Effect of murine interferon alpha/beta on tumour-induced suppressor function

The Use of Registries to Improve Cancer Treatment: A National Database for Patients Treated with Interleukin-2 (IL-2)

Registries evaluating un-randomized patients have provided valuable information with respect to a therapy's utility, treatment practices, and evolution over time. While immunotherapy for cancer has been around for more than three decades, data collection in the form of a registry has not been undertaken. The authors believe that establishing a registry to study HD IL-2 immunotherapy, which has been the only systemic therapy producing long term unmaintained remissions for advanced kidney cancer and melanoma for over 20 years, will be an important resource in understanding the impact of immunotherapy with HD IL-2 in a rapidly changing therapeutic environment. Optimizing administration and improving selection of appropriate patients likely to benefit from HD IL-2 immunotherapy are two of many benefits to be derived from this endeavor.

Inducible nitric oxide synthase activity is essential for inhibition of prostatic tumor growth by interferon-beta gene therapy

We have previously reported that adenoviral vector-mediated interferon (IFN)-beta gene therapy inhibits orthotopic growth of human prostate cancer cells in nude mice. The purpose of this study was to determine efficacy and mechanisms of this therapy in immune-competent mice. TRAMP-C2Re3 mouse prostate cancer cells infected with 100 multiplicity of infection (MOI) of adenoviral vector encoding for mouse IFN-beta (AdmIFN-beta), but not AdE/1 (a control adenoviral vector), produced approximately 60 ng/10(5) cells/24 h of IFN-beta. The tumorigenicity of AdmIFN-beta-transduced cells was dramatically reduced in the prostates of C57BL/6 mice. A single intratumoral injection of 2 x 10(9) PFU (plaque-forming unit) of AdmIFN-beta inhibited tumor growth by 70% and prolonged survival of tumor-bearing mice. Intriguingly, this AdmIFN-beta therapy did not alter the growth of tumors in inducible nitric oxide synthase (iNOS)-null C57BL/6 mice. Immunohistochemical analysis revealed that treatment of tumors with AdmIFN-beta in wild-type C57BL/6 mice led to increased iNOS expression, decreased microvessel density, decreased cell proliferation, and increased apoptosis. Furthermore, quantitative reverse-transcriptional PCR analysis showed that AdmIFN-beta therapy, in C57BL/6 but not the iNOS-null counterparts, reduced levels of the mRNAs for angiopoietin, basic fibroblast growth factor, matrix metalloproteinase-9, transforming growth factor-beta1, vascular endothelial growth factor (VEGF)-A, and VEGF-B, as well as the antiapoptotic molecule endothelin-1. These data indicated that IFN-beta gene therapy could be effective alternative for the treatment of locally advanced prostate cancer and suggest an obligatory role of NO in IFN-beta antitumoral effects in vivo.

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.

Vitamin D3 treatment to diminish the levels of immune suppressive CD34+ cells increases the effectiveness of adoptive immunotherapy

Tumor growth can increase the number of immature bone marrow-derived CD34+ cells that exhibit natural suppressor (NS) activity toward T-cell function. Using a metastatic Lewis lung carcinoma (LLC-LN7) tumor model, these CD34+ NS cells were shown to be present within the s.c. primary tumor tissue, but their levels declined after treatment with the inducer of myeloid cell differentiation, vitamin D3. Therefore, studies determined whether vitamin D3 treatment to diminish the CD34+ NS cell levels in LLC-LN7-bearing mice would enhance (a) intratumoral immune reactivity and (b) the antitumor activity of adoptive therapy consisting of tumor-reactive lymph node cells. The results showed that vitamin D3 treatment alone increased the intratumoral CD8+ cell content and the activity of the intratumoral infiltrate, as detected by production of interferon-gamma and expression of the p55 IL-2 receptor. Although vitamin D3 treatment had no effect on the size of the primary tumor, it lessened the extent of tumor metastasis. Treating mice with the combination of vitamin D3 and adoptive immunotherapy significantly reduced metastasis in mice with established tumors, and reduced both metastasis and locoregional recurrence after surgical excision of the primary tumor. These studies demonstrate that vitamin D3 treatment increases intratumoral T-cell immune reactivity, and that coupling vitamin D3 treatment to diminish levels of CD34+ NS cells with adoptive immunotherapy enhances the effectiveness of the adoptively transferred tumor-reactive lymph node cells at limiting both metastasis and locoregional tumor recurrence.

Myeloid progenitor cells mediate immune suppression in patients with head and neck cancers

Patients with squamous cell carcinomas of the head and neck (HNSCC) have profound defects in their immune defenses. We have shown that among the mechanisms that contribute to this immune dysfunction are immune inhibitory CD34+ progenitor cells, whose levels become elevated in the peripheral blood and within the tumor tissue. One goal of our studies is to overcome the immune inhibitory activities of tumor-induced CD34+ progenitor cells by stimulating their differentiation into cells, such as dendritic or monocytic cells, that can stimulate immune reactivity to autologous cancer. Results of in vitro analyses with CD34+ suppressor cells of HNSCC patients and of in vivo studies in animal tumor models have shown the capacity of tumor-induced CD34+ cells to differentiate into cells that phenotypically resemble monocytic or dendritic cells. Whether these cells can differentiate into dendritic cells in HNSCC patients is currently being tested. Less clear is whether the pathway by which the tumor-induced CD34+ cells differentiate will result in cells having the full capacity to function as potent stimulators of immune reactivity to autologous tumor.

Failure of tumor-reactive lymph node cells to kill tumor in the presence of immune-suppressive CD34+ cells can be overcome with vitamin D3 treatment to diminish CD34+ cell levels

Growth of Lewis lung carcinoma (LLC-LN7) tumors results in an increase in CD34+ granulocyte-macrophage progenitor cells having natural suppressor (NS) activity. These CD34+ NS cells were capable of inhibiting the cytotoxic activity of tumor-reactive lymph node cells. In vivo studies showed that adoptive treatment of LLC-LN7 tumor-bearing mice with tumor-reactive lymph node cells plus IL-2 failed to reduce the development of metastases. Studies were conducted to determine if diminishing the levels of CD34+ NS cells would allow for improved anti-tumor effectiveness of the adoptively transferred cells. The suppressive activity of CD34+ cells toward the cytolytic activity of tumor-reactive lymph node cells could be blocked by in vitro culture of CD34+ cells with the differentiation-inducing hormone 1alpha,25-dihydroxyvitamin D3. Similarly, treatment of LLC-LN7-bearing mice with vitamin D3 alone diminished the levels of CD34+ NS cells within regional lymph nodes, spleens and tumors. This treatment resulted in an increased immune reactivity to autologous tumor, as shown by the production of IFN-gamma by lymph node cells in response to the presence of LLC-LN7 cells. The extent of tumor metastasis in mice receiving vitamin D3 treatment was also reduced. When tumor-reactive lymph node cells were adoptively transferred into these LLC-LN7-bearing mice that were receiving vitamin D3 treatment, there resulted a pronounced synergistic reduction in tumor metastasis. The results of this study show that treatment of tumor bearers with vitamin D3 to eliminate CD34+ NS cells improves the anti-tumor effectiveness of adoptively transferred tumor-reactive lymph node cells.

Vitamin D3 treatment of tumor bearers can stimulate immune competence and reduce tumor growth when treatment coincides with a heightened presence of natural suppressor cells

By secreting granulocyte-macrophage colony-stimulating factor (GM-CSF), Lewis lung carcinoma tumors induce immune suppressive granulocyte-macrophage progenitor cells. Treating mice having established tumors and high levels of suppressor activity with vitamin D3 eliminated suppressor activity, increased anti-tumor immunity, induced an immune stimulatory cell population, and reduced tumor growth. When instead, the vitamin D3 treatment was initiated earlier, when implanted tumors first became detectable and when natural suppressor activity was less prominent, the treatment had no effect. Thus, vitamin D3 treatment can stimulate the immune competence of tumor bearers when treatment is targeted to coincide with a heightened presence of GM-CSF-induced suppressor cells.