Franca Formelli

Fluorescence assays and pharmacokinetic studies of 4′-deoxydoxorubicin and doxorubicin in organs of mice bearing solid tumors

SummaryThe pharmacokinetic of 4′-deoxydoxorubicin, a new analog of doxorubicin, was compared with that of its parent compound in mice treated with equal and equiactive doses. The levels of total fluorescence due to the initial drugs and to metabolites were determined in tissue extracts by fluorometry. 4′-Deoxydoxorubicin reached the same tissue levels as doxorubicin in all the organs tested except in spleen and lung, where a higher peak was found in the animals treated with the new analog. The rate of elimination of 4′-deoxydoxorubicin from the organs tested was higher than that of doxorubicin.

Fluorescence assay of tissue distribution of 4-demethoxydaunorubicin and 4-demethoxydoxorubicin in mice bearing solid tumors

SummaryThe tissue distribution of 4-demethoxydaunorubicin and 4-demethoxydoxorubicin was studied in comparison with that of their parent compounds, daunorubicin and doxorubicin, in mice bearing transplanted tumors. The doses administered were equal or equitoxic to those of their parent compounds. The levels of total fluorescence due to initial drugs and metabolites were determined on tissue extracts by fluorometry. After administration of equal doses of daunorubicin and 4-demethoxydaunorubicin, the calculated Cxt values of 4-demethoxydaunorubicin equivalents were higher than those for daunorubicin in all the organs tested except the heart. In animals treated with equitoxic doses, lower 4-demethoxydaunorubicin levels were found in all the organs tested. In mice treated with equitoxic doses of doxorubicin and 4-demethoxydoxorubicin, 4-demethoxydoxorubicin reached higher drug concentrations than doxorubicin in spleen and liver, whereas in all the other organs tested lower drug levels were found. The rate of drug disappearance from organs was slower in animals treated with 4-demethoxyderivatives than in those treated with their parent drugs.

Comparative pharmacokinetics and metabolism of doxorubicin and 4-demethoxy-4'-O-methyldoxorubicin in tumor-bearing mice

SummaryIt has been reported that 4-demethoxy-4′-O-methyldoxorubicin (4-dm-4′-O-methylDX) is more potent than doxorubicin (DX), equally active in some murine leukemias and solid tumors, and almost devoid of cardiotoxicity. We used HPLC to investigate the metabolism and the disposition of this drug in comparison with DX in mice bearing colon 38 adenocarcinoma SC and treated with IV doses of the two drugs that were equiactive and equitoxic (4-dm-4′-O-methylDX 1 mg/kg; DX 10 mg/kg). 4-Dm-4′-O-methylDX was metabolized to a polar metabolite, presumably 4-demethoxyDX, which was eliminated more slowly than the parent drug from all the organs and accounted for 25%–50% of total fluorescence; traces of two metabolites less polar than the parent drug (2% of total fluorescence) were found only at early times in the liver. In DX-treated mice traces of doxorubicinol (1%–3% of total fluorescence) were found in tumor and organs, and two aglycones were detected only at early times in the liver. In plasma both drugs declined biexponentially and 4-dm-4′-O-methylDX was eliminated slightly faster than DX. The rate of elimination of the new analogue from lung, kidney, spleen, and small intestine was faster than that of DX; in heart and liver 4-dm-4′-O-methylDX was detectable for only up to 24 h, while DX was detectable for up to 7 days. In the tumor the kinetics and the elimination patterns of the two drugs were similar. The distribution of 4-dm-4′-O-methylDX, as a percentage of the administered dose, was 1.3–2 times higher than that of DX in the organs and 3 times higher in the tumor, which suggests an improved selectivity of the new analogue for the tumor compared with DX.

Biologic characterization and chemotherapeutic response of MS-2 tumor: a non-regressing mouse sarcoma derived from MSV-M-induced sarcoma

Abstract MS- 2 tumor produced in BALB/c mice by transplant of in vitro cultivated cells derived from a primary MSV-M tumor in mice did not show spontaneous regression but grew progressively and killed the host. The MS- 2 tumor was histologically classified as a malignant sarcoma. In syngeneic BALB/c mice, the i.m. transplanted MS- 2 tumor had a mean doubling time of 2.5 days when the tumor mass was 500 mg and 14 days when the tumor reached 4.0 g . MS- 2 tumor cells showed a high ability to metastatize (tested by bioassay). The organ mainly involved was the lung. In a small percentage of mice, metastases were also detected in spleen, liver, kidney, brain and blood. The activity of: cyclophosphamide, daunorubicin, adriamycin and 4 ′-epi-adriamycin on the MS- 2 tumor was evaluated. The effects on both tumor growth and pulmonary metastases were detected. In parallel, the drugs were tested on the highly immunogenic T-MSV tumor, obtained by serial. in vivo passages of the primary MSV-induced tumor. Daunorubicin did not have any therapeutic effect on the growth of MS- 2 tumor; adriamycin produced a marked delay of the tumor growth and a significant increase of the life span; cyclophosphamide produced a longer delay in tumor growth than adriamycin did, but the life span was only slightly increased. On the T-MSV tumor, daunorubicin and adriamycin reduced tumor growth and did not affect spontaneous tumor regression; cyclophosphamide reduced tumor growth but completely abolished the spontaneous regression. Adriamycin and its new derivative 4 ′-epi-adriamycin, given to mice in which the MS- 2 tumor had been surgically removed, inhibited the presence of tumor cells at the lung level. The MS- 2 tumor studied in parallel with the T-MSV tumor allows the comparison of drug activity on a highly or weakly immunogenic tumor. Moreover, the MS- 2 tumor is a viable model for studying the activity of chemotherapeutic drugs on lung metastases and their adjuvant effect on surgery.

Correlation between inhibitory effect on prolactin secretion and antitumor activity of new ergoline compounds on DMBA-induced tumors in rats

Five recently synthesized (355/1057, 355/1000, 355/1101, 355/1138 and FCE 21336) and 4 well-known (bromocriptine, metergoline, 1-demethylmetergoline and pergolide) prolactin-lowering ergoline derivatives and 1 ergoline (nicergoline) without antiprolactin activity were tested against 7-12-dimethyl-benzanthracene (DMBA)-induced mammary carcinomas in rats. Nicergoline did not show any activity, while the other compounds, tested at doses inhibiting prolactin secretion, proved active against established tumors and on the onset of new tumors. The activity of 3 of the new ergolines (355/1000, 355/1057 and FCE 21336) and of bromocriptine and pergolide was also tested at different oral doses and was correlated with serum prolactin levels 24 hr after the last dose. All the compounds proved highly effective, inducing 50-60% regression of the initial tumors. The inhibition of serum prolactin levels was dose-related and, for all the compounds tested except bromocriptine, a good correlation was found between doses administered and complete tumor remissions.

Effect of medroxyprogesterone acetate and of some antiinflammatory agents on mouse erythroleukemia cell differentiation.

The effects of medroxyprogesterone acetate (MPA) on differentiation were examined using mouse erythroleukemia (MEL) cells and compared with those of antiinflammatory agents. MPA at low doses (10−6 - 10−7 M) induced 10–15 % cells to differentiate, whereas high doses (10−4 - 10−5 M) caused a 30 % inhibition of dimethylsulfoxide (DMSO)-induced differentiation. Dexamethasone (10−4 - 10−8 M), a steroid antiinflammatory agent, significantly inhibited (77–70 %) DMSO-induced differentiation, whereas indomethacin, aspirin, flurbiprofen and BW755c (non steroid antiinflammatory agents) at the same concentrations had no effect. If added 24 h before DMSO, the inhibitory effects of MPA and dexamethasone increased to 65 % and 95 %, respectively, whereas indomethacin (10−5 M) caused only a 30 % inhibition and the other drugs were inactive. None of these antiinflammatory agents affected differentiation when used without DMSO. MPA and dexamethasone inhibitory effects on DMSO-induced differentiation did not seem to be mediated through the inhibition of the synthesis of prostaglandins, since non-steroid prostaglandin inhibitors were slighly active only when added 24 h before DMSO.

Evaluation of a platinum-doxorubicin complex in experimental tumor systems

SummaryOn the basis of previous observations indicating that the platinum (II)-doxorubicin complex (coordinated via the amino sugar) was active against resistant ascitic leukemias, the preclinical evaluation of this complex was extended to a variety of experimental tumors, including solid doxorubicin-resistant tumors (P388/DX, B16 melanoma with acquired resistance, and MXT mammary carcinoma with natural resistance). In the treatment of sensitive tumors (Gross leukemia and Lewis lung tumor) the complex provided efficacy comparable to that of doxorubicin. Among resistant models, only P388/DX, which is only weakly responsive to cisplatin itself, showed significant sensitivity to the platinum complex. Since all resistant tumors were transplanted in the same site (s.c.) of the same mouse strain, it is likely that the different tumor response reflects different underlying mechanisms of cell resistance rather than alterations in pharmacologic behavior of the anthracycline after covalent binding to platinum. The data reported in this preclinical study support the potential value of this approach to overcome selected manifestations of resistance to anthracyclines. In contrast to the highly toxic doxorubicin/cisplatin combination, doxorubicin complexation with platinum was not associated to an increase in toxicity.

Tumors and dental and ocular abnormalities after treatment of infant rats with adriamycin.

In rats repeatedly treated subcutaneously as infants with adriamycin in 2 cycles of 4 treatments each, the induction of ocular and dental abnormalities and tumors was studied. Cataracts appeared from 18 to 26 days in 80 % of CD rats treated with 1.15 mg/kg/day of adriamycin and from 28 to 104 days in 55 % of Wistar-Lewis rats given 0.75 mg/kg/day adriamycin. Abnormal growth of incisors was observed in 30 % of the CD rats and in 44 % of the Wistar-Lewis rats. At lower doses, no such abnormalities were found. At about 1 year after treatment, 100 % of the CD rats treated with 0.75 mg/kg/day adriamycin and about 60 % of the Wistar-Lewis rats treated with 0.75 and 0.5 mg/kg/day adriamycin developed tumors, which were histologically classified.

Effect of Medroxyprogesterone Acetate and Doxorubicin on Sublines of 13762 Mammary Adenocarcinoma in Rats

Abstract The 13762 mammary adenocarcinoma was subjected to serial transplantation in rats, freezing and thawing and in vitro cultivation. Following these procedures, various sublines were identified which differed in histological pattern, oncogenicity and sensitivity to medroxyprogesterone acetate treatment. Medroxyprogesterone acetate, administered s.c. at the dose of 100 mg/kg/day, 5 days/week for 4 weeks, delayed tumor onset and growth of sublines that had maintained their sensitivity to 17-β-estradiol. Doxorubicin, administered i.v. at the dose of 3.6 mg/kg once a week for 4 weeks, was more active on the hormone-sensitive than on the hormone-insensitive subline. Simultaneous combined treatment for 4 weeks with these agents caused higher growth inhibition than either single agent given alone. Other schedules of treatment were less effective. The following conclusions can be drawn: (1) the 13762 mammary tumor is heterogeneous, and hormone-sensitive or insensitive cell populations can be selected by simple manipulations; (2) there is no correlation between histological pattern and hormone sensitivity; (3) medroxyprogesterone acetate is active on sublines sensitive to 17-/3-estradiol treatment, but it also improves the activity of doxorubicin on hormone insensitive sublines.