TY - JOUR
T1 - Necrosis binding of Ac-Lys0(IRDye800CW)-Tyr3-octreotate
T2 - a consequence from cyanine-labeling of small molecules
AU - Stroet, Marcus C.M.
AU - Dijkstra, Bianca M.
AU - Dulfer, Sebastiaan E.
AU - Kruijff, Schelto
AU - den Dunnen, Wilfred F.A.
AU - Kruyt, Frank A.E.
AU - Groen, Rob J.M.
AU - Seimbille, Yann
AU - Panth, Kranthi M.
AU - Mezzanotte, Laura
AU - Lowik, Clemens W.G.M.
AU - de Jong, Marion
N1 - Funding Information:
This research is funded with grant 11089–2017/1 from the Koningin Wilhelmina Foundation (KWF).
Funding Information:
All animal experiments were supported by research grants from the University of Groningen, the University Medical Center Groningen, and the de Cock-Hadders Stichting.
Publisher Copyright: © 2021, The Author(s).
PY - 2021/5/10
Y1 - 2021/5/10
N2 - Background: There is a growing body of nuclear contrast agents that are repurposed for fluorescence-guided surgery. New contrast agents are obtained by substituting the radioactive tag with, or adding a fluorescent cyanine to the molecular structure of antibodies or peptides. This enables intra-operative fluorescent detection of cancerous tissue, leading to more complete tumor resection. However, these fluorescent cyanines can have a remarkable influence on pharmacokinetics and tumor uptake, especially when labeled to smaller targeting vectors such as peptides. Here we demonstrate the effect of cyanine-mediated dead cell-binding of Ac-Lys0(IRDye800CW)-Tyr3-octreotate (800CW-TATE) and how this can be used as an advantage for fluorescence-guided surgery. Results: Binding of 800CW-TATE could be blocked with DOTA0-Tyr3-octreotate (DOTA-TATE) on cultured SSTR2-positive U2OS cells and was absent in SSTR2 negative U2OS cells. However, strong binding was observed to dead cells, which could not be blocked with DOTA-TATE and was also present in dead SSTR2 negative cells. No SSTR2-mediated binding was observed in frozen tumor sections, possibly due to disruption of the cells in the process of sectioning the tissue before exposure to the contrast agent. DOTA-TATE blocking resulted in an incomplete reduction of 61.5 ± 5.8% fluorescence uptake by NCI-H69-tumors in mice. Near-infrared imaging and dead cell staining on paraffin sections from resected tumors revealed that fluorescence uptake persisted in necrotic regions upon blocking with DOTA-TATE. Conclusion: This study shows that labeling peptides with cyanines can result in dead cell binding. This does not hamper the ultimate purpose of fluorescence-guided surgery, as necrotic tissue appears in most solid tumors. Hence, the necrosis binding can increase the overall tumor uptake. Moreover, necrotic tissue should be removed as much as possible: it cannot be salvaged, causes inflammation, and is tumorigenic. However, when performing binding experiments to cells with disrupted membrane integrity, which is routinely done with nuclear probes, this dead cell-binding can resemble non-specific binding. This study will benefit the development of fluorescent contrast agents.
AB - Background: There is a growing body of nuclear contrast agents that are repurposed for fluorescence-guided surgery. New contrast agents are obtained by substituting the radioactive tag with, or adding a fluorescent cyanine to the molecular structure of antibodies or peptides. This enables intra-operative fluorescent detection of cancerous tissue, leading to more complete tumor resection. However, these fluorescent cyanines can have a remarkable influence on pharmacokinetics and tumor uptake, especially when labeled to smaller targeting vectors such as peptides. Here we demonstrate the effect of cyanine-mediated dead cell-binding of Ac-Lys0(IRDye800CW)-Tyr3-octreotate (800CW-TATE) and how this can be used as an advantage for fluorescence-guided surgery. Results: Binding of 800CW-TATE could be blocked with DOTA0-Tyr3-octreotate (DOTA-TATE) on cultured SSTR2-positive U2OS cells and was absent in SSTR2 negative U2OS cells. However, strong binding was observed to dead cells, which could not be blocked with DOTA-TATE and was also present in dead SSTR2 negative cells. No SSTR2-mediated binding was observed in frozen tumor sections, possibly due to disruption of the cells in the process of sectioning the tissue before exposure to the contrast agent. DOTA-TATE blocking resulted in an incomplete reduction of 61.5 ± 5.8% fluorescence uptake by NCI-H69-tumors in mice. Near-infrared imaging and dead cell staining on paraffin sections from resected tumors revealed that fluorescence uptake persisted in necrotic regions upon blocking with DOTA-TATE. Conclusion: This study shows that labeling peptides with cyanines can result in dead cell binding. This does not hamper the ultimate purpose of fluorescence-guided surgery, as necrotic tissue appears in most solid tumors. Hence, the necrosis binding can increase the overall tumor uptake. Moreover, necrotic tissue should be removed as much as possible: it cannot be salvaged, causes inflammation, and is tumorigenic. However, when performing binding experiments to cells with disrupted membrane integrity, which is routinely done with nuclear probes, this dead cell-binding can resemble non-specific binding. This study will benefit the development of fluorescent contrast agents.
UR - http://www.scopus.com/inward/record.url?scp=85105543560&partnerID=8YFLogxK
U2 - 10.1186/s13550-021-00789-4
DO - 10.1186/s13550-021-00789-4
M3 - Article
C2 - 33970376
AN - SCOPUS:85105543560
SN - 2191-219X
VL - 11
JO - EJNMMI Research
JF - EJNMMI Research
M1 - 47
ER -
