Isolation and characterization of anti c-met single chain fragment variable (scFv) antibodies

The receptor tyrosine kinase (RTK) Met is the cell surface receptor for hepatocyte growth factor (HGF) involved in invasive growth programs during embryogenesis and tumorgenesis. There is compelling evidence suggesting important roles for c-Met in colorectal cancer proliferation, migration, invasion, angiogenesis, and survival. Hence, a molecular inhibitor of an extracellular domain of c-Met receptor that blocks c-Met-cell surface interactions could be of great thera-peutic importance. In an attempt to develop molecular inhibitors of c-Met, single chain variable fragment (scFv) phage display libraries Tomlinson I?+?J against a specific synthetic oligopeptide from the extracellular domain of c-Met receptor were screened; selected scFv were then characterized using various immune techniques. Three c-Met specific scFv (ES1, ES2, and ES3) were selected following five rounds of panning procedures. The scFv showed specific binding to c-Met receptor, and significantly inhibited proliferation responses of a human colorectal carcinoma cell line (HCT-116). Moreover, anti- apoptotic effects of selected scFv antibodies on the HCT-116 cell line were also evaluated using Annexin V/PI assays. The results demonstrated rates of apoptotic cell death of 46.0, 25.5, and 37.8% among these cells were induced by use of ES1, ES2, and ES3, respectively. The results demonstrated ability to successfully isolate/char-acterize specific c-Met scFv that could ultimately have a great therapeutic potential in immuno-therapies against (colorectal) cancers.     

C-Met在ICR小鼠下颌第一磨牙牙胚中的表达

目的探讨c-Met在小鼠下颌第一磨牙牙胚发育中的表达情况。方法采用孕12d、13d、14d、16d、18d ICR胎鼠及出生后2d ICR仔鼠的头部制作冰冻切片,以抗小鼠c-Met多克隆抗体对冰冻切片进行免疫荧光实验,激光共聚焦显微镜观察。结果 c-Met在牙胚蕾状期、帽状期的上皮、钟状期的内釉上皮、成釉细胞和成牙本质细胞中有表达;牙胚和口腔黏膜连接区域两侧的间充质中、牙乳头及蕾状早期颊侧下方下颌的间充质中c-Met也有表达。结论 C-Met对于牙齿的形态发生,成釉细胞和成牙本质细胞的分化,牙乳头细胞的发育可能具有重要作用。     

HGF/c-Met、VEGF和uPA在口腔鳞癌组织中的表达及意义

目的：探讨口腔鳞癌中HGF/c-Met、VEGF和uPA的表达及其相关性。方法：应用免疫组织化学SP法检测63例口腔癌、20例正常口腔黏膜的HGF/c-Met、VEGF和uPA蛋白表达。结果：①HGF/c-Met、VEGF和uPA阳性表达率：口腔鳞癌中分别为98.41%、100%、92.06%、88.89%,均显著高于正常口腔黏膜中表达率（5.00%、10.00%、20.00%、15.00%）,P〈0.05;有淋巴结转移的口腔癌组强阳性表达率分别为72.73%、77.27%、72.73%、68.82%,高于无转移组（53.66%、46.34%、46.34%、43.90%）。T3、T4期HGF/c-Met、VEGF和uPA的强阳性表达（93.10%、82.76%、72.41%、79.31%）高于T1、T2期（32.35%、35.29%、41.18%、29.41%）,P〈0.05。②口腔鳞癌中HGF/c-Met、VEGF和uPA表达呈正相关。结论：HGF/c-Met、VEGF和uPA表达与口腔癌的发生、发展相关,对口腔鳞癌的浸润、转移起促进作用且相互协同,是口腔鳞癌侵袭的重要标志物。     

c-Met siRNA对肝细胞生长因子诱导的人胆管癌QBC939细胞增殖的影响

目的:近年来胆管癌的发病率和病死率呈上升的趋势,5年生存期低于5%,因此亟需利用现代生物技术探索新的治疗方法.探讨针对肝细胞生长因子(HGF)受体c-Met的RNA干扰对人胆管癌(CCA)QBC939细胞增殖的影响. 方法:构建针对人c-Met基因的小干扰RNA(siRNA),转染体外培养的人CCA QBC939细胞,应用MTT法检测细胞增殖,Western blot检测c-Met、细胞周期素(Cyclin)D1和A表达以及磷酸肌醇-3激酶/蛋白激酶B(P13K/Akt)和胞外信号调节激酶(ERK1/2)信号通路活化. 结果:c-Met siRNA显著抑制c-Met蛋白表达,且随着其浓度的增加,c-Met蛋白表达逐渐下降,500nmol/L c-Met siRNA对c-Met蛋白表达的抑制率达65%.HGF刺激24 h,细胞增殖是对照组的4.54倍,100nmol/L c-Met siRNA预处理即显著抑制HGF诱导的细胞增殖,其抑制率达26%,且随浓度增加,其抑制作用逐渐增强,500nmol/L c-Met siRNA对HGF诱导的细胞增殖的抑制率达85%.HGF刺激4h,PI3K和Akt的活性即显著增强,分别是对照组的4.09和4.54倍,c-Met siRNA可呈浓度依赖性的抑制HGF诱导的P13K/Akt活化,500 nmol/L c-Met siRNA几乎完全抑制HGF诱导的PI3K/Akt活化.HGF显著诱导人CCAQBC939细胞ERK1/2活化,50ng/ml HGF刺激4 h,磷酸化ERK1/2表达是对照组的3.63倍,c-Met siRNA可呈浓度依赖性的抑制HGF诱导的ERK1/2活化.HGF显著诱导人CCA QBC939细胞细胞周期素D1和A表达,分别是对照组的2.83和3.16倍,c-Met siRNA可呈浓度依赖性的抑制HGF诱导的细胞周期素D1和A表达. 结论:针对人c-Met基因的RNA干扰可有效阻断人CCA QBC939细胞c-Met表达,并通过阻断P13K/Akt和ERK1/2信号通路活化而抑制HGF诱导的细胞增殖.     

Renal expression of alpha-smooth muscle actin and c-Met in children with Henoch–Schönlein purpura nephritis

Alpha-smooth muscle actin (α-SMA) is the actin isoform that predominates within vascular smooth-muscle cells and plays an important role in fibrogenesis. On the other hand, c-Met is the receptor for hepatocyte growth factor (HGF), which plays a role in protection from injury and has anti-fibrogenetic effects. To clarify whether α-SMA and HGF are associated with the progression of renal injury in Henoch–Schönlein purpura nephritis (HSPN), we evaluated the renal expression of α-SMA and c-Met in HSPN patients. Patients were divided into three groups. Group 1 consisted of eight patients (male:female 4:4) with stage II or less in the classification of the International Study of Kidney Disease in Children (ISKDC), Group 2 consisted of 20 patients (male:female 11:9) with ISKDC stage III or greater and a good prognosis, and group 3 consisted of seven patients (male:female 3:4) with ISKDC stage III or greater and poor prognosis. Renal biopsy findings, including c-Met and α-SMA staining, were investigated for each group. At first biopsy, the mean scores for renal α-SMA and glomerular c-Met in groups 2 and 3 were higher than those in group 1, while mean scores for neither renal α-SMA nor glomerular c-Met differed between groups 2 and 3. At second biopsy, the mean scores for renal α-SMA staining in group 3 were higher than those in group 2, and mean score for glomerular c-Met staining in group 3 was lower than that in group 2. In groups 2 and 3, the mean scores for glomerular and interstitial α-SMA staining at first biopsy were correlated with the chronicity index (CI) at second biopsy, but the mean score for glomerular c-Met staining at first biopsy correlated with neither the activity index (AI) nor CI in the first or second biopsies in all groups. Our findings suggest that the expression of renal α-SMA may be associated with progression of renal injury in HSPN.     

Disease-dependent reciprocal phosphorylation of serine and tyrosine residues of c-Met/HGF receptor contributes disease retardation of a transgenic mouse model of ALS

Amyotrophic lateral sclerosis (ALS) is a fatal disease characterized by progressive degeneration of motoneurons. We have demonstrated that hepatocyte growth factor (HGF) attenuates loss of both spinal and brainstem motoneurons of ALS model mice expressing mutated human SOD1^G93A (G93A). This study was designed to assess disease-dependent regulatory mechanisms of c-Met/HGF receptor (c-Met) activation in the facial motoneurons of G93A mice. Using double transgenic mice expressing HGF and mutated SOD1^G93A (G93A/HGF), we showed that phosphorylation of c-Met tyrosine residues at positions 1230, 1234 and 1235 (phospho-Tyr), and thereby its activation, was slightly evident in G93A and highly obvious in G93A/HGF mice (but absent in WT and HGF-Tg mice). Phosphorylation of the c-Met serine residue at position 985 (phospho-Ser), a residue involved in the negative regulation of its activation, was evident in WT and HGF-Tg mice. Protein phosphatase 2A (PP2A), which is capable of dephosphorylating c-Met phospho-serine, is upregulated in the facial motoneurons of G93A and G93A/HGF mice compared with WT and HGF-Tg mice. Thus, c-Met activation is reciprocally regulated by phosphorylation between c-Met serine and tyrosine residues through PP2A induction in the presence or absence of mutant SOD1 expression, and HGF functions more efficiently in ALS and ALS-related diseases.     

Development of speech and hearing of two children with Pelizaeus-Merzbacher disease presenting only waves I and II of the auditory brainstem response

Pelizaeus-Merzbacher disease (PMD) is a white matter dystrophy of the brain. Most children with PMD require comprehensive nursing care. Their speech and language abilities are poor or absent. Therefore, evaluating hearing ability is difficult in children with PMD. We have followed up two patients with PMD since early childhood. Patient 1 is an 11-year-old boy, and patient 2 is a 15-year-old adolescent boy in whom horizontal nystagmus was recognized after birth. Magnetic resonance imaging showed diffuse dysmyelination of the cerebral white matter. Auditory brainstem response recordings showed only waves I and II and the absence of all subsequent components. However, conditioned orientation reflex audiometry showed a threshold of 20-30 dB. Both patients can converse orally and have auditory perception and speech abilities better than those of most patients with PMD in the literature. We report on the development of their hearing and speech abilities.     

The tumour-stromal interaction between intratumoral c-Met and stromal hepatocyte growth factor associated with tumour growth and prognosis in non-small-cell lung cancer patients

Immunohistochemical analyses of the effects of hepatocyte growth factor (HGF) and c-Met expression on tumour growth and angiogenesis were performed on 88 patients with non-small-cell lung cancers (NSCLCs). In all, 22 carcinomas (25.0%) were intratumoral HGF-positive, 14 carcinomas (15.9%) were stromal HGF-positive, and 36 carcinomas (40.9%) were intratumoral c-Met-positive. None of the carcinomas were stromal c-Met-positive. Examination of tumour growth revealed that the frequency of tumours with a high Ki-67 index was significantly greater for stromal HGF-positive tumours than for stromal HGF-negative tumours (P=0.0197). The frequency of tumours with a high Ki-67 index was also significantly greater for intratumoral c-Met-positive tumours than for intratumoral c-Met-negative tumours (P=0.0301). However, there was no significant difference in tumour vascularity with relation to intratumoral HGF status, stromal HGF status, and intratumoral c-Met status. The survival rate of patients with intratumoral c-Met-positive tumours was significantly lower than for patients with c-Met-negative tumours (P=0.0095). Furthermore, the survival rate of patients with both intratumoral c-Met-positive and stromal HGF-positive tumours was significantly lower than for patients with either positive tumours, and that of patients with both negative tumours (P=0.0183 and P=0.0011, respectively). A univariate analysis revealed that intratumoral c-Met expression was a significant prognostic factor of NSCLC patients (relative risk=2.642, P=0.0029). The present study demonstrates that tumour-stromal interaction between tumour cell-derived c-Met and stromal cell-derived HGF affects tumour growth and the prognosis of NSCLC patients.