title: Cancer stem cell differentiation: TGFβ1 and versican may trigger molecules for the organization of tumor spheroids.
abstract: Cancer stem cells (CSCs) have the ability to self-renew similar to normal stem cells. This process is linked with metastasis and resistance to chemotherapy and radiotherapy. In the present study, we constructed an in vitro differentiation model for CSCs. CSCs isolated and proliferated for one passage were maintained as monolayers or spheroid-forming cells with serum included media for differentiation process. Differentiation of adhesion molecules and cellular ultrastructural properties were investigated and compared in both monolayer and spheroid cultures. CD133+/CD44+ cancer-initiating cells were isolated from DU-145 human prostate cancer cell line monolayer cultures and propagated as tumor spheroids and compared with the remaining heterogeneous cancer cell bulk population. Microarray-based gene expression analysis was applied to determine genes with differential expression and protein expression levels of candidates were analyzed by immunohistochemistry. Electron microscopy showed detailed analysis of morphology. TGFβ1 was found to be significantly upregulated in monolayer CSCs. High expression levels of VCAN, COL7A1, ITGβ3, MMP16, RPL13A, COL4A2 and TIMP1 and low expression levels of THBS1, MMP1 and MMP14 were detected when CSCs were maintained as serum-grown prostate CSC spheroids. Immunohistochemistry supported increased immunoreactivity of TGFβ1 in monolayer cultures and VCAN in spheroids. CSCs were found to possess multipotential differentiation capabilities through upregulation and/or downregulation of their markers. TGFβ1 is a triggering molecule, it stimulates versican, Col7A1, ITGβ3 and, most importantly, the upregulation of versican was only detected in CSCs. Our data support a model where CSCs must be engaged by one or more signaling cascades to differentiate and initiate tumor formation. This mechanism occurs with intracellular and extracellular signals and it is possible that CSCc themselves may be a source for extracellular signaling. These molecules functioning in tumor progression and differentiation may help develop targeted therapy.
authors.affiliation: Department of Histology and Embryology, Faculty of Medicine, Ege University, Bornova 35100, Izmir, Turkey.
authors.forename: G
authors.initials: G
authors.lastname: Oktem
authors.affiliation: Department of Medical Biology, Faculty of Medicine, Dokuz Eylul University, Narlidere 35340, Izmir, Turkey.
authors.forename: O
authors.initials: O
authors.lastname: Sercan
authors.affiliation: Department of Stem Cell, Ege University Institute of Health Science, Bornova 35100, Izmir, Turkey.
authors.forename: U
authors.initials: U
authors.lastname: Guven
authors.affiliation: Department of Medical Oncology, Faculty of Medicine, Ege University, Bornova 35100, Izmir, Turkey.
authors.forename: R
authors.initials: R
authors.lastname: Uslu
authors.affiliation: Department of Histology and Embryology, Faculty of Medicine, Ege University, Bornova 35100, Izmir, Turkey.
authors.forename: A
authors.initials: A
authors.lastname: Uysal
authors.affiliation: Department of Medical Oncology, Faculty of Medicine, Celal Bayar University, Manisa 45030, Turkey.
authors.forename: G
authors.initials: G
authors.lastname: Goksel
authors.affiliation: Department of Obstetrics and Gynecology, Zeynep Kamil Gynecology and Maternity Training and Research Hospital, Istanbul 34668, Turkey.
authors.forename: S
authors.initials: S
authors.lastname: Ayla
authors.affiliation: Department of Histology and Embryology, Emine-Bahaeddin Nakiboglu Medical Faculty, Zirve University, Gaziantep 27100, Turkey.
authors.forename: A
authors.initials: A
authors.lastname: Bilir
mesh_terms: D000071916:AC133 Antigen; D015703:Antigens, CD / Q000378:metabolism; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism; D002454:Cell Differentiation; D045744:Cell Line, Tumor; D024143:Collagen Type VII / Q000235:genetics / Q000378:metabolism*; D015972:Gene Expression Regulation, Neoplastic; D006023:Glycoproteins / Q000378:metabolism; D006801:Humans; D018960:Hyaluronan Receptors / Q000378:metabolism; D039661:Integrin beta3 / Q000235:genetics / Q000378:metabolism*; D008297:Male; D014411:Neoplastic Stem Cells / Q000378:metabolism*; D010455:Peptides / Q000378:metabolism; D011471:Prostatic Neoplasms / Q000378:metabolism / Q000473:pathology*; D018874:Spheroids, Cellular / Q000378:metabolism*; D053773:Transforming Growth Factor beta1 / Q000235:genetics / Q000378:metabolism*; D053675:Versicans / Q000235:genetics / Q000378:metabolism*
chemical_list: D000071916:AC133 Antigen; D015703:Antigens, CD; D014408:Biomarkers, Tumor; C497483:CD44 protein, human; C569053:COL7A1 protein, human; D024143:Collagen Type VII; D006023:Glycoproteins; D018960:Hyaluronan Receptors; C061248:ITGB3 protein, human; D039661:Integrin beta3; C000606023:PROM1 protein, human; D010455:Peptides; C508960:TGFB1 protein, human; D053773:Transforming Growth Factor beta1; C508322:VCAN protein, human; D053675:Versicans