韓曉東 周優(yōu)優(yōu) 鄭斯文 李貞 宋智琦
姜黃素對(duì)人黑素瘤細(xì)胞株A375和C8161細(xì)胞AKT/mTOR信號(hào)通路的影響
韓曉東 周優(yōu)優(yōu) 鄭斯文 李貞 宋智琦
目的 探討姜黃素對(duì)惡性黑素瘤體外抗癌作用的分子機(jī)制。方法 體外培養(yǎng)的人黑素瘤細(xì)胞株A375和C8161分為實(shí)驗(yàn)組和對(duì)照組。實(shí)驗(yàn)組經(jīng)不同濃度姜黃素處理一定時(shí)間,對(duì)照組采用二甲基亞砜處理。采用噻唑藍(lán)法檢測(cè)姜黃素對(duì)A375和C8161細(xì)胞增殖的影響,體外侵襲實(shí)驗(yàn)檢測(cè)姜黃素對(duì)A375和C8161細(xì)胞侵襲的影響,流式細(xì)胞儀檢測(cè)姜黃素對(duì)A375和C8161細(xì)胞周期的影響,Western印跡檢測(cè)姜黃素對(duì)A375和C8161細(xì)胞AKT/mTOR信號(hào)通路相關(guān)蛋白表達(dá)的影響。結(jié)果 噻唑藍(lán)法顯示,姜黃素分別在5~15 mg/L和5~10 mg/L濃度時(shí),對(duì)A375和C8161細(xì)胞抑制作用呈量效關(guān)系;在0~48 h呈時(shí)效關(guān)系,與對(duì)照組相比差異有統(tǒng)計(jì)學(xué)意義(P<0.001)。其24 h的IC50分別為10 mg/L和5 mg/L。體外侵襲試驗(yàn)顯示,10 mg/L和5 mg/L姜黃素分別作用于A375和C8161細(xì)胞72 h,可明顯抑制細(xì)胞侵襲(P<0.001)。流式細(xì)胞儀檢測(cè)顯示,10 mg/L和5 mg/L姜黃素分別作用于A375和C8161細(xì)胞24 h,細(xì)胞周期阻滯于G2/M期;A375細(xì)胞G2/M期比例為35.00%±3.54%,與對(duì)照組120.80%±7.46%相比,差異有統(tǒng)計(jì)學(xué)意義(P<0.001);C8161細(xì)胞G2/M期比例為19.33%±4.04%,與對(duì)照組85.00%±9.53%相比,差異有統(tǒng)計(jì)學(xué)意義(P<0.001)。Western印跡檢測(cè)顯示,分別經(jīng)10 mg/L和5 mg/L姜黃素作用于后,A375和C8161細(xì)胞AKT/mTOR信號(hào)通路相關(guān)蛋白表達(dá)水平下降。結(jié)論 姜黃素抑制人黑素瘤細(xì)胞株A375和C8161增殖及侵襲機(jī)制可能與其誘導(dǎo)細(xì)胞周期阻滯及抑制AKT/mTOR信號(hào)通路活化有關(guān)。
黑色素瘤,實(shí)驗(yàn)性;姜黃素;細(xì)胞增殖;細(xì)胞周期;信號(hào)傳導(dǎo)
惡性黑素瘤(簡(jiǎn)稱惡黑)是一種皮膚惡性腫瘤,以黑素細(xì)胞異常增殖并突破基底膜為特征。大部分轉(zhuǎn)移性惡黑對(duì)多種化療藥物抵抗[1-2],患者長(zhǎng)期生存率較低[3-4],因此,治療惡黑是亟待攻克的難題。姜黃素是從草本植物姜黃的根莖中提取出來的一種酚類色素,是姜黃的主要有效成分,具有抗炎、抗氧化及抗腫瘤等作用[5]。研究發(fā)現(xiàn),姜黃素能夠抑制惡黑A375 細(xì)胞增殖并誘導(dǎo)細(xì)胞凋亡[6]。我們前期[7]研究發(fā)現(xiàn),谷氨酸受體拮抗劑MK-801及CPCCOEt可誘導(dǎo)人惡黑WM451細(xì)胞樹突發(fā)育,使細(xì)胞骨架蛋白重組,導(dǎo)致其樹突變細(xì)長(zhǎng),呈樹枝狀,接近正常黑素細(xì)胞,并可抑制WM451細(xì)胞的增殖、侵襲及遷移[7-8]。本研究旨在探討姜黃素對(duì)惡黑細(xì)胞增殖、侵襲、周期的作用及其相關(guān)機(jī)制。
細(xì)胞系:人惡黑A375和C8161細(xì)胞株購(gòu)自中國(guó)醫(yī)學(xué)科學(xué)院基礎(chǔ)醫(yī)學(xué)研究所北京協(xié)和醫(yī)學(xué)院細(xì)胞資源中心。姜黃素(編號(hào)A0086,CAS登錄號(hào)458-37-7,純度≥98%)購(gòu)自成都曼斯特生物科技有限公司。二甲基亞砜(DMSO,美國(guó)Sigma公司)溶解至濃度為100 g/L于4℃儲(chǔ)存?zhèn)溆?。高糖DMEM培養(yǎng)基(美國(guó)Gibco公司),胎牛血清(FBS,浙江天杭生物科技有限公司),不含乙二胺四乙酸(EDTA)的胰蛋白酶(美國(guó) Hyclone公司),噻唑藍(lán)(MTT)、TritonX-100(美國(guó)Sigma公司),基質(zhì)膠Matrigel(美國(guó)BD公司),熒光染料PI(碘化丙錠)、核糖核酸酶RNase(日本 TaKaRa公司)???AKT、p-AKT(Ser473)、p-mTOR (Ser2448)、p-P70S6K(Thr389)兔抗(美國(guó)Cell Signaling Technology公司);抗β肌動(dòng)蛋白鼠抗(美國(guó)Sigma公司)。
1.細(xì)胞培養(yǎng)[9]:A375 與 C8161 細(xì)胞均用含 10%胎牛血清的DMEM,常規(guī)37℃、5%CO2培養(yǎng)箱中培養(yǎng),取對(duì)數(shù)生長(zhǎng)期細(xì)胞進(jìn)行實(shí)驗(yàn)。姜黃素20mg標(biāo)準(zhǔn)品+200μl二甲基亞砜(DMSO),配置成100mg/L原液。
2.MTT法檢測(cè)姜黃素對(duì)細(xì)胞增殖的影響:方法參照文獻(xiàn)[9],分實(shí)驗(yàn)組和對(duì)照組,每組設(shè)3個(gè)復(fù)孔。實(shí)驗(yàn)組加入姜黃素原液(100 g/L),終濃度分別為5、10、15、20、25、30、35 mg/L,對(duì)照組加等量 DMSO,分別于24、48、72、96 h加入 MTT并于培養(yǎng)箱孵育 4 h,然后加入200 μl DMSO,充分振蕩后用酶標(biāo)儀檢測(cè)490 nm波長(zhǎng)下的各孔吸光度值(A)。細(xì)胞增殖抑制率(%)=(1-實(shí)驗(yàn)組A值/對(duì)照組A值)×100%。
3.體外Matrigel侵襲實(shí)驗(yàn):參照文獻(xiàn)[9]。用24孔Transwell小室按說明書方法,每組3個(gè)復(fù)孔。實(shí)驗(yàn)組A375和C8161細(xì)胞分別加入含10 mg/L和5 mg/L姜黃素的培養(yǎng)液,姜黃素原液加入量分別為0.01 μl和 0.005 μl,對(duì)照組加等量 DMSO,下室按 500 μl/孔加入趨化液(DMEM+10%FBS)。置培養(yǎng)箱中孵育72 h。倒置顯微鏡下觀察穿膜細(xì)胞數(shù),光鏡(×200)下隨機(jī)選取5個(gè)視野(上、下、左、右、中間)照相、計(jì)數(shù)。
4.流式細(xì)胞儀檢測(cè)細(xì)胞周期:將A375與C8161細(xì)胞以合適密度接種于6 cm培養(yǎng)皿,經(jīng)10、5 mg/L姜黃素(含姜黃素原液量分別為0.4 μl和0.2 μl)作用24 h,對(duì)照組加等量DMSO。用不含EDTA的胰酶消化收集處理后的A375細(xì)胞,PBS洗滌,用75%預(yù)冷乙醇固定細(xì)胞4 h,分別用500 μl配好的染色液含480 μl PBS、5μl PI(5 g/L)、5 μl RNase(10g/L)、10μlTritonX100(10%)重懸,置 37℃30min后流式細(xì)胞儀檢測(cè)分析周期變化。
5.Western印跡分析:分別用10、5 mg/L姜黃素(含姜黃素原液量分別為 0.4 μl和 0.2 μl) 處理A375與C8161細(xì)胞,對(duì)照組加等量DMSO,24 h后收集細(xì)胞。加入蛋白裂解液于冰上裂解30 min,離心后收集上清液提取細(xì)胞總蛋白,考馬斯亮藍(lán)法測(cè)定蛋白濃度。方法參照文獻(xiàn)[9]。
姜黃素能夠抑制A375和C8161細(xì)胞增殖(表1,2)。姜黃素分別在5~15 mg/L和5~10 mg/L濃度范圍內(nèi)對(duì)A375和C8161細(xì)胞活性抑制作用成量效關(guān)系,在0~48 h內(nèi)呈時(shí)效關(guān)系,24 h的IC50分別為10 mg/L和5 mg/L,與對(duì)照組相比差異有統(tǒng)計(jì)學(xué)意義(P<0.001)。
如表3所示,經(jīng)終濃度為10 mg/L(IC50)姜黃素培養(yǎng)液處理A375細(xì)胞72 h,實(shí)驗(yàn)組細(xì)胞侵襲數(shù)量(35.00±3.54)低于對(duì)照組(120.80±7.46),差異有統(tǒng)計(jì)學(xué)意義(t=23.23,P< 0.001);5 mg/L(IC50)姜黃素培養(yǎng)液處理C8161細(xì)胞72 h,實(shí)驗(yàn)組細(xì)胞侵襲數(shù)量(19.33±4.04)低于對(duì)照組(85.00±9.53),差異有統(tǒng)計(jì)學(xué)意義(t=10.98,P<0.001),說明一定濃度的姜黃素能抑制A375細(xì)胞(圖1)和C8161細(xì)胞(圖2)侵襲。用姜黃素濃度≥15 mg/L處理A375細(xì)胞,濃度≥10 mg/L處理C8161細(xì)胞,72 h后觀察兩組細(xì)胞侵襲情況,均未發(fā)現(xiàn)侵襲細(xì)胞。
表1 不同濃度姜黃素在不同時(shí)間對(duì)A375細(xì)胞增殖抑制率(%,±s)
表1 不同濃度姜黃素在不同時(shí)間對(duì)A375細(xì)胞增殖抑制率(%,±s)
注:n=3。二甲基亞砜對(duì)照組的抑制率設(shè)為“0”;各濃度組與對(duì)照組比較,均P<0.001
姜黃素(mg/L) 24 h 48 h 72 h 96 h 5 41.39±5.23 61.98±0.75 73.15±0.22 80.79±1.33 10 48.67±2.06 73.87±2.48 83.38±0.31 86.81±0.87 15 53.08±3.44 80.00±1.43 89.67±0.41 91.34±0.61 20 57.83±2.57 83.03±1.28 91.57±0.30 92.85±0.27 25 60.00±2.01 84.00±1.06 91.67±0.25 93.27±0.24 30 61.31±1.16 85.14±0.49 92.60±0.15 93.76±0.19 35 69.32±5.20 88.18±0.65 94.22±0.40 94.97±0.35
表2 不同濃度姜黃素在不同時(shí)間對(duì)C8161細(xì)胞增殖抑制率(%,±s)
表2 不同濃度姜黃素在不同時(shí)間對(duì)C8161細(xì)胞增殖抑制率(%,±s)
注:n=3。二甲基亞砜對(duì)照組的抑制率設(shè)為“0”;各濃度組與對(duì)照組比較,均P<0.001
姜黃素(mg/L) 24 h 48 h 72 h 96 h 5 51.35±2.80 79.20±1.42 83.75±2.05 92.43±1.34 10 59.08±2.18 80.76±1.23 89.18±1.57 94.41±0.22 15 62.79±2.13 82.07±1.27 90.82±0.67 94.81±0.35 20 65.53±1.45 88.02±0.78 93.24±0.47 96.03±0.27 25 69.04±0.95 89.00±0.16 93.52±0.40 96.46±0.14 30 71.75±0.93 89.70±0.54 94.18±0.18 96.51±0.56 35 73.71±0.52 90.10±3.19 94.34±0.17 96.99±0.13
表3所示,10 mg/L(IC50)姜黃素處理24 h后誘導(dǎo)A375細(xì)胞G2/M期阻滯比例為(48.07±7.09)%,與對(duì)照組(21.30±0.75)%相比差異有統(tǒng)計(jì)學(xué)意義(t=6.50,P< 0.01);5 mg/L(IC50)姜黃素處理 24 h后誘導(dǎo)C8161細(xì)胞G2/M期阻滯比例為(33.80±1.25)%,與對(duì)照組(25.23±2.31)%相比差異有統(tǒng)計(jì)學(xué)意義(t=5.65,P<0.01);姜黃素組兩個(gè)細(xì)胞株各自對(duì)應(yīng)的G0/G1細(xì)胞比例小于DMSO對(duì)照組,說明一定濃度姜黃素處理24 h后,可引起A375細(xì)胞(圖3)和C8161細(xì)胞(圖4)G2/M期的阻滯。
圖1 10 mg/L(IC50)姜黃素抑制A375細(xì)胞侵襲(結(jié)晶紫染色×200)
圖2 5 mg/L(IC50)姜黃素抑制C8161細(xì)胞侵襲(結(jié)晶紫染色×200)
圖3 10 mg/L(IC50)姜黃素誘導(dǎo)A375細(xì)胞G2/M期阻滯
圖4 5 mg/L(IC50)姜黃素誘導(dǎo)C8161細(xì)胞G2/M期阻滯
采用A375和C8161細(xì)胞的IC50(分別為10mg/L和5 mg/L)的姜黃素處理24 h,Western印跡檢測(cè)結(jié)果示 A375和 C8161細(xì)胞 p-AKT、p-mTOR、pp70S6K蛋白表達(dá)水平均下降,總AKT表達(dá)不變(圖5),β肌動(dòng)蛋白為內(nèi)參照。
表3 姜黃素對(duì)A375和C8161細(xì)胞侵襲的抑制及對(duì)周期的阻滯作用
圖5 Western印跡檢測(cè)姜黃素對(duì)A375和C8161細(xì)胞AKT/mTOR信號(hào)通路相關(guān)蛋白表達(dá)的影響 1:二甲基亞砜;2:10 mg/L(IC50)姜黃素;3:5 mg/L(IC50)姜黃素。β 肌動(dòng)蛋白為內(nèi)參照
惡黑對(duì)常規(guī)化療不敏感,易產(chǎn)生耐藥且藥物毒副作用大,導(dǎo)致其療效不佳。越來越多天然或植物來源且毒副作用小的藥物,如,姜黃素,被用作化療輔助藥物[10]。細(xì)胞運(yùn)動(dòng)能力與PI3K/AKT信號(hào)通路活化有關(guān)。異?;罨腜I3K/AKT信號(hào)通路能激活其下游分子mTOR[11],mTOR隨后活化其下游分子p70S6K,p70S6K的活化能促進(jìn)肌動(dòng)蛋白細(xì)絲重構(gòu),進(jìn)而促進(jìn)細(xì)胞運(yùn)動(dòng)[12]。我們通過Transwell侵襲實(shí)驗(yàn)研究顯示,姜黃素可顯著抑制惡黑細(xì)胞侵襲。此外,我們用Western印跡檢測(cè)發(fā)現(xiàn)姜黃素能顯著下調(diào)AKT、mTOR、p70S6K蛋白的磷酸化水平,而對(duì)AKT總蛋白水平無影響。由此,我們推測(cè)姜黃素可能是通過抑制PI3K/AKT信號(hào)通路活化從而抑制細(xì)胞肌動(dòng)蛋白細(xì)絲重構(gòu)并進(jìn)而抑制惡黑細(xì)胞侵襲。
細(xì)胞的增殖、凋亡均是細(xì)胞周期依賴性的,細(xì)胞周期的失控是腫瘤發(fā)病中極其重要的環(huán)節(jié)。細(xì)胞周期素(cyclin)及周期素依賴性激酶(cyclindependent kinases,CDK)是細(xì)胞周期的重要調(diào)節(jié)因子。有研究顯示,姜黃素可通過上調(diào)p53、p21、p27和 CHK2),誘導(dǎo)惡黑細(xì)胞凋亡和 G2/M 期阻滯[13]。另有研究發(fā)現(xiàn),姜黃素類似物D6能夠下調(diào)細(xì)胞周期蛋白 cyclin B1、cyclin F、cdc25B 和 CDK4 的表達(dá),導(dǎo)致惡黑細(xì)胞G2/M期阻滯,進(jìn)而抑制惡黑細(xì)胞增殖[14]。本研究通過流式細(xì)胞儀檢測(cè)發(fā)現(xiàn),姜黃素能夠誘導(dǎo)惡黑A375及C8161細(xì)胞周期明顯阻滯于G2/M期,遺憾的是未對(duì)其機(jī)制進(jìn)行深入探討。
PI3K/AKT/mTOR信號(hào)通路在包括惡黑在內(nèi)的多種腫瘤中呈活化狀態(tài),且與腫瘤發(fā)生有關(guān)。有研究發(fā)現(xiàn),姜黃素類似物D6可抑制黑素瘤細(xì)胞增殖和誘導(dǎo)細(xì)胞凋亡,其機(jī)制是抑制PI3K/AKT信號(hào)通路的活化[14]。為了闡明姜黃素是否可通過影響PI3K/AKT/mTOR信號(hào)通路來影響惡黑,我們采用Western印跡檢測(cè)發(fā)現(xiàn),姜黃素能顯著下調(diào)AKT、mTOR、P70S6K蛋白的磷酸化水平,而對(duì)AKT總蛋白無影響。我們推測(cè),對(duì)PI3K/AKT/mTOR信號(hào)通路活化的抑制可能是姜黃素抑制惡黑進(jìn)展的機(jī)制之一。
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2014-07-02)
(本文編輯:吳曉初)
Effects of curcumin on the AKT/mTOR signaling pathway in human melanoma cell lines A375 and C8161
Han Xiaodong,Zhou Youyou,Zheng Siwen,Li Zhen,Song Zhiqi.Department of Dermatology,First Affiliated Hospital of Dalian Medical University,Dalian 116011,China
Song Zhiqi,Email:szqdalian@163.com
ObjectiveTo explore molecular mechanisms underlying thein vitrocounteracting effect of curcumin on malignant melanoma.MethodsCultured A375 and C8161 human melanoma cells were cultivatedin vitro,and randomly divided into several test groups and a control group to be treated with different concentrations of curcumin and dimethylsulfoxiderespectivelyfordifferentdurations.Then,methylthiazolyltetrazolium(MTT)assay,Transwellassay,flow cytometryandWesternblotwere performedto evaluate the effectofcurcuminonthe proliferation,invasionandcellcycle of,as well as expressions of AKT/mTOR signaling pathway-related proteins in A375 and C8161 cells respectively.Statistical analysiswascarriedoutbyusingttest.ResultsMTTassayshowedthatthetreatmentwithcurcuminof5-35mg/Lfor24-96 hours significantly inhibited the proliferation of both A375 and C8161 cells compared with that with dimethyl sulfoxide(allP<0.001),andthe inhibitoryeffectwasina dose-dependentmannerwithinthe range of5-15mg/LforA375cellsand within the range of 5-10 mg/L for C8161 cells,and in a time-dependent manner from 0 to 48 hours for both cells.After treatmentfor24hours,the50%inhibitoryconcentration(IC50)ofcurcuminagainstA375cellsandC8161cellswas10mg/L and 5 mg/L respectively.Transwell assay demonstrated that the invasion of A375 and C8161 cells was significantly suppressed by 72-hour treatment with curcumin at 10 mg/L and 5 mg/L respectively (bothP<0.001).Flow cytometry showed that the cell cycle of A375 and C8161 cells was arrested at G2/M phase after 24-hour treatment with curcumin at 10 mg/Land5mg/Lrespectively,withsignificantdifferences in the proportion of A375 cells and C8161 cells in G2/M phase between the test group and control group (A375 cells:35.00% ±3.54%vs.120.80% ±7.46%,P<0.001;C8161 cells:19.33% ±4.04%vs.85.00% ±9.53%,P<0.001).Western blot revealed that the expressions of AKT/mTOR signaling pathway-related proteins were decreased in A375 and C8161 cells after 24-hour treatment with 10 mg/L and 5 mg/L curcumin respectively.ConclusionCurcumin can inhibit the proliferation and invasion of A375 and C8161 cells,likely byblockingcellcycleandinhibitingactivationoftheAKT/mTORsignalingpathway.
Melanoma,experimental;Curcumin;Cell proliferation;Cell cycle;Signal transduction
10.3760/cma.j.issn.0412-4030.2015.06.004
國(guó)家自然科學(xué)基金(81472865、81171491);遼寧省自然科學(xué)基金(201102056、2014023005)
116011大連醫(yī)科大學(xué)附屬第一醫(yī)院皮膚科
宋智琦,Email:szqdalian@163.com