Bacterial expression of 183-227aa region of HER3 extracellular domain I and preparation and identification of its polyclonal antibodies / 南方医科大学学报

OBJECTIVE@#To prepare the recombinant peptide MVF-HER3 I composed of the 183-227aa peptide segment of human epidermal growth factor receptor 3 (HER3 I) and the measles virus protein 288-302 peptide segment (MVF), and prepare polyclonal antibodies (PcAb) against this recombinant peptide.@*METHODS@#The MVF-HER3 I gene was synthesized chemically and subcloned into pET21b or pET32a plasmid containing Thioredoxin (Trx) tag gene. The recombinant plasmids were identified by endonuclease digestion. MVF-HER3 I was expressed in BL21(DE3) cells under an optimal bacterial expression condition. The fusion protein Trx-MVF-HER3 I was purified using nickel ion affinity chromatography, and the purified protein was digested by enterokinase to remove Trx tag. The digested mixture underwent further nickel ion affinity chromatography to obtain purified MVF-HER3 I. The purified MVF-HER3 I was used to immunize SD rats subcutaneously for preparing anti-MVF-HER3 I PcAb. The titer of PcAb was determined using ELISA. The bindings of anti-MVF-HER3 I PcAb to MVF-HER3 I, native HER3 and MCF7 cells were analyzed using immunoblotting, immunoprecipitation and laser confocal microscopy. The growth inhibition effect of the antibodies on MCF7 cells cultured in the absence or presence of NRG was assessed using sulforhodamine B.@*RESULTS@#The recombinant peptide gene could not be expressed alone, but could be efficiently expressed after fusion with Trx gene under optimized conditions. The fusion peptide MVF-HER3 I was successfully prepared from Trx-MVF-HER3 I. The anti-MVF-HER3 I PcAb, with a titer reaching 1: 512 000, specifically bound to MVF-HER3 I, recognized native HER3 and bound to the membrane of MCF7 cells. The obtained PcAb could dose-dependently inhibit the growth of MCF7 cells irrespective of the presence or absence of NRG.@*CONCLUSIONS@#We successfully obtained the recombinant peptide MVF-HER3 I and prepared its PcAb, which can facilitate further functional analysis of HER3 signaling pathway.

ErbB1 and ErbB3 co-over expression as a prognostic factor in gastric cancer

BACKGROUND: Epidermal growth factor receptor family members such as ErbB1 and ErbB3 are involved in tumor progression and metastasis. Although, there are various reports about the prognostic value of EGFR members separately in gastric cancer, there is not any report about the probable correlation between ErbB1 and ErbB3 co-expression and gastric cancer prognosis. In present study, we assessed the correlation between ErbB1 and ErbB3 co-overexpression (in the level of mRNA and protein expression) and gastric cancer prognosis for the first time. METHODS: ErbB1 and ErbB3 expressions were analyzed by immunohistochemistry and real-time PCR in 50 patients with gastric cancer. Parametric correlations were done between the ErbB1 and ErbB3 expression and clinicopathological features. Multivariate and logistic regression analyses were also done to assess the roles of ErbB1 and ErbB3 in tumor prognosis and survival. RESULTS: There were significant correlations between ErbB1/ErbB3 co-overexpression and tumor size (p = 0.026), macroscopic features (p < 0.05), tumor differentiation (p < 0.05), stage of tumor (p < 0.05), and recurrence (p < 0.05). Moreover, ErbB1/ErbB3 co-overexpression may predict the survival status of patients (p < 0.05). CONCLUSION: ErbB1 and ErbB3 co-overexpression is accompanied with the poor prognosis and can be used efficiently in targeted therapy of gastric cancer patients.

Expressions of miR-22 and miR-135a in acute pancreatitis / 华中科技大学学报（医学）（英德文版）

This study examined the expressions of miR-22 and miR-135a in rats with acute edematous pancreatitis (AEP) and their target genes in order to shed light on the involvement of miR-22 and miR-135a in the pathogenesis of acute pancreatitis (AP). The in vivo model of AEP was established by introperitoneal injection of L-arginine (150 mg/kg) in rats. The miRNA microarray analysis was used to detect the differential expression of miRNAs in pancreatic tissue in AEP and normal rats. The in vitro AEP model was established by inducing the rat pancreatic acinar cell line (AR42J) with 50 ng/mL recombinant rat TNF-α. Real-time quantitative RT-PCR was employed to detect the expression of miR-22 and miR-135a in AR42J cells. Lentiviruses carrying the miRNA mimic and anti-miRNA oligonucleotide (AMO) of miR-22 and miR-135a were transfected into the AR42J cells. The AR42J cells transfected with vehicle served as control. Western blotting was used to measure the expression of activated caspase3 and flow cytometry analysis to detect the apoptosis of AR42J cells. Targets of miR-22 and miR-135a were predicted by using TargetScan, miRanda, and TarBase. Luciferase reporter assay and quantitative real-time RT-PCR were performed to confirm whether ErbB3 and Ptk2 were the target gene of miR-22 and miR-135a, respectively. The results showed that the expression levels of miR-22 and miR-135a were obviously increased in AEP group compared with the control group in in-vivo and in-vitro models. The expression levels of miR-22 and miR-135a were elevated conspicuously and the expression levels of their target genes were reduced significantly in AR42J cells transfected with lentiviruses carrying the miRNA mimic. The apoptosis rate was much higher in the TNF-α-induced cells than in non-treated cells. The AR42J cells transfected with miRNA AMOs expressed lower level of miR-22 and miR-135a and had lower apoptosis rate, but the expression levels of ErbB3 and Ptk2 were increased obviously. It was concluded that the expression levels of miR-22 and miR-135a were elevated in AEP. Up-regulating the expression of miR-22 and miR-135a may promote the apoptosis of pancreatic acinar cells by repressing ErbB3 and Ptk2 expression in AEP.

Upregulation of epidermal growth factor receptor 4 in oral leukoplakia / 国际口腔科学杂志·英文版

In the present study, we investigate the expression profile of the epidermal growth factor receptor family, which comprises EGFR/ErbB1, HER2/ErbB2, HER3/ErbB3 and HER4/ErbB4 in oral leukoplakia (LP). The expression of four epidermal growth factor receptor (EGFR) family genes and their ligands were measured in LP tissues from 14 patients and compared with levels in 10 patients with oral lichen planus (OLP) and normal oral mucosa (NOM) from 14 healthy donors by real-time polymerase chain reaction (PCR) and immunohistochemistry. Synchronous mRNA coexpression of ErbB1, ErbB2, ErbB3 and ErbB4 was detected in LP lesions. Out of the receptors, only ErbB4 mRNA and protein was more highly expressed in LP compared with NOM tissues. These were strongly expressed by epithelial keratinocytes in LP lesions, as shown by immunohistochemistry. Regarding the ligands, the mRNA of Neuregulin2 and 4 were more highly expressed in OLP compared with NOM tissues. Therefore, enhanced ErbB4 on the keratinocytes and synchronous modulation of EGFR family genes may contribute to the pathogenesis and carcinogenesis of LP.

Clinical significance of human epidermal growth factor receptor family molecules expression in gastric cancer / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To study the association of human epidermal growth factor receptor family molecules expression in gastric cancer tissues with the prognosis of patients with gastric cancer.</p><p><b>METHODS</b>Clinical data of 161 patients with gastric cancer undergoing gastrectomy in Jiangsu Cancer Hospital between January 2006 and January 2007 were analyzed retrospectively. The expression of HER1, HER2, HER3 and HER4 was detected by immunohistochemistry. Association of the expression of HER family with the prognosis of patients was examined. Kaplan-Meier method was used to analyze the survival.</p><p><b>RESULTS</b>High expression rates of HER1, HER2, HER3 and HER4 were 46.0% (74/161), 10.6% (17/161),55.9% (90/161) and 68.3% (110/161) respectively. Univariate analysis revealed that high expression of HER3 was associated with tumor invasion depth, lymph node metastasis, stage, neurovascular invasion, and overall 4-year survival. High expression of HER4 was associated with tumor distant metastasis and stage. High co-expression of HER2 and HER3 was associated with overall 4-year survival (P=0.023). Multivariate analysis revealed that high expression of HER3 and stage were prognostic independent factors.</p><p><b>CONCLUSION</b>Up-regulated expression of HER3 is associated with the poor prognosis in gastric cancer patients.</p>

HER3 intracellular domains play a crucial role in HER3/HER2 dimerization and activation of downstream signaling pathways

Dimerization among the EGFR family of tyrosine kinase receptors leads to allosteric activation of the kinase domains of the partners. Unlike other members in the family, the kinase domain of HER3 lacks key amino acid residues for catalytic activity. As a result, HER3 is suggested to serve as an allosteric activator of other EGFR family members which include EGFR, HER2 and HER4. To study the role of intracellular domains in HER3 dimerization and activation of downstream signaling pathways, we constructed HER3/HER2 chimeric receptors by replacing the HER3 kinase domain (HER3-2-3) or both the kinase domain and the C-terminal tail (HER3-2-2) with the HER2 counterparts and expressed the chimeric receptors in Chinese hamster ovary (CHO) cells. While over expression of the intact human HER3 transformed CHO cells with oncogenic properties such as AKT/ERK activation and increased proliferation and migration, CHO cells expressing the HER3-2-3 chimeric receptor showed significantly reduced HER3/HER2 dimerization and decreased phosphorylation of both AKT and ERK1/2 in the presence of neuregulin-1 (NRG-1). In contrast, CHO cells expressing the HER3-2-2 chimeric receptor resulted in a total loss of downstream AKT activation in response to NRG-1, but maintained partial activation of ERK1/2. The results demonstrate that the intracellular domains play a crucial role in HER3's function as an allosteric activator and its role in downstream signaling.

A functional comparison between the HER2high/HER3 and the HER2low/HER3 dimers on heregulin-beta1-induced MMP-1 and MMP-9 expression in breast cancer cells

Overexpression of HER2 correlates with more aggressive tumors and increased resistance to cancer chemotherapy. However, a functional comparison between the HER2high/HER3 and the HER2low/HER3 dimers on tumor metastasis has not been conducted. Herein we examined the regulation mechanism of heregulin-beta1 (HRG)-induced MMP-1 and -9 expression in breast cancer cell lines. Our results showed that the basal levels of MMP-1 and -9 mRNA and protein expression were increased by HRG treatment. In addition, HRG-induced MMP-1 and -9 expression was significantly decreased by MEK1/2 inhibitor, U0126 but not by phosphatidylinositol 3-kinase (PI-3K) inhibitor, LY294002. To confirm the role of MEK/ERK pathway on HRG-induced MMP-1 and -9 expression, MCF7 cells were transfected with constitutively active adenoviral-MEK (CA-MEK). The level of MMP-1 and -9 expressions was increased by CA-MEK. MMP-1 and -9 mRNA and protein expressions in response to HRG were higher in HER2 overexpressed cells than in vector alone. The phosphorylation of HER2, HER3, ERK, Akt, and JNK were also significantly increased in HER2 overexpressed MCF7 cells compared with vector alone. HRG-induced MMP-1 and -9 expressions were significantly decreased by lapatinib, which inhibits HER1 and HER2 activity, in both vector alone and HER2 overexpressed MCF7 cells. Finally, HRG-induced MMP-1 and MMP-9 expression was decreased by HER3 siRNA overexpression. Taken together, we suggested that HRG-induced MMP-1 and MMP-9 expression is mediated through HER3 dependent pathway and highly expressed HER2 may be associated with more aggressive metastasis than the low expressed HER2 in breast cancer cells.

Correlation of epidermal growth factor receptor mutations and HER2/3 protein expression with clinical outcome in advanced non-small cell lung cancer patients treated with gefitinib / 癌症

<p><b>BACKGROUND AND OBJECTIVE</b>The effect of gefitinib on advanced non-small cell lung cancer (NSCLC) was various. How to choose the sensitive patients and improve the effect was difficulty in clinic. This study was to assess the correlation of epidermal growth factor receptor (EGFR) mutations and HER2/3 protein expression with the effect of gefitinib on Chinese patients with advanced NSCLC.</p><p><b>METHODS</b>From May 2002 to February 2005, a total of 106 Chinese NSCLC patients who had failed at least one chemotherapy regimen were treated with gefitinib 250 mg once a day. The mutations in the exons 18-24 of EGFR gene were detected in the tumor tissues from 106 patients before the treatment of gefitinib, and HER2/3 expression in 84 tumor samples were detected by immunohistochemistry.</p><p><b>RESULTS</b>Mutation was identified in 32 (30.2%) tumor tissues. Overall remission rate was significantly higher in the HER2 high expression patients than in the HER2 low expression patients (36.8% vs 17.4%, P=0.044). HER2 and HER3 expression levels were not associated with time to progression (TTP) and overall survival (OS). The patients with HER2/3 single high expression had relatively longer TTP and OS than those with HER2/3 single low expression (6.1 vs 9.1 months, P=0.725; 6.1 vs 9.0 months, P=0.862), while those with concomitant HER2/3 high expression had significant longer TTP and OS. EGFR-mutated patients with HER2 expression or high HER2 and HER3 expressions were more sensitive to gefitinib.</p><p><b>CONCLUSION</b>EGFR mutations combined with HER2/3 expressions is a significant predictor for gefitinib efficacy on Chinese patients with advanced NSCLC.</p>

Expression and significance of ErbB3 and ErbB4 in patients with laryngeal squamous cell carcinomas / 临床耳鼻咽喉头颈外科杂志

OBJECTIVE@#To explore expression of ErbB3 and ErbB4 genes in laryngeal squamous cell carcinomas and their relation with the biological and clinicopathological parameters.@*METHOD@#Expression of ErbB3 and ErbB4 mRNA in 36 cases of laryngeal carcinomas and normal mucosa of incisal margin, 11 cases of benign proliferative lesions were examined by reverse transcription polymerase chain reaction (RT-PCR).@*RESULT@#In laryngeal carcinomas and benign proliferative lesions, over-expressive positive ratios of ErbB3 were 66.7%, 18.2% respectively (P 0.05). Differences of expressive level of ErbB3 and ErbB4 were not significant between laryngeal carcinoma and normal mucous of incisal margin (P > 0.05). In addition, expressive level of ErbB3 and ErbB4 were not associated with diversity of clinical pathologic characters (P > 0.05).@*CONCLUSION@#ErbB3 and ErbB4 genes play different role in carcinogenesis and development, and relate to the reoccurrence of carcinoma.

Expressions of tumor necrosis factor-converting enzyme and ErbB3 in rats with chronic obstructive pulmonary disease / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Chronic obstructive pulmonary disease (COPD) is associated not only with airway inflammation characterized by mucin hypersecretion but also with systemic inflammation. Tumor necrosis factor alpha (TNF-alpha) is found to take part in systemic inflammation, and ErbB3 plays an important role in mucin hypersecretion of COPD. Since TNF-alpha converting enzyme (TACE) is involved in the activation of both TNF-alpha and ErbB3, we established rat models of COPD to investigate the expressions of TACE, TNF-alpha and ErbB3 and to explore the correlations among TACE, TNF-alpha and ErbB3 respectively.</p><p><b>METHODS</b>Thirty Wistar male rats were randomly divided into COPD group (group C, n = 10), saline solution parallel group (group P, n = 8), and normal control group (group N, n = 8). Group C was challenged with passive cigarette smoking and intratracheal instillation of lipopolysaccharide. Six weeks later pulmonary functions were tested, bronchoalveolar fluid and arterial blood gases were assayed, and histopathological evaluations were performed in turn. The expressions of TACE, TNF-alpha and ErbB3 in lungs of all rats were determined histochemically.</p><p><b>RESULTS</b>The expressions of TACE, TNF-alpha and ErbB3 were significantly higher in group C than in group N (P < 0.01). The contents of TNF-alpha in serum (P < 0.01) and bronchoalveolar lavage fluid (BALF) (P < 0.01) were elevated more significantly in group C than in group N. A positive correlation existed between TACE and TNF-alpha (r = 0.784, P < 0.01) and between TACE and ErbB3 (r = 0.526, P < 0.01) respectively.</p><p><b>CONCLUSIONS</b>TNF-alpha and ErbB3 are involved in the pathogenesis of COPD. TACE contributes to the progress of COPD indirectly through the function of TNF-alpha and ErbB3.</p>

Relation between c-erbB1, c-erbB2, MAPK expression and resistance to tamoxifen in breast cancer cells in vitro / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To study the growth regulation pathway and the mechanism of acquired resistance to tamoxifen (TAM) in breast cancer cells.</p><p><b>METHODS</b>TAM was used to induce wild-type MCF-7 human breast cancer cell line and establish a tamoxifen-resistant (TAM-R) cell line. RT-PCR, Western blot and immuocytochemical techniques were used to detect and compare mRNA and protein of c-erbB1, cerbB2, c-erbB3, c-erbB4 in wild-type MCF-7 and TAM-R MCF-7 cell lines.</p><p><b>RESULTS</b>Compared with wild-type MCF-7 cells, the mRNA of c-erbB1 increased 6 times (P < 0.05) and the protein 3 times higher (P < 0.05), and the mRNA of c-erbB2 increased 3 times (P < 0.05) and the protein 1.5 times higher (P < 0.05) in TAM-R MCF-7 cells. However, comparable levels of c-erbB3 mRNA and protein were expressed in both cell lines. c-erbB4 could not be detected. Under basic conditions, phosphorylated c-erbB1/c-erbB2 and c-erbB1/c-erbB3 heterodimers but not c-erbB2/c-erbB3 receptor heterodimers were detected in TAM-R cells in association with increased level of phosphorylated MAPK.</p><p><b>CONCLUSION</b>Our findings demonstrated that the development of TAM-resistance in MCF-7 cells is related with the autocrine release and action of an c-erbB1-specific ligand inducing preferential c-erbB1/c-erbB2 dimerization and downstream activation of the MAPK pathway.</p>

Overexpression of type I growth factor receptors in pterygium / 中华医学杂志(英文版)

<p><b>OBJECTIVE</b>To evaluate the expression of the type I growth factor receptor family [epidermal growth factor receptor (EGFR), ErbB2 and ErbB3] by the epithelial cells in pterygium.</p><p><b>METHODS</b>Immunoflourescent staining and Western blotting were performed to detect the expression pattern and quantity of EGFR, ErbB2 and ErbB3 proteins in the epithelia of 15 patients with primary pterygium and 12 subjects with normal conjunctiva.</p><p><b>RESULTS</b>In immunofluorescent staining, the EGFR protein was present in the basal cells while the ErbB2 and ErbB3 were expressed by the superficial cells in normal conjunctival epithelium. Of the pterygium cases 15, 11 were stained by EGFR, ErbB2 and ErbB3 in the full thickness of the epithelium and showed stronger staining compared with the control group. Four of them showed a similar staining pattern to the normal conjunctiva group. The density of protein bands detected by Western blotting for all three growth factor receptors was consistent with the immunofluorescent staining. Compared with normal conjunctiva, stronger protein bands of these three receptors were found in all of the pterygium specimens, in which EGFR, ErbB2 and ErbB3 were expressed in the full thickness, as shown by immunofluorescent staining.</p><p><b>CONCLUSIONS</b>The increased expression of EGFR, ErbB2 and ErbB3 proteins was present in pterygium, which indicated that pterygium is a disorder with abnormal proliferation. The abnormal expression of EGFR, ErbB2 and ErbB3 by the epithelium and the communication with cytokines in the stroma in pterygium may be a key pathogenic factor in this disorder.</p>