Steroid receptor enhancement by natural interferon-beta in advanced breast cancer

Molecular targets and therapeutic strategies for triple-negative breast cancer

Triple-negative breast cancer (TNBC) is known for its heterogeneous complexity and is often difficult to treat. TNBC lacks the expression of major hormonal receptors like estrogen receptor, progesterone receptor, and human epidermal growth factor receptor-2 and is further subdivided into androgen receptor (AR) positive and AR negative. In contrast, AR negative is also known as quadruple-negative breast cancer (QNBC). Compared to AR-positive TNBC, QNBC has a great scarcity of prognostic biomarkers and therapeutic targets. QNBC shows excessive cellular growth and proliferation of tumor cells due to increased expression of growth factors like EGF and various surface proteins. This study briefly reviews the limited data available as protein biomarkers that can be used as molecular targets in treating TNBC as well as QNBC. Targeted therapy and immune checkpoint inhibitors have recently changed cancer treatment. Many studies in medicinal chemistry continue to focus on the synthesis of novel compounds to discover new antiproliferative medicines capable of treating TNBC despite the abundance of treatments currently on the market. Drug repurposing is one of the therapeutic methods for TNBC that has been examined. Moreover, some additional micronutrients, nutraceuticals, and functional foods may be able to lower cancer risk or slow the spread of malignant diseases that have already been diagnosed with cancer. Finally, nanomedicines, or applications of nanotechnology in medicine, introduce nanoparticles with variable chemistry and architecture for the treatment of cancer. This review emphasizes the most recent research on nutraceuticals, medication repositioning, and novel therapeutic strategies for the treatment of TNBC.

Interferon Signaling in Estrogen Receptor-positive Breast Cancer: A Revitalized Topic

Cancer immunology is the most rapidly expanding field in cancer research, with the importance of immunity in cancer pathogenesis now well accepted including in the endocrine-related cancers. The immune system plays an essential role in the development of ductal and luminal epithelial differentiation in the mammary gland. Originally identified as evolutionarily conserved antipathogen cytokines, interferons (IFNs) have shown important immune-modulatory and antineoplastic properties when administered to patients with various types of cancer, including breast cancer. Recent studies have drawn attention to the role of tumor- and stromal-infiltrating lymphocytes in dictating therapy response and outcome of breast cancer patients, which, however, is highly dependent on the breast cancer subtype. The emerging role of tumor cell-inherent IFN signaling in the subtype-defined tumor microenvironment could influence therapy response with protumor activities in breast cancer. Here we review evidence with new insights into tumor cell-intrinsic and tumor microenvironment-derived IFN signaling, and the crosstalk of IFN signaling with key signaling pathways in estrogen receptor-positive (ER+) breast cancer. We also discuss clinical implications and opportunities exploiting IFN signaling to treat advanced ER+ breast cancer.

Interferons: role in cancer therapy

Interferons (IFNs) are a group of signaling cytokines, secreted by host cells to induce protection against various disorders. IFNs can directly impact on tumor cells or indirectly induce the immune system to protect host cells. The expression levels of IFNs and its functions of are excellently modulated in a way to protect host cells from probable toxicities caused by extreme responses. The efficacy of anticancer therapies is correlated to IFNs signaling. Although IFN signaling is involved in induction of antitumor responses, chronic stimulation of the IFN signaling pathway can induce resistance to various antineoplasm therapies. Hence, IFNs are expressed by both cancer and immune cells, and modulate their biological function. Understanding this mechanism of action might be a key target of combination therapies.

Antitumour actions of interferons: implications for cancer therapy

The interferons (IFNs) are a family of cytokines that protect against disease by direct effects on target cells and by activating immune responses. The production and actions of IFNs are finely tuned to achieve maximal protection and avoid the potential toxicity associated with excessive responses. IFNs are back in the spotlight owing to mounting evidence that is reshaping how we can exploit this pathway therapeutically. As IFNs can be produced by, and act on, both tumour cells and immune cells, understanding this reciprocal interaction will enable the development of improved single-agent or combination therapies that exploit IFN pathways and new 'omics'-based biomarkers to indicate responsive patients.

Immune manipulation of advanced breast cancer: an interpretative model of the relationship between immune system and tumor cell biology

This review summarizes some recent clinical immunological approaches with cytokines and/or antibodies for therapy of advanced breast cancer. It considers the recent advances in genetics and molecular tumor biology related to impaired immunosurveillance involving cytokines and growth factors to explain clinical results. Evasion of the host immune attack might be induced by the following groups of mechanisms: (a) tumor dependent (genomic instability, HLA class I antigen abnormalities, upregulation of fetal type nonclassical HLA class I molecules, epitope immunodominance, apoptosis inhibition by defective death receptor signaling, apoptosis of activated T cells, tumor cannibalism and constitutive activation of signal transducer, and activator of transcription-3 (Stat 3) and nuclear factor-kappaB (NF-kappaB) signaling); (b) host dependent (CD4+CD25+ regulatory T cells (T reg), CD4+ T cells anergy, Th2 antitumor immunity diversion and myeloid suppressor cells); (c) tumor and host dependent (lack of co-stimulation molecules, immunosuppressive cytokines (vascular endothelial growth factor (VEGF), interleukin (IL)-10, prostaglandin (PG)E2, transforming growth factor (TGF)-beta)). Cytokines and growth factors are involved in virtually all three types of mechanisms. These mechanisms are integrated with the current knowledge of tumor growth and inhibited apoptosis primarily mediated by cytokines and growth factors to propose an interpretation of the relationships among tumor cells, tumor stroma, and tumor-infiltrating lymphocytes. Tumor growth, defective immunorecognition and immunosuppression are the three principal effects considered responsible for immune evasion.

Cytokines in breast cancer

In recent decades many advances have occurred in the understanding of the role of cytokines in breast cancer. New signalling pathways of interleukin (IL)-1 family, IL-6, IL-11, IL-18, interferons (IFNs) and interferon regulatory factors 1 (IRF-1) and 2 (IRF-2) have been found within tumour microenvironments and in metastatic sites. Some cytokines (IL-1, IL-6, IL-11, TGFbeta) stimulate while others (IL-12, IL-18, IFNs) inhibit breast cancer proliferation and/or invasion. Similarly, high circulating levels of some cytokines seem to be favourable (soluble IL-2R) while others are unfavourable (IL-1beta, IL-6, IL-8, IL-10, IL-18, gp130) prognostic indicators. So far IL-2, IFNalpha, IFNbeta and occasionally IFNgamma, IL-6, IL-12 have been the cytokines used for anti tumour treatment of advanced breast cancer either to induce or increase hormone sensitivity and/or to stimulate cellular immunity. Disappointing results occurred in most trials; however, two long-term pilot studies suggest that IL-2 and IFNbeta, when used appropriately can have a positive effect on clinical benefit and overall survival of patients with minimal residual disease after chemotherapy or with disseminated disease controlled by conventional endocrine therapy.

Beta-interferon and interleukin-2 prolong more than three times the survival of 26 consecutive endocrine dependent breast cancer patients with distant metastases: an exploratory trial

Distant metastases from breast cancer are incurable. In endocrine-responsive patients antiestrogens are commonly administered as first and second line therapy. Regrettably, tumor growth becomes resistant to this relatively innocuous therapy. Beta-interferon was unsuccessfully added to tamoxifen to induce estrogen receptor enhancement. In mice, interleukin-2 added to tamoxifen increased their mutual anti-tumor activities. Nevertheless, no effective clinical application has been developed. We started an exploratory clinical trial based on the association of these immunostimulating cytokines with antiestrogens for first line salvage therapy of hormone dependent breast cancer with distant metastases. Twenty-six consecutive breast cancer patients with distant metastases, 23 of which had metastases at multiple sites, were studied for responsiveness to treatment with first line salvage antiestrogen therapy, combined with beta-interferon and interleukin-2 immuno-therapy. Clinical response and survival were compared with that of 30 consecutive historical control patients treated with antiestrogen therapy alone. Controls showed, as expected, a median duration of response, a median survival time after treatment, and after diagnosis of distant metastases, of 16, 31 and 34 months, respectively. After a mean follow-up of 62+/-36 months (range 17-155), the interval times in the non-control patients were 61 (P<0.001), 101 (P<0.000001) and 106 (P<0.000001) months. Two long-term survivors appeared to be cured after 155 and 94 months from the time of diagnosis with multiple bone metastases. Nineteen of the patients treated with beta-interferon and interleukin-2 have survived. Hormone immuno-therapy was given in an outpatient setting and was very well tolerated. These data suggest that immuno-therapy plays an important role in endocrine-dependent metastatic breast cancer.

Minimal residual disease in metastatic breast cancer: treatment with IFN-beta, retinoids, and tamoxifen

The aim of this pilot study was to investigate if chemotherapy (CT) followed by the combination of interferon-beta (IFN-beta), retinoids, and tamoxifen could be effective in the treatment of metastatic breast cancer (MBC). Thirty-six patients with stage IV carcinoma of the breast were treated with six courses of cyclophosphamide, 5-fluorouracil, 4-epidoxorubicin, vincristine, and prednisone every 3 weeks (FECPV), followed by two courses of non-cross-resistant drugs, methotrexate, mitomycin C, and mitoxantrone (MMM). Treatment was continued, in responders, with low dose IFN-beta, retinyl palmitate, and tamoxifen until relapse of the disease occurred. Among 36 evaluable patients, 23 achieved a clinical response (64 %) (95 % confidence interval [c.i.] 46 %-79 %), 7 had stable disease (19%), and 6 (17%) progressed. Leukopenia occurred in 15 patients, thrombocytopenia in 6, and anemia in 11. Sixteen patients had nausea/vomiting, stomatitis was observed in 9, and diarrhea occurred in 3. Toxicity from maintenance therapy was mild and mainly hepatic. Median response duration was 31 months (range 5-107). Median overall survival was 32 months (9-108). Our study shows that this combined approach for the treatment of MBC is feasible, with an acceptable toxicity.

Interferon-beta can induce progesterone receptors in human endometrial adenocarcinoma

BACKGROUND

The induction of estrogen and progesterone receptors (ER and PGR) has been reported in breast and endometrial cancer cells exposed to human fibroblast interferon-beta (hIFN-beta). Clinical verification of this finding might provide the rationale for new therapeutic approaches. This study was designed to evaluate whether clinical treatment with high doses of hIFN-beta induced ER and PGR in patients with endometrial adenocarcinoma.

METHODS

Two biopsies were obtained, 1 before and 1 after hIFN-beta treatment (3 x 10(6) i.m. every other day for 3 weeks) from 36 patients with endometrial adenocarcinoma. ER and PGR were determined with standard procedures using radiolabeled ligands.

RESULTS

hIFN-beta treatment did not affect the proportion of ER-positive (i.e., >15 fmol/mg protein) or PGR-positive (i.e., >20 fmol/mg protein) cases. However, in patients with detectable ER and PGR at baseline, hIFN-beta raised the levels. Using a 35% difference before and after therapy as a cut-off, 72 and 79% of cases had increases in ER and PGR, respectively. The difference was highly significant for PGR.

CONCLUSIONS

In patients with endometrial adenocarcinoma with undetectable ER or PGR, hIFN-beta did not induce the expression of these receptors. When the receptors were present they were upregulated by hIFN-beta. Whether this increase in receptor levels, particularly PGR, has therapeutic applications remains to be established.

Oncogene expression is modulated by recombinant human interferon-beta in human breast-cancer cells

The effect of recombinant human interferon-beta on growth and oncoprotein expression was investigated in several human breast-cancer cell lines with different characteristics. All cell lines tested were sensitive to the antiproliferative action of the drug, regardless of their estrogen sensitivity. The maximal inhibition of cell proliferation was seen after 6 days of treatment. In estrogen-sensitive CG-5 and ZR-75-1 cells, but not in MDA-MB-453 estrogen-insensitive cells, a reduction in c-myc and c-erbB2 oncoproteins occurred after 48-72 hr and became more pronounced after 120-168 hr of treatment, suggesting that this down-regulation is not direct but is mediated by undefined molecular mechanisms. The time-course of the IFN-mediated decrease in oncoproteins seems to indicate that this event is not strictly related to the IFN-regulation of cell proliferation. The expression of c-erbB2 and c-myc was also analyzed, after recombinant human interferon-beta treatment, at the mRNA level in CG-5 cells. Surprisingly, no statistically significant variation of c-erbB2 or of c-myc mRNA was found either before or after 120-168 hr. Thus, we surmise that the observed reduction of oncoproteins may be due to post-transcriptional mechanisms.

Tamoxifen and interferon-beta for the treatment of metastatic breast cancer

It has been demonstrated, both in breast cancer cell lines and in metastatic breast cancer patients with cutaneous lesions that could be biopsied, that treatment with interferon beta (IFN-B) can increase expression of both estrogen (ER) and progesterone receptors (PgR). To evaluate the efficacy and toxicity of the combination of IFN and tamoxifen, 33 metastatic breast cancer patients were treated with the following regimen: IFN-B, 6.0 million units intramuscularly IU 3 times a week for two consecutive weeks followed by IFN-B 6.0 million IU im 3 times a week with concomitant tamoxifen 20 mg orally daily. Patients were pre and postmenopausal with median age of 60 years, median ECOG PS of 0, either ER positive or unknown, and had not received prior hormone therapy for metastatic disease. Overall objective response was observed in 9 (27%) patients. Complete response was observed in 2 cases and partial response in 7 patients. Median duration of response was 7 months (range 2-10). A higher response rate was observed in patients with predominantly soft tissue disease (38%) compared to patients with either dominant bone (18%) or visceral lesions (17%). Toxicity was mild and reversible: low grade fever in 30% of patients and flu-like symptoms in 9% of cases. It appears that IFN-B does not improve the efficacy of tamoxifen in an unselected population of metastatic breast cancer.

Potential uses of interferon alpha 2 as adjuvant therapy in cancer

BACKGROUND

The purpose of this study was to provide an overview of the potential uses of adjuvant interferon (IFN) therapy for resected solid tumors at high risk for postsurgical relapse.

METHODS

A MEDLINE search (1970-1994) of the English-language literature for original articles, reviews, and abstracts addressing IFN use in the adjuvant setting together with the authors' collective experience formed the basis for this review.

RESULTS

The use of adjuvant IFN-alpha has been studied most extensively in conjunction with the treatment of melanoma. Fewer data are available on IFN-alpha use for the treatment of other solid tumors. In melanoma, there is evidence from Intergroup trials (Eastern Cooperative Oncology Group and World Health Organization) that IFN-alpha 2a given for 1-3 years prolongs the interval to relapse and may have a survival benefit. Trials of adjuvant IFN, with and without chemotherapy, are ongoing in the treatment of renal cell carcinoma and colorectal adenocarcinoma. Its value in the treatment of osteosarcoma and high-grade astrocytoma is unknown.

CONCLUSIONS

The use of IFN in the adjuvant setting is an exciting area of medical and surgical oncology and has the potential to prolong the time to relapse and to increase survival of patients with melanoma. Its role in the adjuvant therapy of other solid tumors remains to be defined.

Interferon-beta, retinoids, and tamoxifen in the treatment of metastatic breast cancer: a phase II study

Based on the additive or synergistic antiproliferative effect of interferon and tamoxifen on breast cancer cell lines and on preclinical and clinical data on retinoids alone and in combination with antiestrogen or interferon, we designed a pilot phase II study to test the toxicity of simultaneous administration of interferon-beta (IFN-beta), retinoids (R), and tamoxifen (TAM) and the efficacy of this combination as salvage therapy in a group of patients with metastatic breast cancer (MBC). A total of 49 stage IV breast cancer patients, 11 pretreated with hormones, 26 with chemotherapy, and 12 with both, received 30 mg TAM and two dose levels of IFN-beta and retinyl palmitate. Among 49 evaluable patients, 27 achieved a clinical response (55%; 95% CI 41-69%), 10 had stable disease (20%), and in 12 (25%) the disease progressed. Toxicity with both dose levels was moderate and mainly hepatic. Median response duration, not statistically different in estrogen receptor-positive and negative patients, was 31.4 months (range 4.9-67). Median overall survival was 19.2 months (range 2-69). We have shown that long-term administration of TAM, IFN-beta, and retinyl palmitate is feasible with moderate toxicity. We have also demonstrated that this regimen is active in pretreated MBC patients and that responses are not influenced by receptor status.

Effect of recombinant human interferon-alpha/2b on epidermal-growth-factor-, estrogen- and progesterone-receptor expression in primary cervical cancer

The effects of a short period of in vivo systemic rh-IFN-alpha/2b treatment on epidermal-growth-factor(EGFR)-, estrogen(ER)- and progesterone(PR)-receptor content in 11 primary human cervical tumors was investigated by the radioreceptorial technique. EGFR levels were found to be significantly higher in cervical tumors after rh-IFN-alpha/2b treatment with respect to basal levels. In 2 cases, immunohistochemical and cytofluorimetric analysis showed that rh-IFN-alpha/2b treatment induces an increase in EGFR immunoreactivity and in the fraction of EGFR-positive cells. No difference in ER and PR levels in cervical tumors before and after rh-IFN-alpha/2b treatment was observed. Our results suggest that rh-IFN-alpha/2b up-regulates EGFR in primary human cervical tumors in vivo.