• Title/Summary/Keyword: siRNA

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Down-Regulation of Mcl-1 by Small Interference RNA Induces Apoptosis and Sensitizes HL-60 Leukemia Cells to Etoposide

  • Karami, Hadi;Baradaran, Behzad;Esfehani, Ali;Sakhinia, Masoud;Sakhinia, Ebrahim
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.2
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    • pp.629-635
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    • 2014
  • Background: Acute myeloid leukemia (AML) is a fatal hematological malignancy which is resistant to a variety of chemotherapy drugs. Myeloid cell leukemia-1 (Mcl-1), a death-inhibiting protein that regulates apoptosis, has been shown to be overexpressed in numerous malignancies. In addition, it has been demonstrated that the expression level of the Mcl-1 gene increases at the time of leukemic relapse following chemotherapy. The aim of this study was to target Mcl-1 by small interference RNA (siRNA) and analyze its effects on survival and chemosensitivity of acute myeloid leukemia cell line HL-60. Materials and Methods: siRNA transfection was performed with a liposome approach. The expression levels of mRNA and protein were measured by real-time quantitative PCR and Western blot analysis, respectively. Trypan blue assays were performed to evaluate tumor cell growth after siRNA transfection. The cytotoxic effects of Mcl-1 siRNA (siMcl-1) and etoposide were determined using MTT assay on their own and in combination. Apoptosis was quantified using a DNA-histone ELISA assay. Results: Transfection with siMcl-1 significantly suppressed the expression of Mcl-1 mRNA and protein in a time-dependent manner, resulting in strong growth inhibition and spontaneous apoptosis. Surprisingly, pretreatment with siMcl-1 synergistically enhanced the cytotoxic effect of etoposide. Furthermore, Mcl-1 down-regulation significantly increased apoptosis sensitivity to etoposide. No significant biological effects were observed with negative control siRNA treatment. Conclusions: Our results suggest that specific suppression of Mcl-1 by siRNA can effectively induce apoptosis and overcome chemoresistance of leukemic cells. Therefore, siMcl-1 may be a potent adjuvant in leukemia chemotherapy.

Effects of PTTG Down-regulation on Proliferation and Metastasis of the SCL-1 Cutaneous Squamous Cell Carcinoma Cell Line

  • Xia, Yong-Hua;Li, Min;Fu, Dan-Dan;Xu, Su-Ling;Li, Zhan-Guo;Liu, Dong;Tian, Zhong-Wei
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.11
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    • pp.6245-6248
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    • 2013
  • Aims: To study effects of down-regulation of pituitary tumor-transforming gene (PTTG) on proliferation and metastasis ability of the SCL-1 cutaneous squamous cell carcinoma (CSCC) cell line and explore related mechanisms. Methods: SCL-1 cells were divided into 3 groups (untreated, siRNA control and PTTG siRNA). Cell proliferation assays were performed using a CCK-8 kit and proliferation and metastasis ability were analyzed using Boyden chambers. In addition, expression of MMP-2 and MMP-9 was detected by r-time qPCR and Western blotting. Results: Down-regulation of PTTG could markedly inhibit cell proliferation in SCL-1 cells, compared to untreated and control siRNA groups (P < 0.05). Real-time qPCR demonstrated that expression levels of PTTG, MMP-2 and MMP-9 in the PTTG siRNA group were 0.8%, 23.2% and 21.3% of untreated levels. Western blotting revealed that expression of PTTG, MMP-2 and MMP-9 proteins in the PTTG siRNA group was obviously down-regulated. The numbers of migrating cells ($51.38{\pm}4.71$) in the PTTG siRNA group was obviously lower than that in untreated group ($131.33{\pm}6.12$) and the control siRNA group ($127.72{\pm}5.20$) (P < 0.05), suggesting that decrease of proliferation and metastasis ability mediated by PTTG knock-down may be closely correlated with down-regulation of MMP-2 and MMP-9 expression. Conclusion: Inhibition of PTTG expression may be a new target for therapy of CSCC.

Decreases in $Casz1$ mRNA by an siRNA Complex Do not Alter Blood Pressure in Mice

  • Ji, Su-Min;Shin, Young-Bin;Park, So-Yon;Lee, Hyeon-Ju;Oh, Berm-Seok
    • Genomics & Informatics
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    • v.10 no.1
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    • pp.40-43
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    • 2012
  • Recent genomewide association studies of large samples have identified genes that are associated with blood pressure. The Global Blood Pressure Genetics (Global BPgen) and Cohorts for Heart and Aging Research in Genome Epidemiology (CHARGE) consortiums identified 14 loci that govern blood pressure on a genomewide significance level, one of which is $CASZ1$ confirmed in both Europeans and Asians. $CASZ1$ is a zinc finger transcription factor that controls apoptosis and cell fate and suppresses neuroblastoma tumor growth by reprogramming gene expression, like a tumor suppressor. To validate the function of $CASZ1$ in blood pressure, we decreased $Casz1$ mRNA levels in mice by siRNA. $Casz1$ siRNA reduced mRNA levels by 59% in a mouse cell line. A polyethylenimine-mixed siRNA complex was injected into mouse tail veins, reducing $Casz1$ mRNA expression to 45% in the kidney. However, blood pressure in the treated mice was unaffected, despite a 55% reduction in $Casz1$ mRNA levels in the kidney on multiple siRNA injections daily. Even though $Casz1$ siRNA-treated mice did not experience any significant change in blood pressure, our study demonstrates the value of $in$ $vivo$ siRNA injection in analyzing the function of candidate genes identified by genomewide association studies.

Adipocyte-Related Genes and Transcription Factors were Affected by siRNA for Aromatase Gene during 3T3-L1 Differentiation (지방세포 분화중인 3T3-L1 세포에서 아로마테이즈 siRNA 처리에 의한 지방관련 유전자와 전사인자의 발현 조절)

  • Jeong, Dong-Kee
    • Journal of Life Science
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    • v.18 no.11
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    • pp.1600-1605
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    • 2008
  • This study was performed to verify the gene expression of 3T3-L1 using the siRNA of the aromatase gene, which is the estrogen synthesis enzymes. First of all three pairs of siRNA were designed from the CYP19A1 (aromatase) and analyzed the formation of fat cell mechanism by transferring gene to 3T3-L1 and differentiating it. As a result, the expression of leptin gene, which is the main gene causing the obesity, was controlled and the cause of the obesity is related with the insulin specifically. The overexpression of adiponectin and adipsin was observed. This result showed that the formation of the fat was controlled a little without any side effect by obstructing a specific material out of all the signal systems in the fat formation. This study will be an important clue to make it clear that the lack or overexpression of estrogen might be the cause of fat formation mechanism.

Inhibition of c-FLIP by RNAi Enhances Sensitivity of the Human Osteogenic Sarcoma Cell Line U2OS to TRAILInduced Apoptosis

  • Zhang, Ya-Ping;Kong, Qing-Hong;Huang, Ying;Wang, Guan-Lin;Chang, Kwen-Jen
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.6
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    • pp.2251-2256
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    • 2015
  • To study effects of cellular FLICE (FADD-like IL-$1{\beta}$-converting enzyme)-inhibitory protein (c-FLIP) inhibition by RNA interference (RNAi) on sensitivity of U2OS cells to tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL)-induced apoptosis, plasmid pSUPER-c-FLIP-siRNA was constructed and then transfected into U2OS cells. A stable transfection cell clone U2OS/pSUPER-c-FLIP-siRNA was screened from the c-FLIP-siRNA transfected cells. RT-PCR and Western blotting were applied to measure the expression of c-FLIP at the levels of mRNA and protein. The results indicated that the expression of c-FLIP was significantly suppressed by the c-FLIP-siRNA in the cloned U2OS/pSUPER-c-FLIP-siRNA as compared with the control cells of U2OS/pSUPER. The cloned cell line of U2OS/pSUPER-c-FLIP-siRNA was further examined for TRAILinduced cell death and apoptosis in the presence of a pan-antagonist of inhibitor of apoptosis proteins (IAPs) AT406, with or without 4 hrs pretreatment with rocaglamide, an inhibitor of c-FLIP biosynthesis, for 24 hrs. Cell death effects and apoptosis were measured by the methods of MTT assay with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and flow cytometry, respectively. The results indicated that TRAIL-induced cell death in U2OS/pSUPER-c-FLIP-siRNA was increased compared with control cells U2OS/pSUPER in the presence or absence of AT406. Flow cytometry indicated that TRAIL-induced cell death effects proceeded through cell apoptosis pathway. However, in the presence of rocaglamide, cell death or apoptotic effects of TRAIL were similar and profound in both cell lines, suggesting that the mechanism of action for both c-FLIP-siRNA and rocaglamide was identical. We conclude that the inhibition of c-FLIP by either c-FLIP-siRNA or rocaglamide can enhance the sensitivity of U2OS to TRAIL-induced apopotosis, suggesting that inhibition of c-FLIP is a good target for anti-cancer therapy.

HiF-1α siRNA and Cisplatin in Combination SuppressTumor Growth in a Nude Mice Model of Esophageal Squamous Cell Carcinoma

  • Liao, Hong-Ying;Wang, Gui-Ping;Gu, Li-Jia;Huang, Shao-Hong;Chen, Xiu-Ling;Li, Yun;Cai, Song-Wang
    • Asian Pacific Journal of Cancer Prevention
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    • v.13 no.2
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    • pp.473-477
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    • 2012
  • Introduction: The esophagus squamous cell carcinoma (ESCC) is one of the most deadly malignances, and a current challenge is the development of effective therapeutic agents. Our present work addressed the effect of HIF-$1{\alpha}$ siRNA alone or in combination with cisplatin on the growth of ESCC in nude mice. Materials and Methods: Xenografts were established by inoculating ESCC TE-1 cells in nude mice, and transplanted tumors were treated with HIF-$1{\alpha}$ siRNA, cisplatin alone or together. Growth was assessed by measuring tumor volume. HIF-$1{\alpha}$ mRNA and protein expression were detected using RT-PCR and immunohistochemistry, respectively. Apoptosis of ESCC TE-1 cells was analyzed by flow cytometry. Results: In our nude mice model, HIF-$1{\alpha}$ siRNA effectively inhibited the growth of transplanted ESCC, downregulating HIF-$1{\alpha}$ mRNA and protein expression, and inducing ESCC TE-1 cell apoptosis. Notably when combinated with cisplatin, HIF-$1{\alpha}$ siRNA showed synergistic interaction in suppressing tumor growth. Furthermore, the proportion of apoptotic cells in HIF-$1{\alpha}$ siRNA plus cisplatin group was significantly higher than that in cisplatin or HIF-$1{\alpha}$ siRNA-treated groups (P<0.05). Conclusions: Down-regulated HIF-$1{\alpha}$ expression induced by siRNA could effectively suppress the growth of transplanted ESCC $in$ $vivo$. HIF-$1{\alpha}$ siRNA could enhance the cytotoxicity of cisplatin, which suggests that a combination of these two agents may have potential for therapy of advanced ESCC.

Effects of Down-regulation of HDAC6 Expression on Proliferation, Cell Cycling and Migration of Esophageal Squamous Cell Carcinoma Cells and Related Molecular Mechanisms

  • Li, Ning;Tie, Xiao-Jing;Liu, Pei-Jie;Zhang, Yan;Ren, Hong-Zheng;Gao, Xin;Xu, Zhi-Qiao
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.2
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    • pp.685-689
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    • 2013
  • Objective: To study the effects of down-regulation of HDAC6 expression on proliferation, cell cycling and migration of esophageal squamous cell carcinoma (ESCC) cells and related molecular mechanisms. Methods: ESCC cell line EC9706 cells were randomly divided into untreated (with no transfection), control siRNA (transfected with control siRNA) and HDAC6 siRNA (transfected with HDAC6 small interfering RNA) groups. Effects of HDAC6 siRNA interference on expression of HDAC6 mRNA and protein in EC9706 cells were investigated by semi-quantitative RT-PCR, Western blotting and immunocytochemistry methods. Effects of down-regulation of HDAC6 expression on cell proliferation, cell cycle, and cell migration were studied using a CCK-8 kit, flow cytometry and Boyden chambers, respectively. Changes of mRNA and protein expression levels of cell cycle related factor (p21) and cell migration related factor (E-cadherin) were investigated by semi-quantitative RT-PCR and Western blotting methods. Results: After transfection of HDAC6 siRNA, the expression of HDAC6 mRNA and protein in EC9706 cells was significantly downregulated. In the HDAC6 siRNA group, cell proliferation was markedly inhibited, the percentage of cells in G0/G1 phase evidently increased and the percentage of cells in S phase decreased, and the number of migrating cells significantly and obviously decreased. The mRNA and protein expression levels of p21 and E-cadherin in the HDAC6 siRNA group were significantly higher than those in the untreated group and the control siRNA group, respectively. Conclusions: HDAC6 siRNA can effectively downregulate the expression of HDAC6 mRNA and protein in EC9706 cells. Down-regulation of HDAC6 expression can obviously inhibit cell proliferation, arrest cell cycling in the G0/G1 phase and reduce cell migration. The latter two functions may be closely related with the elevation of mRNA and protein expression of p21 and E-cadherin.

Effects of Hepatocyte Growth Factor on the PSA Signaling Pathway of U-251-MG Cells (U-251-MG 세포에서 PSA 경로에 작용하는 Hepatocyte Growth Factor의 효과)

  • Kim, Hwan-Gyu
    • KSBB Journal
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    • v.24 no.5
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    • pp.425-431
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    • 2009
  • Hepatocyte growth factor (HGF) and its receptor play an important role in the formation and progression of glioma. In this study, I investigated the ability of HGF to recover of the PSA siRNA-suppressed cell proliferation, migration and invasion in U-251-MG cells. PSA siRNA-transfected U-251-MG cells showed the reduction of the proliferation, migration and invasion with compared to control. Treatment of HGF on the PSA siRNA-transfected U-251-MG cells recovered the ability of proliferation, migration and invasion. These data suggest that PSA and HGF may use unique and parallel signaling cascade leading to the proliferative, migrative and invasive phenotype of U-251-MG cells. I also showed that PSA cooperated with HGF to a migrative and invasive phenotype via the increased secretion of matrix metalloproteinase-2 (MMP-2) and MMP-9.

Inhibition of Cervical Cancer Cell Growth by Gene Silencing of HPV16 E6 Induced by Short-interfering RNA

  • Park, Sang-Muk;Lee, Sun-Kyung;Kim, Yoon-Sik
    • Korean Journal of Clinical Laboratory Science
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    • v.43 no.3
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    • pp.89-97
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    • 2011
  • The Human Papilloma Virus (HPV) infection has been strongly associated with pathogenesis of uterine cervix carcinoma. HPV type 16, a causative agent of uterine cervix carcinoma, encodes the E6 and E7 oncogenes, expression of which is pivotal for malignant transformation and maintenance of malignant phenotypes. To develop a gene therapy for HPV-related carcinoma, We investigated the effect of E6 short-interfering RNA (E6 siRNA) on the expression of this oncogene and on the growth of HPV 16-related uterine cervix carcinoma cells. SiHa cells, a uterine cervix carcinoma cell line, which contain a single copy of HPV 16 integrated in the chromosome and express the E6 and E7 oncogenes. Before 24 hr of transfection, cells were seeded and transfected with control plasmid or E6 siRNA-expressing plasmid. The mRNA was analysed by reverse transcriptase polymerase chain reaction (RT-PCR). The cell growth rate was investigated by MTT method. The E6 mRNA level in SiHa cells was decreased in HPV 16 E6 siRNA-expression vector transfected cells and a decrease in the growth of these cells was also observed. From these results. it is evident that E6 siRNA played a role in suppression of growth of SiHa cells and has a fair chance as a candidate for gene specific therapy for HPV related uterine cervix carcinoma.

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Effect of MUC1 siRNA on Drug Resistance of Gastric Cancer Cells to Trastuzumab

  • Deng, Min;Jing, Da-Dao;Meng, Xiang-Jun
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.1
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    • pp.127-131
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    • 2013
  • Trastuzumab is the first molecular targeting drug to increase the overall survival rate in advanced gastric cancer. However, it has also been found that a high intrinsic or primary trastuzumab resistance exists in some proportion of gastric cancer patients. In order to explore the mechanism of resistance to trastuzumab, firstly we investigated the expression of MUC1 (membrane-type mucin 1) in gastric cancer cells and its relationship with drug-resistance. Then using gene-silencing, we transfected a siRNA of MUC1 into drug-resistant cells. The results showed the MKN45 gastric cell line to be resistant to trastuzumab, mRNA and protein expression of MUC1 being significantly upregulated. After transfection of MUC1 siRNA, protein expression of MUC1 in MKN45cells was significantly reduced. Compared with the junk transfection and blank control groups, the sensitivity to trastuzumab under MUC1 siRNA conditions was significantly increased. These results imply that HER2-positive gastric cancer cell MKN45 is resistant to trastuzumab and this resistance can be cancelled by silencing expression of the MUC1 gene.