Plasma insulin-like peptide 3 concentrations are acutely regulated by luteinizing hormone in pubertal Japanese Black beef bulls.

Insulin-like peptide 3 (INSL3) is a major secretory product of testicular Leydig cells. The mechanism of acute regulation of INSL3 secretion is still unknown. The present study was undertaken in pubertal beef bulls to (1) determine the temporal relationship of pulsatile secretion among LH, INSL3, and testosterone and (2) monitor acute regulation of INSL3 secretion by LH using GnRH analogue and hCG. Blood samples were collected from Japanese Black beef bulls (N = 6) at 15-minute intervals for 8 hours. Moreover, blood samples were collected at -0.5, 0, 1, 2, 3, 4, 5, and 6 hours after GnRH treatment and -0.5, 0, 2, 4, and 8 hours on the day of treatment (Day 0), and Days 1, 2, 4, 8, and 12 after hCG treatment. Concentrations of LH, INSL3, and testosterone determined by EIAs indicated that secretion in the general circulation was pulsatile. The frequency of LH, INSL3, and testosterone pulses was 4.7 ± 0.9, 3.8 ± 0.2, and 1.0 ± 0.0, respectively, during the 8-hour period. Seventy percent of these INSL3 pulses peaked within 1 hour after a peak of an LH pulse had occurred. The mean increase (peak per basal concentration) of testosterone pulses was higher (P < 0.001) than that of INSL3 pulses. After GnRH treatment, LH concentrations increased (P < 0.01) dramatically 1 hour after treatment and remained high (P < 0.05) until the end of sampling, whereas an elevated (P < 0.05) INSL3 concentration occurred at 1, 2, 5, and 6 hours after treatment. Testosterone concentrations increased (P < 0.01) 1 hour after the treatment and remained high until the end of sampling. After hCG treatment, an increase of INSL3 concentration occurred at 2 and 4 hours, and Days 2, 4, and 8 after treatment (P < 0.05), whereas in case of testosterone, concentrations remained high (P < 0.01) until Day 8 after treatment. The increase (maximum per pretreatment concentration) of INSL3 concentrations after injecting GnRH or hCG was much lower (P < 0.001) than that of testosterone. In conclusion, secretion of INSL3 in blood of bulls occurred in a pulsatile manner. We inferred an acute regulation of INSL3 by LH in bulls because INSL3 concentrations increased immediately after endogenous and exogenous LH stimulation. The increase of INSL3 concentrations by LH was much lower than that of testosterone in bulls.

Endocardial Invasion of Lung Cancer Undiagnosable before Autopsy.

A 59-year-old male patient presented with left chest discomfort on admission. His medical history included encephalitis in childhood and his smoking history was 20 cigarettes per day for 40 years. A physical examination showed an anemic and edematous face with weak respiratory sounds in the left lung. The patient had elevated calcium levels and decreased hemoglobin and potassium. His parathyroid hormone-related protein level was elevated. Thoracic radiography showed cardiomegaly and computed tomography revealed a left lung mass with invasion of the heart and pleural effusion. Magnetic resonance imaging showed endocardial invasion of the tumor mass. Gallium-68 imaging revealed positive accumulation in the region surrounding the heart. No diagnoses were possible upon frequent cytology of his sputum and pleural effusion. The patient died from congestive heart failure with anoxia 38 days after admission. An autopsy revealed tumoral mass occlusion in the left main bronchus and tumoral invasion of the left atrium, left ventricle, and aorta.

PBSC collection from family donors in Japan: a prospective survey.

Severe adverse events (SAE) and late hematological malignancies have been reported after PBSC donation. No prospective data on incidence and risk factors have been available for family donors so far. The Japan Society for Hematopoietic Cell Transplantation (JSHCT) introduced therefore in 2000 a mandatory registration system. It defined standards for donor eligibility and asked harvest centers to report any SAE immediately. All donors were examined at day 30 and were to be contacted once each year for a period of 5 years. Acute SAEs within day 30 were reported from 47/3264 donations (1.44%) with 14 events considered as unexpected and severe (0.58%). No donor died within 30 days. Late SAEs were reported from 39/1708 donors (2.3%). The incidence of acute SAEs was significantly higher among donors not matching the JSHCT standards (P=0.0023). Late hematological malignancies in PBSC donors were not different compared with a retrospective cohort of BM donors (N:1/1708 vs N:2/5921; P=0.53). In conclusion, acute and late SAEs do occur in PBSC donors at relatively low frequency but risk factors can be defined.

A peptide microarray fabricated on a non-fouling phosphatidylcholine-polymer-coated surface for a high-fidelity analysis of a cellular kinome.

Phosphatidylcholine-polymer-coated plastic slides were utilized for the fabrication of peptide microarrays for cellular kinome analysis. According to the non-fouling features of the surface, the signal-to-noise ratio of the detection of phosphorylated peptides improved by about 100-fold from that of a peptide microarray fabricated on a glass slide blocked by a commercial BSA-based reagent. When the phosphatidylcholine-polymer-coated peptide microarray was applied to the analysis of the kinome of HCC827 cells, hyperactivation of c-Src and EGFR were successfully detected.

Spontaneous remission of epstein-barr virus-positive diffuse large B-cell lymphoma of the elderly.

A 94-year-old female patient presented with anorexia and left axillar lymphadenopathy on admission. Her past history was angina pectoris at 83 years of age and total gastrectomy due to gastric cancer at 87 years. The family history revealed that her son had had a malignant lymphoma, the histopathological diagnosis of which was diffuse large B-cell lymphoma. A physical examination showed both cervical, axillar, and inguinal lymphadenopathy without tenderness. She had elevated lactate dehydrogenase, ferritin, and soluble interleukin-2 receptor (sIL-2R). Whole-body computed tomography confirmed the cervical, axillary, and inguinal lymphadenopathy. Gallium-68 imaging revealed positive accumulation in these superficial lymph nodes. A right inguinal lymph node biopsy showed features of Epstein-Barr virus-associated lymphoproliferative disorder. Immunohistological studies on this lymph node biopsy showed CD20-positive large cells, CD3-positive small cells, and CD30-partly-positive large cells. In situ hybridization showed Epstein-Barr virus-positive, LMP-partly-positive, and EBNA2-negative cells. She refused chemotherapy as her son had died from hematemesis during chemotherapy. She received intravenous hyperalimentation for 1 month after admission. No palpable lymph nodes were identified by physical examination or computed tomography 3 months after admission, and regression of lactate dehydrogenase, ferritin, and sIL-2R was observed. She recovered from anorexia and was discharged. She died from pneumonia 10 months later after initial symptoms of anorexia. The autopsy showed no superficial lymphadenopathy.

The combination of hyperthermia or chemotherapy with gimeracil for effective radiosensitization.

PURPOSE: 5-chloro-2,4-dihydroxypyridine (gimeracil) is a component of the oral fluoropyrimidine derivative S-1. Gimeracil was originally added to S-1 to yield prolonged 5-fluorouracil (5-FU) concentrations in serum and tumor tissues by inhibiting dihydropyrimidine dehydrogenase, which degrades 5-FU. We previously demonstrated that gimeracil enhances the efficacy of radiotherapy through the suppression of homologous recombination (HR) in DNA double strand repair. The goal of this paper was to examine the effects of gimeracil on the sensitivity of anticancer drugs and hyperthermia in order to obtain effective radiosensitization. MATERIALS AND METHODS: Various cell lines, including DLD 1 (human colon carcinoma cells) and cells deficient in HR or nonhomologous end-joining (NHEJ), were used in clonogenic assays. The survival of these cells after various treatments (e.g., drug treatment, heat treatment, and radiation) was determined based on their colony-forming ability. RESULTS: Gimeracil enhanced cell-killing effects of camptothecin (CPT), 5-FU, and hydroxyurea. Gimeracil sensitized effects of CPT or 5-FU to cells deficient in HR or NHEJ to a similar extent as in other cells (DLD1 and a parent cell), indicating that its sensitizing mechanisms may be different from inhibition of HR or NHEJ. Combination of gimeracil and CPT or 5-FU sensitized radiation more effectively than each modality alone. Gimeracil also enhanced heat sensitivity at 42°C or more. The degree of heat sensitization with gimeracil increased as the temperature increased, and the combination of gimeracil and heat-sensitized radiation was more effective than each modality alone. CONCLUSION: Gimeracil enhanced sensitivity of CPT, 5-FU, and hyperthermia. Combination of these modalities sensitized radiation more efficiently than each modality alone.

Degree of freezing does not affect efficacy of frozen gloves for prevention of docetaxel-induced nail toxicity in breast cancer patients.

PURPOSE: Frozen gloves (FG) are effective in preventing docetaxel-induced nail toxicity (DNT), but uncomfortable. The preventive effect of FG for DNT was compared using a standard (-25 to -30°C) or more comfortable (-10 to -20°C) preparation. METHODS: Breast cancer patients receiving docetaxel were eligible. Each patient wore an FG (prepared at -10 to -20°C for 90 min) for 60 min without replacement on the right hand. The left hand was protected by standard methods (FG prepared at -25 to -30°C overnight and worn for 90 min with replacement at 45 min). The primary endpoint was DNT occurrence at 5 months. Secondary endpoints included docetaxel exposure [cumulative dose and area under the blood concentration time curve (AUC)] until DNT occurrence and discomfort from FG. The pharmacokinetics of docetaxel was assessed. RESULTS: From 23 patients enrolled between December 2006 and June 2010, seven who received docetaxel for less than 5 months were excluded from evaluation. The median accumulated docetaxel dose was 700 mg/m(2) (340-1430 mg/m(2)). Within 5 months of FG use, none developed protocol-defined DNT in either hand. Two patients (13%) developed DNT at 7.2 and 7.3 months, respectively, both at -10 to -20°C. In the control hand (-25 to -30°C), discomfort occurred in 92% of the cycles, compared to 15% in the experimental hand (-10 to -20°C). Five patients (22%) experienced pain at -25 to -30°C, but none did at -10 to -20°C. The degree of docetaxel exposure was not related to DNT occurrence in our study. CONCLUSION: A convenient preparation of FG at -10 to -20°C is almost as effective as a standard preparation at -25 to -30°C, with significantly less discomfort.

Thymidine phosphorylase in cancer cells stimulates human endothelial cell migration and invasion by the secretion of angiogenic factors.

BACKGROUND: Thymidine phosphorylase (TP) is often overexpressed in tumours and has a role in tumour aggressiveness and angiogenesis. Here, we determined whether TP increased tumour invasion and whether TP-expressing cancer cells stimulated angiogenesis. METHODS: Angiogenesis was studied by exposing endothelial cells (HUVECs) to conditioned medium (CM) derived from cancer cells with high (Colo320TP1=CT-CM, RT112/TP=RT-CM) and no TP expression after which migration (wound-healing-assay) and invasion (transwell-assay) were determined. The involvement of several angiogenic factors were examined by RT-PCR, ELISA and blocking antibodies. RESULTS: Tumour invasion was not dependent on intrinsic TP expression. The CT-CM and RT-CM stimulated HUVEC-migration and invasion by about 15 and 40%, respectively. Inhibition by 10 µM TPI and 100 µM L-dR, blocked migration and reduced the invasion by 50-70%. Thymidine phosphorylase activity in HUVECs was increased by CT-CM. Reverse transcription-polymerase chain reaction revealed a higher mRNA expression of bFGF (Colo320TP1), IL-8 (RT112/TP) and TNF-α, but not VEGF. Blocking antibodies targeting these factors decreased the migration and invasion that was induced by the CT-CM and RT-CM, except for IL-8 in CT-CM and bFGF in RT-CM. CONCLUSION: In our cell line panels, TP did not increase the tumour invasion, but stimulated the migration and invasion of HUVECs by two different mechanisms. Hence, TP targeting seems to provide a potential additional strategy in the field of anti-angiogenic therapy.

Thymidylate synthase (TS) gene expression in primary lung cancer patients: a large-scale study in Japanese population.

BACKGROUND: Previous small-sized studies showed lower thymidylate synthase (TS) expression in adenocarcinoma of the lung, which may explain higher antitumor activity of TS-inhibiting agents such as pemetrexed. PATIENTS AND METHODS: To quantitatively measure TS gene expression in a large-scale Japanese population (n = 2621) with primary lung cancer, laser-captured microdissected sections were cut from primary tumors, surrounding normal lung tissues and involved nodes. RESULTS: TS gene expression level in primary tumor was significantly higher than that in normal lung tissue (mean TS/ß-actin, 3.4 and 1.0, respectively; P < 0.01), and TS gene expression level was further higher in involved node (mean TS/ß-actin, 7.7; P < 0.01). Analyses of TS gene expression levels in primary tumor according to histologic cell type revealed that small-cell carcinoma showed highest TS expression (mean TS/ß-actin, 13.8) and that squamous cell carcinoma showed higher TS expression as compared with adenocarcinoma (mean TS/ß-actin, 4.3 and 2.3, respectively; P < 0.01); TS gene expression was significantly increased along with a decrease in the grade of tumor cell differentiation. There was no significant difference in TS gene expression according to any other patient characteristics including tumor progression. CONCLUSION: Lower TS expression in adenocarcinoma of the lung was confirmed in a large-scale study.

Bone marrow mononuclear cells versus G-CSF-mobilized peripheral blood mononuclear cells for treatment of lower limb ASO: pooled analysis for long-term prognosis.

In this study, we report the comparative result of long-term clinical prognoses for patients with no-option critical limb ischemia (CLI) caused by arteriosclerosis obliterans, who are implanted with autologous bone marrow mononuclear cells (BMMNC; n=74) or G-CSF-mobilized (M)-PBMNC (n=111), as no information is available on how the two treatments compare in terms of long-term prognosis, such as survival or amputation. We performed pooled analysis using data from two previous cohort studies. All patients had disease of Fontaine classification III or IV. The endpoints were OS and amputation-free survival (AFS). After adjustment for history of dialysis and Fontaine classification, there was no significant difference between the two treatments with respect to OS (hazard ratio (HR)=1.49; 95% confidence interval (CI)=0.74-3.03, P=0.26) or AFS (HR=0.96; 95% CI=0.61-1.51, P=0.87). The negative prognostic factors affecting OS or AFS were the small number of CD34-positive cells collected, history of dialysis, Fontaine classification, male sex and older age. These results suggest that there was no significant difference in long-term prognosis between patients treated with BMMNC and those treated with M-PBMNC. The number of CD34-positive cells collected was an important prognostic factor for amputation and death.

Increased migration by stimulation of thymidine phosphorylase in endothelial cells of different origin.

Thymidine phosphorylase (TP) catalyzes the phosphorylytic cleavage of thymidine to thymine and deoxyribose-1-phosphate. The latter may be involved in the angiogenic stimulation of TP. In the present study, we investigated whether thymidine and deoxyribose (dR) could stimulate angiogenesis in vitro of two types of endothelial cells (isolated from umbilical veins (HUVEC) and endothelial colony forming cells (ECFC)), and whether the stereoisomer L-deoxyribose (L-dR) and the thymidine phosphorylase inhibitor (TPI) could reduce this. Both cell types had a low TP activity. Thymidine increased the migration of both HUVECs and ECFCs, but dR only that of the ECFCs. The invasion was not changed by any of the agents tested. In conclusion, TP may play a role in the migration of HUVECs and ECFCs, but not the invasion.

Accumulation of thymidine-derived sugars in thymidine phosphorylase overexpressing cells.

Thymidine phosphorylase (TP) is often overexpressed in cancer and potentially plays a role in the stimulation of angiogenesis. The exact mechanism of angiogenesis induction is unclear, but is postulated to be related to thymidine-derived sugars. TP catalyzes the conversion of thymidine (TdR) to thymine and deoxyribose-1-phosphate (dR-1-P), which can be converted to dR-5-P, glyceraldehyde-3-phosphate (G3P) or deoxyribose (dR). However, it is unclear which sugar accumulates in this reaction. Therefore, in the TP overexpressing Colo320 TP1 and RT112/TP cells we determined by LC-MS/MS which sugars accumulated, their subcellular localization (using (3)H-TdR) and whether dR was secreted from the cells. In both TP-overexpressing cell lines, dR-1-P and dR-5-P accumulated intracellularly at high levels and dR was secreted extensively by the cells. A specific inhibitor of TP completely blocked TdR conversion, and thus no sugars were formed. To examine whether these sugars may be used for the production of angiogenic factors or other products, we determined with (3)H-TdR in which subcellular location these sugars accumulated. TdR-derived sugars accumulated in the cytoskeleton and to some extent in the cell membrane, while incorporation into the DNA was responsible for trapping in the nucleus. In conclusion, various metabolic routes were entered, of which the TdR-derived sugars accumulated in the cytoskeleton and membrane. Future studies should focus on which exact metabolic pathway is involved in the induction of angiogenesis.

Chemotherapy-induced neutropenia as a prognostic factor in advanced non-small-cell lung cancer: results from Japan Multinational Trial Organization LC00-03.

BACKGROUND: Neutropenia is a common adverse reaction of chemotherapy. We assessed whether chemotherapy-induced neutropenia could be a predictor of survival for patients with non-small-cell lung cancer (NSCLC). METHODS: A total of 387 chemotherapy-naïve patients who received chemotherapy (vinorelbine and gemcitabine followed by docetaxel, or paclitaxel and carboplatin) in a randomised controlled trial were evaluated. The proportional-hazards regression model was used to examine the effects of chemotherapy-induced neutropenia and tumour response on overall survival. Landmark analysis was used to lessen the bias of more severe neutropenia resulting from more treatment cycles allowed by longer survival, whereby patients who died within 126 days of starting chemotherapy were excluded. RESULTS: The adjusted hazard ratios for patients with grade-1 to 2 neutropenia or grade-3 to 4 neutropenia compared with no neutropenia were 0.59 (95% confidence interval (CI), 0.36-0.97) and 0.71 (95% CI, 0.49-1.03), respectively. The hazard ratios did not differ significantly between the patients who developed neutropenia with stable disease (SD), and those who lacked neutropenia with partial response (PR). CONCLUSION: Chemotherapy-induced neutropenia is a predictor of better survival for patients with advanced NSCLC. Prospective randomised trials of early-dose increases guided by chemotherapy-induced toxicities are warranted.

Macular hole formation after macular haemorrhage associated with rupture of retinal arterial macroaneurysm.

AIM: To investigate the frequency and risk factors of macular hole (MH) formation after rupture of a retinal arterial macroaneurysm. METHODS: Fifty-six eyes from 56 patients with rupture of a retinal arterial macroaneurysm with or without an MH (MH and non-MH groups, respectively) were reviewed. Frequency and risk factors related to MH formation were assessed, with risk factors including age; sex; distance from the macroaneurysm to the fovea; incidence of haemorrhages involving the macula such as preretinal, subinternal limiting membrane (sub-ILM), subretinal and vitreous; and vitreous surgery. MH formation in these patients was recorded and analysed. RESULTS: Of the 56 eyes reviewed, seven (12.5%) had an MH after rupture of the retinal arterial macroaneurysm. The incidence of subretinal and sub-ILM haemorrhages involving the macula was significantly greater in the MH group than in the non-MH group (p = 0.037 and 0.045, respectively). CONCLUSION: These results suggest that the presence of subretinal and sub-ILM haemorrhages after rupture of a retinal arterial macroaneurysm may contribute to formation of an MH.

A history of smoking is inversely correlated with the incidence of gemcitabine-induced neutropenia.

BACKGROUND: Smoking may affect the efficacy of chemotherapy and the incidence of adverse events. We investigated the correlation between smoking history and gemcitabine-induced neutropenia. PATIENTS AND METHODS: Data on smoking history and incidence of grade 3-4 neutropenia were retrospectively gathered for 103 chemo-naive patients treated with gemcitabine monotherapy (59 patients with pancreatic, 41 with hepatobiliary and three with other cancers). RESULTS: There was a significantly higher incidence of grade 3-4 neutropenia among patients without a history of smoking (55.7%) than among those with a history of smoking (including current and ex-smokers; 23.6%) [odds ratio (OR) 0.244, 95% confidence interval (CI) 0.105-0.569; P < 0.001]. After adjustment for age, gender, platelet and baseline neutrophil counts, history of surgery for primary cancer, creatinine concentration, hemoglobin concentration, aspartate aminotransferase concentration, alanine aminotransferase concentration and total bilirubin concentration, logistic regression analysis identified a history of smoking as an independent inverse predictor of gemcitabine-induced neutropenia (OR 0.188, 95% CI 0.057-0.618; P = 0.006). CONCLUSION: Patients without a history of smoking may be at higher risk of developing gemcitabine-induced neutropenia. The mechanism underlying this phenomenon is unclear at this point.

Synergistic interaction between trifluorothymidine and docetaxel is sequence dependent.

Docetaxel is a microtubule inhibitor that has actions in the S and G(2)-M phase of the cell cycle. The pyrimidine trifluorothymidine (TFT) induces DNA damage and an arrest in the G(2)-M phase. TFT, as part of TAS-102, has been clinically evaluated as an oral chemotherapeutic agent in colon and gastric cancer. The aim of the present study was to determine the optimal administration sequence of TFT and docetaxel and to investigate the underlying mechanism of cytotoxicity. Drug interactions were examined by sulforhodamine B assays and subsequent combination index analyses, and for long-term effects the clonogenic assay was used. A preincubation with docetaxel was synergistic in sulforhodamine B (combination index 0.6-0.8) and clonogenic assays, and was accompanied by a time-dependent cell death induction (17-36%), the occurrence of polynucleation (22%), and mitotic spindle inhibition as determined by flow cytometry and immunostaining. Interestingly, administration of TFT followed by the combination displayed strong antagonistic activity, and was accompanied by less polynucleation and cell death induction than the synergistic combinations. Western blotting showed that the G(2)-M-phase arrest (25-50%) was accompanied by phosphorylation of Chk2 and dephosphorylation of cdc25c in the synergistic combinations. Together, this indicates that synergistic activity requires docetaxel to initiate mitotic failure prior to the activation of TFT damage signaling, whereas antagonism is a result of TFT cell cycle-arrested cells being less susceptible to docetaxel. Caspase 3 activation was low after docetaxel, suggestive of caspase-independent mechanisms of cell death. Taken together, our models indicate that combination treatment with docetaxel and TFT displays strong synergy when docetaxel is given first, thus providing clues for possible clinical studies.

Reduced GFR and albuminuria in Chinese type 2 diabetes mellitus patients are both independently associated with activation of the TNF-alpha system.

AIMS/HYPOTHESIS: The involvement of chronic inflammation in albuminuria and renal function was investigated in a cross-sectional study of 320 type 2 diabetic Chinese patients from the Singapore Diabetes Cohort Study. METHODS: Plasma levels of TNF-alpha and its two cellular receptors and of IL-6 and C-reactive protein (CRP) were measured. A composite TNF-alpha score was extracted using principal component analysis. Multiple linear regression analysis was implemented to evaluate the relationship between log( e ) (ln) albumin:creatinine ratio (ACR) and estimated GFR (eGFR) with the inflammatory variables and other clinical covariates. A Bonferroni correction was applied based on the total number of variables entered into regression analyses. RESULTS: ln ACR was significantly associated with TNF-alpha score independently of eGFR even after a Bonferroni correction. TNF-alpha score was also significantly associated with eGFR independently of ln ACR even after correction for multiple testing. These findings were similar when the individual molecules of the TNF-alpha system were analysed separately instead of using the composite TNF-alpha score. No association was observed for IL-6 and CRP with either renal trait. Diabetes duration was a significant predictor for ln ACR but not eGFR. Conversely, age was significantly associated with eGFR but not ln ACR. CONCLUSIONS/INTERPRETATION: Activation of the TNF-alpha system may potentially exert independent effects on ln ACR and eGFR in type 2 diabetes. Because of the study design, one may also consider the possibility that changes in these renal traits may conversely be responsible for such an inflammatory response.

Thymidine phoshorylase as a target for antiangiogenesis treatment.

Thymidine phosphorylase (TP) has emerged as a promising target for antiangiogenesis treatment of cancer. Angiogenesis, the formation of blood vessels, is essential for tumors to grow in order to be supplied with nutrients and oxygen. The association of TP with angiogenesis was demonstrated in several clinical studies in various tissue types. It has been postulated that the angiogenic effect of TP is related to its enzymatic activity, which catalyzes the breakdown of thymidine to thymine and deoxyribose-1-phosphate (dR-1-P). The latter, in its parent form or in its sugar form, deoxyribose, may play a role in angiogenesis. It may interfere in cellular energy metabolism or be substrate in a chemical reaction generating reactive oxygen species. L-deoxyribose and a specific TP inhibitor, TPI, can reverse these effects, supporting the role of the enzymatic reaction and that of the sugar. Although TP is usually high in the tumor, we also observed a high expression in tumor-associated stromal cells and macrophages. In order to elucidate the mechanism of TP induced angiogenesis we have investigated the association of TP with angiogenesis, the effect of thymidine and its metabolites on angiogenic parameters (e.g. invasion), the modulation by TPI, the formation and retention of the sugar metabolites of thymidine, and the potential signalling pathways involved in the angiogenic process. We used cell lines without/low TP expression (Colo320 and RT112) and TP transfected variants (Colo320TP1 and RT112/TP). Intrinsic TP expression in cancer cells did not stimulate these cells to invade more. On the other hand, Colo320 and Colo320TP1 cells could attract endothelial cells to a high extent, but Colo320TP1 did not attract them to a higher extent. RT112/TP cells attracted more endothelial cells than RT112 (2 fold). The difference between the RT112's and Colo320's may be related to different formation of sugars. Exposure of tumor cells to thymidine resulted in a rapid formation of dR-1-P, which was rapidly degraded to deoxyribose and further metabolized to other sugar derivatives. Of the possible sugars that can be produced by the conversion of TdR, dR-5-P seems to accumulate the most. dR accumulated 3 fold higher extent in RT112/TP than in Colo320/TP1 cells. dR could be converted to advanced glycation endproducts (AGE), however this was to a lower extent than ribose. Thymidine also induced several signalling pathways in the cells, involved in migration and invasion, such as the Focal adhesion kinase (FAK), which subsequently stimulated p70/S6 phosphorylation. The latter is a downstream kinase of rapamycin and its phosphorylation is inhibited by rapamycin, an mTOR inhibitor. The association between rapamycin and TP was shown by the protection by thymidine of rapamycin induced cytotoxicity, while TPI inhibited the effect of thymidine addition. These studies clearly show a mechanistic link between TP, signalling pathways, and cell migration.

The role of platelet-derived endothelial cell growth factor/thymidine phosphorylase in tumor behavior.

Platelet-derived endothelial cell growth-factor (PD-ECGF) is similar to the pyrimidine enzyme thymidine phosphorylase (TP). A high TP expression at tumor sites is correlated with tumor growth, induction of angiogenesis, and metastasis. Therefore, high TP is most likely associated with a poor prognosis. TP is not only expressed in tumor cells but also in tumor surrounding tissues, such as tumor infiltrating macrophages. TP catalyzes the conversion of thymidine to thymine and doxyribose-1-phosphate (dR-1-P). The latter in its parent form or in its sugar form, deoxyribose (dR) may play a role in the induction of angiogenesis. It may modulate cellular energy metabolism or be a substrate in a chemical reaction generating reactive oxygen species. L-deoxyribose (L-dR) and thymidine phosphorylase inhibitor (TPI) can reverse these effects. The mechanism of TP induction is not yet completely clear, but TNF, IL10 and other cytokines have been clearly shown to induce its expression. The various complex interactions of TP give it an essential role in cellular functioning and, hence, it is an ideal target in cancer therapy.