Comparative positron-emission tomography (PET) imaging and phototherapeutic potential of 124I- labeled methyl- 3-(1'-iodobenzyloxyethyl)pyropheophorbide-a vs the corresponding glucose and galactose conjugates.
In our present study, 3-(1(')-m-iodobenzyloxyethyl)pyropheophorbide-a methyl ester 1, 3-(1'-m-iodobenzyloxyethyl)-17(2)-{(2-deoxy)glucose}pyropheophorbide-a 2, and 3-(1'-m-iodobenzyloxyethyl)-17(2)-{(1-deoxy)galactose}pyropheophorbide-a 3 were synthesized and converted into the corresponding (124)I-labeled analogues by reacting the intermediate trimethyltin analogues with Na(124)I. Photosensitizers 1-3 were evaluated for the PDT efficacy in C3H mice bearing RIF tumors at variable doses and showed a significant long-term tumor cure. Among the compounds investigated, the non-carbohydrate analogue 1 was most effective. These results were in contrast to the in vitro data, where compared to the parent analogue the corresponding galactose and glucose derivatives showed enhanced cell kill. Among the corresponding (124)I-labeled analogues, excellent tumor images were obtained from compound 1 in both tumor models (RIF and Colon-26) and the best tumor contrast was observed at 72 h after injection. Conjugating a glucose moiety to photosensitizer 1 initially diminished its tumor uptake, whereas with time the corresponding galactose analogue showed improved tumor contrast.
Pandey
Suresh K
SK
PDT Center, Roswell Park Cancer Institute, Buffalo, New York 14263, USA.
Sajjad
Munawwar
M
Chen
Yihui
Y
Zheng
Xiang
X
Yao
Rutao
R
Missert
Joseph R
JR
Batt
Carrie
C
Nabi
Hani A
HA
Oseroff
Allan R
AR
Pandey
Ravindra K
RK
D000818:Animals; D002734:Chlorophyll / Q000031:analogs & derivatives* / Q000737:chemistry / Q000493:pharmacokinetics / Q000627:therapeutic use; D002851:Chromatography, High Pressure Liquid; D005690:Galactose / Q000737:chemistry*; D005947:Glucose / Q000737:chemistry*; D007457:Iodine Radioisotopes / Q000627:therapeutic use*; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D051379:Mice; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D010778:Photochemotherapy; D049268:Positron-Emission Tomography / Q000379:methods*; D013056:Spectrophotometry, Ultraviolet; D014018:Tissue Distribution
D007457:Iodine Radioisotopes; C535239:methyl-3-(1'-iodobenzyloxyethyl)pyropheophorbide-a; D002734:Chlorophyll; D005947:Glucose; D005690:Galactose