Metastatic colonization involves cancer cell lodgment or adherence in the microvasculature and subsequent migration of those cells across the endothelium into a secondary organ site. To study this process further, we analyzed transendothelial migration of human PC-3 prostate cancer cells in vitro. We isolated a subpopulation of cells, TEM4-18, that crossed an endothelial barrier more efficiently, but surprisingly, were less invasive than parental PC-3 cells in other contexts in vitro. Importantly, TEM4-18 cells were more aggressive than PC-3 cells in a murine metastatic colonization model. Microarray and FACS analysis of these cells showed that the expression of many genes previously associated with leukocyte trafficking and cancer cell extravasation were either unchanged or down-regulated. Instead, TEM4-18 cells exhibited characteristic molecular markers of an epithelial-to-mesenchymal transition (EMT), including frank loss of E-cadherin expression and up-regulation of the E-cadherin repressor ZEB1. Silencing ZEB1 in TEM4-18 cells resulted in increased E-cadherin and reduced transendothelial migration. TEM4-18 cells also express N-cadherin, which was found to be necessary, but not sufficient for increased transendothelial migration. Our results extend the role of EMT in metastasis to transendothelial migration and implicate ZEB1 and N-cadherin in this process in prostate cancer cells. INTRODUCTIONMetastatic prostate cancer is a lethal disease and the second most frequent cause of cancer-related mortality in men in the United States (Jemal et al., 2008). Unfortunately, for such a prevalent disease, much remains unknown about the cellular and molecular mechanisms underlying prostate cancer metastasis. Extravasation, a step within the metastatic cascade, is the process whereby cancer cells exit the circulation via migration through an endothelial monolayer into the parenchyma of a secondary organ site (Wood, 1958). For extravasation to occur, cancer cells, perhaps associated with a thrombus, must first contact the microvascular endothelium, becoming entrapped in small-diameter vessels or adhering specifically to the luminal surface of the endothelium (Warren and Vales, 1972;Kramer and Nicolson, 1979). Some evidence suggests that extravasation is an efficient process, whereas other studies indicate that in some cases it might not occur at all because cancer cells proliferate intraluminally before rupturing microvessels (Crissman et al., 1985;Lapis et al., 1988;Luzzi et al., 1998). Adding to this complexity is that the mechanism of extravasation may depend on the tumor type and vascular bed involved. Thus, as with many other aspects of metastasis, questions remain about the basic mechanisms and the overall role of extravasation in the metastatic cascade.The passage of cancer cells across the endothelium, or transendothelial migration, is thought to be conceptually similar to leukocyte diapedesis (for a recent review see Miles et al., 2008). The extent to which this is true remains controversial, but several classes ...

SUMMARY We used clinical tissue from lethal metastatic castration resistant prostate cancer (CRPC) patients obtained at rapid autopsy to evaluate diverse genomic, transcriptomic, and phosphoproteomic datasets for pathway analysis. Using Tied Diffusion through Interacting Events (TieDIE), we integrated differentially expressed master transcriptional regulators, functionally mutated genes, and differentially activated kinases in CRPC tissues to synthesize a robust signaling network consisting of druggable kinase pathways. Using MSigDB hallmark gene sets, six major signaling pathways with phosphorylation of several key residues were significantly enriched in CRPC tumors after incorporation of phosphoproteomic data. Individual autopsy profiles developed using these hallmarks revealed clinically relevant pathway information potentially suitable for patient stratification and targeted therapies in late stage prostate cancer. Here we describe phosphorylation-based cancer hallmarks using integrated personalized signatures (pCHIPS) that sheds light on the diversity of activated signaling pathways in metastatic CRPC while providing an integrative, pathway-based reference for drug prioritization in individual patients.

SUMMARY Emerging evidence demonstrates that the DNA repair kinase DNA-PKcs exerts divergent roles in transcriptional regulation of unsolved consequence. Here, in vitro and in vivo interrogation demonstrate that DNA-PKcs functions as a selective modulator of transcriptional networks that induce cell migration, invasion, and metastasis. Accordingly, suppression of DNA-PKcs inhibits tumor metastases. Clinical assessment revealed that DNA-PKcs is significantly elevated in advanced disease, and independently predicts for metastases, recurrence, and reduced overall survival. Further investigation demonstrated that DNA-PKcs in advanced tumors is highly activated, independent of DNA damage indicators. Combined, these findings reveal unexpected DNA-PKcs functions, identify DNA-PKcs as a potent driver of tumor progression and metastases, and nominate DNA-PKcs as a therapeutic target for advanced malignancies.

The relationship between the cells that initiate cancer and the cancer stem-like cells that propagate tumors has been poorly defined. In a human prostate tissue transformation model, basal cells expressing the oncogenes Myc and myristoylated AKT can initiate heterogeneous tumors. Tumors contain features of acinartype adenocarcinoma with elevated eIF4E-driven protein translation and squamous cell carcinoma marked by activated betacatenin. Lentiviral integration site analysis revealed that alternative histological phenotypes can be clonally derived from a common cell of origin. In advanced disease, adenocarcinoma can be propagated by self-renewing tumor cells with an androgen receptor-low immature luminal phenotype in the absence of basal-like cells. These data indicate that advanced prostate adenocarcinoma initiated in basal cells can be maintained by luminal-like tumor-propagating cells. Determining the cells that maintain human prostate adenocarcinoma and the signaling pathways characterizing these tumor-propagating cells is critical for developing effective therapeutic strategies against this population.

Moringa oleifera Lam. (M. oleifera), which belongs to the Moringaceae family, is a perennial deciduous tropical tree, and native to the south of the Himalayan Mountains in northern India. M. oleifera is rich in proteins, vitamin A, minerals, essential amino acids, antioxidants, and flavonoids, as well as isothiocyanates. The extracts from M. oleifera exhibit multiple nutraceutical or pharmacological functions including anti-inflammatory, antioxidant, anti-cancer, hepatoprotective, neuroprotective, hypoglycemic, and blood lipid-reducing functions. The beneficial functions of M. oleifera are strongly associated with its phytochemicals such as flavonoids or isothiocyanates with bioactivity. In this review, we summarize the research progress related to the bioactivity and pharmacological mechanisms of M. oleifera in the prevention and treatment of a series of chronic diseases—including inflammatory diseases, neuro-dysfunctional diseases, diabetes, and cancers—which will provide a reference for its potential application in the prevention and treatment of chronic diseases or health promotion.

Dominant mutations or DNA amplification of tyrosine kinases are rare among the oncogenic alterations implicated in prostate cancer. We demonstrate that castration-resistant prostate cancer (CRPC) in men exhibits increased tyrosine phosphorylation, raising the question of whether enhanced tyrosine kinase activity is observed in prostate cancer in the absence of specific tyrosine kinase mutation or DNA amplification. We generated a mouse model of prostate cancer progression using commonly perturbed non-tyrosine kinase oncogenes and pathways and detected a significant up-regulation of tyrosine phosphorylation at the carcinoma stage. Phosphotyrosine peptide enrichment and quantitative mass spectrometry identified oncogene-specific tyrosine kinase signatures, including activation of EGFR, ephrin type-A receptor 2 (EPHA2), and JAK2. Kinase:substrate relationship analysis of the phosphopeptides also revealed ABL1 and SRC tyrosine kinase activation. The observation of elevated tyrosine kinase signaling in advanced prostate cancer and identification of specific tyrosine kinase pathways from genetically defined tumor models point to unique therapeutic approaches using tyrosine kinase inhibitors for advanced prostate cancer.AKT | androgen receptor | ERG | K-RAS | bioinformatics

The cell surface protein Trop2 is expressed on immature stem/progenitor-like cells and is overexpressed in many epithelial cancers. However the biological function of Trop2 in tissue maintenance and tumorigenesis remains unclear. In this study, we demonstrate that Trop2 is a regulator of self-renewal, proliferation, and transformation. Trop2 controls these processes through a mechanism of regulated intramembrane proteolysis that leads to cleavage of Trop2, creating two products: the extracellular domain and the intracellular domain. The intracellular domain of Trop2 is released from the membrane and accumulates in the nucleus. Heightened expression of the Trop2 intracellular domain promotes stem/progenitor self-renewal through signaling via b-catenin and is sufficient to initiate precursor lesions to prostate cancer in vivo. Importantly, we demonstrate that loss of b-catenin or Trop2 loss-of-function cleavage mutants abrogates Trop2-driven self-renewal and hyperplasia in the prostate. These findings suggest that heightened expression of Trop2 is selected for in epithelial cancers to enhance the stem-like properties of self-renewal and proliferation. Defining the mechanism of Trop2 function in self-renewal and transformation is essential to identify new therapeutic strategies to block Trop2 activation in cancer.

Bioluminescence imaging (BLI) has greatly facilitated the development of animal models of cancer, allowing sensitive detection of luciferase-expressing cancer cells in living mice. Previous efforts characterizing such models have involved small numbers of animals, limiting understanding of their performance features. We employed BLI to serially image the growth and distribution of a prostate cancer cell line, 22Rv1, after intracardiac injection into scid mice (n = 85). This approach models hematogenous dissemination of cancer cells and allows inquiry of the process of metastatic colonization at various organ sites, although accurately injecting cancer cells into the left ventricle remains challenging. Therefore, to predict injection success we measured the ratio of the thoracic bioluminescence signal to the whole body bioluminescence signal (T/WB ratio) immediately following intracardiac injection. A T/WB ratio less than 0.50 predicted the development of tumors outside of the thoracic cavity while a T/WB greater than 0.50 predicted the development of tumors entirely within the thoracic cavity, suggestive of a failed injection. Progressive tumor growth was quantified using BLI. Tumors colonized multiple organ sites including bone, liver, and adrenal glands resembling the spectrum of metastases in autopsy studies of patients with prostate cancer. Tumors growing in bone exhibited mixed osteolytic and osteoblastic features, eliciting a spiculated periosteal response. With the ability to more accurately predict injection success, we can now monitor efficacy of intracardiac injections facilitating the performance of this model.