Description
Photochlor, also known as HTTP, is a lipophilic, second-generation, chlorin-based photosensitizer. HPPH is a chlorin that acts as a photosensitizer in photodynamic therapy (PDT) when stimulated with light at 655 nm. When administered systemically, HPPH accumulates in tumor cells and, when stimulated with light in the presence of oxygen, reactive oxygen species (ROS) are generated, leading to necrosis within the tumor. HPPH, at a dose of 0.5 mg/kg, increases survival in a nude rat model of glioma. It works synergistically with gemcitabine in several pancreatic cancer cell lines to induce cell death.
Uses
Photochlor is an anticancer photodynamic therapy drug that triggers multiple drug release and tumor killing cells in mouse breast cancer xenograft. Also functions as a photochlor-mediated photodynamic therapy for non-small cellular lung cancer treatment in murine model.
in vivo
Tumors are treated with an immune-enhancing PDT regimen followed by a tumor-controlling PDT regimen can leads to enhancement of anti-tumor immunity, while retaining effective control of primary tumor growth. To test this hypothesis, a combination treatment regimen is devised in which Colo26-HA tumor-bearing BALB/c mice are treated with a HPPH-PDT regimen known to lead to enhanced anti-tumor immunity (0.4 μmoles/kg HPPH followed 18 h later by illumination with 665 nm light for a total dose of 48 J/cm2). Following illumination, mice are rested for 9 days; on the ninth day, mice are injected with HPPH. On day 10 following the first treatment, tumors are treated with a tumor control treatment regimen (illumination with 665 nm light for a total dose of 132 J/cm2 given)[2].
References
[1] DENNIS E.J.G.J. DOLMANS Rakesh K J Dai Fukumura. Photodynamic therapy for cancer[J]. Nature Reviews Cancer, 2003, 3 5: 380-387. DOI:
10.1038/nrc1071[2] JEFFREY LOBEL MD. 2-[1-hexyloxyethyl]-2-devinyl pyropheophorbide-a (HPPH) in a nude rat glioma model: Implications for photodynamic therapy[J]. Lasers in Surgery and Medicine, 2001, 29 5: 397-405. DOI:
10.1002/lsm.10001[3] MD G S, PHD Emmanuel C G M Marlys A Anderson BS, MPH, et al. Synergistic effects of photodynamic therapy with HPPH and gemcitabine in pancreatic cancer cell lines[J]. Lasers in Surgery and Medicine, 2012, 44 9: 755-761. DOI:
10.1002/lsm.22073
