zd-9331 and Colonic-Neoplasms

ZD9331 is an antifolate drug that potently and specifically inhibits thymidylate synthase (TS). In contrast with TS inhibitors such as raltitrexed, it cannot be polyglutamated, leading to antitumour activity independent of folylpolyglutamyl synthetase (FPGS) activity. The growth inhibition IC50 values for ZD9331 and raltitrexed were determined for a panel of 18 human tumour cell lines, that included six colon and six ovarian. The colon lines largely displayed overlapping sensitivities to both drugs with only one of the six lines being drug resistant. In contrast, the ovarian cell lines displayed non-overlapping sensitivities with four being highly resistant to raltitrexed and only one was cross-resistant to ZD9331. Studies were undertaken to explain these results. The colon and ovarian cell lines were characterised for TS activity, and TS and FPGS mRNA expression. TS activity correlated with sensitivity to ZD9331 (r=0.50; p=0.097) and raltitrexed (r=0.74; p=0.0063). Provided the data from the highly drug-resistant cell lines (BE and 41 M) were omitted, TS mRNA expression levels also correlated with ZD9331 (r=0.77; p=0.013) and raltitrexed IC50 (r=0.84; p=0.0031). FPGS mRNA expression correlated with higher sensitivity to raltitrexed relative to ZD9331 (higher ZD9331/raltitrexed IC50 ratios) (r=0.62; p=0.048). Similarly, cell lines with IC50 ratios>median expressed a 1.8-fold higher median level of FPGS mRNA (p=0.0087) compared with those with ratios

Topics: Antineoplastic Agents; Colonic Neoplasms; Drug Resistance, Neoplasm; Enzyme Inhibitors; Female; Folic Acid Antagonists; Gene Expression; Humans; Ovarian Neoplasms; Peptide Synthases; Quinazolines; RNA, Messenger; RNA, Neoplasm; Thiophenes; Thymidylate Synthase; Tumor Cells, Cultured

To establish the recommended dose (RD) of the thymidylate-synthase inhibitor ZD9331 administered with irinotecan (CPT-11) in patients with pretreated metastatic colorectal cancer, and to assess toxicity profile, pharmacokinetics (PK), and anti-tumor activity in a phase I/II open, multicenter, intrapatient chemotherapy dose escalating trial.. Twenty-one patients who failed first-line therapy (5-fluorouracil/leucovorin +/- oxaliplatin) received every 2 weeks CPT-11 180 mg/m2 D1, followed by ZD9331 30-minute infusion D2 at three dose levels: 90, 120 and 150 mg/m2.. RD of ZD9331 was established at 90 mg/m2 for the first two cycles, with possibility to escalate at 120 mg/m2 according to safety evaluation. Grade 3-4 toxicities were neutropenia (67% of patients), grade 3 vomiting (14%), grade 3 nausea (10%) and grade 3 diarrhea (5%). ZD9331 dose level does not affect the PK of CPT-11 or SN-38. Tumor growth control (PR + SD) was achieved for 14 (66.7%) patients. Median time to progression was 6 months, and median survival was 8.4 months.. ZD9331 90 mg/m2 combined with CPT-11 180 mg/m2 may be a viable option for treatment of metastatic colorectal cancer, with possible escalation to 120 mg/m2 of ZD9331 according to safety evaluation.

Topics: Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Camptothecin; Colonic Neoplasms; Drug Administration Schedule; Female; Humans; Irinotecan; Male; Maximum Tolerated Dose; Middle Aged; Neutropenia; Quinazolines; Rectal Neoplasms

We have demonstrated previously a Fas-dependent component in thymineless death of human colon carcinoma cells. Importantly, the cytotoxic effects of thymidine deprivation induced by 5-fluorouracil (FUra) combined with leucovorin (LV) was enhanced by IFN-gamma, and the synergism was shown to be dependent on Fas, FUra-induced DNA damage, and independent of p53. Subsequently we examined the potential for synergistic interactions between IFN-gamma and the specific thymidylate synthase inhibitor, ZD9331. IFN-gamma sensitized colon carcinomas to ZD9331-induced apoptosis and loss in clonogenic survival, also dependent on ZD9331-induced DNA damage, independent of p53. Synergism occurred in HCT116, demonstrating previously RNA-mediated FUra/LV cytotoxicity that could not be potentiated by IFN-gamma. Manipulation of the Fas death receptor pathway from the level of the receptor (Nok1/Nok2, Fas overexpression, and DN-FADD) to the mitochondria (Bcl-xL and Bcl-2) did not modulate ZD9331 +/- IFN-gamma-induced cytotoxicity in HT29, with the exception that Nok1/Nok2-blocking antibodies partially protected HT29 from the cytotoxic activity of ZD9331 alone. However, IFN-gamma alone (but not ZD9331) up-regulated the expression of caspases -3, -4, -7, and -8, and in combination with ZD9331 demonstrated enhanced caspase activation and cleavage of poly(ADP-ribose) polymerase that was not prevented by overexpression of Bcl-2. Additionally, IFN-gamma increased the activity of the proteasome in HT29, leading to selective down-regulation of the antiapoptotic protein survivin, whereas simultaneously increasing Fas expression. However, reduction in the survivin:Fas ratio by transfection of survivin small interfering RNA and/or overexpression of Fas did not affect sensitivity of HT29 to ZD9331 +/- IFN-gamma. Data demonstrate that IFN-gamma combined with ZD9331 is synergistic in additional cell lines that demonstrate RNA-mediated FUra/LV cytotoxicity, and that a major target of interaction is at the level of caspases, downstream of Fas, and independent of involvement of either the mitochondria or survivin.

Topics: Antineoplastic Agents; Apoptosis; bcl-X Protein; Caspase 3; Caspase 7; Caspase 8; Caspases; Caspases, Initiator; Cell Line; Cell Line, Tumor; Colonic Neoplasms; Cysteine Endopeptidases; DNA, Complementary; Dose-Response Relationship, Drug; Down-Regulation; Enzyme Inhibitors; fas Receptor; Fluorouracil; Gene Expression Regulation, Neoplastic; Humans; Immunoblotting; Inhibitor of Apoptosis Proteins; Interferon-gamma; Kinetics; Microtubule-Associated Proteins; Mitochondria; Multienzyme Complexes; Neoplasm Proteins; Oligonucleotide Array Sequence Analysis; Proteasome Endopeptidase Complex; Proto-Oncogene Proteins c-bcl-2; Quinazolines; Retroviridae; RNA, Small Interfering; Signal Transduction; Survivin; Time Factors; Transfection; Tumor Suppressor Protein p53; Up-Regulation