Selective vitamin D receptor modulators and their effects on colorectal tumor growth.

The active form of vitamin D, 1,25-dihydroxyvitamin D(3) [1,25(OH)(2)D(3)], is an endocrine hormone whose classic role is the maintenance of calcium homeostasis. It is well documented that 1,25(OH)(2)D(3) also has anti-tumor effects on a number of cancers and cancer cell lines including breast, colorectal, gastric, liver, ovarian, prostate, and non-melanoma skin cancers. Included in the anti-tumor activities of 1,25(OH)(2)D(3) are its ability to cause antiproliferation, prodifferentation and decrease angiogenesis. Furthermore, through regulation of the plaminogen activator (PA) system and a class of proteolytic enzymes called matrix metalloproteinases (MMPs), 1,25(OH)(2)D(3) reduces the invasive spread of tumor cells. Because of the calcemic limitations of using 1,25(OH)(2)D(3) as a therapy, we have tested the effects of a novel Gemini vitamin D analogue, Deuterated Gemini (DG), on mouse colorectal cancer. We demonstrated that DG is more potent in reducing tumor volume and mass, compared to control and 1,25(OH)(2)D(3). DG significantly prevented (100% reduction, p<0.05) the invasive spread of colorectal tumor cells into the surrounding muscle, and had no effect on serum calcium levels. Thus, DG acts as a selective vitamin D receptor modulator (SVDRM) by enhancing select anti-tumor characteristic 1,25(OH)(2)D(3) activities, without inducing hypercalcemia. Thus, DG shows promise in the development of colorectal cancer therapies.

Vitamin D and cancer.

The correlation between decreased morbidity and mortality of cancer and exposure to sunlight is known. The many biological functions of vitamin D that contribute to cancer prevention have only recently begun to be appreciated. Once activated 1,25-dihydroxyvitamin D [1,25(OH)2D3] functions as a potent inhibitor of normal and cancer cellular proliferation. Vitamin D deficiency in mice led to a 60% increase in colon tumor growth, compared to vitamin D-sufficient mice. The ligand binding domain of the Vitamin D receptor was shown to accommodate a class of 1,25(OH)2D3-analogs that possess an additional side-arm. These novel Gemini analogs were evaluated in vitro and in vivo. Select Gemini analogs were 100 times or more effective in inhibiting colon tumor growth in mice, compared to their parent compound. Correcting vitamin D deficiency may decrease the risk of developing colon cancer, while the novel Gemini 1,25(OH)2D3-analogs have the potential for therapeutic application in human colon cancer.

Colon cancer and solar ultraviolet B radiation and prevention and treatment of colon cancer in mice with vitamin D and its Gemini analogs.

It has been recognized that people who live at higher latitudes and who are vitamin D deficient are at higher risk of dying from many common cancers including colon cancer. To evaluate the role of vitamin D deficiency on colon tumor growth, Balb/c adult male mice were fed either a vitamin D sufficient or vitamin D deficient diet for 10 weeks. Mice were arranged into groups of six and each animal received subcutaneously 10(4) MC-26 cells in the posterior trunk. The tumor size was recorded daily. By day 9 there was a significant difference in tumor volume between the vitamin D sufficient and vitamin D deficient mice. By day 18 the vitamin D deficient animals had a tumor size that was 56% larger compared to the animals that were vitamin D sufficient. To determine whether treatment with active vitamin D analogs could further decrease colon tumor growth in a vitamin D sufficient state, groups of mice were treated with the novel 19-nor-Gemini compounds. The mice were fed a low calcium diet. Twenty-four hours after tumor implantation, the mice received, three times weekly, one of the vitamin D analogs or the vehicle. The group that received Gemini 1,25-dihydroxy-21(3-hydroxy-3-trifluoromethyl-4-trifluoro-butynyl)-19-nor-20S-cholecalciferol (3) showed a dose-dependent decrease in tumor volume. On day 19, at the dose level of 0.02microg molar equivalents (E), the tumor volume was reduced by 41% when compared to the control group. At the same time point, the hexadeuterated analog 1,25-dihydroxy-21(3-hydroxy-3-trifluoromethyl-4-trifluoro-butynyl)-26,27-hexadeutero-19-nor-20S-cholecalciferol (4), administered at the 10-fold lower dose of 0.002microgE, showed a 52% reduction in tumor volume (p<0.05), compared to the control group. Animals that received 1,25(OH)(2)D(3) at 0.002 and 0.02microg showed a trend in tumor volume reduction at the highest dose but the changes were not statistically significant. An evaluation of serum calcium concentrations revealed that the calcium levels were normal in all groups, except the group receiving 0.02microgE of 4. The results from these studies demonstrate that vitamin D deficiency may accelerate colon cancer growth and that novel Gemini analogs of 1,25(OH)(2)D(3) may be an effective new approach for colon cancer treatment.

Antimetabolites produced by microorganisms XVI. Synthesis of N5-hydroxy-2-methylarginine and N5-hydroxy-2-methylornithine.

N5-Hydroxy-2-methylornithine and N5-hydroxy-2-methylarginine were synthesized. 2-Amino-5-hydroxy-2-methylpentanoic acid was prepared from 5-hydroxy-2-pentanone and converted to N-(tetrahydro-3-methyl-2-oxo-2H-pyran-3-yl) acetamide which was treated with hydrogen bromide affording 2-(acetylamino)-5-bromo-2-methylpentanoic acid. This acid was esterified with methanol and used to alkylate anti-benzaldoxime yielding methyl 2-(acetylamino)-2-methyl-5-[(phenylmethylene)amino]-pentanoate N5-oxide which, upon hydrolysis, yielded N5-hydroxy-2-methylornithine, and, upon aminolysis and short acid-treatment, gave N2-acetyl-N5-hydroxy-2-methylornithinamide. Carbamimidoylation and hydrolysis of the latter compound furnished N5-hydroxy-2-methylarginine.

Antimetabolites produced by microorganisms. XV Synthesis of 2-methyl-L-arginine, 2-methyl-L-ornithine and their enantiomers.

5-(3-Azidopropyl)-5-methyl-2, 4-imidazolidinedione was prepared either from 5-(3-chloropropyl)-5-methyl-2,4-imidazolidinedione or 5-methyl-5-(3-[(4-methylphenyl)sulfonyloxy]-propyl)-5-methyl-2, 4-imidazolidinedione and hydrogenolyzed to the corresponding amine which, after carbamimidoylation, afforded 2-methyl-DL-arginine upon acid hydrolysis. Racemic 2-methylarginine was converted enzymically to a mixture of 2-methyl-D-arginine and 2-methyl-L-ornithine. 2-Methyl-L-arginine was reconstructed from 2-methyl-L-ornithine via its Cu(II) chelate with O-methyl-isourea and 2-methyl-D-ornithine was obtained by alkaline hydrolysis of 2-methyl-D-arginine.

Antibiotic X-5108. IX. Chemical conversion of mocimycin to aurodox and derivatives of aurodox, goldinamine and mocimycin.

Mocimycin was converted to the acylesters by selective acylation of the hydroxyl group of the 4-hydroxy-1-methyl-2(1H)pyridinone moiety. Subsequent N-methylation at the nuclear nitrogen and removal of the protective group from the resulting reaction products afforded aurodox. Mono-O-acetylmocimycin and several analogous aurodox esters thus prepared possess antibacterial activity in vitro and growth-promotion properties in poultry. Esters of aurodox involving the hydroxyl group of the 4-hydroxy-1-methyl-2(1H)pyridinone moiety are activated. Accordingly, acetic acid treatment of the aurodox esters generates O-acylgoldinamines which undergo transacylation furnishing N-acylgoldinamines. Alternatively, N-acylgoldinamines can be prepared by selective mono--o-arylsulfonylation of aurodox, liberating o-arylsulfonylgoldinamine by treatment with acetic acid followed by N-acylation and removal of the protective arylsulfonyl group. A third approach to N-acylgoldinamines consists in direct N-acylation of goldinamine itself which is prepared by acetic acid treatment of aurodox. None of these derivatives prepared, however, exhibited significant antimicrobial or growth-promoting properties, suggesting that goldinonic acid moiety, or a closely related derivative thereof, is required for biological activity.

Antimetabolites produced by microorganisms. XV synthesis of 2-methyl-arginine, 2-methyl-l-ornithine and their enantiomers.

A new arginine antimetabolite was isolated from the fermentation broth of a new strain of Streptomyces and identified as 2-methyl-L-arginine.

Microbial products. IV. X-14847, a new aminoglycoside from Micromonospora echinospora.

Micromonospora echinospora strain X-14847 produces gentamicin A as the major antibiotic together with a new aminoglycoside, termed X-14847, and identified as a 2-amino-2-deoxy-alpha-D-glucopyranosyl myo-inositol. This report describes the taxonomy of the culture, fermentation conditions, the isolation and the identification of X-14847.

Microbial products. VIII. Azinothricin, a novel hexadepsipeptide antibiotic.

Azinothricin was isolated from the culture filtrate of Streptomyces sp. X-14950 in crystalline form. It represents a new type of hexadepsipeptide antibiotic as it contains a 19-membered cyclodepsipeptide ring composed of six unusual amino acids and bearing a novel C21 side chain. Azinothricin was identified as [(3S,4S,7R(S*),10S,17R,20S,23R)[2S(2'R*,5'S*, 6'S*)3S*]]-alpha-ethyl-6-(3-ethyl-1, 5-dimethyl-4-oxo-1,5-heptadienyl)- N-(1,8, 14,15,18,21,27-heptaaza-21-hydroxy-7-(1-hydroxyethyl)-2,6,9,16,19, 22-hexaoxo-4-isopropyl-20-(methoxy-methyl)-17,18-dimethyl-5-oxa tricyclo [21.4.0.0(10,15)]heptacosan-3-yl)tetrahydro-alpha, 2-dihydroxy-5-methyl-2H-pyran-2-acetamide and is primarily active against Gram-positive microorganisms.

Microbial products. VI Five novel metabolites related to benz[a]anthracene from an unidentified actinomycete designated X-14881.

Five metabolites of actinomycete X-14881 were isolated from the fermentation broth and characterized. The major component was identified as [3R-(3 alpha,6a beta,7 beta,12 alpha,12a alpha)] or [3S-(3 beta,6a alpha, 7 alpha,12 beta,12a beta)]-6a, 7,12-trihydroxy-3,4,6a, 7,12, 12a-hexahydro-8-methoxy-3-methylbenz[a]-anthracen-1(2H)-one; the other four are closely related derivatives thereof.

[Intraoperative blood sampling for parathyroid hormone measurement during total parathyroidectomy and autotransplantation in patients with renal hyperparathyroidism]. / Stellenwert der intraoperativen Blutabnahme zur Parathormonbestimmung während totaler Parathyreoidektomie mit Autotransplantation bei Patienten mit renalem Hyperparathyreoidismus.

Normalisation of intact parathyroid hormone serum level confirms sufficient resection of parathyroid tissue after total parathyroidectomy in patients with secondary hyperparathyroidism. The short half-life of the intact parathyroid hormone is such that complete resection may even be confirmed by intraoperative monitoring of the hormone, and operative exploration thus reduced. We tested intact parathyroid hormone serum levels in 9 patients during total parathyroidectomy, preoperatively, after the removal of each gland, after autotransplantation and 1 month postoperatively. The serum levels of the intact parathyroid hormone were significantly reduced after removal of each gland. The total percentage decrement after parathyroidectomy with autotransplantation was 77%. However intact parathyroid hormone levels had normalised in all patients one month after the operation. The absence of perioperative normalisation of intact parathyroid hormone serum levels in our patients cannot be defined as a predictor of incomplete resection in total parathyroidectomy. The definition of an intraoperative cut-off-level concerning the decrement of intact parathyroid hormone levels remains to be proven in further studies.