Fc Fragment of IgE Receptor Ig (FCER1G) acts as a key gene involved in cancer immune infiltration and tumour microenvironment.

Although recent studies have revealed the relationship between Fc Fragment of IgE Receptor Ig (FCER1G) and human tumours, there is still a lack of a more comprehensive pan-cancer analysis of FCER1G as an immune-related gene. In this study, we investigated the expression pattern and prognostic value of FCER1G based on multiple databases. Subsequently, we further explored the role of FCER1G in tumour proliferation and metastasis, as well as its genomic alterations and DNA methylation levels, we next assessed the association between FCER1G and the immune infiltrating cells of the tumour microenvironment in different cancers and verified it by immunohistochemical staining. The correlation between FCER1G and immune checkpoint genes expression and its predictive power in the immune checkpoint blockade treatment cohorts were used to evaluate the importance of FCER1G in immunotherapy. Enrichment analysis of FCER1G-associated partners was also performed. In addition, we substantiated the expression of FCER1G in specific cell types of different tumours using single-cell RNA sequencing data from different databases. Our research results showed that FCER1G is up-regulated in most tumour. Positive associations were found between FCER1G expression and tumour prognosis, proliferation, and metastasis, we also found that FCER1G is closely related to the tumour microenvironment and tumour immunity. Moreover, FCER1G-associated partners were enriched in pathways associated with neutrophils activation. Finally, we confirmed that FCER1G was mainly expressed in monocyte/macrophages of the tumour microenvironment. In conclusion, our findings provided a comprehensive understanding of FCER1G in oncogenesis and tumour immunology among various tumours and demonstrated its potential value in prognosis prediction and tumour immunotherapy.

A new histone deacetylase inhibitor remodels the tumor microenvironment by deletion of polymorphonuclear myeloid-derived suppressor cells and sensitizes prostate cancer to immunotherapy.

BACKGROUND: Prostate cancer (PCa) is the most common malignancy diagnosed in men. Immune checkpoint blockade (ICB) alone showed disappointing results in PCa. It is partly due to the formation of immunosuppressive tumor microenvironment (TME) could not be reversed effectively by ICB alone. METHODS: We used PCa cell lines to evaluate the combined effects of CN133 and anti-PD-1 in the subcutaneous and osseous PCa mice models, as well as the underlying mechanisms. RESULTS: We found that CN133 could reduce the infiltration of polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs), and CN133 combination with anti-PD-1 could augment antitumor effects in the subcutaneous PCa of allograft models. However, anti-PD-1 combination with CN133 failed to elicit an anti-tumor response to the bone metastatic PCa mice. Mechanistically, CN133 could inhibit the infiltration of PMN-MDSCs in the TME of soft tissues by downregulation gene expression of PMN-MDSC recruitment but not change the gene expression involved in PMN-MDSC activation in the CN133 and anti-PD-1 co-treatment group relative to the anti-PD-1 alone in the bone metastatic mice model. CONCLUSIONS: Taken together, our work firstly demonstrated that combination of CN133 with anti-PD-1 therapy may increase the therapeutic efficacy to PCa by reactivation of the positive immune microenvironment in the TME of soft tissue PCa.

Noninvasive Positron Emission Tomography Imaging of SIRT1 in a Model of Early-Stage Alcoholic Liver Disease.

Accrued evidence has indicated that epigenetic mechanisms altered by alcohol have been implicated in the progression and development of alcoholic liver disease (ALD). SIRT1 plays an important role in ALD progression and has emerged as a promising therapeutic target for treating ALD. The purpose of this study is to investigate the efficacy of [11C]WL-1 for quantitative imaging of SIRT1 in mouse models of early-stage ALD. Positron emission tomography/computerized tomography (PET/CT) imaging was carried out 60 min following the injection of [11C]WL-1 in mouse models of early-stage ALD and normal control mice. The time-activity curves for ALD mouse livers showed remarkably decreased total uptake of [11C]WL-1 relative to that for control mouse livers. Moreover, compared with the normal control mice, decreased uptake in the cortex, hippocampus, and cerebellum was also observed in early-stage ALD mice, while the uptake of [11C]WL-1 in amygdala showed no significant changes. Western blot analysis confirmed that the protein levels of SIRT1 in the brains of early-stage ALD mice were decreased significantly when compared to the normal control mouse brains. Collectively, PET imaging with [11C]WL-1 would facilitate future clinical studies, aiming to demonstrate the roles of SIRT1 in ALD.

PET Imaging of Bromodomain and Extra-Terminal Domain Inhibitors for the Noninvasive Assessment of Metabolic Changes in the Liver and Brain of Early-Stage Alcoholic Liver Disease.

Alcoholic liver disease (ALD) has a significant impact on human health and is one of the leading causes of liver disease mortality. The early and exact diagnosis of ALD is very important since the early stage of disease progression can be reversible. Although ALD can be evaluated by ultrasound, CT, or MRI, there is still no imaging technique sufficient in the diagnosis of early-stage ALD. Of the current studies, epigenetic modulation plays a significant role in the development and progression of ALD. In this work, we evaluate whether BRDs play a vital role in the early-stage ALD using our new PET imaging probe of BET proteins, [11C]CW22. PET/CT imaging of [11C]CW22 and [18F]FDG was used to identify early-stage lesions of livers and brains in the mice model. We found that the average uptake values of livers and brains in early-stage ALD were significantly increased for [11C]CW22 PET/CT imaging but only slightly changed in [18F]FDG PET/CT imaging. Consistently, we also found that BRD 3, 4 protein expression levels were significantly higher in the liver and brain tissues of early-stage ALD. Furthermore, through Pmod software, we found that [11C]CW22 PET/CT uptakes in the brain stem, cerebellum, and midbrain were significantly up-regulated in the early-stage ALD. In conclusion, BRDs were important mediators of damage in early-stage ALD. [11C]CW22 PET/CT imaging can detect the early-phase alcohol-induced damage of livers and brains, which will likely lead to human trials in the future.

Imaging assisted evaluation of antitumor efficacy of a new histone deacetylase inhibitor in the castration-resistant prostate cancer.

PURPOSE: Castration-resistant prostate cancer (CRPC) is the most common cause of death in men. The effectiveness of HDAC inhibitors has been demonstrated by preclinical models, but not in clinical studies, probably due to the ineffectively accumulation of HDACI in prostate cancer cells. The purpose of this work was to evaluate effects of a novel HDACI (CN133) on CRPC xenograft model and 22Rv1 cells, and develops methods, PET/CT imaging, to detect the therapeutic effects of CN133 on this cancer. METHODS: We designed and performed study to compare the effects of CN133 with SAHA on the 22Rv1 xenograft model and 22Rv1 cells. Using PET/CT imaging with [11C] Martinostat and [18F] FDG, we imaged mice bearing 22Rv1 xenografts before and after 21-day treatment with placebo and CN133 (1 mg/kg), and uptake on pre-treatment and post-treatment imaging was measured. The anti-tumor mechanisms of CN133 were investigated by qPCR, western blot, and ChIP-qPCR. RESULTS: Our data showed that the CN133 treatment led to a 50% reduction of tumor volume compared to the placebo that was more efficacious than SAHA treatment in this preclinical model. [11C] Martinostat PET imaging could identify early lesions of prostate cancer and can also be used to monitor the therapeutic effect of CN133 in CRPC. Using pharmacological approaches, we demonstrated that effects of CN133 showed almost 100-fold efficacy than SAHA treatment in the experiment of cell proliferation, invasion, and migration. The anti-tumor mechanisms of CN133 were due to the inhibition of AR signaling pathway activity by decreased HDAC 2 and 3 protein expressions. CONCLUSION: Taken together, these studies provide not only a novel epigenetic approach for prostate cancer therapy but also offering a potential tool, [11C] Martinostat PET/CT imaging, to detect the early phase of prostate cancer and monitor therapeutic effect of CN133. These results will likely lead to human trials in the future.

The relationship between gut microbiota and short chain fatty acids in the renal calcium oxalate stones disease.

The relationship of gut microbiota and calcium oxalate stone has been limited investigated, especially with no study of gut microbiota and short chain fatty acids (SCFAs) in nephrolithiasis. We provided Sprague Dawley rats of renal calcium oxalate stones with antibiotics and examined the renal crystals deposition. We also performed a case-control study by analyzing 16S rRNA microbial profiling, shotgun metagenomics and SCFAs in 153 fecal samples from non-kidney stone (NS) controls, patients with occasional renal calcium oxalate stones (OS) and patients with recurrent stones (RS). Antibiotics reduced bacterial load in feces and could promote the formation of renal calcium crystals in model rats. In addition, both OS and RS patients exhibited higher fecal microbial diversity than NS controls. Several SCFAs-producing gut bacteria, as well as metabolic pathways associated with SCFAs production, were considerably lower in the gut microbiota among the kidney stone patients compared with the NS controls. Representation of genes involved in oxalate degradation showed no significance difference among groups. However, fecal acetic acid concentration was the highest in RS patients with high level of urinary oxalate, which was positively correlated with genes involvement in oxalate synthesis. Administration of SCFAs reduced renal crystals. These results shed new light on bacteria and SCFAs, which may promote the development of treatment strategy in nephrolithiasis.

Molecular imaging of NAD+ -dependent deacetylase SIRT1 in the brain.

INTRODUCTION: Aging is an inevitable physiological process and the biggest risk factor of Alzheimer's disease (AD). Developing an imaging tracer to visualize aging-related changes in the brain may provide a useful biomarker in elucidating neuroanatomical mechanisms of AD. METHODS: We developed and characterized a new tracer that can be used to visualize SIRT1 in brains related to aging and AD by positron emission tomography imaging. RESULTS: The SIRT1 tracer displayed desirable brain uptake and selectivity, as well as stable metabolism and proper kinetics and distribution in rodent and nonhuman primate brains. This new tracer was further validated by visualizing SIRT1 in brains of AD transgenic mice, compared to nontransgenic animals. DISCUSSION: Our SIRT1 tracer not only enables, for the first time, the demonstration of SIRT1 in animal brains, but also allows visualization and recapitulation of AD-related SIRT1 neuropathological changes in animal brains.

Safety and efficacy of parenteral fish oil-containing lipid emulsions in premature neonates.

OBJECTIVE: The aim of the study was to evaluate the safety and efficacy of fish oil-containing (FO) lipid emulsions that are rich in ω-3 fatty acids for parenteral nutrition in preterm neonates by using data retrieved from randomized controlled trials. METHODS: We performed a meta-analysis of 8 randomized controlled trials representing 483 premature neonates to compare FO with control (CO) lipid emulsions. RESULTS: This meta-analysis revealed that the levels of ω-3 fatty acids in the form of docosahexaenoic acid, eicosapentaenoic acid, and arachidonic acid (% of total fatty acids) in plasma were statistically higher in FO groups (mean difference [MD] -0.7%, 95% confidence interval [CI] -1.05 to -0.36, P < 0.001; MD -1.31%, 95% CI -1.40 to -1.21, P < 0.001). The differences were found in red blood cell (RBC) membranes. The levels of arachidonic acid (% of total fatty acids) as ω-6 fatty acid in plasma and red blood cell membranes were significantly lower in FO groups (MD 1.27%, 95% CI 1.12-1.42, P < 0.001) (MD 0.92%, 95% CI 0.12-1.72, P = 0.02). The mean body weight, serum level of bilirubin, triglycerides or C-reactive protein, all-cause mortality, and rate of lipid emulsion-associated complications were, however, not different between FO and CO groups. CONCLUSIONS: The level of docosahexaenoic acid is efficiently improved by FO lipid emulsions. The changes observed in eicosapentaenoic acid and arachidonic acid, and the associated safety issue, however, remain to be clarified. Any clinical benefit or detrimental effect of using FO in premature neonates cannot be demonstrated by the present study.

LncRNA MAGI2-AS3 inhibites tumor progression by up-regulating STAM via interacting with miR-142-3p in clear cell renal cell carcinoma.

Revealing the role of non-coding RNAs (ncRNAs) in inducing dysregulated pathological responses to external signals may identify therapeutic targets for inhibiting the progression of clear cell renal cell carcinoma (ccRCC). Non-coding RNAs belong to a class of RNA molecules that do not encode proteins but possess diverse biological functions, playing essential roles in the occurrence and development of metastatic and proliferative tumors. To investigate the impact of the upstream interaction between miR-142-3p and lncRNA MAGI2-AS3 on the tumor-suppressive activity of the STAM gene, we firstly conducted bioinformatics analysis to predict the upstream miRNAs of STAM and the upstream lncRNAs of the miRNAs through online databases (miRanda, miRDB, TargetScan, LncBase v2), which were further validated by the starBasev2.0 database. Subsequently, multiple experimental techniques were employed to validate these findings, including RT-qPCR, Western blotting, measurement of cellular functional activity, and luciferase reporter assays. Through these experimental methods, we provided compelling evidence regarding the role of miR-142-3p and MAGI2-AS3 in regulating STAM gene expression and functionality, revealing their potential significance in tumor suppression. Our research demonstrates the importance of the MAGI2-AS3/miR-142-3p/STAM signaling pathway axis in ccRCC. MAGI2-AS3 competes for binding with miR-142-3p, resulting in upregulated STAM gene expression. This upregulation inhibits tumor proliferation and metastasis in ccRCC cells. Conversely, overexpression of miR-142-3p or silencing of MAGI2-AS3 promotes tumor behavior, while downregulation of miR-142-3p inhibits the development of ccRCC. Targeting the MAGI2-AS3/miR-142-3p/STAM axis holds promise as a therapeutic strategy for ccRCC treatment.

COVID-19 inhibits spermatogenesis in the testes by inducing cellular senescence.

Introduction: COVID-19 (SARS-CoV-2) has been linked to organ damage in humans since its worldwide outbreak. It can also induce severe sperm damage, according to research conducted at numerous clinical institutions. However, the exact mechanism of damage is still unknown. Methods: In this study, testicular bulk-RNA-seq Data were downloaded from three COVID-19 patients and three uninfected controls from GEO to evaluate the effect of COVID-19 infection on spermatogenesis. Relative expression of each pathway and the correlation between genes or pathways were analyzed by bioinformatic methods. Results: By detecting the relative expression of each pathway and the correlation between genes or pathways, we found that COVID-19 could induce testicular cell senescence through MAPK signaling pathway. Cellular senescence was synergistic with MAPK pathway, which further affected the normal synthesis of cholesterol and androgen, inhibited the normal synthesis of lactate and pyruvate, and ultimately affected spermatogenesis. The medications targeting MAPK signaling pathway, especially MAPK1 and MAPK14, are expected to be effective therapeutic medications for reducing COVID-19 damage to spermatogenesis. Conclusion: These results give us a new understanding of how COVID-19 inhibits spermatogenesis and provide a possible solution to alleviate this damage.

Design, Synthesis, and Evaluation of Thienodiazepine Derivatives as Positron Emission Tomography Imaging Probes for Bromodomain and Extra-Terminal Domain Family Proteins.

To better understand the role of bromodomain and extra-terminal domain (BET) proteins in epigenetic mechanisms, we developed a series of thienodiazepine-based derivatives and identified two compounds, 3a and 6a, as potent BET inhibitors. Further in vivo pharmacokinetic studies and analysis of in vitro metabolic stability of 6a revealed excellent brain penetration and reasonable metabolic stability. Compounds 3a and 6a were radiolabeled with fluorine-18 in two steps and utilized in positron emission tomography (PET) imaging studies in mice. Preliminary PET imaging results demonstrated that [18F]3a and [18F]6a have good brain uptake (with maximum SUV = 1.7 and 2, respectively) and binding specificity in mice brains. These results show that [18F]6a is a potential PET radiotracer that could be applied to imaging BET proteins in the brain. Further optimization and improvement of the metabolic stability of [18F]6a are still needed in order to create optimal PET imaging probes of BET family members.

Development of a Novel Positron Emission Tomography (PET) Radiotracer Targeting Bromodomain and Extra-Terminal Domain (BET) Family Proteins.

Bromodomain and extra-terminal domain (BET) family proteins have become a hot research area because of their close relationship with a variety of human diseases. The non-invasive imaging technique, such as positron emission tomography (PET), provides a powerful tool to visualize and quantify the BET family proteins that accelerating the investigation of this domain. Herein, we describe the development of a promising PET probe, [ 11 C]1, specifically targeting BET family proteins based on the potent BET inhibitor CF53. [ 11 C]1 was successfully radio-synthesized with good yield and high purity after the optimization of radiolabeling conditions. The in vivo bio-activities evaluation of [ 11 C]1 was performed using PET imaging in rodents. The results demonstrated that [ 11 C]1 has favorable uptake in peripheral organs and moderate uptake in the brain. Further blocking studies indicated the high binding specificity and selectivity for BET proteins of this probe. Our findings suggest that [ 11 C]1 is a promising BET PET probe for BET proteins as well as epigenetic imaging.

Radiosynthesis and in vivo evaluation of a new positron emission tomography radiotracer targeting bromodomain and extra-terminal domain (BET) family proteins.

INTRODUCTION: Bromodomain and extra-terminal domain (BET) family proteins play a vital role in the epigenetic regulation process by interacting with acetylated lysine (Ac-K) residues in histones. BET inhibitors have become promising candidates to treat various diseases through the inhibition of the interaction between BET bromodomains and Ac-K of histone tails. With a molecular imaging probe, noninvasive imaging such as positron emission tomography (PET) can visualize the distribution and roles of BET family proteins in vivo and enlighten our understanding of BET protein function in both healthy and diseased tissue. METHODS: We radiolabeled the potent BET inhibitor INCB054329 by N-methylation to make [11C]PB003 as a BET PET radiotracer. The bioactivity evaluation of unlabeled PB003 in vitro was performed to confirm its binding affinity for BRDs, then the PET/CT imaging in rodents was performed to evaluate the bioactivity of [11C]PB003 in vivo. RESULTS: In our in vitro evaluation, PB003 showed a high BET binding affinity for BRDs (Kd = 2 nM, 1.2 nM, and 1.2 nM for BRD2, BRD3, and BRD4, respectively). In vivo PET/CT imaging demonstrated that [11C]PB003 has favorable uptake with appropriate kinetics and distributions in main peripheral organs. Besides, the blockade of [11C]PB003 binding was found in our blocking study which indicated the specificity of [11C]PB003. However, the BBB penetration and brain uptake of [11C]PB003 was limited, with only a maximum 0.2% injected dose/g at ~2 min post-injection. CONCLUSION: The imaging results in rodents in vivo demonstrate that [11C]PB003 binds to BET with high selectivity and specificity and has favorable uptake in peripheral organs. However, the low brain uptake of [11C]PB003 limits the visualization of brain regions indicating the efforts are still needed to discover the new BET imaging probes for brain visualization.

Design, synthesis and biological evaluation of novel O-carbamoyl ferulamide derivatives as multi-target-directed ligands for the treatment of Alzheimer's disease.

A novel series of O-carbamoyl ferulamide derivatives were designed by multitarget-directed ligands (MTDLs) strategy, the derivatives were synthesized and evaluated to treat Alzheimer's disease (AD). In vitro biological evaluation demonstrated that compound 4f was the best pseudo-irreversible hBChE (human butyrylcholinesterase) inhibitor with an IC50 value of 0.97 µM 4f was a potent selective MAO-B (monoamine oxidase-B) inhibitor (IC50 = 5.3 µM), and could inhibit (58.2%) and disaggregate (43.3%) self-mediated Aß aggregation. 4f also could reduce the levels of pathological tau and APP clearance, and displayed a wide safe range hepatotoxicity on LO2 cells. The in vivo studies revealed that 4f exhibited fascinating dyskinesia recovery rate and response efficiency on AlCl3-mediated zebrafish, and demonstrated significant protective effect on vascular injury caused by Aß1-40. PET-CT imaging demonstrated that [11C]4f exhibited high BBB penetration (especially could reach to hippocampus and striatum of brain) and had a fast brain uptake after intravenous bolus injection. Furthermore, compound 4f could improve scopolamine-induced cognitive impairment. Further, the metabolism in vitro of 4f was also investigated, and presented 3 metabolites in rat liver microsome metabolism, 4 metabolites in human liver microsome, and 4 metabolites in rat intestinal flora, providing previous data for the preclinical study. Therefore, these results implied that compound 4f was an advanced multi-function agent and deserved further preclinical study against mild-to-serve Alzheimer's disease.

Molecular imaging of Alzheimer's disease-related gamma-secretase in mice and nonhuman primates.

The pathogenesis of Alzheimer's disease (AD) is primarily driven by brain accumulation of the amyloid-ß-42 (Aß42) peptide generated from the amyloid-ß precursor protein (APP) via cleavages by ß- and γ-secretase. γ-Secretase is a prime drug target for AD; however, its brain regional expression and distribution remain largely unknown. Here, we are aimed at developing molecular imaging tools for visualizing γ-secretase. We used our recently developed γ-secretase modulators (GSMs) and synthesized our GSM-based imaging agent, [11C]SGSM-15606. We subsequently performed molecular imaging in rodents, including AD transgenic animals, and macaques, which revealed that our probe displayed good brain uptake and selectivity, stable metabolism, and appropriate kinetics and distribution for imaging γ-secretase in the brain. Interestingly, rodents and macaques shared certain brain areas with high γ-secretase expression, suggesting a functional conservation of γ-secretase. Collectively, we have provided the first molecular brain imaging of γ-secretase, which may not only accelerate our drug discovery for AD but also advance our understanding of AD.

Synthesis of 11C-labeled DNA polymerase-ß inhibitor 5-methoxyflavone and PET/CT imaging thereof.

INTRODUCTION: "Cell-cycle hypothesis" is emerging in recent years to suggest that aberrant cell cycle re-entry of differentiated neurons leads to a remarkable genetic disequilibrium which is likely to be the primary cause of neuronal apoptosis. DNA polymerase-ß is involved in neuronal DNA replication during cell cycle re-entry, thus constituting a promising target for Alzheimer's disease treatment. Recently, 5-methoxyflavone was identified as a candidate molecule endowed with good biological activity and selectivity on the DNA pol-ß in multiple in vitro AD models. In vivo assays, especially the brain uptake of 5-methoxyflavone, is need to be evaluated for further development for AD treatment. We report herein the synthesis of 11C-labeled 5-methoxyflavone, and the evaluation of in vivo properties of 5-[11C]methoxyflavone in rodents. METHODS: The strategy for synthesis of 5-[11C]methoxyflavone was developed by treating precursor 5-hydroxyflavone with [11C]CH3I and KOH in anhydrous DMF. 5-[11C]Methoxyflavone was purified, then evaluated in mice by using PET/CT imaging. RESULTS: The 5-[11C]methoxyflavone was synthesized conveniently in an average decay corrected yield of 22% (n = 3) with a radiochemical purity >99%. The average molar radioactivity of 5-[11C]methoxyflavone was 383 GBq/µmol. The average concentration was 0.107 µg/mL. PET/CT imaging in mice showed 5-[11C]methoxyflavone rapidly passed through the blood-brain barrier with 8.36 ±â€¯0.61%ID/g at 2 min post injection, and the radioactivity accumulation in brain was still noticeable with 2.48 ±â€¯0.59%ID/g at 28 min post injection. The clearance rate was 3.37 (brain2 min/brain28 min ratio). The blood and muscle uptakes were low. The lung displayed high initial uptake and subsequent rapid clearance, while the liver and kidney displayed a relatively slow clearance. Real-time imaging showed that 5-[11C]methoxyflavone accumulated immediately in the heart, then transferred to the liver and intestine, and was not observed in lower digestive tract. CONCLUSIONS: 5-[11C]Methoxyflavone was synthesized conveniently in one step. The results of PET/CT imaging in C57BL/6 mice suggested 5-[11C]methoxyflavone possesses appropriate pharmacokinetic properties and favorable brain uptake, thus being proved to be suitable for further development for AD treatment.

Novel radioligands for imaging sigma-1 receptor in brain using positron emission tomography (PET).

The sigma-1 receptor (σ 1R) is a unique intracellular protein. σ 1R plays a major role in various pathological conditions in the central nervous system (CNS), implicated in several neuropsychiatric disorders. Imaging of σ 1R in the brain using positron emission tomography (PET) could serve as a noninvasively tool for enhancing the understanding of the disease's pathophysiology. Moreover, σ 1R PET tracers can be used for target validation and quantification in diagnosis. Herein, we describe the radiosynthesis, in vivo PET/CT imaging of novel σ 1R 11C-labeled radioligands based on 6-hydroxypyridazinone, [11C]HCC0923 and [11C]HCC0929. Two radioligands have high affinities to σ 1R, with good selectivity. In mice PET/CT imaging, both radioligands showed appropriate kinetics and distributions. Additionally, the specific interactions of two radioligands were reduced by compounds 13 and 15 (self-blocking). Of the two, [11C]HCC0929 was further investigated in positive ligands blocking studies, using classic σ 1R agonist SA 4503 and σ 1R antagonist PD 144418. Both σ 1R ligands could extensively decreased the uptake of [11C]HCC0929 in mice brain. Besides, the biodistribution of major brain regions and organs of mice were determined in vivo. These studies demonstrated that two radioligands, especially [11C]HCC0929, possessed ideal imaging properties and might be valuable tools for non-invasive quantification of σ 1R in brain.