Suppresses Breast Cancer Growth Research Articles

Glycyrrhetinic acid suppresses breast cancer metastasis by inhibiting M2-like macrophage polarization via activating JNK1/2 signaling

BackgroundBreast cancer metastasis is leading cause of cancer death among women worldwide. Tumor-associated macrophages (TAMs) have been considered as potential targets for treating breast cancer metastasis because they promote tumor growth and development. Glycyrrhetinic acid (GA) is one of the most important phytochemicals of licorice which has shown promising anti-cancer efficacies in pre-clinical trials. However, the regulatory effect of GA on the polarization of TAMs remains elusive. PurposeTo investigate the role of GA in regulating the polarization of M2 macrophages and inhibiting breast cancer metastasis, and to further explore its underlying mechanisms of action. Study DesignIL-4 / IL-13-treated RAW 264.7 and THP-1 cells were used as the M2-polarized macrophages in vitro. A 4T1 mouse breast cancer model and the tail vein breast cancer metastasis model were applied to study the effect of GA on breast cancer growth and metastasis in vivo. ResultsIn vitro studies showed that GA significantly inhibited IL-4 / IL 13-induced M2-like polarization in RAW 264.7 and THP-1 macrophages without affecting M1-like polarization. GA strongly decreased the expression of M2 macrophage markers CD206 and Arg-1, and reduced the levels of the pro-angiogenic molecules VEGF, MMP9, MMP2 and IL-10 in M2 macrophages. GA also increased the phosphorylation of JNK1/2 in M2 macrophages. Moreover, GA significantly suppressed M2 macrophage-induced cell proliferation and migration in 4T1 cancer cells and HUVECs. Interestingly, the inhibitory effects of GA on M2 macrophages were abolished by a JNK inhibitor. Animal studies showed that GA significantly suppressed tumor growth, angiogenesis, and lung metastasis in BALB/c mice bearing breast tumor. In tumor tissues, GA reduced the number of M2 macrophages but elevated the proportion of M1 macrophages, accompanied by activation of JNK signaling. Similar results were found in the tail vein breast cancer metastasis model. ConclusionThis study demonstrated for the first time that GA could effectively suppress breast cancer growth and metastasis by inhibiting macrophage M2 polarization via activating JNK1/2 signaling. These findings indicate that GA could be served as the lead compound for the future development of anti-breast cancer drug.

Coiled-coil domain containing 3 suppresses breast cancer growth by protecting p53 from proteasome-mediated degradation.

Coiled-coil domain containing 3 (CCDC3) was previously shown to regulate liver lipid metabolism as a secretory protein. Here, we report an unexpected intracellular role of CCDC3 as a tumor suppressor in breast cancer (BrC). Bioinformatics datasets analysis showed that CCDC3 is under-expressed in BrCs, while its higher levels are correlated with higher overall survival and lower relapse of cancer patients, and CCDC3 is positively correlated with p53 and its target genes. Ectopic CCDC3 markedly suppressed proliferation, colony formation, and xenograft tumor growth by augmenting p53 activity in BrC cells. Depletion of endogenous CCDC3 by CRISPR-Cas9 increased proliferation and drug resistance of BrC cells by alleviating 5-Fluorouracil (5-FU)-induced p53 level and activity. Mechanistically, CCDC3 bound to the C-termini of p53 and MDM2, consequently stabilizing p53 in the nucleus and impairing MDM2 recruitment of p53 to the 26S proteosome without inhibiting p53 ubiquitination. p53 induced CCDC3 expression by binding to its promoter in BrC cells. Our results unveil a unique mechanism underlying CCDC3 activation of p53 in a positive feedback fashion to suppress BrC growth.

Hsa_circ_0002082 up-regulates Centromere Protein F via abolishing miR-508-3p to promote breast cancer progression.

Circular RNAs (circRNAs) dysregulation has been revealed to function in the pathological processes of cancers. Herein, the role and mechanisms of hsa_circ_0002082 in breast cancer (BC) progression were elucidated. In vivo and in vitro functional experiments were conducted, and the interaction between miR-508-3p and hsa_circ_0002082 or Centromere Protein F (CENPF) was elucidated. Hsa_circ_0002082 expression was higher in BC tissues and cell lines. Functionally, knockdown of hsa_circ_0002082 induced apoptosis and suppressed proliferation and metastasis in BC cells in vitro. Mechanistically, hsa_circ_0002082 targeted miR-508-3p, which was confirmed to be decreased in BC. MiR-508-3p overexpression suppressed BC cell malignant phenotypes, moreover, inhibition of miR-508-3p attenuated the anticancer action of hsa_circ_0002082 silencing on BC cells. Besides that, miR-508-3p targeted CENPF, CENPF was highly expressed in BC, CENPF up-regulation reversed the suppressive impacts of miR-508-3p on BC cell growth and metastasis. Besides, hsa_circ_0002082 silencing impeded BC growth in nude mice. Knockdown of hsa_circ_0002082 suppresses breast cancer growth and metastasis by miR-508-3p/CENPF axis, suggesting that hsa_circ_0002082 may be a promising target for breast cancer treatment.

Valproic acid regulates MIEF1 through MST2-HIPPO to suppress breast cancer growth

AimsTo determine the effects of valproic acid (VPA) on anti-proliferative effects and mitochondrial function in breast cancer cells and the underlying mechanisms involved in the effects, with a focus on signal transduction. Main methodsThe inhibitory effect of valproic acid on breast cancer in vivo and in vitro was evaluated by cellular and animal experiments. Mitochondria-related proteins as well as hippo pathway were monitored by western blotting. The effects of VPA on mitochondrial membrane potential, reactive oxygen species, and apoptosis were confirmed by flow cytometry. In addition, the involvement of hippo pathway in the regulation of mitochondrial function by VPA was verified by XMU-MP-1 (MST2 inhibitor). Key findingsIn this study, we highlight that VPA significantly attenuates mitochondrial function, leading to inhibited cell proliferation and reduced colony formation in MCF-7 and MDA-MB-231 breast cancer cells. Mechanistically, VPA-induced suppression of mitochondrial aerobic respiration was mediated by decreased expression of mitochondrial elongation factor 1 through activation of the hippo pathway, resulting in impaired breast cancer growth. In summary, we uncover a novel mechanism of VPA in regulating mitochondrial aerobic respiration, which is essential for developing an effective approach in breast cancer therapy. SignificanceMitochondrial aerobic respiration and its products are the main sources of energy for tumors; therefore, studying the role of mitochondrial function in tumor cells is significant. VPA has been used as a therapeutic agent for cancer. However, the detail mechanism underlying the effects of VPA on mitochondrial function in breast cancer remains unclear.

LINC00536 knockdown inhibits breast cancer cells proliferation, invasion, and migration through regulation of the miR-4282/centromere protein F axis.

Breast cancer (BC) poses a huge threat to women's health. Growing evidence has shown lncRNAs play critical roles in BC progression. However, the effect of LINC00536 in BC remains unknown. LINC00536, miR-4282, and centromere protein F (CENPF) expressions in BC cells were determined using qPCR assay. Colony formation assay was employed to evaluate the cell proliferation of BC cells. Besides, cell migration and invasion were evaluated using the transwell assay. FISH assay was employed to analyze LINC00536 and miR-4282 locations in BC cells. Additionally, dual luciferase reporter gene assay was performed to verify the binding relationships between LINC00536 and miR-4282, miR-4282 and CENPF. Here, our results displayed that LINC00536 and CENPF were overexpressed in BC cells, while miR-4282 was downregulated. LINC00536 could negatively regulate miR-4282 expression via directly binding to miR-4282. LINC00536 silence suppressed the proliferation, migration, and invasion of BC cells, which was abolished by miR-4282 inhibition. Additionally, miR-4282 could negatively regulate CENPF expression via directly binding to CENPF. MiR-4282 overexpression suppressed BC development, which was abolished by CENPF overexpression. Finally, we proved that LINC00536 silencing suppressed BC growth via regulating the miR-4282/CENPF axis in vivo. Our research displayed that LINC00536 acted as an oncogene in BC. LINC00536-enhanced BC cell proliferation, migration, and invasion. Moreover, LINC00536 functioned as a ceRNA to exert malignant characteristics in BC via the miR-4282-CENPF axis. Collectively, our results demonstrated that the LINC00536-miR-4282-CENPF axis was a critical player in BC development and was a promising target for BC therapy.

Circular RNA KIF4A Promotes Liver Metastasis of Breast Cancer by Reprogramming Glucose Metabolism.

Background Circular RNAs (circRNAs) regulate complex functional processes and play crucial roles in cancer development and progression. It was reported that circKIF4 regulates the progression of triple-negative breast cancer (TNBC). This study evaluates the role of circKIF4 in breast cancer distant metastasis and metabolic reprogramming. Methods RT-qPCR was performed to verify the expression of circKIF4A in breast cancer, liver metastatic tissues, and cell lines. The function of circKIF4A in metastasis was evaluated both in vitro and in vivo through a series of experiments, including cell migration and glucose intake experiments. Additionally, we conducted molecular experiments to clarify the regulatory role of circKIF4A. We then conducted a Luciferase reporter assay and an RNA immunoprecipitation assay to identify the molecular interactions between circKIF4A and miRNA. Results circKIF4A was overexpressed in breast cancer cell lines and tissues, inhibiting its expression and suppressing breast cancer growth and metastasis. Interestingly, we observed that circKIF4A reprogrammed the glucose metabolism of breast cancer, and silencing circKIF4A greatly affected glucose uptake and lactate production in breast cancer cells. miR-335 can be sponged by circKIF4A, which affected the expression of ALDOA/OCT4 protein and regulated HK2/PKM2 expression. Conclusions This study demonstrated that the circKIF4A-miR-335-OCT4/ALDOA-HK2/PKM2 axis is critical to breast cancer metabolic reprogramming, indicating that this axis could be a novel therapeutic target for the treatment of liver metastasis of breast cancer.

LINC00092 Modulates Oxidative Stress and Glycolysis of Breast Cancer Cells via Pyruvate Carboxylase-Mediated AKT/mTOR Pathway.

Background The discovery of noncoding RNAs (ncRNAs) offers new options for cancer-targeted therapy. This study is aimed at exploring the regulatory function of LINC00092 on breast cancer (BC) oxidative stress and glycolysis, along with internal mechanism concerning pyruvate carboxylase (PC). Methods Bioinformatics analysis was used to explore LINC00092 (or friend leukemia virus integration 1 (FLI1)) expression on BC progression, as well as oxidative stress and glycolysis in BC. After LINC00092 overexpression or silence, BC cell viability, proliferation, migration, invasion, oxidative stress, glycolysis, and AKT/mTOR pathway were detected. Following 2-DG, SC79, or MK2206 treatment, effects of LINC00092 on BC cells were measured. Moreover, regulatory activity of LINC00092 in PC expression was analyzed. Whether PC participated in the modulation of LINC00092 on BC cell functions was explored. Results LINC00092 was lowly expressed in BC and negatively related to BC progression. FLI1 bound to LINC00092 promoter to positively modulate LINC00092. LINC00092 overexpression inhibited BC cell proliferation, migration, invasion, oxidative stress, glycolysis, and AKT/mTOR pathway and likewise suppressed BC growth in vivo. Silence of LINC00092 had opposite influences. 2-DG partially reversed the LINC00092 silence-resulted increase of BC cell proliferation. SC79 alleviated the function of LINC00092 overexpression on BC cell functions. MK2206 had the contrary influence of SC79. Besides, LINC00092 bound to PC to modulate ubiquitination degradation of PC protein. PC took part in the influences of LINC00092 on BC cell functions. Conclusions LINC0092 modulates oxidative stress and glycolysis of BC cells via the PC-mediated AKT/mTOR pathway, which is possibly a target for BC diagnosis and therapy.

Abstract 856: Coiled-coil domain containing 3 suppresses breast cancer growth by protecting p53 from proteasome-mediated degradation

Abstract Coiled-coil domain containing 3 (CCDC3) was previously shown to regulate liver lipid metabolism as a secretory protein. Our recent studies revealed an intracellular role of CCDC3 as a tumor suppressor in breast cancer (BrC). Bioinformatics datasets analysis showed that CCDC3 is under-expressed in BrCs, while its higher levels are correlated with higher overall survival and lower relapse of cancer patients. CCDC3 is positively correlated with p53 and its target genes. Ectopic CCDC3 markedly suppressed proliferation, colony formation, and xenograft tumor growth by augmenting p53 activity in BrC cells. In contrast, knockdown of endogenous CCDC3 using CRISPR led to reduction of p53 level and activity, consequently promoting the proliferation of BrC cells. Mechanistically, CCDC3 bound to the C-termini of p53 and MDM2, consequently stabilizing p53 in the nucleus and impairing MDM2 recruitment of p53 to the 26S proteosome without inhibiting p53 ubiquitination. Also, knockdown of CCDC3 caused the resistance of BrC cells to 5-FU to some degrees by alleviating p53 response to this drug. p53 induced CCDC3 expression by binding to its promoter specifically in BrC cells. Our results unveil a unique mechanism underlying CCDC3 activation of p53 in a positive feedback fashion to suppress BrC growth and suggest that CCDC3 deficiency could be a factor for drug resistance of BrCs. Citation Format: Hyemin Lee, Caiyue Li, Ji Hoon Jung, Yiwei Zhang, Jieqiong Wang, Chang Liu, Allyson M. Segall, Roger L. Sheffmaker, Shelya X. Zeng, Hua Lu. Coiled-coil domain containing 3 suppresses breast cancer growth by protecting p53 from proteasome-mediated degradation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 856.

"Derived Multiple Allogeneic Protein Paracrine Signaling (d-MAPPS)" Enhances T Cell-Driven Immune Response to Murine Mammary Carcinoma.

Breast cancer is considered refractory to immunotherapy. Accordingly, there is an urgent need for the therapeutic use of new immunostimulatory agents which would enhance antitumor immune response against breast cancer cells. “Derived Multiple Allogeneic Protein Paracrine Signaling (d-MAPPS)” is a biological product whose activity is based on chemokines and cytokines that modulate homing and phenotype of immune cells. d-MAPPS contains high concentration of dendritic cell (DC) and T cell-attracting chemokine CXCL16 and potent T cell-activating cytokine IL-27 which enhance DC:T cell cross-talk in inflamed tissues. Herewith, we used 4T1 murine model of breast cancer to analyze d-MAPPS-dependent enhancement of T cell-driven antitumor immunity. 4T1+d-MAPPS-treated mice showed delayed mammary tumor appearance compared to 4T1+saline-treated animals. d-MAPPS significantly reduced tumor weight and volume and improved survival of 4T1-treated mice. Significantly increased concentration of CXCL16, IL-27, IFN-γ, and IL-17 and decreased concentration of immunosuppressive TGF-β and IL-10 were measured in serum samples and tumor tissues of 4T1+d-MAPPS-treated mice. d-MAPPS enhanced production of IL-12 and increased expression of MHC class II and costimulatory molecules on tumor-infiltrated DC, significantly improving their antigen-presenting properties. d-MAPPS in CXCL16-dependent manner promoted recruitment of antitumorigenic IFN-γ/IL-17-producing CD4+Th1/Th17 cells and in IL-27-dependent manner induced expansion of tumoricidal CD178+granzyme B-expressing CD8+CTLs and inhibited generation of tolerogenic DC, IL-10, and TGF-β-producing FoxP3-expressing T regulatory cells. In summing up, d-MAPPS, in CXL16- and IL-27-dependent manner, enhanced T cell-driven antitumor immune response and suppressed breast cancer growth in experimental mice.

Abstract 2301: Targeting the MUVB complex or downstream G2/M proteins potentiates CDK4/6 inhibitor efficacy in breast cancer

Abstract Uncontrolled progression through the cell cycle sustains the growth and progression of cancer. The cell cycle is comprised of 4 phases that are tightly regulated by two key transcriptional modulators, RB-E2F and MUVB complexes that regulate gene expression during the G1/S and G2/M cell cycle transitions, respectively. Target transcriptomes of both complexes overlap, suggesting that maximal inhibition of cell cycle progression, requires targeting both. Inhibitors that regulate the RB-E2F signaling axis have been FDA approved for treatment of a subset of breast cancers. These drugs specifically inhibit two kinases involved in the cell cycle known as CDK4 and CDK6. Palbociclib and abemaciclib, CDK4/CDK6 inhibitors (CDK4/6i), decrease cell proliferation by inducing a G1 cell cycle arrest. In contrast to CDK4/6, we previously reported that the activity of MUVB complex can be repressed using inhibitors of BET proteins, including the tool compound, JQ1. We hypothesized that dual targeting of MUVB and CDK4/CDK6 will synergize in breast cancer models to further decrease growth. To test this hypothesis, we assessed the impact of growth by adding JQ-1 to CDK4/6i in multiple intrinsically resistant cell lines. We found that addition of JQ-1 reduced IC50 of CDK4/6i by 60-75% and that the combination displayed synergistic growth suppression. Mechanistically, analysis of mRNA and protein expression revealed that the combination had greater ability to suppress expression of proteins that are MUVB target genes, G2/M, compared to single agents. We found through genetic and pharmacological approaches that inhibition of G2/M proteins Aurora Kinase A and NEK2 mediated CDK4/6i inhibitor response. Preclinical xenograft models confirmed that combined inhibition of CDK4/6 and MUVB, NEK2, or Aurora Kinase A can synergistically suppress tumor growth. Together, these results indicate that dual targeting of distinct phases of the cell cycle should be a more efficacious approach for suppressing breast cancer growth and provide a potential approach for blocking the acquisition of resistance to CDK4/6 inhibitors, a major clinical challenge for the treatment of luminal breast cancer. Citation Format: Leslie Cuellar-Vite, Kristen Weber-Bonk, Ruth A. Keri. Targeting the MUVB complex or downstream G2/M proteins potentiates CDK4/6 inhibitor efficacy in breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2301.

F-box protein FBXO41 suppresses breast cancer growth by inducing autophagic cell death through facilitating proteasomal degradation of oncogene SKP2.

F-box proteins form SCF (Cullin1, SKP1 and F-box-protein) ubiquitin ligase complexes to ubiquitinate cellular proteins. They play key role in several biological processes, including cell cycle progression, cellular signaling, stress response and cell death pathways. Therefore, deregulation of F-box proteins is closely associated with cancer progression. However, the role of most of the F-box proteins, including FBXO41, in cancer progression remains elusive. Here, we unravel the role of FBXO41 in cancer progression. We show that FBXO41 suppresses cancer cell proliferation and tumor growth by inducing autophagic cell death through an alternative pathway. Results revealed that FBXO41-mediated autophagic cell death induction is dependent on accumulation of cell cycle checkpoint protein p21. We found that FBXO41 increases the expression levels of p21 at the post-translational level by promoting the proteasomal degradation of SKP2, an oncogenic F-box protein. Mechanistically, FBXO41 along with p21 disrupts the inhibitory BCL2 (anti-apoptotic protein)-Beclin1 (autophagy initiating factor) complex of autophagy induction to release Beclin1, thereby inducing autophagy. Overall, the present study establishes a new FBXO41-SKP2-p21 axis for induction of autophagic cell death to prevent cancer growth, which could be explored to develop promising cancer therapeutics.

Targeting aberrant replication and DNA repair events for treating breast cancers

The major limitations of DNA-targeting chemotherapy drugs include life-threatening toxicity, acquired resistance and occurrence of secondary cancers. Here, we report a small molecule, Carbazole Blue (CB), that binds to DNA and inhibits cancer growth and metastasis by targeting DNA-related processes that tumor cells use but not the normal cells. We show that CB inhibits the expression of pro-tumorigenic genes that promote unchecked replication and aberrant DNA repair that cancer cells get addicted to survive. In contrast to chemotherapy drugs, systemic delivery of CB suppressed breast cancer growth and metastasis with no toxicity in pre-clinical mouse models. Using PDX and ex vivo explants from estrogen receptor (ER) positive, ER mutant and TNBC patients, we further demonstrated that CB effectively blocks therapy-sensitive and therapy-resistant breast cancer growth without affecting normal breast tissue. Our data provide a strong rationale to develop CB as a viable therapeutic for treating breast cancers.

Glipizide Combined with ANP Suppresses Breast Cancer Growth and Metastasis by Inhibiting Angiogenesis through VEGF/VEGFR2 Signaling.

Breast cancer is one of the most common cancers worldwide among women, and angiogenesis has an important effect on its growth and metastasis. Glipizide, which is a widely used drug for type 2 diabetes mellitus, has been reported to inhibit tumor growth and metastasis by upregulating the expression of natriuretic peptide receptor A (NPRA). Atrial natriuretic peptide (ANP), the receptor of NPRA, plays an important role in angiogenesis. The purpose of this study was to explore the effect of glipizide combined with ANP on breast cancer growth and metastasis. This study aimed at investigating the effect of glipizide combined with ANP on breast cancer. Glipizide, ANP, or glipizide combined with ANP was intraperitoneally injected into MMTV-PyMT mice. To explore whether the anticancer efficacy of glipizide combined with ANP was correlated with angiogenesis, a tube formation assay was performed. Glipizide combined with ANP was found to inhibit breast cancer growth and metastasis in MMTV-PyMT mice, which spontaneously develop breast cancer. Furthermore, the inhibitory effect of ANP combined with glipizide was better than that of glipizide alone. ANP combined with glipizide significantly inhibited tube formation of human umbilical vein endothelial cells (HUVECs) by suppressing vascular endothelial growth factor (VEGF)/VEGFR2 (vascular endothelial growth factor receptor 2) signaling. These results demonstrate that glipizide combined with ANP has a greater potential than glipizide alone to be repurposed as an effective agent for the treatment of breast cancer by targeting tumor-induced angiogenesis.

DNA methyltransferase 1 inhibits microRNA-497 and elevates GPRC5A expression to promote chemotherapy resistance and metastasis in breast cancer

BackgroundAbnormal DNA methylation of tumor suppressor gene promoter has been found in breast cancer. Therefore, the current study set out to explore how DNA methyltransferase 1 (DNMT1) affects breast cancer through mediating miR-497/GPRC5A axis.MethodsAfter loss and gain-of-function approaches were conducted in MCF-7/ADR and MCF-7 cells, cell viability, IC50 value, invasion, migration and apoptosis were measured, respectively. In addition, drug resistance, metastasis and apoptosis-related protein expression were examined using immunoblotting. ChIP and dual-luciferase reporter gene assays were carried out to validate relationship among DNMT1, miR-497, and GPRC5RA. Subcutaneous xenograft tumor model in nude mice was established to detect effects of DNMT1 on growth and metastasis of breast cancer in vivo.ResultsIt was found that DNMT1 was notably increased, while miR-497 was poorly-expressed in breast cancer. Highly-expressed DNMT1 could promote chemotherapy resistance and metastasis of breast cancer. Meanwhile, DNMT1 modified methylation of CpG island in miR-497 promoter region, thereby repressing miR-497 level. In addition, miR-497 targeted GPRC5A expression to curb chemotherapy resistance and metastasis of breast cancer cells. Lastly, in vivo experiments showed that knockdown of DNMT1 could suppress breast cancer growth and metastasis.ConclusionsCollectively, our findings indicated that DNMT1 may inhibit miR-497 and boost the expression of GPRC5A through methylation, thus augmenting breast cancer chemotherapy resistance and metastasis, which provides novel mechanistic insight into the unrecognized roles of DNMT1 in breast cancer.

Interaction between BEND5 and RBPJ suppresses breast cancer growth and metastasis via inhibiting Notch signaling.

High frequent metastasis is the major cause of breast cancer (BC) mortality among women. However, the molecular mechanisms underlying BC metastasis remain largely unknown. Here, we identified six hub BC metastasis driver genes (BEND5, HSD11B1, NEDD9, SAA2, SH2D2A and TNFSF4) through bioinformatics analysis, among which BEND5 is the most significant gene. Low BEND5 expression predicted advanced stage and shorter overall survival in BC patients. Functional experiments showed that BEND5 could suppress BC growth and metastasis in vitro and in vivo. Mechanistically, BEND5 inhibits Notch signaling via directly interacting with transcription factor RBPJ/CSL. BEN domain of BEND5 interacts with the N-terminal domain (NTD) domain of RBPJ, thus preventing mastermind like transcriptional coactivator (MAML) from forming a transcription activation complex with RBPJ. Our study provides a novel insight into regulatory mechanisms underlying Notch signaling and suggests that BEND5 may become a promising target for BC therapy.

Glipizide Combined with ANP Suppresses Breast Cancer Growth and Metastasis by Inhibiting Angiogenesis through VEGF/VEGFR2 Signaling

Glipizide Combined with ANP Suppresses Breast Cancer Growth and Metastasis by Inhibiting Angiogenesis through VEGF/VEGFR2 Signaling

Abstract P139: An estrogen receptor beta agonist liquiritigenin potentiates inhibition of hormone-dependent breast-cancer growth by cholesterol biosynthesis inhibitor RO 48-8071

Abstract Hormone-dependent breast cancer represents approximately 70% of all diagnosed breast cancers. Estrogens and progestins stimulate breast cancer cell proliferation, angiogenesis and metastasis. Estrogen receptor (ER)-alpha positive breast cancers are treated with anti-estrogens and aromatase inhibitors, but resistance to these agents invariably develops during the course of therapy. Our goal was to identify novel treatment strategies to suppress breast cancer growth and avoid drug resistance. Cholesterol biosynthesis plays a vital role in tumor cell growth. Cholesterol is an integral part of membrane structure and is also a precursor of steroid hormones that are synthesized by tumor cells and cause cellular proliferation by interacting with specific receptors. Cancer cells have elevated levels of cholesterol, which could be responsible for anti-hormone resistance. During studies to determine the effects of the cholesterol biosynthesis inhibitor RO 48-8071 ([4’-[6-(Allylmethylamino)hexyloxy]-4-bromo-2’-fluorobenzophenone fumarate] (RO), which inhibits oxidosqualene cyclase (OSC), an enzyme that acts downstream of HMG-CoA reductase to convert 2, 3-monoepoxysqualene to lanosterol (a key step in the biosynthesis of cholesterol), it was serendipitously discovered that RO degraded ER-alpha (ERa), and elevated levels of ER-beta (ERb), a known tumor suppressor. We tested RO alone and in combination with liquiritigenin (LQ), a selective agonist for ERb, to ascertain their inhibitory effects against tumor cell progression. RO or LQ alone reduced significantly the in vitro viability of MCF-7 and BT-474 breast-cancer cells. BT-474 cells were more sensitive than MCF-7 cells to LQ (IC50 0.15 uM vs 0.25 mM, respectively). RO (5-10 uM) + LQ (0.1-0.3 mM) treatment reduced cell viability in an additive manner in MCF-7 cells and in a synergistic manner in BT-474 cells. Combination treatment was significantly more effective than treatment with a single agent. Administration of RO (10 mg/kg/iv) or LQ (20 mg/kg/ip) significantly inhibited growth of tamoxifen-resistant BT-474 tumor xenografts in vivo; combination treatment was even more effective. Both agents appeared to be non-toxic in vivo. Mechanistically, RO, LQ, or RO + LQ reduced ERa but induced ERb expression in tumor xenografts. Both compounds significantly reduced expression of markers of angiogenesis and increased apoptosis in tumor xenografts; use of RO + LQ significantly enhanced the effects observed with a single agent. The anti-tumor properties of RO may in part be due to an off-target effect that reduces ERa and increases ERb, the latter then interacting with LQ to more effectively promote its anti-proliferative effects. The potent anti-tumor properties of RO and LQ, particularly when used together, suggest that this combination has substantial potential as a means by which to clinically manage breast-cancer growth, including in disease types that are tamoxifen resistant. Citation Format: Yayun Liang, Salman Hyder. An estrogen receptor beta agonist liquiritigenin potentiates inhibition of hormone-dependent breast-cancer growth by cholesterol biosynthesis inhibitor RO 48-8071 [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr P139.

Physciosporin suppresses mitochondrial respiration, aerobic glycolysis, and tumorigenesis in breast cancer

BackgroundPhysciosporin (PHY) is one of the potent anticancer lichen compound. Recently, PHY was shown to suppress colorectal cancer cell proliferation, motility, and tumorigenesis through novel mechanisms of action. PurposeWe investigated the effects of PHY on energy metabolism and tumorigenicity of the human breast cancer (BC) cells MCF-7 (estrogen and progesterone positive BC) and MDA-MB-231 (triple negative BC). MethodsThe anticancer effect of PHY on cell viability, motility, cancer metabolism and tumorigenicity was evaluated by MTT assay, migration assay, clonogenic assay, anchorage-independent colony formation assay, glycolytic and mitochondrial metabolism analysis, qRT-PCR, flow cytometric analysis, Western blotting, immunohistochemistry in vitro; and by tumorigenicity study with orthotopic breast cancer xenograft model in vivo. ResultsPHY markedly inhibited BC cell viability. Cell-cycle profiling and Annexin V–FITC/PI double staining showed that a toxic dosage of PHY triggered apoptosis in BC cell lines by regulating the B-cell lymphoma-2 (Bcl-2) family proteins and the activity of caspase pathway. At non-toxic concentrations, PHY potently decreased migration, proliferation, and tumorigenesis of BC cells in vitro. Metabolic studies revealed that PHY treatment significantly reduced the bioenergetic profile by decreasing respiration, ATP production, and glycolysis capacity. In addition, PHY significantly altered the levels of mitochondrial (PGC-1α) and glycolysis (GLUT1, HK2 and PKM2) markers, and downregulated transcriptional regulators involved in cancer cell metabolism, including β-catenin, c-Myc, HIF-1α, and NF-κB. An orthotopic implantation mouse model of BC confirmed that PHY treatment suppressed BC growth in vivo and target genes were consistently suppressed in tumor specimens. ConclusionThe findings from our in vitro as well as in vivo studies exhibit that PHY suppresses energy metabolism as well as tumorigenesis in BC. Especially, PHY represents a promising therapeutic effect against hormone-insensitive BC (triple negative) by targeting energy metabolism.

Abstract 1238: Treating estrogen receptor (ER)-negative and triple-negative breast cancer by targeting STAT3 signaling with putative STAT3 inhibitors

Abstract Approximately 20% to a quarter of breast cancer cases are estrogen receptor (ER)-negative breast cancer (ENBC), including the most aggressive subtype, triple-negative breast cancer (TNBC), which spreads early and shows poor prognosis. ENBCs do not respond to selective ER modulators such as tamoxifen. Therefore, there is an urgent need for non-ER-based therapies for ENBC. Recently, STAT3 was found to play an important role in maintaining cancer stem cells in vitro and in mouse models of human cancers. In addition, during mammary carcinogenesis, STAT3 is highly activated in mammary epithelial cells involving in mammary epithelial cell transformation, tumor initiation, progression, and metastasis. STAT3 has been traditionally considered as non-targetable or undruggable, and there is currently a lack of FDA-approved STAT3 inhibitors for clinical use. We recently developed a putative STAT3 inhibitor, HJC0152, and a series of HJC0152-based analogues as orally bioavailable STAT3 inhibitors. These small molecules have been evaluated and a number of them showed low micro-molar potency in inhibiting the proliferation of a panel of breast cancer cell lines. Compound JMX0804 showed improved anti-proliferative effects against the highly aggressive TNBC cell line MDA-MB-231 and other ER+ and ER- breast cancer cell lines in comparison to HJC0152. JMX0804 inhibited STAT3 phosphorylation at the Tyr705 residue and induced apoptosis in MDA-MB-231 cells. In vivo, mice treated with JMX0804 at a 10 mg/kg dose via i.p. showed reduced growth of xenograft tumors arisen from MDA-MB-231 cells, with minimal impact on general health and body weight. Our current research supports the notion that JMX0804 suppresses breast cancer growth by inhibiting breast cancer cell proliferation and inducing apoptosis via mediating STAT3 signaling. JMX0804 is currently undergoing further characterization for breast cancer metastasis and mechanisms of action as well as optimization to improve drug properties including potency and safety profile. This work is supported by NIH/NCI grant R01 CA231150. Citation Format: Hyejin Kim, Doerte R. Fricke, Jimin Xu, Haiying Chen, Jia Zhou, Qiang Shen. Treating estrogen receptor (ER)-negative and triple-negative breast cancer by targeting STAT3 signaling with putative STAT3 inhibitors [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 1238.

Metformin suppresses breast cancer growth via inhibition of cyclooxygenase‑2

Pre-clinical and on-going trials have indicated the advantage of using metformin as an anticancer drug alone or in combination with other chemotherapeutics for the treatment of patients with breast cancer. However, the mechanisms by which metformin attenuates tumorigenesis remain to be further elucidated. The present study investigated the anticancer effects of metformin in breast cancer and identified potential molecular targets of metformin using western blotting and immunohistochemical analysis. Metformin significantly decreased tumor cell proliferation in vitro and suppressed tumor growth in vivo. Moreover, it induced the activation of AMP-induced protein kinase and suppression of phosphorylated-eukaryotic translation initiation factor 4E-binding protein 1 (p-4E-BP1), a downstream effector of the mTOR signaling pathway, and decreased cyclin D1 levels in in vitro and in vivo experimental models. Additionally, metformin inhibited cyclooxygenase (COX)-2 expression. Clinically, high expression levels of COX-2 and p-4E-BP1 in tissues of patients with breast cancer were significantly associated with enhanced lymphatic metastasis and distant metastasis. Thus, the current data suggested that metformin may have potential value as a synergistic therapy targeting both the COX-2 and mTOR signaling pathways.