胸苷磷酸化酶在结直肠癌研究中的意义

研究发现胸苷磷酸化酶具有促进肿瘤血管新生和抗细胞凋亡作用,与肿瘤患者预后转归密切相关.同时,它也是5＇-脱氧氟脲苷等5-氟尿嘧啶前体药物的关键转化酶.笔者对胸苷磷酸化酶在结直肠癌组织中的表达、发挥的作用和5＇-脱氧氟脲苷在细胞内的激活、治疗等的研究进展进行综述.     

结直肠癌组织中巨噬细胞因子的分子生物学作用

巨噬细胞因子（macrophage cytokine,MCK）是由单核-巨噬细胞合成分泌的一类具有广泛生物学活性的小分子蛋白质,在体内的作用非常复杂,既可以参与机体的炎症反应、免疫应答、免疫调节,又有抗肿瘤和促进肿瘤生长的双重作用。近年来,发现MCK可以通过增加肿瘤组织中胸苷磷酸化酶（thymidine phosphorylase,dThdPase）的表达而使5＇-脱氧氟尿苷（商品名氟铁龙,5＇-DFUR）转化为5-氟尿嘧啶5-FU,起到细胞毒性作用。现将MCK在结直肠癌组织中的表达,和它在肿瘤的生长、浸润、转移、治疗中的重要作用进行综述。     

Prognostic value of tumor-associated macrophage count in human bladder cancer

BACKGROUND: We determined the tumor-associated macrophage (TAM) count to investigate its importance in predicting clinical outcome or prognosis in patients with bladder cancer. METHODS: The TAM count and microvessel count (MVC) were determined immunohistochemically in 63 patients with bladder cancer, including 40 superficial bladder cancers and 23 invasive bladder cancers. To examine the relationship between TAM count and clinical outcome or prognosis in bladder cancer, cystectomy rates, distant metastasis rates, vascular invasion rates and 5 year survival rates were compared between patients with low (< 67) and high (> or = 67) TAM counts. RESULTS: The TAM count in invasive bladder cancers (154.22+/-11.98) was significantly higher than in superficial bladder cancers (49.05+/-7.76; P<0.0001). The MVC in invasive bladder cancers (71.55+/-10.44) was also significantly higher than in superficial bladder cancers (47.02+/-5.57; P<0.05). There was a positive correlation between TAM count and MVC (r=0.30; P=0.02). Immunohistochemical staining using CD68/horseradish peroxidase monoclonal antibody showed more infiltrating cells in invasive than superficial bladder cancers. Patients with a high TAM count (> or =67) showed significantly higher rates of cystectomy, distant metastasis and vascular invasion than those with a lower TAM count (<67). The 5 year survival rate estimated using the Kaplan-Meier method was significantly lower in patients with a high TAM count than in those with a low TAM count (P<0.0001). CONCLUSIONS: Our results suggest that determination of TAM count in bladder cancer tissues is of value to predict the clinical outcome or prognosis and to select appropriate treatment strategies in patients with bladder cancer.     

The inhibitory effects of interferon gamma on the growth of bladder cancer cells.

The inhibitory effect of interferon-gamma on the growth of three human bladder cancer cell lines, RT4, RT112 and MGH-U1, representing tumour grades 1, 2 and 3 respectively, was studied. The effects of 10, 100 and 1000 Uml.-1 of interferon-gamma on cell numbers and thymidine incorporation were measured at 24 hour intervals up to a maximum of seven days. Morphological appearances were also studied. Each line was susceptible to the growth inhibitory effects of interferon-gamma and this was both dose and time dependent. The effects of interferon-gamma, on the RT4 and RT112 cells were apparent from 24 hours, and were both cytostatic and cytotoxic in nature, whereas the effects on MGH-U1 cells were seen from 48 hours onwards and were only cytostatic. Cytological changes occurred in all three cell lines, being most pronounced in RT112. The growth of bladder cancer cells was inhibited by interferon-gamma, and in this study high grade tumour cells were least sensitive.     

The liposome-incorporating cell wall skeleton of Mycobacterium bovis bacillus Calmette-Guéin can directly enhance the susceptibility of cancer cells to lymphokine-activated killer cells through up-regulation of natural-killer group 2, member D ligands

OBJECTIVE

? To conduct a preclinical evaluation of the ability of natural killer cells to cytolyze bladder cancer cells that were modified to show enhanced expression of natural‐killer group 2, member D (NKG2D) ligands by R8‐liposome‐bacillus Calmette‐Guéin (BCG)‐cell wall skeleton (CWS) treatment.

MATERIALS AND METHODS

? The T24 cells and RT‐112 cells were co‐cultured with R8‐liposome‐BCG‐CWS and BCG for 2, 4, or 6 h, and then the surface expression of NKG2D ligands was analyzed using TaqMan real‐time quantitative RT‐PCR. ? Peripheral blood mononuclear cells were obtained with a conventional preparation kit, and then lymphokine‐activated killer (LAK) cells were generated from these purified peripheral blood mononuclear cells via interleukin‐2 stimulation. ? The anti‐tumour effect of LAK cells against untreated and R8‐liposome‐BCG‐CWS co‐cultured with cells of the human bladder cancer cell lines T24 and RT‐112 was analyzed using the cytotoxic WST‐8 assay method at 4 h of culture at various effector/target (E : T) ratios.

RESULTS

? Major histocompatibility complex class I‐related chain B (MICB) expression was increased ≈1.5‐fold on T24 cells and RT‐112 cells with BCG. ? UL‐16‐binding protein (ULBP) 1 expression was also increased ≈1.5‐fold on T24 cells and RT‐112 cells with BCG. R8‐liposome‐BCG‐CWS increased the surface expression of MICB 2.2‐fold on T24 cells but did not increase it significantly on RT‐112 cells. ? ULBP1 expression was increased ≈2.2‐fold on RT‐112 cells, although no differences were observed between the expression of ULBP2 and 3 with R8‐liposome‐BCG‐CWS. ? T24 cells that were co‐cultured with R8‐liposome‐BCG‐CWS showed an ≈1.3‐fold increase in sensitivity to cytolysis by LAK cells at an E : T ratio of 4 and RT‐112 cells showed an ≈1.4‐fold increase at an E : T ratio of 2.

CONCLUSIONS

? In the present study, the induction of surface NKG2D ligands by R8‐liposome‐BCG‐CWS rendered cancer cells more susceptible to cytolysis by LAK cells. ? T24 cells and RT‐112 cells, even when cultured singly in the absence of immune cells, can directly respond to R8‐liposome‐BCG‐CWS. ? The results obtained in the present study may therefore indicate a novel adoptive immunotherapy against bladder cancers.     

Antineoplastic activity of honey in an experimental bladder cancer implantation model: In vivo and in vitro studies

OBJECTIVES: The antitumor effect of bee honey against bladder cancer was examined in vitro and in vivo. Methods: Three human bladder cancer cell lines (T24, 253J and RT4) and one murine bladder cancer cell line (MBT-2) were used in these experiments. In an in vitro study, the antitumor activity was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay, TdT-mediated dUTP-biotin nick end labeling (TUNEL) assay, 5-Bromodeoxyuridine (BrdU) labeling index and flowcytometry (FCM). In the in vivo study, cancer cells were implanted subcutaneously in the abdomens of mice, and the effects were assessed by the tumor growth. RESULTS: In vitro studies revealed significant inhibition of the proliferation of T24 and MBT-2 cell lines by 1-25% honey and of RT4 and 253J cell lines by 6-25% honey. BrdU labeling index was significantly lower. FCM showed lower S-phase fraction, as well as absence of aneuploidy compared with control cells. In the in vivo studies, intralesional injection of 6 and 12% honey as well as oral ingestion of honey significantly inhibited tumor growth. CONCLUSION: Bee honey is an effective agent for inhibiting the growth of T24, RT4, 253J and MBT-2 bladder cancer cell lines in vitro. It is also effective when administered intralesionally or orally in the MBT-2 bladder cancer implantation models. Our results are promising, and further research is needed to clarify the mechanisms of the antitumor activity of honey.     

Matrix metalloproteinases (MMPs) in bladder cancer: the induction of MMP9 by epidermal growth factor and its detection in urine

OBJECTIVES: To investigate the matrix metalloproteinases (MMPs) 2 and 9 in bladder cancer cell lines stimulated with epidermal growth factor (EGF), and to investigate the presence of gelatinases in the urine of patients with bladder tumours, in relation to the stage and grade of tumour and the EGF receptor (EGFR) status. PATIENTS, SUBJECTS AND METHODS: Conditioned media from cultured tumour cells were analysed by zymography. Urine samples from 28 patients with transitional cell carcinoma and 12 normal volunteers were also analysed. Western blotting was used to verify the bands of gelatinolytic activity. The EGFR status of the tumours was assessed by immunohistochemistry. RESULTS: MMP9 was induced by EGF in the RT112 but not the RT4 bladder tumour cell line, whereas MMP2 production was unaffected by EGF. Gelatin zymography of urine samples from patients with bladder tumours showed high levels of MMP activity, with 78% positive for MMP9 and 28% positive for MMP2. The total gelatinolytic and MMP9 activity were significantly higher in patients with high-stage invasive tumours than in those with superficial tumours (P < 0.05), and were higher than in normal controls. Gelatinolytic activity at 130 and 200 kDa in urine was identified as MMP9 and MMP2. There was no significant relationship of urinary MMP9 activity to EGFR status of the tumour. CONCLUSION: EGF induces MMP9 but not MMP2 in bladder cells. Analysis of urinary gelatinases is a useful noninvasive technique and both total gelatinase and MMP9 activity are associated with high stages of bladder tumours.     

氟伐他汀诱导人膀胱癌细胞凋亡抑制细胞增殖与迁移的研究

目的 研究羟甲戊二酸单酰辅酶A(HMG-CoA)还原酶抑制剂--氟伐他汀在体外对人膀胱癌T24细胞凋亡、增殖和迁移及侵袭能力的影响,并探讨相关分子机制.方法 MTT法检测氟伐他汀对T24细胞增殖的影响;流式细胞术(PI和Annexin V双染法)检测细胞凋亡率的变化;划痕愈合和Transwell试验检测氟伐他汀对肿瘤细胞迁移和侵袭能力的影响;Western blot检测Bax、Cleaved-caspase-3等蛋白的表达情况.结果 氟伐他汀在体外能显著抑制T24细胞的增殖,成明显浓度和时间依赖性;可以显著诱导肿瘤细胞凋亡;能显著抑制T24细胞的迁移和侵袭能力.结论 氟伐他汀能显著诱导T24细胞发生凋亡,抑制肿瘤细胞的增殖、迁移和侵袭能力.     

The phosphatidylinositol-3 kinase pathway regulates bladder cancer cell invasion

OBJECTIVES: To investigate the role of the phosphatidylinositol (PI)-3 kinase pathway in the invasion of bladder cancer cell lines, and to assess the activation of this pathway in primary human bladder tumours. MATERIALS AND METHODS: Human bladder cancer cells were treated with pathway specific inhibitors or were transfected with PI-3 kinase pathway components. The invasion of cultured bladder cancer cells was analysed by an invasion assay. Bladder cancer cells lines and primary human bladder tumours were analysed for pathway activation by western blotting. RESULTS: A specific inhibitor of PI-3 kinase enzyme activity, Ly294002, potently suppressed the invasive properties of three highly invasive bladder tumour cell lines. Restoration of the PTEN gene to invasive UM-UC-3 bladder tumour cells or expression of a dominant-negative version of the PI-3 kinase target, Akt, also potently inhibited invasion, indicating a central role for the PI-3 kinase/Akt pathway in this process. In addition, 55% of primary tumours from patients with bladder cancer had markedly high levels of phosphorylated Akt. CONCLUSION: Pharmacological or biochemical inhibition of the PI-3 kinase pathway drastically reduced the invasive capacity of bladder cancer cell lines; over half of primary human bladder tumours had high Akt phosphorylation, suggesting that the aberrant activation of this pathway may contribute to the invasion of a significant subset of bladder cancers.     

LRIG1, a candidate tumour-suppressor gene in human bladder cancer cell line BIU87

OBJECTIVES: To determine the effects of LRIG1 on the growth, migration and invasion of bladder cancer cells and the mechanisms underlying such effects. MATERIALS AND METHODS: The plasmid pLRIG1-green fluorescence protein (GFP) was transfected into BIU87 bladder cancer cells by Lipofectamine2000 (Invitrogen, Groningen, the Netherlands), and the cells that expressed LRIG1 stably were screened out by G418. The changes in LRIG1 and epidermal growth factor receptor (EGFR) protein levels were measured by Western blot; growth curves were estimated by the tetrazolium (MTT) assay; then cell-cell adhesion, cell-matrix adhesion and cell invasion assays were used to measure proliferation, adhesion and invasion in LGIR1-transfected and control cells. RESULTS: The LRIG1 protein level in pLRIG1-GFP transfected cells was significantly higher than that in control cells, while the EGFR protein level was significantly lower. pLRIG1-GFP transfected cells had less proliferation than control cells. Contrasting with non-LRIG1-transfected cells, the invasion and cell-matrix adhesion ability of pLRIG1-GFP transfected cells decreased markedly, and conversely the homotypic cell-cell adhesion ability was significantly higher. CONCLUSIONS: LRIG1 might act as a tumour-suppressor gene, participating in negative feedback control of EGFR expression, which inhibits bladder cancer cells from growth, migration and invasion.     

Novel prophylactic effect of doxifluridine in superficial bladder cancer

OBJECTIVES: The prophylactic effect of 5'-deoxy-5-fluorouridine (5'-DFUR) has not been fully studied in superficial bladder cancer. The aims of this work were to investigate the prophylactic effects of 5'-DFUR in terms of tumor recurrence after transurethral resection of bladder tumor (TURBT) and to study whether thymidine phosphorylase (TdRPase) immunostaining predicts tumor recurrence. MATERIAL AND METHODS: A total of 112 patients with pTa or pT1 bladder cancer were eligible for the analysis and were allocated to either an adjuvant group (TURBT+5'-DFUR; n = 47; initial 23 months) or a control group (TURBT alone; n = 65, final 23 months). Tumor specimens were studied immunohistochemically using anti-TdRPase antibody. RESULTS: Tumor recurrence was observed in 54 of the patients (48%) after a median follow-up period of 26.8 months. No significant clinico-pathologic bias was observed between the two groups. Although patients in the adjuvant group had a significantly higher recurrence-free survival rate than those in the control group when considering 78 patients with pathological T1 tumors (p = 0.0272) and 65 patients who did not recur within 12 months (p = 0.001), overall there was no significant difference between the two groups. Multivariate analysis revealed that 5'-DFUR administration was the strongest predictor of late tumor recurrence, which was defined as development of recurrence 12 months after TURBT (hazard ratio 5.744; 95% CI 1.495-30.45; p = 0.0094). Immunostaining did not predict prophylactic effects of 5'-DFUR. Mild, reversible toxicity was found in 9/58 (15.5%) of the cases evaluated. CONCLUSIONS: Oral administration of 5'-DFUR after TURBT did not prevent tumor recurrence in the overall cohort, although this novel drug may have a prophylactic effect in patients belonging to several subgroups.     

Heparanase protein and gene expression in bladder cancer

PURPOSE: We determined the association of heparanase protein and messenger (m)RNA expression with bladder cancer invasion and metastasis. MATERIALS AND METHODS: The expression of heparanase protein and mRNA was assessed by immunohistochemical staining and in situ hybridization, respectively, in 67 bladder cancer specimens resected at various stages of disease. To our knowledge this is the first systematic study of heparanase protein and mRNA expression in human bladder cancer. RESULTS: The expression of heparanase protein in muscular invasive bladder cancer was significantly higher than in superficial cancer (68% versus 19%, p = 0.0001). It was higher in the primary tumor of patients with lymph node metastatic cancer than those with nonmetastatic cancer (80% versus 37%, p = 0.0006). In high grade disease it was significantly higher than in low grade disease (79% versus 29%, p = 0.0001). The expression of heparanase mRNA was also significantly higher in stage pT3 or greater than in stage pT2 or less bladder cancer (96% versus 33%, p = 0.0003). In metastatic N+ cases it was significantly higher than in nonmetastatic bladder cancer (93% versus 46%, p = 0.0037). The heparanase gene and protein showed similar patterns of expression in bladder cancer. CONCLUSIONS: Our study implies that the expression of heparanase protein and mRNA is associated with bladder cancer invasion and metastasis, and heparanase may have a role in disease progression.     

膀胱癌细胞RT4和253J中转移相关蛋白的差异表达及意义

目的 检测转移相关蛋白上皮型钙黏素(E-cadherin)和波形蛋白(Vimentin)在膀胱癌细胞RT4和253J中的表达,从细胞黏附性和骨架蛋白角度探讨膀胱癌恶性进展的分子机制.方法 用Western blot法测定RT4和253J两种细胞中E-cadherin和Vimentin的表达差异,Millicell小室检测RT4和253J的体外侵袭能力,分析RT4和253J的细胞特性.结果 E-cadherin在RT4细胞中高表达、在253J细胞中低表达,而Vimentin在RT4细胞中表达缺失、在253J细胞中表达很高;Millicell证实253J细胞穿膜数较RT4细胞显著增多.结论 人膀胱癌细胞RT4和253J的E-cadherin、Vimentin表达及两种细胞的侵袭潜能差异无统计学意义,提示这两种蛋白的表达差异在促进或抑制膀胱癌的恶性进展中起重要作用.

Abstract：

Objective To detect the expression of metastasis-associated proteins in bladder cancer cells RT4 and 253J and explore the molecular mechanisms of malignant transition of bladder cancer. Methods The expression of E-cadherin and Vimentin in RT4 and 253J cells was detected by Western blotting.Millicell polycarbonate filter was used to analyze the invasive potency of RT4 and 253J cells. Results E-cadherin was detected with high expression in RT4 cells, whereas a very low expression in 253J cells:Vimentin was not detected in RT4 cells, but a high expression in 253J cells. Conclusion There was remarkable difference in the expressions of E-cadherin and Vimentin in RT4 and 253J cells, and there was different invasion characteristic in these two cell liness. E-cadherin and Vimentin play a key role in the malignant transition of bladder tumor.     

Serum levels of vascular endothelial growth factor as a prognostic factor in bladder cancer

PURPOSE: Vascular endothelial growth factor is an overriding growth factor mediating tumor angiogenesis. We correlated serum vascular endothelial growth factor in patients with bladder cancer with clinical parameters. MATERIALS AND METHODS: Serum vascular endothelial growth factor in 58 patients with bladder cancer, including superficial and invasive tumors in 42 and 16, respectively, and 41 healthy controls was measured by sandwich enzyme immunoassay. RESULTS: Significant differences in serum vascular endothelial growth factor were observed in healthy controls and patients with bladder cancer (mean 248 versus 100 pg./ml., p <0.001). The serum level was significantly associated with tumor stage (p <0.0001), grade (p <0.002), vascular invasion (p <0.001) and carcinoma in situ (p <0.01). Patients with metastasis had a significantly higher levels than those with localized diseases (mean 582 versus 194 pg./ml., p <0.0001). At a cut-off of 400 pg./ml. the sensitivity and specificity of the test for differentiating patients with and without metastatic diseases was 87.5% and 98%, respectively (p <0.0001). Univariate statistical analysis showed that an increase in serum vascular endothelial growth factor level greater than 400 pg./ml. was significantly related to disease-free survival. On multivariate analysis only stage remained as an independent prognostic factor. CONCLUSIONS: Although vascular endothelial growth factor did not remain an independent prognostic factor on multivariate analysis, our data indicate that the level of vascular endothelial growth factor may be a valuable angiogenic marker for identifying metastatic bladder cancer. It may be used as a new predictor of disease.     

Lactobacillus species is more cytotoxic to human bladder cancer cells than Mycobacterium Bovis (bacillus Calmette-Guerin)

PURPOSE: We determined if Lactobacillus species has growth inhibitory effects in human bladder cancer cell lines and how this effect compares with the known effects of Mycobacterium bovis, that is bacillus Calmette-Guerin (BCG). MATERIALS AND METHODS: The growth of MGH and RT112 cells were determined by cell counts after 24, 48 and 72 hours of exposure to L. casei strain Shirota (Yakult, Singapore) or L. rhamnosus strain GG (National Collection of Industrial and Marine Bacteria, Ltd., Aberdeen, Scotland) (1 x 10 and 1 x 10 cfu) or BCG (1 x 10 cfu) in the presence and absence of streptomycin. Annexin-V was used to monitor the presence of pre-apoptotic cells. RESULTS: L. rhamnosus GG inhibited MGH proliferation and it was cytotoxic to RT112 cells (p <0.05). L. casei Shirota was cytotoxic to the 2 cell lines (p <0.05). BCG had a similar cytotoxic effect in MGH cells as Lactobacillus species but was not as effective in RT112 cells. Streptomycin abrogated the cytotoxic effect of Lactobacillus species but not that of BCG. Cytotoxic activity was not found in Lactobacilli culture supernates but it was induced in the presence of mammalian cells. L. rhamnosus GG induced apoptosis in RT112 but not in MGH cells. No apoptotic cells were detected after treatment with L. casei Shirota. CONCLUSIONS: Lactobacillus species induced cytotoxic effects in bladder cancer cells. Unlike BCG, it requires bacterial protein synthesis. Like BCG, L. casei Shirota induces cell death primarily via necrosis. The cytoxicity of these lactobacilli in bladder cancer cells raises the possibility of using this species of bacteria as intravesical agents for treating bladder cancer.     

Expression of thymidine phosphorylase in human superficial bladder cancer

BACKGROUND: The purpose of the present paper was to investigate the expression level of thymidine phosphorylase (TPase) in superficial bladder cancer tissues obtained by transurethral resection, and determine whether its expression correlates with tumor recurrence. METHODS: From March 1998 to December 2001, 99 patients with superficial bladder cancer were diagnosed and treated at eight affiliated hospitals. Tissue specimens obtained by transurethral resection of superficial bladder cancer (TURBT) were applied to immunohistochemical study using anti-TPase antibody as well as pathological diagnosis. The data were subjected to statistical analysis. RESULTS: Using MoAb 654-1 as the primary antibody, TPase was clearly stained in human bladder cancer tissues. The maximum TPase level measured by enzyme-linked immunosorbent assay (ELISA) method in normal bladder tissues was 18.7 U/mg protein. The TPase activity was 2.8-fold higher in tumors than in normal bladder samples (P = 0.037). The TPase positivity rates determined by immunohistochemical and ELISA methods were distinctly correlated (P = 0.046). For the recurrence-free rates in pT1 tumors treated by TURBT alone (n = 46), there were no statistically significant differences between Tpase-positive or -negative cases. CONCLUSIONS: The TPase expression determined by ELISA and immunohistochemistry is significantly up-regulated in superficial bladder tumors compared with normal bladder samples. However, TPase expression by immunohistochemistry is not a predictive index of recurrence-free rate for superficial bladder cancer treated with TURBT alone.     

Expression and significance of vascular endothelial growth factor receptor 2 in bladder cancer

PURPOSE: Vascular endothelial growth factor has a critical role in maintaining tumor microvasculature and, as such, is an attractive target for anti-angiogenic therapy. Aberrant expression of VEGF receptors, especially VEGFR2, on epithelial tumor cells allows VEGF to stimulate growth and migration of tumor cells in an autocrine and/or paracrine manner. Therefore, we studied the expression of VEGF and VEGFR2 in bladder cancer, and the relationship to disease characteristics. MATERIALS AND METHODS: Expression of VEGF and VEGFR2 was studied in a cohort of 72 patients with transitional cell cancer of the bladder. Tumor tissues from all patients were analyzed by immunohistochemistry and examined by a pathologist blinded to patient outcome. Patient demographics and disease outcome were correlated with expression of these markers. Bladder cancer cell lines that express VEGFR2 were studied in vitro and in vivo to establish the significance of VEGF/VEGFR2 signaling. RESULTS: Expression of VEGF and VEGFR2 was observed in 58% and 50% of urothelial tumor cells, respectively. VEGF expression failed to correlate with clinical variables. However, VEGFR2 expression correlated with disease stage (coefficient 0.23, p = 0.05). In addition, VEGFR2 expression increased with tumor invasion into the muscle (p <0.01). Experiments with VEGFR2 positive bladder cancer cell lines in vitro demonstrated increased invasion in response to VEGF. In addition, VEGF inhibition augmented the effect of docetaxel in a murine xenograft model of bladder cancer with a significant inhibition in proliferative index and microvascular density, and induction of apoptosis. CONCLUSIONS: Increased VEGFR2 expression correlates with several features that predict progression of urothelial cancer, including disease stage and invasive phenotype. VEGF targeted therapy may enhance the efficacy of standard therapy for bladder cancer.     

Predicting the tumorigenic phenotype of human bladder cancer cells by combining with fetal rat mesenchyme

Background

In nonmuscle invasive bladder cancer patients, prediction of pTa and pT1 bladder cancer recurrence and progression must be established. Micropapillary structures have been defined as small clusters of invasive cancer cells having features of the epithelial-mesenchymal transition. Since the stromal microenvironment helps to induce the epithelial-mesenchymal transition, interactions between cancer cells and stroma should be closely examined to predict the tumorigenic phenotype of human bladder cancer cells.

Activation of cyclic AMP/PKA pathway inhibits bladder cancer cell invasion by targeting MAP4-dependent microtubule dynamics

ObjectiveWith the notorious reputation of the vicious invasion, the bladder cancer is the most common malignant tumor of the urinary system. Inhibiting invasion through microtubule dynamics interruption has emerged as an important treatment of bladder cancer. Here we investigated the role of the cyclic adenosine monophosphate/protein kinase A (cAMP/PKA) pathway in human bladder cancer cells invasion.Materials and methodsWith or without the treatment of various cAMP elevators, we assessed invasive and migrated capabilities of T24 and UM-UC-3, two high-grade invasive bladder cancer cell lines, using matrigel transwell inserts assay and scratch wound healing assay. The microtubule (MT) dynamics were examined by immunofluorescence and immunoblotting. Microtubule-Associated Protein 4 (MAP4) was silenced to investigate its role in tumor invasion. We also analyzed gene expression of MAP4 in 34 patients with bladder cancer using immunohistochemical staining assay. The interaction between PKA and MAP4 was examined by co-immunoprecipitation.ResultsWe used cAMP elevators and small interfering RNA of MAP4 here, found that both of them can potently inhibit the invasion and the migration of bladder cancer cells by disrupting microtubule (MT) cytoskeleton. Consistently, the bladder cancer grade is positively correlated with the protein level of MAP4. Furthermore, we found that cAMP/PKA signaling can disrupt MT cytoskeleton by the phosphorylation of MAP4.ConclusionOur results indicated that the cAMP/PKA signaling pathway might inhibit bladder cancer cell invasion by targeting MAP4-dependent microtubule dynamics, which could be exploited for the therapy of invasive bladder cancer.