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Cytotoxic effects and the mechanism of three types of magnetic nanoparticles on human hepatoma BEL-7402 cells.

Kai W, Xiaojun X, Ximing P, Zhenqing H, Qiqing Z - Nanoscale Res Lett (2011)

Bottom Line: The increase in apoptosis was accompanied with the Bax over-expression, mitochondrial membrane potential decrease, and the release of cytochrome C from mitochondria into cytosol.Our results revealed that certain concentrations of the three types of MNPs affect BEL-7402 cells viability via cell arrest and inducing apoptosis, and the MNPs-induced apoptosis is mediated through the mitochondrial-dependent pathway.The influence potency of MNPs observed in all experiments would be: C-Fe > Fe3O4 > OA-Fe3O4.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, PR China. qiq@xmu.edu.cn.

ABSTRACT
The evaluation of the toxicity of magnetic nanoparticles (MNPs) has attracted much attention in recent years. The current study aimed to investigate the cytotoxic effects of Fe3O4, oleic acid-coated Fe3O4 (OA-Fe3O4), and carbon-coated Fe (C-Fe) nanoparticles on human hepatoma BEL-7402 cells and the mechanisms. WST-1 assay demonstrated that the cytotoxicity of three types of MNPs was in a dose-dependent manner. G1 (Fe3O4 and OA-Fe3O4) phase and G2 (C-Fe) phase cell arrests and apoptosis induced by MNPs were detected by flow cytometry analysis. The increase in apoptosis was accompanied with the Bax over-expression, mitochondrial membrane potential decrease, and the release of cytochrome C from mitochondria into cytosol. Moreover, apoptosis was further confirmed by morphological and biochemical hallmarks, such as swollen mitochondria with lysing cristae and caspase-3 activation. Our results revealed that certain concentrations of the three types of MNPs affect BEL-7402 cells viability via cell arrest and inducing apoptosis, and the MNPs-induced apoptosis is mediated through the mitochondrial-dependent pathway. The influence potency of MNPs observed in all experiments would be: C-Fe > Fe3O4 > OA-Fe3O4.

No MeSH data available.


Related in: MedlinePlus

Caspase-3 activity of BEL-7402 cells after incubation with MNPs for 24 h. After BEL-7402 cells were treated with MNPs (0.05 and 1 mg/mL) for 24 h, caspase-3 activity was determined using caspase-3/CPP32 Colorimetric Assay Kit. *P < 0.05 vs. control; **P < 0.01 vs. control.
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Figure 6: Caspase-3 activity of BEL-7402 cells after incubation with MNPs for 24 h. After BEL-7402 cells were treated with MNPs (0.05 and 1 mg/mL) for 24 h, caspase-3 activity was determined using caspase-3/CPP32 Colorimetric Assay Kit. *P < 0.05 vs. control; **P < 0.01 vs. control.

Mentions: Mitochondrial membrane permeability is regulated through a family of proto-oncogenes. Bax is an important pro-apoptotic protein of the Bcl-2 family members [46]. High level of Bax can translocate to the outer mitochondrial membrane (OMM) and insert into the OMM. Then, Bax forms oligomers that are thought to be important in the formation of the mitochondrial permeability transition pore (PTP) [47,48]. The opening of the mitochondrial PTP can lead to a release of cytochrome C, which is a key event in apoptosis via the mitochondria-mediated pathway [49]. We examined expression of Bax and cytochrome C by Western blot. As shown in Figure 5A-B, after 24 h exposure at low concentration (0.05 mg/mL) of MNPs, the expression of Bax protein slightly increased, while without significant differences (P > 0.05). At high concentration (1 mg/mL), Bax protein expression in Fe3O4, OA-Fe3O4, and C-Fe MNPs-treated groups were about 1.94, 1.89, and 2.43 times compared with the control group, respectively. As for cytochrome C, the protein expression slightly decreased at the low concentration, while without significant differences (P > 0.05). At high concentration, the cytochrome C protein expression of all treated groups decreased dramatically, which is consistent with tendency of MMP. Based on the results mentioned above, we concluded that the three types of MNPs could induce Bax expression, further open PTP, and the PTP opening led to the release of cytochrome C from mitochondria. Once released from the mitochondria, cytochrome C combines with procaspase-9 to form the "apoptosome", which further activates caspase-3 [50-52]. Caspase-3 has been identified as a key mediator of apoptosis of mammalian cells [53]. Its activity is considered to be an appropriate measure of cytotoxic responsiveness [54]. We investigated the activaty of caspases-3 in BEL-7402 after exposure to MNPs for 24 h. As shown in Figure 6, we found that all three types of MNPs can activate caspase-3 in a dose-dependent manner. At low concentration (0.05 mg/mL), the activity of caspase-3 of the experimental groups increased, with significant differences found in Fe3O4- and C-Fe-treated groups (P < 0.05). The activity of caspase-3 was significantly increased in all experimental groups at high concentration (1 mg/mL) (P < 0.05).


Cytotoxic effects and the mechanism of three types of magnetic nanoparticles on human hepatoma BEL-7402 cells.

Kai W, Xiaojun X, Ximing P, Zhenqing H, Qiqing Z - Nanoscale Res Lett (2011)

Caspase-3 activity of BEL-7402 cells after incubation with MNPs for 24 h. After BEL-7402 cells were treated with MNPs (0.05 and 1 mg/mL) for 24 h, caspase-3 activity was determined using caspase-3/CPP32 Colorimetric Assay Kit. *P < 0.05 vs. control; **P < 0.01 vs. control.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211994&req=5

Figure 6: Caspase-3 activity of BEL-7402 cells after incubation with MNPs for 24 h. After BEL-7402 cells were treated with MNPs (0.05 and 1 mg/mL) for 24 h, caspase-3 activity was determined using caspase-3/CPP32 Colorimetric Assay Kit. *P < 0.05 vs. control; **P < 0.01 vs. control.
Mentions: Mitochondrial membrane permeability is regulated through a family of proto-oncogenes. Bax is an important pro-apoptotic protein of the Bcl-2 family members [46]. High level of Bax can translocate to the outer mitochondrial membrane (OMM) and insert into the OMM. Then, Bax forms oligomers that are thought to be important in the formation of the mitochondrial permeability transition pore (PTP) [47,48]. The opening of the mitochondrial PTP can lead to a release of cytochrome C, which is a key event in apoptosis via the mitochondria-mediated pathway [49]. We examined expression of Bax and cytochrome C by Western blot. As shown in Figure 5A-B, after 24 h exposure at low concentration (0.05 mg/mL) of MNPs, the expression of Bax protein slightly increased, while without significant differences (P > 0.05). At high concentration (1 mg/mL), Bax protein expression in Fe3O4, OA-Fe3O4, and C-Fe MNPs-treated groups were about 1.94, 1.89, and 2.43 times compared with the control group, respectively. As for cytochrome C, the protein expression slightly decreased at the low concentration, while without significant differences (P > 0.05). At high concentration, the cytochrome C protein expression of all treated groups decreased dramatically, which is consistent with tendency of MMP. Based on the results mentioned above, we concluded that the three types of MNPs could induce Bax expression, further open PTP, and the PTP opening led to the release of cytochrome C from mitochondria. Once released from the mitochondria, cytochrome C combines with procaspase-9 to form the "apoptosome", which further activates caspase-3 [50-52]. Caspase-3 has been identified as a key mediator of apoptosis of mammalian cells [53]. Its activity is considered to be an appropriate measure of cytotoxic responsiveness [54]. We investigated the activaty of caspases-3 in BEL-7402 after exposure to MNPs for 24 h. As shown in Figure 6, we found that all three types of MNPs can activate caspase-3 in a dose-dependent manner. At low concentration (0.05 mg/mL), the activity of caspase-3 of the experimental groups increased, with significant differences found in Fe3O4- and C-Fe-treated groups (P < 0.05). The activity of caspase-3 was significantly increased in all experimental groups at high concentration (1 mg/mL) (P < 0.05).

Bottom Line: The increase in apoptosis was accompanied with the Bax over-expression, mitochondrial membrane potential decrease, and the release of cytochrome C from mitochondria into cytosol.Our results revealed that certain concentrations of the three types of MNPs affect BEL-7402 cells viability via cell arrest and inducing apoptosis, and the MNPs-induced apoptosis is mediated through the mitochondrial-dependent pathway.The influence potency of MNPs observed in all experiments would be: C-Fe > Fe3O4 > OA-Fe3O4.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, PR China. qiq@xmu.edu.cn.

ABSTRACT
The evaluation of the toxicity of magnetic nanoparticles (MNPs) has attracted much attention in recent years. The current study aimed to investigate the cytotoxic effects of Fe3O4, oleic acid-coated Fe3O4 (OA-Fe3O4), and carbon-coated Fe (C-Fe) nanoparticles on human hepatoma BEL-7402 cells and the mechanisms. WST-1 assay demonstrated that the cytotoxicity of three types of MNPs was in a dose-dependent manner. G1 (Fe3O4 and OA-Fe3O4) phase and G2 (C-Fe) phase cell arrests and apoptosis induced by MNPs were detected by flow cytometry analysis. The increase in apoptosis was accompanied with the Bax over-expression, mitochondrial membrane potential decrease, and the release of cytochrome C from mitochondria into cytosol. Moreover, apoptosis was further confirmed by morphological and biochemical hallmarks, such as swollen mitochondria with lysing cristae and caspase-3 activation. Our results revealed that certain concentrations of the three types of MNPs affect BEL-7402 cells viability via cell arrest and inducing apoptosis, and the MNPs-induced apoptosis is mediated through the mitochondrial-dependent pathway. The influence potency of MNPs observed in all experiments would be: C-Fe > Fe3O4 > OA-Fe3O4.

No MeSH data available.


Related in: MedlinePlus