Heat-activated thermosensitive liposomal cisplatin (HTLC) results in effective growth delay of cervical carcinoma in mice.
Cisplatin (CDDP) has been identified as the primary chemotherapeutic agent for the treatment of cervical cancer, but dose limiting toxicity is a key issue associated with its clinical application. A suite of liposome formulations of CDDP has been developed in efforts to reduce systemic toxicity, but their therapeutic advantage over the free drug has been modest due to insufficient drug release at the tumor site. This report describes the development of a novel heat-activated thermosensitive liposome formulation containing CDDP (HTLC) designed to release approximately 90% of the loaded drug in less than 5min under mild heating conditions (42°C). Physico-chemical characteristics of HTLC were assessed in terms of gel to liquid crystalline phase transition temperature (Tm), drug loading efficiency, particle size, and stability. The pharmacokinetic profile and biodistribution of HTLC in non-tumor-bearing mice were evaluated over a 24h period. A sophisticated spatio-temporal elucidation of HTLC release in tumor-bearing mice was achieved by way of real-time monitoring using a magnetic resonance (MR) imaging protocol, wherein a custom-built laser-based conformal heat source was applied at the tumor volume to trigger the release of HTLC co-encapsulated with the MR contrast agent gadoteridol (Gd-HP-DO3A). MR thermometry (MRT) demonstrated that a relatively uniform temperature distribution was achieved in the tumor volume using the external laser-based heating setup. In mice bearing subcutaneously-implanted ME-180 cervical tumors, the combination of HTLC and heat resulted in a 2-fold increase in tumor drug levels at 1h post-administration compared to HTLC without heating. Furthermore, the overall tumor accumulation levels for the HTLC groups (with and without heat) at 1h post-injection were significantly higher than the corresponding free CDDP group. This translated into a significant improvement in therapeutic efficacy evaluated as tumor growth delay (p<0.05) for the heated HTLC treatment group compared to the unheated HTLC, heated or unheated free CDDP, and saline groups. Overall, findings from this study demonstrate that a heat-activated, triggered release formulation of CDDP results in a significant enhancement in the therapeutic index of this drug.
Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON M5S 3M2, Canada.
Yannan N
YN
Dou
STTARR Innovation Center, University Health Network, Toronto, ON M5G 1L7, Canada; Techna Institute, Radiation Medicine Program, Princess Margaret Cancer Center, University Health Network, Toronto, ON M5G 1L7, Canada.
Jinzi
J
Zheng
STTARR Innovation Center, University Health Network, Toronto, ON M5G 1L7, Canada; Techna Institute, Radiation Medicine Program, Princess Margaret Cancer Center, University Health Network, Toronto, ON M5G 1L7, Canada.
Warren D
WD
Foltz
Techna Institute, Radiation Medicine Program, Princess Margaret Cancer Center, University Health Network, Toronto, ON M5G 1L7, Canada.
Robert
R
Weersink
Ontario Cancer Institute, University Health Network, Toronto, ON M5G 2M9, Canada.
Naz
N
Chaudary
STTARR Innovation Center, University Health Network, Toronto, ON M5G 1L7, Canada; Techna Institute, Radiation Medicine Program, Princess Margaret Cancer Center, University Health Network, Toronto, ON M5G 1L7, Canada; Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 2M9, Canada; Department of Radiation Oncology, University of Toronto, Toronto, ON M5G 2M9, Canada; Institute of Biomaterials & Biomedical Engineering, University of Toronto, Toronto, ON M5S 1A1, Canada. Electronic address: david.jaffray@rmp.uhn.on.ca.
David A
DA
Jaffray
Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON M5S 3M2, Canada; STTARR Innovation Center, University Health Network, Toronto, ON M5G 1L7, Canada. Electronic address: cj.allen@utoronto.ca.
Christine
C
Allen
D000818:Animals; D000970:Antineoplastic Agents / Q000008:administration & dosage* / Q000493:pharmacokinetics; D045744:Cell Line, Tumor; D002945:Cisplatin / Q000008:administration & dosage* / Q000493:pharmacokinetics; D003131:Combined Modality Therapy; D005260:Female; D006358:Hot Temperature; D006801:Humans; D006979:Hyperthermia, Induced; D007834:Lasers; D008081:Liposomes; D051379:Mice; D016513:Mice, SCID; D014018:Tissue Distribution; D047368:Tumor Burden / Q000187:drug effects / Q000528:radiation effects; D002583:Uterine Cervical Neoplasms / Q000473:pathology / Q000628:therapy*; D023041:Xenograft Model Antitumor Assays
D000970:Antineoplastic Agents; D008081:Liposomes; D002945:Cisplatin
Cervical cancer; Cisplatin (CDDP); Gadoteridol (ProHance® Gd-HP-DO3A); Laser heating; Magnetic resonance (MR) imaging; Thermosensitive liposome