Kamra Mohini, Chen Yuan-I, Delgado Paula C, Seeley Erin H, Seidlits Stephanie K, Yeh Hsin-Chih, Brock Amy, Parekh Sapun H
Department of Biomedical Engineering, University of Texas at Austin, Austin, TX, 78712, USA.
Department of Metallurgical, Materials, and Biomedical Engineering, University of Texas at El Paso, El Paso, TX, 79968, USA.
Cancer Metab. 2025 Apr 9;13(1):18. doi: 10.1186/s40170-025-00385-3.
While the triggers for the metastatic transformation of breast cancer (BC) cells remain unknown, recent evidence suggests that intrinsic cellular metabolism could be a crucial driver of migratory disposition and chemoresistance. Aiming to decipher the molecular mechanisms involved in BC cell metabolic maneuvering, we study how a ketomimetic (ketone body-rich, low glucose) nutrient medium can engineer the glycocalyx and metabolic signature of BC cells, to further maneuver their response to therapy.
Doxorubicin (DOX) has been used as a model chemotherapeutic in this study. Bioorthogonal imaging was used to assess the degree of sialylation of the glycocalyx along with measurements of drug-induced cytotoxicity and drug internalization. Single cell label-free metabolic imaging has been performed, coupled with measurement of cellular proliferative and migratory abilities, and MS-based metabolomic screens. Transcriptomic analysis of crucial enzymes was performed using total RNA extraction and rt-qPCR.
We found an inverse correlation of glycocalyx sialylation with drug-induced cytotoxicity and drug internalization, where ketomimetic media enhanced sialylation and protected BC cells from DOX. These hypersialylated cells proliferated slower and migrated faster as compared to their counterparts receiving a high glucose media, while exhibiting a preference for glycolysis. These cells also showed pronounced lipid droplet accumulation coupled with an inversion in their metabolomic profile. Enzymatic removal of sialic acid moieties at the glycocalyx revealed for the first time, a direct role of sialic acids as defense guards, blocking DOX entry at the cellular membrane to curtail internalization. Interestingly, the non-cancerous mammary epithelial cells exhibited opposite trends and this differential pattern in cancer vs. normal cells was traced to its biochemical roots, i.e. the expression levels of key enzymes involved in sialylation and fatty acid synthesis.
Our findings revealed that a ketomimetic medium enhances chemoresistance and invasive disposition of BC cells via two main oncogenic pathways: hypersialylation and lipid synthesis. We propose that the crosstalk between these pathways, juxtaposed at the synthesis of the glycan precursor UDP-GlcNAc, furthers advancement of a metastatic phenotype in BC cells under ketomimetic conditions. Non-cancerous cells lack this dual defense machinery and end up being sensitized to DOX under ketomimetic conditions.
虽然乳腺癌（BC）细胞发生转移转化的触发因素尚不清楚，但最近的证据表明，细胞内在代谢可能是迁移倾向和化疗耐药性的关键驱动因素。为了解析BC细胞代谢调控所涉及的分子机制，我们研究了一种酮体模拟物（富含酮体、低糖）营养培养基如何重塑BC细胞的糖萼和代谢特征，以进一步调控其对治疗的反应。
在本研究中，阿霉素（DOX）被用作模型化疗药物。采用生物正交成像技术评估糖萼的唾液酸化程度，并测量药物诱导的细胞毒性和药物内化情况。进行了单细胞无标记代谢成像，并测量了细胞的增殖和迁移能力，以及基于质谱的代谢组学筛选。使用总RNA提取和rt-qPCR对关键酶进行转录组分析。
我们发现糖萼唾液酸化与药物诱导的细胞毒性和药物内化呈负相关，其中酮体模拟物培养基增强了唾液酸化，并保护BC细胞免受DOX的影响。与接受高糖培养基的细胞相比，这些高度唾液酸化的细胞增殖较慢但迁移较快，同时表现出对糖酵解的偏好。这些细胞还显示出明显的脂滴积累，其代谢组学特征也发生了反转。对糖萼上唾液酸部分的酶促去除首次揭示了唾液酸作为防御卫士的直接作用，即阻止DOX在细胞膜上进入以减少内化。有趣的是，非癌性乳腺上皮细胞表现出相反的趋势，这种癌症与正常细胞之间的差异模式可追溯到其生化根源，即参与唾液酸化和脂肪酸合成的关键酶的表达水平。
我们的研究结果表明，酮体模拟物培养基通过两条主要的致癌途径增强BC细胞的化疗耐药性和侵袭性：高度唾液酸化和脂质合成。我们提出，这些途径之间的相互作用，并列于聚糖前体UDP-GlcNAc的合成过程中，在酮体模拟条件下进一步推动了BC细胞转移表型的发展。非癌性细胞缺乏这种双重防御机制，最终在酮体模拟条件下对DOX敏感。
