薯蓣皂苷下调ABCC1表达对人肝癌细胞HepG2/ADM耐药的影响

目的:探究薯蓣皂苷对人肝癌细胞HepG2/多柔比星(ADM)耐药性的影响及其可能的作用机制。方法:采用含0,10,20,30,40,50μmol·L^-1薯蓣皂苷的培养液培养HepG2、HepG2/ADM细胞,CCK法检测细胞增殖抑制率;MTT检测薯蓣皂苷对HepG2/ADM细胞、HepG2细胞半抑制浓度(IC50)值的影响;流式细胞术检测HepG2、HepG2/ADM细胞摄取ADM的能力。薯蓣皂苷联合ABCC1抑制剂处理HepG2/ADM细胞,MTT检测细胞IC50值变化;流式细胞术检测细胞摄取ADM的能力、细胞凋亡情况,免疫印迹法检测细胞人多药耐药相关蛋白1(ABCC1)、半胱天冬酶(caspase-3)、B淋巴细胞瘤-2(bcl-2)、Bcl-2相关X蛋白(Bax)蛋白表达情况。结果:HepG2/ADM细胞中ABCC1蛋白表达显著高于HepG2细胞(P<0.05)。薯蓣皂苷0~30μmol·L^-1对HepG2/ADM细胞、HepG2细胞毒性小。随着薯蓣皂苷处理浓度的升高,HepG2/ADM细胞IC50值均降低,摄取ADM量明显升高,具有剂量依赖性(P<0.05)。薯蓣皂苷联合ABCC1抑制剂处理HepG2/ADM细胞后能够进一步降低细胞IC50,提高细胞ADM摄取量,加速细胞凋亡,上调caspase-3、Bax蛋白表达,下调ABCC1、bcl-2蛋白表达(P<0.05)。结论:薯蓣皂苷能够逆转HepG2/ADM细胞耐药性,逆转效果与作用剂量相关,其机制可能与下调ABCC1表达,诱导细胞凋亡有关。     

P21-activated kinase 5 plays essential roles in the proliferation and tumorigenicity of human hepatocellular carcinoma

Aim： To investigate the roles of P21-activated kinase 5 （PAK5） in proliferation and tumorigenicity of human hepatocellular carcinoma （HCC）.
Methods： HCC and matched paraneoplastictis tissue samples were obtained from 30 patients. Human HCC cell lines SMMC7721, HepG2, Hep3B, SK-HEP-1, Huh-7, and liver cell line HL-7702 were examined. The expression of PAK5 gene was studied using real-time qPCR and Western blotting. Cell proliferation was quantified with the MTT assay. Cell cycle was analyzed with flow cytometry. The
tumorigenicity of Lv-shRNA-transfected HepG2 cells was evaluated in BALB/cA nude mice.

Results： The mRNA level of PAK5 was significantly higher in 25 out of 30 HCC samples compared to the matched paraneoplastic
tissues. The HCC cell lines showed varying expression of PAK5 protein, and the highest level was found in the HepG2 cells. PAK5 gene silencing in HepG2 cells markedly reduced the cell proliferation and colony formation, and induced cell cycle arrest in the G1 phase. Furthermore, PAK5 gene silencing suppressed the tumor formation in nude mice, and significantly decreased the expression of HCC-related genes Cyclin D1 and beta-catenin.

Conclusion： PAK5 may play essential roles in the initiation and progression of human HCC. Thus, it may be an effective therapeutic target or perhaps serve as a clinical diagnostic or prognostic marker in human HCC.     

三萜皂苷Saxifragifolin D抑制人肝癌耐药细胞HepG2/ADM生长并诱导细胞凋亡作用研究

目的研究Saxifragifolin D(SD)对人肝癌耐药细胞HepG2/ADM的生长抑制及诱导凋亡作用。方法采用MTT法观察SD对HepG2/ADM细胞的增殖抑制作用,应用流式细胞仪分析SD对细胞周期的影响,AnnexinⅤ-FITC/PI双染检测凋亡细胞比率,JC-1染色观察SD对细胞内线粒体膜电位的影响,Western blot检测凋亡相关蛋白caspase-9,caspase-3和PARP的激活及c-Raf,MEK和ERK蛋白的表达和磷酸化水平。结果 SD可以明显抑制人肝癌耐药细胞HepG2/ADM的增殖。细胞周期检测发现SD诱导细胞产生亚二倍体凋亡峰,同时细胞凋亡率也由对照组的5.3%增加到34.8%和47.8%。线粒体膜电位检测结果显示SD导致细胞内线粒体膜电位的明显降低。Western blot检测结果表明caspase-9,caspase-3被激活,PARP被剪切活化,cytochrome C由线粒体释放至胞质,c-Raf、MEK和ERK蛋白的磷酸化水平降低。结论 SD可以抑制人肝癌耐药细胞HepG2/ADM增殖并诱导其凋亡,作用机制可能与线粒体功能障碍及抑制c-Raf/MEK/ERK通路的活化有关。     

黄芪甲苷逆转耐药肝癌细胞株HepG2/GCS多药耐药的研究

目的探讨黄芪甲苷对耐药肝癌细胞株HepG2/GCS多药耐药的逆转作用及可能机制。方法以噻唑蓝(MTT)法测定黄芪甲苷的细胞毒作用和处理前后肝癌细胞对阿霉素的敏感性变化,通过Westernblot法检测细胞GCS蛋白的表达。结果黄芪甲苷在实验浓度范围内对HepG2、HepG2/GCS细胞均无明显毒性;浓度为40μg/ml的黄芪甲苷可逆转HepG2/GCS细胞对阿霉素的耐药性,逆转倍数为1.50,同时细胞内GCS蛋白的表达下降。结论黄芪甲苷具有逆转HepG2/GCS细胞多药耐药的作用,可能与下调细胞内GCS基因表达有关。     

阿霉素对裸小鼠人肝癌原位移植瘤多药耐药性的影响

目的　探讨阿霉素对裸小鼠原位移植人肝癌多药耐药性的影响 ,并研究其耐药机制。方法　人肝癌 (BEL 740 2 )裸小鼠原位移植 ,用阿霉素腹腔注射诱导耐药 ,经MTT法检测原代培养的耐药细胞对抗癌药的敏感性 ,以流式细胞仪检测癌细胞表面mdr1基因产物P170的表达及功能。以裸小鼠原位移植人肝癌模型观察阿霉素对耐药组的疗效。结果　移植瘤组织形态及生物学方面符合人肝癌特征 ,耐药细胞表面P170表达为 75 45 %± 5 6 7% ,而对照组表达仅 4 2 5 %± 1 2 8% (P <0 0 1) ,对阿霉素的耐药倍数提高了 16 7倍 ,对羟基喜树碱和表阿霉素具有交叉耐受性(13 7倍和 7 5倍 )。耐药细胞表面P170有较强的药物外排功能。诱导后的肝癌在体内对阿霉素获得了明显的抗性。结论　阿霉素较易诱导原位移植于裸小鼠的人肝癌多药耐药性的产生 ,耐药机制主要与P170的过度表达有关     

Involvement of miR-133a and miR-326 in ADM resistance of HepG2 through modulating expression of ABCC1

Recent studies have shown that a class of small, functional RNAs, named microRNAs, may regulate multidrug resistance-associated protein 1 (ABCC1). Since ABCC1 is an important efflux transporter responsible for cellular drug disposition, the discovery of microRNAs (miRNA) brings an idea that there may be some other unknown multidrug resistance (MDR) mechanisms exist. Using computational programs, we predicted that the 3′untranslated region (3′UTR) of ABCC1 contains a potential miRNA binding site for miR-133a and also two other for miR-326. These binding sites were confirmed by luciferase reporter assay. ABCC1 mRNA degradation was accelerated dramatically in cells transfected with miR-133a or miR-326 mimics using qRT-PCR, Furthermore, western blot analysis indicated that ABCC1 protein expression was significantly down-regulated in hepatocellular carcinoma cells line HepG2 after transfection with miR-133a or miR-326 mimics, suggesting the involvement of mRNA degradation and protein expression mechanism. The effects of the two miRNAs on adriamycin (ADM) sensitivity to HepG2 cells were determined by MTT assay. Compared with mock transfection, miR-133a or miR-326 mimics transfection sensitized these cells to ADM. These findings for the first time demonstrated that the involvement of miR-133a and miR-326 in MDR is mediated by ABCC1 in hepatocellular carcinoma cell line HepG2 and suggested that miR-133a and miR-326 may be efficient agents for preventing and reversing ADM resistance in cancer cells.     

五味子甲素协同吉西他滨抑制肝癌细胞HepG2增殖

目的探究五味子甲素(deoxyschizandrin)联合吉西他滨(gemcitabin,GEM)对肝癌细胞HepG2增殖的影响及其可能的作用机制。方法CCK8法和克隆平板实验检测五味子甲素单药、GEM单药及联合用药对肝癌细胞HepG2增殖能力的影响;流式细胞术检测单药组及联合用药组中HepG2细胞的凋亡比例;Western blot法检测各组细胞中BCL2、BAX、pro-caspase3、cleaved-caspase3、pro-caspase9、cleaved-caspase9、β-catenin和TCF-4的表达。结果五味子甲素、GEM及联合用药对细胞HepG2的增殖均具有抑制作用,促进其凋亡,且联合用药组对HepG2细胞的作用明显强于单药组(P<0.05);Western blot结果表明,与对照组相比,五味子甲素、GEM和联合用药对pro-caspase3、pro-caspase9表达无明显影响,显著减少BCL2、β-catenin及TCF-4蛋白的表达(P<0.05),上调BAX、cleaved-caspase3、cleaved-caspase9蛋白的表达(P<0.05)。其中,联合用药比单药更为显著(P<0.05)。结论五味子甲素协同GEM抑制肝癌细胞HepG2中β-catenin/TCF-4通路,进而减少细胞增殖,诱导其凋亡。     

Hydrotropic Polymeric Mixed Micelles Based on Functional Hyperbranched Polyglycerol Copolymers as Hepatoma-Targeting Drug Delivery System

Mixed copolymer nanoparticles (NPs) self-assembled from β-cyclodextrin-grafted hyperbranched polyglycerol (HPG-g-CD) and lactobionic acid (LA)-grafted hyperbranched polyglycerol (HPG-g-LA) were applied as carriers for a hydrophobic antitumor drug, paclitaxel (PTX), achieving hepatocellular carcinoma-targeted delivery. The resulting NPs exhibited high drug loading capacity and substantial stability in aqueous solution. In vitro drug release studies demonstrated a controlled drug release profile with increased release at acidic pH. Remarkably, tumor proliferation assays showed that PTX-loaded mixed copolymer NPs inhibited asialoglycoprotein (ASGP) receptor positive HepG2 cell proliferation in a concentration-dependent manner in comparison with ASGP receptor negative BGC-823 cells. Moreover, the competition assay demonstrated that the small molecular LA inhibited the cellular uptake of the PTX-loaded mixed copolymer NPs, indicating the ASGP receptor-mediated endocytosis in HepG2 cells. In addition, the intracellular uptake tests by confocal laser scanning microscopy showed that the mixed copolymer NPs were more efficiently taken up by HepG2 cells compared with HPG-g-CD NPs. These results suggest a feasible application of the mixed copolymer NPs as nanocarriers for hepatoma-targeted delivery of potent antitumor drugs.     

糖皮质激素对人卵巢癌细胞系3AO增殖分化及对糖皮质激素受体表达的影响

目的：观察不同浓度地塞米松（Dex)对人卵巢癌细胞系（3AO）增殖及分化的影响及其对糖皮质激素受体（GR）的调节作用。方法：以不同浓度Dex处理3AO细胞,采用活细胞计数法观察细胞增殖,用氨基安替比林法测定碱性磷酸酶（AKP）活性;用酶联免疫法测定细胞标志抗原CA125水平的变化;用放射配体结合法测定GR的表达。结果：Dex对3AO细胞的增殖有抑制作用,同时伴有细胞形态的变化及AKP活性增高和CA125的表达下降。Dex对3AO细胞AKP活性的诱导作用可被RU486所阻断。在3AO细胞中存在糖皮质激素受体（GR）,Dex对GR结合活性有下调作用。结论：Dex对3AO细胞有增殖抑制和诱导分化作用,这种作用是通过GR来介导的。     

糖皮质激素对人卵巢癌细胞系3A0增殖分化及对糖皮质激素受体表达的影响(英文)

目的:观察不同浓度地塞米松(Dex)对人卵巢癌细胞系(3AO)增殖及分化的影响及其对糖皮质激素受体(GR)的调节作用.方法:以不同浓度Dex处理3AO细胞,采用活细胞计数法观察细胞增殖,用氨基安替比林法测定碱性磷酸酶(AKP)活性;用酶联免疫法测定细胞标志抗原CA125水平的变化;用放射配体结合法测定GR的表达.结果:Dex对3AO细胞的增殖有抑制作用,同时伴有细胞形态的变化及AKP活性增高和CA125的表达下降.Dex对3AO细胞AKP活性的诱导作用可被RU486所阻断.在3AO细胞中存在糖皮质激素受体(GR),Dex对GR结合活性有下调作用.结论:Dex对3AO细胞有增殖抑制和诱导分化作用,这种作用是通过GR来介导的.     

雄黄注射液体内外抗肿瘤作用研究

目的:初步探讨雄黄注射液的体内外抗肿瘤作用。方法:采用噻唑蓝(MTT)方法观察雄黄注射液对培养的人白血病细胞株K562,人肝癌细胞株HepG-2,人胃癌细胞株MGC-803,和小鼠Lewis肺癌细胞的增殖抑制作用;建立小鼠S180腹水型肉瘤模型,采用1、2、3mg/kg剂量雄黄注射液作用于小鼠模型,观察雄黄注射液体内抗肿瘤作用。结果:MTT法显示雄黄注射液对人白血病细胞株K562,人肝癌细胞株HepG-2,人胃癌细胞株MGC-803,和小鼠Lewis肺癌细胞增殖有一定的抑制作用;灌胃给予雄黄注射液对小鼠S180腹水型肉瘤生长有一定抑制作用。结论:雄黄注射液能够抑制培养的肿瘤细胞生长,灌胃给药对S180腹水型肉瘤细胞移植的模型小鼠肿瘤增殖有明显的抑制作用。     

mdr1反义寡核苷酸增强多药耐药肝癌细胞HepG2/ADM化疗敏感性的实验研究

目的：探讨在体外实验条件下mdr1反义寡核苷酸对多药耐药肝癌细胞株化疗敏感性的影响。方法以肝癌细胞HepG2/ADM为研究对象,设立mdr1反义寡核苷酸组和空白试剂组作对照,利用脂质体包载肿瘤耐药基因mdr1的反义寡核苷酸进行细胞转染,通过反转录聚合酶链反应（RT-PCR）、免疫印迹实验（Western blotting）分别检测mdr1基因mRNA和P-gp蛋白表达,通过MTT实验检测细胞转染前后对阿霉素（ADM）、顺铂（DDP）和5-氟尿嘧啶（5-FU）的化疗敏感性。结果 HepG2/AMD肝癌细胞经反义寡核苷酸处理后,mdr1 mRNA、P-gp蛋白表达水平均明显降低,对ADM、DDP 和5-FU的化疗敏感性明显增强。结论反义寡核苷酸能在体外有效增加肝癌细胞HepG2/ADM对化疗药物的敏感性。     

丹酚酸C诱导肝癌HepG2细胞有丝分裂阻滞及凋亡的研究

目的研究丹酚酸C(salvianolic acid C,SalC)的体外抗肿瘤细胞增殖作用及其分子机制。方法 MTT法检测Sal C对人肿瘤细胞的增殖抑制作用,流式细胞术检测细胞周期分布及细胞凋亡,Giemsa染色进行细胞有丝分裂的形态学观察,微管蛋白聚合实验检测Sal C对微管蛋白聚合活性的影响,比色法检测细胞中Caspase-3和Caspase-6的活性。结果丹酚酸C能抑制多种人肿瘤细胞增殖,其中对HepG2细胞的抑制作用较明显。流式细胞术分析发现Sal C使HepG2细胞阻滞于G2/M期并随作用时间延长出现明显的凋亡峰,细胞中Caspase-3和Caspase-6的活性升高。Gi-emsa染色提示HepG2细胞发生有丝分裂阻滞。Sal C能明显抑制微管蛋白的聚合。结论 Sal C具有抗肿瘤细胞增殖活性,通过抑制微管蛋白聚合诱导细胞有丝分裂阻滞从而诱导凋亡。     

Vascular endothelial growth factor immunoneutralization in combination with cisplatin reduces EAC tumor growth

In the present study, we evaluated the effects of a neutralizing anti-Vascular Endothelial Growth Factor (VEGF) polyclonal antibody on murine EAC tumor growth both in vitro and in vivo. Furthermore, we investigated if in the presence of effective VEGF blockade, a conventional chemotherapeutic drug Cisplatin could be effective, and if so would there be an additive effect of the combination regimen. An in vitro cell proliferation assay using MTT kit showed that VEGF antibody alone inhibited proliferation of EAC cells significantly in all the three time intervals (p<0.05). But cisplatin treatment in combination with VEGF antibody resulted in highly significant inhibition (p<0.001) of cell proliferation. Apoptosis assay by FACS analysis showed that VEGF antibody-cisplatin combination treatment induced apoptosis in cultured EAC cells. Intraperitoneal administration of VEGF antibody (100 mug/dose) and cisplatin (0.5 mg/kg/dose) combination was observed to be more effective in reducing tumor burden and increasing life span when compared to VEGF antibody or cisplatin treatment alone in EAC solid tumor bearing mice. In EAC ascites tumor model, all the three types of treatment inhibited tumor burden and increased life span, but the inhibition was less compared to EAC solid tumor bearing mice. VEGF antibody singly and in combination with cisplatin reduced neoangiogenesis and vascular hyperpermeability. However, it is clear from the results that the combination treatment had no additive effect in reducing vascular hyperpermeability. Serum VEGF was not reduced significantly after treatment in EAC ascites tumor bearing mice, whereas in EAC solid tumor bearing mice it was reduced significantly after treatment. The results clearly show that though alone cisplatin showed antitumor efficacy but it had no significant inhibitory effect on neoangiogenesis and vascular hyperpermeability. Thus the present study suggests that anti-VEGF agent can be combined with traditional treatment modalities to ensure more effectiveness.     

RAD51AP1沉默通过调控有丝分裂基因抑制肝癌细胞增殖

目的 分析沉默RAD51AP1基因对肝癌细胞增殖的影响,并初步探索其作用机制。方法 利用qPCR检测RAD51AP1在不同肝癌细胞系中的表达;制备shRAD51AP1慢病毒并转导HepG2和Huh7细胞来沉默RAD51AP1,采用qPCR检测RAD51AP1的沉默效率;MTS法和克隆形成实验检测RAD51AP1沉默对细胞增殖和克隆形成能力的影响;根据转录组测序结果筛选出差异表达基因,并作进一步的检测分析;通过裸鼠体内成瘤实验研究RAD51AP1沉默对肝癌细胞增殖的影响。结果 MTS结果显示,HepG2和Huh7细胞中RAD51AP1沉默组的增殖能力均显著低于对照组（P<0.01）;克隆形成实验显示,RAD51AP1沉默组克隆形成数明显少于对照组（P<0.01）;通过转录测序筛选出差异表达基因TACC1、NEK7,并从蛋白水平进行了验证。结论 RAD51AP1基因沉默能够有效抑制肝癌细胞增殖,有望成为预防或治疗肝癌的新靶点。     

Methotrexate and 5-aminoimidazole-4-carboxamide riboside exert synergistic anticancer action against human breast cancer and hepatocellular carcinoma

Aim:

To investigate the influences of methotrexate (MTX) on the anticancer actions and pharmacokinetics of 5-aminoimidazole-4-carboxamide riboside (AICA riboside) in human breast cancer and hepatocellular carcinoma.

Methods:

Human breast cancer cell line MCF-7 and human hepatocellular carcinoma cell line HepG2 were examined. The cell proliferation was assessed using a sulforhodamine B assay. Western blotting and radioactivity assays were used to analyze the phosphorylation of AMPK. The DNA synthesis was analyzed with BrdU incorporation. Nude mice bearing MCF-7 cell xenografts were used to for in vivo study. MTX (50 mg/kg, ip, per week) and AICA riboside (200 mg/kg, ip, every other day) were administered the animals for 2 weeks. The concentrations of AICA riboside and its active metabolite AICA ribotide in the plasma and tumors were measured with HPLC.

Results:

Synergistic cytotoxicity in vitro was observed with MTX (0.1, 0.5, and 1 μmol/L) combined with AICA riboside (0.25–1 mmol/L) in MCF-7 cells, and with MTX (0.5 and 1 μmol/L) combined with AICA riboside (0.5 and 1 mmol/L) in HepG2 cells. MTX (1 μmol/L) significantly enhanced the AICA riboside-induced AMPK activation and BrdU incorporation in both MCF-7 and HepG2 cells. Co-treatment with MTX and AICA riboside exerted more potent inhibition on the tumor growth in nude mice than either drug alone. After injection of AICA riboside (200 mg/kg, iv) in nude mice bearing MCF-7 xenografts, MTX (50 mg/kg, iv) significantly increased the concentrations of AICA riboside and its active metabolite AICA ribotide in tumors.

Conclusion:

MTX and AICA riboside exert synergistic anticancer action against MCF-7 and HepG2 cells in vitro and in vivo. MTX increases the concentration of AICA riboside and its active metabolite AICA ribotide in tumors in vivo.     

miR-506 对肝癌细胞恶性表型的影响

摘要:目的 探讨微 RNA-506（microRNA-506,miR-506）对肝癌细胞活性、 增殖和侵袭等恶性表型的调控作 用。方法 以肝癌细胞系 HepG2 和 QGY-7703 为模型, 依处理方式不同分别分为细胞常规培养 （细胞对照） 组、 pcD⁃ NA3 空载体对照组、 转染 pcDNA3/pri-506 过表达 miR-506 （过表达 miR-506） 组、 pSIH1 空载体对照组及转染 pSIH1/ TuD-506 抑制 miR-506 （抑制 miR-506） 组。实时定量逆转录 PCR 检测细胞内 miR-506 的表达水平。分别用 CCK- 8 实验、 体外集落形成实验和 Transwell 侵袭实验检测各组细胞的活性、 集落形成能力和侵袭能力。结果 在肝癌细 胞系 HepG2 和 QGY-7703 中, 与对应的空载体对照组相比, 过表达 miR-506 组的细胞内 miR-506 表达水平升高, 而 抑制 miR-506 组的细胞内 miR-506 表达水平降低（P＜0.05）; 过表达 miR-506 组细胞活性降低且形成集落的数量 和穿过 Transwell 微孔的细胞数量均减少, 而抑制 miR-506 组细胞活性升高且形成集落的数量和穿过 Transwell 微孔 的细胞数量均明显增加（P＜0.05）。与细胞对照组相比, pcDNA3 空载体对照组和 pSIH1 空载体对照组均不影响以 上各指标 （P＞0.05）。结论 miR-506 抑制肝癌细胞的活性、 集落形成能力和侵袭能力等恶性表型, 在肝癌细胞中发 挥抑癌基因的作用。     

雷帕霉素对肝癌化疗的增敏作用及相关机制研究

目的探讨雷帕霉素(rapamycin)对阿霉素(DOX)治疗肝癌效果的影响以及相关机制。方法 DOX单独或与rapamycin联合处理HepG2、Hep3B 2种肝癌细胞48 h,用MTT法测定细胞的增殖情况;DOX、rapamycin以及两者联合处理HepG2、Hep3B细胞24 h,以流式细胞术检测细胞凋亡率,用Western blot法检测PI3K/Akt/mTOR通路相关蛋白(p-Akt、p-mTOR、p21和p53)的表达。结果 DOX能浓度依赖性抑制HepG2和Hep3B细胞的增殖,且对HepG2细胞的抑制作用明显强于Hep3B细胞;与单用DOX比较,DOX与rapamycin联用对2种细胞增殖的抑制作用明显增加,且增加Hep3B细胞对DOX敏感性的作用尤为显著。DOX作用HepG2和Hep3B细胞24 h,可诱导2种细胞发生不同程度的凋亡,rapamycin单独作用的促凋亡作用不明显,但与DOX联用后能明显增加DOX的促凋亡作用,2种细胞的凋亡率均明显增加。Western blot结果显示,rapamycin能明显上调p-Akt、p21和下调p-mTOR在2种细胞的表达水平,轻度上调p53在HepG2中的表达;DOX能轻度上调p-Akt、p21和下调p-mTOR在2种细胞的表达水平,明显上调p53在HepG2中的表达,Hep3B中无p53表达;两药合用对上述蛋白表达的影响有协同作用。结论 rapamycin能增加DOX对不同p53状态肝癌细胞的增殖抑制和促凋亡作用及肝癌对DOX化疗的敏感性,其机制可能与rapamycin激活凋亡的p53和不依赖p53的p21途径有关。