Prevention by delay: nonspecific immunity elicited by IL-12 hinders Her-2/neu mammary carcinogenesis in transgenic mice

As a natural consequence of the expression of the activated transforming rat Her-2/neu oncogene all mammary glands of female transgenic BALB/c (BALB-neuT) mice develop atypical epithelial hyperplasia which progresses to invasive carcinoma. A lobular carcinoma is palpable in all mammary glands of 33-week-old BALB-neuT mice. This progression is markedly delayed by systemic administration of IL-12. In a series of studies the best administration schedule, the lowest dose and the most effective administration time have been defined. The cellular and molecular mechanisms resulting in the delay of carcinogenesis have been established. By means of a series of downstream mediators IL-12 inhibits the angiogenic burst that goes along with the passage from preneoplastic to neoplastic and invasive lesions; it also recruits lymphoid cells in the mammary pad and activates their cytotoxicity towards neoplastic cells and newly formed vessels; and furthermore, it induces lymphoid cells to trigger antiangiogenic activities in neoplastic epithelial cells. Effective, low-dose and non-toxic IL-12 treatments may thus be envisaged as a possible option in the management of preneoplastic mammary lesions and in mammary cancer prevention.     

Genome-wide analysis of molecular changes in IL-12-induced control of mammary carcinoma via IFN-gamma-independent mechanisms

IL-12 is a major activator of tumor-killing NK cells and CTL. IFN-gamma mediates most of the well-known immunological activities of IL-12. In this study, we report IFN-gamma-independent activities induced by therapeutic application of rIL-12 in restricting tumor growth and metastasis in the 4T1 murine mammary carcinoma model. IFN-gamma-deficient mice carrying 4T1 tumor exhibit no gross defect in the number of tumor-infiltrating lymphocytes but have exaggerated angiogenesis in the tumor. Administration of IL-12 is able to constrict blood vessels in the tumor in the absence of IFN-gamma, and retains certain therapeutic efficacy even when applied late during tumor progression. IL-12 exposure in vivo does not irreversibly alter the immunogenicity of the tumor. Finally, global gene expression analysis of primary tumors reveals IL-12-induced molecular patterns and changes, implicating a number of novel genes potentially important for IFN-gamma-independent immune responses against the tumor, for IL-12-mediated antiproliferation, antimetastasis, and antiangiogenesis activities.     

Fas/Fas ligand pathway, apoptosis, and clonal anergy involved in systemic acetylcholine receptor T cell epitope tolerance

The cellular mechanisms of high dose systemic acetylcholine receptor (AChR) T cell epitope, alpha 146--162 peptide-induced tolerance in experimental myasthenia gravis were examined. CD4 cells are the prime target for alpha 146--162 peptide-induced tolerance. The expression of CD69, Fas, and B7.2 molecules on AChR-immune lymphocytes was enhanced within 4--12 h after tolerance induction. A high dose of alpha 146--162 peptide in IFA failed to suppress T cell proliferation and/or clinical myasthenia gravis in lpr and gld mice deficient in Fas and Fas ligand, respectively. A high dose of alpha 146--162 peptide in IFA in AChR-immunized mice induced apoptosis of BV6 cells. Further, reconstitution of IL-2 in vitro-recovered alpha 146--162 peptide tolerized T cell proliferation, IFN-gamma, and IL-10 production. The findings implicate the possible role of Fas-/Fas ligand-mediated apoptosis and the resulting clonal anergy as the mechanisms of high dose AChR alpha 146--162 peptide-induced tolerance on CD4 cells.     

Antiangiogenic and antitumor activities of IL-27

IL-27 is a novel IL-6/IL-12 family cytokine playing an important role in the early regulation of Th1 responses. We have recently demonstrated that IL-27 has potent antitumor activity, which is mainly mediated through CD8(+) T cells, against highly immunogenic murine colon carcinoma. In this study, we further evaluated the antitumor and antiangiogenic activities of IL-27, using poorly immunogenic murine melanoma B16F10 tumors, which were engineered to overexpress single-chain IL-27 (B16F10 + IL-27). B16F10 + IL-27 cells exerted antitumor activity against not only s.c. tumor but also experimental pulmonary metastasis. Similar antitumor and antimetastatic activities of IL-27 were also observed in IFN-gamma knockout mice. In NOD-SCID mice, these activities were decreased, but were still fairly well-retained, suggesting that different mechanisms other than the immune response are also involved in the exertion of these activities. Immunohistochemical analyses with Abs against vascular endothelial growth factor and CD31 revealed that B16F10 + IL-27 cells markedly suppressed tumor-induced neovascularization in lung metastases. Moreover, B16F10 + IL-27 cells clearly inhibited angiogenesis by dorsal air sac method, and IL-27 exhibited dose-dependent inhibition of angiogenesis on chick embryo chorioallantoic membrane. IL-27 was revealed to directly act on HUVECs and induce production of the antiangiogenic chemokines, IFN-gamma-inducible protein (IP-10) and monokine induced by IFN-gamma. Finally, augmented mRNA expression of IP-10 and monokine induced by IFN-gamma was detected at the s.c. B16F10 + IL-27 tumor site, and antitumor activity of IL-27 was partially inhibited by the administration of anti-IP-10. These results suggest that IL-27 possesses potent antiangiogenic activity, which plays an important role in its antitumor and antimetastatic activities.     

Synergistic engagement of an ineffective endogenous anti-tumor immune response and induction of IFN-gamma and Fas-ligand-dependent tumor eradication by combined administration of IL-18 and IL-2

IFN-gamma is a critical component of the endogenous and many cytokine-induced antitumor immune responses. In this study we have shown that the combination of IL-18 and IL-2 (IL-18/IL-2) synergistically enhances IFN-gamma production both in vitro and in vivo, and synergizes in vivo to induce complete durable regression of well-established 3LL tumors in >80% of treated mice. We have observed a nascent, but ineffective, host immune response against 3LL that depends on endogenous IFN-gamma and IL-12 production and the Fas/Fas ligand (Fas-L) pathway. The combined administration of IL-18/IL-2 engages this endogenous response to induce tumor regression via a mechanism that is independent of NK and NKT cells or IL-12, but is critically dependent on CD8(+) T cells, IFN-gamma, and the Fas/Fas-L pathway. These studies demonstrate the importance of IFN-gamma as well as the Fas/Fas-L pathway in both endogenous and cytokine-driven antitumor immune responses engaged by IL-18/IL-2 and provide preclinical impetus for clinical investigation of this potent anti-tumor combination.     

Cytogenesis of murine mammary tumors in BALB/cfC3H and BALB/cfRIII strains

Biological and morphological differences in the mammary tumors of BALB/cfC3H and BALB/cfRIII mice are due to differences in the causative viruses. The C3H and RIII variants of the murine mammary tumor virus (MuMTV) might give origin to different mammary tumors by transforming different types of cell, i.e. epithelial or myoepithelial cells. The nature (epithelial or myoepithelial) of the neoplastic cells has been investigated by demonstrating their plasma membrane ATPase activities. We found that in normal murine mammary gland both epithelium and myoepithelium have Mg++ dependent ATPase activity, while the myoepithelium shows in addition an Na+K+ dependent ATPase activity. It is suggested that the results obtained exclude the participation of myoepithelium to the neoplastic growth and we ascribe the differences in mammary tumors of the two strains of mice to differences in the mechanisms of action of the virus variants.     

Blockade of Fas Signaling in Breast Cancer Cells Suppresses Tumor Growth and Metastasis via Disruption of Fas Signaling-initiated Cancer-related Inflammation

Mechanisms for cancer-related inflammation remain to be fully elucidated. Non-apoptotic functions of Fas signaling have been proposed to play an important role in promoting tumor progression. It has yet to be determined if targeting Fas signaling can control tumor progression through suppression of cancer-related inflammation. In the current study we found that breast cancer cells with constitutive Fas expression were resistant to apoptosis induction by agonistic anti-Fas antibody (Jo2) ligation or Fas ligand cross-linking. Higher expression of Fas in human breast cancer tissue has been significantly correlated with poorer prognosis in breast cancer patients. To determine whether blockade of Fas signaling in breast cancer could suppress tumor progression, we prepared an orthotopic xenograft mouse model with mammary cancer cells 4T1 and found that blockade of Fas signaling in 4T1 cancer cells markedly reduced tumor growth, inhibited tumor metastasis in vivo, and prolonged survival of tumor-bearing mice. Mechanistically, blockade of Fas signaling in cancer cells significantly decreased systemic or local recruitment of myeloid derived suppressor cells (MDSCs) in vivo. Furthermore, blockade of Fas signaling markedly reduced IL-6, prostaglandin E2 production from breast cancer cells by impairing p-p38, and activity of the NFκB pathway. In addition, administration of a COX-2 inhibitor and anti-IL-6 antibody significantly reduced MDSC accumulation in vivo. Therefore, blockade of Fas signaling can suppress breast cancer progression by inhibiting proinflammatory cytokine production and MDSC accumulation, indicating that Fas signaling-initiated cancer-related inflammation in breast cancer cells may be a potential target for treatment of breast cancer.     

IL-12 and IL-10 expression synergize to induce the immune-mediated eradication of established colon and mammary tumors and lung metastasis

Preclinical studies demonstrated that certain cytokines are potentially useful for the induction of antitumor immune responses. However, their administration in clinical settings was only marginally useful and evoked serious toxicity. In this study, we demonstrate that the combination of autologous inactivated tumor cells expressing IL-12 and IL-10 induced tumor remission in 50-70% of mice harboring large established colon or mammary tumors and spontaneous lung metastases, with the consequent establishment of an antitumor immune memory. Mice treatment with tumor cells expressing IL-12 was only marginally effective, while expression of IL-10 was not effective at all. Administration of the combined immunotherapy stimulated the recruitment of a strong inflammatory infiltrate that correlated with local, increased expression levels of the chemokines MIP-2, MCP-1, IFN-gamma-inducible protein-10, and TCA-3 and the overexpression of IFN-gamma, but not IL-4. The combined immunotherapy was also therapeutically effective on established lung metastases from both colon and mammary tumors. The antitumor effect of the combined immunotherapy was mainly dependent on CD8+ cells although CD4+ T cells also played a role. The production of IFN-gamma and IL-4 by spleen cells and the development of tumor-specific IgG1 and IgG2a Abs indicate that each cytokine stimulated its own Th pathway and that both arms were actively engaged in the antitumor effect. This study provides the first evidence of a synergistic antitumor effect of IL-12 and IL-10 suggesting that a Th1 and a Th2 cytokine can be effectively combined as a novel rational approach for cancer immunotherapy.     

IL-4 diminishes perforin-mediated and increases Fas ligand-mediated cytotoxicity In vivo

CTL have evolved two major mechanisms for target cell killing: one mediated by perforin/granzyme secretion and the other by Fas/Fas ligand (L) interaction. Although cytokines are integral to the development of naive CTL into cytolytic effectors, the role of cytokines on mechanisms of CTL killing is just emerging. In this study, we evaluate the effects of IL-4 in Fas(CD95)/FasL(CD95L)-mediated killing of Fas-overexpressing target cells. Recombinant vaccinia viruses (vv) were constructed to express respiratory syncytial virus M2 Ag alone (vvM2) or coexpress M2 and IL-4 (vvM2/IL-4). MHC-matched Fas-overexpressing target cells (L1210Fas+) were used to measure both perforin- and FasL-mediated killing pathways. In contrast to Fas-deficient (L1210Fas-) target cells, effectors from vvM2/IL-4-immunized mice were able to lyse L1210Fas+ target cells with similar magnitude as vvM2-infected mice. Addition of EGTA/Mg2+ revealed that effectors from vvM2/IL-4-infected mice primarily lyse targets by a Ca2+-independent Fas/FasL pathway. Analysis of FasL expression by flow cytometry showed that IL-4 increased cell surface FasL expression on CD4+ and CD8+ splenocytes, with peak expression on day 4 after infection. These data demonstrate that IL-4 increases FasL expression on T cells, resulting in a shift of the mechanism of CTL killing from a dominant perforin-mediated cytolytic pathway to a dominant FasL-mediated cytolytic pathway.     

Fas ligand induces cell-autonomous IL-23 production in dendritic cells, a mechanism for Fas ligand-induced IL-17 production

Fas ligand (FasL) has the potential to induce inflammation accompanied by massive neutrophil infiltration. We previously reported that FasL rapidly induces the production of various inflammatory cytokines including IL-1beta and IL-17. In this study, we investigated the mechanism of the FasL-induced IL-17 production. We found that the culture supernatant of mouse resident peritoneal exudate cells (PEC) cocultured with FasL-expressing tumor (FFL) cells induced IL-17 production in freshly isolated resident PEC. Anti-IL-1beta Ab strongly inhibited the IL-17-inducing activity. However, rIL-1beta by itself induced only weak IL-17 production. Intriguingly, anti-IL-12 Ab but not an IL-15-neutralizing agent, IL15R-Fc, strongly inhibited the FasL-induced IL-17-inducing activity. IL-23, which shares the p40 subunit with IL-12, but not IL-12 itself, induced IL-17 production synergistically with IL-1beta in resident PEC. FasL induced the production of IL-23 in PEC in vivo and in vitro, and IL-17 production following the i.p. injection of FFL cells was severely impaired in p40-/- mice, indicating that IL-23 plays an important role in the FasL-induced IL-17 production. FFL also induced the production of IL-23 in bone marrow- or PEC-derived dendritic cells (DCs). Finally, FasL induced only weak p40 production in a mixture of p40-/- and Fas-/- DC, indicating that FasL induces IL-23 production in DC mainly in a cell-autonomous manner.     

Combined delivery of an antiangiogenic protein (angiostatin) and an immunomodulatory gene (interleukin-12) in the treatment of murine cancer

We investigated the feasibility of a novel therapeutic approach to treat neoplastic diseases in mice. This novel strategy consists in delivering a protein (angiostatin) with strong antiangiogenic properties, followed by administration of the interleukin 12 gene that is strongly immunomodulatory and has also some antiangiogenic effects. When angiostatin-mediated antiangiogenic therapy was used in combination with intratumor delivery of the IL-12 gene (a strategy much safer than IL-12 protein administration), this produced a synergistic therapeutic effect.     

Fas/FasL expression in colorectal cancer. An immunohistochemical study

The objective of the current study was to assess the expression of Fas ligand (FasL) and Fas receptor (FasR) as the proteins of the post-mitochondrial apoptotic pathway in colorectal carcinoma and to investigate correlations between their expression and chosen clinico-pathological parameters. The protein expression was analyzed in 50 colorectal carcinoma patients, using the immunohistochemical method. Reaction for FasR was weak in 75.5% and strong in 24.5% of the study patients, as compared to normal glandular epithelium where FasR expression was strong in 100% of cases. On the other hand, FasL expression was found to be weak in 30% and strong in 70% of colorectal cancer patients, as compared to its lack in 100% of normal colorectal epithelium. Statistical analysis showed strong expression of FasL was found to correlate statistically significantly with vascular invasion (p = 0.005). No correlations of FasL and FasR expression in the main mass of tumor was found between other clinic-pathological parameters. Fas ligand and Fas receptor appeared to be of little usefulness as prognostic factors for different groups of colorectal carcinoma patients. However, these proteins could become good therapeutic targets for colorectal carcinoma since their expression differs distinctly between normal intestinal epithelium and cancer cells, and known is the mechanism by which cancer cells escape death via apoptosis-inducing Fas/FasL pathway disorders.     

Fas and Fas ligand mutations inhibit autoantibody production in pristane-induced lupus

Mutations of Fas (lpr) or Fas ligand (gld) cause a limited lupus-like syndrome in B6 mice by interfering with the deletion of autoreactive B and/or T cells. A more generalized lupus syndrome reminiscent of that of MRL mice can be induced in nonautoimmune strains by pristane, which causes a nonspecific inflammatory response in the peritoneal cavity. We hypothesized that, as in MRL mice, the lpr and gld mutations might accelerate lupus in pristane-treated mice. Pristane-treated B6 mice developed anti-nRNP/Sm, Su, and ribosomal P Abs, but little anti-ssDNA or chromatin. In contrast, B6/lpr and B6/gld mice spontaneously developed anti-ssDNA/chromatin Abs, but not anti-nRNP/Sm/Su/ribosomal P. Unexpectedly, B6/lpr and B6/gld mice were highly resistant to the induction by pristane of IgM anti-ssDNA (2 wk) and IgG anti-nRNP/Sm/Su/ribosomal P autoantibodies (6 mo), suggesting that intact Fas signaling is necessary. Interestingly, pristane did not enhance IgG chromatin Ab production in B6/lpr or B6/gld mice, suggesting that it did not influence the production of autoantibodies that develop spontaneously in the setting of Fas deficiency. Pristane treatment also decreased lymphoproliferation in B6/lpr mice. Increased production of IL-12 was associated consistently with the production of anti-nRNP/Sm/Su/ribosomal P as well as anti-DNA/chromatin. In contrast, production of anti-DNA/chromatin Abs was associated with IL-6 overproduction in pristane-treated mice, but not in lpr mice. The data strongly support the idea that different subsets of autoantibodies are regulated differentially by cytokine stimulation and/or Fas signaling.     

Cytogenesis of murine mammary tumors in BALB/cfC3H and BALB/cfRIII strains

Summary Biological and morphological differences in the mammary tumors of BALB/cfC3H and BALB/cfRIII mice are due to differences in the causative viruses. The C3H and RIII variants of the murine mammary tumor virus (MuMTV) might give origin to different mammary tumors by transforming different types of cell, i.e. epithelial or myoepithelial cells. The nature (epithelial or myoepithelial) of the neoplastic cells has been investigated by demonstrating their plasma membrane ATPase activities. We found that in normal murine mammary gland both epithelium and myoepithelium have Mg⁺⁺ dependent ATPase activity, while the myoepithelium shows in addition an Na⁺ K⁺ dependent ATPase activity. It is suggested that the results obtained exclude the participation of myoepithelium to the neoplastic growth and we ascribe the differences in mammary tumors of the two strains of mice to differences in the mechanisms of action of the virus variants.Supported by contract No. 79.00431.84 from the National Research Council, Rome, Progetto Finalizzato CNR Virus     

IL-27 mediates complete regression of orthotopic primary and metastatic murine neuroblastoma tumors: role for CD8+ T cells

We have shown previously that IFN-gamma-inducing cytokines such as IL-12 can mediate potent antitumor effects against murine solid tumors. IL-27 is a newly described IL-12-related cytokine that potentiates various aspects of T and/or NK cell function. We hypothesized that IL-27 might also mediate potent antitumor activity in vivo. TBJ neuroblastoma cells engineered to overexpress IL-27 demonstrated markedly delayed growth compared with control mice, and complete durable tumor regression was observed in >90% of mice bearing either s.c. or orthotopic intra-adrenal tumors, and 40% of mice bearing induced metastatic disease. The majority of mice cured of their original TBJ-IL-27 tumors were resistant to tumor rechallenge. Furthermore, TBJ-IL-27 tumors were heavily infiltrated by CD8(+) T cells, and draining lymph node-derived lymphocytes from mice bearing s.c. TBJ-IL-27 tumors are primed to proliferate more readily when cultured ex vivo with anti-CD3/anti-CD28 compared with lymphocytes from mice bearing control tumors, and to secrete higher levels of IFN-gamma. In addition, marked enhancement of local IFN-gamma gene expression and potent up-regulation of cell surface MHC class I expression are noted within TBJ-IL-27 tumors compared with control tumors. Functionally, these alterations occur in conjunction with the generation of tumor-specific CTL reactivity in mice bearing TBJ-IL-27 tumors, and the induction of tumor regression via mechanisms that are critically dependent on CD8(+), but not CD4(+) T cells or NK cells. Collectively, these studies suggest that IL-27 could be used therapeutically to potentiate the host antitumor immune response in patients with malignancy.     

Upregulation of Fas in epithelial ovarian cancer reverses the development of resistance to Cisplatin

This study was to investigate the role of Fas in the development of Cisplatin-resistant ovarian cancer. On the cellular level, Fas expression was significantly reduced in Cisplatin resistant A2780 (A2780/CP) cells compared with A2780 cells. Fas silence with siRNA would promote tumor cell lines proliferation, facilitate tumor cell cycle transition of G1/S, prevent cell apoptosis, and promote cell migration. Expression of drug resistance gene was negatively correlated to Fas. In nude mice metastasis model of human ovarian carcinoma by subcutaneous transplantation, after Ad-Fas injected intratumorly, we found that upregulation of Fas could inhibit transplantation tumor tissue growth and reduce the expression of drug resistance gene. Our results indicated that upregulation of Fas in epithelial ovarian cancer reversed the development of resistance to Cisplatin. In conclusion, our findings suggested that Fas might act as a promising therapeutic target for improvement of the sensibility to Cisplatin in ovarian cancer. [BMB Reports 2015; 48(1): 30-35]     

Chronic chemoimmunotherapy achieves cure of spontaneous murine mammary tumors via persistent blockade of posttherapy counter-regulation

Intratumoral delivery of IL-12 and GM-CSF induces local and systemic antitumor CD8(+) T cell activation and tumor kill. However, the effector response is transient and is rapidly countered by CD4(+) Foxp3(+) T suppressor cell expansion. To determine whether depletion of the pre-existing T suppressor cell pool prior to treatment could diminish posttherapy regulatory cell resurgence, FVBneuN mice bearing advanced spontaneous mammary tumors were treated with cyclophosphamide (CY) 1 d before IL-12/GM-CSF therapy. Administration of CY mediated a significant delay in the post-IL-12/GM-CSF T suppressor cell rebound, resulting in a 7-fold increase in the CD8(+) CTL/T suppressor cell ratio, a 3-fold enhancement of CTL cytotoxicity, and an extension of the effector window from 3 to 7 d. In long-term therapy studies, chronic chemoimmunotherapy promoted a dramatic enhancement of tumor regression, resulting in complete cure in 44% of the mice receiving CY plus IL-12/GM-CSF. Tumor eradication in the chronic therapy setting was associated with the ability to repeatedly rescue and maintain cytotoxic CD8(+) T cell activity. These findings demonstrated that chronic administration of CY in conjunction with immune therapy enhances the initial induction of antitumor T effector cells and, more importantly, sustains their cytotoxic activity over the long-term via persistent blockade of homeostatic counter-regulation.