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1.
We previously demonstrated that expression of androgen receptor (AR) by transfection of the androgen-independent prostate cancer cell line PC3 decreases invasion and adhesion of these cells (PC3-AR) through modulation of alpha6beta4 integrin expression. The treatment with androgens further reduced invasion of the cells without modifying alpha6beta4 expression, suggesting an interference with the invasion process by androgens. Here, we investigated EGF-mediated signal transduction processes that lead to invasion in PC3-AR cells. We show that EGF-induced EGFR autotransphosphorylation is reduced in PC3-AR cells compared to PC3 cells transfected only with the vector (PC3-Neo). EGF-stimulated PI3K activity, a key signaling pathway for invasion of these cells, and EGF-PI3K interaction are also decreased in PC3-AR cells and further reduced by treatment with androgen. Finally, we show that EGFR internalization process was reduced in PC3-AR and LNCaP cells compared to PC3-Neo. Investigations on the location of AR in PC3-AR transfected cells were also conducted. Immunoconfocal microscopy and coimminoprecipitation studies demonstrated the presence of an interaction between EGFR and AR at membrane level in PC3-AR and LNCaP cells. In conclusion, our results suggest that the expression of AR by transfection in PC3 cells confers a less-malignant phenotype by interfering with EGFR signaling leading to invasion through a mechanism involving an interaction between AR and EGFR.  相似文献   

2.
Despite multiple reports of overexpression in prostate cancer (PC), the reliance of PC cells on activated epidermal growth factor receptor (EGFR) and its downstream signaling to phosphoinositide 3'-kinase/Akt (PI3K/Akt/PTEN) and/or mitogen-activated protein kinase (MAPK/ERK) pathways has not been fully elucidated. In this study, we compared the role of EGF-mediated signaling in nonmalignant (BPH-1, PNT1A, and PNT1B) and PC cell lines (DU145, PC3, LNCaP, and CWR22Rv1). EGF-induced proliferation was observed in all EGFR-expressing PC cells except PC3, indicating that EGFR expression does not unequivocally trigger proliferation following EGF stimulation. ErbB2 recruitment potentiated EGF-induced signals and was associated with the most pronounced effects of EGF despite low EGFR expression. In this way, the sum of EGFR and ErbB2 receptor phosphorylation proved to be a more sensitive indicator of EGF-induced proliferation than quantification of the expression of either receptor alone. Both Akt and ERK were rapidly phosphorylated in response to EGF, with ERK phosphorylation being the weakest in PC3 cells. Extrapolation of these findings to clinical PC suggests that assessment of phosphorylated EGFR + ErbB2 together could serve as a marker for sensitivity to anti-EGFR-targeted therapies.  相似文献   

3.
Dysregulation of endocytosis was viewed as an emerging feature of cancer development and progression. A large GTPase dynamin2 plays a significant role in receptor tyrosine kinases (RTKs) endocytosis. The study was designed to investigate its roles in hepatocellular carcinoma (HCC) metastasis and its underlying mechanism. Dynamin2 expression in cancer tissues from HCC patients was assessed by immunohistochemistry and its prognostic significance for the patients was conducted using univariate and multivariate analysis. Its role in tumor invasion and metastasis was evaluated in vitro by gene silence using siRNA-mediated approach and the small molecule inhibitor of Dynasore. EGFR expression in HCC cell lines and EGFR downstream signaling ERK1/2 was evaluated by Western-blot and immunofluorescence analyses after Dynamin2 inhibition. Our data indicated that low expression of dynamin2 was well correlated with invasion characteristics and shorter overall survival. HCC cell migration, colony formation and invasion were significantly increased after the inhibition of dynamin2 in HCC cells. Internalization of EGFR was markedly reduced when dynamin2 was knock down or inhibition. In addition, we observed that dynamin2 regulated EGF mediated EGFR downstream Ras/ERK1/2 signaling and p-ERK1/2 accumulation in nucleus. The results demonstrate a possible mechanism of dynamin involved EGFR endocytosis and modulation of metastasis in HCC. Dynamin2 inhibits the invasion and metastasis of HCC cells by the promotion of EGFR endocytosis and downregulation of ERK1/2 phosphorylation.  相似文献   

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C D Wolfgang  M Essand  B Lee  I Pastan 《Cancer research》2001,61(22):8122-8126
Previously, we showed that prostate and prostate cancer cells express a truncated T-cell receptor gamma chain mRNA that uses an alternative reading frame to produce a novel nuclear T-cell receptor gamma chain alternate reading frame protein (TARP). TARP is expressed in the androgen-sensitive LNCaP prostate cancer cell line but not in the androgen-independent PC3 prostate cancer cell line, indicating that TARP may play a role in prostate cancer progression. To elucidate the function of TARP, we generated a stable PC3 cell line that expresses TARP in a constitutive manner. Expression of TARP in PC3 cells resulted in a more rapid growth rate with a 5-h decrease in doubling time. cDNA microarray analysis of 6538 genes revealed that caveolin 1, caveolin 2, amphiregulin, and melanoma growth stimulatory activity alpha were significantly up-regulated, whereas IL-1beta was significantly down-regulated in PC3 cells expressing TARP. We also demonstrated that TARP expression is up-regulated by testosterone in LNCaP cells that express a functional androgen receptor. These results suggest that TARP has a role in regulating growth and gene expression in prostate cancer cells.  相似文献   

6.
The metabolism of arachidonic acid by either the cyclooxygenase (COX) or lipoxygenase (LOX) pathway generates eicosanoids, which have been implicated in the pathogenesis of a variety of human diseases, including cancer. They are believed to play important roles in tumor promotion, progression, and metastasis. Involvement of LOXs expression and function in tumor growth and metastasis has been reported in human tumor cell lines. Expressions of 5- and 12-LOX in prostate cancer (PC) patients, prostatic intraepithelial neoplasia (PIN), benign prostatic hyperplasia (BPH), and normal prostate (NP) tissues were examined, as well as effects of their inhibitors on cell proliferation in 2 PC cell lines (PC3, DU-145). Expression of 5- and 12-LOX protein was detected by immunohistochemistry. Effects of LOX inhibitors on prostate cancer cell growth were examined by MTT assay, and Hoechst staining was used to determine whether or not the LOX inhibitors induce apoptosis. While 5- and 12-LOX expressions were slightly detected in BPH and NP tissues, marked expressions of 5- and 12-lipoxygenase were detected in PIN and PC tissues. The LOX inhibitors caused marked reduction of prostate cancer cells in a concentration- and time-dependent manner. The LOX inhibitors caused marked inhibition of PC cells through apoptosis. LOX is induced in prostate cancer, and our results suggest that LOX inhibitors may mediate potent antiproliferative effects against prostate cancer cells. Thus, LOX may become a new target in treatment of prostate cancer.  相似文献   

7.
The deregulation of the epidermal growth factor receptor (EGFR) pathway plays a major role in the pathogenesis of prostate cancer (PCa). However, therapies targeting EGFR have demonstrated limited effectiveness in PCa. A potential mechanism to overcome EGFR blockade in cancer cells is the autocrine activation of alternative receptors of the human EGFR (HER) family through the overexpression of the HER receptors and ligands. In the present study, we were interested in analyzing if this intrinsic resistance mechanism might contribute to the inefficacy of EGFR inhibitors in PCa. To this end, we selected two androgen-independent human prostate carcinoma cell lines (DU145 and PC3) and established DU145 erlotinib-resistant cells (DUErR). Cells were treated with three EGFR inhibitors (cetuximab, gefinitib and erlotinib) and the sensitivity to each treatment was assessed. The gene expression of the four EGFR/HER receptors and seven ligands of the HER family was analyzed by real-time PCR prior to and after each treatment. The receptors expression and activation were further characterized by flow cytometry and western blot analysis. EGFR inhibition rapidly induced enhanced gene expression of the EGF, betacellulin and neuregulin-1 ligands along with HER2, HER3 and HER4 receptors in the DU145 cells. In contrast, slight changes were observed in the PC3 cells, which are defective in the phosphatase and tensin homolog (PTEN) tumor suppressor gene. In the erlotinib-resistant DUErR cells, the expression of HER2 and HER3 was increased at mRNA and protein levels together with neuregulin-1, leading to enhanced HER3 phosphorylation and the activation of the downstream PI3K/Akt survival pathway. HER3 blockage by a monoclonal antibody restored the cytostatic activity of erlotinib in DUErR cells. Our results confirm that the overexpression and autocrine activation of HER3 play a key role in mediating the resistance to EGFR inhibitors in androgen-independent PCa cells.  相似文献   

8.
Activation of EGFR signaling pathway leads to prostate cancer bone metastasis; however, therapies targeting EGFR have demonstrated limited effectiveness and led to drug resistance. miR-203 levels are down-regulated in clinical samples of primary prostate cancer and further reduced in metastatic prostate cancer. Here we show that ectopic miR-203 expression displayed reduced bone metastasis and induced sensitivity to tyrosine kinase inhibitors (TKIs) treatment in a xenograft model. Our results demonstrate that the induction of bone metastasis and TKI resistance require miR-203 down-regulation, activation of the EGFR pathway via altered expression of EGFR ligands (EREG and TGFA) and anti-apoptotic proteins (API5, BIRC2, and TRIAP1). Importantly, a sufficient reconstitution of invasiveness and resistance to TKIs treatment was observed in cells transfected with anti-miR-203. In prostate cancer patients, our data showed that miR-203 levels were inversely correlated with the expression of two EGFR ligands, EREG and TGFA, and an EGFR dependent gene signature. Our results support the existence of a miR-203, EGFR, TKIs resistance regulatory network in prostate cancer progression. We propose that the loss of miR-203 is a molecular link in the progression of prostate cancer metastasis and TKIs resistance characterized by high EGFR ligands output and anti-apoptotic proteins activation.  相似文献   

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In a series of 111 patients with squamous cell carcinoma (SCC), we used immunohistochemistry to examine the expression levels of four epidermal growth factor receptor (EGFR) family members (EGFR, HER-2/neu, HER-3, and HER-4). Expression of the EGFR members was not significantly associated with tumor size. However, their expressions (except for HER-4) were significantly associated with the presence of lymph node metastasis, and all of them were significantly associated with distant metastasis. We further examined the association between the expression levels of the EGFR members and the survival rates in 47 oral SCC patients whose detailed clinical follow-ups were available. The expression of all EGFR members was significantly associated with shortened patient survival, and the association was strongest for HER-2/neu. Furthermore, the combination of HER-2, HER-3, and EGFR but not HER-4 significantly improved the predicting power. The expression level of HER-2/neu was significantly correlated with that of EGFR or HER-3. Similar coexpression patterns were also observed in three oral SCC cell lines studied, but not in four other head and neck SCC cell lines. Taken together, these results indicated that expression levels of EGFR, HER-2/ neu, and HER-3 may help predict the outcome of patients with oral SCC.  相似文献   

11.
潘剑  韦煜  叶定伟  朱耀 《中国癌症杂志》2021,31(11):1104-1109
背景与目的:表皮生长因子受体(epidermal growth factor receptor,EGFR)基因的高表达被证明在前列腺癌中可间接促进肿瘤细胞迁移,并与较短的无转移生存期相关。但此前对于EGFR基因的研究主要集中于机制方面,很少与临床指标建立联系。对比EGFR基因在西方国家和中国前列腺癌患者中基因型的差异,同时探讨临床病理学特征与EGFR基因多态性的相关性。方法:检测EGFR(rs884419)基因在复旦大学附属肿瘤医院2014—2019年连续收治的182例前列腺癌患者外周血白细胞DNA中的多态性情况,比较中国与西方人群基因型变异的差异,并比较基因型与临床病理学特征及基线特征的相关性。结果:与EGFR(rs884419)基因型为AA和AG的变异组患者相比,基因型为GG的正常组患者在初诊时为M 1期的占比更高(65.3% vs 84.2%,P < 0.05)。EGFR(rs884419)基因多态性与确诊时年龄、确诊时前列腺特异性抗原、转移负荷及Gleason评分无相关性(P > 0.05)。与美国前列腺癌患者相比,EGFR(rs884419)基因的变异频率更高(20.4% vs 79.1%,P < 0.05)。结论:EGFR基因型正常组患者初诊时M 1 期占比较变异组高,提示EGFR基因的表达差异可能参与前列腺癌转移的发生、发展过程,根据基因型理论上可以预测患者初诊时的远处转移状态;同时,与西方人群相比,中国前列腺癌患者EGFR基因的变异频率较高,对确诊后治疗效果的预测效能会更高。  相似文献   

12.
The epidermal growth factor receptor (EGFR) is highly expressed in gastric cancer indicating its suitability as a target for receptor tyrosine kinase (RTK) inhibitors. In the current study we explored the role of EGFR and its potential use as a therapeutic target in gastric cancer. First we analyzed 66 gastric cancer samples of Asian and Caucasian patients for the presence of EGFR mutations. No activating EGFR mutations were found and gefitinib alone was only weakly effective in gastric cancer cell lines. However, acetylsalicylic acid (ASA) significantly enhanced the inhibitory effects of gefitinib indicating synergistic action. Whole genome expression profiling indicated significant regulation of 120 genes in the case of co-administration of gefitinib and ASA (32 induced, 88 repressed) in gastric adenocarcinoma cells. Further analyses indicated that several important signalling pathways were effectively inhibited by simultaneous exposure to gefitinib and ASA. Our findings indicate that although gastric cancer does not seem to harbour mutations which render the cancer cells constitutively susceptible to gefitinib, the co-administration of ASA can strengthen RTK inhibitor activity in adenocarcinoma cells by EGFR activation. This is the first report of effective modulation of EGFR-inhibition activity in cancer.  相似文献   

13.
Despite the fact that tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) can selectively induce apoptosis in cancer cells, TRAIL resistance in cancer cells has challenged the use of TRAIL as a therapeutic agent. First, prostate carcinoma cell lines (DU145, LNCaP and PC3) were screened for sensitivity to adenovirus delivery of TRAIL (Ad5hTRAIL). As amplified Ikappa B kinase (IKK) activity is responsible for the constitutive nuclear factor-kappaB (NF-kappaB) activation leading to uncontrolled cell growth and metastasis, a dual vector approach using both an adenovirus vector (Ad) expressing the dominant-negative mutant of IKKbeta (AdIKKbetaKA) and Ad5hTRAIL was employed to determine if prostate cancer cells were sensitized to TRAIL in the setting of IKK inhibition. Inhibition of the NF-kappaB pathway through IKK blockade sensitized all three prostate cancer cell lines to TRAIL, regardless of NF-kappaB activation or decoy receptor gene expression. Moreover, a novel quantitative real-time RT-PCR assay and conventional flow cytometry analysis indicated that TRAIL-resistant DU145 and LNCaP cells, but not TRAIL-sensitive PC3 cells, expressed substantial amounts of TRAIL Decoy Receptor 4. In conclusion, TRAIL decoy receptor expression appeared to be the chief determinant of TRAIL resistance encountered in prostate carcinoma cell lines.  相似文献   

14.
15.
[目的]分析雌激素受体α、β(ERα、ERβ)和表皮生长因子受体(EGFR)在非小细胞肺癌(NSCLC)组织中的表达及其临床意义。[方法]采用MaxVision免疫组织化学技术检测59例NSCLC石蜡包埋组织中ERα、ERβ和EGFR的表达。[结果](1)ERα在肺癌组织及癌旁组织中均未见表达。ERβ在NSCLC中的阳性表达率为45.8%(27/59),EGFR在NSCLC中的阳性表达率为64.4%(38/59),而在癌旁组织中未见ERβ和EGFR的表达。(2)ERβ阳性表达与NSCLC组织学类型有关,在腺癌组织中的表达明显高于鳞癌,与性别、年龄、肿瘤大小、分化程度、TNM分期、淋巴结转移及吸烟状况无关;EGFR阳性表达与肿瘤组织的TNM分期及淋巴结转移相关,与性别、年龄、肿瘤大小、组织学类型、分化程度及吸烟状况无关。(3)腺癌中EGFR阳性表达并ERβ阳性表达与鳞癌相比有显著性差异。[结论]ERβ和EGFR可能在肺癌,尤其是腺癌的发生发展中发挥协同作用,由此可以通过同时靶向两个信号通路来治疗NSCLC。  相似文献   

16.
Gefitinib (Iressa)–a specific inhibitor of epidermal growth factor receptor (EGFR) tyrosine kinase–has been shown to suppress the activation of EGFR signaling required for cell survival and proliferation in non-small cell lung cancer (NSCLC) cell lines. We recently provided novel evidence that gefitinib-sensitive PC9 cells show normal endocytosis of EGFR: internalized EGF-EGFR complexes were transported to late endosomes/lysosomes 15 min after EGF stimulation, and then degraded within the lysosomes. However, gefitinib-resistant QG56 cells showed internalized EGFR accumulation in early endosomes after 60 min of internalization, instead of its trafficking to lysosomes, indicating an aberration in some steps of EGF-EGFR trafficking from the early endosomes to late endosomes/lysosomes. Therefore, we postulate that impairment in some steps of EGF-EGFR trafficking from early endosomes to late endosomes/lysosomes might confer gefitinib-resistance in NSCLC cell lines. To further substantiate the detailed internalization mechanism of gefitinib-sensitive and gefitinib-resistant cells, using confocal immunofluorescence microscopy, we examined the endocytic trafficking of phosphorylated EGFR (pEGFR) in the absence or presence of gefitinib. In PC9 and QG56 cells without EGF stimulation, a large number of pEGFR-positive small vesicular structures not colocalized with late endosomes/lysosomes were spread throughout the cytoplasm, and some pEGFR staining was distributed in the nucleus. This implies a novel intracellular trafficking pathway for pEGFR from cytoplasmic vesicles to the nucleus. Furthermore, an aggregated vesicular structure of early endosomes was observed in the perinuclear region of QG56 cells; it was revealed to be associated with SNX1, originally identified as a protein that interacts with EGFR. Therefore, we confirmed our previous data that an aberration in some steps of EGF-EGFR trafficking from the early endosomes to late endosomes/lysosomes occurs in QG56 cells. Furthermore, in PC9 cells, efficient phosphorylation of EGFR and rapid internalization of pEGFR was observed at 3 min after EGF stimulation; these internalized pEGFR-positive vesicles were trafficked to late endosomes at 15 min, indicating rapid trafficking of EGF-pEGFR complexes from early to late endosomes in PC9 cells. Gefitinib treatment strongly reduced the phosphorylation level of EGFR, and subsequent endocytosis of EGFR was significantly suppressed in PC9 cells. In contrast, in QG56 cells, EGFR trafficking via the early endocytic pathway was basically impaired; therefore, gefitinib appeared to slightly suppress the internalization of pEGFR. Collectively, our data provide novel evidence that extensive impairment in pEGFR endocytosis via the early endocytic pathway might confer gefitinib-resistance in QG56 cells.  相似文献   

17.
Siu A  Virtanen C  Jongstra J 《Oncotarget》2011,2(12):1134-1144
The PIM family of oncogenic serine/threonine kinases regulates tumour cell proliferation. To identify proliferative signaling pathways that are regulated by PIM kinases we analyzed gene expression differences in DU-145 and PC3 prostate cancer derived cells induced by treatment with the recently developed highly selective PIM kinase inhibitor M-110. This identified 97 genes the expression of which is affected by M-110 in both cell lines. We then focused on the M-110 induced up regulation of the MIG6 gene that encodes a negative regulator of EGFR signaling. Here we show that M-110 and the structurally unrelated PIM kinase inhibitor SGI-1776 up regulate MIG6 in DU-145 and PC3 cells. Knockdown of PIM-1 but not of PIM-2 or PIM-3 also up regulates MIG6 expression, which identifies MIG6 as a PIM-1 regulated gene. In agreement with the role of MIG6 protein as a negative regulator of EGFR signaling we found that M-110 treatment inhibits EGF induced EGFR activation and the activation of the downstream ERK MAPkinase pathway. The biological significance of these findings are demonstrated by the fact that co-treatment of DU-145 or PC3 cells with the EGFR tyrosine kinase inhibitor Gefitinib and M-110 or SGI-1776 has synergistic inhibitory effects on cell proliferation. These experiments define a novel biological function of PIM-1 as a co-regulator of EGFR signaling and suggest that PIM inhibitors may be used in combination therapies to increase the efficacy of EGFR tyrosine kinase inhibitors.  相似文献   

18.
Death from prostate cancer is most frequently a result of metastatic disease. A key step in the process of metastasis is the attachment of circulatory tumor cells to target organ endothelium. This process is thought to be mediated by lectins, a class of cell surface proteins that bind two or more carbohydrate groups. Using fluorescent microscopy and fluorescein isothiocyanate (FITC) conjugated lectins, the presence of various carbohydrates was examined in the following tumorigenic and non-tumorigenic cell lines: rat prostate epithelial (EPYP-2, EPYP-1), rat prostate endothelial (YPEN-2, YPEN-1, YPEN-2PV), Dunning rat prostate cancer cell lines (MLL, ML, AT6.3, AT.1, AT2.1, GP9F3), and three tumorigenic human prostate cell lines (LNCaP, PC3, PC3 bone). The lectin Triticum vulgaris (WGA) was found to readily bind the carbohydrates N-acetylglucosamine and sialic acid on the plasma membrane of tumorigenic cell lines. Interestingly, WGA bound carbohydrates located to the nucleus and cytoplasm in non-tumorigenic cell lines, indicating that N-acetylglucosamine and sialic acid residues are preferentially expressed on the cell membrane of prostate cancer cells. Lectin staining patterns in cell lines of varying metastatic potential revealed no significant difference between highly metastatic vs. low metastatic cell lines. Observations revealed an absence of N-acetylgalactosamine and L-fucose in all rat Dunning, epithelial and endothelial cell lines as well as all human prostate cancer cell lines except for the androgen insensitive human prostate cancer cell line PC3, in which L-fucose residues were detected in the nucleus and on the plasma membrane. PC3 bone cells, which metastasized selectively to bone, demonstrated the presence of galactose residues whereas PC3 cells did not, suggesting that preference for target organ endothelium may be influenced by the expression of carbohydrate residues. These data indicate that differential carbohydrate expression may play an important role in prostate cancer biology.  相似文献   

19.
Previous reports have shown elevated arginase activity in prostate cancer patients. This study was designed to compare expression levels of arginase II (AII) in various human prostate cancer cell lines and tissues. Expression levels of AII and other enzymes involved in arginine metabolism were examined in androgen-dependent (LNCaP, LAPC-4) and androgen-independent (PC3, DU145, CL-1, CL-2) prostate cancer cell lines by real-time RT-PCR and Western blot analysis. Further expression analysis of AII was accomplished by immunohistochemical staining of a tissue microarray comprised of 246 primary prostatectomy specimens. In addition, polyamine levels were measured within the prostate cancer cell lines by HPLC. Total polyamines were significantly lower in the androgen-dependent cell lines compared to the androgen-independent cell lines. AII expression was found to be most prominent in the androgen-dependent cell lines and least prominent in the androgen-independent cell lines. Additionally, we found expression of ornithine aminotransferase (OAT), an enzyme also responsible for ornithine production, to be inversely correlated with AII expression. The tissue microarray data revealed that the highest AII expression was seen in BPH, followed by PIN and normal samples, with the lowest expression levels observed in prostate cancer tissues. Moreover, we observed an expression gradient across Gleason grades revealing stronger AII expression in low-grade tumors. The polyamine data, combined with the expression analysis studies, support a possible correlation between AII, OAT, and polyamine synthesis. Based on these results, arginase II expression may play a role in prostate cancer progression. More specifically, the elevated AII expression seen in androgen-dependent and in more differentiated prostate cancers suggests that AII could be a potentially useful marker of early stage prostate adenocarcinoma.  相似文献   

20.
目的:检测CD73过表达对前列腺癌细胞增殖、迁移、侵袭能力的影响,并对其作用机制进行初步探讨。方法:以PC3细胞为研究对象,利用CD73过表达慢病毒转染PC3细胞,构建CD73过表达的PC3-CD73细胞模型,利用实时细胞分析系统检测CD73对PC3细胞增殖能力的影响,划痕修复实验检测CD73对PC3细胞迁移能力的影响,Transwell实验检测CD73对PC3细胞侵袭能力的影响,实时荧光定量PCR检测CD73对肿瘤细胞增殖、迁移相关分子表达水平的影响。结果:CD73过表达对PC3细胞的增殖具有显著的促进作用,然而对PC3细胞的迁移、侵袭无明显影响。实时荧光定量PCR结果显示CD73过表达对PC3细胞中EGFR、ERK、AKT以及EMT相关分子标志的表达水平无显著的影响。结论:CD73过表达通过EGFR/AKT通路以外的途径促进前列腺癌细胞增殖。  相似文献   

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