Over the course of the last several years, we have found that vairous redox related species such as nitric oxide play a major role in the promotion of angiogenesis as well as part of the inflammatory response. A recent study has shown that NO regulates a number of proteins such as TSP-1, TGF beta, metallo matrix proteases (MMP), TIMP, HIF-1alpha, Akt, ERK and p53. We have found a correlation been Akt and Nitric oxide synthase in breast cancer patients. We have begun to correlate our molecular studies in vitro with patient slides. These ahve begun to provide us insight into the role this small diatomic radical associated with oxidative stress plays in cancer. Another important aspect to this project is to see if we can develop compounds that can reverse the interactions of NO and the stimulation of these pro-growth effects. In animal models, we have found NOS inhibitors can induce a tumor re-growth delay after radiation thus improving the efficacy of these treatments. It was further found that it was the inflammatory response after treatment rather than simple its anti-angiogenic effect. We have been investigating the role of NO in the regulation of interferon gamma and IL-10. The final aspect of this project was the discovery with collaboration in the CCR, that the protein thrombospondin-1 (TSP-1, a antiangiogenic molecule) was the antagonist to NO/cGMP. Furthermore, we found nitric oxide antagonizes TSP-1. Removal of TSP-1 and its receptor CD47 improve normal tissue radiation induced damage and ischemia reperfusion injury. We are currently working on small molecules that can down regulate TSP-1 in vivo that improves blood flow. In collaboration with Dr. Wiltrout's we have found that IL-2/antiCD40 therapy involved with nitric oxide and specifically NOS2. We found that high NO propduced in the tumor reduced metastatic. The clinical used ratio of MMP9 and E-cadherin was increased with NOS inhibitors. It is become clear that different levels of NO produced in the tumor region can have beneficial effects for some cancer yet make them radioresistance through the control of the immune system.
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