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The clinical tumor therapy was greatly challenged due to the complex characteristics of tumor microenvironment, however, which also provide arena for novel therapeutic strategies. In this study, poly(2-ethyl-2-oxazoline)-poly(lactic acid)-SS-poly(β-amino ester (PEOz-PLA-SS-PBAE) triblock copolymers with pH and GSH double response were synthesized, polymer micelles were prepared by thin film hydration method for loading of silybin to improve its antitumor activity. The critical micelle concentration was determined by pyrene fluorescence method as 1.8 μg·mL-1. The particle size was 155.30 ± 1.80 nm as determined by dynamic light scattering, with polydispersity index of 0.168 ± 0.004. The drug loading and entrapment efficiency of the micelles were determined by HPLC as (5.48 ± 0.04)% and (68.52 ± 0.48)%, respectively. The in vitro drug release profiles showed that the micelles have low pH sensitivity and high GSH responsiveness, and exhibited sustained release profiles. The good biocompatibility of the material was proved by measuring the hemolysis rate and cytotoxicity of the blank micelle. The cytotoxicity and apoptosis rate of tumor cells showed that the drug loaded PEOz-PLA-SS-PBAE micelles had significant inhibitory effect and apoptosis-inducing effect on MDA-MB-231 cells. The results of wounding healing assay and Transwell invasion test showed that the drug loaded PEOz-PLA-SS-PBAE micelles could significantly inhibit the metastasis of MDA-MB-231 cells. The PEOz-PLA-SS-PBAE drug-loaded micelles prepared in this study have good inhibitory effect on tumor growth and anti-tumor metastasis in vitro, which lays the foundation for the further application of silybin.
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@#[摘 要] 目的：分析miR-19对PTEN及PI3K-Akt通路的调节作用，揭示miR-19和PTEN对子宫内膜癌KLE细胞侵袭、迁移的影响及其机制。方法：收集2017年5月至2020年8月河北医科大学第一医院收治的74例子宫内膜癌患者经手术切除（术前未接受放化疗等治疗）且病理确诊为子宫内膜癌的肿瘤组织及对应癌旁组织，采用qPCR和WB法检测PTEN在子宫内膜癌组织中的表达水平以及转染miR-19模拟物或抑制物对KLE细胞中PTEN表达的影响。通过TargetScan及双荧光素酶报告基因实验预测并验证PTEN是否为miR-19的靶基因，将KLE细胞随机分为对照（NC）组、miR-19模拟物组和miR-19+PTEN组，分别转染阴性对照片段（miR-NC）、miR-19模拟物或共转染miR-19模拟物+PTEN过表达载体，采用Transwell和细胞划痕实验检测miR-19和PTEN对KLE细胞迁移和侵袭能力的影响，WB法检测对PI3K-Akt通路相关蛋白表达的影响。结果：子宫内膜癌组织中PTEN的mRNA和蛋白表达水平均明显低于癌旁组织（均P<0.01）。miR-19能与PTEN mRNA的3’-UTR特异性结合，上调miR-19的表达能抑制PTEN的mRNA和蛋白的表达，下调miR-19的表达则出现相反的结果（均P<0.01）。与miR-NC组相比，miR-19 模拟物组的迁移、侵袭细胞数以及划痕愈合率均显著升高（均P<0.01），而miR-19+PTEN组的细胞迁移和侵袭能力以及划痕愈合率较miR-19摸拟物组则明显降低（均P<0.01）；与miR-NC组相比，miR-19模拟物组中PTEN蛋白的表达明显降低，而p-Akt 308和p-Akt 473蛋白的表达明显升高，Akt蛋白的表达无明显变化（均P<0.01）；而在miR-19+PTEN组中，p-Akt 308和p-Akt 473蛋白的表达均明显低于miR-19模拟物组（均P<0.01）。结论：miR-19可能通过抑制PTEN的表达从而活化PI3K-Akt通路，进而促进子宫内膜癌KLE细胞的迁移和侵袭。
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Objective: To investigate the pharmacokinetics and the distribution in tumor tissues of docetaxel nanomicelles. Method: The docetaxel nanomicelles was prepared by filming-rehydration method.HPLC was employed to determine the content of docetaxel in biological samples and the corresponding methodological evaluation was carried out.The mouse Lewis lung carcinoma model was established,when dosage of administration in tail vein was 20 mg·kg-1,and then the effect of free drug(DTX),non-pH-sensitive drug-loaded micelles(PELA-DTX) and pH-sensitive drug-loaded micelles(PBAE-DTX) on the pharmacokinetics and tissue distribution of tumor-bearing mice were investigated. Result: The docetaxel nanomicelles(PELA-DTX and PBAE-DTX) were successfully prepared.The method for the determination of docetaxel in mice was established by HPLC,the linearity,precision of the method and the recovery rate of samples all met the requirements.In the pharmacokinetic study,the plasma concentration of PBAE-DTX was always at a high level within 24 h.Compared with PELA-DTX and DTX,the areas under the curve(AUC0-∞) of PBAE-DTX were increased by 3.63% and 8.96%,the mean residence times(MRT) were extended by 2.86% and 6.43%,the half-life and the drug blood circulation time were prolonged.In the tissue distribution study,it was found that three docetaxel preparations were distributed in the heart,liver,spleen,lung,kidney and tumor tissue within 1 h after administration,but the distribution of these drugs in the tissues was reduced along with the extension of time,the accumulation of PBAE-DTX in tumor tissue was significantly higher than that in DTX and PELA-DTX at 24 h. Conclusion: PBAE-DTX can prolong the circulation time of docetaxel in the blood,increase its bioavailability,and significantly increase its distribution in tumor tissue.
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Docetaxel-loaded nanomicelles were prepared in this study to improve the solubility and tumor targeting effect of docetaxel(DTX),and further evaluate their anticancer effects in vitro. PBAE-DTX nanomicelles were prepared by film-hydration method with amphiphilic block copolymer polyethyleneglycol methoxy-polylactide(PELA) and pH sensitive triblock copolymer polyethyleneglycol methoxy-polylactide-poly-β-aminoester(PBAE) were used respectively to prepare PELA-DTX nanomicelles and PBAE-DTX nanomicelles. The nanomicelles were characterized by physicochemical properties and the activity of mice Lewis lung cancer cells was studied. The results of particle size measurement showed that the blank micelles and drug-loaded micelles had similar particle sizes, ranging from 10 to 100 nm. The particle size of PBAE micelles was changed under weak acidic conditions, with good pH response. The encapsulation efficiency of the above two types of DTX-loaded nanomicelles determined by HPLC was(93.8±1.70)% and(87.2±4.10)%, and the drug loading amount was(5.3±0.10)% and(4.9±0.05)%,respectively. Furthermore,the DTX micelles also showed significant inhibitory effects on Lewis lung cancer cells by MTT assay, and pH-sensitive PBAE-DTX showed better cytotoxicity. The results of flow cytometry indicated that,the apoptosis rate of lung cancer Lewis cells was(20.72±1.47)%,(29.71±2.38)%,and(40.91±1.90)%(P<0.05) at 48 h after treatment in DTX,PELA-DTX,and PBAE-DTX groups. The results showed that different docetaxel preparations could promote the apoptosis of Lewis cells, and PBAE-DTX had stronger apoptotic-promoting effect. The pH-sensitive DTX-loaded micelles are promising candidates in developing stimuli triggered drug delivery systems in acidic tumor micro-environments with improved inhibitory effects of tumor growth on Lewis lung cancer.