Prostate-specific membrane antigens (PSMAs) are frequently overexpressed in both tumor stromal endothelial cells and malignant cells (stromal/tumor cells) of various cancers. The RGD (Arg-Gly-Asp) ...peptide sequence can specifically detect integrins involved in tumor angiogenesis. This study aimed to preclinically evaluate the cytotoxicity, biokinetics, dosimetry, and therapeutic efficacy of
Ac-iPSMA-RGD to determine its potential as an improved radiopharmaceutical for alpha therapy compared with the
Ac-iPSMA and
Ac-RGD monomers. HEHA-HYNIC-iPSMA-RGD (iPSMA-RGD) was synthesized and characterized by FT-IR, UV-vis, and UPLC mass spectroscopy. The cytotoxicity of
Ac-iPSMA-RGD was assessed in HCT116 colorectal cancer cells. Biodistribution, biokinetics, and therapeutic efficacy were evaluated in nude mice with induced HCT116 tumors. In vitro results showed increased DNA double-strand breaks through ROS generation, cell apoptosis, and death in HCT116 cells treated with
Ac-iPSMA-RGD. The results also demonstrated in vivo cytotoxicity in cancer cells after treatment with
Ac-iPSMA-RGD and biokinetic and dosimetric properties suitable for alpha therapy, delivering ablative radiation doses up to 237 Gy/3.7 kBq to HCT116 tumors in mice. Given the phenotype of HCT116 cancer cells, the results of this study warrant further dosimetric and clinical studies to determine the potential of
Ac-iPSMA-RGD in the treatment of colorectal cancer.
Current cancer therapies focus on reducing immunosuppression and remodeling the tumor microenvironment to inhibit metastasis, cancer progression, and therapeutic resistance. Programmed death receptor ...1 (PD-1) is expressed on immune T cells and is one of the so-called checkpoint proteins that can suppress or stop the immune response. To evade the immune system, cancer cells overexpress a PD-1 inhibitor protein (PD-L1), which binds to the surface of T cells to activate signaling pathways that induce immune suppression. This research aimed to synthesize PD-L1 inhibitory peptides (PD-L1-i) labeled with lutetium-177 (
Lu-DOTA-PD-L1-i) and actinium-225 (
Ac-HEHA-PD-L1-i) and to preclinically evaluate their potential as radiopharmaceuticals for targeted radiotherapy at the tumor microenvironment level. Using PD-L1-i peptide as starting material, conjugation with HEHA-benzene-SCN and DOTA-benzene-SCN was performed to yield DOTA-PD-L1-i and HEHA-PD-L1-I, which were characterized by FT-IR, UV-vis spectroscopy, and HPLC. After labeling the conjugates with
Ac and
Lu, cellular uptake in HCC827 cancer cells (PD-L1 positive), conjugate specificity evaluation by immunofluorescence, radiotracer effect on cell viability, biodistribution, biokinetics, and assessment of radiation absorbed dose in mice with in duced lung micrometastases were performed.
Ac-HEHA-PD-L1-i and
Lu-DOTA-PD-L1-i, obtained with radiochemical purities of 95 ± 3% and 98.5 ± 0.5%, respectively, showed in vitro and in vivo specific recognition for the PD-L1 protein in lung cancer cells and high uptake in HCC287 lung micrometastases (>30% ID). The biokinetic profiles of
Lu-DOTA-PD-L1-i and
Ac-DOTA-PD-L1-i showed rapid blood clearance with renal and hepatobiliary elimination and no accumulation in normal tissues.
Ac-DOTA-PD-L1-i produced a radiation dose of 5.15 mGy/MBq to lung micrometastases. In the case of
Lu-DOTA-PD-L1-i, the radiation dose delivered to the lung micrometastases was ten times (43 mGy/MBq) that delivered to the kidneys (4.20 mGy/MBq) and fifty times that delivered to the liver (0.85 mGy/MBq). Therefore, the radiotherapeutic PD-L1-i ligands of
Ac and
Lu developed in this research could be combined with immunotherapy to enhance the therapeutic effect in various types of cancer.
This research aimed to prepare .sup.99mTc-/.sup.177Lu-CXCR4-L radiotracers and evaluate their in vitro and in vivo capability to detect the chemokine-4 receptor. Molecular docking calculations, ...K.sub.d values ( 98.5%) estimated by saturation binding assays, as well as biodistribution studies in mice with induced tumors, confirmed the affinity of radiotracers towards CXCR4, expressed in DU-4475 breast cancer cells and C6 glioblastoma cells. Micro-SPECT/CT images showed that .sup.99mTc-CXCR4-L and .sup.177Lu-CXCR4-L could work as a theranostic pair for CXCR4 targets. Results warrant additional research to assess the therapeutic efficacy and dosimetry of .sup.177Lu-CXCR4-L.
Recently, we reported a new fibroblast activation protein (FAP) inhibitor radiopharmaceutical based on the
Tc-((R)-1-((6-hydrazinylnicotinoyl)-D-alanyl) pyrrolidin-2-yl) boronic acid (
...Tc-HYNIC-D-Alanine-BoroPro)(
Tc-HYNIC-iFAP) structure for tumor microenvironment SPECT imaging. This research aimed to synthesize
Ga-2,2',2″,2‴-(2-(4-(2-(5-(((S)-1-((S)-2-boronopyrrolidin-1-yl)-1-oxopropan-2-yl)carbamoyl)pyridin-2-yl)hydrazine-1-carbothioamido)benzyl)-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrayl)tetraacetic acid (
Ga-DOTA-D-Alanine-BoroPro)(
Ga-iFAP) as a novel radiotracer for PET imaging and evaluate its usefulness for FAP expression in malignant and non-malignant tissues. The coupling of p-SCN-benzene DOTA with HYNIC-iFAP was used for the chemical synthesis and further labeling with
Ga. Radiochemical purity was verified by radio-HPLC. The specificity of
Ga-iFAP was evaluated in HCT116 cells, in which FAP expression was verified by immunofluorescence and Western blot. Biodistribution and biokinetic studies were performed in murine models.
Ga-iFAP uptake at the myocardial level was assessed in mice with induced infarction. First-in-human images of
Ga-iFAP in healthy subjects and patients with myocardial infarction, glioblastoma, prostate cancer, and breast cancer were also obtained. DOTA-D-Alanine BoroPro was prepared with a chemical purity of 98% and was characterized by UPLC mass spectroscopy, FT-IR, and UV-vis. The
Ga-iFAP was obtained with a radiochemical purity of >95%. In vitro and in vivo studies demonstrated
Ga-iFAP-specific recognition for FAP, rapid renal elimination, and adequate visualization of the glioblastoma, breast tumor, prostate cancer, and myocardial infarction sites. The results of this research justify further dosimetry and clinical trials to establish the specificity and sensitivity of
Ga-iFAP PET for FAP expression imaging.
Recently, we reported a new fibroblast activation protein (FAP) inhibitor radiopharmaceutical based on the sup.99mTc-((R)-1-((6-hydrazinylnicotinoyl)-D-alanyl) pyrrolidin-2-yl) boronic acid ...(sup.99mTc-HYNIC-D-Alanine-BoroPro)(sup.99mTc-HYNIC-iFAP) structure for tumor microenvironment SPECT imaging. This research aimed to synthesize sup.68Ga-2,2′,2″,2‴-(2-(4-(2-(5-(((S)-1-((S)-2-boronopyrrolidin-1-yl)-1-oxopropan-2-yl)carbamoyl)pyridin-2-yl)hydrazine-1-carbothioamido)benzyl)-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrayl)tetraacetic acid (sup.68Ga-DOTA-D-Alanine-BoroPro)(sup.68Ga-iFAP) as a novel radiotracer for PET imaging and evaluate its usefulness for FAP expression in malignant and non-malignant tissues. The coupling of p-SCN-benzene DOTA with HYNIC-iFAP was used for the chemical synthesis and further labeling with sup.68Ga. Radiochemical purity was verified by radio-HPLC. The specificity of sup.68Ga-iFAP was evaluated in HCT116 cells, in which FAP expression was verified by immunofluorescence and Western blot. Biodistribution and biokinetic studies were performed in murine models. sup.68Ga-iFAP uptake at the myocardial level was assessed in mice with induced infarction. First-in-human images of sup.68Ga-iFAP in healthy subjects and patients with myocardial infarction, glioblastoma, prostate cancer, and breast cancer were also obtained. DOTA-D-Alanine BoroPro was prepared with a chemical purity of 98% and was characterized by UPLC mass spectroscopy, FT-IR, and UV-vis. The sup.68Ga-iFAP was obtained with a radiochemical purity of >95%. In vitro and in vivo studies demonstrated sup.68Ga-iFAP-specific recognition for FAP, rapid renal elimination, and adequate visualization of the glioblastoma, breast tumor, prostate cancer, and myocardial infarction sites. The results of this research justify further dosimetry and clinical trials to establish the specificity and sensitivity of sup.68Ga-iFAP PET for FAP expression imaging.
Prostate-specific membrane antigen (PSMA) is expressed in a variety of cancer cells, while the fibroblast activation protein (FAP) is expressed in the microenvironment of tumors. Previously, we ...reported the ability of iPSMA and iFAP ligands to specifically target PSMA and FAP proteins, as well as the preparation of stable 177Lu2O3 nanoparticles (<100 nm) functionalized with target-specific peptides. This research aimed to evaluate the dosimetry and therapeutic response of Lu2O3-iPSMA and Lu2O3-iFAP nanoparticles activated by neutron irradiation to demonstrate their potential for theranostic applications in nuclear medicine. The biokinetic behavior, radiation absorbed dose, and metabolic activity (18FFDG/micro-PET, SUV) in preclinical tumor tissues (athymic mice), following treatment with 177Lu2O3-iPSMA, 177Lu2O3-iFAP or 177Lu2O3 nanoparticles, were assessed. One patient with multiple colorectal liver metastases (PSMA-positive) received 177Lu2O3-iPSMA under a “compassionate use” protocol. Results indicated no significant difference (p < 0.05) between 177Lu2O3-iPSMA and 177Lu2O3-iFAP, regarding tumor radiation absorbed doses (105 ± 14 Gy, 99 ± 12 Gy and 58 ± 7 Gy for 177Lu2O3-iPSMA, 177Lu2O3-iFAP, and 177Lu2O3, respectively) and tumor metabolic activity (SUV of 0.421 ± 0.092, 0.375 ± 0.104 and 1.821 ± 0.891 for 177Lu2O3-iPSMA, 177Lu2O3-iFAP, and 177Lu2O3, respectively) in mice after treatment, which correlated with the observed therapeutic response. 177Lu2O3-iPSMA and 177Lu2O3-iFAP significantly inhibited tumor progression, due to the prolonged tumor retention and a combination of 177Lu radiotherapy and iPSMA or iFAP molecular recognition. There were negligible uptake values in non-target tissues and no evidence of liver and renal toxicity. The doses received by the patient’s liver metastases (42−210 Gy) demonstrated the potential of 177Lu2O3-iPSMA for treating colorectal liver metastases.
This research aimed to assess the radiation absorbed dose produced by 177Lu-iPSMA (177Lu-prostate specific membrane antigen inhibitor), 225Ac-iPSMA and 223RaCl2 to prostate cancer cell nuclei in a ...simplified model of bone by using an experimental in-vitro prostate cancer LNCaP cell biokinetic study and Monte Carlo simulation with the MCNPX code. Results showed that 225Ac-iPSMA releases a nine hundred-fold radiation dose greater than 177Lu-iPSMA and 14 times more than 223RaCl2 per unit of activity retained in bone. 225Ac-iPSMA could be the best option for treatment of bone metastases in prostate cancer.
•225Ac-iPSMA produces doses to prostate cancer cells almost 3 orders of magnitude greater than 177Lu-iPSMA.•225Ac-iPSMA produces doses to prostate cancer cells in bone metastases 14 times greater than 223RaCl2.•225Ac-iPSMA could the best option for treatment of bone metastases in prostate cancer.
Background: Prostate-specific membrane antigen (PSMA) is highly over-expressed in advanced prostate cancers. 68Ga-labeled PSMA inhibitors (iPSMA) are currently used for prostate cancer detection by ...PET imaging. The availability of simple, efficient and reproducible radiolabeling procedures is essential for developing new SPECT radiopharmaceuticals for clinical translation. The aim of this research was to prepare 99mTc-EDDA/HYNIC-Lys(Nal)-Urea-Glu (99mTc-EDDA/HYNIC-iPSMA) obtained from lyophilized kit formulations and evaluate the in vitro and in vivo radiopharmaceutical binding to prostate cancer cells over-expressing PSMA, as well as the 99mTc-EDDA/HYNIC-iPSMA normal biodistribution in humans and the preliminary uptake in patients with prostate cancer. Methods: 99mTc labeling was performed by adding sodium pertechnetate solution and a 0.2 M phosphate buffer (pH 7.0) to a lyophilized formulation containing HYNIC-iPSMA, EDDA, tricine, mannitol and stannous chloride. The radiochemical purity was evaluated by reversed-phase HPLC and ITLC-SG analyses. Stability studies in human serum were performed by size-exclusion HPLC. In vitro cell uptake was tested using prostate cancer cells (LNCaP) with blocked and non-blocked receptors. Biodistribution and tumor uptake were determined in LNCaP tumor-bearing nude mice with blocked and non-blocked receptors, and images were obtained using a micro-SPECT/CT. Whole-body images from three healthy men and two patients with histologically-confirmed prostate cancer (one of them with a previous 68Ga-PSMA-617scan) were acquired at 1 h and 3 h after 99mTc-EDDA/HYNIC-iPSMA administration with radiochemical purities of >98%. Results: In vitro and in vivo studies showed high radiopharmaceutical stability in human serum, specific recognition for PSMA, high tumor uptake (10.22 ± 2.96% ID/g at 1 h) with rapid blood clearance and mainly kidney elimination. Preliminary images in patients demonstrated the ability of 99mTc-EDDA/HYNIC-iPSMA to detect tumors and metastases of prostate cancer as well as 68Ga-PSMA-617 does. Conclusions: The results obtained in this study warrant further dosimetry and clinical studies to determine the specificity and sensitivity of 99mTc-EDDA/HYNIC-iPSMA.
This research aimed to evaluate the photothermal and radiotherapeutic effect of the
177
Lu–Au-RGD-NLS-Aptamer anti-angiogenic nanosystem on the viability of U87MG cancer cells by using in vitro and ...in vivo models, as well as to assess the synergic effect of both therapies. In vitro results demonstrated a decrease in cell viability to 2.14 ± 0.27% after the treatment with photothermal therapy plus radiotherapy. These results correlated with the observed in vivo therapeutic response in mice with U87MG-induced tumors, in which
177
Lu–Au-RGD-NLS-Aptamer under laser irradiation inhibited tumor progression. The combination of radiotherapy and thermotherapy in one nanoradiopharmaceutical could be potentially useful for cancer treatment.
Abstract Background Prostate-specific membrane antigen (PSMA) is highly over-expressed in advanced prostate cancers.68 Ga-labeled PSMA inhibitors (iPSMA) are currently used for prostate cancer ...detection by PET imaging. The availability of simple, efficient and reproducible radiolabeling procedures is essential for developing new SPECT radiopharmaceuticals for clinical translation. The aim of this research was to prepare99m Tc-EDDA/HYNIC-Lys(Nal)-Urea-Glu (99m Tc-EDDA/HYNIC-iPSMA) obtained from lyophilized kit formulations and evaluate the in vitro and in vivo radiopharmaceutical binding to prostate cancer cells over-expressing PSMA, as well as the99m Tc-EDDA/HYNIC-iPSMA normal biodistribution in humans and the preliminary uptake in patients with prostate cancer. Methods99m Tc labeling was performed by adding sodium pertechnetate solution and a 0.2 M phosphate buffer (pH 7.0) to a lyophilized formulation containing HYNIC-iPSMA, EDDA, tricine, mannitol and stannous chloride. The radiochemical purity was evaluated by reversed-phase HPLC and ITLC-SG analyses. Stability studies in human serum were performed by size-exclusion HPLC. In vitro cell uptake was tested using prostate cancer cells (LNCaP) with blocked and non-blocked receptors. Biodistribution and tumor uptake were determined in LNCaP tumor-bearing nude mice with blocked and non-blocked receptors, and images were obtained using a micro-SPECT/CT. Whole-body images from three healthy men and two patients with histologically-confirmed prostate cancer (one of them with a previous68 Ga-PSMA-617scan) were acquired at 1 h and 3 h after99m Tc-EDDA/HYNIC-iPSMA administration with radiochemical purities of >98%. Results In vitro and in vivo studies showed high radiopharmaceutical stability in human serum, specific recognition for PSMA, high tumor uptake (10.22 ± 2.96% ID/g at 1 h) with rapid blood clearance and mainly kidney elimination. Preliminary images in patients demonstrated the ability of99m Tc-EDDA/HYNIC-iPSMA to detect tumors and metastases of prostate cancer as well as68 Ga-PSMA-617 does. Conclusions The results obtained in this study warrant further dosimetry and clinical studies to determine the specificity and sensitivity of99m Tc-EDDA/HYNIC-iPSMA.
