RT Journal Article SR Electronic T1 Enhanced regulation of cell cycle and suppression of osteoblast differentiation molecular signatures by prostate cancer stem-like holoclones JF Journal of Clinical Pathology JO J Clin Pathol FD BMJ Publishing Group Ltd and Association of Clinical Pathologists SP 692 OP 702 DO 10.1136/jclinpath-2015-203001 VO 68 IS 9 A1 Gallagher, Michael F A1 Salley, Yvonne A1 Spillane, Cathy D A1 Ffrench, Brendan A1 El Baruni, Salah A1 Blacksheilds, Gordon A1 Smyth, Paul A1 Martin, Cara A1 Sheils, Orla A1 Watson, William A1 O'Leary, John J YR 2015 UL http://jcp.bmj.com/content/68/9/692.abstract AB Aims Targeting the stem cell properties of tumor-initiating cells is an avenue through which cancer treatment may be improved. Before this can be achieved, so-called ‘cancer stem cell’ (CSC) models must be developed and characterized in specific malignancies.Methods In this study, holoclone formation assays were used to characterise stem-like molecular signatures in prostate cancer (PCa) cells.Results LNCaP and PC3 parent cells were capable of responding to stem cell differentiation morphogen retinoic acid (RA), suggesting the presence of inherent stem-like properties. LNCaP cells, which represent early, androgen-responsive disease, formed holoclones after twenty six days. PC3 cells, which represent advanced, metastatic, castration-resistant disease, formed holoclones after only six days. Holoclones displayed decreased expression of RA-genes, suggesting a more immature, less differentiated phenotype. Gene and microRNA arrays demonstrated that holoclones downregulated a number of stem cell differentiation regulators while displaying enhanced regulation of G2 to M transition and the mitotic spindle checkpoint components of the cell cycle. PC3 holoclones displayed pronounced downregulation of known regulators of osteoblast differentiation from mesenchymal stem cells and Epithelial Mesenchymal Transition.Conclusions Our results suggest that some PCa cells retain the ability to transition to a more immature state in which differentiation and metastatic mechanisms are suppressed. The highlighting of osteoblast differentiation regulators in this mechanism is particularly notable, considering the propensity of PCa to metastasise to bone.