Interferon alpha-2a shows antitumor activity in combination with 5-fluorouracil against human colon carcinoma xenografts: A study in reference to thymidylate synthetase activity inhibition

To clarify the mode of antitumor activity shown by a combination of recombinant human interferon alpha-2a (IFN) and 5-fluorouracil (5-FU), experimental therapy was performed on human colon carcinoma (Co-4) xenografts serially transplanted into nude mice, using IFN and 5-FU, either alone or in combination. IFN alone showed dose-dependent antitumor activity and 5-FU also revealed a moderate antitumor effect. Although IFN, given as 600,000 units/mouse daily sc×14, and 5-FU, given as 60 mg/kg q4d×3 ip, showed additive antitumor activity against Co-4, the thymidylate synthetase (TS) inhibition rate was unchanged in the tumors treated with the IFN/5-FU combination in comparison with those treated with 5-FU alone. This suggests that the antitumor activity of IFN and 5-FU in combination does not involve augmentation of the TS inhibition by 5-FU.     

Biochemical Modulation of 5-Fluorouracil with Murine Interferon-α/β Against Murine Renal Cell Carcinoma

Department of Urology, School of Medicine, Keio University, Tokyo, Japan
Background Conventional therapy for renal cell carcinoma using interferon (IFN) has shown limited antitumor action. The purpose of our study was to investigate synergistic antitumor effects of IFN and 5-fluorouracil (5-FU), and to elucidate the mechanisms of interaction between the 2 agents in mice.
Methods Antitumor effects and biochemical modulation of murine IFN-α/β and 5-FU were determined against the murine renal cell carcinoma cell line, Renca, in vivo. The activity of thymidylate synthetase and thymidine kinase was measured using cytosolic extracts of the tumors.
Results Combination treatment with IFN-α/β and 5-FU produced a significant enhancement of growth inhibition against Renca tumor. Treatment with 5-FU resulted in a 2.7-fold increase in the total amount of thymidylate synthetase and an 11.6-fold increase in the thymidylate synthetase inhibition rate, while the administration of IFN-α/β did not significantly reduce the 5-FU-induced increase in thymidylate synthetase. The administration of IFN-α/β decreased thymidine kinase activity to 65.5% maximally, compared with that in the control mice or the mice treated with 5-FU.
Conclusions The reduction of thymidine kinase caused by treating the mice with IFN-α/β changes the utilization of exogenous thymidine for DNA synthesis, and may represent the mechanism of the additive antitumor effect of the 2 agents, through the suppression of the salvage pathway for deoxythymidine monophosphate induction.     

The modulating effect of interferon alpha-2a on the antitumor activity of UFT against a human gastric carcinoma xenograft,SC-1-NU,in nude mice

The modulating effect of recombinant human interferon alpha-2a (IFN) on the antitumor activity of UFT, a mixed compound of tegafur and uracil at a molar ratio of 1:4, was investigated against SC-1-NU, a human gastric cancer xenograft serially transplanted in nude mice. IFN was administered subcutaneously at a dose of 60,000 IU/mouse daily for 14 days, and UFT was given at a dose of 15 mg/kg as tegafur daily, except on Sundays, for 3 weeks. The agents were administered either alone or simultaneously. Synergistic antitumor activity on SC-1-NU was produced by the combination of IFN and UFT without any increment of side effects, and the combination therapy also increased intratumoral thymidylate synthetase (TS) inhibition and the amount of 5-fluorouracil (5-FU) in the intratumoral RNA. Thus, IFN seems to modulate the antitumor activity of UFT against SC-1-NU through an inhibition of DNA synthesis and RNA distortion, and therefore this combination could be useful for clinical application.     

Neurologic toxicity associated with interferon α therapy for renal cell carcinoma

A 67-year-old man received interferon alpha (IFN alpha) therapy for lung metastases of renal cell carcinoma (RCC). Multiple pulmonary metastases disappeared completely. However, neurological toxicity was detected by magnetic resonance imaging (MRI) as abnormal brain lesions. After discontinuation of IFN alpha therapy, his neurological symptoms and abnormal lesions on MRI disappeared completely. Complete remission of RCC has continued, and results of neurological study have remained normal for 5 years after discontinuation of IFN alpha therapy.     

The in vitro assessment of various types of interferons for urological tumors by the human tumor clonogenic assay

The direct antitumor effects of various types of interferons (IFNs) were compared against urological malignancies, in particular the renal tumor using the human tumor clonogenic assay (HTCA). The concentrations of each IFN were 50 and 500 IU/ml, respectively, and the exposure time was continuous (2-4 weeks). IFN alpha A, beta, gamma, (recombinant type) and alpha (human lymphoblastoid type) were investigated in 37 specimens of urological primary tumors. Each tumor was judged to be sensitive to IFN by 70% colony inhibition when compared to the colonies of the controls. Eight (22%) of the 36 trials were sensitive to IFN. On the other hand, 3 cases (8%) were augmented cases defined as a colony increase of more than two times the standard error of control colony growth. The renal tumor had a tendency to be more sensitive to IFN than the other urological tumors (P less than 0.1). The order of the colony inhibition against the renal tumor was IFN gamma greater than alpha greater than alpha A, beta. This order was statistically significant (P less than 0.025, Wilcoxon's test). These results corresponded with the results reported by others. We recommend the HTCA as an adequate method for assessing the direct antitumor effect of IFN.     

Inhibition of mouse bladder tumor proliferation by alpha difluoromethylornithine and interferon in vitro and in vivo

Previous studies have reported that alpha difluoromethylornithine (DFMO), an enzyme-activated, irreversible inhibitor of ornithine decarboxylase (ODC), has anti-tumor activity in several tumor systems. Recently, investigations have revealed that combinations of DFMO and Interferon (IFN) are synergistic in inhibiting tumor cell growth. We tested the effects of DFMO and IFN alpha, beta alone and in combination on the growth of mouse bladder tumor (MBT-2) cells both in vitro and in vivo. MBT-2 cells were incubated for 72 hours in 96 well microtiter plates with DFMO, IFN alpha, beta and combinations of both agents and percentage inhibition was calculated. In vivo studies utilized the intravesical implantation method as well as subcutaneous implantation. DFMO was administered as a 1% solution in the drinking water. IFN alpha, beta was given bi-weekly by intravesical administration. DFMO effectively inhibited MBT-2 growth in vitro. The ID50 was 0.08 mM and peak inhibitory activity was reached at concentrations of 0.16 mM and remained constant with concentrations of up to 10 mM. IFN alpha, beta also inhibited the in vitro proliferation of MBT-2 with maximum inhibition (46%) at 2,000 U/ml. Combinations of DFMO and IFN alpha, beta showed increased anti-proliferative activity. The degree of enhancement varied with synergism, additivity, or sub-additivity at varying drug concentrations. In vivo, DFMO significantly retarded the growth of tumors implanted subcutaneously (p less than .05) and significantly delayed the outgrowth of tumors implanted intravesically (p less than .01). IFN alpha, beta alone was ineffective in vivo and produced no additive effect in vivo when used in combination with DFMO. Results of our investigation show that DFMO inhibits proliferation of MBT-2 cells in vitro and exhibits a similar effect in vivo against subcutaneous and intravesical tumor implants. IFN alpha, beta alone demonstrated anti-proliferative activity in vitro but did not affect MBT-2 growth in vivo. Although the combination of DFMO and IFN alpha, beta exhibited enhanced activity in vitro, no enhancement was observed with combination therapy in vivo.     

PTK787/ZK222584 Combined with Interferon Alpha and 5-Fluorouracil Synergistically Inhibits VEGF Signaling Pathway in Hepatocellular Carcinoma

Background

The prognosis of patients with hepatocellular carcinoma (HCC) and portal vein tumor thrombus remains poor. We previously reported the beneficial effects of interferon alpha (IFN) and 5-fluorouracil (5-FU) combination therapy for these patients. We showed that the mechanism of therapy was regulation of vascular endothelial growth factor (VEGF). Here, we combined IFN/5-FU therapy with the VEGF receptor–selective inhibitor PTK787/ZK222584 (PTK/ZK) and examined the antitumor effects and the mechanism of action.

Methods

We studied two HCC cell lines, PLC/PRF/5 and HuH7, and a human umbilical vein endothelial cell line, HUVEC. We studied the effects of IFN/5-FU with or without PTK/ZK in growth inhibition assays, immunohistochemistry, Western blot analysis, and immunocytochemistry.

Results

In a HuH7 xenograft model, the combination of PTK/ZK and IFN/5-FU significantly inhibited proliferation, induced apoptosis, decreased microvessel density, reduced the number of tumor cells that expressed VEGF receptor 2 (VEGFR-2), and repressed the phosphorylation of Akt in vivo. In HCC cells and HUVECs in vitro, IFN/5-FU plus PTK/ZK repressed the expression of VEGFR-2 and repressed the phosphorylation of VEGFR, Akt, Erk, and p38MAPK.

Conclusions

VEGF signaling inhibition enhanced the antitumor effects of IFN/5-FU therapy on HCC cells and endothelial cells via Erk, Akt, and p38MAPK pathways.

     

Combined effect of TNF and anticancer chemotherapeutic agents on murine bladder tumor (MBT-2)]

The antitumor activity of combination therapy of recombinant human tumor necrosis factor alpha (rHu-TNF alpha) and chemotherapeutic agents against murine bladder tumor (MBT-2) was studied. Tumors were intradermally transplanted into the hind leg of C3H-HeN mice and allowed to grow until they reached a diameter of 8 to 10 mm 10 days after transplantation. TNF (3,000 units) was given intraperitoneally from day 10 to day 19, and the chemotherapeutic agents, 5-FU (60 mg/kg), CPM (100 mg/kg), CDDP (10 mg/kg) and ADM (5 mg/kg), were applied once intraperitoneally on day 10. The antitumor effects were evaluated based on tumor volume on day 20. 5-FU, CPM and ADM enhanced the antitumor effect when combined with TNF, but CDDP did not. These findings suggest that combination therapy of TNF and certain antitumor chemotherapeutic agents is effective cancer treatment.     

Tyrosine Kinase Inhibitor PTK/ZK Enhances the Antitumor Effects of Interferon-α/5-Fluorouracil Therapy for Hepatocellular Carcinoma Cells

Purpose

There is no standardized treatment for hepatocellular carcinoma (HCC) with portal vein tumor thrombus. We previously reported the efficacy of interferon-alpha and 5-fluorouracil combination (IFN/5-FU) therapy for these patients and the potential mechanism via the regulation of vascular endothelial growth factor (VEGF). In this study, we showed the VEGF-related effects of IFN/5-FU therapy using VEGF-receptor (VEGFR) selective inhibitor, PTK787/ZK222584 (PTK/ZK), in HCC cells.

Methods

Using two VEGF secreting and VEGFR expressing human HCC cell lines, PLC/PRF/5 and HuH7, we performed growth inhibitory assays in vitro and in vivo, apoptosis assay, cell cycle analysis, and Western blot analysis for the mechanism, with or without PTK/ZK in IFN/5-FU therapy.

Results

The combination of PTK/ZK and IFN/5-FU significantly inhibited cell growth in vitro and tended to reduce tumor growth in vivo in a HuH7 xenograft model in nude mice—in both cases without affecting VEGF secretion. PTK/ZK enhanced the IFN/5-FU induced apoptosis, based on increased proteins levels of Bax and reduced Bcl-xL and Bcl-2. Cell cycle analysis showed different results between the HCC cell lines following the combination therapy, possibly due to differences in p21 protein.

Conclusions

VEGF signaling inhibition would support an antitumor effect of IFN/5-FU therapy against HCC cell lines via induction of apoptosis and cell cycle delay.     

Antiproliferative activity of recombinant interferons alpha and beta for human renal carcinoma cells: Supra-additive activity with elevated temperature or vinblastine

Summary We are investigating IFN activity for human renal cell carcinoma (RCC) in conjunction with other forms of therapy in vitro. Our investigations employed IFN alpha and beta generated by recombinant DNA technology. We employed IFN species in conjunction with vinblastine or elevated temperature of incubation for RCC cells. Recombinant IFNs alpha and beta were provided by Triton/Cetus IFN program. RCC cells grown at 37°C with 1,000 IU/ml IFN alpha for seven days produced significant inhibition in growth kinetics (p<0.01). Incubation at 39.5 °C significantly augmented inhibition producing cytotoxicity without altering growth kinetics in controls (p<0.01). Treatment of cells with IFN beta (5 ng/ml) 24 hours prior to treatment with vinblastine (0.25 g/ml×1 h) resulted in supra-additive inhibition of growth kinetics as determined by isobole analysis (p<0.001). Concomitant treatment with IFN and vinblastine or IFN treatment 24 hours after vinblastine treatment augmented inhibition to a lesser extent. Our results suggest supra-additive biological activity of recombinant IFN at increased temperature, or with vinblastine.     

Synergy of interferon-alpha and 5-fluorouracil in human renal cell carcinoma requires p53 activity

ObjectivesImmunochemical therapy combining cytokines and chemotherapeutic agents is expected to be effective for treating advanced renal cell carcinoma (RCC). We investigated the mechanism underlying the synergism of interferon-α (IFN-α) and 5-fluorouracil (5-FU) and the effect of p53 status on the synergy of the combined therapy in RCC cell lines.MethodsThe synergy of IFN-α and 5-FU was analyzed by isobolographic analysis in five RCC cell lines. The effect of combined treatment on apoptosis induction was measured by flow cytometric analysis, Hoechst staining, and caspase activity assay; PCNA expression was investigated by Western blotting to examine the effect of combined treatment on the antiproliferative effect.ResultsWe demonstrated synergy of IFN-α and 5-FU in five RCC cell lines with wild-type p53. IFN-α suppressed the proliferation of RCC cells via G1 or G2/M cell cycle arrest without inducing apoptosis, whereas 5-FU induced apoptosis in a dosage-dependent manner. IFN-α enhanced the apoptosis of RCC cells induced by 5-FU, whereas 5-FU did not increase the antiproliferative effect of IFN-α. However, the synergistic inhibition by IFN-α and 5-FU was abolished when the cell lines were transfected with p53 dominant-negative vector.ConclusionsThe synergy of IFN-α and 5-FU requires p53 activity, suggesting that p53 status may serve as a predictive factor for response to the combination therapy. Because metastatic RCC frequently has p53 mutations, therapy restoring p53 may markedly improve the response rate of immunochemical therapy combining IFN-α and 5-FU.     

A randomized phase II trial comparing two different sequence combinations of autologous vaccine and human recombinant interferon gamma and human recombinant interferon alpha2B therapy in patients with metastatic renal cell carcinoma: clinical outcome and analysis of immunological parameters

PURPOSE: The clinical observation of spontaneous regression in patients with renal cell carcinoma (RCC) and the response to various immunotherapeutic therapies strongly suggest a role for the host immune system in this disease. Prior studies showed that sequential administration of interferon (IFN) gamma and IFN alpha to RCC patients was safe. Clinical responses as well as immune changes in the peripheral blood mononuclear cell compartment were observed. Autologous tumor cell vaccines (AV) have also demonstrated activity in renal cell carcinoma. We hypothesize that the addition of AV to sequential IFN gamma and a therapy might improve the tumor-specific immune response by providing an appropriate source of antigen in the appropriate cytokine environment. To our knowledge, this is the first trial using AV combined with IFN alpha and IFN gamma. The purpose of this study was to evaluate the feasibility of manufacturing and administering (AV) from resected tumor samples, and administration of AV with combination IFN gamma and IFN alpha therapy. Finally, the impact on immunological parameters of these treatment options was assessed. MATERIALS AND METHODS: Patients with metastatic RCC were randomly assigned to receive AV plus bCG along with a sequential administration of IFN gamma and a either together or after initiation of vaccine. Toxicity and clinical responses were evaluated. Modulations of the immune system were investigated by analyzing phenotype, cytokine mRNA expression, T cell proliferation and cytotoxicity in the peripheral blood mononuclear cell compartment. RESULTS: Fourteen patients with metastatic renal cell carcinoma were enrolled in this study; 9 were available for response evaluation. In a 70 day period, 3 (33%) showed mixed responses, 5 (56%) stable disease and 1 (11%) progression of disease. Toxicities were consistent with previous clinical reports. In the flow-cytometry phenotype analysis, stimulation of distinct subsets of circulating T-lymphocytes and a decrease of CD8+ T cell subsets was demonstrated. T-cell proliferation to allogeneic tumor cell stimulation improved following treatment. IL-4 and IL-5 mRNA levels were reduced in all patients after treatment. Patients who responded to treatment did not produce any IL-4 mRNA at all, before or after treatment. CONCLUSIONS: AV with IFNgamma and IFNalpha therapy might induce a MHC class-mediated cytotoxic T lymphocyte (CTL) response. We suggest that adequate therapy might direct T cell response toward a Th1 type response. We hypothesize a state of improved immune readiness in patients who might eventually respond to immunotherapy.     

Effects of experimental chemoendocrine therapy with a combination of a pure antiestrogen and 5-fluorouracil on human breast cancer cells implanted in nude mice

The antitumor effects of an experimental chemoendocrine therapy combining a new pure antiestrogen ICI 182780 and 5-fluorouracil (5-FU) were studied on MCF-7 human breast cancer cells implanted in nude mice. ICI 182780 had a dose-dependent antitumor activity, which was potentiated by the concomitant use of 5-FU. When compared with the control group, the estrogen receptor (ER) level in the ICI 182780 group was lower and that in the combination group was markedly lower. Cell cycle analysis by flow cytometry (FCM) resulted in a lower percentage of S-phase cells (%S) in the treated mice. No significant difference was observed in the 5-FU concentrations in tumor cells, while the 5-FU content in RNA was significantly higher in the combination group. The changes in free thymidylate synthetase (TS) concentration indicated TS synthesis after the administration of 5-FU to be more greatly suppressed in the combination group than in the 5-FU group. These results suggest that ICI 182780 and 5-FU exert their combination effect mainly on ER-positive cells, and that the suppression of TS synthesis in tumor cells and the potentiation of the 5-FU-induced metabolic dysfunction of RNA are thus involved in the mode of action of this combination therapy. A summary of this paper was presented at the Fourth General Conference of the Japan Breast Cancer Society and the 34th General Meeting of the Japan Society for Cancer Therapy.     

Treatment of Advanced Renal Cell Carcinoma with a Combination of Human Lymphoblastoid Interferon–Alpha and Cimetidine

Human lymphoblastoid interferon (IFN)–alpha was administered intramuscularly at doses of 5 megaunits/day 5 to 7 days a week to 32 advanced renal cell carcinoma patients. To augment the antitumor effect of IFN, cimetidine was also administered orally in doses oi 800 mg/day. This combination therapy resulted in a complete response (CR) in 6 patients (19%), a partial response (PR) in 7 (22%), a stable disease (SD) in 11 (34%), and a progressive disease (PD) in 8 (25%). The response rate (CR+PR) was 41%. The pulmonary metastases were more receptive to IFN therapy than those at other sites. The median times to response were 2 months for PR, and 4.5 months for CR. The survival of the responder patients was significantly longer than the nonresponder patients. These results suggest that IFN–alpha and cimetidine combination therapy may be of use in the management of advanced renal cell carcinoma.     

Effects of interferon beta ser and transforming growth factor beta on prostatic cell lines

The effect of interferon beta ser (IFN beta ser) on the growth of three prostatic cancer cell lines DU-145, PC-3 and LNCaP was studied. IFN beta ser inhibited growth of anchorage dependent semiconfluent monolayers and anchorage dependent colony formation of both DU-145 and PC-3 in a dose dependent manner but had no effect on LNCaP. Transforming growth factor beta (TGF beta 1) inhibited proliferation of DU-145 and PC-3 cells in 1% but not 8% fetal calf serum. The combination of TGF beta 1 and IFN beta ser was additive in its effects on growth. Neither epidermal growth factor (EGF) nor transforming growth factor alpha (TGF alpha) reduced the antiproliferative effect of IFN beta ser on these cells. These antiproliferative effects were reproduced in studies on primary epithelial cell cultures derived from prostate specimens with various pathologies. The potential use of IFN beta ser in combination with hormonal therapy to delay the development of hormone refractory tumors is discussed.     

A new interferon-alpha assay system including indirect antitumor effect. Basic and clinical study of renal cell carcinoma]

In this report, the clinical value of a new interferon (INF) assay and measuring serum tumor necrosis factor (TNF) titer in renal cell carcinoma (RCC) patients is described. In order to find out ineffective cases, we established a new in vitro IFN assay system which was modified from human tumor clonogenic assay (HTCA) using an underlayer including monocytes (5 x 10(4)/dish) and lymphocytes (5 x 10(5)/dish) as the feeder cells obtained from human peripheral venous blood. This assay can evaluate both direct and indirect (immune mediated) antitumor effects. Various kinds of cytokines (TNF alpha, IL-1 alpha, -1 beta) were measured simultaneously in the cultured supernatants in vitro as well as the serum value in vivo by sandwich immunoenzymometric assay to compare the relationship between antitumor effect and clinical course. In the basic study, cultured ACHN cell line was used as the target cells. The inhibition of colony growth was observed in a dose relative manner. Continuous IFN-alpha exposure of 50 and 500 IU/ml in the presence of feeder cells showed a significant reduction of colony growth in comparison with cultured plates containing the drug only. Among the cytokines in the supernatants after incubation for 24 hours with IFN-alpha (500 IU/ml) including feeder cells, only TNF alpha showed significant elevation. In the clinical study, 31 RCC patients were tried for sensitivity testing using modified HTCA system. The sufficient colony growth was observed in 19 cases (61%). In 25 cases serum cytokines were compared with preoperative and postoperative values; twenty cases received post-operative IFN-alpha administrations, and 5 cases did not. Seven of the 20 cases with IFN-alpha therapy had some evaluable lesions. 1) The rates of colony survivals were correlated with TNF alpha titers in the supernatants (r = -0.90, p less than 0.01). 2) The serum levels of TNF alpha rose in 15 of the 20 cases (75%) after IFN-alpha therapy. The elevated value was significantly higher than the value of pretreatment period (p less than 0.05, paired t-test). 3) There was a significant correlation between the TNF alpha titers in the supernatants (in vitro) and in the sera (in vivo) treated with IFN-alpha. 4) All of 3 cases with low serum TNF alpha titers during IFN therapy showed progressive disease. But in 4 cases with high serum TNF alpha titers metastatic lesions did not change in more than one year.(ABSTRACT TRUNCATED AT 400 WORDS)     

Bedeutung der Immunochemotherapie für das Überleben von Patienten mit metastasiertem Nierenzellkarzinom

The prognosis for patients with metastatic renal cell carcinoma (RCC) remains unsatisfactory to date. Combined immunochemotherapy (ICT) strives for a synergistic effect avoiding a substantial increase of therapy-related adverse events. The combination therapy regimes consisting of either interferon-alpha-2a/vinblastine (IFN-alpha2a/VBL) or interferon-alpha-2a/interleukin-2/5-fluorouracil (IFN-alpha2a/IL-2/5-FU) demonstrated objective remission rates, surpassing the results obtained with the administration of single immunotherapeutic agents. Despite the data from a recently published study, the role of these two therapy combinations did not seem clearly defined. Therefore, we compared the impact of IFN-alpha2a/VBL and IFN-alpha2a/IL-2/5-FU on remission and survival as well as the safety profile in a retrospective study in patients with metastatic RCC.In a retrospective single-center study, 105 patients with metastatic RCC having received treatment between 1992 and 2002 with either s.c. IFN-alpha2a/ i.v. VBL ( n=70, group 1) or s.c. IFN-alpha2a/ s.c. IL-2/ i.v. 5-FU ( n=35, group 2) were evaluated. At a median follow-up of 17 months, remission and survival rates as well as the toxicity profiles of the respective groups were documented and compared.The median age throughout the entire patient population was 61 years. Patients in the IFN-alpha2a/VBL group reached a median overall survival of 20 months compared to 17 months for the patients in the IFN-alpha2a/IL-2/5-FU population ( p=0.850). The objective response rate in the first patient group reached 25.7%, whereas the tumor remission rate of group 2 amounted to 22.9% ( p=0.680). Patients showing an objective response reached a significantly higher survival rate than patients without response reaction (median survival was 36 vs 10 months, p=0.0001). The incidence of each therapy-induced adverse event was higher throughout the second treatment group. These differences were significant with respect to flu-like symptoms (85.7 vs 57.1%, p=0.003), grade 3/4 elevations of liver enzymes (14.3 vs 1.4%, p=0.007), nausea/vomiting (74.3 vs 50%, p=0.017), the severity of erythemas (74.3 vs 10%, p<0.001), and patients with lung edema (17.1 vs 2.9%, p=0.009). Eight patients discontinued the ICT, two of whom died of a myocardial infarction.Despite an overall limited prognosis, patients showing a tumor remission seem to benefit from ICT in terms of overall survival. While both treatment options offer comparable remission and survival rates, the IFN-alpha2a/VBL regimen induces fewer adverse events than the treatment with IFN-alpha2a/IL-2/5-FU.     

Comparative antitumor activity of 5-fluorouracil and 5'-deoxy-5-fluorouridine in combination with interferon-alpha 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.     

Sunitinib malate is active against human urothelial carcinoma and enhances the activity of cisplatin in a preclinical model

PurposeSunitinib malate (Pfizer, Inc.) is a multitargeted kinase inhibitor that inhibits vascular endothelial growth factor (VEGF) receptor (R)-1, 2 and 3, platelet-derived growth factor receptors (PDGFR)-α and β, Flt3, RET, and Kit. Angiogenesis and VEGF expression correlate with poor outcomes in human urothelial carcinoma. We designed a preclinical study to examine the efficacy of sunitinib alone and in combination with cisplatin against human urothelial carcinoma.DesignThe in vitro activities of sunitinib and cisplatin alone and in combination were determined against human urothelial carcinoma cell lines, TCC-SUP and 5637. Antitumor activities were also determined in vivo against murine subcutaneous 5637 xenografts. Immunohistochemistry (IHC) was performed to detect VEGFR2 and Kit, and modulation of proliferation, apoptosis, and angiogenesis.ResultsBoth cell lines expressed VEGFR2, but did not express Kit. Sunitinib displayed activity against both cell lines in vitro at low micromolar concentrations, which are not attainable in vivo, and was synergistic with cisplatin. Activity was observed for sunitinib at 20 and 40 mg/kg orally once daily for 4 weeks, which attains low nanomolar concentrations in vivo against murine 5637 xenografts. Sunitinib 20 mg/kg/d in combination with cisplatin 4 mg/kg/wk intraperitoneally induced tumor regression compared to no therapy (P < 0.0001) or cisplatin alone (P = 0.06). Cisplatin, sunitinib, and combination treated tumors displayed significantly reduced ki-67 expression compared with control untreated tumors, and the difference was also statistically significant for the combination compared with cisplatin. Cleaved caspase-3 expression was significantly higher for sunitinib single agent and combination therapy compared with untreated controls, and for combination therapy compared with cisplatin alone. CD31 expression was diminished for both single agents and combination therapy compared with untreated tumors.ConclusionsSunitinib is preclinically active against urothelial carcinoma, and enhances the activity of cisplatin probably by targeting the stroma.     

Treatment of bone metastases and local recurrence from renal cell carcinoma with immunochemotherapy and radiation

Summary Immunotherapies using interferons and/or interleukins are currently the treatment of choice for metastatic renal cell carcinoma (RCC). Bone metastases and non-resectable local recurrence are negative predictors for successful immunotherapy and signs of poor prognosis. The present study was designed to evaluate the effectiveness of combined immunochemotherapy (ICT) and radiation therapy (RT) for bone metastases or local recurrence from RCC in a prospective fashion. From September 1997 to September 1999, 20 patients with progressive RCC were treated with a combination of RT and ICT [s.c. interleukin-2a (IL-2), s.c. interferon alpha (IFN-) and i.v. 5-fluorouracil]. RT started in week 2 of ICT. The radiation field was limited to the symptomatic bone metastases (15 patients) or the local recurrence (five patients). The total dosages of the RT ranged between 45 and 50 Gy, administered in fractions of from 1.8 to 2 Gy daily. In case of objective response or stable disease, the patients received up to two further ICT courses. All patients had good pain relief. Three out of 20 achieved complete remission, three had a partial remission, nine were stable and five patients had progressive disease under the combined treatment. Median survival was 21 months, mean survival 24 months (range: 5–59 months). The side effects of the combined treatment are in the same range as with ICT alone (World Health Organisation grade 2 and 3). Of 20 patients, 19 had their pain medication reduced after treatment. The combination of ICT and RT is feasible. There is remarkable pain relief. Our data suggest that the combination of immunochemotherapy and radiation therapy may induce a synergistic antitumor effect for the treatment of bone metastases or local recurrence from RCC compared to data from the literature for ICT or RT alone.