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25-Hydroxycholesterol exerts both a cox-2-dependent transient proliferative effect and cox-2-independent cytotoxic effect on bovine endothelial cells in a time- and cell-type-dependent manner.

Nguyen VP, Chen SH, Pizzuto K, Cantarutti A, Terminesi A, Mendonca C, Dumont DJ - J Angiogenes Res (2010)

Bottom Line: These results suggest that some effects of 25-OHC on cells may be dependent on Cox-2 enzymatic activity.Cox-2 dependent elevating effects of 25-OHC on endothelial cell proliferation was transient.The lack of uniform response by the three endothelial cell types examined suggests that our model system of primary cultures of bmLECs, bmVECs, and bmAECs may aid the evaluation of celecoxib in inhibiting proliferation of different types of tumour-associated endothelial cells.

View Article: PubMed Central - HTML - PubMed

Affiliation: Molecular and Cellular Biology Research, Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, ON, M4N 3M5, Canada. dan.dumont@sri.utoronto.ca.

ABSTRACT

Background: 25-hydroxycholesterol (25-OHC) is a product of oxidation of dietary cholesterol present in human plasma. 25-OHC and other oxidized forms of cholesterol are implicated in modulating inflammatory responses involved in development of atherosclerosis and colon carcinogenesis.

Methods: Primary lymphatic, venous and arterial endothelial cells isolated from bovine mesentery (bmLEC, bmVEC, bmAEC) were treated with 25-OHC and tested for several different cellular parameters.

Results: We found 25-OHC to be a potent inducer of cyclooxygenase-2 (Cox-2, prostaglandin G-H synthase-2) expression in bovine mesenteric lymphatic, venous, and arterial endothelial cells. The induction of Cox-2 expression in endothelial cells by 25-OHC led to an initial increase in cellular proliferation that was inhibited by the Cox-2 selective inhibitor celecoxib (Celebrex). Prolonged exposure to 25-OHC was cytotoxic. Furthermore, endothelial cells induced to express Cox-2 by 25-OHC were more sensitive to the effects of the Cox-2 selective inhibitor celecoxib (Celebrex). These results suggest that some effects of 25-OHC on cells may be dependent on Cox-2 enzymatic activity.

Conclusions: Cox-2 dependent elevating effects of 25-OHC on endothelial cell proliferation was transient. Prolonged exposure to 25-OHC caused cell death and enhanced celecoxib-induced cell death in a cell-type dependent manner. The lack of uniform response by the three endothelial cell types examined suggests that our model system of primary cultures of bmLECs, bmVECs, and bmAECs may aid the evaluation of celecoxib in inhibiting proliferation of different types of tumour-associated endothelial cells.

No MeSH data available.


Related in: MedlinePlus

Expression of Cox2 in mesenteric ECs. A/ 25-OHC exposure induced Cox-2 expression in bmECs. ECs were treated with 25 μM of 25-OHC added directly to culture media and left overnight before mRNA harvest and RT-PCR. BmLECs and bmAECs expressed Cox-2 in the presence of 25-OHC but not in EtOH vehicle alone. Cox-1, however, was constitutively expressed in all three cell types. Basal level of Cox-2 was high in bmVECs but not in bmAECs or bmLECs. Cox-2 levels increased significantly upon treatment of bmVECs with 25-OHC. B/ 25-OHC exposure changed morphology cultured bmECs. ECs lost the typical endothelial cobble-stoned morphology and became elongated, forming partial swirls in the presence of 25-OHC but not in vehicle control.
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Figure 1: Expression of Cox2 in mesenteric ECs. A/ 25-OHC exposure induced Cox-2 expression in bmECs. ECs were treated with 25 μM of 25-OHC added directly to culture media and left overnight before mRNA harvest and RT-PCR. BmLECs and bmAECs expressed Cox-2 in the presence of 25-OHC but not in EtOH vehicle alone. Cox-1, however, was constitutively expressed in all three cell types. Basal level of Cox-2 was high in bmVECs but not in bmAECs or bmLECs. Cox-2 levels increased significantly upon treatment of bmVECs with 25-OHC. B/ 25-OHC exposure changed morphology cultured bmECs. ECs lost the typical endothelial cobble-stoned morphology and became elongated, forming partial swirls in the presence of 25-OHC but not in vehicle control.

Mentions: As previously described by Wohlfeil and Campbell [15,16], 25-OHC stimulates expression of Cox-2 in cultured ECs. Wohlfeil and Campbell exposed bovine coronary arterial cells to a concentration of 10 μg/mL (25 μM) of 25-OHC for 48 hours. To determine whether 25-OHC similarly induces Cox-2 expression our bmLECs, bmVECs, and bmAECs, we treated ECs with 25 μM added directly to culture media and left overnight. By RT-PCR, bmLECs and bmAECs expressed Cox-2 in the presence of 25-OHC but not in ethanol (EtOH) vehicle alone. Cox-1, however, was constitutively expressed in all three cell types (Figure 1A). Interestingly, basal level of Cox-2 was high in bmVECs but not in bmAECs or bmLECs. Cox-2 levels increased significantly upon treatment of bmVECs with 25-OHC. Thus, these results corroborate those reported by Wohlfeil and Campbell [15,16].


25-Hydroxycholesterol exerts both a cox-2-dependent transient proliferative effect and cox-2-independent cytotoxic effect on bovine endothelial cells in a time- and cell-type-dependent manner.

Nguyen VP, Chen SH, Pizzuto K, Cantarutti A, Terminesi A, Mendonca C, Dumont DJ - J Angiogenes Res (2010)

Expression of Cox2 in mesenteric ECs. A/ 25-OHC exposure induced Cox-2 expression in bmECs. ECs were treated with 25 μM of 25-OHC added directly to culture media and left overnight before mRNA harvest and RT-PCR. BmLECs and bmAECs expressed Cox-2 in the presence of 25-OHC but not in EtOH vehicle alone. Cox-1, however, was constitutively expressed in all three cell types. Basal level of Cox-2 was high in bmVECs but not in bmAECs or bmLECs. Cox-2 levels increased significantly upon treatment of bmVECs with 25-OHC. B/ 25-OHC exposure changed morphology cultured bmECs. ECs lost the typical endothelial cobble-stoned morphology and became elongated, forming partial swirls in the presence of 25-OHC but not in vehicle control.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2991284&req=5

Figure 1: Expression of Cox2 in mesenteric ECs. A/ 25-OHC exposure induced Cox-2 expression in bmECs. ECs were treated with 25 μM of 25-OHC added directly to culture media and left overnight before mRNA harvest and RT-PCR. BmLECs and bmAECs expressed Cox-2 in the presence of 25-OHC but not in EtOH vehicle alone. Cox-1, however, was constitutively expressed in all three cell types. Basal level of Cox-2 was high in bmVECs but not in bmAECs or bmLECs. Cox-2 levels increased significantly upon treatment of bmVECs with 25-OHC. B/ 25-OHC exposure changed morphology cultured bmECs. ECs lost the typical endothelial cobble-stoned morphology and became elongated, forming partial swirls in the presence of 25-OHC but not in vehicle control.
Mentions: As previously described by Wohlfeil and Campbell [15,16], 25-OHC stimulates expression of Cox-2 in cultured ECs. Wohlfeil and Campbell exposed bovine coronary arterial cells to a concentration of 10 μg/mL (25 μM) of 25-OHC for 48 hours. To determine whether 25-OHC similarly induces Cox-2 expression our bmLECs, bmVECs, and bmAECs, we treated ECs with 25 μM added directly to culture media and left overnight. By RT-PCR, bmLECs and bmAECs expressed Cox-2 in the presence of 25-OHC but not in ethanol (EtOH) vehicle alone. Cox-1, however, was constitutively expressed in all three cell types (Figure 1A). Interestingly, basal level of Cox-2 was high in bmVECs but not in bmAECs or bmLECs. Cox-2 levels increased significantly upon treatment of bmVECs with 25-OHC. Thus, these results corroborate those reported by Wohlfeil and Campbell [15,16].

Bottom Line: These results suggest that some effects of 25-OHC on cells may be dependent on Cox-2 enzymatic activity.Cox-2 dependent elevating effects of 25-OHC on endothelial cell proliferation was transient.The lack of uniform response by the three endothelial cell types examined suggests that our model system of primary cultures of bmLECs, bmVECs, and bmAECs may aid the evaluation of celecoxib in inhibiting proliferation of different types of tumour-associated endothelial cells.

View Article: PubMed Central - HTML - PubMed

Affiliation: Molecular and Cellular Biology Research, Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, ON, M4N 3M5, Canada. dan.dumont@sri.utoronto.ca.

ABSTRACT

Background: 25-hydroxycholesterol (25-OHC) is a product of oxidation of dietary cholesterol present in human plasma. 25-OHC and other oxidized forms of cholesterol are implicated in modulating inflammatory responses involved in development of atherosclerosis and colon carcinogenesis.

Methods: Primary lymphatic, venous and arterial endothelial cells isolated from bovine mesentery (bmLEC, bmVEC, bmAEC) were treated with 25-OHC and tested for several different cellular parameters.

Results: We found 25-OHC to be a potent inducer of cyclooxygenase-2 (Cox-2, prostaglandin G-H synthase-2) expression in bovine mesenteric lymphatic, venous, and arterial endothelial cells. The induction of Cox-2 expression in endothelial cells by 25-OHC led to an initial increase in cellular proliferation that was inhibited by the Cox-2 selective inhibitor celecoxib (Celebrex). Prolonged exposure to 25-OHC was cytotoxic. Furthermore, endothelial cells induced to express Cox-2 by 25-OHC were more sensitive to the effects of the Cox-2 selective inhibitor celecoxib (Celebrex). These results suggest that some effects of 25-OHC on cells may be dependent on Cox-2 enzymatic activity.

Conclusions: Cox-2 dependent elevating effects of 25-OHC on endothelial cell proliferation was transient. Prolonged exposure to 25-OHC caused cell death and enhanced celecoxib-induced cell death in a cell-type dependent manner. The lack of uniform response by the three endothelial cell types examined suggests that our model system of primary cultures of bmLECs, bmVECs, and bmAECs may aid the evaluation of celecoxib in inhibiting proliferation of different types of tumour-associated endothelial cells.

No MeSH data available.


Related in: MedlinePlus