15-Lipoxygenase-1 re-expression in colorectal cancer alters endothelial cell features through enhanced expression of TSP-1 and ICAM-1

Abstract

15-lipoxygenase-1 (15-LOX-1) oxygenates linoleic acid to 13(S)-hydroxyoctadecadienoic acid (HODE). The enzyme is widely suppressed in different cancers and its re-expression has tumor suppressive effects. 15-LOX-1 has been shown to inhibit neoangiogenesis in colorectal cancer (CRC); in the present study we confirm this phenomenon and describe the mechanistic basis. We show that re-expression of 15-LOX-1 in CRC cell lines resulted in decreased transcriptional activity of HIF1α and reduced the expression and secretion of VEGF in both normoxic and hypoxic conditions. Conditioned medium (CM) was obtained from CRC or prostate cancer cell lines re-expressing 15-LOX-1 (15-LOX-1CM). 15-LOX-1CM treated aortic rings from 6-week old C57BL/6 mice showed significantly less vessel sprouting and more organized structure of vascular network. Human umbilical vein endothelial cells (HUVECs) incubated with 15-LOX-1CM showed reduced motility, enhanced expression of intercellular cell adhesion molecule (ICAM-1) and reduced tube formation but no change in proliferation or cell-cycle distribution. HUVECs incubated with 13(S)-HODE partially phenocopied the effects of 15-LOX-1CM, i.e., showed reduced motility and enhanced expression of ICAM-1, but did not reduce tube formation, implying the importance of additional factors. Therefore, a Proteome Profiler Angiogenesis Array was carried out, which showed that Thrombospondin-1 (TSP-1), a matrix glycoprotein known to strongly inhibit neovascularization, was expressed significantly more in HUVECs incubated with 15-LOX-1CM. TSP-1 blockage in HUVECs reduced the expression of ICAM-1 and enhanced cell motility, thereby providing a mechanism for reduced angiogenesis. The anti-angiogenic effects of 15-LOX-1 through enhanced expressions of ICAM-1 and TSP-1 are novel findings and should be explored further to develop therapeutic options.

15‐LOX‐1 has diverse roles in the resensitization of resistant cancer cell lines to doxorubicin

“…Since 15-LOX-1 was downregulated in doxorubicin-resistant cells compared with their drug-sensitive parental cells, we next examined whether ectopic overexpression of 15-LOX-1 affected drug resistance. We used a mammalian overexpression vector (pcDNA3.1[−]-ALOX15) that was previously designed and confirmed to produce a functional 15-LOX-1 protein (Cimen et al, 2009;Tuncer et al, 2017).…”

“…Moreover, 15-LOX-1 has also been linked to the regulation of necrosis via regulating intracellular redox state by cooperating with 12-lipoxygenase (Berghe, Linkermann, Jouan-Lanhouet, Walczak, & Vandenabeele, 2014). 15-LOX-1 has been demonstrated to be associated with tumorigenesis in different tissue types, and was reported to be mostly downregulated in cancer cells (Moussalli et al, 2011;Tian et al, 2017;Tuncer et al, 2017). In breast cancer, immunohistochemistry as well as gene expression studies have indicated a downregulation of ALOX15 expression in the tumor tissues compared to normal cells (Jiang, Watkins, Douglas-Jones, & Mansel, 2006).…”

Emerging cellular functions of the lipid metabolizing enzyme 15‐Lipoxygenase‐1

“…Complicating the story even further, recently, 15‐LOX‐1 over‐expression in PC‐3 cells was shown to reduce angiogenesis through a ubiquitin‐mediated enhanced degradation of HIF‐1α and a consequent lower expression of VEGF‐A mRNA . Supporting the anti‐angiogenic role of 15‐LOX‐1, we have recently shown that re‐expression of 15‐LOX‐1 in HCT‐116 and SW‐480 CRC cell lines and LNCaP prostate cancer cells reduced the expression and secretion of VEGF‐A in both normoxic and hypoxic conditions and CM from these cells decreased endothelial cell motility and tube formation . Moreover, 15‐LOX‐1 CM treated mouse aortic rings showed significantly less sprouting with a more organized (less chaotic) structure of vascular network .…”

“…Moreover, 15‐LOX‐1 CM treated mouse aortic rings showed significantly less sprouting with a more organized (less chaotic) structure of vascular network . Mechanistically, endothelial cells treated with CM from 15‐LOX‐1 overexpressing CRC cell lines showed enhanced expression of Thrombospondin‐1 (TSP‐1), a matrix glycoprotein known to strongly inhibit neovascularization . TSP‐1 interacts with a vast number of different proteins, many of which play important roles in extracellular matrix remodelling, interactions between cells and the cell and extracellular matrix, motility and vascular normalization .…”

Sciadonic acid derived from pine nuts as a food component to reduce plasma triglycerides by inhibiting the rat hepatic Δ9-desaturase

“…Produced by endothelial cells, it would behave like an anti-inflammatory metabolite as a ligand for PPAR α and γ. Its synthesis led to reduce angiogenesis in colon and prostate cancer 44 or enhanced the axonal outgrowth in primary cortical neurons during development of rats in a gender-dependent manner 45 . Altogether, these works underline the pleiotropic dimension of action of HODEs.…”