PDF(Pubmed)
Abstract：
OBJECTIVE: Estrogen receptor-positive (ER+) breast cancer represents about 80% of cases, tamoxifen is the election neoadjuvant chemotherapy. However, a large percentage of patients develop chemoresistance, compromising recovery. Clinical evidence suggests that high plasmatic levels of low-density lipoproteins (LDL) could promote cancer progression. The present study analyzed the effect of LDL on the primary plasmatic active Tamoxifen\'s metabolites resistance acquisition, 4-hydroxytamoxifen (4OH-Tam) and 4-hydroxy-N-desmethyl-tamoxifen (endoxifen), in breast cancer ERα + cells (MCF-7).
METHODS: Two resistant cellular variants, MCF-7Var-H and MCF-7Var-I, were generated by a novel strategy and their phenotype features were evaluated. Phenotypic assessment was performed by MTT assays, cytometry, immunofluorescence microscopy, zymography and protein expression analysis.
RESULTS: MCF-7Var-H, generated only with tamoxifen metabolites, showed a critical down-regulation in hormone receptors, augmented migration capacity, metalloprotease 9 extracellular medium excretion, and a mesenchymal morphology in contrast with native MCF-7, suggesting the transition towards Triple-negative breast cancer (TNBC) phenotype. In contrast, MCF-7Var-I which was generated in a high LDL media, showed only a slight upregulation in ER and other less noticeable metabolic adaptations. Results suggest a potential role of transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) in phenotypic differences observed among variants.
CONCLUSIONS: LDL high or low concentrations during Tamoxifen´s metabolites chemoresistance acquisition leads to different cellular mechanisms related to chemoresistance. A novel adaptative cellular response associated with Nrf2 activity could be implicated.
METHODS: Two resistant cellular variants, MCF-7Var-H and MCF-7Var-I, were generated by a novel strategy and their phenotype features were evaluated. Phenotypic assessment was performed by MTT assays, cytometry, immunofluorescence microscopy, zymography and protein expression analysis.
RESULTS: MCF-7Var-H, generated only with tamoxifen metabolites, showed a critical down-regulation in hormone receptors, augmented migration capacity, metalloprotease 9 extracellular medium excretion, and a mesenchymal morphology in contrast with native MCF-7, suggesting the transition towards Triple-negative breast cancer (TNBC) phenotype. In contrast, MCF-7Var-I which was generated in a high LDL media, showed only a slight upregulation in ER and other less noticeable metabolic adaptations. Results suggest a potential role of transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) in phenotypic differences observed among variants.
CONCLUSIONS: LDL high or low concentrations during Tamoxifen´s metabolites chemoresistance acquisition leads to different cellular mechanisms related to chemoresistance. A novel adaptative cellular response associated with Nrf2 activity could be implicated.
摘要：
目的：雌激素受体阳性（ER+）乳腺癌约占病例的80%，他莫昔芬是选择新辅助化疗。然而,很大比例的患者出现化学耐药性，妥协的恢复。临床证据表明，高血浆水平的低密度脂蛋白（LDL）可以促进癌症进展。本研究分析了LDL对初级血浆活性他莫昔芬代谢产物抗性获得的影响，4-羟基他莫昔芬（4OH-Tam）和4-羟基-N-去甲基-他莫昔芬（endoxifen），乳腺癌ER+细胞（MCF-7）。
方法：两种抗性细胞变体，MCF-7Var-H和MCF-7Var-I，通过一种新的策略产生，并评估了它们的表型特征。通过MTT测定进行表型评估，细胞术,免疫荧光显微镜，酶谱和蛋白质表达分析。
结果：MCF-7Var-H，仅由他莫昔芬代谢物产生，显示激素受体的关键下调，增强的迁移能力，金属蛋白酶9胞外介质排泄，和与天然MCF-7相反的间质形态，表明向三阴性乳腺癌（TNBC）表型的转变。相比之下,MCF-7Var-I在高LDL培养基中产生，仅显示ER的轻微上调和其他不太明显的代谢适应。结果表明转录因子核因子红系2相关因子2（Nrf2）在变体之间观察到的表型差异中的潜在作用。
结论：在他莫昔芬代谢产物化学抗性获取过程中，高或低浓度的LDL会导致与化学抗性相关的不同细胞机制。可能涉及与Nrf2活性相关的新型适应性细胞应答。
方法：两种抗性细胞变体，MCF-7Var-H和MCF-7Var-I，通过一种新的策略产生，并评估了它们的表型特征。通过MTT测定进行表型评估，细胞术,免疫荧光显微镜，酶谱和蛋白质表达分析。
结果：MCF-7Var-H，仅由他莫昔芬代谢物产生，显示激素受体的关键下调，增强的迁移能力，金属蛋白酶9胞外介质排泄，和与天然MCF-7相反的间质形态，表明向三阴性乳腺癌（TNBC）表型的转变。相比之下,MCF-7Var-I在高LDL培养基中产生，仅显示ER的轻微上调和其他不太明显的代谢适应。结果表明转录因子核因子红系2相关因子2（Nrf2）在变体之间观察到的表型差异中的潜在作用。
结论：在他莫昔芬代谢产物化学抗性获取过程中，高或低浓度的LDL会导致与化学抗性相关的不同细胞机制。可能涉及与Nrf2活性相关的新型适应性细胞应答。
