新型染料IR-808靶向肿瘤近红外荧光成像的体内研究

目的 探讨近红外荧光染料IR-808在移植瘤动物模型中特异性的肿瘤靶向示踪作用。方法建立人肺癌细胞系NCI-H460、结肠癌细胞系HCT-116及鼠源肝癌细胞系Hepa 1-6皮下移植瘤裸小鼠模型,未接种癌细胞的裸小鼠作对照。尾静脉注射同等剂量染料IR-808,分别在不同时间点对裸小鼠正常组织及肿瘤组织进行近红外荧光成像,追踪染料在裸小鼠体内的分布,评价其肿瘤靶向作用。结果 在未接种的裸小鼠体内,IR-808染料首先在肝脏、心脏聚集,随后信号减弱,48h后基本代谢排出体外;在荷瘤裸小鼠模型体内,IR 808染料注入24h后开始靶向肿瘤,72h后荧光信号仍很稳定;取荷瘤裸小鼠组织进行近红外荧光成像,发现仅肿瘤组织有信号,其他组织无信号。全部实验小鼠状态良好,未见明显毒性反应。结论 近红外荧光染料IR 808能特异性靶向肿瘤成像,且信号稳定,无明显毒性,具有重要的应用前景     

荧光磁性纳米粒子与PSA单链抗体复合探针对前列腺癌的靶向显像和治疗

摘 要 目的: 研究荧光磁性纳米粒子与前列腺癌特异性抗原(prostate cancer specific antigen,PSA)单链抗体片段结合的复合纳米探针作为前列腺癌核磁共振靶向显像剂与治疗剂的可行性。方法：荧光磁性纳米粒子（FMCNPs）与前列腺癌特异性单链抗体片段(ScFv)桥联制备成复合纳米探针（FMCNPsScFv），应用高分辨电镜、荧光光谱仪与磁强度计进行鉴定。将FMCNPsScFv与前列腺癌LNCaP细胞共培养，观察其进入癌细胞的靶向性；采用MTT法评价复合纳米探针的细胞毒性。建立裸鼠前列腺癌细胞移植模型，进行免疫组化和病理学鉴定；荷前列腺癌裸鼠尾静脉注射复合纳米探针，采用荧光成像系统观察纳米探针在裸鼠体内的分布消除过程；利用核磁共振观察复合纳米探针肿瘤靶向显像效果；给予体外磁场照射(100 W功率)30 min,观察肿瘤体积的变化。结果：成功制备复合纳米探针FMCNPsScFv；细胞培养实验显示复合纳米探针能够进入前列腺癌细胞质；在显像浓度范围内复合纳米探针细胞毒性很低，不影响细胞增殖。成功制备裸鼠前列腺癌模型。荧光成像系统显示复合纳米探针快速地在裸鼠各重要器官分布，并逐渐集中于肿瘤部位；核磁共振显示纳米探针在24 h内能够清晰显示前列腺癌图像；体外磁场照射4 d后，注射复合纳米探针的裸鼠肿瘤组织生长显著慢于对照裸鼠的肿瘤组织（P<0.05）。结论：制备的复合纳米探针FMCNPsScFv能有效地靶向前列腺癌组织，可用于前列腺癌的核磁共振成像，也能用于体外磁场作用下的肿瘤治疗。     

188Re～HAb18F(ab′)2肝癌放射免疫显像的研究

目的　探讨1 88Re标记的肝癌单抗片段HAb18F(ab′) 2 在荷人肝癌移植瘤裸鼠体内的放免显像和生物学分布。方法　采用 2 巯基乙醇为还原剂的直接法标记肝癌单抗片段HAb18F(ab′) 2 ,Whatman 3mm纸层析法测 1 88Re HAb18F(ab′) 2 标记率 ,活细胞放射免疫结合法测标记物的免疫活性。放免显像实验时 ,于荷肝癌裸鼠尾静脉注射标记物 11 1MBq ,SPECT低能通用型准直器显像。生物学分布实验中每只荷肝癌裸鼠尾静脉注射标记物 1 85～ 2 5 9MBq ,分别于注射后不同时间点各处死一组 ,取血及主要组织 ,称重 ,测放射性计数。结果　最佳标记率为 91 7% ,免疫活性分数为 0 78。低能通用型准直器可缓解1 88Re显像时边界模糊的问题。在显像观察中 ,3h时右下肢肿瘤区已有放射性聚集 ,19h～ 30h时肿瘤显影清晰、明确 ,45h以后整体放射性均趋于减弱。生物学分布表明 ,标记物除在肿瘤中有特异性聚集外 ,在其他正常组织中无特异性浓聚 ,尤其在血液中清除较快 ,肿瘤最佳显像时间可确定为 2 0～ 30h。结论　1 88Re HAb18F(ab′) 2 在荷人肝癌裸鼠体内可明确地定位于肿瘤部位 ,为进一步研究该标记物的抑瘤作用奠定了基础     

靶向IL-11Rα的双标造影剂在乳腺癌成像中的实验研究

目的:对乳腺癌中IL-11Rα的表达进行非损伤性评价,探讨靶向IL-11Rα的双标造影剂在小鼠种植瘤模型中成像的特异性。方法:采用化学合成的方法合成IL-11的模拟物环九肽,并将其与与近红外染料或近红外/核素染料偶联,进而得到近红外或近红外/核素标记的靶向IL-11Rα的特异性造影剂;首先进行乳腺癌细胞MDA-MB-231的体外结合试验;然后通过建立乳腺癌裸鼠的异体移植瘤模型,进行体内光学成像以及核素成像试验,证实获得的成像化合物在体内试验中的特异性;分析证实获得的成像化合物在体内试验中的特异性;最后病理学检测裸鼠肿瘤标本。结果:体外细胞结合试验证明合成的近红外造影剂能够很好地与人乳腺癌细胞MDA-MB-231相结合。近红外光学成像和核成像均显示了肿瘤的高信号强度,光学成像与核成像结果一致。病理学分析结果证实光学信号较强的组织为乳腺癌组织。结论:靶向IL-11Rα的特异性造影剂可与IL-11Rα阳性的乳腺癌MDA-MB-231细胞特异性结合,并在裸鼠乳腺癌种植模型中进一步证明造影剂在体内成像中的肿瘤特异性,有望为临床肿瘤的早期分子诊断和靶向性治疗提供新的理论基础。     

99mTc-HL-91乏氧显像监测放疗前后肿瘤乏氧状态的动物实验研究

目的探讨^99mTc-HL-91乏氧显像在放疗中动态监测肿瘤乏氧状态的可行性。方法将10只荷人肺腺癌裸鼠在X线照射前后分别进行^99mTc-HL-91乏氧显像，进行图像的肉眼观察和注射显像剂1h、2h和4h的T／NT(肿瘤／非肿瘤)比较。结果X线照射后，肿瘤显示区域较照射前缩小。照射前，2h和4h的T／NT高于1h；照射后，4h时T／NT低于1h和2h。结论^99mTc-HL-91乏氧显像可以对荷瘤裸鼠肿瘤部位放疗过程中的乏氧状态进行动态监测，可能成为临床上无创监测放疗中肿瘤部位乏氧状态的有效方法。     

核素标记血管多肽显像诊断恶性肿瘤实验研究

[目的]以肿瘤血管系统为目的靶，以核素标记多肽ATWLPPR为显像剂，探讨核素标记肿瘤血管特异性多肽显像用于肿瘤诊断的可行性。[方法]应用^99mTc标记ATWLPPR并鉴定。制作荷人乳腺癌裸鼠模型，实验组于注射^99mTc-ATWLPPR后不同时间显像，对照组应用未标记ATWLPPR预处理后显像，勾画感兴趣区，计算两组肿瘤与对侧相应部位放射性比值。荷瘤裸鼠于注射显像剂后180min，取感兴趣器官及肿瘤组织称重并测量放射性计数。[结果]以HYNIC作为双功能螯合剂，^99mTc-HYNIC—ATWLPPR标记率可达91．53％±2．39％，放化纯为94．14％±1．75％，标志物体外稳定。实验组荷瘤裸鼠注射显像剂后180min肿瘤部位显影最为清晰，对照组肿瘤部位未见明显显像剂分布，两组肿瘤／对侧上肢的放射性比值分别为2．33±0．40和1．18±0．12（P〈0．05）。显像剂在荷乳腺癌裸鼠体内肝脏和肾脏的摄取最高，脑部摄取最低。[结论]制备的^99Tc-HYNIC-ATWLPPR方法简单，标记率和放化纯高、稳定性好，主要以肝脏和肾脏排泄，肿瘤组织可以对该品像剂特异忡格取辊示该显像剂可以用于肿瘤诊断．     

脐血间充质干细胞靶向胃癌移植瘤的实验研究

 目的　探讨脐血间充质干细胞靶向胃癌的可能性。方法　将胃癌细胞SGC-7901注射到裸鼠腹股沟皮下,建立胃癌裸鼠模型,荷胃癌小鼠随机分为脐血间充质干细胞组与成纤维细胞组,每组5只（n =5）。荧光染料SP-DiI染色人类脐血间充质干细胞及成纤维细胞,分组注射到对侧腹股沟皮下。10 d后处死裸鼠,取出肿瘤、注射部位、肝脏、脾脏和肺脏组织,连续切片分别制成冷冻切片和常规HE染色,荧光显微镜下观察冷冻切片中间充质干细胞和成纤维细胞在各组织中的分布。结果　脐血间充质干细胞在荷胃癌小鼠肿瘤部位中的荧光面积为（0.0150±0.0079）,注射点、肝脏、脾脏和肺脏组织中的荧光面积分别为（0.0043±0.0039）、（0.0010±0.0005）、（0.0015±0.0012）和（0.0014±0.0008）,肿瘤部位中的荧光面积与其他部位相比差异有统计学意义（P＜0.01）;成纤维细胞主要集中于注射点位置,在肿瘤组织、肝脏、脾脏和肺脏内均未发现它的存在,在两组裸鼠移植瘤中,脐血间充质干细胞的分布与成纤维细胞相比差异均有统计学意义（P＜0.01）。结论　人类脐血间充质干细胞能趋向到胃癌组织中,利用此特性可望将其作为载体应用到胃癌的诊断和治疗中。     

放射性碘-131在荷乳腺癌裸鼠体内分布与显像的实验研究

背景与目的近年发现约85%的雌激素受体阳性乳腺癌及其转移组织细胞表面存在大量碘转运体(sodium/iodidesymporter,NIS),可主动将血液中的碘转运到乳腺癌组织,其碘浓度远高于其他组织。本实验观察放射性131I在乳腺癌荷瘤裸鼠体内生物分布及核素显像,探讨131I对雌激素受体阳性乳腺癌的特异性亲和作用。方法制备MCF-7/ER(+)与MCF-7/ER(-)人乳腺癌裸鼠模型,当肿瘤长至0.8～1.0cm时腹腔注射131I37～55.5MBq,分别于注射后6、12、24h处死裸鼠,取血标本和心、肺、肝、肾、胃、小肠、肌肉、肿瘤组织,分别测量每克组织每分钟的放射性计数,计算每克组织摄取的放射性占总注入量的百分比(%ID/g)及肿瘤与非肿瘤组织之比(T/NT)。同时于不同时段对裸鼠行核素显像,观察131I在裸鼠体内的分布。结果注射131I后6hMCF-7/ER(+)组裸鼠肿瘤组织放射性浓度已较高,与MCF-7/ER(-)组相比有显著性差异(P<0.05),甲状腺、血液、肝脏、胃、肾放射性浓度也相对较高。12h时MCF-7/ER(+)组血、心、肺、小肠、肌肉的T/NT分别为2.39、3.06、3.94、7.69、7.60,24h时分别为5.15、5.47、5.29、11.44、10.99,而12h时放射性较高的肝、肾、胃T/NT也达到1.82、2.65、2.60。显像结果示12h时MCF-7/ER(+)裸鼠肿瘤部位可看到明显的放射性浓聚灶,24h仍可清     

131I标记抗人成骨肉瘤单抗荷瘤裸鼠体内分布和放射免疫显像研究

目的 :研究13 1I标记抗人成骨肉瘤单克隆抗体在荷人成骨肉瘤裸鼠体内分布和放射免疫定位显像。方法 :采用Iodogen固相法标记制备13 1I HOSMcAb。 2 5只荷瘤裸鼠随机分为 5组 ,分别腹腔注射13 1I HOSMcAb后 ,于6、12、2 4、48和 72h 5个时间段进行裸鼠的体内分布研究 ;对 5只荷瘤裸鼠分别腹腔注射13 1I HOSMcAb后 ,于 6、12、2 4、48和 72h 5个时间段进行荷瘤裸鼠的放射免疫定位显像研究。结果 :在荷人成骨肉瘤裸鼠腹腔注射13 1I HOSMcAb后 ,12h肿瘤与血的T/NT比值为1 3 7,2 4h为 3 75 ,48h达到最高为 5 2 4。腹腔注射13 1I HOSMcAb后 ,12h肿瘤部位即可见明显放射性浓聚 ,48h本底明显降低 ,肿瘤呈放射性热区。结论 :13 1I HOSMcAb对成骨肉瘤定向性较好 ,对放射免疫定位显像有利 ,为进一步放射免疫治疗研究提供了理论基础     

Preclinical evaluation of Mab CC188 for ovarian cancer imaging

Cancer stem cells (CSCs) have been successfully isolated from solid tumors and are believed to be initiating cells of primary, metastatic and recurrent tumors. Imaging and therapeutic reagents targeted to CSCs have potential to detect subclinical tumors and completely eradicate the disease. Previously, we have demonstrated that Mab CC188 binds to colon cancer CD133- and CD133+ (CSCs) cells. In this study, we examined the reactivity of Mab CC188 to ovarian cancer cells including CD133+ cells and primary tumor tissues using immunofluorescence staining methods and tissue microarray technique. We also explored the feasibility of using NIR dye-labeled Mab CC188 probe to image ovarian tumors in vivo. Mab CC188 stains both CD133- and CD133+ cells of ovarian cancer. Tissue microarray analysis reveals that 75% (92/123) of ovarian cancer cases are positively stained with Mab CC188. Weak positive (±), positive (+), strong positive (++) and very strong positive (+++) stains are 14.8, 3.7, 11 and 24.4%, respectively. In contrast, Mab CC188 staining is low in normal cells and tissues. In vivo study show that significant amounts of the probe accumulates in the excretion organs in the early period postinjection. At 24 hr, the imaging probes have largely accumulates in the tumor, while the intensity of the imaging probe decreases in the liver. The tumor uptake was still evident at 120-hr postinjection. Our work suggests that Mab CC188-based imaging and therapeutic reagents are capable of detecting early stage ovarian tumors and effectively treating the tumor.     

Targeted optical fluorescence imaging of human ovarian adenocarcinoma using a galactosyl serum albumin-conjugated fluorophore

Achieving maximal cytoreduction during surgery is a critical prognostic factor for women with advanced-stage ovarian cancer. Targeting optical imaging agents directly to ovarian cancer cells by attaching them to galactosyl (galactosamine-conjugated) serum albumin, whose sugar residues bind surface lectins that are expressed in certain ovarian adenocarcinomas, may improve metastatic tumor identification and resection. Thus, we sought to demonstrate that galactosyl serum albumin-conjugated fluorophores would be a robust mechanism through which to target ovarian cancer by evaluating its tumor-targeting capability in nine human ovarian adenocarcinoma cell lines. The optical fluorophore rhodamine green was conjugated to galactosyl serum albumin, a non-immunogenic targeting molecule. Galactosyl serum albumin–rhodamine green's ability to target nine human ovarian adenocarcinoma cell lines was evaluated by flow cytometry, fluorescence microscopy and in vivo optical fluorescence imaging using female athymic nu/nu mice. All nine cell lines tested bound galactosyl serum albumin–rhodamine green more effectively than non-glycosylated controls ( P <  0.0001). Fluorescence microscopy demonstrated that galactosyl serum albumin–rhodamine green was internalized into each cell line in a galactosamine-dependent manner. In vivo optical fluorescence images of intraperitoneal tumor-bearing mice acquired 3 h after intraperitoneal injection of galactosyl serum albumin–rhodamine green successfully differentiated between tumor and normal tissue. This technique also allowed the visualization of submillimeter-sized ovarian tumor implants. These results indicate that galactosyl serum albumin–rhodamine green can selectively target a variety of human ovarian adenocarcinomas for optical fluorescence imaging and thus may improve intraoperative tumor detection and resection. ( Cancer Sci 2007; 98: 1727–1733)     

Image-guided enzyme/prodrug cancer therapy.

PURPOSE: The success of enzyme/prodrug cancer therapy is limited by the uncertainty in the delivery of the enzyme in vivo. This study shows the use of noninvasive magnetic resonance (MR) and optical imaging to image the delivery of a prodrug enzyme. With this capability, prodrug administration can be timed so that the enzyme concentration is high in the tumor and low in systemic circulation and normal tissue, thereby minimizing systemic toxicity without compromising therapeutic efficiency. EXPERIMENTAL DESIGN: The delivery of a multimodal imaging reporter functionalized prodrug enzyme, cytosine deaminase, was detected by MR and optical imaging in MDA-MB-231 breast cancer xenografts. Stability of the enzyme in the tumor was verified by (19)F MR spectroscopy, which detected conversion of 5-fluorocytosine to 5-flurouracil. The optimal time window for prodrug injection determined by imaging was validated by immunohistochemical, biodistribution, and high-performance liquid chromatographic studies. The therapeutic effect and systemic toxicity of this treatment strategy were investigated by histologic studies and tumor/body weight growth curves. RESULTS: The delivery of the functionalized enzyme in tumors was successfully imaged in vivo. The optimal time window for prodrug administration was determined to be 24 h, at which time the enzyme continued to show high enzymatic stability in tumors but was biodegraded in the liver. Significant tumor growth delay with tolerable systemic toxicity was observed when the prodrug was injected 24 h after the enzyme. CONCLUSION: These preclinical studies show the feasibility of using a MR-detectable prodrug enzyme to time prodrug administration in enzyme/prodrug cancer therapy.     

Near infrared thoracoscopy of tumoral protease activity for improved detection of peripheral lung cancer

Improvement in tumor detection using "smart" probes in combination with microcatheter fluorescence thoracoscopy was evaluated in a mouse model. These imaging probes increase in fluorescence intensity after protease activation; cathepsin B is a major activator of the probes used in this study. Lewis lung carcinoma cells were orthotopically implanted in the subpleural lung parenchyma. Two activatable near infrared (NIR) probes with different excitation and emission wavelength were administered intravenously to determine whether wavelength would modulate target to background ratio (TBR). Mice were selectively intubated and thoracoscopy performed. A 0.8 mm outer diameter imaging catheter was used to record simultaneous white-light (anatomic) and NIR (protease expression) images. At both wavelength pairs evaluated (680/700 and 750/780 nm excitation/emission), the intrinsic luminosity differences between tumors and normal lung in uninjected animals was low (p > 0.3 and p = 0.4, respectively and TBR near 1). In mice receiving protease probes IV, tumors were significantly more fluorescent than adjacent lung (p < 0.0005 for 680/700 and p < 0.006 for 750/780) and TBR increased to approximately 9-fold. Confirmatory fluorescence microscopy and immunohistochemistry were similar and revealed that normal lung had very low levels when compared to tumors of cathepsin B and probe fluorescence. In conclusion, protease sensitive imaging probes selective for cathepsin B, imaged with NIR microcatheters, significantly increase the TBR, making small peripheral lung tumors more readily apparent. Such an approach may be a useful adjunct in staging or restaging patients with lung cancer to find minimal disease in the pleural and subpleural space.     

Blood-based screening and light based imaging for the early detection and monitoring of ovarian cancer xenografts

We report a novel technology for in vivo early detection, identification, and monitoring of ovarian cancer in live mice leading to better treatment outcome. A genetic dualistic reporter system that uses an adenoviral (Ad) vector to transfer the genetic reporters to the ovarian cancer is described. Infection of the cancer cells leads to expression of one reporter that is detected in blood, namely, secreted human placental alkaline phosphatase (SEAP). A second reporter, namely, enhanced green fluorescent protein (GFP) is also delivered by the Ad, leading to expression at the site of ovarian cancer. The SEAP gene under control of the cytomegalovirus (CMV) promoter element is linked to the GFP gene with an IRES element. A diagnostic adenoviral vector (Ad) encoding the SEAP and GFP (Ad5-SEAP-GFP) is produced. Efficacy of newly developed diagnostic vector is tested in cell culture and animal models. SKOV3ip.1 cells are infected with Ad5-SEAP-GFP. Over time the cells are monitored for fluorescence and SEAP is also measured in the growth media supernatant. For animal experiments, SKOV3ip.1 cells are implanted first in nude mice either subcutaneously (SC) or intraperitoneally (IP) separately. After 4-7 days, the Ad5-SEAP-GFP is administered. Control mice do not receive any Ad vector. All mice are imaged with a fluorescent stereomicroscope after 24 h, and blood is collected for SEAP analyses. Increasing green fluorescence is detected in all SKOV3ip.1 cells infected with Ad5-SEAP-GFP, while SEAP levels in growth media increase over monitoring period. Expression of GFP in both SC and IP tumors is detected by 24 h in the live mice. At this time, the SEAP blood levels are more than 2-3 fold greater than blood levels of control group. GFP fluorescence and SEAP levels continue to increase in all mice that are injected with Ad5-SEAP-GFP until termination. Control mice (both SC and IP) do not express GFP or SEAP throughout the experiment. GFP contrast is necessary to differentiate between micro-sized early stage non-palpable ovarian tumor nodules and surrounding normal tissue. While the studies are conducted in mice, it is envisioned that the dual-based approach will eventually be translated into human applications for routine diagnosis and monitoring of ovarian cancer when an ovarian cancer specific promoter will be available. Due to the thickness of the abdominal wall in human laparoscopy or laparotomy will be necessary. This system will provide gynecologic oncologists with a more effective tool for treating patients. The blood-based screening assay provides a quick test to determine the presence of the ovarian cancer at its earliest stage. The location of the ovarian cancer is afforded by the light-based imaging component, which represents a new and improving technology with tremendous advantages of sensitivity and spatial resolution to localize micro-sized tumor nodules. The novelty of the dualistic system is the linkage of blood-based reporter screening as a selection criteria for subsequent light-based imaging procedures. This combination will lead to an accurate and widely applicable method for the early detection and monitoring of ovarian cancer, especially in high-risk women     

Imaging epidermal growth factor receptor expression in vivo: pharmacokinetic and biodistribution characterization of a bioconjugated quantum dot nanoprobe.

PURPOSE: To develop and validate an optical imaging nanoprobe for the discrimination of epidermal growth factor (EGF) receptor (EGFR)-overexpressing tumors from surrounding normal tissues that also expresses EGFR. EXPERIMENTAL DESIGN: Near-infrared (NIR) quantum dots (QD) were coupled to EGF using thiol-maleimide conjugation to create EGF-QD nanoprobes. In vitro binding affinity of these nanoprobes and unconjugated QDs was evaluated in a panel of cell lines, with and without anti-EGFR antibody pretreatment. Serial optical imaging of HCT116 xenograft tumors was done after systemic injection of QD and EGF-QD. RESULTS: EGF-QD showed EGFR-specific binding in vitro. In vivo imaging showed three distinct phases, tumor influx ( approximately 3 min), clearance ( approximately 60 min), and accumulation (1-6 h), of EGF-QD nanoprobes. Both QD and EGF-QD showed comparable nonspecific rapid tumor influx and clearance followed by attainment of an apparent dynamic equilibrium at approximately 60 min. Subsequently (1-6 h), whereas QD concentration gradually decreased in tumors, EGF-QDs progressively accumulated in tumors. On delayed imaging at 24 h, tumor fluorescence decreased to near-baseline levels for both QD and EGF-QD. Ex vivo whole-organ fluorescence, tissue homogenate fluorescence, and confocal microscopic analyses confirmed tumor-specific accumulation of EGF-QD at 4 h. Immunofluorescence images showed diffuse colocalization of EGF-QD fluorescence within EGFR-expressing tumor parenchyma compared with patchy perivascular sequestration of QD. CONCLUSION: These results represent the first pharmacokinetic characterization of a robust EGFR imaging nanoprobe. The measurable contrast enhancement of tumors 4 h after systemic administration of EGF-QD and its subsequent normalization at 24 h imply that this nanoprobe may permit quantifiable and repetitive imaging of EGFR expression.     

Selective enrichment of hypericin in malignant glioma: pioneering in vivo results

Malignant gliomas are diffuse infiltrative growing tumors with a poor prognosis despite treatment with a combination of surgery, radiotherapy and chemotherapy. It has been shown recently that complete tumor resection improves the survival time significantly. Hypericin, a component of St. Johns Wort, is one of the most powerful photosensitizers in nature. The aim of the present study was to investigate accumulation of hypericin in intracerebral implanted malignant glioma in vivo. Rats underwent stereotactic implantation of C6 glioma cells. After intravenous administration of hypericin (5 mg per kg body weight), accumulation of the compound was studied in tumor, the infiltration zone surrounding the tumor and healthy brain (contralateral hemisphere) by fluorescence microscopy between 0 and 48 h after injection. Results were compared by one-way analysis of variance. For post hoc pair-wise comparison the Tukey-Kramer HSD test was used. Accumulation of hypericin was significantly higher in C6 glioma as compared to normal tissue. Maximum hypericin uptake was achieved at 24 h after injection. Ratios of fluorescence intensity between tumor and normal tissue as well as infiltration zone and normal tissue of about 6.1:1 and 1.4:1 were found. Considering tissue auto-fluorescence, fluorescence ratios of about 19.8:1 and 2.5:1 were calculated, respectively. Therefore, hypericin seems to be quite an effective fluorescence marker for the detection of glioma in vivo. To the best of our knowledge, the present study demonstrates for the first time that hypericin accumulates selectively in intracerebral implanted C6 glioma in vivo after systemic (intravenous) administration.     

In vivo Molecular targeting effects of anti-Sp17- ICG-Der-02 on hepatocellular carcinoma evaluated by an optical imaging system

Background

As the expression of human sperm protein 17 (Sp17) in normal tissue is limited and the function is obscure, its aberrant expression in malignant tumors makes it to be a candidated molecular marker for tumor imaging diagnosis and targeting therapy of the diseases.The aim of this research is to evaluate the targeting effects of anti-sperm protein 17 monoclonal antibody (anti-Sp17) on cancer in vivo and investigate its usefulness as a reagent for molecular imaging diagnosis.

Methods

Immunohistochemistry was used to identify the expression of Sp17 in a hepatocellular carcinoma cell line and tumor xenograft specimens. A near infrared fluorescence dye, ICG-Der-02, was covalently linked to anti-Sp17 for in vivo imaging. The immuno-activity of the anti-Sp17-ICG-Der-02 complex was tested in vitro by ELISA; it was then injected into tumor-bearing nude mice through the caudal vein to evaluate its tumor targeting effect by near infrared imaging system.

Results

Overexpression of Sp17 on the surface of the hepatocellular carcinoma cell line SMMC-7721 was demonstrated. Anti-Sp17-ICG-Der-02 with immuno-activity was successfully synthesized. The immuno-activity and photo stability of anti-Sp17- ICG-Der-02 showed good targeting capability for Sp17 expressing tumor models (SMMC-7721) in vivo, and its accumulation in the tumor lasted for at least 7 days.

Conclusions

Anti-Sp17 antibody targeted and accumulated in Sp17 positive tumors in vivo, which demonstrated its capability of serving as a diagnostic reagent.     

Near-infrared optical imaging of epidermal growth factor receptor in breast cancer xenografts

The specificity of a novel epidermal growth factor (EGF)-Cy5.5 fluorescent optical probe in the detection of EGF receptor (EGFr) was assessed using continuous-wave fluorescence imaging accomplished via an intensified charge-coupled device (CCD) camera. Human mammary MDA-MB-468 (EGFr+) and MDA-MB-435 (EGFr-) cancer cells were incubated with Cy5.5, EGF-Cy5.5, or the anti-EGFr monoclonal antibody C225 or EGF followed by EGF-Cy5.5 and examined under a fluorescence microscope. In vivo imaging was performed on mice with s.c. MDA-MB-468 and MDA-MB-435 tumors. Images were obtained every 6 s for 20 min after i.v. injection of each agent and every 24 h after injection for up to 192 h. Additionally, mice with MDA-MB-468 tumors were injected i.v. with C225 24 h before injection of EGF-Cy5.5. EGF-Cy5.5, but not Cy5.5 or indocyanine green dye (ICG), bound to MDA-MB-468 cells. Binding of EGF-Cy5.5 was blocked by C225 and by EGF. In contrast, binding of EGF-Cy5.5 to MDA-MB-435 cells was not observed. Monitoring of the time-fluorescence intensity in mice confirmed that ICG and Cy5.5 had no favorable binding to tumor regardless of EGFr expression level. In contrast, EGF-Cy5.5 accumulated only in MDA-MB-468 tumors. Moreover, tumor uptake of EGF-Cy5.5 was blocked by C225. ICG and Cy5.5 fluorescence was completely absent from the tumor site, regardless of EGFr expression level, 24 h after injection. Little EGF-Cy5.5 fluorescence was detected in MDA-MB-435 tumors 24 h after injection. In MDA-MB-468 tumors, our data suggest that EGF-Cy5.5 may be used as a specific NIR contrast agent for noninvasive imaging of EGFr expression and monitoring of responses to molecularly targeted therapy.