demecolcine and Adenocarcinoma

The molecular basis for the sensitivity of tumor cells to chemopreventive natural food compounds and commonly used chemotherapeutic agents is not well understood, not least because studies are frequently confounded by the diversity among cell lines or rely on experimental protein overexpression. Here we investigated the effects of n-butyrate, a cancer-preventive short-chain fatty acid produced by anaerobic bacteria in the gastrointestinal tract, on the human wild-type p53 and p21 expressing HCT116 colon carcinoma cell line and on HCT116 cells with either p53 or p21 alleles inactivated by homologous recombination. The effects of n-butyrate were then compared with those elicited by cytotoxic drugs and the natural chemopreventive phytoalexin of wine and grapes, resveratrol. We document that physiological concentrations of n-butyrate stimulate p21 expression and induce apoptosis independently of p53, and that the absence of p21 increases apoptosis drastically. The apoptosis is mediated through the mitochondria and is accompanied by mitochondrial proliferation and membrane potential changes. Adriamycin, etoposide, cisplatinum, colcemid and resveratrol induce distinct cellular responses; however, absence of p21 favors apoptosis-induction by adriamycin, etoposide and colcemid. Thus, control of p21 expression may support chemoprevention and certain tumor therapies.

Topics: Adenocarcinoma; Alleles; Amino Acid Chloromethyl Ketones; Anticarcinogenic Agents; Antineoplastic Agents; Apoptosis; Benzothiazoles; Butyrates; Cisplatin; Colonic Neoplasms; Cyclin-Dependent Kinase Inhibitor p21; Cyclins; Cysteine Proteinase Inhibitors; Demecolcine; Doxorubicin; Drug Resistance, Neoplasm; Etoposide; Fluorouracil; Gene Expression Regulation, Neoplastic; Genes, p53; Humans; Intracellular Membranes; Membrane Potentials; Mitochondria; Neoplasm Proteins; Recombination, Genetic; Resveratrol; Stilbenes; Thiazoles; Toluene; Tumor Cells, Cultured; Tumor Suppressor Protein p53

The EWS/FLI-1 fusion gene is characteristic of most cases of Ewing's sarcoma and has been shown to be crucial for tumor transformation and cell growth. In this study we demonstrate a drastic down-regulation of the EWS/FLI-1 protein, and a growth arrest, following serum depletion of Ewing's sarcoma cells. This indicates that growth factor circuits may be involved in regulation of the fusion gene product. Of four different growth factors tested, basic fibroblast growth factor (bFGF) was found to be of particular significance. In fact, upon treatment of serum-depleted cells with bFGF, expression of the EWS/FLI-1 protein and growth of the Ewing's sarcoma cells were restored. In addition, a bFGF-neutralizing antibody, which was confirmed to inhibit FGF receptor (FGFR) phosphorylation, caused down-regulation of EWS/FLI-1. Experiments using specific cell cycle blockers (thymidine and colcemide) suggest that EWS/FLI-1 is directly linked to bFGF stimulation, and not indirectly to cell proliferation. We also demonstrated expression of FGFRs in several tumor samples of Ewing's sarcoma. Taken together, our data suggest that expression of FGFR is a common feature of Ewing's sarcoma and, in particular, that the bFGF pathway may be important for the maintenance of a malignant phenotype of Ewing's sarcoma cells through up-regulating the EWS/FLI-1 protein. Oncogene (2000) 19, 4298 - 4301

Topics: Adenocarcinoma; Antibodies, Monoclonal; Bone Neoplasms; Cell Cycle; Cell Division; Chromosomes, Human, Pair 11; Chromosomes, Human, Pair 22; Culture Media, Serum-Free; Demecolcine; Drug Synergism; Epidermal Growth Factor; Fibroblast Growth Factor 2; Fibroblasts; Gene Expression Regulation, Neoplastic; Humans; Insulin-Like Growth Factor I; Male; Neoplasm Proteins; Oncogene Proteins, Fusion; Platelet-Derived Growth Factor; Prostatic Neoplasms; Proto-Oncogene Protein c-fli-1; Receptors, Fibroblast Growth Factor; RNA-Binding Protein EWS; Sarcoma, Ewing; Thymidine; Transcription Factors; Translocation, Genetic; Tumor Cells, Cultured

Alterations in mouse mammary tumor virus (MMTV) production and composition were induced by exposure of mammary tumor cells to cytodisruptive agents. Treatment with 2.1 microM cytochalasin D (CD) for 24 h reduced MMTV yield by 80% and electron microscopic examination of these cells did not reveal budding virions. Immune precipitation and quantitative immunofluorescence studies demonstrated that CD had no significant effect on MMTV polypeptide synthesis or surface expression suggesting that CD inhibited late steps in MMTV maturation. Decreases in MMTV production were also observed as a result of 24 h exposure of the cells to 2.1 microM cytochalasin B (CB). However, an initial 70% increase in the levels of extracellular virions within the first 18 h of treatment preceded diminution of virus production. In addition, CB was unable to abrogate maturation and release of MMTV particles as revealed by electron microscopic evaluation of thin sections of treated cells. Colcemid at 0.28 microM had no effect on virus production during the first 24 h of exposure although MMTV yield was reduced by 60-70% after 36 h of treatment. Polypeptide profiles of MMTV purified from cell cultures treated with any of the three cytodisruptive agents were altered and included 5-7 polypeptides not typically present in MMTV from untreated cells. These cytodisruptive agents did not significantly affect viability and protein metabolism of MJY-alpha cells; the data suggest that alterations in MMTV replication were due to disruption of the cellular cytoskeleton.

Topics: Adenocarcinoma; Animals; Antigens, Viral; Cytochalasin B; Cytochalasin D; Cytochalasins; Cytoskeleton; Demecolcine; Female; Mammary Neoplasms, Experimental; Mammary Tumor Virus, Mouse; Mice; Mice, Inbred BALB C; Viral Proteins; Virion; Virus Replication

The lethal and cytokinetic effects of mitomycin C (MC) as a function of drug concentration and exposure time were assessed in cultured human colon adenocarcinoma (LoVo) cells using colony formation to determine cell survival and DNA flow cytometry to examine cell cycle perturbation. MC evoked threshold-exponential type 1-hr dose-dependent survival curves in both exponential and stationary growth phases (Dq = 0.4 microgram/ml; Do = 1.0 microgram/ml). In exponentially growing cultures, a given exposure dose of MC induced equitoxic effects regardless of the specific drug concentration and exposure time used with uninterrupted treatment. However, dose fractionation experiments revealed the ability of LoVo cells to partially repair sublethal damage from MC exposure. Cell cycle progression was reversibly delayed or blocked in G2, S, and G1 phases in this order of sensitivity, with a frozen cycle distribution after greater than or equal to 24 hr treatment with 5 microgram of MC per ml. The reversible delay in S-phase traverse without a significant subsequent G2 block may be exploitable for administration of S-phase-specific drugs to maximize cell kill.

Topics: Adenocarcinoma; Cell Cycle; Cell Line; Cell Survival; Colonic Neoplasms; Demecolcine; Dose-Response Relationship, Drug; Drug Administration Schedule; Humans; Interphase; Mitomycins; Neoplasms, Experimental

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: Adenocarcinoma; Animals; Cell Division; Cell Nucleus; Demecolcine; Dose-Response Relationship, Drug; Female; Mammary Glands, Animal; Mammary Neoplasms, Experimental; Mathematics; Mice; Mice, Inbred CBA; Neoplasm Transplantation; Time Factors; Vincristine

Topics: Adenocarcinoma; Aneuploidy; Biopsy; Carcinoma, Squamous Cell; Cell Division; Cell Movement; Cell Transformation, Neoplastic; Demecolcine; Diploidy; Ear Neoplasms; Humans; Karyotyping; Lymphoma; Mitosis; Nose Neoplasms; Pharyngeal Neoplasms