Comparison of expression profiles of metastatic versus primary mammary tumors in MMTV-Wnt-1 and MMTV-Neu transgenic mice

Prune-1 drives polarization of tumor-associated macrophages (TAMs) within the lung metastatic niche in triple-negative breast cancer

M2-tumor-associated macrophages (M2-TAMs) in the tumor microenvironment represent a prognostic indicator for poor outcome in triple-negative breast cancer (TNBC).

Here we show that Prune-1 overexpression in human TNBC patients has positive correlation to lung metastasis and infiltrating M2-TAMs. Thus, we demonstrate that Prune-1 promotes lung metastasis in a genetically engineered mouse model of metastatic TNBC augmenting M2-polarization of TAMs within the tumor microenvironment. Thus, this occurs through TGF-β enhancement, IL-17F secretion, and extracellular vesicle protein content modulation.

We also find murine inactivating gene variants in human TNBC patient cohorts that are involved in activation of the innate immune response, cell adhesion, apoptotic pathways, and DNA repair. Altogether, we indicate that the overexpression of Prune-1, IL-10, COL4A1, ILR1, and PDGFB, together with inactivating mutations of PDE9A, CD244, Sirpb1b, SV140, Iqca1, and PIP5K1B genes, might represent a route of metastatic lung dissemination that need future prognostic validations.

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Prune-1 correlates to M2-TAMs confirming lung metastatic dissemination in GEMM

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Cytokines and EV proteins are responsible of M2-TAMs polarization processes

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A small molecule with immunomodulatory properties ameliorates metastatic dissemination

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Identification of gene variants within immune response and cell adhesion in TNBC

GPNMB augments Wnt-1 mediated breast tumor initiation and growth by enhancing PI3K/AKT/mTOR pathway signaling and β-catenin activity

Glycoprotein Nmb (GPNMB) is overexpressed in triple-negative and basal-like breast cancers and its expression is predictive of poor prognosis within this aggressive breast cancer subtype. GPNMB promotes breast cancer growth, invasion, and metastasis; however, its role in mammary tumor initiation remains unknown. To address this question, we overexpressed GPNMB in the mammary epithelium to generate MMTV/GPNMB transgenic mice and crossed these animals to the MMTV/Wnt-1 mouse model, which is known to recapitulate features of human basal breast cancers. We show that GPNMB alone does not display oncogenic properties; however, its expression dramatically accelerates tumor onset in MMTV/Wnt-1 mice. MMTV/Wnt-1 × MMTV/GPNMB bigenic mice also exhibit a significant increase in the growth rate of established primary tumors, which is attributable to increased proliferation and decreased apoptosis. To elucidate molecular mechanisms underpinning the tumor-promoting effects of GPNMB in this context, we interrogated activated pathways in tumors derived from the MMTV/Wnt-1 and MMTV/Wnt-1 × MMTV/GPNMB mice using RPPA analysis. These data revealed that MMTV/Wnt-1 × MMTV/GPNMB bigenic tumors exhibit a pro-growth signature characterized by elevated PI3K/AKT/mTOR signaling and increased β-catenin activity. Furthermore, we extended these observations to an independent Wnt-1 expressing model of aggressive breast cancer, and confirmed that GPNMB enhances canonical Wnt pathway activation, as evidenced by increased β-catenin transcriptional activity, in breast cancer cells and tumors co-expressing Wnt-1 and GPNMB. GPNMB-dependent engagement of β-catenin occurred, in part, through AKT activation. Taken together, these data ascribe a novel, pro-growth role for GPNMB in Wnt-1 expressing basal breast cancers.

Exosomes isolated from cancer patients' sera transfer malignant traits and confer the same phenotype of primary tumors to oncosuppressor-mutated cells

Background

Horizontal transfer of malignant traits from the primary tumor to distant organs, through blood circulating factors, has recently become a thoroughly studied metastatic pathway to explain cancer dissemination. Recently, we reported that oncosuppressor gene-mutated human cells undergo malignant transformation when exposed to cancer patients’ sera. We also observed that oncosuppressor mutated cells would show an increased uptake of cancer-derived exosomes and we suggested that oncosuppressor genes might protect the integrity of the cell genome by blocking integration of cancer-derived exosomes. In the present study, we tested the hypothesis that cancer patients’ sera-derived exosomes might be responsible for the malignant transformation of target cells and that oncosuppressor mutation would promote their increased uptake. We also sought to unveil the mechanisms behind the hypothesized phenomena.

Methods

We used human BRCA1 knockout (BRCA1-KO) fibroblasts as target cells. Cells were treated in vitro with cancer patients’ sera or cancer patients’ sera-derived exosomes. Treated cells were injected into NOD-SCID mice. Immunohistochemical analyses were performed to determine the differentiation state of the xenotransplants. Mass spectrometry analyses of proteins from cancer exosomes and the BRCA1-KO fibroblasts’ membrane were performed to investigate possible de novo expression of molecules involved in vesicles uptake. Blocking of the identified molecules in vitro was performed and in vivo experiments were conducted to confirm the role of these molecules in the malignant transformation carried out by cancer-derived exosomes.

Results

Cells treated with exosomes isolated from cancer patients’ sera underwent malignant transformation and formed tumors when transplanted into immunodeficient mice. Histological analyses showed that the tumors were carcinomas that differentiated into the same lineage of the primary tumors of blood donors. Oncosuppressor mutation promoted the de novo expression, on the plasma membrane of target cells, of receptors, responsible for the increased uptake of cancer-derived exosomes. The selective blocking of these receptors inhibited the horizontal transfer of malignant traits.

Conclusion

These findings strengthen the hypothesis that oncogenic factors transferred via circulating cancer exosomes, induce malignant transformation of target cells even at distance. Oncosuppressor genes might protect the integrity of the cell genome by inhibiting the uptake of cancer-derived exosomes.

Electronic supplementary material

The online version of this article (10.1186/s13046-017-0587-0) contains supplementary material, which is available to authorized users.

An ovarian mass after breast cancer: Metachronous carcinoma or metastasis? A case report

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In the presence of an ovarian mass after breast cancer, differentiating between primary and secondary lesions can be a difficult task.

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This case report presents a 45-year-old patient with an ovarian mass two years after the diagnosis of breast cancer.

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Imaging, histology and predominantly immunohistochemistry may provide valuable tools in the assessment of ambiguous cases.

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Differences in the immunohistochemical profile of primary tumor and metastases should be anticipated.

Introduction

Differentiating between primary and secondary ovarian cancer can be a difficult task. In hereditary conditions breast malignancies and primary ovarian cancer often coexist.

Presentation of case

We present a 45-year-old patient with an ovarian mass two years after the diagnosis of a lobular, triple negative breast carcinoma. There was concern whether the lesion represented a metachronous ovarian cancer or a metastasis of the lobular carcinoma. The final histological examination showed a metastatic lesion, deriving from the lobular breast carcinoma, as evidenced by the immunohistochemical profile; nevertheless, there were changes in hormonal receptor expression in the metastatic lesion compared to the primary, triple negative tumor. The patient underwent genetic testing for BRCA1 and BRCA2 mutations and was negative. In the adjuvant setting the patient received 6 cycles of chemotherapy with carboplatin and paclitaxel; eighteen months later, the patient remains without disease recurrence.

Discussion and conclusion

This case report highlights the role of imaging, histology and predominantly immunohistochemistry as valuable tools in the assessment of ambiguous ovarian lesions after breast cancer.

Transfer of malignant trait to BRCA1 deficient human fibroblasts following exposure to serum of cancer patients

Background

It was reported that metastases might occur via transfer of biologically active blood circulating molecules from the primary tumor to distant organs rather than only migration of cancer cells. We showed in an earlier study that exposure of immortalized human embryonic kidney cells (HEK 293) to cancer patient sera, induce their transformation into undifferentiated cancers due to a horizontal transfer of malignant traits. In the present work, we tested the hypothesis that even other human cells as long as they are deficient for a single oncosuppressor gene might undergo malignant transformation when exposed to human cancer serum.

Methods

We used the CRISPR/Cas9 system to establish a stable BRCA1 knockout (KO) in human fibroblasts. The BRCA1-KO fibroblasts were exposed to cancer patients’ sera or healthy patients’ sera for 2 weeks. Treated cells were analyzed for cell proliferation and transformation to study their susceptibility to the oncogenic potential of cancer patients’ sera and to determine the possible mechanisms underlying their hypothesized transformation.

Results

BRCA1-KO fibroblasts treated with cancer patients’ sera displayed higher proliferation and underwent malignant transformation as opposed to wild type control fibroblasts, which were not affected by exposure to cancer patients’ sera. The malignant transformation was not seen when BRCA1-KO fibroblasts were treated with healthy human sera. Histological analysis of tumors generated by BRCA1-KO fibroblasts showed that they were carcinomas with phenotypical characteristics related to the cancers of the blood donor patients. Interestingly, BRCA1-KO fibroblasts were significantly more prone to internalize serum-derived exosomes, when compared to wild type fibroblasts. This suggests that oncosuppressor genes might protect the integrity of the cell genome also by blocking integration of cancer-derived exosomes.

Conclusion

These data support the hypothesis that any human cells carrying a single oncosuppressor mutation is capable of integrating cancer factors carried in the blood and undergo complete malignant transformation. Oncosuppressor genes might protect the cell genome by impeding the integration inside the cells of these mutating factors.

Electronic supplementary material

The online version of this article (doi:10.1186/s13046-016-0360-9) contains supplementary material, which is available to authorized users.

The role of Tcfap2c in tumorigenesis and cancer growth in an activated Neu model of mammary carcinogenesis

TFAP2C/AP-2γ influences development of the mammary gland and regulates patterns of gene expression in luminal and HER2-amplified breast cancer. The roles of TFAP2C in mammary gland tumorigenesis and in pathways critical to cancer progression remain poorly understood. To gain greater insight into oncogenic mechanisms regulated by TFAP2C, we examined mammary tumorigenesis in MMTV-Neu transgenic female mice with or without conditional knockout (KO) of Tcfap2c, the mouse homolog of TFAP2C. Loss of Tcfap2c increased the latency of tumorigenesis and tumors that formed demonstrated reduced proliferative index and increased apoptosis. In addition, tumors formed in Tcfap2c KO animals had a significant reduction in Egfr levels without a change in the expression of the Neu oncogene. The MMneu-flAP2C cell line was established from tumor tissue derived from MMTV-Neu/Tcfap2c(L/L) control animals and parallel cell lines with and without expression of Tcfap2c were created by transduction with adenovirus-empty and adenovirus-Cre, respectively. KO of Tcfap2c in vitro reduced activated phosphorylated-Erk, decreased cell viability, repressed tumor growth and was associated with attenuation of Egfr expression. Chromatin immunoprecipitation and direct sequencing and expression analysis confirmed that Egfr was a Tcfap2c target gene in murine, as well as human, mammary carcinoma cells. Furthermore, decreased viability of mammary cancer cells was directly related to Egfr functional blockade. We conclude that TFAP2C regulates tumorigenesis, cell growth and survival in HER2-amplified breast cancer through transcriptional regulation of EGFR. The findings have important implications for targeting the EGFR pathway in breast cancer.

Cripto haploinsufficiency affects in vivo colon tumor development

Colorectal cancer is one of the most common and aggressive cancers arising from alterations in various signaling pathways, such as the WNT, RAS-MAPK, PI3K and transforming growth factor-β (TGF-β) pathways. Cripto (also called Teratocarcinoma-derived growth factor), the original member of the vertebrate EGF-CFC family, plays a key role in all of these pathways and is deeply involved in early embryo development and cancer progression. The role of Cripto in colon and breast cancer, in particular, has been investigated, as it is still not clearly understood. In this article, we provide the first in vivo functional evidence of a role of Cripto in colon cancer development. We analyzed the effect of Cripto haploinsufficiency on colon tumor formation by treating Cripto heterozygous mice with the colonotropic carcinogen azoxymethane (AOM). Of note, in our model system, Cripto haploinsufficiency increased tumorigenesis. Moreover, we revealed a correlation between the differential AOM response found in wt and Cripto⁺/⁻ mice and the expression levels of glucose regulated protein-78 (Grp78), a heat shock protein required for Cripto signaling pathways. We hypothesize that the balance between Cripto and Grp78 expression levels might be crucial in cancer development and may account for the increased tumorigenesis in Cripto heterozygous mice. In summary, our results highlight the heterogeneous effect of Cripto on tumorigenesis and the consequent high level of complexity in the Cripto regulatory pathway, whose imbalance causes tumors.

Bcl3 selectively promotes metastasis of ERBB2-driven mammary tumors

Bcl3 is a putative proto-oncogene deregulated in hematopoietic and solid tumors. Studies in cell lines suggest that its oncogenic effects are mediated through the induction of proliferation and inhibition of cell death, yet its role in endogenous solid tumors has not been established. Here, we address the oncogenic effect of Bcl3 in vivo and describe how this Stat3-responsive oncogene promotes metastasis of ErbB2-positive mammary tumors without affecting primary tumor growth or normal mammary function. Deletion of the Bcl3 gene in ErbB2-positive (MMTV-Neu) mice resulted in a 75% reduction in metastatic tumor burden in the lungs with a 3.6-fold decrease in cell turnover index in these secondary lesions with no significant effect on primary mammary tumor growth, cyclin D1 levels, or caspase-3 activity. Direct inhibition of Bcl3 by siRNA in a transplantation model of an Erbb2-positive mammary tumor cell line confirmed the effect of Bcl3 in malignancy, suggesting that the effect of Bcl3 was intrinsic to the tumor cells. Bcl3 knockdown resulted in a 61% decrease in tumor cell motility and a concomitant increase in the cell migration inhibitors Nme1, Nme2, and Nme3, the GDP dissociation inhibitor Arhgdib, and the metalloprotease inhibitors Timp1 and Timp2. Independent knockdown of Nme1, Nme2, and Arhgdib partially rescued the Bcl3 motility phenotype. These results indicate for the first time a cell-autonomous disease-modifying role for Bcl3 in vivo, affecting metastatic disease progression rather than primary tumor growth.

Dinosaurs and ancient civilizations: reflections on the treatment of cancer

Research efforts in the area of palaeopathology have been seen as an avenue to improve our understanding of the pathogenesis of cancer. Answers to questions of whether dinosaurs had cancer, or if cancer plagued ancient civilizations, have captured the imagination as well as the popular media. Evidence for dinosaurian cancer may indicate that cancer may have been with us from the dawn of time. Ancient recorded history suggests that past civilizations attempted to fight cancer with a variety of interventions. When contemplating the issue why a generalized cure for cancer has not been found, it might prove useful to reflect on the relatively limited time that this issue has been an agenda item of governmental attention as well as continued introduction of an every evolving myriad of manmade carcinogens relative to the total time cancer has been present on planet Earth. This article reflects on the history of cancer and the progress made following the initiation of the "era of cancer chemotherapy."

Surgical injury enhances the expression of genes that mediate breast cancer metastasis to the lung

OBJECTIVE

This study was conducted to test the hypothesis that surgery induces changes at the expression level of genes implicated in metastasis, thus leading to accelerated postoperative metastatic tumor growth.

SUMMARY BACKGROUND DATA

Surgical resection of the primary tumor is a necessary and effective treatment for breast cancer patients. However, studies from both animals and humans have shown that surgery potentiates the growth of minimal residual neoplastic disease.

METHODS

: Female BALB/c mice were inoculated with metastatic murine mammary adenocarcinoma 4T1-green fluorescent protein (GFP) cells in the mammary fat pad (3 × 10⁵/mouse), and divided into a surgery group (n = 12) in which the flank tumor was completely resected after 21 day growth and a control (no surgery) group (n = 12). Metastatic tumor burden was assessed by both macroscopic metastatic nodule count and clonogenic assay. Mitotic and apoptotic indices were established using a combination of hematoxylin-eosin histology and Ki-67 immunohistochemistry. Green fluorescent protein (GFP) expressing tumor cells were isolated using FACS sorting, and RNA was extracted. The RT² Profiler PCR Array mouse Cancer Pathway Finder was used to determine and compare the mRNA levels of 84 genes involved in metastasis in both groups.

RESULTS

Excision of the primary tumor was associated with increased systemic metastatic burden (P = 0.001). Postoperative metastases exhibited increased proliferation (P = 0.001), but no reduction in apoptosis. The quantitative real-time polymerase chain reaction array data indicate that surgery significantly upregulated the expression of Itgb3, Egfr, Hgf, Igf1, Pdgfb, Tnfα, Vegfa, Vegfc, and MMP9 genes, and led to the down regulation of Cdkn2a, Cdh1, and Syk genes. Increased expression of ITGB3 and MMP9 was further confirmed at the protein level by Western blot.

CONCLUSIONS

Removal of the primary tumor led to a progressive phenotype of lung metastases that exhibited upregulation of genes involved in adhesion, invasion, and angiogenesis.

The War on Cancer rages on

In 1971, the "War on Cancer" was launched by the US government to cure cancer by the 200-year anniversary of the founding of the United States of America, 1976. This article briefly looks back at the progress that has been made in cancer research and compares progress made in other areas of human affliction. While progress has indeed been made, the battle continues to rage on.

Lentiviral-mediated transgene expression can potentiate intestinal mesenchymal-epithelial signaling

Mesenchymal-epithelial signaling is essential for the development of many organs and is often disrupted in disease. In this study, we demonstrate the use of lentiviral-mediated transgene delivery as an effective approach for ectopic transgene expression and an alternative to generation of transgenic animals. One benefit to this approach is that it can be used independently or in conjunction with established transgenic or knockout animals for studying modulation of mesenchymal-epithelial interactions. To display the power of this approach, we explored ectopic expression of a Wnt ligand in the mouse intestinal mesenchyme and demonstrate its functional influence on the adjacent epithelium. Our findings highlight the efficient use of lentiviral-mediated transgene expression for modulating mesenchymal-epithelial interactions in vivo.

Neoplasia: the second decade

This issue marks the end of the 10-year anniversary of Neoplasia where we have seen exciting growth in both number of submitted and published articles in Neoplasia. Neoplasia was first published in 1999. During the past 10 years, Neoplasia has dynamically adapted to the needs of the cancer research community as technologies have advanced. Neoplasia is currently providing access to articles through PubMed Central to continue to facilitate rapid broad-based dissemination of published findings to the scientific community through an Open Access model. This has in part helped Neoplasia to achieve an improved impact factor this past year, demonstrating that the manuscripts published by Neoplasia are of great interest to the overall cancer research community. This past year, Neoplasia received a record number of articles for review and has had a 21% increase in the number of published articles.

Sca-1 identifies the tumor-initiating cells in mammary tumors of BALB-neuT transgenic mice

Cancer stem cells, initiating and sustaining the tumor process, have been isolated in human and murine breast cancer using different cell markers. In the present study, we aimed to evaluate the presence and characteristics of stem/tumor-initiating cells in the model of the mouse mammary neoplasia driven by the activated form of rat Her-2/neu oncogene (BALB-neuT mice). For this purpose, we generated tumor spheres from primary spontaneous BALB-neuT tumors. Tumor sphere cultures were characterized for clonogenicity, self-renewal, and ability to differentiate in epithelial/myoepithelial cells of the mammary gland expressing basal and luminal cytokeratins and alpha-smooth muscle actin. In addition, tumor spheres were more resistant to doxorubicin compared with parental tumor cells. In the attempt to identify a selected marker for the sphere-generating cells, we found that Sca-1(+) cells, present in tumors or enriched in mammospheres, and not CD24(+) or CD29(+) cells, were responsible for the sphere generation in vitro. Moreover, cells from the tumor spheres showed an increased tumor-generating ability in respect to the epithelial tumor cells. Sca-1(+) sorted cells or clonal mammospheres derived from a Sca-1(+) cell showed a superimposable tumor-initiating ability. The data of the present study indicate that a Sca-1(+) population derived from mammary BALB-neuT tumors is responsible for sphere generation in culture and for initiating tumors in vivo.

Unlocking the power of cross-species genomic analyses: identification of evolutionarily conserved breast cancer networks and validation of preclinical models

The application of high-throughput genomic technologies has revealed that individual breast tumors display a variety of molecular features that require more personalized approaches to treatment. Several recent studies have demonstrated that a cross-species analytic approach provides a powerful means to filter through genetic complexity by identifying evolutionarily conserved genetic networks that are fundamental to the oncogenic process. Mouse-human tumor comparisons will provide insights into cellular origins of tumor subtypes, define interactive oncogenetic networks, identify potential novel therapeutic targets, and further validate as well as guide the selection of genetically engineered mouse models for preclinical testing.

A case of HER2-positive male breast cancer with lung metastases showing a good response to trastuzumab and paclitaxel treatment

We present a case of advanced HER2-positive male breast cancer, which showed a good response to a combined treatment of trastuzumab and paclitaxel. A 78-year-old man was diagnosed with invasive ductal carcinoma (T4d N3 M1, stage IV). He had advanced breast cancer consisting of multiple tumors with skin involvement and redness over the entire left chest region. A computed tomography (CT) scan of the chest revealed a metastatic tumor in the left lung. Histologically, both the primary breast cancer and the metastatic lung tumor were identified as invasive ductal carcinoma that was estrogen receptor-negative (ER)(-) and progesterone receptor-negative (PgR)(-), with a HER2 score of 3+ (IHC). The patient received a combination chemotherapy using trastuzumab and paclitaxel. Two months later, a follow-up chest CT scan showed that the left lung tumor had disappeared, suggesting a good response to trastuzumab and paclitaxel. During trastuzumab treatment, no severe adverse events above grade 3 were observed. This is the first reported case of advanced HER2-positive male breast cancer in which a good response to trastuzumab and paclitaxel was demonstrated at both primary breast cancer and metastatic sites.