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Grafting aptamers onto gold nanostars increases in vitro efficacy in a wide range of cancer cell types.

Dam DH, Culver KS, Odom TW - Mol. Pharm. (2014)

Bottom Line: We report the design of a nanoconstruct that can function as a cell-type independent agent by targeting the ubiquitous protein nucleolin.Apt-AuNS resulted in downregulation of antiapoptotic Bcl-2 mRNA expression by ca. 200% compared to cells without the nanoconstructs.In contrast, treatments of the nanoconstructs with or without light-triggered release on a panel of normal cell lines had no adverse effects.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States.

ABSTRACT
We report the design of a nanoconstruct that can function as a cell-type independent agent by targeting the ubiquitous protein nucleolin. Gold nanostars (AuNS) loaded with high densities of nucleolin-specific DNA aptamer AS1411 (Apt-AuNS) produced anticancer effects in a panel of 12 cancer lines containing four representative subcategories. We found that the nanoconstructs could be internalized by cancer cells and trafficked to perinuclear regions. Apt-AuNS resulted in downregulation of antiapoptotic Bcl-2 mRNA expression by ca. 200% compared to cells without the nanoconstructs. The caspase 3/7 activity (apoptosis) and cell death in cancer cells treated with Apt-AuNS increased by 1.5 times and by ca. 17%, respectively, compared to cells treated with free AS1411 at over 10 times the concentration. Moreover, light-triggered release of aptamer from the AuNS further enhanced the in vitro efficacy of the nanoconstructs in the cancer line panel with a 2-fold increase in caspase activity and a 40% decrease in cell viability compared to treatment with Apt-AuNS only. In contrast, treatments of the nanoconstructs with or without light-triggered release on a panel of normal cell lines had no adverse effects.

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Light-triggered release of Apt from AuNS increasesthe percentagecell death. Cell viability analysis showed a 70% decrease of cellviability after aptamer release. Approximately 25% decrease in cellviability after treated with Apt-AuNS. Cancer cells treated with 450nM of free AS1411 showed reduced effects on cell death (less than10%) compared to those treated with 0.3 nM Apt-AuNS (33 nM AS1411)and three times lower than that from light-triggered treatment. Nosignificant cell death was observed in any of the normal cell lines. p-values were determined using a one-way ANOVA test. Linesover bars indicate groups that are not significantly different. (*)and (**) indicate p < 0.05 and p < 0.1, respectively.
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fig7: Light-triggered release of Apt from AuNS increasesthe percentagecell death. Cell viability analysis showed a 70% decrease of cellviability after aptamer release. Approximately 25% decrease in cellviability after treated with Apt-AuNS. Cancer cells treated with 450nM of free AS1411 showed reduced effects on cell death (less than10%) compared to those treated with 0.3 nM Apt-AuNS (33 nM AS1411)and three times lower than that from light-triggered treatment. Nosignificant cell death was observed in any of the normal cell lines. p-values were determined using a one-way ANOVA test. Linesover bars indicate groups that are not significantly different. (*)and (**) indicate p < 0.05 and p < 0.1, respectively.

Mentions: Because Bcl-2 mRNA functions as an antiapoptotic gene thatpreventscancer cells from entering programmed cell death, downregulation ofBcl-2 expression can trigger apoptosis.35 When cells undergo apoptosis, their caspase activities are oftenelevated.36 We measured the caspase 3/7activity of the 12-cancer cell panel (SupportingInformation, Materials and Methods) and found that the caspaseactivities increased by ca. 1.5 times after a single 7 h incubationwith Apt-AuNS. Note: we define the time after this 7 h incubationand after removal of the nanoconstructs as time t = 0. At t = 72 h, when control populations wereclose to 100% confluent, the activity of the proteases increased upto four times in HCT-116 (colon cancer) cells relative to untreatedcells (Figure 6, blue bar). Cell viabilitywas measured using a Cell-titer Blue assay to determine the percentageof live cells in the population (Supporting Information, Materials and Methods). Seventy-two hours after Apt-AuNS incubation,the average cell viability decreased by 25% (Figure 7, blue bar). The highest amount of cell death (ca. 40%) wasrecorded in SK-MEL-2 and DU-145 cells.


Grafting aptamers onto gold nanostars increases in vitro efficacy in a wide range of cancer cell types.

Dam DH, Culver KS, Odom TW - Mol. Pharm. (2014)

Light-triggered release of Apt from AuNS increasesthe percentagecell death. Cell viability analysis showed a 70% decrease of cellviability after aptamer release. Approximately 25% decrease in cellviability after treated with Apt-AuNS. Cancer cells treated with 450nM of free AS1411 showed reduced effects on cell death (less than10%) compared to those treated with 0.3 nM Apt-AuNS (33 nM AS1411)and three times lower than that from light-triggered treatment. Nosignificant cell death was observed in any of the normal cell lines. p-values were determined using a one-way ANOVA test. Linesover bars indicate groups that are not significantly different. (*)and (**) indicate p < 0.05 and p < 0.1, respectively.
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Related In: Results  -  Collection

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fig7: Light-triggered release of Apt from AuNS increasesthe percentagecell death. Cell viability analysis showed a 70% decrease of cellviability after aptamer release. Approximately 25% decrease in cellviability after treated with Apt-AuNS. Cancer cells treated with 450nM of free AS1411 showed reduced effects on cell death (less than10%) compared to those treated with 0.3 nM Apt-AuNS (33 nM AS1411)and three times lower than that from light-triggered treatment. Nosignificant cell death was observed in any of the normal cell lines. p-values were determined using a one-way ANOVA test. Linesover bars indicate groups that are not significantly different. (*)and (**) indicate p < 0.05 and p < 0.1, respectively.
Mentions: Because Bcl-2 mRNA functions as an antiapoptotic gene thatpreventscancer cells from entering programmed cell death, downregulation ofBcl-2 expression can trigger apoptosis.35 When cells undergo apoptosis, their caspase activities are oftenelevated.36 We measured the caspase 3/7activity of the 12-cancer cell panel (SupportingInformation, Materials and Methods) and found that the caspaseactivities increased by ca. 1.5 times after a single 7 h incubationwith Apt-AuNS. Note: we define the time after this 7 h incubationand after removal of the nanoconstructs as time t = 0. At t = 72 h, when control populations wereclose to 100% confluent, the activity of the proteases increased upto four times in HCT-116 (colon cancer) cells relative to untreatedcells (Figure 6, blue bar). Cell viabilitywas measured using a Cell-titer Blue assay to determine the percentageof live cells in the population (Supporting Information, Materials and Methods). Seventy-two hours after Apt-AuNS incubation,the average cell viability decreased by 25% (Figure 7, blue bar). The highest amount of cell death (ca. 40%) wasrecorded in SK-MEL-2 and DU-145 cells.

Bottom Line: We report the design of a nanoconstruct that can function as a cell-type independent agent by targeting the ubiquitous protein nucleolin.Apt-AuNS resulted in downregulation of antiapoptotic Bcl-2 mRNA expression by ca. 200% compared to cells without the nanoconstructs.In contrast, treatments of the nanoconstructs with or without light-triggered release on a panel of normal cell lines had no adverse effects.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States.

ABSTRACT
We report the design of a nanoconstruct that can function as a cell-type independent agent by targeting the ubiquitous protein nucleolin. Gold nanostars (AuNS) loaded with high densities of nucleolin-specific DNA aptamer AS1411 (Apt-AuNS) produced anticancer effects in a panel of 12 cancer lines containing four representative subcategories. We found that the nanoconstructs could be internalized by cancer cells and trafficked to perinuclear regions. Apt-AuNS resulted in downregulation of antiapoptotic Bcl-2 mRNA expression by ca. 200% compared to cells without the nanoconstructs. The caspase 3/7 activity (apoptosis) and cell death in cancer cells treated with Apt-AuNS increased by 1.5 times and by ca. 17%, respectively, compared to cells treated with free AS1411 at over 10 times the concentration. Moreover, light-triggered release of aptamer from the AuNS further enhanced the in vitro efficacy of the nanoconstructs in the cancer line panel with a 2-fold increase in caspase activity and a 40% decrease in cell viability compared to treatment with Apt-AuNS only. In contrast, treatments of the nanoconstructs with or without light-triggered release on a panel of normal cell lines had no adverse effects.

Show MeSH
Related in: MedlinePlus