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Oxidized LDL receptor 1 (OLR1) as a possible link between obesity, dyslipidemia and cancer.

Khaidakov M, Mitra S, Kang BY, Wang X, Kadlubar S, Novelli G, Raj V, Winters M, Carter WC, Mehta JL - PLoS ONE (2011)

Bottom Line: Further studies revealed broad inhibition of NF-kB target genes outside of the transformation-associated gene pool, with enrichment themes of defense response, immune response, apoptosis, proliferation, and wound healing.Forced over-expression of OLR1 resulted in upregulation of NF-κB (p65) and its target pro-oncogenes involved in inhibition of apoptosis (BCL2, BCL2A1, TNFAIP3) and regulation of cell cycle (CCND2) in both cell lines.We conclude that OLR1 may act as an oncogene by activation of NF-kB target genes responsible for proliferation, migration and inhibition of apoptosis and de novo lipogenesis genes.

View Article: PubMed Central - PubMed

Affiliation: Department of Internal Medicine, College of Medicine, and the Central Arkansas Veterans Healthcare System, Little Rock, Arkansas, United States of America. mkhaidakov@uams.edu

ABSTRACT
Recent studies have linked expression of lectin-like ox-LDL receptor 1 (OLR1) to tumorigenesis. We analyzed microarray data from Olr1 knockout (KO) and wild type (WT) mice for genes involved in cellular transformation and evaluated effects of OLR1 over-expression in normal mammary epithelial cells (MCF10A) and breast cancer cells (HCC1143) in terms of gene expression, migration, adhesion and transendothelial migration. Twenty-six out of 238 genes were inhibited in tissues of OLR1 KO mice; the vast majority of OLR1 sensitive genes contained NF-κB binding sites in their promoters. Further studies revealed broad inhibition of NF-kB target genes outside of the transformation-associated gene pool, with enrichment themes of defense response, immune response, apoptosis, proliferation, and wound healing. Transcriptome of Olr1 KO mice also revealed inhibition of de novo lipogenesis, rate-limiting enzymes fatty acid synthase (Fasn), stearoyl-CoA desaturase (Scd1) and ELOVL family member 6 (Elovl6), as well as lipolytic phospholipase A2 group IVB (Pla2g4b). In studies comparing MCF10A and HCC1143, the latter displayed 60% higher OLR1 expression. Forced over-expression of OLR1 resulted in upregulation of NF-κB (p65) and its target pro-oncogenes involved in inhibition of apoptosis (BCL2, BCL2A1, TNFAIP3) and regulation of cell cycle (CCND2) in both cell lines. Basal expression of FASN, SCD1 and PLA2G4B, as well as lipogenesis transcription factors PPARA, SREBF2 and CREM, was higher in HCC1143 cells. Over-expression of OLR1 in HCC1143 cells also enhanced cell migration, without affecting their adherence to TNFα-activated endothelium or transendothelial migration. On the other hand, OLR1 neutralizing antibody inhibited both adhesion and transmigration of untreated HCC1143 cells. We conclude that OLR1 may act as an oncogene by activation of NF-kB target genes responsible for proliferation, migration and inhibition of apoptosis and de novo lipogenesis genes.

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Effects of OLR1 overexpression on transcription of                            genes involved in apoptosis, proliferation and lipogenesis in MCF10a and                            HCC1143 cells.These cells were transfected with either empty vector or                                OLR1 cDNA (Origene, Rockville, MD) using                            Lipofectamine 2000 (Invitrogen). Transfection efficiency                            (70–80%) was evaluated using GFP vector. RNA was extracted                            48 hours post-transfection, converted into cDNA and the expression of                            genes was determined by quantitative PCR. A. Efficiency of                            transfection (cells transfected with GFP vector). B.                            Quantitative PCR plot. Note the enhancement of OLR1 expression in both                            control and OLR1-transfected cultures in response to ox-LDL.                                C. Expression of genes involved in apoptosis and                            proliferation. In order to stimulate OLR1 associated                            signaling requiring OLR1-ligand interaction, OLR1                            transfected cells were treated with 40 µg/ml ox-LDL for 24 hours;                            graphs represent comparison with untreated control cells transfected                            with empty vector; D. Basal expression of                                OLR1, PLA2G4B and lipogenesis                            genes in normal human mammary epithelial cells (MCF10A) and breast                            cancer cells (HCC1143); E. Expression of                                OLR1, PLA2G4B and lipogenesis                            genes in MCF10a and HCC1143 cells transfected with OLR1 treated                            according to the protocol described above. F. Expression of                            lipogenesis transcription factors in MCF10a and HCC1143 cells                            transfected with OLR1 and treated according to the protocol described                            above. All experiments were conducted in triplicates. (*) p<0.05                            compared to respective control; (†) – p<0.05 compared to                            MCF10A.
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pone-0020277-g003: Effects of OLR1 overexpression on transcription of genes involved in apoptosis, proliferation and lipogenesis in MCF10a and HCC1143 cells.These cells were transfected with either empty vector or OLR1 cDNA (Origene, Rockville, MD) using Lipofectamine 2000 (Invitrogen). Transfection efficiency (70–80%) was evaluated using GFP vector. RNA was extracted 48 hours post-transfection, converted into cDNA and the expression of genes was determined by quantitative PCR. A. Efficiency of transfection (cells transfected with GFP vector). B. Quantitative PCR plot. Note the enhancement of OLR1 expression in both control and OLR1-transfected cultures in response to ox-LDL. C. Expression of genes involved in apoptosis and proliferation. In order to stimulate OLR1 associated signaling requiring OLR1-ligand interaction, OLR1 transfected cells were treated with 40 µg/ml ox-LDL for 24 hours; graphs represent comparison with untreated control cells transfected with empty vector; D. Basal expression of OLR1, PLA2G4B and lipogenesis genes in normal human mammary epithelial cells (MCF10A) and breast cancer cells (HCC1143); E. Expression of OLR1, PLA2G4B and lipogenesis genes in MCF10a and HCC1143 cells transfected with OLR1 treated according to the protocol described above. F. Expression of lipogenesis transcription factors in MCF10a and HCC1143 cells transfected with OLR1 and treated according to the protocol described above. All experiments were conducted in triplicates. (*) p<0.05 compared to respective control; (†) – p<0.05 compared to MCF10A.

Mentions: Transfection of MCF10A and HCC1143 cells with OLR1 expression vector resulted in 5 to 8-fold increase of OLR1 expression, which falls within the range OLR1 upregulation. In epithelial cells exposed to ox-LDL [18]. This led to modest upregulation of RELA (p65) and significant increases in RNA message for BCL2, BCL2A1, TNFAIP3 and CCND2 (Figure 3B). Compared to MCF10A cells, HCC1143 cells displayed increased basal levels of OLR1 (59%, p<0.05), FASN (24%, p<0.03), SCD1 (21%, p<0.01) and PLA2G4B (153%, p<0.01) (Figure 3C). The response from lipogenesis genes to OLR1 transfection varied in these cell lines (Figure 3D). In MCF10A cells, over-expression of OLR1 significantly stimulated transcription of SCD1 (37%, p<0.02), ELOVL6 (38%, p<0.05) and PLA2G4B (153%, p<0.02) concomitant with upregulation of CREM, whereas in HCC1143 cells CREM transcription declined and SCD1 and PLA2G4B were inhibited compared with control cultures transfected with empty vector.


Oxidized LDL receptor 1 (OLR1) as a possible link between obesity, dyslipidemia and cancer.

Khaidakov M, Mitra S, Kang BY, Wang X, Kadlubar S, Novelli G, Raj V, Winters M, Carter WC, Mehta JL - PLoS ONE (2011)

Effects of OLR1 overexpression on transcription of                            genes involved in apoptosis, proliferation and lipogenesis in MCF10a and                            HCC1143 cells.These cells were transfected with either empty vector or                                OLR1 cDNA (Origene, Rockville, MD) using                            Lipofectamine 2000 (Invitrogen). Transfection efficiency                            (70–80%) was evaluated using GFP vector. RNA was extracted                            48 hours post-transfection, converted into cDNA and the expression of                            genes was determined by quantitative PCR. A. Efficiency of                            transfection (cells transfected with GFP vector). B.                            Quantitative PCR plot. Note the enhancement of OLR1 expression in both                            control and OLR1-transfected cultures in response to ox-LDL.                                C. Expression of genes involved in apoptosis and                            proliferation. In order to stimulate OLR1 associated                            signaling requiring OLR1-ligand interaction, OLR1                            transfected cells were treated with 40 µg/ml ox-LDL for 24 hours;                            graphs represent comparison with untreated control cells transfected                            with empty vector; D. Basal expression of                                OLR1, PLA2G4B and lipogenesis                            genes in normal human mammary epithelial cells (MCF10A) and breast                            cancer cells (HCC1143); E. Expression of                                OLR1, PLA2G4B and lipogenesis                            genes in MCF10a and HCC1143 cells transfected with OLR1 treated                            according to the protocol described above. F. Expression of                            lipogenesis transcription factors in MCF10a and HCC1143 cells                            transfected with OLR1 and treated according to the protocol described                            above. All experiments were conducted in triplicates. (*) p<0.05                            compared to respective control; (†) – p<0.05 compared to                            MCF10A.
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Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3102697&req=5

pone-0020277-g003: Effects of OLR1 overexpression on transcription of genes involved in apoptosis, proliferation and lipogenesis in MCF10a and HCC1143 cells.These cells were transfected with either empty vector or OLR1 cDNA (Origene, Rockville, MD) using Lipofectamine 2000 (Invitrogen). Transfection efficiency (70–80%) was evaluated using GFP vector. RNA was extracted 48 hours post-transfection, converted into cDNA and the expression of genes was determined by quantitative PCR. A. Efficiency of transfection (cells transfected with GFP vector). B. Quantitative PCR plot. Note the enhancement of OLR1 expression in both control and OLR1-transfected cultures in response to ox-LDL. C. Expression of genes involved in apoptosis and proliferation. In order to stimulate OLR1 associated signaling requiring OLR1-ligand interaction, OLR1 transfected cells were treated with 40 µg/ml ox-LDL for 24 hours; graphs represent comparison with untreated control cells transfected with empty vector; D. Basal expression of OLR1, PLA2G4B and lipogenesis genes in normal human mammary epithelial cells (MCF10A) and breast cancer cells (HCC1143); E. Expression of OLR1, PLA2G4B and lipogenesis genes in MCF10a and HCC1143 cells transfected with OLR1 treated according to the protocol described above. F. Expression of lipogenesis transcription factors in MCF10a and HCC1143 cells transfected with OLR1 and treated according to the protocol described above. All experiments were conducted in triplicates. (*) p<0.05 compared to respective control; (†) – p<0.05 compared to MCF10A.
Mentions: Transfection of MCF10A and HCC1143 cells with OLR1 expression vector resulted in 5 to 8-fold increase of OLR1 expression, which falls within the range OLR1 upregulation. In epithelial cells exposed to ox-LDL [18]. This led to modest upregulation of RELA (p65) and significant increases in RNA message for BCL2, BCL2A1, TNFAIP3 and CCND2 (Figure 3B). Compared to MCF10A cells, HCC1143 cells displayed increased basal levels of OLR1 (59%, p<0.05), FASN (24%, p<0.03), SCD1 (21%, p<0.01) and PLA2G4B (153%, p<0.01) (Figure 3C). The response from lipogenesis genes to OLR1 transfection varied in these cell lines (Figure 3D). In MCF10A cells, over-expression of OLR1 significantly stimulated transcription of SCD1 (37%, p<0.02), ELOVL6 (38%, p<0.05) and PLA2G4B (153%, p<0.02) concomitant with upregulation of CREM, whereas in HCC1143 cells CREM transcription declined and SCD1 and PLA2G4B were inhibited compared with control cultures transfected with empty vector.

Bottom Line: Further studies revealed broad inhibition of NF-kB target genes outside of the transformation-associated gene pool, with enrichment themes of defense response, immune response, apoptosis, proliferation, and wound healing.Forced over-expression of OLR1 resulted in upregulation of NF-κB (p65) and its target pro-oncogenes involved in inhibition of apoptosis (BCL2, BCL2A1, TNFAIP3) and regulation of cell cycle (CCND2) in both cell lines.We conclude that OLR1 may act as an oncogene by activation of NF-kB target genes responsible for proliferation, migration and inhibition of apoptosis and de novo lipogenesis genes.

View Article: PubMed Central - PubMed

Affiliation: Department of Internal Medicine, College of Medicine, and the Central Arkansas Veterans Healthcare System, Little Rock, Arkansas, United States of America. mkhaidakov@uams.edu

ABSTRACT
Recent studies have linked expression of lectin-like ox-LDL receptor 1 (OLR1) to tumorigenesis. We analyzed microarray data from Olr1 knockout (KO) and wild type (WT) mice for genes involved in cellular transformation and evaluated effects of OLR1 over-expression in normal mammary epithelial cells (MCF10A) and breast cancer cells (HCC1143) in terms of gene expression, migration, adhesion and transendothelial migration. Twenty-six out of 238 genes were inhibited in tissues of OLR1 KO mice; the vast majority of OLR1 sensitive genes contained NF-κB binding sites in their promoters. Further studies revealed broad inhibition of NF-kB target genes outside of the transformation-associated gene pool, with enrichment themes of defense response, immune response, apoptosis, proliferation, and wound healing. Transcriptome of Olr1 KO mice also revealed inhibition of de novo lipogenesis, rate-limiting enzymes fatty acid synthase (Fasn), stearoyl-CoA desaturase (Scd1) and ELOVL family member 6 (Elovl6), as well as lipolytic phospholipase A2 group IVB (Pla2g4b). In studies comparing MCF10A and HCC1143, the latter displayed 60% higher OLR1 expression. Forced over-expression of OLR1 resulted in upregulation of NF-κB (p65) and its target pro-oncogenes involved in inhibition of apoptosis (BCL2, BCL2A1, TNFAIP3) and regulation of cell cycle (CCND2) in both cell lines. Basal expression of FASN, SCD1 and PLA2G4B, as well as lipogenesis transcription factors PPARA, SREBF2 and CREM, was higher in HCC1143 cells. Over-expression of OLR1 in HCC1143 cells also enhanced cell migration, without affecting their adherence to TNFα-activated endothelium or transendothelial migration. On the other hand, OLR1 neutralizing antibody inhibited both adhesion and transmigration of untreated HCC1143 cells. We conclude that OLR1 may act as an oncogene by activation of NF-kB target genes responsible for proliferation, migration and inhibition of apoptosis and de novo lipogenesis genes.

Show MeSH
Related in: MedlinePlus