Monday, February 16, 2015

mPEG-PLA nanoparticles used as part of photo-triggered tumor treatment

PolySciTech ( provides a wide array of mPEG-PLA diblock copolymers for use in generating nanoparticles to improve drug delivery. Recently these types of polymers were used to improve uptake of paclitaxel in tumor-bearing mouse model. Read more: Araki, Tomoya, Ken-ichi Ogawara, Haruka Suzuki, Rie Kawai, Taka-ichi Watanabe, Tsutomu Ono, and Kazutaka Higaki. "Augmented EPR effect by photo-triggered tumor vascular treatment improved therapeutic efficacy of liposomal paclitaxel in mice bearing tumors with low permeable vasculature." Journal of Controlled Release 200 (2015): 106-114.

“Abstract: The effects of photo-triggered tumor vascular treatment (PVT) on the structural and functional properties of tumor vasculature were assessed in Colon-26 (C26) and B16/BL6 (B16) tumor-bearing mice. Furthermore, anti-tumor efficacy of subsequently injected PEG liposomal paclitaxel (PL-PTX) was also evaluated. As a photosensitizer, a hydrophobic porphyrin derivative was used and formulated in polymeric nanoparticle composed of polyethylene glycol-block-polylactic acid to avoid its non-specific in vivo disposition. In the mice bearing C26 with high permeable vasculature, the prominent anti-tumor activity was confirmed by PVT alone, but the subsequently injected PL-PTX did not show any additive effect. PVT itself initially induced apoptotic cell death of tumor vascular endothelial cells and platelet aggregation, which would have subsequently induced apoptosis of C26 tumor cells surrounding the vasculature. On the other hand, in the mice bearing B16 with low permeable vasculature, PVT enhanced the anti-tumor activity of subsequently injected PL-PTX, which would be attributed to the tumor disposition amount and area of PEG liposomes enhanced by PVT. These results clearly indicated that the treatment would have made it possible to provide more efficient extravasation of PL-PTX, leading to its more potent anti-tumor effect. Keywords: Vascular permeability; Photodynamic treatment; Endothelial cell; Liposome; Cancer chemotherapy”

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