scholarly journals In vitro and in vivo comparative study of a novel 68Ga-labeled PSMA-targeted inhibitor and 68Ga-PSMA-11

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Huanyu Chen ◽  
Ping Cai ◽  
Yue Feng ◽  
Zhanliang Sun ◽  
Yinwen Wang ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Comparative Study ◽  
Specific Antigen ◽  
In Vivo Studies ◽  
Detection Rates ◽  
High Affinity ◽  
Positron Emission ◽  
Group Target

Abstract68Ga-radiolabeled small molecules that specifically target prostate-specific membrane antigen (PSMA) have been extensively investigated, and some of these tracers have been used in the diagnosis of prostate cancer via 68Ga-positron emission tomography (68Ga-PET). Nevertheless, current 68Ga-labeled radiotracers show only fair detection rates for metastatic prostate cancer lesions, especially those with lower levels of prostate specific antigen (PSA), which often occurs in the biochemical recurrence of prostate cancer. The goal of this study was to design and synthesize a new PSMA-targeted radiotracer, 68Ga-SC691, with high affinity for prostate cancer cells and excellent pharmacokinetics. To this end, structural optimization was carried out on the bifunctional group, target motif, and linker while the high affinity targeting scaffold remained. To explore its potential in the clinic, a comparative study was further performed in vitro and in vivo between 68Ga-SC691 and 68Ga-PSMA-11, a clinically approved tracer for PSMA-positive prostate cancer. SC691 was radiolabeled to provide 68Ga-SC691 in 99% radiolabeling yield under mild conditions. High uptake and a high internalization ratio into LNCaP cells were observed in in vitro studies. In vivo studies showed that 68Ga-SC691 had favorable biodistribution properties and could specifically accumulate on PSMA-positive LNCaP xenografts visualized by micro-PET/CT. This radiotracer showed excellent PET imaging quality and comparable, if not higher, uptake in LNCaP xenografts than 68Ga-PSMA-11.

scholarly journals In Vitro and in Vivo Comparative Study of a Novel 68 Ga-Labeled PSMA-Targeted Inhibitor and 68 Ga -PSMA-11

2021 ◽  
Author(s):  
Huanyu Chen ◽  
Ping Cai ◽  
Yue Feng ◽  
Zhanliang Sun ◽  
Yinwen Wang ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Comparative Study ◽  
Specific Antigen ◽  
In Vivo Studies ◽  
Detection Rates ◽  
High Affinity ◽  
Positron Emission ◽  
Group Target

Abstract 68Ga-radiolabeled small molecules that specifically target prostate specific membrane antigen (PSMA) has been extensively investigated, and some of those tracers have been used in diagnosis of prostate cancer with 68Ga-positron emission tomography (68Ga-PET). Nevertheless, current 68Ga-labeled radiotracers show fair detection rates to metastasized prostate cancer lesions, especially to those with lower level of prostate specific antigen (PSA), which often occur in biochemical recurrence of prostate cancer. The goal of this study was to design and synthesize a new PSMA-targeted radiotracer 68Ga-SC691 with high affinity to prostate cancer cells and excellent pharmacokinetics. To this end, structural optimum was made on the bifunctional group, target motif, and linker while high affinity targeting scaffold was remained. In order to explore its potential in clinical, a comparative study was further performed in vitro and in vivo between 68Ga-SC691 and 68Ga-PSMA-11, the clinically approved tracer for PSMA-positive prostate cancer. SC691 was radiolabeled to provide 68Ga-SC691 in 99% radiolabeling yield under mild conditions. High uptake and internalization ratio into LNCaP cells were observed in in vitro studies. In vivo studies showed that 68Ga-SC691 had a favorable biodistribution property and can specifically accumulate on PSMA-positive LNCaP xenografts visualized by micro-PET/CT. This radiotracer showed excellent PET imaging quality and comparable uptake at LNCaP xenografts if not higher than 68Ga-PSMA-11.

scholarly journals Design of PSMA ligands with modifications at the inhibitor part: an approach to reduce the salivary gland uptake of radiolabeled PSMA inhibitors?

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Veronika Barbara Felber ◽  
Manuel Amando Valentin ◽  
Hans-Jürgen Wester
Keyword(s):  
Salivary Gland ◽  
Solid Phase ◽  
Solid Phase Peptide Synthesis ◽  
In Vivo Studies ◽  
Tumor Xenograft ◽  
Tumor Uptake ◽  
Lncap Cells ◽  
High Affinity

Abstract Aim To investigate whether modifications of prostate-specific membrane antigen (PSMA)-targeted radiolabeled urea-based inhibitors could reduce salivary gland uptake and thus improve tumor-to-salivary gland ratios, several analogs of a high affinity PSMA ligand were synthesized and evaluated in in vitro and in vivo studies. Methods Binding motifs were synthesized ‘on-resin’ or, when not practicable, in solution. Peptide chain elongations were performed according to optimized standard protocols via solid-phase peptide synthesis. In vitro experiments were performed using PSMA+ LNCaP cells. In vivo studies as well as μSPECT/CT scans were conducted with male LNCaP tumor xenograft-bearing CB17-SCID mice. Results PSMA ligands with A) modifications within the central Zn2+-binding unit, B) proinhibitor motifs and C) substituents & bioisosteres of the P1′-γ-carboxylic acid were synthesized and evaluated. Modifications within the central Zn2+-binding unit of PSMA-10 (Glu-urea-Glu) provided three compounds. Thereof, only natLu-carbamate I (natLu-3) exhibited high affinity (IC50 = 7.1 ± 0.7 nM), but low tumor uptake (5.31 ± 0.94% ID/g, 1 h p.i. and 1.20 ± 0.55% ID/g, 24 h p.i.). All proinhibitor motif-based ligands (three in total) exhibited low binding affinities (> 1 μM), no notable internalization and very low tumor uptake (< 0.50% ID/g). In addition, four compounds with P1′-ɣ-carboxylate substituents were developed and evaluated. Thereof, only tetrazole derivative natLu-11 revealed high affinity (IC50 = 16.4 ± 3.8 nM), but also this inhibitor showed low tumor uptake (3.40 ± 0.63% ID/g, 1 h p.i. and 0.68 ± 0.16% ID/g, 24 h p.i.). Salivary gland uptake in mice remained at an equally low level for all compounds (between 0.02 ± 0.00% ID/g and 0.09 ± 0.03% ID/g), wherefore apparent tumor-to-submandibular gland and tumor-to-parotid gland ratios for the modified peptides were distinctly lower (factor 8–45) than for [177Lu]Lu-PSMA-10 at 24 h p.i. Conclusions The investigated compounds could not compete with the in vivo characteristics of the EuE-based PSMA inhibitor [177Lu]Lu-PSMA-10. Although two derivatives (3 and 11) were found to exhibit high affinities towards LNCaP cells, tumor uptake at 24 h p.i. was considerably low, while uptake in salivary glands remained unaffected. Optimization of the established animal model should be envisaged to enable a clear identification of PSMA-targeting radioligands with improved tumor-to-salivary gland ratios in future studies.

scholarly journals Development of a Phototoxicity Testing Strategy for Accurate Photosafety Evaluation of Pharmaceuticals Based on the Assessment of Possible Melanin-Binding Effects

2018 ◽  
Vol 37 (4) ◽  
pp. 296-307
Author(s):  
Jelle Reinen ◽  
Pieter van Sas ◽  
Ton van Huygevoort ◽  
Leticia Rubio ◽  
Kevin Scase ◽  
...  
Keyword(s):  
Cellular Damage ◽  
In Vivo Studies ◽  
Brown Norway ◽  
Albino Rats ◽  
Guidance Document ◽  
High Affinity ◽  
Drug Concentrations ◽  
Melanin Binding

Drug-induced phototoxicity occurs when drugs absorb natural sunlight, leading to chemical reactions causing cellular damage. Distribution to light-exposed tissues is critical and is enhanced by binding to melanin. The International Council on Harmonization S10 guidance document on photosafety evaluation of pharmaceuticals states that although nonpigmented skin tends to be more sensitive than pigmented skin, pigmented skin models should be considered for drugs that bind significantly to melanin. In this study, an in vitro melanin-binding assay was evaluated as prescreening tool for animal model selection. Binding of various structurally diverse phototoxic drugs to synthetic melanin was investigated in vitro and the high-affinity binder sparfloxacin (SPX), moderate-affinity binder 8-methoxypsoralen (8-MOP), and low-affinity binder pirfenidone (PIF) were selected for in vivo studies. Pigmented Brown Norway (BN) rats were compared with nonpigmented Wistar Albino rats to evaluate their sensitivity for the assessment of phototoxicity and skin concentrations of the drugs were measured. For SPX, the onset of phototoxic symptoms was faster for BN rats and drug concentrations were significantly higher in skin of BN rats. For 8-MOP, both models showed comparable sensitivity and skin concentrations did not differ. For the low-affinity binder PIF, no phototoxic effects were observed and skin concentrations in both models were similar. A combined in vitro/in vivo approach was developed that can be applied for accurate photosafety evaluation of pharmaceuticals based on the assessment of possible melanin-binding effects. In view of the presented data, the pigmented model could be considered for compounds showing a high-affinity binding capacity in vitro.

scholarly journals Vitamin D and prostate cancer

2013 ◽  
Vol 66 (5-6) ◽  
pp. 259-262
Author(s):  
Goran Marusic ◽  
Dimitrije Jeremic ◽  
Sasa Vojinov ◽  
Natasa Filipovic ◽  
Milan Popov
Keyword(s):  
Prostate Cancer ◽  
Vitamin D ◽  
Physiological Role ◽  
In Vivo Studies ◽  
Vitamin D Metabolism ◽  
Genetic Changes ◽  
Metabolic Role

In addition to the metabolic role of vitamin D, which is well known and clearly defined, there have been many hypotheses regarding its anti-proliferative and pro-apoptotic role. Epidemiology and Significance of Prostate Cancer. Prostate cancer is the second most common malignancy in men. Long period of cancerogenesis, available tumor markers and high incidence make this cancer ideal for preventive measures. Physiological Role of Vitamin D and its Effect on Prostate Cancer Cells. In vitro and in vivo studies have shown the anti-proliferative and pro-apoptopic role of vitamin D. Disorders of vitamin D metabolism are noted in vitamin D gene level, vitamin D receptor, vitamin D responsive elements and androgen receptors. We present the most important effect of those changes on vitamin D metabolism. Conclusion. Available studies on vitamin D level in serum, prostate tissue, observed activity of vitamin D enzymes and genetic changes give us only a slight insight into the basic mechanisms of vitamin D action in the development of prostate cancer; therefore, further investigations are needed.

scholarly journals A Review of the Potential of Phytochemicals from Prunus africana (Hook f.) Kalkman Stem Bark for Chemoprevention and Chemotherapy of Prostate Cancer

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Richard Komakech ◽  
Youngmin Kang ◽  
Jun-Hwan Lee ◽  
Francis Omujal
Keyword(s):  
Prostate Cancer ◽  
Cancer Cells ◽  
Treatment Options ◽  
Chemotherapeutic Agents ◽  
Sub Saharan Africa ◽  
In Vivo Studies ◽  
Prostate Cancer Cells ◽  
Prunus Africana

Prostate cancer remains one of the major causes of death worldwide. In view of the limited treatment options for patients with prostate cancer, preventive and treatment approaches based on natural compounds can play an integral role in tackling this disease. Recent evidence supports the beneficial effects of plant-derived phytochemicals as chemopreventive and chemotherapeutic agents for various cancers, including prostate cancer. Prunus africana has been used for generations in African traditional medicine to treat prostate cancer. This review examined the potential roles of the phytochemicals from P. africana, an endangered, sub-Saharan Africa plant in the chemoprevention and chemotherapy of prostate cancer. In vitro and in vivo studies have provided strong pharmacological evidence for antiprostate cancer activities of P. africana-derived phytochemicals. Through synergistic interactions between different effective phytochemicals, P. africana extracts have been shown to exhibit very strong antiandrogenic and antiangiogenic activities and have the ability to kill tumor cells via apoptotic pathways, prevent the proliferation of prostate cancer cells, and alter the signaling pathways required for the maintenance of prostate cancer cells. However, further preclinical and clinical studies ought to be done to advance and eventually use these promising phytochemicals for the prevention and chemotherapy of human prostate cancer.

Effect of cabazitaxel on the growth of human castration-refractory prostate cancer cells in vitro compared to docetaxel and on the anti-tumor properties of the angio-inhibitor PEDF in vivo.

2015 ◽  
Vol 33 (7_suppl) ◽  
pp. 205-205
Author(s):  
Thomas Nelius ◽  
Courtney Jarvis ◽  
Dalia Martinez-Marin ◽  
Stephanie Filleur
Keyword(s):  
Prostate Cancer ◽  
Cell Proliferation ◽  
Tumor Growth ◽  
Tumor Cells ◽  
Cell Lines ◽  
In Vitro Cytotoxicity ◽  
In Vivo Studies ◽  
Raw264.7 Macrophages

205 Background: Docetaxel/DTX and cabazitaxel/CBZ have shown promise in the treatment of metastatic Castration-Refractory Prostate Cancer/mCPRC however, comparative studies are missing. Toxicities of these drugs are significant, urging the need to modify taxane regimens. Recently, low-dose metronomic/LDM treatments using conventional chemotherapeutic drugs have shown benefits in CPRC in improving the effect of anti-angiogenic agents. Previously, we have demonstrated that LDM-DTX in combination with PEDF curbs significantly CRPC growth, limits metastases formation and prolongs survival in vivo. In this study, we intended to compare the cytotoxic effect of CBZ and DTX on CRPC cells in vitro and CL1 tumors in vivo. Methods: PC3, DU145 cell lines were from ATCC.CL1 cells were obtained from androgen-deprived LNCaP cells. Cell proliferation was assessed by crystal violet staining and cell cycle analyses. In vitro cytotoxicity assays were performed on CL1 cells/RAW264.7 macrophages co-cultures treated with PEDF and increasing doses of taxanes. For the in vivo studies, CL1 cells were engineered to stably express the DsRed Express protein +/- PEDF. PEDF anti-tumor effects were assessed on s.c. xenografts treated with DTX (5mg/kg ip ev. 4 day) as reference, CBZ (5mg/kg ip ev. 4 days, 1mg/kg for 10 days, 0.5mg/kg q.a.d. and 0.1mg/kg daily) or placebo. Results: CBZ limits cell proliferation with a greater efficacy than DTX in all CRPC cell lines tested. DU145 presented the largest difference. High doses of taxane blocked tumor cells in mitosis, whereas LDM increased the SubG1 population. This effect was significantly higher in DU145 cells treated with CBZ. In vivo, 5mg/kg CBZ delayed tumor growth more efficiently than 5mg/kg DTX. PEDF/5mg/kg CBZ markedly delayed tumor growth compared to all treatments. Finally, engulfment of tumor cells by macrophages was higher in combined treatments suggesting an inflammation-related process. Conclusions: CBZ is more efficient than DTX both in vitro and in vivo.The data also reinforce PEDF as a promising anti-neoplasic agent in combination with LDM taxane chemotherapies.

Preclinical investigation of a small molecule inhibitor of p300/CBP reveals efficacy in patient-derived prostate tumor explants.

2019 ◽  
Vol 37 (15_suppl) ◽  
pp. e16534-e16534 ◽  
Author(s):  
Lisa Butler ◽  
Swati Irani ◽  
Margaret Centenera ◽  
Natalie Ryan ◽  
Neil Pegg ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Cancer Cells ◽  
Small Molecule ◽  
Single Agent ◽  
Specific Antigen ◽  
Resistance Mechanisms ◽  
Prostate Cancer Cells ◽  
In Vivo Models

e16534 Background: Growth and survival of prostate cancer cells are initially dependent upon androgens, and androgen deprivation therapy (ADT) is used to control tumor growth. Unfortunately, resistance to ADT inevitably occurs, and patients relapse with lethal castrate-resistant prostate cancer (CRPC). Increased expression of the androgen receptor (AR) and constitutively active AR variants are hallmarks of CRPC, and treatments targeting aberrant AR signaling are urgently required. CCS1477 is an inhibitor of p300/CBP currently in a Phase I/IIa study for CRPC. CCS1477 enhances degradation of numerous cellular proteins including the AR and AR variants in prostate cancer cells. Our preclinical studies with this compound demonstrated potent single-agent efficacy of CCS1477 using in vitro and in vivo models of prostate cancer and, when used in combination, CCS1477 enhances the efficacy of enzalutamide, a clinical AR antagonist. Understanding the response of clinical tumors to CCS1477, and their potential adaptive evolution, is essential to personalize treatment and predict potential resistance mechanisms. Methods: To assess CCS1477 in human disease, we used a unique model in which clinical prostate tumors from radical prostatectomy are cultured as explants with maintenance of tissue integrity, cell proliferation and androgen signaling. Tumors from 13 patients were cultured in the absence or presence of CCS1477 (10µM) or enzalutamide (10µM) for 48 or 72 hours; micromolar doses were selected to account for altered small molecule uptake and penetration into tissues compared to cell lines, as previously reported. Proliferation, apoptosis and androgen signaling were all analyzed post-culture. Results: Whereas the tumor explants exhibited highly heterogenous proliferative responses to enzalutamide, tumors from all patients exhibited a marked antiproliferative response to CCS1477 (mean reduction in Ki67 immunoreactivity of > 90% compared to vehicle control; p < 0.0005). Culture with CCS1477 was associated with repression of androgen signaling in the prostate tissues, measured by expression and secretion of the clinical biomarker prostate specific antigen (PSA). Conclusions: The consistent and pronounced efficacy of CCS1477 in this patient-derived model would support further investigation of this class of epigenetic agents in the castrate-sensitive prostate cancer setting.

scholarly journals Extracellular Vesicles in Prostate Cancer: New Future Clinical Strategies?

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Ilaria Giusti ◽  
Vincenza Dolo
Keyword(s):  
Prostate Cancer ◽  
Extracellular Vesicles ◽  
Specific Antigen ◽  
Specific Marker ◽  
Cellular Origin ◽  
Organ Specific ◽  
Potential Use

Prostate cancer (PCa) is the most common cancer—excluding skin tumors—in men older than 50 years of age. Over time, the ability to diagnose PCa has improved considerably, mainly due to the introduction of prostate-specific antigen (PSA) in the clinical routine. However, it is important to take into account that although PSA is a highly organ-specific marker, it is not cancer-specific. This shortcoming suggests the need to find new and more specific molecular markers. Several emerging PCa biomarkers have been evaluated or are being assessed for their potential use. There is increasing interest in the prospective use of extracellular vesicles as specific markers; it is well known that the content of vesicles is dependent on their cellular origin and is strongly related to the stimulus that triggers the release of the vesicles. Consequently, the identification of a disease-specific molecule (protein, lipid or RNA) associated with vesicles could facilitate their use as novel biological markers. The present review describes severalin vitrostudies that demonstrate the role of vesicles in PCa progression and severalin vivostudies that highlight the potential use of vesicles as PCa biomarkers.

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