Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, District of Columbia, USA.
Ocean Genomics Inc., Pittsburgh, Pennsylvania, USA.
Mol Carcinog. 2024 Feb;63(2):209-223. doi: 10.1002/mc.23646. Epub 2023 Oct 11.
Cyclin dependent kinase 4 and 6 inhibitors such as abemaciclib are routinely used to treat metastatic estrogen receptor positive (ER+) breast cancer. However, adaptive mechanisms inhibit their effectiveness and allow for disease progression. Using ER+ breast cancer cell models, we show that acquired resistance to abemaciclib is accompanied by increase in metastatic potential. Mass spectrometry-based proteomics from abemaciclib sensitive and resistant cells showed that lysosomal proteins including CTSD (cathepsin D), cathepsin A and CD68 were significantly increased in resistant cells. Combination of abemaciclib and a lysosomal destabilizer, such as hydroxychloroquine (HCQ) or bafilomycin A1, resensitized resistant cells to abemaciclib. Also, combination of abemaciclib and HCQ decreased migration and invasive potential and increased lysosomal membrane permeability in resistant cells. Prosurvival B cell lymphoma 2 (BCL2) protein levels were elevated in resistant cells, and a triple treatment with abemaciclib, HCQ, and BCL2 inhibitor, venetoclax, significantly inhibited cell growth compared to treatment with abemaciclib and HCQ. Furthermore, resistant cells showed increased levels of Transcription Factor EB (TFEB), a master regulator of lysosomal-autophagy genes, and siRNA mediated knockdown of TFEB decreased invasion in resistant cells. TFEB was found to be mutated in a subset of invasive human breast cancer samples, and overall survival analysis in ER+, lymph node-positive breast cancer showed that increased TFEB expression correlated with decreased survival. Collectively, we show that acquired resistance to abemaciclib leads to increased metastatic potential and increased levels of protumorigenic lysosomal proteins. Therefore, the lysosomal pathway could be a therapeutic target in advanced ER+ breast cancer.
细胞周期蛋白依赖性激酶 4 和 6 抑制剂（如阿贝西利）通常用于治疗转移性雌激素受体阳性（ER+）乳腺癌。然而，适应性机制会抑制其疗效并导致疾病进展。我们使用 ER+乳腺癌细胞模型表明，对阿贝西利的获得性耐药伴随着转移潜能的增加。来自阿贝西利敏感和耐药细胞的基于质谱的蛋白质组学研究表明，溶酶体蛋白，包括 CTSD（组织蛋白酶 D）、组织蛋白酶 A 和 CD68，在耐药细胞中显著增加。阿贝西利与溶酶体稳定剂（如羟氯喹[HCQ]或巴弗洛霉素 A1）联合使用可使耐药细胞重新对阿贝西利敏感。此外，阿贝西利和 HCQ 的联合使用降低了耐药细胞的迁移和侵袭潜力，并增加了溶酶体膜通透性。耐药细胞中存活的 B 细胞淋巴瘤 2（BCL2）蛋白水平升高，与阿贝西利和 HCQ 联合治疗相比，阿贝西利、HCQ 和 BCL2 抑制剂 venetoclax 的三联治疗显著抑制了细胞生长。此外，耐药细胞显示出转录因子 EB（TFEB）水平升高，TFEB 是溶酶体自噬基因的主要调节因子，siRNA 介导的 TFEB 敲低可降低耐药细胞的侵袭性。在侵袭性人类乳腺癌样本中发现 TFEB 发生了突变，在 ER+、淋巴结阳性乳腺癌的总生存分析中，TFEB 表达增加与生存时间缩短相关。总之，我们表明，阿贝西利的获得性耐药导致转移潜能增加和促肿瘤性溶酶体蛋白水平升高。因此，溶酶体途径可能是晚期 ER+乳腺癌的治疗靶点。
