Evolution of HER2-positive mammary carcinoma: HER2 loss reveals claudin-low traits in cancer progression.

HER2-positive breast cancers may lose HER2 expression in recurrences and metastases. In this work, we studied cell lines derived from two transgenic mammary tumors driven by human HER2 that showed different dynamics of HER2 status. MamBo89HER2 cell line displayed high and stable HER2 expression, which was maintained upon in vivo passages, whereas MamBo43HER2 cell line gave rise to HER2-negative tumors from which MamBo38HER2 cell line was derived.

HER Tyrosine Kinase Family and Rhabdomyosarcoma: Role in Onset and Targeted Therapy.

Rhabdomyosarcomas (RMS) are tumors of the skeletal muscle lineage. Two main features allow for distinction between subtypes: morphology and presence/absence of a translocation between the PAX3 (or PAX7) and FOXO1 genes. The two main subtypes are fusion-positive alveolar RMS (ARMS) and fusion-negative embryonal RMS (ERMS).

Early stability and late random tumor progression of a HER2-positive primary breast cancer patient-derived xenograft.

We established patient-derived xenografts (PDX) from human primary breast cancers and studied whether stability or progressive events occurred during long-term in vivo passages (up to 4 years) in severely immunodeficient mice. While most PDX showed stable biomarker expression and growth phenotype, a HER2-positive PDX (PDX-BRB4) originated a subline (out of 6 studied in parallel) that progressively acquired a significantly increased tumor growth rate, resistance to cell senescence of in vitro cultures, increased stem cell marker expression and high lung metastatic ability, along with a strong decrease of BCL2 expression. RNAseq analysis of the progressed subline showed that BCL2 was connected to three main hub genes also down-regulated (CDKN2A, STAT5A and WT1).

Bioprofiling TS/A Murine Mammary Cancer for a Functional Precision Experimental Model.

The TS/A cell line was established in 1983 from a spontaneous mammary tumor arisen in an inbred BALB/c female mouse. Its features (heterogeneity, low immunogenicity and metastatic ability) rendered the TS/A cell line suitable as a preclinical model for studies on tumor-host interactions and for gene therapy approaches. The integrated biological profile of TS/A resulting from the review of the literature could be a path towards the description of a precision experimental model of mammary cancer.

Cancer Vaccines Co-Targeting HER2/Neu and IGF1R.

(1) Background: Human epidermal growth factor receptor 2 (HER2)/neu-driven carcinogenesis is delayed by preventive vaccines able to elicit autochthonous antibodies against HER2/neu. Since cooperation between different receptor tyrosine kinases (RTKs) can occur in human as well as in experimental tumors, we investigated the set-up of DNA and cell vaccines to elicit an antibody response co-targeting two RTKs: HER2/neu and the Insulin-like Growth Factor Receptor-1 (IGF1R). (2) Methods: Plasmid vectors carrying the murine optimized IGF1R sequence or the human IGF1R isoform were used as electroporated DNA vaccines.

Immune targeting of autocrine IGF2 hampers rhabdomyosarcoma growth and metastasis.

Background: Insulin-like Growth Factor Receptor-1 (IGF1R) system sustains the genesis of rhabdomyosarcoma through IGF2 autocrine overexpression. While several IGF1R-targeted strategies have been investigated to interphere with rhabdomyosarcoma growth, no attempt to neutralize IGF2 has been reported. We therefore studied the possibility to hamper rhabdomyosarcoma growth with passive and active immune approaches targeting IGF2.

OX40 triggering concomitant to IL12-engineered cell vaccine hampers the immunoprevention of HER2/neu-driven mammary carcinogenesis.

This study evaluated the effects of combining an OX40 agonistic antibody (aOX40) with a cell vaccine targeting HER2/neu, called "Triplex". Such HER2/neu cell vaccine included two biological adjuvants (interleukin 12 (IL12) and allogeneic histocompatibility antigens) and was previously found able to prevent autochthonous HER2/neu-driven mammary carcinogenesis. Timing of aOX40 administration, concomitantly or after cell vaccination, gave opposite results.

HER2 isoforms co-expression differently tunes mammary tumor phenotypes affecting onset, vasculature and therapeutic response.

Full-length HER2 oncoprotein and splice variant Delta16 are co-expressed in human breast cancer. We studied their interaction in hybrid transgenic mice bearing human full-length HER2 and Delta16 (F1 HER2/Delta16) in comparison to parental HER2 and Delta16 transgenic mice. Mammary carcinomas onset was faster in F1 HER2/Delta16 and Delta16 than in HER2 mice, however tumor growth was slower, and metastatic spread was comparable in all transgenic mice.

Interleukin-15 is required for immunosurveillance and immunoprevention of HER2/neu-driven mammary carcinogenesis.

Introduction: We previously demonstrated that HER2/neu-driven mammary carcinogenesis can be prevented by an interleukin-12 (IL-12)-adjuvanted allogeneic HER2/neu-expressing cell vaccine. Since IL-12 can induce the release of interleukin-15 (IL-15), in the present study we investigated the role played by IL-15 in HER2/neu driven mammary carcinogenesis and in its immunoprevention.

Methods: HER2/neu transgenic mice with homozygous knockout of IL-15 (here referred to as IL15KO/NeuT mice) were compared to IL-15 wild-type HER2/neu transgenic mice (NeuT) regarding mammary carcinogenesis, profile of peripheral blood lymphocytes and splenocytes and humoral and cellular responses induced by the vaccine.

Genetic prevention of lymphoma in p53 knockout mice allows the early development of p53-related sarcomas.

Homozygous knockout of p53 in mice leads to early mortality from lymphoma, with almost complete penetrance, thus hampering studies of other tumor histotypes related to p53 alterations. To avoid lymphoma development, we crossed p53 knockout mice (BALB-p53 mice) with alymphocytic BALB/c Rag2-/-;Il2rg-/- (RGKO) mice. We compared the tumor spectrum of homozygous (BALB-p53-/-) and heterozygous (BALB-p53+/-) mice with alymphocytic mice (RGKO-p53-/- and RGKO-p53+/-).

Vaccines against human HER2 prevent mammary carcinoma in mice transgenic for human HER2.

Introduction: The availability of mice transgenic for the human HER2 gene (huHER2) and prone to the development of HER2-driven mammary carcinogenesis (referred to as FVB-huHER2 mice) prompted us to study active immunopreventive strategies targeting the human HER2 molecule in a tolerant host.

Methods: FVB-huHER2 mice were vaccinated with either IL-12-adjuvanted human HER2-positive cancer cells or DNA vaccine carrying chimeric human-rat HER2 sequences. Onset and number of mammary tumors were recorded to evaluate vaccine potency.

Tumor suppressor genes promote rhabdomyosarcoma progression in p53 heterozygous, HER-2/neu transgenic mice.

Human sarcomas arise suddenly, thus preempting the study of preneoplastic and early neoplastic lesions. To explore the natural history of these tumors we studied male mice carrying a heterozygous deletion of p53 and an activated HER-2/neu transgene (BALB-p53Neu mice), that develop urethral rhabdomyosarcomas with nearly full penetrance and early onset (4 months of age). Among genes prominently upregulated in preneoplastic tissue, and more highly expressed in tumors, we found the insulin-like growth factor 2 (Igf2) and tumor suppressors, p19Arf and p21Cip1.

Respiratory complex I is essential to induce a Warburg profile in mitochondria-defective tumor cells.

Background: Aerobic glycolysis, namely the Warburg effect, is the main hallmark of cancer cells. Mitochondrial respiratory dysfunction has been proposed to be one of the major causes for such glycolytic shift. This hypothesis has been revisited as tumors appear to undergo waves of gene regulation during progression, some of which rely on functional mitochondria.

Preclinical vaccines against mammary carcinoma.

Vaccines against human breast cancer are an unfulfilled promise. Despite decades of promising preclinical and clinical research, no vaccine is currently available for breast cancer patients. Preclinical research has much to do with this failure, as early mouse models of mammary carcinoma did not mirror the molecular, cellular, antigenic and immunological features of human breast cancer.

Different mtDNA mutations modify tumor progression in dependence of the degree of respiratory complex I impairment.

Mitochondrial DNA mutations are currently investigated as modifying factors impinging on tumor growth and aggressiveness, having been found in virtually all cancer types and most commonly affecting genes encoding mitochondrial complex I (CI) subunits. However, it is still unclear whether they exert a pro- or anti-tumorigenic effect. We here analyzed the impact of three homoplasmic mtDNA mutations (m.

Preclinical HER-2 Vaccines: From Rodent to Human HER-2.

Effective prevention of human cancer with vaccines against viruses, such as HBV and HPV, raises the question whether also non-virus related tumors could be prevented with immunological means. Studies in HER-2-transgenic mice showed that powerful anti-HER-2 vaccines, could almost completely prevent the onset of mammary carcinoma. Protective immune responses were orchestrated by T cells and their cytokines, and effected by antibodies against HER-2 gene product p185.

Preclinical therapy of disseminated HER-2⁺ ovarian and breast carcinomas with a HER-2-retargeted oncolytic herpesvirus.

Oncolytic viruses aim to specifically kill tumor cells. A major challenge is the effective targeting of disseminated tumors in vivo. We retargeted herpes simplex virus (HSV) tropism to HER-2 oncoprotein p185, overexpressed in ovary and breast cancers.

Multiorgan metastasis of human HER-2+ breast cancer in Rag2-/-;Il2rg-/- mice and treatment with PI3K inhibitor.

In vivo studies of the metastatic process are severely hampered by the fact that most human tumor cell lines derived from highly metastatic tumors fail to consistently metastasize in immunodeficient mice like nude mice. We describe a model system based on a highly immunodeficient double knockout mouse, Rag2-/-;Il2rg-/-, which lacks T, B and NK cell activity. In this model human metastatic HER-2+ breast cancer cells displayed their full multiorgan metastatic potential, without the need for selections or additional manipulations of the system.

A mutation threshold distinguishes the antitumorigenic effects of the mitochondrial gene MTND1, an oncojanus function.

The oncogenic versus suppressor roles of mitochondrial genes have long been debated. Peculiar features of mitochondrial genetics such as hetero/homoplasmy and mutation threshold are seldom taken into account in this debate. Mitochondrial DNA (mtDNA) mutations generally have been claimed to be protumorigenic, but they are also hallmarks of mostly benign oncocytic tumors wherein they help reduce adaptation to hypoxia by destabilizing hypoxia-inducible factor-1α (HIF1α).

The molecular basis of herpesviruses as oncolytic agents.

Herpes simplex viruses (HSVs) have entered clinical trials as oncolytic agents. The following properties make them good candidates. It is a mild pathogen; drugs (Aciclovir) are available to control viral infection; the large genome is amenable to genetic engineering, they can be rendered cancer-specific by deletion of genes, envelope glycoproteins allow the insertion of heterologous ligands to achieve modification of the natural tropism.

Rethinking herpes simplex virus: the way to oncolytic agents.

Oncolytic viruses infect, replicate in and kill cancer cells. HSV has emerged as a most promising candidate because it exerts a generally moderate pathogenicity in humans; it is amenable to attenuation and tropism retargeting; the ample genome provides space for heterologous genes; specific antiviral therapy is available in a worst case scenario. The first strategy to convert HSV into an oncolytic agent consisted in deletion of the γ(1) 34.

HER-2/neu tolerant and non-tolerant mice for fine assessment of antimetastatic potency of dendritic cell-tumor cell hybrid vaccines.

Main obstacles to cancer vaccine efficacy are pre-existing antigenic load and immunoescape mechanisms, including tolerance against self tumor-associated antigens. Here we explored the role of tolerance in an antimetastatic vaccine approach based on dendritic cell-tumor cell (DC-TC) hybrids, thanks to the comparison between BALB-neuT mice, transgenic for and tolerant to rat HER-2/neu, with their non-tolerant strain of origin BALB/c. Allogeneic DC-TC hybrid vaccine displayed a high antimetastatic activity in non-tolerant mice, but was far less effective in tolerant mice, even with intensified vaccine schedule.

2011: the immune hallmarks of cancer.

Ten years after the publication of the position paper "The hallmarks of cancer" (Hanahan and Weinberg Cell 100:57-70, 2000), it has become increasingly clear that mutated cells on their way to giving rise to a tumor have also to learn how to thrive in a chronically inflamed microenvironment, evade immune recognition, and suppress immune reactivity. Genetic and molecular definition of these three immune hallmarks of cancer offers the opportunity to learn how to deploy specific countermeasures to reverse the situation in favor of the immune system and, eventually, the patient. This new information could be channeled to address what seem to be the three major hallmarks for the immune control of cancer progression: effective procedures to activate immune reactivity; characterization of not-disposable oncoantigens; and counteraction of immune suppression.

Vaccines and other immunological approaches for cancer immunoprevention.

The immune system effectively prevents cancer, whereas severe immunodepression increases its incidence. Cancer immunoprevention is a strategy based on the concept that enhancement of tumor immunity in healthy individuals reduces cancer risk. It can be viewed as a kind of chemoprevention.

Immunoprevention and immunotherapy of mammary carcinoma.

Cancer immunoprevention posits that the enhancement of immune defenses in healthy individuals could control tumor onset. Immunoprevention of viral tumors is already implemented at the population level for human hepatocellular and cervical carcinomas. Altogether, viral vaccines could prevent more than 10% of all human tumors.