Vitamin D analogs induce lipoxygenase mRNA expression and activity as well as reactive oxygen species (ROS) production in human bone cells

Vitamin D metabolites and analogs induce lipoxygenase mRNA expression and activity as well as reactive oxygen species (ROS) production in human bone cell line

“…We hypothesized that the growth modulating effects of vitamin D compounds in human osteoblasts might be associated with accelerated production of LO metabolites, whose putative action including effects on ROS production may explain some of the new links between the LO system and other biological activities [17]. This is a complementation of our data presented in the last 14th vitamin D workshop [9], which was on the effects of the vitamin D compounds on primary human female bone cells cultures, and using mainly the less calcemic analogs and not the natural metabolites.…”

“…Sub-confluent cultured cells were treated with vehicle, 25D at 50 nM; 1,25D at 25 nM; 24,25D at 125 nM; JKF or QW at 1 nM [14]; a. for 1 h with serum-free medium, followed by the addition of vehicle or vitamin D compounds at the concentrations mentioned above for 10 min and HETE were extracted and assayed as previously described [16] or; b. for 1 h by the addition of vehicle or vitamin D compounds, at the concentrations mentioned above for ROS assay as previously described [9] or; c. for 24 h with the addition of vehicle or vitamin D compounds, at the concentrations mentioned above for DNA synthesis (DNA) and for creatine kinase (CK) specific activity as previously described [13].…”

“…After hormonal treatment for 1 h, and ROS formation [9] using NBT colorimetric method as previously described [18] or for fluorescent microscopy by using 2 ,7 -dichloro-fluorescein diacetate (DCF) [19] was determined. …”

“…On the other hand 1,25D causes hypercalcemia [4,5] and therefore optimal bone growth and prevention of osteoporosis which requires its adequate concentrations [6,7], needs the use of the less-calcemic analogs having no adverse calcemic activity [8]. There are also other native metabolites of vitamin D such as the 24,25(OH) 2 D 3 (24,25D) and 25(OH)D 3 (25D) which are biologically active in the skeletal cells in addition to 1,25D, inducing changes in specific markers of osteoblasts in cultured osteoblasts [9,10] with no effect on calcium metabolism.…”

“…We also studied the involvement of LO, HETE and ROS in the stimulation of cell proliferation (DNA) and energy metabolism (CK). We focused on these enzymes since LO products [16] were shown to induce ROS formation [9], proliferation or survival, playing a role in promoting cell growth [13]. We hypothesized that the growth modulating effects of vitamin D compounds in human osteoblasts might be associated with accelerated production of LO metabolites, whose putative action including effects on ROS production may explain some of the new links between the LO system and other biological activities [17].…”