Tumor necrosis factor-α–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-A (TNF-A) can achieve complete cancer destruction out to the intraoperatively imaged iceball edge (-0.5°C) over the current clinical recommendation of reaching temperatures lower than -40°C. The present study investigates the cellular and tissue level dose dependency and molecular mechanisms of TNF-A-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-A. Normal skin and LNCaP tumor grown in a nude mouse model were also frozen at different TNF-A doses. Molecular mechanisms were investigated by using specific inhibitors to block nuclear factor-KB -mediated inflammatory or caspasemediated apoptosis pathways. The amount of cryoinjury increased in a dose-dependent manner with TNF-A 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-A. 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-A 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-KB -mediated inflammatory mechanisms within the microvasculatures the dominant mechanism in vivo. These results suggest the involvement of endothelialmediated injury and inflammation as the critical mechanisms in cryoinjury and the use of vascular-targeting molecules such as TNF-A to enhance tumor killing and achieve the clinical goal of complete cell death within an iceball.

Nanoparticle Delivered Vascular Disrupting Agents (VDAs): Use of TNF-Alpha Conjugated Gold Nanoparticles for Multimodal Cancer Therapy

“…Based on our previously published results, we hypothesized that increased recruitment of neutrophils is essential for the enhanced cryosurgical lesion due to nanoparticle preconditioning 15, 23 . To elucidate the role of the inflammatory cell response, we first investigated the recruitment of neutrophils to DSFC LNCaP tumor tissue during the 4 hour period after NP-TNF administration by myeloperoxidase staining.…”

“…In addition, we have shown an increase in the deposition of fibrinogen 4 hours after the injection of NP-TNF suggesting optimal conditions have been created to augment or sustain vascular stasis through thrombosis. Furthermore, NP-TNF alone has been shown previously to increase endothelial cell death alone (another hallmark of a VDA response) 16, 23 . Finally, all of these VDA related mechanisms, which are enhanced by nanoparticle delivery, are occurring within the context of reduced systemic toxicity as indicated by a greater than three-fold increase in maximum tolerated dose in a recent clinical trial 13 .…”

Adjuvant Approaches to Enhance Cryosurgery

“…TNF-α is closely associated with multiple vascular events such as endothelial cell apoptosis, increase in procoagulant activity, decrease in anticoagulant activity, recruitment and adherence of inflammatory cells such as neutrophils, and production of other cytokines [95-97]. In a mouse model of human prostate cancer, it was shown that TNF-α increases the thermal threshold of tissue damage in a dose-dependent manner [37, 97-99]. This augmentation was observed when TNF-α was delivered both locally or systemically, about 3-4 hours before cryosurgery.…”

“…This augmentation was observed when TNF-α was delivered both locally or systemically, about 3-4 hours before cryosurgery. Later, it was also shown that the this enhancement was a result of direct TNF-α action on the endothelium and more importantly on the induction of inflammatory pathways leading to an improved vascular response [99]. But like many other stand–alone cytotoxic drugs used in cancer treatment, the systemic delivery of required amounts of TNF-α is a major obstacle to achieve rapid clinical translation of this finding.…”

Wide-field functional imaging of blood flow and hemoglobin oxygen saturation in the rodent dorsal window chamber

“…The dorsal window chamber has found utility in many biomedical research applications, notably in studies of angiogenesis (Dellian et al, 1996; Laschke and Menger, 2007) and tumor progression, evaluation of microvascular-targeted biomolecular therapies (Yuan et al, 1996), evaluation of cryosurgical destruction on human prostate cancer (Chao et al, 2004; Jiang et al, 2008), evaluation of light-based therapies targeting the microvasculature (Choi et al, 2008), and evaluation of topically applied chemical enhancement of light-based therapy (Vargas et al, 2008). Tumor studies have been performed via implantation of tumor cell lines or primary tumor cells into the dorsal window chamber, allowing for direct visualization of the entire tumor and the surrounding vasculature (Dewhirst et al, 2000; Jain et al, 2002).…”