Expression of growth-related genes during tumor progression in v-raf-transformed rat liver epithelial cells.

Clonal cell lines were derived from rat liver epithelial cells following their transformation with either v-raf or v-raf/v-myc. Cells transformed with v-raf alone showed reduced tumor incidence and tumor growth rates when implanted into nude mice, compared to cells also expressing the v-myc oncogene. A series of additional clones isolated from a tumor obtained following inoculation of an athymic nude mouse with the v-raf-transformed rat liver epithelial cells displayed an intermediate range of tumor aggressiveness. These findings indicate that unknown genotypic and/or phenotypic changes occur during tumor formation in vivo, which are required in addition to raf activation for complete expression of the malignant phenotype. This in vitro model of tumor progression was used to examine alterations in the expression of genes related to the growth control of liver epithelial cells, which may be involved in the malignant conversion of the preneoplastic cells. A close association was observed between the increased level of expression of the transforming growth factors alpha and beta 1, the decreased expression of extracellular matrix proteins fibronectin and collagen I, and the tumor aggressiveness (latency/growth rate), suggesting a causal role for these factors in the progression of v-raf-transformed rat liver epithelial cells to the fully malignant phenotype.     

Prediction of desmoid tumor progression using miRNA expression profiling

Desmoid tumor is a rare connective tissue tumor with locoregional aggressiveness but unpredictable behavior. The miRNA profile was ascertained for 26 patients included in the Desminib phase II trial and an independent validation cohort of 15 patients. Predictive and prognostic supervised analysis on the Desminib cohort failed to identify miRNAs differentially expressed between progressive and non‐progressive patients under imatinib treatment or between progressive and non‐progressive patients after discontinuation of imatinib. However, an unsupervised hierarchical clustering of the Desminib cohort identified two groups (A and B) of 13 patients each, where only the number of previous lines of treatment before inclusion in the study differed significantly between the two groups. Time to progression after discontinuation of imatinib was longer in group B than in group A. Fifteen miRNAs were highly statistically differentially expressed between groups A and B, targeting more than 3000 genes, including AGO1, BCL2, CDK6, SMAD4, PTEN, CCND1, VEGFA, and RB1. These results were confirmed in the independent validation cohort: hierarchical clustering of these 15 miRNAs identified two groups, in which time to recurrence was statistically different (28.8 months vs 68.8 months). These results provide the first indication of the prognostic value of miRNA expression profiling with a possible direct impact on patient management. A more precise miRNA signature must now be determined to select patients who would not benefit from surgical resection of their tumor and who ought to be monitored without treatment.     

Gene expression profiling of the tumor microenvironment during breast cancer progression

Introduction  

The importance of the tumor microenvironment in breast cancer has been increasingly recognized. Critical molecular changes in the tumor stroma accompanying cancer progression, however, remain largely unknown. We conducted a comparative analysis of global gene expression changes in the stromal and epithelial compartments during breast cancer progression from normal to preinvasive to invasive ductal carcinoma.     

Gene expression profiling of tumour epithelial and stromal compartments during breast cancer progression

The progression of ductal carcinoma in situ (DCIS) to invasive ductal carcinoma (IDC) marks a critical step in the evolution of breast cancer. There is some evidence to suggest that dynamic interactions between the neoplastic cells and the tumour microenvironment play an important role. Using the whole-genome cDNA-mediated annealing, selection, extension and ligation assay (WG-DASL, Illumina), we performed gene expression profiling on 87 formalin-fixed paraffin-embedded (FFPE) samples from 17 patients consisting of matched IDC, DCIS and three types of stroma: IDC-S (<3 mm from IDC), DCIS-S (<3 mm from DCIS) and breast cancer associated-normal stroma (BC-NS; >10 mm from IDC or DCIS). Differential gene expression analysis was validated by quantitative real time-PCR, immunohistochemistry and immunofluorescence. The expression of several genes was down-regulated in stroma from cancer patients relative to normal stroma from reduction mammoplasties. In contrast, neoplastic epithelium underwent more gene expression changes during progression, including down regulation of SFRP1. In particular, we observed that molecules related to extracellular matrix (ECM) remodelling (e.g. COL11A1, COL5A2 and MMP13) were differentially expressed between DCIS and IDC. COL11A1 was overexpressed in IDC relative to DCIS and was expressed by both the epithelial and stromal compartments but was enriched in invading neoplastic epithelial cells. The contributions of both the epithelial and stromal compartments to the clinically important scenario of progression from DCIS to IDC. Gene expression profiles, we identified differential expression of genes related to ECM remodelling, and specifically the elevated expression of genes such as COL11A1, COL5A2 and MMP13 in epithelial cells of IDC. We propose that these expression changes could be involved in facilitating the transition from in situ disease to invasive cancer and may thus mark a critical point in disease development.     

Role of the polarity determinant crumbs in suppressing mammalian epithelial tumor progression

Most tumors are epithelial-derived, and although disruption of polarity and aberrant cellular junction formation is a poor prognosticator in human cancer, the role of polarity determinants in oncogenesis is poorly understood. Using in vivo selection, we identified a mammalian orthologue of the Drosophila polarity regulator crumbs as a gene whose loss of expression promotes tumor progression. Immortal baby mouse kidney epithelial cells selected in vivo to acquire tumorigenicity displayed dramatic repression of crumbs3 (crb3) expression associated with disruption of tight junction formation, apicobasal polarity, and contact-inhibited growth. Restoration of crb3 expression restored junctions, polarity, and contact inhibition while suppressing migration and metastasis. These findings suggest a role for mammalian polarity determinants in suppressing tumorigenesis that may be analogous to the well-studied polarity tumor suppressor mechanisms in Drosophila.     

Role of epidermal-growth-factor receptor in tumor progression in transformed human mammary epithelial cells

The presence of epidermal-growth-factor receptors (EGFR) and of its ligands (TGFα and amphiregulin) in breast-cancer tissues suggests that they play a paracrine/autocrine role in tumor growth or progression. This hypothesis was tested on 3 cell lines, S2T2, NS2T2A and NS2T2A1. These epithelial cells are derived from a normal human breast-epithelial-cell culture transformed by SV40-T Ag, are of the same clonal origin, have respectively increasing levels of EGFR, TGFα, amphiregulin and of thymidine-kinase activity associated with increasing tumorigenic potential in nude mice (tumor intake and tumor volume). The monoclonal antibody MAb 425, which blocks ligands interaction with EGFR, reduced by more than 90% anchorage-independent growth of the most tumorigenic cells, NS2T2A1. Another anti-EGFR MAb, 528, reduced to 25% of controls the mean tumor mass after NS2T2A1 grafting in mice. Anti-sense RNA expression of EGFR in these cells confirmed the importance of this receptor in tumor progression, since it reduced significantly the tumor volume and tumor weight of NS2T2A1 cells to 16% of those in mock-transfected control cells. Int. J. Cancer 78:112–119, 1998.© 1998 Wiley-Liss, Inc.     

人成纤维细胞生长因子类似表达基因和成纤维细胞生长因子2在上皮性卵巢肿瘤组织中的表达

目的 探讨人成纤维细胞生长因子类似表达基因(hSef)和成纤维细胞生长因子2(FGF-2)在上皮性卵巢肿瘤组织中的表达及二者的关系.方法 采用免疫组化SP法检测31例卵巢恶性上皮性肿瘤(卵巢癌组)、18例卵巢良性上皮性肿瘤(良性组)和10例正常卵巢组织(正常组)中hSef和FGF-2蛋白的表达.采用逆转录聚合酶链反应(RT-PCR)检测卵巢癌组、良性组和正常组各24例组织中hSef和FGF-2 mRNA的表达水平.结果 与良性组、正常组相比,卵巢癌组hSef蛋白呈低表达(P＜0.001),而FGF-2蛋白呈高表达(P=0.002).hSef蛋白与FGF-2蛋白的表达呈负相关(rs=-0.324,P=0.012).hSefmRNA在正常组、良性组、卵巢癌组的表达呈下降趋势,而FGF-2mRNA表达呈增高趋势(P ＜0.001).hSef mRNA和FGF-2 mRNA的表达呈负相关(正常组rs=-0.910,P＜0.001;良性组rs=-0.859,P＜0.001;卵巢癌组rs=-0.888,P＜0.001).结论 在卵巢癌组织中,hSef表达下降,FGF-2表达增强.hSef的低表达减弱了FGF-2对细胞的增殖作用,促进了卵巢肿瘤的发生与发展.     

间叶上皮表型转化在肿瘤发生及演进中的作用

间叶上皮表型转化是指“间叶”向“上皮”细胞表型的可逆性转化,而非不同组织来源细胞间的转变.体内外实验证明,间叶上皮表型转化在恶性肿瘤侵袭和转移中发挥重要作用,现本文就其发展过程、研究现状进行综述.     

Expression of axl in lung adenocarcinoma and correlation with tumor progression

We used the Transwell system to select highly invasive cell lines from minimally invasive parent cells, and we compared gene expression in paired cell lines with high and low invasive potentials. Axl was relatively overexpressed in the highly invasive cell lines when compared with their minimally invasive counterparts. However, there is only limited information about the role of Axl in cancer invasion. The biologic function of Axl in tumor invasion was investigated by overexpression of full-length Axl in minimally invasive cells and by siRNA knockdown of Axl expression in highly invasive cells. Overexpression of Axl in minimally invasive cells increased their invasiveness. siRNA reduced cell invasiveness as Axl was downregulated in highly invasive cells. We further investigated the protein expression of Axl by immunohistochemistry and its correlation with clinicopathologic features. Data from a study of 58 patient specimens showed that Axl immunoreactivity was statistically significant with respect to lymph node status (P < .0001) and the patient's clinical stage (P < .0001). Our results demonstrate that Axl protein kinase seems to play an important role in the invasion and progression of lung cancer.     

Nuclear-mitochondrial genomic profiling reveals a pattern of evolution in epithelial ovarian tumor stem cells

Analyses of genome orthologs in cancer on the background of tumor heterogeneity, coupled with the recent identification that the tumor propagating capacity resides within a very small fraction of cells (the tumor stem cells-TSCs), has not been achieved. Here, we describe a strategy to explore genetic drift in the mitochondrial genome accompanying varying stem cell dynamics in epithelial ovarian cancer. A major and novel outcome is the identification of a specific mutant mitochondrial DNA profile associated with the TSC lineage that is drastically different from the germ line profile. This profile, however, is often camouflaged in the primary tumor, and sometimes may not be detected even after metastases, questioning the validity of whole tumor profiling towards determining individual prognosis. Continuing mutagenesis in subsets with a mutant mitochondrial genome could result in transformation through a cooperative effect with nuclear genes - a representative example in our study is a tumor suppressor gene viz. cAMP responsive element binding binding protein. This specific profile could be a critical predisposing step undertaken by a normal stem cell to overcome a tightly regulated mutation rate and DNA repair in its evolution towards tumorigenesis. Our findings suggest that varying stem cell dynamics and mutagenesis define TSC progression that may clinically translate into increasing tumor aggression with serious implications for prognosis.     

Expression of P-cadherin in gastric carcinomas and its reduction in tumor progression

The expression of P-cadherin, one of the Ca²⁺-dependent cell-cell adhesion molecules, in human gastric carcinomas was examined by Northern blotting, Western blotting and immuno-histochemistry. P-cadherin mRNA was expressed in all the gastric carcinoma tissues examined, whereas no message was detected in non-neoplastic mucosa. By Western-blot analysis, P-cadherin protein was expressed in 83% and 29% of the well-differentiated and poorly differentiated gastric adenocarcinomas, respectively, the incidence being significantly different. Immunohistochemically, P-cadherin immunoreactivity was localized on the cell surface or the cell-to-cell borders of well-differentiated adenocarcinomas. P-cadherin was not detected in Borrmann's type-4 or scirrhous carcinomas where the tumor cells proliferate diffusely with productive fibrosis. The level of P-cadherin expression in stage-2 carcinomas was significantly higher than in stage-1 carcinomas. In the case of patients in stages 2 to 4, however, the level of P-cadherin expression decreased as the stage progressed, the difference between stages 2 and 3 and between stages 3 and 4 being significant. Our findings suggest that P-cadherin might play an important role in the development of well-differentiated gastric adenocarcinomas and the decreased expression of P-cadherin might be responsible for the infiltrative growth and progression of gastric carcinomas.     

Loss of a tumor suppressor function during neoplastic progression of epithelial cells in vitro

In vitro transformation of rat urothelial cells is a multi-step process. We have used cell fusion to analyse the role of recessive events during in vitro progression of an immortal urothelial cell line. Somatic cell hybrids were made between the transformed cell line RM2T and a series of immortal urothelial cell lines, including the progenitor line RM2AD, from which RM2T was isolated. The ability to produce colonies in soft agar (anchorage independence) was used as an in vitro marker of transformation, and a series of 10 hybrid clones and 4 mass populations of hybrids were assessed for suppression of this phenotype. Hybrids between early-passage (less than passage 35, anchorage-dependent) RM2AD cells and late-passage (greater than passage 35, anchorage-independent) RM2T cells, showed suppression of anchorage independence when tested early after fusion (4/4 mass populations, 7/10 clones). This indicates that in vitro progression of this cell line is associated with loss of a function which can suppress growth in soft agar. Fusions between anchorage-independent RM2T cells and a series of other anchorage-dependent immortal urothelial cell lines generated hybrids which showed no suppression of anchorage independence, indicating that these anchorage-dependent cells have lost the suppressor function identified in RM2AD. Our results indicate that loss of a suppressor function can contribute to urothelial transformation in vitro and that clonal populations of immortal cells, at apparently the same stage of transformation, differ in their ability to suppress anchorage independence of the cell line RM2T. These differences provide the basis for suppressor-gene cloning experiments based on gene transfer.     

Transcriptional profiling of circulating tumor cells: quantification and cancer progression (Review)

Circulating tumor cells in peripheral blood have been demonstrated to reflect the biological characteristics of tumors including the potential for metastasis development and tumor recurrence. A number of mRNA markers may feasibly enable the detection of circulating tumor cells from virtually all patients with different cancer types. Of clinical relevance, quantification of circulating tumor cell mRNAs in cancer patients may prove valuable for monitoring disease progression and patients' response to treatment, and assessing the risk for metastasis or recurrence. With prognostic implications, the quantities of mRNA markers in blood could indicate the stage of cancer progression and the need for more intensive therapeutic intervention to better the outcome of cancer patients.     

Id2在上皮性卵巢肿瘤中的表达及意义

目的 探讨分化抑制因子(Id2)在上皮性卵巢肿瘤中的表达及其与雌激素受体(ER)、孕激素受体(PR)的相关性.方法 采用免疫组织化学SP法检测76例上皮性卵巢癌、30例卵巢交界性肿瘤和15例良性上皮性肿瘤中Id2的表达情况,分析Id2表达与上皮性卵巢癌临床病理特征的关系以及与ER、PR表达的相关性.结果 在卵巢癌、交界...     

人PTPRK基因在上皮性卵巢肿瘤中的表达及其意义

目的探讨受体型蛋白酪氨酸磷酸酶(PTPRK)基因在良性、交界性和恶性上皮性卵巢肿瘤及正常卵巢上皮组织中的表达规律及其与卵巢癌的关系.方法应用免疫组化间接法检测50例卵巢癌、13例良性上皮性卵巢肿瘤、14例交界性上皮性卵巢肿瘤及10例正常卵巢上皮组织中PTPRK基因的表达,采用Kaplan-Meier生存分析比较卵巢癌患者PTPRK蛋白表达与五年生存率的关系.结果(1)良性、交界性上皮性卵巢肿瘤和卵巢癌组中,PTPRK基因的阳性表达率分别为53.9%、57.1%、18.0%,显著低于正常卵巢上皮组的表达率100%(P均＜0.001).卵巢癌组中PTPRK基因的阳性表达率显著低于良性上皮性卵巢肿瘤组(P＜0.001)和交界性上皮性卵巢肿瘤组(P＜0.01).(2)卵巢癌高分化组中PTPRK基因的表达率为62.5%,显著高于中分化组(18.8%)和低分化组(6.3%)(P＜0.01).卵巢癌淋巴结无转移组PTPRK基因的表达率为27.3%,显著高于无阳性表达的淋巴结有转移组(P＜0.05).(3)PTPRK基因表达阳性组与表达阴性组的5年生存率分别为66.7%、46.7%,两组比较,差异无显著性(P＞0.05).结论PTPRK基因表达缺失发生在上皮性卵巢肿瘤组织中,肿瘤分化程度越低或者淋巴结已有转移则该基因表达缺失越明显.PTPRK基因可能是一种肿瘤抑制基因,其不同程度的表达缺失与上皮性卵巢肿瘤的发生和发展有关.     

促红细胞生成受体在上皮性卵巢肿瘤中的表达及其意义

目的了解促红细胞生成受体(EpoR)在卵巢良性、交界性、恶性上皮性肿瘤组织中的表达,探讨其与上皮性卵巢癌肿瘤发生发展的关系。方法用免疫组化SP法对51例卵巢癌组织、25例交界性上皮性卵巢肿瘤、31例良性上皮性卵巢肿瘤组织中EpoR的表达情况进行了检测。结果EpoR在恶性及交界性上皮性卵巢肿瘤中的强阳性表达率分别为67%、48%,明显高于良性肿瘤组的32%(P<0.05)。在卵巢癌中EpoR的表达与卵巢癌的临床分期有关,Ⅲ~Ⅳ期卵巢癌强阳性表达率73%,明显高于Ⅰ~Ⅱ期的56%(P<0.05),而与细胞分化程度无明显关联。但有淋巴结转移的病例强阳性表达率76%,明显高于无淋巴结的58%。结论EpoR的表达与上皮性卵巢肿瘤的发生发展关系密切。