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.

Fluorescent and quantitative mitochondrial redox imaging of tumor targeted by Octa-RGD probe

Integrins,over-expressed in a broad range of cancer diseauses,are widely utilized as a tumor biomarker.Metabolism investigation also plays important roles in tumor theranostics.Devel-oping simple integrin-targetting probe and monitoring tumor metabolism will give opportunities to find ways for cancer treatment,however,the investigation of tumor metabolism with integrin receptor based probes has been rarely reported so far.Here,we developed an octavalent fuo-rescent probe Octa-R.GD by convenient genetic method,based on one tetrameric far-red fluo-rescent protein(fRFP)linked with RGD pept ides.We validated its inter gin targeting by confocal imaging in vitro.Then we screened a variety of tumor cells,and differentiated their binding affinity based on the fuorescence of the probe via flow cytometry.Among these cells,CNE-2 cells had the highest uptake of the probe,while B16 cells had the lowest,corresponding with their intergin expression levels.Next,the fuorescent and metabolic imaging was performed in HT1080(intergin postive)tumor,where nicotinamide adenine dinudeotide hydrogen(NADH),flavo-protein(Fp)and fRFP fuorescent signals were collected.The tumor from mice intravenously injected with Octa RGD probe displayed obviously higher NADH redox ratio NADH/(Fp+NADH)and fRFP signal,than those with fRFP protein.It suggested that integrin targeting may have influence on the target cell metabolism,and further demonstrated Octa-R.GD probe facilitated its uptake in the targeted tumor in vrivo.This paper developed a useful probe,which can bind integrins speci-cally and e±ciently in tumor cells,and together with tumor metabolic information,it may provide new insight for RGD targeting-based cancer therapeutics.

KillerRed protein based in vivo photodynamic therapy and corresponding tumor metabolic imaging

Photodynamic therapy(PDT)gains wide attention as a useful therapeutic method for cancer.It is mediated by the oxygen and photosensitizer under the specific light irradiation to produce the reactive oxygen species(ROS),which induce cellular toxicity and regulate the redox potential in tumor cells.Nowadays,genetic photosensitizers of low toxicity and easy production are required to be developed.KillerRed,a unique red fluorescent protein exhibiting excellent phototoxic properties,has the potential to act as a photosensitizer in the application of tumor PDT.Meantime,the course of tumor redox metabolism during this treatment was rarely investigated so far.Thus here,we investigated the effects of KillerRed-based PDT on tumor growth in vivo and examined the subsequent tumor metabolic states including the changes of nicotinamide adenine dinucleotide hydrogen(NADH)and flavoprotein(Fp),two important metabolic coenzymes of tumor cells.Results showed the tumor growth had been significantly inhibited by KillerRedbased PDT treatment compared to control groups.A home-made cryo-imaging redox scanner was used to measure intrinsic fluorescence and exogenous KillerRed fluorescence signals in tumors.The Fp signal was elevated by nearly 4.5-fold,while the NADH signal decreased by 66%after light irradiation,indicating that Fp and NADH were oxidized in the course of KillerRedbased PDT.Furthermore,we also observed correlation between the fluorescence distribution of KillerRed and NADH.It suggests that the KillerRed protein based PDT might provide a new approach for tumor therapy accompanied by altering tumor metabolism.

Visualizing DC morphology and T cell motility to characterize DC-T cell encounters in mouse lymph nodes under mTOR inhibition

Mammalian target of rapamycin(mTOR),a serine/threonine kinase orchestrating cellular metabolism,is a crucial immune system regulator.However,it remains unclear how mTOR regulates dendritic cell(DC) function in vivo,especially DC-T cell encounters,a critical step for initiating adaptive immune responses.We dynamically visualized DC-T contacts in mouse lymph node using confocal microscopy and established an encounter model to characterize the effect of mTOR inhibition on DC-T cell encounters using DC morphology.Quantitative data showed mTOR inhibition via rapamycin altered DC shape,with an increased form factor(30.17%) and decreased cellular surface area(20.36%) and perimeter(22.43%),which were associated with Cdc42 protein downregulation(52.71%).Additionally,DCs adopted a similar morphological change with Cdc42 inhibition via ZCL278 as that observed with mTOR inhibition.These morphologically altered DCs displayed low encounter rates with T cells.Time-lapse imaging data of T cell motility supported the simulated result of the encounter model,where antigen-specific T cells appeared to reduce arrest in the lymph nodes of rapamycin-pretreated mice relative to the untreated group.Therefore,mTOR inhibition altered DC morphology in vivo and decreased the DC-T cell encounter rate,as well as Cdc42 inhibition.By establishing an encounter model,our study provides an intuitive approach for the early prediction of DC function through morphological quantification of form factor and area.