Beta-catenin mediates the apoptosis induction effect of celastrol in HT29 cells

Design, synthesis and evaluation of the novel chalcone derivatives with 2,2-dimethylbenzopyran as HIF-1 inhibitors that possess anti-angiogenic potential

Hypoxia-inducible factor-1 (HIF-1) as a key mediator in tumor metastasis, angiogenesis and poor patient prognosis, has been recognized as an important cancer drug target. Up to now, some HIF-1 inhibitors with diverse skeletal structures were reported as anticancer agents, mostly natural product-derived compounds. In this study, we designed and synthesized a series of chalcone-based compounds with 2,2-dimethylbenzopyran using the combination principles to select benzopyrans and chalcones natural products. A novel series of chalcone-based compounds with 2,2-dimethylbenzopyran were evaluated as HIF-1 inhibitor. HRE luciferase reporter assay demonstrated compounds showed superior HIF-1 inhibitory activity. Among them, compound 16e exhibited the best features: the strongest HIF-1 inhibitory activity (IC₅₀ = 2.38 μM, 3-fold higher than that of LXH-SYP-7). Meanwhile, it also significantly suppressed migration and VEGF-induced invasion of A549 cells in nontoxic concentrations. Additionally, tube formation assay demonstrated its anti-angiogenesis activity. Moreover, the in vivo study indicated that compound 16e could retard angiogenesis in the matrigel plug assay model, and almost no new blood vessels were formed in the suppository when it reached 20 μM. Finally, we also performed a subchronic toxicity test in which doses up to 50 mg/kg were administered orally for 10 days in Kunming mice with no toxic adverse effects and were well tolerated. These findings support the further investigation on the anti-invasive and anti-angiogenic potential of this class of compounds as HIF-1 inhibitor.

Celastrol and Resveratrol Modulate SIRT Genes Expression and Exert Anticancer Activity in Colon Cancer Cells and Cancer Stem-like Cells

Simple Summary

The recovery rate in patients with metastatic colorectal cancer (CRC) remains low and declines with successive lines of treatment. This phenomenon is caused by the development of drug resistance and the presence of colorectal cancer stem cells (CSCs). Phytochemicals, like -celastrol and resveratrol, are very promising for colon cancer therapy, owing to their low or no toxicity and their pleiotropic activity, enabling them to interact with various biological targets. In the present study, the potential anticancer mechanisms of both compounds against metastatic colon cancer cells and the capacity to eradicate CSCs were investigated.

Abstract

Metastatic colorectal cancer (CRC) remains a hard-to-cure neoplasm worldwide. Its curability declines with successive lines of treatment due to the development of various cancer resistance mechanisms and the presence of colorectal cancer stem cells (CSCs). Celastrol and resveratrol are very promising phytochemicals for colon cancer therapy, owing to their pleiotropic activity that enables them to interact with various biological targets. In the present study, the anticancer activities of both compounds were investigated in metastatic colon cancer cells (LoVo cells) and cancer stem-like cells (LoVo/DX). We showed that celastrol is a very potent anti-tumor compound against metastatic colon cancer, capable of attenuating CSC-like cells at the molecular and cellular levels. In contrast, resveratrol has a much greater effect on colon cancer cells that are expressing standard sensitivity to anticancer drugs, than on CSC-like cells. In addition, both polyphenols have different influences on the expression of SIRT genes, which seems to be at least partly related to their anti-tumor activity.

TMT-Based Quantitative Proteomic Analysis Identified Proteins and Signaling Pathways Involved in the Response to Xanthatin Treatment in Human HT-29 Colon Cancer Cells

BACKGROUND

Xanthatin is a plant-derived bioactive sesquiterpene lactone from the Xanthium strumarium L., and it has been used as a traditional Chinese medicine. Recently, many studies have reported that xanthatin has anticancer activity. However, a comprehensive understanding of the mechanism underlying the antitumor effects of xanthatin is still lacking.

OBJECTIVE

To systematically and comprehensively identify the underlying mechanisms of xanthatin on cancer cells, quantitative proteomic techniques were performed.

METHODS

Xanthatin induced HT-29 colon cancer cells death was detected by lactate dehydrogenase (LDH) release cell death assay. Differentially abundant proteins in two groups (control groups and xanthatin treatment groups) of human HT-29 colon cancer cells were identified using tandem mass tag (TMT) quantitative proteomic techniques. All the significant differentially abundant proteins were generally characterized by performing hierarchical clustering, Gene Ontology (GO) enrichment analyses and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. We chose Western blot analysis to validate the candidate proteins in the proteomics results.

RESULTS

A total of 5637 proteins were identified, of which 397 significantly differentially abundant proteins in the groups were quantified. Based on the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses, we found that p53-related signaling played an important role in xanthatin-treated HT-29 colon cancer cells. p53-upregulated modulator of apoptosis (Puma), Sestrin-2 and p14ARF, which were selected from among p53-related signaling proteins, were further validated, and the results were consistent with the tandem mass tag quantitative proteomic results.

CONCLUSION

We first investigated the molecular mechanism underlying the effects of xanthatin treatment on HT-29 colon cancer cells using tandem mass tag quantitative proteomic methods and provided a global comprehensive understanding of the antitumor effects of xanthatin. However, it is necessary to further confirm the function of the differentially abundant proteins and the potentially associated signaling pathways.

Design, synthesis of novel celastrol derivatives and study on their antitumor growth through HIF-1α pathway

Four series of hypoxia-inducible factor-1 alpha (HIF-1α) functioning derivatives stemming from modifications to the C-29 carboxyl group of celastrol were designed and synthesized, and their anticancer activities were evaluated. To address the structure and activity relationship of each derivative, extensive structural changes were made. HRE luciferase reporter assay demonstrated that 12 modified compounds showed superior HIF-1α inhibitory activity. Among them, compound C6 exhibited the best features: firstly, the strongest HIF-1α inhibitory activity (IC₅₀ = 0.05 μM, 5-fold higher than that of celastrol); secondly, lower cytotoxicity (22-fold lower, C6-16.85 μM vs celastrol-0.76 μM). Thus, the safety factor of C6 was about 112 times higher than that of celastrol. Western blot assay indicated that C6 may inhibit the expression of HIF-1α protein in cells. Additionally, C6 hindered tumor cell cloning, migration and induced cell apoptosis. It is worth mentioning that in the mouse tumor xenograft model, C6 (10 mg/kg) displayed good antitumor activity in vivo, showing a better inhibition rate (74.03%) than the reference compound 5-fluorouracil (inhibition rate, 59.58%). However, the celastrol treatment group experienced collective death after four doses of the drug. Moreover, C6 minimally affected the mouse weight, indicating that its application in vivo has little toxic effect. H&E staining experiments show that it could also exacerbate the degree of tumor cell damage. The results of water solubility experiment show that the solubility of C6 is increased by 1.36 times than that of celastrol. In conclusion, C6 is a promising antitumor agent through HIF-1α pathway.

Biosynthesis, total synthesis, structural modifications, bioactivity, and mechanism of action of the quinone-methide triterpenoid celastrol

Celastrol, a quinone-methide triterpenoid, was extracted from Tripterygium wilfordii Hook. F. in 1936 for the first time. Almost 70 years later, it is considered one of the molecules most likely to be developed into modern drugs, as it exhibits notable bioactivity, including anticancer and anti-inflammatory activity, and exerts antiobesity effects. In addition, the molecular mechanisms underlying its bioactivity are being widely studied, which offers new avenues for its development as a pharmaceutical reagent. Owing to its potential therapeutic effects and unique chemical structure, celastrol has attracted considerable interest in the fields of organic, biosynthesis, and medicinal chemistry. As several steps in the biosynthesis of celastrol have been revealed, the mechanisms of key enzymes catalyzing the formation and postmodifications of the celastrol scaffold have been gradually elucidated, which lays a good foundation for the future heterogeneous biosynthesis of celastrol. Chemical synthesis is also an effective approach to obtain celastrol. The total synthesis of celastrol was realized for the first time in 2015, which established a new strategy to obtain celastroid natural products. However, owing to the toxic effects and suboptimal pharmacological properties of celastrol, its clinical applications remain limited. To search for drug-like derivatives, several structurally modified compounds were synthesized and tested. This review focuses primarily on the latest research progress in the biosynthesis, total synthesis, structural modifications, bioactivity, and mechanism of action of celastrol. We anticipate that this paper will facilitate a more comprehensive understanding of this promising compound and provide constructive references for future research in this field.

Celastrol Loaded Nanoparticles With ROS-Response and ROS-Inducer for the Treatment of Ovarian Cancer

Ovarian cancer is a gynecological cancer from which it is difficult to be completely cured. It is common to use regimens as an effective treatment for ovarian cancer, but these inevitably bring serious side effects. New treatment strategies and special drugs are needed to improve the prognosis of patients. Celastrol is a natural product, isolated from traditional medicine, that has been proven to be curative for inflammation and cancers. However, the non-targeting and low solubility of celastrol limit its clinical application. We prepared celastrol-loaded nanoparticles for the efficient treatment of ovarian cancer via oxidative stress amplification. In this work, a tumor-targeted, ROS-sensitive nanoparticle was designed, synthesized, and assembled into a drug delivery system that used celastrol. Folic acid (FA) groups on the surface of nanoparticles guide them to actively target the surface of the tumor cell membrane. Thioketal (TK) bonds in nanoparticles can be oxidized and broken into -SH within the ROS level of tumor tissues, which causes the breaking of the PEG hydrophilic shell layer of nanoparticles and promotes the release of celastrol. The released celastrol further stimulated the production of ROS and amplified the intracellular ROS level to promote the apoptosis of tumor cells, thus achieving a therapeutic effect on the celastrol treated ovarian cancer.

LKB1 and YAP phosphorylation play important roles in Celastrol-induced β-catenin degradation in colorectal cancer

Wnt/β-catenin and Hippo pathways play essential roles in the tumorigenesis and development of colorectal cancer. We found that Celastrol, isolated from Tripterygium wilfordii plant, exerted a significant inhibitory effect on colorectal cancer cell growth in vitro and in vivo, and further unraveled the molecular mechanisms. Celastrol induced β-catenin degradation through phosphorylation of Yes-associated protein (YAP), a major downstream effector of Hippo pathway, and also Celastrol-induced β-catenin degradation was dependent on liver kinase B1 (LKB1). Celastrol increased the transcriptional activation of LKB1, partially through the heat shock factor 1 (HSF1). Moreover, LKB1 activated AMP-activated protein kinase α (AMPKα) and further phosphorylated YAP, which eventually promoted the degradation of β-catenin. In addition, LKB1 deficiency promoted colorectal cancer cell growth and attenuated the inhibitory effect of Celastrol on colorectal cancer growth both in vitro and in vivo. Taken together, Celastrol inhibited colorectal cancer cell growth by promoting β-catenin degradation via the HSF1–LKB1–AMPKα–YAP pathway. These results suggested that Celastrol may potentially serve as a future drug for colorectal cancer treatment.

Systematic identification of Celastrol-binding proteins reveals that Shoc2 is inhibited by Celastrol

Colorectal cancer (CRC) is the third most commonly diagnosed cancer. Celastrol exhibits anti-tumor activities in a variety of cancers. However, the effect of Celastrol on human CRC and the underlying mechanisms still need to be elucidated. The present study aimed to use in vitro and in vivo methods to clarify the anti-tumor effect of Celastrol and use protein microarrays to explore its mechanisms. We demonstrated that Celastrol effectively inhibited SW480 CRC cell proliferation. Two weeks of Celastrol gavage significantly inhibited the growth of xenografts in nude mice. A total of 69 candidate proteins were identified in the protein microarray experiment, including the most highly enriched protein Shoc2, which is a scaffold protein that modulates cell motility and metastasis through the ERK pathway. Celastrol significantly inhibited ERK1/2 phosphorylation in cell lines and xenograft tumors. Down-regulation of Shoc2 expression using Shoc2 siRNA also inhibited ERK1/2 phosphorylation. Furthermore, down-regulation of Shoc2 expression also significantly inhibited proliferation, colony formation, and migration functions of tumor cells. In addition, the LD0 of Celastrol by gavage is equal or more than 80 mg/kg in C57 male mice. In summary, we unraveled the anti-CRC function of Celastrol and confirmed for the first time that it inhibited the ERK1/2 pathway through binding to Shoc2.

Celastrol Suppresses Tryptophan Catabolism in Human Colon Cancer Cells as Revealed by Metabolic Profiling and Targeted Metabolite Analysis

Celastrol is well known for its anti-cancer effects, yet its specific mechanisms against colon cancer are still not fully elucidated. In this study, cytotoxic effect of celastrol against HCT116 colon cancer cells was investigated based on cell viability assay and flow cytometry assay, and the possible mechanism was explored using a strategy combining metabolic profiling and targeted metabolite analysis based on ultra performance liquid chromatography (UPLC)/MS. Celastrol was found to inhibit the growth of colon cancer cells and induce apoptosis. Metabolomics analysis revealed characteristic changes in metabolic profiles of the colon cancer cells, revealing altered levels of amino acids, carnitine, and lipid markers. Most interestingly, with the assistance of targeted metabolite analysis, tryptophan (Trp) level was significantly increased whereas kynurenine (Kyn) level was decreased in colon cancer cells after celastrol treatment, together with markedly declined Kyn/Trp ratios. Western blot analysis revealed that expression of indoleamine 2,3-dioxygenase (IDO), the enzyme catalyzing Trp to generate Kyn, was dramatically inhibited in colon cancer cells after celastrol treatment, with a dose-dependent manner. These results suggest that suppression of IDO expression and tryptophan catabolism may be part of the mechanisms of celastrol in its cytotoxic effect against HCT116 colon cancer cells. This study provided scientific basis for further development of celastrol on treating colon cancer.

Multiple oncogenic roles of nuclear beta-catenin

β-Catenin is essential for embryonic development and required for cell renewal/regeneration in adult life. Cellular β-catenin exists in three different pools: membranous, cytoplasmic and nuclear. In this review, we focus on functions of the nuclear pool in relation to tumorigenesis. In the nucleus, beta-catenin functions as both activator and repressor of transcription in a context-dependent manner. It promotes cell proliferation and supports tumour growth by enhancing angiogenesis. β-Catenin-mediated signalling regulates cancer cell metabolism and is associated with tumour-initiating cells in multiple malignancies. In addition, it functions as both pro- and anti-apoptotic factor besides acting to inhibit recruitment of inflammatory anti-tumour T-cells. Thus, β-catenin appears to possess a multifaceted nuclear function that may significantly impact tumour initiation and progression.

Celastrol attenuates incision-induced inflammation and pain associated with inhibition of the NF-κB signalling pathway via SARM

AIM

This study aimed to investigate whether celastrol (CEL) could alleviate incision-induced pain and decipher its possible mechanism.

MATERIALS AND METHODS

Sprague-Dawley rats were randomly divided into five groups: naïve, vehicle, CEL (5 μg/paw, 10 μg/paw and 20 μg/paw). CEL or vehicle was administered intraplantarly before plantar surgical incision. Histological examinations of skin tissues were performed after HE staining. Additionally, immunohistochemical staining, RT-PCR and western blot were performed to analyse macrophages, proinflammatory cytokines, SARM and NF-κB expression, respectively. Moreover, the previous mentioned factors were re-evaluated after suppressing SARM expression by shRNA.

KEY FINDINGS

The plantar incision rats displayed pain-related behaviours and inflammatory infiltration in the skin. The mRNA levels of proinflammatory cytokines, such as IL-1β, IL-6, and TNFα were significantly upregulated in the skin of surgical rats. The expression of sterile α- and armadillo-motif-containing protein (SARM) was downregulated and nuclear factor kappa-B (NF-κB) was activated. Interestingly, CEL could partially restore the pain-related behavioural changes. Furthermore, molecular mechanism of CEL was explored, that included significantly reduction of proinflammatory cytokines mRNA expressions, a significant decrease of p-p65 and p65 levels and a markedly increase of SARM and IkBα expressions in skin tissues. However, supression SARM by shRNA partially eliminated those protective effect of CEL.

SIGNIFICANCE

Our data suggest that intraplantarly administration of CEL attenuates inflammatory and acute pain. This finding could be attributed to regulation of the NF-κB signalling pathway via SARM. These results provide pre-clinical evidence supporting the use of CEL in the treatment of surgical pain.

A Mechanistic Overview of Triptolide and Celastrol, Natural Products from Tripterygium wilfordii Hook F

Triptolide and celastrol are predominantly active natural products isolated from the medicinal plant Tripterygium wilfordii Hook F. These compounds exhibit similar pharmacological activities, including anti-cancer, anti-inflammation, anti-obesity, and anti-diabetic activities. Triptolide and celastrol also provide neuroprotection and prevent cardiovascular and metabolic diseases. However, toxicity restricts the further development of triptolide and celastrol. In this review, we comprehensively review therapeutic targets and mechanisms of action, and translational study of triptolide and celastrol. We systemically discuss the structure-activity-relationship of triptolide, celastrol, and their derivatives. Furthermore, we propose the use of structural derivatives, targeted therapy, and combination treatment as possible solutions to reduce toxicity and increase therapeutic window of these potent natural products from T. wilfordii Hook F.

Celastrol Ameliorates Ulcerative Colitis-Related Colorectal Cancer in Mice via Suppressing Inflammatory Responses and Epithelial-Mesenchymal Transition

Celastrol, also named as tripterine, is a pharmacologically active ingredient extracted from the root of traditional Chinese herb Tripterygium wilfordii Hook F with potent anti-inflammatory and anti-tumor activities. In the present study, we investigated the effects of celastrol on ulcerative colitis-related colorectal cancer (UC-CRC) as well as CRC in vivo and in vitro and explored its underlying mechanisms. UC-CRC model was induced in C57BL/6 mice by administration of azoxymethane (AOM) and dextran sodium sulfate (DSS). Colonic tumor xenograft models were developed in BALB/c-nu mice by subcutaneous injection with HCT116 and HT-29 cells. Intragastric administration of celastrol (2 mg/kg/d) for 14 weeks significantly increased the survival ratio and reduced the multiplicity of colonic neoplasms compared with AOM/DSS model mice. Mechanically, celastrol treatment significantly prevented AOM/DSS-induced up-regulation of expression levels of oncologic markers including mutated p53 and phospho-p53, β-catenin and proliferating cell nuclear antigen (PCNA). In addition, treatment with celastrol inhibited inflammatory responses, as indicated by the decrease of serum tumor necrosis factor-α (TNF-α), interleukin (IL)-1β and IL-6, down-regulation of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS), and inactivation of nuclear factor κB (NF-κB). Moreover, celastrol obviously suppressed epithelial-mesenchymal transition (EMT) through up-regulating E-cadherin and down-regulating N-cadherin, Vimentin and Snail. Additionally, we also demonstrated that celastrol inhibited human CRC cell proliferation and attenuated colonic xenograft tumor growth via reversing EMT. Taken together, celastrol could effectively ameliorate UC-CRC by suppressing inflammatory responses and EMT, suggesting a potential drug candidate for UC-CRC therapy.

SOX7 interferes with β-catenin activity to promote neuronal apoptosis

SOX7 mediates various developmental processes. However, its role in neuronal apoptosis remains unclear. In the present study, we investigated the expression pattern and role of SOX7 in potassium deprivation-induced rat cerebellar granule neuron apoptosis. Our results showed that both mRNA and protein levels of SOX7 were upregulated when potassium was deprived. SOX7 overexpression promoted neuronal apoptosis, whereas knockdown of SOX7 protected neurons against apoptosis. Moreover, we found that β-catenin activity was suppressed during apoptosis and that β-catenin inhibition was crucial for potassium deprivation-induced neuronal apoptosis. This suppression was mediated by an interaction between SOX7 and β-catenin but not by protein degradation. Lastly, we showed that β-catenin inhibition mediated the pro-apoptotic effect of SOX7. Together, our findings demonstrated that SOX7 interfered with β-catenin activity to promote neuronal apoptosis, which acted as a novel signaling mechanism in neuronal cell death.

Novel cancer chemotherapy hits by molecular topology: dual Akt and Beta-catenin inhibitors

Background and Purpose

Colorectal and prostate cancers are two of the most common types and cause of a high rate of deaths worldwide. Therefore, any strategy to stop or at least slacken the development and progression of malignant cells is an important therapeutic choice. The aim of the present work is the identification of novel cancer chemotherapy agents. Nowadays, many different drug discovery approaches are available, but this paper focuses on Molecular Topology, which has already demonstrated its extraordinary efficacy in this field, particularly in the identification of new hit and lead compounds against cancer. This methodology uses the graph theoretical formalism to numerically characterize molecular structures through the so called topological indices. Once obtained a specific framework, it allows the construction of complex mathematical models that can be used to predict physical, chemical or biological properties of compounds. In addition, Molecular Topology is highly efficient in selecting and designing new hit and lead drugs. According to the aforementioned, Molecular Topology has been applied here for the construction of specific Akt/mTOR and β-catenin inhibition mathematical models in order to identify and select novel antitumor agents.

Experimental Approach

Based on the results obtained by the selected mathematical models, six novel potential inhibitors of the Akt/mTOR and β-catenin pathways were identified. These compounds were then tested in vitro to confirm their biological activity.

Conclusion and Implications

Five of the selected compounds, CAS n° 256378-54-8 (Inhibitor n°1), 663203-38-1 (Inhibitor n°2), 247079-73-8 (Inhibitor n°3), 689769-86-6 (Inhibitor n°4) and 431925-096 (Inhibitor n°6) gave positive responses and resulted to be active for Akt/mTOR and/or β-catenin inhibition. This study confirms once again the Molecular Topology’s reliability and efficacy to find out novel drugs in the field of cancer.

Interference with the β-catenin gene in gastric cancer induces changes to the miRNA expression profile

Aberrant activation of the Wnt/β-catenin signaling pathway plays a major role in carcinogenesis and the progression of many malignant tumors, especially gastric cancer (GC). Some research has suggested that expression of the β-catenin protein is associated with clinicopathologic factors and affects the biological behaviors of GC cells. However, the mechanism of these effects is not yet clear. Studies show that the Wnt/β-catenin pathway regulates some miRNAs. We hypothesize that oncogenic activation of β-catenin signaling is involved in the formation of GC through regulating certain microRNAs (miRNAs). The results of the current study demonstrate that expression of the β-catenin protein is associated with many clinicopathologic characteristics including the degree of differentiation, depth of tumor invasion, tumor site, and 5-year survival rate. We found that silencing the expression of β-catenin with lentiviruses could delay cell proliferation, promote apoptosis, weaken the invasive power of GC cells, and increase the sensitivity of GC cells to 5-fluorouracil in vitro. Using miRNA microarrays to detect changes in the miRNA transcriptome following interference with β-catenin in GC cells, we found that miR-1234-3p, miR-135b-5p, miR-210, and miR-4739 were commonly upregulated and that miR-20a-3p, miR-23b-5p, miR-335-3p, miR-423-5p, and miR-455-3p were commonly downregulated. These data provide a theoretical basis for the potential interaction between miRNA and the β-catenin signaling pathway in GC.

Secretory Leukocyte Protease Inhibitor (SLPI) expression downregulates E-cadherin, induces β-catenin re-localisation and triggers apoptosis-related events in breast cancer cells

BACKGROUND INFORMATION

Epithelial cadherin (E-cadherin) is involved in cell-cell adhesion through its extracellular domain, whereas the intracellular domain interacts with adaptor proteins, i.e. β-catenin, links E-cadherin to the actin cytoskeleton and participates in signal transduction events. E-cadherin protects mammary epithelial cells from apoptosis and its loss during tumour progression has been documented. Secretory Leukocyte Protease Inhibitor (SLPI) has anti- and pro-tumourigenic activities but its role in breast cancer has not been fully elucidated. Notwithstanding its relevance, how SLPI affects E-cadherin in breast cancer is still unknown. This study evaluated the effect of SLPI upon E-cadherin/β-catenin expression and apoptosis-related markers in murine (F3II) and human (MCF-7) breast tumour cells either treated with exogenous recombinant human SLPI (rhSLPI) or stably transfected with a plasmid encoding its sequence.

RESULTS

Addition of rhSLPI to F3II cells caused a decrease (P < 0.05) in E-cadherin transcript and protein levels. Similar results were observed in SLPI-stable F3II transfectants (2C1), and treatment of 2C1 cells with a siRNA toward SLPI restored E-cadherin to control levels. SLPI-expressing cells showed disruption of E-cadherin/β-catenin complex and increased (P < 0.05) percentage of cells depicting nuclear β-catenin localisation. Associated to these changes, 2C1 cells showed increased Bax/Bcl-2 ratio and p21 protein levels, decreased c-Myc protein levels and decreased Cyclin D1 and Claudin-1 transcript levels. No differences in N- and P-cadherin were observed between SLPI-transfected cells and controls. Addition of rhSLPI to MCF-7 cells or stable transfection with SLPI caused a decrease (P < 0.05) in E-cadherin expression (transcript/protein) and its redistribution to the cytoplasm, as well as β-catenin re-localisation to the cell nucleus.

CONCLUSIONS

Expression of SLPI was associated to a decrease in E-cadherin expression and re-localisation of E-cadherin to the cell cytoplasm and β-catenin to the cell cytoplasm and nucleus, and had pro-apoptotic and cell cycle-arrest effects.