Expression of platelet-derived endothelial cell growth factor/thymidine phosphorylase in human bladder cancer

The dual role of thymidine phosphorylase in cancer development and chemotherapy

Thymidine phosphorylase (TP), also known as "platelet-derived endothelial cell growth factor" (PD-ECGF), is an enzyme, which is upregulated in a wide variety of solid tumors including breast and colorectal cancers. TP promotes tumor growth and metastasis by preventing apoptosis and inducing angiogenesis. Elevated levels of TP are associated with tumor aggressiveness and poor prognosis. Therefore, TP inhibitors are synthesized in an attempt to prevent tumor angiogenesis and metastasis. TP is also indispensable for the activation of the extensively used 5-fluorouracil prodrug capecitabine, which is clinically used for the treatment of colon and breast cancer. Clinical trials that combine capecitabine with TP-inducing therapies (such as taxanes or radiotherapy) suggest that increasing TP expression is an adequate strategy to enhance the antitumoral efficacy of capecitabine. Thus, TP plays a dual role in cancer development and therapy: on the one hand, TP inhibitors can abrogate the tumorigenic and metastatic properties of TP; on the other, TP activity is necessary for the activation of several chemotherapeutic drugs. This duality illustrates the complexity of the role of TP in tumor progression and in the clinical response to fluoropyrimidine-based chemotherapy.

Uroplakin III-delta4 messenger RNA as a promising marker to identify nonulcerative interstitial cystitis

PURPOSE

Interstitial cystitis remains a poorly understood urological condition characterized by chronic pelvic pain and increased urinary frequency in the absence of any known etiology. Urothelial dysfunction and other abnormalities are presumed to be involved in the disease. Uroplakins that are expressed by urothelial cells are thought to have an important role as major barrier proteins on the apical surface of the urothelium.

MATERIALS AND METHODS

Gene expression of uroplakin Ia, Ib, II, III and III-delta4 was quantitatively measured in bladder biopsy samples from 29 patients with interstitial cystitis and 16 control subjects using real-time reverse transcriptase-polymerase chain reaction.

RESULTS

The mRNA levels of the uroplakin Ia, Ib and II genes were relatively low and uroplakin III was relatively high in interstitial cystitis bladders compared to normal controls, although not significantly. Uroplakin III-delta4, a splicing variant of uroplakin III, was significantly up-regulated in interstitial cystitis samples (p <0.001). When patients with interstitial cystitis were divided into those with and without ulcerative changes, the uroplakin III and III-delta4 genes were significantly up-regulated only in patients with nonulcerative interstitial cystitis. Even more interesting was the finding that up-regulation of uroplakin III-delta4 was much more prominent than that of uroplakin III, that is 26.5 vs 5.6-fold compared to the median values of normal subjects.

CONCLUSIONS

Although the clinical implications of the over expression of uroplakin III and III-delta4 in nonulcerative interstitial cystitis bladders remains to be clarified, from the diagnostic viewpoint uroplakin III-delta4 is a potential marker for identifying nonulcerative interstitial cystitis.

Tissue levels of pyrimidine nucleoside phosphorylase activity in human and rodent bladder cancer and normal bladder tissue

OBJECTIVES

To assess the relationship between the tissue levels of pyrimidine nucleoside phosphorylase (PyNpase) and clinicopathological parameters in human bladder cancer and to investigate the PyNpase levels in rat and mouse urinary bladder initiated by N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN).

METHODS

The PyNpase levels in tumor tissue, normal tissue adjacent to the tumor, and normal tissue apart from the tumor were measured in 102 patients. Additionally, the PyNpase levels were measured in rat and mouse urinary bladders treated with BBN.

RESULT

The PyNpase levels of tumor tissue significantly correlated to the tumor grade and growth pattern (papillary/non-papillary), while stage, multiplicity, and tumor shape (peduncle/sessile) were not independent factors. The low-risk tumor of primary, single, G1-Ta showed significantly low levels of PyNpase. The PyNpase levels in the tumor tissue were significantly higher than those in the normal tissue. The PyNpase levels in the adjacent normal tissue were significantly higher than those in the distant normal tissue. The PyNpase levels in rat bladder tissue were significantly higher in the BBN-treatment groups than in those in the control group, only during the early carcinogenic stage. The PyNpase levels in mouse bladder tissue were significantly higher in BBN-treatment groups than in those in the control group during the whole experiment period.

CONCLUSION

Our results indicated that not only tumor tissue but also normal tissue adjacent to the tumor had a potential of angiogenesis for tumor development, and transurethral resection of the bladder tumor with a wide normal margin seems to be a reasonable strategy for decreasing the risk of recurrence.

The expression of thymidine phosphorylase is a prognostic predictor for the intravesical recurrence of superficial bladder cancer

BACKGROUND

Thymidine phosphorylase (TP), also known as platelet-derived endothelial cell growth factor, has been implicated in the angiogenesis of bladder cancer. The aim of this study is to investigate the association between TP expression and the clinicopathologic findings, and the prognostic value.

METHODS

TP immunohistochemical staining was performed in specimens from 71 patients (50 men and 21 women) with superficial bladder cancer (pTa or pT1). Thirty-nine patients had received intravesical instillation of tetrahydropyranyladriamycin (THP) after transurethral resection (TUR) and the other 32 had not. For immunohistochemistry, paraffin-embedded specimens were stained with mouse monoclonal antibody against TP. When more than 10% of tumor cells were positively stained, staining was defined as positive. The correlations between TP immunostaining and clinicopathological features were analyzed. Multivariate analysis, using the Cox proportional hazard model, was performed to determine the risk factors for intravesical recurrence.

RESULTS

Specimens from 29 of the 71 patients (19 men and 10 women) were positive for TP. The expression of TP was not correlated with age, sex, histological grade, multiplicity, or morphology. Also, TP expression was not associated with whether the cases were primary or recurrent. Multivariate analysis demonstrated that the decreased expression of TP and the use of THP instillation could be independent predictors of a higher rate of intravesical recurrence-free bladder cancer.

CONCLUSION

The present study suggests that immunohistochemical TP staining is useful for predicting the intravesical recurrence of superficial bladder cancer after Transurethral resection of bladder tumor (TUR-Bt).

High expression of human uroplakin Ia in urinary bladder transitional cell carcinoma

Uroplakins (UPs) Ia, Ib, II, and III are tissue-specific and differentiation-dependent transmembrane proteins of the urothelium. We assessed the usefulness of human UP Ia as a histological marker by examining its expression in urinary bladder transitional cell carcinoma (TCC). A polyclonal antibody against human UP Ia was raised using a synthesized polypeptide. We applied our antibody to various organ tissues, including urothelium, and observed no crossreactivity. Analysis by RT-PCR of normal urothelium, TCC and other organ tissues indicated that the human UP Ia gene expression is highly specialized to urothelium, and is conserved in TCC. Using immunohistochemistry, we investigated the expression of UP Ia in TCC from patients who had undergone radical cystectomy and from autopsy cases. Positive staining (10% or more positive cancer cells) was noted in primary lesions from 61 of 63 (96.8%) cystectomy patients. Depending on pathological grade, high expression (50% or more positive cancer cells) was observed in 17 of 18 (94.4%) moderately- to well-differentiated TCC and in 36 of 45 (80.0%) poorly differentiated TCC. With regard to tumor invasion, high expression was noted in 20 of 22 (90.9%) superficial and 33 of 41 (80.5%) muscle-invasive TCC. Cause-specific survival rates were 68.6% and 75.0% in high- and low-expression patients, respectively (log-rank test, P = 0.855, mean follow-up; 65.0 months). In metastases, positive reactions were observed in 13 of 18 (72.2%) lesions. UP Ia may represent a specific histological marker judging from the stable expression, although its value as a prognostic factor remains undetermined.

Suppression of tumor growth and downregulation of platelet-derived endothelial cell growth factor / thymidine phosphorylase in tumor cells by angiogenesis inhibitor TNP-470

We investigated the effects of the angiogenesis inhibitor TNP-470 on human lung squamous cell carcinoma cell lines H226B and H226Br both in vivo and in vitro. H226B was established from human lung squamous cell carcinoma and H226Br was established from a brain metastatic lesion of H226B in nude mice. Nude mice inoculated with these cells were treated with 30 mg / kg of TNP-470 subcutaneously every other day. At this dose, TNP-470 only significantly suppressed the growth of H226Br tumor, but not H226B tumor. Attempts to use a high dose of TNP-470 (100 mg / kg) resulted in a severe loss of body weight. Immunohistochemical studies showed marked tumor vascularization in H226Br tumor, but the formation of new blood vessels was suppressed by 30 mg / kg of TNP-470. Investigation of the mechanism of anti-angiogenic effects of TNP-470 in vivo showed that the expression and the activity of platelet-derived endothelial cell growth factor / thymidine phosphorylase (PD-ECGF / dThdPase) in H226Br tumor was significantly suppressed by 30 mg / kg of TNP-470. Furthermore, TNP-470 inhibited cell growth of cultured H226Br dose-dependently at concentrations of 1 microg / ml. Immunoblot analysis revealed H226Br cells gave a stronger PD-ECGF signal than H226B cells, and the expression of PD-ECGF / dThdPase in H226Br was also suppressed by treatment with TNP-470 at 0.1 microg / ml. No change in basic fibroblast growth factor (bFGF) or vascular endothelial growth factor (VEGF) was noted in these cell lines. Our results suggested that TNP-470 acts, at least in part, by downregulation of PD-ECGF / dThdPase in this cell line.