Tirapazamine encapsulated hyaluronic acid nanomicelles realized targeted and efficient photo-bioreductive cascading cancer therapy

Currently,architecting a ratio nal and efficient nanoplatform combing with multi-therapeutic modalities is highly obligatory for advanced cancer treatment.In order to remedy the self-limiting hypoxic dilemma of photodynamic therapy(PDT),herein,a facile photosensitizer(i.e.,chlorin e6,Ce6) and bioreductive prodrug(i.e.,tirapazamine,TPZ)-coloaded hyaluronic acid(HA) nanomicelles(denoted as TPZ@HA-Ce6)was developed for the cascading mode of photo-bioreductive cancer therapy.Taking the typical advantage of Ce6 coupled HA conjugate,TPZ was easily and successfully accommodated into the hydrophobic core of HA-Ce6 nanomicelles,yielding TPZ@HA-Ce6.It showed good dispersibility and stability with the hydrodynamic size of ca.170 nm.It targeted the CD44 overexpressed cancer cells by receptor-mediated endocytosis way and killed them effectively with singlet oxygen and the subsequent TPZ radicals resulting from the oxygen depletion of PDT.The later was further verified by the hypoxia probe in vivo.Using murine mammary carcinoma 4 T1 model,TPZ@HA-Ce6 nanomicelles exhibited cascading and synergistic anticancer effect of PDT and TPZ bioreductive therapy compared with each monotherapy.This work suggests the promising prospect of the hybrid hyaluronic nanomicelles for highly efficient cancer combination treatment.

寡核苷酸Dbait乏氧辐射双诱导重组质粒的构建及其对人宫颈癌HeLa细胞的乏氧放射增敏效应

目的构建携带新型放射增敏剂Dbait的乏氧辐射双诱导的重组质粒pcDNA 3.1(+)-HREEgr-1-Dbait,探讨乏氧条件下其对宫颈癌HeLa细胞的放射增敏作用,为Dbait的基因靶向放射增敏治疗提供实验依据。方法从C57BL/6裸鼠肝组织扩增Egr-1启动子,人工合成HRE增强子序列和新型寡核苷酸药物Dbait,通过基因重组分别将Egr-1、HRE和Dbait克隆入pcDNA 3.1(+)中,获得重组质粒pcDNA 3.1(+)-HRE-Egr-1-Dbait。转染宫颈癌HeLa细胞,采用集落形成试验观察在常氧和乏氧状态下宫颈癌HeLa细胞的放射敏感度。结果真核表达重组质粒pcDNA 3.1(+)-HRE-Egr-1-Dbait构建成功并通过PCR和测序鉴定。在常氧情况下宫颈癌HeLa细胞的D_0、D_q、SF2、α/β值分别为1.98、0.93、0.52、11.12。在乏氧情况下宫颈癌HeLa细胞的D_0、D_q、SF2、α/β值分别为1.74、1.46、0.43、15.82,氧增敏比OER为0.88。结论成功构建了携带新型放射增敏剂Dbait的乏氧辐射双诱导的真核表达质粒pcDNA 3.1(+)-HRE-Egr-1-Dbait,并验证了其在宫颈癌HeLa细胞中的乏氧辐射增敏效应。

生物还原性药物与肿瘤治疗

概述国内外研究较多的几种生物还原性药物的酶作用机制、实验发展和用于肿瘤治疗的新型药物设计及其应用情况。

Phospholipid membrane-decorated deep-penetrated nanocatalase relieve tumor hypoxia to enhance chemo-photodynamic therapy

Hypoxia is a serious impediment to current treatments of many malignant tumors.Catalase,an antioxidant enzyme,is capable of decomposing endogenous hydrogen peroxide(H2O2)into oxygen for tumor reoxygenation,but suffered from in vivo instability and limited delivery to deep interior hypoxic regions in tumor.Herein,a deep-penetrated nanocatalase-loading DiIC18(5,DiD)and soravtansine(Cat@PDS)were provided by coating catalase nanoparticles with PEGylated phospholipids membrane,stimulating the structure and function of erythrocytes to relieve tumor hypoxia for enhanced chemophotodynamic therapy.After intravenous administration,Cat@PDS preferentially accumulated at tumor sites,flexibly penetrated into the interior regions of tumor mass and remarkably relieved the hypoxic status in tumor.Notably,the Cat@PDS+laser treatment produced striking inhibition of tumor growth and resulted in a 97.2%suppression of lung metastasis.Thus,the phospholipids membrane-coated nanocatalase system represents an encouraging nanoplatform to relieve tumor hypoxia and synergize the chemophotodynamic cancer therapy.

Immune therapies in pancreatic ductal adenocarcinoma: Where are we now?

Pancreatic ductal adenocarcinoma(PDAC)is one of the deadliest cancers,mostly due to its resistance to treatment.Of these,checkpoint inhibitors(CPI)are inefficient when used as monotherapy,except in the case of a rare subset of tumors harboring microsatellite instability(<2%).This inefficacy mainly resides in the low immunogenicity and non-inflamed phenotype of PDAC.The abundant stroma generates a hypoxic microenvironment and drives the recruitment of immunosuppressive cells through cancerassociated-fibroblast activation and transforming growth factorβsecretion.Several strategies have recently been developed to overcome this immunosuppressive microenvironment.Combination therapies involving CPI aim at increasing tumor immunogenicity and promoting the recruitment and activation of effector T cells.Ongoing studies are therefore exploring the association of CPI with vaccines,oncolytic viruses,MEK inhibitors,cytokine inhibitors,and hypoxia-and stroma-targeting agents.Adoptive T-cell transfer is also under investigation.Moreover,translational studies on tumor tissue and blood,prior to and during treatment may lead to the identification of biomarkers with predictive value for both clinical outcome and response to immunotherapy.

Inhibition of hypoxia-inducible factor 1 with acriflavine sensitizes hypoxic tumor cells to photodynamic therapy with zinc phthalocyanine-encapsulating cationic liposomes

Photodynamic therapy （PDT） is a tumor treatment modality in which a tumor- localized photosensitizer is excited with light, which results in local production of reactive oxygen species, destruction of tumor vasculature, tumor hypoxia, tumor cell death, and induction of an anti-tumor immune response. However, pre-existing tumor hypoxia may desensitize tumors to PDT by activating the hypoxia-inducible factor 1 （HIF-1） survival pathway. Therefore, we hypothesized that inhibition of HIF-1 with acriflavine （ACF） would exacerbate cell death in human epidermoid carcinoma （A431） cells. PDT of A431 tumor cells was per- formed using newly developed and optimized PEGylated cationic liposomes containing the photosensitizer zinc phthalocyanine （ZnPC）. Molecular docking revealed that ACF binds to the dimerization domain of HIF-la, and confocal microscopy confirmed translocation of ACF from the cytosol to the nucleus under hypoxia. HIF-1 was stabilized in hypoxic, but not normoxic, A431 cells following PDT. Inhibition of HIF-1 with ACF increased the extent of PDT-induced cell death under hypoxic conditions and reduced the expression of the HIF-1 target genes VEGF, PTGS2, and EDN1. Moreover, co-encapsulation of ACF in the aqueous core of ZnPC-containing liposomes yielded an adjuvant effect on PDT efficacy that was comparable to non-encapsulated ACF. In conclusion, HIF-1 contributes to A431 tumor cell survival following PDT with liposomal ZnPC. Inhibition of HIF-1 with free or liposomal ACF improves PDT efficacy.

重组人血管内皮抑素在治疗头颈部恶性肿瘤中的应用进展

头颈部恶性肿瘤的治疗方式主要是以手术切除为主的综合序列治疗,但5年总生存率提高不足50%,如何进一步提高头颈部恶性肿瘤治疗成功率成为临床中亟待解决的问题。重组人血管内皮抑素是一种靶点为血管内皮细胞的抗血管生成靶向药物,具有一定的抑制肿瘤的作用。单独用药治疗恶性肿瘤并不明显优于放化疗,但联合放化疗,可以通过改变肿瘤内部血管分布,改善肿瘤内部缺氧,促使血管正常化增加放化疗效果,且不产生药物抵抗,在头颈部恶性肿瘤治疗中表现出一定的优势,有望成为一种新的肿瘤治疗方法。文献复习结果表明,重组人血管内皮抑素作用机制主要包括调节内皮细胞内外基质蛋白影响新生血管生成;作用于内皮细胞表面相关受体;逆转异常新生血管达到血管正常化;抑制低氧诱导因子,改善肿瘤区域缺氧状态;调控细胞周期,使更多的肿瘤细胞处于放射敏感期以及使血管正常化窗口增加放化疗效果。其在头颈部恶性肿瘤放化疗协同作用以及在晚期头颈部恶性肿瘤中应用效果良好,为临床医生提供一种继放化疗之后又一抗肿瘤方法。