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L Binderup

Publications and source records attributed to L Binderup.

At least 73 records · Page 4Linked to original sources
PubMed1995

Studies on two new vitamin D analogs, EB 1089 and KH 1060: effects on bone resorption and osteoclast recruitment in vitro.

We have investigated the effects on bone resorption of two new potent antiproliferative vitamin D3 analogs, EB 1089 and KH 1060, by studying recruitment of osteoclasts in murine bone marrow cultures and 45Ca release from prelabeled neonatal mouse calvarial bones. Binding studies to vitamin D receptor protein, from human osteosarcoma MG-63 cells, demonstrated kd values of 8.5 x 10(-11) for 1 alpha,25(OH)2D3, 6.5 x 10(-11) for KH 1060, and 2.7 x 10(-10) for EB 1089. 1 alpha,25(OH)2D3 and EB 1089 were equipotent stimulators of osteoclast recruitment in murine bone marrow cultures, with EC50 at 10(-10) mol/L, whereas KH 1060 was about tenfold more potent with an EC50 at 10(-11) mol/L. In serum-free media, 1 alpha,25(OH)2D3 enhanced 45Ca release from neonatal mouse calvarial bones with EC50 at 10(-11) mol/L, but in the presence of 10% fetal calf serum (FCS) the stimulatory effect was significantly diminished, with a threshold value at 10(-10) mol/L. EB 1089 stimulated bone resorption with an estimated EC50 at 3 x 10(-11) mol/L, whereas KH 1060 was about tenfold more potent than 1 alpha,25(OH)2D3, and stimulated bone resorption with an EC50 at 10(-12) mol/L. The effects of EB 1089 and KH 1060 on 45Ca release were not significantly affected by the addition of 10% FCS. Addition of vitamin D binding protein to serum-free incubations of neonatal mouse calvarial bones, significantly inhibited the bone resorbing effect of 1 alpha,25(OH)2D3, but did not affect EB 1089 and KH 1060 induced 45Ca release.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

1 alpha,25-Dihydroxy-20-epi-vitamin D3: an extraordinarily potent inhibitor of leukemic cell growth in vitro.

We have evaluated seven recently synthesized vitamin D3 analogs for their abilities to inhibit clonal growth of leukemic cells, to induce leukemic cell differentiation, to stimulate clonal growth of normal myeloid committed stem cells, and to transactivate a reporter gene having a 1,25(OH)2D3 response element (VDRE). The 1,25(OH)2-20-epi-D3 showed extraordinary activity; at 10(-11) mol/L it inhibited clonal growth of 87% of HL-60 myeloblast cells, 60% of S-LB1 cells (human T-cell lymphotropic virus type 1 [HTLV-1]-immortalized human T-lymphocyte cell line) and 50% of leukemic clonogenic cells (colony-forming unit-leukemia) obtained from patients with acute myelogenous leukemia. No effect of either 1,25(OH)2D3 or 1,25(OH)2-20-epi-D3 was observed on the clonal proliferation of an HTLV-1-immortalized human T-lymphocyte cell line (Ab-VDR) having nonfunctional 1,25 (OH)2D3 cellular receptors (VDR). The abilities of 1,25(OH)2-20-epi-D3 to induce differentiation of HL-60 cells, as measured by generation of superoxide and nonspecific esterase production, was less than its antiproliferative activities. This analog stimulated colony-forming unit-granulocyte-macrophage growth from normal human bone marrow. To gain insights into the remarkable antileukemic activities of 1,25(OH)2-20-epi-D3, we examined its ability to enter HL-60 cells, bind to the VDR, and interact with a transfected VDRE attached upstream of a TK promoter-driven reporter gene (chloramphenicol acetyl transferase [CAT]). The 1,25(OH)2-20-epi-D3 potently increased CAT activity (> 16-fold, as compared with cells transfected with control receptor having no VDRE); paradoxically, 1,25(OH)2-20-epi-D3 was of equal potency to 1,25(OH)2D3 in transactivating the VDRE-containing reporter gene, even though the analog had a 1,000-fold greater antileukemic effect as compared with 1,25(OH)2D3. In summary, we have identified an extremely potent 1,25(OH)2D3 analog with antiproliferative and differentiating effects on leukemic cells and that may be clinically useful. This analog appears to generate biologic responses via the classical VDR pathway, but further studies are required to elucidate the mechanism by which this analog produces its prominent activities.

Calcitriol↗
PubMed1994

1 alpha,25-Dihydroxyvitamin D3 inhibits the invasive potential of human breast cancer cells in vitro.

Using the Boyden chamber invasion assay, the effect of 1 alpha,25-dihydroxyvitamin D3 [1 apha,25(OH)2D3] on the invasiveness of the highly invasive, oestrogen receptor-negative human breast cancer cell line MDA-MB-231 was examined. The MDA-MB-231 cells were shown to contain high-affinity receptors for 1 alpha,25(OH)2D3 with a Kd of 1.5 x 10(-11) M. When the cells were treated with 1 alpha,25(OH)2D3 for 4 days before the assay was performed, a dose-dependent inhibition of their invasive potential was demonstrated. Fifty per cent inhibition of invasion was obtained with a concentration of 13 pM of 1 alpha,25(OH)2D3. However, when the cells were treated for only 6 h during the assay, no inhibitory effect was seen. The process of migration was also affected by treatment with 1 alpha,25(OH)2D3 for 4 days, although the inhibition was not of the same magnitude as seen for the invasion. Fifty per cent inhibition of migration occurred at a concentration of 3.2 nM of 1 alpha,25(OH)2D3 (250 times higher than in the invasion assay). Inhibition of invasion and migration was not due to the known anti-proliferative effect of 1 alpha,25(OH)2D3, as no growth reduction could be demonstrated with treatment up to 5 days. Based on the present investigation it can therefore be concluded that 1 alpha,25(OH)2D3 is able to inhibit tumour cell invasiveness by a mechanism which is not exclusively based on its anti-proliferative and anti-migrative effects.

Adenocarcinoma↗
PubMed1994

The 1,25-dihydroxyvitamin D3 (VD) analogues MC903, EB1089 and KH1060 activate the VD receptor: homodimers show higher ligand sensitivity than heterodimers with retinoid X receptors.

The nuclear receptor for 1,25-dihydroxyvitamin D3 (VD), VDR, belongs to the nuclear receptor superfamily. This ligand-inducible transcription factor mediates the genomic VD signalling pathways by binding to specific response elements in the promoter region of VD regulated genes. Two types of natural VD response elements are used as models for the VDR-mediated transcriptional activation: one is bound by VDR-homodimers and is found in the human osteocalcin gene promoter, and the other is bound by heterodimers of VDR with retinoid X receptors (RXRs) as in the mouse osteopontin promoter. Here, we demonstrate that the VD analogues MC903, EB1089 and KH1060, previously shown to be potent regulators of proliferation and differentiation, are able to act as ligands for VDR and replace VD as a ligand in both nuclear signalling pathways. We found that they have different potency and sensitivity in their ability to stimulate the hormone-dependent promoter element. MC903 and EB1089 provide about 20% higher induction of gene activity than VD in a gene reporter system, whereas KH1060 was more sensitive, inducing transcription at about 100-fold lower doses than VD. Interestingly, VD and its analogues induce VDR homodimer-mediated gene activity at a 3- to 4-fold lower concentration than that of VDR-RXR heterodimers. This suggests that the ligand concentration is an additional regulatory level in the discrimination between signalling pathways involving homo- and heterodimeric hormone receptors.

Animals↗
PubMed1994

Effects of a new synthetic vitamin D analogue, EB1089, on the oestrogen-responsive growth of human breast cancer cells.

The anti-proliferative effects of the novel vitamin D analogue, EB1089, were assessed in the hormone-dependent breast cancer cell line, MCF-7, in vitro. In the present study, EB1089 was shown to be at least an order of magnitude more potent at inhibiting MCF-7 cell proliferation than the native hormone, 1 alpha,25-dihydroxyvitamin D3 (1,25(OH)2D3). Treatment of MCF-7 cell cultures with combinations of oestradiol and EB1089 ranging from 5 x 10(-11) M to 5 x 10(-9) M revealed the ability of EB1089 to suppress the mitogenic effects of oestradiol in these cells dose-dependently, as determined by [3H]thymidine incorporation and cell counts. EB1089 also exhibited a significant time- and dose-dependent decrease in MCF-7 oestrogen receptor (ER) concentration, as assessed by ligand binding assay. A fourfold reduction of ER levels by 5 x 10(-9) M EB1089 relative to control ER levels was observed, whilst 5 x 10(-9) M 1,25(OH)2D3 produced a significant but less dramatic decrease in ER levels. In addition, reduction of ER protein in EB1089-treated cell cultures was also demonstrated using an oestrogen receptor enzyme immunoassay. The interaction of EB1089 and anti-oestrogens on the oestradiol-stimulated growth of MCF-7 cells was investigated. The treatment of cell cultures with 5 x 10(-10) M EB1089 in combination with the pure anti-oestrogen, ICI 182,780 (5 x 10(-8) M), and in the presence of between 5 x 10(-10) M and 5 x 10(-9) M oestradiol, produced an augmented inhibition of MCF-7 cell proliferation compared with the actions of either compound alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Antineoplastic Agents↗
PubMed1994

Additive effects of calcipotriol and cyclosporine A: from in vitro experiments to in vivo applications in the treatment of severe psoriasis.

We report that calcipotriol (CPT) is a potent inhibitor of lymphocyte proliferation in mixed epidermal cell lymphocyte reactions. In this model, CPT and cyclosporine A (CsA) have synergistic effects. These results have led to a randomised double-blind therapeutic study protocol in patients with severe psoriasis. In these patients, topical CPT and sub-therapeutic doses of CsA (2mg/kg/d) induce disappearance of cutaneous lesions. This therapeutic association may minimize secondary side effects of both drugs.

Adult↗
PubMed1993

EB 1089, a novel vitamin D analogue, has strong antiproliferative and differentiation inducing effects on cancer cells.

EB 1089 is a novel vitamin D analogue which in vitro strongly inhibits the proliferation of U937 histiocytic lymphoma cells and MCF-7 breast cancer cells, with a potency of 50 to 100 times that of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3]. Studies of c-myc and c-fos expression in MCF-7 cells and of differentiation markers in U937 cells show that growth inhibition by EB 1089 is accompanied by induction of differentiation. The ability of EB 1089 to affect calcium metabolism in vivo in rats is decreased, compared to 1,25(OH)2D3. This low calcemic effect combined with the strong biological effect on cancer cells in vitro, makes EB 1089 an interesting candidate for treatment of cancer.

Animals↗
PubMed1993

Two novel vitamin D analogues, KH 1060 and CB 966, prolong skin allograft survival in mice.

KH 1060 and CB 966, two novel analogues of 1,25-dihydroxyvitamin D3(1,25(OH)2D3), were found to significantly delay the rejection of allogeneic skin grafts in CBA (H-2k) recipient mice, transplanted with skin from C57Bl/6 (H-2b) donor mice. Graft survival was assessed in mice treated with KH 1060 or CB 966 until the day of rejection, in comparison to mice treated with vehicle, 1,25(OH)2D3 or cyclosporin A (CsA). The mean graft survival time in days was found to be: 16.6 +/- 0.5 (CsA, 20 mg/kg/day orally (p.o.); 13.9 +/- 0.6 and 15.5 +/- 0.6 (1,25(OH)2D3, 0.2 and 0.4 microgram/kg/day intraperitoneally (i.p.)); 14.3 +/- 0.2 and 18.7 +/- 0.5 (CB 966, 0.2 and 0.4 microgram/kg/day i.p.); 13.7 +/- 0.8, 15.7 +/- 1.7, 18.2 +/- 2.7 and 24.5 +/- 0.5 (KH 1060, 0.02, 0.1, 0.2 and 0.4 microgram/kg/day i.p.). Mean graft survival in days for control mice was: 10.3 +/- 0.2 (vehicle for injection, i.p.) and 11.5 +/- 0.2 (olive oil, p.o.). Serum calcium levels, measured on the day of rejection, rose moderately after treatment with either KH 1060 or CB 966. Combination of CsA (20 mg/kg/day p.o.) with KH 1060 (0.1 microgram/kg/day i.p.) resulted in an additive or synergistic effect: 23.4 +/- 1.1 days of skin allograft survival, compared to 15.7 +/- 1.7 days with KH 1060 alone, and 15.1 +/- 1.9 days with CsA alone. KH 1060 was the most active of the tested compounds and can therefore be regarded as a potent immunosuppressor in transplantation; it can be used in combination with CsA and is effective at doses which only marginally affect serum calcium levels.

Animals↗
PubMed1993

Toxicity of vitamin D analogues in rats fed diets with standard or low calcium contents.

Sprague-Dawley rats were fed either a standard diet with 0.9/0.7% Ca/P or a semisynthetic low-calcium diet with 0.5/0.4% Ca/P and treated orally for 28 days with 1 alpha-hydroxycholecalciferol [1 alpha (OH)D3], a synthetic analogue of the physiologically active form of vitamin D3, 1 alpha,25-dihydroxycholecalciferol [1 alpha,25(OH)2D3], at dose levels of 0.2 and 2.0 micrograms kg/day. The high dose caused severe hypercalcaemia with retarded growth, nephrosis, and structural bone changes in rats fed the standard diet. The same dose caused only slight hypercalcaemia without growth retardation or bone changes, and only minimally affected the kidneys in rats fed the low-calcium diet. Hypercalcaemia with less pronounced pathological changes was found in the standard diet low-dose rats, whereas no hypercalcemia or pathological changes were found in the low-calcium diet low-dose group. The rats fed the low-calcium diet tolerated 1 alpha(OH)D3 at dose levels up to 10 times higher than rats on the standard diet. The use of diets low in calcium and low in phosphorus will thus allow the administration of higher dosages of vitamin D compounds without causing hypercalcaemia. This may permit a better evaluation of the pharmacologic and toxic effects not directly associated with the calcium-regulating properties of vitamin D metabolites and analogues.

Animals↗
PubMed1992

EB1089: a new vitamin D analogue that inhibits the growth of breast cancer cells in vivo and in vitro.

EB1089 is a novel vitamin D analogue which has been tested for its effects on breast cancer cell growth in vitro, using the established human breast cancer cell line MCF-7, and in vivo on the growth of established rat mammary tumours. Both EB1089 and 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) inhibited MCF-7 cell proliferation with the synthetic analogue being at least an order of magnitude more potent than the native hormone. In vivo anti-tumour effects were investigated using the N-methyl-nitrosourea-induced rat mammary tumour model. Oral treatment with EB1089 was tested at three doses. With the lower dose, significant inhibition of tumour growth was seen in the absence of a rise in serum calcium. The same dose of 1,25-(OH)2D3 had no effect on tumour growth but caused hypercalcaemia. With the higher dose of EB1089, striking tumour regression was seen although serum calcium rose. This report demonstrates that EB1089 possess enhanced anti-tumour activity coupled with reduced calcaemic effects relative to 1,25-(OH)2D3 and thus may have therapeutic potential as an anti-tumour agent.

Animals↗
PubMed1992

Synthesis and collagenase inhibition of new glycosides of aranciamycinone: the aglycon of the naturally occurring antibiotic aranciamycin.

Glycosides of aranciamycinone were prepared by glycosylation with sugar acetates and trimethylsilyl triflate in dichloromethane. Glycosides of the following sugars were prepared: alpha-L-rhamnopyranose, beta-D-glucopyranose, beta-D-ribopyranose, beta-D-xylopyranose, alpha-L-fucopyranose, 2-azido-2,6-dideoxy-alpha-L-mannopyranose, 2,6-dideoxy-alpha-L-arabino-hexopyranose, 3,6-dideoxy-alpha-L-arabino-hexopyranose, and 4,6-dideoxy-alpha-L-lyxo-hexopyranose. The new glycosides were tested for inhibition of Clostridium histolyticum collagenase and Yoshida Sarcoma tumor cells.

Animals↗
PubMed1992

Inhibition of collagenase by aranciamycin and aranciamycin derivatives.

Aranciamycin (1), an anthracycline antibiotic, was found to be an inhibitor of Clostridium histolyticum collagenase, with an IC50 = 3.7 x 10(-7) M. Elastase and trypsin were not inhibited at concentrations less than or equal to 10(-5) M. A number of aranciamycin derivatives 2-13 were prepared and tested for collagenase inhibition. While loss of activity was found for derivatives modified in the sugar ring or rings B and D of the aglycone, increased potency was found when the tertiary alcohol at C-9 was esterified. All compounds 1-13 were found to inhibit DNA synthesis of Yoshida sarcoma tumor cells.

Animals↗
PubMed1992

Immunological properties of vitamin D analogues and metabolites.

This commentary has attempted to describe some of the new aspects of our knowledge of the immunological properties of 1 alpha,25(OH)2D3, the physiologically active metabolite of vitamin D3, and its new analogues. These analogues will, in the future, serve as tools to increase our understanding of the role of vitamin D in immunobiology, not only in basal research but also, hopefully, in the therapy of immune-mediated diseases.

Animals↗
PubMed1992

Disodium 1-hydroxy-3-(1-pyrrolidinyl)-propylidene-1,1-bisphosphonate (EB-1053) is a potent inhibitor of bone resorption in vitro and in vivo.

The ability of the new nitrogen-containing bisphosphonate disodium-1-hydroxy-3-(1-pyrrolidinyl)-propylidene-1,1-bisphosphona te (EB-1053) to inhibit osteoclastic resorption was examined in vitro and in vivo. Results were compared to those obtained with 3-amino-1-hydroxypropylidene-1,1-bisphosphonate (pamidronate or APD). In vitro, when tested in osteoclast precursor-dependent systems (fetal mouse metacarpals and a coculture system), EB-1053 suppressed 45Ca release effectively and was found to be about 10 times more potent than pamidronate (ED50 = 2.5 x 10(-7) versus 2.5 x 10(-6) M, respectively). The EB-1053-inhibited osteoclastic resorption could be reversed by treatment with parathyroid hormone (PTH). In vivo, daily subcutaneous injections of EB-1053 to young growing rats for 7 days increased metaphyseal bone mass in tibiae dose dependently. In these experiments EB-1053 was about 50 times more potent than pamidronate. These studies show that EB-1053 is a very potent bisphosphonate that has potential use in the treatment of skeletal disorders.

Acid Phosphatase↗
PubMed1991

MC903, an analogue of 1,25-dihydroxyvitamin D3, increases the synthesis of nerve growth factor.

The effect of MC903, an analogue of 1,25-dihydroxyvitamin D3, on the expression of the nerve growth factor (NGF) gene has been studied in L cells. MC903 induces an increase in both NGF mRNA and protein with a time course similar to that obtained with 1,25-dihydroxyvitamin D3. This finding points to the potential importance of 1,25-dihydroxyvitamin D3 derivatives in the treatment of NGF-sensitive disorders.

Animals↗
PubMed1991

20-epi-vitamin D3 analogues: a novel class of potent regulators of cell growth and immune responses.

The 20-epi-vitamin D3 analogues are a novel class of vitamin D3 derivatives, structurally related to 1 alpha,25-dihydroxycholecalciferol (1 alpha,25(OH)2D3). They are characterized by an altered stereochemistry at carbon 20 in the side-chain. In vitro, these new analogues were found to be considerably more potent as regulators of growth and differentiation in the human histiocytic lymphoma cell line U 937 than 1 alpha,25(OH)2D3, despite a practically unchanged calcemic activity in vivo. The most potent analogue, KH 1060, inhibited cell proliferation by 50% at 10(-12) M (14,000 times more active than 1 alpha,25(OH)2D3). At the same time, KH 1060 induced cell differentiation at concentrations as low as 10(-14)M. In addition, the 20-epi-vitamin D3 analogues were found to be very potent inhibitors of T-lymphocyte proliferation induced by interleukin-1 or alloantigen. In this respect, they were several orders of magnitude more active than the potent immunosuppressive agent cyclosporin A (CyA). KH 1060, the most potent analogue, inhibited interleukin-1-induced mouse thymocyte proliferation by 50% at 3 x 10(-16) M and allogeneic stimulation of mouse spleen lymphocytes at 5 x 10(15) M. These effects were considered to be mediated by inhibition of interleukin-2 release from activated T-lymphocytes. The new analogues are of potential interest in the prevention of graft rejection and in the treatment of psoriasis, cancer and auto-immune diseases.

Calcitriol↗