rIFN-γ-activated rat neutrophils induce tumor cell apoptosis by nitric oxide

Abstract

We have previously shown that 1) neutrophils activated with various cytokines, including rat recombinant interferon g (rIFN-g), inhibit tumor cell growth and that 2) nitric oxide (NO) is the effector molecule in tumor inhibition by rIFN-gstimulated rat peritoneal exudate neutrophils. In this study, we examined the nature of tumor cell death induced by rat peritoneal neutrophils activated by rIFN-g in order to clarify the mechanism of apoptosis in neoplastic tumor cell death. DNA of 3 syngeneic rat tumor cell lines was significantly fragmented within 3 hr of incubation in the presence of rIFNg-activated neutrophils, and this effect was dependent on both the concentration of rIFN-g and the number of neutrophils. This DNA fragmentation was inhibited by L-N-(1-iminoethyl)-ornithine (L-NIO), a NO synthase inhibitor, but not by superoxide dismutase (SOD). Tumor cells treated with the activated neutrophils were shown by electron microscopy to be apoptotic, exhibiting necrotic features with a longer incubation. On the other hand, cytolysis of tumor cells, as determined by a [ 3 H]-uridine release assay, was first observed only at 24 hr of incubation with the rIFN-g-activated neutrophils. Taken together, our results suggest that tumor cell apoptosis by activated neutrophils is NO-dependent and that apoptotic tumor cells undergo necrosis as a secondary process. We suggest that tumor cell apoptosis induced by activated neutrophils plays an important role in regulation of neoplastic tumor cell growth and death in vivo.

The Multifaceted Roles Neutrophils Play in the Tumor Microenvironment

“…[312,313] • The growth of disialoganglioside (GD2) positive neuroblastoma cells was inhibited by neutrophils in the presence of antibodies towards GD2, an effect that was enhanced by GM-CSF.…”

“…• The presence of MPO in the tumor microenvironment was accompanied by the formation of lipid peroxidase [416] CXCL5 and IL-8) may promote the generation of antitumorigenic neutrophils [32,66,[309][310][311][312][313]. Anti-tumorigenic neutrophils can also be generated artificially by exposing them to the phorbol ester PMA, or to the lectins Concanavalin A or wheat germ agglutinin (WGA) [314][315][316][317][318].…”

“…Dissemond and colleagues showed that SOD in combination with catalase could partly prevent tumor cell killing with an involvement of nitric oxide in the killing process [325]. Rat neutrophils stimulated with IFNγ produced nitric oxide that prevented tumor cell growth [312] and induced apoptosis of the tumor cells [313]. However, another study [13] could not relieve the cytotoxic effect with a nitric oxide scavenger.…”

Phagocytic Activity and Nitric Oxide Production of Circulating Polymorphonuclear Leukocytes from Patients with Peritoneal Carcinomatosis

“…First, PMNC possess a range of potent proteinases and hydrolases, as well as the ability to generate a series of reactive oxygen and nitrogen intermediates, all of them having the potential for inhibiting tumor growth. For example, Uchida et al have shown that tumor cell apoptosis by rIFN-gama activated neutrophils is mediated by Larginine-deriveded nitrogen oxidation products (31). In addition, recombinant, fully human IgA1, Fc alpha RI or Fc gamma RI-directed antitumor bispecific antibody mediated specific lysis of appropriate tumor antigenexpressing target cells with purified PMNCs (32).…”

Neutralization by "antineoplastin" of insulin-activated nitric oxide synthase antibody and its effects in cancers

“…It has also been reported that the tumoricidal effects of lipopolysaccharides and c-interferon are mediated through the production of NO by the macrophages (Dong et al 1993;Uchida et al 1997). Although these studies on the antineoplastic properties of NO suggest that the messenger molecule could have an important role in the prevention/control of cancer, the identity of the physiologic stimulator for the synthesis of NO that would result in the inhibition of the neoplastic development remains obscure.…”