3 alpha-Hydroxysteroid-5 beta-oxidoreductase in tissue cultures of Digitalis lanata

Putative intermediates of cardenolide biosynthesis, namely progesterone, pregnenolone, 5 beta-pregnane-3,20-dione or 5 beta-pregnan-3 beta-ol-20-one, were administered to light- or dark-grown shoot cultures of Digitalis lanata. The unsaturated compounds were reduced to their respective 5 alpha-pregnanes, 5 beta-pregnane-3,20-dione was reduced to 5 beta-pregnan-3 alpha-ol-20-one and 5 beta-pregnan-3 beta-ol-20-one was isomerized to the respective 3 alpha-pregnane. Suspension cultures of Digitalis lanata, on the other hand, accumulated both the 3 alpha- and the 3 beta-isomer of 5 beta-pregnan-3-ol-20-one when incubated in the presence of 5 beta-pregnane-3,20-dione. When 5 beta-pregnan-3 alpha-ol-20-one was administered the cultured cells accumulated large amounts of the 3 beta-isomer together with small amounts of 5 beta-pregnane-3,20-dione, which may be regarded as an intermediate during the isomerization reaction. Cell-free, buffered extracts from light-grown shoots were shown to reduce 5 beta-pregnane-3,20-dione almost exclusively to 5 beta-pregnan-3 alpha-ol-20-one when 0.05 M MgCl2 were present in the incubation mixture. Under these conditions the formation of 5 beta-pregnan-3 beta-ol-20-one was inhibited. The enzyme activity could be recovered from membrane-free supernatants. Optimum enzyme activity occurred at pH 7.0 and 42 degrees C. The energy of activation was 56.2 kJ/mol and the enzyme reaction was found to be NADPH-dependent. SH reagents were essential for enzyme activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Separation of cardiac glycosides by micellar electrokinetic capillary electrophoresis

The separation of mixtures of primary and secondary cardiac glycosides by micellar electrokinetic capillary electrophoresis modified by cyclodextrins, urea and sodium cholate proved to be suitable for the determination of these hydrophobic compounds. It was possible to distinguish the two anomeric cardenolides glucodigifucoside and glucodigiglucomethyloside with all three buffer systems. Electropherograms of crude plant cell extracts from Digitalis lanata were obtained with this method.

Therapy of refractory/relapsed acute myeloid leukemia and blast crisis of chronic myeloid leukemia with the combination of cytosine arabinoside, tetrahydrouridine, and carboplatin

Eight patients, of whom four had acute myeloid leukemia (AML) and four had chronic myeloid leukemia (CML) blast crisis, were treated with a combination of cytosine arabinoside (ARA-C: 1,600 mg/m2 in three patients, 1,200 mg/m2 in five patients), tetrahydrouridine (THU: 2,800 mg/m2 in two patients, 2,646 mg/m2 in one patient, 2,100 mg/m2 in five patients), and carboplatin (900 mg/m2 in four patients, 720 mg/m2 in one patient, 450 mg/m2 in three patients). As a result of this treatment, five of the eight patients became aplastic. Two of the four patients with CML blast crisis reverted to the chronic phase and two of the four patients with acute nonlymphocytic leukemia (ANLL) attained a remission (one partial remission and one complete remission). The major toxicities included myelosuppression, unacceptable hepatotoxicity, and diarrhea. Pharmacokinetics studies revealed that the addition of carboplatin did not significantly change the disposition of ARA-C. ARA-C levels were not significantly changed in comparison with those obtained in a prior study of ARA-C with THU (ARA-C plasma levels at 3 h, 2630 +/- 1170 ng/ml).

Mutational status of codons 12 and 13 of the N- and K-ras genes in tissue and cell lines derived from primary and metastatic prostate carcinomas

N- and K-ras mutations at codons 12 and 13 were investigated using oligonucleotide hybridization analysis after PCR amplification and subsequent sequence analysis of the amplified DNA from the region of interest in the following prostatic primary and metastatic (met) carcinoma-derived cell lines: 1013L (primary), PC3 (bone met), DU145 (brain met), and LNCaP (lymph node met). We also examined fresh and archival primary and metastatic prostate tumor tissue and benign prostatic hypertrophy specimens. All prostatic cells and tissues examined contain at least one wild-type N- and K-ras allele with respect to codons 12 and 13. No mutations were found at N-ras codon 13. The only mutation seen in the prostatic cell lines and tissues was a K-ras codon 12 position II G-to-T transversion. Since these are established nonclonal cell lines that have adapted to tissue culture, it is possible that this mutation does not represent the mutational state of prostatic carcinoma in vivo. However, the lack of consistent mutation in the ras genes amplified directly from tumors suggests that when ras mutations occur during the progression of prostatic carcinoma, they are late-stage events not directly involved in the initial development of disease. Immunoprecipitation studies using pan-ras antibodies revealed no evidence of altered expression of Ras proteins.

Phase II trial and pharmacokinetic assessment of intravenous melphalan in patients with advanced prostate cancer

Alkylating agents have been reported to yield response rates of up to 20% in hormone-refractory prostate cancer. Melphalan was studied in four small trials in which the drug was given orally. In this phase II trial, melphalan (30 mg/m2) was given intravenously every 28 days to 27 patients with hormone-refractory prostate cancer. Pharmacokinetic sampling was performed so as to describe the clearance of melphalan in this population and in an attempt to carry out pharmacodynamic modeling for toxicity and response. Prostate-specific antigen (PSA) was also assessed prospectively. No objective responses to this regimen were documented. The median survival for patients on this trial was 11.5 months. There was no correlation between drug clearance and measured creatinine clearance and no relationship between systemic exposure and toxicity. A decrease of > 50% in serum PSA that was sustained for > 6 weeks was documented in two patients, most notably in one patient who has survived for more than 29 months. Intravenous melphalan is not an active agent in hormone-refractory prostate cancer.

12β-Hydroxylation of digitoxin by suspension-cultured Digitalis lanata cells: Production of digoxin in 20-litre and 300-litre air-lift bioreactors

A biotransformation process for the production of digoxin was developed using Digitalis lanata cell suspension cultures. Digitoxin was used as the substrate for biotransformation. Digoxin production was carried out in a variety of vessels, including 1-l exsiccators, 20-l glass reactors and a 300-l air-lift bioreactor. A culture volume of 200 l was established after 28 d and the cells were then cultured semi-continuously in a 300-l bioreactor employing the draw-fill cultivation method. Maximal digoxin production was achieved in an 8% glucose medium with a production optimum after 40-60 h of incubation in the presence of 0.65-0.8 mmol digitoxin per l. Levels of 0.52, 0.53 and 0.60 mmol digoxin per l suspension were achieved in 1-l, 20-l and 300-l vessels, respectively. About 80% of the digoxin produced was found in the bathing medium.

Production of Forskolin by Axenic Coleus forskohlii Roots Cultivated in Shake Flasks and 20-l Glass Jar Bioreactors*

Root cultures of COLEUS FORSKOHLII Briq. were initiated from primary callus or IBA-treated suspension cultures and maintained on Gamborg's B5 medium containing 1 mg/l IBA. Transformed root cultures were established by infecting surface-sterilized leaves with AGROBACTERIUM RHIZOGENES strain 15834. Transformation was confirmed by mannopine detection. These cultures displayed the typical characteristics of hairy root cultures, with the sole exceptions of slow growth in hormone-free medium and accelerated growth on medium containing phytohormones. All root cultures examined formed forskolin and its derivatives in amounts ranging from 500 to 1300 mg/kg dry weight, corresponding to about 4 to 5 mg/l. During cultivation roots could be cut into small pieces without affecting growth and forskolin production. Scale-ups of the cultivation procedure were performed in 20-l glass jars with a working volume of 10 to 13l. Forskolin production in bioreactors was better than in shake flasks. Levels of almost 14 mg/l could be reached after 21 d of cultivation. As in the shake flask experiments cutting the roots did not affect growth or productivity in a negative way.

A non-invasive method for the routine-estimation of fresh weight of cells grown in batch suspension cultures

A simple apparatus was designed to allow sedimentation of plant cells grown in batch suspensions in Erlenmeyer flasks. After sedimentation the height of the cell mass along the glass wall was measured with a ruler fixed in the apparatus. The cell volume after sedimentation, calculated from this height, appeared highly correlated with the fresh weight of cells. This result was found with eight cell lines in two Laboratories. The method proved to be very suitable to allow routinely measurement of FW without the destruction of cells, from many samples, in a short time, during each phase of the growth cycle.

Phenotypic analysis of 1-B-D-arabinofuranosylcytosine deamination in patients treated with high doses and correlation with response

Two phenotypes for 1-B-D-arabinofuranosylcytosine (ara-C) deamination corresponding to a ratio of distribution for "slow" (ratio, less than or equal to 14) vs "fast" (ratio, greater than 14) deaminators of 70%:30%, have been determined on the basis of studies on plasma ratios of 1-B-D-arabinofuranosyluracil/ara-C (ara-U/ara-C) in 56 subjects treated with high-dose ara-C (3 g/m2 infused i.v. over 3 h). A positive correlation of age with the concentration of ara-U was observed. In a subgroup of 36 patients with leukemia, the ara-U/ara-C pattern was similar to that observed for all 56 subjects. In these leukemic patients, who were treated with combinations of ara-C plus other conventional agents, a tendency toward a positive response (complete response + partial response) was found for those showing low ara-U/ara-C ratios (slow deaminators). The phenotypic effect of deamination in acute leukemia needs to be evaluated prospectively.

Pharmacokinetics of ara-C and ara-U in plasma and CSF after high-dose administration of cytosine arabinoside

Cytosine arabinoside (ara-C) and uracil arabinoside (ara-U) levels were measured in the plasma, cerebrospinal fluid (CSF), and urine of 10 patients exhibiting primary central nervous system lymphoma who received 31 infusions of high-dose ara-C (3 g/m2) as part of their treatment regimen. Peak plasma and CSF ara-C levels were 10.8 and 1.5 micrograms/ml, respectively. Ara-C was cleared more rapidly from plasma than from CSF. Ara-U appeared rapidly in both plasma and CSF, reaching a peak that was 10 times higher than the corresponding ara-C concentration (104 and 11.2 micrograms/ml, respectively). Only 4%-6% of the dose was excreted unchanged in the urine, but 63%-73% of it appeared as ara-U within the first 24 h. The presence of leptomeningeal lymphoma did not affect the CSF level of ara-C or ara-U.

Therapy of refractory/relapsed acute leukemia with cytosine arabinoside plus tetrahydrouridine (an inhibitor of cytidine deaminase)--a pilot study

Thirty two patients with refractory or recurrent acute leukemia or blast crisis of chronic myelocytic leukemia were treated with 1-beta-D-arabinofuranosylcytosine (Ara-C), 100 mg/m2 [group I (n = 15)] or 200 mg/m2 [group II (n = 18)], and tetrahydrouridine (THU) 350 mg/m2, given concurrently as a 3 h continuous intravenous infusion at 12 h interval for eight doses. Two of 13 (15.3%) evaluable patients in group I achieved a complete response, both of whom had acute myelocytic leukemia. In group II, seven of 14 evaluable patients (50%) obtained objective responses--six with complete responses (42.8%) and one with partial response (7%). Myelosuppression was seen in all patients with a median duration of 32.5 days (group I) and 36.3 days (group II), respectively. Non-hematologic toxicity consisted of nausea, vomiting, diarrhea, conjunctivitis, skin rash, hepatocellular toxicity, hemorrhage, and renal toxicity. Pharmacokinetic studies revealed, for group I, mean peak plasma Ara-C levels at 3 h (Cp3h) of 1254 ng/ml, area under the curve (AUC) 4651 ng x h/ml, total body clearance (TBC) 32.65 l/h/m2, renal clearance (RC) 7.04 l/h/m2 with a mean of 12.36% of the injected amount of Ara-C excreted unchanged in urine over the first 24 h. The corresponding mean values for group II are Cp3h 3305 ng/ml, AUC 15080 ng x h/ml, TBC 20.48 l/h/m2, RC 7.02 l/h/m2 and 26.23%. Ara-C 200 mg/m2 combined with THU gave serum Ara-C levels and response rates comparable to those achieved with high dose Ara-C (HiDAC) (greater than or equal to 1 g/m2). Central nervous system toxicity associated with HiDAC was not seen. Pharmacokinetics for uracil arabinoside (Ara-U) in patients treated with Ara-C 200 mg/m2 plus THU, were comparable to values seen with Ara-C for Cp3h, AUC and 24 h urine, amounting to 3160 ng/ml, 21717 ng x h/ml and 23.62% whereas TBC was significantly lower (p less than 0.001) for Ara-U than for Ara-C (3.02 versus 20.48 l/h/m2).

Inhibition of HIV replication by Hyssop officinalis extracts

Crude extracts of dried leaves of Hyssop officinalis showed strong anti-HIV activity as measured by inhibition of syncytia formation, HIV reverse transcriptase (RT), and p17 and p24 antigen expression, but were non-toxic to the uninfected Molt-3 cells. Ether extracts from direct extraction (Procedure I), after removal of tannins (Procedure II), or from the residue after dialysis of the crude extract (Procedure III), showed good antiviral activity. Methanol extracts, subsequent to ether, chloroform and chloroform ethanol extractions, derived from procedure I or II, but not III, also showed very strong anti-HIV activity. In addition, the residual material after methanol extractions still showed strong activity. Caffeic acid was identified in the ether extract of procedure I by HPLC and UV spectroscopy. Commercial caffeic acid showed good antiviral activity in the RT assay and high to moderate activity in the syncytia assay and the p17 and p24 antigen expression. Tannic acid and gallic acid, common to other teas, could not be identified in our extracts. When commercial products of these two acids were tested in our assay systems, they showed high to moderate activity against HIV-1. Hyssop officinalis extracts contain caffeic acid, unidentified tannins, and possibly a third class of unidentified higher molecular weight compounds that exhibit strong anti-HIV activity, and may be useful in the treatment of patients with AIDS.

Transdermal versus subcutaneous leuprolide: a comparison of acute pharmacodynamic effect

Transdermal administration of peptides has been limited by the barrier properties of the skin. We compared the acute luteinizing hormone (LH) response to subcutaneous and transdermal administration of an LH-releasing hormone agonist (leuprolide). Eighteen volunteers received 5 mg leuprolide added to electrically powered patches delivering a current of 0.22 microA (transdermally). One week later, they received a 5 mg subcutaneous dose. LH response was measured. The area under the curve for LH response, maximum LH response, and time to maximum LH response were similar. Time to first response was shorter (147 +/- 108 minutes [transdermally] and 73 +/- 74 minutes [subcutaneously]; p less than 0.05), and the area under the curve for the first 150 minutes was greater (3655 +/- 2246 mIU.min/ml [transdermally] and 8666 +/- 4067 mIU.min/ml [subcutaneously]; p less than 0.05) for subcutaneous delivery. No major adverse effects were seen. This electrically powered transdermal technique merits further study.

Two-stage cultivation of Digitalis lanata cells: semicontinuous production of deacetyllanatoside C in 20-litre airlift bioreactors

A two-stage cultivation method was employed to develop a semicontinuous biotransformation process for the production of deacetyllanatoside C, a cardenolide of the important digoxin series. Digitoxin was used as the substrate for biotransformation. The process was optimized in 1-l shake flasks and then established on the 20-l scale using two airlift bioreactors, one for cell growth (working volume 12 litres) and another for deacetyllanatoside C production (working volume 18 litres). Growth and production phases were synchronized and the process finally ran semicontinuously in 7-d cycles. Six consecutive production runs were performed yielding a total of 43.8 g deacetyllanatoside C.

Clinical pharmacokinetics of intravenously injected tritiated vinzolidine

Vinzolidine (VZL), a novel, semi-synthetic vinca alkaloid showing evidence of oncolytic activity in phase I/II clinical trials, was studied in six patients for its pharmacokinetic and metabolic behavior. Following i.v. administration of [3H]-VZL at doses of 5, 6.7, and 9 mg/m2, blood and urine samples were collected and analyzed by sample oxidation and HPLC. Following a single i.v. dose, decay of total tritium in plasma was tetraphasic, with a rapid initial t1/2 alpha of 0.044 +/- 0.013 h, followed by a t1/2 beta of 0.54 +/- 0.22 h and a t1/2 gamma of 9.48 +/- 4.89 h; the terminal t1/2 gamma was 219 +/- 57 h. The mean plasma clearance of total tritium was 0.054 +/- 0.044 l.kg/h, and the mean volume of distribution was 14.3 +/- 5.4 l/kg; mean urinary excretion was 13.6% +/- 4.3% of the delivered radioactivity. Qualitative analysis of plasma and urine revealed the predominance of unchanged VZL plus two unidentified metabolites with different elution times. In comparison with oral VZL, as previously reported, i.v. injected VZL showed comparable values with respect to the volume of the central compartment (VC), plasma clearance (Clp), and terminal t1/2 for total tritium. Qualitatively, the metabolites observed in plasma and urine were comparable in number and quantity with values obtained in analyses after oral administration.

Phase I trial of intravenous vinzolidine (LY 104208) given on a biweekly dosing schedule

Vinzolidine (VZL) is a semisynthetic vinca alkaloid with broad antitumor activity in animal models of malignancy but had unpredictable toxic effects when given orally to humans. To minimize the toxic effects due to potential erratic gastrointestinal absorption, this drug was restudied in man as an intravenous preparation given as a rapid injection every two weeks. The maximum tolerated dose (MTD) on this schedule was 9.0 mg/m2 with unpredictable leukopenia (usually occurring 5-14 days post treatment but appearing erratically), constipation, paralytic ileus, and inappropriate ADH syndrome as major toxicities. Nonhematologic toxicities were dose-limiting. Repetitive dosing at two week intervals was associated with leukopenia at D 14-15 in some but not all patients treated above 5.0 mg/m2 precluding further treatment on schedule. In contrast, the oral MTD of this agent in our prior studies was 45 mg/m2 with no evidence of delayed leukopenia. Intrapatient variability of toxicity was small; interpatient variability of toxicity was substantial and did not correlate with prior therapy. Because of the presence of delayed hematologic toxicity on repetitive dosing schedules, intravenous VZL should be given on a dosing schedule longer than 14 days. No antitumor activity was seen in this study.

Predictive initial parameters for response of stage D prostate cancer to treatment with the luteinizing hormone-releasing hormone agonist goserelin

One hundred eighteen patients with stage D (D1 or D2) prostate cancer with a mean age of 69 years were treated with monthly goserelin (Zoladex; ICI 118, 630; ICI Americas Inc, Wilmington, DE, property of Imperial Chemical Industries PLC) injections and the data were analyzed for predictive parameters for best response and time to treatment failure (National Prostatic Cancer Project [NPCP] and Eastern Cooperative Oncology Group [ECOG] criteria). For best response in a univariate analysis, the performance status (PS 0-1 v 2-3) (P = .01), hematocrit (P = .04), and pain (P = .04) were significant. For time to treatment failure by univariate analysis, ECOG performance status (0-1 v 2-3) was most predictive (P less than .0001), followed by pain at entry (P = .0002), initial testosterone (T) level (greater than 250 ng/dL) (P = .0005), age less than 69 years (P = .02), alkaline phosphatase (less than 115 IU/L) (P = .03), hemoglobin (less than 14 g/dL) (P = .03), whereas normal acid phosphatase (less than 3 IU/mL) (P = .29) was not predictive. In multivariate analysis for time to treatment failure, only the ECOG performance status was of significance (P = .01). Estimated median time to treatment failure for PS of 0-1 was 88 weeks and for PS of 2-3 was 31 weeks.

Δ5-3β-hydroxysteroid dehydrogenase/Δ5-Δ4-ketosteroid isomerase (3β-HSD), a possible enzyme of cardiac glycoside biosynthesis, in cell cultures and plants of Digitalis lanata EHRH

The in vitro transformation of pregnenolone into progesterone in Digitalis lanata tissues was shown to be catalyzed by a 3β-hydroxysteroid dehydrogenase/ketosteroid isomerase (3β-HSD). Product formation was monitored by HPLC. The enzyme could be partially characterized and 3β-HSD activities were measured in various Digitalis lanata tissues and in cell cultures of other plant species. Since no correlation was observed between biosynthetic competence of the tissue and 3β-HSD activity, it was concluded that this enzyme does not play a major role in regulating cardenolide biosynthesis.

The production of secondary metabolites by plant cells cultivated in bioreactors1

Plant cell cultures are a potential source of pharmaceutically important plant metabolites. In the past few years a lot of success has been achieved in the field of the cultivation of plant cells on a large scale. Special bioreactor systems, such as airlift or drum-type fermentors have been devised for the mass cultivation of plant cells. Classical stirred-tank bioreactors (up to 75000 l volume) have also been used for the cultivation of plant cells and the production of important plant metabolites. Plant cells proliferate much slower than microbial cells. In consequence, the time taken to grow a plant cell suspension from the shake-flask level (300 ml) to the production scale (20,000 l) takes about 3 to 6 weeks. Nevertheless, the cost analyses available show that the production of valuable chemicals by a suitable plant cell culture process could be commercially viable. Plant cells have been grown in batch and repeated batch culture, and single- stage as well as two-stage processes have been developed for the production of secondary metabolites by fermentor-cultured plant cells. There are, however, only few cell culture processes that have attracted industrial attention as yet. Biological rather than technological problems are the main obstacles to a more common use of fermentor-cultured plant cells in industry.