is a low molecular weight hydrogelator that forms hydrogels at physiological pH and was evaluated on breast cancer cells . Aromatic groups, when attached to the N-terminus of the short peptides, have the ability to form supramolecular hydrogels that can be self-assembled to trap water molecules that resemble the extracellular matrix of cells.…”