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Image-Based Quantification of Benzoporphyrin Derivative Uptake, Localization, and Photobleaching in 3D Tumor Models, for Optimization of PDT Parameters.

Glidden MD, Celli JP, Massodi I, Rizvi I, Pogue BW, Hasan T - Theranostics (2012)

Bottom Line: While the systematic optimization of these treatment parameters can be complex, it also provides multiple avenues for enhancement of PDT efficacy under diverse treatment conditions, provided that a rational framework is established to quantify the impact of parameter selection upon treatment response.We use this approach to visualize and quantify the uptake, localization, and photobleaching of the PS benzoporphyrin derivative monoacid ring-A (BPD) in a range of treatment conditions with varying uptake times as well as continuous and fractionated light delivery regimens in 3D cultures of AsPC-1 and PANC-1 cells.Quantification of the spatial profile of cell killing within multicellular nodules revealed that these conditions also achieve the highest depth of cytotoxicity along the radial axis of 3D nodules.

View Article: PubMed Central - PubMed

Affiliation: 1. Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA 02114, USA; ; 2. Department of Physics, University of Massachusetts Boston, Boston, MA 02125, USA;

ABSTRACT
Photodynamic therapy (PDT) is a light-based treatment modality in which wavelength specific activation of a photosensitizer (PS) generates cytotoxic response in the irradiated region. PDT response is critically dependent on several parameters including light dose, PS dose, uptake time, fluence rate, and the mode of light delivery. While the systematic optimization of these treatment parameters can be complex, it also provides multiple avenues for enhancement of PDT efficacy under diverse treatment conditions, provided that a rational framework is established to quantify the impact of parameter selection upon treatment response. Here we present a theranostic technique, combining the inherent ability of the PS to serve simultaneously as a therapeutic and imaging agent, with the use of image-based treatment assessment in three dimensional (3D) in vitro tumor models, to comprise a platform to evaluate the impact of PDT parameters on treatment outcomes. We use this approach to visualize and quantify the uptake, localization, and photobleaching of the PS benzoporphyrin derivative monoacid ring-A (BPD) in a range of treatment conditions with varying uptake times as well as continuous and fractionated light delivery regimens in 3D cultures of AsPC-1 and PANC-1 cells. Informed by photobleaching patterns and correlation with cytotoxic response, asymmetric fractionated light delivery at 4 hours BPD uptake was found to be the most effective regimen assessed. Quantification of the spatial profile of cell killing within multicellular nodules revealed that these conditions also achieve the highest depth of cytotoxicity along the radial axis of 3D nodules. The framework introduced here provides a means for systematic assessment of PDT treatment parameters in biologically relevant 3D tumor models with potential for broader application to other systems.

No MeSH data available.


Related in: MedlinePlus

Depth of Cytotoxicity for Different Uptake and Light Delivery Treatments. (A) Inner and outer diameters and (B) calculated depth of cytotoxicity, reported as (outer diameter - inner diameter)/2, for day 12 AsPC-1 nodules given 1.5 hours and 4 hours of BPD uptake time and treated with 10 J/cm2 delivered either continuously or asymmetrically fractionated. Error bars correspond to the standard deviation of the five individual nodules selected per treatment group.
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Figure 6: Depth of Cytotoxicity for Different Uptake and Light Delivery Treatments. (A) Inner and outer diameters and (B) calculated depth of cytotoxicity, reported as (outer diameter - inner diameter)/2, for day 12 AsPC-1 nodules given 1.5 hours and 4 hours of BPD uptake time and treated with 10 J/cm2 delivered either continuously or asymmetrically fractionated. Error bars correspond to the standard deviation of the five individual nodules selected per treatment group.

Mentions: Figure 6 shows the results of this analysis for each group that received different BPD uptake time and irradiation schedules. A student's t-test analysis gave that there is no significant difference in the outer diameters (Figure 6A) of each group of nodules selected for line scan analysis. The inner diameter of the nodules collected from 4 hour uptake 10 J/cm2 33s/99s group, however, was significantly different (p=0.003) than the 1.5 hour fractionated group. This resulted in a significant difference in the depth of cytotoxicity (p=0.040), as presented in Figure 6B. The average cytotoxic depth of the 4 hour uptake fractionated group was also significantly thicker than in nodules that received both continuous irradiation treatments. There was a somewhat significant difference in the cytotoxic depth upon comparing continuous to fractionated light delivery (p=0.018) in the 1.5 hour uptake groups. Finally, there is a very significant change in cytotoxic depth when comparing continuous irradiation to fractionation with 4 hours of photosensitizer uptake (p=0.003).


Image-Based Quantification of Benzoporphyrin Derivative Uptake, Localization, and Photobleaching in 3D Tumor Models, for Optimization of PDT Parameters.

Glidden MD, Celli JP, Massodi I, Rizvi I, Pogue BW, Hasan T - Theranostics (2012)

Depth of Cytotoxicity for Different Uptake and Light Delivery Treatments. (A) Inner and outer diameters and (B) calculated depth of cytotoxicity, reported as (outer diameter - inner diameter)/2, for day 12 AsPC-1 nodules given 1.5 hours and 4 hours of BPD uptake time and treated with 10 J/cm2 delivered either continuously or asymmetrically fractionated. Error bars correspond to the standard deviation of the five individual nodules selected per treatment group.
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Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3475211&req=5

Figure 6: Depth of Cytotoxicity for Different Uptake and Light Delivery Treatments. (A) Inner and outer diameters and (B) calculated depth of cytotoxicity, reported as (outer diameter - inner diameter)/2, for day 12 AsPC-1 nodules given 1.5 hours and 4 hours of BPD uptake time and treated with 10 J/cm2 delivered either continuously or asymmetrically fractionated. Error bars correspond to the standard deviation of the five individual nodules selected per treatment group.
Mentions: Figure 6 shows the results of this analysis for each group that received different BPD uptake time and irradiation schedules. A student's t-test analysis gave that there is no significant difference in the outer diameters (Figure 6A) of each group of nodules selected for line scan analysis. The inner diameter of the nodules collected from 4 hour uptake 10 J/cm2 33s/99s group, however, was significantly different (p=0.003) than the 1.5 hour fractionated group. This resulted in a significant difference in the depth of cytotoxicity (p=0.040), as presented in Figure 6B. The average cytotoxic depth of the 4 hour uptake fractionated group was also significantly thicker than in nodules that received both continuous irradiation treatments. There was a somewhat significant difference in the cytotoxic depth upon comparing continuous to fractionated light delivery (p=0.018) in the 1.5 hour uptake groups. Finally, there is a very significant change in cytotoxic depth when comparing continuous irradiation to fractionation with 4 hours of photosensitizer uptake (p=0.003).

Bottom Line: While the systematic optimization of these treatment parameters can be complex, it also provides multiple avenues for enhancement of PDT efficacy under diverse treatment conditions, provided that a rational framework is established to quantify the impact of parameter selection upon treatment response.We use this approach to visualize and quantify the uptake, localization, and photobleaching of the PS benzoporphyrin derivative monoacid ring-A (BPD) in a range of treatment conditions with varying uptake times as well as continuous and fractionated light delivery regimens in 3D cultures of AsPC-1 and PANC-1 cells.Quantification of the spatial profile of cell killing within multicellular nodules revealed that these conditions also achieve the highest depth of cytotoxicity along the radial axis of 3D nodules.

View Article: PubMed Central - PubMed

Affiliation: 1. Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA 02114, USA; ; 2. Department of Physics, University of Massachusetts Boston, Boston, MA 02125, USA;

ABSTRACT
Photodynamic therapy (PDT) is a light-based treatment modality in which wavelength specific activation of a photosensitizer (PS) generates cytotoxic response in the irradiated region. PDT response is critically dependent on several parameters including light dose, PS dose, uptake time, fluence rate, and the mode of light delivery. While the systematic optimization of these treatment parameters can be complex, it also provides multiple avenues for enhancement of PDT efficacy under diverse treatment conditions, provided that a rational framework is established to quantify the impact of parameter selection upon treatment response. Here we present a theranostic technique, combining the inherent ability of the PS to serve simultaneously as a therapeutic and imaging agent, with the use of image-based treatment assessment in three dimensional (3D) in vitro tumor models, to comprise a platform to evaluate the impact of PDT parameters on treatment outcomes. We use this approach to visualize and quantify the uptake, localization, and photobleaching of the PS benzoporphyrin derivative monoacid ring-A (BPD) in a range of treatment conditions with varying uptake times as well as continuous and fractionated light delivery regimens in 3D cultures of AsPC-1 and PANC-1 cells. Informed by photobleaching patterns and correlation with cytotoxic response, asymmetric fractionated light delivery at 4 hours BPD uptake was found to be the most effective regimen assessed. Quantification of the spatial profile of cell killing within multicellular nodules revealed that these conditions also achieve the highest depth of cytotoxicity along the radial axis of 3D nodules. The framework introduced here provides a means for systematic assessment of PDT treatment parameters in biologically relevant 3D tumor models with potential for broader application to other systems.

No MeSH data available.


Related in: MedlinePlus