Flow cytometry evidence of human granulocytes interaction with polyhedral oligomeric silsesquioxanes: effect of nanoparticle charge

Neutrophil and Nanoparticles Delivery to Tumor: Is It Going to Carry That Weight?

The application of cell carriers for transporting nanodrugs to the tumor draws much attention as the alternative to the passive drug delivery. In this concept, the neutrophil (NΦ) is of special interest as this cell is able to uptake nanoparticles (NPs) and cross the vascular barrier in response to tumor signaling. There is a growing body of literature describing NP-NΦ interactions in vitro and in vivo that demonstrates the opportunity of using these cells to improve the efficacy of cancer therapy. However, a number of conceptual and technical issues need to be resolved for translating the technology into clinics. The current review summarizes the recent advances and challenges associated with NP-NΦ interactions, with the special focus on the complex interplay between the NP internalization pathways and the modulation of NΦ activity, and its potential consequences for nanodrug delivery.

Verteporfin based silica nanoparticle for in vitro selective inhibition of human highly invasive melanoma cell proliferation

Photodinamic therapy (PDT) has gained an increasing interest as a new tool to treat skin cancers such as melanoma. This clinical approach take advantage from the combination of a photosensitizer and a specific light wavelength able to induce singlet oxygen production. Mesoporous silica nanoparticles (MSNs) have been widely investigated as drug nanocarriers as their structure and morphology could be customized to produce suitable nanoplatforms enabling high cargo capacity. In the present study MSNs were successfully conjugated with the second generation photosensitizer verteporfin and the resulting nanoplatform (Ver-MSNs) was tested in an in vitro PDT model as a potential tool for melanoma treatment. Ver-MSNs based PDT did not affect cell proliferation of neither a normal human keratinocyte cell line (HaCaT) or a low mestastatic melanoma cell line (A375P). On the other hand Ver-MSNs based PDT deeply affect the highly invasive SK-MEL-28 melanoma cell line behavior, as testified by the strong reduction in cell proliferation along with the dramatic change in cellular morphology, through a nanoparticle internalization dependent mechanism. In fact, experiments performed in the presence of endocytosis inhibitors (chlorpromazine and amiloride) resulted in an attenuation of Ver-MSNs based PDT induced cell death, along with a recover in cellular morphology. MSN doped with verteporfin could thus represent a promising and useful tool for PDT treatment of highly invasive melanoma.

Proper design of silica nanoparticles combines high brightness, lack of cytotoxicity and efficient cell endocytosis

Silica-based luminescent nanoparticles (SiNPs) show promising prospects in nanomedicine in light of their chemical properties and versatility. In this study, we have characterized silica core-PEG shell SiNPs derivatized with PEG moieties (NP-PEG), with external amino- (NP-PEG-amino) or carboxy-groups (NP-PEG-carbo), both in cell cultures as well as in animal models. By using different techniques, we could demonstrate that these SiNPs were safe and did not exhibit appreciable cytotoxicity in different relevant cell models, of normal or cancer cell types, growing either in suspension (JVM-2 leukemic cell line and primary normal peripheral blood mononuclear cells) or in adherence (human hepatocarcinoma Huh7 and umbilical vein endothelial cells). Moreover, by multiparametric flow cytometry, we could demonstrate that the highest efficiency of cell uptake and entry was observed with NP-PEG-amino, with a stable persistence of the fluorescence signal associated with SiNPs in the loaded cell populations both in vitro and in vivo settings suggesting this as an innovative method for cell traceability and detection in whole organisms. Finally, experiments performed with the endocytosis inhibitor Genistein clearly suggested the involvement of a caveolae-mediated pathway in SiNP endocytosis. Overall, these data support the safe use of these SiNPs for diagnostic and therapeutic applications.