formazans and Esophageal-Neoplasms

Two new complexes [(Etdpa)MnCl(2)] and [(Adpa)Mn(Cl)(H(2)O)] (Etdpa = ethyl bis(2-pyridylmethyl)amino-2-propionate; Adpa = bis(2-pyridylmethyl)amino-2-propionic acid) were synthesized and characterized by spectral methods. The crystal structure of [(Etdpa)MnCl(2)] shows that the Mn(II) atom is coordinated by three N atoms (N1, N2, N3), one oxygen atom (O1) of the ligand (Etdpa) and two chloride atoms (Cl1, Cl2), forming a distorted octahedral geometry. The binding interaction between ct-DNA and the synthesized complexes was relatively weak, but they can inhibit the induced swelling of Ca(2+)-loaded mitochondria in a dose-dependent manner. The [(Adpa)Mn(Cl)(H(2)O)] can cause the obvious decrease of mitochondria membrane potential. The MTT (3-[4,5-Dimethylthiazol-2-yl]-2,5-diphenpyltetra-zolium bromide) assay shows that the two Mn(II) complexes are more active against cancer cells. Especially [(Adpa)Mn(Cl)(H(2)O)] can inhibit the proliferation of glioma cells with IC(50) 9.5 μM. Experimental results indicate that the [(Adpa)Mn(Cl)(H(2)O)] could be a new potential antitumor complex to target the mitochondria.

Topics: Animals; Antineoplastic Agents; Brain Neoplasms; Breast Neoplasms; Cell Line, Tumor; Cell Survival; Coordination Complexes; DNA; Drug Evaluation, Preclinical; Drug Interactions; Esophageal Neoplasms; Female; Formazans; Glioma; HeLa Cells; Humans; Inhibitory Concentration 50; Manganese; Membrane Potential, Mitochondrial; Mitochondria, Liver; Molecular Structure; Oxygen; Rats; Reference Standards; Tetrazolium Salts

Identification of reliable markers of chemo- and radiosensitivity and the key molecules that enhance the susceptibility of squamous esophageal cancer cells to anticancer treatments would be highly desirable. To test whether regenerating gene (REG) I expression enhances chemo- and radiosensitivity in esophageal squamous cell carcinoma cells, we used MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assays to compare the chemo- and radiosensitivities of untransfected TE-5 and TE-9 cells with those of cells stably transfected with REG Ialpha and Ibeta. We then used flow cytometry to determine whether REG I expression alters cell cycle progression. No REG I mRNA or protein were detected in untransfected TE-5 and TE-9 cells. Transfection with REG Ialpha and Ibeta led to strong expression of both REG I mRNA and protein in TE-5 and TE-9 cells, which in turn led to significant increases in both chemo- and radiosensitivity. Cell cycle progression was unaffected by REG I expression. REG I thus appears to enhance the chemo- and radiosensitivity of squamous esophageal cancer cells, which suggests that it may be a useful target for improved and more individualized treatments for patients with esophageal squamous cell carcinoma.

Topics: Antimetabolites, Antineoplastic; Carcinoma, Squamous Cell; Cell Line, Tumor; Cell Proliferation; Dose-Response Relationship, Radiation; Esophageal Neoplasms; Fluorouracil; Formazans; Humans; Lithostathine; Proteins; Radiation Tolerance; RNA, Messenger; Tetrazolium Salts; Transfection

Flavopiridol is a synthetic flavone that has shown an antitumor effect against several cancers. Here, we investigated the in vitro effect of flavopiridol alone and the combined effect of low-dose flavopiridol plus radiation on esophageal squamous cell carcinoma cell lines. Esophageal squamous cell carcinoma cell lines (TE8, TE9 and KE4) were exposed to flavopiridol (0.05-400 nmol/L) for 48 h. Growth inhibition was evaluated by MTT assay, cell cycle distribution was determined by flow cytometry, and cyclin D1, Bcl-2 and Rb protein expression was detected by Western blotting. The effect of 0.05 nmol/L flavopiridol as a radio-sensitizer was determined by clonogenic assay. The IC50 was approximately 110-250 nmol/L. Exposure to 0.05 nmol/L flavopiridol for 48 h increased the G2/M population, while 300 nmol/L increased the G1 population. At a concentration of 300 nmol/L, nuclear fragmentation and chromatin condensation were observed in all three cell lines. Exposure to 300 nmol/L flavopiridol decreased the levels of cyclin D1 and Rb protein in all three cell lines and Bcl-2 protein was also decreased in TE8 and KE4 cells. Moreover, exposure to 0.05 nmol/L flavopiridol slightly decreased the levels of cyclin D1, Rb and Bcl-2 protein in KE4 cells. Flavopiridol treatment (0.05 nmol/L) enhanced the radio-sensitivity in all three cell lines. Low-dose flavopiridol augmented the response of esophageal squamous cell carcinoma cell lines to radiation. Administration of a low dose of flavopiridol could be a potent new therapeutic approach for improving the efficacy of radiotherapy against esophageal cancer.

Topics: Antineoplastic Agents; Apoptosis; Blotting, Western; Carcinoma, Squamous Cell; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Cyclin D1; Esophageal Neoplasms; Flavonoids; Flow Cytometry; Formazans; Genes, bcl-2; Growth Inhibitors; Humans; Piperidines; Radiation Tolerance; Radiation-Sensitizing Agents; Retinoblastoma Protein; Tetrazolium Salts; Treatment Outcome

Our previous study demonstrated that the herbal medicine, Oren-to, had antitumor effects on esophageal cancer cells (ECCs) in vitro. The purpose of this study was to examine which of the seven constituents of Oren-to had antitumor effects on esophageal cancer cells. MTT assay showed that, of the seven constituents, only the aqueous extract of Coptidis Rhizoma had potent inhibitory effect on the proliferation of two types of ECC lines, YES-3 and YES-4. In addition, the proliferation of all six types of ECC lines (YES-1 to YES-6) was inhibited in a dose-dependent manner (P<0.001 for all), when co-cultured at each concentration of Coptidis Rhizoma for 72 h. The ID50 of Coptidis Rhizoma for YES-1 to YES-6 was 2.2 microg/ml, 3.0 microg/ml, 0.25 microg/ml, 2.8 microg/ml, 2.5 microg/ml, and 0.5 microg/ml, respectively, berberine, one of protoberberine components of Coptidis Rhizoma, showed potent antitumor effects on all six types of ECC lines as well as Coptidis Rhizoma. In addition, the ID50 of berberine showed a positive correlation with that of Coptidis Rhizoma in six types of ECC lines examined (r2 = 0.763, P = 0.023). Cell cycle analysis of Coptidis Rhizoma-treated cancer cells showed the accumulation of cells in the G0/G1 phase and relative decrease of the S phase. These results support the possibility that the use of Coptidis Rhizoma containing abundant berberine may be useful as one of alternative therapies for esophageal cancers.

Topics: Antineoplastic Agents; Berberine; Cell Cycle; Cell Division; Coptis chinensis; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Drugs, Chinese Herbal; Esophageal Neoplasms; Flow Cytometry; Formazans; Humans; Tetrazolium Salts; Tumor Cells, Cultured