The epidermal specific ablation of Trp53 gene leads to the spontaneous development of aggressive tumors in mice through a process that is accelerated by the simultaneous ablation of Rb gene. Since alterations of p53-dependent pathway are common hallmarks of aggressive, poor prognostic human cancers, these mouse models can recapitulate the molecular features of some of these human malignancies. To evaluate this possibility, gene expression microarray analysis was performed in mouse samples. The mouse tumors display increased expression of cell cycle and chromosomal instability associated genes. Remarkably, they are also enriched in human embryonic stem cell gene signatures, a characteristic feature of human aggressive tumors. Using cross-species comparison and meta-analytical approaches, we also observed that spontaneous mouse tumors display robust similarities with gene expression profiles of human tumors bearing mutated TP53, or displaying poor prognostic outcome, from multiple body tissues. We have obtained a 20-gene signature whose genes are overexpressed in mouse tumors and can identify human tumors with poor outcome from breast cancer, astrocytoma and multiple myeloma. This signature was consistently overexpressed in additional mouse tumors using microarray analysis. Two of the genes of this signature, AURKA and UBE2C, were validated in human breast and cervical cancer as potential biomarkers of malignancy. Our analyses demonstrate that these mouse models are promising preclinical tools aimed to search for malignancy biomarkers and to test targeted therapies of prospective use in human aggressive tumors and/or with p53 mutation or inactivation.
Gene expression profiling of mouse p53-deficient epidermal carcinoma defines molecular determinants of human cancer malignancy.
Age, Specimen part
View SamplesThe specific ablation of Rb1 gene in stratified epithelia (RbF/F;K14cre) promotes proliferation and altered differentiation but is insufficient to produce spontaneous tumors. The pRb relative, p107, compensates some of the functions of pRb in these tissues, however RbF/F;K14cre;p107-/- mice die postnatally. Acute pRb loss in stratified epithelia, using an inducible mouse model (RbF/F;K14creERTM), shows that p107 exerts specific tumor suppressor functions in its absence. After simultaneous absence of pRb and p107, p53 transcriptional function is impaired and Pten expression is reduced. All mutant mice develop spontaneous squamous tumors carcinomas rapidly. Gene expression analysis of mouse tumors, besides supporting the impaired p53 function and the susceptibility to Akt/mTOR inhibitors, also revealed significant overlap with human squamous carcinomas. Thus, RbF/F;K14creERTM;p107-/- may constitute a new mouse model for these malignancies. Collectively, these data demonstrate the existence of a previously unreported functional connection between pRb, Pten and p53 tumor suppressors, through p107, of a particular relevance in squamous tumor development.
A novel tumor suppressor network in squamous malignancies.
Specimen part
View SamplesA permantly active form of the oncogene Akt was expressed in the keratinocytes of the basal proliferative layer of the epidermis. Stem cells of the hair follicle expressing the cell surface marker CD34 were isolated. RNA form the CD34(+) and CD34(-) keratinocytes was extracted and and hybridized to Mouse Genome 430 2.0 Affymetrix arrays.
Akt signaling leads to stem cell activation and promotes tumor development in epidermis.
Specimen part
View SamplesBackground: Gq-coupled G protein-coupled receptors (GPCR) mediate the actions of a variety of messengers that are key regulators of cardiovascular function. Enhanced Gaq-mediated signaling plays an important role in cardiac hypertrophy and in the transition to heart failure. We have recently described that Gaq acts as an adaptor protein that facilitates PKCz-mediated activation of ERK5 in epithelial cells. Since the ERK5 cascade is known to be involved in cardiac hypertrophy, we have investigated the potential relevance of this pathway in Gq-dependent signaling in cardiac cells.
Protein kinase C (PKC)ζ-mediated Gαq stimulation of ERK5 protein pathway in cardiomyocytes and cardiac fibroblasts.
Sex, Age, Specimen part
View SamplesIKKbeta is a subunit of the IkB kinase (IKK) complex required for NF-kB activation in response to pro-inflammatory signals. NF-kB regulates the expression of many genes involved in inflammation, immunity and apoptosis, and also controls cell proliferation and differentiation in different tissues; however, its function in skin physiopathology remains controversial. We here report the alterations caused by increased IKKbeta activity in basal cells of the skin of transgenic mice.
IKKbeta leads to an inflammatory skin disease resembling interface dermatitis.
Sex, Age, Specimen part
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