Introducing the clusterin gene into human renal cell carcinoma cells enhances their metastatic potential

PURPOSE: We recently reported a protective role of clusterin expression against apoptosis induced by a wide variety of stimuli in several human cancer models. In the current study we tested the hypothesis that clusterin over expression confers a benefit for the metastasis of renal cell carcinoma through the inhibition of apoptosis induced by the various obstacles the cancer cells may confront after detachment from their primary origin. MATERIALS AND METHODS: We introduced clusterin complementary DNA into human renal cell carcinoma ACHN cells, which do not express detectable level of clusterin expression, and generated the clusterin over expressing cell line ACHN/CL and the control vector only transfected cell line ACHN/C. In vitro anti-cell death activity under anchorage independent conditions among ACHN sublines was examined by limiting dilution assay and cell survival assay in suspension. To investigate the in vivo effects of clusterin over expression on metastatic potentials each cell line was injected into the tail vein or renal subcapsule of nonobese diabetic, severe combined immunodeficient mice and the metastatic features in all abdominal and thoracic organs were evaluated. RESULTS: ACHN/CL showed significantly enhanced growth in limiting dilution cultures compared with ACHN/C. The analysis of cell survival in the floating assay also revealed that ACHN/CL had a powerful survival advantage in suspension compared with ACHN/C. Furthermore, ACHN/CL formed more than 5-fold as many metastatic nodules in the lung after intravenous injection than ACHN/C. Similarly more marked lung metastasis was observed after implanting ACHN/CL cells into the renal subcapsule than after implanting ACHN/C cells. In contrast, there were no significant differences among ACHN sublines in the growth rates in vitro and in vivo, cell motility or invasive ability. CONCLUSIONS: These findings suggest that, if clusterin is over expressed, it prolongs cell survival under unfavorable conditions in the metastatic process, resulting in the enhanced metastatic potential of renal cell carcinoma.     

In vivo description of dendritic cells in human renal cell carcinoma.

PURPOSE: Dendritic cells (DCs) are efficient and effective antigen-presenting cells that play a major role in initiating the primary immune response. They are the most potent stimulators of T-cell activation and would thus be expected to be of great importance in the antitumoral immune response. Although DC phenotype and function have been described under in vitro conditions, their in vivo characteristics are less well detailed. Human renal cell carcinoma (RCC) is an excellent model to explore tumor infiltrating dendritic cells (TiDCs) because of rare clinical spontaneous regressions and the association of high numbers of tumor infiltrating lymphocytes (TiLs), suggesting a strong immune response. MATERIALS AND METHODS: We determined the in situ phenotype of mature CD83+ TiDCs using monoclonal antibodies to known activation molecules (CD86 [B7.2], CD80 [B7.1], CD40, CD54, CD1a and HLA-DR). Seventeen primary RCCs, representing four distinct histologies, were evaluated using double-staining immunohistochemical techniques and light microscopy. RESULTS: CD83+ TiDCs were found in all tumors. Expression of CD40 correlated with expression of CD1a on CD83+ TiDCs. Expression of CD54 (ICAM-1) correlated with a lower expression of CD86 (B7.2) as well as a decrease in CD3+ and CD8+ TiLs. CONCLUSIONS: These data suggest a de novo lipid or sugar-based immunogenic antigen presentation by TiDCs. Also, the data support an impaired antigen-presenting capability for CD54+ TiDCs based on the decreased coexpression of CD86 (B7.2) and the decrease of associated CD8+ TiLs.     

Inhibition of bcl-2 enhances the efficacy of chemotherapy in renal cell carcinoma

OBJECTIVES: Renal cell cancer (RCC) is highly resistant to chemotherapy. Increased expression of the antiapoptotic gene bcl-2 in tumors is known to be associated with poor responses to systemic treatment of cancer. Down-regulation of bcl-2 expression using antisense oligonucleotides (asON) has been shown to increase chemosensitivity in clinical phase I-III studies with various cancers. However, no studies on the efficacy of this approach in RCC have been reported so far. This study aimed to evaluate whether bcl-2 asON could enhance efficacy of chemotherapy in human RCC. MATERIAL AND METHODS: Expression of bcl-2 mRNA and protein was analyzed in different RCC cell lines by RT-PCR and Western blot. Cells with high or low bcl-2 mRNA and protein expression were treated with different concentrations of bcl-2 asON in combination with cisplatin. AsON-induced down-regulation of bcl-2 mRNA and protein was documented by RT-PCR and Western blot. Treatment effects on cell viability were analyzed by colorimetric tetrazolium (MTT) assay. Immunohistochemical staining of M30-positive cells was performed for quantification of apoptotic cells. RESULTS: Transfection of high bcl-2 expressing cells with bcl-2 asON alone induced no reduction of cell viability at a concentration range from 100-1000 nM. In combination therapy, pretreatment with asON significantly enhanced MTT reduction after cisplatin treatment. IC50 concentrations of cisplatin were 1 microg/ml with and 2.7 microg/ml without prior incubation. The marked reduction of cell viability correlated with an 8-fold increase of apoptotic cells after combination treatment. Only a minor increase of cisplatin effectivity was noted after asON preincubation of cells with lower bcl-2 expression. CONCLUSIONS: The combination of cisplatin and bcl-2 antisense ON exerts significantly greater effects on cell viability and apoptosis than either agent used alone on human RCC cells. These data indicate that inhibition of bcl-2 expression may be an attractive therapeutic strategy in RCC tumors with high bcl-2 expression.     

蓝舌病毒HbC_3对人肾癌细胞的感染杀伤作用

目的 观察蓝舌病毒湖北株(BTV-HbC_3)对人肾癌ACHN细胞的感染特性,探讨其杀伤肾癌细胞作用及其机制.方法 BTV-HbC_3感染肾癌ACHN细胞,观察细胞病变效应及显微电镜变化,噻唑蓝(MTT)比色法检测细胞存活率,RNA凝胶电泳检测BTV-HbC_3在ACHN细胞内的增殖,DNA ladder法检测感染后凋亡并用流式细胞仪检测感染后细胞凋亡指数.结果 BTV-HbC_3感染细胞后有明显的细胞病变效应,细胞胞质内出现病毒颗粒,细胞肿胀破裂,1 MOI的BTV-HbC_3感染ACHN细胞24、36、48 h的存活率分别为68.14±5.13、57.14±2.68、42.21±5.63.RNA电泳出现L1-L3、M4-M6和S7-S10特征性病毒dsRNA,DNA ladder显示非特异凋亡表现,流式细胞仪检测1 MOI的BTV-HbC_3感染ACHN细胞24、36、48 h后可见低亚二倍体峰,比例分别为13.7%、18.5%和24.2%.结论 BTV-HbC_3能有效地杀伤人肾癌ACHN细胞.     

Tim-3 expression represents dysfunctional tumor infiltrating T cells in renal cell carcinoma

Purpose

Renal cell carcinoma (RCC) is the most common cancer of kidney. Evidences have shown that RCC is sensitive to various immunotherapies. Tim-3 plays a role in suppressing Th1-mediated immune responses. However, no study has yet examined the effect of Tim-3 on tumor infiltrating lymphocytes (TILs) in RCC.

Methods

We investigated the expression and function of Tim-3 on TIL CD4+ T cells and TIL CD8+ T cells from 30 RCC patients.

Results

Levels of Tim-3 were significantly increased on both TIL CD4+ T cells and TIL CD8+ T cells and were associated with higher stages of the cancer. Also, GATA-3 and interferon gamma (IFN-γ) were down-regulated, whereas T-bet was up-regulated in TIL Tim-3+ T cells, indicating that Tim-3 expression defined a population of dysfunctional TIL Th1/Tc1 cells. Mechanism analyses showed that TIL Tim-3-expressing CD8+ T cells exhibited impaired Stat5 and p38 signaling pathway. Blocking the Tim-3 pathway restored cell proliferation and increased IFN-γ production in TIL CD4+ and CD8+ T cells of RCC.

Conclusions

These results suggest that Tim-3 may be used as a novel target for increasing immune responses in RCC tumor microenvironment.

     

Prognostic significance of erythropoietin expression in human renal cell carcinoma

OBJECTIVES: To investigate, in a retrospective study, the expression of erythropoietin (Epo) in human renal cell carcinoma (RCC) and its correlation with overall survival, as Epo (an haematopoietic cytokine that regulates the production of red blood cells), with its receptor, was recently localized in non-haematopoietic tissues, e.g. liver, uterus, central nervous system, vascular endothelial cells and solid tumours. PATIENTS AND METHODS: We used data from 113 patients who had radical nephrectomy for RCC between 1990 and 2000, taking sections from formalin-fixed and paraffin wax-embedded tissue blocks. The association between Epo staining and the patients' characteristics was assessed by either chi-squared tests (for categorical variables) or two-sample independent t-tests (for continuous variables). RESULTS: Tissue from 37 patients (33%) was positive for cytoplasmic Epo expression; 76 (67%) samples were negative. Univariate hazard ratio analysis confirmed that those with positive Epo staining were more than twice as likely to die as those with negative staining (hazard ratio 2.34, 95% confidence interval 1.27-4.3). CONCLUSION: This study shows that the expression of Epo in RCC is adversely associated with overall survival. This is the first report of such an association, and might be explained by the loss of Von Hippel-Lindau protein function in clear cell RCC. The expression of Epo might have potential use in clinical trials when stratifying high-risk patients for adjuvant therapy after nephrectomy.     

Over expression of metallothionein predicts resistance of transitional cell carcinoma of bladder to intravesical mitomycin therapy

PURPOSE: Metallothionein, a low molecular weight intracellular protein, binds mitomycin with high affinity protecting the tumor DNA. We prospectively studied the relationship of metallothionein expression in bladder transitional cell carcinoma and resistance to intravesical mitomycin. MATERIALS AND METHODS: A series of 45 consecutive patients with superficial transitional cell carcinoma treated with intravesical mitomycin were studied. Resected tumor tissues were stained with metallothionein monoclonal antibody E9. Two pathologists scored staining intensity and distribution. All patients were followed with regular flexible cystoscopy. RESULTS: Median patient age was 73 years (range 44 to 89). Tumor grade was 1 to 3 in 6, 33 and 6 cases, respectively. In 20 patients (44.44%) tumor recurred after mitomycin therapy. Median cytoplasmic staining scores for recurrent and nonrecurrent tumors were 5 (range 0 to 61) and 0 (0 to 14), respectively. Median nuclear staining scores for recurrent and nonrecurrent tumors were 3 (range 0 to 56) and 0 (0 to 11), respectively. Median followup of patients without recurrence was 18 months (range 12 to 36). Nuclear and cytoplasmic staining scores were significantly higher in recurrent than in nonrecurrent tumors. There was no significant relationship of metallothionein expression with tumor grade. CONCLUSIONS: Over expression of metallothionein predicts the resistance of bladder transitional cell carcinoma to intravesical mitomycin therapy.     

肾癌表皮生长因子受体和增殖细胞核抗原表达的研究

采用免疫组化法对４０例肾癌组织中表皮生长因子受体（ＥＧＦＲ）及增殖细胞核抗原（ＰＣＮＡ）进行检测，取２０例远离癌组织的旁肾组织作为对照。发现肾癌组织ＧＥＦＲ阳性表达显著高于对照组，ＥＧＦＲ表达与肿瘤分级分期无相关性。肾癌组织的ＰＣＮＡ增殖指数随肿瘤分级的上升而增高。ＰＣＮＡ高表达组（增殖指数大于１０％）术后生存时间显著较ＰＣＮＡ低表达组（小于或等于１０％）短，强调指出那些临床低分期但ＰＣＮＡ高表达     

Strategies to overcome therapeutic resistance in renal cell carcinoma

Background

Renal cell cancer (RCC) is a prevalent and lethal disease. At time of diagnosis, most patients present with localized disease. For these patients, the standard of care includes nephrectomy with close monitoring thereafter. While many patients will be cured, 5-year recurrence rates range from 30% to 60%. Furthermore, nearly one-third of patients present with metastatic disease at time of diagnosis. Metastatic disease is rarely curable and typically lethal. Cytotoxic chemotherapy and radiation alone are incapable of controlling the disease. Extensive effort was expended in the development of cytokine therapies but response rates remain low. Newer agents targeting angiogenesis and mTOR signaling emerged in the 2000s and revolutionized patient care. While these agents improve progression free survival, the development of resistance is nearly universal. A new era of immunotherapy is now emerging, led by the checkpoint inhibitors. However, therapeutic resistance remains a complex issue that is likely to persist.

Differential expression of potassium ion channels in human renal cell carcinoma

Purpose  Ether-a-go-go (EAG) or EAG-related (ERG) voltage-gated potassium ion channels are involved in tumor generation and progression. Their over- and/or misexpression has been demonstrated in various tumors, and inhibition of these channels has suppressed proliferation of various cancer cells. We investigate and compare the pattern of expression of EAG and human ERG (HERG) channels in renal cell carcinoma and “normal” renal tissue. Method  Tissue samples, obtained at the time of radical nephrectomy from the tumor-bearing areas, and uninvolved renal tissue were preserved in 4% paraformaldehyde and cryosectioned at 20 μm. Immunohistochemical and Western blot analysis was performed on the tumor and uninvolved kidney parenchyma by incubating with polyclonal anti-HERG 1b (Alomone Lab, Israel), anti-EAG1, and anti-EAG2. Pattern of expression of EAG/HERG channels in normal renal tissue and carcinoma were noted and compared. Results  The study was performed on 16 radical and four partial nephrectomy specimens (n = 20). All tumors in the cohort were clear cell renal carcinoma. Normal renal tissue was found to exhibit heterogeneous cytoplasmic positivity for EAG1 and focal HERG immunoreactivity (IR) in the proximal (PCT) and distal convoluted tubules (DCT). EAG2 IR was absent in the normal renal tissue. Clear cell RCC demonstrated a loss of HERG expression while diffuse overexpression of EAG1 and EAG2 was noted. Western blot analysis corroborated the immunohistochemical observations. Conclusions  In our study both EAG1 and EAG2 potassium channels were overexpressed in clear cell renal cancer. In contrast to other adenocarcinomas, there is loss of HERG expression in clear cell RCC, which may possibly explain its chemoresistance. These ion channels may provide a potential for targeted therapy.     

Mechanisms and modulation of multidrug resistance in primary human renal cell carcinoma

Human renal cell carcinomas show a high degree of intrinsic multidrug resistance. In experimental cell lines, the membrane bound P-170 glycoprotein and the glutathione redox cycle seem to contribute to this phenomenon. P-170 may be inactivated by calcium antagonists; the glutathione redox cycle by buthionine sulfoximine. We studied the resistance patterns of 35 human renal cell carcinomas against vinblastine, doxorubicin and carboplatinum in a tetrazolium-based microculture assay. Concomitantly, P-170 expression was traced immunohistochemically using moab C219 and the glutathione content was determined enzymatically. Reversal of multidrug resistance was examined by applying the R-stereoisomer of verapamil and/or by addition of buthionine sulfoximine. A high degree of chemoresistance was seen in 27 tumors against vinblastine, in 30 tumors against doxorubicin and in 31 tumors against carboplatinum. Chemoresponse was found in eight, five or four cases respectively. P-170 was detected in 70% of highly vinblastine resistant and in 63% of highly doxorubicin resistant tumors, but in none of the less resistant cases. Resistance against carboplatinum and doxorubicin was significantly associated with elevated glutathione levels as compared to less resistant renal cell carcinomas. R-verapamil lead to a strong reversal of vinblastine resistance and to a distinct circumvention of doxorubicin resistance, but revealed no effect in carboplatinum resistance. Buthionine sulfoximine overcame carboplatinum resistance and modified doxorubicin resistance, but had no influence on vinblastine resistance. The combined application of R-verapamil and buthionine sulfoximine reversed doxorubicin resistance but did not act synergistically in vinblastine or carboplatinum resistance. Both mechanisms, P-170 and glutathione, occurred independently of each other and may well explain multidrug resistance of human renal cell carcinomas.