| 摘要: | 乳癌骨轉移是臨床上具有高度挑戰性的病灶，而骨微環境中的礦物組成與生長因子對腫瘤細胞行為具有重要影響。本研究旨在探討羥基磷灰石(Hydroxyapatite, HAP) 對乳癌細胞礦化行為的調控作用，並分析骨微環境中骨形態發生蛋白 2 (Bone morphogenetic protein 2, BMP2) 的角色。透過建立三維多孔性仿骨支架，分別在不同 HAP 含量 (30%、50%、70%) 及有無 BMP2 的條件下培養乳癌細胞，並結合免疫組織化學染色、西方墨點法、即時聚合酶連鎖反應及茜素紅染色進行分析，同時，為了具備統計學意義，每組以生物性重複三次進行。
結果顯示，BMP2 為乳癌細胞礦化的重要驅動因子，能提升 Runt相關轉錄因子2、鹼性磷酸酶、骨橋蛋白、骨鈣素的表現，促進礦化沉積。而 HAP 的作用則依賴 BMP2 存在與其含量，低含量 HAP (30%) 有利於 BMP2 促礦化，而高含量 HAP (70%) 則削弱 BMP2 的誘導效果。BMP2 未添加時，HAP 對礦化的影響相對有限，但適度 HAP (50%) 仍可能提供部分支持。
綜合結果顯示，HAP 並非單向促進或抑制乳癌細胞礦化，而是透過調控 BMP2 可用性及細胞對訊號的感受性呈現交互性調控。本研究首次系統性評估 HAP 與 BMP2 在乳癌骨轉移礦化中的影響，為理解腫瘤微環境與骨基質互動提供新的見解，亦可作為未來治療策略設計的參考。;Breast cancer bone metastasis represents a major clinical challenge, in which the mineral composition and growth factors within the bone microenvironment play critical roles in regulating tumor cell behavior. This study aimed to investigate the regulatory effects of hydroxyapatite (HAP) on breast cancer cell mineralization and to elucidate the role of bone morphogenetic protein-2 (BMP-2) within the bone microenvironment. A three-dimensional porous bone-mimetic scaffold was established, in which breast cancer cells were cultured under varying HAP contents (30%, 50%, and 70%) in the presence or absence of BMP-2. Cellular mineralization and osteogenic-related responses were evaluated using immunohistochemistry, Western blot analysis, quantitative real-time PCR, and Alizarin Red S staining. To ensure
statistical validity, each experimental condition was performed with three independent biological replicates.
The results demonstrated that BMP-2 is a critical driver of breast cancer cell mineralization, significantly enhancing the expression of Runt-related transcription factor 2 (RUNX2), alkaline phosphatase (ALP), osteopontin (OPN), and osteocalcin (OCN), thereby promoting mineral deposition. In contrast, the effects of HAP were dependent on both its content and the presence of BMP-2. Low HAP content (30%) synergistically enhanced BMP-2-induced mineralization, whereas high HAP content (70%) attenuated the osteogenic effects of BMP-2. In the absence of BMP-2, HAP alone exerted limited influence on mineralization; however, a moderate HAP
content (50%) still provided partial supportive effects.
Collectively, these findings indicate that HAP does not act as a unidirectional promoter or inhibitor of breast cancer cell mineralization but instead modulates mineralization through interactive regulation of BMP-2 bioavailability and cellular responsiveness to osteogenic signaling. This study represents the first systematic evaluation of the combined effects of HAP and BMP-2 on mineralization in breast cancer bone metastasis, providing new insights into tumor–bone matrix interactions and offering a potential framework for the development of future therapeutic strategies targeting bone metastatic disease. |
