Stimulation of 5-fluorouracil metabolic activation by interferon-alpha in human colon carcinoma cells

Fluoropyrimidine Modulation of the Anti-Tumor Immune Response-Prospects for Improved Colorectal Cancer Treatment

Chemotherapy modulates the anti-tumor immune response and outcomes depend on the balance of favorable and unfavorable effects of drugs on anti-tumor immunity. 5-Florouracil (5-FU) is widely used in adjuvant chemotherapy regimens to treat colorectal cancer (CRC) and provides a survival benefit. However, survival remains poor for CRC patients with advanced and metastatic disease and immune checkpoint blockade therapy benefits only a sub-set of CRC patients. Here we discuss the effects of 5-FU-based chemotherapy regimens to the anti-tumor immune response. We consider how different aspects of 5-FU's multi-factorial mechanism differentially affect malignant and immune cell populations. We summarize recent studies with polymeric fluoropyrimidines (e.g., F10, CF10) that enhance DNA-directed effects and discuss how such approaches may be used to enhance the anti-tumor immune response and improve outcomes.

Efficacy of hepatic arterial infusion chemotherapy using 5-fluorouracil and systemic pegylated interferon α-2b for advanced intrahepatic cholangiocarcinoma

BACKGROUND

Cholangiocarcinoma is categorized into intrahepatic cholangiocarcinoma (ICC) and extrahepatic cholangiocarcinoma (ECC). The prognosis of ICC is far worse than that of ECC. In this pilot trial, the efficacy of hepatic arterial infusion chemotherapy (HAIC) using 5-fluorouracil (5-FU) combined with subcutaneous administration of pegylated interferon (PEG-IFN) α-2b in patients with advanced ICC was evaluated.

METHODS

The subjects were 20 advanced ICC patients treated using subcutaneous PEG-IFNα-2b (50-100 μg on day 1 of every week, for 4 weeks) and intra-arterial infusion of 5-FU (250 mg/day for 5 h on days 1-5 of every week, for 4 weeks). One treatment cycle lasted 4 weeks. Therapy was discontinued in patients with progressive disease (PD). For responses other than PD, treatment was repeated for ≥1 cycle.

RESULTS

The objective early response rate was 60.0 %. Cumulative survival rates were 71.6 % at 6 months, 53.7 % at 12 months, 28.6 % at 18 months, and 14.3 % at 24 months. Median survival time was 14.6 months. All adverse reactions were controllable by temporary suspension of treatment. Serious complications and treatment-related deaths were not observed.

CONCLUSIONS

The combination therapy of PEG-IFNα-2b and 5-FU for advanced ICC seems not to be worse than the results of the previous studies. Furthermore, most adverse effects are transient and well tolerated. Based on the present findings, this combination therapy may be useful for patients with advanced ICC as one of the therapeutic option.

Thymidine phosphorylase is both a therapeutic and a suicide gene in a murine model of mitochondrial neurogastrointestinal encephalomyopathy

Suicide gene therapy (SGT) is a promising strategy for treating cancer. In this work, we show that thymidine phosphorylase (TP) deficiency, the underlying genetic defect in mitochondrial neurogastrointestinal encephalomyopathy (MNGIE), presents an opportunity to apply SGT using capecitabine, a commonly used prodrug that is converted into 5-fluorouracil by TP. Using an immortalised B-lymphoblastoid cell line from a patient with MNGIE, the tumourigenic EL-4 cell line, lentiviral vectors encoding TP and a double knockout (Tymp(-/-)Upp1(-/-)) murine model, we found that EL-4 cell-derived TP(+) tumours were exquisitely sensitive to capecitabine and generated a significant local bystander effect. In addition, we detected a spontaneous cytolytic immune response in a significant fraction of the animals surviving more than 20 days after termination of the therapy. These data indicate that, in individuals lacking TP expression, TP is a highly specific suicide gene, which can be used to treat tumours that could hypothetically arise in MNGIE patients undergoing gene therapy, as these tumours will likely originate from the gene-modified cells and will be selectively targeted by capecitabine. These observations have important implications for gene therapy for MNGIE.

Therapeutic efficacy of combination therapy with intra-arterial 5-fluorouracil and systemic pegylated interferon α-2b for advanced hepatocellular carcinoma with portal venous invasion

BACKGROUND

The prognosis of advanced hepatocellular carcinoma (HCC) remains poor, particularly among patients with portal vein tumor thrombosis (PVTT). This study evaluated the efficacy of combined 5-fluorouracil and pegylated interferon (PEG-IFN) α-2b in patients with advanced HCC.

METHODS

Subjects comprised 59 HCC patients with PVTT treated using subcutaneous administration of PEG-IFNα-2b (50-100 μg on day 1 of each week for 4 weeks) and intra-arterial infusion of 5-fluorouracil (250 mg/d for 5 hours on days 1-5 of each week for 4 weeks). One treatment cycle lasted 4 weeks. The current therapy was discontinued in patients with progressive disease (PD). For responses other than PD, treatment was repeated for ≥1 cycle. The primary efficacy endpoint was the objective early response rate. Secondary efficacy endpoints were progression-free survival (PFS) and overall survival.

RESULTS

Objective early response rate was 73.0%. Cumulative PFS rates were 67.4% at 6 months, 30.2% at 12 months, 25.9% at 18 months, and 20.7% at 24 months. Median PFS was 9.7 months. Cumulative survival rates were 82.4% at 6 months, 73.6% at 12 months, 52.8% at 24 months, and 44.0% at 36 months. Median survival time was 29.9 months. All adverse reactions were controllable by temporary suspension of treatment. Serious complications and treatment-related deaths were not observed.

CONCLUSIONS

Although a prospective randomized controlled trial using a larger population of patients with advanced HCC is needed to evaluate combination therapy with 5-fluorouracil and PEG-IFNα-2b, this new combination therapy may be useful for patients with advanced HCC.

Differential expression of uridine phosphorylase in tumors contributes to an improved fluoropyrimidine therapeutic activity

Abrogation of uridine phosphorylase (UPase) leads to abnormalities in pyrimidine metabolism and host protection against 5-fluorouracil (5-FU) toxicity. We elucidated the effects on the metabolism and antitumor efficacy of 5-FU and capecitabine (N(4)-pentyloxycarbonyl-5'-deoxy-5-fluorocytidine) in our UPase knockout (UPase(-/-)) model. Treatment with 5-FU (85 mg/kg) or capecitabine (1,000 mg/kg) five days a week for four weeks caused severe toxicity and structural damage to the intestines of wild-type (WT) mice, but not in UPase(-/-) animals. Capecitabine treatment resulted in a 70% decrease in blood cell counts of WT animals, with only a marginal effect in UPase(-/-) mice. UPase expressing colon 38 tumors implanted in UPase(-/-) mice revealed an improved therapeutic efficacy when treated with 5-FU and capecitabine because of the higher maximum tolerated dose for fluoropyrimidines achievable in UPase(-/-) mice. (19)F-MRS evaluation of capecitabine metabolism in tumors revealed similar activation of the prodrug in UPase(-/-) mice compared with WT. In WT mice, approximately 60% of capecitabine was transformed over three hours into its active metabolites, whereas 80% was transformed in tumors implanted in UPase(-/-) mice. In UPase(-/-) mice, prolonged retention of 5'dFUR allowed a proportional increase in tumor tissue. The similar presence of fluorinated catabolic species confirms that dihydropyrimidine dehydrogenase activity was not altered in UPase(-/-) mice. Overall, these results indicate the importance of UPase in the activation of fluoropyrimidines, the effect of uridine in protecting normal tissues, and the role for tumor-specific modulation of the phosphorolytic activity in 5-FU or capecitabine-based chemotherapy.

Combination of interferon-α and 5-fluorouracil induces apoptosis through mitochondrial pathway in hepatocellular carcinoma in vitro

Many clinical reports have proven that the combination therapy of interferon-alpha plus 5-fluorouracil is remarkably effective for advanced hepatocellular carcinoma (HCC). However, the mechanism of this therapy is not well understood. Here, we demonstrated that the combination therapy synergistically inhibited the growth of Fas-negative HCC cells, arrested cell-cycle progression and induced apoptosis. Moreover, the combination therapy significantly increased the protein expression of caspase-8, activated Bid and cytochrome c. Meanwhile, the expression of anti-apoptotic gene Bcl-xL was reduced and intracellular calcium elevated obviously during the early stage of treatment. Therefore, mitochondrial pathway was involved in the apoptosis of Fas-negative HCC cells induced by IFN-α/5-FU and Ca(2+) partially promoted the beneficial effect against HCC.

Type 1 interferon receptor in peripheral blood mononuclear cells may predict response to intra-arterial 5-fluorouracil + interferon therapy for advanced hepatocellular carcinoma

BACKGROUND

Type 1 interferon alpha receptor 2 (IFNAR2) in the liver has been reported to be a predictive factor for the response to intra-arterial 5-fluorouracil (5-FU) + systemic interferon (IFN)-alpha combination therapy in patients with advanced hepatocellular carcinoma. We tested whether IFNAR2 expression in peripheral blood mononuclear cells could predict the response to 5-FU + IFN.

METHODS

Predictive factors for survival and response to therapy were determined in 30 patients with advanced hepatocellular carcinoma who underwent treatment with 5-FU + IFN. IFNAR2 expression in peripheral blood mononuclear cells was measured in 11 of the 30 patients.

RESULTS

With a mean number of 4.2 courses of combination therapy, one patient (3%) showed a complete response, eight (27%) showed partial responses, 13 (43%) had stable disease, and eight (27%) showed progressive disease. The median survival time of responders (complete response/partial response) was 12.7 months and that of nonresponders (stable disease/progressive disease) was 7.5 months. The one-year and two-year cumulative survival rates of responders and nonresponders were 87/69% and 40/11%, respectively (P = 0.019). Multivariate analysis identified response to therapy (P = 0.037) as the sole independent determinant of survival. The expression level of IFNAR2 in peripheral blood mononuclear cells was significantly (P = 0.012) higher in responders (6.5 ± 2.4) than in nonresponders (2.4 ± 0.6), even though no clinical factors were identified as being associated with the response to the combination therapy.

CONCLUSION

IFNAR2 expression in peripheral blood mononuclear cells may predict the response to 5-FU + IFN therapy in patients with advanced hepatocellular carcinoma, although these data are preliminary.

Combination therapy of intra-arterial 5-fluorouracil and systemic pegylated interferon α-2b for advanced hepatocellular carcinoma

BACKGROUND

This study evaluated the efficacy of combined 5-fluorouracil (5-FU) and pegylated interferon (PEG-IFN) α-2b in patients with advanced hepatocellular carcinoma (HCC).

METHODS

Fifty patients with portal vein tumor thrombosis were enrolled. Of these, 21 patients were treated using subcutaneous administration of PEG-IFNα-2b and intra-arterial infusion of 5-FU (5-FU/PEG-IFN group), 12 patients were treated using intramuscular administration of IFNα-2b and intra-arterial infusion of 5-FU (5-FU/IFN group), and 17 patients received intra-arterial infusion chemotherapy with lipiodol-cisplatin (CDDP) suspension (CDDP group).

RESULTS

The objective early response rate was significantly higher in the 5-FU/PEG-IFN group than in the 5-FU/IFN or CDDP groups (71.4 vs. 8.3% and 17.6%, respectively; P < 0.0001). Cumulative survival rates at 6 and 12 months were 83.8 and 77.8% in the 5-FU/PEG-IFN group, 60.8 and 16.2% in the 5-FU/IFN group, and 58.4 and 12.5% in the CDDP group, respectively. The cumulative survival rate was significantly higher in the 5-FU/PEG-IFN group than in the other 2 groups (P = 0.0272). Serious complications and treatment-related deaths were not observed in any of the 3 groups.

CONCLUSION

Although a prospective randomized controlled trial using a larger population of patients with advanced HCC is needed to evaluate combination therapy with 5-FU and PEG-IFNα-2b, this new combination therapy may be useful for patients with advanced HCC.

Hepatocellular carcinoma, with portal thrombus after viral eradication, disappeared by 5-fluorouracil and interferon

Hepatocarcinogenesis after a sustained virological response (SVR) in type C chronic hepatitis and cirrhosis is an important issue in endemic areas; hepatocellular carcinoma (HCC) with portal vein tumor thrombus (PVTT) therapy is especially very hard. We herein report a first case in which combination therapy with interferon-α and continuous intra-arterial infusion of 5-fluorouracil (designated as FAIT) provided a complete response in HCC with PVTT after SVR. Therefore, we think that FAIT is a good option to treat HCC with or without PVTT, even after SVR.

Combination of interferon-alpha and 5-fluorouracil inhibits endothelial cell growth directly and by regulation of angiogenic factors released by tumor cells

Background

The combination therapy of interferon (IFN)-alpha and 5-fluorouracil (5-FU) improved the prognosis of the patients with hepatocellular carcinoma (HCC). To determine the molecular mechanisms of the anti-tumor and anti-angiogenic effects, we examined the direct anti-proliferative effects on human umbilical vein endothelial cells (HUVEC) and indirect effects by regulating secretion of angiogenic factors from HCC cells.

Methods

The direct effects on HUVEC were examined by TUNEL, Annexin-V assays and cell cycles analysis. For analysis of the indirect effects, the apoptosis induced by the conditioned medium from HCC cell treated by IFN-alpha/5-FU and expression of angiogenic factors was examined.

Results

IFN-alpha and 5-FU alone had anti-proliferative properties on HUVEC and their combination significantly inhibited the growth (compared with control, 5-FU or IFN alone). TUNEL and Annexin-V assays showed no apoptosis. Cell cycle analysis revealed that IFN-alpha and 5-FU delayed cell cycle progression in HUVEC with S-phase accumulation. The conditioned medium from HuH-7 cells after treatment with IFN/5-FU significantly inhibited HUVEC growth and induced apoptosis, and contained high levels of angiopoietin (Ang)-1 and low levels of vascular endothelial growth factor (VEGF) and Ang-2. Knockdown of Ang-1 in HuH-7 cells abrogated the anti-proliferative effects on HUVEC while knockdown of Ang-2 partially rescue the cells.

Conclusion

These results suggested that IFN-alpha and 5-FU had direct growth inhibitory effects on endothelial cells, as well as anti-angiogenic effects through regulation of angiogenic factors released from HCC cells. Modulation of VEGF and Angs secretion by IFN-alpha and 5-FU may contribute to their anti-angiogenic and anti-tumor effects on HCC.

Evaluation of newly developed combination therapy of intra-arterial 5-fluorouracil and systemic pegylated interferon alpha-2b for advanced hepatocellular carcinoma with portal venous invasion: preliminary results

AIM

Prognosis is extremely poor for advanced hepatocellular carcinoma (HCC) in patients with portal invasion. The present study evaluated the efficacy of combined intra-arterial 5-fluorouracil (5-FU) and systemic pegylated interferon (PEG-IFN)alpha-2b in patients with advanced HCC.

METHODS

The subjects comprised nine HCC patients with portal vein thrombosis treated using subcutaneous administration of PEG-IFNalpha-2b (50-100 microg on day 1 of every week, for 4 weeks) and intra-arterial infusion of 5-FU (250 mg/day for 5 h on days 1-5 of every week, for 4 weeks). For four patients with hepatitis C virus (HCV) infection, oral administration of ribavirin (400-800 mg/day) was added. At the end of every cycle, response to therapy was assessed using Response Evaluation Criteria in Solid Tumors (RECIST) guidelines.

RESULTS

Partial response (PR) was observed in seven of nine patients, with stable or progressive disease in the remaining two patients. Tumors were resectable in three patients displaying PR after treatment. Tumor markers decreased significantly after therapy. Serum HCV-RNA titers were markedly decreased and became undetectable in all patients with HCV infection. National Cancer Institute-Common Toxicity Criteria: version 3.0 (NCI-CTC) grade 3 thrombocytopenia was seen in one case at the end of treatment, but was resolved with cessation of treatment. Other adverse effects were manageable.

CONCLUSION

Combination therapy with intra-arterial 5-FU and systemic PEG-IFNalpha-2b may be useful as a palliative treatment for patients with advanced HCC. A prospective controlled trial using a larger population of patients with advanced HCC is needed to evaluate this new combination therapy.

Interferon-alpha and 5-fluorouracil combination therapy after palliative hepatic resection in patients with advanced hepatocellular carcinoma, portal venous tumor thrombus in the major trunk, and multiple nodules

BACKGROUND

The authors reported previously the beneficial effects of interferon (IFN)-alpha/5-fluorouracil (5-FU) combination therapy for patients with advanced hepatocellular carcinoma (HCC) who have tumor thrombi in the major portal branches. In this report, the authors describe the results from IFN/5-FU chemotherapy for patients who underwent palliative hepatic resection for advanced HCC with tumor thrombus in the main trunk of the portal vein and multiple nodules in the whole liver. In addition, they evaluated the correlation between the response to such therapy and expression of IFN-alpha type 2 receptor (IFNAR2).

METHODS

From October 1999 to December 2004, 30 patients with advanced HCC, tumor thrombi in the main trunk of the portal vein, and multiple nodules in the whole liver (Vp4 and grade 3 intrahepatic metastases) were recruited for this study. They underwent palliative hepatic resection followed by at least 2 courses of IFN/5-FU. IFNAR2 expression levels were determined by immunohistochemistry.

RESULTS

No major treatment-related complications were noted. An objective response was noted in 10 patients (33.3%) and included a complete response in 6 patients (20%), a partial response in 4 patients (13.3%), no response in 1 patient (3.3%), and progressive disease in 19 patients (63.4%). IFNAR2 expression was detected in 20 of 30 patients (66.7%). There was a significant difference in overall survival between patients with positive and negative IFNAR2 expression cases (P<.0025), and a significant correlation was observed between IFNAR2 expression and response to IFN/5-FU combination therapy (P=.0199).

CONCLUSIONS

Adjunct IFN/5-FU therapy is a promising modality for patients with advanced HCC, tumor thrombi in the major trunk, and multiple nodules after palliative hepatic resection. The results from this study indicated that the response to such therapy seemed to be correlated with IFNAR2 expression.

Similar effects of recombinant interferon-alpha-2b and natural interferon-alpha when combined with intra-arterial 5-fluorouracil for the treatment of advanced hepatocellular carcinoma

AIM

Intra-arterial 5-fluorouracil (5-FU) plus interferon (IFN) combination therapy is effective against advanced hepatocellular carcinoma (HCC) with portal vein tumour thrombosis. In this study, we compared the efficiency and safety of recombinant IFN-alpha-2b with natural IFN-alpha as components of the combination therapy.

METHODS

Consecutive HCC patients (n=31) with portal vein tumour thrombosis were enrolled in this prospective study. They received combination therapy of 5-FU and either recombinant IFN-alpha-2b (R group, n=15) or natural IFN-alpha (N group, n=16). We compared the two groups for the early response rate, adverse reactions, time to progression (TTP) and survival rates. In addition, we assessed the cost-effectiveness of each protocol.

RESULTS

The early response rate (R: 26.7%, N: 31.2%), median TTP (R: 5.8 months, N: 5.6 months) and median survival time (R: 7.5 months, N: 6.5 months) were not significantly different between the R and N groups. There were no differences in adverse reactions between the two groups. The estimated cost-effectiveness ratio of recombinant IFN-alpha-2b was better than natural IFN-alpha.

CONCLUSIONS

In our protocol of combination therapy, there were no significant differences between recombinant IFN-alpha-2b and natural IFN-alpha with regard to early response to therapy, adverse effects, TTP and survival rates. 5-FU could be combined with either recombinant IFN-alpha-2b or natural IFN-alpha, although the cost-effectiveness of the former warrants its use clinically.

Combination therapy with PEG-IFN-alpha and 5-FU inhibits HepG2 tumour cell growth in nude mice by apoptosis of p53

When the tumour suppressor p53 is activated by DNA damage, it stimulates the transcription of its target genes, which then induce cell cycle arrest or apoptosis. Here, we examined the role p53 plays in the antitumour effect of combination treatment with pegylated interferon (PEG-IFN)-alpha and 5-fluorouracil (5-FU), which has been shown to effectively treat advanced hepatocellular carcinoma (HCC). Nude mice were injected subcutaneously with cultured HepG2 cells, in which p53 is functional. They were treated a week later with PEG-IFN and/or 5-FU for 7 weeks, after which we measured and examined their tumours. Combination groups showed significantly lower tumour volumes and higher tumour cell apoptosis than the other groups. Combination treatment and PEG-IFN monotherapy also significantly elevated the p53 protein and mRNA levels in the tumour but only combination treatment increased the degree of p53 phosphorylation at serine46 and induced p53-regulated apoptosis-inducing protein 1 (p53AIP1) expression. The antitumour effects of combination treatment is due in part to the elevation by PEG-IFN of p53 protein and mRNA expression and in part to the DNA damage that is generated by 5-FU, which induces p53 serine46 phosphorylation, which in turn upregulates p53AIP1 expression.

Alteration of dihydropyrimidine dehydrogenase expression by IFN-α affects the antiproliferative effects of 5-fluorouracil in human hepatocellular carcinoma cells

Dihydropyrimidine dehydrogenase (DPD) is the rate-limiting enzyme in the catabolism of 5-fluorouracil (5-FU) and its activity is closely associated with cellular sensitivity to 5-FU. This study examines the role of DPD in the antiproliferative effects of 5-FU combined with IFN-alpha on hepatocellular carcinoma (HCC) cells in culture and asks whether IFN-alpha could affect DPD expression. The combined action of IFN-alpha and 5-FU on three HCC lines was quantified by a combination index method. Coadministration of IFN-alpha and 5-FU showed synergistic effects against HAK-1A and KYN-2 but antagonistic effects against KYN-3. The cellular expression levels of DPD mRNA and protein were markedly up-regulated in KYN-3 cells by IFN-alpha but were down-regulated in HAK-1A and KYN-2. The expression of thymidylate synthase mRNA and protein was down-regulated by IFN-alpha in all three cell lines. Coadministration of a selective DPD inhibitor, 5-chloro-2,4-dihydroxypyridine (CDHP), enhanced the antiproliferative effect of 5-FU and IFN-alpha on KYN-3 approximately 4-fold. However, the synergistic effects of 5-FU and IFN-alpha on HAK-1A and KYN-2 were not affected by CDHP. The antiproliferative effect of 5-FU could thus be modulated by IFN-alpha, possibly through DPD expression, in HCC cells. Inhibition of DPD activity by CDHP may enhance the efficacy of IFN-alpha and 5-FU combination therapy in patients with HCC showing resistance to this therapy.

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

OBJECTIVES

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

METHODS

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

RESULT

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

CONCLUSION

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

Successful treatment of multiple hepatocellular carcinoma with tumor thrombi in the major portal branches by intraarterial 5-fluorouracil perfusion chemotherapy combined with subcutaneous interferon-alpha and hepatectomy

We experienced a patient who received successful treatment for multiple hepatocellular carcinoma (HCC) nodules, with tumor thrombi in the major portal branches, with intraarterial 5-fluorouracil perfusion chemotherapy combined with subcutaneous interferon-alpha administration. The patient was a 50-year-old man with hepatitis C virus and HCC. The tumors consisted of a 5-cm main nodule in the right lobe (segment 8) and multiple intrahepatic metastases. The tumor also involved portal vein thrombosis throughout the right portal branch. After two cycles of interferon-alpha/5-fluorouracil combination chemotherapy, tumor markers demonstrated a decreasing tendency. Nine months after the initiation of this therapy, the tumors were limited to the right lobe and were surgically removed by S8 subsegmentectomy, S5 partial hepatectomy, and portal thrombectomy. The serum levels of both alpha-fetoprotein and protein induced by vitamin K absence II fell to normal levels after hepatic resection. Fifty-eight months after the first treatment, he is alive with several recurrent nodules in the liver. In conclusion, the interferon-alpha/5-fluorouracil combination therapy is a useful treatment for HCC in patients who have multiple intrahepatic metastases and portal vein thrombosis. In addition to this therapy, combined modality therapy including, for example, surgical resection, can sometimes have a dramatic therapeutic effect, shown by tumor markers reverting to normal levels.

Combination therapy of human pancreatic cancer implanted in nude mice by oral fluoropyrimidine anticancer agent (S-1) with interferon-alpha

PURPOSE

We evaluated the antitumor and antiangiogenic activities of human natural interferon-alpha (IFN-alpha) alone or in combination with S-1 against human pancreatic cancer cells.

METHODS

Three days after the subcutaneous (s.c.) implantation of tumor cells, mice (n = 12) were received s.c. injection with IFN-alpha alone (10,000 U six times a week), oral administration with S-1 alone (8 mg/kg six times a week), or both with IFN-alpha and S-1 (8, 10, 12 mg/kg six times a week).

RESULTS

Administration of IFN-alpha in combination with S-1 significantly decreased progressive growth and angiogenesis of human pancreatic cancer cells. The combination therapy produced more significant inhibition in expression of the representative proangiogenic molecules, vascular endothelial growth factor and basic fibroblast growth factor than individual treatment either IFN-alpha or S-1 alone did. These treatments also decreased the staining of proliferating cell nuclear antigen, induced apoptosis and decreased microvessel density. In order to better understand the precise molecular mechanisms by which IFN-alpha and S-1 exert its effects, we have utilized cDNA microarray including 124 known genes to determine the gene expression profile altered by IFN-alpha and S-1 treatment. We found a total of seven genes which showed a twofold change after IFN-alpha and S-1 treatment in addition to VEGF, bFGF, CD31, MMP-2, MMP-7 and MMP-9. Among these genes, we found down-regulation of six genes and up-regulation of one gene, which are related to angiogenesis, tumor cell invasion and metastasis.

CONCLUSIONS

These data suggest that administration of IFN-alpha in combination with S-1 may provide a novel and effective approach to the treatment of human pancreatic cancer.

Antiproliferative effects of 5-fluorouracil and interferon-alpha in combination on a hepatocellular carcinoma cell line in vitro and in vivo

BACKGROUND AND AIM

We investigated the antiproliferative effects of interferon-alpha (IFN-alpha) and 5-fluorouracil (5-FU) in combination on a hepatocellular carcinoma (HCC) cell line.

METHOD

In the in vitro study, IFN-alpha and/or 5-FU was added to the culture of the poorly differentiated-type HCC cell line, HAK-1B, and their antiproliferative effects and additional or synergic effects in combination treatment were examined. In the in vivo study, HAK-1B cells were transplanted into nude mice and the changes in tumor volume and weight, apoptosis, BrdU and cyclin A positive cells, and artery-like blood vessels were investigated. Expressions of angiogenesis factors and IFN-alpha receptor (IFNAR-2) were examined in the developed tumors.

RESULTS

In vitro growth of HAK-1B cells was suppressed dose-dependently to 5-FU, but the addition of IFN-alpha did not induce additional or synergic effects. In vivo growth in terms of tumor diameter and weight was suppressed at most in the IFN-alpha + 5-FU (combination) group, that is, the tumor volume became 29.3% and the tumor weight became 54.7% of the control. In the combination group, numbers of BrdU-positive S-phase cells and cyclin A positive cells increased together with the increase in apoptotic cells, but there was no significant relation between the tumor shrinkage effects and angiogenesis factors or artery-like blood vessels. In the combination group, INFAR-2 decreased significantly in comparison to the other groups.

CONCLUSION

The synergic growth-suppression effects in the current in vivo study using the combination treatment are attributable to the enhanced induction of S-phase arrest and of apoptosis.

Treatment of hepatocellular carcinoma with major portal vein thrombosis by combined therapy with subcutaneous interferon-alpha and intra-arterial 5-fluorouracil; role of type 1 interferon receptor expression

We previously reported the beneficial effects of combination therapy of interferon (IFN)-α/5-fluorouracil (FU) for advanced hepatocellular carcinoma (HCC) with tumour thrombi in the major portal branches. This report describes the results of longer follow-up and includes more than double the number of patients relative to the original report, and evaluates the role of IFN-α/type 2 interferon receptor (IFNAR2) expression on the response to the combination therapy. The study subjects were 55 patients with advanced HCC and tumour thrombi in the major branches of the portal vein (Vp3 or 4). They were treated with at least two courses of IFN-α/5-FU without major complication. In the 55 patients, 24 (43.6%) showed objective response (eight (14.5%) showed complete response, 16 (29.1%) partial response), four (7.3%) showed no response, and 27 (49.1%) showed progressive disease. Immunohistochemically, IFNAR2 expression was detected in nine out of 13 (69.2%) patients. There was significant difference in the time-to-progression survival (P=0.0002) and the overall survival (P<0.0001) between IFNAR2-positive and -negative cases. There was a significant correlation between IFNAR2 expression and response to IFN-α/5-FU combination therapy in univariate analysis (P=0.0070). IFN-α/5-FU combination therapy is a promising modality for advanced HCC with tumour thrombi in the major portal branches and could significantly depend on IFNAR2 expression.

The treatment of advanced colorectal cancer with interferon-alpha: a review

Colorectal cancer (CRC) is one of the most common malignancies in the western world. The majority of patients who develop this tumour will ultimately die from metastatic disease. The fluorinated pyrimidine 5 fluorouracil (5-FU) is at present the most active drug available for first-line therapy of this disease. Randomised studies have consistently demonstrated a survival advantage from early treatment with 5-FU in advanced CRC, which can be achieved without deterioration in quality of life. Despite over 30 years of use, the optimal 5-FU schedule remains controversial with a wide range of response rates reported in the literature. Single agent activity is in the order of 10-11%. In an attempt to improve response rates, modulation of 5-FU with a variety of agents has been intensively investigated. This article examines the role of interferon-alpha in the treatment of advanced CRC.

Partial contribution of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)/TRAIL receptor pathway to antitumor effects of interferon-alpha/5-fluorouracil against Hepatocellular Carcinoma

PURPOSE

Our purpose was to explore the contribution of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)/TRAIL receptor pathway to antitumor effects of IFNalpha and 5-fluorouracil (5-FU) combination therapy for hepatocellular carcinoma (HCC).

EXPERIMENTAL DESIGN

Susceptibility of HCC cell lines to TRAIL and/or 5-FU was examined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The effects of 5-FU, IFNalpha, or both on the expression of TRAIL receptors (R1, R2, R3, and R4) on HCC cells or TRAIL in peripheral blood mononuclear cells (PBMC) were examined by flow cytometry. IFNalpha-induced cytotoxic effects of PBMC on HCC cell lines were examined by (51)Cr release assay. TRAIL expression in peripheral blood mononuclear cells and liver tissue from patients was examined by real-time reverse transcription-PCR or immunohistochemistry.

RESULTS

HLE and HepG2 were sensitive to TRAIL, but HuH7, PLC/PRF/5, and HLF were resistant. 5-FU had synergistic effect on TRAIL in HLF and additive effect in four other HCC cell lines. TRAIL receptors on HCC cells were up-regulated by 5-FU, and IFNalpha induced TRAIL on CD4(+) T cells, CD14(+) monocytes, and CD56(+) NK cells. Treatment of effector cells by IFNalpha and target HCC cells by 5-FU enhanced the cytotoxicity of CD14(+) monocytes and CD56(+) NK cells against HCC cells via a TRAIL-mediated pathway. TRAIL mRNA overexpression was noted in PBMC of HCC patients who clinically responded to IFNalpha/5-FU combination therapy, and TRAIL(+) mononuclear cells were found in cancer tissue of a responder.

CONCLUSION

Our results suggest that modulation of TRAIL/TRAIL receptor-mediated cytotoxic pathway might partially contribute to the anti-HCC effect of IFNalpha and 5-FU combination therapy.

Upregulation of platelet derived endothelial cell growth factor/thymidine phosphorylase by interferon alpha

Thymidine phosphorylase (TP) catalyzes the phosphorolytic cleavage of thymidine to thymine and deoxyribose-1-phosphate. TP, which is overexpressed in a wide variety of solid tumors, is involved in the activation and inactivation of fluoropyrimidines. TP is known to be regulated by several cytokines and interferons. In our HT29 cell line the TP mRNA and activity expression increased 2-3 fold after treatment with interferon alpha.

Combination of IFN- and 5-Fluorouracil Induces Apoptosis through IFN-α/β Receptor in Human Hepatocellular Carcinoma Cells

Purpose: Several studies showed the effectiveness of combination therapy with IFN-α and 5-fluorouracil (5-FU) for advanced hepatocellular carcinoma. However, only little is known about the underlying mechanism of combination therapy. In the present study, we examined whether apoptosis through IFN-α/β receptor (IFN-α/βR) was associated with the effects of combination therapy.

Experimental Design: HuH7, PLC/PRF/5, HLE, and HLF were treated with IFN- (500 units/mL), 5-FU (0.5 μg/mL), or their combination for 10 days. In addition, IFN-α/βR gene transfer with combination therapy was done.

Results: Ten-day treatment by combination therapy resulted in &gt;80% cell growth inhibition. Terminal deoxynucleotidyl transferase–mediated dUTP nick end labeling analysis showed synergistic effects for combination therapy on PLC/PRF/5, HLE, and HLF. Concordant results were obtained with DNA fragmentation. Moreover, there was an evidence showing that changes in the expression of Bcl-2 family lead to apoptosis. On the other hand, the expression of IFN-α/βR and up-regulation of α-phospho–signal transducer and activator of transcription 1, IFN regulatory factor-1 by combination therapy were observed in all cell lines. Furthermore, IFN-α/type 2 IFN receptor long form–transfected HuH7 cells treated with combination therapy showed strong DNA fragmentation compared with nontransfected or transfected with IFN-α- and 5-FU-treated HuH7.

Conclusions: Our results showed that combination of IFN-α plus 5-FU strongly induced cell growth inhibition of human hepatocellular carcinoma cells and indicated that oneof the direct mechanisms of combination therapy may in part be attributable to alterations in induction of apoptosis through IFN-α/βR.

Upregulation of thymidine phosphorylase in rectal cancer tissues by mitomycin C

BACKGROUND AND OBJECTIVES

We have investigated the regulation by mitomycin C (MMC) of thymidine phosphorylase (dThdPase) and dihydropyrimidine dehydrogenase (DPD), which enhances or reduces the efficacy of capecitabine and its metabolite 5'-deoxy-5-fluorouridine (5'-DFUR), in rectal cancer tissues.

MATERIALS AND METHODS

In 31 patients with a rectal cancer, tumor biopsies were performed before and after pre-operative venous administration of 4 mg/m2, 6 mg/m2, or 10 mg/m2 of MMC. The dThdPase and DPD levels in the biopsy and surgical specimens were measured using ELISA, and immunostaining for dThdPase was performed.

RESULTS

The fitting multiple linear regression models indicated that the dThdPase levels increased after MMC administration, in particular in the patients with a pre-treatment dThdPase level less than 56.2 U/mg protein (median value). The time course analysis indicated that the increase in the dThdPase level by 4 mg/m2 of MMC administration continued for 3 weeks. The dThdPase/DPD ratio was increased after MMC administration in patients with a pre-treatment dThdPase/DPD ratio less than 1.79 (median value). MMC enhanced the expression of dThdPase protein both in the tumor cells and in the stromal cells. The disease free-survival rate in the Dukes B or C patients with a high dThdPase/DPD ratio in surgical specimen who received 5'-DFUR based adjuvant chemotherapy tended to be higher than that in those with a low dThdPase/DPD ratio.

CONCLUSION

MMC may upregulate the dThdPase level and the dThdPase/DPD ratio in rectal cancer tissues. Combined use of MMC with capecitabine or 5'-DFUR may offer a more effective colorectal cancer therapy.

Comparative Antitumor Activity of 5-Fluorouracil and 5’-Deoxy-5-Fluorouridine in Combination with Interferon-α in Renal Cell Carcinoma Cell Lines

OBJECTIVES

Although interferon-alpha (IFNalpha) and interleukin-2 are used in the treatment of advanced renal cell carcinoma (RCC), the rate of efficacy is about 15% and not satisfactory. Therefore, a more effective treatment is being investigated. In this study, we examined the combined effects of IFNalpha and 5-fluorouracil (5-FU) as well as 5-deoxy-5-fluorouridine (5'-DFUR), a produrg of 5-FU, in vitro.

MATERIALS AND METHODS

Four RCC cell lines (OCUU1, OCUU3, OCUU4, OCUU5) were established at our laboratory from RCC patients. OS-RC-2, RCC10RGB, TUHR14TKB, TUHR4TKB, A498 and Caki-1 were obtained from a commercial source. The sensitivity of the 10 RCC cell lines to 5-FU and 5'-DFUR was evaluated using MTT assay. The IC50 value for the cytostatics was expressed as the concentration at which growth was inhibited by 50% as compared with the control value. Thymidine phosphorylase (TP), the enzyme that converts 5'-DFUR into 5-FU and 5-FU into FdUMP, was estimated by ELISA.

RESULTS

When the 10 RCC cell lines were divided into the low TP expression group and high TP expression group at 2.0 U/ml protein, TP expression was not enhanced by IFNalpha in all 4 cell lines in the low TP expression group. Antitumor effects were not enhanced by IFNalpha in 3 out of 4 cell lines for 5-FU and in all 4 cell lines for 5'-DFUR. On the other hand, in the high TP expression group, TP expression was enhanced by IFNalpha in 5 out of 6 cell lines, and antitumor effects were enhanced by IFNalpha in 5 out of 6 cell lines for 5-FU and in all 6 cell lines for 5'-DFUR. In addition, there was a significant correlation between TP expression and sensitivity to 5-FU and 5'-DFUR in all RCC cell lines.

CONCLUSIONS

These results suggested that TP may be useful as a predictive factor in combination therapy with IFNalpha and 5-FU or 5'-DFUR, which may be a promising treatment for advanced RCC.

The effect of fluoropyrimidines with or without thymidine phosphorylase inhibitor on the expression of thymidine phosphorylase

Thymidine phosphorylase (platelet-derived-endothelial-cell-growth-factor) catalyzes the reversible phosphorolysis of thymidine to thymine and 2-deoxyribose-1-phosphate, activates 5'-deoxy-5-fluorouridine (5'DFUR) and inactivates trifluorothymidine (TFT). The effect of 5'DFUR and TFT with or without a specific thymidine phosphorylase inhibitor (TPI) on thymidine phosphorylase mRNA, protein expression and activity was studied, in three human colon cancer cell lines, WiDR, HT29 and Lovo exposed for 72 h at IC50 concentrations. In Lovo cells TFT plus TPI only increased thymidine phosphorylase-protein expression 1.7-fold; 5'DFUR and TFT treatment increased thymidine phosphorylase mRNA levels 5- and 1.4-fold, respectively. In WiDR cells, 5'DFUR plus TPI significantly decreased thymidine phosphorylase-protein. TFT and TFT plus TPI increased thymidine phosphorylase-protein 2- and 3-fold, respectively. TPI and 5'DFUR decreased thymidine phosphorylase-mRNA levels significantly. In HT29 cells, 5'DFUR and 5'DFUR plus TPI decreased both thymidine phosphorylase-protein and thymidine phosphorylase-mRNA. In all cell lines 5'DFUR and TFT did not affect thymidine phosphorylase activity, but treatment with TPI (alone or in combination) eliminated thymidine phosphorylase activity. This demonstrated that regulation is drug and cell line dependent.

Potential of interferon-alpha in solid tumours: part 2

The second part of this review examines the use of recombinant interferon-alpha (rIFNalpha) in the following solid tumours: superficial bladder cancer, Kaposi's sarcoma, head and neck cancer, gastrointestinal cancers, lung cancer, mesothelioma and ovarian, breast and cervical malignancies. In superficial bladder cancer, intravesical rIFNalpha has a promising role as second-line therapy in patients resistant or intolerant to intravesical bacille Calmette-Guérin (BCG). In HIV-associated Kaposi's sarcoma, rIFNalpha is active as monotherapy and in combination with antiretroviral agents, especially in patients with CD4 counts >200/mm(3), no prior opportunistic infections and nonvisceral disease. rIFNalpha has shown encouraging results when used in combination with retinoids in the chemoprevention of head and neck squamous cell cancers. It is effective in the chemoprevention of hepatocellular cancer in hepatitis C-seropositive patients. In neuroendocrine tumours, including carcinoid tumour, low-dosage (</=3 MU) or intermediate-dosage (5 to 10 MU) rIFNalpha is indicated as second-line treatment, either with octreotide or alone in patients resistant to somatostatin analogues. Intracavitary IFNalpha may be useful in malignant pleural effusions from mesothelioma. Similarly, intraperitoneal IFNalpha may have a role in the treatment of minimal residual disease in ovarian cancer. In breast cancer, the only possible role for IFNalpha appears to be intralesional administration for resistant disease. IFNalpha may have a role as a radiosensitising agent for the treatment of cervical cancer; however, this requires confirmation in randomised trials. On the basis of current evidence, the routine use of rIFNalpha is not recommended in the therapy of head and neck squamous cell cancers, upper gastrointestinal tract, colorectal and lung cancers, or mesothelioma. Pegylated IFNalpha (peginterferon-alpha) is an exciting development that offers theoretical advantages of increased efficacy, reduced toxicity and improved compliance. Further data from randomised studies in solid tumours are needed where rIFNalpha has activity, such as neuroendocrine tumours, minimal residual disease in ovarian cancer, and cervical cancer. A better understanding of the biological mechanisms that determine response to rIFNalpha is needed. Studies of IFNalpha-stimulated gene expression, which are now feasible, should help to identify molecular predictors of response and allow us to target therapy more selectively to patients with solid tumours responsive to IFNalpha.

Upregulated hypoxia inducible factor-1alpha and -2alpha pathway in rheumatoid arthritis and osteoarthritis

The pathogenesis of rheumatoid arthritis (RA) and osteoarthritis (OA) remains obscure, although angiogenesis appears to play an important role. We recently confirmed an overexpression of two angiogenic factors, namely vascular endothelial growth factor (VEGF) and platelet-derived endothelial cell growth factor (PD-ECGF), by the lining and stromal cells of the synovium in both conditions. Because hypoxia inducible factor (HIF)-1alpha and HIF-2alpha are essential in regulating transcription of the VEGF gene, active participation of HIF-alpha molecules in the pathogenesis of these arthritides is anticipated. We investigated the immunohistochemical expression of HIF-1alpha and HIF-2alpha in the synovium of 22 patients with RA, 34 patients with OA and 22 'normal' nonarthritic individuals, in relation to VEGF, VEGF/KDR (kinase insert domain protein receptor) vascular activation, PD-ECGF and bcl-2. A significant cytoplasmic and nuclear overexpression of HIF-1alpha and HIF-2alpha was noted in the synovial lining and stromal cells of both diseases relative to normal. Overexpression of HIF-alphas was related to high microvessel density, high PD-ECGF expression and high VEGF/KDR receptor activation, suggesting HIF-alpha-dependent synovial angiogenesis in OA. By contrast, the activation of the angiogenic VEGF/KDR pathway was persistently increased in RA, as indeed was microvessel density and the expression of PD-ECGF, irrespective of the extent of HIF-alpha expression, indicating a cytokine-dependent angiogenesis. In all cases, the VEGF/KDR vascular activation was significantly lower in OA than in RA, suggesting a relative failure of the HIF-alpha pathway to effectively produce a viable vasculature for OA, which is consistent with the degenerative nature of the disease. The activation of the HIF-alpha pathway occurs in both RA and OA, although for unrelated reasons.

Interleukin-2 Based Therapy for Kidney Cancer

In summary, IL-2 based therapy remains the basis for treatment of metastatic renal cell cancer. Un-answered questions remain in the development of regimens that exceed a mean response rate of 20%. Additionally, there may be differences among the histologic subtypes of renal cell cancer that predispose to response or lack there of to immunotherapy, and this is being further explored. As can be noted from the studies presented in this paper, there are numerous variations on the regimens for IL-2 based therapy. Current recommendations are to use the simplest and most feasible in a given institution. Certainly high dose IL-2 remains the standard regimen to which all others are measured.

Randomized phase II trial of embolization therapy versus chemoembolization therapy in previously treated patients with colorectal carcinoma metastatic to the liver

Locoregional therapies are useful in treating patients with colorectal cancer metastatic to the liver. A prospective randomized phase II trial of hepatic artery embolization versus hepatic artery chemoembolization was conducted to evaluate the response rates and toxicities of these therapies in the second-line setting. Patients were required to have biopsy-proven adenocarcinoma of the colon or rectum metastatic to the liver, with the liver as the sole or predominant site of metastatic disease. All patients had measurable disease and had failed at least one prior systemic chemotherapy treatment for metastatic disease. Patients were randomized to receive either embolization therapy with polyvinyl alcohol foam (Ivalon) administered as a single agent or chemoembolization using polyvinyl alcohol foam mixed with 750 mg/m2 of 5-fluorouracil and 9 million units of interferon. Drugs and embolic material were administered via the hepatic artery as a slurry with polyvinyl alcohol foam. Fifty eligible patients were enrolled. There were 24 patients in the chemoembolization arm and 26 in the embolization arm. Sixty-four percent of patients in both treatment arms had the liver as the sole metastatic site. The most common National Cancer Institute common toxicity criteria grade 3/4 toxicities were diarrhea (17%) and hepatic toxicity (8%). There was 1 (4%) treatment-related mortality due to a hepatic abscess. Four patients (15.4%) treated with embolization had a partial response (PR), and 5 patients (20.8%) treated with chemoembolization had a PR. The median survival for all patients was 11 months (95% confidence interval [CI], 8-15 months). Survival in patients with extrahepatic disease was 8 months (95% CI, 6-10 months). Survival in patients with liver-only metastases was 15 months (95% CI, 10-17 months). Embolization of the liver as second-line therapy in patients with liver-predominant metastases is safe and effective. Median survivals are comparable to other second-line therapies

Thymidine phosphorylase expression in normal, hyperplastic and neoplastic prostates: correlation with tumour associated macrophages, infiltrating lymphocytes, and angiogenesis

Thymidine phosphorylase is an angiogenic factor primarily expressed by cancer cells, stromal cells and tumour-associated macrophages in many human malignancies. These different types of thymidine phosphorylase-expressing cells, however, may have a distinct place in the angiogenic process, and this question was addressed in the present study. A series of 20 normal/hyperplastic prostate glands and 60 prostate carcinomas was investigated by immunohistochemistry, using specific antibodies for thymidine phosphorylase (P-GF.44C), tumour-associated macrophages (CD68), endothelium (CD31) and prostate specific antigen (ER-PR8). Thymidine phosphorylase expression by normal and hyperplastic epithelial or stromal cells occurred almost exclusively in the context of an intense lymphocytic infiltrate. High thymidine phosphorylase cancer cells and thymidine phosphorylase stromal cells expression was associated with high angiogenesis in prostate carcinomas, and this significant association was extended to include both tumour-associated macrophages and tumour-infiltrating lymphocytes. Thymidine phosphorylase expression and tumour-infiltrating lymphocytes were related inversely with prostate specific antigen reactivity. In conclusion, thymidine phosphorylase is a major angiogenic factor in prostate carcinomas and its up-regulation is likely to occur in the context of a host immune response.

Prognostic value of thymidine phosphorylase expression in breast carcinoma

Thymidine phosphorylase (TP), also known as platelet-derived endothelial cell growth factor (PD-ECGF), is an enzyme that catalyzes the reversible dephosphorylation of thymidine, deoxyuridine and their analogs. TP has also angiogenic properties, although the precise mechanism by which it promotes angiogenesis is not known. We examined TP expression using immunohistochemistry (654-1 Mab) in 182 invasive breast carcinomas (67 N0 and 115 N1/2; median follow-up 78 months [range, 3-177]; 51 patients treated with adjuvant systemic cyclophosphamide, methotrexate and 5-fluorouracil [CMF] chemotherapy and 82 with tamoxifen). High TP expression was found in 142 cases (78%) and correlated with lower histologic grade and low p53 expression. No correlation was found between TP expression and vascular density. TP-positive tumors had a significant increase in both disease-free survival (DFS; p = 0.0025) and overall survival (OS; p = 0.0070) in the total cohort of patients and in the subgroups of node-positive patients and patients treated with CMF adjuvant therapy; no significant difference in either DFS or OS was observed in patients without CMF treatment. Our findings suggest that TP has little effect on tumor angiogenesis of breast carcinoma, whereas it could represent an interesting marker that could predict response to CMF chemotherapy.

Combined intraarterial 5-fluorouracil and subcutaneous interferon-alpha therapy for advanced hepatocellular carcinoma with tumor thrombi in the major portal branches

BACKGROUND

The prognosis of hepatocellular carcinoma (HCC) invading into the major branches of the portal vein (Vp3) is extremely poor.

METHODS

Eleven consecutive patients with HCC and Vp3 were treated with 2-6 cycles of a "basic" combination therapy consisting of continuous arterial infusion of 5-fluorouracil (450-500 mg/day, for the initial 2 weeks) and subcutaneous injection of interferon-alpha (5 million international units, 3 times/week, 4 weeks). In the first 3 patients, methotrexate (90 mg/day 1 of every week), cisplatin (10 mg/day), and leucovorin (30 mg/days 2 and 3 of every week) also were administered for the initial 2 weeks ("full" regimen).

RESULTS

In 8 (73%) of 11 patients, an objective response (complete response [CR] or partial response [PR]) was observed with marked regression of tumor and decrease in tumor markers. The use of the full regimen was associated with objective response in all patients; instead, they developed thrombocytopenia or leukopenia. In the subsequent 8 patients with basic regimen, 5 patients showed CR (2 cases) or PR (3 cases; objective response rate, 63%), and leukopenia was observed only in 1 patient.

CONCLUSIONS

Simple combination therapy with subcutaneous interferon-alpha and intraarterial 5-fluorouracil therefore is a promising treatment modality for intractable HCC with Vp3.

Structural analyses reveal two distinct families of nucleoside phosphorylases

The reversible phosphorolysis of purine and pyrimidine nucleosides is an important biochemical reaction in the salvage pathway, which provides an alternative to the de novo purine and pyrimidine biosynthetic pathways. Structural studies in our laboratory and by others have revealed that only two folds exist that catalyse the phosphorolysis of all nucleosides, and provide the basis for defining two families of nucleoside phosphorylases. The first family (nucleoside phosphorylase-I) includes enzymes that share a common single-domain subunit, with either a trimeric or a hexameric quaternary structure, and accept a range of both purine and pyrimidine nucleoside substrates. Despite differences in substrate specificity, amino acid sequence and quaternary structure, all members of this family share a characteristic subunit topology. We have also carried out a sequence motif study that identified regions of the common subunit fold that are functionally significant in differentiating the various members of the nucleoside phosphorylase-I family. Although the substrate-binding sites are arranged similarly for all members of the nucleoside phosphorylase-I family, a comparison of the active sites from the known structures of this family indicates significant differences between the trimeric and hexameric family members. Sequence comparisons also suggest structural identity between the nucleoside phosphorylase-I family and both 5'-methylthioadenosine/S-adenosylhomocysteine nucleosidase and AMP nucleosidase. Members of the second family of nucleoside phosphorylases (nucleoside phosphorylase-II) share a common two-domain subunit fold and a dimeric quaternary structure, share a significant level of sequence identity (>30%) and are specific for pyrimidine nucleosides. Members of this second family accept both thymidine and uridine substrates in lower organisms, but are specific for thymidine in mammals and other higher organisms. A possible relationship between nucleoside phosphorylase-II and anthranilate phosphoribosyltransferase has been identified through sequence comparisons. Initial studies in our laboratory suggested that members of the nucleoside phosphorylase-II family require significant domain movements in order for catalysis to proceed. A series of recent structures has confirmed our hypothesis and provided details of these conformational changes. Structural studies of the nucleoside phosphorylases have resulted in a wealth of information that begins to address fundamental biological questions, such as how Nature makes use of the intricate relationships between structure and function, and how biological processes have evolved over time. In addition, the therapeutic potential of suppressing the nucleoside phosphorylase activity in either family of enzymes has motivated efforts to design potent inhibitors. Several research groups have synthesized a variety of nucleoside phosphorylase inhibitors that are at various stages of preclinical and clinical evaluation.

Molecular markers predictive of response to chemotherapy in gastrointestinal tumors

Gastrointestinal cancers account for a large amount of human tumors. Surgery is the standard treatment for localized gastrointestinal cancer, but in a large number of patients, tumors are unresectable at time of diagnosis and even when resectable, survival is often poor. Current attempts to improve these results include the use of chemotherapy in the adjuvant setting, in the advanced disease, or as neoadjuvant treatment. However, less than half the patients respond to chemotherapeutic treatments, mostly reporting important side-effects. The identification of molecular markers, such as p53, thymidylate synthase, K-ras, and others, may provide an important tool for medical oncologists in defining subsets of patients with gastrointestinal cancers more suitable to benefit from chemotherapy or from experimental therapies. The relationship between the clinical outcome to anticancer drugs and molecular markers in gastrointestinal tumors has been reviewed. Available data are promising, but most of them arise from retrospective and small studies. Well designed, prospective trials are warranted to change the target approach from a general to an individual treatment strategy.

Advances in the treatment of metastatic colorectal cancer

Colorectal cancer represents the third leading cause of cancer mortality in the United States. During the past four decades, 5-fluorouracil (5-FU) has served as the cornerstone of therapy for individuals with advanced colorectal cancer (ACRC). Despite numerous attempts at maximizing efficacy of 5-FU through biochemical modulation, a significant benefit in terms of survival has never been realized. The recent emergence of novel chemotherapeutic drugs employing different mechanisms of action than 5-FU has led to the incorporation of irinotecan (CPT-11) with 5-FU/leucovorin as the new standard first-line regimen for future trials. This review outlines emerging data utilizing oral fluoropyrimidines and other new agents including oxaliplatin, raltitrexed, and eniluracil. Randomized clinical trials are currently underway in an effort to define optimal combination chemotherapy regimens, scheduling of agents, duration of therapy, and choice of therapy using a variety of prognostic molecular markers.

Enhancement of sensitivity to capecitabine in human renal carcinoma cells transfected with thymidine phosphorylase cDNA

The purpose of the present study was to examine directly the role of thymidine phosphorylase (TP) in the sensitivity of renal cell carcinoma (RCC) to a novel fluoropyrimidine carbamate, capecitabine. TP cDNA-transfected RCC are used in these experiments to provide a basis for improved therapeutic benefit in chemoimmunotherapy. Human RCC line KU2 cells were transfected with pcDNA3.1/zeo(+) with or without human TP cDNA by the lipofectin method. We established a clone transfected with pcDNA3.1/zeo(+)/TP (KU2-TP15) and a clone transfected with pcDNA3.1/zeo(+) as a control (KU2-C1). TP expression levels (mean +/- SD) examined by enzyme-linked immunosorbent assay (ELISA) were 1.3 +/- 0.14 U/mg protein in KU2, 1.6 +/- 0.57 U/mg protein in KU2-C1 and 216 +/- 25.6 U/mg protein in KU2-TP15. Immunohistochemical staining of subcutaneous tumors established in Balb/c nu/nu mice showed that KU2-TP15 was strongly positive for TP expression, whereas KU2 and KU2-C1 were negative. Sensitivities in vitro to 5-fluorouracil (5FU), 5'-deoxy-5-fluorouridine (5'DFUR) and capecitabine in KU2-TP15 were significantly enhanced compared with those in KU2 or KU2-C1. A moderate but statistically significant bystander effect was observed in vitro. KU2-TP15 tumors showed significant increase in the in vivo sensitivities to 5'DFUR and capecitabine as compared with the vehicle alone while KU2-C1 tumors did not. The difference in tumor-free rate in mice bearing KU2-TP15 at 2 months after the cessation of treatment was statistically significant between the capecitabine treatment group and the controls, the 5FU treatment group and the 5'DFUR treatment group. The present study clearly provides direct evidence for the role of TP in mediating the sensitivity of RCC to capecitabine.

Fluorouracil modulation in colorectal cancer: lack of improvement with N -phosphonoacetyl- l -aspartic acid or oral leucovorin or interferon, but enhanced therapeutic index with weekly 24-hour infusion schedule--an Eastern Cooperative Oncology Group/Cancer and Leukemia Group B Study

PURPOSE

To investigate mechanism-directed regimens in maximizing the efficacy of fluorouracil (5-FU) in advanced colorected cancer.

PATIENTS AND METHODS

Based on promising phase II data, a randomized comparison of various methods for the biochemical modulation of 5-FU was undertaken in patients with advanced colorectal cancer. The control group received single-agent 5-FU as a 24-hour infusion weekly. Patients (N = 1,120) with no prior chemotherapy for metastatic disease were randomized to one of the following arms: arm A, 5-FU 2,600 mg/m2 by 24-hour infusion, weekly; arm B, N-phosphonoacetyl-l-aspartic acid 250 mg/m2 day l, 5-FU 2,600 mg/m2 by 24-hour infusion day 2, weekly; arm C, 5-FU 600 mg/m2 with oral leucovorin (LV) 125 mg/m2 hourly for the preceding 4 hours, weekly; arm D, 5-FU 600 mg/m2 with intravenous (IV) LV 600 mg/m2, weekly; arm E, 5-FU 750 mg/m2/d IV by continuous infusion for 5 days, then 750 mg/m2 weekly, and recombinant interferon alfa-2a 9 million units subcutaneously three times weekly. Median follow-up was 4.8 years.

RESULTS

Of the 1,098 assessable patients, 57% had measurable disease. The toxicity of all the regimens was tolerable. Grade 4 or worse toxicity occurred in 11%, 11%, 30%, 24%, and 22% on each arm, respectively; diarrhea was the most common adverse effect. These toxicity patterns favored significantly (P <.001) the 24-hour infusion arms. Median survival (months) by arm was A, 14.8; B, 11.9; C, 13.5; D, 13.6; and E, 15.2. These survival durations did not differ significantly.

CONCLUSION

We conclude that a weekly infusion regimen of 5-FU is significantly less toxic than and as effective as 5-FU bolus regimens modulated by either LV or interferon in patients with metastatic colorectal cancer.

Regulation of dihydropyrimidine dehydrogenase and pyrimidine nucleoside phosphorylase activities by growth factors and subsequent effects on 5-fluorouracil sensitivity in tumor cells

Dihydropyrimidine dehydrogenase (DPD) and pyrimidine nucleoside phosphorylase (PyNPase) are the first and rate-limiting enzymes that regulate 5-fluorouracil (5-FU) metabolism, and tumoral DPD activity appears to be a promising predictor of 5-FU sensitivity. However, the regulatory mechanisms determining these enzyme activities have not been fully understood. We investigated the biological effects of epidermal growth factor (EGF) and transforming growth factor (TGF)-alpha on cell growth and tumoral DPD and PyNPase activities, and the subsequent effects on 5-FU sensitivity in uterine cervical carcinoma SKG-IIIb cells. The treatment of tumor cells with EGF or TGF-alpha resulted in a concentration-dependent increase in tumor cell growth and PyNPase activity, whereas tumoral DPD activity was inhibited. Their stimulatory effects on tumor cell growth correlated well with PyNPase activity, but were inversely related to DPD activity (P < 0.01). 5-FU sensitivity of tumor cells increased in the presence of EGF or TGF-alpha. These growth factors were shown to stimulate the first, rate-limiting enzyme activity in 5-FU anabolism and to inhibit that in 5-FU catabolism, leading to enhancement of the antiproliferative action of 5-FU at achievable therapeutic levels. The tumor environmental factors, EGF and TGF-alpha, may act as intrinsic regulators of DPD and PyNPase activities that affect the 5-FU sensitivity of individual tumors.

Chemo-biotherapy with 5-fluorouracil, leucovorin, and alpha interferon in metastatic carcinoma of the colon--a Cancer Biotherapy Research Group [CBRG] phase II study

BACKGROUND

Biochemical modulation of 5-Fluorouracil activity with Leucovorin has been well documented in colorectal cancer. Several studies have shown increased efficacy of 5-fluorouracil in combination with alpha interferon. We therefore initiated a phase II trial of dual modulation of 5-fluorouracil with leucovorin and alpha interferon to evaluate outcomes in patients with metastatic carcinoma of the colon.

METHODS

Patients with metastatic colon carcinoma with expected survival > 4 months and performance status of ECOG < or = 2 were treated weekly with Leucovorin 400 mg i.v. followed by 5-FU 600 mg/m2 i.v. bolus. Alpha interferon 3-9 million units was administered subcutaneously every Monday, Wednesday and Friday. Patients were analyzed for toxicity, tumor response and survival.

RESULTS

Sixteen patients with a median age of 66 years were treated. Three patients were not evaluable for response but were evaluable for toxicity. Grades 3 and 4 toxicities were neutropenia, diarrhea, mucositis, nausea and vomiting, fatigue, fever, asthenia and elevated hepatic enzymes. One patient died from complications associated with diverticulitis and neutropenia. Objective response rate was 23% (95% confidence interval 4-46%) and median survival was 11.5 months (95% confidence interval 6.3-19 months). Thirty-eight percent of the patients were alive at one year and 19% at two years.

CONCLUSION

The combination of 5-fluorouracil, leucovorin and alpha interferon as administered in this phase II study did not result in enhanced response rate or survival. However this regimen was associated with considerable toxicity.

Augmentation of antitumor activity of 5'-deoxy-5-fluorouridine by thymosin fraction 5 in mouse bladder cancer cells in vitro and in vivo

5'-Deoxy-5-fluorouridine (5'-dFUrd) is a prodrug of 5-fluorouracil (5-FUra) activated by pyrimidine nucleoside phosphorylase (PyN Pase), mainly by uridine phosphorylase (Urd Pase) in rodents and by thymidine phosphorylase (TdR Pase) in humans, which is preferentially located in tumor tissues compared to normal tissues. It has been reported that PyN Pase is induced by cytokines such as tumor necrosis factor (TNF), interleukin-1alpha (IL-1alpha) and interferon (IFN). Thymosin is a glycoprotein extract obtained from the calf thymus and is a potent immunopotentiating preparation. In this study, the antiproliferative activity of 5'-dFUrd used in combination with thymosin fraction 5 (TF5) was investigated in mouse bladder cancer cell line MBT-2 in vitro and in vivo. In vitro TF5 enhanced the activity of 5'-dFUrd by up to 4.11-fold, whereas the activity of other cytostatics such as 5-FUra, mitomycin C, adriamycin, cis-platinum, etoposide, vinblastine and methotrexate was not changed. In vivo when the effects of combination therapy with 5'-dFUrd and TF5 in C3H/HeN mice implanted with MBT2 were studied, tumor growth was not suppressed by TF5 alone while tumor growth was suppressed to some degree by 5'-dFUrd alone. However, tumor growth suppression was enhanced when 5'-dFUrd was used in combination with TF5. In order to investigate this mechanism, Urd Pase in MB2 was measured, and it was found that TF5 increased enzyme activity by up to 1.8-fold in MBT2. This increased susceptibility might be a result of the induction of Urd Pase, which is the essential enzyme for the conversion of 5'-dFUrd to 5-FUra. These results suggested that the therapeutic benefit of 5'-dFUrd would be improved by its use in combination with TF5 and the modulation of converting enzymes for antitumor prodrugs could be a novel therapeutic strategy for treating human cancers.

Sequential biochemical modulation of fluorouracil with folinic acid, N-phosphonacetyl-L-aspartic acid, and interferon alfa-2a in advanced colorectal cancer

PURPOSE

Several agents have been evaluated for their effect as biochemical modulators of fluorouracil (5-FU) in the treatment of metastatic colorectal carcinoma. In this study, we used folinic acid (FA), N-phosphonacetyl-L-aspartic acid (PALA), and recombinant interferon alfa-2a (IFNalpha-2a) in a sequential order to assess the efficacy of this approach in patients with metastatic colorectal carcinoma.

PATIENTS AND METHODS

Forty-four patients with metastatic colorectal carcinoma were enrolled onto the study. The treatment course consisted of three cycles: (cycle 1) FA 20 mg/m(2) followed by 5-FU 425 mg/m(2) on days 1 to 5; (cycle 2) PALA 250 mg/m(2) on days 29, 36, 43, and 50 and 5-FU 2,600 mg/m(2) as a 24-hour infusion on days 30, 37, 44, and 51; and (cycle 3) IFNalpha-2a 9 million units (MU) three times a week for 5 weeks beginning on day 57, with a continuous infusion of 5-FU 750 mg/m(2) on days 57 to 61, and then weekly bolus of 5-FU 750 mg/m(2)/wk on days 71, 78, and 85. Response was determined after cycle 3.

RESULTS

All patients had a Zubrod performance status >/= 2, measurable disease, and had received no prior chemotherapy for their metastatic disease. A total of 212 cycles were given. Thirty-six patients were assessable for response. No complete responses were seen. Seven patients had a partial response, eight had stable disease, and 15 had progressive disease. The median duration of response was 25 weeks, and the median survival was 53 weeks. Grade 3 and 4 toxic effects included granulocytopenia, stomatitis, diarrhea, rash, nausea, and fatigue.

CONCLUSION

This trial provided no evidence that sequential biochemical modulation of 5-FU in patients with metastatic colorectal carcinoma had any therapeutic advantage over conventional treatment regimens of 5-FU plus FA.

Durable clinical and pathologic response of hepatocellular carcinoma to systemic and hepatic arterial administration of platinol, recombinant interferon alpha 2B, doxorubicin, and 5-fluorouracil: a communication

The case described here illustrates the antitumor activity of a four-drug systemic combination chemobiotherapy with platinol, recombinant interferon alpha 2b, doxorubicin (Adriamycin), and 5-fluorouracil (5-FU) (PIAF) in a patient with diffuse hepatocellular carcinoma involving the liver and lungs.

Pilot trial of infusional 5-fluorouracil, interleukin-2, and subcutaneous interferon-alpha for advanced renal cell carcinoma

The authors developed an outpatient, three-drug combination regimen for advanced renal cell carcinoma. Treatment was administered for 5 days each week for 4 weeks, followed by 2-week rests. Each weekly treatment consisted of 5-fluorouracil 1,750 mg/m2 continuous intravenous infusion for 24 hours followed by interleukin-2 6 mIU/m2 per day continuous intravenous infusion for 4 days, and interferon-alpha2b 6 mU/m2 subcutaneously on days 1, 2, and 5. This trial was undertaken to assess tolerability to this regimen and obtain a preliminary assessment of its effectiveness. Most patients required some dose adjustments (especially of cytokines), treatment interruptions, or both. Toxicities were as would be expected from individual drug profiles with only mild to moderate hematologic toxicities. Among 16 patients with renal cell carcinoma treated, four had major (clinical partial response) responses, one of which was demonstrated to be a pathologic clinical response after surgical resection of a residual mass. Estimated median survival time of all patients was 93 weeks. Response and survival were correlated with known clinical risk factors. Responding patients were noted to be significantly older in age (X = 61.75 years) than nonresponders (X = 48.92 years). There was no correlation between age and other clinical risk factors, treatment tolerance, or survival. The authors conclude that this three-drug regimen is a practical, tolerable, and promising regimen for further study in renal cell carcinoma.

The crystal structure of pyrimidine nucleoside phosphorylase in a closed conformation

BACKGROUND

Pyrimidine nucleoside phosphorylase (PYNP) catalyzes the reversible phosphorolysis of pyrimidines in the nucleotide synthesis salvage pathway. In lower organisms (e.g. Bacillus stearothermophilus) PYNP accepts both thymidine and uridine, whereas in mammalian and other higher organisms it is specific for thymidine (designated thymidine phosphorylase, TP). PYNP shares 40% sequence similarity (and presumably significant structural similarity) with human TP, which has been implicated as a growth factor in tumor angiogenesis. It is thought that TP undergoes a major conformational change upon substrate binding that consequently produces an active conformation.

RESULTS

The crystal structure of PYNP from B. stearothermophilus with the substrate analog pseudouridine in its active site has been solved to 2.1 A resolution. This structure confirms the similarity of PYNP to TP and supports the idea of a closed active conformation, which is the result of rigid body movement of the alpha and alpha/beta domains. The active-site cleft, where the pyrimidine and phosphate substrates bind, is between the two domains. The structure reveals an asymmetric dimer in which one subunit is fully closed and the other is only partially closed.

CONCLUSIONS

The closed conformation of PYNP serves as a good model to better understand the domain movement and overall function of TP. Active-site residues are confirmed and a possible mechanism for substrate binding and subsequent domain movement is suggested. Potent inhibitors of TP might have significant therapeutic value in various chemotherapeutic strategies, and the structure of PYNP should provide valuable insight into the rational design of such inhibitors.

5-fluorouracil: a pharmacological paradigm in the use of cytotoxics

1. Painstaking progress in drug development is well illustrated by 5-fluorouracil (5FU), originally designed 40 years ago as a fluorinated analogue of the naturally occurring base uracil. Innovative pharmacokinetic and pharmacodynamic strategies have seen significant clinical improvements for cancer patients over the past decade. 2. 5-Fluorouracil acts by three main mechanisms. Principally, the intermediate metabolite fluorodeoxyuridine monophosphate inhibits a key enzyme in pyrimidine biosynthesis, namely thymidylate synthase (TS). Additionally, 5FU is metabolized to ribo- and deoxy-ribonucleotides, which act as false bases for incorporation into RNA and DNA. 3. Biomodulation of 5FU has been attempted with methotrexate (MTX), folinic acid, interferons, cisplatin and radiotherapy. Methotrexate augments the actions of 5FU by inhibiting dihydrofolate reductase and decreasing the folate pool required for pyrimidine biosynthesis, inhibiting TS via MTX-polyglutamate and directly inhibiting purine biosynthesis. Interferons increase steady state concentrations of 5FU. 5-Fluorouracil enhances the cytotoxicity of cisplatin and radiotherapy by inhibiting DNA repair. Folinic acid enhances TS inhibition by increasing the intracellular pool of folates that stabilize the 5FU-TS complex. 4. 5-Fluorouracil has a short plasma half-life. Thymidylate synthase inhibition is limited to the S-phase of the cell cycle and only a small fraction of most cancer cells are in S-phase at any one time. Increased response rates seen with infusional protocols may reflect the effective recruitment of additional mechanisms of cytotoxicity, not dependent on cell cycle, including effects on RNA synthesis. 5. Patients with localized metastatic disease may benefit from locoregional treatments. These include hepatic intra-arterial therapy with related compounds, such as floxuridine, which reach high concentrations at sites of tumour, while systemic toxicities are minimized by efficient hepatic clearance. 6. Recent developments include orally bioavailable formulations, such as ftorafur, capecitabine and the combination of 5FU with the dihydropyrimidine phosphate dehydrogenase inhibitor ethynyluracil. Recognition of diurnal variation in the activity of such key enzymes as DPD has led to the administration of 5FU at regulated, variable infusion rates (chronomodulation). These promising pharmacological approaches may further improve clinical outcomes in common cancers.