Balasso Anna, Salmaso Stefano, Pontisso Patrizia, Rosato Antonio, Quarta Santina, Malfanti Alessio, Mastrotto Francesca, Caliceti Paolo
Department of Pharmaceutical & Pharmacological Sciences, University of Padova, Via F. Marzolo 5, 35131 Padova, Italy.
Department of Medicine, University of Padova, via Giustiniani, 2, 35128 Padova, Italy.
Eur J Pharm Sci. 2017 May 30;103:104-115. doi: 10.1016/j.ejps.2017.02.016. Epub 2017 Feb 10.
A novel bioconjugate for hepatocellular carcinoma (HCC) targeting was obtained by pullulan re-programming, which involves the backbone oxidation and conjugation of targeting peptide and doxorubicin (Doxo) through a releasable linker. Preliminary in vivo studies showed that the oxidation of 40 glucopyranose units (GPU) out of 100 remarkably reduced the pullulan unspecific liver tropism. This oxidized polymer was functionalized with PreS1 to selectively target the HCC and with rhodamine (Rhod) as label to perform in vitro cell up-take investigations. PreS1 and Rhod were conjugated to the aldehydes present along the oxidized pullulan backbone through a 3.4 and 2kDa PEG spacer, respectively, and by reductive amination. The resulting PreS1-Pull-Rhod contained a mean of 8 PreS1 per oxidized pullulan chain. Cell culture studies were performed by using HepG2/SERPINB3 cells that overexpress the serpine B3 receptor and control HepG2/EMPTY cells that do not overexpress the receptor. A comparative study by cytofluorimetry and confocal microscopy performed using PreS1-Pull-Rhod and Pull-Rhod (control polymer) showed that PreS1 conveys to the conjugate high cell selectivity. Afterwards, the oxidized pullulan was exploited to generate a targeted drug delivery system by conjugation of Doxo to the polymer backbone through a hydrazone pH-sensitive bond and NH-PEG-PreS1. The PreS1-Pull-Doxo conjugate showed a two-fold increase of anticancer activity with respect to the control Pull-Doxo towards HepG2/SERPINB3 cells.
通过支链淀粉重新编程获得了一种用于靶向肝细胞癌（HCC）的新型生物共轭物，该过程涉及主链氧化以及通过可裂解连接子将靶向肽和阿霉素（Doxo）进行共轭。初步体内研究表明，100个葡萄糖吡喃糖单元（GPU）中有40个被氧化可显著降低支链淀粉的非特异性肝脏嗜性。这种氧化聚合物用前S1进行功能化以选择性靶向HCC，并使用罗丹明（Rhod）作为标记物进行体外细胞摄取研究。前S1和Rhod分别通过3.4 kDa和2 kDa的聚乙二醇（PEG）间隔臂并通过还原胺化反应与沿氧化支链淀粉主链存在的醛基共轭。所得的前S1-支链淀粉-Rhod每个氧化支链淀粉链平均含有8个前S1。细胞培养研究使用过表达丝氨酸蛋白酶抑制剂B3受体的HepG2/SERPINB3细胞和不表达该受体的对照HepG2/EMPTY细胞进行。使用前S1-支链淀粉-Rhod和支链淀粉-Rhod（对照聚合物）通过细胞荧光测定法和共聚焦显微镜进行的比较研究表明，前S1赋予共轭物高细胞选择性。之后，利用氧化支链淀粉通过腙pH敏感键和NH-PEG-前S1将Doxo与聚合物主链共轭，从而生成靶向药物递送系统。与对照支链淀粉-Doxo相比，前S1-支链淀粉-Doxo共轭物对HepG2/SERPINB3细胞的抗癌活性提高了两倍。
