title: Tumor necrosis factor-alpha-induced accentuation in cryoinjury: mechanisms in vitro and in vivo.
abstract: Cryosurgical treatment of solid cancer can be greatly assisted by further translation of our finding that a cytokine adjuvant tumor necrosis factor-alpha (TNF-alpha) can achieve complete cancer destruction out to the intraoperatively imaged iceball edge (-0.5 degrees C) over the current clinical recommendation of reaching temperatures lower than -40 degrees C. The present study investigates the cellular and tissue level dose dependency and molecular mechanisms of TNF-alpha-induced enhancement in cryosurgical cancer destruction. Microvascular endothelial MVEC and human prostate cancer LNCaP Pro 5 (LNCaP) cells were frozen as monolayers in the presence of TNF-alpha. Normal skin and LNCaP tumor grown in a nude mouse model were also frozen at different TNF-alpha doses. Molecular mechanisms were investigated by using specific inhibitors to block nuclear factor-kappaB-mediated inflammatory or caspase-mediated apoptosis pathways. The amount of cryoinjury increased in a dose-dependent manner with TNF-alpha both in vitro and in vivo. MVEC were found to be more cryosensitive than LNCaP cells in both the presence and the absence of TNF-alpha. The augmentation in vivo was significantly greater than that in vitro, with complete cell death up to the iceball edge in tumor tissue at local TNF-alpha doses greater than 200 ng. The inhibition assays showed contrasting results with caspase-mediated apoptosis as the dominant mechanism in MVEC in vitro and nuclear factor-kappaB-mediated inflammatory mechanisms within the microvasculatures the dominant mechanism in vivo. These results suggest the involvement of endothelial-mediated injury and inflammation as the critical mechanisms in cryoinjury and the use of vascular-targeting molecules such as TNF-alpha to enhance tumor killing and achieve the clinical goal of complete cell death within an iceball.
authors: Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN 55455, USA.
authors: Jing
authors: J
authors: Jiang
authors: Raghav
authors: R
authors: Goel
authors: M Arif
authors: MA
authors: Iftekhar
authors: Rachana
authors: R
authors: Visaria
authors: John D
authors: JD
authors: Belcher
authors: Gregory M
authors: GM
authors: Vercellotti
authors: John C
authors: JC
authors: Bischof
mesh_terms: D000818:Animals; D017209:Apoptosis; D045744:Cell Line, Tumor; D003452:Cryosurgery; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D016328:NF-kappa B / Q000037:antagonists & inhibitors; D011994:Recombinant Proteins / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
chemical_list: D016328:NF-kappa B; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha