Hyereen Kang

Celastrol inhibits breast cancer cell invasion via suppression of NF-ĸB-mediated matrix metalloproteinase-9 expression.

Background/Aims: Metastasis is one of the main causes of death for patients with malignant tumors. Induction of matrix metalloproteinase (MMP)-9 is particularly important for the invasiveness of various cancer cells. Celastrol, a triterpenoid isolated from the traditional Chinese medicine, is known to inhibit the proliferation of a variety of tumor cells, including leukemia, glioma, prostate and breast cancer cells. In this study, we investigated the effect of celastrol on the migration and invasion of human breast carcinoma cells. Results: We observed that celastrol suppressed phorbol 12-myristate 13-acetate (PMA)-induced invasion and migration of MCF-7 cells. We also found that celastrol inhibited PMA-induced MMP-9 expression at both the mRNA and the protein levels, and the proteolytic activity of MMP-9 in MCF-7 cells. Our results revealed that celastrol inhibited the transcriptional activity of MMP-9 by suppression of the DNA binding activity of NF-ĸB in the MMP-9 promoter, and inhibited degradation of IĸBα and nuclear translocation of NF-ĸB. Conclusion: These results indicate that celastrol inhibits NF-ĸB-mediated MMP-9 expression, resulting in suppression of breast cancer cell invasion and migration that is induced by PMA. Celastrol is a potential agent for clinical use in preventing the invasion and metastasis of human malignant breast tumors.

The role of annexin A1 in expression of matrix metalloproteinase-9 and invasion of breast cancer cells.

Matrix metalloproteinase-9 (MMP-9) plays an important role in the invasion and metastasis of cancer cells. However, the regulatory mechanism of MMP-9 expression and its biological effects on breast cancer development remain obscure. In the current study, we examined the potential role of annexin A1 (ANXA1) in regulating migration and invasion in breast cancer cell lines. Both ANXA1 mRNA and protein are expressed in the highly invasive, hormone-insensitive human breast cancer cell lines MDA-MB-231 and SKBr3, but not in the hormone-responsive cell lines MCF-7 and T47D. Downregulation of ANXA1 expression with specific small interfering RNAs (ANXA1 siRNA) in MDA-MB-231 cells resulted in decreased cancer cell migration and invasion. Ablation of ANXA1 expression decreases the expression of MMP-9 at both the mRNA and protein levels and also reduces the proteolytic activity of MMP-9 in MDA-MB-231 cells. Moreover, silencing ANXA1 also decreases the transcriptional activity of MMP-9 by the suppression of nuclear factor kappa-B (NF-κB) activity. Collectively, these results indicate that ANXA1 functions as a positive regulator of MMP-9 expression and invasion of breast cancer cells through specific activation of the NF-κB signaling pathway.

Celastrol inhibits TGF-β1-induced epithelial-mesenchymal transition by inhibiting Snail and regulating E-cadherin expression.

The epithelial-mesenchymal transition (EMT) is a pivotal event in the invasive and metastatic potentials of cancer progression. Celastrol inhibits the proliferation of a variety of tumor cells including leukemia, glioma, prostate, and breast cancer; however, the possible role of celastrol in the EMT is unclear. We investigated the effect of celastrol on the EMT. Transforming growth factor-beta 1 (TGF-β1) induced EMT-like morphologic changes and upregulation of Snail expression. The downregulation of E-cadherin expression and upregulation of Snail in Madin-Darby Canine Kidney (MDCK) and A549 cell lines show that TGF-β1-mediated the EMT in epithelial cells; however, celastrol markedly inhibited TGF-β1-induced morphologic changes, Snail upregulation, and E-cadherin expression. Migration and invasion assays revealed that celastrol completely inhibited TGF-β1-mediated cellular migration in both cell lines. These findings indicate that celastrol downregulates Snail expression, thereby inhibiting TGF-β1-induced EMT in MDCK and A549 cells. Thus, our findings provide new evidence that celastrol suppresses lung cancer invasion and migration by inhibiting TGF-β1-induced EMT.

N‐(4‐hydroxyphenyl)retinamide inhibits breast cancer cell invasion through suppressing NF‐KB activation and inhibiting matrix metalloproteinase‐9 expression

Synthetic retinoid N‐(4‐hydroxyphenyl)retinamide (4‐HPR) has been reported to exhibit anti‐invasive and anti‐metastatic activities by suppressing the enzymatic activity of matrix metalloproteinase (MMP)‐9, but the underlying mechanism remains unclear. Here, we show that 4‐HPR blocks the activity of MMP‐9 in two ways: by reducing phorbol 12‐myristate 13‐acetate (PMA)‐induced MMP‐9 secretion and by suppressing cell invasion through the downregulation of MMP‐9 gene transcription in MCF‐7 breast cancer cells. 4‐HPR inhibits the transcriptional activity of MMP‐9 by reducing the DNA‐binding activity of NF‐κB on the MMP‐9 promoter as well as by inhibiting the degradation of IκBα, leading to cytoplasmic accumulation of NF‐κB. We also found that 4‐HPR inhibits invasion and MMP‐9 expression in the highly metastatic breast cancer cell line MDA‐MB‐231. Thus, 4‐HPR might be a potent anti‐invasive agent that works by suppressing MMP‐9 expression via the NF‐κB signaling pathway. J. Cell. Biochem. 113: 2845–2855, 2012.

Human Leucine Zipper Protein sLZIP Induces Migration and Invasion of Cervical Cancer Cells via Expression of Matrix Metalloproteinase-9

Background: Proteolytic degradation of the extracellular matrix and basement membranes by matrix metalloproteinases (MMPs) is crucial in tumor invasion and metastasis. Results: sLZIP induces the expression of MMP-9, leading to enhancement of migration and invasion of cervical cancer cells. Conclusion: A novel regulatory mechanism of MMP-9 expression is characterized. Significance: sLZIP is a potential target for preventing the invasion and metastasis of cervical cancer. Extracellular proteolysis mediates tissue homeostasis. In cancer, altered proteolysis leads to abnormal tumor growth, inflammation, tissue invasion, and metastasis. Matrix metalloproteinase-9 (MMP-9) represents one of the most prominent proteinases associated with inflammation and tumorigenesis. The recently identified human transcription factor sLZIP is a member of the leucine zipper transcription factor family. Although sLZIP is known to function in ligand-induced transactivation of the glucocorticoid receptor, its exact functions and target genes are not known. In this study, we investigated the role of sLZIP in MMP-9 expression and its involvement in cervical cancer development. Our results show that sLZIP increased the expression of MMP-9 at both the mRNA and protein levels and the proteolytic activity of MMP-9 in HeLa and SiHa cells. sLZIP also increased the transcriptional activity of MMP-9 by binding directly to the cAMP-responsive element of the MMP-9 promoter region. Involvement of sLZIP in MMP-9 expression was further supported by the fact that ME-180 cells expressing sLZIP siRNA were refractory to MMP-9 expression. Results from wound healing and invasion assays showed that sLZIP enhanced both the migration and invasion of cervical cancer cells. The increased migration and invasion of HeLa and SiHa cells that were induced by sLZIP were abrogated by inhibition of the proteolytic activity of MMP-9. These results indicate that sLZIP plays a critical role in MMP-9 expression and is probably involved in invasion and metastasis of cervical cancer.

Inhibitory effect of Trolox on the migration and invasion of human lung and cervical cancer cells.

The antioxidant 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox) is implicated in migration and invasion of metastatic tumors. However, the molecular mechanism underlying the effect of Trolox on metastatic cancer cells is not known. We found that a non-cytotoxic dose of Trolox decreased phorbol 12-myristate 13-acetate (PMA)-induced invasion and migration of both A549 and HeLa cancer cells. We also found that Trolox suppressed both the expression and the proteolytic activity of matrix metalloproteinase-9 (MMP-9), and that the promoter activity of PMA-induced MMP-9 was inhibited by Trolox. Our results show that Trolox inhibits the transcriptional activity of MMP-9 by suppression of NF-κB transactivation. These results indicate that Trolox inhibits NF-κB-mediated MMP-9 expression, leading to the suppression of migration and invasion in lung and cervical cancer cells. Trolox is a potential agent for clinical use in preventing the invasion and metastasis of human malignant lung and cervical cancers.

Glaucine inhibits breast cancer cell migration and invasion by inhibiting MMP-9 gene expression through the suppression of NF-κB activation

Abstract Matrix metalloproteinase-9 (MMP-9) plays a central role in the invasion and metastasis of various types of cancer cells. Here, we demonstrate that glaucine, an alkaloid isolated from the plant Corydalis turtschaninovii tuber (Papaveraceae), can inhibit the migration and invasion of human breast cancer cells. We further show that glaucine significantly blocks phorbol 12-myristate 13-acetate (PMA)-induced MMP-9 expression and activity in a dose-dependent manner. Results from reporter gene and electrophoretic mobility shift assays revealed that glaucine inhibits MMP-9 expression by suppressing activation of the nuclear transcription factor nuclear factor-κB (NF-κB). Moreover, glaucine attenuates PMA-induced IκBα degradation and nuclear translocation of NF-κB. Finally, we also found that glaucine inhibits invasion and MMP-9 expression in the highly metastatic MDA-MB-231 breast cancer cell line. Taken together, our findings indicate that the MMP-9 inhibitory activity of glaucine and its abilities to attenuate IκBα and NF-κB activities may be therapeutically useful as a novel means of controlling breast cancer growth and invasiveness.

Human LZIP induces monocyte CC chemokine receptor 2 expression leading to enhancement of monocyte chemoattractant protein 1/CCL2-induced cell migration

Chemokines and chemokine receptors play a role in migration of circulating leukocytes to the region of inflammation. Human LZIP is an uncharacterized transcription factor and is known to participate in leukotactin (Lkn)-1/CCL15-induced cell migration. We investigated the role of human LZIP in expression of CC chemokine receptors (CCRs) and its involvement in monocyte migration. RNase protection analysis showed that LZIP increased mRNA expression of CCR2 and CCR1 in THP-1 cells. Surface expressions of both CCR2 and CCR1 were also increased by LZIP. Results from an electrophoretic mobility shift assay showed that LZIP binds to the C/EBP element in the CCR2 promoter. LZIP also enhanced the chemotactic activities of monocyte chemoattractant protein-1/CCL2 and Lkn-1. These results suggest that LZIP regulates expression of chemokine receptors that are involved in monocyte migration.

CoCl2 induces PC12 cells apoptosis through p53 stability and regulating UNC5B.

The receptor uncoordinated 5B (UNC5B) induces apoptosis in the absence of its cognate ligand netrin-1. However, the role of UNC5B in hypoxia-induced apoptosis is not known. Here, we have demonstrated the biological functions of UNC5B in hypoxia-induced apoptosis and related regulatory pathways and examined the effects of UNC5B on p53-dependent apoptosis in PC12 cells under hypoxic conditions. First, we characterized p53-dependent PC12 cell death induced by CoCl2. Our data showed that CoCl2 increased p53 stabilization and transcriptional activity. The downregulation of p53 expression with specific small interfering RNA (p53 siRNA) in CoCl2-treated PC12 cells caused reduction in apoptosis, UNC5B expression, and p21 expression. Moreover, in PC12 cells, ectopic expression of UNC5B significantly enhanced apoptosis, while silencing of UNC5B with siRNA significantly inhibited apoptosis. In addition, netrin-1 significantly inhibited CoCl2-induced p53 stability and UNC5B expression and CoCl2-induced caspase-3 activity and cell death. Collectively, these results demonstrate a novel role for p53 in the control of CoCl2-induced apoptosis through the regulation of UNC5B.

The Role of sLZIP in Transcriptional Regulation of c-Jun and Involvement in Migration and Invasion of Cervical Cancer Cells

Background/Aims: Matrix metalloproteinase-9 (MMP-9) plays an important role in tumor invasion and metastasis through the breakdown of extracellular matrix. The c-Jun protein, a major component of the AP-1 transcription factor, is elevated in various cancers. Small leucine zipper protein (sLZIP) is a member of the leucine zipper transcription factor family. Although sLZIP is known to be involved in cancer cell migration and invasion, its biological roles in cancer development and the cellular target genes are not fully understood. In this study, we investigated the role of sLZIP in c-Jun expression, and their effects on expression of MMP-9 and migration of cervical cancer cells. Methods and Results: sLZIP up-regulates transcription of c-Jun by binding directly to the CRE region in the c-Jun promoter. Elevated c-Jun due to sLZIP leads to activation of MMP-9 transcription by interaction with the AP-1 binding site in the MMP-9 promoter. c-Jun siRNA repressed migration and invasion of cervical cancer cells, whereas sLZIP recovered migration and invasion of cells transfected with c-Jun siRNA. Immunohistochemical analysis results revealed a significant correlation between the expressions of sLZIP and MMP-9 in clinical cervical specimens. Conclusion: These results indicate that sLZIP plays a role in expression of c-Jun, and migration and invasion of cervical cancer cells via regulation of MMP-9 transcription.