VISUALIZATION OF HEAD AND NECK CANCER MODELS WITH A TRIPLE FUSION REPORTER GENE

The development of experimental animal models for head and neck tumors generally rely on the biol uminescence imaging to achieve the dynamic monitoring of the tumor growth and metastasis due to the complicated anatomical structures.Since the bioluminescence imaging is largely affected by the intracellular luciferase expression level and external D-luciferin concentrations,its imaging accuracy requires further confirmation.Here,a new triple fusion reportelr gene,which consists of a herpes simplex virus type 1 thymidine kinase(TK)gene for radioactive imaging,a far-red fuorescent protein(mLumin)gene for fuorescent imaging,and a firefly luciferase gene for bioluminescence imaging,was introduced for in vrivo observation of the head and neck tumors through multi-modality imaging.Results show that fuorescence and bioluminescence signals from mLumin and luciferase,respectively,were clearly observed in tumor cells,and TK could activate suicide pathway of the cells in the presence of nucleotide analog-ganciclovir(GCV),demonstrating the effecti veness of individual functions of each gene.Moreover,subcutaneous and metastasis animal models for head and neck tumors using the fusion reporter gene-expressing cell lines were established,allowing multi-modality imaging in vio.Together,the established tumor models of head and neck cancer based on the newly developed triple fusion reporter gene are ideal for monitoring tumor growth,assessing the drug therapeutic efficacy and verifying the effec-tiveness of new treatments.

Imaging pancreatobiliary ductal system with optical coherence tomography: A review

An accurate, noninvasive and cost-effective method of in situ tissue evaluation during endoscopy would be highly advantageous for the detection of dysplasia or early cancer and for identifying different disease stages. Optical coherence tomography(OCT) is a noninvasive, high-resolution(1-10 μm) emerging optical imaging method with potential for identifying microscopic subsurface features in the pancreatic and biliary ductal system. Tissue microstructure of pancreaticobiliary ductal system has been successfully imaged by inserting an OCT probe through a standard endoscope operative channel. High-resolution OCT images and the technique's endoscopic compatibility have allowed for the microstructural diagnostic of thepancreatobiliary diseases. In this review, we discussed currently available pancreaticobiliary ductal imaging systems to assess the pancreatobiliary tissue microstructure and to evaluate varieties of pancreaticobiliary disorders and diseases. Results show that OCT can improve the quality of images of pancreatobiliary system during endoscopic retrograde cholangiopancheatography procedure, which may be important in distinguishing between the neoplastic and non-neoplastic lesions.

QUANTIFYING NANOP ARTICLE TRANSPORT IN VIVO USING HYP ERSPECTRAL IMA GING WITH A DORSAL SKINFOLD WINDOW CHAMBER

We have developed a noninv asive imaging method to quantify in viwo drug delivery pharmaco-kinetics without the need for blood or tissue collection to determine drug concentration.By combining the techniques of hy perspectral imaging and a dorsal skinfold window chamber,this method enabled the real-time monitoring of vascular transport and tissue deposition of nano-particles labeled with near infrared(NIR)dye.Using this imaging method,we quantified the delivery pharmacokinetics of the native high-density lipoprotein(HDL)and epidermal growth factor receptor(EGFR)-targeted HDL nanoparticles and demonstrated these HDLs had long circulation time in blood stream(half-life>12h).These HDL nanoparticles could eficiently carry cargo DiR-BOA to extravasate from blood vesels,difuse through extr acellular matrix,and penetrate and be retained in the tumor site.The EGFR targeting specificity of EGFR-targeted HDL(EGFR-specific peptide conjugated HDL)was also visualized in vivo by competitive inhi bition with excess EGFR specifc peptide.In summary,this imaging technology may help point the way toward the development of novel imaging based pharmacokinetic assays for preclinical drugs and evaluation of drug delivery eficiency,providing a dynamic window into the devel opment and application of novel drug delivery systems.

IN VIVO NEAR-INFRAREDFLUORESCENCEIMAGING OF HUMANCOLONADENOCARCINOMABY SPECIFIC IMMUNOTARGETINGOFA TUMOR-ASSOCIATEDMUCIN

Background and Aims: Accurate endoscopic detection of premalignant lesions and earlycancers in the colon is essential for cure, since prognosis is closely related to lesion size andstage. Although it has great clinical potential, autofluorescence endoscopy has limited tumorto-normal tissue image contrast for detecting small preneoplastic lesions. We have developed amolecularly specific, near-infrared fluorescent monoclonal antibody (CC49) bioconjugate whichtargets tumor-associated glycoprotein 72 (TAG72), as a contrast agent to improve fluorescencebased endoscopy of colon cancer. Methods: The fluorescent anti-TAG72 conjugate was evaluated in vitro and in vivo in athymic nude mice bearing human colon adenocarcinoma (LS174T)subcutaneous tumors. Autofluorescence, a fluorescent but irrelevant antibody and the free fluorescent dye served as controls. Fluorescent agents were injected intravenously, and in vivowhole body fluorescence imaging was performed at various time points to determine pharmacokinetics, followed by ex vivo tissue analysis by confocal fluorescence microscopy and histology Results: Fluorescence microscopy and histology confirmed specific LS174T cell membrane targeting of labeled CC49 in vitro and ex vivo. In vivo fluorescence imaging demonstrated significant tumor-to-normal tissue contrast enhancement with labeled-CC49 at three hours postinjection, with maximum contrast after 48 h. Accumulation of tumor fluorescence demonstratedthat modification of CC49 antibodies did not alter their specific tumor-localizing properties, andwas antibody-dependent since controls did not produce detectable tumor fluorescence. Conclusions: These results show proof-of-principle that our near-infrared fluorescent-antibody probetargeting a tumor-associated mucin detects colonic tumors at the molecular level in real time,and offer a basis for future improvement of image contrast during clinical fluorescence endoscopy.

MICROENDOSCOPIC SPECTRAL IMAGING AS A TOOL FOR SMALL DUCTUAL DIAGNOSTICS:PRELIMINARY EXPERIENCE

A technical feasibility of autofluorescence ductoscopy in breast milk ducts as blood vessels phantoms has been assessed as successful.Malignant tumor can be clearly identified through the milk ducts.We also present the operation principle as well as the preliminary experimental results of a new type of microsize multicorefiber that enables imaging through blood vessel phantoms.Imaging of a manipulated microwire through a drilled phantom is presented.