Inson Ingon, Chutoe Chartinun, Kanjanapipak Janjira, Lertsuwan Kornkamon
Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok, Thailand.
Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, Thailand.
Cancer Med. 2025 Feb;14(4):e70709. doi: 10.1002/cam4.70709.
Breast cancer frequently metastasizes to bones. The interaction between breast cancer cells and bone cells results in osteolytic lesions by disrupting the balance between osteoblast-mediated bone production and osteoclast-mediated bone resorption. This study aims to investigate the effects of the cannabinoid receptor type 2 (CB2) agonist, GW405833, on interactions between breast cancer cells and osteoblasts as well as its impact on breast cancer-induced osteoclastogenesis.
MATERIALS & METHODS: MDA-MB-231, UMR-106, RAW 264.7 cells were used to represent breast cancer cells, osteoblast-like cells and macrophage-osteoclast precursor cells, respectively. Cell viability was evaluated by MTT assay, and breast cancer cell invasion was assessed by Transwell invasion assay. Tartrate-resistant acid phosphatase (TRAP) staining was utilized to evaluate osteoclastogenesis.
Our results demonstrated that GW405833 disrupted MDA-MB-231-induced UMR-106 cell death and promoted UMR-106 cell viability. The underlying mechanism of these effects was determined in this study. GW405833 reduced AKT phosphorylation in MDA-MB-231 cells without affecting mTOR protein expression or its phosphorylation. Conversely, in UMR-106 cells, GW405833 induced AKT and mTOR phosphorylated protein. Furthermore, the mTOR inhibitor reversed the GW405833-induced recovery of UMR-106 cell viability under MDA-MB-231-derived conditioned media (CM) exposure. These findings underscore the critical role of the AKT/mTOR pathway in mediating GW405833's inhibitory effects on cancer-bone interactions. Additionally, GW405833 suppressed osteoblast-enhanced breast cancer cell invasion and the expression of invasion-related proteins in both cell types, along with reducing osteoclastogenic factors induced by MDA-MB-231 CM in UMR-106 cells and suppressing MDA-MB-231 CM-enhanced osteoclastogenesis in RAW 264.7 cells.
This study highlights the therapeutic potential of cannabinoid receptor agonist for treating breast cancer bone metastasis and bone-related complications.
乳腺癌常转移至骨骼。乳腺癌细胞与骨细胞之间的相互作用通过破坏成骨细胞介导的骨生成与破骨细胞介导的骨吸收之间的平衡，导致溶骨性病变。本研究旨在探讨2型大麻素受体（CB2）激动剂GW405833对乳腺癌细胞与成骨细胞之间相互作用的影响及其对乳腺癌诱导的破骨细胞生成的影响。
分别使用MDA-MB-231、UMR-106、RAW 264.7细胞代表乳腺癌细胞、成骨样细胞和巨噬细胞-破骨细胞前体细胞。通过MTT法评估细胞活力，通过Transwell侵袭试验评估乳腺癌细胞侵袭能力。采用抗酒石酸酸性磷酸酶（TRAP）染色评估破骨细胞生成。
我们的结果表明，GW405833可阻止MDA-MB-231诱导的UMR-106细胞死亡并促进UMR-106细胞活力。本研究确定了这些作用的潜在机制。GW405833可降低MDA-MB-231细胞中AKT的磷酸化水平，而不影响mTOR蛋白表达或其磷酸化水平。相反，在UMR-106细胞中，GW405833可诱导AKT和mTOR磷酸化蛋白。此外，mTOR抑制剂可逆转在MDA-MB-231来源的条件培养基（CM）作用下GW405833诱导的UMR-106细胞活力恢复。这些发现强调了AKT/mTOR信号通路在介导GW405833对癌骨相互作用的抑制作用中的关键作用。此外，GW405833可抑制成骨细胞增强的乳腺癌细胞侵袭以及两种细胞类型中侵袭相关蛋白的表达，同时降低UMR-106细胞中MDA-MB-231 CM诱导的破骨细胞生成因子水平，并抑制RAW 264.7细胞中MDA-MB-231 CM增强的破骨细胞生成。
本研究突出了大麻素受体激动剂在治疗乳腺癌骨转移及骨相关并发症方面的治疗潜力。
