Spontaneous Osteoclastogenesis in peripheral blood of breast cancer patients

FERNANDEZ VALLONE VB,; DIMASE F.; BATAGELJ E, ; BORDENAVE RH,; MARTINEZ L M ,; LABOVSKY V, ; CHASSEING NA.

Atenas.

Congreso; 3rd Joint Meeting of the European Calcified Tissue Society and the International Bone and Mineral Society (ECTS/IBMS).; 2011

European Calcified Tissue Society and the International Bone and Mineral Society

Background: Osteolytic bone metastases that are found in most of advanced breast cancer patients are a result of the imbalance between osteogenesis and osteoclastogenesis processes. Previous results showed that mesenchymal stem cells (MSC) from bone marrow (BM) of untreated advanced breast cancer patients (BCP: infiltrative ductal breast carcinoma, clinical stage III and IV, without bone and BM metastasis and without any other bone disease) had lower capacity to form CFU-F (lower cloning efficiency) and a decrease in the osteogenic potential, compared to healthy volunteers (HV). MSC and osteoblasts regulate osteoclastic differentiation. We have already observed spontaneous osteoclastogenesis (SpOC) in BM of advanced BCP that show us the imbalance between the processes. We, now, want to study if this observation correlates with peripheral blood. Mathodology: Peripheral Blood monocytes (PBmo) from 5 BCP and 5 HV were cultured in the presence of M-CSF and 10% FBS. At day 3 the cultures were stimulated with RANKL or not (spontaneous) and M-CSF. After 16 days cells with 3-5 nucleus and TRAP+ were counted as osteoclasts (OC). For OC characterization with specific antibodies: anti-MMP9, Src and vitronectin, PBmo were cultured over bovine cortical bone slices for 16 days and immunocytochemistry revealed with DAB-Peroxidase was performed. Functionality was assayed with Acridine Orange to visualize acidify of resorption lacunae. Results: SpOC was observed in BCP vs HV (%OC= 25.7+/-0.5 vs 5.9+/-3.5, p=0.002) and both groups responded to rhRANKL. OC obtained were functional and positive for specific markers. PB-SpOC could be related to higher levels of sRANKL and Dkk-1 observed in BCP-PB-plasma compared to HV (203+/-37 vs low 78pg/ml and 11,361+/-1,299 vs 7,268+/-1,221; p=0.03). PB-SpOC may also be related to higher number of circulating preosteoclasts (CD11b+, RANK+, CD51/61+, c-fms+) observed in PB by flow cytometry. Moreover higher levels of TBARS and lower levels of antioxidants like alpha-tocopherol and total ubiquinol-10, previously found in PB plasma from these advanced BCP, suggest a significant increase in both lipid oxidation and ROS production which was recently associated with an increase in osteoclastogenesis and bone resorption and a decrease in osteogenesis process. Conclusion: We consider important the study of the osteoclastogenic potential of PB-Mo, a non-invasive method, as possible prognostic factor of future bone disorders that may favor the invasion of BCcells into bone.