In vitro comparative study of the antitumor effects of human interferon-alpha, beta and gamma on the growth and invasive potential of human melanoma cells

Bispecific Antibodies for IFN-β Delivery to ErbB2+ Tumors

The main aim of our work was to create a full-length bispecific antibody (BsAb) as a vehicle for the targeted delivery of interferon-beta (IFN-β) to ErbB2+ tumor cells in the form of non-covalent complex of BsAb and IFN-β. Such a construct is a CrossMab-type BsAb, consisting of an ErbB2-recognizing trastuzumab moiety, a part of chimeric antibody to IFN-β, and human IgG1 Fc domain carrying knob-into-hole amino acid substitutions necessary for the proper assembly of bispecific molecules. The IFN-β- recognizing arm of BsAb not only forms a complex with the cytokine but neutralizes its activity, thus providing a mechanism to avoid the side effects of the systemic action of IFN-β by blocking IFN-β Interaction with cell receptors in the process of cytokine delivery to tumor sites. Enzyme sandwich immunoassay confirmed the ability of BsAb to bind to human IFN-β comparable to that of the parental chimeric mAb. The BsAb binds to the recombinant ErbB2 receptor, as well as to lysates of ErbB2+ tumor cell lines. The inhibition of the antiproliferative effect of IFN-β by BsAb (IC50 = 49,3 µg/mL) was demonstrated on the HT29 cell line. It can be proposed that the BsAb obtained can serve as a component of the immunocytokine complex for the delivery of IFN-β to ErbB2-associated tumor cells.

Interferon-γ regulates cell malignant growth via the c-Abl/HDAC2 signaling pathway in mammary epithelial cells

Interferon-γ (IFN-γ) has been used to control cancers in clinical treatment. However, an increasing number of reports have suggested that in some cases effectiveness declines after a long treatment period, the reason being unclear. We have reported previously that long-term IFN-γ treatment induces malignant transformation of healthy lactating bovine mammary epithelial cells (BMECs) in vitro. In this study, we investigated the mechanisms underlying the malignant proliferation of BMECs under IFN-γ treatment. The primary BMECs used in this study were stimulated by IFN-γ (10 ng/mL) for a long term to promote malignancy. We observed that IFN-γ could promote malignant cell proliferation, increase the expression of cyclin D1/cyclin-dependent kinase 4 (CDK4), decrease the expression of p21, and upregulate the expression of cellular-abelsongene (c-Abl) and histone deacetylase 2 (HDAC2). The HDAC2 inhibitor, valproate (VPA) and the c-Abl inhibitor, imatinib, lowered the expression level of cyclin D1/CDK4, and increased the expression level of p21, leading to an inhibitory effect on IFN-γ-induced malignant cell growth. When c-Abl was downregulated, the HDAC2 level was also decreased by promoted proteasome degradation. These data suggest that IFN-γ promotes the growth of malignant BMECs through the c-Abl/HDAC2 signaling pathway. Our findings suggest that long-term application of IFN-γ may be closely associated with the promotion of cell growth and even the carcinogenesis of breast cancer.

Interferon-β sensitizes human malignant melanoma cells to temozolomide-induced apoptosis and autophagy

Malignant melanoma is a highly aggressive skin cancer that is highly resistant to chemotherapy. Adjuvant therapy is administered to patients with melanoma that possess no microscopic metastases or have a high risk of developing microscopic metastases. Methylating agents, including dacarbazine (DTIC) and temozolomide (TMZ), pegylated interferon (IFN)‑α2b and interleukin‑2 have been approved for adjuvant immuno‑chemotherapy; however, unsatisfactory results have been reported following the administration of methylating agents. IFN‑β has been considered to be a signaling molecule with an important therapeutic potential in cancer. The aim of the present study was to elucidate whether antitumor effects could be augmented by the combination of TMZ and IFN‑β in malignant melanoma. We evaluated the efficacy of TMZ and IFN‑β by comparing O6‑methylguanine‑DNA transferase (MGMT)‑proficient and ‑deficient cells, as MGMT has been reported to be associated with the resistance to methylating agents. Cell viability was determined by counting living cells with a Coulter counter, and apoptosis was analyzed by dual staining with Annexin V Alexa Fluor® 488 and propidium iodide. The expression of proteins involved in the cell cycle, apoptosis and autophagy was evaluated by western blot analysis. The combined treatment with TMZ and IFN‑β suppressed cell proliferation and induced cell cycle arrest. We also demonstrated that a combination of TMZ and IFN‑β enhanced apoptosis and autophagy more efficiently compared with TMZ treatment alone. These findings suggest that antitumor activity may be potentiated by IFN‑β in combination with TMZ.

Role of interferon in melanoma: old hopes and new perspectives

INTRODUCTION

Interferons (IFNs) play a key role in modulating anti-microbial and antitumor immune responses. In oncology, past attempts to exploit IFNs therapeutically did not fulfill expectations, and had only modest clinical results, mostly limited to adjuvant melanoma treatment. The recent successes of immunotherapy in oncology have brought new attention to the potential of immune-modulatory agents like the IFNs. Areas covered: The authors review the biological effects of IFN on melanoma and immune cells. Then, the authors summarize the clinical results of adjuvant and therapeutic IFN in melanoma, giving focus to possible prognostic factors and new on-going clinical trials. Expert opinion: IFNs offer intriguing opportunities for synergism between conventional treatments and recently introduced molecular-targeted and immunotherapy approaches. However, the full comprehension of all IFN effects and their multiple biologic links is challenging. A strong commitment toward parallel translational research is needed to facilitate the interpretation of IFN's expected and unexpected effects, guiding the rational design of informative clinical studies.

Autophagy mediated by arginine depletion activation of the nutrient sensor GCN2 contributes to interferon-γ-induced malignant transformation of primary bovine mammary epithelial cells

Autophagy has been linked to the regulation of both the prevention and progression of cancer. IFN-γ has been shown to induce autophagy in multiple cell lines in vitro. However, whether IFN-γ can induce autophagy and whether autophagy promotes malignant transformation in healthy lactating bovine mammary epithelial cells (BMECs) remain unclear. Here, we provide the first evidence of the correlation between IFN-γ treatment, autophagy and malignant transformation and of the mechanism underlying IFN-γ-induced autophagy and subsequent malignant transformation in primary BMECs. IFN-γ levels were significantly increased in cattle that received normal long-term dietary corn straw (CS) roughage supplementation. In addition, an increase in autophagy was clearly observed in the BMECs from the mammary tissue of cows expressing high levels of IFN-γ. In vitro, autophagy was clearly induced in primary BMECs by IFN-γ within 24 h. This induced autophagy could subsequently promote dramatic primary BMEC transformation. Furthermore, we found that IFN-γ promoted arginine depletion, activated the general control nonderepressible-2 kinase (GCN2) signalling pathway and resulted in an increase in autophagic flux and the amount of autophagy in BMECs. Overall, our findings are the first to demonstrate that arginine depletion and kinase GCN2 expression mediate IFN-γ-induced autophagy that may promote malignant progression and that immunometabolism, autophagy and cancer are strongly correlated. These results suggest new directions and paths for preventing and treating breast cancer in relation to diet.

Difference of interferon-α and interferon-β on melanoma growth and lymph node metastasis in mice

Interferon (IFN)-α and IFN-β are type I IFNs which are known to exert an antitumor effect on malignant melanoma. The aim of this study was to evaluate and compare the efficacy of IFN-α2b and IFN-β1a on primary tumor growth and lymph node metastasis, and to examine the mechanisms of lymph node metastasis. The efficacy of IFN-α2b and IFN-β1a was evaluated using a human melanoma xenograft model. We further examined the effect of IFNs on lymphangiogenic growth factors in human melanoma cells. IFN-β1a showed a stronger antiproliferative and proapoptotic effect, whereas IFN-α2b inhibited tumor growth and lymph node metastasis through inhibition of lymphangiogenesis. Both IFN-α2b and IFN-β1a were effective in inhibiting lymph node metastasis compared with the control. Microvessel density decreased in tumors treated with IFN-α2b and IFN-β1a compared with the control, without statistical significance. Lymphatic vessel density decreased significantly only in tumors treated with IFN-α2b (P<0.05). Both IFN-α2b and IFN-β1a decreased in-vitro and in-vivo vascular endothelial growth factor (VEGF)-C and VEGF receptor-3 protein expression and secretory VEGF-C level in vitro. IFN-α2b showed an earlier and sustained effect in decreasing VEGF-C and VEGF receptor-3 protein expression and a superior effect in decreasing the secretory VEGF-C level compared with IFN-β1a. Our investigation shows that both IFN-α2b and IFN-β1a exerted different antitumor and antimetastatic effects in human melanoma xenograft. Moreover, the present findings indicate that inhibition of lymphangiogenesis is another possible antimetastatic action mechanism of IFN-α2b.

Type I interferons: key players in normal skin and select cutaneous malignancies

Interferons (IFNs) are a family of naturally existing glycoproteins known for their antiviral activity and their ability to influence the behavior of normal and transformed cell types. Type I Interferons include IFN- α and IFN- β . Currently, IFN- α has numerous approved antitumor applications, including malignant melanoma, in which IFN- α has been shown to increase relapse free survival. Moreover, IFN- α has been successfully used in the intralesional treatment of cutaneous squamous cell carcinoma (SCC) and basal cell carcinoma (BCC). In spite of these promising clinical results; however, there exists a paucity of knowledge on the precise anti-tumor action of IFN- α / β at the cellular and molecular levels in cutaneous malignancies such as SCC, BCC, and melanoma. This review summarizes current knowledge on the extent to which Type I IFN influences proliferation, apoptosis, angiogenesis, and immune function in normal skin, cutaneous SCC, BCC, and melanoma.

IFNB1/interferon-β-induced autophagy in MCF-7 breast cancer cells counteracts its proapoptotic function

IFNB1/interferon (IFN)-β belongs to the type I IFNs and exerts potent antiproliferative, proapoptotic, antiangiogenic and immunemodulatory functions. Despite the beneficial effects of IFNB1 in experimental breast cancers, clinical translation has been disappointing, possibly due to induction of survival pathways leading to treatment resistance. Defects in autophagy, a conserved cellular degradation pathway, are implicated in numerous cancer diseases. Autophagy is induced in response to cancer therapies and can contribute to treatment resistance. While the type II IFN, IFNG, which in many aspects differs significantly from type I IFNs, can induce autophagy, no such function for any type I IFN has been reported. We show here that IFNB1 induces autophagy in MCF-7, MDAMB231 and SKBR3 breast cancer cells by measuring the turnover of two autophagic markers, MAP1LC3B/LC3 and SQSTM1/p62. The induction of autophagy in MCF-7 cells occurred upstream of the negative regulator of autophagy MTORC1, and autophagosome formation was dependent on the known core autophagy molecule ATG7 and the IFNB1 signaling molecule STAT1. Using siRNA-mediated silencing of several core autophagy molecules and STAT1, we provide evidence that IFNB1 mediates its antiproliferative effects independent of autophagy, while the proapoptotic function of IFNB1 was strongly enhanced in the absence of autophagy. This suggests that autophagy induced by IFNB1 promoted survival, which might contribute to tumor resistance against IFNB1 treatment. It may therefore be clinically relevant to reconcile a role for IFNB1 in the treatment of breast cancer with concomitant inhibition of autophagy.

Anti-tumor effect of adipose tissue derived-mesenchymal stem cells expressing interferon-β and treatment with cisplatin in a xenograft mouse model for canine melanoma

Adipose tissue-derived mesenchymal stem cells (AT-MSCs) are attractive cell-therapy vehicles for the delivery of anti-tumor molecules into the tumor microenvironment. The innate tropism of AT-MSCs for tumors has important implications for effective cellular delivery of anti-tumor molecules, including cytokines, interferon, and pro-drugs. The present study was designed to determine the possibility that the combination of stem cell-based gene therapy with low-dose cisplatin would improve therapeutic efficacy against canine melanoma. The IFN-β transduced canine AT-MSCs (cAT-MSC-IFN-β) inhibited the growth of LMeC canine melanoma cells in direct and indirect in vitro co-culture systems. In animal experiments using BALB/c nude mouse xenografts, which developed by injecting LMeC cells, the combination treatment of cAT-MSC-IFN-β and low-dose cisplatin significantly reduced tumor volume compared with the other treatment groups. Fluorescent microscopic analysis with a TUNEL (terminal deoxynucleotidyl transferase-mediated nick-end labeling) assay of tumor section provided evidence for homing of cAT-MSC-IFN-β to the tumor site and revealed that the combination treatment of cAT-MSC-IFN-β with low-dose cisplatin induced high levels of cell apoptosis. These findings may prove useful in further explorations of the application of these combined approaches to the treatment of malignant melanoma and other tumors.

Sequential local injection of low-dose interferon-beta for maintenance therapy in stage II and III melanoma: a single-institution matched case-control study

OBJECTIVE

To determine the beneficial effect of maintenance therapy in stage II and III melanoma by sequential local injection of low-dose interferon-β.

METHODS

We reviewed 46 patients with stage II and III primary melanoma at our institution from 2004 through 2009. Twenty-one patients were treated with interferon-β maintenance therapy consisting of subcutaneous injection of natural interferon-β at a dose of 3 × 10(6) IU/day for 10 consecutive days, and 25 patients underwent observation alone.

RESULTS

Compared with all patients, overall survival and relapse-free survival were significantly worse in the observation group than in the interferon-β group (p = 0.024 and 0.029, respectively). In stage II, a significant difference in overall survival, but not in relapse-free survival, was seen between the two groups (p = 0.041). When the interferon-β group was stratified by subgroup, there was a statistical difference only between dosage and duration (p = 0.027 and p < 0.001, respectively).

CONCLUSIONS

This study demonstrates that maintenance therapy by interferon-β is beneficial in the outcome of the disease without substantial toxic effects, especially in patients with stage II melanoma. Extension of the duration of treatment beyond 2 years could further improve the therapeutic efficacy of interferon-β.

Anti-tumor effects of canine adipose tissue-derived mesenchymal stromal cell-based interferon-β gene therapy and cisplatin in a mouse melanoma model

BACKGROUND AIMS

Adipose tissue (AT)-derived mesenchymal stromal cells (MSC) (AT-MSC) represent a novel tool for delivering therapeutic genes to tumor cells. Interferon (IFN)-β is a cytokine with pleiotropic cellular functions, including anti-proliferative, immunomodulatory and anti-angiogenic activities. The purpose of this study was to engineer canine AT-MSC (cAT-MSC) producing IFN-β and to evaluate the anti-tumor effect of cAT-MSC-IFN-β combined with cisplatin in mouse melanoma model.

METHODS

cAT-MSC engineered to express mouse IFN-β were generated using a lentiviral vector (cAT-MSC-IFN-β) and the secreted IFN-β-induced inhibition of tumor cell growth and apoptosis on B16F10 cells was investigated in vitro prior to in vivo studies. Melanoma-bearing mouse was developed by injecting B16F10 cells subcutaneously into 6-week-old C57BL/6 mice. After 14 days, cisplatin (10 mg/kg) was injected intratumorally, and 3 days later the engineered cAT-MSC were injected subcutaneously every 3 days to death. Tumor volume and survival times were measured.

RESULTS

The combination treatment of cAT-MSC-IFN-β with cisplatin was more effective in inhibiting the growth of melanoma and resulted in significantly extended survival time than both an unengineered cAT-MSC-cisplatin combination group and a cisplatin-alone group. Interestingly, subcutaneously injected cAT-MSC-IFN-β were migrated to tumor sites.

CONCLUSIONS

Our data suggest that canine AT-MSC could serve as a powerful cell-based delivery vehicle for releasing therapeutic proteins to tumor lesions. Maximal anti-tumor effects were seen when this therapy was combined with a DNA-damaging chemotherapeutic agent. This study demonstrates the possible applicability of AT-MSC-mediated IFN-β in treating canine and human cancer patients.

Effects of type I interferons on IGF-mediated autocrine/paracrine growth of human neuroendocrine tumor cells

We recently demonstrated that interferon (IFN)-beta has a more potent antitumor activity than IFN-alpha in BON cells, a neuroendocrine tumor (NET) cell line. The present study showed the role of type I IFNs in the modulation of the insulin-like growth factor (IGF) system in NETs. BON cells expressed IGF-I, IGF-II, IGF-I receptor, and insulin receptor mRNA. In addition, IGF-I and IGF-II stimulated the proliferation of BON cells and induced an inhibition of DNA fragmentation (apoptosis). As evaluated by quantitative RT-PCR, treatment with IFN-alpha (100 IU/ml) or IFN-beta (100 IU/ml) inhibited the expression of IGF-II mRNA (-42% and -65%, respectively, both P < 0.001), whereas IGF-I receptor mRNA was significantly upregulated by IFN-alpha (+28%, P < 0.001) and downregulated by IFN-beta (-47%, P < 0.001). Immunoreactive IGF-II concentration decreased in the conditioned medium during IFN-alpha (-16%, P < 0.05) and IFN-beta (-69%, P < 0.001) treatment. Additionally, IGF-I receptor bioactivity was reduced (-54%) after IFN-beta treatment. Scatchard analysis of (125)I-labeled IGF-I binding to cell membrane of BON cells revealed a dramatic suppression of maximum binding capacity only in the presence of IFN-beta. Finally, the proapoptotic activity of IFN-beta was partially counteracted by the coadministration of IGF-I and IGF-II (both at 50 nM). In conclusion, these data demonstrate that the IGF system has an important role in autocrine/paracrine growth of BON cells. The more potent antitumor activity of IFN-beta compared with IFN-alpha could be explained by several effects on this system: 1) both IFNs inhibit the transcription of IGF-II, but the suppression is significantly higher after IFN-beta than IFN-alpha and 2) only IFN-beta inhibits the expression of IGF-I receptor.

Interferon-beta therapy for malignant melanoma: the dose is crucial for inhibition of proliferation and induction of apoptosis of melanoma cells

We investigated the anti-tumor effect of human interferon-beta (HuIFN-beta) against malignant melanoma. In vitro study revealed that HuIFN-beta not only inhibited proliferation of melanoma cells (seven cell lines: MM-AN, MM-BP, MM-LH, MM-RU, PM-WK, RPM-EP, RPM-MC) but also induced apoptosis in a dose dependent fashion, though the sensitivity to HuIFN-beta was different among cell lines. In addition, we administered HuIFN-beta into cutaneous metastatic lesions of melanoma and evaluated clinical and histopathological effects. Although the size of the metastatic cutaneous lesion did not change by the intralesional injection of HuIFN-beta, histopathological examination revealed apoptotic changes of melanoma cells along with dense lymphohistiocytic infiltration. The present study confirmed direct and indirect inhibitory effects of HuIFN-beta on human melanoma cells and suggests that local higher concentration of HuIFN-beta is needed to eradicate melanoma lesions.

Inhibition of in vitro tumor cell proliferation by cytokines induced by combinations of TLR or TLR and TCR agonists

The objective of this study was to learn from in vitro studies how to better utilize Toll-like receptor (TLR) agonists in controlling tumor growth. One of the primary effects of TLR agonists is induction of cytokine and chemokine production. In order to identify combinations of cytokines or chemokines with optimal ability to inhibit in vitro tumor cell proliferation, a panel of 17 recombinant human or mouse cytokines that have minimal effect on primary cell survival, were tested individually or in combinations of 2, 3 or 4 on a panel of human and mouse chemotherapy sensitive and resistant tumor cell lines. A combination of high (>10 ng/ml) levels of IFNgamma with moderate concentrations of TNFalpha>IFNalpha>IL-6=IL-8 was most effective at inhibiting in vitro tumor cell viability and proliferation with minimal effect on primary cells. We also observed that similar cytokine profile could be induced in vitro PBMC culture by using certain combinations of TLR-TLR and TLR-TCR agonists. Thus, concomitant activation of TLR7/8 with TLR4 or TLR 7/8 with T cell receptor (TCR) in PBMC, amongst all possible paired TLR-TLR and TLR-TCR agonist combinations, produced cytokine mix high in IFNgamma, in combination with IFNalpha, IL-6, IL-8, TNFalpha. Such cytokine mix was equal or more effective tumor cell killing and inhibition of tumor cell proliferation than the best rec-cytokine mixture tested. These results suggest that, TLR and/or TCR agonists combinations generate an optimal mixture of cytokines and chemokines competent in regulating in vitro tumor growth, and imply that realizing such "right cytokine induction" in vivo might be more efficacious than that with individual cytokines or TLR agonists induced cytokine mix.

Continuous delivery of human type I interferons (α/β) has significant activity against acute myeloid leukemia cells in vitro and in a xenograft model

In this study, we focused primarily on the antileukemic activity of interferon-β (IFN-β) in a murine xenograft model of acute myeloid leukemia (AML). Bolus administration of recombinant IFN-β via the subcutaneous or intravenous route failed to show efficacy in mice injected with AML cells despite achieving peak plasma IFN-β levels of more than 200 IU/mL. In contrast, stable expression of IFN-β following adeno-associated virus (AAV) vector–mediated gene transfer resulted in significant antileukemic activity against primary AML cells derived from patients with poor prognostic markers. An almost linear relationship was observed with stable plasma levels of IFN-β and antileukemic activity in mice. Even levels below 10 IU/mL were able to reduce tumor load by 50-fold when compared with control animals. These levels of IFN-β are likely to be nontoxic in humans. Therefore, approaches capable of maintaining stable plasma levels of IFN-β merit further clinical evaluation in patients with AML.

IFN-beta is a highly potent inhibitor of gastroenteropancreatic neuroendocrine tumor cell growth in vitro

IFN-alpha controls hormone secretion and symptoms in human gastroenteropancreatic neuroendocrine tumors (GEP-NET) but it rarely induces a measurable tumor size reduction. The effect of other type I IFNs, e.g., IFN-beta, has not been evaluated. We compared the antitumor effects of IFN-alpha and IFN-beta in BON cells, a functioning human GEP-NET cell line. As determined by quantitative reverse transcription-PCR analysis and immunocytochemistry, BON cells expressed the active type I IFN receptor mRNA and protein (IFNAR-1 and IFNAR-2c subunits). After 3 and 6 days of treatment, IFN-beta significantly inhibited BON cell growth in a time- and dose-dependent manner. IC50 and maximal inhibitory effect on day 6 were 8 IU/mL and 98%, respectively. In contrast, the effect of IFN-alpha resulted significantly in a less potent effect (IC50: 44 IU/mL, maximal inhibition: 26%). IFN-alpha induced only cell cycle arrest, with an accumulation of the cells in S phase. IFN-beta, apart from a more potent delay in S-G2-M phase transit of the cell cycle, also induced a strong stimulation of apoptosis, evaluated by flow cytometry (Annexin V and 7-AAD) and measurement of the DNA fragmentation. Besides, only IFN-beta severely suppressed chromogranin A levels in the medium from BON cells after 6 days of treatment. In conclusion, IFN-beta is much more potent, compared with IFN-alpha, in its inhibitory effect on GEP-NET cell proliferation in vitro through the induction of apoptosis and cell cycle arrest. Further studies are required to establish whether IFN-beta has comparable potent tumor growth inhibitory effects in vivo.

Interferon-gamma and anti-Fas antibody-induced apoptosis in human melanoma cell lines and its relationship to bcl-2 cleavage and bak expression

Interferon-gamma (IFNgamma) has been shown to induce apoptosis through the induction of the Fas antigen in certain cell lines. In this study, we used four melanoma cell lines (MMN9, PMP, MAA and HMG) to study the antiproliferative effect of exogenous IFNgamma treatment, the expression of IFNgamma-induced Fas antigen, and the combined effect of IFNgamma and anti-Fas antibody (CH-11). We also investigated the relationship between Fas-mediated apoptosis and the expression of the bcl-2 family, measured using Western blotting. IFNgamma increased the mean fluorescence intensity of Fas in MMN9 and PMP cells as measured by flow cytometry. Combined therapy had a significant antiproliferative effect on MMN9 and PMP cells, as measured by the MTT assay. After exposure to IFNgamma and anti-Fas antibody, cleavage of bcl-2 occurred in apoptotic cells, and the signal intensity of both bcl-2 and bak decreased in surviving MMN9 cells, as shown by Western blotting analysis. Our results indicate that IFNgamma induces overexpression of Fas and consequently enhances the sensitivity of melanoma cells to Fas-mediated apoptosis. Furthermore, it is possible that cleavage of bcl-2 correlates with the induction of apoptosis induced by IFNgamma and anti-Fas antibody in melanoma cells. We conclude that combined therapy with IFNgamma and anti-Fas antibody may provide an alternative and more efficient chemotherapeutic approach against melanoma cells by inducing the overexpression of Fas after exposure to IFNgamma.

Interferon-? Is More Potent Than Interferon-? in Inhibition of Human Hepatocellular Carcinoma Cell Growth When Used Alone and in Combination With Anticancer Drugs

BACKGROUND

The prognosis of advanced hepatocellular carcinoma (HCC) is extremely poor, but promising effects of chemotherapies combined with interferon (IFN) have been reported.

METHODS

To develop more effective combination therapies for HCC, we compared the antiproliferative effects of IFN-alpha and IFN-beta in combination with various cytotoxic drugs on hepatoma cell lines using MTT assay and isobologram analysis.

RESULTS

IFN-beta was more potent than IFN-alpha in inhibiting the cell growth of all cell lines (P <.05, two-way ANOVA). PLC/PRF/5 was more sensitive to either IFN, than HLE and HuH7. Cell growth of all cell lines was inhibited in a dose-dependent manner by 5-fluorouracil (5-FU), cisplatin (CDDP), and doxorubicin (DOX), but the sensitivities of these cells were considerably different. As for IFN-alpha, synergistic effects were observed when combined with 5-FU and DOX on PLC/PRF/5 cells only, whereas IFN-beta showed synergistic effects with 5-FU and CDDP on HuH7 and PLC/PRF/5 cell lines.

CONCLUSION

The spectra of the antiproliferative activity and synergistic effect of IFN-beta when combined with anticancer drugs are more potent than those of IFN-alpha. Combinations of IFN-beta and anticancer drugs may provide a better treatment of HCC when combinations with IFN-alpha are ineffective.

Growth inhibition of human malignant melanoma transfected with the human interferon-beta gene by means of cationic liposomes

Among the various types of human interferons, human interferon-beta (HuIFNbeta) has the strongest anti-proliferative activity against human melanoma cell lines. Therefore, we investigated the growth inhibitory effect of a cationic liposome containing the HuIFNbeta gene on human melanoma cell lines in vitro and in vivo. After transfection with liposomes containing the HuIFN-beta gene, human melanoma cell lines produced HuIFNbeta in the culture medium at levels ranging from 67 to 3.8 IU/ml on day 6, and growth of the cells was inhibited by 71-92%. Moreover, six injections of liposomes containing the HuIFNbeta gene completely eradicated human melanoma nodules transplanted onto the backs of nude mice 40 days after the first injection. Histological analysis of the injected nodules revealed that the HuIFNbeta gene transfection induced apoptosis of the human melanoma cells. These data suggest that transfection of the HuIFNbeta gene using cationic liposomes is a promising candidate for gene therapy of human melanoma.

Intermediate dose recombinant interferon-alpha as second-line treatment for patients with recurrent cutaneous melanoma who were pretreated with low dose interferon

BACKGROUND

Interferon (IFN) is widely considered the most effective agent in the adjuvant therapy of patients with cutaneous melanoma (CM). However, little is known about the effect of IFN on pretreated CM patients who experience disease recurrence. The authors conducted a Phase II study to determine whether intermediate doses of IFN could be beneficial for these patients.

METHODS

A series of 24 consecutive CM patients who had undergone surgery for local, in-transit, or lymph node disease recurrence during adjuvant therapy with low dose IFN (IFNalpha-2b, 3 million units [MU] per day, three times per week) were enrolled for second-line therapy with intermediate dose IFN (IFNalpha-2b, 10 MU per day) for one year.

RESULTS

IFN was discontinued in 7 patients (29.2%) because of toxicity. Several patients complained of impairment in their daily activities. Progression of disease was registered in 17 patients (70. 8%), with a median disease free survival of 5.5 months (95% confidence interval, 3.4-14.2). The median follow-up for the 7 patients who did not experience disease recurrence was 15 months (range, 13-22 months).

CONCLUSIONS

An increased dose of IFN as second-line adjuvant treatment was poorly tolerated and produced negative clinical outcomes in patients with CM. However, these patients probably were unresponsive to IFN regardless of the dosage level. In fact, the first adjuvant IFN treatment was ineffective in all patients. Thus, the key factor in the treatment of CM seems to be patient responsiveness to IFN rather than the total dosage achieved.

Interferon (IFN)-beta gene transfer into TS/A adenocarcinoma cells and comparison with IFN-alpha: differential effects on tumorigenicity and host response

Our group had previously shown that transfer of the mouse interferon (IFN)-alpha1 gene into the metastasizing TS/A mammary adenocarcinoma resulted in T-cell-mediated tumor rejection and development of antitumor immunity. Moreover, we had shown that the metastatic ability of TS/A tumor cells producing IFN-alpha was strongly impaired, whereas IFN-gamma expression did not influence or augmented metastasis formation by TS/A cells. In this study, we have analyzed the in vitro and in vivo behavior of various TS/A tumor cell clones isolated after the transduction with a recombinant retroviral vector carrying the mouse IFN-beta gene. We have also compared the tumorigenicity of these clones with that of TS/A cells expressing IFN-alpha1. BALB/c mice were inoculated subcutaneously with parental TS/A cells, transduction control TS/A cells, or TS/A cells producing IFN-alpha or IFN-beta. Tumor growth was evaluated by the measurement of tumor masses and analysis of survival. The features of tumor growth and rejection were examined by histological and immunohistochemical analyses. The metastatic ability of parental TS/A cells, transduction control TS/A cells, or TS/A cells producing IFN-alpha, IFN-beta, or IFN-gamma was evaluated after intravenous injection of the tumor cells into BALB/c mice by counting of the lung metastatic nodules and analysis of survival. A strong inhibition of tumorigenicity and development of tumor immunity were observed upon subcutaneous injection of syngeneic mice with TS/A tumor cells producing high amounts of IFN-beta, but not with clones expressing low levels of the cytokine, as observed for cells expressing IFN-alpha. IFN-alpha secretion by TS/A cells at the site of tumor growth induced a stronger inflammatory response as compared with IFN-beta, which appeared to be more active in the inhibition of tumor-induced angiogenesis. Notably, the metastatic ability of IFN-beta-producing TS/A cells after intravenous injection was either not affected or only slightly impaired as compared with parental TS/A tumor cells. In contrast, even cells producing low levels of IFN-alpha proved to be poorly metastatic. These findings represent the first comparison of the effectiveness of IFN-alpha versus IFN-beta produced by genetically modified cells on their tumorigenic behavior and suggest the existence of some notable differences in the capabilities of these two cytokines to induce a host antitumor reactivity in mice.