The effect of siRNA-Egr-1 and camptothecin on growth and chemosensitivity of breast cancer cell lines

Parra, Eduardo; Ferreira, Jorge

doi:10.3892/or_00000746

Cited by 23 publications

(30 citation statements)

References 37 publications

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“…In an effort to better understand the mechanisms responsible for these cellular responses, we measured the expression of Egr-1 protein and found that TGZ stimulates the expression of Egr-1 in a concentrationdependent manner. Egr-1 is a member of the immediate early gene response family and encodes a nuclear phosphoprotein involved in the regulation of cell growth and differentiation in response to signals such as mitogens, growth factors and stress stimuli (19)(20)(21). However, evidence suggests that Egr-1 binding sites are located within region -73 to -51 of the NAG-1 promoter, and the overexpression of Egr-1 results in increased NGA-1 expression.…”

Section: Discussionmentioning

confidence: 95%

Troglitazone induces apoptosis in gastric cancer cells through the NAG-1 pathway

Wang

Bai

2010

Mol Med Rep

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Abstract. The non-steroidal anti-inflammatory drug-activated gene (NAG-1) is a newly identified member of the transforming growth factor (TGF)-β superfamily and plays significant roles in regulating proliferation and pro-apoptotic activities. In the present study, we studied the regulation of NAG-1 by troglitazone in the cultured gastric cancer cell line BGC-823. MTT and TUNEL assays demonstrated that troglitazone potentially inhibits the proliferation of the gastric cancer cell line and induces apoptosis in vitro in a dose-and time-dependent manner. Troglitazone induced concentration-dependent NAG-1 expression in the BGC-823 cells, as assessed using immunocytochemistry. Furthermore, troglitazone increased Egr-1 protein levels in a concentration-dependent manner.In conclusion, the present study suggests that troglitazone markedly impedes proliferation and pro-apoptotic activities in BGC-823 cells, and the mechanism may partly be through the Egr-1 pathway.

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Section: Discussionmentioning

confidence: 95%

Troglitazone induces apoptosis in gastric cancer cells through the NAG-1 pathway

Wang

Bai

2010

Mol Med Rep

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“…At 14 days post treatment, plates were assessed for size and number of colonies (original magnification, x4). Colonies (in a representative field) are indicated (30,31).…”

Section: Methodsmentioning

confidence: 99%

“…Thermal cycle conditions were as follows: 42˚C for 30 min, 94˚C for 2 min, followed by 28 cycles of 94˚C 15 sec, 55˚C 30 sec, 72˚C 1 min, with a final extension at 72˚C for 10 min. RT-PCR products were visualized by ethidium bromide-stained agarose gels (30,32).…”

Section: Methodsmentioning

confidence: 99%

“…Human prostate carcinoma cell lines PC-3 and LNCaP were a gift of dr dan Mercola (The SKCC, La Jolla, CA, USA). The cells were cultured in RPMI-1640 medium supplemented with 100 ml/l fetal bovine serum (FBS), 8x10 5 U/l penicillin and 0.1 g/l streptomycin in humidified incubator containing 50 ml/l CO 2 at 37˚C (30)(31)(32). Tris Borate-EdTA and acrylamide-bisacrylamide (29:1) were obtained from Bio-Rad (Richmond, CA) luciferase assay reagent, lysis buffer and the pGL-2 luciferase vector were obtained from Promega (Madison, WI).…”

Section: Methodsmentioning

confidence: 99%

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Overexpression of EGR-1 modulates the activity of NF-κB and AP-1 in prostate carcinoma PC-3 and LNCaP cell lines

Parra

Ferreira²,

Ortega³

2011

Int J Oncol

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Abstract. To address elements that might uniquely characterize EGR-1 mediated signaling, the expression of two transcription factors, namely, nuclear factor kappa B (NF-κB) and activator protein-1 (AP-1) were studied. PC-3 and LNCaP prostate carcinoma cell lines were transiently transfected with wildtype Egr-1 expression plasmid (pCMV-Egr-1) and treated with cisplatin and TPA. Overexpression of EGR-1 was found to induce nuclear expression of both, NF-κB and AP1. However, the intensity of the induced AP-1 and NF-κB was diminished after cisplatin treatment, but not after TPA. Our findings confirm that the overexpression of wild-type Egr-1 caused a marked increase in cell proliferation in PC-3 and LNCaP proliferation in a 14-day soft agar colony forming assay. In addition, luciferase reporter gene assay showed that the transcriptional activity of AP-1 and NF-κB in PC-3 and LNCaP prostate carcinoma cell lines was also modulated by the overexpression of EGR-1 in these cells using tandem repeated Luc-AP-1 and Luc-NF-κB. The activation of both NF-κB and AP-1 are key steps in the cascade of events following the activation of the EGR-1 gene. It was revealed that overexpression of EGR-1 selectively increased AP-1 and NF-κB activation, and that the activation of these nuclear factors appears to be essential for the induction of proliferation and anchorage independence in activated PC-3 and LNCaP cells. However, the mechanism underlying the modulation of AP-1 and NF-κB by the overexpression of EGR-1 is still unknown.

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“…The effect of siRNA involves post-transcriptional gene silencing via a process in which double stranded RNA (dsRNA) inhibits gene expression in a sequence-dependent manner through degradation of the corresponding mRNA. Its blocking action on gene expression has been successfully observed in rat and human cells cultured in vitro, and the knockdown of genes in cells has been achieved (12)(13)(14)(15). In addition, the development of retroviral constructs in which the polymerase-III H1-RNA gene promoter synthesizes siRNA-like transcripts, allows stable expression of siRNA, thus rendering this technology applicable as gene transfer (16,17).…”

Section: Introductionmentioning

confidence: 98%

Knockdown of the c-Jun-N-terminal kinase expression by siRNA inhibits MCF-7 breast carcinoma cell line growth

Parra

Ferreira²

2010

Oncol Rep

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Abstract.We have examined the effect of two small interference RNA against Jnk-1 and Jnk-2 in the breast cancer cell line MCF-7. The expression of the JNK-1 and JNK-2 is frequently elevated in breast cancer and is a frequent genetic abnormality in this malignancy. For a better understanding of its role in maintaining the malignant phenotype, we used small RNA interference (siRNA) directed against Jnk-1 or Jnk-2. We made control and Jnk-1 and Jnk-2 siRNA using vector plasmid, which was then transfected to reduce its expression in MCF-7 cells. We assessed the effects of JNK-1 or JNK-2 silencing on cell growth by Western blot analysis, soft agar assay, cell proliferation assay, cell viability by MTT assay and caspase assay in vitro. Our data showed that siRNA against Jnk-1 or Jnk-2 markedly and durably reduced its expression in MCF-7 cells by up to 70%, decreased the growth rate of MCF-7 cells, inhibited colony formation in soft agar and significantly reduced cell growth in MCF-7 carcinoma culture cell line. We also found that depletion of JNK-1/2 in this manner promoted apoptosis of MCF-7 cells upon serum withdrawal. In addition, we found that MCF-7 cells did not exhibit any caspase-3 activity. In conclusion, we observed that JNK-1 and JNK-2 have a pivotal function in the development of breast cancer. Our data show that decreasing the JNK-1 or JNK-2 protein level in MCF-7 cells by siRNA could significantly inhibit MCF-7 cell growth in in vitro assay, and imply the therapeutic potential of siRNA on the treatment of breast cancer by targeting overexpression kinases such as JNK-1/2 and might be a potential therapeutic target for human breast cancer.

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The effect of siRNA-Egr-1 and camptothecin on growth and chemosensitivity of breast cancer cell lines

Cited by 23 publications

References 37 publications

Troglitazone induces apoptosis in gastric cancer cells through the NAG-1 pathway

Troglitazone induces apoptosis in gastric cancer cells through the NAG-1 pathway

Overexpression of EGR-1 modulates the activity of NF-κB and AP-1 in prostate carcinoma PC-3 and LNCaP cell lines

Knockdown of the c-Jun-N-terminal kinase expression by siRNA inhibits MCF-7 breast carcinoma cell line growth

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