MDA-7/IL-24 suppresses human ovarian carcinoma growth in vitro and in vivo

Background  

Previous studies showed that the human melanoma differentiation-associated gene-7 (mda-7), also known as interleukin-24 (IL-24), has potent antitumor activity against human and murine cancer cells. However, the majority of these studies were limited to in vitro testing. In the present study, we investigated the antitumor activity of mda-7/IL-24 against human ovarian cancer cells both in vitro and in vivo.     

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。     

Unique aspects of mda-7/IL-24 antitumor bystander activity: establishing a role for secretion of MDA-7/IL-24 protein by normal cells

Melanoma differentiation associated gene-7 (mda-7) was cloned using subtraction hybridization from terminally differentiated human melanoma cells. Based on structural and functional properties, mda-7 is now recognized as interleukin-24 (IL-24), a new member of the expanding IL-10 gene family. Unique properties of mda-7/IL-24 include its ability to selectively induce growth suppression, apoptosis and radiosensitization in diverse human cancer cells, without causing similar effects in normal cells. The utility of mda-7/IL-24, administered by means of a replication-incompetent adenovirus, as a gene therapy for cancer has recently received validation in patients, highlighting an important phenomenon initially observed in pancreatic tumor cells, namely a 'potent bystander apoptosis-inducing effect' in adjacent tumor cells not initially receiving this gene product. We presently investigated the contribution of mda-7/IL-24 secreted by normal cells in mediating this 'bystander effect', and document that normal cells induced to produce mda-7/IL-24 following infection with recombinant adenoviruses expressing this cytokine secrete mda-7/IL-24, which modifies the anchorage-independent growth, invasiveness, survival and sensitivity to radiation of cancer cells that contain functional IL-20/IL-22 receptors, but not in cancer cells that lack a complete set of receptors. Moreover, the combination of secreted mda-7/IL-24 and radiation engenders a 'bystander antitumor effect' not only in inherently mda-7/IL-24 or radiation-sensitive cancer cells, but also in tumor cells overexpressing the antiapoptotic proteins bcl-2 or bcl-x(L) and displaying resistance to either treatment alone. The present studies provide definitive evidence that secreted mda-7/IL-24 from normal cells can induce direct antitumor and radiation-enhancing effects that are dependent on the presence of canonical receptors for this cytokine on tumor cells. Moreover, we now describe a novel means of enhancing mda-7/IL-24's therapeutic potential by targeting normal cells to produce and release this cancer-specific apoptosis-inducing cytokine, a strategy that could be employed as an innovative way of using this unique gene product for treating metastatic disease.     

MDA-7/IL-24, a novel tumor suppressor/cytokine is ubiquitinated and regulated by the ubiquitin-proteasome system, and inhibition of MDA-7/IL-24 degradation enhances the antitumor activity

Steady-state protein levels are determined by the balance between protein synthesis and degradation. Protein half-lives are determined primarily by degradation, and the major degradation pathways involve either lysosomal destruction or an ATP-dependent process involving ubiquitination to target proteins to the proteosome. Studies have shown that multiple tumor-suppressor proteins are ubiquitinated and degraded by the 26S proteasome. In the present study, we investigated whether the tumor suppressor/cytokine melanoma differentiation-associated gene-7/interleukin-24 gene (MDA-7/IL-24) protein is ubiquitinated and its degradation controlled by the proteasome. Treatment of ovarian (2008) and lung (H1299) tumor cells with adenoviral delivery of mda-7 (Ad-mda7) or Ad-mda7 plus the proteosome inhibitor MG132 showed that MDA-7 protein expression was dependent upon proteosome activity. Western blot and immunoprecipitation analyses verified that the MDA-7 protein was ubiquitinated and that ubiquitinated-MDA-7 levels were increased in MG132-treated cells. These results were confirmed using small interfering RNA (siRNA)-mediated knockdown of ubiquitin. Furthermore, ubiquitinated MDA-7 protein was degraded by the 26S proteasome, as MDA-7 accumulation was observed only when cells were treated with MG132 but not with lysosome or protease inhibitors. Inhibition of the catalytic beta-5 subunit of the 20S proteasome using siRNA resulted in MDA-7 protein accumulation. Finally, treatment of tumor cells with Ad-mda7 plus the proteasome inhibitor bortezomib resulted in increased tumor cell killing. Our results show that MDA-7/IL-24 is ubiquitinated and degraded by the 26S proteasome. Furthermore, inhibition of MDA-7 degradation results in enhanced tumor killing, identifying a novel anticancer strategy.     

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.     

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 plus radiation enhance survival in animals with intracranial primary human GBM tumors

Melanoma differentiation associated gene-7/interleukin 24 (mda-7/IL-24) is a cytokine displaying selective apoptosis-inducing activity in tumors, including glioblastoma (GBM), without damaging normal cells. The present studies focused on defining whether an adenovirus expressing MDA-7/IL-24, Ad.mda-7, infused into pre-formed invasive primary human GBM tumors growing in athymic mouse brains altered tumor cell growth and animal survival, and whether Ad.mda-7 radiosensitized GBM cells and enhanced the survival benefit of irradiation. Ad.mda-7 directly radiosensitized glioma cells in vitro in a JNK1-3- and caspase 9-dependent fashion and demonstrated bystander-effect killing and radiosensitization of GBM cells when primary human astrocytes were infected with Ad.mda-7. Infusion of Ad.mda-7 into pre-formed glioma tumors caused a rapid decrease in proliferation and blood vessel density and an increase in cell killing. Irradiation of Ad.mda-7 infected tumors enhanced cell death. Cell killing correlated with pro-caspase 3 cleavage, enhanced phosphorylation of JNK1-3 and reduced phosphorylation of ERK1/2. Ad.mda-7 enhanced the survival of animals implanted with GBM6 and GBM12 tumors, and significantly increased the survival benefit of irradiation in animals bearing GBM12 tumors. Ad.mda-7 toxicity was evident against CD133+ and CD133- GBM cells; upon tumor re-growth approximately 70-100 days after virus infusion, the relative CD133+ level within the tumor was profoundly reduced with lower Ki67 reactivity and increased beta-galactosidase staining. Infusion of Ad.mda-7 into an immune competent rat brain did not cause normal tissue toxicity 1-4 weeks after infusion using T1 and T2 weighted MRI and H&E staining. Our data demonstrate that Ad.mda-7 prolongs the survival of animals bearing GBM tumors and does so through multiple mechanisms including direct tumor cell killing and selection for surviving cells that are more differentiated and potentially displaying a putatively senescent phenotype.     

Expression of MDA-7/IL-24 and its clinical significance in resected non-small cell lung cancer.

PURPOSE: The melanoma differentiation-associated gene-7 (MDA-7) protein, also known as interleukin (IL)-24, is a novel candidate of tumor suppressor that can induce apoptosis experimentally in a variety of human malignant cells including lung cancer cells. However, only one clinical study has documented that MDA-7/IL-24 expression is down-regulated with progression of melanoma. Thus, the present study was conducted to assess the clinical significance of MDA-7/IL-24 expression in non-small cell lung cancer. EXPERIMENTAL DESIGN: A total of 183 consecutive patients with resected pathologic stage I-IIIA, non-small cell lung cancer were retrospectively reviewed, and immunohistochemical staining was used to detect MDA-7/IL-24 expression. RESULTS: MDA-7/IL-24 expression was high in 97 (53.0%) patients and low in the other patients. There was no significant correlation between MDA-7/IL-24 status and any patients' characteristic including pathologic stage. There was no significant difference in tumor angiogenesis or proliferative activity according to MDA-7/IL-24 status, but MDA-7/IL-24-high adenocarcinoma showed a significantly higher incidence of apoptotic tumor cell death than MDA-7/IL-24-low adenocarcinoma. MDA-7/IL-24-high patients seemed to show a favorable postoperative prognosis as compared with MDA-7/IL-24-low patients (5-year survival rates, 75.9% and 62.0%, respectively), although the difference did not reach a statistical significance (P = 0.061). Subset analyses showed that positive MDA-7/IL-24 expression was a significant factor to predict a favorable prognosis in adenocarcinoma (P = 0.033), which was confirmed by a multivariate analysis; there was no difference in the prognosis according to MDA-7/IL-24 status in squamous cell carcinoma. CONCLUSIONS: MDA-7/IL-24 status was a significant prognostic factor in lung adenocarcinoma, not in lung squamous cell carcinoma.     

mda-7/IL-24 induces apoptosis in human GBC-SD gallbladder carcinoma cells via mitochondrial apoptotic pathway

mda-7/IL-24 has tumor-suppressor activity in a broad spectrum of human cancer cells. However, the therapeutic effect of the recombinant human IL-24 protein on human gallbladder carcinoma has rarely been explored. In this study, we used a human gallbladder carcinoma cell line (GBC-SD) to explore the effect of adenovirus-mediated IL-24 (Ad-IL24) gene therapy on GBC-SD cells. We show that Ad-IL24 treatment of GBC-SD cells in vitro conspicuously induced apoptosis of GBC-SD cells. We also demonstrate that the in vivo treatment of GBC tumor-bearing athymic nude mice intratumorally injected with Ad-IL24 significantly suppressed GBC growth. To further explore the mechanism that mda-7/IL-24 utilized in tumor cell apoptosis, we examined molecules and pathways involved in apoptotic regulation and found that Ad-IL24 induced the down-regulation of anti-apoptotic gene Bcl-2 and the release of cytochrome c, which subsequently activated caspase-9, caspase-3 and PARP to induce apoptosis. In summary, adenovirus (AdV)-mediated IL-24 overexpression exerted potent antitumor activity via stimulating mitochondrial apoptotic pathway in GBC-SD. Therefore, mda-7/IL-24 has the potential to serve as a tool for targeted gene therapy in the treatment of gallbladder cancer.     

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.     

Akt/c-Myc通路对胃癌细胞化疗效果的影响

背景与目的：Akt信号通路是调节原癌基因c-myc蛋白表达水平的主要机制之一,Akt信号通路激活后可降低胃癌细胞的化疗敏感性。然而,目前对Akt/c-Myc通路在胃癌化疗过程中的作用尚不明确。因此,本课题通过观察Akt/c-Myc信号通路对胃癌细胞化疗效果的影响并探讨其作用机制。方法：依托泊苷作用于胃癌SGC7901和BGC823细胞,MTT法检测细胞的生存率;分别采用流式细胞仪和Hoechst33258荧光染色法检测细胞周期分布和凋亡;Akt活性的检测采用非放射性蛋白激酶活性分析法;Western印迹法检测c-Myc和p-AktSer473蛋白的表达水平;RT-PCR法检测c-MycmRNA的表达;同时观察PI3-K/Akt通路抑制剂Wortmannin对依托泊苷诱导的上述变化的影响。结果：依托泊苷呈时间-剂量依赖性抑制SGC7901和BGC823细胞的生长,明显诱导细胞的凋亡;同时上调SGC7901和BGC823细胞中Akt活性及p-AktSer473蛋白表达水平,并增强c-Myc蛋白和mRNA的表达。Wortmannin可明显增强依托泊苷的细胞生长抑制作用并提高细胞的凋亡水平;抑制依托泊苷诱导的c-Myc蛋白的表达,但对c-MycmRNA表达没有明显的影响。结论：依托泊苷激活SGC7901和BGC823细胞中的Akt信号通路,并上调c-Myc蛋白的表达水平而影响胃癌的化疗效果。Akt信号通路可能主要是通过转录后调节来调控c-Myc蛋白的水平。     

BiP/GRP78 is an intracellular target for MDA-7/IL-24 induction of cancer-specific apoptosis

Melanoma differentiation-associated gene-7/interleukin-24 (mda-7/IL-24) is a unique member of the IL-10 gene family that induces cancer-selective growth suppression and apoptosis in a wide spectrum of human cancers in cell culture and animal models. Additionally, recent clinical trials confirm safety and document significant clinical activity of mda-7/IL-24 in patients with diverse solid cancers and melanomas. Despite intensive study the molecular basis of tumor-cell selectivity of mda-7/IL-24 is not well characterized. Using deletion analysis, a specific mutant of MDA-7/IL-24, M4, consisting of amino acids 104 to 206, is described that retains the cancer-specific growth-suppressive and apoptosis-inducing properties of the full-length protein. Employing rationally designed mutational analysis, we show that MDA-7/IL-24 and M4 physically interact with BiP/GRP78 through their C and F helices, localize in the endoplasmic reticulum, and activate p38 MAPK and GADD gene expression, culminating in cancer-selective apoptosis. These studies provide novel mechanistic insights into the discriminating antitumor activity of MDA-7/IL-24 by elucidating BiP/GRP78 as a defined intracellular target of action and present an unparalleled opportunity to develop improved therapeutic versions of this cancer-specific apoptosis-inducing cytokine.     

MDA-7/IL-24基因与化疗药物联合应用对食管癌细胞产生协同抑制作用

探讨人黑素瘤分化相关基因7（melanoma differentiation-associated gene-7,MDA-7）/白介素-24(IL-24)基因对食管癌细胞的抑制作用及其与化疗药物的协同抗瘤作用。方法：RT-PCR法检测人食管癌细胞株TE-11和YES-5中MDA-7/IL-24受体IL-20R1、IL-20R2和IL-22R1的表达水平。用携带MDA-7/IL-24基因的重组人复制缺陷腺病毒Ad-MDA-7感染TE-11和YES-5细胞, Ad-LacZ为对照腺病毒,人成纤维细胞株OUMS-24为对照细胞。MTT法检测感染细胞抑制率,Western blotting法检测感染前后细胞中的MDA-7水平。化疗药物5-氟尿嘧啶（5-FU）、顺铂（CDDP）、丝裂霉素（MMC）和足叶乙甙（VP-16）分别与Ad-MDA-7联合作用于食管癌细胞株,MTT法检测单独或联合应用对食管癌细胞的抑制作用,流式细胞术检测Ad-MDA-7与化疗药单独或联合应用后食管癌细胞周期的变化,Western blotting检测Ad-MDA-7与化疗药联合作用后细胞凋亡和增殖的相关分子的变化。结果：TE-11和YES-5细胞均表达3种IL-24受体。Ad-MDA-7感染后,两种食管癌细胞中均有MDA-7蛋白表达,同时细胞均被剂量依赖性地抑制生长,Ad-MDA-7达3×104VP/细胞时TE-11细胞抑制率超过80%、YES-5细胞超过50%;同剂量Ad-LacZ对细胞无抑制作用,成纤维细胞OUMS-24被Ad-MDA-7感染后没有发生明显细胞抑制。Ad-MDA-7分别与5-FU、CDDP、MMC和VP-16联合应用后,与单独应用相比产生了更强的抗肿瘤协同效应。Ad-MDA-7与5-FU联合应用诱导细胞更多停滞在S和G2/M期,subG1期细胞比例明显增加。与单用5-FU相比,联合应用时Ad-MDA-7诱导了更多的细胞凋亡相关蛋白cleaved caspase-8、 -9、 -3的表达,增加了Akt的磷酸化,但降低了IκB-α的表达水平。结论：MDA-7/IL-24与化疗药联合应用于食管癌细胞,产生了更强的抗肿瘤协同效应,为临床化疗和基因治疗的联合应用提供新选择。     

TRPV4通过调控MAPK/ERK信号通路促进卵巢癌细胞的增殖和迁移北大核心

目的:探讨TRPV4通过影响MAPK/ERK信号通路调控卵巢癌细胞的增殖与迁移。方法:RT-qPCR和Western Blot方法检测TRPV4在卵巢癌细胞系和正常卵巢上皮细胞中的表达差异;GEPIA在线数据库分析卵巢癌患者TRPV4表达水平和预后关系;敲低TRPV4,通过RT-qPCR和Western Blot检测转染效率;通过细胞计数试剂盒(CCK8)、克隆形成实验以及Transwell迁移实验检测TRPV4在卵巢癌发生发展过程中增殖及迁移作用;通过GSEA软件富集分析信号通路并用Western Blot验证卵巢癌细胞MAPK/ERK信号通路表达量变化。结果:在卵巢癌细胞及临床组织样本中,TRPV4表达量明显增高,TRPV4表达量较高的患者预后更差。siRNA转染卵巢癌HO8910和Caov3细胞后,与Control组相比,TRPV4 mRNA和蛋白表达显著降低;细胞增殖迁移能力显著减弱;WB实验结果显示ERK总量不变,磷酸化水平降低,进一步实验中证实:敲低TRPV4后,ERK信号通路中的关键蛋白(P90RSK、MEK1/2、MSK1)磷酸化水平降低。结论:TRPV4在卵巢癌细胞及组织中高表达,可能通过正向调控MAPK/ERK信号通路,促进卵巢癌细胞增殖迁移等功能。     

Hedgehog signaling pathway regulates the growth of ovarian cancer spheroid forming cells

The hedgehog (Hh) pathway has been shown to be activated in numerous malignancies as well as in cancer stem cells. We sought to determine the importance of the Hh pathway in regulating growth and development of ovarian cancer spheroid-forming cells (SFCs). Ovarian cancer cell lines (ES2, TOV112D, OV90, and SKOV3) as well as a normal ovarian epithelial cell line (IOSE80) were grown in non-adherent growth conditions to form SFCs. Western blot analysis was used to determine the expression of Hh pathway proteins SMOH, PTCH, GLI1. SFCs were treated with Hh agonists (SHH and IHH) as well as an Hh inhibitor (cyclopamine) to determine changes in spheroid growth and survival. All ovarian cancer cell lines readily formed spheroids in non-adherent growth conditions while IOSE80 failed to form SFCs. Compared to IOSE80, ovarian cancer cell lines demonstrated significant activation of the Hh pathway as defined by increased expression of intranuclear GLI1. Both Hh agonists demonstrated significant increases in spheroid volume of at least 42-fold for SHH-treated cells and 46-fold for IHH-treated cells. With regard to survival, SFCs were 30-50% more resistant to cyclopamine than their corresponding monolayer cells. Despite this resistance, inhibition of the Hh pathway with cyclopamine prevented further growth of SFCs with a 10-, 5-, and 4-fold restriction in growth for ES2, SKOV3, and TOV112D, respectively. The hedgehog pathway appears to be important in regulating growth of ovarian cancer spheroid-forming cells. The activation and inhibition of this pathway demonstrates significant correlation to enhanced growth and growth restriction, respectively.