Sivelestat, a specific neutrophil elastase inhibitor, suppresses the growth of gastric carcinoma cells by preventing the release of transforming growth factor‐α

Abstract

Neutrophil elastase is a neutral serine proteinase produced by polymorphonuclear leukocytes and monocytes/macrophages, especially under surgical stress. In the present study, we investigated whether NE promotes cell growth by activation of EGFR to elucidate whether surgical stress induces tumor proliferation and progression. Furthermore, we examined the antitumor effect of a specific NE inhibitor, sivelestat. Cell growth assays were carried out in vitro and in vivo using TMK-1 gastric cancer cells. TMK-1 cell growth was stimulated to 118% of that of the control cells after 48 h stimulation with 1 µ µ µ µg/mL NE according to an MTT assay. Sivelestat inhibited cell growth to 23.4 and 58.0% of control values at concentrations of 100 and 1000 µ µ µ µg/mL, respectively. NE rapidly phosphorylated EGFR in only 5 min and triggered the ERK1/2-mitogenic signaling pathway in TMK-1. It was further demonstrated that NE-induced EGFR phosphorylation was transactivated through TGF-α α α α, using ELISA. (1) NE degrades a broad spectrum of extracellular matrix and cell surface proteins, such as elastin, interstitial collagens, proteoglycans, fibronectin, laminin, and type IV collagens.(2-5) Under normal physiological conditions, the proteolytic activity of elastase released by recruited neutrophils is strictly regulated by antiproteases, such as alpha-1-protease inhibitor and secretary leukoprotease inhibitor. However, under conditions of physiological disturbance, such as the presence of neoplasms, surgical stress, or inflammation, the balance between elastase and antiprotease is disrupted, and the predominant elastolytic activity causes the destruction of THE extracellular matrix. NE also cleaves pro-TGF-α on the surface of human airway epithelial cells through its proteolytic activity and releases mature, soluble TGF-α on human airway epithelial cells.(6) Release of TGF-α activates the EGFR signaling cascade, (6) resulting in mucinous secretion in the peripheral airways that might cause severe respiratory complications after major surgical stress or severe inflammatory response.Recently, a specific synthetic NE inhibitor, sivelestat, has been developed and used clinically in Japan for the treatment of various inflammatory diseases. The anti-inflammatory effects of sivelestat are effective for the alleviation of surgical stress, and can reduce morbidity and organ dysfunction, including acute respiratory distress syndrome. As mentioned above, sivelestat inhibits the NE-induced release of TGF-α from the cell membrane.As we have previously demonstrated, gastric and esophageal carcinoma cells have been found to have multi-autocrine loops for the development of growth and metastatic potential (7)(8)(9)(10)(11) in laboratory studies. In the clinical setting, relapses or rapid recurrences are often observed after extensive resection of gastric and esophageal tumors, suggesting that strong inflammatory responses are present, including the release of NE, which might cause the rapid spread of cancer cells. These facts prompted us to exam...

Neutrophils in cancer

“…With IRS‐1 degraded, more PI‐3K is available for driving the proliferation of cancer cells. Besides in lung carcinoma cells , such a protumorigenic role of NE was also observed in breast cancer , gastric cancer , and esophageal cancer . In esophageal cancer, NE seemed to be able to promote tumor cell migration .…”

Cxcr1 mediates recruitment of neutrophils and supports proliferation of tumor-initiating astrocytes in vivo

“…One of the potential mechanisms for this interaction is through the production of neutrophil elastase (NE), which has been shown to enhance proliferation of cancer and other cell types in culture 49–53 . Indeed, inhibitors of NE have previously been suggested as potential anti-cancer therapeutic targets by several groups 54–57 . In addition to their demonstrated role in the primary TME, neutrophils have also been implicated in priming the metastatic niche for secondary tumor growth 58 .…”

Neutrophil elastase as a diagnostic marker and therapeutic target in colorectal cancers

“…The imbalance between NE and anti-protease also enhances the NE-induced tumor development. Except degradation of IRS-1, NE also cleaves pro-TGF-α to release mature TGF-α in gastric TMK-1 cells, which activates EGFR-induced tumor proliferation [31, 32]. Based on these evidences, blockage of NE activity is a good rational therapeutic target.…”