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We report an efficient therapeutic modality for platinum resistant ovarian cancer based on siRNA-mediated suppression of a multifunctional DJ-1 protein that is responsible for the proliferation, growth, invasion, oxidative stress, and overall survival of various cancers. The developed therapeutic strategy can work alone or in concert with a low dose of the first line chemotherapeutic agent cisplatin, to elicit a maximal therapeutic response. To achieve an efficient DJ-1 knockdown, we constructed the polypropylenimine dendrimer-based nanoplatform targeted to LHRH receptors overexpressed on ovarian cancer cells. The quantitative PCR and Western immunoblotting analysis revealed that the delivered DJ-1 siRNA downregulated the expression of targeted mRNA and corresponding protein by more than 80% in various ovarian cancer cells. It was further demonstrated that siRNA-mediated DJ-1 suppression dramatically impaired proliferation, viability, and migration of the employed ovarian cancer cells. Finally, the combinatorial approach led to the most pronounced therapeutic response in all the studied cell lines, outperforming both siRNA-mediated DJ-1 knockdown and cisplatin treatment alone. It is noteworthy that the platinum-resistant cancer cells (A2780/CDDP) with the highest basal level of DJ-1 protein are most susceptible to the developed therapy and this susceptibility declines with decreasing basal levels of DJ-1. Finally, we interrogate the molecular underpinnings of the DJ-1 knockdown effects in the treatment of the ovarian cancer cells. By using various experimental techniques, it was revealed that DJ-1 depletion (1) decreases the activity of the Akt pathway, thereby reducing cellular proliferation and migration and increasing the antiproliferative effect of cisplatin on ovarian cancer cells; (2) enhances the activity of p53 tumor suppressor protein therefore restoring cell cycle arrest functionality and upregulating the Bax-caspase pathway, triggering cell death; and (3) weakens the cellular defense mechanisms against inherited oxidative stress thereby increasing toxic intracellular radicals and amplifying the reactive oxygen species created by the administration of cisplatin.

Nerve damage during surgery is a common morbidity experienced by patients that leaves them with chronic pain and/or loss of function. Currently, no clinically approved imaging technique exists to enhance nerve visualization in the operating room. Fluorescence image-guided surgery has gained in popularity and clinical acceptance over the past decade with a handful of imaging systems approved for clinical use. However, contrast agent development to complement these fluorescence-imaging systems has lagged behind with all currently approved fluorescent agents providing untargeted blood pool information. Nerve-specific fluorophores are known, however translations of these agents to the clinic has been complicated by their lipophilic nature, which necessitates specialized formulation strategies for successful systemic administration. To date the known nerve-specific fluorophores have only been demonstrated preclinically due to the necessity of a dimethyl sulfoxide containing formulation for solubilization. In the current study, a polymeric micellar (PM) formulation strategy was developed for a representative nerve-specific fluorophore from the distyrylbenzene family, BMB. The PM formulation strategy was able to solubilize BMB and demonstrated improved nerve-specific accumulation and fluorescence intensity when the same fluorophore dose was administered to mice utilizing the previous formulation strategy. The success of the PM formulation strategy will be important for moving toward clinical translation of these novel nerve-specific probes as it is nontoxic and biodegradable and has the potential to decrease the necessary dose for imaging while also improving the safety profile.

Angiogenesis is an essential process for disease progression in many solid tumors. There are several major cascade events in the angiogenic process that can be targeted to inhibit new blood vessel formation in the tumor tissue. The purpose of this work is to evaluate the inhibitory effect of paclitaxel (PTX) and rapamycin (RAP) as individual and in dual drug-loaded poly(ethylene glycol)-block-poly(d,l-lactic acid) (PEG-b-PLA) micelles on the angiogenic cascade processes of proliferation, migration, and tube formation. PEG-b-PLA PTX and/or RAP micelles were formed and characterized for size and drug loading. Sizes of individual and dual drug micelles were below 40 nm. PEG-b-PLA micelles significantly enhanced the aqueous solubility of PTX 1.80 mg/mL and RAP 1.60 mg/mL. The PTX-RAP dual drug PEG-b-PLA micelles were able to load PTX and RAP at 1.60 mg/mL for both drugs. Cell proliferation, apoptosis, tubule formation, and migration studies were performed in human umbilical vein endothelial cells (HUVEC). PTX and RAP in DMSO inhibited HUVEC proliferation with IC50 values of 0.82 ± 0.02 and 13 829 ± 681 nM, respectively, while the combination of both drugs in DMSO produced synergistic inhibition. PTX and RAP individual micelles had IC50 values of 6.3 ± 1.1 and 14 051 ± 821 nM, respectively. PTX and dual drug micelles had a synergistic inhibition effect on HUVEC proliferation through the induction of apoptosis via caspase 3/7 activity. In vitro tube formation assay demonstrated significant inhibition of tube formation upon treatment with dual drug micelles as compared to individual PTX or RAP micelles. Migration studies in HUVEC have shown that individual PTX micelles inhibited cell migration at 1 nM, while RAP micelles did not show any inhibitory effect on cell migration. Interestingly, the presence of RAP in the dual drug micelles was able to initiate the inhibition of the migration of HUVEC at 0.1 nM concentration of PTX. These results indicate that PTX-RAP dual drug micelles have antiangiogenic effects in vitro mediated through three major events in the angiogenic process and have strong potential for further development as antiangiogenic chemotherapy.

Poly(ethylene glycol)-block-poly(D,L-lactic acid) (PEG-b-PLA) micelles have a proven capacity for drug solubilization and have entered phase III clinical trials as a substitute for Cremophor EL in the delivery of paclitaxel in cancer therapy. PEG-b-PLA is less toxic than Cremophor EL, enabling a doubling of paclitaxel dose in clinical trials. We show that PEG-b-PLA micelles act as a 3-in-1 nanocontainer for paclitaxel, 17-allylamino-17-demethoxygeldanamycin (17-AAG), and rapamycin for multiple drug solubilization. 3-in-1 PEG-b-PLA micelles were ca. 40 nm in diameter; dissolved paclitaxel, 17-AAG, and rapamycin in water at 9.0 mg/mL; and were stable for 24 h at 25 °C. The half-life for in vitro drug release (t(1/2)) for 3-in-1 PEG-b-PLA micelles was 1-15 h under sink conditions and increased in the order of 17-AAG, paclitaxel, and rapamycin. The t(1/2) values correlated with log P(o/w) values, implicating a diffusion-controlled mechanism for drug release. The IC(50) value of 3-in-1 PEG-b-PLA micelles for MCF-7 and 4T1 breast cancer cell lines was 114 ± 10 and 25 ± 1 nM, respectively; combination index (CI) analysis showed that 3-in-1 PEG-b-PLA micelles exert strong synergy in MCF-7 and 4T1 breast cancer cell lines. Notably, concurrent intravenous (iv) injection of paclitaxel, 17-AAG, and rapamycin using 3-in-1 PEG-b-PLA micelles was well-tolerated by FVB albino mice. Collectively, these results suggest that PEG-b-PLA micelles carrying paclitaxel, 17-AAG, and rapamycin will provide a simple yet safe and efficacious 3-in-1 nanomedicine for cancer therapy.