Bone biomineralization in osteosarcoma: a multimodal multiscale in/ex vivo study through synchrotron-based X-ray and NMR techniques

Osteosarcoma (OS) is a rare and aggressive bone tumor mainly affecting adolescents and young adults. Recent studies suggested that dysfunctions in osteogenic differentiation may contribute to OS genesis and development, leading to a malignant environment that promotes cancer growth and migration. OS clinical diagnosis involves investigating persistent bone pain, swelling, and fractures through radiological imaging and biopsy. In addition, treatment typically involves a multimodal approach combining surgical resection of the tumor and chemotherapy before and after surgery. This thesis aims to provide new insights into osteosarcoma through a comprehensive multiscale characterization of the tumor, exploiting advanced synchrotron-based X-ray and magnetic resonance techniques. SaOS-2 cells were induced to differentiate into osteoblasts and were studied during the early stages of biomineralization. Mineral matrix formation was monitored exploiting synchrotron-based X-ray techniques, suggesting a mechanism based on the interaction between mitochondria and vesicles. OS is characterized by uncontrolled cells proliferation and consequent generation of an abnormal tissue microenvironment that promotes tumor growth and metastasis. Therefore, an extensive structural and morphological characterization of osteosarcoma tissue holds great potential for identifying new targets and therapeutic strategies. Synchrotron-based X-ray techniques were utilized to analyze resected human osteosarcoma tissues, revealing differences in morphology, mineral, and chemical composition compared to normal bone. Currently, invasive biopsy remains the gold standard for identifying bone sarcomas and monitoring their pathological progression. Nuclear magnetic resonance (NMR) techniques at ultra-high field, particularly diffusion-weighted imaging and magnetic resonance spectroscopy, showed promise in characterizing bone sarcomas cellularity and metabolism. In conclusion, thanks to the combination of synchrotron-based and NMR techniques, this work tackles the challenge to bridge the gap between cellular and clinical aspects of osteosarcoma. Moreover, the multimodal approach provides new insights into bone sarcomas, paving the way for the development of improved therapeutic strategies and more precise diagnostic tools.