Abstract
Although bone metastases represent a major challenge in the natural history of breast cancer (BC), the complex interactions involved have hindered the development of robust in vitro models. The aim of this work is the development of a preclinical model of cancer and bone stromal cells to mimic the bone microenvironment. We studied the effects on osteoclastogenesis of BC cells and Mesenchymal stem cells (MSC) cultured alone or in combination. We also analyzed: (a) whether the blockade of the Epithelial Growth Factor Receptor (EGFR) pathway modified their influence on monocytes towards differentiation, and (b) the efficacy of bone-targeted therapy on osteoclasts. We evaluated the osteoclastogenesis modulation of human peripheral blood monocytes (PBMC) indirectly induced by the conditioned medium (CM) of the human BC cell line SCP2, cultured singly or with MSC. Osteoclastogenesis was evaluated by TRAP analysis. The effect of the EGFR blockade was assessed by treating the cells with gefitinib, and analyzed with the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and Western Blot (WB). We observed that SCP2 co-cultured with MSC increased the differentiation of PBMC. This effect was underpinned upon pre-treatment of the co-culture with gefitinib. Co-culture of SCP2 with MSC increased the expression of both the bone-related marker Receptor Activator of Nuclear Factor κB (RANK) and EGFR in BC cells. These upregulations were not affected by the EGFR blockade. The effects of the CM obtained by the cells treated with gefitinib in combination with the treatment of the preosteoclasts with the bone-targeted agents and everolimus enhanced the inhibition of the osteoclastogenesis. Finally, we developed a fully human co-culture system of BC cells and bone progenitor cells. We observed that the interaction of MSC with cancer cells induced in the latter molecular changes and a higher power of inducing osteoclastogenesis. We found that blocking EGFR signaling could be an efficacious strategy for breaking the interactions between cancer and bone cells in order to inhibit bone metastasis.
Highlights
Bone metastases are a common event in breast cancer (BC) patients [1], often leading to severe symptoms such as pain, bone fractures, spinal cord compression and hypercalcemia [2]
We investigated the effect of Gef on the osteoclastogenic potential of conditioned medium (CM) from SCP2 and Mesenchymal stem cells (MSC) mono- and co-cultures
Pre-osteoclasts were cultured either in differentiation medium (DM), or in pre-osteoclast medium or in pre-osteoclast medium supplemented with 20% of CM collected in the COCO assay
Summary
Bone metastases are a common event in breast cancer (BC) patients [1], often leading to severe symptoms such as pain, bone fractures, spinal cord compression and hypercalcemia [2]. The inhibition of either the maturation or the activity of osteoclasts has already proven effective in treating bone metastases [1,9], and has led to the development of many osteoclast-targeted drugs [10,11]. These pharmacological agents, which constitute the bone-targeted therapy, are mainly represented by the anti-RANKL antibody denosumab (Den), and bisphosphonates, such as zoledronic acid (Zol). The available data from both preclinical studies and clinical observations may pave the way for the use of Gef and other TKIs for the treatment of bone metastases
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
