title: Photoactivation of lysosomally sequestered sunitinib after angiostatic treatment causes vascular occlusion and enhances tumor growth inhibition.
abstract: The angiogenesis inhibitor sunitinib is a tyrosine kinase inhibitor that acts mainly on the VEGF and PDGF pathways. We have previously shown that sunitinib is sequestered in the lysosomes of exposed tumor and endothelial cells. This phenomenon is part of the drug-induced resistance observed in the clinic. Here, we demonstrate that when exposed to light, sequestered sunitinib causes immediate destruction of the lysosomes, resulting in the release of sunitinib and cell death. We hypothesized that this photoactivation of sunitinib could be used as a vaso-occlusive vascular-targeting approach to treating cancer. Spectral properties of sunitinib and its lysosomal accumulation were measured in vitro. The human A2780 ovarian carcinoma transplanted onto the chicken chorioallantoic membrane (CAM) and the Colo-26 colorectal carcinoma model in Balb/c mice were used to test the effects of administrating sunitinib and subsequently exposing tumor tissue to light. Tumors were subsequently resected and subject to immunohistochemical analysis. In A2780 ovarian carcinoma tumors, treatment with sunitinib+light resulted in immediate specific angio-occlusion, leading to a necrotic tumor mass 24 h after treatment. Tumor growth was inhibited by 70% as compared with the control group (**P<0.0001). Similar observations were made in the Colo-26 colorectal carcinoma, where light exposure of the sunitinib-treated mice inhibited tumor growth by 50% as compared with the control and by 25% as compared with sunitinib-only-treated tumors (N≥4; P=0.0002). Histology revealed that photoactivation of sunitinib resulted in a change in tumor vessel architecture. The current results suggest that the spectral properties of sunitinib can be exploited for application against certain cancer indications.
authors: Institute of Chemical Sciences and Engineering, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland.
authors: P
authors: P
authors: Nowak-Sliwinska
authors: 1] Institute of Chemical Sciences and Engineering, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland [2] Department of Medical Oncology, Angiogenesis Laboratory, VU University Medical Center, Amsterdam, The Netherlands.
authors: A
authors: A
authors: Weiss
authors: Department of Medical Oncology, Angiogenesis Laboratory, VU University Medical Center, Amsterdam, The Netherlands.
authors: J R
authors: JR
authors: van Beijnum
authors: Department of Medical Oncology, Angiogenesis Laboratory, VU University Medical Center, Amsterdam, The Netherlands.
authors: T J
authors: TJ
authors: Wong
authors: Institute of Bioengineering, School of Life Sciences, SV IBI LLCB, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland.
authors: W W
authors: WW
authors: Kilarski
authors: Department of Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland.
authors: G
authors: G
authors: Szewczyk
authors: Department of Medical Oncology, Angiogenesis Laboratory, VU University Medical Center, Amsterdam, The Netherlands.
authors: H M W
authors: HM
authors: Verheul
authors: Department of Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland.
authors: T
authors: T
authors: Sarna
authors: Institute of Chemical Sciences and Engineering, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland.
authors: H
authors: H
authors: van den Bergh
authors: Department of Medical Oncology, Angiogenesis Laboratory, VU University Medical Center, Amsterdam, The Netherlands.
authors: A W
authors: AW
authors: Griffioen
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D002645:Chickens; D015179:Colorectal Neoplasms / Q000188:drug therapy / Q000378:metabolism / Q000628:therapy; D005260:Female; D061307:Human Umbilical Vein Endothelial Cells; D006801:Humans; D007150:Immunohistochemistry; D007211:Indoles / Q000378:metabolism* / Q000627:therapeutic use*; D008247:Lysosomes / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D010051:Ovarian Neoplasms / Q000188:drug therapy / Q000378:metabolism / Q000628:therapy; D010789:Phototherapy; D011758:Pyrroles / Q000378:metabolism* / Q000627:therapeutic use*; D000077210:Sunitinib
chemical_list: D007211:Indoles; D011758:Pyrroles; D000077210:Sunitinib