蜕膜化缺陷在子痫前期发病机制中的研究进展

子痫前期是一种严重影响孕产妇和胎儿健康的妊娠期高血压疾病。其病因和发病机制至今尚未阐明,如何有效地预测、诊断和治疗子痫前期,一直是妇产科学界关注的焦点。子宫内膜的蜕膜化为胚胎着床和胚胎发育提供必需的营养和免疫豁免基质。而蜕膜细胞的生物学功能（增殖、分化、凋亡、血管发生和能量代谢等）紊乱所致的蜕膜化缺陷,可影响滋养层细胞的侵袭、炎症抵抗、氧化应激及免疫保护,影响胚胎着床和妊娠维持,从而调控子痫前期的发生、发展。充分了解蜕膜细胞的生物学功能异常所致的蜕膜化缺陷在子痫前期发病机制中的作用,将有助于为预测及诊治子痫前期提供更多的理论依据。     

恶性肿瘤中泛素化修饰对Warburg效应调控机制的研究进展

泛素化和Warburg效应在肿瘤的发生发展中均发挥重要作用。肿瘤中泛素化修饰过程与糖酵解效应密切相关,即肿瘤细胞中的泛素化修饰作用能够调控Warburg效应相关的底物蛋白的表达水平,进而调控肿瘤进展和治疗耐药。本文着重讨论肿瘤细胞中蛋白质的泛素化修饰作用对Warburg效应的调控机制。     

lncRNA BCYRN1在结外NK/T细胞淋巴瘤糖酵解激活中的作用及其机制研究

目的 探讨长链非编码RNA（long non-coding RNA,lncRNA）BCYRN1在结外NK/T细胞淋巴瘤（extranodal NK/T- cell lymphoma,ENKTCL）糖酵解激活中的作用及其机制。方法 收集2010—2021年于首都医科大学附属北京同仁医院诊治的236例ENKTCL患者信息,分析空腹血糖（fasting blood glucose,FBG）与无疾病进展生存（progression-free survival,PFS）的相关性;采用qRT-PCR检测32例初诊ENKTCL患者组织中的BCYRN1含量并分析其与PFS的相关性。利用质粒转染法构建过表达BCYRN1（OE-BCYRN1组）和干扰BCYRN1（shBCYRN1组）的ENKTCL SNK-6细胞株,采用Screen QuestTM比色法检测葡萄糖摄取能力,用乳酸检测试剂盒检测乳酸的生成能力;采用qRT-PCR和Western blot法检测糖酵解关键分子PKM2、HIF-1α、SLC2A1、LDHA和PDK1的表达水平;分别添加蛋白合成抑制剂、溶酶体抑制剂或激活剂后观察BCYRN1对PKM2稳定性的影响。采用RNA pull-down和RNA结合蛋白免疫沉淀（RIP）实验判断BCYRN1与PKM2相互作用的模式。结果 236例ENKTCL患者中,高血糖组（FBG>5.6 mmol/L）49例,正常血糖组（FBG≤5.6 mmol/L）187例,高血糖组5年PFS率低于低血糖组（32.1% vs 63.7%,P<0.001）;BCYRN1高表达组3年PFS率低于低表达组（26.1% vs 82.5%,P=0.014）。干扰BCYRN1后,ENKTCL SNK-6细胞对葡萄糖的摄取量和乳酸生成水平均显著降低（均P<0.05）;过表达BCYRN1后,糖酵解关键分子PKM2、HIF-1α、SLC2A1、LDHA和PDK1的表达量均显著升高（均P<0.05）。应用蛋白合成抑制剂（放线菌酮）分别处理SNK-6细胞3 h和6 h后,OE-BCYRN1组中PKM2的降解比例均显著低于OE-CTRL组（均P<0.05）,而shBCYRN1组中PKM2的降解比例均显著高于shCTRL组（均P<0.05）。经溶酶体抑制剂（Leupeptin）处理后shBCYRN1+Leupeptin组的PKM2降解比例明显下降（P<0.01）;经溶酶体激活剂（6-Aminonicotinamide,6-AN）处理后OE-BCYRN1+6-AN组的PKM2降解比例显著增加（P<0.001）。RNA pull-down和RIP实验显示BCYRN1基因可与PKM2蛋白发生直接相互作用。结论 BCYRN1可能通过溶酶体途径上调PKM2表达而激活ENKTCL糖酵解途径。     

AKT-mediated enhanced aerobic glycolysis causes acquired radioresistance by human tumor cells

Background and purpose

Cellular radioresistance is a major impediment to effective radiotherapy. Here, we demonstrated that long-term exposure to fractionated radiation conferred acquired radioresistance to tumor cells due to AKT-mediated enhanced aerobic glycolysis.

Material and methods

Two human tumor cell lines with acquired radioresistance were established by long-term exposure to fractionated radiation with 0.5 Gy of X-rays. Glucose uptake was inhibited using 2-deoxy-d-glucose, a non-metabolizable glucose analog. Aerobic glycolysis was assessed by measuring lactate concentrations. Cells were then used for assays of ROS generation, survival, and cell death as assessed by annexin V staining.

Results

Enhanced aerobic glycolysis was shown by increased glucose transporter Glut1 expression and a high lactate production rate in acquired radioresistant cells compared with parental cells. Inhibiting the AKT pathway using the AKT inhibitor API-2 abrogated these phenomena. Moreover, we found that inhibiting glycolysis with 2-deoxy-d-glucose suppressed acquired tumor cell radioresistance.

Conclusions

Long-term fractionated radiation confers acquired radioresistance to tumor cells by AKT-mediated alterations in their glucose metabolic pathway. Thus, tumor cell metabolic pathway is an attractive target to eliminate radioresistant cells and improve radiotherapy efficacy.     

Glucose avidity of carcinomas

The cancer cell phenotype has been summarized in six hallmarks [D. Hanahan, R.A. Weinberg, The hallmarks of cancer, Cell 100 (1) (2000) 57-70]. Following the conceptual trait established in that review towards the comprehension of cancer, herein we summarize the basis of an underlying principle that is fulfilled by cancer cells and tumors: its avidity for glucose. Our purpose is to push forward that the metabolic reprogramming that operates in the cancer cell represents a seventh hallmark of the phenotype that offers a vast array of possibilities for the future treatment of the disease. We summarize the metabolic pathways that extract matter and energy from glucose, paying special attention to the concerted regulation of these pathways by the ATP mass-action ratio. The molecular and functional evidences that support the high glucose uptake and the "abnormal" aerobic glycolysis of the carcinomas are detailed discussing also the role that some oncogenes and tumor suppressors have in these pathways. We overview past and present evidences that sustain that mitochondria of the cancer cell are impaired, supporting the original Warburg's formulation that ascribed the high glucose uptake of cancer cells to a defective mitochondria. A simple proteomic approach designed to assess the metabolic phenotype of cancer, i.e., its bioenergetic signature, molecularly and functionally supports Warburg's hypothesis. Furthermore, we discuss the clinical utility that the bioenergetic signature might provide. Glycolysis is presented as the "selfish" pathway used for cellular proliferation, providing both the metabolic precursors and the energy required for biosynthetic purposes, in the context of a plethora of substrates. The glucose avidity of carcinomas is thus presented as the result of both the installment of glycolysis for cellular proliferation and of the impairment of mitochondrial activity in the cancer cell. At the end, the repression of mitochondrial activity affords the cancer cell with a cell-death resistant phenotype making them prone to malignant growth.     

异常代谢物与肿瘤免疫微环境的改造

代谢重编程是肿瘤常见的特征之一,受到细胞内在因素和肿瘤免疫微环境（TIME）中代谢物的调节。微环境中的肿瘤细胞与免疫细胞对营养物质的利用存在竞争关系,肿瘤细胞代谢活性增强会导致免疫细胞所需关键营养物质被过度消耗,并减少抑制肿瘤免疫的代谢副产物的产生和蓄积,进而导致免疫细胞功能障碍。TIME中的肿瘤细胞、免疫细胞和基质细胞均可通过代谢中间物或产物的消耗和分泌来改变TIME,而改造后的TIME亦可反过来影响这些细胞的功能。本文就TIME中的异常代谢物对其的改造进行简要综述,深入了解并揭示异常代谢物与TIME的关系,以期为肿瘤免疫治疗提供理论基础及新的思路。     

柠檬酸钠促胃癌MGC-803细胞凋亡的作用及机制研究

目的:探讨柠檬酸钠(SCT)促进胃癌MGC-803细胞凋亡的作用及机制。方法:胃癌MGC-803细胞分别经SCT(5、10、20 mmol/L)和5-FU(0.5 mmol/L)作用,以未处理的MGC-803为阴性对照,用流式细胞仪检测细胞周期分布及细胞凋亡率;比色法检测细胞内乳酸含量、磷酸果糖激酶1(PFK-1)活性及三磷酸腺苷(ATP)水平;Western blot检测细胞中Bcl-2、Bax、caspase-3及Cyt-c蛋白的相对表达量。结果:与阴性对照细胞比较,SCT处理的MGC-803细胞G2/M期阻滞与细胞凋亡明显增加;细胞内乳酸含量、PFK-1的活性和ATP水平均明显降低;细胞内Bcl-2的表达明显降低,而Bax、caspase-3和Cyt-c表达明显升高(均P0.05)。5-FU对MGC-803细胞乳酸含量、PFK-1的活性无明显影响(均P0.05),但其他作用与SCT相似。结论:SCT可促进MGC-803细胞凋亡,其作用可能与其抑制PFK-1的活性,降低糖酵解效率,并与线粒体凋亡通路的激活有关。     

The effects of repeated exposure to anoxia on intracellular calcium,glycogen and lactate in isolated ferret heart muscle

Isolated cardiac tissue from the ferret was repeatedly exposed to anoxia while perfused with glucose-containing Tyrode solution. In one series of experiments, papillary muscles were injected with aequorin to measure intracellular Ca²⁺. On the first exposure to anoxia, the Ca²⁺ transients often increased, but on subsequent exposures this increase disappeared and eventually the Ca²⁺ transients declined on exposure to anoxia. This decline in the Ca²⁺ transients could be converted back to an increase by a 1 h exposure to an elevated (×5) glucose concentration. Exposure of aerobic muscles to 10 mM lactic acid caused a similar increase in the Ca²⁺ transients to that seen in early exposures to anoxia. In a second series of experiments, performed on Langendorff-perfused hearts, measurements were made of glycogen concentration preceding, and lactate production during, exposures to anoxia. At a constant level of glucose, glycogen concentration and lactate production were found to decline on repeated exposures to anoxia, and both were increased after a period of elevated glucose and reduced stimulation frequency. These results suggest that the response of the Ca²⁺ transients to anoxia is dependent on the metabolic status of the muscle. The increase in the Ca²⁺ transients during an early eposure to anoxia may be a consequence of lactic acid production due to accelerated glycolysis. Repeated exposures to anoxia reduce glycogen concentration and lactate production and this reduces the rise in the Ca²⁺ transients.     

O2 consumption,aerobic glycolysis and tissue phosphagen content during activation of the NA+/K+ pump in rat portal vein

Oxygen consumption, lactate production and tissue contents of ATP, phosphocreatine (PCr) and lactate were measured following readdition of K⁺ to K⁺-depleted rat portal veins, in order to study the energy turnover associated with Na⁺/K⁺ pumping. During incubation in K⁺-free medium at 37° C spontaneous contractions disappeared in 10–20 min. Readdition of K⁺ (5.9 mM) after 40 min K⁺-free incubation caused hyperpolarization of the cell membrane for the first 5–10 min and then gradual depolarization with return of spontaneous action potentials and contractions by 10–20 min. During the first 4–6 min after K⁺ readdition aerobic lactate production was about doubled and then gradually returned to the original level (0.17 mol/min g) at about 20 min. The increase in glycolytic rate was prevented by 1 mM ouabain. In contrast, O₂ consumption (in K⁺-free medium, 0.38 mol/min g) rose by about 10% when K⁺ was added and this increase lasted about 5 min. By 8 min after K⁺ addition the increased glycolysis and oxidative phosphorylation had accounted for each about the same amount of extra ATP generation over that extrapolated from the steady rate before K⁺ addition. The average total increase in ATP turnover in the first 8 min was 15%. During this period there was no change in the cellular content of ATP, PCr, or extractable ADP. The results indicate that Na⁺/K⁺ pumping utilizes a relatively small share of the total energy turnover in the vascular smooth muscle but is to a large extent dependent on aerobic glycolysis and therefore a major site of carbohydrate usage.