Coordinate regulation of cyclooxygenase-2 and TGF-beta1 in replication error-positive colon cancer and azoxymethane-induced rat colonic tumors

Evidence is accumulating which indicates that cyclooxygenase-2 (COX-2) is involved in the pathogenesis of colorectal cancer. We evaluated the expression of COX-2 in replication error-positive (RER) colon cancers, colon cancers metastatic to liver and azoxymethane (AOM)-induced rat colonic tumors. Immunohistochemistry showed that COX-2 was low to undetectable in normal human mucosa, but abundant in the RER adenocarcinomas we examined. COX-2 immunoreactivity in metastatic colon cancers was less abundant, but clearly detectable. In the colon of AOM-treated rats, COX-2 protein was not detectable in normal mucosa, but present in most of the epithelial cells comprising the tumors. The TGF-beta1 staining pattern in these human and rat tumors was similar to that observed for COX-2. The role of TGF-beta in RER adenocarcinomas is complex because of the increased mutation rate of TGF-beta type II receptors. Northern analysis showed abundant TGF-beta1 mRNA in AOM-induced tumors, but not in paired mucosa. TGF-beta1 induced the expression of COX-2 mRNA and protein in intestinal epithelial cells (IEC-6). Chronic TGF-beta1 treatment caused a TGF-beta-dependent overexpression of COX-2 in rat intestinal epithelial cells (RIE-1). TGF-beta1 may regulate COX-2 expression during the colonic adenoma to carcinoma sequence.     

大肠肿瘤cyclin D1、p21WAF1/CIP1、p53和增殖细胞核抗原的免疫组化研究

目的：探讨细胞周期调控因子表达在大肠肿瘤发生发展中的作用及其预后的影响。方法：彩免疫组化染色对１１３例大肠癌、１４例大肠腺瘤、１１例腺瘤癌变组织中ｃｙｃｌｉｎＤ１、ｐ＾２１＾ＷＡＦ１／ＣＩＰＩ、ｐ＾５３和ＰＣＮＡ进行了检测。结果：大肠癌组织ｃｙｃｌｉｎＤ１和ｐ＾５３阳性表达率分别为５４．８７％和５６．６４％,均显著高于正常大肠组织（Ｐ〈０．０５）。高分化腺癌ｐ＾２１蛋白阳性表达率６９．７０％,低分     

Studies on recurrent breast cancer--clinicopathological factors and p53, p21Cip1/Waf1 and cyclin D1 protein expression

Of patients radically operated on for breast cancer in our department, 46 patients who had recurrent breast cancer were clinicopathologically evaluated to clarify the prognostic factors of recurrent breast cancer. Furthermore, p53, p21 and cyclin D1 protein expression were studied immunohistochemically and their prognostic value was evaluated. The relapse-free interval was highly related to the survival rate after the recurrence. p53 overexpression was correlated with the progression of clinical stage and lymph node metastasis and negatively correlated with the expression of estrogen receptor. The p21 positive and p53 negative cases had a significantly better prognosis than the p21 negative and p53 positive cases. The combination of p53 and p21 protein expression seemed to have prognostic value in recurrent breast cancer.     

Chemically induced rat mammary tumor treated with tamoxifen showed decreased expression of cyclin D1, cyclin E, and p21

We studied the effects of tamoxifen (TAM) on the growth of 7,12-dimethylbenz(a)anthracene (DMBA)-induced rat mammary tumor and the expression of cyclin D1, cyclin E, p21^Cip1, and estrogen receptors (ER) by performing immunohistochemistry and Western blot analysis. When tumor size reached between 10 and 15 mm in the largest dimension, the rats were divided into a DMBA-control group and a DMBA-TAM group. The administration of TAM markedly decreased the tumor development and showed decreased expression of bromodeoxyuridine, cyclin D1, cyclin E, and p21^Cip1 when compared with those of the DMBA-control group; however, a few tumors showed progressive growth in spite of TAM treatment. These tumors had decreased expression of ER. This study suggests that TAM suppresses tumor development through the down-expression of cyclin D1 and cyclin E.     

骨肉瘤p21 ras蛋白、p21 wafl/cip1蛋白、PCNA与AgNOR的表达及其临床意义

目的探讨骨肉瘤组织中p21ras蛋白、p21wafl/cip1蛋白、PCNA与AgNOR的表达及其临床意义.方法应用免疫组化方法和组织化学方法检测45例骨肉瘤病人的骨肉瘤组织、20例骨软骨瘤病人的骨软骨瘤组织和20例正常骨组织中p21ras蛋白、p21wafl/cipl蛋白、PCNA与AgNOR的表达情况,对有关临床病理指标综合分析.结果45例骨肉瘤组织中p21ras蛋白、p21wafl/cipl蛋白和PCNA的阳性表达率分别为86.7%、13.3%和100%,AgNOR计数为9.63±2.47,阳性表达率与AgNOR计数均高于骨软骨瘤和正常骨组织;p21ras蛋白的表达与PCNA的表达存在平行关系;AgNOR计数与PCNA的表达呈正相关;四者的表达与骨肉瘤有关临床病理指标之间存在一定的关系.结论检测p21ras蛋白、p21waf1/cip1蛋白、PCNA与AgNOR为骨肉瘤恶性程度和预后的评估提供了重要的辅助参考指标.     

Involvement of protein kinase C beta-extracellular signal-regulating kinase 1/2/p38 mitogen-activated protein kinase-heat shock protein 27 activation in hepatocellular carcinoma cell motility and invasion

To understand the molecular mechanism that underlies the role of various prominent signal pathways in hepatocellular carcinoma (HCC) metastasis, a human signal transduction oligonucleotide microarray analysis was carried out in cultured HCC cell models with increasing spontaneous metastatic potential (MHCC97L, MHCC97H, and HCCLM6). The results revealed that the mitogen-activated protein kinase (MAPK) pathway is the prominently upregulated pathway in HCC metastasis. Further study showed that basal phosphorylated levels of extracellular signal-regulating kinase (ERK)(1/2) and p38 MAPK consecutively increased from MHCC97L to MHCC97H to HCCLM6 cells, but not c-Jun N-terminal kinase. The phosphorylation of ERK(1/2) and p38 MAPK was regulated by upregulated protein kinase C beta (PKC beta) in HCC cells through the integrated use of PKC beta RNA interference, the PKC beta specific inhibitor enzastaurin and a PKC activator phorbol-12-myristate-13-acetate. Heat shock protein 27 (HSP27) was also verified as a downstream common activated protein of PKC beta-ERK(1/2) and PKC beta-p38 MAPK. In vitro migration and invasion assay further showed that the depletion of PKC beta or inhibition of PKC beta activation effectively decreased HCC cell motility and invasion. Moreover, the motility and invasion of phorbol-12-myristate-13-acetate-stimulated PKC beta-mediated HCC cells was significantly negated by an ERK inhibitor, 1.4-diamino-2.3-dicyano-1.4-bis[2-aminophenylthio] butadiene, or a p38 MAPK inhibitor, 4-(4-Fluorophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyridyl)1H-imidazole. It also showed that HSP27 is critical in PKC beta-mediated HCC cell motility and invasion. Taken together, this study reveals the important role of this PKC beta-ERK(1/2)/p38MAPK-HSP27 pathway, which was verified for the first time, in modulating HCC cell motility and invasion.     

PKCeta associates with cyclin E/cdk2/p21 complex, phosphorylates p21 and inhibits cdk2 kinase in keratinocytes

PKC is activated on the cell membrane by phospholipids, thereby transducing signals to intracellular pathways. We provide here another function of PKC, namely, regulating cell cycle by interaction with the cyclin E/cdk2/p21 complex. Among the 10 isoforms of PKC, PKCeta is predominantly expressed in squamous cell epithelia and induces terminal differentiation of keratinocytes. PKCeta that is endogenously expressed or overexpressed was found to associate with the cyclin E/cdk2/p21 complex in keratinocytes of mice and humans. Requirement of a possible adaptor protein to the binding was suggested by the reconstitution of PKCeta and the cyclin E/cdk2/p21 complex which were prepared from human keratinocytes or Sf9 insect cells. Colocalization of PKCeta with cdk2 and cyclin E was observed in the cytoplasm, particularly in the perinuclear region. p21 was phosphorylated in the complex in a PKC-activator dependent manner. Association of PKCeta with cdk2 resulted in marked inhibition of cdk2-kinase activity when measured by phosphorylation of Rb. Dominant negative PKCeta associated with the cyclin E/cdk2/p21 complex, but caused a little inhibition of cdk2 kinase activity. Among the known regulatory mechanisms of cdk2 activity, dephosphorylation of Thr160 was demonstrated. Oncogene (2000) 19, 6334 - 6341.     

Serine-arginine protein kinase 1 overexpression is associated with tumorigenic imbalance in mitogen-activated protein kinase pathways in breast, colonic, and pancreatic carcinomas

Aberrant patterns of pre-mRNA processing are typical of human malignancies, yet the mechanisms responsible for these changes remain undefined. We have recently shown overexpression of a core splice regulatory protein, serine-arginine protein kinase 1 (SRPK1), in dysplastic and neoplastic pancreatic ductular cells. In the present study, we have established that SRPK1 levels are similarly up-regulated in breast and colonic tumors where its expression increases coordinately with tumor grade. Targeting SRPK1 for inhibition using small interfering RNA in breast and colonic tumor cell lines in vitro resulted in both increased apoptotic potential and enhanced cell killing after treatment with gemcitabine and cisplatin. Recent reports have described multifaceted interactions between the mitogen-activated protein kinase (MAPK) and AKT signaling networks and the splice regulatory machinery. Consequently, we have shown that targeted inhibition of SRPK1 in tumor cells results in reduced phosphorylation of MAPK3, MAPK1, and AKT. Alterations in the splice pattern and resulting expression of MAPK kinase are implicated in mediating the antitumoral effects resulting from SRPK1 down-regulation. The up-regulation of SRPK1 in multiple cancers and its ability to regulate multiple relevant signaling pathways provide support for developing agents to inhibit this kinase for possible broad application to treat epithelial cancers.     

p21~(WAF1)、cyclinD1和pRb在膀胱移行细胞癌中的表达及其意义

 目的　探讨 p2 1WAF1、细胞周期蛋白D1(cyclinD1)和 pRb在膀胱移行细胞癌 (BTCC)中的表达及相互关系和其意义。方法　应用免疫组织化学SP法检测 5 7例BTCC患者癌组织中 p2 1WAF1、CyclinD1和 pRb的蛋白表达。 结果　p2 1WAF1、cyclinD1和 pRb的阳性表达率分别为 36 .8%、4 9.1%和 4 5 .6 % ,p2 1WAF1随病理分级升高阳性率显著下降 ,cyclinD1和 pRb的表达与BTCC的病理分级、临床分期和有无转移均相关 ,p2 1WAF1与 pRb的表达呈负相关 ,cyclinD1和 pRb的表达呈正相关 ,而 p2 1WAF1与cyclinD1的表达无关。结论　p2 1WAF1/cyclinD1/ pRb通路异常与BTCC的发生发展密切相关 ,p2 1WAF1的改变可能为癌变的早期事件 ,联合检测 p2 1WAF1、cyclinD1和 pRb可较准确地评价BTCC的生物学特性 ,估计预后 ,指导治疗     

Inhibitor of cyclooxygenase-2 induces cell-cycle arrest in the epithelial cancer cell line via up-regulation of cyclin dependent kinase inhibitor p21

Cyclooxygenase-2 is the rate-limiting enzyme in synthesis of prostaglandins and other eicosanoids. Prior reports have shown that inhibition of cyclooxygenase-2 activity, either by selective inhibitors or by antisense oligonucleotide, results in suppression of growth of squamous cell carcinoma cell lines which express high cyclooxygenase-2 levels, such as NA, a cell line established from a squamous cell carcinoma of the tongue. To investigate the mechanisms by which cyclooxygenase-2 inhibitors suppressed growth of these cells, the effects of NS-398, the selective cyclooxygenase-2 inhibitor, on cell-cycle distribution were examined. NS-398 induced G0/G1 cell-cycle arrest in NA cells which expressed cyclooxygenase-2. G0/G1 arrest induced by NS-398 was accompanied by up-regulation of cyclin-dependent kinase inhibitor p21, but not by up-regulation of the other cyclin-dependent kinase inhibitors. Transfection with p21 antisense oligonucleotide inhibited cell-cycle arrest induced by NS-398. Accumulation in G0/G1 was also observed in NA cells transfected with cyclooxygenase-2 antisense oligonucleotide. On the other hand, NS-398-treated NA cells showed a loss of plasma membrane asymmetry, a marker of early events in apoptosis. However, NS-398 did not induce other morphological and biochemical changes related to apoptotic cell death. These results suggest that cyclooxygenase-2 inhibitor induces G0/G1 cell-cycle arrest in NA cells by up-regulation of p21. Our results also suggest that NS-398 is not sufficient to complete the whole process of apoptosis in NA cells, although it induces an early event in apoptosis.     

睾丸精原细胞瘤中p27kip1、p21ras、p16的表达及其临床意义

目的探讨p27kip1、p21ras、p16在精原细胞瘤中的表达及临床意义.方法采用免疫组化S-P法检测46例精原细胞瘤组织、10例正常睾丸组织p27kip1、p21ras、p16蛋白的表达情况.同时用PCR法检测27例精原细胞瘤组织p16和p21基因的缺失情况.结果 p27kip1在精原细胞瘤组织中的阳性表达率为48.9%(22/45),显著低于正常睾丸组织的90.0%(P<0.05),p27kip1蛋白在精原细胞瘤组织中的阳性表达与淋巴结和远处器官转移相关(P<0.05),与组织学分型无关;p21ras、p16蛋白在精原细胞瘤组织中的阳性表达率分别为42.2%(19/45)和60.0%(27/45),与正常睾丸组织比较,差异无显著性(P>0.05).p16、p21ras蛋白在精原细胞瘤组织中的表达与组织学类型及淋巴结转移无相关性(P>0.05).p21基因无纯合子缺失.p16基因纯合子缺失率为44.4%(12/27),其缺失率与精原细胞瘤的组织学类型、淋巴结和远处器官转移无关.p27kip1、p21ras及p16阳性表达率之间有相关性(P<0.05).结论 p27kip1蛋白的低表达或缺失可能与精原细胞瘤的发生、浸润转移有关,可作为估计精原细胞瘤预后的良好指标.p16基因的缺失和表达下降可能是精原细胞瘤发生的早期事件.     

Expression of bcl-2, bax,and bcl-XL proteins in azoxymethane-induced rat colonic adenocarcinomas

Using western blotting and immunochemical analysis, we investigated alterations in the expression of the apoptosis-related proteins bcl-2, bax, and bcl-X in colonic adenocarcinomas induced by subcutaneous injection of azoxymethane (AOM) (15 mg/kg body weight weekly for 2 wk) into male Sprague-Dawley rats. Expression of the apoptosis-repressor bcl-2 in the colonic tumors was significantly weaker (0.6-fold) than that in adjacent non-neoplastic mucosa. The expression of bax protein, an apoptosis accelerator, was significantly stronger (7.33-fold) in all the tumors than in the non-tumoral mucosa. bcl-X_L protein, which functions as a repressor of apoptosis, was significantly upregulated (3.23-fold) in all the tumors when compared with the non-neoplastic mucosa. There was no significant difference between the expression of these proteins in the non-neoplastic mucosa of the AOM-treated rats and in the normal mucosa of saline-treated control rats. As determined by immunohistochemical analysis, the tumor cells had more bax and bcl-X protein. These findings indicate that the regulation of the apoptosis-related proteins bcl-2, bax, and bcl-X_L was altered in the AOM-induced colonic neoplastic tissue. In terms of resistance to apoptosis, elevated levels bcl-X_L protein may have considerable meaning in this experimental model as well as in human colorectal cancer. Mol. Carcinog. 19:25–30, 1997. © 1997 Wiley-Liss, Inc.     

胃癌及癌前病变中p16、p21WAF1、CDK4、cyclin D1蛋白的表达及其意义

目的探讨胃癌及癌前病变中p16、p21WAF1、CDK4和cyclinD1蛋白的表达、相互关系及其意义。方法应用免疫组化SP法检测胃癌、不典型增生、慢性浅表性胃炎及正常胃组织中p16、p21WAF1、CDK4和cyclinD1蛋白的表达情况。结果胃癌中p16和p21WAF1蛋白表达率分别为52.7％、30.9％,显著低于慢性浅表性胃炎和不典型增生（P<0.01）,而CDK4和cyclinD1蛋白表达率分别为61.8％、47.3％,均明显高于正常胃组织和慢性浅表性胃炎,差异有显著性（P<0.01）,但胃癌和不典型增生组织中CDK4和cyclinD1蛋白表达率之间差异无显著性（P>0.05）。胃癌中p16与cyclinD1蛋白表达呈负相关关系（P<0.05）,而CDK4与cyclinD1呈正相关关系（P<0.01）。结论胃癌发生机制涉及p16、p21WAF1、CDK4和cyclinD1调节通路中多个基因的异常,且与胃癌Lauren分型、浸润深度、淋巴结转移有关。CDK4和cyclinD1蛋白高表达可能是胃癌发生过程中的早期分子事件。