Antiproliferative effects of interferons on human melanoma cells in the human tumor colony-forming assay

Interferon Gamma-Inducible NAMPT in Melanoma Cells Serves as a Mechanism of Resistance to Enhance Tumor Growth

(1) Background: Immune cells infiltrate the tumor microenvironment and secrete inflammatory cytokines, including interferons (IFNs), to drive antitumor responses and promote tumor clearance. However, recent evidence suggests that sometimes, tumor cells can also harness IFNs to enhance growth and survival. The essential NAD+ salvage pathway enzyme nicotinamide phosphoribosyltransferase (NAMPT) gene is constitutively expressed in cells during normal homeostasis. However, melanoma cells have higher energetic demands and elevated NAMPT expression. We hypothesized that interferon gamma (IFNγ) regulates NAMPT in tumor cells as a mechanism of resistance that impedes the normal anti-tumorigenic effects of IFNγ. (2) Methods: Utilizing a variety of melanoma cells, mouse models, Crispr-Cas9, and molecular biology techniques, we explored the importance of IFNγ-inducible NAMPT during melanoma growth. (3) Results: We demonstrated that IFNγ mediates the metabolic reprogramming of melanoma cells by inducing Nampt through a Stat1 binding site in the Nampt gene, increasing cell proliferation and survival. Further, IFN/STAT1-inducible Nampt promotes melanoma in vivo. (4) Conclusions: We provided evidence that melanoma cells directly respond to IFNγ by increasing NAMPT levels, improving their fitness and growth in vivo (control n = 36, SBS KO n = 46). This discovery unveils a possible therapeutic target that may improve the efficacy of immunotherapies involving IFN responses in the clinic.

Antibody-Based Targeting of Interferon-Beta-1a Mutein in HER2-Positive Cancer Enhances Antitumor Effects Through Immune Responses and Direct Cell Killing

Type I interferon (IFN) has been approved as an anticancer agent to treat some malignancies. However, IFNs have a short in vivo half-life, systemic toxicity, and poor biophysical properties, which prevent it from being widely used for cancer therapy. This study aimed to construct recombinant IFN-β-1a mutein immunocytokines that comprise a human epidermal growth factor receptor 2 (HER2)-targeting antibody and IFN-β muteins with an additional glycosylation, which can overcome the limitation of the cytokine itself. Hence, the molecular design aims to 1) enhance productivity and biophysical properties by adding secondary glycosylation in IFN-β, 2) increase the therapeutic index of IFN-β therapy by preferential retention at the tumor by possessing high affinity for HER2-expressing cancer cells, and 3) improve the pharmacokinetics and, thus, the convenience of IFN-β administration. The yield of trastuzumab-IFN-β mutein was higher than that of trastuzumab-wild-type IFN-β in the mammalian cell culture system. Trastuzumab-IFN-β mutein showed similar IFN activity and HER2-targeting ability equivalent to that of IFN-β mutein and trastuzumab, respectively. Trastuzumab-IFN-β mutein directly inhibited the growth of HER2-positive gastric cancer cell lines and was more effective than trastuzumab or IFN-β mutein alone. Trastuzumab-IFN-β mutein and IFN-β mutein displayed enhanced immune cell-mediated cytotoxicity. Collectively, trastuzumab-IFN-β mutein may have indirect immune cell-mediated antitumor effects and direct cell growth inhibitory effects. Tumor-targeting effect of trastuzumab-IFN-β mutein was analyzed using in vivo fluorescence imaging. The accumulation of trastuzumab-IFN-β mutein was observed in HER2-positive tumors rather than other tissues except the liver. To evaluate the both direct tumor growth inhibition effect and indirect immune cell-mediated antitumor effect, we tested the effect of trastuzumab-IFN-β mutein in HER2-positive cancer xenograft models using nude mice or humanized mice. Trastuzumab-IFN-β mutein could significantly enhance tumor regression when compared with trastuzumab or IFN-β mutein. In addition, an increase in tumor-infiltrating lymphocytes was observed in the trastuzumab-IFN-β mutein-treated group, implying that the tumor-targeting IFN-β may have an enhanced antitumor effect through increased immune response. Therefore, targeting IFN-β with an anti-HER2 monoclonal antibody makes the immunocytokine more potent than either agent alone. These novel findings suggest that trastuzumab-IFN-β mutein merits clinical evaluation as a new candidate of anticancer therapeutics.

Insights into cytokine-receptor interactions from cytokine engineering

Cytokines exert a vast array of immunoregulatory actions critical to human biology and disease. However, the desired immunotherapeutic effects of native cytokines are often mitigated by toxicity or lack of efficacy, either of which results from cytokine receptor pleiotropy and/or undesired activation of off-target cells. As our understanding of the structural principles of cytokine-receptor interactions has advanced, mechanism-based manipulation of cytokine signaling through protein engineering has become an increasingly feasible and powerful approach. Modified cytokines, both agonists and antagonists, have been engineered with narrowed target cell specificities, and they have also yielded important mechanistic insights into cytokine biology and signaling. Here we review the theory and practice of cytokine engineering and rationalize the mechanisms of several engineered cytokines in the context of structure. We discuss specific examples of how structure-based cytokine engineering has opened new opportunities for cytokines as drugs, with a focus on the immunotherapeutic cytokines interferon, interleukin-2, and interleukin-4.

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.

Gene regulatory and clinical effects of interferon β in patients with metastatic melanoma: a phase II trial

Interferon (IFN)-β in preclinical studies, compared to IFN-α2, bound with higher affinity to its receptor, induced to higher levels of IFN-stimulated gene products, induced more apoptosis in melanoma cells, and had antitumor effects against melanoma. A maximally tolerated dose of 12 × 10(6) international units/m(2) after 2 weeks subcutaneously daily with dose escalation to 18 × 10(6) international units/m(2) was thus used in a phase II trial of IFN-β1a in cutaneous metastatic melanoma (n = 17) and uveal melanoma (n = 4). It resulted in expected but reversible drug-related severe (grade 3) adverse events in 13/21 patients; anorexia and fatigue were mostly of mild or moderate severity and infrequently needed dose reduction. Although a single patient had a sustained regression, overall IFN-β1a did not have clinical benefit (response rate <10%; median progression-free survival 1.8 months). Effective and potent induction in peripheral blood cells and into serum of products of IFN-stimulated genes such as the pro-apoptotic cytokine, TRAIL, and the immunomodulatory and anti-angiogenic chemokines, CXCL10 and CCL8, confirmed gene regulatory actions. To probe further anti-angiogenic mechanisms, both VEGF-A and CXCL-5 were assessed; compared to before treatment, both proteins decreased. Continued improvements in understanding of antitumor mechanisms will enhance usefulness of IFNs for nodal or distant metastases from melanoma.

Augmentation of effects of interferon-stimulated genes by reversal of epigenetic silencing: potential application to melanoma

Increased expression of genes, silenced by methylation of their promoters, could have relevance for increasing effects of not only interferons (IFNs) but also APO2L/TRAIL, cytotoxics and immunotherapeutics for melanoma and other malignancies. A resistant melanoma cell line, A375, lacked APO2L/TRAIL or apoptosis induction by either IFN-alpha2 or IFN-beta. However, apoptosis was induced by IFNs in A375 cells by 5-aza,2'-deoxycytidine (5-Aza-dC), evaluated based upon the postulate that promoter methylation might be silencing pro-apopoptotic IFN-stimulated genes (ISGs). RASSF1A, commonly methylated at high frequency in many tumors including melanoma, which we discovered to be also an IFN-regulated gene, was increased by 5-Aza-dC. RASSF1A was important in enhancing apoptotic effects of not only IFNs and APO2L/TRAIL but also cisplatin. Unraveling epigenetic regulatory mechanisms, as yet only partially identified, will result in new biological insights and improved strategies for therapeutic use of IFNs or ISGs such as APO2L/TRAIL.

An update on malignant melanoma vaccine research: insights into mechanisms for improving the design and potency of melanoma therapeutic vaccines

Currently, cancer vaccine therapy for melanoma has a 2-fold focus. On the one hand, advances have been aimed at improving the effectiveness of melanoma vaccines based on a greater understanding of melanoma tumor cell biology. On the other hand, there is increasing evidence that the immune system, our defense against tumors, also inadvertently plays a supportive role in promoting the development and progression of tumors. Hence, two opposing forces 'hanging in the balance' dictate patients' responses to melanoma: tumor cell biology and the status of the immune system. Recent developments in our understanding of both of these aspects have provided new leads and insights for novel ways to improve vaccine design and add to the melanoma vaccine armory. As the focus of immunotherapy shifts its aim towards the tumor microenvironment, we are now developing the ability to program the immune responses raised by vaccination against melanoma. The aim here is to prevent myeloid and regulatory T-cell-mediated immune suppression as well as to counteract tumor-derived factors capable of suppressing immune responses. A redirected strategy for vaccine immunotherapy is proposed based on our greater understanding of tumor immunity. Using a combination therapy of immune-potentiating melanoma vaccines together with adjuvants for overcoming the immunosuppressive forces will allow us to activate protective immunity against melanoma. Other cancer vaccines (i.e. colon or renal) are already offering reasons for hope and expectation that vaccine immunotherapy will also produce successful outcomes for patients with melanoma.

Review: Milstein Award lecture: interferons and cancer: where from here?

Interferons (IFNs) remain the most broadly active cytokines for cancer treatment, yet ones for which the full potential is not reached. IFNs have impacted positively on both quality and quantity of life for hundreds of thousands of cancer patients with chronic leukemia, lymphoma, bladder carcinoma, melanoma, and renal carcinoma. The role of the IFN system in malignant pathogenesis continues to enhance understanding of how the IFN system may be modulated for therapeutic advantage. Reaching the full potential of IFNs as therapeutics for cancer will also result from additional understanding of the genes underlying apoptosis induction, angiogenesis inhibition, and influence on immunologic function. Food and Drug Administration (FDA) approval of IFNs occurred less than 20 years ago; after 40 years, third-generation products of early cytotoxics, such as 5- fluorouracil (5FU), are beginning to reach clinical approval. Thus, substantial potential exists for additional application of IFNs and IFN inducers as anticancer therapeutics, particularly when one considers that their pleiotropic cellular and molecular effects have yet to be fully defined.

Resistance to interferons in melanoma cells does not correlate with the expression or activation of signal transducer and activator of transcription 1 (Stat1)

Defects in expression or activation signal transducer and activator of transcription-1 (Stat1) in response to interferon-alpha2 (IFN-alpha2) have been implicated as a mechanism for IFN resistance in melanoma cells. To further determine the significance of this observation, 17 melanoma cell lines sensitive or resistant to the antiproliferative effects of IFN-alpha2 and IFN-beta, as well as 30 melanoma patient samples, were analyzed for Stat1 levels by either Western blot analysis or immunohistochemistry. Although the expression level varied between samples, all the cell lines except one and all melanoma biopsy specimens expressed Stat1. IFN-stimulated levels of Stat1 and Stat2, which constitute the transcriptional activation complexes, such as, gamma activated factor (GAF) and IFN-stimulated gene factor 3 (ISGF3), for IFN-stimulated gene (ISG) induction were assessed in melanoma cell lines. Both IFN-alpha2 and INF-beta induced equivalent amounts of Stat1 and Stat2 proteins in cell lines, although compared with IFN-alpha2, IFN-beta had greater antiproliferative effects. No significant differences were observed in tyrosine or serine phosphorylation of Stat1 or the formation of GAF or ISGF3 complexes following IFN-alpha2 or IFN-beta treatment of IFN-resistant or IFN-sensitive cell lines. Comparable induction of two ISGs, ISG54 and IFN regulatory factor-1 (IRF-1), was observed in both sensitive WM9 and resistant A375 cells. Therefore, we report that defects in expression or activation of Stat1 or Stat2 were infrequent in melanoma cell lines and tumor samples and did not correlate with IFN resistance. Cellular resistance to IFNs likely results from defective quantitative or qualitative expression of specific ISGs.

Second-generation interferons for cancer: clinical targets

IFNs were the first new therapeutic products resulting from recombinant DNA technology. IFNs were also the first human proteins effective in cancer treatment. There is however much to be discovered which will lead to new clinical applications. Areas which represent major research challenges for full understanding and application of the IFN system are: (i) the diversity of the IFN family; (ii) the role of induction; (iii) molecular mechanism of action; (iv) cellular modulatory effects; (v) advantages of combinations, and (vi) identification of new therapeutic indications. This review will emphasize the diversity of the IFN family and chemical modifications which will result in second-generation IFNs. Pre-clinical and clinical findings form the basis for new therapeutic directions in chronic myelogenous leukemia, lymphomas, myelomas, melanoma, urologic malignancies, primary brain tumors, and ovarian carcinoma.

Interferon-resistant human melanoma cells are deficient in ISGF3 components, STAT1, STAT2, and p48-ISGF3gamma

The mechanism of IFN resistance was examined in three long-term cell lines, SK-MEL-28, SK-MEL-3, and MM96, exhibiting significant variation in responsiveness to the antiproliferative and antiviral effects of type I IFNs. The JAK-STAT components involved in IFN signal transduction were analyzed in detail. After exposure to IFN, activation of the IFN type I receptor-linked tyrosine kinases, JAK-1 and TYK-2, was detected at similar levels in both IFN-sensitive and IFN-resistant cell types, indicating that IFN resistance did not result from a deficiency in signaling at the level of receptor-associated kinase activation. However, analysis of ISGF3 transcription factor components, STAT1, STAT2, and p48-ISGF3gamma, revealed that their expression and activation correlated with cellular IFN responsiveness. The analysis was extended to also include IFN-sensitive primary melanocytes, three additional IFN-resistant melanoma cell lines, and seven cell cultures recently established from melanoma patient biopsies. It was consistently observed that the most marked difference in ISGF3 was a lack of STAT1 in the resistant versus the sensitive cells. Transfection of the IFN-resistant MM96 cell line to express increased levels of STAT1 protein partially restored IFN responsiveness in an antiviral assay. We conclude that a defect in the level of STAT1 and possibly all three ISGF3 components in IFN-resistant human melanoma cells may be a general phenomenon responsible for reduced cellular responsiveness of melanomas to IFNs.

Partial phenotypic reversion of HeLa cells by long-term interferon-alpha treatment

Human papillomaviruses (HPV) are associated with malignant cervical neoplasia. Several HPV-related diseases have been shown to be sensitive to interferon (IFN) treatment. HeLa cells contain and express the HPV type 18 genome and were used as a model for the evaluation of the viral expression regulation and the effect on the malignant phenotype during IFN treatment. Cells were treated continuously with 200 IU/ml IFN-alpha 2b or natural leukocyte INF-alpha for six passages (42 days). Some IFN-induced changes were observed: decrease of HPV-18 mRNA expression, changes of cell morphology, and reduction of clonogenicity in soft agar. Tumorigenicity in nude mice was not modified. Other targets of the IFN system were analyzed, and an increase of the 2',5'-oligoadenylate synthetase mRNA level and a down-regulation of type I IFN receptor were found. These results demonstrate that long-term IFN-alpha treatment induces a partial phenotypic reversion of HeLa cells to a more differentiated stage were down-regulation of HPV-18 expression could play a central role. It therefore confirms that the IFN-alpha treatment may be therapeutically useful in cervix cancer produced by HPV-18.

Cytokine combinations in immunotherapy for solid tumors: a review

The use of cytokines alone or in combination with other cytokines or cytotoxic drugs has had a profound effect upon widely metastatic disease in many cases. However, despite the encouraging results in early trials, there is much room for improvement. Few responses to these combinations are complete, and toxicity has in some cases been quite severe. Changes in dose, route, or schedule of administration of the drugs, or the development of cytokine analogs may lead to more efficacious and less toxic regimens. In addition, new cytokines such as interleukin(IL)-7 and IL-12 are currently under investigation for potential use in future immunotherapy trials. These prospects and the use of cytokine combinations are promising advances in the treatment of human cancer.

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

We assessed the antiproliferative effect of human recombinant interferon -alpha (IFN-alpha) or -beta in combination with 5-fluorouracil (5-FU), cisplatin, or cis- or trans-retinoic acid on two human nonsmall cell lung carcinoma cell lines (SK-LU-1 and SK-MES-1) and on one human small cell lung carcinoma cell line (NCI-H69). Results were obtained by direct cell count and/or by the clonigenic assay. The three cell lines differed in their sensitivities to the antiproliferative effects of the different agents. However, both NSCLC cell lines were more responsive to IFN-beta than to IFN-alpha. The SK-MES cell line was more resistant to both IFNs than the SK-LU-1. The NCI-H69 cells were resistant to all the drugs tested, except trans-retinoic acid. The dose and time of exposure were found to be important factors in the case of IFNs and cytotoxic agents, with lower surviving fractions obtained with the higher doses and longer exposures. This finding, however, did not hold true for the retinoic acids, which showed no antiproliferative effect. Within the sensitivity of our system, we did not identify any synergistic interaction in any of the cell lines with IFN-alpha or IFN-beta and 5-FU or cisplatin. A slight synergistic interaction was observed with IFN and cis- or trans-retinoic acid in the SK-LU-1 cell line which was not thought to be clinically significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical and biologic effects of combination therapy with gamma-interferon and tumor necrosis factor

Tumor necrosis factor (TNF) and gamma-interferon (gamma-IFN) are cytokines with synergistic biologic and antiproliferative effects in vitro and in mouse models. The biologic effects of the combination of TNF and gamma-IFN, however, have not been studied well in humans. A Phase I trial was conducted of TNF and gamma-IFN therapy in 24 patients with advanced malignancies to determine the tolerability of the combination and the biologic effects of TNF and gamma-IFN in vivo. Both TNF and gamma-IFN were administered as 30-minute intravenous infusions three times per week. Doses of TNF ranged from 25 to 100 micrograms/m2; all patients received 100 micrograms/m2 of gamma-IFN. Dose-limiting toxicity consisted primarily of orthostatic hypotension and constitutional symptoms. The maximum tolerated dose level (MTDL) of 50 micrograms/m2 of TNF and 100 micrograms/m2 of IFN-gamma was less than the maximum tolerated dose (MTD) observed in previous Phase I trials of gamma-IFN and TNF alone. Biologic responses were studied in seven patients treated at the MTDL. Serum interleukin-2 receptor levels and neopterin secretion were enhanced significantly 24 hours after therapy (P = 0.002); enhancement of monocyte Fc receptor levels had borderline statistical significance (P = 0.07). With the exception of the mean fluorescent intensity on monocytes positive for histocompatibility antigen HLA-DR (P = 0.03), HLA Class I and II cell surface protein expression was not increased. The combination significantly enhanced indoleamine dioxygenase activity and serum beta 2-microglobulin expression (P less than 0.04) but not 2',5'-oligoadenylate synthetase activity, bactericidal function, or chemiluminescence. These results were compared retrospectively with those observed in previous Phase I trials of gamma-IFN and TNF alone. The combination of TNF and gamma-IFN significantly increased urinary kynurenine levels more than either TNF alone or gamma-IFN alone. Given the limitations inherent in any retrospective analysis, however, the enhancement in the other biologic parameters measured at the MTDL during this trial did not differ significantly from the changes observed at the MTD of either TNF or gamma-IFN alone. It was concluded that the combination of TNF and gamma-IFN, when administered at the MTDL of the combination, does not offer any enhancement in biologic responses over either agent alone.

Therapeutic use of cytokines in dermatology

Cytokines are glycoproteins produced by many different cells. Via binding to specific receptors on target cells they regulate the activation, differentiation, and proliferation of immune and nonimmune cells. After injury keratinocytes synthesize and release cytokines such as interleukins, colony stimulating factors, and growth factors. In addition, a network of interacting cytokines appears to be crucial to maintain proper balance. Dysregulation may contribute to certain diseases, particularly those of infectious and autoimmune origin. Therefore many of these mediators appear to be promising candidates to treat infectious and malignant diseases. This article briefly discusses the most important cytokines. Newly developed regimens with cytokines to treat cutaneous disorders will be reviewed.

Role of interferons in the therapy of melanoma

A range of potent immunoregulatory molecules termed cytokines has become available for the therapy of human melanoma. Among the cytokines, the interferons (IFN) have been examined in great depth for the therapy of melanoma. IFN are able to modulate host effector cell function, including the tumor cytolytic function of lymphocytes and monocytes. IFN also have the capacity to regulate the distribution of circulating immunoregulatory (T) lymphocytes and the expression of tumor cell surface antigens, as well as class I and II products of the major histocompatibility locus. These activities of the IFN have led to their early application for treatment of human melanoma. The empirical evidence that IFN alpha exerts clinically significant anti-tumor effects against melanoma is reviewed, and evolving status of adjuvant trials of IFN alpha and gamma is noted. New indirect host-mediated anti-tumor activities that may potentially be manifest by IFN have yet to be fully harnessed. The opportunity to obtain meaningful anti-tumor activity in advanced disease or adjuvant settings, at dose ranges below those which are toxic (conventional maximal tolerable), are at hand. The U.S. cooperative groups [Eastern Cooperative Oncology Group (ECOG), Cancer and Leukemia Group B (CALGB), and South West Oncology Group (SWOG)] are studying IFN gamma in pursuit of this goal in advanced and adjuvant settings for melanoma and other tumors. The determination of the clinical role of IFN as biologic response modifiers demands equal commitment to the clinical assessment of immunobiologic mechanisms and anti-tumor effects. The immunologic assessment of IFN and a number of other cytokines is a major focus of the Pittsburgh Cancer Institute. Regional delivery of cytokines such as interleukin-2 (IL-2) may be the most appropriate and least toxic approach, given their half-life. Regional therapy by the intralesional route has yielded enhanced activity for a range of biologics, including bacillus Calmette-Guerin (BCG), IL-2, and tumor necrosis factor (TNF). Intralymphatic therapy with methanol extraction residue of BCG (MER-BCG) has been tested, and trials are now in progress with IL-2 to assess the optimal dosage by this route. It is likely that the optimal role of IFN and other cytokines will be found in combination with one another, and with different biologic modalities such as monoclonal antibodies and vaccines, to allow expansion and heightened activity of the desired effector cell populations in the host. Enhanced host toxicities, as well as anti-tumor effects, may require that special attention be devoted to optimal sequence of administration to enhance the therapeutic index.

A direct comparison of biological response modulation and clinical side effects by interferon-beta ser, interferon-gamma, or the combination of interferons beta ser and gamma in humans

To directly compare clinical side effects and biological response modification, IFN-beta ser, IFN-gamma, or the combination of IFN-beta ser plus IFN-gamma was administered to 21 cancer patients. Each IFN or the combination was given intravenously on days 1, 8, and 15 in varied order. Each IFN and the combination resulted in significant (P less than 0.05) modulation of IFN-induced proteins. IFN-beta ser was more effective than IFN-gamma in enhancing 2-5A synthetase activity (P = 0.001). IFN-gamma was more effective than IFN-beta ser in enhancing serum beta 2 microglobulin expression (P = 0.05) and indoleamine dioxygenase activity, as assessed by decreased serum tryptophan (P = 0.03). The combination enhanced tryptophan catabolism more effectively than IFN-beta ser in a dose-dependent manner (P less than 0.03). IFN-beta ser/IFN-gamma did not potentiate natural killer cells or antibody-dependent cellular toxicity (ADCC). IFN-beta ser/IFN-gamma enhanced monocyte guanylate cyclase activity, as assessed by serum neopterin, more effectively than IFN-gamma alone (P = 0.005). Both IFNs and the combination resulted in increases in HLA class II expression on monocytes. However, no significant difference in the level of induction of HLA DQ and HLA DR expression between IFN-beta ser/IFN-gamma and either IFN-beta ser or IFN-gamma was noted. Although frequency and servity of side effects of IFN-beta ser, IFN-gamma, or the combination were dose related, induction of induced proteins (with exception of influences on tryptophan catabolism) were not a function of dose administered over the 10-fold range. Continued treatment with the combination intravenously three times a week for 4 wk sustained but did not further potentiate, most of the changes in interferon-induced proteins. Thus, IFN-beta ser and IFN-gamma each resulted in effective and essentially equivalent patterns of induction of induced proteins. When combined, however, these IFNs did not result in potentiation of biological response modification in vivo.

Growth inhibitory effects of interferon-beta but not interferon-alpha on human glioma cells: correlation of receptor binding, 2',5'-oligoadenylate synthetase and protein kinase activity

The antiproliferative effects of human recombinant interferon-alpha (rIFN-alpha A) and interferon-beta (rIFN-beta ser) were assessed in vitro against seven human glioma cell lines. Further analysis of one of these lines (EFC-2) in response to rIFN-alpha A demonstrated a minimum growth inhibition by day 6 of treatment, whereas a 50% inhibition of cell growth was observed with a dose of 50 U/ml of IFN-beta ser. No significant growth inhibition was seen by rIFN-alpha A at doses up to 500 U/ml. Addition of rIFN-alpha A to rIFN-beta ser-treated EFC-2 cells neither suppressed nor augmented the antiproliferative response to IFN-beta ser. The binding of 125I-labeled rIFN-alpha A or 125I-labeled rIFN-beta ser to EFC-2 cells was inhibited competitively by increasing concentrations of either unlabeled rIFN-alpha A or rIFN-beta ser. This suggests that the cellular receptors for both rIFN-alpha A and rIFN-beta ser appear to be intact and appear to bind both agents equally. Furthermore, incubation of EFC-2 cells for 72 h with either rIFN-alpha A or rIFN-beta ser resulted in an increase in 2',5'-oligoadenylate (2-5A) synthetase activity 5-fold with rIFN-alpha A and 50-fold with rIFN-beta ser. Similarly, the 68-kD IFN-induced protein kinase was induced substantially with rIFN-beta ser but only slightly induced with rIFN-alpha A treatment. These results suggest that EFC-2 human glioma cells demonstrate a differential sensitivity in terms of growth inhibition to rIFN-beta ser and to rIFN-alpha A which appears to correlate with a differential induction of both intracellular 2-5A synthetase and protein kinase activity. These results cannot be explained solely on the basis of surface receptor binding of rIFN-alpha A and rIFN-beta ser. These data do suggest that, for human glioma cells in culture, type I IFN receptors may display a subtle architectural variation that allows equivalent binding of both IFN-alpha and IFN-beta ser, but allows an enhanced signal transduction and biological effect only after binding a specific IFN subtype.

Interferons in dermatology

Interferons are a large family of proteins and glycoproteins, naturally occurring or artificially produced by recombinant biotechnology. Their antiviral, antiproliferative, antitumoral, and immunomodulatory activities are induced by alterations in cell metabolism after binding to specific membrane receptors. Interferons have been used for the treatment of viral papillomas (e.g., verruca vulgaris and condyloma acuminatum), human immunodeficiency virus (HIV)-associated Kaposi's sarcoma and cutaneous tumors (e.g., melanoma, cutaneous T cell lymphoma, and basal cell carcinoma), and inflammatory dermatoses (e.g., Behçet's syndrome and psoriatic arthropathy). Clinical trials have been performed worldwide with various regimens and have not always led to conclusive results. In our experience long-term therapy with high doses of subcutaneously injected, recombinant interferon-alpha-2a in patients with HIV-associated Kaposi's sarcoma induces a remission or stabilization of the disease. In malignant melanoma a low response rate is obtained in metastatic disease with the use of interferon as a single therapeutic agent. Combined with other antitumor agents, however, interferon seems to be a useful drug. Excellent control of Behçet's disease has been obtained, and the treatment of condylomata acuminata has been effective.

Phase II trial of a combination of interferon-beta ser and interferon-gamma in patients with advanced malignant melanoma

Based upon the in vitro synergistic activity of interferon-beta (IFN-beta) and interferon-gamma (IFN-gamma) observed in melanoma cells, we initiated a Phase II trial using the combination to determine the clinical antitumor efficacy in patients with advanced disease. Fifteen patients with metastatic malignant melanoma were given 2,000 micrograms of recombinant IFN-gamma (rIFN-gamma) (Biogen) intravenously (i.v.) over 10 min, followed by a 10 min i.v. injection of 30 million units of recombinant IFN-beta (rIFN-beta ser) (Triton) 3 x/week. Six patients had skin, soft tissue, nodal, or subcutaneous metastases, 6 had visceral disease only, and 3 had both. Seven patients had received prior treatment, including chemotherapy (6), radiotherapy (3), and/or immunotherapy (3). Side effects included typical IFN constitutional symptoms such as anorexia, fatigue, nausea, and myalgias, but were not dose limiting. The mean drop in the white blood cell count (WBC) following 1 month of therapy, compared to baseline, was 3.3 x 10(3)/mm2 (p = 0.002); the mean increase in SGOT was 24.1 U/l (p less than 0.001). One patient had a dose reduction for Grade III anorexia and fatigue which did not resolve with repeated treatment. One patient with liver metastases had radiographical and clinical stabilization of his disease for 1 year. No responses were seen. The median time to progression was 6 weeks. Two patients' tumors were evaluable in the human tumor colony forming assay (HTCFA) and were markedly sensitive to the antiproliferative effects of IFN combinations. Both patients, however, failed to respond clinically.(ABSTRACT TRUNCATED AT 250 WORDS)