Impact of MYC on metabolic reprogramming, cellular energetics, and tumorigenesis in Breast cancer

Co-amplification and co-overexpression of ErbB2 and Grb7 are frequently found in various cancers, including breast cancer. Biochemical and functional correlations of the two molecules have identified Grb7 to be a pivotal mediator downstream of ErbB2-mediated oncogenesis. However, it remains largely unknown how Grb7 is involve in the ErbB2-mediated tumorigenesis. In this study, we show that Grb7-mediated cell proliferation and growth are essential for the tumorigenesis that occurs in ErbB2-Grb7-overexpressing breast cancer cells. Intrinsically, EGF-induced de novo Grb7 tyrosine phosphorylation/activation recruits and activates Ras-GTPases and subsequently promotes the phosphorylation of ERK1/2, thereby stimulating tumor growth. Furthermore, we also found the anti-tumor effect could be synergized by co-treatment with Herceptin plus Grb7 knockdown in Sk-Br3 breast cancer cells. Our findings illustrate an underlying mechanism by which Grb7 promotes tumorigenesis through the formation of a novel EGFR-Grb7-Ras signaling complex, thereby highlighting the potential strategy of targeting Grb7 as an anti-breast cancer therapy.

BackgroundEmerging evidence have illustrated the vital role of long noncoding RNAs (lncRNAs) long intergenic non-protein coding RNA 00511 (LINC00511) on the human cancer progression and tumorigenesis. However, the role of LINC00511 in breast cancer tumourigenesis is still unknown. This research puts emphasis on the function of LINC00511 on the breast cancer tumourigenesis and stemness, and investigates the in-depth mechanism.MethodsThe lncRNA and RNA expression were measured using RT-PCR. Protein levels were measured using western blotting analysis. CCK-8, colony formation assays and transwell assay were performed to evaluate the cell proliferation ability and invasion. Sphere-formation assay was also performed for the stemness. Bioinformatic analysis, chromatin immunoprecipitation (ChIP) and luciferase reporter assays were carried to confirm the molecular binding.ResultsLINC00511 was measured to be highly expressed in the breast cancer specimens and the high-expression was correlated with the poor prognosis. Functionally, the gain and loss-of-functional experiments revealed that LINC00511 promoted the proliferation, sphere-formation ability, stem factors (Oct4, Nanog, SOX2) expression and tumor growth in breast cancer cells. Mechanically, LINC00511 functioned as competing endogenous RNA (ceRNA) for miR-185-3p to positively recover E2F1 protein. Furthermore, transcription factor E2F1 bind with the promoter region of Nanog gene to promote it transcription.ConclusionIn conclusion, our data concludes that LINC00511/miR-185-3p/E2F1/Nanog axis facilitates the breast cancer stemness and tumorigenesis, providing a vital insight for them.

LncRNA cancer susceptibility candidate 15 accelerates the breast cancer cells progression via miR-153–3p/KLF5 positive feedback loop

The aim of this study was to investigate the relationship of the mutations of leptin receptor gene exon 4, exon 6, exon9, and exon20 with the tumorigenesis of breast cancer. Genomic DNA was extracted from breast cancer tissues of 155 patients, benign lesions of 56 patients and normal tissues and blood samples from 100 health control subjects. The leptin receptor genes were assayed with polymerase chain reaction (PCR) amplification and direct sequence analysis. Nucleotide substitutions no mutations were found at exon 4, and nucleotide substitutions occurred at codon 1029 in exon 9, no significant difference among the three groups (P = 0.574). The nucleotide substitutions at codon 668 in exon 6 resulted in Gln223Arg polymorphisms. The occurring frequencies of GG, GA, AA in breast cancer, breast benign lesions tissues and health tissues control group were 70.9% and 17.4%, 12.3%; 80.4%, 14.3% and 5.4%; and 81.0%, 16.0%, and 3.0%, respectively. Alleles of G and A in the three groups were 79.1% and 20.8%, 87.5% and 12.5%, and 89.0% and 11.0%, respectively. Compared the Gln223Arg genotype with the three allele groups, there were significant differences (χ(2) = 16.11, P < 0.005 and χ(2) = 11.41, P < 0.01), respectively. The nucleotide substitutions at codon 3057 in exon 20 resulted in Pro1019Pro polymorphisms. The occurrence frequencies of GG, GA, AA in the breast cancer, benign disease and health control groups were 11.6%, 30.3% and 56.1%; 32.1%, 44.0% and 28.5%; and 32.0%, 45.0% And 23.0%, respectively. Alleles of G and A in the three groups were 26.8% and 73.2%, 51.8% and 48.2%, and 54.5% and 45.5%, respectively. There are significant differences among the three groups (χ(2) = 6.56, P < 0.03 and χ(2) = 5.45, P < 0.05), respectively. Nucleotide substitutions occurred at relatively high frequencies at exon 6 and exon 20 in obese and overweight breast cancer patients compared with those in normal weight breast cancer patients, there were significant differences (P < 0.05 and P < 0.01). Our findings show that there is no relationship between the variations of leptin receptor gene exon 9 and tumorigenesis of breast cancer. The variation rate of leptin receptor gene exon 6 and exon 20 are significantly increased in the obese and overweight breast cancer patients.

Role of regulatory miRNAs of the Wnt/ β-catenin signaling pathway in tumorigenesis of breast cancer.

Simple SummaryBreast cancer is the most prevalent cancer in women worldwide, and it exhibits a growing incidence. An increasing number of studies showed the complex bidirectional regulation between breast cancer and adjacent cancer-associated adipocytes. The present review summarizes the mechanisms of cancer-associated adipocyte formation in the breast cancer tumor microenvironment and the effect of cancer-associated adipocytes on the tumorigenesis, progression, and metastasis of breast cancer. We focused on the therapeutic resistance of breast cancer caused by cancer-associated adipocytes and potential strategies targeting cancer-associated adipocytes in breast cancer treatment.Adipocytes are the main components in breast tissue, and cancer-associated adipocytes (CAAs) are one of the most important components in the tumor microenvironment of breast cancer (BC). Bidirectional regulation was found between CAAs and BC cells. BC facilitates the dedifferentiation of adjacent adipocytes to form CAAs with morphological and biological changes. CAAs increase the secretion of multiple cytokines and adipokines to promote the tumorigenesis, progression, and metastasis of BC by remodeling the extracellular matrix, changing aromatase expression, and metabolic reprogramming, and shaping the tumor immune microenvironment. CAAs are also associated with the therapeutic response of BC and provide potential targets in BC therapy. The present review provides a comprehensive description of the crosstalk between CAAs and BC and discusses the potential strategies to target CAAs to overcome BC treatment resistance.

Tumor cells reprogram their energy metabolism patterns to meet the needs of rapid growth and metastasis. The underlying mechanisms of long noncoding RNAs (lncRNAs) in glucose metabolism remodeling in breast cancer (BC) are still not well understood. Herein, the expression of a tumorigenic lncRNA, LINC01094 are demonstrated that, is significantly increased in BC tissues and is associated with poorer patient survival. METTL14‐mediated m6A modification stabilized LINC01094 by recruiting the reader protein IGF2BP2, which contributed to the upregulation of LINC01094 expression in BC. Gain‐ and loss‐of‐function assays validated that LINC01094 triggered a switch in glucose metabolism from mitochondrial respiration to glycolysis, promoting BC progression both in vitro and in vivo. LINC01094 promoted the dimeric assembly and nuclear translocation of PKM2 by acting as a “molecular scaffold” for the PKM2/JMJD5 complex. This, in turn, facilitated energy metabolic reprogramming and cell proliferation induced by HIF1‐α/β‐catenin. Furthermore, the therapeutic potential of LINC01094 is evaluated through the administration of the PKM2 activator TEPP‐46 in mouse xenografts. These findings highlight the critical roles of LINC01094 in cellular glucose metabolism and tumorigenesis in BC, suggesting that it is a potential therapeutic target.

BACKGROUNDIt has been reported that the sympathetic nervous system and associated neurotransmitters (NTs) play a pivotal role in driving breast cancer (BC) tumorigenesis and metastasis, however, comprehensive characterization of these pathways in BC is lacking. The purpose of this study was to retrospectively characterize NTs and neuronal signaling (NTNS) gene alterations in a large real-world BC cohort. METHODS A total of 6464 BC tumors were analyzed by next generation sequencing (NextSeq, 592 genes and WES, NovaSEQ, 720 genes) and whole transcriptome sequencing (WTS, NovaSeq) at Caris Life Sciences. Gene set variation analysis (GSVA) scores were calculated (positive: higher gene expressions in a selected gene set compared to genes outside that gene set in each tumor specimen, vice versa for negative) to assess expression of major NTNS genes, including GABA, nicotinic (NIC), muscarinic (MUS), dopamine (DA), reelin (RELN), and glial cell line-derived neurotrophic factor (GDNF). GSVA scores were compared by histologic subtype, primary or metastatic site, and hormone receptor (HR) and HER2 status with corrected Wilcoxon-Mann-Whitney testing. All significance levels were p&amp;lt;0.01. RESULTS The 6464 BC specimens in this cohort included 2520 primary sites and 3944 metastasis (mets) (liver: 1012; lymph node: 714; bone: 575; lung: 420; brain: 196). Predictive biomarker status in this cohort was HR+/HER2-: 3705; HR+/HER2+: 238; HR-/HER2+: 189; TNBC: 1654. Invasive ductal carcinomas (IDC) were the most common histologic subtype and demonstrated significantly higher GSVA scores for RELN and NIC pathways with respect to invasive lobular carcinomas (ILC) (Table). TNBC tumors had significantly higher enrichment overall (GABA, -0.04 vs -0.14; RELN, -0.05 vs -0.31; DA, -0.03 vs -0.08; MUS, 0.13 vs -0.16; NIC, 0.01 vs -0.12; and GDNF, 0.04 vs -0.04). HR-/HER2+ had significantly higher scores in GABA, -0.04 vs -0.14; RELN, -0.03 vs -0.31; MUS, 0.12 vs -0.16; and NIC, -0.01 vs -0.12 genes. Brain mets had significantly enriched pathway scores for GABA, 0.30 vs -0.13; MUS, 0.15 vs -0.08; and NIC, 0.13 vs -0.09 compared to primary tumors. Similarly, GABA,0.09 vs -0.13; DA, 0.07 vs -0.05; MUS, 0.17 vs -0.08; and NIC, 0.02 vs -0.09 pathways were enriched in bone mets compared to those from primary tumors. CONCLUSION Our results demonstrate that NTNS pathways are significantly enriched in IDC, TNBC tumors, and particularly in brain and bone mets. Our data advance the current understanding of the role of NTNS pathways in BC tumorigenesis and metastasis. Further investigation on genetic. determinants and signaling alternations associated with the observed NTNS pathway deregulation is warranted and could inform the development of novel therapeutic strategies. Significant comparisons with Bonferroni corrected p values are shown with an asterisk. Citation Format: Irene Kang, Krutika Deshpande, Sarah Persing, Jun Yin, Joanne Xiu, Wolfgang Michael Korn, Jia Zeng, Evanthia T Roussos-Torres, Janice Lu, Darcy Spicer, Stephen F Sener, Antoinette R Tan, Ashley Sumrall, David SB Hoon, Cynthia X Ma, Carey K Anders, Heather L McArthur, Reva Basho, Heinz-Josef Lenz, Josh Neman. Comprehensive characterization of neurotransmitters and neuronal signaling gene alterations in invasive breast cancers [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr PD6-06.

Leukemia inhibitory factor (LIF) is a multi-functional cytokine protein. The role of LIF in tumorigenesis is not well-understood. Here, we found that LIF promotes tumorigenesis and metastasis of breast cancer. LIF promotes cell proliferation and anchorage-independent growth of breast cancer cells in vitro, and the growth of xenograft breast tumors in vivo. LIF also promotes invasion and migration of breast cancer cells in vitro and metastasis of breast cancer in vivo. We found that LIF activates the AKT-mTOR signaling pathway to promote tumorigenesis and metastasis of breast cancer. Inhibiting the AKT activity can largely block the activation of the mTOR pathway by LIF, suggesting that LIF activates the mTOR pathway through AKT. Inhibiting the AKT activity as well as inhibiting the mTOR activity largely block the promoting effect of LIF on tumorigenesis and metastasis. Furthermore, overexpression of LIF is significantly associated with a poorer relapse free survival in breast cancer patients. Taken together, our data strongly suggest that LIF plays an important role in the tumorigenesis and metastasis of breast cancer, and could be an important prognostic marker for breast cancer.

RP11-480I12.5-004 Promotes Growth and Tumorigenesis of Breast Cancer by Relieving miR-29c-3p-Mediated AKT3 and CDK6 Degradation

BackgroundHematological and neurological expressed 1 (HN1) is upregulated in many tumors, but the role of HN1 in breast cancer progression and its regulatory mechanism have not been well understood.MethodsTo study the role of HN1 in the initiation and progression of breast cancer, we examined HN1 levels in breast cancer cells and tissues and analyzed the relationship between HN1 levels and patient survival. We used mammosphere formation assay, side population analysis, wound healing assay, transwell assay, soft agar formation assay, and xenografted tumor model to determine the effect of HN1 on the expansion of breast cancer stem cells, and the migration, invasion and tumorigenesis of breast cancer. To determine whether HN1 regulates MYC, we used quantitative real-time PCR and Western blot analysis to assess the expression of MYC and their targeted genes to determine the phenotype caused by knockdown of MYC in breast cancer cell with HN1 overexpression.ResultsIn this study, we found that HN1 was upregulated in breast cancer tissues. Patients with high levels of HN1 expression had significantly shorter survival than those with low HN1 expression. In breast cancer cell line, ectopic overexpression of HN1 not only promoted the expansion of breast cancer stem cells, but also promoted cell migration, invasion, and tumorigenesis, while knockdown of HN1 reduced these effects. Furthermore, there was a positive correlation between MYC (also known as c-MYC) level and HN1 level, mechanism analysis suggested HN1 promoted the expression of MYC and its targeted genes like CDK4, CCND1, p21, CAV1, and SFRP1. Downregulation of MYC abrogated the effect of HN1 overexpression in breast cancer cell lines.ConclusionTaken together, these data reveal that HN1 promotes the progression of breast cancer by upregulating MYC expression, and might be a therapeutic target for breast cancer.

Sialyltransferases are enzymes that play a crucial role in regulating cancer progression by modifying glycoproteins through sialylation. In particular, the ST3 beta-galactoside alpha-2,3-sialyltransferase 4 (ST3GAL4) enzyme is known to be upregulated in breast cancer, but its specific biological functions have not been fully understood. This study aimed to investigate the impact and mechanisms of ST3GAL4 on aerobic glycolysis in breast cancer. We examined ST3GAL4 expression in tumor tissue samples and breast cancer cell lines and also manipulated ST3GAL4 expression in breast cancer cells using lentivirus transduction. The study evaluated cellular processes such as cell viability, cell cycle progression, and aerobic glycolysis by measuring parameters like extracellular acidification rate, glucose uptake, lactate production, and lactate dehydrogenase A (LDHA) expression. We found that ST3GAL4 expression was consistently increased in tumor tissues and breast cancer cell lines. High ST3GAL4 expression was associated with a poor prognosis for patients with breast cancer. Inhibiting ST3GAL4 expression decreased cell viability, disrupted cell cycle progression, and reduced aerobic glycolysis and LDHA expression. Furthermore, suppressing ST3GAL4 expression in animal models reduced tumor growth and cell proliferation. Conversely, overexpressing ST3GAL4 promoted cell viability and cell cycle progression, but these effects were reversed when an inhibitor of aerobic glycolysis was used. The study provided evidence in cells and animal models that ST3GAL4 promotes tumorigenesis in breast cancer by enhancing aerobic glycolysis. These findings suggest that targeting ST3GAL4 may be a potential strategy for the treatment of breast cancer.

Treatment of triple-negative breast cancer (TNBC) remains challenging due to a lack of effective targeted therapies. Dysregulated glucose uptake and metabolism are essential for TNBC growth. Identifying the molecular drivers and mechanisms underlying the metabolic vulnerability of TNBC is the key to exploiting dysregulated cancer metabolism for therapeutic applications. Mitogen-inducible gene-6 (MIG-6) has long been thought as a feedback inhibitor that targets activated EGFR and suppresses the growth of tumors driven by constitutive activated mutant EGFR. Here, our bioinformatics and histological analyses uncovered that MIG-6 is upregulated in TNBC and that MIG-6 upregulation is positively correlated with poorer clinical outcomes in TNBC. Metabolic arrays and functional assays revealed that MIG-6 drives glucose metabolism reprogramming toward glycolysis. We found that hypoxia-induced MIG-6 promotes HIF1α protein stabilization and the subsequent upregulation of GLUT1 and other HIF1α-regulated glycolytic genes, substantiating the comprehensive regulation of MIG-6 in glucose metabolism. Moreover, our animal studies demonstrated that MIG-6 regulates GLUT1 expression in tumors and subsequent tumor growth in vivo. Collectively, this work reveals that MIG-6 is a novel prognosis biomarker, metabolism regulator, and molecular driver of TNBC. Citation Format: Jiabei He, Chien-Feng Li, Hong-Jen Lee, Dong-Hui Shin, Bruno De Carvalho, Chia-Hsin Chan. Hypoxia-induced MIG-6 promotes glucose metabolic reprogramming and tumorigenesis in triple-negative breast cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1452.

Background: The main cause of cancer deaths amongst women breast cancer remains a clinical and social challenge, and a serious public health problem. On a worldwide level, it continues to be a devastating disorder.BECN1 is a tumor suppressor gene implicated in the initiation of autophagy. It encodes beclin-1 protein that inhibits cancer growth. There is wide disputation concerning its role in initiation, promotion of tumor and predictive importance of autophagic molecules. Transforming growth factor β (TGF-β) induces process of epithelial-mesenchymal transition (EMT) keeping, epithelial cells more motile and invasive resulting in cancer progression and metastasis.&#x0D; Aim: Detection of beclin-1 expression level in metastatic and non-metastatic breast cancer patients and study its role in tumorigenesis of breast cancer through attainable association with the inflammatory cytokine, TGF-β.&#x0D; Methods: Expression levels of beclin-1 and TGF-β were assessed in 70 breast cancer female patients and 20 controls using quantitative real-time PCR.&#x0D; Results: Beclin-1 expression levels as well as TGF-β were significantly higher in metastatic breast cancer patients and non-metastatic patients compared to controls. Positive correlation was found between beclin-1 expression level and TGF-β expression level in breast cancer patients.&#x0D; Conclusion: Our results indicated that over-expression of both beclin-1 and TGF-β was associated with aggressive clinical outcomes of breast cancer patients and tumor growth. These findings suggest that beclin-1 and TGF-β are associated with tumorigenesis of breast cancer.

CircBRWD3 is a newly discovered circRNA, and its potential function has not been probed. Here, we aimed to molecularly dissect the role of circBRWD3 in the tumorigenesis and progression of breast cancer (BC). qRT-PCR analysis revealed that circBRWD3 expression was dramatically upregulated in BC tissues, a feature that was positively correlated with the poor prognosis of patients with BC. CircBRWD3 knockdown repressed cell proliferation and metastasis, while promoting cell apoptosis in vitro. Consistently, an in vivo circBRWD3 deficiency model exhibited suppressed tumor metastasis and oncogenesis. On the other hand, circBRWD3 overexpression promoted cancer cell activity and tumorigenesis. Further, mechanistic studies elucidated that circBRWD3 sponged both miR-142-3p and miR-142-5p to modulate RAC1 expression, which subsequently activated the RAC1/PAK1 signaling to facilitate the tumorigenesis and progression of BC. Moreover, we discovered that EIF4A3 facilitated circBRWD3 expression by targeting the upstream of BRWD3 pre-mRNA. In conclusion, our study reveals that circBRWD3 facilitates BC tumorigenesis by regulating the circBRWD3/miR-142-3p_miR-142-5p /RAC1/PAK1 axis. In addition, circBRWD3 expression is positively regulated by an RNA-binding protein, EIFA3. Our results provide valuable scientific data for early diagnosis and therapy for breast cancer patients.