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Biomedical subjects

M D'Incalci

Publications and source records attributed to M D'Incalci.

At least 127 records · Page 7Linked to original sources
PubMed1995

Changes in doxorubicin distribution and toxicity in mice pretreated with the cyclosporin analogue SDZ PSC 833.

SDZ PSC 833 (PSC 833) is a cyclosporin A analogue that is under clinical investigation in combination with doxorubicin (Dx) or other anticancer agents as a type-1 multidrug resistance (MDR-1)-reversing agent. The present study was focused on the effects of PSC 833 on the distribution and toxicity of Dx in non-tumor-bearing CDF1 male mice. Mice were given PSC 833 i.p. at 30 min before i.v. Dx treatment. Dx levels were determined by a high-performance liquid chromatography (HPLC) assay at different times during a 72-h period following Dx treatment in the serum, heart, intestine, liver, kidney, and adrenals of mice. In all tissues, Dx area under the concentration-time curve (AUC) values were much greater in mice receiving 10 mg/kg Dx in combination with 12.5 or 25 mg/kg PSC 833 than in mice receiving Dx alone. The highest increase in Dx concentrations was found in the intestine, liver, kidney, and adrenals. Lower, albeit significant, differences were found in the heart. PSC 833 did not appear to influence either urinary or fecal Dx elimination or Dx metabolism to a great extent. Doses of PSC 833 devoid of any toxicity potentiated the acute and delayed toxicity of Dx dramatically. The mechanism responsible for this enhanced toxicity has not yet been elucidated but is likely to be related to an increased tissue retention of Dx due to inhibition of the P-glycoprotein (Pgp) pump by PSC 833, as has recently been proposed for cyclosporin A.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1995

Clinical pharmacokinetics of altretamine.

Altretamine (hexamethylmelamine) is an antitumour drug with demonstrated antitumour activity in refractory ovarian cancer. Due to its poor water solubility, the drug has been given by the oral route. In all animal species, including humans, altretamine undergoes oxidative N-demethylation with the formation of hydroxymethyl derivatives as intermediates. Hydroxymethylmelamines are believed to be responsible for the cytotoxic and antitumour activity of the drug. The inter-hand intrapatient variability of the bioavailability of altretamine after oral administration represents an important drawback for effective clinical use of this drug. The variability appears to be mostly related to the first-pass effect and therefore may be overcome by intravenous administration of the drug. Although attempts to administer the drug intravenously have not been successful in the past, some investigations on the use of the new parental formulation of altretamine are in progress.

Administration, Oral↗
PubMed1995

Differential expression of c-fos proto-oncogene in two subclones derived from a human ovarian cancer cell line.

The expression of the c-fos proto-oncogene was studied in two sublines of the human ovarian cancer cell line SW626. One subline (SW/B) presents the typical 2.0 kb mRNA which is detectable within 15 min. after serum stimulation of quiescent cells, is inducible by protein synthesis inhibitors and has a half-life of approximately 10-15 min. The other subline (SW/A) does not show the 2.0 kb mRNA, but instead presents a mRNA of higher molecular weight capable of hybridizing with the c-fos probe. This bigger mRNA is neither serum inducible nor sensitive to protein synthesis inhibitors. The presence of this transcript is not due to any gross alteration in the gene structure. Differences were found in the DNA binding proteins obtained from nuclei of the two sublines. A protein able to bind the promoter of c-fos was found in SW/B but not in SW/A. In the latter subline no amplification products were observed using two different sets of primers covering the 3' coding region of the human gene. Conversely, the expected fragments were amplified from mRNA obtained from the SW/B subline.

Base Sequence↗
PubMed1995

Sequence-specific DNA interactions by novel alkylating anthracycline derivatives.

New alkylating anthracycline derivatives with promising antitumor activity have been synthesized. We selected two of these compounds, 4-demethoxy-N,N-bis(2 chloroethyl)-4'-methylsulfonyl-daunorubicin (FCE 27726) and 4-demethoxy-3'-deamino-3'aziridinyl-4'-methylsulfonyl daunorubicin (FCE 28729), comparing their interaction with DNA and that of the non-alkylating derivative 4-demethoxy-4'-methylsulfonyl-daunorubicin (FCE 27894). The two alkylating derivatives were more cytotoxic than idarubicin and presented low cross-resistance with doxorubicin. Both FCE 27726 and FCE 28729 were found to alkylate guanines at the N7 position in the major groove with roughly the same specificity, but at different concentrations. FCE 27726 was 10 times more potent than FCE 28729 in alkylating DNA. At higher concentrations, FCE 27726 was able to alkylate adenines, possibly at the N3 position contained in a sequence 5'-PyAA. FCE 27726, as expected, was able to form DNA interstrand cross-links either in vitro and in vivo in treated cells. FCE 28729 did not form DNA interstrand cross-links in vivo. In vitro, at high concentrations, some DNA interstrand cross-links were evident. The non-alkylating derivative FCE 27894 did not produce any alkylation or DNA interstrand cross-links either in vitro or in vivo.

Animals↗
PubMed1995

Clinical pharmacology of chronic oral etoposide in patients with small cell and non-small cell lung cancer.

We aimed to evaluate the pharmacokinetics and pharmacodynamics of etoposide given chronically by the p.o. route to patients with small cell and non-small cell lung cancer. Single daily p.o. doses of 100 mg etoposide were given for 21 consecutive days every 4 weeks to 39 previously untreated patients with small cell lung cancer and 10 patients with non-small cell lung cancer. Bioavailability was studied after one i.v. and one p.o. dose of 100 mg etoposide given 48 h before and on day 1 of treatment, respectively. Etoposide plasma levels were measured using the HPLC method. Inter- and intrapatient variability of the area under the curve of the concentration versus time (AUC) during the first cycle were evaluated using a limited sampling model; the variability of etoposide plasma concentrations (Ecs) during the first cycle was assessed by weekly blood samples taken 24 h after dosing. The overall bioavailability of etoposide (mean +/- SD) was 67% +/- 22% and was not affected by fasting. A much higher inter- than intrapatient variability of both the AUC and 24-h Ec determined on days 8, 15, and 22 was found. Neutropenia was dose limiting and of varying degrees (mean +/- SD of absolute neutrophil count nadir at the first cycle: 1.5 +/- 1.2 x 10(3)/microliter). Neutropenia WHO grade >/=3 occurred in 38% of the patients after the first cycle. Pharmacodynamic analyses showed a significant relationship between the mean 24-h Ec and neutropenia, expressed as log- of absolute neutrophil count nadir or as a relative decrease of neutrophils. A correlation between a critical value of mean 24-h Ec (0.34 microgram/ml) and a high probability of achieving a greater than 80% decrease in absolute neutrophil count was found. Two pharmacodynamic models (one previously described and one developed in this study) were used to evaluate the possibility of predicting neutropenia on the basis of individual etoposide pharmacokinetics and baseline absolute neutrophil count. Pharmacokinetic studies have shown a high interpatient variability and a relatively low intrapatient variability of AUC and 24-h Ec. The application of the pharmacodynamic models and mean 24-h Ec cutoff values has proven statistically valid to predict the occurrence of severe neutropenia. However, it remains to be demonstrated in a prospective manner whether the application of pharmacokinetic/ pharmacodynamic knowledge can improve the overall therapeutic outcome of chronic p.o. treatment with etoposide.

Administration, Oral↗
PubMed1994

Determination of L-asparagine in biological samples in the presence of L-asparaginase.

The antileukaemic efficacy of L-asparaginase is related to the ability of the enzyme to induce the complete disappearance from plasma of L-asparagine, an amino acid essential to lymphoblastic leukaemia cells. It is not feasible to monitor L-asparagine plasma levels in patients under L-asparaginase treatment using the usual analytical procedures as the enzyme continues the hydrolysis of L-asparagine after blood sampling and during plasma extraction. A method was therefore developed for the determination of L-asparagine in patients receiving L-asparaginase. Sulphosalicylic acid is added to blood samples to deproteinize and inactivate L-asparaginase rapidly. The samples are then analysed by HPLC using a Novapack C18 column and fluorescence detection. With the same method L-asparagine is determined in blood cells and, by difference, plasma levels are calculated. This method is highly specific and sufficiently simple and sensitive for clinical use.

Asparaginase↗
PubMed1994

Introduction of wild-type p53 in a human ovarian cancer cell line not expressing endogenous p53.

Utilizing a temperature sensitive p53 mutant (pLTRp53cGval135) which expresses mutant p53 at 37 degrees C and a wild-type like p53 at 32 degrees C, we transfected a human ovarian cancer cell line (SKOV3) which does not express endogenous p53. Among the different clones obtained, we selected three clones. Two were obtained from simultaneous transfection of p53 and neomycin resistance expression plasmids (SK23a and SK9), the other was obtained from transfection experiments utilizing the neomycin resistance gene only (SKN). Introduction of mutant p53 did not alter the morphology or growth characteristics of this ovarian cancer cell line. Upon shifting to the permissive temperature, a dramatic change in morphology and growth rate was observed in SK23a and SK9 cells that is associated with the presence of a wild-type like p53. SKN and SKOV3 cells maintained at 32 degrees C did not change morphology and only slightly reduced proliferation. Both SK23a and SK9 cells did not show evidence of apoptosis when measured up to 72 hours of maintenance at 32 degrees C. In contrast to what observed in other cell lines, SK23a and SK9 cells maintained at 32 degrees C were not blocked in G1, but they were accumulated in G2-M. This accumulation was transient and could be due either to a blockade or to a delay in the G2 progression. No down-regulation of c-myc was observed in p53 expressing clones when shifted to the permissive temperature. In these conditions gadd45 mRNA expression was highly stimulated in SK9 and SK23a cells but not in SKN cells. In both clones Gas1 mRNA was not detected either at 37 degrees C or 32 degrees C. This system represents a new and useful model for studying the effect of the absence of p53 (SKOV3 or SKN), presence of mutated p53 (SK23a and SK9 kept at 37 degrees C) or wild type p53 (SK23a and SK9 kept at 32 degrees C) on the mechanism of response of cancer cells to DNA damaging agents.

Animals↗
PubMed1994

High-performance liquid chromatographic assay for the determination of the novel podophyllotoxin derivative dimethylaminoetoposide (NK611) in human plasma.

A simple, rapid and reproducible plasma assay for the determination of the novel epipodophyllotoxin derivative, dimethylaminoetoposide (NK611, I) and its N-demethyl metabolite (II) is reported. The method involves solid-phase extraction using an isolute C18 cartridge and HPLC separation on a reduced-activity C18 column (8 cm long) with a mobile phase of acetonitrile-water-0.1 M phosphoric acid (23:76:1, v/v/v); peaks are detected at 205 nm. The intra- and inter-day precision and accuracy are within 5 and 4% for I and II, respectively. The sensitivity is 20 ng/ml for both I and II. The assay is applicable to clinical pharmacokinetic studies. In one cancer patient who received both an oral and an intravenous dose of 10 mg of I the bioavailability was 82% and the clearance 20.8 ml/min.

Antineoplastic Agents↗
PubMed1994

Comparison of paclitaxel and docetaxel activity on human ovarian carcinoma xenografts.

The antitumour activity of paclitaxel (NSC 125973) and docetaxel (RP 56976, NSC 628503) was evaluated and compared against human ovarian carcinoma (HOC) xenografts in nude mice. Paclitaxel and docetaxel were given intravenously (i.v.) at a dose range of 16.6-34.5 mg/kg, once every 4 days for three consecutive doses to nude mice with HOC xenografts, transplanted subcutaneously (s.c.) (HOC18 and HOC22-S) or intraperitoneally (i.p.) (HOC8 and HOC22). Paclitaxel and docetaxel, at the highest dosage, induced complete tumour regression in 80-100% and 67% of mice bearing HOC22-S and HOC18 s.c., respectively. Both drugs cured 100% of mice bearing early stage HOC22 tumour in the peritoneal cavity, while treatment at an advanced stage significantly increased the survival time of all the mice. Both induced a 57% cure rate in mice bearing HOC8 in the peritoneal cavity. Paclitaxel and docetaxel were more effective than cisplatin (4 mg/kg, same dosing regime as above) used as a reference compound. These findings indicate that paclitaxel and docetaxel were highly active on four HOC xenograft models. No significant difference between them was detected in ovarian cancer xenografts.

Animals↗
PubMed1994

Mechanism of cytotoxicity of 5,10-dideazatetrahydrofolic acid in human ovarian carcinoma cells in vitro and modulation of the drug activity by folic or folinic acid.

Inhibition of clonogenic potential by the glycinamideribonucleosyl transformylase inhibitor 5,10-dideazatetrahydrofolic acid (DDATHF, Lometrexol) was evaluated in vitro in a human ovarian carcinoma cell line, SW626. Drug-induced inhibition of clonogenic potential is a function of the dose and time of exposure and is independent of the formation of DNA single-strand breaks or de novo synthesis of protein. Simultaneous treatment with 100 microM hypoxanthine completely prevented the inhibition of clonogenic potential caused by 0.5 microM DDATHF. DDATHF blocked cells in the early-middle S-phases of the cell cycle, and there was a corresponding marked reduction in the rate of DNA synthesis after drug withdrawal. The cytotoxic potential of DDATHF was modulated by the folic acid concentration present in the medium. In a medium containing 0.22 microM folic acid, DDATHF cytotoxicity was at least 100 times that in a regular medium containing 2.22 microM folic acid, levels which, however, are about 100 times those found in human plasma. DDATHF cytotoxicity differed moderately when folic acid concentrations varied between 0.22 and 0 microM, suggesting that folic acid does not necessarily antagonise DDATHF anti-tumour activity. Folinic acid at a concentration as low as 0.1 microM can completely rescue cells when given simultaneously with 0.5 microM DDATHF. When folinic acid was given 24 h after DDATHF, a reversal of cytotoxicity was observed at 0.5 and 1 microM, but to a much lesser extent than simultaneous treatment. When folinic acid was added after 48 or 72 h of DDATHF washout, even at a high concentration and for a long time, no reduction in DDATHF cytotoxicity was found. In conclusion, the study highlights the modulation of DDATHF cytotoxicity by folic acid or by folinic acid and provides further rationale for in vivo clinical investigation with these combinations.

Antineoplastic Agents↗
PubMed1994

L1210 cells selected for resistance to methoxymorpholinyl doxorubicin appear specifically resistant to this class of morpholinyl derivatives.

We investigated the mechanism of resistance in murine L1210 leukaemia cells selected after treatment with FCE 23762 methoxymorpholinyl doxorubicin: (MMRDX), a methoxymorpholinyl derivative of doxorubicin active in vitro and in vivo on multidrug-resistant (mdr) cells, currently undergoing phase I clinical trials. The resistant subline obtained after repeated in vitro treatments, L1210/MMRDX, is resistant in vitro and in vivo to all tested methoxymorpholinyl derivatives and to cyanomorpholinyl doxorubicin, but shows resistance to morpholinyl derivatives only in vivo or following their activation with rat S9-liver fractions in vitro. L1210/MMRDX cells are sensitive to classic mdr- and altered topoisomerase (AT)-mdr-associated drugs. These cells do not appear to overexpress the mdr1 gene, nor do they exhibit impaired intracellular drug accumulation and efflux or altered levels of glutathione and glutathione S-transferase. The extent of DNA single-strand break formation and, after microsomal activation, of DNA interstrand cross-links after treatment with MMRDX was similar in the parent and the resistant subline. The mechanism of resistance in L1210/MMRDX cells remains to be identified but may prove a novel one, highly specific for this class of mdr-active anthracyclines.

Animals↗
PubMed1994

3T3 NIH murine fibroblasts and B78 murine melanoma cells expressing the Escherichia coli N3-methyladenine-DNA glycosylase I do not become resistant to alkylating agents.

The role of alkylation of the N3 position of adenine in the cytotoxicity of alkylating agents in mammalian cells is still undefined. By co-transfecting NIH3T3 murine fibroblast and murine B78 H1 melanoma cells with pSG5tag and pSV2neo, we obtained clones expressing the mRNA of the bacterial tag gene coding for N3-methyladenine-DNA glycosylase I (Gly I), which specifically repairs N3-methyladenine. The levels of Gly I were 400 times higher in NIH3T3 pSG5tag (clone 3.9.4) and 12-33 times higher in B78 H1 tag clones (2A4, 2A6, 2C3 and 2D1) than in the respective control cells. The sensitivity to alkylating agents was evaluated in tag-expressing cells in comparison with pSG5, pSV2neo co-transfected control cells. As regards the cytotoxic activity of methylating agents (N-methylnitrosourea, N-methyl-N'-nitro-N-nitrosoguanidine, dimethylsulfate and temozolomide) and other alkylators with different structure and different interactions with DNA such as CC-1065 and FCE-24517 (minor groove binders known to bind to N3 of adenine), 4-[bis(2-chloroethyl)amino]-L-phenylalanine and cis-diamminedichloroplatinum II, cytotoxicity was the same for tag-expressing and non-expressing cells. These results suggest that the increased expression of N3-methyladenine-DNA glycosylase is not necessarily a crucial mechanism for the resistance of cells to alkylating agents.

3T3 Cells↗