ABSTRACT
Despite advancement in breast cancer treatment, 30% of patients with early breast cancers experience relapse with distant metastasis. It is a challenge to identify patients at risk for relapse; therefore, the identification of markers and therapeutic targets for metastatic breast cancers is imperative. Here, we identified DP103 as a biomarker and metastasis-driving oncogene in human breast cancers and determined that DP103 elevates matrix metallopeptidase 9 (MMP9) levels, which are associated with metastasis and invasion through activation of NF-κB. In turn, NF-κB signaling positively activated DP103 expression. Furthermore, DP103 enhanced TGF-ß-activated kinase-1 (TAK1) phosphorylation of NF-κB-activating IκB kinase 2 (IKK2), leading to increased NF-κB activity. Reduction of DP103 expression in invasive breast cancer cells reduced phosphorylation of IKK2, abrogated NF-κB-mediated MMP9 expression, and impeded metastasis in a murine xenograft model. In breast cancer patient tissues, elevated levels of DP103 correlated with enhanced MMP9, reduced overall survival, and reduced survival after relapse. Together, these data indicate that a positive DP103/NF-κB feedback loop promotes constitutive NF-κB activation in invasive breast cancers and activation of this pathway is linked to cancer progression and the acquisition of chemotherapy resistance. Furthermore, our results suggest that DP103 has potential as a therapeutic target for breast cancer treatment.
Subject(s)
Breast Neoplasms/pathology , DEAD Box Protein 20/physiology , Breast Neoplasms/mortality , Cell Line, Tumor , Cell Movement , DEAD Box Protein 20/analysis , DEAD Box Protein 20/genetics , Female , Humans , I-kappa B Kinase/metabolism , MAP Kinase Kinase Kinases/physiology , Matrix Metalloproteinase 9/analysis , Matrix Metalloproteinase 9/genetics , NF-kappa B/physiology , Neoplasm Invasiveness , Neoplasm MetastasisABSTRACT
Heparan sulfate 3-O-sulfotransferase 2 (HS3ST2), an enzyme mediating 3-O-sulfation of heparan sulfate (HS), is silenced by hypermethylation in breast cancer. As HS has an important co-receptor function for numerous signal transduction pathways, the phenotypical changes due to HS3ST2 reexpression were investigated in vitro using high and low invasive breast cancer cell lines. Compared to controls, highly invasive HS3ST2-expressing MDA-MB-231 cells showed enhanced Matrigel invasiveness, transendothelial migration and motility. Affymetrix screening and confirmatory real-time PCR and Western blotting analysis revealed increased expression of several matrix metalloproteinases, cadherin-11, E-cadherin and CEACAM-1, while protease inhibitor and annexin A10 expression were decreased. Low invasive HS3ST2 -expressing MCF-7 cells became even less invasive, with no change in gelatinolytic MMP activity. HS3ST2 expression increased HS-dependent basal and FGF2-specific signaling through the constitutively active p44/42 MAPK pathway in MDA-MB-231 cells. Increased MAPK activation was accompanied by upregulation of ß-catenin in MDA-MB-231, and of the transcription factor Tcf4 in both cell lines. Dysregulation of Tcf4-regulated ion transporters and increased cytosolic acidification were observed in HS3ST2-expressing MDA-MB-231 cells, which is a possible underlying cause of increased chemosensitivity towards doxorubicine and paclitaxel in these cells. This study provides the first in vitro evidence of the involvement of HS3ST2 in breast cancer cell invasion and chemosensitivity.
Subject(s)
Basic Helix-Loop-Helix Leucine Zipper Transcription Factors/metabolism , Breast Neoplasms/metabolism , Breast Neoplasms/pathology , Cadherins/metabolism , Mitogen-Activated Protein Kinases/metabolism , Sulfotransferases/metabolism , Transcription Factor 7-Like 2 Protein/metabolism , Transcription Factors/metabolism , Antineoplastic Agents/pharmacology , Basic Helix-Loop-Helix Leucine Zipper Transcription Factors/genetics , Blotting, Western , Breast Neoplasms/drug therapy , Cadherins/genetics , Cell Adhesion/drug effects , Cell Movement/drug effects , Cell Proliferation/drug effects , Endothelium, Vascular/cytology , Endothelium, Vascular/drug effects , Endothelium, Vascular/metabolism , Female , Glycosaminoglycans/metabolism , Humans , Immunoenzyme Techniques , Microscopy, Fluorescence , Mitogen-Activated Protein Kinases/genetics , Neoplasm Invasiveness , Phosphorylation , RNA, Messenger/genetics , Real-Time Polymerase Chain Reaction , Reverse Transcriptase Polymerase Chain Reaction , Signal Transduction , Sulfotransferases/genetics , Transcription Factor 4 , Transcription Factor 7-Like 2 Protein/genetics , Transcription Factors/genetics , Tumor Cells, Cultured , beta Catenin/genetics , beta Catenin/metabolismABSTRACT
Breast carcinoma is one of the leading causes of mortality among female cancers globally. Heparan sulfate proteoglycans, found predominantly on cell surfaces and in the extracellular matrix, are known to regulate breast cancer cellular behavior. Many studies have shown that these molecules serve as potential biomarkers for breast cancer. In addition, they have aberrant expression patterns and participate in various molecular signaling pathways in tumor progression. There is substantial interest in targeting heparan sulfate proteoglycans for cancer treatment, which needs to be tailored according to the roles that each proteoglycan plays in cancer biology. Current clinical trials using phosphomannopentaose sulfate, a heparan sulfate mimic, and various forms of heparin have produced promising results in breast cancer patients. Besides heparan sulfate chains, novel therapeutic agents could potentially be developed to regulate the proteoglycan core proteins as well as enzymes that modify heparan sulfation patterns. This review discusses the current use and future prospective applications of heparan sulfate proteoglycans, which have been recently patented, as therapeutic targets in breast cancer treatment.
