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Exploitingthe Metal-Chelating Properties of the Drug Cargo for In Vivo Positron Emission Tomography Imagingof Liposomal Nanomedicines

View Article: PubMed Central - PubMed

ABSTRACT

Theclinical value of current and future nanomedicines can be improvedby introducing patient selection strategies based on noninvasive sensitivewhole-body imaging techniques such as positron emission tomography(PET). Thus, a broad method to radiolabel and track preformed nanomedicinessuch as liposomal drugs with PET radionuclides will have a wide impactin nanomedicine. Here, we introduce a simple and efficient PET radiolabelingmethod that exploits the metal-chelating properties of certain drugs(e.g., bisphosphonates such as alendronate and anthracyclinessuch as doxorubicin) and widely used ionophores to achieve excellentradiolabeling yields, purities, and stabilities with 89Zr, 52Mn, and 64Cu, and without the requirementof modification of the nanomedicine components. In a model of metastaticbreast cancer, we demonstrate that this technique allows quantificationof the biodistribution of a radiolabeled stealth liposomal nanomedicinecontaining alendronate that shows high uptake in primary tumors andmetastatic organs. The versatility, efficiency, simplicity, and GMPcompatibility of this method may enable submicrodosing imaging studiesof liposomal nanomedicines containing chelating drugs in humans andmay have clinical impact by facilitating the introduction of image-guidedtherapeutic strategies in current and future nanomedicine clinicalstudies.

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Related in: MedlinePlus

Multimodalimaging study with 89Zr-PLA in the 3E.Δ.NT/NSGmouse model of metastatic breast cancer. (A) Coronal and sagittalSPECT-CT (top) and PET-CT (bottom) images centered at the tumors ofthe same animal from 1 to 72 h after injection of 89Zr-PLA(4.6 MBq in 1.2 μmol lipid). SPECT-CT images show identicalbiodistribution of [99mTcO4]− over time with high uptake in endogenous hNIS-expressing organsand hNIS-expressing tumor cells in the tumor (T) and metastatic organs(LNmet and Lumet). PET-CT images show the increasinguptake of 89Zr over time in the primary tumor (T), spleen(Sp), liver (L), and bone (B) and decreasing uptake in blood pool/heart(H). (B) Time–activity curves (89Zr) based on thepreclinical imaging study shown in (a) (n = 5 from t = 1–72 h; n = 1 at t = 168 h). Organs have been segregated into ascending (left) anddescending uptake (right) for clarity. (C) Ex vivo biodistribution graph showing data for selected organs at t = 72 h of 89Zr-PLA in 3E.Δ.NT/NSG mice(black bars, n = 4), 89Zr-ALD in 3E.Δ.NT/NSGmice (white bars, n = 2), and 89Zr-PLAin non-tumor-bearing NSG mice (gray bars, n = 3).**P < 0.01. Two-tailed t-test(unpaired). Full ex vivo biodistribution data at t = 72 h are available in Table 1. (D) Selected tumor to organ ratios fromthe 89Zr-PLA/3E.Δ.NT/NSG study (n = 4) showing an increase over time. (E) Co-registered SPECT-PET-CTimages of the primary tumor (from left to right: sagittal, coronal,transverse) showing a high degree of colocalization and heterogeneityof the 89Zr (purple scale) and 99mTc signals(green scale) within the non-necrotic rim. (F) Autoradiography images(left, 99mTc; right, 89Zr) of coronal slicefrom the same tumor as in (e) showing high degree of colocalizationand heterogeneity of both signals. (G) Fluorescence imaging of anadjacent slice of the same tumor as in (e,f) showing both areas ofhigh colocalization of microvasculature (CD31-positive, red) and GFP-positive(green) cancer cells (GFP, left), and low colocalization (right).
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fig3: Multimodalimaging study with 89Zr-PLA in the 3E.Δ.NT/NSGmouse model of metastatic breast cancer. (A) Coronal and sagittalSPECT-CT (top) and PET-CT (bottom) images centered at the tumors ofthe same animal from 1 to 72 h after injection of 89Zr-PLA(4.6 MBq in 1.2 μmol lipid). SPECT-CT images show identicalbiodistribution of [99mTcO4]− over time with high uptake in endogenous hNIS-expressing organsand hNIS-expressing tumor cells in the tumor (T) and metastatic organs(LNmet and Lumet). PET-CT images show the increasinguptake of 89Zr over time in the primary tumor (T), spleen(Sp), liver (L), and bone (B) and decreasing uptake in blood pool/heart(H). (B) Time–activity curves (89Zr) based on thepreclinical imaging study shown in (a) (n = 5 from t = 1–72 h; n = 1 at t = 168 h). Organs have been segregated into ascending (left) anddescending uptake (right) for clarity. (C) Ex vivo biodistribution graph showing data for selected organs at t = 72 h of 89Zr-PLA in 3E.Δ.NT/NSG mice(black bars, n = 4), 89Zr-ALD in 3E.Δ.NT/NSGmice (white bars, n = 2), and 89Zr-PLAin non-tumor-bearing NSG mice (gray bars, n = 3).**P < 0.01. Two-tailed t-test(unpaired). Full ex vivo biodistribution data at t = 72 h are available in Table 1. (D) Selected tumor to organ ratios fromthe 89Zr-PLA/3E.Δ.NT/NSG study (n = 4) showing an increase over time. (E) Co-registered SPECT-PET-CTimages of the primary tumor (from left to right: sagittal, coronal,transverse) showing a high degree of colocalization and heterogeneityof the 89Zr (purple scale) and 99mTc signals(green scale) within the non-necrotic rim. (F) Autoradiography images(left, 99mTc; right, 89Zr) of coronal slicefrom the same tumor as in (e) showing high degree of colocalizationand heterogeneity of both signals. (G) Fluorescence imaging of anadjacent slice of the same tumor as in (e,f) showing both areas ofhigh colocalization of microvasculature (CD31-positive, red) and GFP-positive(green) cancer cells (GFP, left), and low colocalization (right).

Mentions: The PET-CT study (Figure 3A,B and Table S3) was consistentwith the stealth properties of PLA, showing mainly blood pool uptakeat t = 1 h. On the other hand, a control experimentof free 89Zr-alendronate (89Zr-ALD) resultedin high kidney/renal excretion and bone uptake 1 h post-administration,as expected for a small molecule bisphosphonate36 and/or free 89Zr37 (vide infra and Figure S3). The long-circulating nature of 89Zr-PLA is also evidentfrom the high signal in the heart during the study (from 31.2 ±7.2%ID/mL at 1 h to 8.32 ± 0.90%ID/mL at 72 h). The calculatedcirculation half-life, assuming first-order single-compartment pharmacokinetics,is 15 h, matching that of similar mouse studies with PEGylated liposomalbisphosphonates with identical lipid composition38 and other PEGylated liposomes.39


Exploitingthe Metal-Chelating Properties of the Drug Cargo for In Vivo Positron Emission Tomography Imagingof Liposomal Nanomedicines
Multimodalimaging study with 89Zr-PLA in the 3E.Δ.NT/NSGmouse model of metastatic breast cancer. (A) Coronal and sagittalSPECT-CT (top) and PET-CT (bottom) images centered at the tumors ofthe same animal from 1 to 72 h after injection of 89Zr-PLA(4.6 MBq in 1.2 μmol lipid). SPECT-CT images show identicalbiodistribution of [99mTcO4]− over time with high uptake in endogenous hNIS-expressing organsand hNIS-expressing tumor cells in the tumor (T) and metastatic organs(LNmet and Lumet). PET-CT images show the increasinguptake of 89Zr over time in the primary tumor (T), spleen(Sp), liver (L), and bone (B) and decreasing uptake in blood pool/heart(H). (B) Time–activity curves (89Zr) based on thepreclinical imaging study shown in (a) (n = 5 from t = 1–72 h; n = 1 at t = 168 h). Organs have been segregated into ascending (left) anddescending uptake (right) for clarity. (C) Ex vivo biodistribution graph showing data for selected organs at t = 72 h of 89Zr-PLA in 3E.Δ.NT/NSG mice(black bars, n = 4), 89Zr-ALD in 3E.Δ.NT/NSGmice (white bars, n = 2), and 89Zr-PLAin non-tumor-bearing NSG mice (gray bars, n = 3).**P < 0.01. Two-tailed t-test(unpaired). Full ex vivo biodistribution data at t = 72 h are available in Table 1. (D) Selected tumor to organ ratios fromthe 89Zr-PLA/3E.Δ.NT/NSG study (n = 4) showing an increase over time. (E) Co-registered SPECT-PET-CTimages of the primary tumor (from left to right: sagittal, coronal,transverse) showing a high degree of colocalization and heterogeneityof the 89Zr (purple scale) and 99mTc signals(green scale) within the non-necrotic rim. (F) Autoradiography images(left, 99mTc; right, 89Zr) of coronal slicefrom the same tumor as in (e) showing high degree of colocalizationand heterogeneity of both signals. (G) Fluorescence imaging of anadjacent slice of the same tumor as in (e,f) showing both areas ofhigh colocalization of microvasculature (CD31-positive, red) and GFP-positive(green) cancer cells (GFP, left), and low colocalization (right).
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fig3: Multimodalimaging study with 89Zr-PLA in the 3E.Δ.NT/NSGmouse model of metastatic breast cancer. (A) Coronal and sagittalSPECT-CT (top) and PET-CT (bottom) images centered at the tumors ofthe same animal from 1 to 72 h after injection of 89Zr-PLA(4.6 MBq in 1.2 μmol lipid). SPECT-CT images show identicalbiodistribution of [99mTcO4]− over time with high uptake in endogenous hNIS-expressing organsand hNIS-expressing tumor cells in the tumor (T) and metastatic organs(LNmet and Lumet). PET-CT images show the increasinguptake of 89Zr over time in the primary tumor (T), spleen(Sp), liver (L), and bone (B) and decreasing uptake in blood pool/heart(H). (B) Time–activity curves (89Zr) based on thepreclinical imaging study shown in (a) (n = 5 from t = 1–72 h; n = 1 at t = 168 h). Organs have been segregated into ascending (left) anddescending uptake (right) for clarity. (C) Ex vivo biodistribution graph showing data for selected organs at t = 72 h of 89Zr-PLA in 3E.Δ.NT/NSG mice(black bars, n = 4), 89Zr-ALD in 3E.Δ.NT/NSGmice (white bars, n = 2), and 89Zr-PLAin non-tumor-bearing NSG mice (gray bars, n = 3).**P < 0.01. Two-tailed t-test(unpaired). Full ex vivo biodistribution data at t = 72 h are available in Table 1. (D) Selected tumor to organ ratios fromthe 89Zr-PLA/3E.Δ.NT/NSG study (n = 4) showing an increase over time. (E) Co-registered SPECT-PET-CTimages of the primary tumor (from left to right: sagittal, coronal,transverse) showing a high degree of colocalization and heterogeneityof the 89Zr (purple scale) and 99mTc signals(green scale) within the non-necrotic rim. (F) Autoradiography images(left, 99mTc; right, 89Zr) of coronal slicefrom the same tumor as in (e) showing high degree of colocalizationand heterogeneity of both signals. (G) Fluorescence imaging of anadjacent slice of the same tumor as in (e,f) showing both areas ofhigh colocalization of microvasculature (CD31-positive, red) and GFP-positive(green) cancer cells (GFP, left), and low colocalization (right).
Mentions: The PET-CT study (Figure 3A,B and Table S3) was consistentwith the stealth properties of PLA, showing mainly blood pool uptakeat t = 1 h. On the other hand, a control experimentof free 89Zr-alendronate (89Zr-ALD) resultedin high kidney/renal excretion and bone uptake 1 h post-administration,as expected for a small molecule bisphosphonate36 and/or free 89Zr37 (vide infra and Figure S3). The long-circulating nature of 89Zr-PLA is also evidentfrom the high signal in the heart during the study (from 31.2 ±7.2%ID/mL at 1 h to 8.32 ± 0.90%ID/mL at 72 h). The calculatedcirculation half-life, assuming first-order single-compartment pharmacokinetics,is 15 h, matching that of similar mouse studies with PEGylated liposomalbisphosphonates with identical lipid composition38 and other PEGylated liposomes.39

View Article: PubMed Central - PubMed

ABSTRACT

Theclinical value of current and future nanomedicines can be improvedby introducing patient selection strategies based on noninvasive sensitivewhole-body imaging techniques such as positron emission tomography(PET). Thus, a broad method to radiolabel and track preformed nanomedicinessuch as liposomal drugs with PET radionuclides will have a wide impactin nanomedicine. Here, we introduce a simple and efficient PET radiolabelingmethod that exploits the metal-chelating properties of certain drugs(e.g., bisphosphonates such as alendronate and anthracyclinessuch as doxorubicin) and widely used ionophores to achieve excellentradiolabeling yields, purities, and stabilities with 89Zr, 52Mn, and 64Cu, and without the requirementof modification of the nanomedicine components. In a model of metastaticbreast cancer, we demonstrate that this technique allows quantificationof the biodistribution of a radiolabeled stealth liposomal nanomedicinecontaining alendronate that shows high uptake in primary tumors andmetastatic organs. The versatility, efficiency, simplicity, and GMPcompatibility of this method may enable submicrodosing imaging studiesof liposomal nanomedicines containing chelating drugs in humans andmay have clinical impact by facilitating the introduction of image-guidedtherapeutic strategies in current and future nanomedicine clinicalstudies.

No MeSH data available.


Related in: MedlinePlus