Interplay between 15-lipoxygenase-1 and metastasis-associated antigen 1 in the metastatic potential of colorectal cancer.
OBJECTIVE
Metastasis-associated antigen 1 (MTA1) is implicated in metastasis while 15-lipoxygenase-1 (15-LOX-1) reduces cell motility, when re-expressed in colorectal cancer (CRC). We aimed to understand any potential interplay between MTA1 and 15-LOX-1 in CRC metastasis.


METHODS
ALOX15 and MTA1 expression in tumour and normal samples were analysed from TCGA RNA-seq data, microarray data sets and a human CRC cDNA array. Western blots, chromatin immunoprecipitation (ChIP), luciferase assays and electrophoretic mobility shift assays (EMSA) were carried out in HT-29 and LoVo cells re-expressing 15-LOX-1 to determine NF- κB activity at the MTA1 promoter. Functional assays in cells ectopically expressing either 15-LOX-1, MTA-1 or both, were carried out to determine adhesion and cell motility.


RESULTS
Significantly higher expression of MTA1 was observed in tumours compared to normal tissues; MTA1 overexpression resulted in reduced adhesion in CRC cell lines. Re-expression of 15-LOX-1 in the CRC cell lines reduced expression of endogenous MTA1, corroborated by negative correlation between the two genes in two independent human CRC microarray data sets, with greater significance in specific subsets of patients. DNA binding and transcriptional activity of NF-κB at the MTA1 promoter was significantly lower in cells re-expressing 15-LOX-1. Functionally, the same cells had reduced motility, which was rescued when they overexpressed MTA1, and further corroborated by expressions of E-cadherin and vimentin.


CONCLUSIONS
Expression of MTA1 and 15-LOX-1 negatively correlated in specific subsets of CRC. Mechanistically, this is at least in part through reduced recruitment of NF-κB to the MTA1 promoter.
Department of Biological Sciences, Middle East Technical University, Ankara, Turkey.
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Tunçer
Department of Biological Sciences, Middle East Technical University, Ankara, Turkey.
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Tunçay Çağatay
Department of Molecular Biology and Genetics, Bilkent University, Ankara, Turkey.
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Keşküş
Department of Biological Sciences, Middle East Technical University, Ankara, Turkey.
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Çolakoğlu
Department of Molecular Biology and Genetics, Bilkent University, Ankara, Turkey.
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Ö
Konu
Department of Biological Sciences, Middle East Technical University, Ankara, Turkey.
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Banerjee
D001093:Arachidonate 15-Lipoxygenase / Q000235:genetics*; D045744:Cell Line, Tumor; D002465:Cell Movement; D003106:Colon / Q000378:metabolism / Q000473:pathology; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000473:pathology; D015972:Gene Expression Regulation, Neoplastic; D006655:Histone Deacetylases / Q000235:genetics*; D006801:Humans; D011401:Promoter Regions, Genetic; D012007:Rectum / Q000378:metabolism / Q000473:pathology; D012097:Repressor Proteins / Q000235:genetics*; D015534:Trans-Activators
C089320:MTA1 protein, human; D012097:Repressor Proteins; D015534:Trans-Activators; C515716:ALOX15 protein, human; D001093:Arachidonate 15-Lipoxygenase; D006655:Histone Deacetylases