Clinical efficacy and safety of beclomethasone dipropionate inhalation capsules inhaled by Cyclohaler compared with Becotide Rotacaps inhaled by Rotahaler.

The study was undertaken to compare the efficacy and safety of beclomethasone dipropionate inhalation powder inhaled by Rotahaler (Becotide Rotacaps, Glaxo Wellcome) and by Cyclohaler (Beclomethasone Cyclocaps, Pharmachemie). Both the Cyclohaler and the Rotahaler are single-dose dry powder inhalation devices for inhalation capsules. 182 asthma patients stabilized on inhaled beclomethasone dipropionate 800 micrograms daily, were randomly assigned to treatment with 800 micrograms beclomethasone dipropionate inhaled by Rotahaler (91 patients) or Cyclohaler (91 patients) in a double-blind manner, using the double-dummy method. It was shown that the asthma remained stable during the 16-week study period with both preparations. There were no statistically significant differences in the pulmonary parameters (morning PEF, evening PEF, FEV1). The test/reference ratio of the morning PEF (99.5%, CI 93.0% - 106.5%) was well within the equivalence interval, which had been set a priori from 85% to 117.6%. There were no marked differences between the Cyclocaps and Rotacaps group in symptom scores and adverse events. A total of 12 patients had an asthma exacerbation: 8 exacerbations occurred in the Rotahaler group and 4 in the Cyclohaler group. The difference was not statistically significant. The use of rescue medication was somewhat higher in the Rotahaler group, but the difference did not reach statistical significance. Significantly more patients (17 patients) withdrew from the study in the Rotahaler group than in the Cyclohaler group (5 patients). In conclusion, there was no difference in asthma control of patients treated with Beclomethasone Cyclocaps inhaled by Cyclohaler and Becotide Rotacaps inhaled by Rotahaler. Both preparations are therapeutically equivalent.

Inhibition of insulin- and insulin-like growth factor-I-stimulated growth of human breast cancer cells by 1,25-dihydroxyvitamin D3 and the vitamin D3 analogue EB1089.

1,25 Dihydroxyvitamin D3 (1,25-(OH)2D3) and a number of synthetic vitamin D3 analogues with low calcaemic activity, have been shown to inhibit breast cancer cell growth in vitro as well as in vivo. The purpose of the present study was to investigate a possible interaction of 1,25-(OH)2D3 and the vitamin D3 analogue EB1089 with the insulin-IGF-I regulatory system. The oestrogen receptor-positive MCF-7 human breast cancer cells used in this study are able to grow autonomously and their growth is stimulated by insulin. In order to avoid interference of IGF-binding proteins (IGF-BPs), we used an analogue of IGF-I, long R3 IGF-I, which stimulated MCF-7 cell growth similar to insulin. The growth stimulation by insulin and by long R3 IGF-I was completely inhibited by 1,25-(OH)2D3 and EB1089. Autonomous growth was also inhibited by 1,25-(OH)2D3 and EB1089. The analogue EB1089 was active at 50 times lower concentrations than 1,25-(OH)2D3. It was shown that growth inhibition was not achieved through downregulation of insulin and IGF-I binding after 48 h. Paradoxically, after prolonged treatment (8 days), an upregulation of insulin and IGF-I binding was observed. Two possible intracellular mediators of the insulin-IGF mitogenic signal are C-FOS and mitogen-activated protein (MAP) kinase. Insulin-induced C-FOS mRNA was inhibited by 1,25-(OH)2D3, suggesting that it could be involved in the growth inhibition by 1,25-(OH)2D3. MAP kinase activation appeared not to be involved in growth stimulation by both insulin and IGF-I. Together, the present study demonstrates that vitamin D3 compounds can block the mitogenic activity of insulin and IGF-I, which may contribute to their tumour suppressive activity observed in vivo.

Antiestrogens inhibit in vitro bone resorption stimulated by 1,25-dihydroxyvitamin D3 and the vitamin D3 analogs EB1089 and KH1060.

1,25-Dihydroxyvitamin D3 (1,25-(OH)2D3) has been shown to inhibit breast cancer cell growth both in vitro and in vivo. A major drawback is that high doses of 1,25-(OH)2D3 are needed which may result in undesirable side effects like the development of hypercalcemia and an increased risk of bone metastases due to the stimulation of bone resorption by 1,25-(OH)2D3. Several newly developed 1,25-(OH)2D3 analogs have a reduced calcemic activity, but their direct effects on bone resorption have not yet been examined. Presently, the antiestrogen tamoxifen is the most important endocrine therapy for breast cancer. Recent studies have demonstrated the benefit of the combination tamoxifen and 1,25-(OH)2D3/analogs for the inhibition of breast cancer cell growth. Besides inhibition of breast cancer growth tamoxifen appeared to have beneficial effects on bone. The purpose of the present study was to investigate the effect of tamoxifen on 1,25-(OH)2D3- and analogs (EB1089 and KH1060)-stimulated bone resorption in an in vitro model. Bone resorption was stimulated by 1,25-(OH)2D3 and analogs in a dose-dependent manner with KH1060 and EB1089 being more potent and 1,25-(OH)2D3. Tamoxifen caused a strong dose-dependent inhibition (70% at 10 microM) of 1,25-(OH)2D3- and EB1089-stimulated bone resorption. KH1060-stimulated bone resorption was also inhibited by tamoxifen but to a lesser extent (36%). Also the pure antiestrogen ICI164,384 but not 17 beta-estradiol inhibited 1,25-(OH)2D3-stimulated bone resorption. Together, this study demonstrates that tamoxifen considerably reduces 1,25-(OH)2D3/analogs-stimulated bone resorption and therefore may be useful to reduce the risk of bone metastases. This together with the observed beneficial effects on breast cancer cell growth indicates that tamoxifen together with 1,25-(OH)2D3/analogs is an interesting combination for the treatment of breast cancer. The mechanism of the bone resorption inhibitory action is not yet known but seems to be independent of the estrogen pathway.

Inhibition of breast cancer cell growth by combined treatment with vitamin D3 analogues and tamoxifen.

The steroid hormone 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] has potential to be used as an antitumor agent, but its clinical application is restricted by the strong calcemic activity. Therefore, new vitamin D3 analogues are developed with increased growth inhibitory and reduced calcemic activity. In the present study, we have examined the antiproliferative effects of four novel vitamin D3 analogues (CB966, EB1089, KH1060, and 22-oxa-calcitriol) on breast cancer cells, either alone or in combination with the antiestrogen tamoxifen. The estrogen-dependent ZR-75-1 and estrogen-responsive MCF-7 cell lines were used as a model. It was shown that, with EB1089 and KH1060, the same growth inhibitory effect as 1,25-(OH)2D3 could be reached at up to 100-fold lower concentrations, whereas CD966 and 22-oxa-calcitriol were nearly equipotent with 1,25-(OH)2D3. The growth inhibition by the vitamin D3 compounds could be augmented by combined treatment with tamoxifen. At the maximal effective concentrations of the vitamin D3 compounds, the effect of combined treatment was addictive (MCF-7 cells) or less than additive (ZR-75-1 cells). Tamoxifen increased the sensitivity of the cells to the vitamin D3 compounds 2- to 4000-fold, which was expressed by a shift to lower median effective concentration values. Thereby, the vitamin D3 compounds may be used at even lower dosages in combination therapy with tamoxifen. A major problem of tamoxifen therapy is the development of tamoxifen resistance. We have observed that tamoxifen-resistant clones of ZR-75-1 cells retain their response to the vitamin D3 compounds. Regulation of the growth-related oncogene c-myc (mRNA level) and the estrogen receptor (protein level) were studied but appeared not to be related to the antiproliferative action of the vitamin D3 compounds. Together, our data point to a potential benefit of combination therapy with 1,25-(OH)2D3 or vitamin D3 analogues and tamoxifen for the treatment of breast cancer.

Transforming growth factor beta-induced dissociation between vitamin D receptor level and 1,25-dihydroxyvitamin D3 action in osteoblast-like cells.

In the present study the interaction between a locally produced factor in bone, transforming growth factor beta (TGF beta) and a systemic regulator of bone metabolism, 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) was investigated. In rat (UMR 106, ROS 17/2.8) and human (MG-63) osteoblastic cell lines and in isolated fetal rat osteoblasts TGF beta caused a comparable increase in vitamin D receptor (VDR) level. A maximum was observed after 6 h at 1 ng/ml TGF beta. Scatchard analysis revealed that up-regulation of VDR is due to an increase in receptor number and not to a change in affinity. This was supported by Northern blot analysis which showed a dose- and time-dependent increase in VDR mRNA by TGF beta. To assess the significance of the TGF beta-induced increase in VDR level for 1,25-(OH)2D3 effects cells were preincubated with TGF for 4 h (causing a 2-3-fold increase of the VDR level) and subsequently incubated with 1,25-(OH)2D3 for 4 h and 24 h. TGF beta preincubation potently inhibited subsequent 1,25-(OH)2D3 stimulation of osteocalcin production in both ROS 17/2.8 and MG-63 cells on protein as well as mRNA level. A similar inhibition by TGF beta was observed on the 1,25-(OH)2D3-induced increase in osteopontin mRNA. The current study demonstrates dissociation between regulation of VDR level and modulation of two 1,25-(OH)2D3 biological responses by TGF beta in osteoblast-like cell lines of different origin. This dissociation shows that, besides interaction at VDR level also at other levels in the cell interaction(s) exist between TGF beta and 1,25-(OH)2D3. Besides, these data emphasize the potential importance of the interplay of locally produced factors and systemic calciotrophic hormones in the regulation of bone metabolism.

Combined effects of 1,25-dihydroxyvitamin D3 and tamoxifen on the growth of MCF-7 and ZR-75-1 human breast cancer cells.

In the present study we assessed the effect of combined treatment with 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) and tamoxifen (TAM) on the growth of estrogen-responsive (MCF-7) and estrogen-dependent (ZR-75-1) human breast cancer cells. Both basal and 17 beta-estradiol (17 beta-E2)-stimulated growth were studied. 1,25-(OH)2D3 (10(-10)-10(-7) M) time- and dose-dependently inhibited basal growth of MCF-7 cells, with growth arrest at 10(-7) M. Also, 17 beta-E2-stimulated growth of MCF-7 and ZR-75-1 cells was inhibited by 1,25(OH)2D3 in a time- and dose-dependent manner. TAM inhibited 17 beta-E2-stimulated growth of both cell lines and at high concentration (10(-6) M) it also inhibited basal growth of MCF-7 cells. 10(-6) M TAM together with 1,25-(OH)2D3 resulted n a further inhibition of basal (MCF-7 cells) as well as 17 beta-E2-stimulated proliferation (MCF-7 and ZR-75-1 cells) compared to the inhibition by these agents alone. TAM in combination with 10(-7) M 1,25-(OH)2D3 resulted in growth arrest of 17 beta-E2-stimulated growth of MCF-7 cells. The inhibition of basal and 17 beta-E2-stimulated growth of MCF-7 cells was additive at early time points (4 days), but less than additive at later time points (8-10 days). It was demonstrated that with co-treatment of MCF-7 cells an equipotent inhibition of basal growth could be reached with lower concentrations of 1,25-(OH)2D3, compared to treatment with 1,25-(OH)2D3 alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Regulation of 1,25-dihydroxyvitamin D3 receptor gene expression by parathyroid hormone and cAMP-agonists.

We studied the effect of parathyroid hormone (PTH) and activation of the cAMP signal pathway on vitamin D receptor (VDR) mRNA levels in the phenotypically osteoblast cell line UMR 106. PTH caused a time- and dose-dependent increase of the VDR mRNA content with a maximum after 2 h. After 24 h the VDR mRNA level in PTH-treated cells returned to control level. In contrast, the 1,25-dihydroxyvitamin D3 (1,25(OH)2D3)-induced increase in VDR mRNA did not decline after 24 h. Inhibition of transcription with actinomycin D (10 micrograms/ml) completely abolished the PTH-induced increase of VDR mRNA and inhibition of translation with cycloheximide (1 microgram/ml) resulted in superinduction of VDR mRNA. The role of cAMP in the induction of VDR mRNA was studied with several agents acting via the cAMP pathway. Incubation for 2 and 4 h with forskolin, Bt2cAMP, PTHrP or prostaglandin E2 caused an increase in the level of VDR mRNA comparable to that caused by PTH. The calcium ionophore A23187 did not affect VDR mRNA level. The present study demonstrates that PTH and activation of the cAMP signal pathway cause up-regulation of VDR via induction of VDR gene expression. The effect of cAMP on the VDR gene is suggestive for a cAMP responsive element in the VDR gene.