Surface-modified nanoparticle transport evaluated in a multistage model of ovarian cancer.

Abstract

e18057 Background: A novel multi-stage model composed of ovarian cancer (SKOV-3) and fibroblast (MRC-5) cells was developed to provide a physiologically relevant in vitro platform to assess nanoparticle (NP) transport and aid in the development of more targeted clinical therapies. This multicellular ovarian tumor spheroid model is customized to the stages of ovarian cancer progression. The model leverages knowledge of these distinct stages in vivo to simulate their respective microenvironment, and thus provide a more accurate platform for evaluation of nanoparticle transport and drug delivery into ovarian tumor tissue. We hypothesized that alterations to the tumor microenvironment (TME) along with inclusion of a peptide-based scaffold (Puramatrix, PMX) to represent the site of metastasis, would lead to enhanced cell growth, migration and altered NP transport, which may be more indicative of the challenging transport conditions encountered in clinical ovarian cancer. Methods: In order to validate the in vitro model, tumor spheroid growth and invasion were evaluated while exposed to stromal cell activation and tissue hypoxia. MRC-5 activation was achieved via the TGF-ß1 mediated pathway, while tissue hypoxia was induced via incubation at 5% oxygen. PEG and MPG surface-modified NP transport was assessed in both stages of the model via confocal microscopy. Results: Consistent with in vivo observations in the ascites and site of distal metastasis, spheroids exposed to an activated stromal microenvironment were denser, more contractile and more invasive than their unactivated counterparts (p < 0.05). Additionally, hypoxic conditions, like those observed in the low pH environment of the ascites, resulted in negative spheroid radial growth over 5 days, compared to an increase for those cultured in normoxic conditions (p < 0.005). MPG-modified NPs exhibited superior tissue penetration relative to PEG-modified NPs in the ascites stage of the model (p < 0.05). Alternatively, PEG NPs enhanced penetration relative to MPG NPs when evaluated under metastatic conditions. In this case, NP transport was attenuated regardless of surface modification, due to the PMX-induced ECM reorganization. Conclusions: A novel multi-stage model, representative of ovarian cancer, was developed to evaluate NP transport in tumor tissue. We evaluated critical conditions in the microenvironment of ascites and metastasis and how these conditions may affect nanotherapy. Future studies will evaluate NP treatments by encapsulating a chemotherapeutic and measuring IC-50 values.