Antiproliferative effects of interferons -alpha and -beta in combination with 5-fluorouracil, cisplatin, and cis- and trans-retinoic acid in three human lung carcinoma cell lines

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.

Lack of interferon beta-induced radiosensitization in four out of five human glioblastoma cell lines

PURPOSE

To investigate the potential of interferon beta to enhance the cytotoxic activity of ionizing irradiation against glioma cells, and to elucidate the possible mechanisms responsible for conflicting clinical results.

METHODS AND MATERIALS

Five glioblastoma cell lines (U87MG, U118MG, U373MG, MO59K, MO59J) with different radiosensitivity and genetic background were used. Experiments were performed in exponentially growing cultures, and cell survival was measured by a colony-forming assay. Cells were incubated with natural interferon beta (n-IFN-beta; 30-3000 IU/mL) for 24 h followed by single dose irradiation with 1 to 6 Gy of gamma-rays.

RESULTS

Significant differences in n-IFN-beta sensitivity were found. The cell lines also differed in their radiation sensitivity, and there was no correlation between the n-IFN-beta and the radiation sensitivity. In three of five cell lines, the interaction of n-IFN-beta and irradiation was infra-additive; in one cell line, it was additive. For MO59J cells only, which are NHEJ-deficient, supra-additivity was observed.

CONCLUSION

Our results confirm the remarkable heterogeneity that is characteristic of malignant glioma. The combined effect of n-IFN-beta and radiation was mostly infra-additive or additive; synergistic interaction might occur in tumor cells that already have acquired repair deficiencies because of their genetic instability, as shown for the MO59J cell line.

The influence of very low doses of Cisplatin on tumor cell proliferation in vitro and on some hematological and enzymatic parameters of healthy rats

Healthy rats had been treated for 2 or 6 weeks with 1.0 mL of 10(-8) and 10(-16) mg/mL of cisplatin. After 2 weeks of treatment, a significant increase in leukocyte and erythrocyte count and also in hematocrit was observed. Among leukocytes the number of neutrophils and eosinophils significantly increased. Biochemical analyses indicated a decrease in the glycogen content in the liver and kidneys after 2 weeks of treatment with low doses of cisplatin but at the end of the experiment (8th week of experiment) the stores of glycogen increased significantly. Biochemical analyses concerning the activity of some enzymes in the liver revealed a significant increase of peroxidase and acid phosphatase as well as catalase activities after 2 weeks of treatment. However, catalase was induced by a very low concentration of cisplatin, 10(-16) mg/mL. After the cessation of cisplatin treatment the activity of enzymes returned to normal values.Human lung carcinoma cell line A(549) (ECACC No 86012804) was also studied after treatment with the same doses of cisplatin and inhibition of its growth was observed. The results of these experiments strongly indicated that low doses of cisplatin could be stimulating for healthy cells but cytostatic for tumor cells.Possible mechanisms involved in the biological activity of very low cisplatin concentrations are discussed.

Combination of chemotherapy and recombinant interferon-alpha in advanced non-small cell lung cancer

Some studies have shown that the combination of chemotherapy and interferon in non-small cell lung cancer (NSCLC) and other solid tumors is feasible and possesses antitumor activity. Our study was aimed at verifying whether the addition of recombinant human interferon alpha (rh-IFN alpha) to combined chemotherapy would be able to increase the response rate and survival of patients with NSCLC. Thirty-eight patients with previously untreated advanced NSCLC were evaluated in this study. Median age of patients was 57 years; performance status according to ECOG 0 and 1, 37 pts (97%); stage IIIB, 27 pts (71%); stage IV, 11 pts (29%). Histology was squamous cell carcinoma in 53%, adenocarcinoma 44% and large cell carcinoma 3%. Our schedule consisted of 80 mg/m2 cisplatin I.V., 100 mg/m2 etoposide I.V., 10 million U rh-IFN alpha IM and 10 million U rh-IFN alpha I.V. on first day of treatment, every 3 weeks. None of the patients had complete response. Partial response rate was 34%. Median response duration was 7 months (range 3-19 months), median survival time was 11 months (range 4-41 months). Twenty-nine percent of patients had grade 3 nausea and vomiting, 24% had grade 2 leucopenia, 5% had grade 2 cardiotoxicity, 2.6% had flu-like syndrome. According to these results, in advanced NSCLC, the addition of rh-IFN alpha did not increase the cisplatin-etoposide combined chemotherapy induced response rate and survival time.

All-trans-retinoic acid and pseudotumor cerebri

Pseudotumor cerebri or idiopathic intracranial hypertension is a neurological syndrome characterized by signs and symptoms of intracranial hypertension without clinical and radiological evidence of infective or space occupying lesions. Iatrogenic factors are frequent; in particular, cases of Pseudotumor cerebri associated with all-trans-retinoic acid treatment in acute promyelocytic leukemia (APL) have been frequently described in pediatric patients. We review the literature and give diagnostic and therapeutic guidelines.

In vitro growth inhibition activities of recombinant feline interferon on all lines derived from canine tumours

To evaluate the anti-tumour effect of recombinant feline interferon (rFeIFN) against canine neoplastic cells, the antiproliferation and anti-colony-forming activities of rFeIFN were investigated in vitro, using four cell lines derived from canine tumours; oral acanthomatous epulis (MCA-B1), mammary benign mixed tumour (MCM-B2), squamous cell carcinoma (CSCC), and malignant melanoma (CMC-1). The rFeIFN had a dose-dependent inhibitory effect on the cell growth and colony formation of all the cell lines, although the degree of inhibition was lower than that in the feline cell lines used as a positive control, and the sensitivity of the cells to rFeIFN differed.

New targets for pyrimidine antimetabolites in the treatment of solid tumours. 1: Thymidylate synthase

Thymidylate synthase forms the target for anticancer therapy with fluoropyrimidines. Anticancer activity can be increased by the use of different modulators of fluoropyrimidine metabolism, which lead to an enhanced inhibition of thymidylate synthase. In vitro and in vivo studies with fluoropyrimidines and two of these modulators, folinic acid (leucovorin) and interferon, are summarized. The promise of these preclinical results is reflected by the response data of several clinical trials. The biochemical effects of these modulators are described and illustrated by the fluoropyrimidine-mediated inhibition of thymidylate synthase in tumour samples, which is clearly enhanced by folinic acid. The regulation of thymidylate synthase synthesis may also be crucial for total blockade of thymidylate synthase activity. This regulation may be influenced by interferon-gamma. Although the addition of modulators increases the activity of fluoropyrimidines at the level of thymidylate synthase, most solid tumours, especially colorectal carcinomas, are resistant to these combinations. For this reason, new, more potent inhibitors of thymidylate synthase have been developed, the antifolates. Preclinical data show that some of these compounds have good antitumour activity, but they still have to prove their value in the clinic. These two approaches, the use of modulators and new compounds, have shown activity preclinically and the extension of these findings to clinical studies stresses the importance of thymidylate synthase as a target in fluoropyrimidine therapy of solid tumours.