Antiproliferative effects of natural interferon beta alone and in combination with natural interferon gamma on human breast carcinomas in nude mice

A functional in vitro model of heterotypic interactions reveals a role for interferon-positive carcinoma associated fibroblasts in breast cancer

BACKGROUND

Cancer-associated fibroblasts (CAFs) play an important role in breast cancer pathogenesis by paracrine regulation of breast cancer cell biology. Several in vitro and mouse models have characterized the role of cell contact and cytokine molecules mediating this relationship, although few reports have used human CAFs from breast tumors.

METHODS

Primary breast CAF cultures were established and gene expression profiles analysed in order to guide subsequent co-culture models. We used a combination of colorimetric proliferation assays and gene expression profiling to determine the effect of CAFs on the MCF-7 breast cancer cell in an indirect co-culture system.

RESULTS

Using gene expression profiling, we found that a subgroup of breast CAFs are positive for a type one interferon response, confirming previous reports of an activated type one interferon response in whole tumor datasets. Interferon positive breast cancer patients show a poor prognostic outcome in an independent microarray dataset. In addition, CAFs positive for the type one interferon response promoted the growth of the MCF-7 breast cancer cell line in an indirect co-culture model. The addition of a neutralizing antibody against the ligand mediating the type one response in fibroblasts, interferon-β, reverted this co-culture phenotype. CAFs not expressing the interferon response genes also promoted the growth of the MCF-7 breast cancer cell line but this phenotype was independent of the type one fibroblast interferon ligand.

CONCLUSIONS

Primary breast CAFs show inter-patient molecular heterogeneity as evidenced by interferon response gene elements activated in a subgroup of CAFs, which result in paracrine pro-proliferative effects in a breast cancer cell line co-culture model.

Mullerian inhibiting substance promotes interferon gamma-induced gene expression and apoptosis in breast cancer cells

This report demonstrates that in addition to interferons and cytokines, members of the TGF beta superfamily such as Mullerian inhibiting substance (MIS) and activin A also regulate IRF-1 expression. MIS induced IRF-1 expression in the mammary glands of mice in vivo and in breast cancer cells in vitro and stimulation of IRF-1 by MIS was dependent on activation of the NF kappa B pathway. In the rat mammary gland, IRF-1 expression gradually decreased during pregnancy and lactation but increased at involution. In breast cancer, the IRF-1 protein was absent in 13% of tumors tested compared with matched normal glands. Consistent with its growth suppressive activity, expression of IRF-1 in breast cancer cells induced apoptosis. Treatment of breast cancer cells with MIS and interferon gamma (IFN-gamma) co-stimulated IRF-1 and CEACAM1 expression and synergistic induction of CEACAM1 by a combination of MIS and IFN-gamma was impaired by antisense IRF-1 expression. Furthermore, a combination of IFN-gamma and MIS inhibited the growth of breast cancer cells to a greater extent than either one alone. Both reagents alone significantly decreased the fraction of cells in the S-phase of the cell cycle, an effect not enhanced when they were used in combination. However, MIS promoted IFN-gamma-induced apoptosis demonstrating a functional interaction between these two classes of signaling molecules in regulation of breast cancer cell growth.

Specific immunotherapy against occult cancer metastases

We investigated the efficacy of a preparation containing High Five (H5) insect cells infected with recombinant baculovirus encoding the murine interferon-beta gene (H5BVIFN-beta) against established primary tumors and occult lung metastases. Injection of live or lyophilized H5BVIFN-beta into established subcutaneous tumors of the highly metastatic murine UV-2237m fibrosarcoma or K-1735M2 melanoma in syngeneic mice eradicated both primary tumors and preexisting lung metastases. The therapeutic effects of H5BVIFN-beta were not observed in nude mice and were diminished in syngeneic mice depleted of CD4(+) and CD8(+) T cells. Immunohistochemical staining showed that tumors injected with H5BVIFN-beta were densely infiltrated by CD4(+) and CD8(+) T cells in mice with normal CD4/CD8 complement. These data demonstrate that, unlike most immunologic approaches in which prophylaxis can be achieved but eradication of established tumor is rare, lyophilized preparations of H5BVIFN-beta can serve as a novel immunotherapy against both primary tumors and their occult metastases.

Adenovirus-mediated interferon-beta gene therapy suppresses growth and metastasis of human prostate cancer in nude mice

The purpose of this study was to determine the effects of interferon-beta (IFN-beta) gene transfer on the growth of PC3MM2 human prostate cancer cells in nude mice. Intralesional delivery of an adenoviral vector encoding murine IFN-beta (AdIFN-beta), but not a vector encoding bacterial beta-galactosidase (AdLacZ), suppressed PC3MM2 tumors in a dose-dependent manner. At the highest dose (2x10(9) plaque-forming units, PFU), a single injection of AdIFN-beta (but not AdLacZ) suppressed orthotopic PC3MM2 tumors and development of metastasis by 80%, and eradicated the tumors in 20% of mice. Immunohistochemical staining showed that AdIFN-beta-treated tumors contained fewer microvessels, fewer proliferating cells, and more apoptotic cells than did the control tumors. Compared with controls, tumors injected with AdIFN-beta expressed higher levels of IFN-beta and inducible nitric oxide synthase (iNOS) and lower levels of basic fibroblast growth factor (bFGF) and transforming growth factor beta1 (TGF-beta1). In vitro analysis indicated that expression of bFGF and TGF-beta1 in PC3MM2 cells could be suppressed by the nitric oxide donor sodium nitroprusside. These data suggest that intratumoral delivery of the IFN-beta gene with adenoviral vectors could be an effective therapy for prostate cancer and that tumor suppression by AdIFN-beta correlated with up-regulation of iNOS and down-regulation of angiogenesis.

Inhibition of hormone and growth factor responsive and resistant human breast cancer cells by CeReS-18, a cell regulatory sialoglycopeptide

We have previously documented that CeReS-18, a cell regulatory sialoglycopeptide, inhibits the cellular proliferation of normal and transformed cell types from a diverse range of species. Most cell types studies exhibit a similar sensitivity to the reversible but growth inhibitory effects of CeReS-18 at 7 x 10(8) M concentration, while at higher concentrations CeReS-18 can elicit cytotoxicity. The present study was conducted to examine the effect of CeReS-18 on the proliferation of human mammary epithelial carcinoma cells. MCF-7 cells, which are estrogen receptor positive (ER+), and BT-20 cells, which are estrogen receptor negative (ER+), were utilized. Both cell lines show equal sensitivity to growth inhibition elicited by CeReS-18. Complete cessation of cell cycling was achieved with 7 x 10(-8) M CeReS-18, and the arrest was shown to be completely reversible. Flow cytometric analysis, performed on CeReS-18 treated cells from both cell types, revealed that the majority of these cells were arrested in the G1 phase of the cell cycle. When cells were treated simultaneously with inhibitor and stimulatory concentrations of mitogens such as epidermal growth factor (EGF), basic fibroblast growth factor (b-FGF), estrogen, insulin-like growth factors I and II (IGFI and IGFII), no alteration of the inhibitory activity of CeReS-18 was observed. CeReS-18 clearly abrogated the mitogenic activity that these growth factors elicited with human mammary carcinoma cells.

Cytokines in animal models of cancer

Cytokines are a complex family of mediators that play a wide role in development, immunity, inflammation and tissue repair. Their use in therapy is still in its infancy and animal models have a key role to play in optimizing doses and schedules. Whilst xenogeneic and syngeneic transplantable systems have traditionally been used to look at the effects of cytokines in tumour models, oncogene transgenic mice prone to develop cancer, may now have a role to play. Moreover, gene therapy has allowed the investigation of ectopically expressed high and continuous levels of cytokines. We will attempt to review the literature on the effect of cytokines and their combinations in these models of cancer.

Regression of skin recurrences of breast carcinomas treated with intralesional injections of natural interferons alpha and gamma

Two groups of patients with disseminated breast carcinomas who had failed radiotherapy, chemotherapy, and hormonotherapy were treated with natural interferon alpha (nIFN-alpha) alone or in combination with nIFN-gamma delivered in cycles of 10-12 intralesional (i.l.) injections to recurrent and metastatic lesions. In group, I, 16 skin lesions in 12 patients received nIFN-alpha alone resulting in 7 complete regressions verified histologically (CR), 7 partial regressions (PR), and no regressions (NR) in 2. Group II included 4 patients in whom 7 cutaneous recurrences were treated with nIFN-alpha/nIFN-gamma (5 CR, 2 PR), 2 were injected with nIFN-alpha alone (1 CR, 1 PR), and 1 received nIFN-gamma alone (PR). Two additional patients in group II were given i.l. injections of nIFN-alpha/nIFN-gamma to lymph node metastases (1 CR, 1 PR). Clinical toxicity was experienced by 5 of 12 patients in group I and by all the patients in group II and was controlled in most instances by antipyretics. Systemic antitumor effects were not appreciable clinically. Nevertheless, noninjected lesions exposed only to systemic levels of IFNs, when studied immunohistochemically, displayed an immunological response similar to that of IFN-injected lesions, although less intense. Therefore, IFNs can be useful in controlling locoregional recurrences of breast cancer even in patients who are not responding to other forms of therapy. Furthermore, in addition to the local antitumor actions, they appear to be capable of eliciting systemic immunological effects.

Human recombinant interferon-beta SER and tamoxifen: growth suppressive effects for the human breast carcinoma MCF-7 grown in the athymic mouse

Tamoxifen is the endocrine treatment of choice for breast cancer. However, resistance to therapy and patient relapse inevitably occurs. In future treatment schedules, interferons could be administered with tamoxifen, in an attempt to prevent disease recurrence. Human recombinant interferon-beta SER (rIFN-beta SER) inhibited the growth in vitro of the estrogen receptor (ER) positive breast cancer cell line MCF-7 and the ER negative breast cancer cell line MDA-MB-231. This inhibitory effect was achieved at doses of 50 U/ml and above. The growth of MCF-7 tumors in estradiol-stimulated athymic mice was greatly inhibited by high dose rIFN-beta SER treatment (10(6)U/day). In spite of the impressive antitumor effects upon MCF-7 tumors, rIFN-beta SER had no effect upon ER levels within the tumors at either the RNA or protein level, as measured by Northern blotting and ER-EIA respectively. High dose rIFN-beta SER (10(6)U/day) did result in some inhibition in the growth in vivo of the tamoxifen-stimulated MCF-7 variant MCF-7 TAM, although not to the same extent as was observed with the estradiol-stimulated MCF-7 tumors. rIFN-beta SER was also administered to animals bearing MCF-7 tumors and treated with estradiol and tamoxifen. In the animals undergoing high dose therapy (10(6)U/day), tumor growth was completely suppressed. Furthermore, tumor growth continued to be suppressed in those animals in which the rIFN-beta SER therapy was halted and the tamoxifen capsule removed. No tumors were observed in spite of the environment of estradiol stimulation. Thus, the combination of interferon and tamoxifen was totally growth suppressive for MCF-7 xenografts in nude mice.

Effects of interferons and other cytokines on tumors in animals: a review

The term cytokine describes a group of protein cell regulators involved in the control of cell growth and differentiation in embryogenesis, immunity and inflammation. They are of low molecular weight, are produced locally, and act in an autocrine or paracrine manner. In the past decade their use as cancer therapy has become a reality. Thirty years ago mice were treated with the antiviral protein interferon (IFN) which not only produced a reduction in the incidence of virus-induced tumors but also slowed the development of transplantable tumors. This was one of the first indications that cytokines can be negative regulators of cell growth. Here we outline current knowledge of the actions of IFNs and other cytokines in animal models, and draw parallels with clinical trials to illustrate the invaluable nature of this preclinical and mechanistic work.