Identification of differentially regulated deceitful proteins in SH-SY5Y cells engineered with Tet-regulated protein expression system.

Tetracycline regulated protein expression in mammalian cells is a powerful tool to predict the physiological function, cellular localization, and stability of a protein. In addition, to predict metabolic networks affected by the expression of wild-type or mutant forms of proteins, researchers generally produce a single mammalian cell clone that can express the protein of interest under tetracycline control and study the changes occurring in overall proteome before and after expression of a protein of interest. One limitation of tetracycline regulated clonal cell creation, however, is that it sometimes creates clones with changed protein levels even without the expression of the protein of interest due to the nonspecific insertion of the gene encoding the protein of interest into the genome or disruption of a metabolic pathway due to insertional silencing or activation. The aim of this study was to demonstrate the limitation of tetracycline regulated gene expression by creating clonal cell lines expressing the wild-type or the mutant forms of Fat mass and obesity-associated protein. Comparative proteome analysis of the protein extracts by two-dimensional gel electrophoresis coupled to MALDI-TOF/TOF revealed the presence of eight proteins subjected to differential regulation even in the absence of induction. The identified proteins were 14-3-3 protein Epsilon, Vimentin, Heterogeneous nuclear ribonucleoprotein K, Tubulin beta-2C chain, Heat shock protein HSP 90-alpha, Heat shock protein HSP 90-beta, Alpha-enolase, TATA-binding protein-associated factor 2N. An ultimate care should be taken to prevent reporting of deceitful proteins generated from studies utilizing tetracycline regulated gene expression systems.

Effect of resveratrol on chromosomal aberrations induced by doxorubicin in rat bone marrow cells.

This study investigated the effects of resveratrol (RES) on doxorubicin (DXR) induced rat bone marrow cell chromosome aberrations. RES, a polyphenolic compound, has attracted considerable attention because of its antioxidant and antimutagenic effects. DXR, a chemotherapeutic agent, is known to cause chromosomal aberrations in healthy cells in cancer patients. In this study, Wistar albino male rats were divided into 6 groups with 6 animals each. The control group received distilled water i.p. and the DXR group received an i.p. injection of doxorubicin (90mg/kgbw). For the 2 RES dose groups (12.5 and 25mg/kgbw, respectively), RES was injected i.p. 5 times during the 24h study period to coincide with the schedule for the DXR+RES groups. The DXR-RES groups received DXR (90mg/kgbw) and RES at either 12.5 or 25mg/kgbw, i.p. 30min before, concurrently, and then every 6h after DXR administration. Bone marrow collection was timed to coincide with 24h after DXR administration in all groups. RES administration alone did not induce any significant increase in frequency of chromosome aberrations or abnormal metaphases compared with controls (p>0.05) while DXR alone did (p<0.05). In the DXR-RES 12.5mg/kgbw group, frequency of chromosome aberrations and abnormal metaphases were slightly reduced compared to DXR alone, but this was not statistically significant. However, in the DXR-RES 25mg/kgbw group, RES resulted in a statistically significant reduction in the frequency of chromosome aberrations and abnormal metaphases compared to those induced by DXR alone (p<0.05). These results indicate that RES (25mg/kgbw) significantly reduces frequency of DXR induced chromosome damage in bone marrow cells.

Protective effects of increasing vitamin E and a doses on cisplatin-induced oxidative damage to kidney tissue in rats.

OBJECTIVE: Cisplatin (DDP, cis-diamminedichloroplatinium II) is one of the most potent chemotherapeutic antitumor drugs, but is able to generate reactive oxygen species (ROS) and it also inhibits the activity of antioxidant enzymes in renal tissue. In the present study, we investigated the preventive effect of 100, 200 and 400 mg/kg b.w. doses of vitamin E (VE), and 25, 50, and 100 mg/kg b.w. doses of vitamin A (VA) combination on malondialdehyde (MDA), nitric oxide (NO), and glutathione (GSH) levels and superoxide dismutase (SOD) activity in cisplatin-induced toxicity in rat kidneys. Our literature survey indicated a lack of any experimental study showing the beneficial effect of VA on cisplatin-induced MDA, NO, GSH and SOD changes. For this reason, we hoped that this study would provide a unique contribution in that respect. MATERIALS AND METHODS: 59 Wistar rats (11 to replace prematurely lost animals) were used. 48 evaluable rats were divided into 8 groups (n = 6 in each group): control group, DDP alone (5 mg/kg b.w.) group, 3 VE combination treatment groups of VE100+DDP, VE200+DDP, and VE400+DDP, and 3 VA combination treatment groups of VA25+DDP, VA50+DDP, and VA100+DDP. Kidney MDA, GSH, NO levels and SOD activities were determined for the assessment of oxidant-antioxidant balance. RESULTS: While in the DDP group the tissue levels of MDA and NO were found to be significantly higher than in the control group, GSH levels and SOD activities were significantly lower. MDA and NO levels were found to be significantly lower and GSH levels and SOD activities significantly higher in the VE200+DDP and VE400+ DDP groups when compared with the DDP alone group. MDA and NO levels were found to be significantly lower in the VA50+DDP and VA100+DDP groups when compared with the DDP alone group. However, identical comparisons with the DDP alone group showed significantly higher GSH levels and SOD activities in the VA25+DDP, VA50+DDP, and VA100+DDP groups. Among the VE100+ DDP, VE200+DDP, and VE400+DDP groups, and VA25+ DDP, VA50+DDP, and VA100+DDP groups, MDA and NO levels decreased and GSH levels and SOD activities increased steadily and significantly as the doses of VE and VA increased. CONCLUSION: These vitamins would be effective in protecting against cisplatin-induced tissue damage in rat kidneys. It is possible that the toxic effect of cisplatin is somehow minimized by a compensatory mechanism involving VE and VA via induction of antioxidant enzyme activities following intraperitoneal injection of DDP.

Effects of 10alpha,25-dihydroxyvitamin D3 on doxorubicin-induced chromosomal aberrations in rat bone marrow cells.

The present study was carried out to evaluate the effects of 1alpha,25-dihydroxyvitamin D3 (VD) on chromosomal aberrations induced by doxorubicin (DXR). Wistar rats were divided into eight experimental groups of five animals each. Control group animals were treated with i.p. distilled water. The animals in three VD groups were given only VD for 4, 6 or 8 weeks. In the DXR groups the animals were given only DXR. In the combination groups VD doses were given for 4, 6 or 8 weeks for each group and DXR was injected 24 h before sacrificing the rats. DXR (50 mg/100 g b.w.) was injected intraperitoneally and VD by gavage 3 microg/kg/day twice weekly. Animals treated with both VD and DXR showed a low frequency of chromosomal aberrations and abnormal metaphases when compared with animals treated with DXR alone (p < 0.0001). The numbers of both chromosomal aberrations and abnormal metaphases were similar in weeks 6 and 8 (p > 0.05) and lower than those in week 4 for the VD groups (p < 0.0001). Under the present experimental conditions, the efficiency of VD in protecting cells against DXR-induced chromosome damage was found to be dose dependent. The protective effects of VD on chromosome aberrations induced by DXR are discussed in the light of literature data.

Effects of vitamin A on doxorubicin-induced chromosomal aberrations in bone marrow cells of rats.

The present study was carried out to evaluate the role of vitamin A (VA) on the induction of chromosomal aberrations (CA) in rat bone marrow cells and to investigate its modulating effect on chromosomal damage induced by doxorubicin (DXR). Wistar rats were treated with VA (7.5, 15 and 30 microg/kg body wt) once a day for 2 days by gavage before injecting DXR (90 mg/kg body wt). Rats in the control group were treated with corresponding doses of water and olive oil. Animals treated with the medium dose of VA (15 microg/kg body wt) plus single dose of DXR presented a statistically significant reduction in total number of CA and in number of abnormal metaphases (P < 0.05). However, when compared with control and DXR groups, the low and high VA doses (7.5 and 30 microg/kg body wt) were found to be less efficient than the medium dose VA (15 microg/kg body wt) in terms of parameters analyzed. Furthermore, the high dose of VA group (30 microg/kg body wt) was found to be clastogenic (P < 0.05). This study concludes that the protective effect of VA against chromosome damage is dose dependent.