OBJECTIVE:Periodontitis is a chronic inflammatory disease characterized by destruction of periodontal connective tissues driven by dysregulated host responses. Interleukin-1β (IL-1β) plays a central role in periodontal inflammation by inducing matrix metalloproteinases (MMPs) and pro-inflammatory cytokines in gingival fibroblasts. Although Bruton's tyrosine kinase (BTK) is known to regulate inflammatory signaling in immune cells, its role in gingival fibroblasts remains unclear. This study investigated the role of BTK in IL-1β-induced inflammatory and catabolic responses in human gingival fibroblasts (HGFs). DESIGN:HGFs were stimulated with IL-1β in the presence or absence of BTK inhibitors (ibrutinib and CNX-774) or following BTK-specific siRNA transfection. Expression of MMPs and cytokines was analyzed by real-time PCR, western blotting, and ELISA. Signaling pathways were evaluated by assessing phosphorylation of TAK1 and MAPKs and activation of AP-1 and NF-κB. RESULTS:IL-1β markedly increased the expression and secretion of MMP-1 and MMP-3, as well as TNF-α, IL-6, and IL-8 in HGFs. Pharmacological inhibition or genetic silencing of BTK significantly attenuated these responses without affecting cell viability. Mechanistically, BTK inhibition suppressed IL-1β-induced phosphorylation of TAK1, ERK, and JNK and reduced AP-1 activation. CONCLUSIONS:These findings identify BTK as a key regulator of IL-1β-induced inflammatory and matrix-degradative responses via the TAK1-MAPK-AP-1 signaling axis. Targeting BTK may represent a potential therapeutic strategy for periodontitis.

[This corrects the article DOI: 10.3892/ol.2022.13474.].

Cannabidiol (CBD), a nonpsychoactive compound from Cannabis, has various bioactive functions in humans and animals. Evidence suggests that CBD promotes muscle injury recovery in athletes, but whether and how CBD improves endurance performance remains unclear. Here we investigated the effects of CBD treatment on exercise performance in mice and assessed whether this effect involves the gut microbiome. CBD administration significantly increased treadmill running performance in mice, accompanied by an increase in oxidative myofiber composition. CBD also increased mitochondrial biogenesis and the expression of associated genes such as PGC-1α, phosphorylated CREB and AMPK in muscle tissue. Interestingly, CBD altered the composition of the gut microbiome, and antibiotic treatment reduced the muscle endurance-enhancing effects of CBD and mitochondrial biogenesis. We isolated Bifidobacterium animalis, a microbe increased by CBD administration, and named it KBP-1. Treatment with B. animalis KBP-1 in mice resulted in improved running performance. Whole-genome analysis revealed that B. animalis KBP-1 presented high expression of genes involved in branched-chain amino acid biosynthesis, expression of branched-chain amino acid release pumps and metabolism of lactic acid. In summary, our study identified CBD and B. animalis KBP-1 as potential endurance exercise-promoting agents. This study explores how cannabidiol (CBD), a compound from the Cannabis sativa plant, affects exercise performance and muscle function. The researchers wanted to see if CBD could improve endurance by changing gut bacteria. They found that CBD improved endurance and increased the presence of certain gut bacteria, including Bifidobacterium animalis, that may help muscles use energy more efficiently. The study involved treating mice with either CBD or B. animalis for 4 weeks and measuring their running ability on a treadmill. The researchers examined changes in muscle fibers and gut bacteria composition. They discovered that CBD and B. animalis increased oxidative muscle fibers, which benefit endurance performance. The results suggest that CBD enhances exercise performance by promoting beneficial gut bacteria and improving muscle energy use. The researchers conclude that both CBD and B. animalis could be used to boost endurance.

Atopic dermatitis (AD) is a chronic dermatological disorder characterized by intense pruritus and eczematous lesions. Repeated topical application of 2,4-dinitrofluorobenzene (DNFB) in NC/Nga mice produces AD-like clinical symptoms that closely resemble human AD. N-acetyl-L-alanine (L-NAA), a derivative of L-Alanine, has unknown biological and physiological effects on cutaneous tissue. In this study, we investigated whether L-NAA modifies AD-like symptoms elicited by ongoing DNFB exposure in NC/Nga mice. Topical administration of L-NAA markedly attenuated the development of AD-like cutaneous lesions triggered by DNFB. L-NAA treatment further suppressed DNFB-induced infiltration of eosinophils and mast cells and prevented the increase of serum IgE resulting from DNFB application. L-NAA treatment decreased DNFB-stimulated expression of IL-4, a Th2-associated cytokine, but increased IFN-γ expression, indicative of Th1 activity, within the skin lesions. In addition, L-NAA prevented the DNFB-driven upregulation of GATA3, a central regulator of Th2 lineage differentiation, in CD4＋ cells, with no effect on T-bet, the principal regulator of Th1 cells. These findings indicate that L-NAA can limit Th2 differentiation in the AD mouse model. Therefore, L-NAA may serve as a promising therapeutic and immunomodulatory compound against AD. [BMB Reports 2025; 58(10): 437-443].

Advancements in audio-visual representation learning have showcased its effectiveness in acquiring rich and comprehensive representations by leveraging both auditory and visual modalities. Recent works have attempted to improve performance using contrastive learning or masked modeling techniques. However, the effort to maximize the impact of data augmentations for learning semantically rich representation has remained relatively narrow. Without a proper strategy for utilizing data augmentation, the model can be adversely affected or fail to achieve sufficient performance gains. To address this limitation, we present EquiAV, a novel framework that integrates single-modal equivariant contrastive learning with audio-visual contrastive learning. In the proposed framework, audio-visual correspondence and rich modality-specific representations are learned in separate latent spaces. In particular, augmentation-related and modality-specific information is learned in the intra-modal latent space by making the representations equivariant to data augmentation. Extensive ablation studies verify that our framework is the most suitable architecture for maximizing the benefits of the augmentation while ensuring model robustness to strong augmentation. EquiAV outperforms the existing audio-visual self-supervised pre-training methods on audio-visual event classification and zero-shot audio-visual retrieval tasks.

Recent advancements in self-supervised audio-visual representation learning have demonstrated its potential to capture rich and comprehensive representations. However, despite the advantages of data augmentation verified in many learning methods, audio-visual learning has struggled to fully harness these benefits, as augmentations can easily disrupt the correspondence between input pairs. To address this limitation, we introduce EquiAV, a novel framework that leverages equivariance for audio-visual contrastive learning. Our approach begins with extending equivariance to audio-visual learning, facilitated by a shared attention-based transformation predictor. It enables the aggregation of features from diverse augmentations into a representative embedding, providing robust supervision. Notably, this is achieved with minimal computational overhead. Extensive ablation studies and qualitative results verify the effectiveness of our method. EquiAV outperforms previous works across various audio-visual benchmarks.

In recent years, advancements in representation learning and language models have propelled Automated Captioning (AC) to new heights, enabling the generation of human-level descriptions. Leveraging these advancements, we propose AVCap, an Audio-Visual Captioning framework, a simple yet powerful baseline approach applicable to audio-visual captioning. AVCap utilizes audio-visual features as text tokens, which has many advantages not only in performance but also in the extensibility and scalability of the model. AVCap is designed around three pivotal dimensions: the exploration of optimal audio-visual encoder architectures, the adaptation of pre-trained models according to the characteristics of generated text, and the investigation into the efficacy of modality fusion in cap- tioning. Our method outperforms existing audio-visual captioning methods across all metrics and the code is available on https://github.com/JongSuk1/AVCap.

In general, when treating cancer patients, various anticancer drugs are used in combination to enhance the anticancer effect. However, most drugs exhibit side effects. Neurotoxicity, one of the side effects commonly accompanied, greatly affects the quality of life and also reduces compliance with treatment. Calcium signal transduction, which occupies a key position in cell signal transduction, has been found to be involved in various mechanisms including proliferation, differentiation, and death of cells, beyond the existing research direction that focuses on channels. To identify the mechanisms of calcium signal regulation that can reduce chemotherapy induced peripheral neuropathy (CIPN) while maintaining anticancer functions of drugs, we study with the two drugs frequently used in non-Hodgkin lymphoma and multiple myeloma, borteozomib (BTZ) and vincristine (VIN), whose main side effects are neurotoxicity. We used the human neuroblastoma cell line, SH-SY5Y cells, and performed MTT assay after treating them with N-Acetylcysteine ​​(NAC), an antioxidant, to determine whether the reduction in cell viability by BTZ and VIN was due to the increase in ROS. When BTZ and VIN were treated with NAC, cytotoxicity by BTZ was significantly reduced and cell viability decreased by VIN was significantly increased. From these results, we found that ROS are involved in BTZ and VIN -induced apoptosis. In addition, we performed MTT assay using calcium inhibitors to investigate whether intracellular calcium signaling is involved in BTZ and VIN-induced apoptosis, and 8-Br-cADPR, Ned-19, Xestospongin C, and Heparin were used as calcium inhibitors. To confirm that the cell viability reduced by BTZ and VIN is recovered by calcium inhibitors, BTZ and VIN were treated together with calcium inhibitors, respectively. Cell viability was found to increase significantly. These results suggest that intracellular calcium signaling is involved in cell death induced by BTZ and VIN. The increase in [ca2+]i in the cytoplasm when treated with BTZ and VIN was measured using a fluorescence spectrophotometer. It was shown that the treatment with BTZ and VIN increased the calcium concentration in the cytoplasm within 1 minute. To confirm that the concentration of intracellular calcium was reduced by the calcium inhibitor, BTZ and calcium inhibitor were treated together, and it was confirmed that the intracellular calcium concentration increased by BTZ was decreased in a concentration-dependent manner at 2uM and 3uM of the calcium inhibitor. In conclusion, this experiment suggests that intracellular calcium signaling is involved in the BTZ and VIN’s reduction of neuronal cell viability (CIPN) in multiple myeloma and non-Hodgkin lymphoma. This research was supported by NRF 2021R1A2C1091322 (J.-S.Kim) and 2021R1F1A1064120 (J. Park). Citation Format: Jinny Park, Jong-Suk Kim, Kwang-Hyun Park. Study on Ca 2+-mediated regulation mechanisms on chemotherapy-induced peripheral neuropathy in multiple myeloma and non-Hodgkin lymphoma. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4908.

Fisetin is a flavonoid found in plants and has been reported to be effective in various human diseases. However, the effective mechanisms of ultraviolet-A (UVA)-mediated skin damage are not yet clear. In this study, we investigated the protective mechanisms of fisetin regarding UVA-induced human dermal fibroblasts (HDFs) and human epidermal keratinocytes (HEKs) damages. Fisetin showed a cytoprotective effect against UVA irradiation and suppressed matrix metalloproteinases (MMPs), MMP-1, and MMP-3 expression. In addition, fisetin was rescued, which decreased mRNA levels of pro-inflammatory cytokines, reactive oxygen species production, and the downregulation of MAPK/AP-1 related protein and NADPH oxidase (NOX) mRNA levels. Furthermore, UVA-induced MMP-1 and MMP-3 were effectively inhibited by siRNAs to NOX 1 to 5 in HDFs and HEKs. These results indicate that fisetin suppresses UVA-induced damage through the NOX/ROS/MAPK pathway in HDFs and HEKs.

In this study, we aimed to develop natural and/or functional materials with antioxidant and anti-inflammatory effects. We obtained extracts from natural plants through an oil and hot-water extraction process and prepared an extract composite of an effective unsaturated fatty acid complex (EUFOC). Furthermore, the antioxidant effect of the extract complex was evaluated, and the anti-inflammatory effect was explored by assessing its inhibitory effect on nitric oxide production through its HA-promoting effect. We conducted a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide assay to evaluate the cell viability of the EUFOC, and the results showed that EUFOC was not cytotoxic at the test concentrations. In addition, it showed no endogenous cytotoxicity in HaCaT (human keratinocyte) cells. The EUFOC showed excellent 1,1-diphenyl-2-picrylhydrazyl- and superoxide-scavenging abilities. Moreover, it exerted an inhibitory effect on NO production at concentrations that did not inhibit cell viability. The secretion of all the cytokines was increased by lipopolysaccharide (LPS) treatment; however, this was inhibited by the EUFOC in a concentration-dependent manner. In addition, hyaluronic acid content was markedly increased by the EUFOC in a dose-dependent manner. These results suggest that the EUFOC has excellent anti-inflammatory and antioxidant properties, and hence, it can be used as a functional material in various fields.

Protaetia brevitarsis (PB)-derived bioactive substances have been used as food and medicine in many Asian countries because of their antioxidant, antidiabetic, anti-cancer, and hepatoprotective properties. However, the effect of PB extracts (PBE) on osteoclast differentiation is unclear. In this study, we investigated the effect of PBE on RANKL-induced osteoclastogenesis in mouse bone marrow-derived macrophages (BMMs). To investigate the cytotoxicity of PBE, the viability of BMMs was confirmed via MTT assay. Tartrate-resistant acid phosphatase (TRAP) staining and pit assays were performed to confirm the inhibitory effect of PBE on osteoclast differentiation and bone resorption. The expression levels of osteoclast differentiation-related genes and proteins were evaluated using quantitative real-time PCR and Western blotting. PBE attenuated osteoclastogenesis in BMMs in TRAP and pit assays without cytotoxicity. The expression levels of osteoclast marker genes and proteins induced by RANKL were decreased after PBE treatment. PBE suppressed osteoclastogenesis by inhibiting the RANKL-induced activated JNK/NF-κB/PLCγ2 signaling pathway and the expression of NFATc1 and c-Fos. Collectively, these results suggest that PBE could be a potential therapeutic strategy or functional product for osteoclast-related bone disease.

Sirtuin 6 (SIRT6) regulation is involved in carcinogenesis. However, its role in breast cancer (BC) metastasis remains unclear. We investigated the effects of SIRT6 on protein kinase C activator- and cytokine-mediated cancer cell invasion and migration in MCF-7 and MDA-MB-231 cells and the association between SIRT6 and matrix metalloproteinase-9 (MMP-9) expression. To assess MMP-9 and SIRT6 expression in patients, protein levels in BC tissues were analyzed. MCF-7 and MDA-MB-231 cell viability was analyzed using MTT assays. SIRT6 was silenced in both cell lines and protein secretion, expression, and mRNA levels were analyzed. Transcription factor DNA activity was investigated using luciferase assays. Matrigel invasion assays were used to assess the effects of SIRT6 in both cell lines. SIRT6 and MMP-9 expression in cancer tissues was significantly higher than in paired normal breast tissues. 12-O-tetradecanoylphorbol-13-acetate (TPA) or tumor necrosis factor-α (TNF-α) increased MMP-9 expression and cell invasion and migration, but SIRT6 knockdown abolished these effects. SIRT6 overexpression additively increased TPA- and TNF-α-induced MMP-9 expression. SIRT6 knockdown suppressed the mitogen-activated protein kinase (MAPK) signaling pathway and thus TPA- and TNF-α-induced MMP-9 expression. SIRT6 silencing suppressed TPA- and TNF-α-induced nuclear factor-κB (NF-κB) and activator protein-1 (AP-1) expressions in both cell lines, and treatment with MAPK, NF-κB, and AP-1 inhibitors reduced MMP-9 expression. The anti-invasive effects of SIRT6 in BC cells might be mediated by suppression of MAPK phosphorylation and reduction in NF-κB and AP-1 DNA activities, leading to MMP-9 downregulation, suggesting that SIRT6 modulation has the potential to target BC metastasis.

Aurora kinase is a family of serine/threonine kinases intimately associated with mitotic progression and the development of human cancers. Studies have shown that aurora kinases are important for the protein kinase C (PKC)-induced invasion of colon cancer cells. Recent studies have shown that aurora kinase A promotes distant metastasis by inducing epithelial-to-mesenchymal transition (EMT) in colon cancer cells. However, the role of aurora kinase A in colon cancer metastasis remains unclear. In this study, we investigated the effects of aurora kinase A on PKC-induced cell invasion, migration, and EMT in human SW480 colon cancer cells. Treatment with 12-O-tetradecanoylphorbol- 13-acetate (TPA) changed the expression levels of EMT markers, increasing α-SMA, vimentin, and MMP-9 expression and decreasing E-cadherin expression, with changes in cell morphology. TPA treatment induced EMT in a PKC-dependent manner. Moreover, the inhibition of aurora kinase A by siRNAs and inhibitors (reversine and VX-680) suppressed TPA-induced cell invasion, migration, and EMT in SW480 human colon cells. Inhibition of aurora kinase A blocked TPA-induced vimentin and MMP-9 expression, and decreased E-cadherin expression. Furthermore, the knockdown of aurora kinase A decreased the transcriptional activity of NF-κB and AP-1 in PKC-stimulated SW480 cells. These findings indicate that aurora kinase A induces migration and invasion by inducing EMT in SW480 colon cancer cells. To the best of our knowledge, this is the first study that showed aurora kinase A is a key molecule in PKC-induced metastasis in colon cancer cells. [BMB Reports 2022;55(2): 87-91].

The mTOR pathway is a crucial biological regulatory mechanism of cell growth, proliferation and cell death, and its inhibitors were new candidates of anticancer drugs through regulation of energy balance and metabolism. In the present study, whether brazilin and mTOR inhibitor (Torin1) exerts anti-cancer effects was evaluated and the mechanism of its regulation in colorectal cancer cells investigated. Brazilin showed dose- and time-dependent cytotoxicity of colorectal cancer cells (SW480 cells) through apoptosis pathways such as Bcl-2, Bax, as well as cleavage of caspase 3, caspase 9, and PARP1. In addition, brazilin reduced mammalian target of rapamycin (mTOR) phosphorylation in a dose- and time-dependent manner, and the mTOR inhibitor torin 1 blocked this phosphorylation. Brazilin also decreased heme oxygenase-1 (HO-1) expression in a dose- and time-dependent manner; however, hemin, a specific HO-1 substrate, markedly increased HO-1 expression. Torin 1 reduced hemin-induced HO-1 expression and increased colorectal cell death in a dose-dependent manner in the presence and absence of hemin. Moreover, nuclear factor erythroid 2–related factor 2 (Nrf2) translocation into nucleus fraction was crucial role in brazilin-mediated apoptosis of colorectal cancer cells. These results showed that brazilin and torin1 might regulate the mTOR signaling pathway by decreasing mTOR phosphorylation. Furthermore, mTOR signaling was associated with brazilin-regulated HO-1 expression, which induced apoptosis in colorectal cancer cells. These results suggest that synthetic and/or natural mTOR inhibitors were useful candidate for treatment of colorectal cancer cells.

Peroxisome proliferator-activated receptor-γ (PPAR-γ) acts as a key factor in breast cancer metastasis. Notably, PPAR-γ can inhibit metalloproteinase (MMP), which is involved in cancer metastasis. Our previous study revealed that PPAR-γ was related to breast cancer metastasis. The present study aimed to investigate whether the PPAR-γ ligand 2-cyano-3,12-dioxooleana-1,9-dien-28-oic acid (CDDO) mediated suppression of cell invasion and reduced the expression of MMP-9 in breast cancer cells. The results indicated that CDDO reduced MMP-9 expression, cell migration and invasion of breast cancer cells by inhibiting TPA-induced phosphorylation of mitogen-activated protein kinases, and downregulating the activities of activator protein-1 and nuclear factor κB. Notably, knock-out of PPAR-γ by small interfering RNA in MCF-7 cells revealed that TPA-induced MMP-9 expression occurred through a PPAR-γ-independent pathway. These data indicated that the downregulatory effect of CDDO on MMP-9 expression was affected by a mechanism independent of PPAR-γ. In conclusion, the findings of the present study suggested that CDDO may act as a key agent in the regulation of breast cancer metastasis, suggesting CDDO as a new targeted therapy for breast cancer.

Acute promyelocytic leukemia (APL) represents a group of haematological malignancies characterized by blocked differentiation. Cell differentiation has been as a strong target of treatment of APL. Peroxisome proliferator-activated receptors gamma (PPAR-γ) play an important role in the differentiation of APL cell lines. Previous study has shown that PPAR-γ ligands induce neutrophil/ monocytic differentiation in human acute promyelocytic leukemia HL-60 cells. It has recently been shown that the novel synthetic triterpenoid 2-cyano-3,12-dioxooleana-1,9-dien-28-oic acid (CDDO) induces differentiation in leukemia HL-60 cells. In this study we established a CDDO-induced differentiation model for the treatment of APL. We evaluated for the surface antigen expression associated with myeloid maturation, CD11b and CD14 by flow cytometric analysis and RT-PCR. We demonstrated that CD11b and CD14 increased as CDDO -induced differentiation. In addition, CDDO induced a HL-60 differentiation through the regulation of PTEN expression. PTEN also has various cellular function such as cell differentiation. PPAR-γ could synergistically up-regulate PTEN in human leukemia cells and consequently stimulate the differentiation of these cells We confirmed that suppression of PTEN with the inhibitor (SF1760) caused reduction of differentiated HL-60 cells. Our results suggest PPAR-γ an important role in controlling the differentiation of leukemia cells via the regulation of PTEN. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Pre-training vision-language models with contrastive objectives has shown promising results that are both scalable to large uncurated datasets and transferable to many downstream applications. Some following works have targeted to improve data efficiency by adding self-supervision terms, but inter-domain (image-text) contrastive loss and intra-domain (image-image) contrastive loss are defined on individual spaces in those works, so many feasible combinations of supervision are overlooked. To overcome this issue, we propose UniCLIP, a Unified framework for Contrastive Language-Image Pre-training. UniCLIP integrates the contrastive loss of both inter-domain pairs and intra-domain pairs into a single universal space. The discrepancies that occur when integrating contrastive loss between different domains are resolved by the three key components of UniCLIP: (1) augmentation-aware feature embedding, (2) MP-NCE loss, and (3) domain dependent similarity measure. UniCLIP outperforms previous vision-language pre-training methods on various single- and multi-modality downstream tasks. In our experiments, we show that each component that comprises UniCLIP contributes well to the final performance.

Matriptases, members of the type II transmembrane serine protease family, are cell surface proteolytic enzymes that mediate tumor invasion and metastasis. Matriptase is highly expressed in breast cancer and is associated with poor patient outcome. However, the cellular mechanism by which matriptase mediates breast cancer invasion remains unknown. The present study aimed to determine the role of matriptase in the protein kinase C (PKC)-mediated metastasis of MCF-7 human breast cancer cells. Matriptase small interfering RNA-mediated knockdown significantly attenuated the 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced invasiveness and migration of MCF-7 cells, and inhibited the activation of phospholipase C γ2 (PLCγ2)/PKC/MAPK signaling pathways. Matriptase-knockdown also suppressed the expression of MMP-9 and inhibited the activation of NF-κB/activator protein-1 in MCF-7 cells. Additionally, GB83 [an inhibitor of protease-activated receptor-2 (PAR-2)] inhibited PKC-mediated MMP-9 expression and metastatic ability in MCF-7 cells. Furthermore, downregulation of matriptase suppressed TPA-induced MMP-9 expression and invasiveness via PAR-2/PLCγ2/PKC/MAPK activation. These findings shed light on the mechanism underlying the role of matriptase in MCF-7 cell invasion and migration ability, and suggest that matriptase modulation could be a promising therapeutic strategy for preventing breast cancer metastasis.

Triptolide is a diterpenoid epoxide that is endogenously produced by the thunder god vine, Tripterygium wilfordii Hook F. Triptolide has demonstrated a variety of biological activities, including anticancer activities, in previous studies. Invasion and metastasis are the leading causes of mortality for patients with breast cancer, and the increased expression of matrix metalloproteinase-9 (MMP-9) has been shown to be associated with breast cancer invasion. Therefore, the aim of the present study was to investigate the effect of triptolide on 12-O-tetradecanoyl phorbol-13-acetate (TPA)-induced cell invasion and MMP-9 expression in breast cancer cells. The expression of signal molecules was examined by western blotting, zymography and quantitative polymerase chain reaction; an electrophoretic mobility gel shift assay was also used, and cell invasiveness was measured by an in vitro Matrigel invasion assay. The MCF-7 human breast cancer cell line was treated with triptolide at the highest concentrations at which no marked cytotoxicity was evident. The results demonstrated that triptolide decreased the expression of MMP-9 through inhibition of the TPA-induced phosphorylation of extracellular signal-regulated kinase (ERK) and the downregulation of nuclear factor-κB (NF-κB) and activator protein-1 (AP-1) activity. In addition, a Transwell assay revealed that triptolide reduced the ability of MCF-7 cells to invade Matrigel. These data demonstrate that the anti-invasive effect of triptolide is associated with the inhibition of ERK signaling and NF-κB and AP-1 activation, and suggest that triptolide may be a promising drug for breast cancer.

Bruton's agammaglobulinemia tyrosine kinase (BTK) is an important cytoplasmic tyrosine kinase involved in B-lymphocyte development, differentiation, and signaling. Activated protein kinase C (PKC), in turn, induces the activation of mitogen-activated protein kinase (MAPK) signaling, which promotes cell proliferation, viability, apoptosis, and metastasis. This effect is associated with nuclear factor-κB (NF-κB) activation, suggesting an anti-metastatic effect of BTK inhibitors on MCF-7 cells that leads to the downregulation of matrix metalloproteinase (MMP)-9 expression. However, the effect of BTK on breast cancer metastasis is unknown. In this study, the anti-metastatic activity of BTK inhibitors was examined in MCF-7 cells focusing on MMP-9 expression in 12-O-tetradecanoylphorbol-13-acetate (TPA)-stimulated MCF-7 cells. The expression and activity of MMP-9 in MCF-7 cells were investigated using quantitative polymerase chain reaction analysis, western blotting, and zymography. Cell invasion and migration were investigated using the Matrigel invasion and cell migration assays. BTK inhibitors [ibrutinib (10 µM), CNX-774 (10 µM)] significantly attenuated TPA-induced cell invasion and migration in MCF-7 cells and inhibited the activation of the phospholipase Cγ2/PKCβ signaling pathways. In addition, small interfering RNA specific for BTK suppressed MMP-9 expression and cell metastasis. Collectively, results of the present study indicated that BTK suppressed TPA-induced MMP-9 expression and cell invasion/migration by activating the MAPK or IκB kinase/NF-κB/activator protein-1 pathway. The results clarify the mechanism of action of BTK in cancer cell metastasis by regulating MMP-9 expression in MCF-7 cells.