Elena Quaglino

DNA Vaccination Against Rat Her-2/Neu p185 More Effectively Inhibits Carcinogenesis Than Transplantable Carcinomas in Transgenic BALB/c Mice

The ability of vaccination with plasmids coding for the extracellular and the transmembrane domain of the product of transforming rat Her-2/neu oncogene (r-p185) to protect against r-p185+ transplantable carcinoma (TUBO) cells and mammary carcinogenesis was evaluated. In normal BALB/c mice, DNA vaccination elicits anti-r-p185 Ab, but only a marginal CTL reactivity, and protects against a TUBO cell challenge. Massive reactive infiltration is associated with TUBO cell rejection. In BALB/c mice transgenic for the rat Her-2/neu gene (BALB-neuT), DNA vaccination elicits a lower anti-r-p185 Ab response, no CTL activity and only incompletely protects against TUBO cells, but markedly hampers the progression of carcinogenesis. At 33 wk of age, when control BALB-neuT mice display palpable tumors in all mammary glands, about 60% of immunized mice are tumor free, and tumor multiplicity is markedly reduced. Tumor-free mammary glands still display the atypical hyperplasia of the early stages of carcinogenesis, and a marked down-modulation of r-p185, along with a massive reactive infiltrate. However, BALB-neuT mice protected against mammary carcinogenesis fail to efficiently reject a TUBO cell challenge. This suggests that the mechanisms required for the rejection of transplantable tumors may not coincide with those that inhibit the slow progression of carcinogenesis.

microRNA-214 contributes to melanoma tumour progression through suppression of TFAP2C

Malignant melanoma is fatal in its metastatic stage. It is therefore essential to unravel the molecular mechanisms that govern disease progression to metastasis. MicroRNAs (miRs) are endogenous non‐coding RNAs involved in tumourigenesis. Using a melanoma progression model, we identified a novel pathway controlled by miR‐214 that coordinates metastatic capability. Pathway components include TFAP2C, homologue of a well‐established melanoma tumour suppressor, the adhesion receptor ITGA3 and multiple surface molecules. Modulation of miR‐214 influences in vitro tumour cell movement and survival to anoikis as well as extravasation from blood vessels and lung metastasis formation in vivo. Considering that miR‐214 is known to be highly expressed in human melanomas, our data suggest a critical role for this miRNA in disease progression and the establishment of distant metastases.

Tailoring DNA Vaccines: Designing Strategies Against HER2-Positive Cancers

The crucial role of HER2 in epithelial transformation and its selective overexpression on cancer tissues makes it an ideal target for cancer immunotherapies such as passive immunotherapy with Trastuzumab. There are, however, a number of concerns regarding the use of monoclonal antibodies which include resistance, repeated treatments, considerable costs, and side effects that make active immunotherapies against HER2 desirable alternative approaches. The efficacy of anti-HER2 DNA vaccination has been widely demonstrated in transgenic cancer-prone mice, which recapitulate several features of human breast cancers. Nonetheless, the rational design of a cancer vaccine able to trigger a long-lasting immunity, and thus prevent tumor recurrence in patients, would require the understanding of how tolerance and immunosuppression regulate antitumor immune responses and, at the same time, the identification of the most immunogenic portions of the target protein. We herein retrace the findings that led to our most promising DNA vaccines that, by encoding human/rat chimeric forms of HER2, are able to circumvent peripheral tolerance. Preclinical data obtained with these chimeric DNA vaccines have provided the rationale for their use in an ongoing Phase I clinical trial (EudraCT 2011-001104-34).

Electroporated DNA Vaccine Clears Away Multifocal Mammary Carcinomas in Her-2/neu Transgenic Mice

The transforming rat Her-2/neu oncogene embedded into the genome of virgin transgenic BALB/c mice (BALB-neuT) provokes the development of an invasive carcinoma in each of their 10 mammary glands. i.m. vaccination with DNA plasmids coding for the extracellular and transmembrane domains of the protein product of the Her-2/neu oncogene started when mice already display multifocal in situ carcinomas temporarily halts neoplastic progression, but all mice develop a tumor by week 43. By contrast, progressive clearance of neoplastic lesions and complete protection of all 1-year-old mice are achieved when the same plasmids are electroporated at 10-week intervals. Pathological findings, in vitro tests, and the results from the immunization of both IFN-gamma and immunoglobulin gene knockout BALB-neuT mice, and of adoptive transfer experiments, all suggest that tumor clearance rests on the combination of antibodies and IFN-gamma-releasing T cells. These findings show that an appropriate vaccine effectively inhibits the progression of multifocal preneoplastic lesions.

Zoledronic acid repolarizes tumour-associated macrophages and inhibits mammary carcinogenesis by targeting the mevalonate pathway

It is unknown whether zoledronic acid (ZA) at clinically relevant doses is active against tumours not located in bone. Mice transgenic for the activated ErbB‐2 oncogene were treated with a cumulative number of doses equivalent to that recommended in human beings. A significant increase in tumour‐free and overall survival was observed in mice treated with ZA. At clinically compatible concentrations, ZA modulated the mevalonate pathway and affected protein prenylation in both tumour cells and macrophages. A marked reduction in the number of tumour‐associated macrophages was paralleled by a significant decrease in tumour vascularization. The local production of vascular endothelial growth factor and interleukin‐10 was drastically down‐regulated in favour of interferon‐γ production. Peritoneal macrophages and tumour‐associated macrophages of ZA‐treated mice recovered a full M1 antitumoral phenotype, as shown by nuclear translocation of nuclear factor kB, inducible nitric oxide synthase expression and nitric oxide production. These data indicate that clinically achievable doses of ZA inhibit spontaneous mammary cancerogenesis by targeting the local microenvironment, as shown by a decreased tumour vascularization, a reduced number of tumour‐associated macrophages and their reverted polarization from M2 to M1 phenotype.

Nonredundant roles of antibody, cytokines, and perforin in the eradication of established Her-2/neu carcinomas

Since the mechanisms by which specific immunity destroys Her-2/neu carcinoma cells are highly undetermined, these were assessed in BALB/c mice vaccinated with plasmids encoding extracellular and transmembrane domains of the protein product (p185(neu)) of the rat Her-2/neu oncogene shot into the skin by gene gun. Vaccinated mice rejected a lethal challenge of TUBO carcinoma cells expressing p185(neu). Depletion of CD4 T cells during immunization abolished the protection, while depletion of CD8 cells during the effector phase halved it, and depletion of polymorphonuclear granulocytes abolished all protection. By contrast, Ig mu-chain gene KO mice, as well as Fcgamma receptor I/III, beta-2 microglobulin, CD1, monocyte chemoattractant protein 1 (MCP1), IFN-gamma, and perforin gene KO mice were protected. Only mice with both IFN-gamma and perforin gene KOs were not protected. Although immunization also cured all BALB/c mice bearing established TUBO carcinomas, it did not cure any of the perforin KO or perforin and IFN-gamma KO mice. Few mice were cured that had knockouts of the gene for Ig mu-chain, Fcgamma receptor I/III, IFN-gamma, or beta-2 microglobulin. Moreover, vaccination cured half of the CD1 and the majority of the MCP1 KO mice. The eradication of established p185(neu) carcinomas involves distinct mechanisms, each endowed with a different curative potential.

Constitutively active Stat3 enhances neu-mediated migration and metastasis in mammary tumors via upregulation of Cten.

The transcription factor signal transducer and activator of transcription 3 (STAT3) is constitutively activated in tumors of different origin, but the molecular bases for STAT3 requirement are only partly understood. To evaluate the contribution of enhanced Stat3 activation in a controlled model system, we generated knock-in mice wherein a mutant constitutively active Stat3C allele replaces the endogenous wild-type allele. Stat3C could enhance the tumorigenic power of the rat Neu oncogene in mouse mammary tumor virus (MMTV)-Neu transgenic mice, triggering the production of earlier onset, more invasive mammary tumors. Tumor-derived cell lines displayed higher migration, invasion, and metastatic ability and showed disrupted distribution of cell-cell junction markers mediated by Stat3-dependent overexpression of the COOH terminal tensin-like (Cten) focal adhesion protein, which was also significantly upregulated in Stat3C mammary tumors. Importantly, the proinflammatory cytokine interleukin-6 could mediate Cten induction in MCF10 cells in an exquisitely Stat3-dependent way, showing that Cten upregulation is a feature of inflammation-activated Stat3. In light of the emerging pivotal role of Stat3 in connecting inflammation and cancer, our identification of Cten as a Stat3-dependent mediator of migration provides important new insights into the oncogenic role of Stat3, particularly in the breast.

Concordant morphologic and gene expression data show that a vaccine halts HER-2/neu preneoplastic lesions

While much experimental data shows that vaccination efficiently inhibits a subsequent challenge by a transplantable tumor, its ability to inhibit the progress of autochthonous preneoplastic lesions is virtually unknown. In this article, we show that a combined DNA and cell vaccine persistently inhibits such lesions in a murine HER-2/neu mammary carcinogenesis model. At 10 weeks of age, all of the ten mammary gland samples from HER-2/neu-transgenic mice displayed foci of hyperplasia that progressed to invasive tumors. Vaccination with plasmids coding for the transmembrane and extracellular domain of rat p185neu followed by a boost with rp185neu+ allogeneic cells secreting IFN-gamma kept 48% of mice tumor free. At 22 weeks, their mammary glands were indistinguishable from those of 10-week-old untreated mice. Furthermore, the transcription patterns of the two sets of glands coincided. Of the 12,000 genes analyzed, 17 were differentially expressed and related to the antibody response. The use of B cell knockout mice as well as the concordance of morphologic and gene expression data demonstrated that the Ab response is the main mechanism facilitating tumor growth arrest. This finding suggests that a new way can be found to secure the immunologic control of the progression of HER-2/neu preneoplastic lesions.

miR148b is a major coordinator of breast cancer progression in a relapse-associated microRNA signature by targeting ITGA5, ROCK1, PIK3CA, NRAS, and CSF1

Breast cancer is often fatal during its metastatic dissemination. To unravel the role of microRNAs (miRs) during malignancy, we analyzed miR expression in 77 primary breast carcinomas and identified 16 relapse‐associated miRs that correlate with survival and/or distinguish tumor subtypes in different datasets. Among them, miR‐148b, down‐regulated in aggressive breast tumors, was found to be a major coordinator of malignancy. In fact, it is able to oppose various steps of tumor progression when overexpressed in cell lines by influencing invasion, survival to anoikis, extravasation, lung metastasis formation, and chemotherapy response. miR‐148b controls malignancy by coordinating a novel pathway involving over 130 genes and, in particular, it directly targets players of the integrin signaling, such as ITGA5, ROCK1, PIK3CA/p110α, and NRAS, as well as CSF1, a growth factor for stroma cells. Our findings reveal the importance of the identified 16 miRs for disease outcome predictions and suggest a critical role for miR‐148b in the control of breast cancer progression.—Cimino, D., De Pittà, C., Orso, F., Zampini, M., Casara, C., Penna, E., Quaglino, E., Forni, M., Damasco, C., Pinatel, E., Ponzone, R., Romualdi, C., Brisken, C., De Bortoli, M., Biglia, N., Provero, P., Lanfranchi, G., Taverna, D. miR148b is a major coordinator of breast cancer progression in a relapse‐associated microRNA signature by targeting ITGA5, ROCK1, PIK3CA, NRAS, and CSF1. FASEB J. 27, 1223–1235 (2013). www.fasebj.org

Insertion of the DNA for the 163-171 peptide of IL1beta enables a DNA vaccine encoding p185(neu) to inhibit mammary carcinogenesis in Her-2/neu transgenic BALB/c mice.

An assessment was made of the effectiveness of DNA vaccination in prevention of the mammary adenocarcinomas of BALB/c female mice transgenic for the activated rat Her-2/neu oncogene. Atypical hyperplasia is evident in their mammary glands when they are 6 weeks old and in situ carcinoma by the 13th week. Palpable invasive carcinomas appear around the 17th week and are always evident in all 10 glands by the 33rd week. Intramuscular vaccinations with 100 μg plasmid DNA encoding the extracellular domain of the Her-2/neu p185 (ECD) performed at the 6th, 12th, 18th and 24th week provided no significant protection, whereas those ECD plasmids in which the DNA coding for the immunomodulatory 163–171 (VQGEESNDK) nonapeptide of human IL1β (ECD-IL1βp) had been inserted both delayed carcinogenesis and reduced tumor multiplicity. This reduction was associated with a marked immune-inflammatory reaction and a conspicuous leukocyte infiltrate located in the stroma surrounding the hyperplastic mammary ductul-alveolar structures. It was also directly correlated with a high anti-p185neu antibody production and an immunoglobulin switch to IgG2a and IgA. No anti-p185neu cytotoxic response was found. No significant protection was obtained when the DNA coding for the non-active peptide 189–197 of IL1β was inserted.