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Pancreatic ductal adenocarcinoma (PDAC) is highly resistant to chemotherapy. It has been described as requiring elevated autophagy for growth and inhibiting autophagy has been proposed as a treatment strategy. To date, all preclinical reports and clinical trials investigating pharmacological inhibition of autophagy have used chloroquine or hydroxychloroquine, which interfere with lysosomal function and block autophagy at a late stage. Verteporfin is a newly discovered autophagy inhibitor that blocks autophagy at an early stage by inhibiting autophagosome formation. Here we report that PDAC cell lines show variable sensitivity to verteporfin in vitro, suggesting cell-line specific autophagy dependence. Using image-based and molecular analyses, we show that verteporfin inhibits autophagy stimulated by gemcitabine, the current standard treatment for PDAC. Pharmacokinetic and efficacy studies in a BxPC-3 xenograft mouse model demonstrated that verteporfin accumulated in tumors at autophagy-inhibiting levels and inhibited autophagy in vivo, but did not reduce tumor volume or increase survival as a single agent. In combination with gemcitabine verteporfin moderately reduced tumor growth and enhanced survival compared to gemcitabine alone. While our results do not uphold the premise that autophagy inhibition might be widely effective against PDAC as a single-modality treatment, they do support autophagy inhibition as an approach to sensitize PDAC to gemcitabine.

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Ovarian cancer is the most common gynecological cancer diagnosed in Western countries. Detection of micrometastases at an early stage of the disease could lead to a cure rate of 90% by limiting the spread of the disease outside the ovaries. In this article, hypericin (Hy), a hydrophobic photosensitizer used for the photodynamic diagnosis (PD) of ovarian cancer, was efficiently incorporated into a core of micelles made from methoxy-poly(ethylene glycol) and hexyl-substituted poly(lactides) copolymers. The fate of these micelles following intravenous injection was studied in vivo in two ovarian tumor-bearing animal models. In the chick embryo chorioallantoic membrane model, 17 times more Hy accumulated in tumor nodules when Hy was delivered with micelles than when Hy was delivered as an ethanol solution. Studies of the biodistribution of Hy in Fisher rats revealed escape of these nanosized micelles (<32 nm) from the mononuclear phagocyte system. Hy-loaded micelles showed maximal accumulation in tumors and demonstrated the best tumor/muscle contrast visible 3 h after injection in the rat model. The rapid and highly selective accumulation of Hy in tumors that we demonstrated in this study suggests that these micelle formulations could be used for the PD of ovarian cancer in the future.

The objective of this study was to evaluate the tolerability, to establish a dosing regimen, and to evaluate the efficacy of intravesical docetaxel (DTX) formulations in a mouse model of bladder cancer. DTX in commercial formulation (Taxotere, DTX in Tween 80) or loaded in hyperbranched polyglycerols (HPGs) was evaluated. The synthesis and characterization of HPGs with hydrophobic cores and derivatized with methoxy poly(ethylene glycol) in the shell and further functionalized with amine groups (HPG-C(8/10)-MePEG and HPG-C(8/10)-MePEG-NH(2)) is described. Intravesical DTX in either commercial or HPGs formulations (up to 1.0 mg/mL) was instilled in mice with orthotopic bladder cancer xenografts and was well tolerated with no apparent signs of local or systemic toxicities. Furthermore, a single dose of intravesical DTX (0.5 mg/mL) loaded in HPGs was significantly more effective in reducing the tumor growth in an orthotopic model of bladder cancer than the commercial formulation of Taxotere. In addition, DTX-loaded HPG-C(8/10)-MePEG-NH(2) was found to be more effective at lower instillation dose than DTX (0.2 mg/mL)-loaded HPG-C(8/10)-MePEG. Overall, our data show promising antitumor efficacy and safety in a recently validated orthotopic model of bladder cancer. Further research is warranted to evaluate its safety and efficacy in early phase clinical trials in patients refractory to standard intravesical therapy.

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Rodent and CAM models led to the same conclusion regarding the benefits of nanoencapsulation to improve selective accumulation of drug in ovarian micrometastases.