15‐Lipoxygenase‐1 expression suppresses the invasive properties of colorectal carcinoma cell lines HCT‐116 and HT‐29

Abstract

Colorectal carcinoma (CRC) is often lethal when invasion and ⁄ or metastasis occur. 15-Lipoxygenase-1 (15-LO-1), a member of the inflammatory eicosanoid pathway, oxidatively metabolizes linoleic acid and its expression is repressed in CRC. In this study, we investigated the hypothesis that the lack of 15-LO-1 expression in CRC cells might contribute to tumorigenesis. Therefore we introduced 15-LO-1 into HCT-116 and HT-29 cells that do not have detectable levels of 15-LO-1. Our data indicate that expression of 15-LO-1 significantly decreased cell proliferation and increased apoptosis. In addition, we observed a reduction in adhesion to fibronectin, anchorage-independent growth on soft agar, cellular motility and ability to heal a scratch wound, and migratory and invasive capacity across Matrigel. 15-LO-1 expression also reduced the expression of metastasis associated protein-1, a part of the nucleosome remodeling and histone deacetylase silencing complex. We propose that 15-LO-1 expression in CRC might contribute to the inhibition of metastatic capacity in vitro and can be exploited for therapeutic purposes. (Cancer Sci 2009; 100: 2283-2291 C olorectal cancer is one of the leading causes of cancerrelated deaths throughout the world.(1) There is growing evidence that supports a functional role for the inflammatory COX and LO enzymes in cancer development.(2-4) LOs, which can oxygenate arachidonic acid and linoleic acid, can be classified as procarcinogenic or anticarcinogenic; thus, 5-, 8-, and 12-LO are classified as procarcinogenic, whereas 15-LO-2 is anticarcinogenic.(5,6) 15-LO-1, however, has a controversial role in cancer. This enzyme preferentially catalyzes the conversion of linoleic acid to 13(S)-HODE. (7,8) 15-LO-1 has been unambiguously shown to have a protumorigenic role in prostate cancer and preliminary reports in CRC also assigned a procarcinogenic role to 15-LO-1 through activation of the MAPK pathway. (9)(10)(11)(12)(13)(14)(15) However, surprisingly, subsequent studies have indicated a tumor suppressive nature of the enzyme as its expression was shown to be lost in CRC by immunohistochemistry. (16,17) Promoter analysis of ALOX15 indicated that expression of the gene is suppressed in tumors by several mechanisms acting in concert, such as promoter methylation, (18) binding of the nucleosome remodeling and histone deacetylase repression complex, (19) and through the overexpression of the transcription factor GATA-6. (20) Forced expression of the enzyme in various colon cancer cell lines has shown a downregulation of anti-apoptotic proteins and activation of apoptotic pathways. (21)(22)(23)(24)(25) The gene can also be transcriptionally reactivated by histone deacetylase inhibitors and non-steroidal anti-inflammatory drugs to induce apoptosis. (26,27) Additionally, selective molecular targeting of 15-LO-1 expression was shown to be sufficient to inhibit tumorigenesis in mice.(24) A similar tumor suppressive role of 15-LO-1 has also been observed in bladder and pancreatic cancers. (11,28) Although mu...

Mammalian lipoxygenases and their biological relevance

“…Since cell cycle regulation is impacted by the redox equilibrium [126] the observed anti-proliferative effect might not directly be related to ALOX15 inhibition. In similar cellular models of colorectal carcinoma (HCT116, HT29) ALOX15 exhibited anti-carcinogenic properties, which was related to inhibition of the anti-apoptotic effect of the inflammatory transcription factor nuclear factor kappa B [127]. Here again, the molecular basis for the observed anti-carcinogenic affect is not completely understood but overexpression of ALOX15 inhibited the degradation of the inhibitor of kappa B, impaired nuclear translocation of p65 and p50, decreased DNA binding in the nucleus and reduced the transcriptional activity of NF-κB [128].…”

Differential cell growth/apoptosis behavior of 13-hydroxyoctadecadienoic acid enantiomers in a colorectal cancer cell line

“…In this sense, 15-LOX metabolites have been shown to play both pro-and antitumorigenic actions, whereas COX metabolites are described to be tumorigenic (42). Thus, while the expression of 15-LOX-1 inhibited intestinal epithelial cell proliferation (12,13), the expression of COXs is mitogenic (15).…”

“…COX has two isoforms (COX-1 and COX-2) and produces prostaglandins (PGs) and thromboxanes. LOXs constitute a family of dioxygenases that insert molecular oxygen into free and/or esterified polyunsaturated fatty acids with regional specificity and are designated 5-, 8-, 12-and 15-LOX, accordingly (12,13). Thus these enzymes metabolize AA to the biologically active metabolites hydroperoxyeicosatetraenoic acids, which on reduction form corresponding hydroeicosatetranoic acids (HETEs), while the metabolism of linoleic acid preferentially results in the formation of hydroxyoctadecadienoic acids (HODEs).…”

miR-125b Targets ARID3B in Breast Cancer Cells

“…The monolayer of cells was scratched with a sterile pipette tip (Cimen et al, 2009). Cell debris was removed by washing twice with Hank's Salt solution.…”

“…Transwell migration assay was performed as previously described (Cimen et al, 2009). MCF7-125 and MCF7-EV cells were cultured in MEM-Earle's medium with 1% FBS.…”