Expression of epidermal growth factor receptor and vascular endothelial growth factor in malignant canine epithelial nasal tumours*

Epidermal growth factor (EGF) and vascular endothelial growth factor (VEGF) signalling pathways play a role in carcinogenesis. Inhibition of EGF receptor (EGFR) and of VEGF is effective in increasing the radiation responsiveness of neoplastic cells both in vitro and in human trials. In this study, immunohistochemical evaluation was employed to determine and characterize the potential protein expression levels and patterns of EGFR and VEGF in a variety of canine malignant epithelial nasal tumours. Of 24 malignant canine nasal tumours, 13 (54.2%) were positive for EGFR staining and 22 (91.7%) were positive for VEGF staining. The intensity and percentage of immunohistochemically positive neoplastic cells for EGFR varied. These findings indicate that EGFR and VEGF proteins were present in some malignant epithelial nasal tumours in the dogs, and therefore, it may be beneficial to treat canine patients with tumours that overexpress EGFR and VEGF with specific inhibitors in conjunction with radiation.     

突变型猪表皮生长因子在毕赤酵母中的表达

使用α因子做为信号肽的酵母系统分泌表达猪表皮生长因子(pEGF)时,由于对信号肽末端Glu-Ala氨基酸残基切除不完全,表达产物是Glu-Ala-pEGF和pEGF的混合物.本研究为了获得单一表达的pEGF产物,对pEGF基因进行适当的突变修改,构建缺失Glu-Ala重复基因序列的重组载体.把重组载体pPIC9-pEGF1-48电转化毕赤酵母,用同位素标记随机引物斑点杂交法筛选多拷贝整合转化子,并诱导大量表达.用硫酸铵沉淀及超滤的方法浓缩和纯化蛋白,并用Bradford检测方法对蛋白浓度进行了初步测定.结果表明,构建的重组载体经过BglⅡ线性化后稳定转入毕赤酵母中,转化子表型主要为MutS型;选的多拷贝MutS型转化子经诱导后成功表达约6 000的pEGF1-48蛋白,经检测蛋白表达水平约为34 mg/L.     

Expression of vascular endothelial growth factor in canine mammary tumors

Vascular endothelial growth factor (VEGF) is a dimeric protein that stimulates angiogenesis in vitro and in vivo by inducing endothelial cell proliferation and migration. In this immunohistochemical study, VEGF-immunolabeled cells were counted in a series of 10 benign and 40 malignant canine mammary tumors. The morphologic pattern of VEGF positivity (intensity of immunolabeling and VEGF granule size and distribution) was also evaluated. A low number of cells weakly positive for VEGF with few and small granules polarized to the luminal pole was detected in benign neoplasms. In contrast, in malignancies a high number of VEGF-positive cells had strong immunolabeling, often with large granules found diffusely in the cytoplasm. This level of immunolabeling was more pronounced in the less differentiated, more malignant phenotypes (grade 3). Macrophages, which can synthesize VEGF, were strongly positive. Stromal and myoepithelial cells were negative. VEGF data were correlated statistically with intratumoral microvessel density (number of newly formed microvessels) and both measures were greater in less differentiated malignant neoplasms, demonstrating that angiogenesis and malignancy increase together. VEGF appears to be a powerful angiogenic factor in canine mammary tumors.     

Expression of vascular endothelial growth factor in N-butyl-N-(4-hydroxybutyl)nitrosamine-induced rat bladder carcinogenesis

Vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) are proteins implicated in tumor-associated microvascular angiogenesis. Expressions of VEGF and bFGF in various stages of chemical-induced rat bladder carcinogenesis were immunohistochemically investigated. Thirty-two male 6-week-old Wistar rats were given drinking water containing 0.05% N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) for 20 weeks. VEGF and bFGF were not detected in the normal bladder epithelium. In simple hyperplasia, intensive expression of VEGF was observed in a few epithelial cells, and the expression of epithelial VEGF became more pronounced in papillary or nodular (PN) hyperplasia and papilloma. In carcinoma, heterogeneous expression of VEGF was observed in focal tumor cells, intensely expressed in the invading tumor cells. Ultrastructurally, carcinoma cells showed VEGF immunoreactivity in the cytoplasmic matrix and some rough endoplasmic reticulum, and VEGF-positive and -negative carcinoma cells were also clearly defined. High levels of VEGF mRNA were observed in the carcinoma. However, bFGF was not detected in the epithelium throughout the carcinogenesis. Increased microvessel counts appeared at simple hyperplasia and became more pronounced in PN hyperplasia, papilloma, and carcinoma (F-test; P < 0.05). In the carcinoma, the microvessel counts of the VEGF-expressing tumor areas were significantly higher than that of the non-VEGF-expressing tumor areas (U-test; P < 0.05). The present study suggests that upregulation of epithelial VEGF may begin at a quite early stage in BBN-induced rat bladder carcinogenesis, but bFGF may not be involved.     

The localization and expression of epidermal growth factor and epidermal growth factor receptor in bovine ovary during oestrous cycle

Epidermal growth factor (EGF) is one of the important regulatory factors of EGF family. EGF has been indicated to effectively inhibit the apoptosis of follicular cells, to promote the proliferation of granulosa cells and the maturation of oocytes, and to induce ovulation process via binding to epidermal growth factor receptor (EGFR). However, little is known about the distribution and expression of EGF and EGFR in cattle ovary especially during oestrous cycle. In this study, the localization and expression rule of EGF and EGFR in cattle ovaries of follicular phase and luteal phase at different time points in oestrous cycle were investigated by using IHC and real-time qPCR. The results showed that EGF and EGFR in cattle ovary were mainly expressed in granulosa cells, cumulus cells, oocytes, zona pellucida, follicular fluid and theca folliculi externa of follicles. The protein and mRNA expression of EGF/EGFR in follicles changed regularly with the follicular growth wave both in follicular and in luteal phase ovaries. In follicular phase ovaries, the protein expression of EGF and EGFR was higher in antral follicles than that of those in other follicles during follicular growth stage, and the mRNA expression of EGFR was also increased in stage of dominant follicle selection. However, in luteal phase ovaries, the growth of follicles was impeded during corpus luteum development under the action of progesterone secreted by granular lutein cell. The mRNA and protein expressions of EGF and EGFR in ovarian follicles during oestrous cycle indicate that they play a role in promoting follicular development in follicular growth waves and mediating the selection process of dominant follicles.     

Expression of transforming growth factor beta(1), beta(3), and basic fibroblast growth factor in full-thickness skin wounds of equine limbs and thorax

OBJECTIVE--To map the expression of transforming growth factor (TGF)-beta(1), TGF-beta(3), and basic fibroblast growth factor (bFGF) in full-thickness skin wounds of the horse. To determine whether their expression differs between limbs and thorax, to understand the pathogenesis of exuberant granulation tissue. STUDY DESIGN--Six wounds were created on one lateral metacarpal area and one midthoracic area of each horse. Sequential wound biopsies allowed comparison of the temporal expression of growth factors between limb and thoracic wounds. ANIMALS--Four 2- to 4-year-old horses. METHODS--Wounds were assessed grossly and histologically at 12 and 24 hours, and 2, 5, 10, and 14 days postoperatively. ELISAs were used to measure the growth factor concentrations of homogenates of wound biopsies taken at the same timepoints. RESULTS--TGF-beta(1) peaked at 24 hours in both locations and returned to baseline in thoracic wounds by 14 days but remained elevated in limb wounds for the duration of the study. Expression kinetics of TGF-beta(3) differed from those of TGF-beta(1). TGF-beta(3) concentrations gradually increased over time, showing a trend toward an earlier and higher peak in thoracic compared with limb wounds. bFGF expression kinetics resembled those of TGF-beta(1), but no statistically significant differences existed between limb and thoracic wounds. CONCLUSIONS--Growth factor expression is up-regulated during normal equine wound repair. TGF-beta(1) and TGF-beta(3) show a reciprocal temporal regulation. Statistically significant differences exist between limb and thoracic wounds with respect to TGF-beta(1) expression. CLINICAL RELEVANCE--The persistence of TGF-beta(1) expression in leg wounds may be related to the development of exuberant granulation tissue in this location, because TGF-beta(1) is profibrotic.     

Expression of vascular endothelial growth factor in canine oral malignant melanoma

Serum, plasma and tissue expression of vascular endothelial growth factor (VEGF) was measured in 20 dogs previously diagnosed histologically with oral melanoma. The concentrations of VEGF in serum and plasma were significantly higher in dogs with melanoma than in a control population (P ≤ 0.002). Concentrations of VEGF in the serum and plasma of dogs with melanoma were highly correlated (r = 0.867). Ninety‐five per cent of melanoma tissues expressed VEGF. Two staining patterns were detected: diffuse and granular cytoplasmic staining. High blood concentrations of VEGF were correlated to a shorter survival time in dogs receiving definitive therapy (P = 0.002). Survival times were significantly longer in dogs receiving definitive therapy versus palliative therapy (median 496 versus 97 days, P = 0.007). Blood concentrations of VEGF were associated with stage (P < 0.05). Dogs with oral melanoma have increased serum, plasma and tissue concentrations of VEGF. Increased expression of VEGF may be a reasonable target for future therapy of canine oral melanoma.     

Expression of epidermal growth factor receptor (EGFR) and Ki67 in feline oral squamous cell carcinomas (FOSCC)

The aims of this study were to establish expression of epidermal growth factor receptor (EGFR) and Ki67 in 67 archived biopsy samples of feline oral squamous cell carcinomas (FOSCCs) and to establish if the expression of either markers was predictive of survival. Samples were immunohistochemically labelled for the two proteins and scored. Statistical analyses of data, including Kaplan-Meier survival curves, were performed. All samples expressed both markers although levels differed between samples. Median overall survival was 46 days and 1-year survival was 5%. There was no correlation between Ki67 and EGFR scores (Pearson's correlation coefficient, P = 0.861). Low cellular proliferation (low Ki67 score) was positively correlated with an overall longer survival (Log Rank, P = 0.02) and a trend towards better survival for the high EGFR group was observed (Log Rank, P = 0.076). Ki67 and EGFR immunostaining in FOSCC may be of value as biochemical markers for screening of biopsies from cases of FOSCC.     

趾叶炎小鼠血管内皮生长因子表达的研究

采用组织化学和免疫组化的染色方法,检测趾叶炎趾部组织中血管内皮生长因子表达水平、炎性细胞、肥大细胞及其脱颗粒的动态变化,探讨血管内皮生长因子(VEGF)在趾叶炎发病中的作用。结果表明,二磷酸组织胺注射后炎症组小鼠趾部血管内皮生长因子在真皮网状层、血管及腺体周围和部分肥大细胞内,在14 h表达达到一个峰值,而后表达减弱,72 h~15 d表达迅速增强;炎症组小鼠趾部肥大细胞及其脱颗粒和炎性细胞数量,随二磷酸组织胺注射时间的延长,急剧增多,均极显著高于正常组(P(0.01),且其变化趋势均与血管内皮生长因子表达趋势相吻合;同时在真皮出现了许多增生的小动脉,管壁增厚,管腔内有血栓形成。结果说明血管内皮生长因子参与小鼠趾叶炎的发病过程。     

Expression of vascular endothelial growth factor (VEGF) associated with histopathological changes in rodent models of osteoarthritis

Vascular endothelial growth factor (VEGF) and its receptors have recently reported to be expressed in human osteoarthritis (OA), suggesting that VEGF could be implicated in the pathogenesis of this disease. In the present study, expression of VEGF in the articular cartilage was determined in three different OA models: medial meniscectomy and monoiodoacetate (MIA) injection in rats and age-associated spontaneous joint cartilage destruction in guinea pigs. VEGF was detected by immunohistochemical analysis in the regenerative and hypertrophic chondrocytes, perichondrium and osteophyte areas and chondrocyte clones. Stain intensity of VEGF immunoreactivity increased simultaneously with the degree of cartilage destruction and reparation. These results suggest that VEGF is a key factor in the articular cartilage in human OA and animal OA models.     

Immunohistochemical expression of vascular endothelial growth factor and vascular endothelial growth factor receptor associated with tumor cell proliferation in canine cutaneous squamous cell carcinomas and trichoepitheliomas

The expression of 5 markers associated with angiogenesis was studied in canine squamous cell carcinomas (SCCs) (n = 19) and canine trichoepitheliomas (TCPs) (n = 24). SCCs were assigned histologic grades, and tissue sections from both tumor types were immunohistochemially stained for the expression of vascular endothelial growth factor (VEGF), vascular endothelial growth factor receptor-2 (VEGFR-2), as well as intratumoral microvessel density (iMVD), tumor proliferation index (PI), and tumor apoptotic index (AI), using antibodies against VEGF, VEGFR-2, von Willebrand's factor, Ki-67 antigen, and the terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate end-labeling method (TUNEL), respectively. VEGF and VEGFR-2 were detected in 17/19 (89.4%) and 19/19 (100%) SCCs and in 17/24 (70.8%) and 20/24 (83.3%) TCPs, respectively. In SCCs, there was substantial correlation between histologic grade and PI (r = 0.51); and moderate correlation between VEGF and histologic grade (r = 0.43), VEGFR-2 and histologic grade (r = 0.47), VEGF and PI (r = 0.47), and VEGFR-2 and PI (r = 0.47) (Spearman rank correlation coefficient). In TCPs, there was substantial correlation between VEGF and PI (r = 0.51) and a moderate correlation between VEGFR-2 and iMVD (r = 0.36). The median iMVD of SCCs (15.5) was significantly higher than the median iMVD of TCPs (9.05) (P value < .05). It was concluded that VEGF and VEGFR-2 may promote tumor cell proliferation in TCPs and SCCs. An autocrine pathway for VEGF probably operates in canine SCCs and TCPs, as VEGF and VEGFR-2 expression was found in most tumors and was associated with evidence for tumor cell proliferation.     

Advances in studies on vascular endothelial growth factor receptor and its small-molecule inhibitors

目前抗血管生成治疗是抗肿瘤研究的热点.血管内皮生长因子(VEGF)是刺激血管生成的重要因子之一,血管内皮生长因子受体(VEGFR)在肿瘤新生血管中高表达,因此成为肿瘤靶向治疗的理想靶点.以VEGF、VEGFR为靶点的抗肿瘤药物除了常见的单克隆抗体药物阿伐斯汀外,小分子抑制剂舒尼替尼、索拉非尼等也已经广泛使用;另外,一些具有上市潜力的药物,如范得他尼、西地尼布、瓦他拉尼、阿西替尼等也值得关注.已上市和正在进行临床研究的VEGFR小分子抑制剂按结构大致分为6类:喹啉及喹唑啉类、哒嗪类、吲唑类、咪唑和吡咯嘧啶类、吲哚类和其他结构等.对VEGF、VEGFR的生物学功能,其代表性的小分子抑制剂研究进行综述.     

Immunolocalization of epidermal growth factor (EGF) and EGF receptors in the porcine upper gastrointestinal tract.

The factors controlling growth and maturation in the porcine gastrointestinal tract are not well understood. Epidermal growth factor (EGF) is a polypeptide that has been implicated in the control of gastrointestinal tract growth, maturation, and protection in other species. Immunoreactive EGF (IR-EGF) and EGF receptors (EGF-R) were histochemically identified in formalin-fixed tissues of the upper digestive tract of 1-, 3-, 7-, 14-, 21-, and 28-day-old pigs. The ductal epithelium consistently contained IR-EGF in the parotid salivary gland of pigs of all ages and in the mandibular salivary gland in pigs greater than or equal to 7 days old. Immunoreactive EGF was detected in the mucosal epithelium of the esophagus and nonglandular portion of the stomach, and in the pancreas and liver in all pigs. Gastric gland IR-EGF was inconsistently detected in pigs less than 14 days old and was consistently observed in all older pigs. Enterocyte EGF immunoreactivity was usually weak and was variably detected in the duodenum of pigs less than or equal to 7 days old and in the jejunum of pigs less than or equal to 14 days old, but was consistently observed in older pigs. Ileal immunoreactivity was erratic. Immunoreactive EGF-R were identified in the esophageal epithelium of all pigs, and in the nonglandular gastric and glandular gastric mucosa of all pigs, except for two 7-day-old pigs and one 7-day-old pig, respectively. Immunoreactive EGF-R were detected in the duodenal, jejunal, and ileal enterocytes of pigs of all ages examined.     

Epidermal growth factor and epidermal growth factor receptor immunoreactivity in the endothelial cells of the uterine artery and its branches during different stages of the estrous cycle in the pig

The uterine artery and its branches are the most important vessels that supply the uterus with blood, nutrients and active substances. Epidermal growth factor (EGF) and its receptor (EGFR) are expressed in many tissues, including reproductive organs, and is involved in angiogenesis, embryo implantation and development as well as in proliferation and differentiation of various cells. The aim of our study was to determine EGF and EGFR immunoexpression in the uterine artery and its branches during the estrous cycle in the pig. The experiment was performed on cryostat sections of the uterine artery and its branches stained immunohistochemically by ABC method. Light microscopic observations revealed the phase-related immunoreactivity of EGF and EGFR in the endothelial cells of the uterine artery and its branches. The highest intensity of EGF and EGFR immunoreaction in endothelial cells of the uterine artery was observed in the follicular phase. A significant decrease in the intensity of EGF and EGFR immunoreactivity was found in the middle luteal phase. Similar results of the immunostaining were found with regard to EGFR. In the endothelium of the uterine arterial branches, a significant increase in the intensity of EGF and EGFR-immunoreactivity was observed in the middle luteal phase. A decrease in the intensity of EGF immunostaining was observed in the late luteal phase. The phase-related expression of EGF and EGFR in the endothelium of the uterine artery and its branches suggest the modulatory effect of EGF and its receptor on the uterine artery and the region supplying these vessels.     

Localization of fibroblast growth factor I (acid fibroblast growth factor) and its mRNA in the bovine mammary gland during mammogenesis, lactation and involution

Growth factors are involved in development and function of the mammary gland. The aim of this study was the localization of fibroblast growth factor 1 (FGF-1) and its mRNA in the bovine mammary gland during different developmental and functional stages. Mammary tissue was obtained from German Brown Swiss cows (n = 23) during defined stages of mammogenesis (before and during pregnancy), lactogenesis, peak lactation and involution. The distribution of FGF-1 mRNA was studied using non-radioactive in situ hybridization, the corresponding FGF-protein was analysed using immunohistochemistry [avidin-biotin peroxidase complex (ABC)-method]. A moderate to distinct staining for FGF-mRNA was found in the epithelium of ducts and developing alveoli during mammogenesis. Post-partum at the same cellular locations, a considerable amount of FGF-1 mRNA, was seen that decreased during lactation. Also during early involution clear staining for FGF-mRNA could still be observed. Immunoreactive FGF-1 was found in considerable concentration in the epithelium of the mammary gland in heifers. The staining intensity generally decreased somewhat during mammogenesis and lactation, but could be always clearly demonstrated in the secretory epithelial cells of alveoli and glandular ducts. Also during the first day after the end of milking, the epithelium displayed a moderate to distinct epithelial immunostaining. Notably, After 4 weeks of involution, in many alveoli a shedding of the FGF-1 positive luminal cell layer was found. In our localization studies, no strict correlation between FGF-1 mRNA and its corresponding protein was found. The various reasons for this finding are discussed.