ABSTRACT
Radiopharmaceutical is an essential component of nuclear medicine and molecular imaging, as well as a key component of precision medicine. The United States Food and Drug Administration (FDA) has recently approved the marketing of several peptide-based radiopharmaceuticals, sparking a global trend of research in this area and propelling nuclear medicine into the precision theranostic era. This has created a new wave of technological competition in the field of nuclear medicine. It is the responsibility of Chinese scientists in the radiopharmaceutical field to capitalize on this opportunity, leverage the momentum, and strengthen their independent innovation capability in order to stay ahead in the future global nuclear science and technology competition. This review provides an overview of the remarkable progress made in the research, development, and translation of global peptide-based radiopharmaceuticals. It examines the advantages of peptide-based radiopharmaceuticals and outlines the current hot targets and progress in drug development in this field. Additionally, it proposes six opportunities for China to overtake others in the field of peptide-based radiopharmaceuticals and achieve technological self-reliance, based on interdisciplinary collaboration and independent innovation. Lastly, the future prospect of peptide-based radiopharmaceuticals is discussed.
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Peptides that are composed of dextrorotary (d)-amino acids have gained increasing attention as a potential therapeutic class. However, our understanding of the in vivo fate of d-peptides is limited. This highlights the need for whole-body, quantitative tracking of d-peptides to better understand how they interact with the living body. Here, we used mouse models to track the movement of a programmed death-ligand 1 (PD-L1)-targeting d-dodecapeptide antagonist (DPA) using positron emission tomography (PET). More specifically, we profiled the metabolic routes of [64Cu]DPA and investigated the tumor engagement of [64Cu/68Ga]DPA in mouse models. Our results revealed that intact [64Cu/68Ga]DPA was primarily eliminated by the kidneys and had a notable accumulation in tumors. Moreover, a single dose of [64Cu]DPA effectively delayed tumor growth and improved the survival of mice. Collectively, these results not only deepen our knowledge of the in vivo fate of d-peptides, but also underscore the utility of d-peptides as radiopharmaceuticals.
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As a serine hydrolase, monoacylglycerol lipase (MAGL) is principally responsible for the metabolism of 2-arachidonoylglycerol (2-AG) in the central nervous system (CNS), leading to the formation of arachidonic acid (AA). Dysfunction of MAGL has been associated with multiple CNS disorders and symptoms, including neuroinflammation, cognitive impairment, epileptogenesis, nociception and neurodegenerative diseases. Inhibition of MAGL provides a promising therapeutic direction for the treatment of these conditions, and a MAGL positron emission tomography (PET) probe would greatly facilitate preclinical and clinical development of MAGL inhibitors. Herein, we design and synthesize a small library of fluoropyridyl-containing MAGL inhibitor candidates. Pharmacological evaluation of these candidates by activity-based protein profiling identified
ABSTRACT
The 18 kDa translocator protein (TSPO), previously known as the peripheral benzodiazepine receptor, is predominately localized to the outer mitochondrial membrane in steroidogenic cells. Brain TSPO expression is relatively low under physiological conditions, but is upregulated in response to glial cell activation. As the primary index of neuroinflammation, TSPO is implicated in the pathogenesis and progression of numerous neuropsychiatric disorders and neurodegenerative diseases, including Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), Parkinson's disease (PD), multiple sclerosis (MS), major depressive disorder (MDD) and obsessive compulsive disorder (OCD). In this context, numerous TSPO-targeted positron emission tomography (PET) tracers have been developed. Among them, several radioligands have advanced to clinical research studies. In this review, we will overview the recent development of TSPO PET tracers, focusing on the radioligand design, radioisotope labeling, pharmacokinetics, and PET imaging evaluation. Additionally, we will consider current limitations, as well as translational potential for future application of TSPO radiopharmaceuticals. This review aims to not only present the challenges in current TSPO PET imaging, but to also provide a new perspective on TSPO targeted PET tracer discovery efforts. Addressing these challenges will facilitate the translation of TSPO in clinical studies of neuroinflammation associated with central nervous system diseases.
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Xenograft mice are preclinical animal models of tumors and are widely utilized in anti-tumor research. PK/PD modeling of anti-tumor agents is an approach that can capture the time profile of the "dose-plasma concentration-biomarker level-tumor volume" process based on experimental data from xenograft mice using a non-linear mixed-effect model. PK/PD modeling can help optimize the dosing regimen for anti-tumor therapy, evaluate any synergistic effect and help identify an optimal schedule for combination therapy, as well as providing a preliminary estimate of a drug's efficacy and anti-tumor potency in the human body. PK/PD modeling can also help by quantitatively explaining the mechanism of the tumor-inhibitory effect as indicated by changes in biomarker levels after a drug acts on its target. This article provides a systematic summary of the background, application range, and limitations of the mainstream anti-tumor agent PK/PD models. Recent advances in model structure development are reviewed in detail. Finally, we discuss promising applications of PK/PD models in anti-tumor medicine development from the perspective of a drug's mechanism of action, optimization of combination therapy schedules, and their clinical translation.
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Objective: To identify and analyze the 50 most-cited gastroenterology and hepatology articles originating from mainland China
Methods: We utilized the 2015 edition of Journal Citation Reports and PubMed to determine the 50 most-cited gastroenterology and hepatology articles from 75 professional journals and four leading journals in clinical medicine, which are The New England Journal of Medicine, The Lancet, The Journal of the American Medical Association, and The British Medical Journal. Then we excluded the articles written outside mainland China and collected the basic information, including the title, authors, year of publication, source journal, city, institution, number of citations, and topic of the research
Results: The number of citations for the top 50 papers ranged from 279 to 89 [mean, 129]. These articles were published between 2005 and 2012, in which 2009 was the year with the largest number of highly cited papers [13]. All articles were published in 15 journals. The journal Hepatology published the largest number of articles [21], followed by Journal of Gastroenterology and Hepatology [4], Journal of Hepatology [4] and World Journal of Gastroenterology [4]. The top 50 articles originated mainly from Shanghai [20], Guangzhou [13] and Beijing [6]. Sun Yat-sen University produced most highly cited papers [10]. The number of basic research was far more than clinical research, of which the ratio was about 1.78[32:18]. In all these articles, hepatocellular carcinoma was the most-discussed topic [19], followed by hepatitis B virus [8] and endoscopic [5]
Conclusions: Although a large gap remains between mainland China and the global community, the gastroenterology and hepatology research from China is gradually recognized by the world
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Objective: To explore the eff ect of Fasudil on the invasion and metastatic abilities of human high metastatic liver cancer cells (HCCLM3) and the underlying mechanisms. Methods: HCCLM3 cells were incubated with 100 μmol/L Fasudil. Fluorescence staining forF-actin and Transwell assay were performed to observe the invasion ability of HCCLM3 cells. HCCLM3 cells were divided into 3 groups: a negative control group, a Fasudil group and a BTB/POZ domain containing 7 (BTBD7)-siRNA group. Western blot assay was performed to detect the expression levels of BTBD7, ras homolog family member C (RhoC) and Rho-associated, coiled-coil containing protein kinase 2 (ROCK2), matrix metalloproteinases 2 (MMP2) and MMP9. Zymogram analysis method was performed to detect the expression activities of MMP2 and MMP9. hTe BTBD7-siRNA group was served as a positive control. Results: In HCCLM3 cells treated with Fasudil, the invasion ability was significant decreased compared with the control group, concomitant with the down-regulated expression levels of BTBD7, RhoC and ROCK2 protein as well as the decreased activities of MMP2 and MMP9. Conclusion: Fasudil plays an important role in interfering BTBD7-ROCK2 signaling pathway and suppressing the invasion and metastasis of hepatocellular carcinoma.
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<p><b>OBJECTIVE</b>To establish an ideal CCl4 drug-induced liver injury model in vitro.</p><p><b>METHOD</b>Traditional method and improved method were adopted for preparing CCl4 injury liquid and drug-induced human liver HepG2 cell injury. Cell morphological change was observed under a bright-field microscope. The level of alanine aminotransferase (ALT) in supernatant was detected by biochemical method. 4-Methyl-tetrazolium (MTT) chromatometry was adopted for determining cell activity.</p><p><b>RESULT</b>The improved method showed better CCl4-induced injury effect than the traditional method. With the increase in the concentration of CCl4 injury liquid, the ALT level significantly increased, whereas the cell activity notably decreased. Particularly, 70% CCl4 injury liquid use for 4 hours could achieve the best injury effect.</p><p><b>CONCLUSION</b>The improved method could be used to establish an ideal CCl4 drug-induced liver injury model in vitro, which can lay foundation for further in vitro studies.</p>
Subject(s)
Humans , Alanine Transaminase , Metabolism , Aspartate Aminotransferases , Metabolism , Carbon Tetrachloride , Chemical and Drug Induced Liver Injury , Hep G2 Cells , Liver , Wounds and Injuries , Models, Biological , Superoxide Dismutase , MetabolismABSTRACT
<p><b>OBJECTIVE</b>To survey an outbreak of acute gastroenteritis in Lulong County and analyze the cause of the disease.</p><p><b>METHODS</b>Epidemiological methods were applied to investigate an outbreak of acute gastroenteritis occurred in June 2000 in Lulong County. Stool specimens were collected from diarrhea patients and were tested for human calicivirus by ELISA and RT-PCR. The products of RT-PCR were cloned and sequenced, then phylogenetic analysis was carried out.</p><p><b>RESULTS</b>In total, 736 farmers were surveyed, among them 134 had acute gastroenteritis, the attack rate was 18.20%, and one elderly patient died. The age of patients was from 1 to 77 years and the incidence of the disease among young people was higher with a peak in June 25 through 30. Six stool specimens were tested for caliciviruses by ELISA and 3 were positives, one of them was confirmed by RT-PCR and belonged to norovirus genotype GI/2. No other pathogens were detected.</p><p><b>CONCLUSION</b>Human calicivirus was confirmed to be the cause of the outbreak of acute gastroenteritis.</p>
Subject(s)
Humans , Acute Disease , Caliciviridae , Genetics , Caliciviridae Infections , Epidemiology , China , Epidemiology , Disease Outbreaks , Enzyme-Linked Immunosorbent Assay , Feces , Virology , Gastroenteritis , Epidemiology , Virology , RNA, Viral , Genetics , Reverse Transcriptase Polymerase Chain ReactionABSTRACT
<p><b>OBJECTIVE</b>To investigate the epidemiological characteristus of human caliciviruses (HuCVs) among children under 5 years of age with acute diarrhea and to estimate the disease burden in Lulong county.</p><p><b>METHODS</b>HuCVs were detected by enzyme linked immunosorbent assay (ELISA) and reverse transcription-polymerase chain reaction (RT-PCR). Some PCR amplicons were cloned and sequenced. Phylogenetic tree was constructed for strain characterization. The rate of HuCVs-attributed hospitalization was estimated according to the positive rate of HuCVs detection in fecal specimens collected from hospitalized diarrhea patients.</p><p><b>RESULTS</b>Between July 1999 and June 2001, 708 fecal specimens were collected, of which 393 rotavirus-negative and 5 rotavirus-positive specimens were detected for HuCVs. Thirty-one point six percentage of fecal specimens from patients with diarrhea was HuCVs positive. Among inpatients, HuCVs positive rate was 17.5%. HuCVs detection was mainly distributed in 3 - 17 mouth-old children, in winter. All 11 strains belonged to NLV GII in which 6 strains GII-3, 2 strains GII-4 and 3 strains GII-7, and they shared 55.1% - 100% nucleotide identity. NLV GII-4 and GII-7 were identified in 2000, while NLV GII-3 and GII-7 in 2001. The preliminary estimate of HuCVs-attributed hospitalization rate was 3.6 per thousand.</p><p><b>CONCLUSION</b>Human caliciviruses with different genotypes circulated among children in Lulong county with GII NLVs were the prevalent strains. The disease burden of HuCVs was second to rotavirus.</p>