Semination termed amoeboid motility.2,3 Amoeboid cells are less dependent on pericellular proteolysis, exhibit loss of cell polarity, readily deform their shape through cytoskeletal remodeling, and can migrate rapidly through complex matrices.4,*Correspondence to: Michael Freeman; Email: [email protected] Submitted: 09/20/2013; Revised: 12/04/2013; Accepted: 12/22/2013 http://dx.doi.org/10.4161/cbt.27627 www.landesbioscienceDue to heightened actomyosin contractility, amoeboid cells display rounded morphologies and prominent bleb-like protrusions.3,6-9 Our laboratory previously demonstrated that certain amoeboid cells shed large extracellular vesicles (EV), in the size range of 0.50 m in diameter, into the extracellular space.10 Like nano-sized exosomes (generally 100 nm), these large EV, termed “large oncosomes”, harbor abundant biomolecules and are bioactive.10 Large oncosomes are among several types of EV shed from tumor cells,11 of which exosomes have been the most extensively characterized.12 Tumor-derived EV can be enriched in nucleic acids, including DNA, mRNA, miRNA, and small non-coding RNAs, as well as oncoproteins and metabolites, and can thereby mediate the horizontal transfer of oncogenic information to neighboring cells.12 We and others have demonstrated that the interaction of EV with recipient cells is associated withcancer Biology Therapy014 Landes Bioscience. Do not distribute.ResultsEV shedding from LNCaP cells is enhanced by ERK1/2 activation We previously reported that heparin-binding EGF-like growth factor (HB-EGF), a product of smooth muscle cells in the prostate stroma, plays a role as a paracrine regulator of prostate tumor cells.24 HB-EGF activates EGFR and ERK1/2 signaling,25 alters proliferation and apoptosis induced by H2O2 or etoposide treatment,26 and promotes an aggressive, neuroendocrine phenotype in prostate cancer cells.Bulevirtide 25 We also observed that HB-EGF enhances shedding of EV in the size range of large oncosomes.23 To test whether HB-EGF might also increase shedding of exosome-sized (100 nm) EV, LNCaP cells, which exhibit low basal EV formation,23 were transfected with a constitutively secreted HB-EGF construct (sHB-EGF) or control vector. Immunoblotting confirmed HB-EGF secretion into the conditioned medium (CM),cancer Biology TherapyVolume 15 Issue014 Landes Bioscience. Do not distribute.stromal activation,10 promotion of tumor cell invasion,10 endothelial cell migration and angiogenesis,13,14 modulation of inflammatory responses,15 and enhanced drug resistance.Cariprazine hydrochloride 16 EV preserve the bioactivity of their molecular cargo and can be readily isolated from multiple biological fluids (e.PMID:23800738 g., urine, serum, plasma, pleural effusion, and saliva), suggesting that these particles may constitute a potential source of biomarkers for real-time assessments of cancer progression.17 Our laboratory recently identified Diaphanous-related formin-3 (DIAPH3) as a non-canonical metastasis suppressor.18 DIAPH3 belongs to a family of formin orthologs that share tandem FH1 and FH2 domains and regulate cytoskeletal dynamics.19 Formins nucleate, elongate, and bundle linear actin filaments and stabilize microtubules, and have been implicated in endocytosis, cell division, and migration.20-22 We observed that genomic loss at the DIAPH3 locus is strongly associated with metastatic disease in human prostate cancer, breast cancer, and hepatocellular carcinoma.18 Furthermore, silencing of DIAPH3 by RNAi induced a morphological t.
