ABSTRACT
Several different cytokines and growth factors secreted by mesenchymal stem cells (MSCs) have been hypothesized to play a role in breast cancer progression. By using a small panel of breast cancer cell lines (MCF-7, T47D, and SK-Br-3 cells), we analyzed the role of interleukin-6 (IL-6) and vascular endothelial growth factor A (VEGF) in the cross-talk between MSCs and breast cancer cells. We performed migration assays in which breast cancer cells were allowed to migrate in response to conditioned medium from MSCs (MSCs-CM), in absence or in presence of the anti-VEGF antibody bevacizumab or an anti-IL-6 antibody, alone or in combination. We found that anti-VEGF and anti-IL-6 antibodies inhibited the migration of breast cancer cells and that the combination had an higher inhibitory effect. We next evaluated the effects of recombinant VEGF and IL-6 proteins on breast cancer cell growth and migration. IL-6 and VEGF had not significant effects on the proliferation of breast carcinoma cells. In contrast, both VEGF and IL-6 significantly increased the ability to migrate of MCF-7, T47D and SK-Br-3 cells, with the combination showing a greater effect as compared with treatment with a single protein. The combination of VEGF and IL-6 produced in breast cancer cells a more significant and more persistent activation of MAPK, AKT, and p38MAPK intracellular signaling pathways. These results suggest that MSC-secreted IL-6 and VEGF may act as paracrine factors to sustain breast cancer cell migration.
Subject(s)
Breast Neoplasms/genetics , Interleukin-6/metabolism , Mesenchymal Stem Cells/metabolism , Vascular Endothelial Growth Factor A/metabolism , Angiogenesis Inhibitors/pharmacology , Antibodies, Monoclonal, Humanized/pharmacology , Antibodies, Neutralizing/pharmacology , Bevacizumab , Breast Neoplasms/metabolism , Breast Neoplasms/pathology , Cell Communication , Cell Movement/drug effects , Culture Media, Conditioned/pharmacology , Drug Synergism , Gene Expression Regulation, Neoplastic/drug effects , Humans , Interleukin-6/antagonists & inhibitors , Interleukin-6/pharmacology , Mesenchymal Stem Cells/pathology , Mitogen-Activated Protein Kinases/genetics , Mitogen-Activated Protein Kinases/metabolism , Proto-Oncogene Proteins c-akt/genetics , Proto-Oncogene Proteins c-akt/metabolism , Recombinant Proteins/antagonists & inhibitors , Recombinant Proteins/metabolism , Recombinant Proteins/pharmacology , Signal Transduction/drug effects , Tumor Cells, Cultured , Vascular Endothelial Growth Factor A/antagonists & inhibitors , Vascular Endothelial Growth Factor A/pharmacology , p38 Mitogen-Activated Protein Kinases/genetics , p38 Mitogen-Activated Protein Kinases/metabolismABSTRACT
INTRODUCTION: Increased bone resorption is associated with several diseases, including osteoporosis, bone metastases and Paget's disease of bone. Zoledronic acid (ZA) is the most potent of the clinically available bisphosphonates. In addition to its antiresorptive activity, there has been increasing evidence to suggest that it also has anticancer properties. AREAS COVERED: This article is complied through PubMed and Medline databases searches on ZA. In this review, the authors summarize the current knowledge (up to December 2010) on the pharmacodynamic and pharmacokinetic properties of ZA. EXPERT OPINION: ZA is a well-tolerated and effective drug in the management of metabolic as well as cancer-related bone disease. Clinical benefits in cancer patients include improvement in bone pain, reduction in skeletal events and delay of time to first skeletal event. However, novel indications for this drug are emerging from clinical studies in early breast cancer. Recent findings suggest that the addition of ZA to endocrine therapy can significantly prevent bone loss in premenopausal patients. Increasing evidence also indicates a potential anticancer activity of ZA, although this property needs to be further explored.
Subject(s)
Antineoplastic Agents/pharmacokinetics , Bone Density Conservation Agents/pharmacokinetics , Bone Diseases/drug therapy , Bone Neoplasms/drug therapy , Chemotherapy, Adjuvant/methods , Diphosphonates/pharmacokinetics , Imidazoles/pharmacokinetics , Adjuvants, Pharmaceutic/pharmacokinetics , Bone Diseases/chemically induced , Bone Neoplasms/secondary , Breast Neoplasms/drug therapy , Clinical Trials as Topic , Drug Evaluation , Female , Humans , Osteoporosis/drug therapy , Zoledronic AcidABSTRACT
Increasing evidence suggests that bone marrow-derived mesenchymal stem cells (MSCs) are recruited into the stroma of developing tumors where they contribute to cancer progression. MSCs produce different growth factors that sustain tumor-associated neo-angiogenesis. Since the majority of carcinomas secrete ligands of the epidermal growth factor receptor (EGFR), we assessed the role of EGFR signaling in regulating the release of angiogenic factors in MSCs. Treatment of human primary MSCs and of the human osteoblastic cell line hFOB with transforming growth factor α (TGF-α), one of the main ligands of the EGFR, significantly induced activation of this receptor and of different intracellular signaling proteins, including the PI3K/AKT and the MEK/MAPK pathways. TGF-α induced a significant increase in the levels of secretion of vascular endothelial growth factor in both MSCs and hFOB. Conditioned medium from TGF-α treated MSCs showed an higher in vivo angiogenic effect as compared with medium from untreated cells. Treatment of MSCs with TGF-α also produced a significant increase in the secretion of other angiogenic growth factors such as angiopoietin-2, granulocyte-colony stimulating factor, hepatocyte growth factor, interleukin (IL)-6, IL-8, and platelet-derived growth factor-BB. Using selective MEK and PI3K inhibitors, we found that both MEK/MAPK and the PI3K/AKT signaling pathways mediate the ability of TGF-α to induce secretion of angiogenic factors in MSCs. Finally, stimulation with TGF-α increased the ability of MSCs to induce migration of MCF-7 breast cancer cells. These data suggest that EGFR signaling regulates the ability of MSCs to sustain cancer progression through the release of growth factors that promote neo-angiogenesis and tumor cell migration.
Subject(s)
Angiogenic Proteins/metabolism , ErbB Receptors/metabolism , Mesenchymal Stem Cells/metabolism , Adenocarcinoma/drug therapy , Adenocarcinoma/metabolism , Breast Neoplasms/drug therapy , Breast Neoplasms/metabolism , Cell Line , Cell Line, Tumor , Cell Movement/drug effects , Female , Humans , Ligands , Mesenchymal Stem Cells/drug effects , Metabolic Networks and Pathways/drug effects , Neovascularization, Pathologic/drug therapy , Neovascularization, Pathologic/metabolism , Osteoblasts/drug effects , Osteoblasts/metabolism , Protein Kinase Inhibitors/pharmacology , Transforming Growth Factor alpha/pharmacologyABSTRACT
Bisphosphonates (BPs) are cornerstones in the treatment of patients with compromised skeletal integrity (either cancer related or not). However, a major indication for BPs use remains the treatment of patients with advanced cancer metastatic to the bone. Recently, several observations derived from clinical trials, primarily aimed at establishing the impact of BPs on the bone health of cancer patients, suggested a potential role for these agents as direct anti-tumor drugs. Consequently, a series of preclinical works were produced with the aim of clarifying the mechanism underlying this observed effect. However, the impact of such data is still under debate owing to the intrinsic weakness of observations from trials not adequately powered to support them. In conclusion, the entire matter remains one of the most intriguing in oncology, and data from ongoing and planned future studies will surely provide us with more information on the great potential of BPs in the adjuvant setting.
Subject(s)
Antineoplastic Agents/pharmacology , Breast Neoplasms/prevention & control , Diphosphonates/pharmacology , Neoplasms/drug therapy , Animals , Antineoplastic Agents/adverse effects , Antineoplastic Agents/chemistry , Antineoplastic Agents/therapeutic use , Chemotherapy, Adjuvant , Clinical Trials as Topic , Diphosphonates/adverse effects , Diphosphonates/chemistry , Diphosphonates/therapeutic use , Drug Evaluation, Preclinical , Female , Humans , Male , Molecular StructureABSTRACT
Treatment of breast cancer cells with a combination of the EGFR-tyrosine kinase inhibitor (EGFR-TKI) gefitinib and the anti-ErbB-2 monoclonal antibody trastuzumab results in a synergistic antitumor effect. In this study, we addressed the mechanisms involved in this phenomenon. The activation of signaling pathways and the expression of cell cycle regulatory proteins were studied in SK-Br-3 and BT-474 breast cancer cells, following treatment with EGFR and/or ErbB-2 inhibitors. Treatment with the gefitinib/trastuzumab combination produced, as compared with a single agent, a more prolonged blockade of AKT and MAPK activation, a more pronounced accumulation of cells in the G0/G1 phase of the cell cycle, a more significant increase in the levels of p27(kip1) and of hypophosphorylated pRb2, and a decrease in the levels of Cyclin D1 and survivin. Similar findings were observed with the EGFR/ErbB-2 inhibitor lapatinib. Gefitinib, trastuzumab, and their combination increased the stability of p27(kip1), with the combination showing the highest effects. Blockade of both receptors with gefitinib/trastuzumab or lapatinib induced a significant increase in the levels of p27(kip1) mRNA and in the nuclear levels of the p27(kip1) transcription factor FKHRL-1. Inhibition of PI3K signaling also produced a significant raise in p27(kip1) mRNA. Finally, down-modulation of FKHRL-1 with siRNAs prevented the lapatinib-induced increase of p27(kip1) mRNA. The synergism deriving from EGFR and ErbB-2 blockade is mediated by several different alterations in the activation of signaling proteins and in the expression of cell cycle regulatory proteins, including transcriptional and posttranscriptional regulation of p27(kip1) expression.
Subject(s)
Antineoplastic Combined Chemotherapy Protocols/pharmacology , Breast Neoplasms/enzymology , Cell Cycle Proteins/metabolism , Cell Cycle/drug effects , ErbB Receptors/antagonists & inhibitors , Receptor, ErbB-2/antagonists & inhibitors , Signal Transduction/drug effects , Antibodies, Monoclonal/pharmacology , Antibodies, Monoclonal, Humanized , Breast Neoplasms/genetics , Breast Neoplasms/pathology , Cell Line, Tumor , Cyclin-Dependent Kinase Inhibitor p27 , Drug Synergism , ErbB Receptors/metabolism , Female , Forkhead Box Protein O3 , Forkhead Transcription Factors/metabolism , Gefitinib , Humans , Intracellular Signaling Peptides and Proteins/genetics , Intracellular Signaling Peptides and Proteins/metabolism , Lapatinib , Mitogen-Activated Protein Kinases/metabolism , Phosphorylation , Protein Kinase Inhibitors/pharmacology , Proto-Oncogene Proteins c-akt/metabolism , Quinazolines/pharmacology , RNA Interference , RNA, Messenger/genetics , RNA, Messenger/metabolism , Receptor, ErbB-2/metabolism , Retinoblastoma-Like Protein p130/metabolism , Time Factors , TrastuzumabABSTRACT
Analysis by DNA microarrays has led to the identification of molecular subtypes of breast carcinomas that show a distinct expression profile. Several studies have demonstrated that this 'intrinsic subtype' classification has a strong prognostic value. In addition, gene expression profiling techniques have been used to identify gene signatures that could be associated with the outcome of breast cancer patients. Several different genomic tests have been shown to better define the prognosis of early-stage breast cancer patients as compared with conventional clinical and pathological characteristics of the tumors, and some assays are already commercially available. However, it must be emphasized that the prognostic power of these genetic classifiers has not been confirmed yet in prospective trials. Genetic signatures that might predict the activity of specific chemotherapy agents have also been developed by using gene expression profiling techniques. The same approach has been used to identify gene signatures associated with the activation of oncogenic pathways that might represent targets for molecular therapy of breast cancer. By using these approaches, gene expression techniques might significantly improve our ability to predict the risk of recurrence and to tailor the treatment for each individual breast cancer patient.
