Cumulative observations by our group led us to hypothesize that the molecular processes by which p53 and p63 regulate urothelial differentiation are causally linked to their role in bladder tumor initiation and progression. Our main objective is to define the critical functions of p53 and p63-isoforms in urothelial development, bladder cancer initiation and progression. For this purpose, we will use state-of -the- art molecular pathology and genetic approaches utilizing in vitro cell-based assays and in vivo mouse models, validating significant findings in human normal and tumor bladder tissues.
The specific aims are:
Aim #1. Comprehensive analysis of p53 and p63-isoforms during urothelial development. We discovered that p63 is essential for urothelial differentiation, and that p63-null mice developed an abnormal mono-cellular layer urothelium. Preliminary data supports that this layer is constituted of "umbrella" cells.
This aim has two subaims: 1A) To further define the p63 dependent pathway of urothelial differentiation (basal &suprabasal layers) vs. p63 Independent pathway (umbrella cells). We will define gene expression profiles of microdissected cell types of murine and human urothelium. p53 and p63 functional status will be assessed in distinct urothelial cells, and in recently identified candidate urothelial progrenitor/stem cell. 1B) To model urothelial development in the mouse using RNAi models. We are generating transgenic mice targeting TA and DeltaN p63-isoforms using a novel shRNA conditional approach. This will allow analysis of how suppression of p63 variants affects urothelial development, and their impact on the adult urothelium.
Aim #2. Molecular and functional studies of p53 and p63-isoforms in bladder cancer progression. We will correlate TP53 mutational status and p63-isoform expression in non-invasive and invasive bladder carcinomas, deciphering the biological activities of these p53-family members in bladder cancer. Recent data from our laboratory reveals that mutant p53 and p63 DeltaN display negative cooperative effects, and that invasive bladder cancer could be categorized into two subgroups based on p63-isoforms expression. This phenomenon will be mechanistically explored using in vitro approaches.
Aim #3. Role of p53 and p63-isoforms in bladder cancer stem cells and the resistance phenotype. We plan to further characterize a candidate bladder cancer stem cell that we recently identified using gene/protein expression analyses. Our studies will center on defining the functional significance of p53 and p63-isoforms in bladder cancer stem cell homeostasis. We will evaluate the clinical relevance of the identified cancer stem cell by performing quantitative analysis of its "cell load" as it relates to chemoresistance, and by testing novel therapeutic compounds targeting this cancer stem cell population.
Understanding critical processes regulated by p53 family members implicated in urothelial development and bladder tumor initiation will enhance our search for urothelial stem cells and related bladder cancer stem cells. Our studies have significant translational implications through the definition of a novel urothelial histogenesis model based on p63-differentiation pathways, determining and validating the predictive nature of p53 and p63 alterations in bladder cancer, and identifying candidate bladder cancer stem cells. In sum, results from these studies will have far reaching implications regarding bladder cancer prognosis and establishing effective treatment, thus assisting in the implementation of personalized patient care.
|Miething, Cornelius; Scuoppo, Claudio; Bosbach, Benedikt et al. (2014) PTEN action in leukaemia dictated by the tissue microenvironment. Nature 510:402-6|
|Jia, A Y; Castillo-Martin, M; Bonal, D M et al. (2014) MicroRNA-126 inhibits invasion in bladder cancer via regulation of ADAM9. Br J Cancer 110:2945-54|
|Barber, Alison G; Castillo-Martin, Mireia; Bonal, Dennis M et al. (2014) Characterization of desmoglein expression in the normal prostatic gland. Desmoglein 2 is an independent prognostic factor for aggressive prostate cancer. PLoS One 9:e98786|
|Chen, Chong; Liu, Yu; Rappaport, Amy R et al. (2014) MLL3 is a haploinsufficient 7q tumor suppressor in acute myeloid leukemia. Cancer Cell 25:652-65|
|Jia, Angela Y; Castillo-Martin, Mireia; Domingo-Domenech, Josep et al. (2013) A common MicroRNA signature consisting of miR-133a, miR-139-3p, and miR-142-3p clusters bladder carcinoma in situ with normal umbrella cells. Am J Pathol 182:1171-9|
|Mills, John R; Malina, Abba; Lee, Teresa et al. (2013) RNAi screening uncovers Dhx9 as a modifier of ABT-737 resistance in an E?-myc/Bcl-2 mouse model. Blood 121:3402-12|
|Freed-Pastor, William A; Mizuno, Hideaki; Zhao, Xi et al. (2012) Mutant p53 disrupts mammary tissue architecture via the mevalonate pathway. Cell 148:244-58|
|Shen, Tian Huai; Gladoun, Nataliya; Castillo-Martin, Mireia et al. (2012) A BAC-based transgenic mouse specifically expresses an inducible Cre in the urothelium. PLoS One 7:e35243|
|Karni-Schmidt, Orit; Castillo-Martin, Mireia; Shen, Tian Huai et al. (2011) Distinct expression profiles of p63 variants during urothelial development and bladder cancer progression. Am J Pathol 178:1350-60|
|Wosnitzer, Matthew S; Domingo-Domenech, Josep; Castillo-Martin, Mireia et al. (2011) Predictive value of microtubule associated proteins tau and stathmin in patients with nonmuscle invasive bladder cancer receiving adjuvant intravesical taxane therapy. J Urol 186:2094-100|
Showing the most recent 10 out of 68 publications