An in vitro cytotoxicity of glufosfamide in HepG2 cells relative to its nonconjugated counterpart

Background Glufosfamide (β-d-glucosylisophosphoramide mustard, GLU) is an alkylating cytotoxic agent in which ifosforamide mustard (IPM) is glycosidically linked to the β-d-glucose molecule. GLU exerted its cytotoxic effect as a targeted chemotherapy. Although, its cytotoxic efficacy in a number of cell lines, there were no experimental or clinical data available on the oncolytic effect of oxazaphosphorine drugs in hepatocellular carcinoma. Therefore, the main objective of the current study is to assess the cytotoxic potential of GLU for the first time in the hepatocellular carcinoma HepG2 cell line model. Methods Cytotoxicity was assayed by the MTT method, and half-maximal inhibitory concentration (IC50) was calculated. Flow cytometric analysis of apoptosis frequencies was measured by using Annexin V/PI double stain, an immunocytochemical assay of caspase-9, visualization of caspase-3, and Bcl2 gene expression were undertaken as apoptotic markers. Mitochondrial membrane potential was measured using the potentiometric dye; JC-1, as a clue for early apoptosis as well as ATP production, was measured by the luciferase-chemiluminescence assay. Results Glufosfamide induced cytotoxicity in HepG2 cells in a concentration- and time-dependent manner. The IC50 values for glufosfamide were significantly lower compared to ifosfamide. The frequency of apoptosis was much higher for glufosfamide than that of ifosfamide. The contents of caspase-9 and caspase-3 were elevated following exposure to GLU more than IFO. The anti-apoptotic Bcl2 gene expression, the mitochondrial membrane potential, and the cellular ATP levels were significantly decreased than in case of ifosfamide. Conclusions The current study reported for the first time cytotoxicity activity of glufosfamide in HepG2 cells in vitro. The obtained results confirmed the higher oncolytic activity of glufosfamide than its aglycone ifosfamide. The generated data warrants further elucidations by in vivo study.

Synergistic Effect of the Long-Term Overexpression of Bcl-2 and BDNF Lentiviral in Cell Protecting against Death and Generating TH Positive and CHAT Positive Cells from MSC

Mesenchymal stem cells (MSC) are potentially a good material for transplantation in many diseases, including neurodegenerative diseases. The main problem with using them is the low percentage of surviving cells after the transplant procedure and the naturally poor ability of MSC to spontaneously differentiate into certain types of cells, which results in their poor integration with the host cells. The aim and the novelty of this work consists in the synergistic overexpression of two genes, BCL2 and BDNF, using lentiviral vectors. According to our hypothesis, the overexpression of the BCL2 gene is aimed at increasing the resistance of cells to stressors and toxic factors. In turn, the overexpression of the BDNF gene is suspected to direct the MSC into the neural differentiation pathway. As a result, it was shown that the overexpression of both genes and the overproduction of proteins is permanent and persists for at least 60 days. The synergistically transduced MSC were significantly more resistant to the action of staurosporine; 12 days after transduction, the synergistically transduced MSC had a six-times greater survival rate. The overexpression of the Bcl-2 and BDNF proteins was sufficient to stimulate a significant overexpression of the CHAT gene, and under specific conditions, the TH, TPH1, and SYP genes were also overexpressed. Modified MSC are able to differentiate into cholinergic and dopaminergic neurons, and the release of acetylcholine and dopamine may indicate their functionality.

Impact of Adenosine A2 Receptor Ligands on BCL2 Expression in Skeletal Muscle Cells

Background: Adenosine plays the role of regulating cell differentiation, proliferation, and apoptosis in various kinds of cells through the B-cell lymphoma 2 (BCL2) pathway. Objectives: Since anti-apoptotic (BCL2) expression plays a role in controlling apoptosis in some cell lines, this study was designed to investigate whether adenosine analogue, NECA (non-selective adenosine receptors agonist), selective adenosine A2B receptor antagonist, PSB 603, and a selective adenosine A2A receptor agonist, CG21680, affect BCL2-gene expression in the skeletal muscle cells of rats. The purpose of this investigation was to test the hypothesis that CG21680 treatment would significantly intensify BCL2 gene expression in rat skeletal muscle. Methods: Flasks measuring 25 cm2 were employed in culturing the rat L6 skeletal muscle cells. After treating these differential cells, the relative mRNA expression level for the BCL2 gene, at varying conditions of treatment, was measured using quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Results: From the qRT-PCR analysis results, it was concluded that BCL2 expression was markedly amplified after selective adenosine A2A receptor agonist, CGS21680 (p < 0.01) treatment. More prospective validation for the adenosine receptors’ contribution in modulating apoptosis by NECA was delivered by the outcomes from the combined pre-treatment of the cells with NECA and PSB 603. These outcomes show that when starved skeletal muscle cells are treated with a combination of NECA and 100 nM PSB 603, there was a substantial decrease in comparison to either treatment used on its own. Conclusions: This study’s results showed, for the first time, an increase in BCL2 gene expression within skeletal muscle after CGS21680 treatment. Hence, the prospective escalation in BCL2 protein expression might have a protective role to play against apoptosis and avert damage to the skeletal muscle.

Oxidative lesions modulate G-quadruplex stability and structure in the human BCL2 promoter

Misregulation of BCL2 expression has been observed with many diseases and is associated with cellular exposure to reactive oxygen species. A region upstream of the P1 promoter in the human BCL2 gene plays a major role in regulating transcription. This G/C-rich region is highly polymorphic and capable of forming G-quadruplex structures. Herein we report that an oxidative event simulated with an 8-oxo-7,8-dihydroguanine (oxoG) substitution within a long G-tract results in a reduction of structural polymorphism. Surprisingly, oxoG within a 25-nt construct boosts thermal stability of the resulting G-quadruplex. This is achieved by distinct hydrogen bonding properties of oxoG, which facilitate formation of an antiparallel basket-type G-quadruplex with a three G-quartet core and a G·oxoG·C base triad. While oxoG has previously been considered detrimental for G-quadruplex formation, its stabilizing effect within a promoter described in this study suggests a potential novel regulatory role of oxidative stress in general and specifically in BCL2 gene transcription.

The genes CNV and expression as a factors of HT-29 cells radioresistance.

e15590 Background: The initial radioresistance of tumor cells associated with certain molecular genetic features has a great influence on the effectiveness of radiation therapy (RD). These features include the transcriptional activity of genes that regulate DNA repair, cell cycle and apoptosis, and their copy number variation (CNV). The aim of the study was to analyze the expression and CNV of genes that regulate DNA repair, cell cycle and apoptosis in HT-29 cells subjected to RD. Methods: HT-29 cell culture was used in the study. For the model experiment, doses of 5 and 7 Gy were used (irradiation was performed 5 times every 24 hours on a Novalis TX linear accelerator). Cell counting was carried out in Goryaev chamber (0.4% trypan blue solution). On the 5th day of irradiation, HT-29 was removed from the substrate with Trypsin / Versen solution. RNA was isolated according to the method of Chomczynski&Sacchi. For cDNA synthesis was used a "REVERTA-L". reagent. The phenol-chloroform method was used to DNA isolate. The RT-qPCR method was used to determine the CNV and expression of 32 genes: AKT, ATM, BRIP, BRCA1, BRCA2, CDK1, CDKN1B, CCND1, CCND3, EXO1, FGFR2, HIST1, H2AX, KU70, PTEN, RAD50, RAP80, RIF1, RNF8 TOPB1, TP53, XRCC4, BAX, CASP8, CASP3, CASP9, MDM2, BCL2, RBBP8, EP300, LIG4, C-FLIP. Statistical analysis was performed using ANOVA and Spearman's rank correlation coefficient (r). Results: After irradiation, only a specific pool of HT-29 cells remained viable: 32% for 5 Gy and 20% for 7 Gy of the initial number of cells. In HT-29 cells irradiated with 7 Gy, the CNV of the BRCA2, H2AX, CASP9 and RBBP8 genes was increased (p < 0.05) and the CNV of BCL2 gene was reduced (p < 0.05) relative to intact cells. In cells irradiated with 5 Gy only CASP9 and RBBP8 CNV was statistically significantly (p < 0.05) increased. In cells irradiated with 5 and 7 Gy, expression of BRCA2, H2AX, CASP9 and RBBP8 genes was statistically significantly (p < 0.05) increased and the expression of the BCL2 gene was reduced relative to intact cells. A strong positive correlation was observed between CNV and expression of the studied genes: r = 0.998 for control, r = 0.989 for cells irradiated at 5 Gy, and r = 0.993 for cells irradiated at 7 Gy. Conclusions: The study showed that 5 day RD at 5 and 7 Gy leads to selective survival of 32% and 20% of cells, respectively, with increased CNV and expression of BRCA2, H2AX, RBBP8 CASP9 genes and reduced CNV and expression of BCL2 gene.