Dorsomorphin reverses the mesenchymal phenotype of breast cancer initiating cells by inhibition of bone morphogenetic protein signaling

Increasing evidence supports the theory that tumor growth, homeostasis, and recurrence are dependent on a small subset of cells with stem cell properties, redefined cancer initiating cells (CICs) or cancer stem cells. Bone morphogenetic proteins (BMPs) are involved in cell-fate specification during embryogenesis, in the maintenance of developmental potency in adult stem cells and may contribute to sustain CIC populations in breast carcinoma. Using the mouse A17 cell model previously related to mesenchymal cancer stem cells and displaying properties of CICs, we investigated the role of BMPs in the control of breast cancer cell plasticity. We showed that an autocrine activation of BMP signaling is crucial for the maintenance of mesenchymal stem cell phenotype and tumorigenic potential of A17 cells. Pharmacological inhibition of BMP signaling cascade by Dorsomorphin resulted in the acquisition of epithelial-like traits by A17 cells, including expression of Citokeratin-18 and E-cadherin, through downregulation of Snail and Slug transcriptional factors and Cyclooxygenase-2 (COX2) expression, and in the loss of their stem-features and self-renewal ability. This phenotypic switch compromised A17 cell motility, invasiveness and in vitro tumor growth. These results reveal that BMPs are key molecules at the crossroad between stemness and cancer

HER2-Driven Carcinogenesis: New Mouse Models for Novel Immunotherapies

HER2 overexpression is a hallmark of aggressive breast cancer subtypes, and HER2-targeted therapies, such as passive immunotherapy with the humanized monoclonal antibody Trastuzumab, have become standard treatments for these tumor subtypes. However, increasing evidence points to a major role for the Δ16HER2 splice variant, which is commonly coexpressed with the wild-type protein, in cancer progression, metastatic potential and resistance to Trastuzumab treatment. Using our recently derived mouse strain transgenically expressing human Δ16HER2 under the transcriptional control of the MMTV promoter, we showed that this HER2 isoform per se can transform mammary epithelium in vivo. Thus, Δ16HER2 mice provide a new preclinical model in which to study mammary carcinogenesis and the metastatic process, as well as new therapies, including immune-based DNA vaccines. Such vaccines, by virtue of the polyclonal response they induce, might synergize with standard treatments and might ensure targeting of HER2 variants no longer recognized by monoclonal antibodies. In addition, immunological memory might provide long-term anticancer immune protection without side effects associated with many conventional therapies. The efficacy of DNA vaccination against the HER2 oncoantigen has been widely demonstrated in BALB-neuT mice transgenically expressing the activated rat neu oncogene and recapitulating several features of human breast cancers; however, HER2 is a self-tolerated molecule and an effective response to it must circumvent tolerance mechanisms. Here, we retrace the findings that have led to our most promising DNA vaccines encoding human/rat chimeric forms of the HER2 molecule bearing both xenogeneic and syngeneic portions of the protein and able to overcome peripheral tolerance. Preclinical data obtained with our DNA vaccines have provided the rationale for their use in an ongoing phase I clinical trial

Identification of Relevant Conformational Epitopes on the HER2 Oncoprotein by Using Large Fragment Phage Display (LFPD)

We developed a new phage-display based approach, the Large Fragment Phage Display (LFPD), that can be used for mapping conformational epitopes on target molecules of immunological interest. LFPD uses a simplified and more effective phage-display approach in which only a limited set of larger fragments (about 100 aa in length) are expressed on the phage surface. Using the human HER2 oncoprotein as a target, we identified novel B-cell conformational epitopes. The same homologous epitopes were also detected in rat HER2 and all corresponded to the epitopes predicted by computational analysis (PEPITO software), showing that LFPD gives reproducible and accurate results. Interestingly, these newly identified HER2 epitopes seem to be crucial for an effective immune response against HER2-overexpressing breast cancers and might help discriminating between metastatic breast cancer and early breast cancer patients. Overall, the results obtained in this study demonstrated the utility of LFPD and its potential application to the detection of conformational epitopes on many other molecules of interest, as well as, the development of new and potentially more effective B-cell conformational epitopes based vaccines

Inhibition of Asaia in adult mosquitoes causes male-specific mortality and diverse transcriptome changes

Mosquitoes can transmit many infectious diseases, such as malaria, dengue, Zika, yellow fever, and lymphatic filariasis. Current mosquito control strategies are failing to reduce the severity of outbreaks that still cause high human morbidity and mortality worldwide. Great expectations have been placed on genetic control methods. Among other methods, genetic modification of the bacteria colonizing different mosquito species and expressing anti-pathogen molecules may represent an innovative tool to combat mosquito-borne diseases. Nevertheless, this emerging approach, known as paratransgenesis, requires a detailed understanding of the mosquito microbiota and an accurate characterization of selected bacteria candidates. The acetic acid bacteria Asaia is a promising candidate for paratransgenic approaches. We have previously reported that Asaia symbionts play a beneficial role in the normal development of Anopheles mosquito larvae, but no study has yet investigated the role(s) of Asaia in adult mosquito biology. Here we report evidence on how treatment with a highly specific anti-Asaia monoclonal antibody impacts the survival and physiology of adult Anopheles stephensi mosquitoes. Our findings offer useful insight on the role of Asaia in several physiological systems of adult mosquitoes, where the influence differs between males and females

The Human Splice Variant Δ16HER2 Induces Rapid Tumor Onset in a Reporter Transgenic Mouse

Several transgenic mice models solidly support the hypothesis that HER2 (ERBB2) overexpression or mutation promotes tumorigenesis. Recently, a HER2 splice variant lacking exon-16 (Δ16HER2) has been detected in human breast carcinomas. This alternative protein, a normal byproduct of HER2, has an increased transforming potency compared to wild-type (wt) HER2 receptors. To examine the ability of Δ16HER2 to transform mammary epithelium in vivo and to monitor Δ16HER2-driven tumorigenesis in live mice, we generated and characterized a mouse line that transgenically expresses both human Δ16HER2 and firefly luciferase under the transcriptional control of the MMTV promoter. All the transgenic females developed multifocal mammary tumors with a rapid onset and an average latency of 15.11 weeks. Immunohistochemical analysis revealed the concurrent expression of luciferase and the human Δ16HER2 oncogene only in the mammary gland and in strict correlation with tumor development. Transgenic Δ16HER2 expressed on the tumor cell plasma membrane from spontaneous mammary adenocarcinomas formed constitutively active homodimers able to activate the oncogenic signal transduction pathway mediated through Src kinase. These new transgenic animals demonstrate the ability of the human Δ16HER2 isoform to transform “per se” mammary epithelium in vivo. The high tumor incidence as well as the short latency strongly suggests that the Δ16HER2 splice variant represents the transforming form of the HER2 oncoprotein

Sanguinarine anti-tumor activity on a model of basal-like breast cancer

The aim of this work is to study the potential anti-proliferative effects of sanguinarine on mesenchymal cancer basal-like A17 cells isolated from FVB/neuT mammary carcinomas. Studies that have reviewed the histological presentation of basal-like breast cancer demonstrate that >90% of these tumors arise from the breast ducts and are often associated with higher nuclear and histological grade, high mitotic index and more aggressive phenotypic features. This clinical subset represents one of the most important treatment challenges today because these tumors are not likely to respond to hormonal maneuvers (tamoxifen or aromatase inhibitors) nor to drugs targeting HER2 over expression (trastuzumab) [6-17]. Marchini et al compared crucial molecular pathways of A17 derived-carcinoma with that of both carcinomas and other mesenchymal phenotypes, such as mesenchymal stem cells (MSCs), breast stroma, and various types of sarcomas. They identified three mesenchymal/stromal-signatures which A17 cells share with MSCs and breast stroma, showing that these signatures significantly relates to basal-like breast cancer subtypes and significantly relates to bone metastasis [19, 20]. Sanguinarine, a natural benzophenanthridine alkaloid derived from the root of Sanguinaria canadensis and other poppy species, could truly be an excellent candidate as a possible anticancer drug, since many different animals and human cancer cell lines have demonstrated to be highly sensitive to this alkaloid. In this work, sanguinarine shows its efficacy on A17 cell line model, both in in vitro and in in vivo experiments.\ud Mtt, Wound-healing, motility assay and Annexin-V staining revealed that sanguinarine is able to reduce A17 viability, motility, and causes apoptotic and necrotic cell death.\ud Most important, this alkaloid reduces Dihydrofolate Reductase (DHFR) activity, an enzyme implicated in the synthesis of Dna bases.\ud Encouraged by these results, we managed an in vivo experiment by injecting A17 cells in FVB syngenic mice and treating them with sanguinarine: obtained results encouraged us to considered sanguinarine as a promising anticancer drug candidate in the treatment of basal-like breast cancer

The Second Ascoli Piceno Conference on Gene Vacciantion in Cancer, October 9-11 2013

This meeting brings together researchers and clinicians with an interest in gene vaccination in cancer prevention and management and seats them in the center of Italy, in the beautiful city of Ascoli Piceno. The meeting will encourage participants to interact and discuss the pre-clinical and clinical application of gene vaccines

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)

Expression of transient receptor potential vanilloid-1 (TRPV1) in urothelial cancers of human bladder: Relation to clinicopathological and molecular parameters

International audienceAims: The aim of this study was to evaluate the expression of transient receptor potential vanilloid type-1 chennel protein (TRPV1) in normal and tumor urothelial tissues; to correlate TRPV1 expression with clinico-pathological parameters and with disease-specific survival. Methods and Results: TRPV1 expression was analyzed in normal and tumor urothelial samples at both mRNA and protein levels by Real-Time PCR and immunohistochemistry, respectively. TRPV1 down-regulation was found in UC specimens, which correlates with tumor progression. Moreover, TRPV1 mRNA levels were associated to clinico-pathological parameters to asses the role of TRPV1 down-regulation as a negative prognostic factor for survival. Kaplan-Meier survival analysis demonstrated a significantly shorter survival in patients showing TRPV1 mRNA down-regulation. Multivariate Cox regression analysis further indicated that TRPV1 mRNA expression retained its significance as an independent risk factor. Conclusions: The progression of UC of human bladder is associated with a marked decrease of TRPV1 expression, with a progressive loss in high-grade muscle invasive UC. Down-regulation of TRPV1 mRNA expression may represent an independent negative prognostic factor for the survival probability of bladder cancer patients