The hypoxia effect on cancer stem cells

Hypoxia is known as a condition, which is characterized by the lack of oxygen. The hypoxia effect on tumors has a critical important role on maintenance of cancer stem cell phenotype . The aim of this study is to investigate the hypoxia effect on cancer stem cells on 3 dimensional (3D) in vitro culture models. In this study, osteosarcoma stem cells, which are characterized by CD133 surface protein, were isolated from osteosarcoma cell line (SaOs-2) by magnetic-activated cell sorting (MACS) technique. As a control group; osteosarcoma stem cell line (OSCs, Celprogen Inc.) was used. OSCs, CD133+ and CD133- cells were cultivated under hypoxic (1% O2) and normoxic conditions (21% O2) for 3 days. For the 3D model, bacterial cellulose scaffold was used as the culture substrate. 3D morphologies of cells were examined by scanning electron microscopy (SEM); RT-PCR, ALP activity and immunocytochemistry staining were used to demonstrate conservation of the cancer stem cell phenotype in 3D environment under hypoxic conditions. Also cell viability was shown by MTT assay on 3. and 7. culture days. This study is seen as an introduction to develop a 3D hypoxic cancer stem cell based tumor model to study CSC behaviour and tumorigenesis in vitro under. This thesis project was supported by Aliye Üster Foundation.