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Acta Poloniae Pharmaceutica 2005Tezacitabine (FMdC) is a new cytostatic/cytotoxic agent widely investigated in clinical trials and on the cellular level. In a previous paper (3) we worked on human and...
Tezacitabine (FMdC) is a new cytostatic/cytotoxic agent widely investigated in clinical trials and on the cellular level. In a previous paper (3) we worked on human and murine leukemia (L-1210, HL-60, and MOLT-4) cells, and in this paper we investigated the influence of FMdC on the cell cycle and apoptosis in vitro of three other leukemias (CCRF-SB, KG-1, and Jurkat), and human solid tumor (carcinoma) cell lines (COLO-205, MCF-7, and PC-3). We found that FMdC induces the G1 (at concentrations higher than 10 nM). and S-phase (at low concentration) leaky block of the cell cycle. FMdC also effectively induces apoptotic death of cells by the caspase 3/7 pathway. We found also that FMdC induces intensive changes in the protein metabolism. These changes are correlated with the cell death.
Topics: Animals; Antineoplastic Agents; Apoptosis; Cell Line, Tumor; Deoxycytidine; G1 Phase; Humans; Jurkat Cells; Mice; S Phase
PubMed: 16193812
DOI: No ID Found -
Acta Biochimica Polonica 2005The aim of the study was to determine the relation between the cytotoxic and cytostatic effects of tezacitabine and cladribine on a HL-60 cell line and the time of...
The aim of the study was to determine the relation between the cytotoxic and cytostatic effects of tezacitabine and cladribine on a HL-60 cell line and the time of exposure of cells to these drugs. Cell viability and induction of apoptosis were assessed using flow cytometry methods. Apoptosis was confirmed by direct microscopic observation. Growth inhibition was examined by cell counting. After 24 h incubation tezacitabine was equally or less toxic compared to cladribine. However, toxicity of tezacitabine strongly rose after 48 h incubation leading to massive cell death at doses much lower than those of cladribine. Assessment of the effect of increased exposure time on the clinical efficacy of tezacitabine is indicated.
Topics: Antineoplastic Agents; Apoptosis; Cell Survival; Cladribine; Deoxycytidine; Flow Cytometry; HL-60 Cells; Humans
PubMed: 15933759
DOI: No ID Found -
Cancer May 2005Tezacitabine [(E)-2'-deoxy-2'-(fluoromethylene) cytidine; FMdC] is a novel nucleoside analog with potent antiproliferative and antitumor activity in preclinical studies.... (Clinical Trial)
Clinical Trial
BACKGROUND
Tezacitabine [(E)-2'-deoxy-2'-(fluoromethylene) cytidine; FMdC] is a novel nucleoside analog with potent antiproliferative and antitumor activity in preclinical studies. A tolerable safety profile and clinical activity have been shown in Phase I and Phase II clinical studies. The purpose of the current open-label, Phase I dose-escalation trial was to evaluate the combination of tezacitabine and 5-fluorouracil (5-FU) in the treatment of patients with advanced solid tumors.
METHODS
Twenty-four patients with a variety of advanced solid tumors for which there was no curative therapy were enrolled. Bolus infusion tezacitabine was administered on Day 1 of a 14-day cycle at escalating doses of 150-350 mg/m(2), with continuous infusion 5-FU (CI 5-FU) given on Days 1-7 at a fixed dose of 200 mg/m(2) per day. Patients underwent objective tumor evaluation by radiologic methods or clinical examination at baseline and after every fourth treatment cycle.
RESULTS
The maximum tolerated dose of the combination therapy was determined to be tezacitabine, 200 mg/m(2), with CI 5-FU, 200 mg/m(2) per day. The toxicities were manageable, the most notable being transient severe (National Cancer Institute Common Toxicity Criteria Grade 3 or 4) neutropenia in 23 patients (96%). Eleven (55%) of the 20 assessable patients had partial responses or stabilization of disease. The highest response rate was in patients with primary tumors of esophageal origin.
CONCLUSIONS
Tezacitabine at a dose of 200 mg/m(2) in combination with CI 5-FU at a dose of 200 mg/m(2) per day was relatively well tolerated and had clinical activity in patients with advanced solid tumors, particularly in patients with esophageal and other gastrointestinal carcinomas.
Topics: Aged; Antineoplastic Combined Chemotherapy Protocols; Deoxycytidine; Dose-Response Relationship, Drug; Female; Fluorouracil; Humans; Male; Maximum Tolerated Dose; Middle Aged; Neoplasms; Treatment Outcome
PubMed: 15772958
DOI: 10.1002/cncr.21002 -
Acta Poloniae Pharmaceutica 2004Physiologic deoxynucleotides are required for an error-proof DNA replication, repair and synthesis. Any inaccuracy in this process results in a block in DNA synthesis... (Review)
Review
Physiologic deoxynucleotides are required for an error-proof DNA replication, repair and synthesis. Any inaccuracy in this process results in a block in DNA synthesis until the error is corrected. If the cell enzymes are unable to correct the error, a signal for apoptosis is generated. This mechanism is the main target for anticancer nucleoside analogs. They also interact with the metabolism of physiological nucleosides, and consequently, have a large number of intracellular targets to induce cytotoxicity. In addition, it is now reported that some analogs may interfere directly with RNA synthesis. A great deal of synthesized nucleoside analogs provide the opportunity to understand the structure-based differences in their metabolism and mechanisms of action as well as to identify the specific intracellular targets and diseases, in which each of these newer nucleoside analogs acts most efficiently. This paper summarizes developments in the area of new nucleoside analogs undergoing clinical evaluation for the treatment of solid tumors, namely tezacitabine, troxacitabine, DMDC, CNDAC, ECyD, clofarabine, and decitabine.
Topics: Adenine Nucleotides; Animals; Antineoplastic Agents; Arabinonucleosides; Azacitidine; Clinical Trials as Topic; Clofarabine; Cytarabine; Cytidine; Cytosine; Decitabine; Deoxycytidine; Dioxolanes; Humans; Neoplasms; Nucleosides
PubMed: 15575597
DOI: No ID Found -
Acta Poloniae Pharmaceutica 2004Cytotoxic nucleoside analogs have a broad clinical use. They were among the first chemotherapeutic agents used in the treatment of malignant diseases. The anticancer... (Review)
Review
Cytotoxic nucleoside analogs have a broad clinical use. They were among the first chemotherapeutic agents used in the treatment of malignant diseases. The anticancer nucleosides include analogs of physiologic pyrimidine and purine nucleosides. They are used in oncology in the treatment of both, solid tumors and hematological malignancies. These agents have many intracellular targets, e.g. they act as antimetabolites, competing with natural nucleosides during DNA or RNA synthesis and as inhibitors of key cell enzymes. Understanding of the mechanisms of action of these compounds and synthesis of new analogs provides the possibility to further expand the spectrum of their clinical use and enhance their antitumor activity. In this paper we describe mechanisms of action and possible clinical use in the treatment of hematological malignancies of these nucleoside analogs, which are now in different stages of clinical trials, namely tezacitabine, troxacitabine, clofarabine, nelarabine, decitabine, CNDAC and ECyD.
Topics: Adenine Nucleotides; Animals; Antineoplastic Agents; Arabinonucleosides; Clinical Trials as Topic; Clofarabine; Cytarabine; Cytosine; Deoxycytidine; Dioxolanes; Half-Life; Hematologic Neoplasms; Humans; Purine Nucleosides; Pyrimidine Nucleosides; Stereoisomerism
PubMed: 15481249
DOI: No ID Found -
NMR in Biomedicine Apr 2003(E)-2'-deoxy-2'-(fluoromethylene)cytidine (FMdC), was evaluated as a potential treatment for malignant gliomas using the rat 9L brain tumor model. FMdC was shown to be...
(E)-2'-deoxy-2'-(fluoromethylene)cytidine (FMdC), was evaluated as a potential treatment for malignant gliomas using the rat 9L brain tumor model. FMdC was shown to be an effective inhibitor of cell proliferation in cultured 9L cells with an EC(50) of 40 ng/ml. In vitro studies also revealed that this compound significantly inhibited incorporation of [(3)H]thymidine in 9L cells. In vivo therapeutic efficacy of FMdC was evaluated in rats harboring intracerebral 9L tumors which were treated daily with 15 mg/kg, i.p. Treatment response was quantified from changes in tumor growth rates as assessed from sequential magnetic resonance imaging (MRI) tumor volume measurements. In vivo tumor cell kill in individual animals was calculated by fitting tumor volume data with an iterative computer routine. It was estimated that therapeutically responsive rats treated with FMdC daily produced a >/= 0.1 log kill per therapeutic dose which resulted in a significant reduction in tumor growth rate. In addition, localized (1)H-MRS of intracerebral 9L tumors revealed changes in metabolite levels which correlated with therapeutic response. These results provide evidence supporting the use of FMdC in clinical trials for the treatment of malignant gliomas and reveals that MR can play an important role in the pre-clinical evaluation of novel compounds using orthotopic tumor models.
Topics: Animals; Antineoplastic Agents; Apoptosis; Brain Neoplasms; Cell Division; Cell Line, Tumor; Cell Survival; Deoxycytidine; Dose-Response Relationship, Drug; Feasibility Studies; Glioma; Imaging, Three-Dimensional; Injections, Intraperitoneal; Magnetic Resonance Imaging; Male; Neoplasm Transplantation; Protons; Rats; Rats, Inbred F344; Thymidine; Treatment Outcome
PubMed: 12730947
DOI: 10.1002/nbm.813 -
Cancer Apr 2003The authors performed a dose escalation study of cisplatin and the novel deoxycytidine analog, tezacitabine, to determine the maximum tolerated dose of the combination. (Clinical Trial)
Clinical Trial
BACKGROUND
The authors performed a dose escalation study of cisplatin and the novel deoxycytidine analog, tezacitabine, to determine the maximum tolerated dose of the combination.
METHODS
Twenty-three patients with advanced cancer and good performance status were accrued to 3 dose levels of tezacitabine (150-270 mg/m(2)) and cisplatin (50 mg/m(2)). Using a 28-day treatment cycle, both drugs were administered on Days 1 and 15.
RESULTS
Hematologic toxicity was the most frequently observed side effect and was dose limiting. Grade 3 or 4 neutropenia and thrombocytopenia complicated 75% and 31% of all cycles, respectively. Nonhematologic toxicities were mild. Among 18 evaluable patients, 2 with upper gastrointestinal tract tumors achieved partial responses and 4 had stable disease.
CONCLUSIONS
Based on dose-limiting neutropenia and thrombocytopenia at the highest dose level, the recommended Phase II doses are 200 mg/m(2) of tezacitabine and 50 mg/m(2) of cisplatin.
Topics: Adult; Aged; Aged, 80 and over; Antineoplastic Combined Chemotherapy Protocols; Cisplatin; Deoxycytidine; Dose-Response Relationship, Drug; Female; Humans; Male; Middle Aged; Neoplasms; Treatment Outcome
PubMed: 12673728
DOI: 10.1002/cncr.11273 -
Acta Biochimica Polonica 2000(E)-2'-deoxy-2'-(fluoromethylene)-cytidine (FMdC), a deoxycytidine analog displaying a very high toxicity toward a variety of solid tumor cell lines and xenografts, is...
(E)-2'-deoxy-2'-(fluoromethylene)-cytidine (FMdC), a deoxycytidine analog displaying a very high toxicity toward a variety of solid tumor cell lines and xenografts, is activated intracellularly by deoxycytidine kinase (dCK). We have compared cytotoxicity of FMdC towards a human promyeolocytic leukemia line HL-60 and a human colorectal carcinoma line COLO-205. Despite dCK activity being by far the highest in cells of lymphoid origin, the effects of FMdC were detectable at the lowest drug concentration only in a solid tumor cell line, and at higher concentrations they were qualitatively similar in the two tumor lines (increased cell protein content, cell cycle block and apoptosis). Apparently, low dCK activity in solid tumor cells sufficiently activates FMdC to yield cytotoxic effects, while high dCK activity in leukemia cells does not increase its cytotoxicity.
Topics: Antineoplastic Agents; Colorectal Neoplasms; Deoxycytidine; Drug Screening Assays, Antitumor; HL-60 Cells; Humans; Leukemia, Promyelocytic, Acute; Tumor Cells, Cultured
PubMed: 10961690
DOI: No ID Found -
Cytometry Dec 1999(E)-2'-deoxy-2'-(fluoromethylene)-cytidine (FMdC), an irreversible inhibitor of ribonucleotide reductase, displays a strong toxicity towards many cell lines derived from...
BACKGROUND
(E)-2'-deoxy-2'-(fluoromethylene)-cytidine (FMdC), an irreversible inhibitor of ribonucleotide reductase, displays a strong toxicity towards many cell lines derived from human solid tumors, while its activity on leukemia lines is less well-known. The aim of this study was to assess the effect of FMdC on the cell cycle and cell death of human leukemia lines HL-60 and MOLT-4, and murine leukemia L-1210 in vitro. It has been assumed that a prerequisite of FMdC cytotoxicity is intracellular phosphorylation by deoxycytidine kinase (dCK).
METHODS
Cell cultures in the exponential phase of growth were exposed to different concentrations of FMdC (10 nM to 10 microM) for 6 and 24 hours. In a parallel set of experiments 1 mM deoxycytidine was added to prevent phosphorylation of the drug by dCK. The DNA and protein content in the cells, as well as Annexin V/PI binding were assessed by flow cytometry. The cell cycle was analyzed by the MacCycle software.
RESULTS
The cytotoxic effects of FMdC, i.e., G(1)/S block and cell death were observed, associated with pronounced changes in the protein content. These effects were of variable intensity among the cell lines studied (HL-60 being the most susceptible), and in some cases, were not completely reversed by deoxycytidine excess.
CONCLUSIONS
FMdC is a potent cytotoxic/cytostatic agent against human leukemia cell lines in vitro. It also changes the cellular protein content. Unphosphorylated FMdC may slightly influence the cell cycle of some leukemic lines.
Topics: Animals; Annexin A5; Antineoplastic Agents; Cell Death; DNA, Neoplasm; Deoxycytidine; Flow Cytometry; G1 Phase; HL-60 Cells; Humans; Leukemia, Lymphoid; Mice; Neoplasm Proteins; Phosphorylation
PubMed: 10547615
DOI: 10.1002/(sici)1097-0320(19991201)37:4<302::aid-cyto7>3.0.co;2-7 -
Analytical Biochemistry May 1999Simultaneous determination of ribonucleoside and deoxyribonucleoside triphosphates in cells by HPLC is an analytical challenge since the concentration of dNTP present in...
Simultaneous determination of ribonucleoside and deoxyribonucleoside triphosphates in cells by HPLC is an analytical challenge since the concentration of dNTP present in mammalian cells is several orders of magnitude lower than the corresponding NTP. Hence, the quantitation of dNTP in cells is generally performed after selective oxidation or removal of the major NTP. The procedures reported so far are lengthy and cumbersome and do not enable the simultaneous determination of NTP. We report the development of a simple, direct HPLC method for the simultaneous determination of dNTP and NTP in colon carcinoma WiDr cell extracts using a stepwise gradient elution ion-pairing HPLC with uv detection at 260 nm and with a minimal chemical manipulation of cells. Exponentially growing WiDr cells were harvested by centrifugation, rinsed with phosphate-buffered saline, and carefully counted. The pellets were suspended in a known volume of ice-cold water and deproteinized with an equal volume of 6% trichloroacetic acid. The acid cell extracts (corresponding to 2. 5 x 10(6) cells/100 microl) were centrifuged at 13,000g for 10 min at 4 degrees C. The resulting supernatants were stored at -80 degrees C prior to analysis. Aliquots (100 microl) were neutralized with 4.3 microl saturated Na2CO3 solution prior the injection of 40 microl onto the HPLC column (injection speed 250 microl/min). Chromatographic separations were performed using two Symmetry C18 3. 5-microm (2 x 3.9 x 150 mm) columns (Waters), connected in series equipped with a Sentry guard column (3.9 x 20 mm i.d.) filled with the same packing material. The HPLC columns were kept at 30 degrees C. The mobile phase was delivered at a flow rate of 0.5 ml/min, with the following stepwise gradient elution program: % solvent A/solvent B, 100/0 at 0 min --> 100/0 at 1 min --> 36/64 at 5 min --> 31/69 at 90 min --> 31/69 at 105 min --> 0/100 at 106 min --> 0/100 at 120 min; 50/50 MeOH/solvent B from 121 to 130 min; 100% solvent A from 131 to 160 min. Solvent A contained 0.01 M KH2PO4, 0.01 M tetrabutylammonium chloride, and 0.25% MeOH and was adjusted to pH 7. 0 (550 microl 10 N NaOH for 1 liter solvent A). Solvent B consisted of 0.1 M KH2PO4, 0.028 M tetrabutylammonium chloride, and 30% MeOH and was neutralized to pH 7.0 (1.4 ml 10 N NaOH for 1 liter solvent B). Even though dNTPs are minor components of cell extracts, satisfactory regression coefficients were obtained for their calibration curves (r2 > 0.99) established with the addition-calibration methods up to 120 pmol/40-microl injection. The applicability of the method was demonstrated by in vitro studies of the modulation of NTP and dNTP pools in WiDr colon carcinoma cell lines exposed to various pharmacological concentrations of cytostatic drugs (i.e., FMdC, IUdR, gemcitabine). In conclusion, this optimized, simplified, analytical method enables the simultaneous quantitation of NTP and dNTP and may represent a valuable tool for the detection of minute alterations of cellular dNTP/NTP pools induced by anticancer/antiviral drugs and diseases.
Topics: Chromatography, High Pressure Liquid; Deoxycytidine; Deoxyribonucleosides; Enzyme Inhibitors; Humans; Ribonucleotide Reductases; Tumor Cells, Cultured
PubMed: 10328765
DOI: 10.1006/abio.1999.4066