title: Imaging of therapy-induced apoptosis using (99m)Tc-HYNIC-annexin V in thymoma tumor-bearing mice.
abstract: The primary focus of this study was to assess the potential of (99m)Tc-HYNIC-Annexin V for in vivo imaging of apoptosis after systemic chemotherapy and "more localized" radiotherapy in nude mice bearing thymoma tumors and correlating it with TUNEL staining. (99m)Tc-HYNIC-Annexin V was administered intravenously to tumor-bearing mice (n = 25) before and after therapy. Mice were then imaged at 4 hours postinjection, and the animals were subsequently sacrificed. Tumor uptake increased significantly in response to treatment [chemotherapy (n = 8): 1.80 +/- 0.52 %ID/g, p < 0.009; radiotherapy (n = 7): 0.81 +/- 0.07 %ID/g, p < 0.02], compared to the control group (n = 10) (0.57 +/- 0.05 %ID/g). Tumor-to-muscle (T:M) and tumor-to-blood (T:B) ratios were significantly higher in both chemotherapy-treated (p < 0.02 and p < 0.01) and radiotherapy-treated cohorts (p < 0.05 and p < 0.03), compared to the control cohorts at 4 hours postinjection of (99m)Tc-Annxin V. In the post-therapy cohorts, the immunohistochemistry studies indicated a statistically significant correlation between tumor uptake of (99m)Tc-HYNIC-Annexin V and the extent of apoptosis detected by TUNEL-positive staining (r(2) = 0.41). The physiologic localization of the agent was found mainly in the kidneys (34%), liver (11%), and urine (22%). The results suggest that (99m)Tc-HYNIC-Annexin V may be an ideal agent for imaging apoptosis in response to treatment in a thymoma tumor bearing mouse model.
authors.affiliation: Department of Nuclear Medicine, The St. George Hospital, Kogarah, New South Wales, Australia.
authors.forename: Effie
authors.initials: E
authors.lastname: Wong
authors.forename: Vijay
authors.initials: V
authors.lastname: Kumar
authors.forename: Robert B
authors.initials: RB
authors.lastname: Howman-Giles
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Vanderheyden
mesh_terms: D000818:Animals; D017304:Annexin A5; D018906:Antineoplastic Agents, Alkylating / Q000627:therapeutic use; D017209:Apoptosis / Q000187:drug effects* / Q000528:radiation effects*; D003131:Combined Modality Therapy; D003520:Cyclophosphamide / Q000627:therapeutic use; D004195:Disease Models, Animal; D020287:In Situ Nick-End Labeling; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D015609:Organotechnetium Compounds; D011839:Radiation, Ionizing; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D011879:Radiotherapy Dosage; D013945:Thymoma / Q000000981:diagnostic imaging* / Q000473:pathology / Q000628:therapy; D013953:Thymus Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000628:therapy; D014018:Tissue Distribution
chemical_list: D017304:Annexin A5; D018906:Antineoplastic Agents, Alkylating; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; C117287:technetium Tc 99m HYNIC annexin V; D003520:Cyclophosphamide