title: Pegylated liposome-encapsulated doxorubicin and cisplatin enhance the effect of radiotherapy in a tumor xenograft model.
abstract: Concomitant chemotherapy and radiotherapy (CCRT) has recently been shown to improve treatment outcome in a range of solid tumors. Pegylated liposomes have the potential to target drugs directly to tumors and may increase the efficacy and reduce the toxicity of CCRT by selectively delivering radiosensitizing agents to tumor, as opposed to normal, tissues. In these studies, we have assessed CCRT using pegylated liposome encapsulated doxorubicin (PLED) and pegylated liposome encapsulated cisplatin (PLEC) against KB head and neck cancer xenograft tumors in nude mice. The addition of low-dose (2 mg/kg) PLED (P < 0.001) and PLEC (P < 0.001) significantly increased the effect of 4.5 Gy, but not 9 Gy, single-fraction radiotherapy (SFRT). Both PLED and PLEC were significantly more effective than their unencapsulated counterparts in increasing the effect of SFRT. In addition, PLED (P < 0.001) and PLEC (P < 0.05) significantly increased the effect of fractionated radiotherapy (9 Gy in 3 fractions) in two different dosing schedules (2 mg/kg single dose or three sequential doses of 0.67 mg/kg). Unencapsulated diethylenetriaminepentaacetic acid and pegylated liposomal diethylenetriaminepentaacetic acid were used as controls to test the effect of the liposome vehicle and showed no interaction with 4.5 Gy or 9 Gy SFRT (P > 0.1). CCRT was well-tolerated, with no evidence of increased local or systemic toxicity, as compared with radiotherapy alone. This study is the first to demonstrate the value of pegylated liposomes as vehicles for the delivery of radiosensitizing drugs in CCRT strategies.
authors.affiliation: Oncology Unit, Imperial College of Science, Technology and Medicine, Hammersmith Hospital, London, United Kingdom. Harrington.Kevin@mayo.edu
authors.forename: K J
authors.initials: KJ
authors.lastname: Harrington
authors.forename: G
authors.initials: G
authors.lastname: Rowlinson-Busza
authors.forename: K N
authors.initials: KN
authors.lastname: Syrigos
authors.forename: R G
authors.initials: RG
authors.lastname: Vile
authors.forename: P S
authors.initials: PS
authors.lastname: Uster
authors.forename: A M
authors.initials: AM
authors.lastname: Peters
authors.forename: J S
authors.initials: JS
authors.lastname: Stewart
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000008:administration & dosage* / Q000627:therapeutic use; D002945:Cisplatin / Q000008:administration & dosage* / Q000627:therapeutic use; D003131:Combined Modality Therapy; D004305:Dose-Response Relationship, Drug; D004307:Dose-Response Relationship, Radiation; D004317:Doxorubicin / Q000008:administration & dosage* / Q000627:therapeutic use; D006258:Head and Neck Neoplasms / Q000188:drug therapy* / Q000532:radiotherapy*; D006801:Humans; D008081:Liposomes / Q000737:chemistry*; D051379:Mice; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D011092:Polyethylene Glycols / Q000737:chemistry*; D011836:Radiation Tolerance / Q000187:drug effects*; D011838:Radiation-Sensitizing Agents / Q000008:administration & dosage* / Q000627:therapeutic use; D013997:Time Factors; D014407:Tumor Cells, Cultured
chemical_list: D000970:Antineoplastic Agents; D008081:Liposomes; D011838:Radiation-Sensitizing Agents; D011092:Polyethylene Glycols; D004317:Doxorubicin; D002945:Cisplatin