Regulation Of Breast Cancer Progression Research Articles

CircRASSF2 acts as a prognostic factor and promotes breast cancer progression by modulating miR-1205/HOXA1 axis

ABSTRACT Circular RNA (circRNA), a recently identified endogenous non-coding RNA molecule, regulates gene expression in mammals. At the current stage, the expression and function of circRASSF2 in breast cancer (BC) have not been clarified. According to our study, it is found that circRASSF2 sequences contain miR-1205 binding sites, and Homeobox gene A1 (HOXA1) is the target gene of miR-1205. Besides, the clinical observations and histopathologic study reveal that the expression of circRASSF2 increased to a significant extent in BC tissues and serum. Additionally, it is found that circRASSF2 expression had a positive correlation with distant metastasis, lymph node metastasis, TNM stage, differentiation and tumor size, and that overall survival (OS) and progression-free survival (PFS) of circRASSF2 high expression BC patients were inferior to those with low circRASSF2 expression. In vitro study, an overt decrease was detected in the proliferation, clone formation ability, migration and invasion of breast cancer cells in cells when circRASSF2 was knocked down. We confirmed the direct interaction between circRASSF2, miR-1205 and HOXA1 by a dual luciferase reporter system. Additionally, our study revealed that over-expression of miR-1205 decreased HOXA1 protein expression, and HOXA1 protein expression decreased when circRASSF2 were knocked down, and when miR-1205 expression was inhibited, HOXA1 expression was significantly increased. In conclusion, our study suggests that circRASSF2 regulates BC progression through the miR-1205/HOXA1 pathway. Our findings suggest the prospect of circRASSF2 serving as therapeutic target as such to cure BC patients.

CircSLC8A1 sponges miR-671 to regulate breast cancer tumorigenesis via PTEN/PI3k/Akt pathway

Breast cancer is the most frequently diagnosed and the leading cause of cancer-related deaths in women worldwide. However, the role of circSLC8A1 in breast cancer remains elusive. Herein, a cohort of 77 breast tumors and paired adjacent normal mammary tissues were collected. We demonstrated that circSLC8A1 was significantly down-regulated in breast cancer tissues and cell lines, of which expression was negatively correlated with clinical severity and dismal prognosis. Overexpression of circSLC8A1 suppressed cell proliferation, migration and invasion in vitro, and inhibited tumor growth in vivo. CircSLC8A1 directly targeted miR-671 to execute tumor suppressive activities via regulating PI3k/Akt signaling. Krüppel-like factor 16 (KLF16), a transcriptional activator of PTEN, was identified as a target of miR-671. Furthermore, circSLC8A1 could sponge miR-671 to suppress breast tumor growth via PTEN/PI3k/Akt signaling in vivo. In summary, circSLC8A1/miR-671 regulates breast cancer progression through PTEN/PI3k/Akt signaling, which may provide efficient therapeutic target for this devastating cancer.

LncRNA SPINT1-AS1 promotes breast cancer proliferation and metastasis by sponging let-7 a/b/i-5p

BackgroundA growing number of studies have shown that long non-coding RNAs (lncRNAs) play an important role in the occurrence and development of tumors. In this study, we explored the function and molecular mechanism of lncRNA SPINT1-AS1 in breast cancer progression. MethodsA total of 30 patients and 25 healthy controls were enrolled to detect the expression of SPINT1-AS1 in the serum by RT-qPCR. CCK-8 assay, clone formation assay, EdU assay, Transwell assay, Flow cytometry for apoptosis assay and wound healing assays were used to explore the effects of SPINT1-AS1 on the proliferation and migration of breast cancer cells. Bioinformatics analysis were used to enrich the downstream target genes and related pathways of miRNAs interacting with SPINT1-AS1, construct a competitive endogenous RNA (ceRNA) network diagram. ResultsSPINT1-AS1 is up-regulated in the serum of breast cancer patients and breast cancer cell lines. The proliferation and migration ability of breast cancer cells were decreased significantly after SPINT1-AS1 knockdown, and it may inhibit its expression by sponging miR-let-7a/b/i-5p, thereby promoting breast cancer progression. ConclusionsSPINT1-AS1 can promote the proliferation and migration of breast cancer cells by regulating miR-let-7a/b/i-5p, suggesting that it may be an important regulator of breast cancer progression.

Methylation-Mediated Silencing of MicroRNA-497 Promotes Breast Cancer Progression Through Up-Regulation of Mucin1.

BackgroundPotential anti-tumor effects of microRNA-497 (miR-497) have been highlighted in various malignancies including breast cancer. However, little is known about the function of miR-497 and its putative target mucin1 (MUC1) in breast cancer. The present study explored how miR-497 regulates breast cancer progression in a MUC1-dependent manner.MethodsExpression of miR-497 and MUC1 was determined in breast cancer tissues and cells. Methylation specific polymerase chain reaction was used to measure the methylation status of CpG islands of miR-497 promoter, while chromatin immunoprecipitation assay was used to detect recruitment of methyltransferase to the promoter region of miR-497. Alteration in expression of miR-497 (overexpression) and MUC1 (up- and down-regulation) was performed to examine their roles in breast cancer biology in vitro and in vivo. The binding affinity between miR-497 and MUC1 was investigated through a bioinformatics database and dual luciferase reporter gene assay.ResultsMiR-497 was down-regulated and MUC1 was up-regulated in breast cancer tissues and cell lines. Besides, methylation induced a down-regulation of miR-497 in breast cancer. The bioinformatics analysis and dual luciferase reporter gene assay indicated that miR-497 targeted MUC1. Overexpression of miR-497 inhibited breast cancer cell proliferation and invasion and promoted the apoptosis of breast cancer cells by down-regulating MUC1. The inhibitory action of miR-497 on tumor growth was validated in vivo.ConclusionIn conclusion, miR-497 down-regulated MUC1 expression and subsequently suppressed breast cancer progression, highlighting miR-497 to be a potential biomarker and therapeutic target for breast cancer therapy.

PKM2-c-Myc-Survivin Cascade Regulates the Cell Proliferation, Migration, and Tamoxifen Resistance in Breast Cancer.

The M2 isoform of pyruvate kinase (PKM2), as a key glycolytic enzyme, plays important roles in tumorigenesis and chemotherapeutic drug resistance. However, the intricate mechanism of PKM2 as a protein kinase regulating breast cancer progression and tamoxifen resistance needs to be further clarified. Here, we reported that PKM2 controls the expression of survivin by phosphorylating c-Myc at Ser-62. Functionally, PKM2 knockdown suppressed breast cancer cell proliferation and migration, which could be rescued by overexpression of survivin. Interestingly, we found that the level of PKM2 expression was upregulated in the tamoxifen resistant breast cancer cells MCF-7/TAMR, and knockdown of PKM2 sensitized the cells to 4-hydroxytamoxifen (4OH-T). In addition, the elevated level of PKM2 correlates with poor relapse-free survival in breast cancer patients treated with tamoxifen. Overall, our findings demonstrated that PKM2–c-Myc–survivin cascade regulated the proliferation, migration and tamoxifen resistance of breast cancer cells, suggesting that PKM2 represents a novel prognostic marker and an attractive target for breast cancer therapeutics, and that PKM2 inhibitor combined with tamoxifen may be a promising strategy to reverse tamoxifen resistance in breast cancer patients.

Arctigenin Attenuates Breast Cancer Progression through Decreasing GM-CSF/TSLP/STAT3/β-Catenin Signaling.

Invasive breast cancer is highly regulated by tumor-derived cytokines in tumor microenvironment. The development of drugs that specifically target cytokines are promising in breast cancer treatment. In this study, we reported that arctigenin, a bioactive compound from Arctium lappa L., could decrease tumor-promoting cytokines GM-CSF, MMP-3, MMP-9 and TSLP in breast cancer cells. Arctigenin not only inhibited the proliferation, but also the invasion and stemness of breast cancer cells via decreasing GM-CSF and TSLP. Mechanistically, arctigenin decreased the promoter activities of GM-CSF and TSLP via reducing the nuclear translocation of NF-κB p65 which is crucial for the transcription of GM-CSF and TSLP. Furthermore, arctigenin-induced depletion of GM-CSF and TSLP inhibited STAT3 phosphorylation and β-catenin signaling resulting in decreased proliferation, invasion and stemness of breast cancer cells in vitro and in vivo. Our findings provide new insights into the mechanism by which tumor-promoting cytokines regulate breast cancer progression and suggest that arctigenin is a promising candidate for cytokine-targeted breast cancer therapy.

Long Noncoding RNA NEAT1 Promotes the Progression of Breast Cancer by Regulating miR-138-5p/ZFX Axis.

Background: Growing evidence demonstrated that long noncoding RNAs (lncRNAs) were involved in the progression of diverse cancers, including breast cancer (BC). Recent studies indicated that lncRNA nuclear enriched abundant transcript 1 (NEAT1) was overexpressed and facilitated tumor processes in many cancers. Nevertheless, the underlying mechanism of NEAT1 in regulating BC progression is still largely unknown. Materials and Methods: The abundance of NEAT1, microRNA-138-5p (miR-138-5p), and zinc finger protein X-linked (ZFX) was assessed by quantitative real-time polymerase chain reaction. Cell Counting Kit-8 (CCK-8) assay, flow cytometry, and transwell assay were utilized to evaluate cell proliferation, apoptosis, migration, and invasion, respectively. Western blot analysis was applied to detect the protein expression of CyclinD1, Bax, E-cadherin, and ZFX. The interaction between miR-138-5p and NEAT1 or ZFX was predicted by starBase v3.0 and validated by dual-luciferase reporter, RNA pull-down, and RNA immunoprecipitation assays. The mice xenograft model was established to investigate the roles of NEAT1 in vivo. Results: NEAT1 was highly expressed and miR-138-5p was lowly expressed in BC tissues and cells. NEAT1 interference or miR-138-5p restoration repressed cell proliferation, migration, and invasion but accelerated apoptosis in BC cells. Moreover, miR-138-5p directly interacted with NEAT1 and its knockdown reversed the suppressive impact of NEAT1 downregulation on the progression of BC cells. In addition, ZFX was a downstream target of miR-138-5p and its upregulation attenuated the antitumor role of miR-138-5p in BC cells. Besides, ZFX expression was positively regulated by NEAT1 and inversely modulated by miR-138-5p. Furthermore, interference of NEAT1 inhibited tumor growth by upregulating miR-138-5p and downregulating ZFX. Conclusion: NEAT1 affected BC progression through modulating miR-138-5p/ZFX axis, providing a vital theoretical basis for BC treatment.

Abstract 3976: Tumor-educated osteoblasts regulate breast cancer cell proliferation via extracellular vesicles

Abstract Breast cancer commonly traffics to bone, where breast cancer cells (BCCs) can survive undetected for years before metastatic outgrowth. This period of time can be defined as metastatic latency. In bone, BCCs interact with surrounding stromal cells, including osteoblasts (OBs), to shape the metastatic niche. Our lab discovered that there are at least two distinct subpopulations of OBs in the bone-tumor niche, based on protein marker expression. One group, “educated osteoblasts” (EOs) have engaged in crosstalk with BCCs whereas another group, naive OBs, have not. We have new, novel evidence that EOs regulate BCC proliferation, and may contribute to metastatic latency. The purpose of this study was to determine if extracellular vesicles (EVs) produced by EOs play a role in regulating BCC proliferation. We hypothesized that EVs produced by EOs, would decrease BCC proliferation. We first isolated EO-derived small EVs from cell culture media via ultracentrifugation and characterized the EVs for size, protein marker expression, and density floatation to validate the purity of the EV samples. We next sought to determine the functionality of EO-derived EVs with regards to regulating BCC proliferation. Strikingly, we found that EVs produced by EOs, but not naïve OBs, decreased BCC proliferation in a concentration dependent manner. We have observed this effect in both triple negative and ER-positive BCCs. Furthermore, using an EdU assay, we found that exposure to EO-derived EVs induces BCCs to undergo cell cycle arrest. Interestingly, we found that this cell cycle arrest was maintained as long as the BCCs were cultured in the presence of EO-derived EVs. However, the cell cycle arrest was reversible and BCC proliferation was restored upon removal of EO-derived EVs. We have also seen that exposure to EO-derived EVs leads to increases in BCC expression of the G1 checkpoint proteins, p21 and p27. We next wanted to investigate proliferative signaling pathways that may be deregulated in BCCs following exposure to EO-derived EVs. We found that EO-derived EVs reduce BCC levels of ERK1/2. This is consistent with previous literature indicating that low ERK1/2 levels are implicated in cell cycle arrest and even cancer cell quiescence. Because our data indicate EO-derived EVs induce sustained cell cycle arrest in BCCs, we desired to know if EO-derived EVs protected BCCs from chemotherapy-induced cell death. Excitingly, we have novel preliminary data demonstrating that BCCs exposed to EO-derived EVs and the chemotherapy drug, doxorubicin, have decreased cell death compared to BCCs exposed only to doxorubicin. Altogether, our data suggest that EOs play a crucial role in bone-tumor microenvironment, by regulating BCC proliferation, and may ultimately contribute to metastatic latency. This study underscores the importance of investigating EOs as regulators of breast cancer progression in bone. Supported by NIH R00 CA178177 and Commonwealth of Pennsylvania - Department of Health SAP 4100072566 for KMB. Citation Format: Alison B. Shupp, Karen M. Bussard. Tumor-educated osteoblasts regulate breast cancer cell proliferation via extracellular vesicles [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 3976.

Regulation of Breast Cancer Progression by Noncoding RNAs.

Breast cancer (BC) is the cardinal cause of cancer-related deaths among women across the globe. Our understanding of the molecular mechanisms underlying BC invasion and metastasis remains insufficient. Recent studies provide compelling evidence on the prospective contribution of noncoding RNAs (ncRNAs) and the association of different interactive mechanisms between these ncRNAs with breast carcinogenesis. MicroRNAs (small ncRNAs) and lncRNAs (long ncRNAs) have been explored extensively as classes of ncRNAs in the pathogenesis of several malignancies, including BC. In this review, we aim to provide a better understanding of the involvement of miRNAs and lncRNAs and their underlying mechanisms in BC development and progression that may assist the development of monitoring biomarkers and therapeutic strategies to effectively combat BC. These ncRNAs play critical roles in cell growth, cell cycle regulation, epithelialmesenchymal transition (EMT), invasion, migration, and apoptosis among others, and were observed to be highly dysregulated in several cancers. The miRNAs and lncRNAs were observed to interact with each other through several mechanisms that governed the expression of their respective targets and could act either as tumor suppressors or as oncogenes, playing a crucial part in breast carcinogenesis.

Notch-Inflammation Networks in Regulation of Breast Cancer Progression.

Members of the Notch family and chronic inflammation were each separately demonstrated to have prominent malignancy-supporting roles in breast cancer. Recent investigations indicate that bi-directional interactions that exist between these two pathways promote the malignancy phenotype of breast tumor cells and of their tumor microenvironment. In this review article, we demonstrate the importance of Notch-inflammation interplays in malignancy by describing three key networks that act in breast cancer and their impacts on functions that contribute to disease progression: (1) Cross-talks of the Notch pathway with myeloid cells that are important players in cancer-related inflammation, focusing mainly on macrophages; (2) Cross-talks of the Notch pathway with pro-inflammatory factors, exemplified mainly by Notch interactions with interleukin 6 and its downstream pathways (STAT3); (3) Cross-talks of the Notch pathway with typical inflammatory transcription factors, primarily NF-κB. These three networks enhance tumor-promoting functions in different breast tumor subtypes and act in reciprocal manners, whereby Notch family members activate inflammatory elements and vice versa. These characteristics illustrate the fundamental roles played by Notch-inflammation interactions in elevating breast cancer progression and propose that joint targeting of both pathways together may provide more effective and less toxic treatment approaches in this disease.

Abstract A073: TGF-beta receptor type-2 expression regulates breast cancer progression and is a prognostic marker for racial disparities

Abstract Transforming growth factor β (TGFβ) is one of the most important signaling pathways associated with cellular proliferation, and its dysregulation can lead to tumor development. TGFβ can act as either a tumor suppressor or a tumor promoter depending upon the cellular context and genetic alterations. TGFβ receptor type-2 (TGFβR2) is the ligand-binding receptor, and data shows that the aberration of TGFβR2 is associated with many different cancers including colon, gastric, biliary, pulmonary, and ovarian cancers. In this study, we focused on uncovering the functional role of TGFβR2 in regulating breast cancer (BrCa) progression. First, we analyzed the genomic alterations of TGFβR2 in a sample set from The Cancer Genome Atlas (TCGA, n=1084) on the cBioprotal platform. We focused on obtaining genetic modifications, including mutations and copy number alteration. Data indicated that almost 25% of the patient’s samples having TGFβ amplified copy number; however, only less than one percent patients have amplified copy of TGFβR2 and other TGFβ receptors, within across this sample set. Next, we have screened the level of TGFβR2 protein expression in different BrCa cell-lines. We found that the elevated level of TGFβR2 is associated with the most aggressive triple-negative MDA-MB-231 cells. It is also found that the TGFβR2 is secreted into extracellular space. Therefore, we next evaluated the expression level of TGFβR2 in patient’s serum samples. We have well defined and categorized BrCa patients serum samples (n=240) from the Clinical Breast Care Project led by Walter Reed National Military Medical Center, Bethesda. The differential expression level of TGFβR2 in serum indicated that the elevated level of TGFβR2 is associated with BrCa patients compared with healthy individuals. Furthermore, the serum level of TGFβR2 is higher in the African American patient population when compared to Caucasian patients, and most significant differences were found within Luminal B1 sub-type BrCa cases. To better understand the mechanism of the higher level of TGFβR2 protein expression, in association with aggressiveness, we hypothesized that increased levels of TGFβ ligand are inducing the expression of the receptor (TGFβR2) and eventually stimulating the oncogenic pathway. We have used a series of BrCa cell lines and incubated them with different concentrations of TGFβ ligand. The level of TGFβR2 protein was increased in BrCa cell lines after TGFβ ligand treatment. Increased levels of TGFβ2 ligand induces the expression of the relevant receptor. In summary, we quantified the expression levels of TGFβR2 in patients’ serum samples, which can be used to create a set of stage and race-specific candidate protein biomarkers for BrCa. We also found that the increased level of TGFβ ligand-induced the expression of the TGFβR2 receptor. We can also conclude that TGFβR2 is an important biomarker and possibly plays a role in racial disparities in breast cancer progression. Citation Format: Alakesh Bera, John Karaian, Harvey B Pollard, Hai Hu, Craig D Shriver, Meera Srivastava. TGF-beta receptor type-2 expression regulates breast cancer progression and is a prognostic marker for racial disparities [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr A073.

Silencing SCAMP1-TV2 Inhibited the Malignant Biological Behaviors of Breast Cancer Cells by Interaction With PUM2 to Facilitate INSM1 mRNA Degradation.

Background: Molecular-targeted therapy plays an important role in the combined treatment of breast cancer. Long noncoding RNA (LncRNA) plays a significant role in regulating breast cancer progression. The present study is to reveal the potential roles and molecular mechanism that the secretory carrier-associated membrane protein 1-transcript variant 2 (SCAMP1-TV2) has in breast.Methods: Cell Counting Kit-8 (CCK-8), RNA Immunoprecipitation (RIP), and RNA pull-down assays were employed to determine the interactions between SCAMP1-TV2 and Pumilio RNA binding family member 2 (PUM2). The luciferase reporter assays and chromatin immunoprecipitation (ChIP) assays were used to get to know the effect of human insulinoma-associated 1 (INSM1) directly on the SAM and SH3 domain containing 1 (SASH1) promoter.Results: Silenced SCAMP1-TV2 inhibited the proliferation, migration, and invasion of breast cancer cells, and promoted cell apoptosis. Meanwhile, SCAMP1-TV2 downregulation decreased its binding to PUM2 and increased the binding of PUM2 to INSM1 messenger RNA (mRNA), thus promoting the degradation of INSM1 mRNA. Silencing INSM1 decreased its inhibitory effect on SASH1 transcription and inhibited the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway. The xenograft tumor growth in a nude mice was significantly inhibited by the silencing of SCAMP1-TV2 in combination with the overexpression of PUM2.Conclusions: SCAMP1-TV2/PUM2/INSM1 pathway plays an important role in regulating the biological behavior of breast cancer cells.

Autophagy-associated circRNA circCDYL augments autophagy and promotes breast cancer progression

BackgroundAlthough both circular RNAs (circRNAs) and autophagy are associated with the function of breast cancer (BC), whether circRNAs regulate BC progression via autophagy remains unknown. In this study, we aim to explore the regulatory mechanisms and the clinical significance of autophagy-associated circRNAs in BC.MethodsAutophagy associated circRNAs were screened by circRNAs deep sequencing and validated by qRT-PCR in BC tissues with high- and low- autophagic level. The biological function of autophagy associated circRNAs were assessed by plate colony formation, cell viability, transwells, flow cytometry and orthotopic animal models. For mechanistic study, RNA immunoprecipitation, circRNAs pull-down, Dual luciferase report assay, Western Blot, Immunofluorescence and Immunohistochemical staining were performed.ResultsAn autophagy associated circRNA circCDYL was elevated by 3.2 folds in BC tissues as compared with the adjacent non-cancerous tissues, and circCDYL promoted autophagic level in BC cells via the miR-1275-ATG7/ULK1 axis; Moreover, circCDYL enhanced the malignant progression of BC cells in vitro and in vivo. Clinically, increased circCDYL in the tumor tissues and serum of BC patients was associated with higher tumor burden, shorter survival and poorer clinical response to therapy.ConclusionscircCDYL promotes BC progression via the miR-1275-ATG7/ULK1-autophagic axis and circCDYL could act as a potential prognostic and predictive molecule for breast cancer patients.

Circular RNA circRNF20 promotes breast cancer tumorigenesis and Warburg effect through miR-487a/HIF-1\u03b1/HK2

Compelling evidence has demonstrated the potential functions of circular RNAs (circRNAs) in breast cancer (BC) tumorigenesis. Nevertheless, the underlying mechanism by which circRNAs regulate BC progression is still unclear. The purpose of present research was to investigate the novel circRNA circRNF20 (hsa_circ_0087784) and its role in BC. CircRNA microarray sequencing revealed that circRNF20 was one of the upregulated transcripts in BC samples. Increased circRNF20 level predicted the poor clinical outcome in BC specimens. Functionally, circRNF20 promoted the proliferation and Warburg effect (aerobic glycolysis) of BC cells. Mechanistically, circRNF20 harbor miR-487a, acting as miRNA sponge, and then miR-487a targeted the 3’-UTR of hypoxia-inducible factor-1α (HIF-1α). Moreover, HIF-1α could bind with the promoter of hexokinase II (HK2) and promoted its transcription. In conclusion, this finding illustrates the vital roles of circRNF20 via the circRNF20/ miR-487a/HIF-1α/HK2 axis in breast cancer progress and Warburg effect, providing an interesting insight for the BC tumorigenesis.

Anti-Angiogenic Effects of Phytochemicals on miRNA Regulating Breast Cancer Progression.

Several phytochemicals have been identified for their role in modifying miRNA regulating tumor progression. miRNAs modulate the expression of several oncogenes and tumor suppressor genes including the genes that regulate tumor angiogenesis. Hypoxia inducible factor-1 alpha (HIF-1α) signaling is a central axis that activates oncogenic signaling and acts as a metabolic switch in endothelial cell (EC) driven tumor angiogenesis. Tumor angiogenesis driven by metabolic reprogramming of EC is crucial for tumor progression and metastasis in many different cancers, including breast cancers, and has been linked to aberrant miRNA expression profiles. In the current article, we identify different miRNAs that regulate tumor angiogenesis in the context of oncogenic signaling and metabolic reprogramming in ECs and review how selected phytochemicals could modulate miRNA levels to induce an anti-angiogenic action in breast cancer. Studies involving genistein, epigallocatechin gallate (EGCG) and resveratrol demonstrate the regulation of miRNA-21, miRNA-221/222 and miRNA-27, which are prognostic markers in triple negative breast cancers (TNBCs). Modulating the metabolic pathway is a novel strategy for controlling tumor angiogenesis and tumor growth. Cardamonin, curcumin and resveratrol exhibit their anti-angiogenic property by targeting the miRNAs that regulate EC metabolism. Here we suggest that using phytochemicals to target miRNAs, which in turn suppresses tumor angiogenesis, should have the potential to inhibit tumor growth, progression, invasion and metastasis and may be developed into an effective therapeutic strategy for the treatment of many different cancers where tumor angiogenesis plays a significant role in tumor growth and progression.

Pan-cancer analysis of RNA methyltransferases identifies FTSJ3 as a potential regulator of breast cancer progression

ABSTRACTRNA methylation, catalysed by a set of RNA methyltransferases (RNMTs), modulates RNA structures, properties, and biological functions. RNMTs are increasingly documented to be dysregulated in various human diseases, particularly developmental disorders and cancer. However, the genomic and transcriptomic alterations of RNMTs, as well as their functional roles in human cancer, are limited. In this study, we utilized an unbiased approach to examine copy number alterations and mutation rates of 58 RNMTs in more than 10,000 clinical samples across 32 human cancer types. We also investigated these alterations and RNMT expression level as they related to clinical features such as tumour subtype, grade, and survival in a large cohort of tumour samples, focusing on breast cancer. Loss-of-function analysis was performed to examine RNMT candidates with important roles in growth and viability of breast cancer cells. We identified a subset of RNMTs, notably TRMT12, NSUN2, TARBP1, and FTSJ3, that were amplified or mutated in a subset of human cancers. Several RNMTs were significantly associated with breast cancer aggressiveness and poor prognosis. Loss-of-function analysis indicated FTSJ3, a 2ʹ-O-Me methyltransferase, as a candidate RNMT with functional roles in promoting cancer growth and survival. A subset of RNMTs, like FTSJ3, represents promising novel targets for anticancer drug discovery. Our findings provide a framework for further study of the functional consequences of RNMT alterations in human cancer and for developing therapies that target cancer-promoting RNMTs in the future.

Gene signatures and prognostic analyses of the Tob/BTG pituitary tumor-transforming gene (PTTG) family in clinical breast cancer patients.

Breast cancer is the most common cancer type in females, and exploring the mechanisms of disease progression is playing a crucial role in the development of potential therapeutics. Pituitary tumor-transforming gene (PTTG) family members are well documented to be involved in cell-cycle regulation and mitosis, and contribute to cancer development by their involvement in cellular transformation in several tumor types. The critical roles of PTTG family members as crucial transcription factors in diverse types of cancers are recognized, but how they regulate breast cancer development still remains mostly unknown. Meanwhile, a holistic genetic analysis exploring whether PTTG family members regulate breast cancer progression via the cell cycle as well as the energy metabolism-related network is lacking. To comprehensively understand the messenger RNA expression profiles of PTTG proteins in breast cancer, we herein conducted a high-throughput screening approach by integrating information from various databases such as Oncomine, Kaplan-Meier Plotter, Metacore, ClueGo, and CluePedia. These useful databases and tools provide expression profiles and functional analyses. The present findings revealed that PTTG1 and PTTG3 are two important genes with high expressions in breast cancer relative to normal breast cells, implying their unique roles in breast cancer progression. Results of our coexpression analysis demonstrated that PTTG family genes were positively correlated with thiamine triphosphate (TTP), deoxycytidine triphosphate (dCTP) metabolic, glycolysis, gluconeogenesis, and cell-cycle related pathways. Meanwhile, through Cytoscape analyzed indicated that in addition to the metastasis markers AURKA, AURKB, and NDC80, many of the kinesin superfamily (KIF) members including KIFC1, KIF2C, KIF4A, KIF14, KIF20A, KIF23, were also correlated with PTTG family transcript expression. Finally, we revealed that high levels of PTTG1 and PTTG3 transcription predicted poor survival, which provided useful insights into prospective research of cancer associated with the PTTG family. Therefore, these members of the PTTG family would serve as distinct and essential prognostic biomarkers in breast cancer.

Melatonin Regulates Breast Cancer Progression by the lnc010561/miR-30/FKBP3 Axis

Melatonin has been recognized to slow breast cancer growth. The molecular mechanisms may involve long non-coding RNAs (lncRNAs). However, little is known on how melatonin affects lncRNA expression and function in breast cancer. We used microarrays to explore the expression profile of mRNAs and lncRNAs in melatonin-treated breast cancer cells. Kyoto encyclopedia of genes and genomes (KEGG) and Reactome pathways analysis were performed to identify the signaling pathways affected by altered expressed mRNAs after melatonin treatment. To explore the functions and mechanisms of the selected differentially expressed mRNA and lncRNA in breast cancer, we performed a series of experiments. We found that FK506-binding protein 3 (FKBP3) and lnc010561 were downregulated in melatonin-treated breast cancer cells. Knockdown of FKBP3 and lnc010561 inhibited breast cancer proliferation and invasion, and induced apoptosis. Also, lnc010561 and FKBP3 functioned as competing endogenous RNAs (ceRNAs) for miR-30. Our findings suggested that melatonin regulated breast cancer progression by the lnc010561/miR-30/FKBP3 axis. Melatonin may, therefore, function as an anticancer strategy for breast cancer.

ERK1 indicates good prognosis and inhibits breast cancer progression by suppressing YAP1 signaling.

The mitogen-activated protein kinase/extracellular signal-regulated (MAPK/ERK) pathway is a well-characterized signaling pathway during the development of various cancer types. ERK1 and ERK2, the two kinase effectors of MAPK cascade, exhibit high similarity. However, it is still unknown whether these two kinases are functionally different or in contrast functionally redundant during the development of breast cancer. We found that ERK1 expression levels were significantly lower in basal breast cancer compared with luminal breast cancer and normal breast tissues. RNA sequencing data suggested that ERK1 was associated with Hippo signaling pathway and cell proliferation in breast cancer cells. The gene set enrichment analysis (GSEA) further showed enrichment for YAP1 signaling pathway in breast cancer cell lines and tumors with low expression of ERK1. Silencing of ERK1 elevated YAP1 expression and TEAD activity in breast cancer cells. Additionally, ERK1 inhibited breast cancer cell proliferation via regulation of YAP1. The Kaplan-Meier analysis of data in patients with breast cancer suggested that, higher expression of ERK1 was associated with better prognosis, whereas, higher expression of ERK2 predicted poorer prognosis. These findings unveiled the role of ERK1 on regulation of YAP1 signaling pathway, indicating ERK1 as a negative regulator of breast cancer progression.

MicroRNA-296 functions as a tumor suppressor in breast cancer by targeting FGFR1 and regulating the Wnt/β-catenin signaling pathway.

Breast cancer (BC) is a common malignancy all over the world. However, the detailed mechanism underlying BC progression remains incompletely understood. MicroRNAs (miRNAs) have been observed to play crucial roles in tumorigenesis. The present study aimed to determine the expression and function of miR-296 in BC. MiR-296 expressions in BC tissue samples and cell lines were examined by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). After that, we performed functional assays, including MTT (3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assays and transwell assays, to show the functions of miR-296 in BC cell proliferation, invasion and migration. Immunological histological chemistry (IHC) assays were carried out to detect the expression levels of fibroblast growth factor receptor 1 (FGFR1) in BC tissue samples. Western blot was used to explore potential mechanisms of miR-296 in regulating BC progression. A Luciferase reporter assay was carried out to confirm the target gene of miR-296. Quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) results demonstrated a significant decrease of miR-296 expressions in BC when compared to the corresponding normal controls. In addition, the decreased miR-296 was correlated with the malignant phenotypes and poorer prognosis of BC patients. The functional assays indicated that miR-296 restoration could repress the proliferation, invasion and migration abilities of BC cells. Moreover, the results of the current study revealed that miR-296 exerted the repressive functions in BC cells via regulating FGFR1, the Wnt/β-catenin signaling pathway and EMT. Additionally, miR-296 up-regulation could inhibit in vivo BC cell growth. All these findings indicated that miR-296 exerted anti-BC functions, providing novel therapeutic strategies in BC treatment.