Studies with interferon-α in human tumors

Clinical trials with IFN-α, produced from buffy coats of leukocytes, have been going on at Radiumhemmet, Karolinska Hospital since 1969. In some of the benign and malignant tumor diseases studied, IFN has been shown to induce regressions. In the case of the benign tumor juvenile laryngeal papillomatosis, IFN has been shown to be superior to other treatment modalities. So far IFN has not been shown to be superior to conventional treatment in any of the malignant tumors studied.     

Characteristics of in vitro antiproliferation activity of human interferon-β

Summary We compared the in vitro antiproliferative activity of highly purified interferon (IFN)- (>10⁷ U protein/mg in antiviral activity) with that of IFNs- and lymphoblastoid, using human cells of malignant and non-malignant origin. IFN- was the least active of three IFNs in suppressing Daudi cell proliferation. Three hematological cells other than Daudi cells cultivated in suspension were insensitive to each of three IFNs. IFN- was more active than IFNs- and lymphoblastoid in suppressing all eight epithelioid cells tested and, particularly with respect to five epithelioid cells sensitive to IFN, IFN- was seven to 49 times as active as IFN-. These results indicate that suppression of cell proliferation by IFN depends not only on the target cell species but also on the IFN species, and emphasize the need for careful selection of the most appropriate IFN species in therapy.We found that the antiproliferative characteristics of the present IFN- preparation were consistent with those reported previously, supporting the idea that IFN- molecules in the present preparation were responsible for suppressing cell proliferation. The antiproliferation activity of our preparation was species-specific but not selective for cells of malignant origin; it was absorbable by IFN-sensitive but not by IFN-insensitive cells; and it was achieved by a cytostatic effect.     

Inhibition of the growth of cultured human meningioma cells by recombinant interferon-α

In this paper the results of investigations on the effect of interferon-α (IFN-α) on the growth of meningioma cells in culture is reported. A consecutive series of six meningiomas and one meningioma/neurofibroma derived from a patient with neurofibromatosis type 2 was investigated and it was found that the growth of all seven tumours in response to mitotic stimuli (fetal bovine serum or epidermal growth factor) is strongly inhibited by IFN-α. Maximal response varied between 100% and 70% inhibition of the incorporation of tritiated thymidine. In some cases an inhibitory response was obtained already at very low doses (≤10 U of IFN-α per ml). These results indicate that further clinical investigation of the application of IFN-α to the treatment of meningioma is warranted.     

Characterization of interferon-γ-treated melanoma tumor cells for use in dendritic cell-based immunotherapy

Efficient delivery of tumor-associated antigens to professional antigen-presenting cells is important for inducing a response in patients receiving cancer immunotherapy. Interferon-gamma (IFN-γ) is used by the immune system to combat viral and fungal infections by restricting cell proliferation and, in some cases, inducing apoptosis. Using IFN-γ to activate target tumor cells prior to antigen loading of dendritic cells (DCs) may enhance the beneficial qualities of whole-cell tumor vaccines. The incubation of melanoma cell cultures with IFN-γ resulted in an increase in the expression of major histocompatibility complex molecules and ICAM-1 but generally decreased the expression of melanoma-associated tumor antigens. Additionally, important immune-stimulating molecules (heat-shock proteins, high-mobility group box-1 protein, and calreticulin) were also present but differentially regulated by IFN-γ. Loading of DCs with IFN-γ-treated tumor cells resulted in a small but significant increase in the expression of CD83-positive DCs, indicating the initiation of DC maturation (p=0.019). IFN-γ treatment of melanoma cell lines prior to antigen loading of DCs may aid in antigen processing and presentation.     

Early activation and interferon-γ production of tumor-infiltrating mature CD27 high natural killer cells

Natural killer (NK) cells are known to be critically involved in the control of tumors through their direct cytotoxic function, but have also been proposed as an initial source of interferon (IFN)-γ that primes subsequent adaptive tumor-specific immune responses. Although mounting evidence supports the importance of NK cells in antitumor immune responses, the immunological characteristics of NK cells infiltrating the tumor microenvironment and the mechanisms that regulate this process remain unclear. In the present study, we found that NK cells infiltrate early developing MCA205 tumors, and further showed that mature CD27(high) NK cells were the predominant subpopulation of NK cells accumulating in the tumor microenvironment. The tumor-infiltrating NK cells displayed an activated cell surface phenotype and provided an early source of IFN-γ. Importantly, we also found that host IFN-γ was critical for NK cell infiltration into the local tumor site and that the tumor-infiltrating NK cells mainly suppressed tumor growth via the IFN-γ pathway. This work implicates the importance of IFN-γ as a positive regulatory factor for NK cell recruitment into the tumor microenvironment and an effective antitumor immune effector response.     

Adjuvant interferon-α for the treatment of high-risk melanoma: An individual patient data meta-analysis

BackgroundMany randomised trials assessing interferon-α (IFN-α) as adjuvant therapy for high-risk malignant melanoma have been undertaken. To better assess the role of IFN-α, an individual patient data (IPD) meta-analysis of these trials was undertaken.MethodsIPD was sought from all randomised trials of adjuvant IFN-α versus no IFN-α for high-risk melanoma. Primary outcomes were event-free survival (EFS) and overall survival (OS). Standard methods for quantitative IPD meta-analysis were used. Subgroup analyses by dose, duration of treatment and various patient and disease-specific parameters were performed.FindingsFifteen trials were included in the analysis (eleven with IPD). EFS was significantly improved with IFN-α (hazard ratio [HR] = 0.86, CI 0.81–0.91; P < 0.00001), as was OS (HR = 0.90, CI 0.85–0.97; P = 0.003). The absolute differences in EFS at 5 and 10 years were 3.5% and 2.7%, and for OS were 3.0% and 2.8% respectively in favour of IFN-α. There was no evidence that the benefit of IFN-α differed depending on dose or duration of treatment, or by age, gender, site of primary tumour, disease stage, Breslow thickness, or presence of clinical nodes. Only for ulceration was there evidence of an interaction (test for heterogeneity: P = 0.04 for EFS; P = 0.002 for OS); only patients with ulcerated tumours appeared to obtain benefit from IFN-α.ConclusionThis meta-analysis provides clear evidence that adjuvant IFN-α significantly reduces the risk of relapse and improves survival and shows no benefit for higher doses compared to lower doses. The increased benefit in patients with ulcerated tumours, and lack of benefit in patients without ulceration, needs further investigation.     

Adenoviruses-mediated transduction of human oesophageal carcinoma cells with the interferon-λ genes produced anti-tumour effects

Background:

Interferon-λs (IFN-λs) are novel cytokines with multiple functions, like IFN-α and -β. We examined possible anti-tumour effects produced by adenoviruses bearing the IFN-λ1 or -λ2 gene (Ad/IFN-λ) with the type-35 fibre-knob structure.

Methods:

Proliferation of oesophageal carcinoma cells transduced with Ad/IFN-λ and mechanisms of the inhibited growth were investigated.

Results:

Transduction with Ad/IFN-λ upregulated the expression of the class I antigens of the major histocompatibility complexes and induced the growth suppression. Increased sub-G1 populations and the cleavage of caspase-3 and poly (ADP-ribose) polymerase were detected in IFN-λ-sensitive YES-2 and T.Tn cells. The cell death was accompanied by cytoplasmic cytochrome C and increased cleaved caspase-9 and Bax expression, suggesting mitochondria-mediated apoptosis. Adenovirus/IFN-λ-infected YES-2 cells subsequently reduced the tumourigenicity. Adenovirus/IFN-λ-infected fibroblasts, negative for the IFN-λ receptors, induced death of YES-2 or T.Tn cells that were co-cultured. Inoculation of YES-2 cells in nude mice, when mixed with the Ad/IFN-λ-infected fibroblasts, resulted in retardation of the tumour growth. The growth suppression was not linked with upregulated CD69 expression on natural killer cells or increased numbers of CD31-positive cells.

Conclusion:

Adenovirus/IFN-λ induced apoptosis, and fibroblast-mediated delivery of IFN-λs is a potential cancer treatment by inducing direct cell death of the target carcinoma.     

Potent systemic therapy of multiple myeloma utilizing oncolytic vesicular stomatitis virus coding for interferon-β

Multiple myeloma (MM) is an incurable malignancy of plasma secreting B cells disseminated in the bone marrow. Successful utilization of oncolytic virotherapy for myeloma treatment requires a systemically administered virus that selectively destroys disseminated myeloma cells in an immune-competent host. Vesicular stomatitis virus (VSV)-expressing interferon-β (IFNβ) is a promising new oncolytic agent that exploits tumor-associated defects in innate immune signaling pathways to destroy cancer cells specifically. We demonstrate here that a single, intravenous dose of VSV coding for IFNβ (VSV-IFNβ) specifically destroys subcutaneous and disseminated 5TGM1 myeloma in an immune-competent myeloma model. VSV-IFN treatment significantly prolonged survival in mice bearing orthotopic myeloma. Viral murine IFNβ expression further delayed myeloma progression and significantly enhanced survival compared with VSV-expressing human IFNβ. Evaluation of VSV-IFNβ oncolytic activity in human myeloma cell lines and primary patient samples confirmed myeloma-specific oncolytic activity, but revealed variable susceptibility to VSV-IFNβ oncolysis. The results indicate that VSV-IFNβ is a potent, safe oncolytic agent that can be systemically administered to target and destroy disseminated myeloma effectively in immune-competent mice. IFNβ expression improves cancer specificity and enhances VSV therapeutic efficacy against disseminated myeloma. These data show VSV-IFNβ to be a promising vector for further development as a potential therapy for the treatment of MM.     

Histone deacetylase inhibitor augments anti-tumor effect of gemcitabine and pegylated interferon-α on pancreatic cancer cells

Background  

Histone deacetylase (HDAC) is strongly associated with epigenetic regulation and carcinogenesis, and its inhibitor can induce the differentiation or apoptosis of cancer cells.     

No synergistic activity of epirubicin and interferon-α2b in the treatment of hepatocellular carcinoma

Single-agent activity for anthracyclines reflected by response rates of 10%–30% has been reported in patients with advanced hepatocellular carcinoma (HCC). Preclinical data indicate that -interferon could enhance the cytotoxic activity of the anthracycline Adriamycin or its analog epirubicin. In a phase I/II study, 31 patients with biopsy-proven inoperable HCC were treated with interferon-2b given s. c. at a dose of 3×10⁶ units/m² per day for 5 days per week plus weekly epirubicin given at 25 mg/m² as an i. v. bolus. The protocol called for 4 consecutive weeks of treatment followed by 1 week off treatment. In all, 15 patients had been previously treated; 6 patients had failed hormonal therapy (tamoxifen), 5 patients had failed prior anthracycline treatment, and 4 patients had received chemoembolization of the tumor and had subsequently progressed. A total of 30 patients were evaluable for response. In all, 1 patient (3%) achieved a partial response for 8+ months and 11 patients (35%) achieved stabilization of disease. Six patients had a fall in alpha-fetoprotein (AFP) values of >50% during therapy. The median survival for all patients was 9.5 months (range, 3–34+ months). The main side effects were hematological toxicity and fever, both of which were considered tolerable. As an indicator of the immunostimulatory effects of interferon, an elevation in serum markers of inflammation [C-reactive protein (CRP), ₂-microglobulin] was found in 15%–20% of patients. All patients had measurable Mx protein production during therapy, but these effects were not correlated to the clinical response. The clinical response rate achieved in this trial indicates that the combination of interferon and epirubicin, at least when used on the schedule reported herein, is not superior to treatment with either agent alone for patients with advanced HCC. However, single patients achieved a prolonged progression-free interval (8–10+ months) on this therapy, and it may therefore be an option for patients who have failed prior hormonal or single-agent anthracycline therapy.     

Sensitization of interferon-γ induced apoptosis in human osteosarcoma cells by extracellular S100A4

Background

S100A4 is a small Ca²⁺-binding protein of the S100 family with metastasis-promoting properties. Recently, secreted S100A4 protein has been shown to possess a number of functions, including induction of angiogenesis, stimulation of cell motility and neurite extension.

Methods

Cell cultures from two human osteosarcoma cell lines, OHS and its anti-S100A4 ribozyme transfected counterpart II-11b, was treated with IFN-γ and recombinant S100A4 in order to study the sensitizing effects of extracellular S100A4 on IFN-γ mediated apoptosis. Induction of apoptosis was demonstrated by DNA fragmentation, cleavage of poly (ADP-ribose) polymerase and Lamin B.

Results

In the present work, we found that the S100A4-expressing human osteosarcoma cell line OHS was more sensitive to IFN-γ-mediated apoptosis than the II-11b cells. S100A4 protein was detected in conditioned medium from OHS cells, but not from II-11b cells, and addition of recombinant S100A4 to the cell medium sensitized II-11b cells to apoptosis induced by IFN-γ. The S100A4/IFN-γ-mediated induction of apoptosis was shown to be independent of caspase activation, but dependent on the formation of reactive oxygen species. Furthermore, addition of extracellular S100A4 was demonstrated to activate nuclear factor-κB (NF-κB).

Conclusion

In conclusion, we have shown that S100A4 sensitizes osteosarcoma cells to IFN-γ-mediated induction of apoptosis. Additionally, extracellular S100A4 activates NF-κB, but whether these events are causally related remains unknown.

     

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.     

Induction of apoptosis in glioma cells and upregulation of Fas expression using the human interferon-β gene

We investigated whether IFN-β inhibits the growth of human malignant glioma and induces glioma cell apoptosis using the human IFN-β gene transfected into glioma cells. A eukaryonic expression vector (pSV2IFNβ) for IFN-β was transfected into the glioma cell line SHG44 using liposome transfection. Stable transfection and IFN-β expression were confirmed using an enzyme-linked immunosorbent assay (ELISA). Cell apoptosis was also assessed by Hoechst staining and electron microscopy. In vivo experiments were used to establish a SHG44 glioma model in nude mice. Liposomes containing the human IFN-β gene were injected into the SHG44 glioma of nude mice to observe glioma growth and calculate tumor size. Fas expression was evaluated using immunohistochemistry. The IFN-β gene was successfully transfected and expressed in the SHG44 glioma cells in vitro. A significant difference in the number of apoptotic cells was observed between transfected and non- transfected cells. Glioma growth in nude mice was inhibited in vivo, with significant induction of apoptosis. Fas expression was also elevated. The IFN-β gene induces apoptosis in glioma cells, possibly through upregulation of Fas. The IFN-β gene modulation in the Fas pathway and apoptosis in glioma cells may be important for the treatment of gliomas.     

MicroRNA-21 induces resistance to the anti-tumour effect of interferon-α/5-fluorouracil in hepatocellular carcinoma cells

Background:

We reported recently the clinical efficiency of interferon (IFN)-α/5-fluorouracil (5-FU) combination therapy in advanced hepatocellular carcinoma (HCC). However, prediction of the response to the combination therapy remains unsatisfactory. The aim of this study was to investigate the anti-tumour effects of microRNA (miR)-21 on the sensitivity of HCC cells to IFN-α/5-FU and whether miR-21 can be used as a predictor of the response to such therapy in HCC.

Methods:

Changes in the sensitivity of HCC cells (PLC/PRF/5 and HepG2) to IFN-α/5-FU were examined after transfection with pre-miR-21 or anti-miR-21. The correlation between miR-21 expression level, evaluated by qRT–PCR, and response to the therapy was also investigated in clinical HCC specimens.

Results:

Hepatocellular carcinoma cells transfected with pre-miR-21 were significantly resistant to IFN-α/5-FU. Annexin V assay showed that the percentage of apoptotic cells was significantly lower in cells transfected with pre-miR-21 than control cells. Transfection of anti-miR-21 rendered HCC cells sensitive to IFN-α/5-FU, and such sensitivity was weakened by transfection of siRNAs of target molecules, PETN and PDCD4. miR-21 expression in clinical HCC specimens was significantly associated with the clinical response to the IFN-α/5-FU combination therapy and survival rate.

Conclusions:

The miR-21 in HCC cell lines and clinical HCC samples is a significant modulator of the anti-tumour effect of IFN-α and 5-FU. This suggests that miR-21 is a potentially suitable marker for the prediction of the clinical response to the IFN-α/5-FU combination therapy.     

A novel approach in the treatment of neuroendocrine gastrointestinal tumors: Additive antiproliferative effects of interferon-γ and meta-iodobenzylguanidine

Background  

Therapeutic options to effectively inhibit growth and spread of neuroendocrine gastrointestinal tumors are still limited. As both meta-iodobenzylguanidine (MIBG) and interferon-γ (IFNγ) cause antineoplastic effects in neuroendocrine gastrointestinal tumor cells, we investigated the antiproliferative effects of the combination of IFNγ and non-radiolabeled MIBG in neuroendocrine gut STC-1 and pancreatic carcinoid BON tumor cells.