Interferon-containing controlled-release polymers for localized cerebral immunotherapy

Preferential drug delivery to tumor cells than normal cells using a tunable niosome–chitosan double package nanodelivery system: a novel in vitro model

Background

We previously described the properties of a targeted drug delivery system (DDS) in a cell-free system. Here, in this comparative cell-based study (normal and tumor cells), we provide a quantitative analysis of the extracellular diffusion and intracellular localization of this DDS. This DDS consists of fluorescence-labeled paclitaxel encapsulated in non-ionic surfactant vesicles/niosomes embedded in a thermo-sensitive cross-linked chitosan hydrogel with an affinity for the MUC1 mucin surface antigen overexpressed on tumor cells, and designed for a sustained and controlled, localized delivery of embedded drugs. We evaluated DDS in our novel in vitro model using MatTek’ glass-bottom culture plates and compared human cancer cell lines (OV2008 epithelial origin carcinoma and U373 glioma, both overexpressing MUC1) with human normal epithelial control cell lines (IMMC3 and IOSE-121 using differential contrast and confocal microscopy.

Results

Tumor cells incubated in the presence of chitosan alone or DDS-containing chitosan–niosome–paclitaxel–BODIPY 564/570, showed a prominent granular accumulation on their surface when compared to the normal cells. Quantitation of gray value light intensity of the extracellular region of chitosan alone treated OV2008 and IOSE-121 controls done by analysis of multiple radial line segments, 4 µm each, using ImageJ software showed 2 times higher intensity around the OV2008 than around normal IOSE-121 controls (p < 0.05). In the DDS-treated OV2008 cells, extracellular fluorescence intensity measured at different diffusion distances outside of the cells, in three different zones showed the difference in means of fluorescence intensity in these zones (p < 0.05) with the highest level of fluorescence near the cell surface indicating a concentration gradient, most likely driven by the high affinity of chitosan to the MUC1 receptor. Also, as chitosan alone accumulated two times more along the edge of tumor cells compared to normal cells, we found intracellular fluorescence intensity quantified at time intervals to be also 2 times higher in OV2008 than in normal IMCC3 cells (p < 0.05).

Conclusion

Based on the observation of the DDS preferentially targeting tumor cells, there is a potential implication for the localized delivery of therapeutic drug doses to solid tumors or post-surgical solid tumors cavities containing residual tumor cells.

Advances in brain tumor surgery

Advances in the fields of molecular and translational research, oncology, and surgery have emboldened the medical community to believe that intrinsic brain tumors may be treatable. Intraoperative imaging and brain mapping allow operations adjacent to eloquent cortex and more radical resection of tumors with increased confidence and safety. Despite these advances, the infiltrating edge of a neoplasm and distant microscopic satellite lesions will never be amendable to a surgical cure. Indeed, it is continued research into the delivery of an efficacious chemobiologic agent that will eventually allows us to manage this primary cause of treatment failure.