Convergent synthesis, chiral HPLC, and vitamin D receptor affinity of analogs of 1,25-dihydroxycholecalciferol

A series of analogs of 1,25-dihydroxycholecalciferol was obtained with an additional chiral center at the terminus of the aliphatic side chain (C-25). The analogs were obtained from (+)-(R)- and (-)-(S)-2-methylglycidols, by opening of the oxirane ring with the carbanions derived from vitamin D C23a,24- or C22-sulfones. The diastereomeric purity of the analogs was determined by high-performance liquid chromatography on a chiral stationary phase. The binding affinity of analogs for the calf thymus intracellular vitamin D receptor (VDR) was two orders of magnitude lower than that of the lead compound of this group, 24a,24b-dihomo-1,25-dihydroxycholecalciferol, and it was comparable to the affinity of analogs of 24-nor-1,25-dihydroxycholecalciferol. However, a twofold difference was observed for analogs diastereomeric at C-25 in their affinity for VDR. The diastereodifferentiation of the binding affinity was found to be specific for vitamin D vicinal 25,26-diols as it disappears for analogs where 26-hydroxyl, neighboring the C-25 chiral center, is replaced with methyl.     

Synthesis and biological characterization of 1alpha,24,25-trihydroxy-2beta-(3-hydroxypropoxy)vitamin D(3) (24-hydroxylated ED-71)

24-Hydroxylated derivatives were synthesized in 24(R) and 24(S) forms by the convergent method as analogs related to 1alpha,25-dihydroxy-2beta-(3-hydroxypropoxy)vitamin D(3). In the convergent synthesis, the A-ring fragment, synthesized from diethyl D-tartarate, and the C/D-ring fragments in 24(R) and 24(S) forms (vitamin D numbering), obtained from vitamin D(2) via the Inhoffen-Lythgoe diol, were coupled in moderate yields to give 1alpha,24(R),25-trihydroxy-2beta-(3-hydroxypropoxy)vitamin D(3) and 1alpha,24(S),25-trihydroxy-2beta-(3-hydroxypropoxy)vitamin D(3). In preliminary biological evaluations, 24-hydroxylation of 1alpha,25-dihydroxy-2beta-(3-hydroxypropoxy)vitamin D(3) caused weakened affinity to vitamin D binding protein in vitro and less calcemic activity in vivo compared to the parent compound. While the affinity to vitamin D receptor in 24(R) epimer was sustained, the affinity in 24(S) epimer was less than that of the parent compound.     

Synthesis, antimalarial, antileishmanial, antimicrobial, cytotoxicity, and methemoglobin (MetHB) formation activities of new 8-quinolinamines

We report the synthesis, in vitro antiprotozoal (against Plasmodium and Leishmania), antimicrobial, cytotoxicity (Vero and MetHb-producing properties), and in vivo antimalarial activities of two series of 8-quinolinamines. N1-{4-[2-(tert-Butyl)-6-methoxy-8-quinolylamino]pentyl}-(2S/2R)-2-aminosubstitutedamides (21-33) and N1-[4-(4-ethyl-6-methoxy-5-pentyloxy-8-quinolylamino)pentyl]-(2S/2R)-2-aminosubstitutedamides (51-63) were synthesized in six steps from 6-methoxy-8-nitroquinoline and 4-methoxy-2-nitro-5-pentyloxyaniline, respectively. Several analogs displayed promising antimalarial activity in vitro against Plasmodium falciparum D6 (chloroquine-sensitive) and W2 (chloroquine-resistant) clones with high selectivity indices versus mammalian cells. The most promising analogs (21-24) also displayed potent antimalarial activity in vivo in a Plasmodium berghei-infected mouse model. Most interestingly, many analogs exhibited promising in vitro antileishmanial activity against Leishmania donovani promastigotes, and antimicrobial activities against a panel of pathogenic bacteria and fungi. Several analogs, notably 21-24, 26-32, and 60, showed less MetHb formation compared to primaquine indicating the potential of these compounds in 8-quinolinamine-based antimalarial drug development.     

Synthesis of side-chain homologated analogs of 1,25-dihydroxycholecalciferol and 1,25-dihydroxyergocalciferol

A novel synthesis of side-chain homologated analogs of vitamin D isomers has been described. The synthesis allows for the insertion of the double bond into the C-24 position of the side chain. The key synthetic step involves the coupling of a new C24-vitamin D synthon with the respective side-chain fragment. The method is illustrated by the preparation of (24E)-24,24a-dehydro-24,24-dihomo-1,25-dihydroxycholecalcife rol (1) and (24b R)- and (24b S)-24,24-dihomo-1,25-dihydroxyergocalciferols (2 and 3). Trans geometry of the newly formed double bond in the side chain was confirmed by high field nuclear magnetic resonance spectra.     

Mechanism of monoterpene cyclization: stereochemical aspects of the transformation of noncyclizable substrate analogs by recombinant (-)-limonene synthase, (+)-bornyl diphosphate synthase, and (-)-pinene synthase

The tightly coupled nature of the reaction sequence catalyzed by monoterpene synthases has prevented direct observation of the topologically required isomerization step leading from geranyl diphosphate to the presumptive, enzyme-bound, tertiary allylic intermediate linalyl diphosphate, which ultimately cyclizes to the various monoterpene skeletons. Previous experimental approaches using the noncyclizable substrate analogs 6,7-dihydrogeranyl diphosphate and racemic methanogeranyl diphosphate, in attempts to dissect the cryptic isomerization step from the normally coupled reaction sequence, were thwarted by the limited product available from native monoterpene synthases and by the inability to resolve chiral monoterpene products at the microscale. These approaches were revisited using three recombinant monoterpene synthases and chiral phase capillary gas chromatographic methods to separate antipodal products of the substrate analogs. The recombinant monoterpene olefin synthases, (-)-limonene synthase from spearmint and (-)-pinene synthase from grand fir, yielded essentially only achiral, olefin products (corresponding to the respective analogs and homologs of myrcene, trans-ocimene and cis-ocimene) from 6,7-dihydrogeranyl diphosphate and (2S,3R)-methanogeranyl diphosphate; no significant amounts of terpenols or homoterpenols were formed, nor was direct evidence obtained for the formation of the anticipated analog and homolog of the tertiary intermediate linalyl diphosphate (i.e., 6,7-dihydrolinalyl diphosphate and homolinalyl diphosphate, respectively). In the case of recombinant (+)-bornyl diphosphate synthase from common sage, the achiral olefins were generated, as before, from 6,7-dihydrogeranyl diphosphate and (2R,3S)-methanogeranyl diphosphate, but 6,7-dihydrolinalool and homolinalool also comprised significant components of the respective product mixtures, indicating greater access of water to the active site of this enzyme compared to the olefin synthases; again, no direct evidence for the production of 6,7-dihydrolinalyl diphosphate or homolinalyl diphosphate was obtained. Resolution of the terpenol products of (+)-bornyl diphosphate synthase, by chiral phase separation, revealed the predominant formation of (3R)-dihydrolinalool from dihydrogeranyl diphosphate and of (4S)-homolinalool from (2R,3S)-methanogeranyl diphosphate. The opposite stereochemistries of these products indicates water trapping from opposite faces of the corresponding tertiary carbocationic intermediates of the respective reactions, a phenomenon that appears to result from the binding conformations of these substrate analogs. Although these experiments failed to provide direct evidence for the tertiary intermediate of the tightly coupled isomerization-cyclization sequence, they did reveal a mechanistic difference between the olefin synthases and bornyl diphosphate synthase involving access of water as a participant in the reaction.     

Novel side chain analogs of 1alpha,25-dihydroxyvitamin D(3): design and synthesis of the 21,24-methano derivatives

The syntheses of the new 21,24-methano derivatives of 1alpha,25-dihydroxyvitamin D(3) [viz. 1(S),3(R)-dihydroxy-17(R)-(1',4'-cis-(4'-(1'-hydroxy-1'-methylethyl)-cyclo-hexyl))-9,10-seco-androsta-5(Z),7(E),10(19)-triene (MC 2108) and its (1',4'-trans)-isomer (MC 2110)] are described. The key step is the establishment, by Diels-Alder reaction on a CD-ring side chain diene intermediate prepared from vitamin D(2), of a 1,4-disubstituted cyclohexene moiety in the side chain. Hydrogenation to a 1:1 mixture of cis and trans cyclohexane derivatives and separation of the two series at a stage prior to the standard Horner-Wittig coupling with the (Hoffmann-La Roche) ring-A building block were other important steps in the syntheses of the target analogs. The relative configurations of intermediates were assigned by NMR spectroscopy. MC 2108 and MC 2110 are of interest as conformationally locked side chain derivatives to probe the receptor interactions of not only the parent vitamin D hormone but also its biologically active symmetrical 'double side chain' analog [21-(3'-hydroxy-3'-methylbutyl)-9,10-seco-cholesta-5(Z),7(E),10(19)-triene-1(S),3(R),25-triol (MC 2100)], 'both' side chains of which can formally be traced out in the new analogs. The preferred conformations, inferred from an analysis of (13)C-NMR characteristics, notably the chemical shift of C-17 in a series of analogs, to have the tertiary alcohol (1'-hydroxy-1'-methylethyl) substituent equatorial on the cyclohexane chair, are confirmed by molecular modeling.     

Stereoselective convergent synthesis of 24-substituted metabolites and analogues of vitamin D

The synthesis of vitamin D(3) active metabolites [24R,25-(OH)(2)-D(3), 24S,25-(OH)(2)-D(3) and 1alpha,24R,25-(OH)(3)-D(3)] and the first 24-aminovitamin D(3) derivatives [24S-benzoylamino-25-OH-D(3) and 24S-benzoylamino-1alpha,25-(OH)(2)-D(3)] are reported. The stereogenic center at C-24 was generated through ultrasonically induced aqueous conjugate addition of iodide 8 to dioxolanone 6 or oxazolidinone 7. The vitamin D triene system was constructed using the Lythgoe approach. The synthetic route, which is both short (6 or 7 steps from iodide 8) and efficient (32-45% overall yield), constitutes a practical method for the preparation of 24-functionalized metabolites and analogues of vitamin D(3). The ultrasonically induced conjugate addition in the key step provides a novel example of a highly stereoselective reaction promoted by the zinc-copper couple in aqueous media.     

Synthesis and antiproliferative activity of side-chain unsaturated and homologated analogs of 1,25-dihydroxyvitamin D(2). (24E)-(1S)-24-Dehydro-24a-homo-1,25-dihydroxyergocalciferol and congeners

A series of analogs of 1,25-dihydroxyergocalciferol (1-4) was synthesized and screened for their antiproliferative activity in vitro. The structure of new analogs was designed based on biological activity of the previously obtained side-chain modified analogs of vitamin D(2) and D(3). The analogs were obtained by the Julia olefination of C(22)-vitamin D sulfone 11 with side-chain aldehyde 15. The analogs were tested for their antiproliferative activity against the cells of human breast cancer lines T47D and MCF7 as well as human and mouse leukemia lines, HL-60 and WEHI-3, respectively. Analog 2 (PRI-1907) showed the strongest antiproliferative activity out of the present series of analogs of 1,25-dihydroxyvitamin D(2) with the mono homologated and double unsaturated side chain. The activity of 2 was 3-150 times stronger, depending on the cell line, than that of 1,25-dihydroxycholecalciferol (calcitriol), used as standard.     

Novel vitamin D3 derivatives, 26-homo-delta 22-dehydro-1 alpha,25(S)-dihydroxyvitamin D3 and 26-homo-delta 22-dehydro-1 alpha,25(R)-dihydroxyvitamin D3: preferential activity in c-myc mRNA production and in induction of phenotypic differentiation of HL-60 cells

Novel vitamin D3 derivatives, 26-homo-delta 22-1 alpha,25(S)-dihydroxyvitamin D3 and 26-homo-delta 22-1 alpha,25(R)-dihydroxyvitamin D3 were compared with the native hormone, 1,25-dihydroxyvitamin D3, and with other vitamin D3 derivatives, in inhibition of cell growth, induction of phenotypic differentiation, and c-myc mRNA reduction of HL-60 cells. The degree of inhibition in cell growth caused by 26-homo-delta 22-1 alpha,25(S)-(OH)2D3 was the greatest followed by 26-homo-delta 22-1 alpha,25(R)-(OH)2D3. The ability to reduce NBT was parallel to that to inhibit cellular proliferation. 26-homo-delta 22-1 alpha,25(S)-(OH)2D3, 26-homo-delta 22-1 alpha,25(R)-(OH)2D3, 24-homo-24-F2-1 alpha,25-(OH)2D3, and 1 alpha,24(R)-(OH)2-26-Cl-D3 were more active than 1 alpha,25-(OH)2D3 in the induction of OK-M1+ and OK-Mo-2+ HL-60 cells. Using two color flow cytometric analysis, the percentages of OK-M5(+)- and OK-DR(+)-HL-60 cells were 33% in the treatment with 26-homo-delta 22-1 alpha,25(S)-(OH)2D3 plus interferon-gamma (IFN-gamma) but 14% in the treatment with 1 alpha,25-(OH)2D3 plus IFN-gamma. 26-Homo-delta 22-1 alpha,25(S)-(OH)2D3 has an inhibitory effect on c-myc reduction in treated HL-60 cells. These results suggest that the novel vitamin D3 derivatives, 26-homo-delta 22-1 alpha,25(S)-(OH)2D3 and 26-homo-delta 22-1 alpha,25(R)-(OH)2D3, have preferential activity in inducing phenotypic differentiation and in inducing cell proliferation related c-myc mRNA activity.     

The effect of vitamin D analogs and of vitamin D-binding protein on lymphocyte proliferation

In the absence of vitamin D-binding protein (DBP), 1,25-(OH)2D3 at 10(-12) M significantly inhibited the [3H]thymidine incorporation in human lymphocytes during mixed lymphocyte cultures (MLC) or after phyto-hemaglutinin (PHA) stimulation. In the presence of a physiological concentration of DBP (5 x 10(-6) M), the concentration of 1,25-(OH)2D3 required for inhibition was 10(-10) M (for PHA-cultures) and 10(-9) M (for MLC). Several vitamin D analogs were compared for their inhibitory action on PHA stimulation. In the absence of DBP, the concentration necessary for 50% inhibition of [3H]thymidine incorporation ranged from 10(-12) M [1,25-(OH)2D3 and 24,24-F2-1,25-(OH)2D3], over 10(-10) M [1,24R, 25-(OH)3D3; 1,25S, 26-(OH)3D3 and 26,27-F6-1,25-(OH)2D3] and 10(-8) M [25 OHD3 and 24,25-(OH)2D3] to 10(-6) M [calcitriol-lactone]. This rank order correlates with the binding affinity of the various analogs to the cytoplasmic 1,25-(OH)2D3-receptor. DBP counteracted the inhibitory effect of all analogs and the degree of counteraction was directly proportional to the binding affinity between DBP and the vitamin D analog. DBP thus decreased the in vitro inhibitory action of 1,25-(OH)2D3 and its analogs on lymphocyte proliferation. Of all analogs tested, only 1,25-(OH)2D3 had a significant effect at a physiological concentration.     

The difference of biological activity among four diastereoisomers of 1 alpha,25-dihydroxycholecalciferol-26,23-lactone

All four possible diastereoisomers of 1 alpha,25-dihydroxycholecalciferol-26,23-lactone (1 alpha,25-(OH)2D3-26,23-lactone) were chemically synthesized and were compared to 1 alpha,25-dihydroxycholecalciferol (1 alpha,25(OH)2D3) in terms of their stimulation, in vivo, of intestinal calcium transport and mobilization of calcium from bone in vitamin D-deficient rats (the two classic vitamin D-mediated responses), and their relative binding to the chick intestinal cytosol receptor for 1 alpha,25-(OH)2D3. The receptor binding affinity results are expressed as relative competitive index (RCI), where the RCI is defined as 100 for 1 alpha,25(OH)2D3. The RCI obtained for 23(S)25(S)-1 alpha,25(OH)2D3-26,23-lactone was 7.90, for 23(R)25(R)-1 alpha,25(OH)2D3-26,23-lactone was 2.27, 23(S)25(R)-1 alpha,25(OH)2D3-26,23-lactone was 0.17, for 23(R)25(S)-1 alpha,25(OH)2D3-26,23-lactone 0.22 and for the in vivo produced 1 alpha,25(OH)2D3-26,23-lactone the RCI was only 0.17. Also the four diastereoisomers of 1 alpha,25(OH)2D3-26,23-lactone all stimulated intestinal calcium transport, reaching a maximum 8 h after administration. Compared with the stimulation of intestinal calcium transport by 1 alpha,25(OH)2D3, 23(S)25(S)-1 alpha,25(OH)2D3-26,23-lactone was 1/4 as effective, 23(R)25(R)-1 alpha,25(OH)2D3-26,23-lactone was 1/20 as effective, 23(S)25(R)-1 alpha,25(OH)2D3-26,23-lactone was 1/74 as effective and 23(R)25(S)-1 alpha,25(OH)2D3-26,23-lactone was 1/53 as effective. Similarly, 23(S)25(S)-1 alpha,25(OH)2D3-26,23-lactone and 23(R)25(R)-1 alpha,25(OH)2D3-26,23-lactone were estimated to be 3 and 20 times less active than 1 alpha,25-(OH)2D3 in elevation of serum calcium. However, 23(S)25(R)-1 alpha,25(OH)2D3-26,23-lactone and 23(R)25(S)-1 alpha,25(OH)2D3-26,23-lactone decreased the serum calcium levels 24 h after administration. 23(S)25(R)-1 alpha,25(OH)2D3-26,23-lactone reduced serum calcium concentrations to a greater extent than 23(R)25(S)-1 alpha,25(OH)2D3-26,23-lactone. These results indicate that the biological activities of the diastereoisomers of 1 alpha,25(OH)2D3-26,23-lactone were quite different among four stereochemical configurations.     

Synthesis, theoretical and structural analyses, and enantiopharmacology of 3-carboxy homologs of AMPA

We have previously used homologation of (S)-glutamic acid (Glu) and Glu analogs as an approach to the design of selective ligands for different subtypes of Glu receptors. (RS)-2-Amino-3-(3-carboxy-5-methyl-4-isoxazolyl)propionic acid (ACPA), which is an isoxazole homolog of Glu, is a very potent agonist at the (RS)-2-amino-3-(3-hydroxy-5-methyl-4-isoxazolyl)propionic acid (AMPA) subgroup of Glu receptors and a moderately potent ligand for the kainic acid (KA) subgroup of Glu receptors. The enantiomers of ACPA were previously obtained by chiral HPLC resolution. Prompted by pharmacological interest in ACPA, we have now prepared the (S)- and (R)-enantiomers of ACPA by stereocontrolled syntheses using (1R,2R,5R)- and (1S,2S,5S)-2-hydroxy-3-pinanone, respectively, as chiral auxiliaries. Furthermore, the 5-ethyl analog of ACPA, Ethyl-ACPA, was synthesized, and (S)- and (R)-Ethyl-ACPA were also prepared using this method. The absolute configurations of (S)- and (R)-ACPA were established by X-ray crystallographic analysis of a protected (1S,2S,5S)-2-hydroxy-3-pinanone imine derivative of (R)-ACPA. The absolute stereochemistry of (S)- and (R)-Ethyl-ACPA was assigned on the basis of a comparison of their properties with those of the enantiomers of ACPA, employing elution order on chiral HPLC columns, as well as circular dichroism (CD) spectroscopy in combination with time-dependent density functional theory. The structural and electronic basis for the Cotton effect observed for such analogs is examined. The lower homolog of ACPA, (RS)-2-amino-2-(3-carboxy-5-methyl-4-isoxazolyl)acetic acid (1), which is a Glu analog, was also synthesized. Affinities and neuroexcitatory effects were determined using rat brain membranes and cortical wedges, respectively, at native AMPA, KA, and N-methyl-D-aspartic acid (NMDA) receptors. The molecular pharmacology of (S)- and (R)-ACPA and (S)- and (R)-Ethyl-ACPA was evaluated at homomeric cloned subtypes of AMPA receptors (iGluR1o,3o,4o) and of KA receptors (iGluR5,6), expressed in Xenopus laevis oocytes. The cloned receptors mGluR1alpha, mGluR2, and mGluR4a, expressed in CHO cell lines, were used to study the effects of the five compounds at metabotropic Glu receptors. In accordance with ligand-receptor complexes known from X-ray crystallography, the conformationally restricted Glu analog 1 was inactive at all Glu receptors studied, and the R-forms of ACPA and Ethyl-ACPA were very weak or inactive at these receptors. At AMPA receptor subtypes, (S)-ACPA and (S)-Ethyl-ACPA showed equally potent agonist effects at iGluR1o and iGluR3o, whereas (S)-Ethyl-ACPA was 6-fold more potent than (S)-ACPA at iGluR4o. (S)-ACPA and (S)-Ethyl-ACPA were approximately an order of magnitude less potent at iGluR5 than at AMPA receptor subtypes, and neither compound showed detectable effects at iGluR6. The binding mode of (S)-Ethyl-ACPA at iGluR2 was examined by docking to the (S)-ACPA-iGluR2 complex.     

Synthesis of enantiomerically pure milnacipran analogs and inhibition of dopamine, serotonin, and norepinephrine transporters

A series of Milnacipran analogs with variation in the aromatic moiety were prepared in high enantiomeric excess. Structure-activity relationships for two parallel enantiomeric series are described. The (-)-(1R,2S)-naphthyl analog (8h) showed the highest potency in the two series and is a triple reuptake inhibitor of the SERT, NET, and DAT.     

2-(3'-Hydroxypropylidene)-1alpha-hydroxy-19-norvitamin D compounds with truncated side chains

Our recent studies with 2-(3'-hydroxypropylidene) analogs of 1alpha,25-dihydroxy-19-norvitamin D(3) showed that this 2-substituent creates compounds with very potent biological activity. In the continuing search for vitamin D compounds with selective activity profiles, we prepared a series of 1alpha-hydroxy-19-norvitamin D analogs characterized by the presence of a 3'-hydroxypropylidene substituent at C-2 and a truncated side chain. These vitamin D compounds were efficiently prepared using convergent syntheses. The C,D-fragments, namely the Grundmann ketones 19, 20, 27, 36 and 37 were synthesized from the known 8beta-benzoyloxy-22-aldehydes 12 and 29. These hydrindanones were subjected to Lythgoe type Wittig-Horner coupling with phosphine oxide 21, prepared by us previously, and after hydroxyl deprotection the set of 19-norvitamins 7-11 was successfully obtained. According to our expectations, all analogs (with an exception of the 20R-compound 7) have pronounced in vitro activity. When compared to the natural hormone 1alpha,25-(OH)(2)D(3) (1), they show the same or only slightly reduced affinity for the vitamin D receptor while being similarly effective as 1 in differentiation of HL-60 cells into monocytes.     

The effects of 1alpha,24(S)-dihydroxyvitamin D(2) analog on cancer cell proliferation and cytokine expression

It is well established that 1alpha,25-dihydroxyvitamin D(3) (1alpha,25(OH)(2)D(3)), the active metabolite of vitamin D, plays a role in regulating proliferation and differentiation of cells, in addition to its classic function in mineral homeostasis. Recent studies have also provided evidence for the involvement of 1alpha,25(OH)(2)D(3) in regulating the immune system. However, therapeutic application of 1alpha,25(OH)(2)D(3) to hyperproliferative diseases such as cancer, or for immunologic purposes, is thwarted by its hypercalcemic activity. In order to overcome this obstacle, analogs of 1alpha,25(OH)(2)D(3) have been produced that exhibit decreased hypercalcemic activity while retaining the growth and immunologic regulating properties. In the present study, the efficacy of 1alpha,24(S)-dihydroxyvitamin D(2) (1alpha,24(S)(OH)(2)D(2)), a vitamin D(2) analog, in restraining cell proliferation was compared to that of 1alpha,25(OH)(2)D(3). In parallel studies, cancer cell lines were grown in increased concentrations (10(-10)-10(-7) M) of each compound for various incubation periods (1-4 days). Growth was assessed by measuring [(3)H]thymidine incorporation. The results revealed that 1alpha,24(S)(OH)(2)D(2) significantly inhibits proliferation to an extent similar to that observed for 1alpha,25(OH)(2)D(3). Moreover, incubating the human leukemia cell line, HL-60, with 1alpha,24(S)(OH)(2)D(2) resulted in an induction of differentiation of these promyelomonocyte cells into monocyte-macrophage-like cells, in a manner similar to that observed with 1alpha,25(OH)(2)D(3). Using a Western procedure, it was also shown that 1alpha,24(S)(OH)(2)D(2) like 1alpha,25(OH)(2)D(3) enhances the expression of vitamin D receptors (VDR) in the rat osteosarcoma cell line, ROS 17/2.8. The expression of tumor necrosis factor (TNF) alpha (TNF-alpha) in human peritoneal macrophages (HPM) obtained from uremic patients treated with continuous ambulatory peritoneal dialysis (CAPD) was found to be regulated by 1alpha,25(OH)(2)D(3) as well as by 1alpha,24(S)(OH)(2)D(2). Incubations of HPM with 1alpha,25(OH)(2)D(3) or 1alpha,24(S)(OH)(2)D(2), have inhibited the expression of TNF-alpha on both mRNA and protein levels. These results suggest that 1alpha,25(OH)(2)D(3) has a role in controlling the rate of inflammation in the peritoneal cavity of CAPD treated patients. Since 1alpha,24(S)(OH)(2)D(2) does not cause hypercalcemia, the present results encourage the possible use of this vitamin D(2) analog in the treatment of cancer and hyper-inflammatory diseases.