New use of an old drug: inhibition of breast cancer stem cells by benztropine mesylate

Preclinical and Clinical Trials of New Treatment Strategies Targeting Cancer Stem Cells in Subtypes of Breast Cancer

Breast cancer (BC) can be classified into various histological subtypes, each associated with different prognoses and treatment options, including surgery, radiation, chemotherapy, and endocrine therapy. Despite advances in this area, many patients still face treatment failure, the risk of metastasis, and disease recurrence, which can ultimately lead to death. Mammary tumors, like other solid tumors, contain a population of small cells known as cancer stem-like cells (CSCs) that have high tumorigenic potential and are involved in cancer initiation, progression, metastasis, tumor recurrence, and resistance to therapy. Therefore, designing therapies specifically targeting at CSCs could help to control the growth of this cell population, leading to increased survival rates for BC patients. In this review, we discuss the characteristics of CSCs, their surface biomarkers, and the active signaling pathways associated with the acquisition of stemness in BC. We also cover preclinical and clinical studies that focus on evaluating new therapy systems targeted at CSCs in BC through various combinations of treatments, targeted delivery systems, and potential new drugs that inhibit the properties that allow these cells to survive and proliferate.

MLL3 loss drives metastasis by promoting a hybrid epithelial-mesenchymal transition state

Phenotypic plasticity associated with the hybrid epithelial-mesenchymal transition (EMT) is crucial to metastatic seeding and outgrowth. However, the mechanisms governing the hybrid EMT state remain poorly defined. Here we showed that deletion of the epigenetic regulator MLL3, a tumour suppressor frequently altered in human cancer, promoted the acquisition of hybrid EMT in breast cancer cells. Distinct from other EMT regulators that mediate only unidirectional changes, MLL3 loss enhanced responses to stimuli inducing EMT and mesenchymal-epithelial transition in epithelial and mesenchymal cells, respectively. Consequently, MLL3 loss greatly increased metastasis by enhancing metastatic colonization. Mechanistically, MLL3 loss led to increased IFNγ signalling, which contributed to the induction of hybrid EMT cells and enhanced metastatic capacity. Furthermore, BET inhibition effectively suppressed the growth of MLL3-mutant primary tumours and metastases. These results uncovered MLL3 mutation as a key driver of hybrid EMT and metastasis in breast cancer that could be targeted therapeutically.

A Platform for Integrating and Sharing Cancer Stem Cell Data

Advancements in cancer research and treatment have highlighted the need for standardization and sharing of cancer stem cell (CSC) data to facilitate research transparency and to promote collaboration within the scientific community. Although previous applications have attempted to gather and disseminate these data, currently no platform organizes the heterogeneous CSC information into a harmonized project-based framework. The aim of our platform, ReMeDy, is to provide an intelligent informatics solution integrating diverse CSC characteristics, outcomes information, and omics data across clinical, preclinical and in vitro studies. These heterogeneous data streams are organized within a multi-modular framework, subjected to a stringent validation by using standardized ontologies, and stored in a searchable format. To test usefulness of our approach for capturing diverse data related to CSCs, we integrated data from 52 publicly-available CSC projects. We validated the robustness of the platform, by efficiently organizing diverse data elements, and demonstrated its potential for promoting future knowledge discovery driven by aggregation of published data. Next steps include expanding number of uploaded CSC projects and developing additional data visualization tools. The platform is accessible through https://remedy.mssm.edu/.

DTI-HeNE: a novel method for drug-target interaction prediction based on heterogeneous network embedding

BACKGROUND

Prediction of the drug-target interaction (DTI) is a critical step in the drug repurposing process, which can effectively reduce the following workload for experimental verification of potential drugs' properties. In recent studies, many machine-learning-based methods have been proposed to discover unknown interactions between drugs and protein targets. A recent trend is to use graph-based machine learning, e.g., graph embedding to extract features from drug-target networks and then predict new drug-target interactions. However, most of the graph embedding methods are not specifically designed for DTI predictions; thus, it is difficult for these methods to fully utilize the heterogeneous information of drugs and targets (e.g., the respective vertex features of drugs and targets and path-based interactive features between drugs and targets).

RESULTS

We propose a DTI prediction method DTI-HeNE (DTI based on Heterogeneous Network Embedding), which is specifically designed to cope with the bipartite DTI relations for generating high-quality embeddings of drug-target pairs. This method splits a heterogeneous DTI network into a bipartite DTI network, multiple drug homogeneous networks and target homogeneous networks, and extracts features from these sub-networks separately to better utilize the characteristics of bipartite DTI relations as well as the auxiliary similarity information related to drugs and targets. The features extracted from each sub-network are integrated using pathway information between these sub-networks to acquire new features, i.e., embedding vectors of drug-target pairs. Finally, these features are fed into a random forest (RF) model to predict novel DTIs.

CONCLUSIONS

Our experimental results show that, the proposed DTI network embedding method can learn higher-quality features of heterogeneous drug-target interaction networks for novel DTIs discovery.

The Breast Cancer Stem Cells Traits and Drug Resistance

Drug resistance is a major challenge in breast cancer (BC) treatment at present. Accumulating studies indicate that breast cancer stem cells (BCSCs) are responsible for the BC drugs resistance, causing relapse and metastasis in BC patients. Thus, BCSCs elimination could reverse drug resistance and improve drug efficacy to benefit BC patients. Consequently, mastering the knowledge on the proliferation, resistance mechanisms, and separation of BCSCs in BC therapy is extremely helpful for BCSCs-targeted therapeutic strategies. Herein, we summarize the principal BCSCs surface markers and signaling pathways, and list the BCSCs-related drug resistance mechanisms in chemotherapy (CT), endocrine therapy (ET), and targeted therapy (TT), and display therapeutic strategies for targeting BCSCs to reverse drug resistance in BC. Even more importantly, more attention should be paid to studies on BCSC-targeted strategies to overcome the drug resistant dilemma of clinical therapies in the future.

Cancer Stem Cell (CSC) Inhibitors in Oncology-A Promise for a Better Therapeutic Outcome: State of the Art and Future Perspectives

Cancer stem cells (CSCs), a subpopulation of cancer cells endowed with self-renewal, tumorigenicity, pluripotency, chemoresistance, differentiation, invasive ability, and plasticity, reside in specialized tumor niches and are responsible for tumor maintenance, metastasis, therapy resistance, and tumor relapse. The new-age "hierarchical or CSC" model of tumor heterogeneity is based on the concept of eradicating CSCs to prevent tumor relapse and therapy resistance. Small-molecular entities and biologics acting on various stemness signaling pathways, surface markers, efflux transporters, or components of complex tumor microenvironment are under intense investigation as potential anti-CSC agents. In addition, smart nanotherapeutic tools have proved their utility in achieving CSC targeting. Several CSC inhibitors in clinical development have shown promise, either as mono- or combination therapy, in refractory and difficult-to-treat cancers. Clinical investigations with CSC marker follow-up as a measure of clinical efficacy are needed to turn the "hype" into the "hope" these new-age oncology therapeutics have to offer.

Drug Repurposing for Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is the most aggressive type of breast cancer which presents a high rate of relapse, metastasis, and mortality. Nowadays, the absence of approved specific targeted therapies to eradicate TNBC remains one of the main challenges in clinical practice. Drug discovery is a long and costly process that can be dramatically improved by drug repurposing, which identifies new uses for existing drugs, both approved and investigational. Drug repositioning benefits from improvements in computational methods related to chemoinformatics, genomics, and systems biology. To the best of our knowledge, we propose a novel and inclusive classification of those approaches whereby drug repurposing can be achieved in silico: structure-based, transcriptional signatures-based, biological networks-based, and data-mining-based drug repositioning. This review specially emphasizes the most relevant research, both at preclinical and clinical settings, aimed at repurposing pre-existing drugs to treat TNBC on the basis of molecular mechanisms and signaling pathways such as androgen receptor, adrenergic receptor, STAT3, nitric oxide synthase, or AXL. Finally, because of the ability and relevance of cancer stem cells (CSCs) to drive tumor aggressiveness and poor clinical outcome, we also focus on those molecules repurposed to specifically target this cell population to tackle recurrence and metastases associated with the progression of TNBC.

The Inhibitory Effect of Curcumin on Hypoxia Inducer Factors (Hifs) as a Regulatory Factor in the Growth of Tumor Cells in Breast Cancer Stem-Like Cells

Hypoxia in the microenvironment is related to chemotherapy resistance, tumor progression, and metastasis. Curcumin, as a phenolic compound extracted from the turmeric, has been used as an anti-cancer agent with low toxicity in recent years. Since curcumin has inhibitory activities against hypoxia-inducible factors (HIFs) in several cancers, this study was conducted to examine the effect of curcumin on MCF-7 cells and cancer stem-like cells (CS-LCs) under hypoxic and normoxic conditions. CS-LCs were isolated from MCF-7 cells using the magnet activated cell sorting (MACS) method based on CD₄₄ ⁺/ CD₂₄ ^- surface markers. The effects of curcumin on the viability of MCF-7 cells and CS-LCs were examined in hypoxic and normoxic conditions using the MTT test. The effects of curcumin on apoptosis and cell cycle of CS-LCs and MCF-7 cells were analyzed using flow cytometry. Moreover, the inhibitory effects of curcumin on the levels of HIF-1 and HIF-2α protein in CS-LCs were investigated using the western blot method. Early apoptosis occurred in CSC-LCs more than MCF-7 cells under hypoxic conditions. Flow cytometry assay showed that curcumin caused cell cycle arrest of CSC-LCs and MCF-7 at the G2/M phase under hypoxic conditions while under normoxic conditions, arrest occurred at the G0/G1 phase in MCF-7 cells and at S and G2/M phases in CS-LCs. Based on the results, the curcumin inhibited the expression of HIF-1 by degrading ARNT in CS-LCs.In conclusion, curcumin has inhibitory effects on MCF- 7 cells and CS- LCs and thus may be used as an antitumor agent.

Antipsychotics drug aripiprazole as a lead against breast cancer cell line (MCF-7) in vitro

Breast cancer is the second leading cause of death among women globally. The existing treatment options for breast cancer are largely associated with severe toxicities, and lower efficacies. Therefore, there is an urgent need for the development of non-toxic effective drugs against breast cancer. For this purpose, drug repositioning strategy was used to evaluate the anti-cancer potential of a library of heterocyclic drugs. The major advantage of drug repurposing is that the pharmacokinetic, pharmacodynamic, and toxicity profiles of drugs are well documented. In the current study, we screened 97 drugs of different chemical classes, and among them aripiprazole, an antipsychotic drug, was found to be sufficiently active against breast cancer cell line MCF-7. Aripiprazole showed a cytotoxicity (IC50 = 12.1 ± 0.40 μM) to MCF-7 cells, comparable to the standard anticancer drug doxorubicin (IC50 = 1.25 ± 0.34 μM). Aripiprazole was also found to be active against other cancer cell lines, including MDA-MB-231 (IC50 = 19.83 ± 0.27 μM), AU565 (IC50 = 18.02 ± 0.44 μM), and BT-474 (IC50 = 36.42 ± 0.12 μM). Aripiprazole significantly inhibited the cell cycle progression at subG0G1 phase, and enhanced apoptosis in MCF-7 breast cancer cells. The drug was also able to significantly increase the nuclear condensation, and modulated the expression of certain genes involved in breast cancer, such as caspases 3, and 9, BAK-1, C-MYC, BCL2L1, BCL-10, and BCL-2. Further studies are needed to explore the effect of aripiprazole on intrinsic and extrinsic pathways of apoptosis in cancer cells.

Understanding Breast cancer: from conventional therapies to repurposed drugs

Breast cancer is the most common cancer among women and is considered a developed country disease. Moreover, is a heterogenous disease, existing different types and stages of breast cancer development, therefore, better understanding of cancer biology, helps to improve the development of therapies. The conventional treatments accessible after diagnosis, have the main goal of controlling the disease, by improving survival. In more advance stages the aim is to prolong life and symptom palliation care. Surgery, radiation therapy and chemotherapy are the main options available, which must be adapted to each person individually. However, patients are developing resistance to the conventional therapies. This resistance is due to alterations in important regulatory pathways such as PI3K/AKt/mTOR, this pathway contributes to trastuzumab resistance, a reference drug to treat breast cancer. Therefore, is proposed the repurposing of drugs, instead of developing drugs de novo, for example, to seek new medical treatments within the drugs available, to be used in breast cancer treatment. Providing safe and tolerable treatments to patients, and new insights to efficacy and efficiency of breast cancer treatments. The economic and social burden of cancer is enormous so it must be taken measures to relieve this burden and to ensure continued access to therapies to all patients. In this review we focus on how conventional therapies against breast cancer are leading to resistance, by reviewing those mechanisms and discussing the efficacy of repurposed drugs to fight breast cancer.

Antiparkinson Drug Benztropine Suppresses Tumor Growth, Circulating Tumor Cells, and Metastasis by Acting on SLC6A3/DAT and Reducing STAT3

Tumor growth, progression, and therapy resistance are crucial factors in the prognosis of cancer. The properties of three-dimensional (3D) tumor-like organoids (tumoroids) more closely resemble in vivo tumors compared to two-dimensionally cultured cells and are therefore effectively used for assays and drug screening. We here established a repurposed drug for novel anticancer research and therapeutics using a 3D tumoroid-based screening system. We screened six pharmacologically active compounds by using an original tumoroid-based multiplex phenotypic screening system with a matrix metalloproteinase 9 (MMP9) promoter-driven fluorescence reporter for the evaluation of both tumoroid formation and progression. The antiparkinson drug benztropine was the most effective compound uncovered by the screen. Benztropine significantly inhibited in vitro tumoroid formation, cancer cell survival, and MMP9 promoter activity. Benztropine also reduced the activity of oncogenic signaling transducers and trans-activators for MMP9, including STAT3, NF-κB, and β-catenin, and the properties of cancer stem cells/cancer-initiating cells. Benztropine and GBR-12935 directly targeted the dopamine transporter DAT/SLC6A3, whose genetic alterations such as amplification were correlated with poor prognosis for cancer patients. Benztropine also inhibited the tumor growth, circulating tumor cell (CTC) number, and rate of metastasis in a tumor allograft model in mice. In conclusion, we propose the repurposing of benztropine for anticancer research and therapeutics that can suppress tumor progression, CTC, and metastasis of aggressive cancers by reducing key pro-tumorigenic factors.

Machine learning for target discovery in drug development

The discovery of macromolecular targets for bioactive agents is currently a bottleneck for the informed design of chemical probes and drug leads. Typically, activity profiling against genetically manipulated cell lines or chemical proteomics is pursued to shed light on their biology and deconvolute drug-target networks. By taking advantage of the ever-growing wealth of publicly available bioactivity data, learning algorithms now provide an attractive means to generate statistically motivated research hypotheses and thereby prioritize biochemical screens. Here, we highlight recent successes in machine intelligence for target identification and discuss challenges and opportunities for drug discovery.

Integrated transcriptomics reveals master regulators of lung adenocarcinoma and novel repositioning of drug candidates

BACKGROUND

Lung adenocarcinoma is the major cause of cancer-related deaths in the world. Given this, the importance of research on its pathophysiology and therapy remains a key health issue. To assist in this endeavor, recent oncology studies are adopting Systems Biology approaches and bioinformatics to analyze and understand omics data, bringing new insights about this disease and its treatment.

METHODS

We used reverse engineering of transcriptomic data to reconstruct nontumorous lung reference networks, focusing on transcription factors (TFs) and their inferred target genes, referred as regulatory units or regulons. Afterwards, we used 13 case-control studies to identify TFs acting as master regulators of the disease and their regulatory units. Furthermore, the inferred activation patterns of regulons were used to evaluate patient survival and search drug candidates for repositioning.

RESULTS

The regulatory units under the influence of ATOH8, DACH1, EPAS1, ETV5, FOXA2, FOXM1, HOXA4, SMAD6, and UHRF1 transcription factors were consistently associated with the pathological phenotype, suggesting that they may be master regulators of lung adenocarcinoma. We also observed that the inferred activity of FOXA2, FOXM1, and UHRF1 was significantly associated with risk of death in patients. Finally, we obtained deptropine, promazine, valproic acid, azacyclonol, methotrexate, and ChemBridge ID compound 5109870 as potential candidates to revert the molecular profile leading to decreased survival.

CONCLUSION

Using an integrated transcriptomics approach, we identified master regulator candidates involved with the development and prognostic of lung adenocarcinoma, as well as potential drugs for repurposing.

FDA-drug screening identifies deptropine inhibiting hepatitis E virus involving the NF-κB-RIPK1-caspase axis

Hepatitis E virus (HEV) infection is the leading cause of acute hepatitis worldwide and can develop into chronic infection in immunocompromised patients, promoting the development of effective antiviral therapies. In this study, we performed a screening of a library containing over 1000 FDA-approved drugs. We have identified deptropine, a classical histamine H1 receptor antagonist used to treat asthmatic symptoms, as a potent inhibitor of HEV replication. The anti-HEV activity of deptropine appears dispensable of the histamine pathway, but requires the inhibition on nuclear factor-κB (NF-κB) activity. This further activates caspase mediated by receptor-interacting protein kinase 1 (RIPK1) to restrict HEV replication. Given deptropine being widely used in the clinic, our results warrant further evaluation of its anti-HEV efficacy in future clinical studies. Importantly, the discovery that NF-κB-RIPK1-caspase pathway interferes with HEV infection reveals new insight of HEV-host interactions.

Anti-metastasis activity of curcumin against breast cancer via the inhibition of stem cell-like properties and EMT

BACKGROUND

Curcumin is a polyphenolic compound with potent chemopreventive and anti-cancer efficacy.

PURPOSE

To explore the potential anti-metastasis efficacy of curcumin in breast cancer stem-like cells (BCSCs), which are increasingly considered to be the origin of the recurrence and metastasis of breast cancer.

METHODS

A CCK8 assay was performed to evaluate cell viability, and a colony formation assay was conducted to determine cell proliferation in MCF-7 and MDA-MB-231 adherent cells. Transwell and wound healing assays were used to detect the effect of curcumin on cell migration and invasion in MDA-MB-231 cells. Mammospheres were cultured with serum free medium (SFM) for three generations and the BCSC surface marker CD44⁺CD24^-/^low subpopulation was measured by flow cytometry. Mammosphere formation and differentiation abilities were determined after cell treatment with curcumin. Then, a reverse transcription-quantitative polymerase chain reaction assay was conducted to detect the relative mRNA level of epithelial-mesenchymal transition (EMT) marker genes and western blot analysis was performed to determine the protein expression of stem cell genes in mammospheres treated with curcumin.

RESULTS

Curcumin exhibited anti-proliferative and colony formation inhibiting activities in both the MCF-7 and MDA-MB-231 cell lines. It also suppressed the migration and invasion of MDA-MB-231 cells. The CD44⁺CD24^-/^low subpopulation was larger in mammospheres when MCF-7 and MDA-MB-231 adherent cells were cultured with SFM. Further studies revealed that curcumin inhibited mammosphere formation and differentiation abilities. Moreover, curcumin down-regulated the mRNA expression of Vimentin, Fibronectin, and β-catenin, and up-regulated E-cadherin mRNA expression levels. Western blot analysis demonstrated that curcumin decreased the protein expression of stem cell genes including Oct4, Nanog and Sox2.

CONCLUSION

The results of the present study suggest that the inhibitor effects of curcumin on breast cancer cells may be related to resistance to cancer stem-like characters and the EMT process. These data indicate that curcumin could function as a type of anti-metastasis agent for breast cancer.

Preventive action of benztropine on platinum-induced peripheral neuropathies and tumor growth

The endogenous cholinergic system plays a key role in neuronal cells, by suppressing neurite outgrowth and myelination and, in some cancer cells, favoring tumor growth. Platinum compounds are widely used as part of first line conventional cancer chemotherapy; their efficacy is however limited by peripheral neuropathy as a major side-effect. In a multiple sclerosis mouse model, benztropine, that also acts as an anti-histamine and a dopamine re-uptake inhibitor, induced the differentiation of oligodendrocytes through M1 and M3 muscarinic receptors and enhanced re-myelination. We have evaluated whether benztropine can increase anti-tumoral efficacy of oxaliplatin, while preventing its neurotoxicity.We showed that benztropine improves acute and chronic clinical symptoms of oxaliplatin-induced peripheral neuropathies in mice. Sensory alterations detected by electrophysiology in oxaliplatin-treated mice were consistent with a decreased nerve conduction velocity and membrane hyperexcitability due to alterations in the density and/or functioning of both sodium and potassium channels, confirmed by action potential analysis from ex-vivo cultures of mouse dorsal root ganglion sensory neurons using whole-cell patch-clamp. These alterations were all prevented by benztropine. In oxaliplatin-treated mice, MBP expression, confocal and electronic microscopy of the sciatic nerves revealed a demyelination and confirmed the alteration of the myelinated axons morphology when compared to animals injected with oxaliplatin plus benztropine. Benztropine also prevented the decrease in neuronal density in the paws of mice injected with oxaliplatin. The neuroprotection conferred by benztropine against chemotherapeutic drugs was associated with a lower expression of inflammatory cytokines and extended to diabetic-induced peripheral neuropathy in mice.Mice receiving benztropine alone presented a lower tumor growth when compared to untreated animals and synergized the anti-tumoral effect of oxaliplatin, a phenomenon explained at least in part by benztropine-induced ROS imbalance in tumor cells.This report shows that blocking muscarinic receptors with benztropine prevents peripheral neuropathies and increases the therapeutic index of oxaliplatin. These results can be rapidly transposable to patients as benztropine is currently indicated in Parkinson's disease in the United States.

TAp73 Modifies Metabolism and Positively Regulates Growth of Cancer Stem-Like Cells in a Redox-Sensitive Manner

PURPOSE

Stem-like cancer cells, with characteristic self-renewal abilities, remain highly refractory to various clinical interventions. As such, stemness-inhibiting entities, such as tumor suppressor p53, are therapeutically pursued for their anticancer activities. Interestingly, similar implications for tumor suppressor TAp73 in regulating stemness features within stem-like cancer cells remain unknown.Experimental Design: This study utilizes various in vitro molecular biology techniques, including immunoblotting, qRT-PCR, and mass spectrometry-based proteomics, and metabolomics approaches to study the role of TAp73 in human and murine embryonal carcinoma stem-like cells (ECSLC) as well as human breast cancer stem-like cells (BCSLC). These findings were confirmed using patient-derived brain tumor-initiating cells (BTIC) and in vivo xenograft models.

RESULTS

TAp73 inhibition decreases the expression of stem cell transcription factors Oct4, Nanog, and Sox-2, as well as tumorsphere formation capacity in ECSLCs. In vivo, TAp73-deficient ECSLCs and BCSLCs demonstrate decreased tumorigenic potential when xenografted in mice. Mechanistically, TAp73 modifies the proline regulatory axis through regulation of enzymes GLS, OAT, and PYCR1 involved in the interconversion of proline-glutamine-ornithine. Further, TAp73 deficiency exacerbates glutamine dependency, enhances accumulation of reactive oxygen species through reduced superoxide dismutase 1 (SOD1) expression, and promotes differentiation by arresting cell cycle and elevating autophagy. Most importantly, the knockdown of TAp73 in CD133^HI BTICs, separated from three different glioblastoma patients, strongly decreases the expression of prosurvival factors Sox-2, BMI-1, and SOD1, and profoundly decreases their self-renewal capacity as evidenced through their reduced tumorsphere formation ability.

CONCLUSIONS

Collectively, we reveal a clinically relevant aspect of cancer cell growth and stemness regulation through TAp73-mediated redox-sensitive metabolic reprogramming.

Targeting the FKBP51/GR/Hsp90 Complex to Identify Functionally Relevant Treatments for Depression and PTSD

Genetic and epigenetic alterations in FK506-binding protein 5 ( FKBP5) have been associated with increased risk for psychiatric disorders, including post-traumatic stress disorder (PTSD). Some of these common variants can increase the expression of FKBP5, the gene that encodes FKBP51. Excess FKBP51 promotes hypothalamic-pituitary-adrenal (HPA) axis dysregulation through altered glucocorticoid receptor (GR) signaling. Thus, we hypothesized that GR activity could be restored by perturbing FKBP51. Here, we screened 1280 pharmacologically active compounds and identified three compounds that rescued FKBP51-mediated suppression of GR activity without directly activating GR. One of the three compounds, benztropine mesylate, disrupted the association of FKBP51 with the GR/Hsp90 complex in vitro. Moreover, we show that removal of FKBP51 from this complex by benztropine restored GR localization in ex vivo brain slices and primary neurons from mice. In conclusion, we have identified a novel disruptor of the FKBP51/GR/Hsp90 complex. Targeting this complex may be a viable approach to developing treatments for disorders related to aberrant FKBP51 expression.

Suppression of TAFI by siRNA inhibits invasion and migration of breast cancer cells

Human thrombin activatable fibrinolysis inhibitor (TAFI), also known as carboxypeptidase B2 (CPB2), is a procarboxypeptidase enzyme. The purpose of the present study was to observe the expression of TAFI in breast cancer (BC) and breast cancer cell (BCC) lines and to investigate the effect of TAFI suppression by small interfering (si)RNA gene silencing on invasion and migration of BCC lines. A significant increase in TAFI level was identified by immunohistochemical analysis in BC tissues compared with normal breast tissues. TAFI suppression also inhibited cell viability, invasion and migration ability as demonstrated by MTT, Transwell chamber, and wound scratch assays, respectively (P<0.05). The data suggested that suppression of TAFI by siRNA inhibits invasion and migration of breast cancer cells and that TAFI may be a new target for breast cancer therapy.