Search

In glioblastoma multiforme (GBM), cancer stem cells (CSCs) are thought to be responsible for gliomagenesis, resistance to treatment and recurrence. Despite increasing knowledge of the GBM biomolecular characterization and breakthrough in treatment, the prognosis in the great majority of patients is poor as almost all tumors recur in peritumor tissue. This site of alterations seems to harbor CSCs that show some differences when compared to CSCs derived from GBM. By means of immunocytochemistry, Western blotting and RT-PCR, we have compared CSCs derived from GBM (GCSCs) to those isolated from peritumor tissue (PCSCs) as to the expression of molecules linked to stemness (Nestin, Musashi-1, SOX2), proliferation and apoptosis (pERK1/2 and pJNKs), migration/invasion, angiogenesis, and hypoxia (reelin, GD3, NG2, VEGF, VEGFR1/2, HIF1α, and HIF2α). Furthermore, comparison of growth rate, frequency of tumor initiating cells (TICs), tumorigenicity in Scid/bg mice, and ultrastructure between the two CSC populations was performed. Finally, we analyzed the effect of different chemotherapeutic agents (temozolomide, etoposide, irinotecan and carboplatin) on proliferation of both GCSCs and PCSCs. All the molecules analyzed were expressed in the two populations of CSCs. Among the investigated markers, nestin, pJNKs, Musashi-1, NG2 and VEGFR1 were found to be significantly increased in GCSCs if compared with PCSCs. Moreover, GCSCs grew at a higher rate and showed a greater frequency of TICs. Animal survival time revealed that mice receiving GCSCs died significantly earlier than mice inoculated with PCSCs. Only PCSCs ultrastructure showed fully organized desmosomes and gap junctions. All the chemotherapeutic agents used inhibited proliferation of both GCSCs and PCSCs, although with different efficiency. Moreover, each drug had similar effect on the GCSCs and PCSCs derived from the same patient. These findings support the need for a complete characterization of GCSCs and PCSCs to optimi

Background: Despite the recognized contribution of the stroma to breast cancer development and progression, the effective therapeutic targeting of the tumor microenvironment remains a challenge to be addressed. We previously reported that normal fibroblasts (NFs) and, notably, breast cancer-associated fibroblasts (CAFs) induced epithelial-mesenchymal transition and increase in cell membrane fluidity and migration in both well- (MCF-7) and poorly-differentiated (MDA-MB-231) breast cancer cells. This study was designed to better define the role played, especially by CAFs, in promoting breast tumor cell migration. Materials and Methods: Fibroblast/breast cancer cell co-cultures were set up to investigate the influence of NFs and CAFs on gene and protein expression of Stearoyl-CoA desaturase 1 (SCD1), the main enzyme regulating membrane fluidity, as well as on the protein level and activity of its transcription factor, the sterol regulatory element-binding protein 1 (SREBP1), in MCF-7 and MDA-MB-231 cells. Migration was evaluated by wound healing assay in SCD1-inhibited (by small interfering RNA, siRNA, or pharmacologically) tumor cells. To assess the role of stromal-derived signals in cancer cell migration speed, cell tracking analysis was performed in the presence of neutralizing antibodies to hepatocyte growth factor, transforming growth factor-β or basic fibroblast growth factor. Results: A 2-3 fold increase in SCD1 mRNA and protein expression as well as an induction of SREBP1 DNA binding activity has been induced, particularly by CAFs, in the two cancer cell lines. Both siRNA-mediated and pharmacological inhibition of SCD1 impaired tumor cells migration. Fibroblast-triggered increase in cancer cell migration speed was markedly reduced or abolished by neutralizing the above growth factors. Conclusions: These results provide further insights in understanding the role of CAFs in promoting tumor cell migration, which may help to design new stroma-based therapeutic stra

It is widely accepted that glioblastoma (GBM) develops from cancer stem cells (CSCs), a subset of stem-like cells displaying high resistance to treatment. Our recent findings showed the existence of a CSC type, residing in GBM peritumor tissue (PCSCs), that bears distinct characteristics from CSCs of the tumor mass (GCSCs) and that, after surgical resection, might represent a reservoir of cells able to recapitulate the tumor. In this setting, characterization of PCSCs appears to be crucial in order to identify novel effective therapeutic targets. Thus, our aim was to investigate GCSCs and PCSCs role in angiogenesis, a key event in both GBM and peritumor tissue, whose vasculature shows features similar to those found in the tumor mass. In particular, we analyzed, by immunocytochemistry (ICC), Western blotting or real-time PCR, the expression of molecules involved in hypoxia and angiogenesis, such as HIF1α, HIF2α, and VEGF along with its receptors (VEGFR1, VEGFR2). ICC has highlighted the presence and the specific localization of these molecules in both GCSCs and PCSCs. The two cell populations showed comparable levels of VEGF. The transcript of VEGFR1 was in general expressed at higher levels in GCSCs than in PCSCs, while VEGFR2 mRNA and protein did not show a unique trend of expression. The presence of VEGF and its receptors in both GCSCs and PCSCs suggests that, besides well-known paracrine loops, autocrine signalings are also involved in tumor angiogenesis. Moreover, the expression of angiogenesis markers in PCSCs suggests these cells to have a direct role in peritumor tissue new vessel formation. In this regard, PCSCs should be considered a promising therapeutic target to counteract the angiogenesis-supported tumor progression. Supported by FIRB Accordi di Programma 2010