title: Photosensitizing effects of m-tetrahydroxyphenylchlorin on human tumor xenografts: correlation with sensitizer uptake, tumor doubling time and tumor histology.
abstract: The photodynamic effects of m-tetrahydroxyphenylchlorin (mTHPC) were assessed on human malignant mesothelioma, squamous cell carcinoma and adenocarcinoma xenografts grown in nude mice and were correlated with mTHPC uptake, histology and doubling time of the tumors. Non-thermal laser light was delivered to the tumor as surface radiation 4 days after intraperitoneal administration of 0.1 and 0.3 mg mTHPC/kg body weight, respectively. The extent of tumor necrosis was measured by histomorphometry. The mTHPC concentration in non-irradiated tumors was assessed by high-performance liquid chromatography (HPLC). The tumors were graded according to their doubling time and their vascular architecture as assessed by histology. The 0.1 mg/kg dose of mTHPC resulted in an equal uptake for all 3 tumor types but revealed a larger extent of photosensitized necrosis for adenocarcinoma, which displayed a delicate tumor stroma with numerous small capillary vessels, than for mesothelioma and squamous cell carcinoma, which were both poor in stroma and vessels. The 0.3 mg/kg dose of mTHPC resulted in a 2-fold higher tumor uptake for all 3 tumor types and in a larger extent of necrosis for mesothelioma and squamous cell carcinoma, but not for adenocarcinoma xenografts, compared with the lower drug dose. Our results demonstrate that different tumor xenografts respond differently to mTHPC-PDT for a given drug-light condition. In this setting, the photosensitizing effect was more closely related to the vascular architecture of the tumors than to the sensitizer uptake and doubling time of the different tumors
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, University of Bern, Switzerland.
authors.forename: H B
authors.initials: HB
authors.lastname: Ris
authors.forename: Q
authors.initials: Q
authors.lastname: Li
authors.forename: T
authors.initials: T
authors.lastname: Krueger
authors.forename: C K
authors.initials: CK
authors.lastname: Lim
authors.forename: B
authors.initials: B
authors.lastname: Reynolds
authors.forename: U
authors.initials: U
authors.lastname: Althaus
authors.forename: H J
authors.initials: HJ
authors.lastname: Altermatt
mesh_terms: D000230:Adenocarcinoma / Q000188:drug therapy; D000818:Animals; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy; D005260:Female; D006801:Humans; D008652:Mesoporphyrins / Q000493:pharmacokinetics / Q000627:therapeutic use*; D008654:Mesothelioma / Q000188:drug therapy; D051379:Mice; D008819:Mice, Nude; D009336:Necrosis; D009368:Neoplasm Transplantation; D009374:Neoplasms, Experimental / Q000188:drug therapy* / Q000473:pathology; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000627:therapeutic use*; D014183:Transplantation, Heterologous
chemical_list: D008652:Mesoporphyrins; D017319:Photosensitizing Agents; C072269:temoporfin