Facile Whole-Body Imaging of Internal Fluorescent Tumors in Mice with an LED Flashlight

Yang, Meng; Luiken, George A.; Baranov, Eugene; Hoffman, Robert M.

doi:10.2144/05392bm02

Cited by 64 publications

(56 citation statements)

References 5 publications

(8 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…If the tumor mass is located in a deep layer, the excitation light for GFP may not be detected, therefore leading to a falsenegative result (39). To overcome this obstacle, a handheld flashlight to excite GFP fluorescence has been developed, which could detect signals from fluorescent proteins during surgery (40). For the application of this technology on clinical patients, supersensitive optical device that is able to capture signals from much deeper tissues is being explored and studied (41).…”

Section: Discussionmentioning

confidence: 99%

An Optimized Telomerase-Specific Lentivirus for Optical Imaging of Tumors

Yang

Liang

et al. 2010

Cancer Research

View full text Add to dashboard Cite

Advances in medical imaging techniques, such as ultrasound, computed tomography, magnetic resonance imaging, and positron emission tomography, have made great progress in detecting tumors. However, these imaging techniques are unable to differentiate malignant tumors from benign ones. Recently developed optical imaging of tumors in small animals provides a useful method to distinguish malignant tumors from their surrounding normal tissues. Human telomerase reverse transcriptase (hTERT) is normally inactivated in most somatic cells, whereas it is commonly reactivated in many cancer cells. In this study, we constructed a lentiviral vector that expresses green fluorescent protein (GFP) driven by an optimized hTERT promoter to create a noninvasive tumor-specific imaging methodology. The activity of this optimized hTERT promoter was found to be equal to the activity of SV40 and cytomegalovirus promoters. In vitro experiments showed that GFP was only expressed in telomerase-positive tumor cells infected with this lentivirus, whereas there was no GFP expression in telomerase-negative tumor cells or normal somatic cells. We also found that subcutaneous telomerasepositive tumors could be visualized 24 hours after an intratumoral injection with this lentivirus by using a charge-coupled device (CCD) camera. In contrast, telomerase-negative tumors could not be imaged after an intratumoral injection even for 30 days. These results suggest that infection with lentivirus containing this optimized hTERT promoter might be a useful diagnostic tool for the real-time visualization of macroscopically invisible tumor tissues using a highly sensitive CCD imaging system. Cancer Res; 70(7); 2585-94. ©2010 AACR.

show abstract

Section: Discussionmentioning

confidence: 99%

An Optimized Telomerase-Specific Lentivirus for Optical Imaging of Tumors

Yang

Liang

et al. 2010

Cancer Research

View full text Add to dashboard Cite

show abstract

“…The images were captured with a Nikon CoolPix P2 digital camera. A software program was used to calculate the number and intensity of pixels in each image and then convert the numbers to mm 2 for each tumor, as described by Yang et al 33 The fluorescence intensity is an average value of all detectable DsRed signals.…”

Section: Immunocytochemistrymentioning

confidence: 99%

Primary neural stem/progenitor cells expressing endostatin or cytochrome P450 for gene therapy of glioblastoma

et al. 2008

View full text Add to dashboard Cite

Despite recent technical improvements in surgical excision techniques and adjuvant radio-and chemotherapy, the clinical outcome of patients with grade IV astrocytoma (glioblastoma) remains very poor, with a median survival of less than 12 months. A promising approach to therapy employs gene-engineered neural stem/progenitor cells (NSCs) as a cellular therapeutic delivery system, to track glioblastoma cells and deliver anticancer molecules. However, most results on their tumor tropism have been derived by immortalized NSCs. We now report that primary murine gene-engineered NSCs displayed in vivo tropism for glioblastoma cells. Ten days after injection into the brain, many NSCs continued to express the transgene and the NSC marker, nestin. NSCs transduced with a retroviral vector co-expressing a secretable form of human endostatin and eGFP (NSC/endo-eGFP) released potentially antiangiogenetic concentrations of endostatin into the culture medium. Conditioned medium of NSC/endoeGFP cells inhibited the growth of mouse pulmonary microvascular endothelial cells (PMVECs). A good correlation between endostatin levels and PMVEC growth inhibition was observed. In NSCs co-expressing cytochrome P450 2B6 (CYP2B6) and eGFP (NSC/CYP2B6-eGFP), the forced expression of CYP2B6 resulted in intracellular activation of CPA and subsequent cell death. In the presence of NSC/CYP2B6-eGFP, we observed CPA cytotoxicity to DsRed-expressing U87Mg glioma cells. In vivo treatment of intracranial GL-261 glioblastoma with NSC/endo-eGFP caused a 65% reduction in tumor size, compared to untreated control mice or mice treated with NSC/eGFP cells. Our data suggest that primary NSCs transduced with retroviral vectors expressing endostatin and/or CYP2B6 have a potential role in glioblastoma therapy.

show abstract

“…Although some information is lost with whole-body imaging due to light scattering, a remarkable amount of information is obtained, even with such simple instrumentation. No skin autofluorescence was found due to the use of the proper excitation filter (8).…”

Section: Conceptsmentioning

confidence: 96%

Use of GFP for in vivo imaging: concepts and misconceptions

Hoffman

2008

Small Animal Whole-Body Optical Imaging Based on Genetically Engineered Probes

Self Cite

View full text Add to dashboard Cite

Although GFP and fluorescent proteins are used extensively for in vivo imaging, there are many misconceptions about GFP imaging especially compared to luciferase. GFP is not toxic, indeed, transgenic animals with GFP expressed in every cell (1) live as long as non-transgenic animals. Cancer cells with GFP are as aggressive and malignant as the cells without GFP (2-4). Cell lines can be made very bright with fluorescent proteins with no toxicity. The in vivo signal from fluorescent proteins is at least 1,000 times greater than luciferase (5). GFP is so bright that a single molecule of GFP can be seen in a bacterium (6). GFP can be observed through the skin on deep organs (7). Skin autofluorescence presents no problem for in vivo GFP imaging with proper filters (8). Fur can be rapidly clipped removing this autofluorescence (9). GFP is readily quantified by the image area which correlates to tumor volume (10). There are now numerous clones of GFP, RFP, YFP and proteins that change color (11) that can be used in vivo.

show abstract

Facile Whole-Body Imaging of Internal Fluorescent Tumors in Mice with an LED Flashlight

Cited by 64 publications

References 5 publications

An Optimized Telomerase-Specific Lentivirus for Optical Imaging of Tumors

An Optimized Telomerase-Specific Lentivirus for Optical Imaging of Tumors

Primary neural stem/progenitor cells expressing endostatin or cytochrome P450 for gene therapy of glioblastoma

Use of GFP for in vivo imaging: concepts and misconceptions

Contact Info

Product

Resources

About