Axis In Breast Cancer Research Articles

Inhibition of HDACs-EphA2 Signaling Axis with WW437 Demonstrates Promising Preclinical Antitumor Activity in Breast Cancer

Histone deacetylase inhibitors (HDACi) are small molecules targeting epigenetic enzymes approved for hematologic neoplasms, which have also demonstrated clinical activities in solid tumors. In our present study, we screened our internal compound library and discovered a novel HDACi, WW437, with potent anti-breast cancer ability in vitro and in vivo. WW437 significantly inhibited phosphorylated EphA2 and EphA2 expression. Further study demonstrated WW437 blocked HDACs-EphA2 signaling axis in breast cancer. In parallel, we found that EphA2 expression positively correlates with breast cancer progression; and combined use of WW437 and an EphA2 inhibitor (ALW-II-41-27) exerted more remarkable effect on breast cancer growth than either drug alone. Our findings suggested inhibition of HDACs-EphA2 signaling axis with WW437 alone or in combination with other agents may be a promising therapeutic strategy for advanced breast cancer.

BRD7 inhibits the Warburg effect and tumor progression through inactivation of HIF1\u03b1/LDHA axis in breast cancer

The bromodomain-containing protein 7 (BRD7) was first identified as a tumor suppressor in nasopharyngeal carcinoma and has critical roles in cancer development and progression. However, the regulatory roles and mechanisms of BRD7 in cancer metabolism are still unknown. In this study, we demonstrated that BRD7 was lowly expressed in breast cancer tissues and was identified as a poor prognostic factor in breast cancer. Meanwhile, BRD7 could suppress cell proliferation, initiate cell apoptosis and reduce aerobic glycolysis, suggesting that BRD7 plays a tumor suppressive roles in breast cancer. Mechanistically, BRD7 could negatively regulate a critical glycolytic enzyme LDHA through directly interaction with its upstream transcription factor, HIF1α, facilitating degradation of HIF1α mediated by ubiquitin–proteasome pathway. Moreover, restoring the expression of LDHA in breast cancer cells could reverse the effect of BRD7 on aerobic glycolysis, cell proliferation, and tumor formation, as well as the expression of cell cycle and apopotosis related molecules such as cyclin D1, CDK4, P21, and c-PARP both in vitro and in vivo. Taken together, these results indicate that BRD7 acts as a tumor suppressor in breast cancer and represses the glycolysis and tumor progression through inactivation of HIF1α/LDHA transcription axis.

TP53INP1 inhibits hypoxia-induced vasculogenic mimicry formation via the ROS/snail signalling axis in breast cancer.

Tumour protein p53‐inducible nuclear protein 1 (TP53INP1) is a tumour suppressor associated with malignant tumour metastasis. Vasculogenic mimicry (VM) is a new tumour vascular supply pattern that significantly influences tumour metastasis and contributes to a poor prognosis. However, the molecular mechanism of the relationship between TP53INP1 and breast cancer VM formation is unknown. Here, we explored the underlying mechanism by which TP53INP1 regulates VM formation in vitro and in vivo. High TP53INP1 expression was not only negatively correlated with a poor prognosis but also had a negative relationship with VE‐cadherin, HIF‐1α and Snail expression. TP53INP1 overexpression inhibited breast cancer invasion, migration, epithelial‐mesenchymal transition (EMT) and VM formation; conversely, TP53INP1 down‐regulation promoted these processes in vitro by functional experiments and Western blot analysis. We established a hypoxia model induced by CoCl2 and assessed the effects of TP53INP1 on hypoxia‐induced EMT and VM formation. In addition, we confirmed that a reactive oxygen species (ROS)‐mediated signalling pathway participated in TP53INP1‐mediated VM formation. Together, our results show that TP53INP1 inhibits hypoxia‐induced EMT and VM formation via the ROS/GSK‐3β/Snail pathway in breast cancer, which offers new insights into breast cancer clinical therapy.

MicroRNA-155 positively regulates glucose metabolism via PIK3R1-FOXO3a-cMYC axis in breast cancer

MicroRNA is an endogenous, small RNA controlling multiple target genes and playing roles in various biological processes including tumorigenesis. Here, we addressed the function of miR-155 using LC-MS/MS-based metabolic profiling of miR-155 deficient breast cancer cells. Our results revealed the loss of miR-155 hampers glucose uptake and glycolysis, via the down-regulation of glucose transporters and metabolic enzymes including HK2, PKM2, and LDHA. We showed this is due to the down-regulation of cMYC, controlled through phosphoinositide-3-kinase regulatory subunit alpha (PIK3R1)-PDK1/AKT-FOXO3a pathway. UTR analysis of the PIK3R1 and FOXO3a indicated miR-155 directly represses these genes. A stable expression of miR-155 in patient-derived cells (PDCs) showed activated glucose metabolism whereas a stable inhibition of miR-155 reduced in vivo tumor growth with retarded glucose metabolism. Furthermore, analysis of 50 triple-negative breast cancer (TNBC) specimens and specific uptake value (SUV) of PET images revealed a positive correlation between miR-155 level and glucose usage in human breast tumors via PIK3R1-PDK/AKT-FOXO3a-cMYC axis. Collectively, these data demonstrate the miR-155 is a key regulator of glucose metabolism in breast cancer.

LncRNA HOTAIR influences cell growth, migration, invasion, and apoptosis via the miR-20a-5p/HMGA2 axis in breast cancer.

To study the regulatory effect of lncRNA HOTAIR/miR‐20a‐5p/HMGA2 axis on breast cancer (BC) cell growth, cell mobility, invasiveness, and apoptosis. The microarray data of lncRNAs and mRNAs with differential expression in BC tissues were analyzed in the Cancer Genome Atlas (TCGA) database. LncRNA HOX transcript antisense RNA (lncRNA HOTAIR) expression in BC was assessed by qRT‐PCR. Cell viability was confirmed using MTT and colony formation assay. Cell apoptosis was analyzed by TdT‐mediated dUTP nick‐end labeling (TUNEL) assay. Cell mobility and invasiveness were testified by transwell assay. RNA pull‐down and dual luciferase assay were used for analysis of the correlation between lncRNA HOTAIR and miR‐20a‐5p, as well as relationship of miR‐20a‐5p with high mobility group AT‐hook 2 (HMGA2). Tumor xenograft study was applied to confirm the correlation of lncRNA HOTAIR/miR‐20a‐5p/HMGA2 axis on BC development in vivo. The expression levels of the lncRNA HOTAIR were upregulated in BC tissues and cells. Knockdown lncRNA HOTAIR inhibited cell propagation and metastasis and facilitated cell apoptosis. MiR‐20a‐5p was a target of lncRNA HOTAIR and had a negative correlation with lncRNA HOTAIR. MiR‐20a‐5p overexpression in BC suppressed cell growth, mobility, and invasiveness and facilitated apoptosis. HMGA2 was a target of miR‐20a‐5p, which significantly induced carcinogenesis of BC. BC cells progression was mediated by lncRNA HOTAIR via affecting miR‐20a‐5p/HMGA2 in vivo. LncRNA HOTAIR affected cell growth, metastasis, and apoptosis via the miR‐20a‐5p/HMGA2 axis in breast cancer.

Integrative analysis of CXCR4/CXCL12 axis gene expression alterations in breast cancer and its prognostic relevance

Cancer metastasis is the major delimiting factor in the failure of therapeutic strategies currently practised and epithelial-mesenchymal transition (EMT) has been observed to be one of the key regulators of metastasis as it confers the invasive phenotype. Chemokines have been shown to be directly involved in mediating the metastatic ability of cancer cells, particularly CXCR4 chemokine receptor. The purpose of the present study was to explore the expression levels of CXCR4/CXCL12 axis in different subtypes of breast cancer using dataset analysis. The mRNA expression levels and genomic alterations of CXCR4 and CXCL12 in different cancers were analyzed via the Oncomine and cBioPortal. In addition, co-expression analysis, mutations and clinical survival relevance has been analyzed in various datasets. Results of our analysis suggest a significant association of CXCR4/CXCL12 axis in breast cancer and as a potential prognostic biomarker.

Detecting the role of CCR7-CCL21/CCL19 axis in Breast Cancer Progression and lymph node Metastasis Incidence

Background: Metastasis is the main cause of death in breast cancer patients. Lymph node metastasis is associated with poor overall survival and is often associated with recurrences. The molecular mechanisms controlling tumor metastasis are complex and there is an emerging evidence supporting the direct involvement of the chemokines and their receptors in this process. To the interest of this study, previous data from the literature show that the CCL21 and CCL19 and their receptor CCR7 are expressed in breast cancer and may be associated with lymph node metastasis. The aim of this study is to assess the expression of CCL19/CCL21 and their receptor CCR7 in breast cancer tissues and both negative and positive regional lymph nodes using RT-PCR technology . Material and Methods: Formalin fixed paraffin embedded breast cancer specimens obtained from mastectomy were included in the study. RNA isolation using Acidic Phenol method was performed, and then RT-PCR was conducted on both primary tumor and corresponding lymph nodes using specific primers for the studied CCL21/CCL19 chemokines, CCR7 receptor and the positive control GAPDH. Results: The results of this study have revealed a significant positive correlation in mRNA expression in the tumor samples between CCL21 vs.CCL19 (R2=0.9,P-value= 0.02), as well as between CCR7 vs CCL21, and CCR7vs.CCL19 (R2=0.87, P value= 0.04) (R2=0.98,P value= 0.002) respectively. Moreover, there was a significant positive correlation (R2=0.9 , P value= 0.02) in CCL19 expression in primary and secondary tumor. Furthermore, the expression of CCL21 chemokine in negative lymph nodes was more than the expression of it in positive lymph nodes with significant importance (P value = 0.01). The Study of the correlation between CCL21/CCL19 expression in breast tumors and the clinical and pathological parameters, has illustrated a significant correlation between CCL21 vs. CCL19 mRNA expression in breast tumors and triple negative of PR, ER, Her-2 receptors. Conclusion: The results of the study have revealed a potential role of CCR7-CCL21/CCL19 axis in breast cancer. Moreover the results suggest an important role of CCL19 in Lymph nodes metastasis compared to CCL21. Furthermore, the study has showed that CCL21/CCL19 chemokines are expressed in breast tumors with poor prognosis.

Retracted Article: SNHG3 promotes proliferation and invasion by regulating the miR-101/ZEB1 axis in breast cancer.

Background: Dysregulated lncRNA expression contributes to the pathogenesis of human tumors via the lncRNAs functioning as oncogenes or tumor suppressors. Small nucleolar RNA host gene 3 (SNHG3) was demonstrated to be upregulated in breast cancer cells. However, the detailed roles and molecular mechanism of SNHG3 in breast cancer are largely unknown. Methods: The expression of SNHG3, miR-101, and zinc finger E-box-binding protein 1 (ZEB1) in breast cancer tissues and cells was detected using qRT-PCR. The effects of SNHG3 on cell proliferation and invasion were evaluated using MTT, EdU, and cell invasion assays. The protein levels of Ki-67, proliferating cell nuclear antigen (PCNA), matrix metalloproteinase MMP-2, and MMP-9 were analyzed using western blot analysis. A luciferase reporter assay and RNA immunoprecipitation (RIP) were performed to explore the interaction between SNHG3, ZEB1 and miR-101. A subcellular fractionation assay was used to detect the subcellular location of SNHG3. Xenograft tumor experiments were conducted to verify the role and mechanism of SNHG3 in breast cancer in vivo. Results: SNHG3 expression was upregulated in breast cancer tissues and correlated with poor prognosis. SNHG3 knockdown suppressed breast cancer cell proliferation and invasion, which was further demonstrated by high levels of proliferation marker proteins Ki-67/PCNA and metastasis-related proteins MMP-2/MMP-9. Additionally, SNHG3 was located in the cytoplasm of breast cancer cells. SNHG3 functioned as a molecular sponge for miR-101 in breast cancer cells. miR-101 was downregulated in breast cancer tissues and negatively correlated with SNHG3 expression. Moreover, ZEB1, a target of miR-101, was positively regulated by SNHG3 in breast cancer cells. ZEB1 mRNA expression was upregulated in breast cancer tissues and positively correlated with SNHG3 expression. Mechanistically, SNHG3 knockdown suppressed cell proliferation and invasion by upregulation of miR-101 and downregulation of ZEB1 expression in breast cancer cells in vitro and in vivo. Conclusion: SNHG3 promoted proliferation and invasion by regulating the miR-101/ZEB1 axis in breast cancer.

Linc00518 Contributes to Multidrug Resistance Through Regulating the MiR-199a/MRP1 Axis in Breast Cancer

Background/Aims: Long non-coding RNAs (LncRNAs) have been validated to be pivotal mediators in multidrug resistance (MDR) of various cancers. This study aims to explore the roles and molecular mechanisms of linc00518 implicated in chemoresistance in breast cancer. Methods: Expressions of linc00518, miR-199a and MRP1 were evaluated by RT-qPCR or western blot. IC₅₀ values of adriamycin (ADR), vincristine (VCR) and paclitaxel (PTX) were determined by XTT assays and cell apoptosis was assessed by flow cytometry. Luciferase reporter and RIP assays were employed to detect the interaction of linc00518, miR-199a and MRP-1. Results: linc00518 expression increased nearly 2 fold and MRP1 level elevated about 2.5 fold in breast cancer tissues as compared to that in adjacent normal tissues. Also, almost 2 fold upregulation of linc00518 and MRP-1 expressions was observed in MCF-7 cells than in MCF-10A cells. Additionally, linc00518 level was almost 2.5 fold higher and MRP1 level was about 2 fold increased in ADR-resistant MCF-7 cells (MCF-7/ADR) than in parental cell line MCF-7. Linc00518 knockdown enhanced chemosensitivity to ADR, VCR and PTX, and boosted ADR-, VCR- and PTX-induced apoptosis in MCF-7/ADR cells. miR-199a inhibitor conferred chemoresistance to ADR, VCR and PTX in MCF-7/ADR cells, and suppressing miR-199a reversed multi-drug susceptibility induced by linc00518 knockdown. Furthermore, linc00518 could act as a molecular sponge of miR-199a to repress MRP1 expression. MRP1 depletion increased the sensitivity of MCF-7/ADR cells to ADR, VCR and PTX, and this effect was attenuated following miR-199a inhibition or linc00518 overexpression. Also, linc00518 silencing increased ADR-mediated anti-tumor effect in vivo. Conclusions: linc00518 downregulation reduced MDR by regulating miR-199a/MRP1 axis in breast cancer.

The role and clinical significance of the CXCL17-CXCR8 (GPR35) axis in breast cancer

BackgroundChemokine (C-X-C motif) ligand 17 (CXCL17) is the latest member of the chemokine family. However, its function in various cancer types is unknown. The G protein-coupled receptor 35 (GPR35) was identified as the receptor of CXCL17 and named recently as CXCR8. The function of the CXCL17-CXCR8 (GPR35) biological axis in cancer has not been reported. MethodsThe expression of CXCL17 and CXCR8 (GPR35) in breast cancer cell lines and a tissue microarray (TMA) was detected through western blot and immunohistochemistry (IHC). Expression data in IHC were analyzed using clinicopatholigical and survival information. ResultsCXCL17 and CXCR8 (GPR35) were found to be variably expressed in breast cancer cell lines. Both expressed higher in breast cancer tissue than normal adjacent tissue. Although CXCL17 can interact with CXCR8 (GPR35) in breast cancer cells in vitro, the expression correlation between these two markers in breast cancer tissue was not found to be significant. As to clinical significance, CXCR8 (GPR35) expression was found to be significantly associated with advanced histological grade and higher proliferation rate indicated by Ki-67 expression. Although CXCL17 was not found to statistically correlate with any clinicopathological characteristics, it was found to be associated with shorter overall survival and is an independent marker of poor prognosis in breast cancer. In addition, CXCL17 was found to promote proliferation and migration of breast cancer cells in vitro and in vivo. ConclusionsWe investigated the role of the CXCL17-CXCR8 (GPR35) axis in breast cancer for the first time. CXCL17 is a potential oncogene and promising therapeutic target, is an independent biomarker of poor prognosis in patients with breast cancer, and can promote proliferation and migration of breast cancer cells in vitro and in vivo.

MiR-21 is involved in transforming growth factor β1-induced chemoresistance and invasion by targeting PTEN in breast cancer.

Transforming growth factor β1 (TGF-β1) has been associated with poor outcomes in patients with breast cancer. However, the functions and underlying molecular mechanisms of TGF-β1 in breast cancer remain unknown. Therefore, the present study aimed to identify the effects of components of the TGF-β/microRNA (miR-)21/phosphatase and tensin homolog (PTEN) signaling axis in breast cancer. TGF-β1 was identified to upregulate the expression of miR-21, and miR-21 was demonstrated to be significantly upregulated in breast cancer tissues compared with benign proliferative breast disease. In addition, the expression of miR-21 was significantly associated with increased TGF-β1 and clinical characteristics in patients, including tumor grade and lymph node metastasis (all P<0.05). Furthermore, in the breast cancer MCF-7 cell line, TGF-β1 was revealed to induce the expression of miR-21 in a dose- and time-dependent manner. The results of the present study additionally demonstrated that increased miR-21, in response to TGF-β1 signaling, was associated with tumor invasion and chemoresistance in vitro. In addition, suppression of PTEN was mediated by TGF-β1-induced expression of miR-21 in breast cancer cells and using a miR-21 inhibitor revitalized the expression of PTEN. The results of the present study explored the functions of TGF-β1-stimulated expression of miR-21 to suppress the PTEN axis, which promotes breast cancer progression and chemoresistance.

Molecular targeting of the Aurora-A/SMAD5 oncogenic axis restores chemosensitivity in human breast cancer cells.

Although the majority of breast cancers initially respond to the cytotoxic effects of chemotherapeutic agents, most breast cancer patients experience tumor relapse and ultimately die because of drug resistance. Breast cancer cells undergoing epithelial to mesenchymal transition (EMT) acquire a CD44+/CD24-/ALDH1+ cancer stem cell-like phenotype characterized by an increased capacity for tumor self-renewal, intrinsic drug resistance and high proclivity to develop distant metastases. We uncovered in human breast tumor xenografts a novel non-mitotic role of Aurora-A kinase in promoting breast cancer metastases through activation of EMT and expansion of breast tumor initiating cells (BTICs). In this study we characterized the role of the Aurora-A/SMAD5 oncogenic axis in the induction of chemoresistance. Breast cancer cells overexpressing Aurora-A showed resistance to conventional chemotherapeutic agents, while treatment with alisertib, a selective Aurora-A kinase inhibitor, restored chemosensitivity. Significantly, SMAD5 expression was required to induce chemoresistance and maintain a breast cancer stem cell-like phenotype, indicating that the Aurora-A/SMAD5 oncogenic axis promotes chemoresistance through activation of stemness signaling. Taken together, these findings identified a novel mechanism of drug resistance through aberrant activation of the non-canonical Aurora-A/SMAD5 oncogenic axis in breast cancer.

Targeting the CXCR4/CXCL12 axis with the peptide antagonist E5 to inhibit breast tumor progression

Emerging evidence has demonstrated that stromal cell-derived factor 1 (SDF-1) and its cognate receptor CXCR4 have critical roles in tumorigenesis, angiogenesis and metastasis. In this study, we demonstrated the significant inhibitory effects of a novel chemically synthetic peptide (E5) on the CXCR4/CXCL12 axis in breast cancer both in vitro and in vivo. E5 was capable of specifically binding to the murine breast cancer cell line 4T1, remarkably inhibiting CXCL12- or stromal cell (MS-5)-induced migration, and adhesion and sensitizing 4T1 cells to multiple chemotherapeutic drugs. Furthermore, E5 combined with either paclitaxel or cyclophosphamide significantly inhibited tumor growth in a breast cancer model. Mechanistic studies implied that E5 can inhibit the expression of CXCR4 to block the CXCL12-mediated recruitment of endothelial progenitor cells and repress CXCR4 downstream of the Akt and Erk signaling pathway, which are involved in tumor angiogenesis and progression. Further pharmacokinetic evaluation suggested that E5 has an acceptable stability, with a half-life of 10 h in healthy mice. In conclusion, E5 demonstrates a promising anti-tumor effect and could be a potential chemotherapeutic sensitizer to improve current clinical breast cancer therapies.

The lncRNA NEAT1 facilitates cell growth and invasion via the miR-211/HMGA2 axis in breast cancer

Long non-coding RNAs play a significant role in cancer metastasis. Studies have demonstrated that LncRNA NEAT1 promotes cancer progression. We aimed to explore whether NEAT1 regulated growth and invasion in breast cancer cells. We provided evidence that lncRNA NEAT1 was up-regulated in breast cancer cell lines and tissues. NEAT1 promoted invasion through inducing Epithelial-mesenchymal transition (EMT) and NEAT1 played a role in 5-fluorouracil (5-FU) resistance. In addition, we revealed a reciprocal repression between NEAT1 and miR-211. Furthermore, the EMT-inducer HMGA2 was identified as a down-stream target of miR-211. LncRNA NEAT1 induced EMT and 5-FU resistance through the miR-211/HMGA2 axis. Our findings suggest that lncRNA NEAT1 could be a new diagnostic biomarker and therapy target for breast cancer.

Abstract 2348: Targeting the p27kip1/cdk4/cdk2/Rb axis in breast cancer using a peptidomimetic of Brk’s SH3 domain

Abstract Purpose: Cyclin D-cdk4 (DK4) has been a highly sought after therapeutic target because it drives cancer proliferation in a majority of human tumors. We have explored the clinical utility of a recently discovered mechanism of cell cycle control exerted on DK4 by p27Kip1 and its activator, the Breast tumor Related Kinase (Brk), in predicting responsiveness to therapy and as a new target for treatment. Although known as a DK4 assembly factor and cdk2 inhibitor, p27 also acts as a DK4 ON/OFF “switch.” Tyrosine (Y) phosphorylation of p27 (pY) by Brk gatekeeps both ATP binding and CAK phosphorylation of cdk4’s T loop, essential for DK4 activation. This function is restricted to cdk4: p27’s association with cdk2, whether Y phosphorylated or not, appears to be inhibitory. However, in vivo Y phosphorylated p27 is a target for cdk2-dependent ubiquitin-mediated degradation, reducing p27’s association with cdk2, indirectly activating this complex. We showed that blocking p27 pY inactivates cdk4 directly AND cdk2 indirectly, and thus represents a novel way to block cancer cell proliferation. pY also serves as a predictive biomarker of cdk4 activity and tumor response. Methods: We used a small peptide, ALT, which contains a portion of Brk’s SH3 domain. ALT binds to p27, blocks Brk’s association and ability to phosphorylate p27, inhibiting cdk4 and increasing p27’s ability to inhibit cdk2. We engineered a lipid-based nanoparticle delivery vehicle (NP-ALT), permitting us to test ALT as a first generation therapeutic in breast cancer cell lines that were both responsive and non-responsive to cdk4i therapy. ALT was also used with Palbociclib to determine if combination therapy reduced drug resistance. We developed a dual IHC assay for p27 and pY, which we used to analyze paraffin-embedded, archival human tumor samples, to determine whether we could pinpoint patients who would have responded to cdk4 inhibition therapy. Results: NP-ALT blocks pY, cdk4 and cdk2 activity, and proliferation in both Palbociclib sensitive and resistant cell lines. As a dual therapy, ALT treatment synergized with Palbociclib to arrest cells for &amp;gt;30 days, increased senescence, and in animal models caused tumor regression instead of just slowing tumor growth as seen with Palbociclib alone. Analysis of human cancer, obtained from archival sources, demonstrated that pY is never detected in quiescent benign mammary tissue, but is detected in about half of the advanced ER/PR+/Her2- tumors analyzed, and using explant culture techniques, we were able to stratify pY with Palbociclib response. Conclusion: Use of an Brk SH3 based peptide (NP-ALT) has proven effective in blocking p27 pY, inhibiting both cdk2 and cdk4, inducing senescence and increased durability. pY levels correlate with Palbociclib sensitivity in low, moderate and non-responders, suggesting that this may be a biomarker highlighting responsiveness to cdk4i therapy. Citation Format: Stacy W. Blain, Jason Quinones, Priyank Patel, Vladislav Tsiperson, Susan Gottesman, Jonathan Somma, Yun Wu. Targeting the p27kip1/cdk4/cdk2/Rb axis in breast cancer using a peptidomimetic of Brk’s SH3 domain [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2348. doi:10.1158/1538-7445.AM2017-2348

Abstract 3557: miR-155 positively regulates glucose metabolism via PI3K p85&amp;lt;alpha&amp;gt;-FOXO3a-cMYC axis in breast cancer

Abstract Breast cancer is the most common cancer for women worldwide. Although the oncogenic roles of miR-155 in cancer have been reported, the metabolic function of miR-155 in breast cancer has not been fully elucidated. In this study, we have investigated how the energy metabolic shift occurs after a genetic inactivation or knockdown of miR-155. To this end, we performed metabolic profiling of the miR-155ko/ko or miR-155+/ko primary cancer cells, obtained from mouse breast cancer model. We found, in the absence of miR-155, less glucose uptake and glycolysis in tumor cells. Mechanistically, we revealed PIK3R1(Phosphoinositide-3-Kinase, Regulatory Subunit1, p85&amp;lt;alpha&amp;gt;) and FOXO3a (Forkhead transcription factor of the O class 3a) are major targets that trigger the metabolic shift. Furthermore, we showed cMYC level was consequently decreased in the absence of miR-155 that results in the down-regulation of proteins playing in glucose uptake and Glycolysis. This finding is further confirmed in mouse allograft model. Finally, we show the miR-155 expression is positively correlates with either energy metabolite levels or standardized uptake values (SUV) of fluoro-deoxy glucose (FDG)-PET Images in triple negative breast tumors. Taken together, our study demonstrates a novel mechanism by which the miR-155 controls energy metabolism in breast cancer, through PI3K p85&amp;lt;alpha&amp;gt;-FOXO3a-cMYC axis. Citation Format: Sinae Kim, Eunji Lee, Suhwan Chang. miR-155 positively regulates glucose metabolism via PI3K p85&amp;lt;alpha&amp;gt;-FOXO3a-cMYC axis in breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3557. doi:10.1158/1538-7445.AM2017-3557

Co-targeting the HER and IGF/insulin receptor axis in breast cancer, with triple targeting with endocrine therapy for hormone-sensitive disease

Interactions between HER2, estrogen receptor (ER), and insulin-like growth factor I receptor (IGF1R) are implicated in resistance to monotherapies targeting these receptors. We have previously shown in pre-clinical studies synergistic anti-tumor effects for co-targeting each pairwise combination of HER2, IGF1R, and ER. Strikingly, synergy for HER2/IGF1R targeting occurred not only in a HER2+model, but also in a HER2-normal model. The purpose of the current study was therefore to determine the generalizability of synergistic anti-tumor effects of co-targeting HER2/IGF1R, the anti-tumor activity of triple-targeting HER2/IGF1R/ER in hormone-dependent cell lines, and the effect of using the multi-targeting drugs neratinib (pan-HER) and BMS-754807 (dual IGF1R/insulin receptor). Proliferation and apoptosis assays were performed in a large panel of cell lines representing varying receptor expression levels. Mechanistic effects were studied using phospho-protein immunoblotting. Analyses of drug interaction effects were performed using linear mixed-effects regression models. Enhanced anti-proliferative effects of HER/IGF-insulin co-targeting were seen in most, though not all, cell lines, including HER2-normal lines. For ER+lines, triple targeting with inclusion of anti-estrogen generally resulted in the greatest anti-tumor effects. Double or triple targeting generally resulted in marked increases in apoptosis in the sensitive lines. Mechanistic studies demonstrated that the synergy between drugs was correlated with maximal inhibition of Akt and ERK pathway signaling. Dual HER/IGF-insulin targeting, and triple targeting with inclusion of anti-estrogen drugs, shows striking anti-tumor activity across breast cancer types, and drugs with broader receptor specificity may be more effective than single receptor selective drugs, particularly for ER- cells.

Retracted: NEAT1 induces epithelial-mesenchymal transition and 5-FU resistance through the miR-129/ZEB2 axis in breast cancer.

The above article from FEBS Letters, published online on 1 November 2016 in Wiley Online Library (http://wileyonlinelibrary.com), has been withdrawn by agreement between the Journal Managing Editor, Felix Wieland, and John Wiley & Sons Ltd., on behalf of Federation of European Biochemical Societies. The withdrawal has been agreed following an investigation by the Journal's Editorial Office that found that the data in Figures 4C and 4E appears to have been manipulated.

Progress with palbociclib in breast cancer: latest evidence and clinical considerations.

Deregulation of the cell cycle is a hallmark of cancer, and research on cell cycle control has allowed identification of potential targets for anticancer treatment. Palbociclib is a selective inhibitor of the cyclin-dependent kinases 4 and 6 (CDK4/6), which are involved, with their coregulatory partners cyclin D, in the G1-S transition. Inhibition of this step halts cell cycle progression in cells in which the involved pathway, including the retinoblastoma protein (Rb) and the E2F family of transcription factors, is functioning, although having been deregulated. Among breast cancers, those with functioning cyclin D-CDK4/6-Rb-E2F are mainly hormone-receptor (HR) positive, with some HER2-positive and rare triple-negative cases. Deregulation results from genetic or otherwise occurring hyperactivation of molecules subtending cell cycle progression, or inactivation of cell cycle inhibitors. Based on results of randomized clinical trials, palbociclib was granted accelerated approval by the US Food and Drug Administration (FDA) for use in combination with letrozole as initial endocrine-based therapy for metastatic disease in postmenopausal women with HR-positive, HER2-negative breast cancer, and was approved for use in combination with fulvestrant in women with HR-positive, HER2-negative advanced breast cancer with disease progression following endocrine therapy. This review provides an update of the available knowledge on the cell cycle and its regulation, on the alterations in cyclin D-CDK4/6-Rb-E2F axis in breast cancer and their roles in endocrine resistance, on the preclinical activity of CDK4/6 inhibitors in breast cancer, both as monotherapy and as partners of combinatorial synergic treatments, and on the clinical development of palbociclib in breast cancer.

Abstract B119: Characterization of a phosphatidylserine, TAM receptor (Tyro3, Axl, Mertk), PDL1 axis in breast cancer

Abstract Tyro3, Axl and Mer (TAMs) are three homologous receptor tyrosine kinases that bind vitamin K-dependent endogenous ligands, Protein S (PROS1) and Gas6, and act as bridging molecules to promote PS-mediated clearance of apoptotic cells (efferocytosis). In recent years, evidence has accumulated that TAMs are overexpressed in a wide array of tumor types, whereby the level of expression correlates with the tumor grade and the emergence of chemo and radio resistance to targeted therapeutics. TAMs have also been implicated as inhibitory receptors on myeloid-derived cells that suppress anti-tumor immunity. In addition to TAM overexpression, externalized PS is also concomitantly up-regulated in the tumor microenvironment, suggesting that PS and PS receptors might act as immune checkpoint inhibitors. To better understand the biology of TAMs, and the specificity of interaction between TAMs and PS, we generated chimeric TAM reporter cell lines comprised of the extracellular domains of each TAM fused to the intracellular domains of the IFNR1, as well as cell lines stably expressing full-length native TAMs. Using these systems, we found that each TAM receptor has a unique pattern of activation by GAS6 and PROS1, as well as unique dependency for PS on apoptotic cells, PS liposomes, and exosomes. Interrogating epithelial cells that express WT TAMs, we also observed that each TAM showed differential capacity for efferocytosis, AKT-mediated chemo-resistance, and their ability to up-regulate the immune checkpoint inhibitory ligand PD-L1 on breast cancer cells. Functionally, TAM-mediated efferocytosis and PD-L1 up-regulation could be partially blocked by PS targeted antibodies 11.31 and bavituximab, suggesting the existence of a PS/PS-R (TAM-receptor)/PD-L1 axis that drives immune escape in solid cancers. These studies demonstrate that, despite their similarities, Tyro3, Axl and Mertk are likely to perform distinct functions in both immune-regulation and the recognition and removal of apoptotic cells. Finally, these studies provide a rationale for combinatorial therapeutics targeting PS, TAM, and PD-L1 as immune checkpoint inhibitors in the treatment of cancer. Citation Format: Canan Kasikara, Sushil Kumar, Ke Geng, Viral Davre, Cyril Empig, Bruce Freimark, Michael Gray, Kyle Schlunegger, Jeff Hutchins, Sergei V. Kotenko, Raymond B. Birge. Characterization of a phosphatidylserine, TAM receptor (Tyro3, Axl, Mertk), PDL1 axis in breast cancer [abstract]. In: Proceedings of the Second CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; 2016 Sept 25-28; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(11 Suppl):Abstract nr B119.