Mesenchymal stromal cells expressing granulocyte macrophage colony-stimulating factor by in in vitro trasnscription mRNA inhibited tumor growth in mice.

CANTERO MJ; BAYO J; FIORE E; DOMINGUEZ L; BUELONI B; ATORRASAGASTI C; MAZZOLINI G; MALVICINI M; GARCIA M

Congreso; Reunión Conjunta SAIC SAI&FAIC SAFIS 2022; 2022

Introduction: Mesenchymal stromal cells (MSCs) have been used as carriers of anti-tumoral agents due to their capacity to home to tumors. It has also been demonstrated that the granulocyte macrophage colony-stimulating factor (GM-CSF) reduced tumoral growth by improving the antitumor immune response. On the other hand, it has been reported that low doses of doxorubicin (dox) may induce immunogenic cell death improving the recruitment of immune cells. The aim of this work was to determine the therapeutic effect of MSCs expressing GM-CSF in combination with low doses of doxorubicin (dox) in a murine model of hepatocellular carcinoma (HCC). Methods: GM-CSF expressing MSCs were obtained by transfection of in vitro transcribed mRNA (IVT mRNA). GM-CSF production was determined by ELISA. MSC expressing GM-CSF (MSC/GM-CSF) were characterized by migration assay and surface markers evaluation by flow cytometry. Murine model of HCC was developed by subcutaneous inoculation of HCC cells Hepa129 (1 x 106 cells) in C3Hmice. Then, once tumors reach ~40 mm3 mice were treated with PBS (control group), dox 5 mg/Kg (dox group) or dox 5 mg/Kg + MSC/GM-CSF (dox/GM-MSC group) at a dose of 1 x 105 cells expressing 0.045 μg/ml of GM-CSF by intratumoral (i.t.) injection. Tumor growth was measured three times a week. Results: ELISA of conditioned media of MSC/GM-CSF indicates that engineered MSCs are able to produce high levels of GM-CSF. In addition, migratory capacity and surface markers of MSCs were not modified by GM-CSF expression. Interesting, treatment with dox/GM-MSC not only reduced tumor growth but also expanded survival of mice in comparison with other groups (p