Search

A sensitive and rapid LC-MS/MS assay for the quantitative determination of 5-methylindirubine (5-MI) in murine plasma is described. A 50-microL-murine plasma aliquot was spiked with an internal standard, indirubine-3-monoxime (IMO), and extracted with 1.25 mL diethyl ether. Dried extracts were reconstituted in methanol-water (8:2, v/v) and 10 microL-volumes were injected onto the HPLC system. Separation was achieved on a Gemini C18 column (150 mm x 2.1 mm ID, particle size 5 microm) using an alkaline eluent (10 mM ammonium hydroxide-methanol (5:95, v/v)). Detection was performed by negative ion electrospray followed by tandem mass spectrometry. The assay quantifies 5-MI in a range from 1 to 500 ng/mL using 50 microL of murine EDTA plasma samples. Validation results demonstrate that 5-MI concentrations can be accurately and precisely quantified in murine plasma. This assay is used to support pre-clinical pharmacologic studies with 5-MI.

3-Amino-2,3,6-trideoxyhexopyranoses are essential constituents of most anthracycline antitumour antibiotics. For an investigation of structure-activity relationships, the four diastereomeric amino sugars daunosamine, acosamine, ristosamine, and epi-daunosamine were synthesised in short and efficient routes starting from commercially available rhamnose. Several glycosyl donors were provided and their use was exemplified in the synthesis of acosaminyl-epsilon-isorhodomycinone.

Background: Ecteinascidin-743 (ET743) is a novel antitumour agent originating from the Caribbean tunicate Ecteinascidia turbinata. It has potent cytotoxic and antitumour activity and a potential new mechanism of action. The aim of the present study was to further explore the antitumour activity of ET743 in human tumour xenografts from melanoma, non-small-cell lung and ovarian cancer., Design: As the antitumour profile of ET743 was largely unknown a chemo-sensitive and a marginal chemo-resistant human tumour xenograft were selected for each tumour type. ET743 was administered intravenously using two administration schedules (days 0, 4, 8 and 0-2, 13-15)., Results: ET743 was very active at the maximum tolerated dose (MTD) in the chemo-sensitive xenograft melanoma MEXF 989, non-small-cell lung cancer LXFL 529, and ovarian cancers HOC22 and (marginally resistant to cisplatin) HOC18. Activity was also seen at 1/2 MTD. Apart from HOC18, ET743 caused complete remissions in the responding xenografts. The compound was inactive in the chemo-resistant xenograft melanoma MEXF 514 and non-small-cell lung cancer LXFA 629. In terms of antitumour activity the days 0, 4, 8 schedule had advantages over the days 0-2, 13-15 schedule., Conclusions: ET743 is a very effective agent in chemo-sensitive and marginal chemo-resistant xenografts, but inactive in chemo-resistant tumour xenografts. The activity of ET743 in the marginally cisplatin-resistant ovarian cancer HOC18 might indicate absence or incomplete cross-resistance against cisplatin. It is recommended to include melanoma, non-small-cell lung cancer, and ovarian cancer in phase II clinical trials and to use an intermittent schedule.

Purpose: To determine the maximum tolerable dose (MTD), principal toxicity, and pharmacologic behaviour of Cemadotin-HCl, a novel antimitotic peptide., Patients and Methods: Cemadotin-HCl (10.0 to 27.5 mg/m2/day every three weeks) was administered as a 24-hour intravenous (i.v.) continuous infusion to patients with advanced cancer. Pharmacokinetic analyses were performed during the first treatment cycle. Blood samples were taken over 48 hours and analyzed by radioimmunoassay., Results: Hypertension was the dose-limiting toxicity (DLT). This type of toxicity was observed at all dose levels, but grade 3 (CTC) was observed only at dose levels 20.0, 25.0 and 27.5 mg/m2. This effect was reversible but in three patients associated with signs of cardiac ischemia. Other significant toxic effects were neutropenia, asthenia, tumor pain and transient liver enzyme elevation. A linear pharmacokinetics was observed. The best curve fit was obtained with a two-compartment model with a terminal half-life of approximately 10 hours at each dose level, a volume of distribution at steady state of approximately 9 l/m2 and a total clearance of approximately 0.6 l/hour/m2. Neither partial nor complete responses were observed although minor tumor regressions were seen in a patient with carcinoma of unknown primary (CUP) and in another patient with liver metastases from a colon cancer., Conclusions: Hypertension was the dose-limiting toxicity of Cemadotin-HCl administered as a continuous 24-hour infusion. The recommended dose for further evaluation of its anticancer efficacy in disease-oriented phase II studies with this schedule is 15.0 mg/m2. The nature of the principal cardiovascular toxicity remains unclear. The observed toxicities appeared to be significant but manageable.

Background: Vascular endothelial growth factor (VEGF) is a polypeptide with specific effects on endothelial cell growth and blood vessel permeability. Recent studies demonstrated a key role for VEGF in tumor neovascularization, which is a prerequisite for tumor proliferation and metastasis., Materials and Methods: We studied the expression of VEGF mRNA in a panel of 65 different human tumor xenografts of various histologies using Northern and slot blot analyses. Analyis of vessel density was performed morphologically and after immunohistochemical staining of endothelial cells., Results: High expression levels were observed in 22/65 tumors. In melanoma, colorectal, gastric, breast and lung cancers only single tumors showed strong expression signals, whereas 7/10 renal cell carcinoma (RCC) xenografts demonstrated high levels of VEGF mRNA. Vessel density analysis revealed a clear correlation of VEGF mRNA expression with vascularization in RCC (p = 0.0048). Patient survival time was compared for tumors showing high versus low expression values. The overall 5-year survival rate was significantly lower for patients with high expression of VEGF mRNA (p = 0.0306)., Conclusions: These data support the hypothesis that tumor cells of various histologies secrete VEGF, which acts as a paracrine factor to induce endothelial cell proliferation and vessel formation and mediates tumor progression.

Background: The EORTC New Drug Development Office has initiated a multicenter collaborative program to evaluate the use of human tumor xenografts to predict phase II clinical activity. A first study confirmed the efficacy of doxorubicin and inactivity of amsacrine against human tumor xenografts (Boven et al., Cancer Res: 52, 5940, 1992). In the follow-up study reported here, the activities of cisplatin, AZQ (diaziquone), pazelliptine and retelliptine have been evaluated against a panel of 40 established tumor lines grown subcutaneously in nude mice., Design: The xenografts used represent carcinomas of the breast, colon, head+neck, ovary, small cell lung cancer (SCLC), non-small cell lung cancer (NSCLC) and melanoma. Drugs were administered intravenously on days 0 and 7. Doses were for cisplatin 5 mg/kg, AZQ 3-7 mg/kg, pazelliptine 20-80 mg/kg and retelliptine 6-12.5 mg/kg and were selected to give a median loss of about 10%-15% body weight., Results: When activity was defined as a specific growth delay > 1 and a tumor growth inhibition > 50%, then cisplatin demonstrated activity in 15 of 40 xenografts tested (3 of 5 breast, 1 of 6 colon, 0 of 5 head+neck, 2 of 6 NSCLC, 4 of 7 SCLC, 1 of 5 melanoma and 4 of 6 ovarian cancers); AZQ was active in 23 of 38 xenografts (2 of 3 breast, 2 of 7 colon, 4 of 5 head+neck, 3 of 6 NSCLC, 6 of 6 SCLC, 2 of 5 melanoma, 4 of 6 ovarian cancers); pazelliptine was active in 2 of 38 xenografts (1 of 5 breast cancers, 1 of 5 melanoma) while retelliptine was active in 1 of 39 xenografts (a breast cancer xenograft) tested., Conclusions: These results are reasonably consistent with the clinical activity of cisplatin, but overpredict the clinical efficacy of AZQ. Since pazelliptine and retelliptine are investigational compounds, the clinical phase II studies will provide a prospective test for this model. The results of the present study and the previous one indicate that the human tumor xenograft model could be suitable for predicting the activity of novel compounds to be developed for treatment of cancer patients.

Rhizoxin is a 16-membered antifungal macrocyclic lactone isolated from the plant pathogenic fungus Rhizopus chinensis. The compound binds to tubulin, preventing microtubule formation, and inhibiting mitosis. It possesses antitumour activity in vivo against various preclinical murine models, both leukaemias and solid tumours model, as well as in vincristine- and doxorubicin-resistant leukaemia lines. In the present study, cytotoxic activity was observed in human tumour cell lines in vitro at very low concentrations (+/- 10(-10) M) particularly against melanoma, colon, renal, non-small cell and small cell lung cancer. In vivo antitumour activity was demonstrated in murine P388 and L1210 murine leukaemias, solid tumour models B16 melanoma and M5076 sarcoma, and in 5 out of 9 human solid tumour xenografts: LOX melanoma, MX-1 breast cancer, non-small cell lung cancer A549, and small cell lung cancers LXFS 605 and LXFS 650. The absence of cross-resistance to vinca alkaloids was confirmed in vivo against the vincristine-resistant P388 leukaemia subline and the vincristine-resistant human small cell lung cancer LXFS 650. In addition, the antitumour activity of rhizoxin was improved by prolonged or repeated drug administration indicating a schedule dependency. In animal toxicology studies, transient changes in erythrocyte and leukocyte numbers, local phlebitis, diarrhea, and spermatogenic arrest were observed. The LD10 value of rhizoxin after a single intravenous injection was 2.8 mg/kg (8.4 mg/m2). One-tenth of the mouse equivalent LD10 (0.84 mg/m2), the starting dose for clinical phase I studies, was considered to be safe in rats.(ABSTRACT TRUNCATED AT 250 WORDS)

The feasibility, evaluation and predictive value of the colony-forming assay with human tumor xenografts for screening anticancer drugs have been studied. Using human tumors grown in serial passage in nude mice, adequate colony formation was observed in 215 of 251 (86%) different solid human tumors of various histologies. Based on in vitro growth characteristics, a quality-controlled assay protocol was developed. With the proposed criteria for standardized evaluation of individual experiments a substantial increase in assay reliability was achieved. The five clinically established agents, cisplatin, doxorubicin, etoposide, mitomycin-C and vindesine, were studied for anticancer activity in the clonogenic assay. Drugs were applied over a wide dose range by continuous exposure, yielding clear dose-response effects with coefficients of correlation between r = 0.946 and 0.995. Relevant dose levels predicting correctly for the clinical efficacy of the agents were determined by comparison of in vitro anticancer activity to in vitro toxicity on human bone marrow as follows: cisplatin 0.1 micrograms/ml, doxorubicin 0.01 micrograms/ml, etoposide 0.1 micrograms/ml, mitomycin-C 0.005 micrograms/ml, vindesine 0.01 micrograms/ml. At these concentrations, clinically sensitive tumor types showed inhibition of colony formation in 99 of 240 cases (41%), whereas 11% (19/176) of clinically resistant tumors were responsive. The relevant dose levels used equal between 0.3% and 4.0% of the achievable peak plasma concentrations in man. The predictive value of the clonogenic assay was determined by treatment of the same tumors in vitro and in vivo in tumor-bearing nude mice. In 174/220 comparisons (79%), in vitro data predicted correctly for the in vivo sensitivity of the xenografted malignancies.(ABSTRACT TRUNCATED AT 250 WORDS)