Stem and osteosarcoma cells treated with calcium phosphate cements as a model of study to assay in vitro bone regeneration and anticancer activity

Osteosarcoma (OS) is an aggressive malignant bone cancer, which mainly affects pediatric and young adult patients. Osteosarcoma treatments include systemic chemotherapy and surgical resection. OS treatments may present complications due to toxicity of chemotherapeutic agents and novel treatment approaches have been proposed to improve the treatment efficacy. The development of bioactive bone substitutes combining effective regenerative and antitumor features over time is highly demanded. Herein, an injectable and nanostructured st rontium doped calcium phosphate scaffold (SrCPC) was investigated as drug delivery system to combine bone tissue regeneration and anticancer treatment by controlled release of methotrexate (MTX) and doxorubicin (DOX), coded as SrCPC MTX and SrCPC DOX, resp ectively. The drug loaded cements were tested in an in vitro model of human OS cell line (SAOS 2) and fluorescent engineered OS cell line (eGFP SAOS 2). The ability of doped scaffolds to induce SAOS 2 cell death and apoptosis was assessed analyzing cell pr oliferation and Caspase 3/7 activities. The regenerative potential of SrCPC material was investigated in human adipose derived mesenchymal stem cells (hASCs) performing, at several time points (i) Alizarin Red Staining, (ii) E.L.I.S.A to test osteocalcin p rotein expression, (iii) Real Time PCR Array to test the osteogenic gene expression. The delivery system induced cell killing effect and apoptosis in SAOS 2. In addition, no doped material, SrCPC, demonstrates a good cytocompatibility and it induced up reg ulation of osteogenic genes involved in the skeletal development pathway, together with osteogenic markers. The proposed approach, based on the local, sustained release of anticancer drugs from nanostructured biomimetic drug loaded cements seems to be a pr omising approach aiming to combine bone regeneration and anticancer therapy.