Репозиторий Университета

© 2019 Wiley Periodicals, Inc. To date, a myriad of strategies has been suggested for targeting the chemical signaling of cancer cells. Also, biomechanical features are gaining much more attention. These features can be used as biomarkers which influence cancer progression. Current approaches on cancer treatment are mainly focused on changing the biochemical signaling of cancer cells, whereas less attention was devoted to their biomechanical properties. Herein, we propose targeting of cancer cell mechanics through the microenvironmental mechanical and chemical cues. As such, we examined the role of substrate stiffness as well as the effect of epidermal growth factor receptor (EGFR) blockade in the cell mechanics. As a mechanical stimulus, stiff and soft polydimethylsiloxane substrates were utilized, while as a chemical stimulus, EGFR blockade was considered. Thus, breast cancer cell lines, MCF7 and MDA-MB-231, were cultured among chemical and mechanical groups. The local elasticity of cancer cells was assessed by atomic force microscopy nanoindentation method. Furthermore, we evaluated the effect of mentioned mechanical and chemical treatments on the morphology, actin cytoskeleton structures, and cancer cell migration abilities. The stiffness and migration ability of cancer cells increased by substrate stiffening while Cetuximab treatment demonstrated an elevation in the elastic modulus of cells followed by a reduction in the migration ability. These findings indicate that cancer cell mechanics is modulated not only by the mechanical cues but also by the chemical ones through EGFR signaling pathway. Overall, our results illustrate that manipulation of cell mechanics allows for the possible modulation of tumor cell migration. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 1569–1581, 2019.

© 2018 Vitebsk State Medical University. All rights reserved. Objective: To study the functional activity and cytoarchitectonics of neutrophilic granulocytes by the atomic force microscopy technique in the patients with mechanical jaundice of benign genesis of varying severity. Methods: The subject of the study were 92 patients aged from 47 to 69 years undergoing the in-patient treatment in the surgical departments of medical institutions in Krasnoyarsk with the diagnosis of mechanical jaundice of benign genesis. The control group consisted of 60 donors, comparable in sex and age with the main group. Depending on the severity of mechanical jaundice, luminol-dependent chemiluminescence of neutrophils was investigated and atomic-force microscopy of neurophilic granulocytes was performed to determine the shape, membrane state, geometric dimensions and adhesion forces of the blood neutrophils. Results: In patients with mechanical jaundice, the intensity of spontaneous chemiluminescence depends on the severity of mechanical jaundice. The kinetics of the chemiluminescent response of the peripheral blood neutrophils indicates an increase in the compensatory functional capacity of this cell population in case of mild degree of mechanical jaundice severity with their depletion in parallel with the increase in the severity of mechanical jaundice. Atomic force microscopy revealed violations of the structural organization of the neutrophil granulocyte. With increasing severity of mechanical jaundice, neutrophil became convex in shape, the number of segments of the nucleus increased, the cell membrane became irregular, the neutrophil volume reached 62.20 + 5.94 m3. The magnitude of the adhesion forces of neutrophils decreased by 25% in patients with class B severity of mechanical jaundice and by 31% with class C severity of mechanical jaundice. Conclusions: Based on the analysis of the chemiluminescent activity of neutrophilic granulocytes and their cytoarchitectonics, we concluded that the functional capabilities of neutrophilic granulocytes in mechanical jaundice are depleted in parallel with the increase in the severity of mechanical jaundice. Dysfunctions of neutrophils in mechanical jaundice are caused by the change in its cytoarchitectonics and by the decrease in adhesion forces.

The goal of this study was to find genes that encode cytoskeletal proteins that are potential candidates for the role of triggers in cell mechanosensitivity in the fruit fly. Centrifugation was used to simulate the hypergravity effects (2g group); the constantly changing orientation of the larvae in the gravity field was performed in order to simulate the effects of microgravity (0g group) for 1.5, 6, 12 and 24 h. mRNA levels of different genes that encode the components of both tubulin and actin cytoskeleton were assessed by qRT-PCR. In the 0g group the mRNA levels of beta-tubulin and Msps were reduced after 1.5 h of the exposure and remained unchanged until 12 h, while they exceeded the control level after 24 h. The mRNA level of chaperonin containing T-complex 1 polypeptide subunits recovered earlier: after 6 and 12 h of the microgravity exposure. At the same time, the hypergravity effect led to more significant changes in the mRNA level of TCP1 complex components compared with those of tubulin and Msps. The mRNA level of beta-actin isoforms under micro- and hypergravity was decreased up to 12 h of the exposure, however, it remained reduced under microgravity conditions, while it recovered (Act87E) and even exceeded (Act57B) the reference level under hypergravity conditions. The mRNA level of supervillin was almost unchanged. Under microgravity conditions the mRNA level of fimbrin was decreased (it recovered by the 24 h time point), while the mRNA level of alpha-actinin was significantly increased by the 12 h time point of the exposure and after 24 h it was reduced to the control level. In contrast, under hypergravity conditions the mRNA level of fimbrin initially increased, and after 24 h it dropped below the control, while the mRNA level of alpha-actinin was significantly reduced, and after 24 h it was higher than the reference level. Similar results were obtained earlier in the experiments in rodents, but similar dynamics were observed for alpha-actinin isoforms 1 and 4, although no changes were observed for fimbrin. Since Drosophila melanogaster has no alpha-actinin isoform 4, it is hypothesized that its role in the cell is played by fimbrin.

Цель работы - оценка состояния кортикального цитоскелета волокон камбаловидной мышцы крысы в результате 6-часового антиортостатического вывешивания на фоне предшествующего, в течение 3 сут по 100 мкг/сут, введения смеси фосфатидилхолинов (лецитина). Данные о периметре волокон, толщине подмембранного цитоскелета и доле разрывов в нем относительно периметра получали, используя иммуногистохимическую окраску на альфа-актинин-4. Периметр волокон оставался неизменным во всех группах исследования. При этом доля разрывов была выше в группах вывешивания, чем в соответствующих контрольных группах. Толщина окрашенного слоя, соответствующего подмембранному цитоскелету, не менялась в контрольных группах и в группе вывешивания без лецитина, однако в группе вывешивания на фоне лецитина она достоверно увеличивалась по сравнению с соответствующей контрольной группой на 27 % (p < 0,05) соответственно.

Purpose of the work was to assess the cortical cytoskeleton of m. soleus fibers from rats after 6-hr tail-suspension preceded by 3 days of phosphatidylcholine (lecithin) injections at a dose of 100 µг/d. Data about the fiber perimeter, submembrane cytoskeleton thickness and percentage of bonds breaks along the perimeter were obtained using the alpha-actinin-4 anti-body stain. The fiber perimeter remained unchanged in all groups under study. However, the percentage of breaks was high in suspension groups but not in respective groups of control. Thickness of the stained layer commensurate to the submembrane cytoskeleton did not change in the control groups and in the suspension group without lecithin injections but increased reliably in the suspension group that recieved injections by 27 % (p < 0.05) in comparison with its control.

The goal of this study was to find genes that encode cytoskeletal proteins that are potential candidates for the role of triggers in cell mechanosensitivity in the fruit fly. Centrifugation was used to simulate the hypergravity effects (2g group); the constantly changing orientation of the larvae in the gravity field was performed in order to simulate the effects of microgravity (0g group) for 1.5, 6, 12 and 24 h. mRNA levels of different genes that encode the components of both tubulin and actin cytoskeleton were assessed by qRT-PCR. In the 0g group the mRNA levels of beta-tubulin and Msps were reduced after 1.5 h of the exposure and remained unchanged until 12 h, while they exceeded the control level after 24 h. The mRNA level of chaperonin containing T-complex 1 polypeptide subunits recovered earlier: after 6 and 12 h of the microgravity exposure. At the same time, the hypergravity effect led to more significant changes in the mRNA level of TCP1 complex components compared with those of tubulin and Msps. The mRNA level of beta-actin isoforms under micro- and hypergravity was decreased up to 12 h of the exposure, however, it remained reduced under microgravity conditions, while it recovered (Act87E) and even exceeded (Act57B) the reference level under hypergravity conditions. The mRNA level of supervillin was almost unchanged. Under microgravity conditions the mRNA level of fimbrin was decreased (it recovered by the 24 h time point), while the mRNA level of alpha-actinin was significantly increased by the 12 h time point of the exposure and after 24 h it was reduced to the control level. In contrast, under hypergravity conditions the mRNA level of fimbrin initially increased, and after 24 h it dropped below the control, while the mRNA level of alpha-actinin was significantly reduced, and after 24 h it was higher than the reference level. Similar results were obtained earlier in the experiments in rodents, but similar dynamics were observed for alpha-actinin isoforms 1 and 4, although no changes were observed for fimbrin. Since Drosophila melanogaster has no alpha-actinin isoform 4, it is hypothesized that its role in the cell is played by fimbrin.

Цель работы - оценка состояния кортикального цитоскелета волокон камбаловидной мышцы крысы в результате 6-часового антиортостатического вывешивания на фоне предшествующего, в течение 3 сут по 100 мкг/сут, введения смеси фосфатидилхолинов (лецитина). Данные о периметре волокон, толщине подмембранного цитоскелета и доле разрывов в нем относительно периметра получали, используя иммуногистохимическую окраску на альфа-актинин-4. Периметр волокон оставался неизменным во всех группах исследования. При этом доля разрывов была выше в группах вывешивания, чем в соответствующих контрольных группах. Толщина окрашенного слоя, соответствующего подмембранному цитоскелету, не менялась в контрольных группах и в группе вывешивания без лецитина, однако в группе вывешивания на фоне лецитина она достоверно увеличивалась по сравнению с соответствующей контрольной группой на 27 % (p < 0,05) соответственно.

Purpose of the work was to assess the cortical cytoskeleton of m. soleus fibers from rats after 6-hr tail-suspension preceded by 3 days of phosphatidylcholine (lecithin) injections at a dose of 100 µг/d. Data about the fiber perimeter, submembrane cytoskeleton thickness and percentage of bonds breaks along the perimeter were obtained using the alpha-actinin-4 anti-body stain. The fiber perimeter remained unchanged in all groups under study. However, the percentage of breaks was high in suspension groups but not in respective groups of control. Thickness of the stained layer commensurate to the submembrane cytoskeleton did not change in the control groups and in the suspension group without lecithin injections but increased reliably in the suspension group that recieved injections by 27 % (p < 0.05) in comparison with its control.