title: Antiangiogenic action of redox-modulating Mn(III) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin, MnTE-2-PyP(5+), via suppression of oxidative stress in a mouse model of breast tumor.
abstract: MnTE-2-PyP(5+) is a potent catalytic scavenger of reactive oxygen and nitrogen species, primarily superoxide and peroxynitrite. It therefore not only attenuates primary oxidative damage, but was found to modulate redox-based signaling pathways (HIF-1alpha, NF-kappaB, SP-1, and AP-1) and thus, in turn, secondary oxidative injury also. Cancer has been widely considered an oxidative stress condition. The goal of this study was to prove if and why a catalytic SOD mimic/peroxynitrite scavenger would exert anti-cancer effects, i.e., to evaluate whether the attenuation of the oxidative stress by MnTE-2-PyP(5+) could suppress tumor growth in a 4T1 mouse breast tumor model. Tumor cells were implanted into Balb/C mouse flanks. Three groups of mice (n=25) were studied: control (PBS) and 2 and 15 mg/kg/day of MnTE-2-PyP(5+) given subcutaneously twice daily starting when the tumors averaged 200 mm(3) (until they reached approximately 5-fold the initial volume). Intratumoral hypoxia (pimonidazole, carbonic anhydrase), HIF-1alpha, VEGF, proliferating capillary index (CD105), microvessel density (CD31), protein nitration, DNA oxidation (8-OHdG), NADPH oxidase (Nox-4), apoptosis (CD31), macrophage infiltration (CD68), and tumor drug levels were assessed. With 2 mg/kg/day a trend toward tumor growth delay was observed, and a significant trend was observed with 15 mg/kg/day. The 7.5-fold increase in drug dose was accompanied by a similar (6-fold) increase in tumor drug levels. Oxidative stress was largely attenuated as observed through the decreased levels of DNA damage, protein 3-nitrotyrosine, macrophage infiltration, and NADPH oxidase. Further, hypoxia was significantly decreased as were the levels of HIF-1alpha and VEGF. Consequently, suppression of angiogenesis was observed; both the microvessel density and the endothelial cell proliferation were markedly decreased. Our study indicates for the first time that MnTE-2-PyP(5+) has anti-cancer activity in its own right. The anti-cancer activity via HIF/VEGF pathways probably arises from the impact of the drug on the oxidative stress. Therefore, the catalytic scavenging of ROS/RNS by antioxidants, which in turn suppresses cellular transcriptional activity, could be an appropriate strategy for anti-cancer therapy. Enhancement of the anti-cancer effects may be achieved by optimizing the dosing regime, utilizing more bioavailable Mn porphyrins (MnP), and combining MnP treatment with irradiation, hyperthermia, and chemotherapy. Mn porphyrins may be advantageous compared to other anti-cancer drugs, owing to their radioprotection of normal tissue and the ability to afford pain management in cancer patients via prevention of chronic morphine tolerance.
authors: Department of Radiation Oncology, Duke University School of Medicine, Durham, NC 27710, USA.
authors: Zahid N
authors: ZN
authors: Rabbani
authors: Ivan
authors: I
authors: Spasojevic
authors: Xiuwu
authors: X
authors: Zhang
authors: Benjamin J
authors: BJ
authors: Moeller
authors: Sinisa
authors: S
authors: Haberle
authors: Jeannette
authors: J
authors: Vasquez-Vivar
authors: Mark W
authors: MW
authors: Dewhirst
authors: Zeljko
authors: Z
authors: Vujaskovic
authors: Ines
authors: I
authors: Batinic-Haberle
mesh_terms: D020533:Angiogenesis Inhibitors / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D000818:Animals; D000970:Antineoplastic Agents / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D017209:Apoptosis / Q000187:drug effects; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D049109:Cell Proliferation / Q000187:drug effects; D007150:Immunohistochemistry; D007249:Inflammation / Q000188:drug therapy; D008325:Mammary Neoplasms, Experimental / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D008665:Metalloporphyrins / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D051379:Mice; D008807:Mice, Inbred BALB C; D009389:Neovascularization, Pathologic / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000187:drug effects*
chemical_list: D020533:Angiogenesis Inhibitors; D000970:Antineoplastic Agents; D008665:Metalloporphyrins; C431023:manganese (III) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin