Publications by authors named "Shaojuan Zhang"

29 Publications

  • Page 1 of 1

Recent developments on PET radiotracers for TSPO and their applications in neuroimaging.

Acta Pharm Sin B 2021 Feb 25;11(2):373-393. Epub 2020 Aug 25.

Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, MA 02114, USA.

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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.apsb.2020.08.006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7893127PMC
February 2021

F-Box Gene D5RF Is Regulated by Agrobacterium Virulence Protein VirD5 and Essential for Agrobacterium-Mediated Plant Transformation.

Int J Mol Sci 2020 Sep 14;21(18). Epub 2020 Sep 14.

College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.

We previously reported that the virulence protein VirD5 possesses transcriptional activation activity, binds to a specific DNA element D5RE, and is required for -mediated stable transformation, but not for transient transformation. However, direct evidence for a role of VirD5 in plant transcriptional regulation has been lacking. In this study, we found that the Arabidopsis gene (coding for VirD5 response F-box protein, ) is regulated by VirD5. has two alternative transcripts of 930 bp and 1594 bp that encode F-box proteins of 309 and 449 amino acids, designated as D5RF.1 and D5RF.2, respectively. D5RF.2 has a N-terminal extension of 140 amino acids compared to D5RF.1, and both of them are located in the plant cell nucleus. The promoter of the contains two D5RE elements and can be activated by VirD5. The expression of D5RF is downregulated when the host plant is infected with deleted . Similar to VirD5, D5RF also affects the stable but not transient transformation efficiency of . Some pathogen-responsive genes are downregulated in the mutant. In conclusion, this study further confirmed VirD5 as the plant transcription activator and identified as the first target gene of VirD5 in regulation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/ijms21186731DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7555846PMC
September 2020

Light-activatable cannabinoid prodrug for combined and target-specific photodynamic and cannabinoid therapy.

J Biomed Opt 2018 10;23(10):1-9

University of Pittsburgh, Department of Radiology, Pittsburgh, Pennsylvania, United States.

Cannabinoids are emerging as promising antitumor drugs. However, complete tumor eradication solely by cannabinoid therapy remains challenging. In this study, we developed a far-red light activatable cannabinoid prodrug, which allows for tumor-specific and combinatory cannabinoid and photodynamic therapy. This prodrug consists of a phthalocyanine photosensitizer (PS), reactive oxygen species (ROS)-sensitive linker, and cannabinoid. It targets the type-2 cannabinoid receptor (CB2R) overexpressed in various types of cancers. Upon the 690-nm light irradiation, the PS produces cytotoxic ROS, which simultaneously cleaves the ROS-sensitive linker and subsequently releases the cannabinoid drug. We found that this unique multifunctional prodrug design offered dramatically improved therapeutic efficacy, and therefore provided a new strategy for targeted, controlled, and effective antitumor cannabinoid therapy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1117/1.JBO.23.10.108001DOI Listing
October 2018

Combined CB2 receptor agonist and photodynamic therapy synergistically inhibit tumor growth in triple negative breast cancer.

Photodiagnosis Photodyn Ther 2018 Dec 18;24:185-191. Epub 2018 Sep 18.

Department of Radiology, University of Pittsburgh, 100 Technology Drive, Pittsburgh, PA, 15219, USA; Department of Medicine, University of Pittsburgh, 3501 Fifth Ave, Pittsburgh, PA, 15213, USA; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, 15261, USA; University of Pittsburgh Cancer Institute, Pittsburgh, PA, 15232, USA. Electronic address:

Triple negative breast cancer (TNBC) is the deadliest form of breast cancer because it is more aggressive, diagnosed at later stage and more likely to develop local and systemic recurrence. Many patients do not experience adequate tumor control after current clinical treatments involving surgical removal, chemotherapy and/or radiotherapy, leading to disease progression and significantly decreased quality of life. Here we report a new combinatory therapy strategy involving cannabinoid-based medicine and photodynamic therapy (PDT) for the treatment of TNBC. This combinatory therapy targets two proteins upregulated in TNBC: the cannabinoid CB2 receptor (CBR, a G-protein coupled receptor) and translocator protein (TSPO, a mitochondria membrane receptor). We found that the combined CBR agonist and TSPO-PDT treatment resulted in synergistic inhibition in TNBC cell and tumor growth. This combinatory therapy approach provides new opportunities to treat TNBC with high efficacy. In addition, this study provides new evidence on the therapeutic potential of CBR agonists for cancer.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.pdpdt.2018.09.006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6289793PMC
December 2018

Synthesis and Evaluation of a Tetra[6,7]quinoxalinoporphyrazine-based Near Infrared Photosensitizer.

RSC Adv 2017 30;7(80):50555-50561. Epub 2017 Oct 30.

Department of Radiology, University of Pittsburgh, 100 Technology Drive, Pittsburgh, PA 15219, USA.

Here we report a near infrared, water-soluble, functional and dendrimeric photosensitizer (PS) based on quinoxalinoporphyrazine structure. The photophysical properties and photodynamic therapy results suggest that this quinoxalinoporphyrazine-based dendrimer may serve as an efficient near infrared (NIR) PS platform.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/C7RA06348BDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5810975PMC
October 2017

VirD5 is required for efficient Agrobacterium infection and interacts with Arabidopsis VIP2.

New Phytol 2018 01 30;217(2):726-738. Epub 2017 Oct 30.

National Key Laboratory of Crop Genetic Improvement, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China.

During Agrobacterium (Agrobacterium tumefaciens) infection, the translocated virulence proteins (VirD2, VirE2, VirE3, VirF and VirD5) play crucial roles. It is thought that, through protein-protein interactions, Agrobacterium uses and abuses host plant factors and systems to facilitate its infection. Although some molecular functions have been revealed, the roles of VirD5 still need to be further elucidated. Here, plant transformation and tumorigenesis mediated by genetically modified Agrobacterium strains were performed to examine VirD5 roles. In addition, protein-protein interaction-associated molecular and biochemistry technologies were used to reveal and elucidate VirD5 interaction with Arabidopsis VirE2 interacting protein 2 (VIP2). Our results showed that deleting virD5 from Agrobacterium reduced its tumor formation ability and stable transformation efficiency but did not affect the transient transformation efficiency. We also found that VirD5 can interact with Arabidopsis VIP2. Further experiments demonstrated that VirD5 can affect VIP2 binding to cap-binding proteins (CBP20 and CBP80). The tumorigenesis efficiency for cbp80 mutant was not significantly changed, but that for cbp20, cbp20cbp80 mutants were significantly increased. This work demonstrates experimentally that VirD5 is required for efficient Agrobacterium infection and may promote this process by competitive interaction with Arabidopsis VIP2. CBP20 is involved in the Agrobacterium infection process and its effect can be synergistically enhanced by CBP80.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/nph.14854DOI Listing
January 2018

Multilayer photodynamic therapy for highly effective and safe cancer treatment.

Acta Biomater 2017 05 9;54:271-280. Epub 2017 Mar 9.

Department of Radiology, University of Pittsburgh, 100 Technology Drive, Pittsburgh, PA 15219, USA; Department of Medicine, University of Pittsburgh, 3501 Fifth Ave, Pittsburgh, PA 15213, USA; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261, USA; University of Pittsburgh Cancer Institute, Pittsburgh, PA 15232, USA. Electronic address:

Recent efforts to develop tumor-targeted photodynamic therapy (PDT) photosensitizers (PSs) have greatly advanced the potential of PDT in cancer therapy, although complete eradication of tumor cells by PDT alone remains challenging. As a way to improve PDT efficacy, we report a new combinatory PDT therapy technique that specifically targets multilayers of cells. Simply mixing different PDT PSs, even those that target distinct receptors (this may still lead to similar cell-killing pathways), may not achieve ideal therapeutic outcomes. Instead, significantly improved outcomes likely require synergistic therapies that target various cellular pathways. In this study, we target two proteins upregulated in cancers: the cannabinoid CB2 receptor (CBR, a G-protein coupled receptor) and translocator protein (TSPO, a mitochondria membrane receptor). We found that the CBR-targeted PS, IR700DX-mbc94, triggered necrotic cell death upon light irradiation, whereas PDT with the TSPO-targeted IR700DX-6T agent led to apoptotic cell death. Both PSs significantly inhibited tumor growth in vivo in a target-specific manner. As expected, the combined CBR- and TSPO-PDT resulted in enhanced cell killing efficacy and tumor inhibition with lower drug dose. The median survival time of animals with multilayer PDT treatment was extended by as much as 2.8-fold over single PDT treatment. Overall, multilayer PDT provides new opportunities to treat cancers with high efficacy and low side effects.

Statement Of Significance: Photodynamic therapy (PDT) is increasingly used as a minimally invasive, controllable and effective therapeutic procedure for cancer treatment. However, complete eradication of tumor cells by PDT alone remains challenging. In this study, we investigate the potential of multilayer PDT in cancer treatment with high efficacy and low side effects. Through PDT targeting two cancer biomarkers located at distinct subcellular localizations, remarkable synergistic effects in cancer cell killing and tumor inhibition were observed in both in vitro and in vivo experiments. This strategy may be widely applied to treat various cancer types by using strategically designed PDT photosensitizers that target corresponding upregulated receptors at tactical subcellular localization.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.actbio.2017.03.012DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5415343PMC
May 2017

Discovery of N-((1-(4-(3-(3-((6,7-Dimethoxyquinolin-3-yl)oxy)phenyl)ureido)-2-(trifluoromethyl)phenyl)piperidin-4-yl)methyl)propionamide (CHMFL-KIT-8140) as a Highly Potent Type II Inhibitor Capable of Inhibiting the T670I "Gatekeeper" Mutant of cKIT Kinase.

J Med Chem 2016 09 30;59(18):8456-72. Epub 2016 Aug 30.

High Magnetic Field Laboratory, Chinese Academy of Sciences , Mailbox 1110, 350 Shushanhu Road, Hefei, Anhui 230031, P. R. China.

cKIT kinase inhibitors, e.g., imatinib, could induce drug-acquired mutations such as cKIT T670I that rendered drug resistance after chronic treatment. Through a type II kinase inhibitor design approach we discovered a highly potent type II cKIT kinase inhibitor compound 35 (CHMFL-KIT-8140), which potently inhibited both cKIT wt (IC50 = 33 nM) and cKIT gatekeeper T670I mutant (IC50 = 99 nM). Compound 35 displayed strong antiproliferative effect against GISTs cancer cell lines GIST-T1 (cKIT wt, GI50 = 4 nM) and GIST-5R (cKIT T670I, GI50 = 26 nM). In the cellular context it strongly inhibited c-KIT mediated signaling pathways and induced apoptosis. In the BaF3-TEL-cKIT-T670I isogenic cell inoculated xenograft mouse model, 35 exhibited dose dependent tumor growth suppression efficacy and 100 mg/kg dosage provided 47.7% tumor growth inhibition (TGI) without obvious toxicity. We believe compound 35 would be a good pharmacological tool for exploration of the cKIT-T670I mutant mediated pathology in GISTs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.jmedchem.6b00902DOI Listing
September 2016

Ex Vivo Imaging, Biodistribution, and Histological Study in Addition to In Vivo Imaging.

Authors:
Shaojuan Zhang

Methods Mol Biol 2016 ;1444:183-91

Molecular Imaging Lab, Department of Radiology, University of Pittsburgh, Suite 452G, 100 Technology Drive, Pittsburgh, PA, 15219, USA.

In addition to in vivo fluorescence imaging, ex vivo evaluations including ex vivo imaging, biodistribution, and histological study are often conducted to further investigate the biological behavior of fluorescent probes. These studies can further confirm the localization of fluorescent probes at the target sites and demonstrate the probe distribution in various organs and tissues. Such studies can also be extended to cellular level for biochemical analysis. Therefore, ex vivo evaluations are valuable to fully characterizing fluorescent probes in a living system. This chapter provides an overview of techniques for evaluating pharmacological profiles of fluorescent probes ex vivo.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/978-1-4939-3721-9_16DOI Listing
January 2018

Before In Vivo Imaging: Evaluation of Fluorescent Probes Using Fluorescence Microscopy, Multiplate Reader, and Cytotoxicity Assays.

Authors:
Shaojuan Zhang

Methods Mol Biol 2016 ;1444:1-13

Molecular Imaging Lab, Department of Radiology, University of Pittsburgh, Suite 452G, 100 Technology Drive, Pittsburgh, PA, 15219, USA.

Fluorescent probes are widely utilized for noninvasive fluorescence imaging. Continuing efforts have been made in developing novel fluorescent probes with improved fluorescence quantum yield, enhanced target-specificity, and lower cytotoxicity. Before such probes are administrated into a living system, it is essential to evaluate the subcellular uptake, targeting specificity, and cytotoxicity in vitro. In this chapter, we briefly outline common methods used to evaluate fluorescent probes using fluorescence microscopy, multiplate reader, and cytotoxicity assay.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/978-1-4939-3721-9_1DOI Listing
January 2018

Imaging Agents in Targeting Tumor Hypoxia.

Curr Med Chem 2016 ;23(17):1775-800

Key Laboratory of Biomedical Information Engineering, Ministry of Education, School of Life Science and Technology, Xi`an Jiaotong University; Xi`an, P. R. China.

Tissue hypoxia may occur in many diseases, specifically during the occurrence and growth of malignant solid-tumors. Targeting hypoxia is one of the most significant characteristics of tumors in diagnosis, monitoring, and treatment. This review summarizes the current oxygen-sensitive imaging agents used to target tumor hypoxia, including positron-emission computed tomography/single photon-emission computed tomography radionuclide labeled tracers, magnetic resonance imaging contrast agents for hypoxia detection, and hypoxia-sensitive optical imaging probes. Researchers have utilized nanotechnology as a useful toolkit to improve the effects of oxygen-sensitive imaging agents. We emphasize the progress and influence of nanotechnology in these materials and technologies. This review demonstrates that hypoxia imaging agents have promising prospects, and may provide helpful information for tumor diagnosis and prognosis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.2174/0929867323666160321122023DOI Listing
February 2017

Tumor mitochondria-targeted photodynamic therapy with a translocator protein (TSPO)-specific photosensitizer.

Acta Biomater 2015 Dec 30;28:160-170. Epub 2015 Sep 30.

Molecular Imaging Laboratory, Department of Radiology, University of Pittsburgh, Pittsburgh, PA 15219, USA.

Unlabelled: Photodynamic therapy (PDT) has been proven to be a minimally invasive and effective therapeutic strategy for cancer treatment. It can be used alone or as a complement to conventional cancer treatments, such as surgical debulking and chemotherapy. The mitochondrion is an attractive target for developing novel PDT agents, as it produces energy for cells and regulates apoptosis. Current strategy of mitochondria targeting is mainly focused on utilizing cationic photosensitizers that bind to the negatively charged mitochondria membrane. However, such an approach is lack of selectivity of tumor cells. To minimize the damage on healthy tissues and improve therapeutic efficacy, an alternative targeting strategy with high tumor specificity is in critical need. Herein, we report a tumor mitochondria-specific PDT agent, IR700DX-6T, which targets the 18kDa mitochondrial translocator protein (TSPO). IR700DX-6T induced apoptotic cell death in TSPO-positive breast cancer cells (MDA-MB-231) but not TSPO-negative breast cancer cells (MCF-7). In vivo PDT study suggested that IR700DX-6T-mediated PDT significantly inhibited the growth of MDA-MB-231 tumors in a target-specific manner. These combined data suggest that this new TSPO-targeted photosensitizer has great potential in cancer treatment.

Statement Of Significance: Photodynamic therapy (PDT) is an effective and minimally invasive therapeutic technique for treating cancers. Mitochondrion is an attractive target for developing novel PDT agents, as it produces energy to cells and regulates apoptosis. Current mitochondria targeted photosensitizers (PSs) are based on cationic molecules, which interact with the negatively charged mitochondria membrane. However, such PSs are not specific for cancerous cells, which may result in unwanted side effects. In this study, we developed a tumor mitochondria-targeted PS, IR700DX-6T, which binds to translocator protein (TSPO). This agent effectively induced apoptosis in TSPO-positive cancer cells and significantly inhibited tumor growth in TSPO-positive tumor-bearing mice. These combined data suggest that IR700DX-6T could become a powerful tool in the treatment of multiple cancers that upregulate TSPO.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.actbio.2015.09.033DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4648641PMC
December 2015

Synthesis of a reactive oxygen species responsive heterobifunctional thioketal linker.

Tetrahedron Lett 2015 Sep;56(37):5242-5244

Molecular Imaging Laboratory, Department of Radiology, University of Pittsburgh, Pittsburgh, PA 15219, USA.

A new heterobifunctional reactive oxygen species (ROS) responsive thioketal linker and its synthesis are described. This linker allows for developing new ROS-responsive agents with two distinct functionalities using universal bioconjugation methods. The reaction kinetics of the thioketal cleavage in the presence of ROS is also described.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.tetlet.2015.07.059DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4545510PMC
September 2015

In vivo inflammation imaging using a CB2R-targeted near infrared fluorescent probe.

Am J Nucl Med Mol Imaging 2015 15;5(3):246-58. Epub 2015 Feb 15.

Molecular Imaging Laboratory, Department of Radiology, University of Pittsburgh Pittsburgh, PA 15219, USA ; Department of Bioengineering, University of Pittsburgh Pittsburgh, PA 15261, USA ; University of Pittsburgh Cancer Institute Pittsburgh, PA 15232, USA.

Chronic inflammation is considered as a critical cause of a host of disorders, such as cancer, rheumatoid arthritis, atherosclerosis, and neurodegenerative diseases, although the exact mechanism is yet to be explored. Imaging tools that can specifically target inflammation are therefore important to help reveal the role of inflammation in disease progression, and allows for developing new therapeutic strategies to ultimately improve patient care. The purpose of this study was to develop a new in vivo inflammation imaging approach by targeting the cannabinoid receptor type 2 (CB2R), an emerging inflammation biomarker, using a unique near infrared (NIR) fluorescent probe. Herein, we report the first in vivo CB2R-targeted NIR inflammation imaging study using a synthetic fluorescent probe developed in our laboratory, NIR760-mbc94. In vitro binding assay and fluorescence microscopy study indicate NIR760-mbc94 specifically binds towards CB2R in mouse RAW264.7 macrophage cells. Furthermore, in vivo imaging was performed using a Complete Freund's Adjuvant (CFA)-induced inflammation mouse model. NIR760-mbc94 successfully identified inflamed tissues and the probe uptake was blocked by a CB2R ligand, SR144528. Additionally, immunofluorescence staining in cryosectioned tissues validated the NIR760-mbc94 uptake in inflamed tissues. In conclusion, this study reports the first in vivo CB2R-targeted inflammation imaging using an NIR fluorescent probe. Specific targeting of NIR760-mbc94 has been demonstrated in macrophage cells, as well as a CFA-induced inflammation mouse model. The combined evidence indicates that NIR760-mbc94 is a promising inflammation imaging probe. Moreover, in vivo CB2R-targeted fluorescence imaging may have potential in the study of inflammation-related diseases.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4446393PMC
June 2015

A novel near-infrared fluorescence imaging probe that preferentially binds to cannabinoid receptors CB2R over CB1R.

Biomaterials 2015 Jul 28;57:169-78. Epub 2015 Apr 28.

Department of Radiology, University of Pittsburgh, 100 Technology Drive, Pittsburgh, PA 15219, USA; University of Pittsburgh Cancer Institute, Pittsburgh, PA 15232, USA. Electronic address:

The type 2 cannabinoid receptors (CB2R) have gained much attention recently due to their important regulatory role in a host of pathophysiological processes. However, the exact biological function of CB2R and how this function might change depending on disease progression remains unclear and could be better studied with highly sensitive and selective imaging tools for identifying the receptors. Here we report the first near infrared fluorescence imaging probe (NIR760-XLP6) that binds preferentially to CB2R over the type 1 cannabinoid receptors (CB1R). The selectivity of the probe was demonstrated by fluorescence microscopy using DBT-CB2 and DBT-CB1 cells. Furthermore, in mouse tumor models, NIR760-XLP6 showed significantly higher uptake in DBT-CB2 than that in DBT-CB1 tumors. These findings indicate that NIR760-XLP6 is a promising imaging tool for the study of CB2R regulation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.biomaterials.2015.04.018DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4426855PMC
July 2015

Phosphorescence monitoring of hypoxic microenvironment in solid-tumors to evaluate chemotherapeutic effects using the hypoxia-sensitive iridium (III) coordination compound.

PLoS One 2015 18;10(3):e0121293. Epub 2015 Mar 18.

The Key Laboratory of Biomedical Information Engineering, Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, P. R. China.

Objectives: To utilize phosphorescence to monitor hypoxic microenvironment in solid-tumors and investigate cancer chemotherapeutic effects in vivo.

Methods: A hypoxia-sensitive probe named BTP was used to monitor hypoxic microenvironment in solid-tumors. The low-dose metronomic treatment with cisplatin was used in anti-angiogenetic chemotherapeutic programs. The phosphorescence properties of BTP were detected by a spectrofluorometer. BTP cytotoxicity utilized cell necrosis and apoptosis, which were evaluated by trypan blue dye exclusion and Hoechst33342 plus propidium iodide assays. Tumor-bearing mouse models of colon adenocarcinoma were used for tumor imaging in vivo. Monitoring of the hypoxic microenvironment in tumors was performed with a Maestro 2 fluorescence imaging system. Tumor tissues in each group were harvested regularly and treated with pathological hematoxylin and eosin and immunohistochemical staining to confirm imaging results.

Results: BTP did not feature obvious cytotoxicity for cells, and tumor growth in low-dose metronomic cisplatin treated mice was significantly inhibited by chemotherapy. Hypoxic levels significantly increased due to cisplatin, as proven by the expression level of related proteins. Phosphorescence intensity in the tumors of mice in the cisplatin group was stronger and showed higher contrast than that in tumors of saline treated mice.

Conclusions: We develop a useful phosphorescence method to evaluate the chemotherapeutic effects of cisplatin. The proposed method shows potential as a phosphorescence imaging approach for evaluating chemotherapeutic effects in vivo, especially anti-angiogenesis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0121293PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4365010PMC
February 2016

DAMP, an acidotropic pH indicator, can be used as a tool to visualize non-esterified cholesterol in cells.

Acta Biochim Biophys Sin (Shanghai) 2015 Feb 12;47(2):73-9. Epub 2015 Jan 12.

Department of Gynaecology and Obstetrics, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, China.

Cholesterol-rich regions are attractive targets for studying metabolic disorders that involve accumulation of cholesterol. Despite efforts to develop probes for labelling cholesterol-rich regions in cells, few of these reagents have a low molecular weight. Previous studies have shown that the acidotropic pH indicator, N-{3-[(2,4-dinitrophenyl)amino]propyl}-N-(3-aminopropyl)methylamine dihydrochloride (DAMP), reacts with cholesterol-rich organelles, such as endocrine secretary granules from endocrine cells. In this study, we demonstrated that DAMP could react with free cholesterol in a dose-dependent manner, and DAMP was able to detect cholesterol-rich subcellular organelles. DAMP was sufficiently potent to detect free cholesterol-enriched organs, but was unable to detect atherosclerotic plaques primarily composed of esterified cholesterol. Taken together, these results demonstrate that DAMP facilitates the study of cholesterol-enriched lipid rafts and disorders which involve cholesterol accumulation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/abbs/gmu123DOI Listing
February 2015

Antibody-functionalized peptidic membranes for neutralization of allogeneic skin antigen-presenting cells.

Acta Biomater 2014 Nov 10;10(11):4759-4767. Epub 2014 Aug 10.

Division of Pharmaceutical Sciences, Duquesne University, PA, USA. Electronic address:

We report herein application of an in situ material strategy to attenuate allograft T cell responses in a skin transplant mouse model. Functionalized peptidic membranes were used to impede trafficking of donor antigen-presenting cells (dAPCs) from skin allografts in recipient mice. Membranes formed by self-assembling peptides (SAPs) presenting antibodies were found to remain underneath grafted skins for up to 6 days. At the host-graft interface, dAPCs were targeted by using a monoclonal antibody that binds to a class II major histocompatibility complex (MHC) molecule (I-A(d)) expressed exclusively by donor cells. Using a novel cell labeling near-infrared nanoemulsion, we found more dAPCs remained in allografts treated with membranes loaded with anti-I-A(d) antibodies than without. In vitro, dAPCs released from skin explants were found adsorbed preferentially on anti-I-A(d) antibody-loaded membranes. Recipient T cells from these mice produced lower concentrations of interferon-gamma cultured ex vivo with donor cells. Taken together, the data indicate that the strategy has the potential to alter the natural course of rejection immune mechanisms in allogeneic transplant models.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.actbio.2014.08.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4186902PMC
November 2014

Molecular imaging of human tumor cells that naturally overexpress type 2 cannabinoid receptors using a quinolone-based near-infrared fluorescent probe.

J Biomed Opt 2014 ;19(7):76016

University of Pittsburgh, Molecular Imaging Laboratory, Department of Radiology, Pittsburgh, Pennsylvania 15219dUniversity of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania 15232, United StateseUniversity of Pittsburgh, Department of Bioengineering.

Cannabinoid CB2 receptors (CB2R) hold promise as therapeutic targets for treating diverse diseases, such as cancers, neurodegenerative diseases, pain, inflammation, osteoporosis, psychiatric disorders, addiction, and immune disorders. However, the fundamental role of CB2R in the regulation of diseases remains unclear, largely due to a lack of reliable imaging tools for the receptors. The goal of this study was to develop a CB2R-targeted molecular imaging probe and evaluate the specificity of the probe using human tumor cells that naturally overexpress CB2R. To synthesize the CB2R-targeted probe (NIR760-Q), a conjugable CB2R ligand based on the quinolone structure was first prepared, followed by bioconjugation with a near-infrared (NIR) fluorescent dye, NIR760. In vitro fluorescence imaging and competitive binding studies showed higher uptake of NIR760-Q than free NIR760 dye in Jurkat human acute T-lymphoblastic leukemia cells. In addition, the high uptake of NIR760-Q was significantly inhibited by the blocking agent, 4-quinolone-3-carboxamide, indicating specific binding of NIR760-Q to the target receptors. These results indicate that the NIR760-Q has potential in diagnostic imaging of CB2R positive cancers and elucidating the role of CB2R in the regulation of disease progression.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1117/1.JBO.19.7.076016DOI Listing
February 2015

Cannabinoid CB2 receptor as a new phototherapy target for the inhibition of tumor growth.

Mol Pharm 2014 Jun 8;11(6):1919-29. Epub 2014 May 8.

Department of Radiology, Eastern Hepatobiliary Surgery Hospital, Second Military Medical University , Shanghai 200438, P. R. China.

The success of targeted cancer therapy largely relies upon the selection of target and the development of efficient therapeutic agents that specifically bind to the target. In the current study, we chose a cannabinoid CB2 receptor (CB2R) as a new target and used a CB2R-targeted photosensitizer, IR700DX-mbc94, for phototherapy treatment. IR700DX-mbc94 was prepared by conjugating a photosensitizer, IR700DX, to mbc94, whose binding specificity to CB2R has been previously demonstrated. We found that phototherapy treatment using IR700DX-mbc94 greatly inhibited the growth of CB2R positive tumors but not CB2R negative tumors. In addition, phototherapy treatment with nontargeted IR700DX did not show significant therapeutic effect. Similarly, treatment with IR700DX-mbc94 without light irradiation or light irradiation without the photosensitizer showed no tumor-inhibitory effect. Taken together, IR700DX-mbc94 is a promising phototherapy agent with high target-specificity. Moreover, CB2R appears to have great potential as a phototherapeutic target for cancer treatment.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/mp5001923DOI Listing
June 2014

Synthesis and optical properties of water-soluble biperylene-based dendrimers.

Chem Commun (Camb) 2014 May;50(42):5648-51

Molecular Imaging Laboratory, Department of Radiology, University of Pittsburgh, Pittsburgh, PA 15219, USA.

We report the synthesis and photophysical properties of three biperylene-based dendrimers, which show red fluorescence in water. A fluorescence microscopy study demonstrated uptake of biperylene-based dendrimers in living cells. Our results indicate that these biperylene-based dendrimers are promising candidates in fluorescence imaging applications with the potential as therapeutic carriers.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c4cc01742kDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4037920PMC
May 2014

Perfluorocarbon nanoemulsions with fluorescent, colloidal and magnetic properties.

Biomaterials 2014 Jun 25;35(18):4958-68. Epub 2014 Mar 25.

Molecular Imaging Laboratory, Department of Radiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15219, USA; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261, USA; University of Pittsburgh Cancer Institute, Pittsburgh, PA 15232, USA. Electronic address:

Bimodal imaging agents that combine magnetic resonance imaging (MRI) and nearinfrared (NIR) imaging formulated as nanoemulsions became increasingly popular for imaging inflammation in vivo. Quality of in vivo imaging using nanoemulsions is directly dependent on their integrity and stability. Here we report the design of nanoemulsions for bimodal imaging, where both photostability and colloidal stability are equally addressed. A highly chemically and photo stable quaterrylenediimide dye was introduced into perfluoro-15-crown-5 ether (PCE) nanoemulsions. The nanoemulsions were prepared with PCE and Miglyol 812N mixed at 1:1 v/v ratio as internal phase stabilized by non-ionic surfactants. Data shows exceptional colloidal stability demonstrated as unchanged droplet size (~130 nm) and polydispersity (<0.15) after 182 days follow up at both 4 and 25 °C. Nanoemulsions also sustained the exposure to mechanical and temperature stress, and prolonged exposure to light without changes in droplet size, (19)F signal or fluorescence signal. No toxicity was observed in vitro in model inflammatory cells upon 24 h exposure while confocal microscopy showed that nanoemulsions droplets accumulated in the cytoplasm. Overall, our data demonstrates that design of bimodal imaging agents requires consideration of stability of each imaging component and that of the nanosystem as a whole to achieve excellent imaging performance.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.biomaterials.2014.03.006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4058911PMC
June 2014

Targeted zwitterionic near infrared fluorescent probe for improved imaging of type 2 cannabinoid receptors.

J Biomed Opt 2014 Mar;19(3):36006

University of Pittsburgh, Department of Radiology, Molecular Imaging Laboratory, Pittsburgh, Pennsylvania 15219dUniversity of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania 15232.

Recent studies indicate that the type 2 cannabinoid receptors (CB2R) have become an attractive target for treating a variety of pathologies, including cancers, neurodegenerative diseases, inflammation, pain, osteoporosis, immunological disorders and drug abuse. In addition, it appears that many of these diseases have up-regulated CB2R expression. However, the precise role of CB2R in the regulation of diseases remains unclear. The ability to specifically image CB2R would contribute to develop reliable CB2R-based therapeutic approaches with a better understanding of the mechanism of CB2R action in these diseases. We developed a CB2R-targeted zwitterionic near-infrared (NIR) fluorescent probe, ZW760-mbc94. When compared with a previously reported CB2R probe (NIR760-mbc94) with the same targeting moiety but a charged NIR fluorescent dye, ZW760-mbc94 showed improved binding specificity in vitro and ex vivo. Overall, ZW760-mbc94 appears to have great potential as a CB2R-targeted contrast agent.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1117/1.JBO.19.3.036006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4019425PMC
March 2014

Target-selective phototherapy using a ligand-based photosensitizer for type 2 cannabinoid receptor.

Chem Biol 2014 Mar 27;21(3):338-44. Epub 2014 Feb 27.

Department of Radiology, University of Pittsburgh, 100 Technology Drive, Pittsburgh, PA 15219, USA; University of Pittsburgh Cancer Institute, 5150 Centre Avenue, Pittsburgh, PA 15232, USA. Electronic address:

Phototherapy is a powerful, noninvasive approach for cancer treatment, with several agents currently in clinical use. Despite the progress and promise, most current phototherapy agents have serious side effects as they can lead to damage to healthy tissue, even when the photosensitizers are fused to targeting molecules due to nonspecific light activation of the unbound photosensitizer. To overcome these limitations, we developed a phototherapy agent that combines a functional ligand and a near infrared phthalocyanine dye. Our target is type 2 cannabinoid receptor (CB2R), considered an attractive therapeutic target for phototherapy given it is overexpressed by many types of cancers that are located at a surface or can be reached by an endoscope. We show that our CB2R-targeted phototherapy agent, IR700DX-mbc94, is specific for CB2R and effective only when bound to the target receptor. Overall, this opens up the opportunity for development of an alternative treatment option for CB2R-positive cancers.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.chembiol.2014.01.009DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3989837PMC
March 2014

Hypoxia-sensitive bis(2-(2'-benzothienyl)pyridinato-N,C(3'))iridium[poly(n-butyl cyanoacrylate]/chitosan nanoparticles and their phosphorescence tumor imaging in vitro and in vivo.

Nanoscale 2013 Dec;5(24):12633-44

Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, P. R. China.

A new hypoxia-sensitive coordination compound, bis(2-(2'-benzothienyl)pyridinato-N,C(3'))iridium[poly(n-butyl cyanoacrylate)], hereafter denoted as (btp)2Ir(PBCA), is synthesized and characterized by (13)C nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FTIR). (btp)2Ir(PBCA)/chitosan [(btp)2Ir(PBCA)/CS] nanoparticles (NPs) with a core-shell structure are prepared by a two-step fabrication process. The size distributions of these NPs are measured with a Malvern size analyzer, and their morphology is observed by transmission electron microscopy (TEM). The functional groups on the surface are confirmed by FTIR. Phosphorescence spectra are obtained and lifetimes are determined with a spectrophotofluorometer and a time-correlated single photon counting (TCSPC) apparatus, respectively. HeLa and CT26 cell lines are used to examine the cytotoxicity by the MTT assay, as well as to determine the imaging capability of the samples in air and nitrogen atmospheres, respectively. Tumor-bearing mouse models of colon adenocarcinoma are used for tumor imaging in vivo, and the imaging effect is evaluated with a Maestro 2 fluorescence imaging system. Compared with the hypoxia-associated probe bis(2-(2'-benzothienyl)pyridinato-N,C(3'))iridium(acetylacetonate) (BTP), the phosphorescence lifetime of (btp)2Ir(PBCA)/CS NPs significantly decreases, but the hypoxia-sensitivity increases after preparation of NPs. Apart from the significantly lower cytotoxicity, (btp)2Ir(PBCA)/CS NPs also enhance the tumor imaging effect by more than 10 times, maintaining the phosphorescence signal in tumor tissue for over 24 h and significantly decreasing the phosphorescence signal in normal tissue in vivo compared with the BTP probe.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c3nr04349eDOI Listing
December 2013

In vivo type 2 cannabinoid receptor-targeted tumor optical imaging using a near infrared fluorescent probe.

Bioconjug Chem 2013 Nov 29;24(11):1907-16. Epub 2013 Oct 29.

Molecular Imaging Laboratory, Department of Radiology, University of Pittsburgh , Pittsburgh, Pennsylvania 15219, United States.

The type 2 cannabinoid receptor (CB2R) plays a vital role in carcinogenesis and progression and is emerging as a therapeutic target for cancers. However, the exact role of CB2R in cancer progression and therapy remains unclear. This has driven the increasing efforts to study CB2R and cancers using molecular imaging tools. In addition, many types of cancers overexpress CB2R, and the expression levels of CB2R appear to be associated with tumor aggressiveness. Such upregulation of the receptor in cancer cells provides opportunities for CB2R-targeted imaging with high contrast and for therapy with low side effects. In the present study, we report the first in vivo tumor-targeted optical imaging using a novel CB2R-targeted near-infrared probe. In vitro cell fluorescent imaging and a competitive binding assay indicated specific binding of NIR760-mbc94 to CB2R in CB2-mid delayed brain tumor (DBT) cells. NIR760-mbc94 also preferentially labeled CB2-mid DBT tumors in vivo, with a 3.7-fold tumor-to-normal contrast enhancement at 72 h postinjection, whereas the fluorescence signal from the tumors of the mice treated with NIR760 free dye was nearly at the background level at the same time point. SR144528, a CB2R competitor, significantly inhibited tumor uptake of NIR760-mbc94, indicating that NIR760-mbc94 binds to CB2R specifically. In summary, NIR760-mbc94 specifically binds to CB2R in vitro and in vivo and appears to be a promising molecular tool that may have great potential for use in diagnostic imaging of CB2R-positive cancers and therapeutic monitoring as well as in elucidating the role of CB2R in cancer progression and therapy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/bc400328mDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4177906PMC
November 2013

Apparent diffusion coefficient in normal and abnormal pattern of intervertebral lumbar discs: initial experience.

J Biomed Res 2011 05;25(3):197-203

Department of Diagnostic Radiology, the First Hospital of Medical School, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, China.

The aim of the present study was to compare the relationship of morphologically defined non-bulging/herniated, bulging and herniated intervertebral lumbar discs with quantitative apparent diffusion coefficient (ADC). Thirty-two healthy volunteers and 28 patients with back pain or sciatica were examined by MRI. All intervertebral lumbar discs from L1 to S1 were classified according to morphological abnormality and degenerated grades. The ADC values of nucleus pulposus (NP) were measured and recorded. The significant differences about mean ADC values of NP were found between non-bulging/herniated discs and bulging discs as well as herniated discs (P < 0.05), whereas there were no significant differences in ADC values between bulging and herniated discs (P > 0.05). Moreover, statistically significant relationship was found in the mean ADC values of NP between "non-bulging/herniated and non-degenerated discs" and "non-bulging/herniated degenerated discs" as well as herniated discs (P < 0.05). Linear regression analysis between ADC value and disc level revealed an inverse correlation (r = -0.18). The ADC map of the NP is a potentially useful tool for the quantitative assessment of componential and molecular alterations accompanied with lumbar disc abnormalities.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/S1674-8301(11)60026-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3597053PMC
May 2011

Cholesterol biosynthesis pathway intermediates and inhibitors regulate glucose-stimulated insulin secretion and secretory granule formation in pancreatic beta-cells.

Endocrinology 2010 Oct 4;151(10):4705-16. Epub 2010 Aug 4.

Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi 371-8512, Japan.

Cholesterol is reportedly abundant in the endocrine secretory granule (SG) membrane. In this study, we examined the involvement of cholesterol biosynthesis intermediates and inhibitors in insulin secretion and SG formation mechanisms. There are two routes for the supply of cholesterol to the cells: one via de novo biosynthesis and the other via low-density lipoprotein receptor-mediated endocytosis. We found that insulin secretion and content are diminished by β-hydroxy-β-methylglutaryl-coenzyme A inhibitor lovastatin but not by lipoprotein depletion from the culture medium in MIN6 β-cells. Cholesterol biosynthesis intermediates mevalonate, squalene, and geranylgeranyl pyrophosphate enhanced glucose-stimulated insulin secretion, and the former two increased insulin content. The glucose-stimulated insulin secretion-enhancing effect of geranylgeranyl pyrophosphate was also confirmed in perifusion with rat islets. Morphologically, mevalonate and squalene increased the population of SGs without affecting their size. In contrast, lovastatin increased the SG size with reduction of insulin-accumulating dense cores, leading to a decrease in insulin content. Furthermore, insulin was secreted in a constitutive manner, indicating disruption of regulated insulin secretion. Because secretogranin III, a cholesterol-binding SG-residential granin-family protein, coincides with SG localization based on the cholesterol composition, secretogranin III may be associated with insulin-accumulating mechanisms. Although the SG membrane exhibits a high cholesterol composition, we could not find detergent-resistant membrane regions using a lipid raft-residential protein flotillin and a fluorescent cholesterol-Si-pyrene probe as markers on a sucrose-density gradient fractionation. We suggest that the high cholesterol composition of SG membrane with 40-50 mol% is crucial for insulin secretion and SG formation functions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1210/en.2010-0623DOI Listing
October 2010

Phosphorescent light-emitting iridium complexes serve as a hypoxia-sensing probe for tumor imaging in living animals.

Cancer Res 2010 Jun 11;70(11):4490-8. Epub 2010 May 11.

Secretion Biology Laboratory, Institute for Molecular and Cellular Regulation and Division of Diagnostic Radiology and Nuclear Medicine, Graduate School of Medical Sciences, Gunma University, Maebashi, Japan.

Iridium complex is a promising organic light-emitting diode material for next generation video displays that emits phosphorescence quenched by oxygen. We used this oxygen-quenching feature for imaging tumor hypoxia. Red light-emitting Ir(btp)(2)(acac) (BTP) presented hypoxia-dependent light emission in culture cell lines, whose intensity was in parallel with hypoxia-inducible factor-1alpha images. BTP was further applied to imaging five nude mouse transplanted with tumors. All tumors presented a bright BTP-emitting image even 5 minutes after injection. The minimal image recognition size was approximately 2 mm in diameter. By morphologic examination and phosphorescence lifetime measurement, BTP appeared to localize to the tumor cells. Because BTP is easily modifiable, we synthesized BTP analogues with a longer excitation/emission wavelength. One of them, BTPHSA, depicted clear imaging from tumors transplanted 6 to 7 mm deep from the skin surface. We suggest that iridium complex materials have a vast potential for imaging hypoxic lesions such as tumor tissues.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1158/0008-5472.CAN-09-3948DOI Listing
June 2010