Improved anti-tumor efficacy of paclitaxel in combination with MicroRNA-125b-based tumor-associated macrophage repolarization in epithelial ovarian cancer.

In epithelial ovarian cancers, the presence of tumor-associated macrophages (TAMs) is well correlated with the poor disease outcomes. TAMs are know to suppress the immune system, induce pro-tumoral functions and inhibit anti-tumor responses associated with chemotherapy. In this study, we have evaluated the synergistic efficacy of TAM repolarization and intraperitoneal paclitaxel in epithelial ovarian cancers. We demonstrate that hyaluronic acid-based nanoparticles encapsulating miR-125b (HA-PEI-miR-125b) can specifically target TAMs in the peritoneal cavity of a syngeneic ID8-VEGF ovarian cancer mouse model and can repolarize macrophages to an immune-activating phenotype. These HA-PEI-miR-125b nanoparticles in combination with intraperitoneal paclitaxel can enhance the anti-tumor efficacy of paclitaxel during the later stages of disease progression as seen by the significant reduction in the ascitic fluid and peritoneal VEGF levels. Furthermore, these HA-PEI-miR-125b nanoparticles do not induce systemic toxicity and thus warrant a further evaluation in the clinical setting.

Inhibition of hexokinase-2 with targeted liposomal 3-bromopyruvate in an ovarian tumor spheroid model of aerobic glycolysis.

BACKGROUND: The objective of this study was to evaluate the expression levels of glycolytic markers, especially hexokinase-2 (HK2), using a three-dimensional multicellular spheroid model of human ovarian adenocarcinoma (SKOV-3) cells and to develop an epidermal growth factor receptor-targeted liposomal formulation for improving inhibition of HK2 and the cytotoxicity of 3-bromopyruvate (3-BPA). METHODS: Multicellular SKOV-3 tumor spheroids were developed using the hanging drop method and expression levels of glycolytic markers were examined. Non-targeted and epidermal growth factor receptor-targeted liposomal formulations of 3-BPA were formulated and characterized. Permeability and cellular uptake of the liposomal formulations in three-dimensional SKOV-3 spheroids was evaluated using confocal microscopy. The cytotoxicity and HK2 inhibition potential of solution form of 3-BPA was compared to the corresponding liposomal formulation by using cell proliferation and HK2 enzymatic assays. RESULTS: SKOV-3 spheroids were reproducibly developed using the 96-well hanging drop method, with an average size of 900 µm by day 5. HK2 enzyme activity levels under hypoxic conditions were found to be higher than under normoxic conditions (P<0.0001, Student's t-test, unpaired and two-tailed). Liposomal formulations (both non-targeted and targeted) of 3-BPA showed a more potent inhibitory effect (P<0.001, Student's t-test, unpaired and two-tailed) at a dose of 50 µM than the aqueous solution form at 3, 6, and 24 hours post administration. Similarly, the cytotoxic activity 3-BPA at various concentrations (10 µM-100 µM) showed that the liposomal formulations had an enhanced cytotoxic effect of 2-5-fold (P<0.0001, Student's t-test, unpaired and two-tailed) when compared to the aqueous solution form for both 10 µM and 25 µM concentrations. CONCLUSION: SKOV-3 spheroids developed by the hanging drop method can be used as a tumor aerobic glycolysis model for evaluation of therapies targeting the glycolytic pathway in cancer cells. Encapsulation of 3-BPA in a liposomal formulation improved permeability, HK2 inhibition, and cytotoxicity in the multicellular spheroid model.