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(E)-3-(3,5-dimethoxyphenyl)-1-(2-methoxyphenyl)prop-2-en-1-one (DPP23) is a synthetic polyphenol derivative that selectively induces apoptosis in cancer cells through the unfolded protein response pathway. In the present study, we evaluated the effect of DPP23 on tumour invasion and metastasis. Here, we show that DPP23 inhibited tumour necrosis factor alpha (TNFα)-induced motility, F-actin formation, and the invasive capability of MDA-MB-231 cells. DPP23 inhibited NF-κB-dependent MMP-9 expression at the transcriptional level. Akt is involved in the activation of IKK, an upstream regulator of NF-κB. DPP23 inhibited IKK and Akt, and knockdown of Akt2 significantly inhibited TNFα-induced IKK phosphorylation. We found that DPP23 bound to the catalytic domain of Akt2, as revealed by an in silico molecular docking analysis. These results suggest that DPP23 prevents TNFα-induced invasion of highly metastatic MDA-MB-231 breast cancer cells by inhibiting Akt–IKK–NF-κB axis-mediated MMP-9 gene expression. In addition, DPP23 attenuated experimental liver metastasis in a syngenic intrasplenic transplantation model using 4T1 mouse mammary carcinoma cells. Collectively, these results suggest that DPP23 could be used as a potential platform for the prevention of invasion and metastasis of early-stage breast cancer or as an adjuvant for chemo/radiotherapy.

Cyclin-dependent kinase inhibitor (CDKN1A), often referred to as p21Waf1/Cip1 (p21), is induced by a variety of environmental stresses. Transcription factor ELK-1 is a member of the ETS oncogene superfamily. Here, we show that ELK-1 directly transactivates the p21 gene, independently of p53 and EGR-1, in sodium arsenite (NaASO 2 )-exposed HaCaT cells. Promoter deletion analysis and site-directed mutagenesis identified the presence of an ELK-1-binding core motif between ؊190 and ؊170 bp of the p21 promoter that confers inducibility by NaASO 2 . Chromatin immunoprecipitation and electrophoretic mobility shift analyses confirmed the specific binding of ELK-1 to its putative binding sequence within the p21 promoter. In addition, NaASO 2 -induced p21 promoter activity was enhanced by exogenous expression of ELK-1 and reduced by expression of siRNA targeted to ELK-1 mRNA. The importance of ELK-1 in response to NaASO 2 was further confirmed by the observation that stable expression of ELK-1 siRNA in HaCaT cells resulted in the attenuation of NaASO 2 -induced p21 expression. Although ELK-1 was activated by ERK, JNK, and p38 MAPK in response to NaASO 2 , ELK-1-mediated activation of the p21 promoter was largely dependent on ERK. In addition, EGR-1 induced by ELK-1 seemed to be involved in NaASO 2 -induced expression of BAX. This supports the view that the ERK/ELK-1 cascade is involved in p53-independent induction of p21 and BAX gene expression.

BackgroundBreast cancer is the most common type of malignancy in women worldwide. Euphorbia humifusa Willd (EuH) is a plant that is widely used as a traditional medicine. However, no systemic studies on the anti-cancer effects of EuH have been reported. The aim of this study is to evaluate the anti-metastatic effect of the EuH.MethodsEthyl acetate fraction was prepared from EuH methanol extracts (EA/EuH). Inhibitory effect of EA/EuH on cell migration was determined using an in vitro scratch-wound healing assay. The anti-invasive activity was determined by in vitro three-dimensional spheroid culture system and in vivo syngenic experimental lung metastasis experiment. Gene expression profiles were analyzed by using RT-PCR, real-time PCR, and luciferase reporter assay systems.ResultsEthyl acetate fraction from the EuH extract (EA/EuH) inhibited the migration and invasive capabilities of highly metastatic MDA-MB-231 breast cancer cells and attenuated syngeneic lung metastasis of mouse 4 T1 breast cancer cells in vivo. Mechanistically, EA/EuH decreased tumor necrosis factor alpha (TNFα)-induced matrix metalloproteinase (MMP)-9 mRNA expression through the inhibition of NF-κB activity in MDA-MB-231 cells.ConclusionEuH may be beneficial in the prevention of invasion and metastasis of early stage breast cancer and can be served as an anti-metastatic agent or adjuvant therapy against metastatic breast cancer.

The breast cancer susceptibility gene BRCA1 encodes a nuclear protein, which functions as a tumor suppressor and is involved in gene transcription and DNA repair processes. Many families with inherited breast and ovarian cancers have mutations in the BRCA1 gene. However, only a few studies have reported on the mechanism underlying the regulation of BRCA1 expression in humans. In this study, we investigated the transcriptional regulation of BRCA1 in HeLa cells treated with etoposide. We found that three Egr-1-binding sequences (EBSs) were located at −1031, −1005, and −385 within the enhancer region of the BRCA1 gene. Forced expression of Egr-1 stimulated the BRCA1 promoter activity. EMSA data showed that Egr-1 bound directly to the EBS within the BRCA1 gene. Knockdown of Egr-1 through the expression of a small hairpin RNA (shRNA) attenuated etoposide-induced BRCA1 promoter activity. We conclude that Egr-1 targets the BRCA1 gene in HeLa cells exposed to etoposide. [BMB Reports 2013; 46(2): 92-96]