S U M M A R Y Primary cilia (PC) are solitary, sensory organelles that are critical for several signaling pathways. PC were detected by immunofluorescence of cultured cells and breast tissues. After growth for 7 days in vitro, PC were detected in ?70% of breast fibroblasts and in 7-19% of epithelial cells derived from benign breast (184A1 and MCF10A). In 11 breast cancer cell lines, PC were present at a low frequency in four (from 0.3% to 4% of cells), but were absent in the remainder. The cancer cell lines with PC were all of the basal B subtype, which is analogous to the clinical triple-negative breast cancer subtype. Furthermore, the frequency of PC decreased with increasing degree of transformation/progression in the MCF10 and MDA-MB-435/LCC6 isogenic models of cancer progression. In histologically normal breast tissues, PC were frequent in fibroblasts and myoepithelial cells and less common in luminal epithelial cells. Of 26 breast cancers examined, rare PC were identified in cancer epithelial cells of only one cancer, which was of the triple-negative subtype. These data indicate a decrease or loss of PC in breast cancer and an association of PC with the basal B subtype. This manuscript contains online supplemental material at http://www.jhc.org. Please visit this article online to view these materials. (J Histochem Cytochem 58:857-870, 2010)

Bone metastasis will impact most men with advanced prostate cancer. The vicious cycle of bone degradation and formation driven by metastatic prostate cells in bone yields factors that drive cancer growth. Mechanistic insights into this vicious cycle have suggested new therapeutic opportunities, but complex temporal and cellular interactions in the bone microenvironment make drug development challenging. We have integrated biological and computational approaches to generate a hybrid cellular automata (HCA) model of normal bone matrix homeostasis and the prostate cancer-bone microenvironment. The model accurately reproduces the basic multicellular unit (BMU) bone coupling process, such that introduction of a single prostate cancer cell yields a vicious cycle similar in cellular composition and pathophysiology to models of prostate-to-bone metastasis. Notably, the model revealed distinct phases of osteolytic and osteogenic activity; a critical role for mesenchymal stromal cells (MSCs) in osteogenesis; and temporal changes in cellular composition. To evaluate the robustness of the model is we assessed the effect of established bisphosphonate and anti-RANKL therapies on bone metastases. At ~100% efficacy, bisphosphonates inhibited cancer progression while, in contrast to clinical observations in humans, anti-RANKL therapy fully eradicated metastases. Reducing anti-RANKL yielded clinically similar results, suggesting that better targeting or dosing could improve patient survival. Our work establishes a computational model that can be tailored for rapid assessment of experimental therapies and delivery of precision medicine to prostate cancer patients with bone metastases.

Background Chemoprevention utilizing dietary agents is an effective means to slow the development of prostate cancer. We evaluated the potential additive and synergistic effects of genistein and resveratrol for suppressing prostate cancer in the Simian Virus-40 T-antigen (SV-40 Tag) targeted probasin promoter rat model, a transgenic model of spontaneously developing prostate cancer. Methods Rats were fed genistein or resveratrol (250 mg/kg AIN-76A diet) alone and in combination, and a low dose combination (83 mg genistein + 83 mg resveratrol/kg diet). Histopathology and mechanisms of action studies were conducted at 30 and 12 weeks of age, respectively. Results Genistein, resveratrol, and the high dose combination treatments suppressed prostate cancer. The low dose combination did not elicit protection against prostate cancer and was most likely below the effective dose for causing significant histopathological changes. Total genistein and resveratrol concentrations in the blood reached 2160 and 211 nM, respectively in rats exposed to the single treatments. Polyphenol treatments decreased cell proliferation and insulin-like growth factor-1 (IGF-1) protein expression in the prostate. In addition, genistein as a single agent induced apoptosis and decreased steroid receptor coactivator-3 (SRC-3) in the ventral prostate (VP). Conclusions Genistein and resveratrol, alone and in combination, suppress prostate cancer development in the SV-40 Tag model. Regulation of SRC-3 and growth factor signaling proteins are consistent with these nutritional polyphenols reducing cell proliferation and increasing apoptosis in the prostate.

Plakoglobin (c-catenin) is a homolog of b-catenin with similar dual adhesive and signaling functions. The adhesive function of these proteins is mediated by their interactions with cadherins, whereas their signaling activity is regulated by association with various intracellular partners. In this respect, b-catenin has a well-defined oncogenic activity through its role in the Wnt signaling pathway, whereas plakoglobin acts as a tumor/metastasis suppressor through mechanisms that remain unclear. We previously expressed plakoglobin in SCC9 squamous carcinoma cells (SCC9-P) and observed a mesenchymalto-epidermoid transition. Comparison of the protein and RNA profiles of parental SCC9 cells and SCC9-P transfectants identified various differentially expressed proteins and transcripts, including the nonmetastatic protein 23 (Nm23). In this study, we show that Nm23-H1 mRNA and Nm23-H2 protein are increased after plakoglobin expression. Coimmunoprecipitation and confocal microscopy studies using SCC9-P and various epithelial cell lines with endogenous plakoglobin expression revealed that Nm23 interacts with plakoglobin, cadherins and a-catenin. Furthermore, Nm23-H2 is the primary isoform involved in these interactions, which occur prominently in the cytoskeleton-associated pool of cellular proteins. In addition, we show that plakoglobinNm23 interaction requires the N-terminal (a-catenin interacting) domain of plakoglobin. Our data suggest that by increasing the expression and stability of Nm23, plakoglobin has a role in regulating the metastasis suppressor activity of Nm23, which may further provide a potential mechanism for the tumor/metastasis suppressor function of plakoglobin itself.

Summary In prostate to bone metastases, the “vicious cycle” paradigm has been traditionally used to illustrate how metastases manipulate the bone forming osteoblasts and resorbing osteoclasts in order to yield factors that facilitate the growth and establishment. However, recent advances have illustrated that the cycle is far more complex than this simple interpretation. In this review, we will discuss the role of exosomes and hematopoietic/mesenchymal stem cells facilitate the establishment and activation of prostate metastases and, how cells including such as myeloid derived suppressor cells, macrophages, T-cells and nerve cells contribute to the momentum of the vicious cycle. The increased complexity of the tumor-bone microenvironment requires a systems level approach. The evolution of computational models to interrogate the tumor-bone microenvironment is also discussed and the application of this integrated approach should allow for the development of effective therapies to treat and cure prostate to bone metastases.