demecolcine and Neoplasms

Topics: Biopsy, Needle; Bone Marrow Examination; Cells, Cultured; Centrifugation, Density Gradient; Clone Cells; Cryopreservation; Demecolcine; Ficoll; Flow Cytometry; Fluorescent Antibody Technique, Direct; Fluorescent Dyes; Humans; Immunomagnetic Separation; Metaphase; Microspheres; Neoplasms; Neoplastic Stem Cells

Pentaploid H1 (ES) cells (5H1 cells) were accidentally obtained through one-cell cloning of octaploid H1 (ES) cells (8H1 cells) that were established from tetraploid H1 (ES) cells (4H1 cells) polyploidized using demecolcine. The number of chromosomes of 5H1 cells was 100, unlike the 40 of diploid H1 (ES) cells (2H1 cells), 80 of 4H1, and 160 of 8H1 cells. The durations of G(1), S, and G(2)/M phases of 5H1 cells were 3, 7, and 6 h, respectively, almost the same as those of 2H1, 4H1, and 8H1 cells. The cell volume of 5H1 cells was half of that of 8H1 cells, suggesting that 5H1 cells were created through abnormal cell divisions of 8H1 cells. The morphology of growing 5H1 cells was a spherical cluster similar to that of 2H1 cells and differing from the flagstone-like shape of 4H1 and 8H1 cells. Pentaploid solid tumors were formed from 5H1 cells after interperitoneal injection into the mouse abdomen, and they contained endodermal, mesodermal, and ectodermal cells as well as undifferentiated cells, suggesting both that the DNA content of 5H1 cells was retained during tumor formation and that the 5H1 cells were pluripotent. The DNA content of 5H1 cells was stable in long-term culturing as 2H1 cells, meaning that 5H1 and 2H1 cells shared similarities in DNA structure. The excellent stability of the DNA content of 5H1 cells was explained using a hypothesis for the DNA structure of polyploid cells because the pairing of homologous chromosomes in 5H1 cells is spatially forbidden.

Topics: Animals; Antineoplastic Agents, Phytogenic; Cell Culture Techniques; Cell Differentiation; Cell Division; Cell Lineage; Cell Transformation, Neoplastic; Cells, Cultured; Chromosomal Instability; Chromosome Aberrations; Demecolcine; DNA; Gene Expression Regulation, Neoplastic; Mice; Neoplasms; Pluripotent Stem Cells; Polyploidy; Stem Cell Transplantation

Current microtubule inhibitory agents used in the clinic to treat cancer have severe side effects, and development of resistance is frequent. We have evaluated the antitumor effect of a novel 30-compound library of phenoxy pyridine and phenyl sulfanyl pyridine derivatives. MTT assays revealed that, of all 30 compounds tested, compounds 2 and 3 showed the largest decrease in proliferation (low muM range) against Panc1 and HS766T human pancreatic cancer cells. Flow cytometry experiments with MCF7 breast cancer cells showed a G2/M arrest comparable to that of colcemid. Immunofluorescence staining demonstrated complete disappearance of intracellular microtubules. Tubulin assembly assays, however, showed a dose-dependent decrease in tubulin assembly with compound 3 that seemed limited to about 50% of the control reaction. With compound 2 treatment, there was only a delay in the onset of assembly, with no effect on the extent of the reaction. Taken together, our results show that these novel microtubule inhibitors have promising anticancer activity and can be potentially used to overcome paclitaxel resistance in the clinical setting.

Topics: Antineoplastic Agents; Cell Line, Tumor; Cell Proliferation; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Flow Cytometry; Fluorescent Antibody Technique; Humans; Microtubules; Molecular Structure; Neoplasms; Pyridines; Small Molecule Libraries; Stereoisomerism; Structure-Activity Relationship; Tubulin

c-myc has been shown to regulate G(1)/S transition, but a role for c-myc in other phases of the cell cycle has not been identified. Exposure of cells to colcemid activates the mitotic spindle checkpoint and arrests cells transiently in metaphase. After prolonged colcemid exposure, the cells withdraw from mitosis and enter a G(1)-like state. In contrast to cells in G(1), colcemid-arrested cells have decreased G(1) cyclin-dependent kinase activity and show hypophosphorylation of the retinoblastoma protein. We have found that overexpression of c-myc causes colcemid-treated human and rodent cells to become either apoptotic or polyploid by replicating DNA without chromosomal segregation. Although c-myc-induced polyploidy is not inhibited by wild-type p53 in immortalized murine fibroblasts, overexpression of c-myc in primary fibroblasts resulted in massive apoptosis of colcemid-treated cells. We surmise that additional genes are altered in immortalized cells to suppress the apoptotic pathway and allow c-myc-overexpressing cells to progress forward in the presence of colcemid. Our results also suggest that c-myc induces DNA rereplication in this G(1)-like state by activating CDK2 activity. These observations indicate that activation of c-myc may contribute to the genomic instability commonly found in human cancers.

Topics: Animals; Apoptosis; Cell Cycle; Cell Line, Transformed; Cyclin-Dependent Kinase 4; Cyclin-Dependent Kinases; Demecolcine; DNA Replication; Fibroblasts; Gene Expression Regulation; Genes, myc; Genes, p53; Genes, ras; Genes, Retinoblastoma; Humans; Mitosis; Models, Biological; Neoplasms; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-myc; Rats; Recombinant Fusion Proteins; Spindle Apparatus

Genetic instability was one of the first characteristics to be postulated to underlie neoplasia. Such genetic instability occurs in two different forms. In a small fraction of colorectal and some other cancers, defective repair of mismatched bases results in an increased mutation rate at the nucleotide level and consequent widespread microsatellite instability. In most colorectal cancers, and probably in many other cancer types, a chromosomal instability (CIN) leading to an abnormal chromosome number (aneuploidy) is observed. The physiological and molecular bases of this pervasive abnormality are unknown. Here we show that CIN is consistently associated with the loss of function of a mitotic checkpoint. Moreover, in some cancers displaying CIN the loss of this checkpoint was associated with the mutational inactivation of a human homologue of the yeast BUB1 gene; BUB1 controls mitotic checkpoints and chromosome segregation in yeast. The normal mitotic checkpoints of cells displaying microsatellite instability become defective upon transfer of mutant hBUB1 alleles from either of two CIN cancers.

Topics: Amino Acid Sequence; Aneuploidy; Antineoplastic Agents; Cell Cycle; Cloning, Molecular; Colorectal Neoplasms; Demecolcine; Humans; Mitosis; Mitotic Index; Molecular Sequence Data; Mutation; Neoplasms; Nocodazole; Protein Kinases; Protein Serine-Threonine Kinases; Transfection; Tumor Cells, Cultured

Topics: Animals; Antineoplastic Agents; Aphidicolin; Cell Cycle; Cell Line; Demecolcine; DNA; Drug Resistance; Gamma Rays; Gene Amplification; Humans; Mitosis; Neoplasms

Ascorbate ions induced a polarization peak in the intracellular fluorescein fluorescence polarization spectra of asynchronous populations of a variety of cancer cell types from human and animal biopsy material or in cells grown in vivo and/or in vitro. The appearance of this polarization peak at 510 nm on excitation at 470 nm (P510 peak) indicates the transition of mitochondria from the condensed (active) into orthodox (resting) conformation. In contrast, no effects of ascorbate ions were observed in the polarization spectra of various normal cell lines. This apparent differential response seems to be caused by the effects of ascorbate ions on several steps of the altered energy metabolism in cancer cells. It appeared not to be due to a defective mechanism responsible for the conformational changes in the mitochondria. In YMDR cells resistant to the antitumor drug methylene-dimethanesulphonate (MDMS), HeLa cells pretreated with colcemid, and YMDS cells pretreated with cytochalasin B, the transition of mitochondria into orthodox conformation could not be induced by ascorbate ions. Thus, it is possible that tumors also pretreated with other drugs become resistant to growth inhibitory effects of ascorbate ions. Induction of the fluorescein emission polarization peak at 510 nm in cells from biopsies or from in vitro-induced malignancies could be used as an additional criterion for malignant transformation.

Topics: 2,4-Dinitrophenol; Ascorbic Acid; Calcium; Cell Line; Cyclic AMP; Cytochalasin B; Demecolcine; Dinitrophenols; Energy Metabolism; Fluorescence Polarization; Glycolysis; Humans; Hydrogen-Ion Concentration; Interphase; Methyl Methanesulfonate; Mitochondria; Neoplasms

Topics: Antineoplastic Combined Chemotherapy Protocols; Combined Modality Therapy; Demecolcine; Evaluation Studies as Topic; Humans; Hyperthermia, Induced; Melphalan; Neoplasms; Radiotherapy Dosage

Micronucleation was induced by vincristine, colcemid, and colcemid in combination with cytochalasin B in cells of a human metastatic breast carcinoma cell line (MDA MB 231). Cells treated with the latter combination were enucleated subsequently by centrifugation in the presence of cytochalasin B. The resulting "microcell" fraction was fused with mitotic human primary fibroblasts or mitotic HeLa cells using polyethyleneglycol (PEG). The success of the microcell-mediated chromosome transfer thus could be demonstrated as premature condensation in the mitotic recipient of the transferred micronuclei. This technique of cytogenetic analysis allowed a fast and simple control of the influence of different conditions on micronucleation and fusion of micronuclei with recipient cells. It could be shown that microcell-mediated chromosome transfer from human tumor cells into human normal, as well as human tumor, recipient cells is practicable if the techniques figured out by the present study are employed.

Topics: Breast Neoplasms; Cell Fusion; Cell Line; Cell Nucleus; Chromosomes, Human; Cytochalasin B; Demecolcine; Female; Genetic Engineering; Genetic Vectors; HeLa Cells; Humans; Neoplasms; Polyethylene Glycols; Vincristine

Time-lapse cinemicrography was employed for the study of the early behaviour of normal and neoplastic rat cells seeded upon the grooved surface. Lewis rat embryo fibroblasts and two neoplastic clonal lines, fibroblastoid LW13K2 and epithelioid RsK4, were used. Although all cells were spheroids of approximately the same size, differences in their subsequent behaviour was found. LWF cells showed minimal surface motility, produced protrusions towards the side slopes of the groove only and migrated after the reliable attachment had been established, even in the non-well-spread form, directly off the groove. Some LW13K2 cells showed increased surface motility of the zeiotic type. Attachment was attempted at the side slopes of the groove only with subsequent migration from the groove. Migration of LW13K2 in comparison with normal fibroblasts was less directional as they eventually returned to the groove bottom. RsK4 cells were seen already scattered around the bottom of the groove in the non-well-spread form with zeiotic activity. Oscillation of the whole cell was observed which is suspected to cause their displacement off the groove by elastic rebounding from each other just after seeding. They completed spreading into a polygonal form within an hour and a half after seeding, even at the bottom of the groove. Colcemid treatment did not substantially alter migration of either cells off the groove. Vacuum coating of the grooved surface with carbon strengthened cell-to-substrate adhesion. Thus the diminished adhesiveness of the surface at the bottom of the groove and its particular geometrical configuration make the substrate in the direction parallel to the groove bottom less accessible to contacts with the cell surface. These factors together with different adhesiveness and organization of contractile structures of neoplastic cells appeared to be responsible for their decreased migration from the groove.

Topics: Animals; Carbon; Cell Line; Cell Movement; Clone Cells; Demecolcine; Fibroblasts; Microscopy; Motion Pictures; Neoplasm Seeding; Neoplasms; Rats; Time Factors

The literature concerning the use of metaphase inducing agents as clinical sensitisers to radiation is briefly reviewed, and five cases are reported, which suggest that under ordinary clinical conditions, these agents are not likely to be of value. These results accord with animal experiments and a possible reason is suggested.

Topics: Adenocarcinoma; Adult; Aged; Anus Neoplasms; Carcinoma, Squamous Cell; Demecolcine; Female; Humans; Lip Neoplasms; Male; Middle Aged; Mitotic Index; Neoplasms; Radiation-Sensitizing Agents; Skin Neoplasms; Stomach Neoplasms

Topics: Adenosine Monophosphate; Adenosine Triphosphatases; Cell Count; Demecolcine; Growth Inhibitors; Kinetics; Mitosis; Neoplasms; Nucleotidases; Thymidine; Tritium; Vinblastine

Topics: Bronchial Neoplasms; Carcinoma; Carcinoma, Squamous Cell; Cell Division; Colchicine; Demecolcine; Drug Therapy; Female; Humans; Mediastinum; Neoplasm Metastasis; Neoplasms; Prognosis; Skin Neoplasms; Thoracic Diseases; Uterine Cervical Neoplasms

Topics: Colchicine; Demecolcine; Drug Therapy; Leukemia; Neoplasms

Topics: Administration, Oral; Antineoplastic Agents; Demecolcine; Drug Synergism; Esophagus; Gastrointestinal Neoplasms; Geriatrics; Humans; Melphalan; Neoplasms; Palliative Care; Rectum; Stomach Neoplasms

Topics: Biological Assay; Body Fluids; Colchicine; Demecolcine; Neoplasms; Tissue Culture Techniques

Topics: Breast; Breast Neoplasms; Colchicine; Demecolcine; Humans; Neoplasms; Radiotherapy

Topics: Colchicine; Demecolcine; Hematologic Diseases; Leukemia; Neoplasms

Topics: Colchicine; Demecolcine; Leukemia; Leukemia, Myeloid; Neoplasms

Topics: Antineoplastic Agents; Colchicine; Cytostatic Agents; Demecolcine; Neoplasms