Dramatic Enhancement of Antagonistic Activity on Vitamin D Receptor: A Double Functionalization of 1α-Hydroxyvitamin D3 26,23-Lactones

The synthesis of novel vitamin D receptor antagonists, 24-methyl-1alpha-hydroxyvitamin D(3) 26,23-lactones, is reported. We found that the biological activities of the vitamin D(3) lactones were affected by the structure of the lactone part. Furthermore, introduction of a 2alpha-methyl group into the 24-methylvitamin D(3) lactones dramatically enhanced their anti-vitamin D activity. [reaction: see text]

Metabolism of 20-epimer of 1α,25-dihydroxyvitamin D3 by CYP24: species-based difference between humans and rats

The 20-epi form of 1alpha,25-dihydroxyvitamin D(3) (1alpha,25(OH)(2)-20-epi-D(3)) is expected as drugs for leukemia, other cancers or psoriasis, because it shows several-hundred fold enhanced ability to induce cell differentiation and growth inhibition than 1alpha,25-dihydroxyvitamin D(3) while its calcemic activity is only slightly elevated. In this study, we compared the human and rat CYP24-dependent metabolism of 1alpha,25(OH)(2)-20-epi-D(3) by using the Escherichia coli expression system. The HPLC and LC-MS analyses of the metabolites revealed that rat CYP24 converted 1alpha,25(OH)(2)-20-epi-D(3) to 25,26,27-trinor-1alpha(OH)-24(COOH)-20-epi-D(3) through 1alpha,24,25(OH)(3)-20-epi-D(3) and 1alpha,25(OH)(2)-24-oxo-20-epi-D(3). The binding affinity of trinor-1alpha(OH)-24(COOH)-20-epi-D(3) for vitamin D receptor (VDR) was less than 1/4000 of that of 1alpha,25(OH)(2)-20-epi-D(3). These results suggest that rat CYP24 can almost completely inactivate 1alpha,25(OH)(2)-20-epi-D(3). On the other hand, human CYP24 mainly converted 1alpha,25(OH)(2)-20-epi-D(3) to its putative demethylated compound with a hydroxyl group, via 1alpha,24,25(OH)(3)-20-epi-D(3), 1alpha,25(OH)(2)-24-oxo-20-epi-D(3), and 1alpha,23,25(OH)(3)-24-oxo-20-epi-D(3). All of these metabolites showed considerable affinity for vitamin D receptor. These results clearly demonstrate the species-based difference between human and rat on the CYP24-dependent metabolism of 1alpha,25(OH)(2)-20-epi-D(3).

Concise synthesis and biological activities of 2α-Alkyl- and 2α-(ω-Hydroxyalkyl)-20- epi -1α,25-dihydroxyvitamin D 3

We found a concise route to the Trost A-ring precursor enyne for synthesizing 2alpha-alkylated 1alpha,25-dihydroxyvitamin D(3) (1) from D-glucose. The enynes were coupled with the 20-epi-CD ring part to study the effect of the double modification of 2alpha-substitution and 20-epimerization upon biological activities of 1. The novel three analogues of 2alpha-alkyl- and four analogues of 2alpha-(omega-hydroxyalkyl)-20-epi-1alpha,25-dihydroxyvitamin D(3) (5b-d and 6a-d) showed higher binding affinity for vitamin D receptor (VDR) and more potent activity in induction of HL-60 cell differentiation than those of the natural hormone 1.

Efficient synthesis of 2-modified 1alpha,25-dihydroxy-19-norvitamin D3 with Julia olefination: high potency in induction of differentiation on HL-60 cells

Six novel 2-substituted analogues of 1alpha,25-dihydroxy-19-norvitamin D(3), 6a,b-8a,b, were efficiently synthesized utilizing (-)-quinic acid as the A-ring precursor. The C2-modified A-rings were prepared as 4-alkylated (3R,5R)-3,5-dihydroxycyclohexanones 12-15 from (-)-quinic acid based on radical allylation at the C4 position of methyl (-)-quinicate. The new type of the CD-ring coupling partner 23 was synthesized from 25-hydroxy Grundmann's ketone 19 to apply to the modified Julia olefination to construct a diene unit between the A-ring and the CD-ring. The coupling yields, including a deprotection step, were 47-62%. After the separation of the diastereomers based on C2 stereochemistry, the structure (2alpha or 2beta) was determined by (1)H NMR experiments and compared to DeLuca's 2-methyl- and 2-ethyl-1alpha,25-dihydroxy-19-norvitamin D(3). Thus, the synthesized 2alpha-(3-hydroxypropyl)-1alpha,25-dihydroxy-19-norvitamin D(3) (8a) showed almost the same potency in binding to the bovine thymus vitamin D receptor (VDR) as the natural hormone 1, while its beta-isomer 8b had only a 3% affinity. Both 2alpha-allyl- and 2alpha-propyl-1alpha,25-dihydroxy-19-norvitamin D(3) (6a and 7a) and their 2beta-analogues (6b and 7b) possessed a weak affinity for the VDR. The strong VDR ligand 8a was ca. 36-fold more potent in induction of HL-60 cell differentiation than 1, and interestingly, even the weaker ligand 8b showed a 6.7-fold higher potency in the cell differentiation activity than that of 1.

Design and synthesis of potent vitamin D receptor antagonists with A-ring modifications: remarkable effects of 2alpha-methyl introduction on antagonistic activity

Novel A-ring analogues of the vitamin D receptor (VDR) antagonist (3a), ZK-159222, and its 24-epimer (3b) were convergently synthesized. Preparation of the CD-ring portions with the side chains of 3a,b, followed by palladium-catalyzed cross-coupling with the A-ring enyne precursors (15a,b), (3S,4S,5R)- and (3S,4S,5S)-bis[(tert-butyldimethylsilyl)oxy]-4-methyloct-1-en-7-yne, afforded the 2alpha-methyl-introduced analogues (4a,b) and their 3-epimers (5a,b). The biological profiles of the hybrid analogues were assessed in terms of affinity for VDR, and antagonistic activity to inhibit HL-60 cell differentiation induced by the natural hormone, 1alpha,25-dihydroxyvitamin D(3). The analogue 4a showed an approximately fivefold higher antagonistic activity compared with 3a. The 2alpha-methyl introduction into 3a increased the receptor affinity, thereby enhancing VDR antagonism. This approach to design potent antagonists based on hybridization of structural motifs in the A-ring and in the side chain may prove to be valuable.

Synthesis of 2,2-dimethyl-1,25-dihydroxyvitamin D3: A-ring structural motif that modulates interactions of vitamin D receptor with transcriptional coactivators

A concise synthesis of all four possible A-ring stereoisomers of 2,2-dimethyl-1,25-dihydroxyvitamin D3 and characterization of their distinct transcriptional features, which appear to have been inherited from the corresponding 2alpha-methyl derivatives, is reported.

A novel support system for patient immobilization and transportation for daily computed tomographic localization of target prior to radiation therapy

PURPOSE

To develop a method for quick and smooth transportation of patients from a computed tomography (CT) table to a linear accelerator (linac) table for confirming tumor center before radiation therapy.

MATERIALS AND METHODS

We developed a system using a subtable for patient immobilization that is transported via a customized stretcher. The patient lies on the subtable and is immobilized by a vacuum cushion and thermoplastic body cast. The subtable stretcher is used to carry the subtable from the CT table to the linac table. During transportation, the subtable is kept flat and shock to the subtable is carefully avoided. Between August 2001 and September 2002, a total of 9 patients with solitary upper lung tumors (superior to carina) were treated using this system.

RESULTS

Intrafractional tumor motion along the x (left-right), y (anterior-posterior), and z axis (superior-inferior) ranged from -2 mm to 2 mm, -2 mm to 2 mm, and -5 mm to 3 mm, respectively. The standard deviation of intrafractional tumor motion along the x, y, and z axis ranged from 0.5 mm to 1.5 mm, 0 mm to 1.7 mm, and 0.6 mm to 3.5 mm, respectively. Interfractional setup errors along the x, y, and z axis ranged from -5 mm to 4 mm, -6 mm to 8 mm, and -6 mm to 6 mm, respectively, and we could reduce interfractional setup errors in the majority of treatment sessions.

CONCLUSIONS

We developed a system that allows patients to be immobilized and transported to verify tumor location on a daily basis. This system is highly useful for reducing setup errors.

Remarkable effect of 2α-modification on the VDR antagonistic activity of 1α-hydroxyvitamin D3-26,23-lactones

Novel 2[small alpha]-methyl-, 2[small alpha]-(3-hydroxypropyl)- and 2[small alpha]-(3-hydroxypropoxy)-substituted 25-dehydro-1[small alpha]-hydroxyvitamin D-26,23-lactone derivatives were efficiently synthesized Reformatsky type allylation and palladium-catalyzed alkenylative cyclization processes, and their biological activities were evaluated. Introducing functional groups into the 2[small alpha]-position of the vitamin D-26,23-lactones resulted in remarkable enhancement of their antagonistic activity on vitamin D receptor (VDR).

Design and efficient synthesis of new stable 1alpha,25-dihydroxy-19-norvitamin D3 analogues containing amide bond

The design and synthesis of new 1alpha,25-dihydroxy-19-norvitamin D(3) analogues 3a-c, which have an amide bond in the molecule instead of the diene, are described. The A-ring moiety was constructed by a (3S,5S)-3,5-dihydroxypiperidine derivative (9, 11, or 13) prepared from D-mannose, and a CD-ring carboxylic acid 16 was synthesized from Grundmann's ketone. Coupling those parts gave desired 3a-c in good yield. This strategy can be applied in combinatorial chemistry; therefore, those compounds would be applicable as useful tools in the development of new drugs.

Synthesis and testing of 2alpha-modified 1alpha,25-dihydroxyvitamin D(3) analogues with a double side chain: marked cell differentiation activity

The 2alpha-methyl-, 2alpha-(3-hydroxypropyl)-, and 2alpha-(3-hydroxypropoxy)-derivatives of the 'double side chain' analogue of 1alpha,25-dihydroxyvitamin D(3) were synthesized using Trost A-ring/CD-ring connective strategy. Regarding the requisite A-ring building blocks, a new, high yield and stereoselective route to the 2alpha-methyl compound starting from D-glucose was developed. All three new analogues showed potent HL-60 cancer cell differentiation activity.

Metabolism of 2-methyl analogs of 1alpha,25-dihydroxyvitamin D3 in rat osteosarcoma cells (UMR 106)

Several novel A-ring modified analogs of 1alpha,25-dihydroxyvitamin D3 [1alpha,25(OH)2D3] have been synthesized in order to investigate the structure-function relationships of 1alpha,25(OH)2D3. We synthesized A-ring modified analogs which contain a methyl group on C-2 of the A-ring. There are eight 2-methyl diastereomers, which differ in the stereochemistry of the methyl group on C-2 and the hydroxyl groups on C-1 and C-3. Further our biological activity studies of the 2-methyl diastereomers indicated that the potency of each analog is highly dependent on the stereochemistry of the A-ring substituents [Konno et al., Biorg. Med. Chem. Letts. 8(2), 151-156 (1998); Nakagawa et al., Biochem. Pharmacol. 60(12), 1937-1947 (2000)]. For example, the VDR binding affinities exhibited by the 1alpha-isomers are significantly higher than those exhibited by the 1beta-isomers. Furthermore, out of all the 1alpha-isomers, the 2alpha-methyl isomers, when compared to the corresponding 2beta-methyl isomers, showed much higher potency in inducing cell differentiation of HL-60 cells, but failed to stimulate apoptosis. In contrast the 2beta-methyl isomers strongly stimulated apoptosis. At present it is unknown how the addition of the 2-methyl modification to the hormone, 1alpha,25(OH)2D3 alters its metabolism in target tissues. Previously, we reported that 1alpha,25(OH)2D3 is metabolized in rat osteosarcoma (UMR 106) cells via both the C-24 oxidation and the C-3 epimerization pathways. Therefore, we studied the metabolism of the four 1alpha,2-methyl diastereomers in UMR 106 cells. Our results indicated that in UMR 106 cells, all four diastereomers were metabolized into several polar metabolites via the C-24 oxidation pathway. Thus, the presence of the 2-methyl group on the A-ring did not inhibit the metabolism of the analogs via the C-24 oxidation pathway. However, it is significant to note that the 2-methyl group prevented the metabolism of the analogs via the C-3 epimerization pathway. In summary, we report that the 2-methyl group interferes with the action of the enzyme(s) involved in C-3 epimerization, but not with the enzyme 1alpha,25(OH)2D3-24-hydroxylase, which is responsible for C-24 oxidation pathway.

Determination of absolute configuration of 1,3-diols by the modified Mosher's method using their di-MTPA esters

1,3-Diols are frequently involved in biologically important compounds and, therefore, determination of the stereochemistry of these structural elements, in particular those in acyclic systems, has been one of the focuses of attention in natural products chemistry. The modified Mosher's method, commonly used for the determination of the absolute configuration of secondary alcohols, was applied to determine the absolute configuration of 1,3-diols with their di-MTPA esters. Several epimeric pairs of syn- and anti-1,3-diols with known absolute configurations were converted to the corresponding di-MTPA esters and the iDelta;delta values were then calculated. For the acyclic syn-1,3-diols, the iDelta;delta values were systematically arranged as predicted from the basic concept of the modified Mosher's method, demonstrating that the method is valid for these compounds. In contrast, the iDelta;delta values were irregularly arranged for the acyclic anti-1,3-diols and, accordingly, this method is not valid for these cases. These results are complementary to those of the previously reported CD exciton chirality method and, hence, the combined use of the modified Mosher's method and the CD exciton chirality method can determine the absolute configuration of the acyclic 1,3-diols. Also, this method is successfully applicable to cyclic 1,3-diols irrespective of their relative stereochemistry.

Efficient and versatile synthesis of novel 2alpha-substituted 1alpha,25-dihydroxyvitamin D(3) analogues and their docking to vitamin D receptors

Novel 2alpha-substituted 1alpha,25-dihydroxyvitamin D(3) analogues with 2alpha-alkyl and 2alpha-hydroxyalkyl groups were systematically synthesized from D-xylose. Their conformation on binding to the ligand binding domain (LBD) of the vitamin D receptor was analyzed. It has been found that the 2alpha-hydroxypropyl group best fits the cavity of the LBD, and the binding activity is three times higher than that for the natural hormone.

Synthesis and biological evaluation of all A-ring stereoisomers of 5,6-trans-2-methyl-1,25-dihydroxyvitamin D(3) and their 20-epimers: possible binding modes of potent A-ring analogues to vitamin D receptor

BACKGROUND

The secosteroid 1 alpha,25-dihydroxyvitamin D(3) (1) has a wide variety of biological activities, which makes it a promising therapeutic agent for the treatment of cancer, psoriasis and osteoporosis. Insight into the structure-activity relationships of the A-ring of 1 is still needed to assist the development of more potent and selective analogues as candidate chemotherapeutic agents, as well as to define the molecular mode of action.

RESULTS

All possible A-ring stereoisomers of 5,6-trans-2-methyl-1,25-dihydroxyvitamin D(3) (6a-h) and their 20-epimers (7a-h) were designed and efficiently synthesized. The dependence of the affinities for vitamin D receptor (VDR) and vitamin D binding protein (DBP), as well as the HL-60 cell differentiation-inducing activity, upon the stereochemistry of the A-ring and at C20 in the side chain was evaluated.

CONCLUSIONS

The binding affinities and potency of the 5,6-trans and 5,6-cis analogues were enhanced by a 2-methyl substituent in a certain orientation. Molecular docking studies based upon the X-ray crystal structure of VDR suggested that the axial 2-methyl group would be accommodated in a pocket surrounded by hydrophobic amino acid residues in the ligand binding domain, resulting in enhanced interaction.

Tissue specific metabolism of 1alpha,25-dihydroxy-20-epi-vitamin D3 into new metabolites with significant biological activity: studies in rat osteosarcoma cells (UMR 106 and ROS 17/2.8)

In a recent study, we investigated the metabolism of 1alpha,25-dihydroxy-20-epi-vitamin D3 (1alpha,25(OH)2-20-epi-D3), a potent synthetic vitamin D3 analog in the isolated perfused rat kidney and proposed that the enhanced biological activity of 1alpha,25(OH)2-20-epi-D3 is in part due to its metabolism into stable bioactive intermediary metabolites derived via the C-24 oxidation pathway (Siu-Caldera et al. [1999] J. Steroid. Biochem. Mol. Biol. 71:111-121). It is now well established that 1alpha,25(OH)2D3 and its analogs are metabolized in target tissues not only via the C-24 oxidation pathway but also via the C-3 epimerization pathway. As the perfused rat kidney does not express the C-3 epimerization pathway, we could not identify other possible bioactive metabolites of 1alpha,25(OH)2-20-epi-D3 such as 1alpha,25(OH)2-20-epi-3-epi-D3, derived via the C-3 epimerization pathway. Therefore, we studied the metabolism of 1alpha,25(OH)2-20-epi-D3 in rat osteosarcoma cells (UMR 106) which express both the C-24 oxidation and the C-3 epimerization pathways. Our results indicate that 1alpha,25(OH)2-20-epi-D3 is metabolized in UMR 106 cells into several metabolites which included not only the previously known metabolites of the C-24 oxidation pathway but also three new metabolites which were labeled as metabolites X, Y1, and Y2. Metabolite X was unequivocally identified as 1alpha,25(OH)2-20-epi-3-epi-D3. Even though definite structure identification of the metabolites, Y1 and Y2 was not achieved in our present study, we determined that the metabolite Y1 is produced from 1alpha,25(OH)2-20-epi-D3 and the metabolite Y2 is produced from 1alpha,25(OH)2-20-epi-3-epi-D3. We also noted the production of both 1alpha,25(OH)2-20-epi-3-epi-D3 and the two metabolites Y1 and Y2 in different rat osteosarcoma cells (ROS 17/2.8) which express only the C-3 epimerization pathway but not the C-24 oxidation pathway. Furthermore, we investigated the metabolism of 1alpha,25(OH)2-20-epi-D3 in the isolated perfused rat kidney in an earlier study. The results of this study indicated that the rat kidney unlike rat osteosarcoma cells did not produce either 1alpha,25(OH)2-20-epi-3-epi-D3 or the metabolites Y1 and Y2. Thus, it appears that the metabolites Y1 and Y2, like 1alpha,25(OH)2-20-epi-3-epi-D3, are produced only in specific tissues. Preliminary biological activity of each new metabolite is assessed by measuring its ability to generate VDR-mediated gene transcription. 1alpha,25(OH)2-20-epi-3-epi-D3 was found to be almost equipotent to 1alpha,25(OH)2-20-epi-D3 while the metabolites, Y1 and Y2 were found to be less active. The metabolite Y1 when compared to the metabolite Y2 has higher biological activity and its potency is almost equal to 1alpha,25(OH)2D3. In summary, we report for the first time tissue specific metabolism of 1alpha,25(OH)2-20-epi-D3 into several bioactive metabolites which are derived not only via the previously established C-24 oxidation and C-3 epimerization pathways but also via a new pathway. (c) 2001 Wiley-Liss, Inc.

[A case of endobronchial tuberculosis associated with bronchial asthma treated with high doses of inhaled corticosteroid]

A 46-year-old woman had been treated with 1,600-2,000 micrograms/day of beclomethasone dipropionate (BDP) and oral theophylline on the basis of a diagnosis of bronchial asthma in 1993. Eosinophilic pneumonia was diagnosed in June 1999, and she was then treated with 40 mg/day of oral prednisolone (PSL), which was gradually tapered off, and then stopped in October 1999. She was referred to our hospital because acid-fast bacilli were found in the sputum on January 18, 2000. Her chest radiographs and CT scans showed partial atelectasis of the right upper lobe, and fiberoptic bronchoscopy revealed bronchial inflammatory changes and whitish mucosal nodular lesions in the walls of the lower trachea, the right main bronchus and the orifice of the right upper lobe bronchus. She was found to have endobronchial tuberculosis. Anti-tuberculosis treatment with isoniazid, rifampicin, streptomycin and pyrazinamide was started. Serum levels of interferon-gamma were markedly elevated on admission. Asthma symptoms improved for a period of one month after the beginning of anti-tuberculosis treatment, despite the termination of inhaled corticosteroid. However, as the tuberculosis improved, the frequency and severity of the asthma increased and so corticosteroid inhalation was started again. Four months after administration of the anti-tuberculosis drug, fiberoptic bronchoscopy revealed that the endobronchial lesions had improved without any stenosis or constrictive changes. It was speculated that high doses of inhaled corticosteroid may have the potential to cause endobronchial tuberculosis whilst, ironically, at the same time preventing bronchial stenosis by endobronchial tuberculosis. This is an interesting case in which the asthma symptoms first decreased during the acute phase of endobronchial tuberculosis and then increased again after the tuberculosis improved.

Churg-Strauss syndrome after reduction of inhaled corticosteroid in a patient treated with pranlukast for asthma

Recently, various forms of Churg-Strauss syndrome (CSS) have been reported in association with the use of leukotriene receptor antagonists. A 53-year-old woman with a 5-year history of asthma associated with chronic sinusitis presented mononeuropathy, hypereosinophilia, and positive P-ANCA in October 1999. She had been treated with pranlukast (450 mg/day) and beclomethasone dipropionate (BDP) at a dose of 1,200 microg/day which had gradually been tapered to 800 microg/day over the previous 17 months. She was found to have CSS, and 60 mg/day of prednisolone was administered instead of pranlukast, resulting in an improvement of her symptoms and eosinophilia. Later, we confirmed that serum P-ANCA had been positive before the pranlukast treatment, but CSS vasculitis had not appeared at that time. We speculated that an underlying incomplete form of CSS was being masked in this case and that the reduction of inhaled corticosteroid might have been responsible for the unmasking of CSS.

Hepatocellular carcinoma depicted as hypoattenuation on CT hepatic arteriography (CTA) and hyperattenuation on CT during arterial portography (CTAP)

We report a 68-year-old man with three nodules of hepatocellular carcinoma (HCC) in a cirrhotic liver; the largest nodule was 3.0cm in diameter. The nodules showed hypoattenuation on computed tomography (CT) hepatic arteriography (CTA) and hyperattenuation on CT during arterial portography (CTAP), indicating that the dominant vascularity of the HCC nodules may have been the portal vein. A biopsy specimen obtained from the nodules showed well differentiated HCC (Edmondson-Steiner grade I). The imaging findings of the nodules on both CTA and CTAP are unusual, in spite of the rather large size, so this seemed suggestive of the hemodynamic properties of relatively large nodules of well differentiated HCC.

Systematic studies on synthesis, structural elucidation, and biological evaluation of A-ring diastereomers of 2-methyl-1alpha,25-dihydroxyvitamin D(3) and 20-epi-2-methyl-1alpha,25-dihydroxyvitamin D(3)

All possible A-ring diastereomers of 2-methyl-1alpha,25-dihydroxyvitamin D(3) (2) and 20-epi-2-methyl-1alpha,25-dihydroxyvitamin D(3) (3) were synthesized by palladium-catalyzed coupling reaction of A-ring 'enyne' synthons with CD-ring portions. The A-ring synthons were rationally synthesized via a novel and practical route, starting with methyl (R)-(+)- and (S)-(-)-3-hydroxy-2-methyl-propionate, in good yields. X-ray crystallographic analysis of 2alpha-methyl-1alpha,25-dihydroxyvitamin D(3) (2b) and conformational analysis of the A-ring of 2alpha-methyl-(2b) and 2beta-methyl-1alpha,25-dihydroxyvitamin D(3) (2f) were carried out, and the results are described. All A-ring diastereomers (2 and 3), thus synthesized, were biologically evaluated both in vitro and in vivo. The biologic potency was highly dependent on the stereochemistry of the A-ring substituents. In particular, 2b showed 4-fold higher vitamin D receptor [VDR] binding activity than the natural hormone, and its 20-epimer (3b) exhibited exceptionally high activity, 12-fold more potent in VDR binding, 7-fold in calcium mobilization, and 590-fold in induction of human promyelocytic leukemia (HL-60) cell differentiation as compared with the natural hormone. Further, the 20-epi-2beta-Me-1beta, 3alpha(OH)(2) isomer (3g) had significant biologic potencies compared to the natural hormone despite having 1beta-OH configuration. The transcriptional activities on human osteocalcin gene promoter, including VDRE in transfected mammalian cells, were also evaluated. Finally, there was a clear contrast between the effects of the 2-methyl group on the HL-60 cell differentiation- and apoptosis-inducing activities of 2 and 3.

Diagnostic significance of surfactant proteins A and D in sera from patients with radiation pneumonitis

Radiation pneumonitis (RP) is the most common complication of radiotherapy for thoracic tumours. The aim of this study was to evaluate the significance of pulmonary surfactant proteins (SP)-A and SP-D as new serum markers for RP. Twenty-five patients with lung tumour, who had received radiotherapy, were studied. At the completion of radiotherapy, the presence of RP was judged by chest plain radiography and chest high resolution computed tomography (HRCT). RP findings detected on chest plain radiography were seen in only three of 12 patients in whom RP was detected by HRCT. Nevertheless, both SP-A and SP-D concentrations in sera from the patients with RP were significantly higher than those from the 13 patients without RP (p = 0.0065, p = 0.0011, respectively). As with SP-A, ratios of SP-D at the completion, compared to at the initiation (1 week post/pre ratio), were also significantly higher in patients with RP than in patients without RP. When a post/pre ratio > 1.6 was considered positive, the SP-A and SP-D assays showed an 83% and 85% specificity, respectively. In conclusion, serum assays of surfactant proteins A and D may be of diagnostic value for detection of radiation pneumonitis, even when the radiographic change is faint.

Highly potent cell differentiation-inducing analogues of 1alpha,25-dihydroxyvitamin D3: synthesis and biological activity of 2-methyl-1,25-dihydroxyvitamin D3 with side-chain modifications

Eight 2-methyl substituted analogues of 20-epi-22R-methyl-1alpha,25-dihydroxyvitamin D3 (5) and 20-epi-24,26,27-trihomo-22-oxa-1alpha,25-dihydroxyvitamin D3 (6: KH-1060) were convergently synthesized. Preparation of the CD-ring portions with modified side chains of 5 and 6, followed by palladium-catalyzed cross-coupling with the A-ring enyne synthons (20a-d), (3S,4S,5R)-, (3S,4R,5R)-, (3S,4S,5S)- and (3R,4R,5S)-3,5-bis[(tert-butyldimethylsilyl)oxy]-4-methyloct-1-en-7-yne, afforded two sets of four A-ring stereoisomers of 20-epi-2,22-dimethyl-1,25-dihydroxyvitamin D3 (7a-d) and 20-epi-24,26,27-trihomo-2-methyl-22-oxa-1,25-dihydroxyvitamin D3 (8a-d). The biological profiles of the hybrid analogues were assessed in terms of affinity for vitamin D receptor (VDR) and HL-60 cell differentiation-inducing activity in comparison with the natural hormone. The combined modifications of the A-ring at the 2-position and the side chain yielded analogues with high potency.

Structure-specific control of differentiation and apoptosis of human promyelocytic leukemia (HL-60) cells by A-ring diastereomers of 2-methyl-1alpha,25-dihydroxyvitamin D(3) and its 20-epimer

1alpha,25-dihydroxyvitamin D(3) (1alpha,25(OH)(2)D(3)) has been shown to modulate not only proliferation and differentiation but also apoptosis of malignant cells, indicating that it would be useful for the treatment of hyperproliferative diseases such as cancer and psoriasis. Little information is available concerning structural motifs of the 1alpha,25(OH)(2)D(3) molecule responsible for modulation of differentiation and apoptosis. We synthesized all possible A-ring diastereomers of the 2-methyl-1alpha,25(OH)(2)D(3) and its 20-epimer and evaluated their biological activities in human promyelocytic leukemia (HL-60) cells. Surprisingly, the potent analogues could be clearly divided into two groups: (i) those bearing the 1alpha- and 3beta-hydroxyl groups on the A-ring were potent inducers of differentiation and growth inhibitors of HL-60 cells and (ii) those bearing the 1beta-hydroxyl group together with either 3alpha- or 3beta-hydroxyl groups on the A-ring were potent stimulators of apoptosis in these cells. We have clearly identified for the first time the structural motifs on the basis of the stereochemistry of both hydroxyl groups at positions 1 and 3 of the A-ring of the 1alpha,25(OH)(2)D(3) molecule responsible for the induction of differentiation and apoptosis of HL-60 cells. These findings provide useful information not only for structure-function studies of 1alpha,25(OH)(2)D(3) analogues but also for the development of therapeutic agents for the treatment of leukemia and other cancers.

Synthesis, biological evaluation, and conformational analysis of A-ring diastereomers of 2-methyl-1,25-dihydroxyvitamin D(3) and their 20-epimers: unique activity profiles depending on the stereochemistry of the A-ring and at C-20

All eight possible A-ring diastereomers of 2-methyl-1, 25-dihydroxyvitamin D(3) (2) and 2-methyl-20-epi-1, 25-dihydroxyvitamin D(3) (3) were convergently synthesized. The A-ring enyne synthons 19 were synthesized starting with methyl (S)-(+)- or (R)-(-)-3-hydroxy-2-methylpropionate (8). This was converted to the alcohol 14 as a 1:1 epimeric mixture in several steps. After having been separated by column chromatography, each isomer led to the requisite A-ring enyne synthons 19 again as 1:1 mixtures at C-1. Coupling of the resulting A-ring enynes 20a-h with the CD-ring portions 5a,b in the presence of a Pd catalyst afforded the 2-methyl analogues 2a-h and 3a-h in good yield. In this way, all possible A-ring diastereomers were synthesized. The synthesized analogues were biologically evaluated both in vitro and in vivo. The potency was highly dependent on the stereochemistry of each isomer. In particular, the alpha alpha beta-isomer 2g exhibited 4-fold higher potency than 1 alpha,25-dihydroxyvitamin D(3) (1) both in bovine thymus VDR binding and in elevation of rat serum calcium concentration and was twice as potent as the parent compound in HL-60 cell differentiation. Furthermore, its 20-epimer, that is, 20-epi-alpha alpha beta 3g, exhibited exceptionally high activities: 12-fold higher in VDR binding affinity, 7-fold higher in calcium mobilization, and 590-fold higher in HL-60 cell differentiation, as compared to 1 alpha,25-dihydroxyvitamin D(3) (1). Accordingly, the double modification of 2-methyl substitution and 20-epimerization resulted in unique activity profiles. Conformational analysis of the A-ring by (1)H NMR and an X-ray crystallographic analysis of the alpha alpha beta-isomer 2g are also described.