MDA-7/IL-24-HT7融合蛋白的制备及其对肿瘤细胞凋亡的诱导作用

目的：构建MDA-7/IL-24-HT7原核及真核表达质粒,制备MDA-7/IL-24-HT7融合蛋白,研究该融合蛋白在肿瘤细胞内的定位及其对肿瘤细胞致凋亡作用。方法：PCR扩增MDA-7/IL-24基因,插入含有HaloTag (HT7)标签的载体中,构建MDA-7/IL-24-HT7原核及真核表达质粒;MDA-7/IL-24-HT7融合蛋白经IPTG诱导表达后纯化。利用带有荧光标记的HT7配基观察MDA-7/IL-24-HT7在肿瘤细胞内的定位。MTT法及AnnexinV-PI染色法检测MDA-7/IL-24-HT7对肿瘤细胞生长和凋亡的影响。结果：成功构建了表达MDA-7/IL-24-HT7融合蛋白的原核及真核表达质粒,MDA-7/IL-24-HT7融合蛋白主要存在于E.coli BL21的包涵体内。MDA-7/IL-24-HT7融合蛋白定位于肿瘤细胞的内质网上。MDA-7/IL-24-HT7融合蛋白可抑制肿瘤细胞的生长,1 mg/ml MDA-7/IL-24-HT7 融合蛋白作用大肠癌HCT116细胞、肝癌SMMC7721细胞96 h后,细胞凋亡率分别为（34.7±1.3）% 和（22.1±0.9）%,显著高于未处理的肿瘤细胞（P<0.01）。结论：带有HaloTag标签的MDA-7/IL-24-HT7融合蛋白可抑制肿瘤细胞增殖和诱导肿瘤细胞凋亡。     

Mda-7/IL-24基因转染对肝癌细胞生长的影响

目的研究Mda-7/IL-24基因对肝癌细胞系Hep3B生长的影响。方法构建Mda-7/IL-24基因的真核表达载体pcDNA3.1/Mda-7/IL-24,用脂质体介导的基因转染法分别将真核重组体pcD-NA3.1/Mda-7/IL-24和pcDNA3.1空载体质粒导入人肝癌细胞系Hep3B细胞中,经G418筛选获得细胞克隆。通过聚合酶链式反应（PCR）、免疫组织化学等方法检测基因和蛋白的表达、细胞生长增殖情况。结果将pcDNA3.1载体和pcDNA3.1/Mda-7/IL-24重组体转染肝癌细胞系Hep3B中,RT-PCR结果显示pcDNA3.1/Mda-7/IL-24克隆中有680bp的扩增条带,而pcDNA3.1空载体转染的克隆未见的扩增条带,未转染的Hep3B细胞亦未见680bp的条带;转染Mda-7/IL-24的Hep3B细胞与空白质粒载体转染的Hep3B细胞和Hep3B细胞的生长速度相比,后两者生长速度较快。结论将外源性Mda-7/IL-24基因导入Hep3B细胞后,可以抑制细胞生长。     

抑瘤基因mda-7/IL-24 研究进展

 黑色素瘤分化相关基因-7(Melanoma differentiation-associated gene-7,mda-7)是一种肿瘤抑制基因,其定位于染色体的1q32位点,位于一群分泌IL-10,IL-19和IL-20细胞因子的基因群中,基于氨基酸的同源性预测蛋白质的结构、染色体的定位以及细胞因子样特性,mda-7被命名为IL-24 [ 1 ].mda-7 cDNA 编码一个206个氨基酸的蛋白质,分子质量约为23.8 kDa.通过Prosite 数据库分析发现mda-7/IL-24在第85,99和126位点存在N-糖基化,6个磷酸化位点(即位于101, 111和161位点的酪蛋白激酶Ⅱ; 88, 133 和 161位点的蛋白激酶C) 以及开始于101 位点的IL-10信号图形,     

MDA 7/IL-24抗肿瘤作用研究进展MDA 7/IL-24抗肿瘤作用研究进展

黑色素瘤分化相关基因(melonoma differentiation associated gene 7,MDA 7)是通过消减杂交法从人黑色素瘤细胞中分离出来的,因其分子生物学特性与IL-10相似,故将其归入IL-10家族,并命名为IL-24。MDA 7/IL-24具有广泛的抗肿瘤生物学作用,它能够通过多种途径对肿瘤细胞产生生长抑制作用,其作用机理与凋亡诱导、细胞自噬、抑制肿瘤新生血管形成和侵袭转移、免疫调节作用等有关。作为一种具有多种途径抗肿瘤作用的细胞因子,MDA 7/IL-24在临床Ⅰ期试验中已显示出良好的治疗效果,被誉为治疗癌症的“魔法子弹”。本文就MDA 7/IL-24在肿瘤治疗中的作用及其机制研究作一综述,以期为MDA 7/IL-24在肿瘤基因治疗中研究提供参考和借鉴。     

人mda-7/IL-24对慢性粒细胞白血病K562细胞的抑制作用

摘 要 目的: 探索人黑素瘤分化相关基因-7（melanoma differentiation associated gene7，mda7；又称IL-24）对慢性粒细胞白血病K562细胞的抑制作用。方法：用RTPCR法检测11个造血系统恶性肿瘤细胞系mda-7受体的转录情况。用脂质体转染法将构建的重组真核表达载体pTargetIL24转染K562细胞。以RTPCR和Western blotting方法检测转染的K562细胞mda7的表达情况；通过MTT法、集落形成实验、流式细胞术、AnnexinⅤ/PI检测mda7/IL24对K562细胞增殖、集落形成、细胞周期和凋亡的影响；以裸鼠移植瘤模型观察mda-7对K562细胞移植瘤的治疗作用。结果：在11个造血系统恶性肿瘤细胞系（NB4、HL60、CEM、Namalwa、Jurkat、KG1a、U937、K562、Ramos、J61、HEL细胞）中没有检测到完整mda7受体的表达。转染mda7的K562细胞能显著表达mda-7mRNA及其蛋白；其与转染空载体和未转染的K562细胞相比，细胞增殖活力以及集落形成能力明显下降（P＜0.05），细胞周期阻滞于G0/G1期（P＜0.05），但细胞凋亡率没有明显变化。裸鼠体内实验证实了mda7/IL24明显抑制K562细胞移植瘤生长（P＜0.01）。结论：mda-7/IL-24对白血病细胞系K562具有明显的体内外抑制作用，该作用与mda7/IL24引起细胞周期G0/G1期阻滞有关。     

癌特异性的细胞凋亡诱导因子MDA-7／IL-24的研究进展

黑色素瘤分化相关基因7（melanoma differ-entiation-associatedgene-7，MDA-7）最初是由Jiang等^[2]利用消减杂交法从β干扰素（IFN-β）和瑞香素（MEZ）诱导的终末分化人类黑色素瘤细胞中克隆到的基因。后来根据其结构序列的同源性，染色体的定位及类细胞因子的特点，被国际人类基因组织（HUGO）重新命名为IL-24。MDA-7／IL-4位于人类染色体的lq32-33，     

腺病毒介导IL-24联合化疗药物增强对肝癌细胞PLC/PRF/5增殖的抑制

目的：研究腺病毒介导IL-24基因（Ad.IL-24）与化疗药物联用对肝癌细胞株PLC/PRF/5增殖的抑制作用。方法：用Ad.IL-24分别联合化疗药物氟尿嘧啶（fluorouracil,5-Fu）和表柔比星（epirubicin,EPI）处理培养的肝癌细胞株PLC/PRF/5,MTT法检测细胞增殖抑制率,流式细胞术（FCM）检测细胞周期和凋亡率。结果：10 MOI Ad.IL-24与25μg/ml5-Fu联合应用后72h,PLC/PRF/5细胞增殖抑制率达（67.4±0.58）%,显著高于单用Ad.IL-24组的（46.8±0.74）%和5-Fu组的（29.3±0.60）%（均P〈0.05）;10MOIAd.IL-24与2.5μg/mlEPI联合应用后72h,PLC/PRF/5细胞增殖抑制率达（72.5±0.92）%,显著高于单用Ad.IL-24组的（46.8±0.74）%和EPI组的（32.2±0.69）%（均P〈0.05）。流式细胞术检测结果显示,Ad.IL-24与5-Fu或EPI联合应用明显导致细胞在G2/M期阻滞;Ad.IL-24＋5-Fu组细胞凋亡率为（52.15±2.32）%,显著高于单用Ad.IL-24组的（28.36±3.49）%和5-Fu组的（8.27±2.61）%（均P〈0.05）;Ad.IL-24＋EPI组细胞凋亡率为（58.67±1.73）%,显著高于单用Ad.IL-24组的（28.36±3.49）%和EPI组的（11.82±1.91）%（均P〈0.05）。结论：Ad.IL-24与5-Fu或EPI联用能显著提高对肝癌细胞株PLC/PRF/5增殖的抑制作用。     

MDA-7/IL-24对Burkitt淋巴瘤细胞的诱导分化作用

目的:研究黑色素瘤分化相关基因-7(melanoma differentiation associated gene 7,MDA-7)/IL-2对Burkitt淋巴瘤细胞的促分化作用并探讨其作用机制.方法:构建稳定过表达MDA-7/IL-24的人Burkitt淋巴瘤Raji和Daudi细胞株,MTS法检测稳定转染MDA-7/IL-24对Raji和Daudi细胞活力的影响;Transwell小室实验检测转染MDA-7/IL-24对Raji和Daudi细胞侵袭和迁移能力的影响;流式细胞术检测细胞凋亡水平及免疫表型;Western blotting技术检测转染MDA-7/IL-24对Raji和Daudi细胞表达分化相关蛋白Myb、BLIMP1及BCL-6的影响;建立裸鼠Raji细胞移植瘤模型,检测在体内环境中稳定转染MDA-7/IL-24对Raji细胞生物活性的影响.结果:过表达MDA-7/IL-24的Raji和Daudi细胞其增殖(P.＜0.05)、侵袭(P＜0.01)及迁移(P＜0.01)能力均明显下降,但凋亡细胞无明显增加(P＞0.05),表达CD45及CD138的水平均明显增加(P＜0.01),而表达CD10的水平明显下降(P＜0.01).过表达MDA-7/IL-24的Raji和Daudi细胞表达BLIMP1的水平明显增加(P＜0.01),而表达Myb及BCL-6的水平均明显减低(P＜0.01).MDA-7/IL-24过表达组裸鼠模型Raji细胞移植瘤质量明显低于对照组[(1.23±0.21)vs(1.96±0.24)g,P＜0.01].结论:转染MDA-7/IL-24可能通过诱导分化作用抑制Burkitt淋巴瘤细胞的生物活性.     

过表达MDA-7/IL-24蛋白的亚细胞定位

目的了解标签蛋白GFP的位置对过表达的MDA-7/IL-24融合蛋白亚细胞定位的影响。方法分别构建在MDA-7/IL-24 cDNA的5'端和3'端带有GFP-tag的重组表达质粒pEGFP-C1-mda-7/IL-24和pEGFP-N3-mda-7/IL-24,瞬时转染猴胚肾Cos7细胞,48h后用Hoechst 33258染核,在荧光显微镜下观察GFP-MDA-7/IL-24融合蛋白在Cos7细胞的亚细胞分布。结果测序表明重组质粒pEGFP-C1-mda-7/IL-24和pEGFP-N3-mda-7/IL-24构建正确;分别转染Cos7细胞后,在氨基端带有GFP-tag的MDA-7/IL-24融合蛋白表达阳性细胞中,绿色荧光均匀分布于胞浆和胞核,但在羧基端带有GFP-tag的MDA-7/IL-24融合蛋白表达阳性细胞中,绿色荧光则分布于核膜外侧和胞浆。结论GFP-tag位置的不同对过表达融合蛋白MDA-7/IL-24的亚细胞定位有显著的影响。     

人mda-7/IL-24对淋巴瘤细胞Namalwa的抑制作用

目的:研究黑素瘤分化相关基因-7(melanoma differentiation associated gene-7,mda-7,又称IL-24)对淋巴瘤细胞系Namalwa细胞的抑制作用。方法:用半定量RT-PCR方法检测10个造血系统恶性肿瘤细胞系(Namalwa、Raji、K562、NB4、U937、Ramous、CEM、KG1a、HL60、J6-1)中mda-7/IL-24的表达情况。用RT-PCR方法从活化的人外周血单个核细胞(PBMC)中克隆mda-7/IL-24编码区,构建真核表达载体pTarget-IL-24。经测序鉴定后,用脂质体法转染Namalwa细胞,筛选稳定表达细胞株。转染细胞经RT-PCR和Western blotting证实mda-7/IL-24的表达。通过MTF法、集落形成试验、流式细胞术、裸鼠体内成瘤实验来评价mda-7/IL-24对肿瘤细胞增殖、生长特性、集落形成、凋亡情况、体内致瘤能力的作用。结果:10个造血系统恶性肿瘤细胞系中未检测到mda-7/IL-24的表达;转染重组质粒pTarget-IL-24的Namalwa细胞在mRNA与蛋白水平都有mda-7/IL-24的表达;稳定表达mda-7/IL-24的Namalwa细胞增殖活力以及集落形成能力与转染空载体的对照组相比明显下降(P<0.05);但是两者的凋亡率比较无统计学意义。裸鼠体内移植瘤实验结果显示稳定表达mda-7/IL-24的Namalwa细胞株的致瘤性明显低于转染空载体的对照组(P<0.05)。结论:mda-7/IL-24对来源于Burkitt淋巴瘤的Namalwa细胞系具有明显的增殖抑制作用,为Burkitt淋巴瘤的基因治疗提供了新的思路。     

Combining histone deacetylase inhibitors with MDA-7/IL-24 enhances killing of renal carcinoma cells

In the present study we show that histone deacetylase inhibitors (HDACIs) enhance the anti-tumor effects of melanoma differentiation associated gene-7/interleukin 24 (mda-7/IL-24) in human renal carcinoma cells. Similar data were obtained in other GU tumor cells. Combination of these two agents resulted in increased autophagy that was dependent on expression of ceramide synthase 6, with HDACIs enhancing MDA-7/IL-24 toxicity by increasing generation of ROS and Ca²⁺. Knock down of CD95 protected cells from HDACI and MDA-7/IL-24 lethality. Sorafenib treatment further enhanced (HDACI + MDA-7/IL-24) lethality. Anoikis resistant renal carcinoma cells were more sensitive to MDA-7/IL-24 that correlated with elevated SRC activity and tyrosine phosphorylation of CD95. We employed a recently constructed serotype 5/3 adenovirus, which is more effective than a serotype 5 virus in delivering mda-7/IL-24 to renal carcinoma cells and which conditionally replicates (CR) in tumor cells expressing MDA-7/IL-24 by virtue of placing the adenoviral E1A gene under the control of the cancer-specific promoter progression elevated gene-3 (Ad.5/3-PEG-E1A-mda-7; CRAd.5/3-mda-7, Ad.5/3-CTV), to define efficacy in renal carcinoma cells. Ad.5/3-CTV decreased the growth of renal carcinoma tumors to a significantly greater extent than did a non-replicative virus Ad.5/3-mda-7. In contralateral uninfected renal carcinoma tumors Ad.5/3-CTV also decreased the growth of tumors to a greater extent than did Ad.5/3-mda-7. In summation, our data demonstrates that HDACIs enhance MDA-7/IL-24-mediated toxicity and tumor specific adenoviral delivery and viral replication of mda-7/IL-24 is an effective pre-clinical renal carcinoma therapeutic.     

Stabilization of MDA-7/IL-24 for colon cancer therapy

Colon cancer is one of the most commonly diagnosed cancers in the United States. Recombinant MDA-7/IL-24 has showed its selective cytotoxicity against cancer cells, and Ad-mda7 (INGN-241) is currently under clinical investigation for solid tumors. Here, we investigated the expression of MDA-7/IL-24 in colorectal cancer (CRC) tissues from 202 patients. Compared with the adjacent mucosa, CRC tissues displayed significantly lower MDA-7/IL-24 levels. The MDA-7/IL-24 levels in CRC were significantly associated with patients’ survival rate in a 6-year period. These results indicate MDA-7/IL-24 level is both a diagnostic and prognostic biomarker for CRC, and support the role of MDA-7/IL-24 in the treatment of CRC. To elevate MDA-7/IL-24 level for colon cancer treatment, we successfully developed a small-molecule compound SC144 with the ability to up-regulate MDA-7/IL-24 expression via direct binding and stabilizing MDA-7/IL-24 in human colon cancer cells. Among the analogs tested, SC144 exhibited the highest cytotoxicity in a panel of colon cancer cell lines in a p53-independent manner, accompanied by cell cycle arrest in G₀/G₁ with downregulation of Cyclin D1 levels, and apoptosis induction with upregulation of cell surface-bound Fas/CD95. These results combined with our previous studies support the anticancer role of MDA-7/IL-24 as well as the clinical development of SC144 for colon cancer treatment.     

A novel oncogenic pathway by TLS-CHOP involving repression of MDA-7/IL-24 expression

Background:

Translocated in liposarcoma-CCAAT/enhancer binding protein homologous protein (TLS–CHOP) (also known as FUS-DDIT3) chimeric oncoprotein is found in the majority of human myxoid liposarcoma (MLS), but its molecular function remains unclear.

Methods:

We knockdowned TLS–CHOP expression in MLS-derived cell lines by a specific small interfering RNA, and analysed the gene expression profiles with microarray.

Results:

TLS-CHOP knockdown inhibited growth of MLS cells, and induced an anticancer cytokine, melanoma differentiation-associated gene 7 (MDA-7)/interleukin-24 (IL-24) expression. However, double knockdown of TLS–CHOP and MDA-7/IL-24 did not inhibit MLS cell growth.

Conclusion:

Repression of MDA-7/IL-24 expression by TLS–CHOP is required for MLS tumour growth, and TLS–CHOP may become a promising therapeutic target for MLS treatment.     

MDA-7/IL-24 functions as a tumor suppressor gene in vivo in transgenic mouse models of breast cancer

Melanoma differentiation associated gene-7/Interleukin-24 (MDA-7/IL-24) is a novel member of the IL-10 gene family that selectively induces apoptosis and toxic autophagy in a broad spectrum of human cancers, including breast cancer, without harming normal cells or tissues. The ability to investigate the critical events underlying cancer initiation and progression, as well as the capacity to test the efficacy of novel therapeutics, has been significantly advanced by the development of genetically engineered mice (GEMs) that accurately recapitulate specific human cancers. We utilized three transgenic mouse models to better comprehend the in vivo role of MDA-7/IL-24 in breast cancer. Using the MMTV-PyMT spontaneous mammary tumor model, we confirmed that exogenously introducing MDA-7/IL-24 using a Cancer Terminator Virus caused a reduction in tumor burden and also produced an antitumor “bystander” effect. Next we performed xenograft studies in a newly created MMTV-MDA-7 transgenic model that over-expresses MDA-7/IL-24 in the mammary glands during pregnancy and lactation, and found that MDA-7/IL-24 overexpression delayed tumor growth following orthotopic injection of a murine PDX tumor cell line (mPDX) derived from a tumor formed in an MMTV-PyMT mouse. We also crossed the MMTV-MDA-7 line to MMTV-Erbb2 transgenic mice and found that MDA-7/IL-24 overexpression delayed the onset of mammary tumor development in this model of spontaneous mammary tumorigenesis as well. Finally, we assessed the role of MDA-7/IL-24 in immune regulation, which can potentially contribute to tumor suppression in vivo. Our findings provide further direct in vivo evidence for the role of MDA-7/IL-24 in tumor suppression in breast cancer in immune-competent transgenic mice.     

白细胞介素-24抑制K562细胞生长的机制

 目的　探讨白细胞介素-24（又称黑色素瘤分化相关基因-7,IL-24／mda-7）对白血病细胞系K562的周期阻滞作用机制。方法　利用基因芯片技术初步分析转染IL-24／mda-7与转染空载体的K562细胞之间基因表达差异,并以实时定量PCR验证;以Western blotting方法检测pRb的磷酸化水平。结果　转染IL-24／mda-7可使K562细胞的细胞周期相关基因p21WAF-1、BCCIP上调,cdk6、Smurf2下调,定量PCR证实了上述表达变化;IL-24／mda-7转染还可明显降低K562细胞pRb磷酸化水平。结论　IL-24／mda-7 可能通过调节细胞周期相关蛋白,即上调p21WAF-1、BCCIP,下调cdk6、Smurf2,使K562阻滞于G0／G1期,从而抑制细胞生长。