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In vivo lymphatic imaging of a human inflammatory breast cancer model.

Agollah GD, Wu G, Sevick-Muraca EM, Kwon S - J Cancer (2014)

Bottom Line: Inflammatory breast cancer (IBC) remains the most aggressive type of breast cancer with the greatest potential for metastasis and as a result, the highest mortality rate.Herein, we non-invasively and longitudinally imaged lymphatics in an animal model of IBC using near-infrared fluorescence (NIRF) imaging.We also observed increased and dilated fluorescent lymphatic vessels in the tumor periphery, which was confirmed by ex vivo immunohistochemical staining of lymphatic vessels.

View Article: PubMed Central - PubMed

Affiliation: 1. Center for Molecular Imaging, The Brown Foundation Institute of Molecular Medicine, The University of Texas Health Science Center, Houston, TX 77030; ; 2. The University of Texas Graduate School of Biomedical Sciences at Houston. The University of Texas MD Anderson Cancer Center, Houston, Texas 77030.

ABSTRACT

Background: Inflammatory breast cancer (IBC) remains the most aggressive type of breast cancer with the greatest potential for metastasis and as a result, the highest mortality rate. IBC cells invade and metastasize through dermal lymphatic vessels; however, it is unknown how lymphatic drainage patterns change during IBC growth and metastasis. Herein, we non-invasively and longitudinally imaged lymphatics in an animal model of IBC using near-infrared fluorescence (NIRF) imaging.

Materials and methods: Mice were imaged in vivo prior to, and up to 11 weeks after subcutaneous or orthotopic inoculation of human IBC SUM149 cells, which were stably transfected with infrared fluorescence protein (iRFP) gene reporter (SUM149-iRFP), following intradermal (i.d.) injection of indocyanine green (ICG).

Results: Fluorescence images showed well-defined lymphatic vessels prior to SUM149-iRFP inoculation. However, altered lymphatic drainage patterns including rerouting of lymphatic drainage were detected in mice with SUM149-iRFP, due to lymphatic obstruction of normal lymphatic drainages caused by tumor growth. In addition, we observed tortuous lymphatic vessels and extravasation of ICG-laden lymph in mice with SUM149-iRFP. We also observed increased and dilated fluorescent lymphatic vessels in the tumor periphery, which was confirmed by ex vivo immunohistochemical staining of lymphatic vessels.

Conclusions: Our pre-clinical studies demonstrate that non-invasive NIRF imaging can provide a method to assess changes in lymphatic drainage patterns during IBC growth and metastasis.

No MeSH data available.


Related in: MedlinePlus

White light, NIR, and iRFP fluorescent images prior to, 8 weeks, and 11 weeks after orthotopic inoculation of SUM149-iRFP cells to the inguinal MFP. NIR fluorescent images (green) of the lymphatics were merged with iRFP fluorescent images (red) of the gene reporter in the tumor. A magnified fluorescent image of the white rectangles was also acquired. Arrow, ILN. Double arrow, ICG injection site. Double open arrow, PLN. Broken arrow, IsLN. Arrow head, SUM149-iRFP tumor. Open arrow, lymphatic capillaries due to dermal backflow. Scale, 1 mm.
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Figure 3: White light, NIR, and iRFP fluorescent images prior to, 8 weeks, and 11 weeks after orthotopic inoculation of SUM149-iRFP cells to the inguinal MFP. NIR fluorescent images (green) of the lymphatics were merged with iRFP fluorescent images (red) of the gene reporter in the tumor. A magnified fluorescent image of the white rectangles was also acquired. Arrow, ILN. Double arrow, ICG injection site. Double open arrow, PLN. Broken arrow, IsLN. Arrow head, SUM149-iRFP tumor. Open arrow, lymphatic capillaries due to dermal backflow. Scale, 1 mm.

Mentions: SUM149-iRFP cells were orthotopically inoculated in the MFP of mice and visualized longitudinally over nine weeks following implantation (Figure 2). In conjunction with tumor growth assessment, we also performed lymphatic imaging to investigate how lymphatic drainage patterns change during disease progression. As reported previously 9, 10, ICG-laden lymph drained from the base of the tail, where ICG was injected, to the ILN and to the ALN. This drainage pathway was detected in nearly all mice imaged in this study, with the exception of one mouse (See Figure 3). Normal lymphatic drainage pathways to the ALN were observed up to 3 weeks post inoculation (p.i.), even as ICG accumulated proximally to the tumor. At 5 weeks p.i., we observed strong ICG fluorescence in the proximity of the tumor. Magnified fluorescent images acquired using a macrolens showed lymphatic capillary network (open arrow in Figure 2). Dynamic NIRF imaging (Additional file 1: video 1) demonstrated ICG dye accumulated anteriorly to the tumor, which exhibited both lateral and retrograde flow due to obstruction of normal lymphatic drainage towards the ILN by the tumor. At 7 weeks p.i, these anterior vessels were no longer observed; rather, new drainage pathways to the ALN had formed which bypassed both the tumor and tumor draining ILN (TdILN). By 9 weeks p.i., we observed rerouting of ICG-laden lymph to the ALN and the more tortuous and leaky lymphatic vessels (Additional file 2: video 2) as tumor burden increased.


In vivo lymphatic imaging of a human inflammatory breast cancer model.

Agollah GD, Wu G, Sevick-Muraca EM, Kwon S - J Cancer (2014)

White light, NIR, and iRFP fluorescent images prior to, 8 weeks, and 11 weeks after orthotopic inoculation of SUM149-iRFP cells to the inguinal MFP. NIR fluorescent images (green) of the lymphatics were merged with iRFP fluorescent images (red) of the gene reporter in the tumor. A magnified fluorescent image of the white rectangles was also acquired. Arrow, ILN. Double arrow, ICG injection site. Double open arrow, PLN. Broken arrow, IsLN. Arrow head, SUM149-iRFP tumor. Open arrow, lymphatic capillaries due to dermal backflow. Scale, 1 mm.
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Figure 3: White light, NIR, and iRFP fluorescent images prior to, 8 weeks, and 11 weeks after orthotopic inoculation of SUM149-iRFP cells to the inguinal MFP. NIR fluorescent images (green) of the lymphatics were merged with iRFP fluorescent images (red) of the gene reporter in the tumor. A magnified fluorescent image of the white rectangles was also acquired. Arrow, ILN. Double arrow, ICG injection site. Double open arrow, PLN. Broken arrow, IsLN. Arrow head, SUM149-iRFP tumor. Open arrow, lymphatic capillaries due to dermal backflow. Scale, 1 mm.
Mentions: SUM149-iRFP cells were orthotopically inoculated in the MFP of mice and visualized longitudinally over nine weeks following implantation (Figure 2). In conjunction with tumor growth assessment, we also performed lymphatic imaging to investigate how lymphatic drainage patterns change during disease progression. As reported previously 9, 10, ICG-laden lymph drained from the base of the tail, where ICG was injected, to the ILN and to the ALN. This drainage pathway was detected in nearly all mice imaged in this study, with the exception of one mouse (See Figure 3). Normal lymphatic drainage pathways to the ALN were observed up to 3 weeks post inoculation (p.i.), even as ICG accumulated proximally to the tumor. At 5 weeks p.i., we observed strong ICG fluorescence in the proximity of the tumor. Magnified fluorescent images acquired using a macrolens showed lymphatic capillary network (open arrow in Figure 2). Dynamic NIRF imaging (Additional file 1: video 1) demonstrated ICG dye accumulated anteriorly to the tumor, which exhibited both lateral and retrograde flow due to obstruction of normal lymphatic drainage towards the ILN by the tumor. At 7 weeks p.i, these anterior vessels were no longer observed; rather, new drainage pathways to the ALN had formed which bypassed both the tumor and tumor draining ILN (TdILN). By 9 weeks p.i., we observed rerouting of ICG-laden lymph to the ALN and the more tortuous and leaky lymphatic vessels (Additional file 2: video 2) as tumor burden increased.

Bottom Line: Inflammatory breast cancer (IBC) remains the most aggressive type of breast cancer with the greatest potential for metastasis and as a result, the highest mortality rate.Herein, we non-invasively and longitudinally imaged lymphatics in an animal model of IBC using near-infrared fluorescence (NIRF) imaging.We also observed increased and dilated fluorescent lymphatic vessels in the tumor periphery, which was confirmed by ex vivo immunohistochemical staining of lymphatic vessels.

View Article: PubMed Central - PubMed

Affiliation: 1. Center for Molecular Imaging, The Brown Foundation Institute of Molecular Medicine, The University of Texas Health Science Center, Houston, TX 77030; ; 2. The University of Texas Graduate School of Biomedical Sciences at Houston. The University of Texas MD Anderson Cancer Center, Houston, Texas 77030.

ABSTRACT

Background: Inflammatory breast cancer (IBC) remains the most aggressive type of breast cancer with the greatest potential for metastasis and as a result, the highest mortality rate. IBC cells invade and metastasize through dermal lymphatic vessels; however, it is unknown how lymphatic drainage patterns change during IBC growth and metastasis. Herein, we non-invasively and longitudinally imaged lymphatics in an animal model of IBC using near-infrared fluorescence (NIRF) imaging.

Materials and methods: Mice were imaged in vivo prior to, and up to 11 weeks after subcutaneous or orthotopic inoculation of human IBC SUM149 cells, which were stably transfected with infrared fluorescence protein (iRFP) gene reporter (SUM149-iRFP), following intradermal (i.d.) injection of indocyanine green (ICG).

Results: Fluorescence images showed well-defined lymphatic vessels prior to SUM149-iRFP inoculation. However, altered lymphatic drainage patterns including rerouting of lymphatic drainage were detected in mice with SUM149-iRFP, due to lymphatic obstruction of normal lymphatic drainages caused by tumor growth. In addition, we observed tortuous lymphatic vessels and extravasation of ICG-laden lymph in mice with SUM149-iRFP. We also observed increased and dilated fluorescent lymphatic vessels in the tumor periphery, which was confirmed by ex vivo immunohistochemical staining of lymphatic vessels.

Conclusions: Our pre-clinical studies demonstrate that non-invasive NIRF imaging can provide a method to assess changes in lymphatic drainage patterns during IBC growth and metastasis.

No MeSH data available.


Related in: MedlinePlus