重组腺病毒介导基质金属蛋白酶组织抑制因子-1对人肝癌HepG2细胞的影响与作用机制

目的探讨携带人基质金属蛋白酶组织抑制因子-1(hTIMP-1)的重组腺病毒(AdhTIMP-1)对人肝癌HepG2细胞增殖、侵袭、转移、凋亡以及瘤内血管生成的作用。方法构建AdhTIMP-1并感染人肝癌HepG2细胞,采用Boyden chamber检测细胞体外侵袭能力;感染AdhTIMP-1的HepG2细胞接种于裸鼠皮下观察其成瘤情况;建立荷瘤鼠模型,瘤内注射AdhTIMP-1,观察其对肿瘤生长的作用;处死荷瘤鼠,计数肺转移结节;CD34免疫组化观察肿瘤血管生成;原位末端标记(TUNEL)法检测肝癌细胞凋亡。结果AdhTIMP-1感染的HepG2细胞体外侵袭力下降91.4%,成瘤量下降75.8%,荷瘤鼠瘤体内注射AdhTIMP-1使肿瘤生长减少45.4%,组织血管密度减少47.8%,肺转移结节减少70.4%,肿瘤组织中细胞凋亡则增加了3倍。结论AdhTIMP-1能抑制肝癌HepG2细胞的侵袭、转移及瘤内血管形成,诱导肝癌细胞凋亡,可用于肝癌基因治疗的研究。     

脑源性神经营养因子对肝癌细胞株HepG2体外转移能力的影响

背景与目的:肝细胞性肝癌(hepatocellularcarcinoma,HCC)浸润转移是临床治疗失败的最常见原因,浸润转移的发生与癌细胞的生物学行为(迁移、侵袭、增殖)密不可分。近年来,人们已认识到脑源性神经营养因子(brainderivedneurotrophicfactor,BDNF)作为一种功能性蛋白特异地存在于HCC组织中,并与HCC的进展密切相关,但其确切功能不明。本实验初步探讨BDNF对肝癌细胞株HepG2体外迁移能力的影响及其机制。方法:采用MTT法观察BDNF对HepG2细胞增殖的作用,应用肿瘤细胞体外迁移实验和肿瘤细胞体外侵袭实验评价BDNF对HepG2细胞浸润转移能力的影响。采用RT-PCR法和Westernblot法分别从基因水平和蛋白水平检测HepG2细胞中BDNF特异性受体Tr!B的表达情况。结果:外源性的BDNF能有效促进HepG2细胞的增殖,在<100ng/ml的范围内,这一效应呈明显的浓度依赖性;经过50ng/ml和100ng/mlBDNF处理的HepG2细胞,迁移指数明显高于对照组(167vs.100,203vs.100,P<0.05);Transwell侵袭实验中,50ng/ml和100ng/mlBDNF组的每视野侵袭细胞数分别为167±38和215±51,与对照组(113±22)相比差异有显著性(P<0.05);较之正常肝细胞,HepG2细胞高表达Tr"B。结论:BDNF可调节肝癌细胞的生长、迁移与侵袭,是具有促进肝癌浸润转移的细胞因子。     

尼妥珠单抗联合表阿霉素对人肝癌细胞株ＨｅｐＧ２体外生长的影响

目的　观察尼妥珠单抗（ｈ-Ｒ３）与表阿霉素（ＥＰＩ）联合对人肝癌细胞株ＨｅｐＧ２体外生长及凋亡的影响。方法　选用浓度递增的ｈ-Ｒ３和ＥＰＩ,单独和联合作用于ＨｅｐＧ２细胞,ＭＴＴ法观察不同时间点、不同药物剂量对ＨｅｐＧ２细胞生长的影响,计算两者联合的ｑ值;流式细胞仪检测两种药物对ＨｅｐＧ２细胞凋亡率及细胞周期分布情况的影响。结果　ｈ-Ｒ３和ＥＰＩ单药对ＨｅｐＧ２细胞生长均有抑制作用且呈时间和剂量依赖性,两药单独作用７２ｈ后对ＨｅｐＧ２细胞生长的最高抑制率分别为（４９.５６±８.９３）％和（９２.９７±１.１９）％,两药联合对ＨｅｐＧ２细胞生长的最高抑制率为（６.４４±１.０）％,联合用药可提高细胞增殖抑制率,呈相加作用;流式细胞仪检测发现,联合组细胞凋亡率高于单药组,随时间增加凋亡率呈升高趋势;细胞周期检测提示ｈ-Ｒ３使细胞阻滞在Ｇ０／Ｇ１期,ＥＰＩ阻滞细胞在Ｓ期,两药均能影响细胞周期分布。结论　ｈ- Ｒ３在体外与ＥＰＩ联合可以提高对ＨｅｐＧ２细胞增殖抑制及凋亡的作用,两药均可影响ＨｅｐＧ２细胞周期的分布。     

FR/MA对HepG2肝癌细胞侵袭能力的影响

目的探讨金荞麦抗肿瘤提取物（FR）、苦参抗肿瘤提取物（MA）对肝癌细胞HepG2侵袭能力的影响及其可能作用机制。方法MTT法检测FR/MA单药及联合用药对HepG2细胞增殖的影响;Transwell侵袭小室测定法检测经FR/MA单药及联合用药处理过的细胞其侵袭能力的改变;RT-PCR分析侵袭转移相关基因nm23-H1、Tiam-1表达的变化。结果FR/MA单药及联合用药均能明显抑制HepG2的增殖,明显降低细胞侵袭能力。同时细胞内nm23-H1基因mRNA水平有不同程度的升高,而Tiam-1基因mRNA水平有不同程度的降低。结论FR和MA能够抑制HepG2侵袭,可能通过上调nm23-H1基因和下调Tiam-1基因的表达而发挥抗肿瘤侵袭作用。     

Ad-PTEN体外对SGC-7901胃癌细胞生长的抑制作用

目的:探讨腺病毒介导的PTEN基因表达体外对SGC-7901胃癌细胞生长抑制作用及其分子机制。方法:将携有PTEN基因的复制缺陷型腺病毒载体(Ad-PTEN)感染SGC-7901胃癌细胞,用RT-PCR法检测Ad-PTEN在细胞中的表达,光学显微镜及荧光显微镜下观察Ad-PTEN感染细胞前后形态的变化,MTT法检测Ad-PTEN对SGC-7901胃癌细胞生长的抑制作用,用流式细胞术(FCM)检测SGC-7901胃癌细胞凋亡率。RT-PCR分析Bax、Bcl-2、p53、Survivin细胞凋亡相关基因的表达。结果:Ad-PTEN基因组感染SGC-7901胃癌细胞后,RT-PCR结果显示PTEN目的基因能在SGC-7901胃癌细胞中转录,其表达可明显抑制该胃癌细胞的生长,并诱导细胞凋亡。其凋亡机制可能与Bax/Bcl-2比值、p53基因表达上调、Survivin下调有关。结论:重组腺病毒Ad-PTEN具有抑制SGC-7901胃癌细胞生长和诱导细胞凋亡的作用。     

Ad-PTEN体外对SGC-7901胃癌细胞生长的抑制作用

目的：探讨腺病毒介导的PTEN基因表达体外对SGC-7901胃癌细胞生长抑制作用及其分子机制。方法：将携有PTEN基因的复制缺陷型腺病毒载体（Ad-PTEN）感染SGC-7901胃癌细胞,用RT-PCR法检测Ad-PTEN在细胞中的表达,光学显微镜及荧光显微镜下观察Ad-PTEN感染细胞前后形态的变化,MTT法检测Ad-PTEN对SGC-7901胃癌细胞生长的抑制作用,用流式细胞术（FCM）检测SGC-7901胃癌细胞凋亡率。RT-PCR分析Bax、Bcl-2、p53、Survivin细胞凋亡相关基因的表达。结果：Ad-PTEN基因组感染SGC-7901胃癌细胞后,RT-PCR结果显示PTEN目的基因能在SGC-7901胃癌细胞中转录,其表达可明显抑制该胃癌细胞的生长,并诱导细胞凋亡。其凋亡机制可能与Bax/Bcl-2比值、p53基因表达上调、Survivin下调有关。结论：重组腺病毒Ad-PTEN具有抑制SGC-7901胃癌细胞生长和诱导细胞凋亡的作用。     

奥沙利铂对人肝癌细胞HepG2放射增敏作用初探

目的 观察奥沙利铂对人肝癌细胞HepG₂放射后增殖的影响。方法 采用MTT法测定不同浓度奥沙利铂作用HepG₂细胞不同时间后的细胞半数抑制浓度(IC₅₀)。选择合适的奥沙利铂浓度行细胞克隆形成实验,分别给予3种不同处理:HepG₂空白组、单纯照射组(1、2、4、6、8、10 Gy单次照射)、奥沙利铂+照射组)。同期选取6 Gy照射组检测细胞凋亡情况。检测以上3组细胞中细胞增殖蛋白ERK1/2和DNA损伤修复蛋白Ku-70表达情况。结果 奥沙利铂对HepG₂细胞的6、12、24、48 h的IC₅₀分别为54.4、29.1、17.8、10.5 mg/L。3 mg/L浓度奥沙利铂的放射增敏比为1.59。细胞凋亡情况检测结果表明奥沙利铂+照射组存活细胞比例均低于照射组(P=0.005)、奥沙利铂组(P=0.008)和空白对照组(P=0.001)。照射组和奥沙利铂+照射组的ERK1/2表达水平被持续抑制,其中照射组的ERK1/2表达水平在处理后48 h开始升高,但低于对照组,奥沙利铂+照射组的ERK1/2表达水平一直为最低,且没有升高趋势。各组Ku-70的变化水平与ERK1/2类似。结论 奥沙利铂对于人肝癌细胞HepG₂的体外放射具有显著的增敏作用。     

5-氮杂脱氧胞苷对肝癌细胞HepG2中抑癌基因FHIT表达的影响

背景与目的：肝癌细胞中由于FHIT基因过度甲基化而导致其表达降低。本实验应用甲基化酶抑制剂5-氮杂脱氧胞苷（5-Aza-2’deoxycytidine,5-Aza—dc）作用肝癌细胞株HepG2。观察用药后肝癌细胞中FHITmRNA和蛋白表达的变化,并观察5-Aza-dC对细胞增殖的影响。方法：以5-Aza—dC作用HepG2细胞．采用甲基化特异性聚合酶链反应（methylation—specific polymerase chain reaction,MSP）检测HepG2细胞中FHIT甲基化变化;采用RT-PCR检测FHITmRNA的表达：采用细胞免疫组织化学染色和Western blot方法检测FHIT蛋白表达,MTT法检测HepG2细胞增殖情况。结果：5-Aza—dC处理前,HepG2细胞FHIT基因呈甲基化状态,mRNA及蛋白表达缺失;经5-Aza—dC作用后,MSP显示HepG2细胞FHIT基因甲基化逆转：经1．0μmol／L、2．0μmol／L及4．0μmol／L的5-Aza—dC作用48h后,FHIT基因mRNA扩增出产物的吸光度值分别为0．80±0．32、1.41±0．54和1．51±0．61。Western blot检测产物积分灰度值分别为0．33±0．20、1．00±0．26和1．12±0．38：当药物浓度达到1．0μmol／L时出现了对HepG2细胞增殖的抑制作用。结论：5-Aza—dC能明显逆转HepG2细胞的FHIT基因异常甲基化,激活因高甲基化所致基因沉默的再转录,诱导该基因的表达;同时抑制细胞增殖。     

二甲双胍对人肝癌细胞HepG2增殖及乙酰辅酶A羧化酶影响的实验研究

目的 探讨二甲双胍在人肝癌细胞HepG2中的抗肿瘤活性及其作用机制。方法 选取二甲双胍不同浓度（0、1、5、10、15 mmol／L）处理HepG2细胞24、48及72 h,用CCK-8法检测其对细胞增殖的影响。设二甲双胍不同浓度（0、5、10、15 mmol／L）处理HepG2细胞72 h,用Western blotting检测腺苷酸活化蛋白激酶（AMPK）、P-AMPK、乙酰辅酶A羧化酶（ACC）、P-ACC蛋白表达,Real-time PCR检测ACC mRNA的表达水平。结果 二甲双胍对HepG2细胞的增殖抑制作用呈时间和浓度依赖性。经不同浓度二甲双胍处理HepG2细胞72 h后,P-AMPK蛋白表达随药物浓度增高而上调,P-ACC蛋白表达随药物浓度增高而上升;与空白对照组（0 mmol／L）中P-AMPK、P-ACC表达比较,10、15 mmol／L组中两者的差异均有统计学意义（P＜0.01）。ACC mRNA表达随二甲双胍浓度的增加呈下降趋势,5、10、15 mmol／L组表达量均较空白对照组显著下降（P＜0.01）。结论 初步实验研究发现,二甲双胍能够抑制人肝癌细胞HepG2的增殖,并从蛋白磷酸化水平和基因水平抑制ACC的活性,其抗肿瘤作用可能与激活AMPK和抑制ACC有关。     

Celecoxib inhibits MDR1 expression through COX-2-dependent mechanism in human hepatocellular carcinoma (HepG2) cell line

The role of COX-2 in the regulation of the expression of MDR1, a P-glycoprotein involved in hepatocellular carcinoma cell line, HepG2, was studied in the present investigation. Celecoxib, a selective inhibitor of COX-2, at 25 μM concentration increased the accumulation of doxorubicin in HepG2 cells and enhanced the sensitivity of the cells to doxorubicin by tenfold. The induction of MDR1 expression by PGE₂ and its downregulation by celecoxib or by COX-2 knockdown suggests that the enhanced sensitivity of HepG2 cells to doxorubicin by celecoxib is mediated by the downregulation of MDR1 expression, through COX-2-dependent mechanism. Further studies revealed the involvement of AP-1 in the celecoxib-induced downregulation of MDR1 expression. These experimental studies correlated well with in silico predictions and further suggested the inactivation of the signal transduction pathways involving ERK, JNK and p38. The present study thus demonstrates the usefulness of COX-2 intervention in overcoming the drug resistance in HepG2 cells.     

Proteome analysis of the effects of sorafenib on human hepatocellular carcinoma cell line HepG2

Sorafenib is a multi-target oral anticancer drug used as first-line treatment for patients with advanced human hepatocellular carcinoma (HCC). But the exact mechanism of sorafenib involved in HCC treatment is not clear yet. In this study, a comparative proteomic approach was performed to identify novel sorafenib-related proteins in HCC. Proteomes of HepG2 cells treated with sorafenib and the control (without sorafenib) were obtained by two-dimensional differential gel electrophoresis. Comprehensive analysis of proteins was focused on total protein spots to filtrate the different protein spots between the two groups. The differentially expressed proteins were identified by peptide mass fingerprinting with high-performance liquid chromatography-tandem mass spectrometry. Then, Western blot and immunohistochemistry were used to verify the expression of some candidate proteins. Results indicated that 19 protein spots were differentially expressed with significant changes, including 6 up-regulated proteins and 13 down-regulated proteins. It was confirmed by Western blot that expressions of Annexin A1 and cyclophilin A were down-regulated in sorafenib-treated HCC cell lines. Immunohistochemical study revealed their oncogenic role in HCC tissues. These observations might be novel findings leading to bring new insights into the exact mechanism of sorafenib and identify possible therapeutic targets.     

In vitro and in vivo studies of adenovirus-mediated human norepinephrine transporter gene transduction to hepatocellular carcinoma

The clinical value of (131)I-MIBG for targeted imaging and targeted radiotherapy is limited to neural crest-derived tumors expressing human norepinephrine transporters (hNET) protein. To extend (131)I-MIBG-targeted therapy to other nonexpressed hNET tumors, this study investigated the hNET expression in vitro and in vivo in HepG2 hepatoma mediated by recombinant adenovirus encoding the hNET gene (Ad-hNET). For this purpose, the HepG2 cells showed a 4.87-fold increase in (125)I-MIBG uptake after infection with Ad-hNET, and the uptake of (125)I-MIBG could be specifically inhibited by maprotiline. Immunohistological analysis, in vivo biological study and (131)I-MIBG scintigraphic imaging also revealed the high expression of hNET protein in hepatoma. This in vitro and in vivo studies demonstrate the feasibility of hNET gene transfer, meditated by adenovirus vector, could extend to tumors other than those derived from the neural crest, which provides a sound foundation for further investigation of hepatocellular carcinoma-targeted radiotherapy mediated by adenovirus transfection with hNET gene.     

舒尼替尼促进人肝癌细胞HepG2的凋亡及其分子机制

目的：探讨苹果酸舒尼替尼对人肝癌HepG2细胞凋亡的作用及其机制。方法：常规体外培养HepG2细胞,利用MTT法检测舒尼替尼杀伤HepG2细胞的IC50,Western blotting 检测药物处理前后HepG2细胞分子靶点蛋白表达,膜联蛋白(Annexin-V)/碘化丙啶(PI)双标法和TUNEL染色法检测舒尼替尼处理前后HepG2细胞凋亡情况,实时荧光定量PCR检测药物处理前后HepG2细胞凋亡基因 mRNA的表达情况。结果：舒尼替尼杀伤HepG2细胞的IC50值为（3.22±0.50）μmol/L。以对HepG2细胞无明显抑制作用的剂量1 μmol/L舒尼替尼处理HepG2细胞后,细胞内VEGFR1、VEGFR2、PDGFRα、Kit、FLT3蛋白表达均有不同水平下降（均P<0.05）,HepG2细胞的凋亡率\[(15.18±1.28)% vs (5.90±0.45)%,P<0.05\]、凋亡指数（AI）\[(23.54±4.73) vs (4.17±0.64), P<0.05\]均显著升高。舒尼替尼处理HepG2细胞后,上调促凋亡基因Bax、NOXA、PUMA、P53 mRNA表达水平（均P<0.05),降低抑凋亡基因Bcl-2、X-IAP mRNA表达水平（均P<0.05）。结论： 舒尼替尼能够诱导肝癌HepG2细胞凋亡,其机制可能是通过上调促凋亡基因的表达及降低抑凋亡基因表达水平来实现的。     

乙肝病毒x基因转染对奥曲肽抑制肝癌细胞HepG2生长的影响

背景与目的:体外及动物实验表明,生长抑素类似物奥曲肽可抑制肝癌生长,但奥曲肽治疗肝癌的临床疗效并不满意,原因不明。本研究拟探讨有乙型肝炎病毒感染的肝癌是否因其有x基因而改变了对奥曲肽作用的反应及其可能的机制。方法:采用3H鄄TdR掺入法了解细胞DNA合成,细胞免疫化学检测细胞的PCNA表达,AnnexinⅤ荧光标记法及TUNEL法观察细胞的凋亡,Westernblot法检测HepG2和HepG2x细胞ERK及生长抑素受体(somatostatinreceptors,SSTR)的表达。结果:1×10-5～1×10-9mol/L的奥曲肽显著地、浓度依赖性地抑制HepG2细胞3H鄄TdR掺入及PCNA表达(r=-0.917,P<0.01)。奥曲肽也促进HepG2细胞凋亡,其AnnexinⅤ的阳性率为(14.20±2.57)%,对照组仅为(1.18±0.13)%,两组间差异有显著性(P<0.05);TUNEL检测奥曲肽组凋亡指数为(18.8±3.3)%,对照组仅为(3.6±0.9)%,两组间差异有显著性(P<0.05)。奥曲肽及奥曲肽加拉米夫定对HepG2x细胞抑制生长和诱导凋亡作用不明显。HepG2x细胞的SSTR鄄2和SSTR鄄5表达均明显低于HepG2细胞(P<0.01);HepG2x细胞的细胞外信号调节激酶鄄1(extracellularsignal鄄regulatedkinase鄄1,ERK鄄1)和ERK鄄2表达均显著高于HepG2细胞(P<0.05)。奥曲肽未明显改变HepG2x细胞的ERKs表达。结论:转染x基因后的HepG2细胞SSTR鄄2及SSTR鄄5明显下调,导致奥曲肽对HepG2x细胞的生长抑制作用明显降低。     

缺氧对人肝癌HepG2细胞凋亡及p38MAPK通路的影响

目的:探讨缺氧对人肝癌HepG2细胞凋亡及p38MAPK通路的影响。方法:用三气培养箱培养肝癌细胞HepG2,建立缺氧细胞模型,CCK-8 法检测HepG2细胞的增殖率,流式细胞术检测细胞凋亡率,Real-time PCR分析p38MAPK mＲNA的表达,Western blot法检测p38MAPK及p-p38MAPK蛋白的表达变化。结果:缺氧可抑制人肝癌HepG2细胞的增殖,抑制细胞凋亡（P<0.05）;缺氧处理人肝癌HepG2细胞后,p38MAPK mＲNA的表达量下调(P<0.05);Western blot结果显示缺氧可下调p38MAPK、p-p38MAPK蛋白的表达（P<0.05）。结论:缺氧通过抑制p38MAPK通路抑制人肝癌HepG2细胞凋亡。     

Daurisoline suppresses esophageal squamous cell carcinoma growth in vitro and in vivo by targeting MEK1/2 kinase

Esophageal squamous cell carcinoma (ESCC) accounts for 90% of esophageal cancers and has a high mortality rate worldwide. The 5-year survival rate of ESCC patients in developing countries is <20%. Hence, there is an urgent need for developing new and effective treatments that are based on newly-discovered emerging molecules and pathways to prevent ESCC occurrence and recurrence. We investigated the effects of Daurisoline, a bis-benzylisoquinoline alkaloid extracted from the rhizome of menisperum dauricum, on ESCC cell proliferation and elucidated the molecular mechanisms underlying its functions. To explore the effects of Daurisoline on ESCC growth in vitro and in vivo, cell proliferation assays and anchorage-independent growth assays were performed and a patient-derived xenograft (PDX) model was established. Subsequently, phosphoproteomics, molecular docking analysis, pull down assays, mutation experiments and in vitro kinase assay were performed to explore the mechanism of Daurisoline's function on ESCC. Daurisoline inhibited ESCC proliferation in vitro and reduced ESCC PDX exnograft growth in vivo by reducing ERK1/2 phosphorylation. Furthermore, it directly bound to MEK1 (at Asn78 and Lys97) and MEK2 (at Asp194 and Asp212) kinases to inactivate the ERK1/2 signaling pathway. Our results suggest that Daurisoline is a dual inhibitor of MEK1 and MEK2 and suppresses ESCC growth both in vitro and in vivo by inactivating the ERK1/2 signaling pathway. This is first report on the use of MEK inhibitor for ESCC and highlights its potential applications for ESCC treatment and prevention.     

Enhancement of cytotoxic and pro-apoptotic effects of 2-aminophenoxazine-3-one on the rat hepatocellular carcinoma cell line dRLh-84, the human hepatocellular carcinoma cell line HepG2, and the rat normal hepatocellular cell line RLN-10 in combination with 2-deoxy-D-glucose

The cytotoxic and pro-apoptotic effects of a single dose of 2-aminophenoxazine-3-one (Phx-3) or 2-deoxyglucose (2-DG) or of a combined dose of Phx-3 and 2-DG were studied in the rat hepatocellular carcinoma cell line dRLh-84, the human hepatocellular carcinoma cell line HepG2 and the rat normal hepatocellular cell line RLN-10. The number of viable cells decreased in a dose-dependent manner, when dRLh-84, HepG2 or RLN-10 cells were treated with 2-DG (0.5-20?mM) or Phx-3 (1-50?μM) alone at 37?C for 48?h. When these cells were treated with 10?mM 2-DG and different concentrations of Phx-3, the number of viable cells decreased dose-dependently and in an additive manner for these agents. A single dose of 2 or 10?μM Phx-3 induced apoptotic morphology characterized by nuclear condensation and cell shrinkage in dRLh-84, HepG2 and RLN-10 cells, while a single dose of 10?mM 2-DG did not. When Phx-3 (2 or 10?μM) treatment was combined with 2-DG (10?mM) treatment in these three cell lines, the cells with apoptotic morphology increased extensively, which was confirmed by flow cytometric analysis. In addition, autophagic morphology characterized by cytosolic vacuole formation was significantly increased in the hepatocellular carcinoma cell lines dRLh-84 and HepG2 but not in the normal hepatocellular cell line RLN-10 after a single dose of Phx-3 or 2-DG or a combined dose of Phx-3 and 2-DG. Furthermore, when dRLh-84 and HepG2 cells were treated with Phx-3 alone or a combined dose of Phx-3 and 2-DG, depolarization of the mitochondria was extensive, but that of the normal cell line RLN-10 was not. These results may imply that the mechanism for the apoptosis of hepatocellular carcinoma cells caused by Phx-3 alone or a combined dose of Phx-3 and 2-DG differs from that of the normal cell line RLN-10. The present results demonstrate that Phx-3 alone may be beneficial for targeting liver cancer and that its anticancer activity may be enhanced by 2-DG. However, a combined dose of Phx-3 and 2-DG may exert adverse effects on normal liver cells, as evidenced by the cytotoxic and pro-apoptotic effects of the combined treatment in the rat normal hepatocellular cell line RLN-10.     

PKCa对肝癌药物敏感性的作用

目的:探讨 PKCa对肝癌药物敏感性的作用及在肝癌耐药中的意义.方法:利用siRNA技术,抑制HepG2细胞PKCa表达;用PMA(PKC激动剂)刺激HepG2细胞PKCa高表达,用MTT方法比较PKCa表达量的变化对HepG2细胞药物敏感性的影响.结果:经Western blotting analysis验证,siRNA对PKCa表达有显著的抑制作用;PMA刺激后PKCa呈高表达.MTT显示转染siRNA组IC50值为6.445±0.8549;用PMA处理组IC50值为11.540±1.3647.两者与对照组有显著差异性(P<0.05).结论: 肝癌细胞中,PKCa 表达量的变化影响肝癌细胞对抗癌药物(表阿霉素)的敏感性.抑制PKCa表达可以增加肝癌细胞的药物敏感性.实验结果为提高肝癌综合治疗的效果提供了研究基础.     

Recombinant leukemia inhibitory factor suppresses human medullary thyroid carcinoma cell line xenografts in mice

Medullary thyroid carcinoma (MTC) is a neoplasm of the endocrine system, which originates from parafollicular C-cells of the thyroid gland. For MTC therapy, the Food and Drug Administration recently approved vandetanib and cabozantinib, multi-kinase inhibitors targeting RET and other tyrosine kinase receptors of vascular endothelial growth factor, epidermal growth factor, or hepatocyte growth factor. Nevertheless, not all patients with the progressive MTC respond to these drugs, requiring the development of additional therapeutic modalities that have distinct activity. Previously, we reported that expression of activated Ras or Raf in the human MTC cell lines, TT and MZ-CRC-1, can induce growth arrest and RET downregulation via a leukemia inhibitory factor (LIF)-mediated autocrine/paracrine loop. In this study, we aimed to evaluate bacterially-produced recombinant human LIF for its efficacy to suppress human MTC xenografts in mice. Here, we report that, consistent with its effects in vitro, locally or systemically administered recombinant LIF effectively suppressed growth of TT and MZ-CRC-1 xenografts in mice. Further, as predicted from its effects in TT and MZ-CRC-1 cell cultures in vitro, recombinant LIF activated the JAK/STAT pathway and downregulated RET and E2F1 expression in tumors in mice. These results suggest that LIF is a potent cytostatic agent for MTC cells, which regulates unique mechanisms that are not targeted by currently available therapeutic agents.