NF-κB In Breast Cancer Cells Research Articles

Crocin attenuates NF-κB-mediated inflammation and proliferation in breast cancer cells by down-regulating PRKCQ.

Breast cancer (BC) is the most commonly diagnosed cancer confronting women worldwide. Crocin, a glycosylated carotenoid extracted from Crocus sativus L., possesses anti-cancer and anti-inflammatory activities. This study tried to explore the influences of crocin on proliferation and inflammation of BC cells, and to investigate the possible mechanism. The protein levels of protein kinase C theta (PRKCQ) and nuclear factor kappa B (NF-κB) p-p65 and p65 were examined using western blot analysis. The potential targets of crocin were predicted using the PharmMapper database. Cell viability and proliferation were determined utilizing CCK-8 and EdU incorporation assays, respectively. Inflammation was assessed by detecting the levels of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) using RT-qPCR and ELISA. Results showed that crocin inhibited NF-κB activation and suppressed cell viability and proliferation in BC cells. Crocin caused a significant reduction of levels of TNF-α and IL-1β, suggesting that crocin suppressed inflammation in BC cells. NF-κB inhibition decreased proliferation and inflammation in BC cells. Additionally, PRKCQ was identified as a potential target of crocin according to PharmMapper database. Crocin treatment inhibited the activation of NF-κB in BC cells by reducing PRKCQ expression. Mechanistically, PRKCQ-dependent activation of NF-κB pathway reversed the effects of crocin on the proliferation and inflammation in BC cells. In conclusion, crocin inhibited NF-κB-mediated inflammation and proliferation in BC cells through reducing PRKCQ expression.

Abstract 2486: Pleiotropic anti-cancer effects of STING in estrogen receptor positive breast cancer cells

Abstract Purpose: Stimulator of interferon genes (STING) is an upstream regulator of interferon and NF-κB, the key mediators of immune and inflammatory responses associated with cancer, triggered by cytosolic DNA. Downregulation of STING in breast tumor tissues has been reported. STING elicits caspase-8-dependent cell apoptosis via NF-κB in breast cancer cells. STING agonists are considered as potent anti-cancer agents. The current study aims to assess the biological functions of STING in breast cancer progression. Experimental design: Data of mRNA expression levels and recurrence-free survival in patients with breast cancer from The Cancer Genome Atlas and Kaplan Meier-plotter databases were analyzed. Transwell assays were used to evaluate cell migrated and invaded abilities. Sphere formation was performed in stem cell-selective medium and ultra-low attachment plates. Two STING agonists, ADU-S100 and diABZI STING agonist-1 trihydrochloride, were used for in vitro studies. The molecular events were examined by Western blot analysis. Results: Data from public database showed that lower transcripts levels of STING in Her2 and luminal B breast cancer tissues than normal breast tissues. Luminal-type breast cancer cell lines harbored low STING transcripts compared with other subtypes. Importantly, breast cancer patients with low expression levels of STING was associated with worse recurrence-free survival. Results of immunoblotting indicated that breast cancer cell lines have lower STING protein expressions than normal MCF10A cells. Knockdown of STING led to aggressive phenotypes of MCF10A and BT474 cells. In contrast, overexpression of STING suppressed the abilities of migration, invasion and sphere formation of MCF7 and BT474 cells. The markers of epithelial were increased while the markers of mesenchymal and stemness were decreased by STING overexpression. STING agonist slightly suppressed cell viability of breast cancer cells but not MCF10A cells. Treatment of STING agonists reduced cell migrated ability with upregulation of E-cadherin and γ-catenin. Conclusion: These findings suggest that STING serves tumor-suppressive effects in breast cancer. Citation Format: Chun-Yu Liu, Ji-Lin Chen, Chun-Teng Huang, Pei-Yi Chu, Mei-Fang Tseng, Yu-Hsuan Lee, Wan-Lun Wang, Ling-Ming Tseng. Pleiotropic anti-cancer effects of STING in estrogen receptor positive breast cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2486.

Ursolic acid inhibits breast cancer growth by inhibiting proliferation, inducing autophagy and apoptosis, and suppressing inflammatory responses via the PI3K/AKT and NF-κB signaling pathways in vitro.

Breast cancer, which is the second leading cause of cancer-associated mortality in women worldwide, develops from breast tissue. Chemotherapy is the most commonly used therapy to treat breast cancer. However, a number of natural plant-derived products have been suggested as alternative therapies to treat different types of cancer, such as breast cancer. The aim of the present study was to determine the anti-tumor effects of ursolic acid and its effect on apoptosis and inflammation in breast cancer cells. The anti-cancer effects of ursolic acid were evaluated in vitro using flow cytometry, western blotting and reverse transcription-quantitative polymerase chain reaction. The results suggest that ursolic acid inhibits the viability of breast cancer cells by inducing autophagy and apoptosis without inducing cell death. Cellular migration assays demonstrated that ursolic acid was able to suppress the invasive ability of breast cancer cells (P<0.05). In addition, the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) pathway was downregulated following ursolic acid administration (P<0.05), leading to an upregulation of glycogen synthase kinase activity (P<0.05) and downregulation of B-cell lymphoma 2 (P<0.05), subsequently causing autophagy and apoptosis via cyclin-D1 inhibition and caspase-3 stimulation (P<0.05). Furthermore, the inflammatory response of breast cancer cells was assessed by measuring levels of nuclear factor (NF)-κB. Ursolic acid was found to downregulate NF-κB in breast cancer cells, thus inhibiting inflammation and preventing the progression of breast cancer (P<0.05). To the best of our knowledge, the present study is the first to assess the effect of ursolic acid on breast cancer cells through PI3K/AKT-regulated GSK and caspase-3 accompanied by NF-κB signaling pathways. The results of the present study regarding the potential underlying molecular mechanisms of ursolic acid may be used to develop novel therapeutic strategies for breast cancer treatment.

The SmgGDS Splice Variant SmgGDS-558 Is a Key Promoter of Tumor Growth and RhoA Signaling in Breast Cancer

Breast cancer malignancy is promoted by the small GTPases RhoA and RhoC. SmgGDS is a guanine nucleotide exchange factor that activates RhoA and RhoC in vitro. We previously reported that two splice variants of SmgGDS, SmgGDS-607, and SmgGDS-558, have different characteristics in binding and transport of small GTPases. To define the role of SmgGDS in breast cancer, we tested the expression of SmgGDS in breast tumors, and the role of each splice variant in proliferation, tumor growth, Rho activation, and NF-κB transcriptional activity in breast cancer cells. We show upregulated SmgGDS protein expression in breast cancer samples compared with normal breast tissue. In addition, Kaplan-Meier survival curves indicated that patients with high SmgGDS expression in their tumors had worse clinical outcomes. Knockdown of SmgGDS-558, but not SmgGDS-607, in breast cancer cells decreased proliferation, in vivo tumor growth, and RhoA activity. Furthermore, we found that SmgGDS promoted a Rho-dependent activation of the transcription factor NF-κB, which provides a potential mechanism to define how SmgGDS-mediated activation of RhoA promotes breast cancer. This study demonstrates that elevated SmgGDS expression in breast tumors correlates with poor survival, and that SmgGDS-558 plays a functional role in breast cancer malignancy. Taken together, these findings define SmgGDS-558 as a unique promoter of RhoA and NF-κB activity and a novel therapeutic target in breast cancer. This study defines a new mechanism to regulate the activities of RhoA and NF-κB in breast cancer cells, and identifies SmgGDS-558 as a novel promoter of breast cancer malignancy.

Abstract 5143: ErbB2 activation up-regulates glutaminase 1 expression via NF-κB pathway

Abstract Active glutamine utilization is essential for cell proliferation in many tumors, for it provides critical carbon and nitrogen sources. Glutaminolysis represents the first and rate-limiting step of glutamine utilization and is catalyzed by glutaminase. Previous studies have shown that c-Myc regulates glutaminolysis by increasing glutaminase expression in tumor cells. However, it remains unclear whether other oncogenic signaling pathways promote glutaminolysis. Breast cancer is the second most common cause of death for women in the United States and ErbB2 activation is one of the major causes of breast cancer. Using MCF10A and MCF10A-derived NeuT cells, we studied the effect of ErbB2 activation on glutaminase expression, and found that ErbB2 activation increased glutaminase 1 expression at both mRNA and protein levels. Knockdown of ErbB2 decreased glutaminase 1 expression in several human ErbB2-positive cell lines. Consistently, blocking ErbB2 signaling pathway by trastuzumab repressed glutaminase 1 expression. We further showed that in these cells, ErbB2-mediated up-regulation of glutaminase 1 was independent of c-Myc expression. In addition, we found that activation of PI3K/Akt or MAPK pathway was not sufficient to up-regulate glutaminase 1 expression. Instead, inhibition of NF-κB down-regulated glutaminase 1 expression whereas stimulation of NF-κB induced glutaminase 1 expression, suggesting a PI3K/Akt-independent activation of NF-κB signaling pathway up-regulates glutaminase 1. Finally, inhibition of glutaminase activity significantly decreased human breast cancer cell proliferation. Our data indicate that ErbB2 activation promotes glutaminase 1 expression via NF-κB in breast cancer cells, identifying another oncogenic signaling pathway which stimulates glutamine utilization. These findings may facilitate the identification of novel targets for cancer therapy. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5143. doi:1538-7445.AM2012-5143

Annexin-1 interacts with NEMO and RIP1 to constitutively activate IKK complex and NF-κB: implication in breast cancer metastasis

The molecular mechanisms underlying constitutive nuclear factor-κB (NF-κB) activation in solid tumors has not been elucidated. We show that Annexin-1 (ANXA1) is involved in this process, and suppression of ANXA1 in highly metastatic breast cancer cells impedes migration and metastasis capabilities in vitro and in vivo. ANXA1 expression correlates with NF-κB activity, suggesting that ANXA1 may be required for the constitutive activity of IκB kinase (IKK) and NF-κB in highly metatstatic breast cancer. Gel-filtration analysis demonstrated that ANXA1 co-elutes with the members of the IKK complex and NF-κB signaling pathway, and immunoprecipitation confirmed that ANXA1 can bind to and interact with IKKγ or NEMO, but not IKKα or IKKβ. Importantly, silencing of ANXA1 prevents the interaction of NEMO and RIP1, which indicates that ANXA1 is required for the recruitment of RIP1 to the IKK complex, which may be important for the activation of NF-κB. Downstream targets of NF-κB include uPA and CXCR4, which can be modulated by ANXA1 silencing. CXCR4-mediated migration of breast cancer cell lines in response to CXCL12 was significantly modulated by ANXA1, indicating its importance in the tissue-specific migration of breast cancer cells. Chromatin immunoprecipitation experiments confirmed that in ANXA1 overexpressed cells, NF-κB was recruited to CXCR4 promoter without external stimulation, indicating that ANXA1 is critical for the constitutive activation of NF-κB in breast cancer to promote metastasis. Finally, we show that ANXA1 overexpression enhances metastasis and reduces survival in an intracardiac metastasis model, while ANXA1-deficient mice crossed with MMTV-PyMT mice display significantly less metastasis than their heterozygous littermates, indicating that ANXA1 is an important gene in breast cancer metastasis. Our data reveal that ANXA1 can constitutively activate NF-κB in breast cancer cells through the interaction with the IKK complex, and suggests that modulating ANXA1 levels has therapeutic potential to suppress breast cancer metastasis.

Therapeutic intervention of experimental breast cancer bone metastasis by indole-3-carbinol in SCID-human mouse model

Several lines of experimental evidence have suggested that chemokine receptor CXCR4, a metastasis-promoting molecule, may play important roles in breast cancer bone metastasis. There is emerging evidence linking CXCR4 to matrix metalloproteinases (MMP) as well as their regulator nuclear factor-kappaB (NF-kappaB), a key transcription factor, which is known to activate metastasis-promoting molecules for many types of malignancies, including breast cancer. A recent study also showed that promoter region of CXCR4 has several NF-kappaB-binding sites, suggesting that there may be a cross-talk between CXCR4 and NF-kappaB. We have shown previously that indole-3-carbinol (I3C), a natural compound present in vegetables of the genus Brassica, can inhibit NF-kappaB in breast cancer cells. However, there are no reports in the literature showing any effect of I3C on CXCR4 expression in vitro and in vivo. We therefore examined whether I3C could inhibit bone metastasis of breast cancer by inhibiting CXCR4 and MMP-9 expression mediated via the inhibition of the NF-kappaB signaling pathway. Here, we have modified the severe combined immunodeficient (SCID)-human mouse model of experimental bone metastasis for use with the MDA-MB-231 breast cancer cell line. In this animal model, we found that I3C significantly inhibited MDA-MB-231 bone tumor growth, and our results were correlated with the down-regulation of NF-kappaB. Moreover, we found that I3C significantly inhibited the expression of multiple genes involved in the control of metastasis and invasion in vitro and in vivo, especially the expression of CXCR4 and MMP-9 along with pro-MMP-9, with concomitant decrease in Bcl-2 and increase in the proapoptotic protein Bax. From these results, we conclude that the CXCR4/NF-kappaB pathway is critical during I3C-induced inhibition of experimental breast cancer bone metastasis. These results also suggest that I3C could be a promising agent for the prevention and/or treatment of breast cancer bone metastasis in the future.

Curcumin Suppresses the Paclitaxel-Induced Nuclear Factor-κB Pathway in Breast Cancer Cells and Inhibits Lung Metastasis of Human Breast Cancer in Nude Mice

Currently, there is no effective therapy for metastatic breast cancer after surgery, radiation, and chemotherapy have been used against the primary tumor. Because curcumin suppresses nuclear factor-kappaB (NF-kappaB) activation and most chemotherapeutic agents activate NF-kappaB that mediates cell survival, proliferation, invasion, and metastasis, we hypothesized that curcumin would potentiate the effect of chemotherapy in advanced breast cancer and inhibit lung metastasis. We tested this hypothesis using paclitaxel (Taxol)-resistant breast cancer cells and a human breast cancer xenograft model. As examined by electrophoretic mobility gel shift assay, paclitaxel activated NF-kappaB in breast cancer cells and curcumin inhibited it; this inhibition was mediated through inhibition of IkappaBalpha kinase activation and IkappaBalpha phosphorylation and degradation. Curcumin also suppressed the paclitaxel-induced expression of antiapoptotic (XIAP, IAP-1, IAP-2, Bcl-2, and Bcl-xL), proliferative (cyclooxygenase 2, c-Myc, and cyclin D1), and metastatic proteins (vascular endothelial growth factor, matrix metalloproteinase-9, and intercellular adhesion molecule-1). It also enhanced apoptosis. In a human breast cancer xenograft model, dietary administration of curcumin significantly decreased the incidence of breast cancer metastasis to the lung and suppressed the expression of NF-kappaB, cyclooxygenase 2, and matrix metalloproteinase-9. Overall, our results indicate that curcumin, which is a pharmacologically safe compound, has a therapeutic potential in preventing breast cancer metastasis possibly through suppression of NF-kappaB and NF-kappaB-regulated gene products.

Normal Breast Epithelial Cells Induce Apoptosis of Breast Cancer Cells via Fas Signaling

Fas/Fas ligand (Fas L) death pathway is an important mediator of apoptosis. Deregulation of Fas pathway is reported to be involved in the immune escape of breast cancer and the resistance to anti-cancer drugs. In this study, we demonstrated that conditioned medium by normal breast epithelial cells (NBEC-CM) induced apoptosis of MCF-7 and T-47D Fas-sensitive cells but had no effect on MDA-MB-231 Fas-resistant cells. Inhibition of PI3 kinase or NF-κB by specific inhibitors or transient transfections restored the sensitivity of MDA-MB-231 cells to NBEC-induced apoptosis. Moreover, the constitutive activation of NF-κB was controlled by PI3 kinase because inhibition of PI3 kinase reduced NF-κB activity. Inducible activation of NF-κB rendered MCF-7 cells resistant to NBEC-CM- and Fas agonist antibody-triggered apoptosis. Therefore, constitutive or inducible activation of PI3 kinase and/or NF-κB in breast cancer cells rendered them resistant to NBEC-triggered apoptosis. In addition, Fas neutralizing antibody and dominant negative Fas abolished NBEC-triggered apoptosis. Western blot and confocal microscopy analysis showed an increase of membrane Fas/Fas L when cells were induced into apoptotis by NBEC-CM. Taken together, these data show that NBEC induced apoptosis in breast cancer cells via Fas signaling.