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Comparative assessment of the apoptotic potential of silver nanoparticles synthesized by Bacillus tequilensis and Calocybe indica in MDA-MB-231 human breast cancer cells: targeting p53 for anticancer therapy.

Gurunathan S, Park JH, Han JW, Kim JH - Int J Nanomedicine (2015)

Bottom Line: This is especially true in the area of nanomedicine, due to physicochemical properties, such as mechanical, chemical, magnetic, optical, and electrical properties, compared with bulk materials.The first goal of this study was to produce silver nanoparticles (AgNPs) using two different biological resources as reducing agents, Bacillus tequilensis and Calocybe indica.Cells pretreated with pifithrin-alpha were protected from p53-mediated AgNPs-induced toxicity.

View Article: PubMed Central - PubMed

Affiliation: Department of Animal Biotechnology, Konkuk University, Seoul, Republic of Korea.

ABSTRACT

Background: Recently, the use of nanotechnology has been expanding very rapidly in diverse areas of research, such as consumer products, energy, materials, and medicine. This is especially true in the area of nanomedicine, due to physicochemical properties, such as mechanical, chemical, magnetic, optical, and electrical properties, compared with bulk materials. The first goal of this study was to produce silver nanoparticles (AgNPs) using two different biological resources as reducing agents, Bacillus tequilensis and Calocybe indica. The second goal was to investigate the apoptotic potential of the as-prepared AgNPs in breast cancer cells. The final goal was to investigate the role of p53 in the cellular response elicited by AgNPs.

Methods: The synthesis and characterization of AgNPs were assessed by various analytical techniques, including ultraviolet-visible (UV-vis) spectroscopy, X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, dynamic light scattering (DLS), and transmission electron microscopy (TEM). The apoptotic efficiency of AgNPs was confirmed using a series of assays, including cell viability, leakage of lactate dehydrogenase (LDH), production of reactive oxygen species (ROS), DNA fragmentation, mitochondrial membrane potential, and Western blot.

Results: The absorption spectrum of the yellow AgNPs showed the presence of nanoparticles. XRD and FTIR spectroscopy results confirmed the crystal structure and biomolecules involved in the synthesis of AgNPs. The AgNPs derived from bacteria and fungi showed distinguishable shapes, with an average size of 20 nm. Cell viability assays suggested a dose-dependent toxic effect of AgNPs, which was confirmed by leakage of LDH, activation of ROS, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)-positive cells in MDA-MB-231 breast cancer cells. Western blot analyses revealed that AgNPs induce cellular apoptosis via activation of p53, p-Erk1/2, and caspase-3 signaling, and downregulation of Bcl-2. Cells pretreated with pifithrin-alpha were protected from p53-mediated AgNPs-induced toxicity.

Conclusion: We have demonstrated a simple approach for the synthesis of AgNPs using the novel strains B. tequilensis and C. indica, as well as their mechanism of cell death in a p53-dependent manner in MDA-MB-231 human breast cancer cells. The present findings could provide insight for the future development of a suitable anticancer drug, which may lead to the development of novel nanotherapeutic molecules for the treatment of cancers.

No MeSH data available.


Related in: MedlinePlus

PFT-α inhibits B-AgNPs- and F-AgNPs-induced apoptosis in a p53-dependent manner.Notes: Cells were pretreated with PFT-α (10 μM) for 1 hour and then incubated with respective IC50 concentrations of B-AgNPs or F-AgNPs for 24 hours. Apoptosis was measured using the TUNEL assay.Abbreviations: B-AgNPs, bacterium-derived AgNPs; DAPI, 4′,6-diamidino-2-phenylindole; F-AgNPs, fungus-derived AgNPs; IC50, half-maximal inhibitory concentration; PFT- α, pifithrin-alpha; TUNEL, terminal deoxynucleotidyl transferase dUTP nick end labeling.
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f14-ijn-10-4203: PFT-α inhibits B-AgNPs- and F-AgNPs-induced apoptosis in a p53-dependent manner.Notes: Cells were pretreated with PFT-α (10 μM) for 1 hour and then incubated with respective IC50 concentrations of B-AgNPs or F-AgNPs for 24 hours. Apoptosis was measured using the TUNEL assay.Abbreviations: B-AgNPs, bacterium-derived AgNPs; DAPI, 4′,6-diamidino-2-phenylindole; F-AgNPs, fungus-derived AgNPs; IC50, half-maximal inhibitory concentration; PFT- α, pifithrin-alpha; TUNEL, terminal deoxynucleotidyl transferase dUTP nick end labeling.

Mentions: Liu et al reported that each cellular concentration and distribution pattern of p53 has a distinct cellular function and that ROS act as both an upstream signal that triggers p53 activation and as a downstream factor that mediates apoptosis.105 Here, we examined the role of PFT-α on p53 in regulating cellular apoptosis, and the mechanism by which PFT-α modulates p53 in AgNPs-induced apoptosis. Cells were preincubated with 10 μM PFT-α, and the inhibitory effect of PFT-α on apoptosis was analyzed using the TUNEL assay. The results show that PFT-α pretreated cells exhibited significantly decreased AgNPs-induced apoptosis (Figure 14). PFT-α is a small-molecule inhibitor shown to specifically inhibit the direct proapoptotic actions of p53 at mitochondria, by reducing the affinity of p53 toward its mitochondrial interaction partners Bcl-2, Bcl-XL, and Bak.106,107 Pretreatment with PFT-α was shown to rescue primary thymocytes in vitro and mice in vivo, from lethal doses of γ-irradiation or DNA-damaging agents.106,107 Thus, we used this inhibitor to determine the significance of the transcription-independent mitochondrial p53 death program during AgNPs-induced apoptosis. Indeed, cells pretreated with PFT-α prior to AgNPs exposure show decreased TUNEL staining in both B-AgNPs- and F-AgNPs-treated cells. Taken together, these results confirm the importance of the direct mitochondrial p53 death program in AgNPs-induced apoptosis.


Comparative assessment of the apoptotic potential of silver nanoparticles synthesized by Bacillus tequilensis and Calocybe indica in MDA-MB-231 human breast cancer cells: targeting p53 for anticancer therapy.

Gurunathan S, Park JH, Han JW, Kim JH - Int J Nanomedicine (2015)

PFT-α inhibits B-AgNPs- and F-AgNPs-induced apoptosis in a p53-dependent manner.Notes: Cells were pretreated with PFT-α (10 μM) for 1 hour and then incubated with respective IC50 concentrations of B-AgNPs or F-AgNPs for 24 hours. Apoptosis was measured using the TUNEL assay.Abbreviations: B-AgNPs, bacterium-derived AgNPs; DAPI, 4′,6-diamidino-2-phenylindole; F-AgNPs, fungus-derived AgNPs; IC50, half-maximal inhibitory concentration; PFT- α, pifithrin-alpha; TUNEL, terminal deoxynucleotidyl transferase dUTP nick end labeling.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4494182&req=5

f14-ijn-10-4203: PFT-α inhibits B-AgNPs- and F-AgNPs-induced apoptosis in a p53-dependent manner.Notes: Cells were pretreated with PFT-α (10 μM) for 1 hour and then incubated with respective IC50 concentrations of B-AgNPs or F-AgNPs for 24 hours. Apoptosis was measured using the TUNEL assay.Abbreviations: B-AgNPs, bacterium-derived AgNPs; DAPI, 4′,6-diamidino-2-phenylindole; F-AgNPs, fungus-derived AgNPs; IC50, half-maximal inhibitory concentration; PFT- α, pifithrin-alpha; TUNEL, terminal deoxynucleotidyl transferase dUTP nick end labeling.
Mentions: Liu et al reported that each cellular concentration and distribution pattern of p53 has a distinct cellular function and that ROS act as both an upstream signal that triggers p53 activation and as a downstream factor that mediates apoptosis.105 Here, we examined the role of PFT-α on p53 in regulating cellular apoptosis, and the mechanism by which PFT-α modulates p53 in AgNPs-induced apoptosis. Cells were preincubated with 10 μM PFT-α, and the inhibitory effect of PFT-α on apoptosis was analyzed using the TUNEL assay. The results show that PFT-α pretreated cells exhibited significantly decreased AgNPs-induced apoptosis (Figure 14). PFT-α is a small-molecule inhibitor shown to specifically inhibit the direct proapoptotic actions of p53 at mitochondria, by reducing the affinity of p53 toward its mitochondrial interaction partners Bcl-2, Bcl-XL, and Bak.106,107 Pretreatment with PFT-α was shown to rescue primary thymocytes in vitro and mice in vivo, from lethal doses of γ-irradiation or DNA-damaging agents.106,107 Thus, we used this inhibitor to determine the significance of the transcription-independent mitochondrial p53 death program during AgNPs-induced apoptosis. Indeed, cells pretreated with PFT-α prior to AgNPs exposure show decreased TUNEL staining in both B-AgNPs- and F-AgNPs-treated cells. Taken together, these results confirm the importance of the direct mitochondrial p53 death program in AgNPs-induced apoptosis.

Bottom Line: This is especially true in the area of nanomedicine, due to physicochemical properties, such as mechanical, chemical, magnetic, optical, and electrical properties, compared with bulk materials.The first goal of this study was to produce silver nanoparticles (AgNPs) using two different biological resources as reducing agents, Bacillus tequilensis and Calocybe indica.Cells pretreated with pifithrin-alpha were protected from p53-mediated AgNPs-induced toxicity.

View Article: PubMed Central - PubMed

Affiliation: Department of Animal Biotechnology, Konkuk University, Seoul, Republic of Korea.

ABSTRACT

Background: Recently, the use of nanotechnology has been expanding very rapidly in diverse areas of research, such as consumer products, energy, materials, and medicine. This is especially true in the area of nanomedicine, due to physicochemical properties, such as mechanical, chemical, magnetic, optical, and electrical properties, compared with bulk materials. The first goal of this study was to produce silver nanoparticles (AgNPs) using two different biological resources as reducing agents, Bacillus tequilensis and Calocybe indica. The second goal was to investigate the apoptotic potential of the as-prepared AgNPs in breast cancer cells. The final goal was to investigate the role of p53 in the cellular response elicited by AgNPs.

Methods: The synthesis and characterization of AgNPs were assessed by various analytical techniques, including ultraviolet-visible (UV-vis) spectroscopy, X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, dynamic light scattering (DLS), and transmission electron microscopy (TEM). The apoptotic efficiency of AgNPs was confirmed using a series of assays, including cell viability, leakage of lactate dehydrogenase (LDH), production of reactive oxygen species (ROS), DNA fragmentation, mitochondrial membrane potential, and Western blot.

Results: The absorption spectrum of the yellow AgNPs showed the presence of nanoparticles. XRD and FTIR spectroscopy results confirmed the crystal structure and biomolecules involved in the synthesis of AgNPs. The AgNPs derived from bacteria and fungi showed distinguishable shapes, with an average size of 20 nm. Cell viability assays suggested a dose-dependent toxic effect of AgNPs, which was confirmed by leakage of LDH, activation of ROS, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)-positive cells in MDA-MB-231 breast cancer cells. Western blot analyses revealed that AgNPs induce cellular apoptosis via activation of p53, p-Erk1/2, and caspase-3 signaling, and downregulation of Bcl-2. Cells pretreated with pifithrin-alpha were protected from p53-mediated AgNPs-induced toxicity.

Conclusion: We have demonstrated a simple approach for the synthesis of AgNPs using the novel strains B. tequilensis and C. indica, as well as their mechanism of cell death in a p53-dependent manner in MDA-MB-231 human breast cancer cells. The present findings could provide insight for the future development of a suitable anticancer drug, which may lead to the development of novel nanotherapeutic molecules for the treatment of cancers.

No MeSH data available.


Related in: MedlinePlus