Browsing by Author "Guven, U"

Now showing 1 - 4 of 4
  • No Thumbnail Available
    Item
  • No Thumbnail Available
    Item
    WNT1 gene expression alters in heterogeneous population of prostate cancer cells; decreased expression pattern observed in CD133+/CD44+ prostate cancer stem cell spheroids
    Goksel, G; Bilir, A; Uslu, R; Akbulut, H; Guven, U; Oktem, G
    Purpose: Established cancer cell lines contain cancer stem cells (CSCs) which can propagate to form three dimensional (3D) tumor spheroids in vitro. Aberrant activation of WNT signaling is strongly implicated in the progression of cancer and controls CSCs properties. In this study we hypothesized that when cells were maintained as spheroids, the structure of CSCs could show differentiation between CSCs and non-CSCs. Methods: CD133(+)/CD44(+) cancer-initiating cells were isolated from DU-145 human prostate cancer cell line monolayer cultures, propagated as tumor spheroids and compared with the remaining heterogeneous cancer cells bulk population. The expression levels of WNT1, FZD1, ADAR, APC, AXIN, BTRC, FRAT1 and PPARD genes were measured by polymerase chain reaction (PCR) array assay and the protein expression levels of WNT1, FZD and AXIN by immunohistochemistry. Results: The expression levels of WNT pathway-related molecules were found to increase in both CSCs and non-CSCs when CSCs were maintained as spheroids. However, different expression profiles were observed when CSCs and non-CSCs were compared. In spheroids, the expression levels of FZD1, APC, ADAR, WNT1, PPARD genes in CSCs decreased when compared to non-CSCs. Interestingly, when CSCs from spheroids were compared with CSCs from monolayers the most significant decrease was observed in FZD1 and increase in APC genes. Conclusion: It is possible to assume that intracellular signaling of WNT-related molecules in the nucleus and/or cytoplasm might play an important role but it is independent from increased ligand expression and this expression strongly differentiate CSCs and non-CSCs population. This unexpected expression could be important for CSCs behavior and targeting this pathway could have therapeutic implications in cancer.
  • No Thumbnail Available
    Item
    JAK/STAT pathway interacts with intercellular cell adhesion molecule (ICAM) and vascular cell adhesion molecule (VCAM) while prostate cancer stem cells form tumor spheroids
    Duzagac, F; Inan, S; Simsek, FE; Acikgoz, E; Guven, U; Khan, SA; Rouhrazi, H; Oltulu, F; Aktug, H; Erol, A; Oktem, G
    Purpose: JAK/STAT is an evolutionarily conserved pathway and very important for second messenger system. This pathway is important in malignant transformation and accumulated evidence indicates that this pathway is involved in tumorigenesis and progression of several cancers. It was possible to assume that activation of JAK/STAT pathway is associated with increase in the expressions of ICAM-1 and VCAM-1. In this study we hypothesized that when cells were maintained as spheroids or monolayers, the structure of cancer stem cells (CSCs) could show differentiation when compared with non-CSCs. Methods: DU-145 human prostate cancer cells were cultured using the Ege University molecular embryology laboratory medium supplemented with 10% fetal bovine serum. Clusters of differentiation 133 (CD133)(+high)/ CD44(+high) prostate CSCs were isolated from the DU145 cell line by using BD FACSAria. CD133(+)/CD44(+) CSCs were cultured until confluent with 3% noble agar. The expression of these proteins in CSCs and non-CSCs was analyzed by immunohistochemistry. Results : Different expression profiles were observed in the conventional two-dimensional (2D) and three-dimensional (3D) experimental model system when CSCs and non-CSCs were compared. Human prostate CSCs exhibited intense ICAM-1 and VCAM-1 immunoreaction when compared with non-CSCs. These findings were supported by the fact that VCAM-1 on the surface of cancer cells binds to its counter-receptor, the a4 beta 1 integrin (also known as very-late antigen, VLA-4), on metastasis-associated macrophages, triggering VCAM-1-mediated activation of the phosphoinositide 3-kinase growth and survival pathway in cancer cells. Conclusions: The results of this study showed that changes in JAK/STAT pathway are related with adhesion molecules and could affect cancer progression.
  • No Thumbnail Available
    Item
    Cancer stem cell differentiation: TGFβ1 and versican may trigger molecules for the organization of tumor spheroids
    Oktem, G; Sercan, O; Guven, U; Uslu, R; Uysal, A; Goksel, G; Ayla, S; Bilir, A
    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. TGF beta 1 was found to be significantly upregulated in monolayer CSCs. High expression levels of VCAN, COL7A1, 1TG beta 3, 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 TG beta 1 in monolayer cultures and VCAN in spheroids. CSCs were found to possess multipotential differentiation capabilities through upregulation and/or downregulation of their markers. TGF beta 1 is a triggering molecule, it stimulates versican, Co17A1, ITG beta 3 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.