Therapeutic enhancement of vascular-targeted photodynamic therapy by inhibiting proteasomal function.

Vascular-targeted photodynamic therapy (vPDT) is a novel vascular targeting modality based on site-directed delivery of a photosensitizer to tumor vasculature, which induces reactive oxygen species (ROS)-mediated vascular effects upon light activation. To enhance the therapeutic outcome of vPDT, we combined proteasomal inhibitor bortezomib and vPDT using photosensitizer verteporfin in the present study. We found that bortezomib in combination with verteporfin-PDT induced more accumulation of ubiquitinated proteins and apoptosis in endothelial cells than each individual treatment.

Disparity between prostate tumor interior versus peripheral vasculature in response to verteporfin-mediated vascular-targeting therapy.

Photodynamic therapy (PDT) is a light-based cancer treatment modality. Here we employed both in vivo and ex vivo fluorescence imaging to visualize vascular response and tumor cell survival after verteporfin-mediated PDT designed to target tumor vasculature. EGFP-MatLyLu prostate tumor cells, transduced with EGFP using lentivirus vectors, were implanted in athymic nude mice.

Intravital microscopic analysis of vascular perfusion and macromolecule extravasation after photodynamic vascular targeting therapy.

Purpose: Photodynamic therapy (PDT), involving the combination of a photosensitizer and light, is being evaluated as a vascular disrupting therapy and drug delivery enhancement modality based on its effects on vascular perfusion and barrier function. Since tumor vasculature is the common route for the delivery of both blood and therapeutic agents, it is important to compare the effects of PDT on blood perfusion and substance transport.

Materials And Methods: Tumor blood cell velocity and the extravasation of high molecular weight dextran molecules were continuously monitored by intravital fluorescence microscopy for up to 60 min after PDT using three doses of verteporfin in the MatLyLu prostate tumor model.