Anchal Ghai - Academia.edu (original) (raw)
Papers by Anchal Ghai
Molecular imaging and biology, Mar 13, 2024
Purpose Multiple myeloma (MM) affects over 35,000 patients each year in the US. There remains a n... more Purpose Multiple myeloma (MM) affects over 35,000 patients each year in the US. There remains a need for versatile Positron Emission Tomography (PET) tracers for the detection, accurate staging, and monitoring of treatment response of MM that have optimal specificity and translational attributes. CD38 is uniformly overexpressed in MM and thus represents an ideal target to develop CD38-targeted small molecule PET radiopharmaceuticals to address these challenges. Procedures Using phage display peptide libraries and pioneering algorithms, we identified novel CD38 specific peptides. Imaging bioconjugates were synthesized using solid phase peptide chemistry, and systematically analyzed in vitro and in vivo in relevant MM systems. The CD38-targeted bioconjugates were radiolabeled with copper-64 ( 64 Cu) with100% radiochemical purity and an average specific activity of 3.3 -6.6 MBq/nmol. The analog NODAGA-PEG4-SL022-GGS (SL022: Thr-His-Tyr-Pro-Ile-Val-Ile) had a K d of 7.55 ± 0.291 nM and was chosen as the lead candidate. 64 Cu-NODAGA-PEG4-SL022-GGS demonstrated high binding affinity to CD38 expressing human myeloma MM.1S-CBR-GFP-WT cells, which was blocked by the nonradiolabeled version of the peptide analog and anti-CD38 clinical antibodies, daratumumab and isatuximab, by 58%, 73%, and 78%, respectively. The CD38 positive MM.1S-CBR-GFP-WT cells had > 68% enhanced cellular binding when compared to MM.1S-CBR-GFP-KO cells devoid of CD38. Furthermore, our new CD38-targeted radiopharmaceutical allowed visualization of tumors located in marrow rich bones, remaining there for up to 4 h. Clearance from non-target organs occurred within 60 min. Quantitative PET data from a murine disseminated tumor model showed significantly higher accumulation in the bones of tumor-bearing animals compared to tumor-naïve animals (SUV max 2.06 ± 0.4 versus 1.24 ± 0.4, P = 0.02). Independently, tumor uptake of the target compound was significantly higher (P = 0.003) compared to the scrambled peptide, 64 Cu-NODAGA-PEG4-SL041-GGS (SL041: Thr-Tyr-His-Ile-Pro-Ile-Val). The subcutaneous MM model demonstrated significantly higher accumulation in tumors compared to muscle at 1 and 4 h after tracer administration (SUV max 0.8 ± 0.2 and 0.14 ± 0.04, P = 0.04 at 1 h; SUV max 0.89 ± 0.01 and 0.09 ± 0.01, P = 0.0002 at 4 h). Conclusions The novel CD38-targeted, radiolabeled bioconjugates were specific and allowed visualization of MM, providing a starting point for the clinical translation of such tracers for the detection of MM.
The American Journal of Gastroenterology, Apr 1, 2013
Research Square (Research Square), Jul 9, 2021
Multiple myeloma (MM) is a disease of cancerous plasma cells. Current treatments have improved th... more Multiple myeloma (MM) is a disease of cancerous plasma cells. Current treatments have improved the survival rate; however, most MM patients relapse. Imaging based timely determination of therapeutic response is critical for improving outcomes in MM patients. Very late antigen-4 (VLA4) is over expressed in MM cells. Here, we evaluated [ 18 F]FDG and VLA4 targeted [ 64 Cu]LLP2A for quantitative PET imaging in MM models of variable VLA4 expression, and following bortezomib therapy. In vitro and ex vivo VLA4 expression was evaluated by ow cytometry. Human MM cells, MM.1S-CG and U266-CG (CG: luciferase and green uorescent protein), were injected intravenously in NOD-SCID gamma mice. Tumor progression was monitored by bioluminescence imaging (BLI). Treatment group received bortezomib (1mg/kg, twice/week) intraperitoneally. All cohorts (treated, untreated and no-tumor) were longitudinally imaged with [ 64 Cu]LLP2A (2-3 MBq; Molar Activity: 44.14±1.40 MBq/nmol) and [ 18 F]FDG (7.4-8.0 MBq) PET respectively. Flow cytometry con rmed high expression of CD49d in U266 cells (>99%) and moderate expression in MM.1S cells (~52%). BLI showed decrease in total body ux in treated mice. In MM.1S-CG untreated versus treated mice, [ 64 Cu]LLP2A localized with a signi cantly higher SUV mean in spine (0.58 versus 0.31) and femur (0.72 versus 0.39) at week 4 post tumor inoculation. In U266-CG treated versus untreated mice, there was a 4-time percent [ 64 Cu]LLP2A increase in spine at week 3. Compared to [ 64 Cu]LLP2A, [ 18 F]FDG PET detected treatment related changes at later time points. [ 64 Cu]LLP2A is a promising tracer for in vivo assessment of therapeutic response in disseminated models of MM.
Photodiagnosis and Photodynamic Therapy, Mar 1, 2023
Photodiagnosis and Photodynamic Therapy
Journal of bone oncology, Apr 1, 2024
The Journal of Nuclear Medicine, Aug 25, 2022
Background: There remains an unmet need for molecularly targeted imaging agents in multiple myelo... more Background: There remains an unmet need for molecularly targeted imaging agents in multiple myeloma (MM). The integrin, very late antigen-4 (VLA4), is differentially expressed in malignant MM cells as well as in the pathogenic inflammatory microenvironmental cells. [ 64 Cu]Cu-CB-TE1A1P-LLP2A (64 Cu-LLP2A) is a VLA4 targeted, high-affinity radiopharmaceutical with promising utility for managing patients diagnosed with MM. Here, we evaluated safety and human radiation dosimetry of 64 Cu-LLP2A for potential use in MM patients. Methods: Single dose [ nat Cu]Cu-LLP2A (Cu-LLP2A) tolerability and toxicity study was performed in CD-1 (Hsd:ICR) male and female mice. 64 Cu-LLP2A was synthesized in accordance with the good manufacturing practice compliant procedures. Three MM and six healthy participants underwent 64 Cu-LLP2A-PET/CT or PET/MR scans up to three time points to help determine tracer biodistribution, pharmacokinetics and radiation dosimetry. Time-activity curves were plotted for each participant. Mean organ absorbed doses and effective doses were calculated using the Organ Level INternal Dose Assessment (OLINDA) software. Tracer bioactivity was evaluated via cell binding assays and metabolites from human blood samples were analyzed with analytical radio-high performance liquid chromatography. When feasible, VLA4 expression was evaluated in the biopsy tissues using 14-color flow cytometry. Results: 150-fold mass excess of the desired imaging dose was tolerated well in male and female CD-1 mice (no observed adverse effect level (NOEL)). Time-activity curves from human imaging data showed rapid tracer clearance from blood via kidneys and bladder. The effective dose of 64 Cu-LLP2A in humans was 0.036 ± 0.006 mSv/MBq, and spleen had the highest organ uptake of 0.142 ± 0.034 mSv/MBq. Among all tissues, the red marrow demonstrated highest residence time. Image quality analysis supports early imaging time (4-5 h post injection of the radiotracer) as optimal. Cell studies showed statistically significant blocking for the tracer produced for all of the human studies (82.42 ± 13.47%). Blood metabolism studies confirmed a stable product peak (> 90%) up to 1 h post-injection of the radiopharmaceutical. No clinical or laboratory adverse events related to 64 Cu-LLP2A were observed in the human participants. Conclusions: 64 Cu-LLP2A exhibited a favorable dosimetry and safety profile for use in humans.
The Journal of Nuclear Medicine, May 1, 2021
Background: The currently available radiopharmaceuticals are not specific for tumor imaging. Purp... more Background: The currently available radiopharmaceuticals are not specific for tumor imaging. Purpose: The present study was conducted to radiolabel doxorubicin with Technetium-99m ([99m]Tc) as a scintigraphic marker of high DNA turnover/intercalation in malignant cells. Methods: Labeling was done by direct method and the developed radiotracer was subjected to quality control tests. The blood kinetics, scintigraphy of tumor-bearing mice, and biodistribution were studied after intravenous injection of about 7.4MBq of [99m]Tc-doxorubicin. The isotime (5 minutes) anterior images were acquired at different time intervals of 1.5, 3, and 4 hours. Results: The labeling efficiency of [99m]Tc-doxorubicin was estimated to be more than 95%. The protein-binding efficiency was greater than 88 % and in vitro stability was up to 24 hours. The biodistribution data support the clearance of the radioligand by dual (renal and hepatic) pathways. A semiquantitative data analysis of the anterior images in...
Additional file1. Supplementary Fig S1: (a) Radio-HPLC chromatogram of [64Cu]Cu-LLP2A showing >... more Additional file1. Supplementary Fig S1: (a) Radio-HPLC chromatogram of [64Cu]Cu-LLP2A showing > 99% of radiolabeled product at the retention time of 5.6 min. (b) UV-visible spectrum showing the LLP2A peak at the same retention time as that of radiolabeled LLP2A. Supplementary Fig S2: Kaplan-Meier survival plots of MM.1S-CG and U266-CG disseminated tumor bearing NOD-SCID Gamma (NSG) mice (treated n=6/group and untreated n=6/group). Supplemtary Fig S3: Representative Images. (a) Region of Interest (ROI) drawn on a whole body of a mouse to determine the BLI signal. (b) ROI drawn on PET/CT slices on the sagittal sections for spine, right and left femur.
The Journal of Nuclear Medicine, May 1, 2020
Dendrimers - Fundamentals and Applications, Apr 25, 2018
Introduction: Angiogenesis is a normal physiological process that plays an imperative role during... more Introduction: Angiogenesis is a normal physiological process that plays an imperative role during tumor development. We believe that the development of a non-invasive imaging technique targeting angiogenesis can provide a better understanding of this important process. Positron emission tomography (PET)-a highly sensitive imaging technique can offer accurate degree of disease quantification. The phenomenon of enhanced permeability and retention effect (EPR effect) is now becoming the gold standard in cancer targeting drug designing. Dendrimers have the ability to exhibit EPR effect for targeted therapeutic/drug delivery approach. Therefore, molecular imaging of tumor angiogenesis using radio-labeled dendrimers is expected to broaden the possibilities for drug development. Body: In the present chapter, the significance of performing conjugation chemistry of bifunctional chelators quality control parameters of the radiolabeled dendrimer conjugates in vitro stability, animal biodistribution, radiation dosimetry and molecular imaging of animal tumor model after injecting radiotracer have also been discussed in detail. Conclusion: Conjugation of the radio-metal complexes to larger molecules like dendrimers has created a new domain of research in the field of biomedical applications. Therefore, it has been proposed to develop new effective targeting moieties suitable for radiolabeling with PET tracers so as to perform molecular imaging studies.
Scientific Reports
Multiple myeloma (MM) is a cancer of bone marrow (BM) plasma cells, which is increasingly treatab... more Multiple myeloma (MM) is a cancer of bone marrow (BM) plasma cells, which is increasingly treatable but still incurable. In 90% of MM patients, severe osteolysis results from pathological interactions between MM cells and the bone microenvironment. Delineating specific molecules and pathways for their role in cancer supportive interactions in the BM is vital for developing new therapies. Very Late Antigen 4 (VLA4, integrin α4β1) is a key player in cell–cell adhesion and signaling between MM and BM cells. We evaluated a VLA4 selective near infrared fluorescent probe, LLP2A-Cy5, for in vitro and in vivo optical imaging of VLA4. Furthermore, two VLA4-null murine 5TGM1 MM cell (KO) clones were generated by CRISPR/Cas9 knockout of the Itga4 (α4) subunit, which induced significant alterations in the transcriptome. In contrast to the VLA4+ 5TGM1 parental cells, C57Bl/KaLwRij immunocompetent syngeneic mice inoculated with the VLA4-null clones showed prolonged survival, reduced medullary dis...
Applied radiation and isotopes: including data, instrumentation and methods for use in agriculture, industry and medicine
The present study describes the optimization of (68)Ga radiolabeling with PAMAM dendrimer-DOTA co... more The present study describes the optimization of (68)Ga radiolabeling with PAMAM dendrimer-DOTA conjugate. A conjugate (PAMAM-DOTA) concentration of 11.69µM, provided best radiolabeling efficiency of more than 93.0% at pH 4.0, incubation time of 30.0min and reaction temperature ranging between 90 and 100°C. The decay corrected radiochemical yield was found to be 79.4±0.01%. The radiolabeled preparation ([(68)Ga]-DOTA-PAMAM-D) remained stable (radiolabeling efficiency of 96.0%) at room temperature and in serum for up to 4-h. The plasma protein binding was observed to be 21.0%. After intravenous administration, 50.0% of the tracer cleared from the blood circulation by 30-min and less than 1.0% of the injected activity remained in blood by 1.0h. The animal biodistribution studies demonstrated that the tracer excretes through the kidneys and about 0.33% of the %ID/g accumulated in the tumor at 1h post injection. The animal organ's biodistribution data was supported by animal PET imag...
![Research paper thumbnail of In vivo quantitative assessment of therapeutic response to bortezomib therapy in disseminated animal models of multiple myeloma with [18F]FDG and [64Cu]Cu-LLP2A PET](https://attachments.academia-assets.com/71421271/thumbnails/1.jpg)
](EJNMMI Research
Background Multiple myeloma (MM) is a disease of cancerous plasma cells in the bone marrow. Imagi... more Background Multiple myeloma (MM) is a disease of cancerous plasma cells in the bone marrow. Imaging-based timely determination of therapeutic response is critical for improving outcomes in MM patients. Very late antigen-4 (VLA4, CD49d/CD29) is overexpressed in MM cells. Here, we evaluated [18F]FDG and VLA4 targeted [64Cu]Cu-LLP2A for quantitative PET imaging in disseminated MM models of variable VLA4 expression, following bortezomib therapy. Methods In vitro and ex vivo VLA4 expression was evaluated by flow cytometry. Human MM cells, MM.1S-CG and U266-CG (C: luciferase and G: green fluorescent protein), were injected intravenously in NOD-SCID gamma mice. Tumor progression was monitored by bioluminescence imaging (BLI). Treatment group received bortezomib (1 mg/kg, twice/week) intraperitoneally. All cohorts (treated, untreated and no tumor) were longitudinally imaged with [18F]FDG (7.4–8.0 MBq) and [64Cu]Cu-LLP2A (2–3 MBq; Molar Activity: 44.14 ± 1.40 MBq/nmol) PET, respectively. Res...
European Journal of Nuclear Medicine and Molecular Imaging
Molecular imaging and biology, Mar 13, 2024
Purpose Multiple myeloma (MM) affects over 35,000 patients each year in the US. There remains a n... more Purpose Multiple myeloma (MM) affects over 35,000 patients each year in the US. There remains a need for versatile Positron Emission Tomography (PET) tracers for the detection, accurate staging, and monitoring of treatment response of MM that have optimal specificity and translational attributes. CD38 is uniformly overexpressed in MM and thus represents an ideal target to develop CD38-targeted small molecule PET radiopharmaceuticals to address these challenges. Procedures Using phage display peptide libraries and pioneering algorithms, we identified novel CD38 specific peptides. Imaging bioconjugates were synthesized using solid phase peptide chemistry, and systematically analyzed in vitro and in vivo in relevant MM systems. The CD38-targeted bioconjugates were radiolabeled with copper-64 ( 64 Cu) with100% radiochemical purity and an average specific activity of 3.3 -6.6 MBq/nmol. The analog NODAGA-PEG4-SL022-GGS (SL022: Thr-His-Tyr-Pro-Ile-Val-Ile) had a K d of 7.55 ± 0.291 nM and was chosen as the lead candidate. 64 Cu-NODAGA-PEG4-SL022-GGS demonstrated high binding affinity to CD38 expressing human myeloma MM.1S-CBR-GFP-WT cells, which was blocked by the nonradiolabeled version of the peptide analog and anti-CD38 clinical antibodies, daratumumab and isatuximab, by 58%, 73%, and 78%, respectively. The CD38 positive MM.1S-CBR-GFP-WT cells had > 68% enhanced cellular binding when compared to MM.1S-CBR-GFP-KO cells devoid of CD38. Furthermore, our new CD38-targeted radiopharmaceutical allowed visualization of tumors located in marrow rich bones, remaining there for up to 4 h. Clearance from non-target organs occurred within 60 min. Quantitative PET data from a murine disseminated tumor model showed significantly higher accumulation in the bones of tumor-bearing animals compared to tumor-naïve animals (SUV max 2.06 ± 0.4 versus 1.24 ± 0.4, P = 0.02). Independently, tumor uptake of the target compound was significantly higher (P = 0.003) compared to the scrambled peptide, 64 Cu-NODAGA-PEG4-SL041-GGS (SL041: Thr-Tyr-His-Ile-Pro-Ile-Val). The subcutaneous MM model demonstrated significantly higher accumulation in tumors compared to muscle at 1 and 4 h after tracer administration (SUV max 0.8 ± 0.2 and 0.14 ± 0.04, P = 0.04 at 1 h; SUV max 0.89 ± 0.01 and 0.09 ± 0.01, P = 0.0002 at 4 h). Conclusions The novel CD38-targeted, radiolabeled bioconjugates were specific and allowed visualization of MM, providing a starting point for the clinical translation of such tracers for the detection of MM.
The American Journal of Gastroenterology, Apr 1, 2013
Research Square (Research Square), Jul 9, 2021
Multiple myeloma (MM) is a disease of cancerous plasma cells. Current treatments have improved th... more Multiple myeloma (MM) is a disease of cancerous plasma cells. Current treatments have improved the survival rate; however, most MM patients relapse. Imaging based timely determination of therapeutic response is critical for improving outcomes in MM patients. Very late antigen-4 (VLA4) is over expressed in MM cells. Here, we evaluated [ 18 F]FDG and VLA4 targeted [ 64 Cu]LLP2A for quantitative PET imaging in MM models of variable VLA4 expression, and following bortezomib therapy. In vitro and ex vivo VLA4 expression was evaluated by ow cytometry. Human MM cells, MM.1S-CG and U266-CG (CG: luciferase and green uorescent protein), were injected intravenously in NOD-SCID gamma mice. Tumor progression was monitored by bioluminescence imaging (BLI). Treatment group received bortezomib (1mg/kg, twice/week) intraperitoneally. All cohorts (treated, untreated and no-tumor) were longitudinally imaged with [ 64 Cu]LLP2A (2-3 MBq; Molar Activity: 44.14±1.40 MBq/nmol) and [ 18 F]FDG (7.4-8.0 MBq) PET respectively. Flow cytometry con rmed high expression of CD49d in U266 cells (>99%) and moderate expression in MM.1S cells (~52%). BLI showed decrease in total body ux in treated mice. In MM.1S-CG untreated versus treated mice, [ 64 Cu]LLP2A localized with a signi cantly higher SUV mean in spine (0.58 versus 0.31) and femur (0.72 versus 0.39) at week 4 post tumor inoculation. In U266-CG treated versus untreated mice, there was a 4-time percent [ 64 Cu]LLP2A increase in spine at week 3. Compared to [ 64 Cu]LLP2A, [ 18 F]FDG PET detected treatment related changes at later time points. [ 64 Cu]LLP2A is a promising tracer for in vivo assessment of therapeutic response in disseminated models of MM.
Photodiagnosis and Photodynamic Therapy, Mar 1, 2023
Photodiagnosis and Photodynamic Therapy
Journal of bone oncology, Apr 1, 2024
The Journal of Nuclear Medicine, Aug 25, 2022
Background: There remains an unmet need for molecularly targeted imaging agents in multiple myelo... more Background: There remains an unmet need for molecularly targeted imaging agents in multiple myeloma (MM). The integrin, very late antigen-4 (VLA4), is differentially expressed in malignant MM cells as well as in the pathogenic inflammatory microenvironmental cells. [ 64 Cu]Cu-CB-TE1A1P-LLP2A (64 Cu-LLP2A) is a VLA4 targeted, high-affinity radiopharmaceutical with promising utility for managing patients diagnosed with MM. Here, we evaluated safety and human radiation dosimetry of 64 Cu-LLP2A for potential use in MM patients. Methods: Single dose [ nat Cu]Cu-LLP2A (Cu-LLP2A) tolerability and toxicity study was performed in CD-1 (Hsd:ICR) male and female mice. 64 Cu-LLP2A was synthesized in accordance with the good manufacturing practice compliant procedures. Three MM and six healthy participants underwent 64 Cu-LLP2A-PET/CT or PET/MR scans up to three time points to help determine tracer biodistribution, pharmacokinetics and radiation dosimetry. Time-activity curves were plotted for each participant. Mean organ absorbed doses and effective doses were calculated using the Organ Level INternal Dose Assessment (OLINDA) software. Tracer bioactivity was evaluated via cell binding assays and metabolites from human blood samples were analyzed with analytical radio-high performance liquid chromatography. When feasible, VLA4 expression was evaluated in the biopsy tissues using 14-color flow cytometry. Results: 150-fold mass excess of the desired imaging dose was tolerated well in male and female CD-1 mice (no observed adverse effect level (NOEL)). Time-activity curves from human imaging data showed rapid tracer clearance from blood via kidneys and bladder. The effective dose of 64 Cu-LLP2A in humans was 0.036 ± 0.006 mSv/MBq, and spleen had the highest organ uptake of 0.142 ± 0.034 mSv/MBq. Among all tissues, the red marrow demonstrated highest residence time. Image quality analysis supports early imaging time (4-5 h post injection of the radiotracer) as optimal. Cell studies showed statistically significant blocking for the tracer produced for all of the human studies (82.42 ± 13.47%). Blood metabolism studies confirmed a stable product peak (> 90%) up to 1 h post-injection of the radiopharmaceutical. No clinical or laboratory adverse events related to 64 Cu-LLP2A were observed in the human participants. Conclusions: 64 Cu-LLP2A exhibited a favorable dosimetry and safety profile for use in humans.
The Journal of Nuclear Medicine, May 1, 2021
Background: The currently available radiopharmaceuticals are not specific for tumor imaging. Purp... more Background: The currently available radiopharmaceuticals are not specific for tumor imaging. Purpose: The present study was conducted to radiolabel doxorubicin with Technetium-99m ([99m]Tc) as a scintigraphic marker of high DNA turnover/intercalation in malignant cells. Methods: Labeling was done by direct method and the developed radiotracer was subjected to quality control tests. The blood kinetics, scintigraphy of tumor-bearing mice, and biodistribution were studied after intravenous injection of about 7.4MBq of [99m]Tc-doxorubicin. The isotime (5 minutes) anterior images were acquired at different time intervals of 1.5, 3, and 4 hours. Results: The labeling efficiency of [99m]Tc-doxorubicin was estimated to be more than 95%. The protein-binding efficiency was greater than 88 % and in vitro stability was up to 24 hours. The biodistribution data support the clearance of the radioligand by dual (renal and hepatic) pathways. A semiquantitative data analysis of the anterior images in...
Additional file1. Supplementary Fig S1: (a) Radio-HPLC chromatogram of [64Cu]Cu-LLP2A showing >... more Additional file1. Supplementary Fig S1: (a) Radio-HPLC chromatogram of [64Cu]Cu-LLP2A showing > 99% of radiolabeled product at the retention time of 5.6 min. (b) UV-visible spectrum showing the LLP2A peak at the same retention time as that of radiolabeled LLP2A. Supplementary Fig S2: Kaplan-Meier survival plots of MM.1S-CG and U266-CG disseminated tumor bearing NOD-SCID Gamma (NSG) mice (treated n=6/group and untreated n=6/group). Supplemtary Fig S3: Representative Images. (a) Region of Interest (ROI) drawn on a whole body of a mouse to determine the BLI signal. (b) ROI drawn on PET/CT slices on the sagittal sections for spine, right and left femur.
The Journal of Nuclear Medicine, May 1, 2020
Dendrimers - Fundamentals and Applications, Apr 25, 2018
Introduction: Angiogenesis is a normal physiological process that plays an imperative role during... more Introduction: Angiogenesis is a normal physiological process that plays an imperative role during tumor development. We believe that the development of a non-invasive imaging technique targeting angiogenesis can provide a better understanding of this important process. Positron emission tomography (PET)-a highly sensitive imaging technique can offer accurate degree of disease quantification. The phenomenon of enhanced permeability and retention effect (EPR effect) is now becoming the gold standard in cancer targeting drug designing. Dendrimers have the ability to exhibit EPR effect for targeted therapeutic/drug delivery approach. Therefore, molecular imaging of tumor angiogenesis using radio-labeled dendrimers is expected to broaden the possibilities for drug development. Body: In the present chapter, the significance of performing conjugation chemistry of bifunctional chelators quality control parameters of the radiolabeled dendrimer conjugates in vitro stability, animal biodistribution, radiation dosimetry and molecular imaging of animal tumor model after injecting radiotracer have also been discussed in detail. Conclusion: Conjugation of the radio-metal complexes to larger molecules like dendrimers has created a new domain of research in the field of biomedical applications. Therefore, it has been proposed to develop new effective targeting moieties suitable for radiolabeling with PET tracers so as to perform molecular imaging studies.
Scientific Reports
Multiple myeloma (MM) is a cancer of bone marrow (BM) plasma cells, which is increasingly treatab... more Multiple myeloma (MM) is a cancer of bone marrow (BM) plasma cells, which is increasingly treatable but still incurable. In 90% of MM patients, severe osteolysis results from pathological interactions between MM cells and the bone microenvironment. Delineating specific molecules and pathways for their role in cancer supportive interactions in the BM is vital for developing new therapies. Very Late Antigen 4 (VLA4, integrin α4β1) is a key player in cell–cell adhesion and signaling between MM and BM cells. We evaluated a VLA4 selective near infrared fluorescent probe, LLP2A-Cy5, for in vitro and in vivo optical imaging of VLA4. Furthermore, two VLA4-null murine 5TGM1 MM cell (KO) clones were generated by CRISPR/Cas9 knockout of the Itga4 (α4) subunit, which induced significant alterations in the transcriptome. In contrast to the VLA4+ 5TGM1 parental cells, C57Bl/KaLwRij immunocompetent syngeneic mice inoculated with the VLA4-null clones showed prolonged survival, reduced medullary dis...
Applied radiation and isotopes: including data, instrumentation and methods for use in agriculture, industry and medicine
The present study describes the optimization of (68)Ga radiolabeling with PAMAM dendrimer-DOTA co... more The present study describes the optimization of (68)Ga radiolabeling with PAMAM dendrimer-DOTA conjugate. A conjugate (PAMAM-DOTA) concentration of 11.69µM, provided best radiolabeling efficiency of more than 93.0% at pH 4.0, incubation time of 30.0min and reaction temperature ranging between 90 and 100°C. The decay corrected radiochemical yield was found to be 79.4±0.01%. The radiolabeled preparation ([(68)Ga]-DOTA-PAMAM-D) remained stable (radiolabeling efficiency of 96.0%) at room temperature and in serum for up to 4-h. The plasma protein binding was observed to be 21.0%. After intravenous administration, 50.0% of the tracer cleared from the blood circulation by 30-min and less than 1.0% of the injected activity remained in blood by 1.0h. The animal biodistribution studies demonstrated that the tracer excretes through the kidneys and about 0.33% of the %ID/g accumulated in the tumor at 1h post injection. The animal organ's biodistribution data was supported by animal PET imag...
EJNMMI Research
Background Multiple myeloma (MM) is a disease of cancerous plasma cells in the bone marrow. Imagi... more Background Multiple myeloma (MM) is a disease of cancerous plasma cells in the bone marrow. Imaging-based timely determination of therapeutic response is critical for improving outcomes in MM patients. Very late antigen-4 (VLA4, CD49d/CD29) is overexpressed in MM cells. Here, we evaluated [18F]FDG and VLA4 targeted [64Cu]Cu-LLP2A for quantitative PET imaging in disseminated MM models of variable VLA4 expression, following bortezomib therapy. Methods In vitro and ex vivo VLA4 expression was evaluated by flow cytometry. Human MM cells, MM.1S-CG and U266-CG (C: luciferase and G: green fluorescent protein), were injected intravenously in NOD-SCID gamma mice. Tumor progression was monitored by bioluminescence imaging (BLI). Treatment group received bortezomib (1 mg/kg, twice/week) intraperitoneally. All cohorts (treated, untreated and no tumor) were longitudinally imaged with [18F]FDG (7.4–8.0 MBq) and [64Cu]Cu-LLP2A (2–3 MBq; Molar Activity: 44.14 ± 1.40 MBq/nmol) PET, respectively. Res...
European Journal of Nuclear Medicine and Molecular Imaging