靶向麩醯胺酸代謝以逆轉雙調蛋白介導之軟骨肉瘤順鉑抗藥性：從分子機制到潛在治療策略探討

軟骨肉瘤為骨骼系統常見的惡性腫瘤，臨床治療困難且預後不佳。目前主要治療方式仍以手術切除為主，然而由於軟骨肉瘤對傳統放射治療及化學治療具有顯著抗性，使其術後復發率及轉移率偏高。順鉑(cisplatin)為臨床上常使用之化療藥物之一，雖在多種惡性腫瘤治療中展現良好效果，但在軟骨肉瘤中卻常因細胞抗藥性而導致治療效果不佳。本研究運用人類軟骨肉瘤細胞株SW1353及其順鉑抗藥細胞株SW1353-R，透過次世代RNA定序(RNA sequencing)技術，發現順鉑抗藥細胞株中特別活化麩醯胺酸(glutamine)代謝途徑，而非葡萄糖代謝途徑。進一步研究發現，麩醯胺酸轉運蛋白 (Solute carrier family 1 member 5, SLC1A5)及麩醯胺酸? (Glutaminase, GLS)在抗藥細胞中表現明顯提高，促使大量麩醯胺酸進入細胞並透過轉化產生NADPH，降低活性氧物質(Reactive Oxygen Species, ROS)累積，藉此增強軟骨肉瘤細胞對順鉑的抗藥能力。此外，本研究也探討表皮生長因子受體(Epidermal Growth Factor Receptor, EGFR)的配體雙調蛋白(Amphiregulin, AR)在軟骨肉瘤中對麩醯胺酸代謝的調控作用。實驗證實，AR透過活化MEK/ERK訊息傳導路徑與轉錄因子NrF2，直接促進SLC1A5及GLS基因的表現，從而強化麩醯胺酸代謝並提高腫瘤細胞之抗藥性。更進一步地，在動物模式中，以shRNA方式降低AR表現後，腫瘤內SLC1A5、GLS與NrF2表現量皆明顯降低，同時顯著抑制腫瘤生長與抗藥性。綜合以上研究結果，麩醯胺酸代謝途徑在軟骨肉瘤順鉑抗藥機轉中具有關鍵角色，而AR則為調控此代謝途徑的重要分子。未來透過開發抑制AR、SLC1A5或GLS的標靶藥物或抗體治療，可能成為克服軟骨肉瘤順鉑抗藥性的有效策略，對於改善患者預後將具有重要的臨床價值。

Chondrosarcoma is a malignant tumor commonly affecting the skeletal system, characterized by challenging clinical management and poor prognosis. The primary treatment strategy currently relies on surgical resection; however, the notable resistance of chondrosarcoma to conventional radiotherapy and chemotherapy significantly increases the risks of recurrence and metastasis. Cisplatin is frequently used as a chemotherapeutic agent in various cancers, but its efficacy is severely limited in chondrosarcoma due to intrinsic cellular resistance. This study utilized human chondrosarcoma cell line SW1353 and its cisplatin-resistant variant SW1353-R, employing next-generation RNA sequencing technology to identify metabolic alterations associated with cisplatin resistance. Our findings revealed a marked activation of glutamine metabolism, rather than glucose metabolism, in cisplatin-resistant cells. Further analysis demonstrated that increased expression of the glutamine transporter solute carrier family 1 member 5 (SLC1A5) and glutaminase(GLS) in resistant cells facilitated enhanced glutamine uptake, leading to augmented NADPH production and reduced reactive oxygen species (ROS) accumulation. This metabolic adaptation thereby significantly reinforced cellular resistance to cisplatin. Moreover, we investigated the regulatory role of Amphiregulin (AR), an epidermal growth factor receptor (EGFR) ligand, in glutamine metabolism within chondrosarcoma cells. Our experiments confirmed that AR activates the MEK/ERK signaling pathway and the transcription factor NrF2, directly promoting the expression of SLC1A5 and GLS, consequently strengthening glutamine metabolism and chemoresistance. Furthermore, in vivo studies utilizing shRNA-mediated AR knockdown resulted in significant reductions in SLC1A5, GLS, and NrF2 expression, accompanied by notable inhibition of tumor growth and resistance. In conclusion, this study highlights the critical role of glutamine metabolism in the cisplatin resistance mechanism of chondrosarcoma, with AR serving as a crucial regulator of this metabolic pathway. Targeting AR, SLC1A5, or GLS with specific inhibitors or antibodies could potentially overcome chemoresistance in chondrosarcoma, thereby offering significant clinical benefits in improving patient outcomes.