Avnet Sofia, Lemma Silvia, Cortini Margherita, Di Pompo Gemma, Perut Francesca, Lipreri Maria Veronica, Roncuzzi Laura, Columbaro Marta, Errani Costantino, Longhi Alessandra, Zini Nicoletta, Heymann Dominique, Dominici Massimo, Grisendi Giulia, Golinelli Giulia, Consolino Lorena, Longo Dario Livio, Nanni Cristina, Righi Alberto, Baldini Nicola
Department of Biomedical and Neuromotor Sciences, University of Bologna, 40127 Bologna, Italy.
BST Biomedical Science and Technologies Lab, IRCCS Istituto Ortopedico Rizzoli, 40136 Bologna, Italy.
Cancers (Basel). 2021 Nov 22;13(22):5855. doi: 10.3390/cancers13225855.
Osteosarcoma is the most frequent primary malignant bone tumour with an impressive tendency to metastasise. Highly proliferative tumour cells release a remarkable amount of protons into the extracellular space that activates the NF-kB inflammatory pathway in adjacent stromal cells. In this study, we further validated the correlation between tumour glycolysis/acidosis and its role in metastases. In patients, at diagnosis, we found high circulating levels of inflammatory mediators (IL6, IL8 and miR-136-5p-containing extracellular vesicles). IL6 serum levels significantly correlated with disease-free survival and F-FDG PET/CT uptake, an indirect measurement of tumour glycolysis and, hence, of acidosis. In vivo subcutaneous and orthotopic models, co-injected with mesenchymal stromal (MSC) and osteosarcoma cells, formed an acidic tumour microenvironment (mean pH 6.86, as assessed by in vivo MRI-CEST pH imaging). In these xenografts, we enlightened the expression of both IL6 and the NF-kB complex subunit in stromal cells infiltrating the tumour acidic area. The co-injection with MSC also significantly increased lung metastases. Finally, by using 3D microfluidic models, we directly showed the promotion of osteosarcoma invasiveness by acidosis via IL6 and MSC. In conclusion, osteosarcoma-associated MSC react to intratumoural acidosis by triggering an inflammatory response that, in turn, promotes tumour invasiveness at the primary site toward metastasis development.
骨肉瘤是最常见的原发性恶性骨肿瘤，具有显著的转移倾向。高增殖性肿瘤细胞向细胞外空间释放大量质子，激活相邻基质细胞中的NF-κB炎症途径。在本研究中，我们进一步验证了肿瘤糖酵解/酸中毒与其在转移中的作用之间的相关性。在患者诊断时，我们发现炎症介质（IL6、IL8和含miR-136-5p的细胞外囊泡）的循环水平较高。IL6血清水平与无病生存期和F-FDG PET/CT摄取显著相关，F-FDG PET/CT摄取是肿瘤糖酵解以及酸中毒的间接测量指标。在体内皮下和原位模型中，共注射间充质基质细胞（MSC）和骨肉瘤细胞，形成了酸性肿瘤微环境（通过体内MRI-CEST pH成像评估，平均pH值为6.86）。在这些异种移植中，我们发现浸润肿瘤酸性区域的基质细胞中IL6和NF-κB复合物亚基均有表达。与MSC共注射也显著增加了肺转移。最后，通过使用3D微流控模型，我们直接证明了酸中毒通过IL6和MSC促进骨肉瘤的侵袭性。总之，骨肉瘤相关的MSC通过触发炎症反应对肿瘤内酸中毒作出反应，进而促进原发性肿瘤部位向转移发展的侵袭性。
