P13.23 Study of migration characteristics of human glioma cells in vitro

BACKGROUND

Gliomas are still one of the most aggressive human cancers, and even despite modern therapeutic approaches, the prognosis for patients with this disease is not favorable. It is known that glioma cells are capable of local invasiveness, when glioma cells migrate into healthy brain tissue. A lack of any definite markers, characterizing migrating glioma cells and allowing them to be distinguished from healthy brain cells, requires a thorough investigation. In case it would be possible to characterize invasive glioma cells, then a development of targeted therapy could be feasible.

MATERIAL AND METHODS

Cell cultures of human gliomas Gr II, III and IV were developed with 5 cultures for each Grade. MTT, RT-PCR, Western and Nosern blot, transcriptome analysis were applied.

RESULTS

Three cultures of human gliomas had a high degree of migration, within the range of 6% - 14%. These cultures were developed from gliomas of Grade III and Grade IV, and with IDH1- (minus) phenotype. Moreover, cell cultures with IDH1 + (plus) phenotype had a low migration rate within 1%. An intensity of migration correlated with the degree of malignancy, and an average rate decreased with a decrease of the Grade. Moreover, an analysis of the proliferative activity of cell cultures of human gliomas of various degrees of malignancy did not reveal a relationship with a migratory properties of cultures. A number of actively proliferating cultures did not show high migration, while cultures with medium proliferative activity could show a high level of migration. The low level of proliferation of cultures of gliomas of Grade II and I at the beginning of cultivation, in some cases, subsequently increased, but an inherent low migration activity did not change. In actively migrating cultures, a significant decrease in the expression of Sox2 and Nestin is detected. A positive correlation was found between migration abilities of human glioma cell culture cells and the marker Ki67, GFAP, Sox2, and Oct4. The difference was statistically significant by the one-sided Mann-Whitney test.

CONCLUSION

Conclusions: Cell cultures derived from glioma tumor tissue can be used to predict invasive properties of the tumor. High tumor invasiveness is characteristic for Grade III and Grade IV, and with IDH1- (minus) phenotype, and it also correlates with elevated expression of GFAP, Sox2 and Oct4The reported study was funded by RFBR according to the research project № 18-29-01012 and by the Ministry of Science and Higher Education of the Russian Federation, grant number 075-15-2020-809 (13.1902.21.0030).

P04.19 A combined use of a G-quadruplex oligonucleotide (GQ) and neuro-inducing small molecules inhibit glioblastoma cell proliferation

BACKGROUND

According to one of the theories, gliomas can occur as a result of dysregulation of stem cell division in the subventricular region of the brain. The CD133 membrane marker is a characteristic of both normal and tumor neural stem cells therefore it can be used to isolate a stem cell population from tumor tissue. Tumor cells actively proliferate which suggests that their possible differentiation may be achieved by inhibiting of their division as these two processes are mutually exclusive. For this purpose, G-quadruplex oligonucleotides together with neural-inducers such as a brain-derived neurotrophic factor (BDNF) may be used.

MATERIAL AND METHODS

Five cell cultures obtained from human glioblastoma tissues were analyzed for expression of CD133 using RT-qPCR. From cell culture with the highest level of CD133 using immunomagnetic separation CD133+ and CD133- cultures were received. CD133fr/peGFP-c1 recombinant DNA consisted of a CD133 second extracellular loop fragment and a peGFP-c1 vector was constructed to determine the localization of prominin-1, that is known as CD133 when found on cell membrane, using confocal microscopy. On chosen cell cultures an oligonucleotide bi-(AID-1-T) and its combination with BDNF were tested. The mechanism of GQ’s action is cytostatic and its non-toxicity properties were proved by flow cytometry. For evaluating the proliferative activity of cells MTT assay was performed on 10th and 20th days after exposure to the factors.

RESULTS

Cell culture G01 was chosen for further research as it had the highest level of the CD133. Colocalization of CD133 and GFP demonstrated a membrane localization of CD133 in cells with high expression level of this marker. MTT assay on 10th day after exposure to bi-(AID-1-T) as well as its combination with BDNF on cell culture G01 CD133- showed total inhibition of cell proliferation. The same combinations tested on G01 CD133+ cell culture demonstrated no difference in proliferative activity. After 20 days after exposure to bi-(AID-1-T) and combination of bi-(AID-1-T) with BDNF the significant decrease of G01 CD133+ cells’ proliferation was observed. When tested on whole glioblastoma cell culture G01 these combinations also showed significant inhibition of cell proliferation.

CONCLUSION

We showed that glioblastoma cells upon transfection with recombinant DNA, that contains a fragment of CD133, mainly have a membrane localization of this marker. It was observed that CD133+ cells are more stable to external influence that can be a proof of the fact that CD133 is charactered for glioblastoma stem cells. We tested the effect of an GQ bi-(AID-1-T) and its combination with BDNF and showed that BDNF is necessary for blocking proliferation of glioblastoma cells. Altogether, the results may be used for further research as it reveals a potential treatment for patients with glioblastoma.

Grant №075-15-2020-809 (13.1902.21.0030).

Effects of striatal transplantation of cells transfected with GDNF gene without pre- and pro-regions in mouse model of Parkinson's disease

Background

Previously, we have shown that transgenic cells bearing the GDNF gene with deleted pre- and pro-regions (mGDNF) can release transgenic GDNF. The medium conditioned by transgenic cells with mGDNF induced axonal growth in rat embryonic spinal ganglion in vitro. Here we demonstrate a neurotrophic effect of mGDNF on PC12 cells in vitro as well as its neuroprotective effect on dopaminergic neurons in the substantia nigra pars compacta in vivo as indicated by improved motor coordination and sleep-wakefulness cycle in the MPTP mouse model of Parkinson’s disease.

Results

HEK293 cells were transfected with a vector encoding an isoform of the human GDNF gene with deleted pre- and pro-regions (mGDNF). This factor in the medium conditioned by the transfected cells was shown to induce axonal growth in PC12 cells. The early Parkinson’s disease model was established by injection of the dopaminergic pro-neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) into C57Bl/6 mice. Transgenic HEK293/mGDNF/GFP cells were transplanted into the striatum (caudate-putamen) of experimental mice. The sleep-wakefulness cycle was studied by continuous EEG and motor activity monitoring 1 and 2 weeks after MPTP injection. After the experiment, the motor coordination of experimental animals was evaluated in the rotarod test, and dopaminergic neurons in the substantia nigra pars compacta were counted in cross-sections of the midbrain. MPTP administration lowered the number of tyrosine hydroxylase immunopositive cells in the substantia nigra pars compacta, decreased motor coordination, and increased the total wake time during the dark period. The transplantation of HEK293/mGDNF cells into the caudate-putamen 3 days prior to MPTP injection smoothed these effects, while the control transplantation of HEK293 cells showed no notable impact.

Conclusions

Transplantation of transgenic cells with the GDNF gene lacking the pre- and pro-sequences can protect dopaminergic neurons in the mouse midbrain from the subsequent administration of the pro-neurotoxin MPTP, which is confirmed by polysomnographic, behavioral and histochemical data. Hence it is released from transfected cells and preserves the differentiation activity and neuroprotective properties.

In vitro neuronal induction of adipose-derived stem cells and their fate after transplantation into injured mouse brain

The effect of substances known as inducers of neuronal differentiation on cultured human and mouse adipose-derived mesenchymal stem cells (ASCs) and their fate after transplantation into the injured and ischemic mouse brains were studied. ASCs were isolated from the human and mouse adipose tissue. Inducers of neuronal differentiation included β-mercaptoethanol, glial cell line-derived neurotrophic factor (GNDF), brain-derived neurotrophic factor (BDNF), retinoic acid (RA), 5-azacytidine, as well as their combinations. Three days after the induction, the phenotype of the induced cells was analyzed using immunocytochemistry and real-time PCR assay for differential expression of specific genes. The induction efficiency was evaluated by the increased transcription of neuronal differentiation markers: nestin, β-III-tubulin (Tub-B), microtubule-associated protein 2 (MAP2), and neuron-specific enolase (ENO2). The expression of marker genes was tested by immunocytochemical analysis. ASC cultivation in the medium with RA or BDNF in combination with 5- azacytidine for a week increased the mRNA and protein levels of nestin, Tub-B, and ENO2. The transplantation of induced mouse ASCs into the mouse brain increased the lifespan of the cells relative to control uninduced cells and promoted their migration from the transplantation site to the recipient cerebral parenchyma. The transplantation of the induced cells into the mouse brain pre-exposed to endothelin- 1 promoted a more active cell migration into the surrounding ischemic brain tissue. Thus, ASC exposure to RA or BDNF in combination with 5-azacytidine elevated the transcription of the neuronal differentiation markers and improved the viability and integration of ASCs grafted into the mouse brain.

3-D Golgi and image analysis of the olfactory tubercle in schizophrenia

OBJECTIVE

To examine morphologic changes in the olfactory tubercle (OT) spiny neurons and astrocytes in schizophrenia (Sch) by means of quantitative 3-D Golgi and immunocytochemical studies.

STUDY DESIGN

Free-floating vibrotome sections of postmortem brain tissue from 10 controls and 12 Sch cases were used for Golgi study and glial fibrillary acidic protein (GFAP) immunocytochemistry. A gray level image analysis was applied for quantitative estimation of GFAP-positive astrocytes on uniform, randomly sampled sections. This method is effective for low-contrast objects on an uneven background. Golgi-impregnated OT spiny neurons were analyzed both qualitatively and quantitatively in three dimensions with a semiautomated microscope-computer system. From digitized image of the neurons, various metric parameters were estimated to characterize the dendritic tree.

RESULTS

In cases of Sch, degenerative changes in the dendrites of OT spiny neurons were revealed. A decrease in the maximal radius of the dendritic tree and total length of dendrites were accompanied by an increase in the length density of dendrites. Hypertrophy and a more-intensive GFAP reaction of astrocytes were found in OT of Sch.

CONCLUSION

Based on these results, one can hypothesize that OT spiny neurons in Sch are involved in the process of dendritic reorganization, including degenerative changes in dendrites.