HCG hastens both the development of mammary carcinoma and the metastatization of HCG/LH and ERBB-2 receptor-positive cells in mice.

Breast cancer is more frequent in human nulliparae, whereas its incidence is reduced by early fullterm pregnancy. Rodent studies suggest that chorionic gonadotropin secretion during pregnancy affords protection by inducing breast structure differentiation. Opposite effects, however, have been observed in cancer prone transgenic mice overexpressing the ß subunit of chorionic gonadotropin or pituitary luteinic hormone (LH). Here we assessed the effect of administration of human chorionic gonadotropin (hCG) for 21 days (corresponding to the duration of a mouse pregnancy) in virgin female mice transgenic for the activated rat (r-) ERBB-2 oncogene (BALB-neuT). In these mice, the onset of atypical mammary duct hyperplasia and its progression towards multiple mammary carcinomas is accelerated by hCG. hCG enhances the in vitro proliferation and in vivo metastatization of tumor cells from a BALB-neuT mammary tumor expressing the hCG/LH as well as the ERBB-2 receptors. These findings suggest that hCG favours the growth and progression of hCG/LH and ERBB-2 receptor-positive breast tumors.

A multi-DNA preventive vaccine for p53/Neu-driven cancer syndrome.

The highly aggressive cancer syndrome of female mice carrying a p53 knockout allele and a rat HER-2/neu (Neu) transgene (BALB-p53Neu) can be prevented by a cell vaccine presenting three components: Neu, interleukin (IL)-12 production, and allogeneic major histocompatibility complex (MHC) alleles (Triplex cell vaccine). Here we tested a second-generation Triplex DNA-based vaccine (Tri-DNA), consisting of the combination of three gene components (a transmembrane-extracellular domain fragment of the Neu gene, IL-12 genes, and the H-2D(q) allogeneic MHC gene), carried by separate plasmids. The Tri-DNA vaccine was at least as effective as the Triplex cell vaccine for cancer immunoprevention, giving a similar delay in the onset of mammary cancer and complete protection from salivary cancer. Both vaccines induced anti-Neu antibodies of the murine IgG2a isotype at similar levels. The Tri-DNA vaccine gave more restricted immunostimulation, consisting of a fully helper T cell type 1 (Th1)-polarized response, with effective production of interferon (IFN)-gamma in response to the vaccine but no spontaneous production, and no induction of anti-Neu IgG3 antibodies. On the other hand, the Triplex cell vaccine induced both Th1 and Th2 cytokines, a strong increase in spontaneous IFN-gamma production, and high levels of IgG3 antibodies recognizing Neu-positive syngeneic cells. In conclusion, the Tri-DNA vaccine is as effective as Triplex cell vaccine, exploiting a more restricted immune stimulation.

Effects of castration on the development of prostate adenocarcinoma from its precursor HGPIN and on the occurrence of androgen-independent, poorly differentiated carcinoma in TRAMP mice.

Androgen ablation is thought to exert selective pressure for the development of androgen-independent forms of prostate cancer. This study was set up to investigate the effects of surgical castration on the development of prostate adenocarcinoma (ADC) from its precursor (high-grade prostate intraepithelial neoplasia (HGPIN)) and on the occurrence of androgen-independent, poorly differentiated carcinoma (PDC) in (C57Bl/6 transgenic adenocarcinoma of mouse prostate) TRAMP mice. It was found that castration cures HGPIN and ADC and prevents their further occurrence and growth, but has no effect on PDC. This indicates that in this model, PDC is not the progression of ADC favoured by androgen ablation and that its initiating cells are different from those of HGPIN and ADC.

WIP null mice display a progressive immunological disorder that resembles Wiskott-Aldrich syndrome.

The Wiskott-Aldrich syndrome (WAS) is an X-linked immunodeficiency syndrome caused by mutations in the WAS protein (WASP). This participates in signalling and cytoskeletal homoeostasis, and some of its activities are regulated by its binding to the WASP interacting protein (WIP). WIP deficiency, however, has not yet been shown to be of pathological significance in humans. Here we show that, in WIP null (WIP(-/-)) mice, it produces haematological alterations and anatomical abnormalities in several organs, most probably as a consequence of autoimmune attacks. Granulocytosis and severe lymphopenia are associated with a proportional increase in segmented cells and fewer bone marrow erythrocytes and lymphocytes. Splenomegaly is accompanied by an increase of haematopoietic tissue and red pulp, reduction of the white pulp, and fewer B (B220(+)) lymphocytes (also apparent in the lymph nodes and Peyer's patches). Ulcerative colitis, interstitial pneumonitis, glomerular nephropathy with IgA deposits, autoantibodies, and joint inflammation are also evident. These progressive immunological disorders closely mimic those seen in WAS. WIP deficiency may thus be implicated in some cases in which mutations in the gene encoding WASP are not detected.

A limited autoimmunity to p185neu elicited by DNA and allogeneic cell vaccine hampers the progression of preneoplastic lesions in HER-2/NEU transgenic mice.

Prevention of the progression of precancerous lesions by vaccines is virtually uncharted territory. Their potential, however, is being assessed in transgenic mice which develop autochthonous tumors with defined stages of progression. In this paper we show that the DNA micro-array technology significantly helps assessment of the preventive efficacy of a combined DNA and cell vaccine. All female rat Her-2/neu transgenic BALB/c (BALB-neuT) mice develop an invasive carcinoma in each of their mammary glands within 25 weeks of age. This is elicited by the activated transforming rat Her-2/neu oncogene embedded in their genome. We have previously shown that vaccination of mice bearing multiple in situ carcinomas with DNA plasmids which code for the extracellular and transmembrane domain of rat p185neu, the product of the rat Her-2/neu oncogene, followed by a boost with rat p185neu+ allogeneic cells engineered to secrete interferon-gamma, keeps 48% of mice tumor free until week 32. We have now extended our follow-up until mice reach one year of age and show that protection vanishes as time progresses. This observation suggests that the accuracy of the results studying immunotherapy against life-threatening tumors is a function of the length of the follow-up. The application of microarrays, and the concordance of morphologic and gene expression data led us to identify antibody as the main mechanism induced by vaccination. Protection is associated with a break of tolerance and a limited autoimmunity against the endogenous mouse p185neu.

The expression of LEC/CCL16, a powerful inflammatory chemokine, is upregulated in ulcerative colitis.

Ulcerative colitis (UC) is a chronic inflammatory disease of unknown aetiology and pathogenesis. The presence in the colonic mucosa of reactive cells expressing proinflammatory cytokines and chemokines is associated with high levels of IL-10, an anti-inflammatory cytokine. Our aim was to investigate the role of IL-10 and the beta chemokine LEC/CCL16 selectively up-regulated by IL-10 in inflammatory cell recruitment and cytokine and chemokine production during UC. We studied histologically, immunohistochemically and ultrastructurally colonic biopsies from 20 active UC patients and 10 control specimens taken far from any macroscopically detectable lesion in age and sex-matched patients with noninflammatory bowel disease. In active UC, immature dendritic cells (DCs) in the LP are associated with IL-10 in the T cell rich area. Furthermore, most of the LP-infiltrating macrophages strongly expressed LEC/CCL16, a chemokine upregulated by IL-10. To evaluate if LEC/CCL16 plays a role in the inflammatory reaction present in UC, we performed morphological studies in mice injected s.c. with syngeneic tumor cells engineered to produce LEC/CCL16. We found that the LEC protein locally released by LEC-gene-transfected tumor cells is a potent proinflammatory chemokine that induces the recruitment of a reactive infiltrate, and an angiogenic process mirroring that in human UC.

Enhanced inhibition of tumour growth and metastasis, and induction of antitumour immunity by IL-2-IgG2b fusion protein.

Cytokine-immunoglobulin (Ig)-fusion proteins have attracted increasing interest as antitumour agents. Here, we have investigated the antimetastatic and antitumour responses elicited in vivo by mammary adenocarcinoma cells (TS/A) engineered to secrete interleukin (IL)-2-IgG fusion proteins. TS/A cells were transfected with DNA coding for IL-2-IgG2b, IgG2b or IL-2, and injected subcutaneously into syngeneic mice. Animals injected with TS/A-IL-2 or TS/A-IL-2-IgG2b both efficiently rejected tumours, whereas treatment with parental cells or TS/A-IgG2b was lethal. Interestingly, only mice vaccinated with IL-2-IgG2b fusion protein-secreting cells showed a long-lasting protective immunity against a later challenge with parental tumour cells. Moreover, the metastatic potential of TS/A-IL-2-IgG2b-transfected cells was dramatically decreased compared with TS/A-IL-2-cells, with a virtual absence of lung metastases after intravenous injection. Adenocarcinomas secreting IL-2-IgG2b exhibited a more prominent, early and persistent infiltration of CD4+, CD8+ and natural killer (NK) cells than TS/A-IL-2 cells. Therefore, upon transfection into adenocarcinoma cells, the IgG2b part of IL-2 fusion protein exerts intriguing added antitumour properties over IL-2 alone, thus contributing to a long-lasting tumour immunity, probably by the recruitment of specific immune effector cells. These findings suggest a promising new oncotherapeutic strategy for poorly immunogenic tumours: vaccination with tumour cells engineered to secrete IL-2-IgG2b fusion protein.

Combined allogeneic tumor cell vaccination and systemic interleukin 12 prevents mammary carcinogenesis in HER-2/neu transgenic mice.

Transgenic Balb/c mice expressing the transforming rat HER-2/neu oncogene develop early and multifocal mammary carcinomas. Within the first 5 months of life the tissue-specific expression of HER-2/neu causes a progression in all their 10 mammary glands from atypical hyperplasia to invasive carcinoma. It was previously observed that chronic administration of interleukin (IL)-12 increased tumor latency, but every mouse eventually succumbed to multiple carcinomas. A significant improvement in tumor prevention was sought by administering allogeneic mammary carcinoma cells expressing HER-2/neu combined with systemic IL-12. This treatment reduced tumor incidence by 90% and more than doubled mouse lifetime. For the maximum prevention p185(neu) antigen must be expressed by allogeneic cells. IL-12 treatment strongly increased the cell vaccine efficacy. The mammary glands of mice receiving the combined treatment displayed a markedly reduced epithelial cell proliferation, angiogenesis, and HER-2/neu expression, while the few hyperplastic foci were heavily infiltrated by granulocytes, macrophages, and CD8(+) lymphocytes. Specific anti-HER-2/neu antibodies were produced and a nonpolarized activation of CD4(+) and CD8(+) cells secreting IL-4 and interferon (IFN)-gamma were evident. A central role for IFN-gamma in the preventive effect was proven by the lack of efficacy of vaccination in IFN-gamma gene knockout HER-2/neu transgenic Balb/c mice. A possible requirement for IFN-gamma is related to its effect on antibody production, in particular on IgG2a and IgG2b subclasses, that were not induced in IFN-gamma knockout HER-2/neu mice. In conclusion, our data show that an allogeneic HER-2/neu-expressing cell vaccine combined with IL-12 systemic treatment can prevent the onset of genetically determined tumors.

1,2-Dimethylhydrazine-induced colon carcinoma and lymphoma in msh2(-/-) mice.

BACKGROUND: Defective mismatch repair (MMR) in humans is particularly associated with familial colorectal cancer, but defective repair in mice is generally associated with lymphoma in the absence of experimental exposure to carcinogens. Loss of MMR also confers resistance to the toxic effects of methylating agents. We investigated whether resistance to methylation contributes to increased susceptibility to colorectal cancer in mice by exposing mice with defects in the MMR gene msh2 to a methylating agent. METHODS: Tumor incidence and time of death in msh2(+/+), msh2(+/-), and msh2(-/-) mice were analyzed after weekly exposure (until tumor appearance) to the methylating agent 1,2-dimethylhydrazine (DMH). Chemically induced and spontaneous tumors were characterized by frequency, type, and location. The tumor incidence in untreated and treated mice of each genotype was compared by a Mann-Whitney U test. Carcinogen-induced apoptosis in histologic sections of small and large intestines was also determined. All statistical tests were two-sided. RESULTS: Homozygous inactivation of the msh2 gene statistically significantly accelerated (P<.0001) death due to the development of DMH-induced colorectal tumors and lymphomas. Rates of death from DMH-induced colorectal adenocarcinoma were similar in msh2 heterozygous and wild-type mice, but only msh2 heterozygotes (msh(+/-)) developed additional, noncolorectal malignancies (notably trichofolliculoma [two of 21], angiosarcoma of the kidney capsule [two of 21], and lymphoma [one of 21]), suggesting that heterozygosity for msh2 slightly increases DMH susceptibility. DMH induced apoptosis in small intestinal and colonic epithelial crypts that was dependent on active msh2. CONCLUSIONS: Inactivation of msh2 allows the proliferation of gastrointestinal tract cells damaged by methylating agents. Furthermore, MMR constitutes a powerful defense against colorectal cancer induced by DNA methylation.

Role of STAT3 and PI 3-kinase/Akt in mediating the survival actions of cytokines on sensory neurons.

The binding of cytokines to the gp130 receptor activates the STAT3, MEK/MAPK, and PI3K/Akt signalling pathways. To assess the relative importance of these pathways in promoting the survival of cytokine-dependent neurons, we conditionally inactivated STAT3 in mice and inhibited MEK, PI3K, and Akt in cultured neurons using pharmacological reagents and by expressing specific inhibitory proteins. Inactivation of STAT3 enhanced the death of the cytokine-dependent sensory neurons of the nodose ganglion in vivo and substantially reduced the response of these neurons to CNTF and LIF in vitro. LY294002, an inhibitor of PI3K, but not PD98059, an inhibitor of MEK, markedly reduced the response of these neurons to CNTF, as did dominant-negative PI3K, dominant-negative Akt, and overexpression of Ruk (a natural PI3K inhibitor). These results demonstrate that STAT3 and PI3K/Akt signalling play major roles in mediating the survival response of neurons to cytokines.

Prevention of spontaneous neu-expressing mammary tumor development in mice transgenic for rat proto-neu by DNA vaccination.

The HER-2/neu proto-oncogene is overexpressed in 20-30% of human breast cancers and is associated with high recurrence risk. The oncogenic potential of HER-2/neu, together with its elevated expression in tumors, cell surface localization, and immunogenicity in some patients, make this oncoprotein an ideal target for immunotherapeutic approaches. To test the efficacy of immune-based strategies in eliciting an antitumor response, we used the N#202 transgenic mouse model engineered to overexpress the rat neu proto-oncogene under the control of the mouse mammary tumor virus promoter; females of this line develop spontaneous focal mammary tumors by 6 months of age. Transgenic mice immunized intramuscularly with a HER-2 cDNA ligated into the VR1012 (VICAL) expression vector under the control of the cytomegalovirus promoter developed significantly fewer spontaneous tumors as compared with mice injected with the empty vector (P < 0.0001) or not injected (P = 0.0006). However, this protection was observed only when immunization was started in 3-month-old but not in 6-month-old mice. These data suggest that the xenogeneic HER-2 DNA sequence can break immune tolerance to rat neu in transgenic N#202 mice and induce protective immunity that impairs the neu oncogene-driven progression of mammary carcinogenesis. The preventive effect achieved by our immunological approach appeared not to be based on anti-neu specific B and T cell immune attacks but was more possibly based on different mechanisms including aspecific and inflammatory immunological responses.

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 microg 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 IL1beta (ECD-IL1betap) 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-p185(neu) antibody production and an immunoglobulin switch to IgG2a and IgA. No anti-p185(neu) cytotoxic response was found. No significant protection was obtained when the DNA coding for the non-active peptide 189-197 of IL1beta was inserted.

A light, nontoxic interleukin 12 protocol inhibits HER-2/neu mammary carcinogenesis in BALB/c transgenic mice with established hyperplasia.

With a slight asynchronous but consistent progression, all of the mammary glands of female BALB/c mice transgenic for the transforming rat HER-2/neu oncogene progress to atypical hyperplasia and to invasive carcinoma. Previous studies have shown that chronic administration of interleukin (IL) 12 started at the 2nd week of age hampers this progression because of its ability to inhibit tumor angiogenesis and activate a nonspecific immune response. Here we show that a similar inhibition is achieved when 7-week-old mice with fully blown atypical hyperplasia receive a weekly injection of 100 ng IL-12 for 16 times. This lower-dose and later IL-12 administration induces high and sustained levels of serum IFN-gamma equivalent to those elicited by more frequent administrations. A lower-dose and less toxic treatment may thus be envisaged as a possible option in the management of preneoplastic mammary lesions.

Interleukin 12-activated lymphocytes influence tumor genetic programs.

T-lymphocytes (LYs) from normal and IFN-gamma knockout mice were activated by anti-CD3 and anti-CD28 antibodies and cultured in inserts in the presence of interleukin (IL)-12 (IL-12-activated LYs) or not (activated LYs). Their ability to modulate the genetic programs of two tumor lines growing at the bottom of transwells was evaluated. cDNA gene expression array, reverse transcription-PCR, and protein expression showed that LPS, transcription termination factor 1, transforming growth factor, and fibroblast growth factor genes were up-modulated by factors other than IFN-gamma released by activated LYS: The high levels of IFN-gamma released by normal IL-12-activated LYs up-modulated the expression of STAT1, IRF-1, LMP2, LMP7, monokine induced by IFN-gamma, monocyte chemoattractant protein 1, and angiopoietin 2 genes but down-modulated the expression of vascular endothelial growth factor. PA28, IFN-inducible protein 10, inducible NO synthetase, and macrophage-inhibitory protein 2 genes were up-modulated by factors released only by IL-12-activated LYs apart from IFN-gamma. The opposite modulations of vascular endothelial growth factor expression and of angiopoietin 2, monokine induced by IFN-gamma, IFN-inducible protein 10, and inducible NO synthetase by IL-12-activated LYs fit in well with the inhibition of angiogenesis that characterizes the antitumor activity of IL-12. T-LYs thus modify a tumor's behavior so that it becomes a party to its own inhibition.

Inhibition of mammary carcinogenesis by systemic interleukin 12 or p185neu DNA vaccination in Her-2/neu transgenic BALB/c mice.

Because BALB/c mice transgenic for the rat Her-2/neu oncogene develop multifocal carcinomas in all mammary glands by week 33, they constitute an aggressive model for investigation of treatments designed to oppose mammary carcinogenesis. Nonspecific immune reaction elicited by systemic interleukin (IL)-12 both delayed the appearance of the first tumor and reduced the number of glands affected. However, only 5% of mice were tumor free at week 33. On the other hand, specific vaccination with plasmids encoding for the rat p185neu resulted in a further delay, so much so that 58% of mice were tumor free at week 33. No CTL response was evoked in either IL-12-treated or DNA-vaccinated mice, whereas an anti-rat p185neu antibody response was evident in the latter. Pathological examinations showed that in both IL-12-treated and DNA-vaccinated mice, the tumor growth area was infiltrated by reactive cells associated with expression of endothelial adhesion molecules and antiangiogenic proinflammatory cytokines. In the vaccinated mice, reduction of the number of cells expressing rat p185neu was combined with down-regulation of its membrane expression and even a marked inhibition in development of the terminal ductal lobular units. The reactive infiltrate in vaccinated mice contained numerous granulocytes that likely played an antiangiogenic and angiodestructive role and also joined other cells in the antibody-mediated killing of the r-p185neu+ cells. These results suggest that the elicitation of nonspecific and specific immunity could be beneficially used in individuals with a high risk of developing tumors.

Therapy of lung metastases through combined vaccination with carcinoma cells engineered to release IL-13 and IFN-gamma.

TS/A spontaneous mouse mammary adenocarcinoma cells were engineered to release interferon-gamma (IFN-gamma), a Th1 cytokine (TS/A-IFNgamma) and interleukin-13 (IL-13), a Th2 cytokine (TS/A-IL13). Mice bearing lung micrometastases induced by parental TS/A cells received repeated subcutaneous vaccinations with TS/A-IFN-gamma admixed with TS/A-IL13 engineered cells. This combined treatment cured up to 75% of mice, whereas vaccinations with either TS/A-IFNgamma or TS/A-IL13 alone cured only 20-40% of mice. Combined TS/A-IL13 and TS/A-IFNgamma therapeutic vaccinations elicited a reactive infiltrate of CD4+ and CD8+ lymphocytes in lung metastases and an increased production of IFN-gamma in the spleen and lung, suggesting a shift of the immune response toward the Th1 type. The type of infiltrating cells along with the lack of efficacy in T cell-deficient mice point to a major role of T cells. In conclusion, no antagonism but a synergistic and effective definitive cure stems from the combined vaccination with tumor cells engineered to release a Th1 and a Th2 cytokine.

Neutrophils in anti-cancer immunological strategies: old players in new games.

This review highlights the new "immunological identity" of neutrophils within the cytokine network and their role in biology of diseases, particularly in tumor biology. The latest preclinical evidence of their involvement in anti-cancer immunotherapeutic and prophylactic strategies will be discussed with particular reference to the real possibilities of transferring experimental results to a clinical setting.

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.