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Photoacoustic "nanobombs" fight against undesirable vesicular compartmentalization of anticancer drugs.

Chen A, Xu C, Li M, Zhang H, Wang D, Xia M, Meng G, Kang B, Chen H, Wei J - Sci Rep (2015)

Bottom Line: Strategies aimed at circumventing this problem may improve chemotherapeutic efficacy.Side effects were not observed.These findings provide insights of using nanotechnology to improve cancer chemotherapy, i.e. not only for drug delivery, but also for overcoming intracellular drug-transport hurdles.

View Article: PubMed Central - PubMed

Affiliation: Jiangsu Key Laboratory of Molecular Medicine, Medical School and the State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, 210093, China.

ABSTRACT
Undesirable intracellular vesicular compartmentalization of anticancer drugs in cancer cells is a common cause of chemoresistance. Strategies aimed at circumventing this problem may improve chemotherapeutic efficacy. We report a novel photophysical strategy for controlled-disruption of vesicular sequestration of the anticancer drug doxorubicin (DOX). Single-walled carbon nanotubes (SWCNTs), modified with folate, were trapped in acidic vesicles after entering lung cancer cells. Upon irradiation by near-infrared pulsed laser, these vesicles were massively broken by the resulting photoacoustic shockwave, and the vesicle-sequestered contents were released, leading to redistribution of DOX from cytoplasm to the target-containing nucleus. Redistribution resulted in 12-fold decrease of the EC50 of DOX in lung cancer cells, and enhanced antitumor efficacy of low-dose DOX in tumor-bearing mice. Side effects were not observed. These findings provide insights of using nanotechnology to improve cancer chemotherapy, i.e. not only for drug delivery, but also for overcoming intracellular drug-transport hurdles.

No MeSH data available.


Related in: MedlinePlus

Photoacoustic “nanobombs” selectively disrupt acidic vesicles.(a) A549 cells were pretreated with LysoTacker Green (green dots) for 1 h followed by incubation with FA-SWCNT-6G (red dots). The dynamic intracellular distribution was monitored by confocal fluorescence microscopy at 15, 30, and 60 min after FA-SWCNT-6G incubation. Yellow puncta depict colocalization of Lysotracker (green) and FA-SWCNT-6G (red) dots. The bottom panel shows the phase contrast of A549 cells. Scale bars = 10 μm. (b,c) A549 cells were pretreated with LysoTracker Green for 1 h followed by incubation with FA-SWCNT-6G for another hour. Cells were then irradiated or not for 15 min, and (b) subjected immediately to confocal microscopy. Scale bars = 5 μm. (c) Intracellular vesicles were quantitatively ranked by size (<1μm or >1 μm) in cells without (left panel, n = 44) or with irradiation (right panel, n = 47). The percentage of each distribution is shown. (d,e) A549 cells were incubated with SWCNTs for 1 h and then treated with laser for 15 min. TEM showing vesicle morphology of cells before (d) and after (e) laser irradiation. Scale bar = 2 μm. Enlarged images show intracellular vacuoles (cyan arrows), and perforation of plasma membranes (orange arrows).
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f2: Photoacoustic “nanobombs” selectively disrupt acidic vesicles.(a) A549 cells were pretreated with LysoTacker Green (green dots) for 1 h followed by incubation with FA-SWCNT-6G (red dots). The dynamic intracellular distribution was monitored by confocal fluorescence microscopy at 15, 30, and 60 min after FA-SWCNT-6G incubation. Yellow puncta depict colocalization of Lysotracker (green) and FA-SWCNT-6G (red) dots. The bottom panel shows the phase contrast of A549 cells. Scale bars = 10 μm. (b,c) A549 cells were pretreated with LysoTracker Green for 1 h followed by incubation with FA-SWCNT-6G for another hour. Cells were then irradiated or not for 15 min, and (b) subjected immediately to confocal microscopy. Scale bars = 5 μm. (c) Intracellular vesicles were quantitatively ranked by size (<1μm or >1 μm) in cells without (left panel, n = 44) or with irradiation (right panel, n = 47). The percentage of each distribution is shown. (d,e) A549 cells were incubated with SWCNTs for 1 h and then treated with laser for 15 min. TEM showing vesicle morphology of cells before (d) and after (e) laser irradiation. Scale bar = 2 μm. Enlarged images show intracellular vacuoles (cyan arrows), and perforation of plasma membranes (orange arrows).

Mentions: We have previously shown that folate-conjugated carbon nanotubes could be internalized by cancer cells through receptor-mediated endocytosis23242527. Here, we further investigated the dynamic biodistribution of nanotubes taken up by cancer cells. We found that fluorescent dye-labeled SWCNTs (FA-SWCNT-6G) were largely sequestered into vesicles within 15 min of incubation with A549 cells. Furthermore, the FA-SWCNT-6G-containing vesicles were increasingly co-localized with lysosomes after 30 to 60 min, indicating that FA-SWCNT-6G were internalized and then trafficked into lysosomes (Fig. 2a).


Photoacoustic "nanobombs" fight against undesirable vesicular compartmentalization of anticancer drugs.

Chen A, Xu C, Li M, Zhang H, Wang D, Xia M, Meng G, Kang B, Chen H, Wei J - Sci Rep (2015)

Photoacoustic “nanobombs” selectively disrupt acidic vesicles.(a) A549 cells were pretreated with LysoTacker Green (green dots) for 1 h followed by incubation with FA-SWCNT-6G (red dots). The dynamic intracellular distribution was monitored by confocal fluorescence microscopy at 15, 30, and 60 min after FA-SWCNT-6G incubation. Yellow puncta depict colocalization of Lysotracker (green) and FA-SWCNT-6G (red) dots. The bottom panel shows the phase contrast of A549 cells. Scale bars = 10 μm. (b,c) A549 cells were pretreated with LysoTracker Green for 1 h followed by incubation with FA-SWCNT-6G for another hour. Cells were then irradiated or not for 15 min, and (b) subjected immediately to confocal microscopy. Scale bars = 5 μm. (c) Intracellular vesicles were quantitatively ranked by size (<1μm or >1 μm) in cells without (left panel, n = 44) or with irradiation (right panel, n = 47). The percentage of each distribution is shown. (d,e) A549 cells were incubated with SWCNTs for 1 h and then treated with laser for 15 min. TEM showing vesicle morphology of cells before (d) and after (e) laser irradiation. Scale bar = 2 μm. Enlarged images show intracellular vacuoles (cyan arrows), and perforation of plasma membranes (orange arrows).
© Copyright Policy - open-access
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4612315&req=5

f2: Photoacoustic “nanobombs” selectively disrupt acidic vesicles.(a) A549 cells were pretreated with LysoTacker Green (green dots) for 1 h followed by incubation with FA-SWCNT-6G (red dots). The dynamic intracellular distribution was monitored by confocal fluorescence microscopy at 15, 30, and 60 min after FA-SWCNT-6G incubation. Yellow puncta depict colocalization of Lysotracker (green) and FA-SWCNT-6G (red) dots. The bottom panel shows the phase contrast of A549 cells. Scale bars = 10 μm. (b,c) A549 cells were pretreated with LysoTracker Green for 1 h followed by incubation with FA-SWCNT-6G for another hour. Cells were then irradiated or not for 15 min, and (b) subjected immediately to confocal microscopy. Scale bars = 5 μm. (c) Intracellular vesicles were quantitatively ranked by size (<1μm or >1 μm) in cells without (left panel, n = 44) or with irradiation (right panel, n = 47). The percentage of each distribution is shown. (d,e) A549 cells were incubated with SWCNTs for 1 h and then treated with laser for 15 min. TEM showing vesicle morphology of cells before (d) and after (e) laser irradiation. Scale bar = 2 μm. Enlarged images show intracellular vacuoles (cyan arrows), and perforation of plasma membranes (orange arrows).
Mentions: We have previously shown that folate-conjugated carbon nanotubes could be internalized by cancer cells through receptor-mediated endocytosis23242527. Here, we further investigated the dynamic biodistribution of nanotubes taken up by cancer cells. We found that fluorescent dye-labeled SWCNTs (FA-SWCNT-6G) were largely sequestered into vesicles within 15 min of incubation with A549 cells. Furthermore, the FA-SWCNT-6G-containing vesicles were increasingly co-localized with lysosomes after 30 to 60 min, indicating that FA-SWCNT-6G were internalized and then trafficked into lysosomes (Fig. 2a).

Bottom Line: Strategies aimed at circumventing this problem may improve chemotherapeutic efficacy.Side effects were not observed.These findings provide insights of using nanotechnology to improve cancer chemotherapy, i.e. not only for drug delivery, but also for overcoming intracellular drug-transport hurdles.

View Article: PubMed Central - PubMed

Affiliation: Jiangsu Key Laboratory of Molecular Medicine, Medical School and the State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, 210093, China.

ABSTRACT
Undesirable intracellular vesicular compartmentalization of anticancer drugs in cancer cells is a common cause of chemoresistance. Strategies aimed at circumventing this problem may improve chemotherapeutic efficacy. We report a novel photophysical strategy for controlled-disruption of vesicular sequestration of the anticancer drug doxorubicin (DOX). Single-walled carbon nanotubes (SWCNTs), modified with folate, were trapped in acidic vesicles after entering lung cancer cells. Upon irradiation by near-infrared pulsed laser, these vesicles were massively broken by the resulting photoacoustic shockwave, and the vesicle-sequestered contents were released, leading to redistribution of DOX from cytoplasm to the target-containing nucleus. Redistribution resulted in 12-fold decrease of the EC50 of DOX in lung cancer cells, and enhanced antitumor efficacy of low-dose DOX in tumor-bearing mice. Side effects were not observed. These findings provide insights of using nanotechnology to improve cancer chemotherapy, i.e. not only for drug delivery, but also for overcoming intracellular drug-transport hurdles.

No MeSH data available.


Related in: MedlinePlus