Interferon treatment of murine Meth-A sarcoma cells: effects on the malignant phenotype and expression of tumor-specific and H-2 antigens

Cisplatin, mitomycin, and interferon-alpha2a combination chemoimmunotherapy in the treatment of diffuse malignant pleural mesothelioma

STUDY OBJECTIVE

To investigate the therapeutic activity and toxicity of combination chemoimmunotherapy with cisplatin, mitomycin, and interferon (IFN)-alpha2a, by comparing the responses in a group of patients with diffuse malignant pleural mesothelioma (DMPM) to the responses in a control group of DMPM patients given supportive care alone.

DESIGN

Patients with histopathologically confirmed DMPM were evaluated for treatment with chemoimmunotherapy.

SETTING

After the initial evaluation, all patients received either chemoimmunotherapy or supportive care from the Osmangazi University Medical Faculty, Department of Chest Diseases.

PATIENTS

Forty-three patients with DMPM received chemoimmunotherapy until the end of the survey; 19 patients were given supportive therapy alone after refusing chemoimmunotherapy.

INTERVENTIONS

Drugs were administered according to the following schedule: IV cisplatin, 30 mg/m2 qd on days 1 and 2; IV mitomycin, 8 mg/m2 on day 1; and subcutaneous IFN-alpha2a, 4.5 million IU twice weekly. The courses were repeated every 4 weeks.

RESULTS

Overall, 232 chemoimmunotherapy cycles were administered. A total of 10 objective responses (ORs) in 43 patients (23%) were assessed, including 2 complete responses (5%), 4 partial responses, and 4 regressions. Seventeen patients had stable disease, and 16 patients had progression. The median survival time was 11.5 months for the 43 patients who received chemoimmunotherapy and 7.0 months for the 19 patients who received supportive therapy alone. The difference in survival times between the chemoimmunotherapy and supportive therapy groups was not significant. However, the median survival time for the patients who had OR was 21.3 months, which is significantly longer than that of the patients who received supportive care alone and that of patients with progressive disease (6 months). The toxicities associated with the treatment schedule of this study were, for the most part, tolerable.

CONCLUSIONS

The drug combination used in this study is moderately effective and well tolerated in patients with DMPM, especially in those who responded to the treatment.

Positive interactions between human interferon and cepharanthin against human cancer cells in vitro and in vivo

A human tumor microcytotoxicity-viable cell-staining assay was used to test the antiproliferative effect of recombinant human interferon-beta or -gamma alone and in combination with bisbenzylisoquinoline alkaloid cepharanthin against four human tumor cell lines in vitro and in nude mice. Results obtained in the in vitro study indicate that combinations of interferon-beta/-gamma with cepharanthin show synergistic and, occasionally, additive antiproliferative effects in a dose-dependent manner on tumor viable cell-staining assay. Interferon-gamma combined with cepharanthin suppressed the growth of all four human tumor cell lines (RPMI 4788, PC 10, HeLa, ZR-75-1), and this enhanced antiproliferative effect was not dependent on the interferon species involved, including interferon-beta and -gamma. In an experimental model of pulmonary metastasis, in which human colon tumor cells were inoculated i.v. into nude mice, interferon-gamma alone exerted significant inhibitory activity against pulmonary metastasis in a dose-dependent manner, and cepharanthin alone also significantly inhibited metastasis. Furthermore, a combination of interferon-gamma with cepharanthin resulted in a considerable suppression of pulmonary metastasis. These studies indicate that due to their therapeutic potential, combinations of recombinant human interferon-beta or -gamma with cepharanthin might be a promising therapy for pulmonary metastasis of human cancers.

Antitumor activity of T cells in lymphoid organs induced by interferon in tumor-bearing mice

Administration of human hybrid interferon-alpha A/D (IFN) for 5 consecutive days induced antitumor activity in spleen of Meth A fibrosarcoma-bearing mice 9-10 days after cessation of IFN administration. Antitumor activity assayed by the in vivo neutralization test was found in the spleen of responding mice but not in that of progressive mice. This activity was T-cell-dependent and tumor-selective. However, tumor-neutralizing activity was not found in spleen recovered as early as 3 days after cessation of IFN administration when many tumor cells are still surviving in tumor nodules and being attacked by the host. Instead, T-cell-dependent and tumor-selective tumor-neutralizing activity was found in the lymph node of tumor-bearing mice at this early stage. Furthermore, the tumor-neutralizing activity was already detected in the lymph nodes during the course of IFN administration, although there was no difference in the cell composition of the lymph nodes of IFN- and placebo-administered mice. Since IFN-alpha is apparently not a direct modifier of T cells, these results indicate that IFN probably did not directly increase the number of antitumor T cells but instead modified the host-tumor interaction in such a way that, as an early event, the enhanced T-cell response to tumor cells occurred, resulting in an increase in the antitumor T-cell population in lymph nodes. We supposed that, as the tumor regressed, these antitumor T cells would eventually leave the lymph node and migrate to the spleen.