A targeted combinatorial therapy for Ewing's sarcoma.

Ewing's sarcoma (EwS) is the second most common bone cancer in children and adolescents. Current chemotherapy regimens are mainly ineffective in patients with relapsed disease and cause long-term effects in survivors. Therefore, we have developed a combinatorial therapy based on a novel drug candidate named ML111 that exhibits selective activity against EwS cells and synergizes with vincristine. To increase the aqueous solubility of hydrophobic ML111, polymeric nanoparticles (ML111-NP) were developed. In vitro data revealed that ML111-NP compromise viability of EwS cells without affecting non-malignant cells. Furthermore, ML111-NP exhibit strong synergistic effects in a combination with vincristine on EwS cells, while this drug pair exhibits antagonistic effects towards normal cells. Finally, animal studies validated that ML111-NP efficiently accumulate in orthotopic EwS xenografts after intravenous injection and provide superior therapeutic outcomes in a combination with vincristine without evident toxicity. These results support the potential of the ML111-based combinatorial therapy for EwS.

Dual-drug loaded micelle for combinatorial therapy targeting HIF and mTOR signaling pathways for ovarian cancer treatment.

Mutations in the tumor protein (TP53) and the mammalian target of rapamycin (mTOR) pathway have been elucidated as driver mutations in ovarian carcinomas that transform into an invasive phenotype under hypoxic conditions. Chetomin (CHE) targets the hypoxic pathway while Everolimus (EVR) acts on the mTOR pathway. Poor aqueous solubilities of both compounds limit their clinical applications. Diblock copolymer nanoplatforms of methoxy poly(ethylene glycol)2000-block-poly (lactic acid)1800 (mPEG2000-b-PLA1800) and (mPEG4000-b-PLA2200) were used to formulate individual and dual drug loaded micelles (DDM) using the solvent evaporation method. The CHE micelles (CHE-M) had a size of 21 nm with CHE loading of 0.5 mg/mL while the EVR micelles (EVR-M) and the DDM had a size around 35 and 39 nm, respectively, with EVR loading up to 2.3 mg/mL. The anti-proliferative effects of these micelles have been tested in vitro in three ovarian cell lines (ES2, OVCAR3 and TOV21G) with the DDM exhibiting a strong synergistic anti-proliferative effect in the ES2 and the TOV21G cells. The DDM were able to significantly induce tumor regression in ES2 ovarian xenograft mouse models by inhibiting angiogenesis and inducing apoptosis when compared to the individual micelles. The inhibition of hypoxia inducible factor (HIF) and the mTOR pathways has been elucidated using immunohistochemistry studies. In conclusion, we have developed a mPEG-b-PLA based micellar nanoplatform that could prevent drug resistance by delivering multiple drugs at therapeutically relevant concentrations for effectively treating ovarian carcinomas.