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Infrared laser pulse triggers increased singlet oxygen production in tumour cells.

Sokolovski SG, Zolotovskaya SA, Goltsov A, Pourreyron C, South AP, Rafailov EU - Sci Rep (2013)

Bottom Line: This technique utilises singlet oxygen ((1)O2) generation via a laser excited photosensitiser (PS) to kill cancer cells.However, prolonged sensitivity to intensive light (6-8 weeks for lung cancer), relatively low tissue penetration by activating light (630 nm up to 4 mm), and the cost of PS administration can limit progressive PDT applications.Our modelling and experimental results support the development of direct infrared (IR) laser-induced tumour treatment as a promising approach in tumour PDT.

View Article: PubMed Central - PubMed

Affiliation: Photonics and Nanoscience Group, School of Engineering, Physics and Mathematics, University of Dundee, Dundee DD1 4HN, UK.

ABSTRACT
Photodynamic therapy (PDT) is a technique developed to treat the ever-increasing global incidence of cancer. This technique utilises singlet oxygen ((1)O2) generation via a laser excited photosensitiser (PS) to kill cancer cells. However, prolonged sensitivity to intensive light (6-8 weeks for lung cancer), relatively low tissue penetration by activating light (630 nm up to 4 mm), and the cost of PS administration can limit progressive PDT applications. The development of quantum-dot laser diodes emitting in the highest absorption region (1268 nm) of triplet oxygen ((3)O2) presents the possibility of inducing apoptosis in tumour cells through direct (3)O2 → (1)O2 transition. Here we demonstrate that a single laser pulse triggers dose-dependent (1)O2 generation in both normal keratinocytes and tumour cells and show that tumour cells yield the highest (1)O2 far beyond the initial laser pulse exposure. Our modelling and experimental results support the development of direct infrared (IR) laser-induced tumour treatment as a promising approach in tumour PDT.

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Related in: MedlinePlus

Effect of irradiations on (A) calcium ratio in HaCaT (1268 nm), HeLa (1268 nm) cells, and both cell lines with 830 nm (control). Mean of n = 4, 10–15 cells per each ± SE; (B) Single channel currents recorded at −100 mV holding voltage at cell-attached configuration before (I), during (II), and after (III) 1268 nm laser irradiation of 47.7 J/cm2. (6 cells). Right-hand segment: opened channel events point-amplitude.
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f2: Effect of irradiations on (A) calcium ratio in HaCaT (1268 nm), HeLa (1268 nm) cells, and both cell lines with 830 nm (control). Mean of n = 4, 10–15 cells per each ± SE; (B) Single channel currents recorded at −100 mV holding voltage at cell-attached configuration before (I), during (II), and after (III) 1268 nm laser irradiation of 47.7 J/cm2. (6 cells). Right-hand segment: opened channel events point-amplitude.

Mentions: Products of oxidative stress (ROS, NO, organic radicals, etc.) are recognized as powerful regulatory messengers in cell signalling which very often affect cell calcium homeostasis28. In turn calcium homeostasis disruption can contribute to oxidative stress29. From our results, we anticipated that laser-induced 1O2 production could reflect on cytosolic calcium concentration ([Ca2+]cyt). Therefore single cell ratiometric Ca2+ imaging was employed to estimate calcium response of the HaCaT and HeLa cell lines after 1268 nm irradiation of 47.7 J/cm2 (Fig. 2A). Imaging showed an apparent increase in the fluorescence ratio by more than 1.2 times for HaCaT and HeLa cells, registered immediately after the laser was on. Following the cessation of irradiation, [Ca2+]cyt was measured for at least 7 min and found to continue rising in HaCaT cells whilst in contrast to the laser-induced singlet oxygen response, HeLa cells demonstrated plateau (discussed below). Further application of NaOCl (100 μM) induced a typical oxidative-stress-like calcium response in all cell lines (Fig. 2A). The LD emitting at 830 nm also temporally increased calcium fluorescence in both cell types falling to basic levels after the pulse was terminated.


Infrared laser pulse triggers increased singlet oxygen production in tumour cells.

Sokolovski SG, Zolotovskaya SA, Goltsov A, Pourreyron C, South AP, Rafailov EU - Sci Rep (2013)

Effect of irradiations on (A) calcium ratio in HaCaT (1268 nm), HeLa (1268 nm) cells, and both cell lines with 830 nm (control). Mean of n = 4, 10–15 cells per each ± SE; (B) Single channel currents recorded at −100 mV holding voltage at cell-attached configuration before (I), during (II), and after (III) 1268 nm laser irradiation of 47.7 J/cm2. (6 cells). Right-hand segment: opened channel events point-amplitude.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3860013&req=5

f2: Effect of irradiations on (A) calcium ratio in HaCaT (1268 nm), HeLa (1268 nm) cells, and both cell lines with 830 nm (control). Mean of n = 4, 10–15 cells per each ± SE; (B) Single channel currents recorded at −100 mV holding voltage at cell-attached configuration before (I), during (II), and after (III) 1268 nm laser irradiation of 47.7 J/cm2. (6 cells). Right-hand segment: opened channel events point-amplitude.
Mentions: Products of oxidative stress (ROS, NO, organic radicals, etc.) are recognized as powerful regulatory messengers in cell signalling which very often affect cell calcium homeostasis28. In turn calcium homeostasis disruption can contribute to oxidative stress29. From our results, we anticipated that laser-induced 1O2 production could reflect on cytosolic calcium concentration ([Ca2+]cyt). Therefore single cell ratiometric Ca2+ imaging was employed to estimate calcium response of the HaCaT and HeLa cell lines after 1268 nm irradiation of 47.7 J/cm2 (Fig. 2A). Imaging showed an apparent increase in the fluorescence ratio by more than 1.2 times for HaCaT and HeLa cells, registered immediately after the laser was on. Following the cessation of irradiation, [Ca2+]cyt was measured for at least 7 min and found to continue rising in HaCaT cells whilst in contrast to the laser-induced singlet oxygen response, HeLa cells demonstrated plateau (discussed below). Further application of NaOCl (100 μM) induced a typical oxidative-stress-like calcium response in all cell lines (Fig. 2A). The LD emitting at 830 nm also temporally increased calcium fluorescence in both cell types falling to basic levels after the pulse was terminated.

Bottom Line: This technique utilises singlet oxygen ((1)O2) generation via a laser excited photosensitiser (PS) to kill cancer cells.However, prolonged sensitivity to intensive light (6-8 weeks for lung cancer), relatively low tissue penetration by activating light (630 nm up to 4 mm), and the cost of PS administration can limit progressive PDT applications.Our modelling and experimental results support the development of direct infrared (IR) laser-induced tumour treatment as a promising approach in tumour PDT.

View Article: PubMed Central - PubMed

Affiliation: Photonics and Nanoscience Group, School of Engineering, Physics and Mathematics, University of Dundee, Dundee DD1 4HN, UK.

ABSTRACT
Photodynamic therapy (PDT) is a technique developed to treat the ever-increasing global incidence of cancer. This technique utilises singlet oxygen ((1)O2) generation via a laser excited photosensitiser (PS) to kill cancer cells. However, prolonged sensitivity to intensive light (6-8 weeks for lung cancer), relatively low tissue penetration by activating light (630 nm up to 4 mm), and the cost of PS administration can limit progressive PDT applications. The development of quantum-dot laser diodes emitting in the highest absorption region (1268 nm) of triplet oxygen ((3)O2) presents the possibility of inducing apoptosis in tumour cells through direct (3)O2 → (1)O2 transition. Here we demonstrate that a single laser pulse triggers dose-dependent (1)O2 generation in both normal keratinocytes and tumour cells and show that tumour cells yield the highest (1)O2 far beyond the initial laser pulse exposure. Our modelling and experimental results support the development of direct infrared (IR) laser-induced tumour treatment as a promising approach in tumour PDT.

Show MeSH
Related in: MedlinePlus