Mechanical Properties and Nanomotion of BT-20 and ZR-75 Breast Cancer Cells Studied by Atomic Force Microscopy and Optical Nanomotion Detection Method.

Cells of two molecular genetic types of breast cancer-hormone-dependent breast cancer (ZR-75 cell line) and triple-negative breast cancer (BT-20 cell line)-were studied using atomic force microscopy and an optical nanomotion detection method. Using the Peak Force QNM and Force Volume AFM modes, we revealed the unique patterns of the dependence of Young's modulus on the indentation depth for two cancer cell lines that correlate with the features of the spatial organization of the actin cytoskeleton. Within a 200-300 nm layer just under the cell membrane, BT-20 cells are stiffer than ZR-75 cells, whereas in deeper cell regions, Young's modulus of ZR-75 cells exceeds that of BT-20 cells. Two cancer cell lines also displayed a difference in cell nanomotion dynamics upon exposure to cytochalasin D, a potent actin polymerization inhibitor. The drug strongly modified the nanomotion pattern of BT-20 cells, whereas it had almost no effect on the ZR-75 cells. We are confident that nanomotion monitoring and measurement of the stiffness of cancer cells at various indentation depths deserve further studies to obtain effective predictive parameters for use in clinical practice

Internuclear chromosome bridges in thyrocytes of papillary thyroid cancer in patients, subjected to radioactive iodine isotopes during first months after the accident at the Chernobyl nuclear power plant

Background. Fallout from Chernobyl accident was primarily to iodine radioisotopes, with Iodine-131 (I-131) being the most predominant. Radioiodines accumulated following the accident could induce pathologic changes in thyrocytes. Internuclear chromatine bridges and ‘‘tailed’’nuclei - broken bridge fragments - are considered like cytopathological effects of radiation exposure as these abnormalities are formed from dicentric chromosomes, which are established markers of radiation exposure. Objective. To test the possibility that internuclear bridges and tailed nuclei are cytological markers of radiation exposure of the thyroid. Methods. We investigated thyrocyte nuclear abnormalities in cytological samples from fine-needle aspiration biopsy in papillary thyroid cancer patients exposed to radioiodine after Chernobyl accident (35 subjects from Gomel region, Belarus) and in papillary thyroid cancer of unexposed patients (25 subjects from Leningrad region, Russia). Nuclear abnormalities included internuclear bridges and ‘‘tailed’’ nuclei were examined. Results. Cells in papillary thyroid cancer of irradiated patients are characterized by the high frequency of appearance of hole nucleoplasmic bridges as well as broken bridges in comparison with the control group. The average frequency of thyrocytes with bridges in irradiated patients was almost 4 times higher than that in the unexposed group (4,69±0,69‰ vs. 1,10±0,23 ‰, p<0.001). The same contrast was observed in parameter “frequency of thyrocytes with “tailed” nuclei” (12,40±1,82 ‰ vs 3,68±0,39 ‰, (p<0.001)). Conclusion. Thyrocytes with internuclear bridges may be considered as markers of radiation effects on the thyroid gland. Citation: Kravtsov VIu, Ibragimova NV, Nikonovich SN, Nadyrov EA, Rozhko AV. [Internuclear chromosome bridges in thyrocytes of papillary thyroid cancer in patients, subjected to radioactive iodine isotopes during first months after the accident at the Chernobyl nuclear power plant]. Morphologia. 2015;9(4):37-42. Russian