Rapalogs induce non-apoptotic,autophagy-dependent cell death in HPV-negative TP53 mutant head and neck squamous cell carcinoma

TP53 is the most frequently mutated gene in head and neck squamous cell carcinoma (HNSCC). Patients with HPV-negative TP53 mutant HNSCC have the worst prognosis, necessitating additional agents for treatment. Since mutant p53 causes sustained activation of the PI3K/AKT/mTOR signaling pathway, we investigated the effect of rapalogs RAD001 and CCI-779 on HPV-negative mutTP53 HNSCC cell lines and xenografts. Rapalogs significantly reduced cell viability and colony formation. Interestingly, rapalogs-induced autophagy with no effect on apoptosis. Pretreatment with autophagy inhibitors, 3-methyladenine (3-MA) and ULK-101 rescued the cell viability by inhibiting rapalog-induced autophagy, suggesting that both RAD001 and CCI-779 induce non-apoptotic autophagy-dependent cell death (ADCD). Moreover, rapalogs upregulated the levels of ULK1 and pULK1 S555 with concomitant downregulation of the mTORC1 pathway. However, pretreatment of cells with rapalogs prevented the ULK-101-mediated inhibition of ULK1 to sustained autophagy, suggesting that rapalogs induce ADCD through the activation of ULK1. To further translate our in vitro studies, we investigated the effect of RAD001 in HPV-negative mutTP53 (HN31 and FaDu) tumor cell xenograft model in nude mice. Mice treated with RAD001 exhibited a significant tumor volume reduction without induction of apoptosis, and with a concomitant increase in autophagy. Further, treatment with RAD001 was associated with a considerable increase in pULK1 S555 and ULK1 levels through the inhibition of mTORC1. 3-MA reversed the effect of RAD001 on FaDu tumor growth suggesting that RAD001 promotes ACDC in HPV-negative mutTP53 xenograft. This is the first report demonstrating that rapalogs promote non-apoptotic ADCD in HPV-negative mutTP53 HNSCC via the ULK1 pathway. Further studies are required to establish the promising role of rapalogs in preventing the regrowth of HPV-negative mutTP53 HNSCC.     

MTDH基因和ATG7基因在结直肠癌中的表达及临床意义

目的探讨异黏蛋白(MTDH)基因和自噬相关基因7 (ATG7)在结直肠癌(CRC)中的表达及临床意义。方法选取66例CRC患者的CRC组织及癌旁组织,比较CRC组织及癌旁组织中的MTDH mRNA和ATG7mRNA的相对表达量;比较不同临床特征CRC患者的CRC组织/癌旁组织MTDH mRNA、ATG7 mRNA的相对表达量;采用受试者工作特征(ROC)曲线分析CRC组织/癌旁组织中MTODH mRNA和ATG7 mRNA对结直肠癌的诊断价值,并分析MTDH mRNA与ATG7 mRNA的相关性。结果 CRC组织中MTDH mRNA和ATG7 mRNA相对表达量显著高于癌旁组织(P <0.01);TNM分期为Ⅲ~Ⅳ和有肝转移的CRC患者中,CRC组织/癌旁组织中的MTDH mRNA和ATG7 mRNA相对表达量均显著高于Ⅰ~Ⅱ期和无肝转移的CRC患者,低分化程度的CRC患者中CRC组织/癌旁组织中的MTDH mRNA和ATG7 mRNA相对表达量最高(P <0.01)。ROC曲线分析结果 CRC组织/癌旁组织中MTDH mRNA、ATG7 mRNA的AUC面积分别是0.934、0.900,诊断敏感度分别为90.91%、89.39%,特异度分别为86.37%、84.35%。Pearson分析结果表明CRC中MTDH的表达与ATG7的表达呈正相关(r=0.372,P=0.002)。结论 CRC组织中MTDH mRNA、ATG7 mRNA的表达高于癌旁组织。CRC组织中MTDH mRNA、ATG7 mRNA与TNM分期、分化程度、伴肝转移相关。CRC组织中MTDH mRNA、ATG7 mRNA具有诊断价值且两者具有正相关。     

蟾蜍灵诱导人宫颈癌C33A细胞自噬作用的机理研究

目的:探讨蟾蜍灵诱导人宫颈癌C33A细胞自噬的作用。方法:不同浓度梯度的蟾蜍灵处理人宫颈癌C33A细胞，选用CCK－8法检测蟾蜍灵对人宫颈癌C33A细胞的杀伤作用。透射电镜观察给药后C33A细胞的自噬现象。流式细胞仪检测细胞内活性氧（ROS）水平，蛋白免疫印迹法检测自噬LC3蛋白表达及相关信号通路JNK、p-JNK蛋白表达。结果:蟾蜍灵对人宫颈癌C33A细胞的生长抑制作用呈时间-剂量依赖性。蟾蜍灵给药后可诱导C33A细胞发生自噬，蛋白印迹实验结果表明LC3蛋白表达随药物浓度升高而增加。蟾蜍灵诱导C33A细胞自噬发生与其促ROS水平升高激活了JNK信号通路有关。结论:蟾蜍灵诱导C33A细胞自噬的机制可能与通过ROS/JNK通路促进细胞自噬有关，以此发挥其抗肿瘤的作用。     

自噬在前列腺癌发生发展和治疗中的研究进展

自噬是真核细胞通过溶酶体对其自身生物大分子和细胞器回收再利用的过程，其在维持细胞稳态中发挥重要作用，并参与多种病理生理过程。在肿瘤的发病过程中，自噬发挥“双面作用”，既可以抗癌也能促癌。前列腺癌是老年男性最常见的恶性肿瘤，研究表明前列腺癌的发生发展与自噬作用密切相关，放化疗、内分泌治疗等对肿瘤细胞造成的应激可通过自噬得以缓解，抵抗治疗，因而自噬抑制剂对于放化疗等具有协同促进作用。本文就自噬在前列腺癌中发病和治疗进行综述，以期为前列腺癌的诊治提供一些新的思路。     

Survivin-shRNA对视网膜母细胞瘤HXO-RB44细胞自噬及凋亡的影响

目的:研究Survivin-shRNA对视网膜母细胞瘤HXO-RB44细胞自噬及凋亡的影响。方法:培养视网膜母细胞瘤HXO-RB44细胞，构建Survivin-shRNA载体。按照处理不同分为Survivin-shRNA组、GFP组和CON组。分别采用流式细胞术检测Survivin-shRNA对HXO-RB44细胞凋亡和细胞周期的影响，应用MTT法检测Survivin-shRNA对HXO-RB44细胞活性的影响，Western blot法检测Survivin-shRNA对HXO-RB44 细胞自噬相关蛋白LC3、p62 与mTOR 表达的影响。结果:流式细胞术结果表明，与Control组和GFP组相比，Survivin-shRNA组细胞凋亡率增加，差异有统计学意义（P＜0.05）；随着作用时间的延长，S期出现阻滞，48 h阻滞最强，显著高于对照组（P＜0.05）。MTT结果发现Survivin-shRNA可抑制HXO-RB44细胞增殖活性，与Control组和GFP组相比，差异有统计学意义（P＜0.05）；Western blot结果发现，与对照组相比，LC3表达量显著增加（P＜0.01）；而mTOR表达量降低（P＜0.01）。结论:Survivin-shRNA可促进视网膜母细胞瘤HXO-RB44细胞的凋亡和自噬水平，进而特异性杀伤肿瘤细胞。     

自噬性细胞死亡研究进展

自噬性细胞死亡（autophagic cell death）为Ⅱ型程序性细胞死亡,同细胞凋亡（Ⅰ型程序性细胞死亡）一样被发现多年，但近些年才引起人们的关注。现已证实自噬性细胞死亡是除细胞凋亡外另一重要的死亡调控机制。自噬性细胞死亡在参与细胞存活、分化、增殖和衰老的同时还可能参与多种疾病的发生发展，尤其与肿瘤及其电离辐射的关系越来越密切，因此研究自噬发生及调控的分子机制对于进一步了解自噬与疾病的关系，探索临床治疗方案具有重要的意义。本文就近些年自噬性细胞死亡的研究进展作一详细综述。     

Adaptive response of resistant cancer cells to chemotherapy

Despite advances in cancer therapeutics and the integration of personalized medicine, the development of chemoresistance in many patients remains a significant contributing factor to cancer mortality. Upon treatment with chemotherapeutics, the disruption of homeostasis in cancer cells triggers the adaptive response which has emerged as a key resistance mechanism. In this review, we summarize the mechanistic studies investigating the three major components of the adaptive response, autophagy, endoplasmic reticulum (ER) stress signaling, and senescence, in response to cancer chemotherapy. We will discuss the development of potential cancer therapeutic strategies in the context of these adaptive resistance mechanisms, with the goal of stimulating research that may facilitate the development of effective cancer therapy.