Novel nucleolar and nuclear morphology in a vincristine-dependent human leukemia cell line (L100)

Comparative multiparametric analysis of HeLa and RD cell culture reactions to solcoseryl

Reactions of continuous HeLa and RD cell cultures and their nuclear and nucleolar apparatus to addition of solcoseryl into the medium were studied. The monolayer density, proliferation activity, percentage of dead cells, RNA and DNA content in the nuclei and nucleoli, number of nucleoli in the nuclei, cell distribution in the population by the number of nucleoli in the nuclei, volume and complete surface area of the nuclei and nucleoli, and the nucleolar/nuclear ratio were evaluated. The cultures differently reacted to solcoseryl in the medium at the population and cellular levels of their organization. By the results of multiparametric analysis of the reactions of cells and their nuclear and nucleolar apparatus, solcoseryl can be referred to bioactive substances with characteristics of a factor regulating cell population growth.

Pharmacoproteomic approach to the study of drug mode of action, toxicity, and resistance: applications in diabetes and cancer

Proteomics is a powerful technique for investigating protein expression profiles in biological systems and their modifications in response to stimuli or to particular physiological or pathophysiological conditions. It is therefore a technique of choice for the study of drug mode of action, side-effects, toxicity and resistance. It is also a valuable approach for the discovery of new drug targets. All these proteomic applications to pharmacological issues may be called pharmacoproteomics. The pharmacoproteomic approach could be particularly useful for the identification of molecular alterations implicated in type 2 diabetes and for further characterization of existing or new drugs. In oncology, proteomics is widely used for the identification of tumour-specific protein markers, and pharmacoproteomics is used for the evaluation of chemotherapy, particularly for the characterization of drug-resistance mechanisms. The large amount of data generated by pharmacoproteomic screening requires the use of bioinformatic tools to insure a pertinent interpretation. Herein, we review the applications of pharmacoproteomics to the study of type 2 diabetes and to chemoresistance in different types of cancer and the current state of this technology in these pathologies. We also suggest a number of bioinformatic solutions for proteomic data management.

Ultrastructural, cytochemical, and immunocytochemical study of nuclei and cytoskeleton of thyroid papillary carcinoma cells

One of the most constant and typical histological markers of thyroid papillary carcinoma is the presence of multilobated and ground-glass nuclei. With the intention of extending and characterizing the ultrastructural comprehension of this feature, thyroid papillary carcinoma cells and normal follicular cells were studied using chromatin and ribonucleoprotein preferential staining techniques, as well as immunolabeling with antibodies against DNA, lamins, vimentin, and desmin. Carcinoma cells showed scant compact chromatin arranged in small masses. A special type of nuclear bodies with DNA immunoreactive fibrils was found in these cells. Some nucleoli were surrounded by a double fibrillar layer limiting a perinucleolar space occupied by RNP fibrogranular structures that differed from those of normal nuclei. Perichromatin granules were scarce compared to normal follicular cells. Immunoelectron microscopic studies of lamins showed diminished immunoreactivity in the nuclei of carcinoma cells. A perinuclear distribution of desmin and vimentin filament was found in tumor cells. The cytoplasm of normal follicular cells showed scarce immunoreactivity to vimentin and no immunolabeling for desmin. Both types of filaments attach to the nuclear pore complex and to other regions of the nuclear envelope. Contacts between labeled filaments and desmosomes or hemidesmosomes were frequent. The results show that in papillary thyroid carcinoma cells, changes in the distribution of chromatin and ribonucleoproteins, either alone or in conjunction with scarce lamin immunolabeling and perinuclear vimentin and desmin filamentous rings, may be responsible for the characteristic ground glass and multilobated nuclei.

Microtubule-dependent multilobular organization of the nucleus in sensitive and multidrug-resistant L0 leukemia cells

The relationship between the nuclear morphology and the microtubular organization of L100 and L1000 cells, two vincristine-induced multidrug resistant human acute lymphocytic leukemia cell lines, was examined and compared to that of L0 parental cells. The L0 parental cells contained a round nucleus and the microtubules were evenly distributed throughout the cytoplasm. In contrast, the microtubules of the L100 and L1000 cells were localized between the lobular structures of a multilobulated nucleus. Disassembly of microtubules in L100 and L1000 cells by colchicine resulted in the loss of the multilobulated morphology of the nucleus. While the total cellular content of tubulin of L0 and L100 cells was similar, the content of microtubules of L100 cells was only 55% of that observed in L0 cells. Two, 28 kDa (pI 6.9) and 31 kDa (pI 4.4), microtubule-associated proteins were found to be overexpressed in L100 and L1000 cells. The results indicate that the multilobulated nuclear morphology of L100 and L1000 cells is dependent upon the unique and intact organization of the microtubules; the distinct organization of the microtubules and the multilobular nuclear morphology of the two resistant cell lines may be due to the differential expression of specific microtubule-associated proteins.

Collateral sensitivity to radiation and cis-platinum in a multidrug-resistant human leukemia cell line

Although collateral sensitivity to gamma radiation has previously been described in multidrug-resistant tumor cell lines, we describe here a multidrug-resistant human T-cell acute lymphatic leukemia cell line, L100, which displayed increased sensitivity to both gamma radiation and cis-platinum. Cis-platinum cytotoxicity of parental L0 cells and L100 cells was enhanced, whereas radiation sensitivity of L0 and L100 cells was unaltered by glutathione depletion. These results indicate that disparate mechanisms are operative in the collateral sensitivity of L100 cells to gamma radiation and cis-platinum.