培美曲塞-磷脂偶联物修饰的靶向性舒尼替尼与长春瑞滨脂质体的研制及其在体外对耐药性乳腺癌的抑制效应

乳腺癌是女性最易罹患的疾病，而肿瘤多药耐药性通常是化疗失败的主要原因。本研究以培美曲塞（PMT）和DSPE-PEG2000-NH2为原料合成了新的靶向性偶联物DSPE—PEG2000．PMT，并将其修饰到脂质体表面，制备了同时包封有舒尼替尼与长春瑞滨的靶向性脂质体，以增强化疗药物对多药耐药性乳腺癌的治疗效果。经过质谱分析证实，合成的靶向性载体材料DSPE．PEG2000-PMT与目标产物相符。建立了可同时检测舒尼替尼和长春瑞滨含量的高效液相色谱分析方法，检测波长为215nm，柱温30℃，流动相为乙腈-0．05MKH2P04（pH3．5）-三乙胺（35：65：0．3，v／v／v）。舒尼替尼和长春瑞滨的最低检测浓度分别为25ng／mL和5ng／mL，最低定量浓度均为0．25μg／mL。两药在0．5-25．0μg／mL范围内线性良好。各脂质体包封率均大于90％，粒径均-（～90nm），Zeta电位略显负电性。在体外耐药乳腺癌MCF-7／Adr细胞中评价了靶向性舒尼替尼与长春瑞滨脂质体的抗增殖效应。结果显示，同对照组相比，靶向性舒尼替尼与长春瑞滨脂质体对MCF-7／Adr细胞具有最强的抑制增殖效应。以靶向性香豆素脂质体为荧光探针，考察了靶向性脂质体在耐药乳腺癌MCF-7／Adr细胞中的靶向性，同非靶向性制剂相比，靶向脂质体在耐药性癌细胞中摄取最多。因此，制备的靶向性舒尼替尼与长春瑞滨脂质体是-种新的靶向制剂，能够被耐药乳腺癌细胞靶向性摄取，可在体外显著抑制耐药性乳腺癌生长，从而为耐药乳腺癌的化学治疗提供了-种新的策略。

Development of targeted sunitinib plus vinorelbine liposomes modified with DSPE-PEG2000-pemetrexed conjugate and the inhibitory effect toresistant breast cancer in vitro

Multidrug resistance （MDR） of breast cancer is a major cause of failure in chemotherapy. In the present study, a distearoylphosphatidyl ethanolamine-polyethylene glycol-pemetrexed （DSPE-PEG2000-PMT） conjugate was synthesized from DSPE-PEG2000-NH2 and pemetrexed, and targeted sunitinib plus vinorelbine liposomes were developed by modifying DSPE-PEG20o0-PMT onto the surface of liposomes to overcome the MDR of breast cancer. The synthesized DSPE-PEG2000-PMT was confirmed to be consistent with the target product by matrix-assisted laser desorption/ionization time of flight mass spectrometry （MALDI-TOF-MS）. The concentrations of sunitinib and vinorelbine were measured simultaneously by high performance liquid chromatography （HPLC）. The analysis was performed on an ODS column at 30℃ at a wavelength of 215 nm with the mobile phase consisting of acetonitrile, 0.05 M KH2PO4 （pH 3.5） and triethylamine （35：65：0.3, v/v/v）. The limits of detection for sunitinib and vinorelbine were 25 ng/mL and 5 ng/mL, respectively, and the limits of quantification for both drugs were 0.25μg/mL. Two drugs were linearly correlated in the range of 0.5-25.0 μg/mL. For varying types of liposomes, the encapsulation efficiencies were 〉90%; the particle sizes were approximately 90 nm, and zeta potentials were slightly negative. The inhibitory effects were evaluated in the resistant breast cancer MCF-7/Adr cells. The results revealed that targeted sunitinib plus vinorelbine liposomes exhibited the strongest inhibitory effect to the resistant MCF-7/Adr cells among the varying formulations. Targeted coumarin liposomes were used as a fluorescent probe to evaluate the targeting effect to resistant breast cancer MCF-7/Adr cells. The results demonstrated that the targeted coumarin liposomes displayed the highest cellular uptake compared to non-targeted formulations. In conclusion, the targeted sunitinib plus vinorelbine liposomes represented a novel type of nano-formulations, which could accumulate in the resistant breast cancer cells, thereby inhibiting proliferation of the resistant cancer cells. Accordingly, the targeted sunitinib plus vinorelbine liposomes may provide a new strategy for circumventing the drug resistance in the resistant breast cancer.