Sustained Epigenetic Drug Delivery Depletes Cholesterol-Sphingomyelin Rafts from Resistant Breast Cancer Cells, Influencing Biophysical Characteristics of Membrane Lipids.
Sustained Epigenetic Drug Delivery Depletes Cholesterol-Sphingomyelin Rafts from Resistant Breast Cancer Cells, Influencing Biophysical Characteristics of Membrane Lipids.
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DOI：
10.1021/acs.langmuir.5b02601
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发表时间：
2015-10-27
期刊：
影响因子：
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通讯作者：
Labhasetwar V
中科院分区：
文献类型：
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作者：
Raghavan V;Vijayaraghavalu S;Peetla C;Yamada M;Morisada M;Labhasetwar V
细胞膜脂质组成可以极大地影响细胞膜的生物物理性质，从而影响各种细胞功能。我们以前表明，脂质合成在耐药乳腺癌细胞（MCF-7/ADR）的膜中发生了改变;它们形成了比敏感细胞膜（MCF-7）更坚硬，疏水的脂质单层。这些耐药细胞膜脂质的变化，归因于表观遗传畸变，显著影响药物转运和内吞功能，从而影响抗癌药物的疗效。本研究的目的是确定表观遗传药物5-氮杂-2 ′-脱氧胞苷（DAC），缓释纳米凝胶（DAC-NGs）中交付，对耐药细胞的膜脂质的组成和生物物理特性的影响。用DAC溶液（DAC-sol）或DAC-NG处理抗性和敏感细胞，分离细胞膜脂质并分析脂质组成和生物物理性质。在耐药细胞中，我们发现随着培养时间的增加，胆固醇-鞘磷脂（CHOL-SM）筏的形成增加，而DAC处理减少了它们的形成。一般而言，DAC-NG在改变脂质组成方面的作用大于DAC-sol。DAC治疗还引起已知增加膜流动性的某些磷脂和中性脂质水平升高，同时降低已知增加膜刚性的某些脂质水平。等温线数据显示DAC处理后脂质膜流动性增加，归因于CHOL-SM筏（层状β [Lβ]结构或有序凝胶）水平降低和形成层状α结构（Lα，液晶相）的脂质相应增加。敏感的细胞显示出边缘或不显著的变化，在DAC处理后的脂质谱，这表明影响脂质生物合成的表观遗传变化是更具体的耐药细胞。由于膜流动性在药物转运和内吞功能中起主要作用，因此用具有改变的脂质分布的表观遗传药物治疗耐药细胞可以促进抗癌药物转运，以克服联合治疗中的获得性耐药性。
Cell-membrane lipid composition can greatly influence biophysical properties of cell membranes, affecting various cellular functions. We previously showed that lipid synthesis becomes altered in the membranes of resistant breast cancer cells (MCF-7/ADR); they form a more rigid, hydrophobic lipid monolayer than do sensitive cell membranes (MCF-7). These changes in membrane lipids of resistant cells, attributed to epigenetic aberration, significantly affected drug transport and endocytic function, thus impacting the efficacy of anticancer drugs. The present study’s objective was to determine the effects of the epigenetic drug 5-aza-2′-deoxycytidine (DAC), delivered in sustained-release nanogels (DAC-NGs), on the composition and biophysical properties of membrane lipids of resistant cells. Resistant and sensitive cells were treated with DAC in solution (DAC-sol) or DAC-NGs, and cell-membrane lipids were isolated and analyzed for lipid composition and biophysical properties. In resistant cells, we found increased formation of Cholesterol-Sphingomyelin (CHOL-SM) rafts with culturing time, whereas DAC treatment reduced their formation. In general, the effect of DAC-NGs was greater in changing the lipid composition than with DAC-sol. DAC treatment also caused a rise in levels of certain phospholipids and neutral lipids known to increase membrane fluidity while reducing the levels of certain lipids known to increase membrane rigidity. Isotherm data showed increased lipid membrane fluidity following DAC treatment, attributed to decrease levels of CHOL-SM rafts (lamellar beta [Lβ] structures or ordered gel) and a corresponding increase in lipids that form lamellar alpha structures (Lα, liquid crystalline phase). Sensitive cells showed marginal or insignificant changes in lipid profile following DAC-treatment, suggesting that epigenetic changes affecting lipid biosynthesis are more specific to resistant cells. Since membrane fluidity plays a major role in drug transport and endocytic function, treatment of resistant cells with epigenetic drugs with altered lipid profile could facilitate anticancer drug transport to overcome acquired drug resistance in a combination therapy.