FOXO1在肾癌组织和细胞中的表达及临床意义

目的:探讨FOXO1在肾癌组织和细胞中的表达及其与肾癌发生发展的关系。方法:实时定量PCR和Western blot检测肾癌细胞中FOXO1 mRNA和蛋白的表达情况;免疫组化方法检测肾癌组织中FOXO1蛋白的表达;应用针对人FOXO1基因的小干扰RNA在体外转染769-P细胞;CCK8检测细胞增殖情况。结果:免疫组化结果显示透明细胞肾癌和乳头状细胞肾癌FOXO1的阳性率低于嫌色细胞肾癌（P＜0.05）;FOXO1蛋白的表达与透明细胞肾癌的分期、分级有关（P＜0.05）;769-P细胞FOXO1 mRNA和蛋白表达水平高于786-O和Caki-1细胞;利用特异性的siRNA抑制FOXO1 mRNA和蛋白表达后,发现769-P细胞的增殖加快。结论:FOXO1表达下降与肾癌的分型和透明细胞肾癌的分期、分级有关,FOXO1可作为肾癌诊断和预后的标志物及治疗的靶点。     

Differential expression of the enzyme that esterifies retinol, lecithin:retinol acyltransferase, in subtypes of human renal cancer and normal kidney.

PURPOSE: Retinoids, a group of compounds, including vitamin A (retinol), and related metabolites, have been shown to regulate the growth and differentiation of many types of cells. IFN-alpha and either 13-cis-retinoic acid or liposomal all-trans retinoic acid have been used in the treatment of patients with metastatic renal cell carcinoma. We knew that samples from renal cell carcinomas contained greatly reduced levels of retinol and retinyl esters relative to samples from normal human kidney. This prompted us to examine the levels of LRAT (lecithin:retinol acyltransferase) protein in various subtypes of human kidney cancers relative to normal human kidney by immunohistochemistry. EXPERIMENTAL DESIGN: We examined 31 partial or radical nephrectomy specimens diagnosed with kidney tumors between 1997 and 1998. Representative paraffin-embedded tissue blocks from each tumor, with each containing adjacent nonneoplastic renal parenchyma, were used for immunohistochemical analysis with affinity purified antibodies to human LRAT protein. RESULTS: LRAT protein was detected at high levels in the epithelial cells in the tubules and the lining of Bowman's capsule in the glomeruli of normal, nonneoplastic kidney sections. Among the 31 tumors, there were 13 cases of conventional (clear cell) renal cell carcinoma (RCC; including 2 multilocular cystic RCCs), 7 papillary RCC, 6 chromophobe RCC, 1 RCC, unclassified, and 4 renal oncocytoma. All tumors showed diffuse immunoreactivity for LRAT. In each case, the staining was uniform throughout the tumor, with only minimal variation in the staining intensity between different areas. All 4 renal oncocytomas, 2 of 6 chromophobe RCCs, 1 conventional (clear cell) carcinoma, 1 RCC, unclassified, and 2 conventional RCCs, which were of the multilocular cystic-type stained strongly (3+) for LRAT. In contrast, the remaining conventional RCCs and the papillary RCC samples stained much less intensely for LRAT. Of the 10 tumors that stained 3+ for LRAT in the study, 9 were either benign tumors or tumors with low malignant potential. CONCLUSIONS: These data show that LRAT expression is higher in renal tumors with an indolent biological behavior. Additional studies will ascertain if LRAT possesses any prognostic or therapeutic role in renal cancer.     

Regulation of the urokinase-type plasminogen activator system by the von Hippel-Lindau tumor suppressor gene.

The urokinase-type plasminogen activator (uPA) system plays an important role in tumor cell invasion, metastases, and angiogenesis. uPA, uPA receptor, and plasminogen activator inhibitor 1 (PAI-1) are prognostic factors in different solid tumors, e.g., renal cell carcinomas (RCCs). von Hippel-Lindau (VHL) disease is an inherited cancer syndrome that is characterized by extensively vascularized tumors, including hemangioblastomas and RCCs. In 75% of sporadic RCCs, the VHL gene is also inactivated. It has been recognized in sporadic RCC that PAI-1 mRNA levels are up-regulated and uPA mRNA levels are down-regulated. We determined the role of the VHL tumor suppressor gene in the regulation of the uPA system in RCC. In 786-O RCC cells expressing the wild-type (wt) VHL gene, we measured a 3-fold higher overall urokinase activity than in 786-O cells expressing a mutant VHL gene or lacking VHL. uPA mRNA and protein levels were higher in cells with wt VHL compared with cells with mutant VHL or lacking VHL. In addition, PAI-1 mRNA and protein levels were dramatically increased in 786-O cells with mutant VHL or lacking VHL, compared with cells expressing wt VHL. Our results provide further evidence that the VHL gene plays an important role in the process of angiogenesis by regulation of plasmin-mediated proteolysis of the extracellular matrix and may explain why VHL-induced RCCs grow slowly and metastasize relatively late.     

Expression of CIP2A in renal cell carcinomas correlates with tumour invasion, metastasis and patients' survival

Background:

Cancerous inhibitor of protein phosphatase 2A (CIP2A) drives cellular transformation. The objective of this study was to detect the potential effects of CIP2A in renal cell carcinomas (RCCs).

Methods:

A total of 107 RCC patients were involved in the study. Cancerous inhibitor of protein phosphatase 2A expression was investigated by real-time PCR and immunohistochemistry. In vitro, we examined the expression of CIP2A and c-Myc and tested the migration and invasion capability of A498 and KRC/Y cells with scratch migration assay and Matrigel invasion assay after down-regulating CIP2A expression using siRNA.

Results:

Cancerous inhibitor of protein phosphatase 2A was over-expressed in RCC tissues. Clear cell RCC showed an even higher-CIP2A expression level than papillary or chromophobe RCC did. The CIP2A immunostaining level was positively correlated with primary tumour stage, lymph node metastasis, distant metastasis, TNM stage and histological grade (all P<0.05). High-CIP2A expression implied poor survival for patients (P<0.05). Cancerous inhibitor of protein phosphatase 2A depletion by siRNA down-regulated c-Myc expression and attenuated the migration and invasion of RCC cells.

Conclusion:

Higher-CIP2A expression positively correlates with the aggressive phenotype of RCCs, and predicts poor prognosis for patients. Cancerous inhibitor of protein phosphatase 2A may be a novel target for prevention and treatment of RCC metastasis and recurrence.     

Overexpression of KIT in chromophobe renal cell carcinoma

We analysed gene-expression profiles in 15 surgical specimens of conventional, papillary, and chromophobe renal cell carcinomas (RCCs) using high-density oligonucleotide arrays. From about 12,000 genes targeted by the array, 67 were upregulated specifically in each histological type of RCC. The oncogene KIT was one of the genes whose expression was upregulated specifically in chromophobe RCCs. Immunohistochemical analysis demonstrated the KIT gene product on the cell membrane of chromophobe RCC in all cases, although it was not detected in conventional RCCs or non-neoplastic kidneys except for weak staining in the cytoplasm of renal tubules. These results suggest that each histological subtype of RCC has a unique gene-expression profile, and in particular indicates for the first time that KIT could be a useful marker for chromophobe RCC. As overexpression of KIT might be involved in tumor growth, KIT could be a new therapeutic target in this special type of RCC.     

Vascular cell adhesion molecule 1 predicts cancer-free survival in clear cell renal carcinoma patients.

PURPOSE: Vascular cell adhesion molecule 1 (VCAM1) is a cell surface glycoprotein implicated in various pathophysiologic conditions. We measured VCAM1 expression levels in tumor tissues and evaluated its significance and prognostic use in renal cell carcinoma (RCC). EXPERIMENTAL DESIGN: We used real-time quantitative PCR to examine the VCAM1 expression levels of a total of 485 sporadic renal tumors, including 429 clear cell, 21 papillary, 17 chromophobe, 11 oncocytomas, and 7 collecting duct carcinomas. We retrospectively examined the relationship of this expression to various clinicopathologic variables and the von Hippel-Lindau alteration status. We evaluated its significance with respect to patient survival rates using the Cox regression model combined with the split-sample method. RESULTS: Compared with normal kidney samples (n = 43), VCAM1 was significantly up-regulated in clear cell RCC and papillary RCC, whereas it was down-regulated in chromophobe RCC and oncocytoma. In clear cell RCC, VCAM1 expression levels were apparently high in patients asymptomatic at presentation and in patients with small tumor size, low-stage, low-grade, microvascular invasion-negative, and von Hippel-Lindau alteration-positive tumors. Univariate analyses showed that VCAM1 high expression is strongly associated with better outcomes in clear cell and papillary RCCs. Further, Cox multivariate analysis models combined with the split-sample method revealed that this association is significant only in cancer-free survival for patients with clear cell RCC after curative surgical resection. CONCLUSIONS: VCAM1 expression levels were found to be histologically subtype specific in renal tumors. Determination of the VCAM1 expression level as a biomarker can provide useful prognostic information for patients with clear cell RCC.     

miR-27a下调肾癌细胞FOXO1表达并促进其细胞增殖

目的：探讨microRNA-27a（miR-27a）在肾癌细胞中的作用及调控机制。方法：应用miR-27a反义寡核苷酸（ASO）在体外转染786-O和Caki-1细胞;qRT-PCR法检测miR-27a及FOXO1 mRNA的表达情况,Western blot检测FOXO1蛋白的表达水平;CCK8检测miR-27a ASO对细胞增殖的影响。结果：786-O和Caki-1细胞中miR-27a表达高于HK2正常肾小管上皮细胞（P〈0.05）;利用miR-27a ASO抑制786-O和Caki-1细胞miR-27a表达后,发现两个细胞株FOXO1 mRNA和蛋白表达的升高及增殖能力的降低（P〈0.05）。结论：miR-27a可能通过调控FOXO1表达在肾癌中起致癌作用。miR-27a ASO可抑制肾癌细胞的增殖,因此miR-27a有可能作为肾癌基因治疗的候选靶点。     

miR-27a下调肾癌细胞FOXO1表达并促进其细胞增殖

目的 探讨microRNA-27a(miR-27a)在肾癌细胞中的作用及调控机制.方法 应用miR-27a反义寡核苷酸(ASO)在体外转染786-O和Caki-1细胞;qRT-PCR法检测miR-27a及FOXO1 mRNA的表达情况,Western blot检测FOXO1蛋白的表达水平;CCK8检测miR-27a ASO对细胞增殖的影响.结果 786-O和Caki-1细胞中miR-27a表达高于HK2正常肾小管上皮细胞(P<0.05);利用miR-27a ASO抑制786-O和Caki-1细胞miR-27a表达后,发现两个细胞株FOXO1 mRNA和蛋白表达的升高及增殖能力的降低(P<0.05).结论 miR-27a 可能通过调控FOXO1表达在肾癌中起致癌作用.miR-27a ASO可抑制肾癌细胞的增殖,因此miR-27a有可能作为肾癌基因治疗的候选靶点.     

Akt activation in renal cell carcinoma: contribution of a decreased PTEN expression and the induction of apoptosis by an Akt inhibitor.

BACKGROUND: Akt has been implicated in the oncogenesis of human malignant tumors, because Akt regulates many key effector molecules involved in cell survival. PTEN (phosphatase and tensin homolog deleted on chromosome 10) negatively regulates Akt activation. MATERIALS AND METHODS: The expression of phosphorylated Akt (p-Akt), total Akt and PTEN was analyzed by Western blotting in 45 renal cell carcinoma (RCC) patients. The Bad and phosphorylated Bad (p-Bad) statuses were analyzed in 20 RCC patients. A phosphatidylinositol ether analog was used as an Akt inhibitor to treat four RCC cell lines, namely Caki-1, KU19-20, SW839 and Caki-2. RESULTS: The PTEN expression in RCC was observed to decrease and p-Akt expression to increase significantly in comparison with that in the corresponding normal kidney tissue. The PTEN expression inversely correlated with the p-Akt expression. These alterations were specific for clear cell type RCC, but not for papillary or chromophobe type RCC. Alterations in Bad phosphorylation were also specifically observed in clear cell type. The Akt inhibitor induced apoptosis in KU19-20 and Caki-2 cells with a high Akt activity. CONCLUSIONS: A decreased expression of PTEN may be an underlying mechanism for Akt activation. An Akt inhibitor may be a therapeutic option for a subset of RCC with an elevated Akt activity.     

Aberrant Methylation of the 1p36 Tumor Suppressor Gene RIZ1 in Renal Cell Carcinoma

Background: Retinoblastoma protein-interacting zinc finger gene 1(RIZ1) functions as a tumor suppressor.Hypermethylation-mediated RIZ1 silencing has been reported in several cancers, but not in renal cell carcinoma(RCC) yet. Materials and Methods: We examined the RIZ1 expression and methylation in a panel of RCC celllines and 50 primary tumors using semiquantitative/quantitative polymerase chain reaction (PCR), methylationspecific PCR, and bisulfite sequencing genomic. We also explored the relationship between methylation status ofRIZ1 and clinicopathological features in RCC patients. Results: RIZ1 expression was down-regulated or lost inOS-RC-2, 769-P, Caki-1, 786-O and A498 RCC cell lines. Restored expression of RIZ1 was detected after additionof 5-aza-2’-deoxycytidine with/without trichostatin A, suggesting that DNA methylation directly mediates itssilencing. The RIZ1 expression was significantly reduced in RCCs compared to adjacent non-malignant renalsamples (P<0.001). Aberrant methylation was detected in 15 of 50 (30%) RCCs and in 2 of 28 (7%) adjacent nonmalignantrenal samples (P=0.02). No statistically significant correlation between methylated and unmethylatedcases with regard to age, gender, pathological stage and grade was observed. Conclusions: RIZ1 expression isdown-regulated in human RCC, and this down-regulation is associated with methylation. RIZ1 methylation mayplay a role in renal carcinogenesis.     

Molecular genetics and immunohistochemistry characterization of uncommon and recently described renal cell carcinomas

Renal cell carcinoma (RCC) compromises multiple types and has been emerging dramatically over the recent several decades. Advances and consensus have been achieved targeting common RCCs, such as clear cell carcinoma, papillary RCC and chromophobe RCC. Nevertheless, little is known on the characteristics of several newly-identified RCCs, including clear cell (tubulo) papillary RCC, Xp11 translocation RCC, t(6;11) RCC, succinate dehydrogenase (SDH)-deficient RCC, acquired cystic disease-associated RCC, hereditary leiomyomatosis RCC syndrome-associated RCC, ALK translocation RCC, thyroid-like follicular RCC, tubulocystic RCC and hybrid oncocytic/chromophobe tumors (HOCT). In current review, we will collect available literature of these newly-described RCCs, analyze their clinical pathologic characteristics, discuss their morphologic and immunohistologic features, and finally summarize their molecular and genetic evidences. We expect this review would be beneficial for the understanding of RCCs, and eventually promote clinical management strategies.     

反义寡核苷酸沉默乙酰肝素酶对食管鳞癌细胞株TE-13侵袭能力的影响

背景与目的:乙酰肝素酶(heparanase,Hpa)为降解硫酸乙酰肝素多糖的内糖苷酶,在多种恶性肿瘤的侵袭转移中发挥重要作用。本研究旨在探讨Hpa在食管鳞癌细胞株TE-13中的表达和转染Hpa反义寡核苷酸(antisenseoligodeoxynucleotide,ASODN)对TE-13细胞的影响。方法:脂质体法转染人工合成的HpaASODN片段,应用RT-PCR、Westernblot和免疫细胞化学方法检测转染前后Hpa基因和蛋白表达的变化,Matrigel侵袭实验观察转染ASODN后TE-13细胞侵袭行为的改变。结果:在TE-13细胞中,RT-PCR扩增得到大小为585bp的Hpa基因条带,Westernblot检测到50ku大小的Hpa蛋白,免疫细胞化学染色表明Hpa主要定位于胞浆和胞膜。转染不同浓度HpaASODN后,RT-PCR、Westernblot和细胞免疫染色均证实TE-13细胞Hpa基因和蛋白表达下调,且随HpaASODN的浓度增高,基因和蛋白表达量逐渐降低(P<0.05),不同浓度HpaASODN组间有显著性差异(P<0.05)。Matrigel侵袭实验中,转染不同浓度HpaASODN后,侵袭至下室面的TE-13细胞数均下降(P<0.05)。随HpaASODN浓度的增高,侵袭至下室面的TE-13细胞个数逐渐减少(P<0.05),不同浓度HpaASODN组间有显著性差异(P<0.05)。结论:TE-13细胞存在Hpa基因的表达。HpaASODN能显著降低Hpa基因表达量,并且使TE-13细胞侵袭力明显下降。     

Inactivation of BHD in sporadic renal tumors

Studies of families with Birt-Hogg-Dubé syndrome (BHD) have recently revealed protein-truncating mutations in the BHD gene, leading to tumorigenesis of the skin and of different cell types of kidney. To additionally evaluate the role of BHD in kidney tumorigenesis, we studied 39 sporadic renal tumors of different cell types: 7 renal oncocytomas, 9 chromophobe renal cell carcinomas (RCCs), 11 papillary RCCs, and 12 clear cell RCCs. We screened for BHD mutations and identified a novel somatic mutation in exon 13: c.1939_1966delinsT in a papillary RCC. We performed loss of heterozygosity (LOH) analysis on 28 matched normal/tumor sets, of which 10 of 28 (36%) demonstrated LOH: 2 of 6 (33%) chromophobe RCCs, 5 of 6 (83%) papillary RCCs, 3 of 12 (25%) clear cell RCCs, but 0 of 4 renal oncocytomas. BHD promoter methylation status was examined by a methylation-specific PCR assay of all of the tumors. Methylation was detected in 11 of 39 (28%) sporadic renal tumors: 2 of 7 (29%) renal oncocytomas, 1 of 9 (11%) chromophobe RCCs, 4 of 11 (36%) papillary RCCs, and 4 of 12 (33%) clear cell RCCs. Five tumors with methylation also exhibited LOH. Mutation and methylation were absent in 9 kidney cancer cell lines. Our results showed that somatic BHD mutations are rare in sporadic renal tumors. The alternatives, LOH and BHD promoter methylation, are the two possible inactivating mechanisms involved. In conclusion, unlike other hereditary kidney cancer-related genes (i.e., VHL and MET), which are cell type-specific, BHD is involved in the entire spectrum of histological types of renal tumors, suggesting its major role in kidney cancer tumorigenesis.     

S100A1 and KIT gene expressions in common subtypes of renal tumours.

AIM: The aim of this study is to evaluate the S100A1 and KIT as gene markers for the differentiation of common subtypes of renal tumours. METHODS: Fifty-five tissue samples (15 clear cell RCCs, 15 papillary RCCs, 7 chromophobe RCCs, 8 oncocytomas and 10 normal renal tissues) were studied The gene expressions of S100A1 and KIT were analysed by one-step RT-PCR by using the specific primers. RESULTS: S100A1 was expressed in 2/15 clear cell RCCs, 11/15 papillary RCCs, 7/8 oncocytomas and in 0/7 chromophobe RCCs. KIT gene was expressed in 6/7 chromophobe RCCs and 7/8 oncocytomas while 0/15 clear cell RCCs and 1/15 papillary RCCs expressed kit gene. Normal tissue expressed neither S100A1 nor KIT gene. CONCLUSION: S100A1 and KIT can be used as gene markers for the differentiation of common subtypes of renal tumours.     

Transforming growth factor beta1 is a target for the von Hippel-Lindau tumor suppressor and a critical growth factor for clear cell renal carcinoma

The von Hippel-Lindau (VHL) tumor suppressor gene is mutated in patients with VHL disease and in the majority of patients with sporadic clear cell renal carcinoma (RCC). Overexpression of transforming growth factor (TGF) beta1 has been observed in patients with several cancers, including RCCs, with serum and urine levels correlating inversely with prognosis. We have demonstrated that the VHL tumor suppressor gene product represses TGF-beta1 mRNA and protein levels (approximately 3-4-fold) in 786-O RCC cells by decreasing the TGF-beta1 mRNA half-life. Exogenously added TGF-beta1 did not suppress the growth of 786-O cells in vitro, nor did the addition of neutralizing antibody (Ab) against TGF-beta have any effect. Indeed, 786-O cells were found to express no TGF-beta type II receptor protein, thus allowing them to escape from the negative growth control of TGF-beta1. In contrast to the in vitro data, neutralizing Ab to TGF-beta inhibited tumorigenesis and, in some cases, regressed established 786-O tumors in athymic mice. Immunohistochemistry for von Willebrand's factor revealed a 3-4-fold lower tumor microvessel count in the mice treated with TGF-beta Ab compared to controls, suggesting that the Ab was inhibiting angiogenesis. Our findings indicate that TGF-beta1 is a novel target for the VHL tumor suppressor and that antagonizing its paracrine action may provide novel avenues for treatment of RCCs as well as other tumors that secrete TGF-beta1.     

姜黄素诱导激活FOXO3a促进肾透明细胞癌细胞的增殖抑制和细胞凋亡

目的:研究姜黄素(curcumin)对人肾透明细胞癌（clear-cell renal cell carcinoma,ccRCC）细胞的增殖抑制和诱导凋亡作用,及叉头框蛋白O3a（Forkhead box protein O3a,FOXO3a）在姜黄素抗肿瘤效应中发挥的关键作用。方法:MTT法用于检测姜黄素对ccRCC细胞活力的抑制作用;Annexin V/PI双染实验检测姜黄素对ccRCC细胞的诱导凋亡作用;免疫印迹法（Western blot,WB）检测姜黄素对FOXO3a、p-FOXO3a及下游BIM表达的影响,和凋亡蛋白caspase 3的激活情况。实时荧光定量PCR技术（real-time quantitative PCR,RT-qPCR）检测FOXO3a转录水平。小干扰RNA（small interfering RNA,siRNA）技术用于沉默ccRCC细胞系中FOXO3a的表达。结果:通过对6种ccRCC细胞系（ACHN、786-O、769-P、A-498、Caki-1及Caki-2）FOXO3a蛋白基础表达水平进行检测,选取FOXO3a表达较高的786-O细胞系为研究对象。0~160 μmol/L姜黄素处理786-O细胞24 h和48 h后,呈时间和浓度依赖性对细胞活力具有显著抑制作用;786-O细胞在0~80 μmol/L姜黄素处理24 h后,明显促进细胞凋亡水平,且伴随着凋亡相关蛋白caspase 3的激活。786-O细胞中,姜黄素抑制p-FOXO3a,促进FOXO3a活化,并上调下游BCL-2家族促凋亡蛋白BIM表达水平。在siRNA沉默FOXO3a蛋白表达后,姜黄素对786-O细胞的生长抑制和诱导凋亡作用被抑制。结论:姜黄素通过诱导激活FOXO3a,在ccRCC细胞上发挥生长抑制和诱导凋亡的抗肿瘤作用。     

siRNA干扰FLOT2基因表达对肾细胞癌细胞增殖的影响

目的:探讨FLOT2在肾细胞癌细胞株中的表达,并观察小干扰RNA沉默FLOT2基因对肾细胞癌786-O细胞增殖能力的影响。方法:将化学合成的FLOT2的小干扰siRNA用脂质体 Lipofectamine2000转染至肾细胞癌786-O细胞;分别用RT-PCR、Western blot方法检测细胞转染前后FLOT2以及细胞增殖相关因子CCND1的表达。CCK-8与克隆形成实验检测其增殖情况。结果:转染FLOT2-siRNA的肾细胞癌786-O细胞,RT-PCR、Western blot检测显示FLOT2在基因及蛋白水平明显下调（P<0.05）;与对照组比较786-O细胞增殖能力明显下降（P<0.05）,细胞增殖相关因子CCND1明显下调（P<0.05）。结论:FLOT2在肾细胞癌细胞系中高表达,采用特异性FLOT2-siRNA 能够显著降低FLOT2和CCND1表达。干扰FLOT2表达能显著抑制786-O细胞的增殖,FLOT2基因可能参与了肾细胞癌的生物学行为。