Suppresses Breast Cancer Cell Research Articles

A Potential Combination of Targeting HSP90 and mTOR in Breast Cancer Cell Growth, Migration, and Invasion Through Inhibiting AKT Phosphorylation and F-actin Organization.

Breast cancer is the most prevalent form of cancer among women worldwide, with a high mortality rate. While the most common cause of breast cancer death is metastasis, there is currently no potential treatment for patients at the metastatic stage. The present study investigated the potential of using a combination of HSP90 and mTOR inhibitor in the treatment of breast cancer cell growth, migration, and invasion. Gene Expression Profiling Interactive Analysis (GEPIA) was used to investigate the gene expression profiles. Western blot analysis and fluorescence staining were used for protein expression and localization, respectively. MTT, wound healing, and transwell invasion assays were used for cell proliferation, migration, and invasion, respectively. GEPIA demonstrated that HSP90 expression was significantly higher in breast invasive carcinoma compared to other tumor types, and this expression correlated with mTOR levels. Treatment with 17-AAG, an HSP90 inhibitor, and Torkinib, an mTORC1/2 inhibitor, significantly inhibited cell proliferation. Moreover, combination treatment led to down-regulation of AKT. Morphological changes revealed a reduction in F-actin intensity, a marked reduction of YAP, with interference in nuclear localization. Targeting HSP90 and mTOR has the potential to suppress breast cancer cell growth and progression by disrupting AKT signaling and inhibiting F-actin polymerization. This combination treatment may hold promise as a therapeutic strategy for breast cancer treatment that ameliorates adverse effects of a single treatment.

Corrigendum: A small molecule inhibitor of Notch1 modulates stemness and suppresses breast cancer cell growth

Corrigendum: A small molecule inhibitor of Notch1 modulates stemness and suppresses breast cancer cell growth

Cryoprotective isoliquiritigenin-zein phosphatidylcholine nanoparticles inhibits breast cancer-bone metastasis by targeting JAK-STAT signaling pathways

Breast cancer (BC) is the most common cancer in women and is known for its tendency to spread to the bones, causing significant health issues and mortality. In this study, we aimed to investigate whether cryoprotective isoliquiritigenin-zein phosphatidylcholine nanoparticles (ISL@ZLH NPs) could inhibit BC-induced bone destruction and tumor metastasis in both in vitro and animal models. To evaluate the potential of ISL@ZLH NPs, we conducted various experiments. First, we assessed cell viability, colony formation, transwell migration, and wound healing assays to determine the impact of ISL@ZLH NPs on BC cell behavior. Western blotting, TRAP staining and ALP activity were performed to examine the effects of ISL@ZLH NPs on osteoclast formation induced by MDA-MB-231 cell-conditioned medium and RANKL treated RAW 264.7 cells. Furthermore, we assessed the therapeutic impact of ISL@ZLH NPs on tumor-induced bone destruction using a mouse model of BC bone metastasis. Treatment with ISL@ZLH NPs effectively suppressed BC cell proliferation, colony formation, and motility, reducing their ability to metastasize. ISL@ZLH NPs significantly inhibited osteoclast formation and the expression of factors associated with bone destruction in BC cells. Additionally, ISL@ZLH NPs suppressed JAK-STAT signaling in RAW264.7 cells. In the BCBM mouse model, ISL@ZLH NPs led to a significant reduction in osteolytic bone lesions compared to the control group. Histological analysis and TRAP staining confirmed that ISL@ZLH NPs preserved the integrity of bone structure, preventing invasive metastasis by confining tumor growth to the bone marrow cavity. Furthermore, ISL@ZLH NPs effectively suppressed tumor-induced osteoclastogenesis, a key process in BC-related bone destruction. Our findings demonstrate that ISL@ZLH NPs have the potential to inhibit BC-induced bone destruction and tumor metastasis by targeting JAK-STAT signaling pathways and suppressing tumor-induced osteoclastogenesis. These results underscore the therapeutic promise of ISL@ZLH NPs in managing BC metastasis to the bones.

A CARM1 Inhibitor Potently Suppresses Breast Cancer Both In Vitro and In Vivo.

CARM1, belonging to the protein arginine methyltransferase (PRMT) family, is intricately associated with the progression of cancer and is viewed as a promising target for both cancer diagnosis and therapy. However, the number of specific and potent CARM1 inhibitors is limited. We herein discovered a CARM1 inhibitor, iCARM1, that showed better specificity and activity toward CARM1 compared to the known CARM1 inhibitors, EZM2302 and TP-064. Similar to CARM1 knockdown, iCARM1 suppressed the expression of oncogenic estrogen/ERα-target genes, whereas activated type I interferon (IFN) and IFN-induced genes (ISGs) in breast cancer cells. Consequently, iCARM1 potently suppressed breast cancer cell growth both in vitro and in vivo. The combination of iCARM1 with either endocrine therapy drugs or etoposide demonstrated synergistic effects in inhibiting the growth of breast tumors. In summary, targeting CARM1 by iCARM1 effectively suppresses breast tumor growth, offering a promising therapeutic approach for managing breast cancers in clinical settings.

MEIS2 suppresses breast cancer development by downregulating IL10.

Breast cancer (BC) is the most commonly diagnosed female cancer. Homeobox protein MEIS2, a key transcription factor, is involved in the regulation of many developmental and cellular processes. However, the role of MEIS2 in the development of breast cancer is still unclear. We aimed to examine the role of myeloid ecotropic insertion site (MEIS2) in breast cancer and the association of MEIS2 with breast cancer clinical stages and pathological grades. We revealed the underlying mechanism by which MEIS2 affected breast cancer cell growth and tumor development. Using human BC cell lines, clinical samples and animal xenograft model, we reveal that MEIS2 functions as a tumor suppressor in breast cancer. The expression of MEIS2 is inversely correlated with BC clinical stages and pathological grades. MEIS2 knockdown (MEIS2-KD) promotes while MEIS2 overexpression suppresses breast cancer cell proliferation and tumor development in vitro and in animal xenograft models, respectively. To determine the biological function of MEIS2, we screen the expression of a group of MEIS2 potential targeting genes in stable-established cell lines. Results show that the knockdown of MEIS2 in breast cancer cells up-regulates the IL10 expression, but MEIS2 overexpression opposed the effect on IL10 expression. Furthermore, the suppressive role of MEIS2 in breast cancer cell proliferation is associated with the IL10 expression and myeloid cells infiltration. Our study demonstrates that the tumor suppressor of MEIS2 in breast cancer progression is partially via down regulating the expression of IL10 and promoting myeloid cells infiltration. Targeting MEIS2 would be a potentially therapeutic avenue for BC.

Inhibitory effects of medium-chain fatty acids on the proliferation of human breast cancer cells via suppression of Akt/mTOR pathway and modulating the Bcl-2 family protein.

Medium-chain fatty acids (MCFAs) have 6-12 carbon atoms and are instantly absorbed into the bloodstream before traveling to the portal vein and the liver, where they are immediately used for energy and may have antitumor effects. Its role in breast cancer is poorly understood. To investigate the apoptosis-inducing effect of MCFAs in breast cancer cells, cell viability assay, colony formation assay, cell migration assay, cell invasion assay, nuclear morphology, cell cycle assay, intracellular reactive oxygen species (ROS), matrix metalloproteinase (MMP), apoptosis, RT-qPCR analysis, and Western blot analysis were performed. In the present study, MCFA treatments reduced proliferative capability, increased ROS level, increased the depletion of MMP, induced G0/G1 and S phase cell cycle arrest, and late apoptosis of breast cancer cells in an effective concentration. Besides, MCFA treatment contributed to the upregulation of proapoptotic protein (BAK) and caspase-3, and the downregulation of antiapoptotic protein (Bcl-2). Mechanistically, phosphorylation levels of EGFR, Akt, and mTOR were significantly reduced in breast cancer cells treated with MCFAs. However, no significant changes in apoptosis and signaling-related proteins were observed in lauric acid-treated ER-positive cancer cells. Our findings suggested that MCFAs suppressed breast cancer cell proliferation by modulating the PI3K/Akt/mTOR signaling pathway. MCFAs may be a promising therapeutic drug for treating breast cancer.

EEF1A2 promotes PTEN-GSK3β-SCF complex-dependent degradation of Aurora kinase A and is inactivated in breast cancer.

The translation elongation factor eEF1A promotes protein synthesis. Its methylation by METTL13 increases its activity, supporting tumor growth. However, in some cancers, a high abundance of eEF1A isoforms is associated with a good prognosis. Here, we found that eEF1A2 exhibited oncogenic or tumor-suppressor functions depending on its interaction with METTL13 or the phosphatase PTEN, respectively. METTL13 and PTEN competed for interaction with eEF1A2 in the same structural domain. PTEN-bound eEF1A2 promoted the ubiquitination and degradation of the mitosis-promoting Aurora kinase A in the S and G2 phases of the cell cycle. eEF1A2 bridged the interactions between the SKP1-CUL1-FBXW7 (SCF) ubiquitin ligase complex, the kinase GSK3β, and Aurora-A, thereby facilitating the phosphorylation of Aurora-A in a degron site that was recognized by FBXW7. Genetic ablation of Eef1a2 or Pten in mice resulted in a greater abundance of Aurora-A and increased cell cycling in mammary tumors, which was corroborated in breast cancer tissues from patients. Reactivating this pathway using fimepinostat, which relieves inhibitory signaling directed at PTEN and increases FBXW7 expression, combined with inhibiting Aurora-A with alisertib, suppressed breast cancer cell proliferation in culture and tumor growth in vivo. The findings demonstrate a therapeutically exploitable, tumor-suppressive role for eEF1A2 in breast cancer.

Phloretin Inhibits the Proliferation of Breast Cancer Cells Through the Down-regulation of Estrogen Receptor α.

Phloretin is a natural flavonoid compound found in some plants, such as apples and pears, as well as in the bark of apple trees. Phloretin has been shown to have inhibitory effects on glucose transporters in cells and can potentially inhibit the growth of cancer cells. However, the mechanism by which phloretin regulates the expression of estrogen receptor alpha (ERα), a key transcription factor in breast cancer, is still unclear. This study investigated how phloretin affects the growth of ERα positive human breast cancer cells. The growth of breast cancer cell lines, including MCF7 and T47D, was examined using cell proliferation and colony formation assays. Western blotting and semi-quantitative RT-PCR were used to examine protein and mRNA levels, respectively. Localization of cellular proteins was analyzed using subcellular fractionation. Transient transfection and reported gene assays were used to elucidate the impact of phloretin on cell proliferation and ERα transactivation. Phloretin decreased ERα expression at the mRNA and protein levels in MCF7 and T47D cells. It also inhibited the binding of ERα to the estrogen response element present in the promoter of target genes. Moreover, treatment with phloretin inhibited the expression of cyclin D1 and breast cancer marker gene pS2, which are known ERα target genes. Consequently, it inhibited the growth of ERα-positive human breast cancer cells. Furthermore, inhibition of breast cancer growth by phloretin was found to be mediated through both the ERα and ERK1/ERK2 pathways. Phloretin, a dihydrochalcone extracted from natural sources, exhibits the ability to regulate ERα function and suppress breast cancer cell proliferation.

Pan-cancer Analysis Combined with Experiments Deciphers PHB Regulation for Breast Cancer Cell Survival and Predicts Biomarker Function

Background:: Breast carcinoma has become the leading fatal disease among women. The location of prohibitin in the chromosome is close to the breast cancer susceptibility gene 1 (BRCA1). Accumulated research reported that prohibitin could interact with a variety of transcription factors and cell cycle-regulating proteins. Objective:: This present study aims to comprehensively explore and reveal the biological functions of prohibitin on breast cancer via The Cancer Genome Atlas (TCGA) and validation experiment in vitro. Methods:: Exploring the expression level of prohibitin across 27 tumors based on the TGGA database by bioinformatic methods and its relationship with tumor immune infiltration. Furthermore, we thus analyzed the biological roles of prohibitin on human breast cancer cell line MCF- 7 with pEGFP-prohibitin overexpression plasmid by western blotting and transwell-assay. Results:: Firstly, we found prohibitin is overexpressed in most tumors based on The Cancer Genome Atlas database, and the negative relationships between prohibitin and tumors infiltrating lymphocytes including B lymphocyte, CD4 T lymphocyte, CD8 T lymphocyte, Neutrophil, Macrophage and Dendritic, and its significant correlation with the prognosis of human cancer. In vitro, expression not only inhibited cell viability and invasive abilities but also increased the apoptosis percentage of cells with a decreased percentage of the S phase and an increased G2 phase. The reduction of Bcl-2 was observed when prohibitin was upregulated, although the expression of E2F-1 did not change. Conclusion:: Although prohibitin is over-expressed in various cancer types, it functions as an important tumor suppressor that may suppress breast cancer cell proliferation and the invasive ability of MCF-7 by influencing its DNA synthesis and promoting cell apoptosis. All these may be likely associated with P53, erbB-2, and Bcl-2.

Oleuropein and its hydrolysate from extra virgin olive oil inhibit breast cancer cells proliferation interfering with the PI3K-AKT signal pathway

Naturally existing polyphenols in virgin olive oil possess significative biological activities and are potential nutraceutical therapeutic for breast cancer. In the present study, we investigated the anti-breast cancer activity of oleuropein and its hydrolysates, and further explored their molecular mechanisms. A similar cellular viability was observed in MCF-7 and MDA-MB-231 cells both treated with oleocanthal (3 μg/mL), hydroxytyrosol (30 μg/mL) and oleuropein (200 μg/mL) showed the same cellular viability, indicating oleocanthal structure may be the main structural component part of the physiological activity of oleuropein. Results showed that olive polyphenols produced reactive oxygen species and suppressed breast cancer cells. For flow cytometry analysis, the three polyphenols impacted the MCF-7 cell and MDA-MB-231 cycle, stagnated in the G1 phase and S phase, respectively, via reducing Cyclin D protein expression and promoting cell apoptosis. The pro-apoptosis, anti-proliferation capacity and delaying cell cycle of the three olive oil polyphenols could be achieved through the PI3K-AKT signaling pathway, mainly inhibited phosphorylation of AKT, PI3K protein.

Targeting PRMT1-mediated SRSF1 methylation to suppress oncogenic exon inclusion events and breast tumorigenesis

PRMT1 plays a vital role in breast tumorigenesis; however, the underlying molecular mechanisms remain incompletely understood. Herein, we show that PRMT1 plays a critical role in RNA alternative splicing, with a preference for exon inclusion. PRMT1 methylome profiling identifies that PRMT1 methylates the splicing factor SRSF1, which is critical for SRSF1 phosphorylation, SRSF1 binding with RNA, and exon inclusion. In breast tumors, PRMT1 overexpression is associated with increased SRSF1 arginine methylation and aberrant exon inclusion, which are critical for breast cancer cell growth. In addition, we identify a selective PRMT1 inhibitor, iPRMT1, which potently inhibits PRMT1-mediated SRSF1 methylation, exon inclusion, and breast cancer cell growth. Combination treatment with iPRMT1 and inhibitors targeting SRSF1 phosphorylation exhibits an additive effect of suppressing breast cancer cell growth. In conclusion, our study dissects a mechanism underlying PRMT1-mediated RNA alternative splicing. Thus, PRMT1 has great potential as a therapeutic target in breast cancer treatment.

The inhibitory effect of Gremlin-2 on adipogenesis suppresses breast cancer cell growth and metastasis

BackgroundGremlin-1 (GREM1) and Gremlin-2 (GREM2) are bone morphogenetic protein antagonists that play important roles in organogenesis, tissue differentiation, and tissue homeostasis. Although GREM1 has been reported to be involved in promoting various cancers, little has been reported about effects of GREM2 on cancer. Recently, it has been reported that GREM2 can inhibit adipogenesis in adipose-derived stromal/stem cells. However, as an inhibitor of adipogenesis, the role of GREM2 in cancer progression is not well understood yet.MethodsPre-adipocyte 3T3-L1 cells overexpressing mock or Grem2 were established using a lentiviral transduction system and differentiated into adipocytes-mock and adipocytes-Grem2, respectively. To investigate the effect of adipocyte-Grem2 on breast cancer cells, we analyzed the proliferative and invasion abilities of spheroids using a 3D co-culture system of breast cancer cells and adipocytes or conditioned medium (CM) of adipocytes. An orthotopic breast cancer mouse model was used to examine the role of adipocytes-Grem2 in breast cancer progression.ResultsGrem2 overexpression suppressed adipogenesis of 3T3-L1 cells. Proliferative and invasion abilities of spheroids formed by co-culturing MTV/TM-011 breast cancer cells and adipocytes-Grem2 were significantly reduced compared to those of spheroids formed by co-culturing MTV/TM-011 cells and adipocytes-mock. Compared to adipocytes-mock, adipocytes-Grem2 showed decreased mRNA expression of several adipokines, notably IL-6. The concentration of IL-6 in the CM of these cells was also decreased. Proliferative and invasive abilities of breast cancer cells reduced by adipocytes-Grem2 were restored by IL-6 treatment. Expression levels of vimentin, slug, and twist1 in breast cancer cells were decreased by treatment with CM of adipocytes-Grem2 but increased by IL-6 treatment. In orthotopic breast cancer mouse model, mice injected with both MTV/TM-011 cells and adipocytes-Grem2 showed smaller primary tumors and lower lung metastasis than controls. However, IL-6 administration increased both the size of primary tumor and the number of metastatic lung lesions, which were reduced by adipocytes-Grem2.ConclusionsOur study suggests that GREM2 overexpression in adipocytes can inhibit adipogenesis, reduce the expression and secretion of several adipokines, including IL-6, and ultimately inhibit breast cancer progression.

Circ_0001982 aggravates breast cancer development through the circ_0001982-miR-144-3p-GSE1 axis.

This study was designed to explore the role of circ_0001982 in breast cancer (BC) development.Quantitative real-time polymerase chain reaction and western blot analysis assays were used to determine circ_0001982, miR-144-3p, and gse1 coiled-coil protein (GSE1) expression. Functional assays were performed to evaluate cell proliferation, apoptosis, migration, and invasion. The glycolysis was analyzed with commercial kits. Dual-luciferase reporter assay and RNA immunoprecipitation assays were conducted to analyze the relationships among circ_0001982, miR-144-3p, and GSE1. A murine xenograft model assay was performed to determine circ_0001982-induced effects on BC cell tumor properties in vivo.Circ_0001982 expression was upregulated, but miR-144-3p was reduced in BC tissues and cells in comparison with normal breast tissues and normal human mammary epithelial cells. Circ_0001982 knockdown or miR-144-3p overexpression inhibited BC cell proliferation, glycolysis, migration and invasion, and promoted apoptosis. Circ_0001982 sponged miR-144-3p and negatively regulated miR-144-3p expression in BC cells. In addition, GSE1 was identified as a target mRNA of miR-144-3p. Ectopic GSE1 expression relieved circ_0001982 depletion-induced effects on BC cell tumor properties. Furthermore, circ_0001982 absence suppressed BC cell tumor properties in vivo.Circ_0001982 contributed to the BC cell tumor properties by regulating the miR-144-3p-GSE1 axis.

PROS1, a clinical prognostic biomarker and tumor suppressor, is associated with immune cell infiltration in breast cancer: A bioinformatics analysis combined with experimental verification

BackgroundPROS1 is an encoding gene that can generate protein S. This protein is a glycoprotein found in plasma that conducts physiological functions with vitamin K. However, the impact of its expression remains absent in the progression and prognosis of breast cancer (BC). MethodsIn this study, we comprehensively explored the expression of PROS1 in BC and its relationship with BC patient survival, prognosis, and other clinicopathological features. We investigated how PROS1 influenced the malignant biological behavior of BC cells. A series of enrichment analyses were conducted, and the immune landscape was explored in BC affected by PROS1. We also determined correlations between PROS1 and common drug sensitivities used for BC treatments. ResultsPROS1 had low expression in BC, which tended to result in poor survival of BC patients. Overexpressed PROS1 inhibited the migration and invasion of BC cells as well as the epithelial–mesenchymal transition process by downregulating SNAIL. Functional enrichment analyses revealed that PROS1 was more active in extracellular matrix (ECM) organization and structural constituent, ECM-receptor interaction, and other pathways with its related genes. PROS1 was also found to affect immune activity, including various immune cells infiltrating BC. BC patients with high PROS1 expression tended to have lower IC50 values of three common medications and obtained better efficacy. ConclusionsPROS1 can become a promising prognostic factor and a possible therapeutic target in BC patients and suppress BC cell metastatic potential. In addition, PROS1 is a crucial factor in immune infiltration in BC.

THU557 Effects Of Two Experimental Monocarbonyl Analogs Of Curcumin (MACs) On Breast Cancer Growth, Migration, And Epithelial-To-Mesenchymal Transition (EMT)

Abstract Disclosure: R. Stojchevski: None. N. Hadzi-Petrushev: None. M. Mladenov: None. J. Bogdanov: None. S. Velichkovikj: None. L. Poretsky: None. D.B. Avtanski: None. Curcumin, a polyphenol found in turmeric (Curcuma longa), has been reported to have a range of potential therapeutic effects, including anti-inflammatory and antioxidant properties. However, curcumin’s poor bioavailability has limited its use in medicine. Monocarbonyl analogs of curcumin (MACs) have been developed to overcome this challenge and have shown promise in various medical applications, including cancer. Our previous experiments in animals showed that these two analogs possess potent antioxidant properties. The aim of this study was to investigate the in vitro effects of two experimental MACs (C66 (C22H16F6O) and B2BrBC (C20H16Br2O)) on breast cancer cell growth and epithelial-to-mesenchymal transition (EMT). Both C66 and B2BrBC significantly suppressed MCF-7 and BT-474 viability shown by MTT assay. These two analogs also suppressed breast cancer cell migration, demonstrated by scratch migration wound-healing assay using MCF-7 and MDA-MB-231 cells. Further, using qRT-PCR, we investigated the effects of C66 and B2BrBC on the expression of various epithelial (E-cadherin, cytokeratin-18) and mesenchymal (snail, slug, fibronectin, and vimentin) genes in MCF-7 cells subjected to EMT induction (a media supplement containing Wnt-5a, TGFβ1, anti-E-cadherin, anti-sFRP1, and anti-Dkk-1 antibodies). Since the EMT-induction media significantly downregulated the epithelial markers’ and upregulated the mesenchymal markers’ mRNA expression, these effects were significantly abolished when C66 or B2BrBC were introduced. Taken together, these data demonstrate that C66 and B2BrBC are potent agents for suppressing breast cancer cell growth and EMT in vitro. Further investigation is needed to determine the potential clinical use of these compounds in breast cancer treatment. Presentation: Thursday, June 15, 2023

Histone methyltransferase inhibitor UNC0642 promotes breast cancer cell death by upregulating TXNIP-dependent oxidative stress

Breast cancer (BC) is one of the most frequent type of cancer in women worldwide. Current therapeutic strategies for BC are not always effective. In this study, we investigated the anticancer activity of an epigenetic compound UNC0642 and its mechanism of action in suppressing BC cell growth and survival. UNC0642 was developed as a selective inhibitor of G9a that is responsible for histone H3K9 methylation. After screening different BC cell lines, we found UNC0642 had the lowest IC-50 against MDA-MB-231 cells, a triple-negative BC cell line. To identify additional UNC0642 targets, we performed RNA-seq analyses in BC cells following UNC0642 treatment. UNC0642 significantly upregulated mRNA expression of thioredoxin-interacting protein (TXNIP), which was also validated by western blotting. We further showed that TXNIP upregulation was associated with dose-dependent elevation of reactive oxygen species, concurrent with loss of mitochondrial membrane potential and activation of caspase-3-dependent apoptosis. Finally, we demonstrated that UNC0642 treatment induced BC cell apoptosis in vitro and suppression of tumor growth in xenograft mouse models that was coupled with TXNIP activation. Taken together, our results show that UNC0642 exerts its antitumor function via upregulating TXNIP expression and oxidative stress to impair mitochondrial function and induce caspase-dependent cell death. This observation could inform future breast cancer therapies by targeting TXNIP-dependent ROS signaling.

ZNF500 abolishes breast cancer proliferation and sensitizes chemotherapy by stabilizing P53 via competing with MDM2.

Zinc finger protein 500 (ZNF500) has an unknown expression pattern and biological function in human tissues. Our study revealed that the ZNF500 mRNA and protein levels were higher in breast cancer tissues than those in their normal counterparts. However, ZNF500 expression was negatively correlated with advanced TNM stage (p = 0.018), positive lymph node metastasis (p = 0.014), and a poor prognosis (p < 0.001). ZNF500 overexpression abolished in vivo and in vitro breast cancer cell proliferation by activating the p53-p21-E2F4 signaling axis and directly interacting with p53 via its C2H2 domain. This may prevent ubiquitination of p53 in a manner that is competitive to MDM2, thus stabilizing p53. When ZNF500-∆C2H2 was overexpressed, the suppressed proliferation of breast cancer cells was neutralized in vitro and in vivo. In human breast cancer tissues, ZNF500 expression was positively correlated with p53 (p = 0.022) and E2F4 (p = 0.004) expression. ZNF500 expression was significantly lower in patients with Miller/Payne Grade 1-2 than in those with Miller/Payne Grade 3-5 (p = 0.012). ZNF500 suppresses breast cancer cell proliferation and sensitizes cells to chemotherapy.

LINC-PINT suppresses breast cancer cell proliferation and migration via MEIS2/PPP3CC/NF-κB pathway by sponging miR-576-5p

BackgroundBreast cancer (BCa) is the most frequent malignant tumor in women. Long non-coding RNAs (lncRNAs) have been acknowledged to exert critical regulating functions in various cancers. Long intergenic non-protein coding RNA, p53 induced transcript (LINC-PINT) has been reported to be a chemosensitizer and a tumor suppressor in BCa. However, its downstream molecular mechanism contributing to its tumor-suppressing role remains to be explored in BCa. MethodsLINC-PINT expression in BCa tissues and cells was measured using quantitative real-time polymerase chain reaction (RT-qPCR). The proliferation of transfected BCa cells was examined by counting kit-8 (CCK-8) and EdU assay. The migrating ability of indicate BCa cells was assessed by wound healing assays. Bioinformatics analysis and mechanism experiments such as RNA immunoprecipitation (RIP), RNA pull down assay, and luciferase reporter assay, were applied to demonstrate the downstream targets of LINC-PINT. ResultsLINC-PINT was downregulated in BCa tissues and cell lines. Overexpression of LINC-PINT suppressed BCa cell proliferation and migration. LINC-PINT could interact with miR-576-5p to upregulate Meis homeobox 2 (MEIS2) that positively regulated protein phosphatase 3 catalytic subunit gamma (PPP3CC) by inactivating the nuclear factor-κB (NF-κB) pathway. ConclusionsThese findings elucidated the anti-tumor role of LINC-PINT in BCa via the miR-576-5p/MEIS2/PPP3CC/NF-κB axis, which suggested that LINC-PINT might serve as a potential therapeutic target for BCa.

FOXO1-regulated lncRNA CYP1B1-AS1 suppresses breast cancer cell proliferation by inhibiting neddylation.

Overactivated neddylation is considered to be a common event in cancer. Long non-coding RNAs (lncRNAs) can regulate cancer development by mediating post-translational modifications. However, the role of lncRNA in neddylation modification remains unclear. LncRNA cytochrome P450 family 1 subfamily B member 1 antisense RNA 1 (CYP1B1-AS1) expression in breast cancer tissues was evaluated by RT-PCR and TCGA BRCA data. Gain and loss of function experiments were performed to explore the role of CYP1B1-AS1 in breast cancer cell proliferation and apoptosis in vitro and in vivo. Luciferase assay, CHIP-qPCR assay, transcriptome sequencing, RNA-pulldown assay, mass spectrometry, RIP-PCR and Western blot were used to investigate the regulatory factors of CYP1B1-AS1 expression and the molecular mechanism of CYP1B1-AS1 involved in neddylation modification. We found that CYP1B1-AS1 was down-regulated in breast cancer tissues and correlated with prognosis. In vivo and in vitro functional experiments confirmed that CYP1B1-AS1 inhibited cell proliferation and induced apoptosis. Mechanistically, CYP1B1-AS1 was regulated by the transcription factor, forkhead box O1 (FOXO1), and could be upregulated by inhibiting the PI3K/FOXO1 pathway. Moreover, CYP1B1-AS1 bound directly to NEDD8 activating enzyme E1 subunit 1 (NAE1) to regulate protein neddylation. This study reports for the first time that CYP1B1-AS1 inhibits protein neddylation to affect breast cancer cell proliferation, which provides a new strategy for the treatment of breast cancer by lncRNA targeting neddylation modification.

Chemotherapy-induced exosomal circBACH1 promotes breast cancer resistance and stemness via miR-217/G3BP2 signaling pathway

BackgroundChemoresistance involves metastasis and aggressiveness of breast cancer (BC). Chemotherapy-elicited exosomes have been reported to be associated with drug resistance and pro-metastatic capacity of BC cells. Non-coding RNAs (ncRNAs) are enriched in exosomes, which participated in generation, progression, and resistance of BC. However, the mechanism underlying the chemoresistance and metastasis in BC cells mediated by the BC-derived exosomal ncRNAs remained to be elucidated.MethodsThe effects of PTX-induced exosomal circBACH1 on BC cell function were assessed using RNA Binding Protein Immunoprecipitation (RIP), dual luciferase reporter gene, tube formation, CCK-8, and Western Blot assays. The circBACH1 and miR-217 expression levels were detected using quantitative real-time PCR (RT-qPCR) and Immunohistochemistry (IHC) assays in BC tissues and precancerous tissues of BC patients.ResultsCircBACH1 expression was increased in paclitaxel-treated BC-derived exosomes (PTX-EXO) and BC tissue. PTX-EXO was shown to promote PTX-resistance and angiogenesis through upregulation circBACH1. Downregulation of circBACH1 improved PTX-sensitiveness by suppressing the cell viability, stemness, migration, and angiogenesis of BC cells. Moreover, we found that miR-217 interacted with circBACH1 and targeted GTPase-activating SH3 domain-binding protein 2 (G3BP2) in BC cells. CircBACH1 combined miR-217 cotransfection suppressed the expression of G3BP2 proteins compared with circBACH1 treatment in MCF-7 cells. In addition, downregulation of G3BP2 suppressed BC cell migration.ConclusionsThese results demonstrated that PTX-induced exosomal circBACH1 promoted stemness and migration of BC cells by sponging miR-217 to upregulate the expression of G3BP2, which provided a new therapeutic target for PTX-resistance and progression of BC via circBACH1/miR-217/G3BP2 axis.