Tumor angiogenesis and expression of thymidine phosphorylase/platelet derived endothelial cell growth factor in human gastric carcinoma

Activation of Stat1, IRF-1, and NF-kappaB is required for the induction of uridine phosphorylase by tumor necrosis factor-alpha and interferon-gamma

Uridine phosphorylase (UPase) has been shown to be induced in various human and murine tumors and could potentially serve as a specific target for the modulation of tumor-selectivity of fluoropyrimidines. However, the signaling mechanisms underlying the regulation of UPase gene expression have not been determined. In this study, we investigated the effects of IFN-gamma on the regulation of TNF-alpha-induced UPase activity and have uncovered the molecular mechanisms of this potentiation, utilizing murine EMT6 breast cancer cells. Our data has shown that IFN-gamma can significantly increase UPase mRNA expression and the enzymatic activity induced by TNF-alpha in a dose-dependent manner, resulting in an enhanced sensitivity to 5-fluorouracil (5-FU) and 5'-Deoxy-5-fluorouridine (5'DFUR). We have previously shown that TNF-alpha activates NF-kappaB through increased translocation of NF-kappaB p65 from the cytoplasm into the nuclei. Exposure to IFN-gamma mainly affects nuclear IRF-1 and STAT1 in EMT6, but inhibits NF-kappaB p65 activity, indicating that the cooperative stimulation was the result of the independent activation of NF-kappaB, STAT1 and IRF-1 transcriptional factors through binding to their unique sites in the UPase promoter. Notably, the activation of NF-kappaB and STAT1 in human breast tissues is consistent with UPase activity; signifying their role in the up-regulation of the UPase gene expression in human tumors.

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.

Toward molecularly selected chemotherapy for advanced gastric cancer: state of the art and future perspectives

In the last few years therapeutic options for gastric cancer patients have slowly, but constantly expanded following the introduction of both new chemotherapy agents and innovative indications for treatment. Along with the medical therapy also our knowledge of the molecular mechanisms underlying this disease has progressively improved. However although the available treatment options have undoubtedly increased no clear definitive indications can be made for a standard chemotherapy regimen and we are still unable to accurately select the appropriate treatment for the appropriate patient. Many molecular determinants of response/toxicity to chemotherapy agents have been identified, but only few of them seem to possess the necessary potential for a subsequent application in the clinical practice. Some of these factors have also been indicated as a therapeutic target for a novel class of anti-cancer compounds. This systematic review will analyse available data about these factors with the aim to constitute a starting point for future research.

Biomarker analysis in stage III-IV (M0) gastric cancer patients who received curative surgery followed by adjuvant 5-fluorouracil and cisplatin chemotherapy: epidermal growth factor receptor (EGFR) associated with favourable survival

The aim of this study was to analyse the impact of epidermal growth factor receptor (EGFR), thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD), thymidine phosphorylase (TP), aurora kinase (ARK) A/B, and excision repair cross-complementing gene 1 (ERCC1) on the efficacy of adjuvant chemotherapy with 5-fluorouracil and cisplatin (FP) after curative gastric resection. Normal and cancer tissue were separately obtained from gastrectomy samples of 153 patients with AJCC stage III–IV (M0) who subsequently treated with adjuvant FP chemotherapy. TS, DPD, TP, ERCC1, and ARK proteins were measured by immunohistochemistry (IHC). EGFR expression was investigated using a standardized IHC with the EGFR PharmDx assay. Amplification of EGFR gene was analysed using fluorescent in situ hybridisation (FISH). In multivariate analysis, stage, ratio of positive to removed lymph nodes, and EGFR expression were significant prognostic factors for overall survival. Patients with higher EGFR expression had better overall survival than those with lower expression (relative risk: 0.475 (95% confidence interval, 0.282–0.791, P=0.005). Low EGFR expression might be a predictive marker for relapse in curative resected stage III–IV (M0) gastric cancer patients who received adjuvant FP chemotherapy.

The expression of thymidine phosphorylase in cancer-infiltrating inflammatory cells in stomach cancer

Thymidine phosphorylase (TP) has shown to be up-regulated in several cancers and to play a role in angiogenesis and invasion. Most studies regarding TP have focused on cancer cells. Recently, evidences suggest that TP in cancer-infiltrating inflammatory cells (CIICs) also affect the cancer cell behavior. To evaluate the significance of TP expression of CIICs in gastric cancer, we assessed TP expression of cancer cells and CIICs separately using immunohistochemical assay on 116 paraffin-embedded tissue samples from stomach cancer patients and investigated their clinical significance. When subjects were divided into 4 groups according to the TP expression: cancer/matrix (+/+), C/M (+/-), C/M (-/+), and C/M (-/-), intratumoral microvessel density scores were higher in the C/M (+/-) group than in the C/M (-/-) group (p=0.02). For lymph node metastasis and survival, there were no significant differences among the 4 groups. However, there were significant differences in survival (p=0.035) and LN metastasis (p=0.023) between the two groups divided by TP expression of CIICs alone irrespective of TP expression of cancer cells. Taken together, this study suggested the TP expression in CIICs could affect lymph node metastasis and patients' survival in gastric cancer.

Modulation of thymidine phosphorylase by neoadjuvant chemotherapy in primary breast cancer

The combination effect of docetaxel and capecitabine on tumour response rate and survival was demonstrated recently in metastatic breast cancer patients. This combination was based on an experimental hypothesis that taxane can increase tumour sensitivity to the effect of capecitabine through the upregulation of thymidine phosphorylase (TP), which is responsible for the metabolism of 5-fluorouracil (5-FU) and its derivatives, including capecitabine. To examine the alteration in TP expression before and after neoadjuvant chemotherapy, 92 patients with primary breast cancer (T2-4N0-1M0) were enrolled in this study; 14 were treated with adriamycin and cyclophosphamide (AC) or epirubicin and cyclophosphamide (EC); 58 with 5-FU, adriamycin, and cyclophosphamide (FAC) or 5-FU, epirubicin, and cyclophosphamide (FEC); and 20 with FEC followed by docetaxel/taxotere (TXT-containing regimen). Thymidine phosphorylase upregulation was seen in 54.4% and 32.6% of patients in tumour cells and stromal cells, respectively. Increases in TP expression were found only in the AC/EC and TXT-containing regimen groups. In conclusion, it was strongly suggested that unlike 5-FU-containing regimens, the taxane and AC combination therapies upregulate TP expression in primary breast cancer. Thymidine phosphorylase upregulation by several anticancer drugs implies the importance of individualised strategies for sensitisation of tumour tissues to 5-FU and its derivatives.

Prediction of sensitivity to fluoropyrimidines by metabolic and target enzyme activities in gastric cancer

BACKGROUND

This study was designed to investigate the role of thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD), and thymidine phosphorylase (TP) in tumor progression and sensitivity to 5-fluorouracil (5-FU).

METHODS

A total of 275 tumor samples from 275 patients with gastric cancer were utilized in this study. TS activity was determined in 130 samples by 5-fluorodeoxyuridine monophosphate binding assay. DPD activity was measured in 140 samples by radioenzymatic assay, and TP protein level was determined in 157 samples by an enzyme-linked immunosorbent assay (ELISA) system. These parameters were compared with several clinicopathologic factors and sensitivity to 5-FU determined by in-vitro ATP assay. The antitumor activities of 5-FU, uracil plus tegafur (UFT), and 1M tegafur--0.4 M 5-chloro-2,4-dihydroxypyridine--1 M potassium oxonate (S-1 [TS-1]) were also compared, using three human gastric cancer xenografts in nude mice.

RESULTS

There was no correlation between either TS or TP and sensitivity to 5-FU. However, a weak inverse correlation was found between DPD activity and sensitivity to 5-FU. High DPD activity in tumor resulted in poor prognosis, especially in patients who received 5-FU-based adjuvant chemotherapy. Although TP was significantly correlated with depth of tumor invasion and with lymphatic and venous invasions, TP alone had no impact on survival. On the other hand, TS, as well as peritoneal, hepatic, and lymph node metastases, was selected as an independent prognostic factor in gastric cancer. In the animal model, there was no significant difference in antitumor activities among the drugs in a tumor with low DPD activity. However, S-1 showed superior antitumor activity to 5-FU or UFT in tumors with high DPD activity.

CONCLUSION

DPD is considered to be a most important predictive factor of 5-FU sensitivity. The use of DPD inhibitory fluoropyrimidines is strongly recommended for tumors with high DPD activity.

Clinical significance of angiogenesis in gastrointestinal cancers: a target for novel prognostic and therapeutic approaches

OBJECTIVE

To review the current data on the prognostic and therapeutic implications of tumor angiogenesis in gastrointestinal cancers.

SUMMARY BACKGROUND DATA

Numerous studies have evaluated the prognostic value of tumor angiogenesis and the potential role of antiangiogenic therapy in various gastrointestinal cancers.

METHODS

A Medline literature search was conducted using "angiogenesis" or the names of various angiogenic factors in combination with the names of gastrointestinal cancers as the key words.

RESULTS

Several studies have demonstrated a significant prognostic impact of tumor microvessel density and tumor expression of angiogenic factors, in particular vascular endothelial growth factor (VEGF), in various gastrointestinal cancers. A few studies have suggested that circulating VEGF might be a useful prognostic marker. However, results were not consistent across all studies and were limited by the retrospective nature of most studies. Antiangiogenic therapy has been shown to be effective against all common gastrointestinal cancers in preclinical studies, but currently there are few clinical data with regard to antiangiogenic therapy in gastrointestinal cancers.

CONCLUSIONS

There is mounting evidence to suggest that assessment of tumor angiogenesis might provide a novel approach of prognostication in patients with gastrointestinal cancers. However, current results from retrospective studies need to be validated by prospective studies. Antiangiogenic therapy is a promising strategy of cancer treatment that might be particularly useful in combination therapy for unresectable cancers or as an adjuvant therapy for resectable tumors.

Clinical significance of angiogenesis in gastrointestinal cancers: a target for novel prognostic and therapeutic approaches

OBJECTIVE

To review the current data on the prognostic and therapeutic implications of tumor angiogenesis in gastrointestinal cancers.

SUMMARY BACKGROUND DATA

Numerous studies have evaluated the prognostic value of tumor angiogenesis and the potential role of antiangiogenic therapy in various gastrointestinal cancers.

METHODS

A Medline literature search was conducted using "angiogenesis" or the names of various angiogenic factors in combination with the names of gastrointestinal cancers as the key words.

RESULTS

Several studies have demonstrated a significant prognostic impact of tumor microvessel density and tumor expression of angiogenic factors, in particular vascular endothelial growth factor (VEGF), in various gastrointestinal cancers. A few studies have suggested that circulating VEGF might be a useful prognostic marker. However, results were not consistent across all studies and were limited by the retrospective nature of most studies. Antiangiogenic therapy has been shown to be effective against all common gastrointestinal cancers in preclinical studies, but currently there are few clinical data with regard to antiangiogenic therapy in gastrointestinal cancers.

CONCLUSIONS

There is mounting evidence to suggest that assessment of tumor angiogenesis might provide a novel approach of prognostication in patients with gastrointestinal cancers. However, current results from retrospective studies need to be validated by prospective studies. Antiangiogenic therapy is a promising strategy of cancer treatment that might be particularly useful in combination therapy for unresectable cancers or as an adjuvant therapy for resectable tumors.

Role of thymidine phosphorylase and dihydropyrimidine dehydrogenase in tumour progression and sensitivity to doxifluridine in gastric cancer patients

This study was designed to investigate the role of thymidine phosphorylase (TP) and dihydropyrimidine dehydrogenase (DPD) on tumour progression and sensitivity to 5'-deoxy-5-fluorouridine (5'-DFUR). Tumour tissue was obtained from surgically resected samples from 93 patients with primary gastric cancer. Tumour TP and DPD expression levels were determined by the enzyme-linked immunosorbent assay (ELISA) system and compared with several clinicopathological factors and in vitro sensitivity to 5'-DFUR. DPD showed no correlation with any clinicopathological factors. However, the TP level was significantly correlated with the depth of tumour, lymphatic invasion and venous invasion. In comparison with 5'-DFUR sensitivity, there was a weak inverse correlation between the DPD level and the sensitivity to 5'-DFUR (r(s)=-0.361). Furthermore, the TP/DPD ratio showed a significant correlation with 5'-DFUR sensitivity (r(s)=0.634). In a subgroup of patients with postoperative 5'-DFUR administration, the survival rate was significantly better in patients with a high TP/DPD ratio (n=8) than in those with low TP/DPD ratio (n=14) (P=0.0140). These results suggest that sensitivity to 5'-DFUR is predictable by measurement of both TP and DPD levels.

A phase I and pharmacokinetic study of capecitabine in combination with epirubicin and cisplatin in patients with inoperable oesophago-gastric adenocarcinoma

BACKGROUND

The purpose of this study was to evaluate the dose-limiting toxicity (DLT) and maximum tolerated dose of capecitabine when used in combination with epirubicin and cisplatin (ECC) in patients with oesophageal or gastric adenocarcinoma. Response rate, progression-free survival (PFS) and overall survival were also determined, and the effect of previous oesophago-gastric surgery or concurrent oesophago-gastric cancer on the absorption and metabolism of capecitabine was evaluated.

PATIENTS AND METHODS

Patients with inoperable oesophago-gastric adenocarcinoma received up to six cycles of epirubicin (50 mg/m(2) i.v., 3-weekly), cisplatin (60 mg/m(2) i.v., 3-weekly) and capecitabine, the latter administered orally in an intermittent schedule (14 days treatment; 7-day rest period) at 3-weekly intervals. Patients were recruited into one of four escalating dose cohorts (500, 825, 1000 and 1250 mg/m(2) bd). Dose escalation occurred after six patients had completed at least one cycle of chemotherapy at the previous dose level, with DLT assessed on the toxicity of the first cycle only. Blood sampling for pharmacokinetic analyses was performed over the first 10 h of day 1 of cycle 1.

RESULTS

Thirty-two patients, median age 63 years (range 32-76 years), ECOG performance status < or =2 with locally advanced (10) or metastatic (22) disease were recruited and were evaluable for toxicity. Two of five patients experienced DLT at 1250 mg/m(2) bd with grade II stomatitis (one patient) and grade III diarrhoea with febrile neutropenia (one patient). Cumulative toxicity for all cycles (n = 140) (worst grade per patient) includes grade IV oesophagitis (one patient), grade III diarrhoea (five), grade IV neutropenia with infection (seven), grade II stomatitis (four) and grade IV thrombocytopenia (one). Of 29 patients with evaluable disease, there was one complete response and six partial responses [24% response rate [95% confidence interval (CI) 10% to 44%]], a median PFS of 22 weeks (95% CI 17-27 weeks) and median overall survival of 34 weeks (95% CI 19-49 weeks). Capecitabine was rapidly absorbed after oral administration, with a t(max) of 1-2 h for capecitabine, DFCR (5'-deoxy-5-fluorocytidine) and DFUR (5'-deoxy-5-fluorouridine). The C(max) and AUC(0-)( infinity ) for capecitabine, DFCR and DFUR were similar to those observed in previous monotherapy studies of capecitabine taken after food.

CONCLUSION

A dose of 1000 mg/m(2) bd of capecitabine is recommended for use on an intermittent schedule in combination with these doses and schedule of epirubicin and cisplatin. This regimen is tolerable and active in oesophago-gastric adenocarcinoma. A randomised phase III comparison with ECF is justified.

Prognostic value of thymidine phosphorylase/platelet-derived endothelial cell growth factor in advanced colorectal cancer after surgery: evaluation with a new monoclonal antibody

BACKGROUND

Thymidine phosphorylase (TP) is an essential enzyme for activation of 5-fluorouracil and its derivatives and identical to platelet-derived endothelial cell growth factor. In colorectal cancer (CRC), previous studies evaluating the relationship between TP expression and clinicopathologic features have yielded inconsistent results. These studies used monoclonal antibody 654-1, which stained CRC cells weakly. Now, a new monoclonal antibody, 1C6-203, more sensitive than 654-1, is available.

METHODS

This study included 80 patients whose CRCs were classified into stages II to IV and completely resected surgically in our institute. TP expression in CRC was evaluated by using immunohistochemical staining with 1C6-203. Relationships between TP expression and clinicopathologic variables that might have affected the patients' prognosis were evaluated. Survival curves were calculated with the Kaplan-Meier method, and differences were evaluated with log-rank test. Cox proportional hazards model was used in the univariate and multivariate survival analyses.

RESULTS

TP expression showed a positive correlation with advances in histologic differentiation (P =.025), lymph node metastasis (P =.083), lymphatic invasion (P =.049), venous invasion (P =.042), and cancer stage (P =.002). The patients' survival rates after surgery were higher (P =.0041) in those with negative TP than in those with positive TP. The overall estimated hazard ratio for death in patients with TP expression was 6.24 according to univariate analysis (P =.013). Multivariate analysis showed that TP was a significant prognostic factor adjusted for other clinicopathologic variables.

CONCLUSIONS

With a new highly sensitive monoclonal antibody to TP, the present results indicated that TP expression is associated with CRC progression and invasion and closely correlated with poor prognosis in postoperative CRC patients. Moreover, TP expression is an independent prognostic factor in CRC patients.

Significance of angiogenesis and microvascular invasion in renal cell carcinoma

The aim of this study is to evaluate the relationship between tumor angiogenesis and microvascular invasion, and the subsequent development of metastatic disease in patients undergoing surgery for renal cell carcinoma (RCC). The study group consisted of 102 patients who underwent surgery for RCC between the years 1990 and 1997 in our institute with a mean follow up period of 81.3 months. Paraffin blocks were stained for Factor VIII - related antigen and CD34 which decorate endothelial cells in order to assess angiogenesis and microvascular invasion and their relevance for developing metastatic disease. When Factor VIII- related antigen staining was used we found that the microvessel count correlated with the development of metastatic disease with a mean count of 49.7 for patients with no evidence of disease and a mean count of 95.5 for patients who developed metastatic disease (p<0.05). We also found that microvascular invasion correlated with the development of metastatic disease. It was demonstrated in 55.5% of patients who developed metastatic disease versus 23.8% of patients with no evidence of disease with Factor VIII staining (p<0.05), and in 33.3% and 7.1%, respectively (p<0.05) with CD34 staining. This study suggest that demonstration of intense angiogenesis and micro-vascular invasion may be a predictor of a more aggressive tumor mandating closer follow up and consideration of adjuvant therapy.

Angiogenic effect of thymidine phosphorylase on macrophages in glioblastoma multiforme

OBJECT

Thymidine phosphorylase (TP) and vascular endothelial growth factor (VEGF) are known angiogenic factors; however, there are few reports in which the relationship between these two factors is addressed. The authors compared expression patterns of TP and VEGF and investigated their role in the angiogenesis of glioblastoma multiforme (GBM).

METHODS

Surgical specimens from 41 cases of GBM were immunohistochemically stained for TP, VEGF, CD68 (a macrophage marker), and CD31 (an endothelial cell marker). Both TP labeling indices and VEGF immunoreactivity displayed significant correlations with vascular density. Although VEGF was diffusely distributed in the tumor, TP was strongly expressed around blood vessels and in vascular proliferation. Double labeling for TP and CD68 in 10 cases indicated that cells that reacted strongly positive for TP were almost always macrophages, and only small numbers of CD68-negative cells weakly expressed TP. The TP messenger (m)RNA expression was investigated using reverse transcription-polymerase chain reaction in six GBMs. All six specimens expressed TP mRNA. In addition, TP mRNA was detected in two of three groups of cultured GBM cells derived from surgical specimens. Macrophages, the production of which was induced from two volunteers' peripheral blood monocytes by applying macrophage colony-stimulating factor, also expressed TP mRNA. The glioma cell lines U251MG and U87MG, which barely express TP mRNA under normal conditions, expressed TP mRNA in response to interferon-beta stimulation or while in an anoxic condition.

CONCLUSIONS

Although it is feasible that GBM cells can express TP depending on their growing conditions, the majority of TP-expressing cells present in GBMs appear to be infiltrating macrophages. Coexistence of VEGF and TP may indicate a synergistic upregulation for angiogenesis because VEGF exerts a chemotactic activity on macrophages that express TP.

Clinicopathological and prognostic significance of thymidine phosphorylase and proliferating cell nuclear antigen in gastric carcinoma

We have reported that thymidine phosphorylase (dThdPase) is identical to platelet derived-endothelial cell growth factor and that it has an angiogenic activity in vitro and in human carcinoma tissues as well as gastric carcinoma. Recently, we revealed that dThdPase may have an another function(s) besides angiogenesis in vitro and in human solid tumors. Using immunohistochemistry, we examined retrospectively whether the expression of dThdPase was correlated with tumor growth, comparing it with the proliferating cell nuclear antigen labeling index (PCNA LI) and examining their prognostic significance in 116 patients with gastric carcinoma. A direct correlation of these two factors was observed (R=0.659, P<0.001). A multivariate Cox regression analysis showed that both dThdPase positivity and PCNA LI were independent prognostic factors, as were depth of invasion and lymph node metastasis. Furthermore, the patients with dThdPase-positive/high PCNA LI tumors had the worst prognoses. The combination of dThdPase and PCNA expression is a better tool for predicting the prognosis of patients with gastric carcinoma than the expression of either of them alone. These results raise the possibility that dThdPase may have a function(s) involved in tumor growth besides angiogenesis.

Correlation between thymidine phosphorylase expression and invasion phenotype in cervical carcinoma cells

The correlation between thymidine phosphorylase (dThdPase) expression and invasion phenotype in human uterine cervical carcinoma cells was investigated using 10 cervical carcinoma cell lines. Semi-quantitative reverse transcription-polymerase chain reaction analysis was performed to investigate the mRNA levels of dThdPase and matrix metalloproteinase (MMP)-2 with beta-actin coamplified as an internal standard. dThdPase protein expression levels were detected by highly sensitive enzyme-linked immunosorbent assay. Tumor cell migration along a gradient of substratum-bound fibronectin and invasion into reconstituted basement membrane were evaluated by haptotactic migration and invasion assay. Although dThdPase mRNA and protein expression levels differed remarkably among the cell lines, there was a statistical correlation between them (r = 0.743, p = 0.0139). dThdPase gene and protein expression levels were well correlated with the number of cells that migrated and invaded (p < 0.05). Moreover, there was a close correlation between MMP-2 gene and dThdPase gene and protein expression levels (p < 0.05). Tumor cells that produce dThdPase may have a higher invasive and metastatic potential because of their capacity to pass through tissue barriers.

Thymidine phosphorylase expression causes both the increase of intratumoral microvessels and decrease of apoptosis in human esophageal carcinomas

Thymidine phosphorylase (dThdPase)/platelet-derived endothelial cell growth factor, is expressed at higher levels in tumor tissues compared to the adjacent normal tissues in a variety of human carcinomas. The higher expression is associated with an increase of intratumoral microvessel density (IMVD) and an unfavorable patient prognosis. We examined the role of dThdPase in apoptosis, IMVD, P53 expression and patient prognosis of human stages II and III esophageal squamous cell carcinomas (SCC). dThdPase expression was noted in 52 of the 78 esophageal SCC (66.7%), regardless of tumor stages and histologic grades. Mean IMVD was 117.9 +/- 32.6 in the dThdPase-positive cases and 103.1 +/- 21.5 in the dThdPase-negative cases, the value being significantly higher in the former (P < 0.05). Similarly, median (range) apoptotic index (AI: percentage of apoptotic cells) was significantly lower in the dThdPase-positive SCC, 1.8 (0.4-6.5), than in the dThdPase-negative SCC, 3.7 (0.6-7.0) (P < 0.01). AI and IMVD showed a significant inverse correlation (r = - 0.31, P = 0.005). There was also no significant difference in the frequency of P53 expression between the dThdPase-positive SCC and the negative SCC. No statistical difference was noted regarding the postoperative survival rate between the dThdPase-positive and the negative SCC. Although dThdPase expression was not associated with patient prognosis, the expression provided an advantage for tumor growth of human esophageal SCC, not only by increasing the intratumoral microvessels, but also attenuation of apoptosis, which might occur via a p53 gene-independent pathway.

Development and characterization of 1C6-203, a new monoclonal antibody specific to human thymidine phosphorylase

Thymidine phosphorylase (dThdPase) is an essential enzyme for activation of the oral cytostatic drug capecitabine and its intermediate metabolite, doxifluridine, to 5-fluorouracil in tumors. Methods to estimate dThdPase expression in tumor tissue might be useful to predict the efficacy of capecitabine and doxifluridine in cancer patients. We established a new monoclonal antibody (MAb), 1C6-203, applicable for dThdPase immunohistochemistry and compared its staining characteristics with those of a previously established MAb, 654-1. In 4% paraformaldehyde-fixed colorectal carcinoma, 1C6-203 and 654-1 stained cancer cells in 19/30 and 9/30 patients, respectively. In 10% formalin-fixed colorectal carcinoma, 1C6-203 and 654-1 stained cancer cells in 18/30 and 6/30 patients, respectively. In negative 10% formalin-fixed tissues, microwave treatment improved the positivity of 654-1-stained cancer cells. These results suggest that an epitope recognized by 1C6-203 is resistant to epitope masking by formaldehyde fixation, whereas that for MAb 654-1 is sensitive. Therefore, MAb 1C6-203 might be more suitable than MAb 654-1 for evaluating dThdPase expression in colorectal carcinoma.

Prognostic significance of expression of thymidine phosphorylase and vascular endothelial growth factor in human gastric carcinoma

BACKGROUND AND OBJECTIVES

Both thymidine phosphorylase (dThdPase) and vascular endothelial growth factor (VEGF) are well-characterized inducers of angiogenesis. The purpose of this study was to examine the expression of these antigens and their prognostic significance in gastric carcinoma.

METHODS

Medical records of 102 patients with stage II tumor were retrospectively reviewed. Primary tumors were studied by immunohistochemical staining for dThdPase and VEGF.

RESULTS

Positive dThdPase expression was observed in 52 (51%) tumors and positive VEGF expression in 53 (52%) tumors. There was a significant correlation between the positive expression of VEGF and lymphatic invasion. The patients with dThdPase-positive carcinoma showed a significantly worse prognosis than those with dThdPase-negative carcinoma in stage II. Moreover, the frequency of hepatic recurrence was significantly higher in the patients with dThdPase-positive and VEGF-positive tumors than in those with dThdPase-negative and VEGF-negative tumors.

CONCLUSIONS

Combination analysis of dThdPase and VEGF expression in gastric carcinoma appears to be well-characterized inductors of prognosis and metastasis.

Tumor angiogenesis and thymidine phosphorylase expression in ovarian carcinomas including serous surface papillary adenocarcinoma of the peritoneum

To clarify biological and clinical significance of tumor angiogenesis in the development of ovarian carcinoma, we investigated the relationship between tumor vascularity, the expression of thymidine phosphorylase (dThdPase), which is an angiogenic factor identical to platelet-derived endothelial cell growth factor (PD-ECGF), and patient outcome in ovarian carcinoma, including serous surface papillary carcinoma (SSPC). Primary tumor specimens (stages I-IV) from 54 patients were examined. Intratumoral microvessel density (IMVD) and dThdPase expression were evaluated immunohistochemically using anti-CD34 and anti-dThdPase antibodies, and results were correlated with clinicopathologic parameters and prognosis. IMVD for the 54 tumors ranged from 22.5 to 120.7 (number/0.73686 mm2/field). Twenty-three tumors were positive, and 31 tumors were negative for dThdPase expression. IMVD positively correlated with the expression of dThdPase (p < 0.01), tumor size, and peritoneal metastases (p < 0.05). However, there was no statistical correlation between IMVD, dThdPase expression, and clinical outcome. Of the 54 patients examined, 30 were diagnosed with International Federation of Gynecology and Obstetrics (FIGO) stage III or IV primary ovarian carcinoma, and 9 were diagnosed with SSPC. There were no significant differences between the two groups with respect to clinicopathologic features, IMVD, dThdPase expression, or patient outcome. In conclusion, angiogenic activity may be necessary for the growth of metastatic implants in ovarian carcinoma and SSPC.

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.

Tumour vasculature as a target for anticancer therapy

The development of a blood supply is crucial to the growth and metastasis of cancer. The factors involved in this are complex, however tumour hypoxia and macrophage infiltration are responsible for the synthesis of pro-angiogenic cytokines such as vascular endothelial growth factor (VEGF) and the fibroblast growth factors. These factors stimulate proliferation of vascular endothelial cells, the synthesis of proteases such as urokinase type plasminogen activator (uPA) and the matrix metalloproteases, which result in digestion of the extracellular matrix and allow endothelial cell invasion. Endothelial cell motility is promoted by binding of extracellular matrix proteins such as vitronectin and fibronectin to integrins expressed on the plasma membrane of endothelial cells. Interfering with any of these steps may inhibit the process of angiogenesis and drugs aimed at modulation of angiogenesis are currently undergoing evaluation in early clinical studies. This paper reviews our current understanding of angiogenesis and how it may be used as a target for the treatment of cancer.

The significance of thymidine phosphorylase activity in hepatocellular carcinoma and chronic diseased livers: a special reference to liver fibrosis and multicentric tumor occurrence

The role of thymidine phosphorylase (TP), an angiogenic factor, in hepatocellular carcinoma (HCC) remains unclear. The aim of this study was to clarify the significance of TP in HCC. Thirty-seven patients with HCC, who underwent hepatectomy, were included. The TP activity in both cancerous and non-cancerous parts of livers were measured by an enzyme-linked immunosorbent assay. Another 11 patients without HCC were used to evaluate the TP activity in the non-cancerous parts of livers. Both the cancerous and non-cancerous TP activities were clinico-pathologically investigated with special reference to the multicentric occurrence of HCCs and the degree of liver fibrosis; consisting of normal, fibrosis and cirrhosis. The TP activity in the cancerous part was 94.6 +/- 70.2 U/mg protein, while that in non-cancerous parts of the liver was 80.9 +/- 48.8 U/mg protein. No significant difference was observed. The TP activity in the cancerous part did not correlate with any clinicopathological variables, such as tumor differentiation, portal vein invasion, intrahepatic metastases and prognosis. However, the TP activity in the non-cancerous parts of the liver correlated with the degree of fibrosis (normal/fibrosis/cirrhosis = 34:74:90 U/ mg protein, respectively). Furthermore, regarding the correlation between TP activity in the non-cancerous parts and the simultaneously multicentric occurrence of HCC, the TP activity in the multicentric group (n = 8; 121 U/mg protein) was significantly higher than that in the non-multicentric group (n = 29; 70 U/mg protein). The TP activity in the non-cancerous parts increased in proportion to the degree of liver fibrosis. Furthermore, it is suggested that the higher TP activity in the non-cancerous part is related to the multicentric occurrence of HCCs.

Expression of platelet-derived endothelial cell growth factor/thymidine phosphorylase in human gallbladder lesions

The aim of this study was to investigate the expression of platelet-derived endothelial growth factor (PD-ECGF) in human gallbladder carcinomas to elucidate its role in angiogenesis and tumour progression. To this end, 56 archival surgical specimens of gallbladder lesions were examined for PD-ECGF/thymidine phosphorylase (TP) expression by immunohistochemistry and the PD-ECGF/TP protein level was assessed in five fresh specimens of gallbladder carcinoma by enzyme-linked immunosorbent assay (ELISA). Hyperplastic epithelial cells and adenoma cells showed no or faint staining with PD-ECGF/TP. Out of 43 gallbladder carcinomas, 27 (63%) showed moderate to strong immunoreactivity in the cytoplasm and nuclei of the tumour cells. PD-ECGF/TP immunoreactivity in stromal infiltrating cells was detected in 43% (3/7) hyperplasias, 17% (1/6) adenomas and 86% (37/43) carcinomas. PD-ECGF/TP protein levels in carcinoma tissues were higher than those in corresponding normal mucosa. PD-ECGF/TP expression did not correlate with angiogenesis, but significantly correlated with depth of invasion, lymph node metastasis, and tumour stage. These results overall suggest that PD-ECGF/TP produced by both cancer cells and infiltrating cells is associated with tumour progression in human gallbladder carcinoma.

Correlation between tumor angiogenesis and expression of thymidine phosphorylase, and patient outcome in uterine cervical carcinoma

The relationship between tumor angiogenesis and the expression of thymidine phosphorylase (dThdPase) in uterine cervical carcinoma tissues, as well as patient outcome, were investigated. Primary tumor specimens surgically obtained from 54 patients (stages Ib to IIIb) receiving neither chemotherapy nor radiation therapy before surgery were examined. Intratumoral microvessel density (IMVD) and dThdPase expression were evaluated immunohistochemically using anti-CD34 and anti-dThdPase antibodies and were correlated with clinicopathologic parameters and prognosis. IMVD for the 54 tumors ranged from 24.8 to 118.6, with a median value of 57.7 (number/0.7386 mm2/field). For immunoreactivity of dThdPase, 16 tumors were graded as -, 20 as 1+, and 18 as 2+. IMVD was significantly associated with the expression of dThdPase (P<.01). Both IMVD and dThdPase expression were well correlated with depth of myometrial invasion, endometrial invasion, and pelvic lymphnode metastasis (P<.05). Overall survival rates for 18 patients with strong dThdPase-staining tumors, assessed as 2+, were lower than those for 36 with weak dThdPase staining tumors (P = .0108). However, there was no statistical correlation between IMVD and patient outcome. The expression of dThdPase plays a role in the promotion of angiogenesis and affects the patient's survival in uterine cervical carcinomas.

Expression of pyrimidine nucleoside phosphorylase mRNA plays an important role in the prognosis of patients with oesophageal cancer

To clarify the significance of the expression of pyrimidine nucleoside phosphorylase (PyNPase) mRNA as a predictive factor for the prognosis of patients with oesophageal carcinoma, the PyNPase mRNA in the tumours and normal tissues from 55 resected cases of oesophageal carcinoma was examined by a reverse transcription polymerase chain reaction (RT-PCR). As a result, a positive correlation was observed between the tumour/normal (T/N) ratio of the expression of PyNPase mRNA by RT-PCR and that of the enzyme activity of PyNPase based on the findings of an enzyme linked immunosolvent assay (r = 0.594, P = 0.009). The T/N ratio of the expression of PyNPase mRNA was significantly higher in the cases with lymph vessel invasion (P = 0.013), lymph node metastasis (P = 0.0016), and an advanced stage of the disease (P = 0.021) than those without these factors. The patients with a higher T/N ratio of PyNPase mRNA showed significantly worse prognosis than those with a lower T/N ratio (P = 0.023 with log-rank tests). A multivariate analysis for the cumulative survival rates revealed that a high T/N ratio of the expression of PyNPase mRNA was independently related to a poor prognosis. These findings suggested that the determination of PyNPase mRNA by RT-PCR thus appears to be a new useful parameter for identifying both a poor prognosis and a highly malignant potential of oesophageal carcinoma.

Platelet-derived endothelial cell growth factor/thymidine phosphorylase expression correlated with tumor angiogenesis and macrophage infiltration in colorectal cancer

To clarify whether platelet-derived endothelial cell growth factor/thymidine phosphorylase (PD-ECGF/TP) expression in both tumor cells and stromal cells has independent or synergistic effects on tumor angiogenesis and progression and to explore a possible regulator for PD-ECGF/TP expression, immunohistochemical staining was conducted on 148 specimens of colorectal cancer. The microvessel count was significantly correlated with the extent of PD-ECGF/TP expression. Macrophage infiltration in tumors with positive TP was significantly higher than in tumors with negative TP (P < 0.001). The Cox model showed that PD-ECGF/TP expression was an independent prognostic factor, although the microvessel count had a stronger value in determining the patient prognosis.

Association of vascular endothelial growth factor expression with tumor angiogenesis, survival and thymidine phosphorylase/platelet-derived endothelial cell growth factor expression in human colorectal cancer

To examine the association of vascular endothelial growth factor (VEGF) expression with tumor angiogenesis, survival and thymidine phosphorylase/platelet-derived endothelial cell growth factor (dThdPase/PD-ECGF) expression in human colorectal cancer, immunohistochemical studies were performed on 136 cases of resected colorectal cancer specimens using antibodies for VEGF, KDR, CD34 and dThdPase/PD-ECGF. Fifty-nine cases (43%) were evaluated as positive for VEGF staining and 71 cases (52%) were evaluated as positive for dThdPase/PD-ECGF staining. The expression of VEGF correlated significantly with vessel counts and the expression of dThdPase/PD-ECGF (P = 0.01 and 0.01, respectively). Cox proportional hazards model analysis showed that vessel counts and VEGF expression were significant and independent prognostic factors, but that KDR expression was not.

Tumor cell motility and metastasis : Autocrine motility factor as an example of ecto/exoenzyme cytokines

Cellular locomotion plays a critical role in such normal processes as embryonic development, tissue segregation, as well as the infiltration of fibroblasts and vascular cells during wound repair and the inflammatory responses of the adult immune system. During tumor invasion and metastasis the processes of cell migration achieve dire significance. Disruption of normal homeostatic mechanisms to benefit the survival of the individual tumor cell is a common theme discovered during the characterization of factors once thought to be tumor-specific. One such molecule, tumor cell autocrine motility factor, was so described and has only recently been identified as a normal protein involved in intracellular glycolysis as well as implicated as an extracellular effector of normal cell functions including survival of certain populations of neurons. This molecule represents a member of the newly emerging family of intracellular enzymes whose disparate functions as extracellular mediators of cellular responses defines a new class of ecto/exoenzymes which play a role in normal cellular processes and are inappropriately utilized by tumor cells to elicit new survival strategies.