Epidermal growth factor receptor and its inhibition in radiotherapy: in vivo findings

Increasing evidence shows that dysregulated epidermal growth factor receptor (EGFR) signalling plays an important part in neoplasia. When over expressed or mutated, EGFR is frequently associated with more aggressive tumour growth, poor patient prognosis and resistance of tumours to cytotoxic agents, including radiation. The present studies with murine carcinomas showed that there is an inverse correlation between the level of EGFR and tumour radiocurability. Likewise, the present clinical study in patients with head and neck cancer shows that EGFR over expression correlates with poorer tumour response to radiotherapy. Adding EGFR to tumour cells in vitro protected cells against the cytotoxic action of radiation, whereas blocking EGFR with anti-EGFR antibodies enhanced cell radiosensitivity. A casual relationship between EGFR and increased cellular resistance to radiation was established by transferring the EGFR gene into low EGFR-expressing radiosensitive tumour cells, which then become radioresistant. Radiation activated EGFR and its downstream signalling pathways in radioresistant but not in radiosensitive tumours, and this effect was associated with increased resistance to radiation, and enhanced repopulation in irradiated tumours. Increasing evidence shows that blockage of EGFR or interference with any of the steps in its signal transduction cascade can counteract negative outcomes of EGFR signalling, which has recently been explored as a therapeutic strategy in cancer treatment. The present findings demonstrate that treatment of human tumour xenografts with C225, an anti-EGFR monoclonal antibody, dramatically enhanced tumour response to radiation. Overall, the findings show that over expression of EGFR may serve as a predictor of tumour treatment outcome by radiotherapy and as a therapeutic target to enhance the efficacy of radiotherapy.     

Epidermal growth factor receptor and its inhibition in radiotherapy: in vivo findings

Increasing evidence shows that dysregulated epidermal growth factor receptor (EGFR) signalling plays an important part in neoplasia. When over expressed or mutated, EGFR is frequently associated with more aggressive tumour growth, poor patient prognosis and resistance of tumours to cytotoxic agents, including radiation. The present studies with murine carcinomas showed that there is an inverse correlation between the level of EGFR and tumour radiocurability. Likewise, the present clinical study in patients with head and neck cancer shows that EGFR over expression correlates with poorer tumour response to radiotherapy. Adding EGFR to tumour cells in vitro protected cells against the cytotoxic action of radiation, whereas blocking EGFR with anti‐EGFR antibodies enhanced cell radiosensitivity. A casual relationship between EGFR and increased cellular resistance to radiation was established by transferring the EGFR gene into low EGFR‐expressing radiosensitive tumour cells, which then become radioresistant. Radiation activated EGFR and its downstream signalling pathways in radioresistant but not in radiosensitive tumours, and this effect was associated with increased resistance to radiation, and enhanced repopulation in irradiated tumours. Increasing evidence shows that blockage of EGFR or interference with any of the steps in its signal transduction cascade can counteract negative outcomes of EGFR signalling, which has recently been explored as a therapeutic strategy in cancer treatment. The present findings demonstrate that treatment of human tumour xenografts with C225, an anti‐EGFR monoclonal antibody, dramatically enhanced tumour response to radiation. Overall, the findings show that over expression of EGFR may serve as a predictor of tumour treatment outcome by radiotherapy and as a therapeutic target to enhance the efficacy of radiotherapy.     

Antitumor effects and normal tissue toxicity of 111In-labeled epidermal growth factor administered to athymic mice bearing epidermal growth factor receptor-positive human breast cancer xenografts.

The epidermal growth factor receptor (EGFR) is an attractive target for the design of radiotherapeutic agents for breast cancer because it is present on almost all estrogen receptor-negative, hormone-resistant tumors with a poor prognosis. In this study, we describe the antitumor effects and normal tissue toxicity of the novel Auger electron-emitting radiopharmaceutical (111)In-labeled diethylenetriaminepentaacetic acid-human epidermal growth factor ((111)In-DTPA-hEGF) administered to athymic mice bearing EGFR-positive human breast cancer xenografts. METHODS: Mice bearing subcutaneous MDA-MB-468 or MCF-7 human breast cancer xenografts were treated with 5 weekly doses of (111)In-DTPA-hEGF (total, 27.7-92.5 MBq or 5-17 micro g). Treatment was commenced 6 wk after tumor cell implantation (established tumors) or 1 wk after implantation (nonestablished tumors). Antitumor effects were assessed by use of the slope of the tumor growth curve. Normal tissue toxicity was assessed by use of plasma alanine transaminase and creatinine levels, hematologic indices (leukocytes, platelets, erythrocytes, and hemoglobin), histopathologic examination of the liver and kidneys, and changes in body weight. The uptake of (111)In-DTPA-hEGF in tumors of different sizes (<5-200 mm(3)) was investigated, and microdosimetry estimates were calculated. RESULTS: (111)In-DTPA-hEGF exhibited strong antitumor effects against established MDA-MB-468 xenografts, decreasing their growth rate 3-fold compared with that in normal saline-treated mice (slopes, 0.0225 and 0.0737 d(-1), respectively; P = 0.002). The antitumor effects of (111)In-DTPA-hEGF were much more profound in mice with small, nonestablished MDA-MB-468 tumors, which regressed, than in saline-treated mice (slopes, -0.009 and 0.0297 d(-1), respectively; P < 0.001). The growth of MCF-7 xenografts, with a 100-fold-lower level of EGFR expression, was modestly inhibited by (111)In-DTPA-hEGF compared with that in saline-treated mice (slopes, 0.0250 and 0.0488 d(-1), respectively; P = 0.051). There was a 1.4- to 2-fold decrease in leukocyte and platelet counts with (111)In-DTPA-hEGF treatment, but these counts remained in the normal ranges. There was no change in other biochemical or hematologic parameters or body weight. There was no evidence of morphologic damage to the liver or kidneys. A strong inverse relationship was observed between radiopharmaceutical uptake and tumor size, with small tumors (<5 mm(3)) accumulating >30% of the injected dose (%ID) per gram, compared with 5 %ID/g for tumors measuring 6-30 mm(3). Exceptionally high uptake (>80 %ID/g) was achieved in tumors measuring 1-2 mm(3). Microdosimetry estimates indicated that the nucleus of an MDA-MB-468 cell would receive 90-1,400 cGy, depending on the level of radiopharmaceutical uptake. CONCLUSION: (111)In-DTPA-hEGF exhibited strong antitumor effects against MDA-MB-468 breast cancer xenografts overexpressing EGFR. The highest tumor localization, radiation-absorbed doses, and growth inhibition were achieved for small, nonestablished tumors, suggesting that the radiopharmaceutical may be most valuable for the treatment of small-volume metastatic breast cancer or occult micrometastases in an adjuvant setting.     

血管内皮生长因子在胃癌中的 表达及其临床意义

目的探讨胃癌中人表皮生长因子受体2(human epidermal growth factor receptor 2,HER2)和血管内皮生长因子(vascular endothelial growth factor,VEGF)的表达与胃癌的发生、发展的关系,及作为分子靶点指导胃癌患者临床用药的意义。方法采用免疫组化(immunohistochemistry,IHC)的方法检测103例胃癌患者HER2及VEGF的状态,同时联合荧光原位杂交的方法检测HER2的状态,并与患者的临床资料进行相关性分析。结果①胃癌中HER2扩增率约为11%(11/103),在阳性病例中IHC与荧光原位杂交(fluorescentin situ hydridization,FISH)方法的符合率为90%,具有相关性(P<0.01);②HER2的扩增与胃癌的病理分级、淋巴结转移与否及Lauren分型相关(P<0.05);③胃癌中VEGF表达阳性率约为24%(25/103),VEGF的阳性表达与肿瘤的浸润深度、病理分级、Lauren分型相关(P<0.05);④HER2的表达与VEGF的表达不相关(P>0.05)。结论 HER2、VEGF的阳性表达与胃癌特别是分化较好的胃管状腺癌的发生、发展密切相关。联合检测HER2及VEGF在胃癌(特别是肠型胃癌)中的表达对了解胃癌的发生、发展,及靶向药物曲妥珠单抗和贝伐单抗的选择具有重要意义。     

复方消溃灵对消化性溃疡及萎缩性胃炎患者EGF与EGFR的影响

 目的探讨中药复方消溃灵对消化性溃疡及萎缩性胃炎患者血清、胃液EGF含量及胃粘膜EGFR表达的影响.方法采用放射免疫法及SABC免疫组化技术对24例消化性溃疡和27例萎缩性胃炎及12例"正常"胃粘膜者血清、胃液EGF含量及胃粘膜EGFR进行检测.结果治疗前,EGF含量,PU组明显低于对照组(P＜0.05),AG组显著高于对照组(P＜0.01),EGFR表达,PU组及AG组均较对照组增强(P＜0.05,p＜0.01);EGF含量及EGFR表达与治疗前比较,PU组变化显著(P＜0.01),AG组无明显差异(P＞0.05).结论消溃灵可显著提高消化性溃疡患者血清及胃液EGF含量并促进胃粘膜EGFR表达,对萎缩性胃炎患者无明显影响.     

A kit formulated under good manufacturing practices for labeling human epidermal growth factor with 111In for radiotherapeutic applications.

Our goal was to design and manufacture a kit under good manufacturing practices (GMP) for the preparation of (111)In-DTPA-hEGF Injection, a novel targeted radiotherapeutic agent for advanced epidermal growth factor receptor (EGFR)-positive breast cancer. METHODS: Human EGF (hEGF) was derivatized with diethylenetriaminepentaacetic acid (DTPA) and then purified by size-exclusion chromatography and ultrafiltration. Kits were prepared by dispensing 0.25 mg (1 mL) of DTPA-hEGF in 1 mol/L sodium acetate buffer [pH 6.0] into single-dose glass vials. Raw materials were pharmacopoieal or reagent grade according to the American Chemical Society and were tested for identity and purity. Kits were tested for protein concentration, purity and homogeneity (sodium dodecyl sulfate polyacrylamide gel electrophoresis and size-exclusion high-performance liquid chromatography), pH, clarity and color, volume, DTPA substitution, labeling efficiency, receptor binding to MDA-MB-468 human breast cancer cells, and sterility and apyrogenicity. (111)In-DTPA-hEGF Injection was tested for pH, radionuclidic and radiochemical purity, clarity and color, and sterility and apyrogenicity. RESULTS: Four lots of kits and 8 lots of (111)In-DTPA-hEGF Injection passed all quality specifications. The labeling efficiency was 94%-99% with 115-773 MBq (111)In chloride added to a single kit. (111)In-DTPA-hEGF exhibited preserved receptor binding against MDA-MB-468 cells (affinity constant [K(a)], 0.9-1.1 x 10(7) L/mol; maximum number of binding sites per cell [B(max)], 1.1-2.2 x 10(6) sites per cell). In addition, labeling of aliquots of the kit suggested that a single vial could be labeled with up to 3,083 MBq (111)In while maintaining a radiochemical purity of >90%. Kits were stable for >90 d and (111)In-DTPA-hEGF Injection was stable for >24 h stored at 4 degrees C. CONCLUSION: The kit formulation is suitable for preparing (111)In-DTPA-hEGF Injection for a phase I clinical trial in patients with advanced EGFR-positive breast cancer. Establishment of the GMP processes for (111)In-DTPA-hEGF Injection provides a useful example of manufacturing biotechnology-based investigational radiopharmaceuticals in an academic environment for early phase I clinical trials.     

Dual-labeled trastuzumab-based imaging agent for the detection of human epidermal growth factor receptor 2 overexpression in breast cancer.

Overexpression of the human epidermal growth factor receptor (HER) family has been implicated in cancer because of its participation in signaling pathways regulating cellular proliferation, differentiation, motility, and survival. In this work, we exploited the extracellular binding property of trastuzumab, a clinically therapeutic monoclonal antibody to the second member of the HER family (HER2), to design a diagnostic imaging agent, ((111)In-DTPA)(n)-trastuzumab-(IRDye 800CW)(m), that is dual labeled with (111)In, a gamma-emitter, and a near-infrared (NIR) fluorescent dye, IRDye 800CW, to detect HER2 overexpression in breast cancer cells. The stoichiometric ratios "n" and "m" refer to the number of diethylenetriaminepentaacetic acid dianhydride (DTPA) and IRDye 800CW molecules bound per trastuzumab molecule, respectively. METHODS: Fluorescence microscopy and confocal microscopy were used to determine the molecular specificity of (DTPA)(n)-trastuzumab-(IRDye800)(m) in vitro in SKBr3 (HER2-positive) and MDA-MB-231 (HER2-negative) breast cancer cells. SKBr3 cells were incubated with (DTPA)(n)-trastuzumab-(IRDye800)(m) or IRDye800CW or pretreated with trastuzumab or human IgG followed by (DTPA)(n)-trastuzumab-(IRDye800)(m) and examined under a fluorescence microscope. For in vivo characterization, athymic nude mice bearing HER2-overexpressing SKBr3-luc subcutaneous xenografts were injected intravenously with ((111)In-DTPA)(n)-trastuzumab-(IRDye800)(m) and imaged with SPECT and NIR fluorescence imaging at 48 h. Tumor-bearing mice were also injected intravenously with trastuzumab 24 h before administration of ((111)In-DTPA)(n)-trastuzumab-(IRDye800)(m). Nonspecific uptake in the SKBr3-luc tumors was analyzed by injecting the mice with IRDye 800CW and ((111)In-DTPA)(p)-IgG-(IRDye800)(q), where "p" and "q" are the stoichiometric ratios of DTPA and IRDye 800CW bound per IgG antibody, respectively. RESULTS: (DTPA)(n)-trastuzumab-(IRDye800)(m) showed significantly greater binding to SKBr3 cells than to MDA-MB-231 cells. Confocal imaging revealed that this binding occurred predominantly around the cell membrane. Competitive binding studies with excess trastuzumab before incubation with (DTPA)(n)-trastuzumab-(IRDye800)(m) abolished this binding affinity, but pretreatment with nonspecific IgG did not alter binding. In vivo nuclear and optical imaging of SKBr3-luc xenografts injected with ((111)In-DTPA)(n)-trastuzumab-(IRDye800)(m) revealed significantly more uptake in the tumor region than in the contralateral muscle region. The tumor-to-muscle ratio decreased in mice pretreated with trastuzumab and in mice injected with IRDye 800CW and ((111)In-DTPA)(p)-IgG-(IRDye800)(q). Ex vivo imaging of dissected organs confirmed these results. Finally, coregistration of histologic hematoxylin-eosin stains with autoradiography signals from tumor and muscle tissue slices indicated that ((111)In-DTPA)(n)-trastuzumab-(IRDye800)(m) bound only in tumor tissue and not to muscle. CONCLUSION: Dual-labeled ((111)In-DTPA)(n)-trastuzumab-(IRDye800)(m) may be an effective diagnostic biomarker capable of tracking HER2 overexpression in breast cancer patients.     

表皮生长因子受体2和血管内皮生长因子在胃癌中的表达及其临床意义

目的探讨胃癌中人表皮生长因子受体2(human epidermal growth factor receptor 2,HER2)和血管内皮生长因子(vascular endothelial growth factor,VEGF)的表达与胃癌的发生、发展的关系,及作为分子靶点指导胃癌患者临床用药的意义。方法采用免疫组化(immunohistochemistry,IHC)的方法检测103例胃癌患者HER2及VEGF的状态,同时联合荧光原位杂交的方法检测HER2的状态,并与患者的临床资料进行相关性分析。结果①胃癌中HER2扩增率约为11%(11/103),在阳性病例中IHC与荧光原位杂交(fluorescentin situ hydridization,FISH)方法的符合率为90%,具有相关性(P<0.01);②HER2的扩增与胃癌的病理分级、淋巴结转移与否及Lauren分型相关(P<0.05);③胃癌中VEGF表达阳性率约为24%(25/103),VEGF的阳性表达与肿瘤的浸润深度、病理分级、Lauren分型相关(P<0.05);④HER2的表达与VEGF的表达不相关(P>0.05)。结论 HER2、VEGF的阳性表达与胃癌特别是分化较好的胃管状腺癌的发生、发展密切相关。联合检测HER2及VEGF在胃癌(特别是肠型胃癌)中的表达对了解胃癌的发生、发展,及靶向药物曲妥珠单抗和贝伐单抗的选择具有重要意义。     

Mammographic features of calcifications in DCIS: correlation with oestrogen receptor and human epidermal growth factor receptor 2 status

Objective

This study investigated the correlation of oestrogen receptor (ER) and human epidermal growth factor receptor 2 (HER2) status with the probability of malignancy (POM) of mammographic calcifications in ductal carcinoma in situ (DCIS).

Methods

A total of 101 women (age range, 27–83 years) with pure DCIS that presented as mammographic calcifications were included. Three radiologists independently reviewed mammograms according to the BI-RADS lexicon and provided 100-point POM scores and a BI-RADS category. ER, HER2 and breast cancer subtypes were determined using immunohistochemistry (IHC) and fluorescence in situ hybridisation. Pairwise correlations between POM and IHC biomarker scores were calculated, and mammographic features were compared between breast cancer subtypes.

Results

HER2 level positively correlated with the POM score (P?<?0.0001) and BI-RADS category (P?<?0.0001), and ER level inversely correlated with the POM score (P?<?0.013) and BI-RADS category (P?<?0.010). Fine linear branching (P?=?0.004) and segmental (P?=?0.014) calcifications were significantly associated with HER2-positive cancers, and clustered calcifications were more frequently observed in ER-positive cancers (P?=?0.014).

Conclusion

HER2 status in DCIS correlated positively with the POM of mammographic calcifications, as determined by radiologists on the basis of the BI-RADS lexicon.

Key Points

? Prediction of malignancy on mammographic ductal carcinoma in situ is difficult. ? HER2 level correlated positively with the probability of malignancy assigned by radiologists. ? ER level correlated inversely with the probability of malignancy assigned by radiologists. ? HER2-positive DCIS more frequently exhibited fine linear branching or segmental calcifications. ? ER-positive DCIS more frequently exhibited clustered calcifications.     

Radiolabeled pertuzumab for imaging of human epidermal growth factor receptor 2 expression in ovarian cancer

Purpose

Human epidermal growth factor receptor 2 (HER2) is over-expressed in over 30% of ovarian cancer cases, playing an essential role in tumorigenesis and metastasis. Non-invasive imaging of HER2 is of great interest for physicians as a mean to better detect and monitor the progression of ovarian cancer. In this study, HER2 was assessed as a biomarker for ovarian cancer imaging using ⁶⁴Cu-labeled pertuzumab for immunoPET imaging.

Methods

HER2 expression and binding were examined in three ovarian cancer cell lines (SKOV3, OVCAR3, Caov3) using in vitro techniques, including western blot and saturation binding assays. PET imaging and biodistribution studies in subcutaneous models of ovarian cancer were performed for non-invasive in vivo evaluation of HER2 expression. Additionally, orthotopic models were employed to further validate the imaging capability of ⁶⁴Cu-NOTA-pertuzumab.

Results

HER2 expression was highest in SKOV3 cells, while OVCAR3 and Caov3 displayed lower HER2 expression. ⁶⁴Cu-NOTA-pertuzumab showed high specificity for HER2 (K_a?=?3.1?±?0.6 nM) in SKOV3. In subcutaneous tumors, PET imaging revealed tumor uptake of 41.8?±?3.8, 10.5?±?3.9, and 12.1?±?2.3%ID/g at 48 h post-injection for SKOV3, OVCAR3, and Caov3, respectively (n?=?3). In orthotopic models, PET imaging with ⁶⁴Cu-NOTA-pertuzumab allowed for rapid and clear delineation of both primary and small peritoneal metastases in HER2-expressing ovarian cancer.

Conclusions

⁶⁴Cu-NOTA-pertuzumab is an effective PET tracer for the non-invasive imaging of HER2 expression in vivo, rendering it a potential tracer for treatment monitoring and improved patient stratification.

     

乳腺癌人类表皮生长因子受体2表达与X线表现的相关性分析

目的对比分析人类表皮生长因子受体2(HER-2)阳性和阴性乳腺癌X线特征,探讨乳腺癌X线征象与HER-2基因之间的相关性。方法回顾性分析经手术病理确诊的812例女性乳腺癌患者的X线表现,根据免疫组织化学结果分为HER-2阳性组(235例)和HER-2阴性组(577例)。对比分析两组乳腺癌肿块和钙化的X线特征,肿块主要分析形态、边界及边缘,钙化主要分析形状及分布形式,并对各项分析结果进行检验,P<0.05为差异性有统计学意义。结果 HER-2阳性组乳腺癌较阴性组多表现为钙化(2=37.560,P=0.001),HER-2阴性组乳腺癌X线表现多为单纯肿块(2=37.560,P=0.001)。星芒状肿块在HER-2阴性组比例较高(2=5.912,P=0.015),两组类圆形(P=0.480)、分叶状(P=0.111)、不规则形肿块(P=0.150)分布比例则无明显统计学差异。HER-2阳性组乳腺癌肿块边界多模糊不清(2=8.319,P=0.004),阴性组肿块边界多为部分清楚(2=5.818,P=0.016)。HER-2阳性组乳腺癌钙化形态多表现为沙砾状(2=8.955,P=0.003)、多形性和不定形(2=7.137,P=0.008),分布形式无明显统计学差异。结论 HER-2阳性乳腺癌X线表现钙化居多,且多为沙砾状、多形性和不定形钙化,肿块边界多模糊不清;HER-2阴性乳腺癌多表现为单纯肿块,边界多为部分清楚,星芒状肿块多见。     

Preclinical pharmacokinetic, biodistribution, toxicology, and dosimetry studies of 111In-DTPA-human epidermal growth factor: an auger electron-emitting radiotherapeutic agent for epidermal growth factor receptor-positive breast cancer.

Our objective was to evaluate the pharmacokinetics, normal tissue distribution, radiation dosimetry, and toxicology of human epidermal growth factor (hEGF) labeled with (111)In ((111)In-diethylenetriaminepentaacetic acid [DTPA]-hEGF) in mice and rabbits. METHODS: (111)In-DTPA-hEGF (3.6 MBq; 1.3 or 13 microg) was administered intravenously to BALB/c mice. The blood concentration-time data were fitted to a 3-compartment model. Acute toxicity was studied with female BALB/c mice at 42 times the maximum planned human dose (MBq/kg) or with New Zealand White rabbits at 1 times the maximum planned human dose (MBq/kg) for a phase I clinical trial. Toxicity was evaluated by monitoring body weight, by determination of hematology and clinical biochemistry parameters, and by morphologic examination of tissues. Radiation dosimetry projections in humans were estimated on the basis of the residence times in mice by use of the OLINDA version 1.0 computer program. RESULTS: The largest amounts of radioactivity were taken up by the liver (41.3 +/- 7.8 [mean +/- SD] percentage injected dose [%ID] at 1 h after injection and decreasing to 4.9 +/- 0.3 %ID at 72 h after injection) and kidneys (18.6 +/- 0.8 %ID at 1 h and decreasing to 4.5 +/- 0.2 %ID at 72 h after injection). (111)In-DTPA-hEGF was cleared rapidly from the blood, with a half-life at alpha-phase of 2.7-6.2 min and a half-life at beta-phase of 24.0-36.3 min. The half-life of the long terminal phase could not be accurately determined. The volume of distribution of the central compartment was 340-375 mL/kg, and the volume of distribution at steady state was 430-685 mL/kg. There was no significant difference in the ratio of body weight at 15 d to pretreatment weight for mice administered (111)In-DTPA-hEGF (1.02 +/- 0.01) and mice administered unlabeled DTPA-hEGF (1.01 +/- 0.01). Erythrocyte, leukocyte, and platelet counts and serum alanine aminotransferase and creatinine levels remained in the normal ranges. No morphologic changes were observed by light microscopy in any of 19 tissues sampled. Minor morphologic changes in the liver were observed by electron microscopy. The projected whole-body dose in humans was 0.19 mSv.MBq(-1). The projected doses to the liver, kidneys, and lower large intestine were 0.76, 1.82, and 1.12 mSv.MBq(-1), respectively. CONCLUSION: (111)In-DTPA-hEGF was safely administered to mice and rabbits at multiples of the maximum dose planned for a phase I trial in breast cancer patients.     

Small-animal PET imaging of human epidermal growth factor receptor type 2 expression with site-specific 18F-labeled protein scaffold molecules.

Human epidermal growth factor receptor type 2 (HER2) is a well-established tumor biomarker that is overexpressed in a wide variety of cancers and that serves as a molecular target for therapeutic intervention. HER2 also serves as a prognostic indicator of patient survival and as a predictive marker of the response to antineoplastic therapy. The development of (18)F-labeled biomolecules for PET imaging of HER2 (HER2 PET) is very important because it may provide a powerful tool for the early detection of HER2-positive tumor recurrence and for the monitoring of HER2-based tumor treatment. METHODS: In this study, anti-HER2 monomeric and dimeric protein scaffold molecules [Z(HER2:477) and (Z(HER2:477))(2), respectively] were radiofluorinated at a reasonable radiochemical yield (13%-18%) by use of site-specific oxime chemistry. The resulting radiofluorinated protein scaffold molecules were then evaluated as potential molecular probes for small-animal HER2 PET by use of a SKOV3 tumor-bearing mouse model. RESULTS: The 4-(18)F-fluorobenzaldehyde conjugated aminooxy-protein scaffolds [(18)F-N-(4-fluorobenzylidene)oxime (FBO)-Z(HER2:477) and (18)F-FBO-(Z(HER2:477))(2)] both displayed specific HER2-binding ability in vitro. Biodistribution and small-animal PET imaging studies further revealed that (18)F-FBO-Z(HER2:477) showed rapid and high SKOV3 tumor accumulation and quick clearance from normal tissues, whereas (18)F-FBO-(Z(HER2:477))(2) showed poor in vivo performance (low tumor uptake and tumor-to-normal tissue ratios). The specificity of (18)F-FBO-Z(HER2:477) for SKOV3 tumors was confirmed by its lower uptake on pretreatment of tumor-bearing mice with the HER2-targeting agents Z(HER2) and trastuzumab. Moreover, small-animal PET imaging studies revealed that (18)F-FBO-Z(HER2:477) produced higher-quality tumor imaging than (18)F-FBO-(Z(HER2:477))(2). (18)F-FBO-Z(HER2:477) could clearly identify HER2-positive tumors with good contrast. CONCLUSION: Overall, these data demonstrate that (18)F-FBO-Z(HER2:477) is a promising PET probe for imaging HER2 expression in living mice. It has a high potential for translation to clinical applications. The radiofluorination method developed can also be used as a general strategy for the site-specific labeling of other proteins with (18)F. The protein scaffold molecules used here are attractive for the further development of PET probes for other molecular targets.     

Gefitinib对人结直肠癌细胞的生长抑制作用与表皮生长因子受体表达关系的研究

目的观察表皮生长因子受体(EGFR)酪氨酸激酶抑制剂Gefitinib对人结直肠癌细胞的生长抑制作用,探讨这种作用与结直肠癌细胞EGFR表达的关系。方法应用MTT法检测Gefitinib对6种结直肠癌细胞系的生长抑制效应,求出50%生长抑制剂量IC50;应用反转录半定量PCR(RT-PCR)检测不同结直肠癌细胞中EGFR的mRNA水平;应用Western blotting检测结直肠癌细胞中EGFR及其磷酸化蛋白(p-EGFR)的表达水平。结果Gefitinib在体外抑制结直肠癌细胞生长的IC50值为6.5~172.7μmol/L,以Lovo细胞最为敏感,HT29和SW480为中度敏感,HCT116、LS174和SW620表现为耐药。除SW620细胞以外,其他细胞系均不同程度地表达EGFR mRNA,以Lovo细胞表达最强,与其他细胞系比较差异有统计学意义(P<0.05);EGFR蛋白水平检测结果与mRNA相符,Lovo细胞的表达显著高于其他细胞系(P<0.05),HT29、SW480、HCT116和LS174T表达差异不明显,SW620几乎不表达;p-EGFR蛋白在Lovo细胞中的表达亦显著高于其他细胞系(P<0.05)。结论EGFR和p-EGFR的表达与Gefitinib对结直肠癌细胞的生长抑制作用可能存在相关性,EGFR和p-EGFR表达高则细胞对药物的敏感性好,但是EGFR不是决定结直肠癌细胞对Gefitinib敏感性的惟一因素。     

反义表皮生长因子受体对人肺癌细胞放射敏感性的影响

目的 观察反义表皮生长因子受体(EGFR)对人肺腺癌细胞系放射敏感性的影响。方法在脂质体介导下用质粒pcDNA3-反义EGFR(pcDNA3-antiEGFR)转染spc-a-1细胞,并以未转染(对照组)和空质粒pcDNA3转染(pcDNA3组)细胞作对照。用G418筛选稳定表达的细胞克隆,以RT-PCR和Western blot检测转染后EGFR的mRNA及蛋白表达抑制情况,流式细胞仪检测转染后细胞周期及单次照射8 Gy后各组细胞凋亡比例。3组细胞分别给予6 MV X射线照射0、2、4、6和8 Gy,计算克隆形成率,拟合生长曲线。结果pcDNA3-antiEGFR组与对照组、pcDNA3组比较,EGFR mRNA和蛋白表达量明显减少,G₂/M期比例分别为(29.53±1.91)％、(13.7±1.30)%和(12.40±1.34)％,单次照射8Gy后,3个组细胞的凋亡率分别为(39.24±1.57)%、(13.79±0.63)%和(15.02±0.85)%。与对照组相比较,pcDNA3-antiEGFR组细胞的D₀、D_q、SF₂值分别由2.11、2.49和0.84降至1.19、0.15和0.32,提示抑制EGFR表达,可降低spc-a-1细胞对射线所致亚致死性损伤的修复能力。结论反义EGFR可以降低人肺癌spc-a-1细胞中EGFR的表达,改变细胞周期分布,促进凋亡,降低亚致死性损伤的修复能力,增加肺癌细胞系spc-a-1的放射敏感性。     

ER阴性原发性乳腺癌HER-2过表达与X线表现及临床特征相关分析

目的：探讨雌激素受体阴性(ER-)乳腺癌患者中,人类表皮生长因子受体-2过表达(H ER-2+)与 X线及临床病理特征的关系。方法收集资料完整的ER-乳腺癌患者190例,其中 HER-2+患者78例,HER-2无过表达(HER-2-)患者112例,比较2组患者的 X线表现和临床病理特征。结果 HER-2+组与 HER-2-组比较,年龄分布具有显著性差异(P<0.001),HER-2+多见于高年龄患者(>60岁);HER-2+组更多伴有淋巴结转移(P=0.011)。X线表现方面,单纯钙化多见于 HER-2+组(P=0.000),单纯肿块多见于 HER-2-组(P<0.001)。HER-2+组多为分叶状肿块(P<0.001),毛刺多见(P=0.000),而 HER-2-组多为圆形肿块(P=0.014),边缘光滑(P=0.000)。钙化表现上,HER-2+组更多表现为恶性钙化(P=0.000)。结论 ER-乳腺癌 HER-2具有一定的临床及 X线特征,可以为临床医师在乳腺癌个体化诊疗中提供重要参考依据。     

抗角蛋白自身抗体对培养人舌鳞癌细胞表达表皮生长因子受体的免疫组化研究

 目的 探讨抗角蛋白自身抗体(AK auto Ab)对培养人舌鳞癌细胞表达表皮生长因子受体(FGFR)的作用.方法 用不同浓度AK aut Ab作用于培养人舌鳞癌细胞后,用免疫组化方法,测鳞癌细胞表达ECFR的变化,并做图像分析.结果 研究发现AK auto Ab对鳞癌细胞EGFR的表达有抑制作用,并呈浓度依赖性,经统计学检验显示有极显著意义(P<0.01).结论 AK auto Ab对鳞癌细胞EGFR的表达有抑制作用.