Pre-treatment of HT-29 cells with 5-LOX inhibitor (MK-886) induces changes in cell cycle and increases apoptosis after photodynamic therapy with hypericin

Potency of non-steroidal anti-inflammatory drugs in chemotherapy

“…COX-2 was found to be involved in the regulation of P-gp, MRP1 and BCRP transporter expression via the COX-2/PGE2̸PGE receptor 4̸phosphatidyl inositol 3-kinase pathway (116,118). Synergistic effects of NSAIDs with hypericin (HY)-mediated photodynamic therapy (PDT) have also been reported (119)(120)(121)(122). The specific inhibition of COX, LOX and CYP450 activity increased the efficacy of HY-PDT in the HT-29 cancer cell line (121).…”

Effects of MK‐886, a leukotriene synthesis inhibitor, on [Ca2+]i and apoptosis in MG63 human osteosarcoma cells

“…MK-886 increased GluR1 phosphorylation in neuronal cultures in vitro and in the mouse cortex in vivo [Imbesi et al, 2007] and to inhibit the peroxisomeproliferator-activated receptor (PPAR)a [Kehrer et al, 2001]. MK-886 was thought to cause cell death in different cell types, such as enhancing N-acetylcysteine-induced apoptosis in Jurkat T lymphocytes [Deshpande and Kehrer., 2006], inducing changes in cell cycle and increased apoptosis after photodynamic therapy with hypericin in HT-29 cells [Kleban et al, 2006]; enhancing tumor necrosis factor-a-induced differentiation and apoptosis in HL-60 cells [Stika et al, 2006]; inducing apoptosis in gastric cancer through upregulation of p27kip1 and bax [Fan et al, 2004]; inducing apoptosis independently of 5-LO [Datta et al, 1999]; and activating voltage-gated and Ca…”

“…In osteoblastic cells, Babich et al [1997] [Chang et al, 2005], 4,4 0 -dithiodipyridine [Kuo et al, 2003], CP55,940 [Lu et al, 2002b], and tamoxifen [Lu et al, 2002a]. Additionally, it appears that phospholipase C-dependent pathways did not play a role in MK-886-induced Ca MK-886 is cytotoxic in several cell types including Jurkat T lymphocytes [Deshpande and Kehrer., 2006], HT-29 cells [Kleban et al, 2006], HL-60 cells [Stika et al, 2006], gastric cancer cells [Fan et al, 2004], and rat arterial myocytes [Smirnov et al, 1998]. As lasting [Ca 21 ] i rises may lead to cell death [Annunziato et al, 2003], it is interesting to know whether MK-886-induced [Ca 21 ] i increases cause cell death in MG63 cells, given that [Ca 21 ] i rises are observed prior to MK-886-induced apoptosis in Bcl-2-positive U937 cells [Anderson et al, 2002[Anderson et al, , 2004.…”

Rapid and efficient purification of naphthodianthrones from St. John's wort extract by using liquid–liquid extraction and SEC

“…Among the characteristic constituents of H. perforatum are the naphthodianthrones, mainly represented by hypericin and pseudohypericin which have been the focus of extensive scientific research as important antiviral agents against a variety of viruses (herpes, murine cytomegalovirus, sindbis, hepatitis B, equine anemia, including the human immunodeficiency virus (HIV) [7]. Recently, H. perforatum naphthodianthrones have also been studied for their possible application in the photodynamic therapy of cancer [8]. The concentration of these constituents in the plant is particularly low, as mentioned above, varying from 0.01 to 0.03% and even in alcoholic or hydroalcoholic extracts it may reach up to 0.1 -0.4% [9].…”