Inhibition Mechanism of Hydroxyproline-like Small Inhibitors to Disorder HIF-VHL Interaction by Molecular Dynamic Simulations and Binding Free Energy Calculations

Protein-protein interactions are vital for a wide range of biological processes.The interactions between the hypoxia-inducible factor and von Hippel Lindau(VHL)are attractive drug targets for ischemic heart disease.In order to disrupt this interaction,the strategy to target VHL binding site using a hydroxyproline-like(pro-like)small molecule has been reported.In this study,we focused on the inhibition mechanism between the pro-like inhibitors and the VHL protein,which were investigated via molecular dynamics simulations and binding free energy calculations.It was found that pro-like inhibitors showed a strong binding affinity toward VHL.Binding free energy calculations and free energy decompositions suggested that the modification of various regions of pro-like inhibitors may provide useful information for future drug design.

An inhibitor of HIF-α subunit expression suppresses hypoxiainduced dedifferentiation of human NSCLC into cancer stem cell-like cells

AIM:To investigate whether hypoxia induces dedifferentiation of non-small cell lung cancer(NSCLC) cells and whether a hypoxia-inducible factor(HIF) inhibitor is able to suppress the process.METHODS:Human lung adenocarcinoma A549 cells and squamous carcinoma QG56 cells were cultured under normoxic(21%O_2) or hypoxic(4%or 1%O_2) conditions.The expression of the following genes were examined by reverse transcription-polymerase chain reaction,Western blotting and/or immunofluorescence:HIF-1α and HIF-2αsubunits;differentiation marker genes,namely surfactant protein C(SP-C)(type Ⅱ alveolar cell marker),CC10(type I alveolar cell marker) and aquaporin 5(AQP5)(Clara cell marker);and stem cell-associated genes,namely CD133,0CT4,and Musashi-1(MSI1).The tumor sphere-forming ability of the cells was evaluated by culturing them in serum-free growth factor-rich medium containing epidermal growth factor(EGF) and fibroblast growth factor(FGF).CD133 expression in hypoxic regions in A549 tumors was examined by double-immunostaining of tissue cryosections with an anti-2-nitroimidazole EF5 antibody and an anti-CD133 antibody.The metastatic ability of A549 cells was examined macroscopically and histologically after injecting them into the tail vein of immunocompromised mice.RESULTS:A549 cells primarily expressed SP-C,and QG56 cells expressed CC10 and AQP5.Exposure of A549 cells to hypoxia resulted in a marked downregulation of SP-C and upregulation of CD133,OCT4,and MSI1 in a time-dependent manner.Moreover,hypoxia mimetics,namely desferrioxamine and cobalt chloride,elicited similar effects.Ectopic expression of the constitutively active HIF-la subunit also caused the downregulation of SP-C and upregulation of CD133 and MSI1 but not OCT4,which is a direct target of HIF-2.Hypoxia enhanced the sphere-forming activity of A549 cells in serum-free medium containing EGF and FGF.Similarly,hypoxia downregulated the expression of CC10 and AQP5 genes and upregulated CD133,OCT4,and MSI1 genes in QG56 cells.TX-402(3-amino-2-quinoxalinecarbonitrile 1,4-dioxide),which is a small molecule inhibitor of the expression of HIF-1α and HIF-2αsubunits under hypoxic conditions,inhibited the upregulation of SP-C'and hypoxia-induced down-regulation of CD133,OCT4,and MSI1.Notably,TX-402 significantly suppressed the hypoxia-enhanced lung-colonizing ability of A549 cells.CONCLUSION:Hypoxia induces the de-differentiation of NSCLC cells into cancer stem cell-like cells,and HIF inhibitors are promising agents to prevent this process.

低氧诱导因子脯氨酰羟化酶抑制剂对尿毒症透析患者心血管指标及心脑血管并发症影响研究

目的观察低氧诱导因子脯氨酰羟化酶抑制剂和重组人促红细胞生成素(r HuEPO)对尿毒症透析患者心血管指标和心脑血管并发症的影响。方法回顾性研究2022年1月1日至2022年12月31日期间于首都医科大学附属北京潞河医院肾内科服用罗沙司他的透析患者53例,按照1∶1的比例随机选取皮下注射rHuEPO的透析患者53例,比较两组患者基线及治疗12个月时血红蛋白(Hb)、血压及心血管指标,并比较治疗18个月间心脑血管并发症发生情况。结果两组基线资料及实验室检查指标差异无统计学意义(P>0.05)。治疗12个月时,两组Hb对比差异无统计学意义(P>0.05);与治疗前相比,两组Hb均显著升高,差异有统计学意义(P<0.05)。治疗12个月时,罗沙司他组夜间高血压比例低于对照组,左心室射血分数(LVEF)高于对照组,差异有统计学意义(P<0.05);与基线相比,治疗12个月后对照组夜间高血压比例、收缩压和舒张压升高,两组LVEF和白蛋白均升高,差异有统计学意义(P<0.05)。随访至18个月时,对照组发生心力衰竭比例高于罗沙司他组(χ^(2)=1.940,P=0.010)。多因素Cox回归分析发现使用rHuEPO是透析患者发生心脑血管并发症的独立危险因素(HR 2.22,95%CI 1.13~4.33,P=0.020)。结论与rHuEPO相比,罗沙司他对血压及心血管指标影响较小,可改善LVEF,降低透析患者血压升高及心脑血管并发症的发生风险。

肾性贫血的药物治疗进展

肾性贫血是慢性肾脏病的常见并发症,与慢性肾脏病患者预后密切相关。肾性贫血目前的治疗主要集中在促红细胞生成素替代和补充铁剂2个方面,临床上存在贫血患病率高、达标率低等问题。近年来,新兴的铁剂、促红细胞生成素制剂以及针对肾性贫血发病机制新靶点的治疗手段不断用于临床,为肾性贫血的治疗提供了新的选择。本文从肾性贫血的发病机制出发,综述了肾性贫血的药物治疗进展。