Orotate Phosphoribosyl Transferase mRNA Research Articles

Intratumor dihydropyrimidine dehydrogenase mRNA expression levels are decreased in extramammary Paget's disease.

S-1, a 5-fluorouracil (5-FU)-based anti-cancer agent, is an important drug for treating metastatic extramammary Paget's disease (EMPD). Although intratumor expression levels of 5-FU metabolism enzymes have been studied widely in many solid tumors, no studies have examined on the expression levels of thymidylate synthase (TS), orotate phosphoribosyl-transferase (OPRT) or dihydropyrimidine dehydrogenase (DPD) in skin cancers. The aim of this study was to estimate the intratumoral mRNA expression levels of these genes in EMPD by real time PCR. Intratumoral DPD mRNA levels were decreased in EMPD compared to those in normal skin, but its intratumoral DPD mRNA expression levels were not correlated with clinical manifestations. Intratumoral DPD mRNA levels were positively correlated with OPRT mRNA levels in EMPD. Based on these results, low expression of intratumoral DPD mRNA in EMPD may contribute to the pathogenesis of this disease.

Expression level of dihydropyrimidine dehydrogenase is associated with clinical outcome in patients with T1G3 bladder cancer treated with Bacillus Calmette-Guerin

BackgroundRecently, it has been shown that 5-fluorouracil (5-FU) with a strong dihydropyrimidine dehydrogenase (DPD) inhibitor elicits a significant response in bladder cancer with a high level of DPD. However, only a few studies investigated the association between the level of the enzyme that regulates the metabolism of 5-FU and prognosis in bladder cancer. Furthermore, to our knowledge, there has also been no such report in T1G3 bladder tumors treated with BCG. Therefore, we evaluated enzymes that regulate the metabolism of 5-FU in T1G3 tumors treated with BCG immunotherapy using the Danenberg tumor profile (DTP) method, a highly accurate measurement of RNA from paraffin-embedded specimens.MethodsThis study included 28 patients with T1G3 bladder cancer, each of whom underwent complete transurethral tumor resection and BCG intravesical instillation at our institution. The median follow-up period was 39 months (range, 3 to 159 months). The DTP method was used to analyze the mRNA expression of 3 enzymes related to 5-FU: DPD, orotate phosphoribosyltransferase (OPRT), and thymidylate synthase (TS).ResultsAmong the 28 patients, 13 developed recurrences (46.4%) and 5 experienced disease progression (17.9%). An elevated DPD mRNA level was significantly associated with recurrence (p = 0.048) and progression (p = 0.045). However, TS and OPRT mRNA levels were not significantly associated with any other clinical features or outcomes. Furthermore, the high DPD group had a significantly lower recurrence-free survival rate than the low DPD group (p = 0.047). Among patients with low DPD, the 2- and 5-year recurrence-free survival rates were 88.9% and 74.1%, respectively; while among patients with high DPD, the corresponding rates were 61.3% and 36.8%, respectively. TS and OPRT were not significantly associated with recurrence-free survival rates.ConclusionDPD is significantly associated with recurrence and progression among T1G3 bladder cancer patients treated with BCG.

Effects of smoking and alcohol consumption on 5-fluorouracil-related metabolic enzymes in oral squamous cell carcinoma.

Lifestyle, particularly smoking and alcohol consumption, may induce and/or inhibit drug metabolism. In order to reveal the effects of smoking and alcohol consumption on the 5-fluorouracil (5-FU)-related metabolic enzymes, namely thymidylate synthase, dihydropyrimidine dehydrogenase (DPD; a sole catabolic enzyme of 5-FU), orotate phosphoribosyl transferase (OPRT) and thymidine phosphorylase, in oral squamous cell carcinomas, the mRNA expression of these enzymes was investigated in 29 surgical specimens and compared by the Brinkman index and drinking years. The surgical specimens were divided into normal and tumor regions and were independently analyzed using quantitative reverse transcription-polymerase chain reaction. There was a significantly positive correlation between DPD mRNA expression in these tissues and Brinkman index/drinking years, with OPRT mRNA expression being significantly correlated to the Brinkman index in tumor tissues. These results revealed that lifestyle habits, including smoking and alcohol consumption, may vary the activity of the 5-FU-related metabolic enzymes. DPD is the initial and rate-limiting enzyme in the catabolic pathway of 5-FU. Therefore, smoking and alcohol consumption may reduce the anticancer activity of 5-FU, possibly through the induction of DPD activity.

Orotate phosphoribosyl transferase mRNA expression and the response of cholangiocarcinoma to 5-fluorouracil

To determine whether expression of certain enzymes related to 5-fluorouracil (5-FU) metabolism predicts 5-FU chemosensitivity in cholangiocarcinoma (CCA). The histoculture drug response assay (HDRA) was performed using surgically resected CCA tissues. Tumor cell viability was determined morphologically with hematoxylin and eosin- and terminal deoxynucleotide transferase-mediated dUTP nick-end labeling-stained tissues. The mRNA expression of thymidine phosphorylase (TP), orotate phosphoribosyl transferase (OPRT), thymidylate synthase (TS), and dihydropyrimidine dehydrogenase (DPD) was determined with real-time reverse transcriptase-polymerase chain reaction. The levels of gene expression and the sensitivity to 5-FU were evaluated. Twenty-three CCA tissues were obtained from patients who had been diagnosed with intrahepatic CCA and who underwent surgical resection at Srinagarind Hospital, Khon Kaen University from 2007 to 2009. HDRA was used to determine the response of these CCA tissues to 5-FU. Based on the dose-response curve, 200 μg/mL 5-FU was selected as the test concentration. The percentage of inhibition index at the median point was selected as the cut-off point to differentiate the responding and non-responding tumors to 5-FU. When the relationship between TP, OPRT, TS and DPD mRNA expression levels and the sensitivity of CCA tissues to 5-FU was examined, only OPRT mRNA expression was significantly correlated with the response to 5-FU. The mean expression level of OPRT was significantly higher in the responder group compared to the non-responder group (0.41 ± 0.25 vs 0.22 ± 0.12, P < 0.05). OPRT mRNA expression may be a useful predictor of 5-FU chemosensitivity of CCA. Whether OPRT mRNA could be used to predict the success of 5-FU chemotherapy in CCA patients requires confirmation in patients.

Comment on “Influence of Orotate Phosphoribosyl Transferase Levels on Tumor Prognosis and Response to Chemotherapy”

I read with great interest the recent article by Yasumatsu et al. [1]. Interestingly, recent data suggests that orotate phosphoribosyl transferase (OPRT) may significantly influence tumor prognosis and response to 5-fluorouracil therapy in a number of systemic malignancies besides head and neck carcinomas. For instance, a close association exists between OPRT levels and prognosis in esophageal malignancies. Early stages such as stage I and stage II express higher levels of orotate phosphoribosyl transferase (OPRT) in contrast to late stages [2]. Hence, OPRT may significantly influence prognosis in esophageal carcinomas. Similarly, increased chances of metastasis following surgery for colorectal carcinomas is seen in primary tumors that show accentuated OPRT expression. An increased risk of hematogeneous metastasis is seen in colorectal tumors with elevated OPRT levels [3]. Similarly, OPRT expression enhances the antineoplastic effects of 5-fluorouracil in gastric carcinomas and markedly improves prognosis in these patients [4]. Similar, relationships are seen in pancreatic malignancies. For instance, OPRT negative tumors are associated with a lower postsurgical resection survival rates in comparison to OPRT-positive pancreatic malignancies [5]. Patients with OPRT-positive tumors who are administered chemotherapy with chemotherapeutic agents such as gemcitabine have higher survival rates in contrast to those who do not receive similar adjuvant therapy. Similarly, there is upregulation of OPRT expression in prostate malignancies. In fact, a close association is seen between grading and tumor OPRT mRNA expression. In addition, hormone-refractory prostate cancers demonstrate a higher OPRT/dihydropyrimidine dehydrogenase (DPD) ratio in contrast to hormone-sensitive prostate cancer [6, 7]. This higher OPRT/DPD ratio explains the higher sensitivity of these tumors to 5-fluorouracil therapy. Similarly, bladder carcinomas demonstrate increased OPRT activity in contrast to normal bladder tissue. In fact, low-grade bladder carcinomas express lower levels of OPRT in contrast to high-grade bladder carcinomas. OPRT expression significantly influences the sensitivity of the tumors to 5-fluorouracil and this is an important factor in assessing prognosis in bladder carcinomas [7]. The above examples illustrate the close association between OPRT and treatment outcome and response to 5-fluorouracil in systemic malignancies and the need for further studies in this regard.

Thymidylate Synthase, Dihydropyrimidine Dehydrogenase, Thymidine Phosphorylase, Orotate Phosphoribosyltransferase mRNA Expression in Lung Cancer Metastatic Lymph Node Samples Obtained by Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration – A Pilot Study

Introduction/BackgroundPyrimidine antimetabolites' target molecules thymidylate synthase (TS) and flopropyrimidine-metabolising enzymes such as dihydropyrimidine dehydrogenase (DPD), thymidine phosphorylase (TP) and orotate phosphoribosyltransferase (OPRT) are known as biomarkers of 5-fluorouracil (5-FU) treatment. The purpose of this study was to evaluate the feasibility of mRNA expression analysis for TS, DPD, TP, and OPRT using metastatic lymph node samples obtained by endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) in patients with non–small-cell lung cancer (NSCLC). Materials and MethodsMetastatic lymph nodes from 20 patients with NSCLC diagnosed by EBUS-TBNA were analyzed. After pathological diagnosis, additional sections were made and confirmed the existence of tumor cells by hematoxylin and eosin staining. Tumor cells were extracted using laser-captured microdissection and the mRNA levels were measured by quantitative reverse-transcriptase polymerase chain reaction (RT-PCR) for each marker. ResultsThere were 17 mediastinal and 3 hilar lymph nodes. The histology included 13 cases of adenocarcinoma and 7 cases of squamous cell carcinoma. DPD and TP could be successfully analyzed in all samples and TS and OPRT could be measured in 18 samples. The median values of the relative TS, DPD, TP, and OPRT mRNA expression levels were 10.68, 6.23, 18.32, and 1.77, respectively. ConclusionTS, DPD, TP, and OPRT mRNA expression levels could be analyzed using metastatic lymph node samples obtained by EBUS-TBNA. The result of this pilot study may be applicable for further translational research for the treatment of locally advanced NSCLC.

Abstract 5249: Analysis of gene expression levels associating with metabolism of 5-fluorouracil and folate in primary colorectal cancer and corresponding synchronous or metachronous liver metastasis

Abstract Background Gene expression levels of thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD), thymidine phosphorylase (TP) and orotate phosphoribosyl transferase (OPRT) have been shown to be associated with response to 5-fluorouracil-based therapies. Folylpolyglutamate synthase (FPGS), gamma-glutamyl hydrolase (GGH) and dihydrofolate reductase (DHFR) are associated with folate metabolism which regulates intracellular folate level. Analyzing these gene expression levels in liver metastases is important to obtain the prediction of therapy, however, only surgical specimens of the primary tumor are readily available for analysis in many cases. Our aim is to determine how TS, DPD, TP, OPRT, FPGS, GGH and DHFR gene expression levels in primary colorectal cancer (CRC) are related to those in liver metastases. Methods Formalin-fixed, paraffin-embedded tumor specimens from 50 pairs of primary CRC and corresponding liver metastases, including 30 synchronous and 20 metachronous metastases, were dissected by using laser-captured microdissection. Total RNA was extracted and cDNA was prepared by reverse-transcription. Quantitation of target genes and internal reference gene, beta-2-microglobulin, was performed using real-time RT-PCR. Results Significant difference was seen between mRNA expression levels of TS, DPD, FPGS and DHFR in primary tumor and those in corresponding synchronous liver metastases (median value: TS 1.18 vs. 0.05; p&amp;lt;0.0001, DPD 0.18 vs.0.05; p&amp;lt;0.0001, FPGS 0.07 vs. 0.02; p=0.0005, DHFR 0.31 vs. 0.03; p&amp;lt;0.0001), TS, DPD, TP, OPRT, FPGS and DHFR in primary tumor and those in corresponding metachronous liver metastases (TS 0.23 vs. 0.06; p&amp;lt;0.0001, DPD .0.31 vs. 0.03; p&amp;lt;0.0001, TP 0.21 vs. 0.14, p=0.021, OPRT 0.35 vs. 0.17; p=0.016, FPGS 0.11 vs. 0.04; p=0.0003, DHFR 0.41 vs. 0.03, p&amp;lt;0.0001). When matched tissue sets were compared on an individual basis, there was a significant correlation for TP, OPRT and FPGS mRNA expression between primary tumor and corresponding synchronous liver metastases (TP rs=0.64; p=0.018, OPRT rs=0.62; p=0.006, FPGS rs=0.51; p=0.004), DPD and GGH in primary tumor and corresponding metachronous liver metastases (DPD rs=0.54; p=0.014, GGH rs=0.59; p=0.007). Conclusion A good prediction of TP, OPRT and FPGS mRNA levels in synchronous liver metastases as well as DPD and GGH mRNA levels in metachronous liver metastasis can be obtained by measuring those of primary CRC, although no correlation was seen for other genes. We are currently investigating more number of cases and genes related with sensitivity to antitumor drugs. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5249. doi:10.1158/1538-7445.AM2011-5249

Analysis of 5-Fluorouracil–Related Enzymes in Pulmonary Neuroendocrine Carcinoma: Differences in Biological Properties Compared to Epithelial Carcinoma

BackgroundDihydropyrimidine dehydrogenase (DPD), orotate phosphoribosyl transferase (OPRT), and thymidylate synthase (TS) levels correlate with sensitivity and resistance to 5-fluorouracil (5-FU). Few data are available on these enzymes in pulmonary neuroendocrine carcinoma, because 5-FU appears to have minimal effect on such carcinomas. Patients and MethodsThis study investigated 5-FU–related enzymes in large-cell neuroendocrine carcinoma (LCNEC; n = 31) and small-cell lung carcinoma (SCLC; n = 15), comparing expression levels with epithelial carcinomas including adenocarcinoma (ADC; n = 34) and squamous cell carcinoma (SCC; n = 13) obtained from 93 patients with primary lung tumors. Levels of 5-FU–related enzyme mRNA were analyzed by laser capture microdissection, compared with immunohistochemical findings and correlated with clinicopathologic factors. ResultsLCNEC and SCLC showed significantly higher TS and OPRT mRNA levels than ADC. SCLC exhibited significantly higher TS mRNA levels than LCNEC (P = .002). LCNEC displayed significantly lower DPD mRNA levels than ADC (P < .001), with a similar tendency in SCLC. SCC showed significantly lower DPD (P < .01) and higher OPRT (P < .001) mRNA levels than ADC. When we divide the data by pathology into epithelial carcinoma and neuroendocrine carcinoma, malignant potentials and prognoses correlated with mRNA levels in epithelial carcinoma, but not in neuroendocrine carcinoma. Immunohistochemically, neuroendocrine carcinomas were immunonegative for DPD. A significant correlation was found between enzymatic mRNA and protein expression for DPD (R = .500) and a weak correlation was observed for TS (R = .294). ConclusionNeuroendocrine carcinomas show characteristic patterns of expression for 5-FU–related enzymes, including low DPD mRNA and protein level and high TS mRNA level compared with adenocarcinomas. These results partially explain why 5-FU–based chemotherapy shows minimal efficacy against SCLC. Conversely, clinicopathological data and survival analysis indicates that 5-FU–related enzymes themselves might not affect the malignant potential of neuroendocrine carcinoma. Expressional differences in 5-FU–related enzymes among pathologies may provide valuable information for tailor-made chemotherapy.

Possibility of using mRNA expression levels for nucleic acid-metabolizing enzymes within prostate cancer cells as indices for prognostic factors

Thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD), thymidine phosphorylase (TP) and orotate phosphoribosyl transferase (OPRT) are enzymes involved in nucleic acid metabolism. It has been reported (based on observations of various tumor types) that the extent of the mRNA expression of these enzymes within tumor tissues may be used as a factor to define tumor prognosis. It has also been reported that the mRNA expression patterns differ in each type of tumor. However, few reports are available on the distribution of mRNA expression in prostate cancers. This study was conducted on tissue specimens obtained from 172 patients who were diagnosed with prostate cancer and had undergone total prostatectomies. The mRNA expression of TS, DPD, OPRT and TP was quantitatively analyzed using the Danenberg tumor profile (DTP) method. The results were used to examine the correlations between the distributions of the mRNAs and clinicopathological factors, as well as the significance of their expression as a prognostic factor. Patients with poorly differentiated cancers in their tissues showed a significant increase in the mRNA expression of TS and OPRT. The increases in the TP mRNA content were proportional to an increase in the Gleason scores. The prognosis was significantly poorer in those cases with a high expression of TS or OPRT mRNA and a low expression of DPD mRNA. In conclusion, the expression levels of mRNAs for TS, DPD and OPRT among the enzymes related to nucleic acid metabolism are useful as prognostic factors in patients with prostate cancers.

Effects of Lentinan alone and in combination with fluoropyrimidine anticancer agent on growth of human oral squamous cell carcinoma in vitro and in vivo

Chemotherapy has shown little antitumor activity against advanced oral squamous cell carcinoma (OSCC) patients. Therefore, there is an urgent need to develop more effective therapeutic methods for patients with advanced OSCC. Lentinan, beta-(1-->3)-D-glucan, an extract from the edible mushroom, Lentinus edodes, has been reported to show direct antitumor effects and various immunomodulatory effects. S-1 is an oral antineoplastic agent that can induce apoptosis in various types of cancer cells, including OSCC. Hence, combined treatment of cancer cells with Lentinan and S-1 might exert dramatic antitumor effects on OSCC cells. In this study, the response of human OSCC cells to Lentinan alone and in combination with S-1 was examined using nude mouse xenograft models. S-1 (6.9 mg/kg/day, 7 times/week) was administered orally and Lentinan (0.1 mg/kg/day, 2 times/week) was injected into peritumoral tissue for three weeks. Apoptotic cells were detected by a TUNEL method. The gene expression level of thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD) and orotate phosphoribosyl transferase (OPRT) was determined using microdissection and RT-PCR, and their protein levels were determined using ELISA. Combined therapy of Lentinan and S-1 markedly exerted antitumor effects on human OSCC xenografts and significantly induced apoptotic cells in tumors treated with Lentinan plus S-1. Microdissection and RT-PCR revealed that the expression of TS and DPD mRNA was down-regulated and that expression of OPRT mRNA was up-regulated in tumors administered the combined treatment. Moreover, ELISA indicated that the protein levels of TS and DPD were down-regulated, and that OPRT was up-regulated in tumors treated with the combined therapy. During the experimental period, no loss of body weight was observed in mice treated with the combined therapy. These findings demonstrate that the combination of Lentinan and S-1 is effective against OSCC and has the potential of being a new therapeutic tool for future treatment of these tumors.

Adipose Tissue–derived Mesenchymal Stem Cells Expressing Prodrug-converting Enzyme Inhibit Human Prostate Tumor Growth

The ability of human adipose tissue-derived mesenchymal stem cells (AT-MSCs), engineered to express the suicide gene cytosine deaminase::uracil phosphoribosyltransferase (CD::UPRT), to convert the relatively nontoxic 5-fluorocytosine (5-FC) into the highly toxic antitumor 5-fluorouracil (5-FU) together with their ability to track and engraft into tumors and micrometastases makes these cells an attractive tool to activate prodrugs directly within the tumor mass. In this study, we tested the feasibility and efficacy of these therapeutic cells to function as cellular vehicles of prodrug-activating enzymes in prostate cancer (PC) therapy. In in vitro migration experiments we have shown that therapeutic AT-MSCs migrated to all the prostate cell lines tested. In a pilot preclinical study, we observed that coinjections of human bone metastatic PC cells along with the transduced AT-MSCs into nude mice treated with 5-FC induced a complete tumor regression in a dose dependent manner or did not even allow the establishment of the tumor. More importantly, we also demonstrated that the therapeutic cells were effective in significantly inhibiting PC tumor growth after intravenous administration that is a key requisite for any clinical application of gene-directed enzyme prodrug therapies.

Identification of gene signatures involved in the mechanisms of multidrug resistance.

Identification of gene signatures involved in the mechanisms of multidrug resistance.

Combined evaluation of dihydropyrimidine dehydrogenase and thymidine phosphorylate mRNA levels in tumor predicts the histopathological effect of 5-fluorouracil-based chemoradiotherapy

Recent clinical studies have indicated that intra-tumoral gene expression levels of 5-fluorouracil (5-FU) metabolism-related enzymes may predict the clinical response of several cancers to 5-FU-based chemotherapy. However, few studies examining oral squamous cell carcinomas (OSCCs) have been reported. In this study, we determined the expression levels of 5-FU metabolism-related enzymes like thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD), thymidine phosphorylate (TP) and orotate phosphoribosyl transferase (OPRT) using reverse transcription-polymerase chain reaction (RT-PCR) combined with laser capture microdissection (LCM). We also evaluated the correlation between the mRNA expressions of these genes and clinico-pathological factors or the treatment effects of 5-FU-based chemotherapy combined with radiotherapy in 27 patients with OSCC. No significant correlation was observed between the mRNA expression levels of any of the examined genes and the T-stage, N-stage, differentiation grade or mode of tumor invasion. Although TS and OPRT mRNA were not correlated with the histopathological effects and the development of tumor recurrence, DPD and TP mRNA were significantly correlated with the histopathological effects and tumor recurrence. A significant positive correlation was also observed between the expression of TS and DPD mRNA, but no other correlations were observed among the other genes. Our results suggest that the combined evaluation of TP and DPD mRNA expression in tumor cells using LCM and RT-PCR may be a useful predictor of the efficacy of 5-FU-based chemotherapy combined with radiotherapy in patients with OSCC.

Efficacy of laser capture microdissection plus RT-PCR technique in analyzing gene expression levels in human gastric cancer and colon cancer

BackgroundThymidylate synthase, dihydropyrimidine dehydrogenase, thymidine phosphorylase, and orotate phosphoribosyltransferase gene expressions are reported to be valid predictive markers for 5-fluorouracil sensitivity to gastrointestinal cancer. For more reliable predictability, their expressions in cancer cells and stromal cells in the cancerous tissue (cancerous stroma) have been separately investigated using laser capture microdissection.MethodsThymidylate synthase, dihydropyrimidine dehydrogenase, thymidine phosphorylase, and orotate phosphoribosyltransferase mRNA in cancer cells and cancerous stroma from samples of 47 gastric and 43 colon cancers were separately quantified by reverse transcription polymerase chain reaction after laser capture microdissection.ResultsIn both gastric and colon cancers, thymidylate synthase and orotate phosphoribosyltransferase mRNA expressions were higher (p < 0.0001, p <0.0001 respectively in gastric cancer and P = 0.0002, p < 0.0001 respectively in colon cancer) and dihydropyrimidine dehydrogenase mRNA expressions were lower in cancer cells than in cancerous stroma (P = 0.0136 in gastric cancer and p < 0.0001 in colon cancer). In contrast, thymidine phosphorylase mRNA was higher in cancer cells than in cancerous stroma in gastric cancer (p < 0.0001) and lower in cancer cells than in cancerous stroma in colon cancer (P = 0.0055).ConclusionBy using this method, we could estimate gene expressions separately in cancer cells and stromal cells from colon and gastric cancers, in spite of the amount of stromal tissue. Our method is thought to be useful for accurately evaluating intratumoral gene expressions.

Orotate phosphoribosyltransferase expression level in tumors is a potential determinant of the efficacy of 5-fluorouracil

Although the intratumoral expression levels of thymidylate synthase (TS) and dihydropyrimidine dehydrogenase (DPD) are known to affect the antitumor activity of 5-fluorouracil (5-FU), the importance of orotate phosphoribosyltransferase (OPRT) has remained unclear. This study investigated the relationship between intratumoral OPRT expression and the antitumor activity of 5-FU using human NCI60 cell lines with similar levels of TS and DPD messenger RNAs, as well as 31 tumor xenografts. The OPRT mRNA level was positively correlated with the 5-FU efficacy in these cell lines. In vitro, the 50% growth-inhibitory concentrations of 5-FU were closely correlated with the OPRT mRNA levels in cancer cell lines with similar levels of TS mRNAs when combined with a DPD inhibitor. Moreover, downregulation of OPRT with small-interfering RNA decreased the sensitivities of the cultured tumor cells to 5-FU. These results suggest that the OPRT expression level in tumors is an additional determinant of the efficacy of 5-FU.

Relationship between expression of 5-fluorouracil metabolic enzymes and 5-fluorouracil sensitivity in esophageal carcinoma cell lines

5-Fluorouracil (5-FU) is a key drug in the treatment of esophageal squamous cell carcinoma (ESCC). Gene expression of 5-FU metabolic enzymes such as thymidylate synthase (TS), thymidine phosphorylase (TP), dihydropyrimidine dehydrogenase (DPD) and orotate phosphoribosyl transferase (OPRT), has recently been investigated in order to predict the 5-FU sensitivity of several cancers. We examined the relationship between such gene expression and 5-FU sensitivity in 25 ESCC cell lines. TS, DPD, TP and OPRT mRNA levels were assessed by real-time polymerase chain reaction. The 50% inhibitory concentrations (IC50) of 5-FU in 25 ESCC cell lines were determined by cell proliferation assay. IC50 values for 5-FU ranged from 1.00 to 39.81 micromol/L. There were significant positive correlations between IC50 and TS mRNA expression (R(2) = 0.5781, P < 0.0001) and DPD mRNA expression (R(2) = 0.3573, P = 0.0016). There were no correlations between IC50 and TP or OPRT mRNA expression. TS and DPD mRNA expression levels may be useful indicators in predicting the anti-tumor activity of 5-FU in ESCC.

Role of thymidine phosphorylase and orotate phosphoribosyltransferase mRNA expression and its ratio to dihydropyrimidine dehydrogenase in the prognosis and clinicopathological features of patients with pancreatic cancer

Thymidine phosphorylase (TP), orotate phosphoribosyltransferase (OPRT), and dihydropyrimidine dehydrogenase (DPD) are important enzymes related to the metabolism of 5-fluorouracil and its derivatives. In this study, we analyzed the expression of these enzymes and evaluated the association between the expression of these enzymes and clinicopathological features and prognosis in patients with pancreatic cancer. TP, OPRT, and DPD mRNA expressions were detected using a real-time reverse transcriptional-polymerase chain reaction method or by immunohistochemistry, using surgical specimens obtained from 25 patients with pancreatic cancer. TP mRNA expression was lower in cases with an alpha infiltration growth pattern than in cases with other infiltration growth patterns (P < 0.05). OPRT mRNA expression was higher in poorly differentiated-type cases than in differentiated type cases (P < 0.05). TP-, OPRT-, and DPD-positive stainings were found in 15 of 24 cases (63%), 10 of 19 cases (53%), and 14 of 21 cases (67%), respectively. There were significant correlations or trends between the mRNA and protein expressions of TP, OPRT, and DPD. Patients with a low TP/DPD ratio survived significantly longer than those with a high ratio (P < 0.05). Multivariate analysis demonstrated a significantly poorer outcome in patients with a high TP/DPD ratio compared with in patients with a low ratio (P < 0.05). The TP/DPD ratio might be useful as a prognostic factor in patients with pancreatic cancer.

Gene expression of 5-fluorouracil metabolic enzymes in primary gastric cancer: Correlation with drug sensitivity against 5-fluorouracil

Thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD), thymidine phosphorylase (TP), and orotate phosphoribosyltransferase (OPRT) have been reported to be predictive parameters for the efficacy of fluoropyrimidine-based chemotherapy. mRNA expression of TS, DPD, TP, and OPRT were quantified by reverse-transcriptase polymerase chain reaction after harvesting cancer cells from 93 paraffin-embedded specimens of gastric cancer through laser capture microdissection. In vitro chemosensitivity testing by histoculture drug response assay was performed with surgically resected primary lesions of the same 93 patients. No significant correlation was observed between the mRNA expression and location of the tumor, histopathologic type, clinical stage, and other clinicopathologic variables, with the exception that OPRT mRNA had a weak correlation with drug sensitivity against 5FU ( R = 0.219, p = 0.0343). OPRT was considered to have a major impact on drug sensitivity, although not sufficiently so to enable prediction of 5FU sensitivity solely based on the mRNA expression of this enzyme.

Efficacy of S-1 for Patients with Peritoneal Metastasis of Gastric Cancer

Background: This study was designed to examine the efficacy and compliance of S-1 for the patients with peritoneal metastasis of gastric cancer. Methods: Sixteen consecutive patients with peritoneal metastasis of gastric cancer were treated with S-1. Their survival was compared with that of the historical control group (25 patients). Thymidylate synthase, dihydropyrimidine dehydrogenase, thymidine phosphorylase and orotate phosphoribosyl transferase mRNA expression in the tumor were evaluated. Results: The median survival time of S-1-treated patients was 550 days, which was significantly longer than that of the historical control group (215 days). We elucidated some factors to prolong the survival of the patients treated with S-1 for peritoneal metastasis: peritoneal metastasis without other distant metastases, the combination of S-1 treatment and gastrectomy, and low expression of thymidine phosphorylase mRNA in primary tumors. Conclusions: S-1 showed a surprisingly long-term survival with minimum toxicity in patients with peritoneal metastasis of gastric cancer.

Orotate phosphoribosyl transferase mRNA expression in oral squamous cell carcinoma and its relationship with the dihydropyrimidine dehydrogenase expression and the clinical effect of 5-fluorouracil

In this study, we investigated whether orotate phosphoribosyl transferase (OPRT) correlates with the clinicopathological features and effect of 5-fluorouracil (5-FU) in human oral carcinoma. We examined the expression of OPRT mRNA by in situ hybridization in surgical specimens of oral squamous cell carcinoma. The expression of OPRT mRNA in oral carcinoma was observed in all specimens and such expression was higher than that seen in normal control tissue specimens. There was no correlation between the expression of OPRT mRNA and clinical factors, but the expression of OPRT mRNA was significantly associated with histological differentiation. The expression of OPRT mRNA showed correlation with effect of 5-FU for oral carcinoma in either in vivo or in vitro. These results suggest that the OPRT expressions may therefore be a prognostic factor of 5-FU efficacy in patients with oral squamous cell carcinoma.