miR-376a inhibits breast cancer cell progression by targeting neuropilin-1 NR

NORAD-Regulated Signaling Pathways in Breast Cancer Progression

Long non-coding RNA activated by DNA damage (NORAD) has recently been associated with pathologic mechanisms underlying cancer progression. Due to NORAD's extended range of interacting partners, there has been contradictory data on its oncogenic or tumor suppressor roles in BC. This review will summarize the function of NORAD in different BC subtypes and how NORAD impacts crucial signaling pathways in this pathology. Through the preferential binding to pumilio (PUM) proteins PUM1 and PUM2, NORAD has been shown to be involved in the control of cell cycle, angiogenesis, mitosis, DNA replication and transcription and protein translation. More recently, NORAD has been associated with PUM-independent roles, accomplished by interacting with other ncRNAs, mRNAs and proteins. The intricate network of NORAD-mediated signaling pathways may provide insights into the potential design of novel unexplored strategies to overcome chemotherapy resistance in BC treatment.

Non-coding regions of nuclear-DNA-encoded mitochondrial genes and intergenic sequences are targeted by autoantibodies in breast cancer

Autoantibodies against mitochondrial-derived antigens play a key role in chronic tissue inflammation in autoimmune disorders and cancers. Here, we identify autoreactive nuclear genomic DNA (nDNA)-encoded mitochondrial gene products (GAPDH, PKM2, GSTP1, SPATA5, MFF, TSPOAP1, PHB2, COA4, and HAGH) recognized by breast cancer (BC) patients’ sera as nonself, supporting a direct relationship of mitochondrial autoimmunity to breast carcinogenesis. Autoreactivity of multiple nDNA-encoded mitochondrial gene products was mapped to protein-coding regions, 3’ untranslated regions (UTRs), as well as introns. In addition, autoantibodies in BC sera targeted intergenic sequences that may be parts of long non-coding RNA (lncRNA) genes, including LINC02381 and other putative lncRNA neighbors of the protein-coding genes ERCC4, CXCL13, SOX3, PCDH1, EDDM3B, and GRB2. Increasing evidence indicates that lncRNAs play a key role in carcinogenesis. Consistent with this, our findings suggest that lncRNAs, as well as mRNAs of nDNA-encoded mitochondrial genes, mechanistically contribute to BC progression. This work supports a new paradigm of breast carcinogenesis based on a globally dysfunctional genome with altered function of multiple mitochondrial and non-mitochondrial oncogenic pathways caused by the effects of autoreactivity-induced dysregulation of multiple genes and their products. This autoimmunity-based model of carcinogenesis will open novel avenues for BC treatment.

A tumor microenvironment-related risk model for predicting the prognosis and tumor immunity of breast cancer patients

Background

This study aimed to construct a tumor microenvironment (TME)-related risk model to predict the overall survival (OS) of patients with breast cancer.

Methods

Gene expression data from The Cancer Genome Atlas was used as the training set. Differentially expressed gene analysis, prognosis analysis, weighted gene co-expression network analysis, Least Absolute Shrinkage and Selection Operator regression analysis, and Wald stepwise Cox regression were performed to screen for the TME-related risk model. Three Gene Expression Omnibus databases were used to validate the predictive efficiency of the prognostic model. The TME-risk-related biological function was investigated using the gene set enrichment analysis (GSEA) method. Tumor immune and mutation signatures were analyzed between low- and high-TME-risk groups. The patients’ response to chemotherapy and immunotherapy were evaluated by the tumor immune dysfunction and exclusion (TIDE) score and immunophenscore (IPS).

Results

Five TME-related genes were screened for constructing a prognostic signature. Higher TME risk scores were significantly associated with worse clinical outcomes in the training set and the validation set. Correlation and stratification analyses also confirmed the predictive efficiency of the TME risk model in different subtypes and stages of breast cancer. Furthermore, immune checkpoint expression and immune cell infiltration were found to be upregulated in the low-TME-risk group. Biological processes related to immune response functions were proved to be enriched in the low-TME-risk group through GSEA analysis. Tumor mutation analysis and TIDE and IPS analyses showed that the high-TME-risk group had more tumor mutation burden and responded better to immunotherapy.

Conclusion

The novel and robust TME-related risk model had a strong implication for breast cancer patients in OS, immune response, and therapeutic efficiency.

Neuropilin (NRPs) Related Pathological Conditions and Their Modulators

Neuropilin 1 (NRP1) represents one of the two homologous neuropilins (NRP, splice variants of neuropilin 2 are the other) found in all vertebrates. It forms a transmembrane glycoprotein distributed in many human body tissues as a (co)receptor for a variety of different ligands. In addition to its physiological role, it is also associated with various pathological conditions. Recently, NRP1 has been discovered as a coreceptor for the SARS-CoV-2 viral entry, along with ACE2, and has thus become one of the COVID-19 research foci. However, in addition to COVID-19, the current review also summarises its other pathological roles and its involvement in clinical diseases like cancer and neuropathic pain. We also discuss the diversity of native NRP ligands and perform a joint analysis. Last but not least, we review the therapeutic roles of NRP1 and introduce a series of NRP1 modulators, which are typical peptidomimetics or other small molecule antagonists, to provide the medicinal chemistry community with a state-of-the-art overview of neuropilin modulator design and NRP1 druggability assessment.

Insights from the Menstrual Cycle in Pulmonary Arterial Hypertension

Rationale: Sex hormones play a role in pulmonary arterial hypertension (PAH), but the menstrual cycle has never been studied.Objectives: We conducted a prospective observational study of eight women with stable PAH and 20 healthy controls over one cycle.Methods: Participants completed four study visits 1 week apart starting on the first day of menstruation. Relationships between sex hormones, hormone metabolites, and extracellular vesicle microRNA (miRNA) expression and clinical markers were compared with generalized linear mixed modeling.Results: Women with PAH had higher but less variable estradiol (E2) levels (P < 0.001) that tracked with 6-minute walk distance (P < 0.001), N-terminal prohormone of brain natriuretic peptide (P = 0.03) levels, and tricuspid annular plane systolic excursion (P < 0.01); the direction of these associations depended on menstrual phase. Dehydroepiandrosterone sulfate (DHEA-S) levels were lower in women with PAH (all visits, P < 0.001). In PAH, each 100-μg/dl increase in DHEA-S was associated with a 127-m increase in 6-minute walk distance (P < 0.001) and was moderated by the cardioprotective E2 metabolite 2-methoxyestrone (P < 0.001). As DHEA-S increased, N-terminal prohormone of brain natriuretic peptide levels decreased (P = 0.001). Expression of extracellular vesicle miRNAs-21, -29c, and -376a was higher in PAH, moderated by E2 and DHEA-S levels, and tracked with hormone-associated changes in clinical measures.Conclusions: Women with PAH have fluctuations in cardiopulmonary function during menstruation driven by E2 and DHEA-S. These hormones in turn influence transcription of extracellular vesicle miRNAs implicated in the pathobiology of pulmonary vascular disease and cancer.

Emerging Evidence of the Functional Impact of the miR379/miR656 Cluster (C14MC) in Breast Cancer

Many microRNAs exist in clusters that share comparable sequence homology and may target genes in a common pathway. The miR-379/miR-656 (C14MC) cluster is imprinted in the DLK1-Dio3 region of 14q32.3 and contains 42 miRNAs. It plays a functional role in numerous biological pathways including vascular remodeling and early development. With many C14MC miRNAs highlighted as potential tumor suppressors in a variety of cancers, the role of this cluster in breast cancer (BC) has garnered increased attention in recent years. This review focuses on C14MC in BC, providing an overview of the constituent miRNAs and addressing each in terms of functional impact, potential target genes/pathways, and, where relevant, biomarker capacity. Studies have revealed the regulation of key factors in disease progression and metastasis including tyrosine kinase pathways and factors critical to epithelial–mesenchymal transition (EMT). This has potentially important clinical implications, with EMT playing a critical role in BC metastasis and tyrosine kinase inhibitors (TKIs) in widespread use for the treatment of BC. While the majority of studies have reported tumor-suppressing roles for these miRNAs, some have highlighted their potential as oncomiRs. Understanding the collective contribution of miRNAs within C14MC to BC may support improved understanding of disease etiology and present novel approaches to targeted therapy.

circPGAM1 enhances autophagy signaling during laryngocarcinoma drug resistance by regulating miR-376a

circRNAs have been shown to be involved in cancer progression. It is unclear whether circPGAM1 exerts its effect on laryngocarcinoma drug resistance. In this study, we employed colony formation and MTT assay to determine colony number and cell viability under cisplatin treatment. TUNEL experiment was used to evaluate apoptosis of laryngocarcinoma cells in the presence of cisplatin. Xenograft tumor experiment was performed to assess in vivo tumor growth of SNU46 cells. We found that circPGAM1 enhanced colony formation and viability of SNU46 and M4E cells. In contrast, circPGAM1 caused attenuated cell apoptosis. Furthermore, we also confirmed that circPGAM1 played a key role in tumor growth in animal model and clinical patients. miR-376a was identified and proved to act as key effector for circPGAM1-mediated drug resistance. Finally, autophagy-related gene ATG2A was shown to rescue miR-376a-modulated drug resistance of laryngocarcinoma cells. Herein, we illuminate the role of circPGAM1 in laryngocarcinoma drug resistance, thereby facilitating development of targeted therapy for treating laryngocarcinoma.

miR-376c-3p modulates the properties of breast cancer stem cells by targeting RAB2A

MicroRNAs (miRNAs/miRs) negatively regulate gene expression and participate in various cellular processes. miRNA dysregulation is associated with cancer progression. The present study aimed to identify the miRNAs that participate in breast cancer tumorigenesis and determine the mechanism that underlies this. miRNA microarray data analysis and validation assays indicated that miR-376c-3p was downregulated in breast tumour tissues and breast cancer stem cells (BCSCs) compared with adjacent non-cancerous tissues and MCF-10A cells, respectively. Ras-related protein Rab-2A (RAB2A) was predicted as a target of miR-376c-3p, which was confirmed by conducting further experiments. miR-376c-3p regulated the BCSC population and the expression of stem cell regulatory genes by targeting RAB2A. By performing mammosphere, Cell Counting Kit-8, colony formation and transwell invasion assays, it was demonstrated that miR-376c-3p also inhibited BCSC self-renewal, proliferation and invasion by regulating RAB2A expression. Using a xenograft mouse model, it was revealed that miR-376c-3p overexpression suppressed breast cancer growth in vivo. In conclusion, the results indicated that miR-376c-3p targeted RAB2A to regulate BCSC fate and properties; therefore, miR-376c-3p may serve as a potential therapeutic target for breast cancer.

LncRNA TTN‑AS1 promotes endometrial cancer by sponging miR‑376a‑3p

Increasing research has demonstrated that lncRNAs participate in the development of multiple cancer types. However, the role of TTN-AS1 in endometrial cancer (EC) remains unknown. The present study aimed to explore the function of titin-antisense RNA1 (TTN-AS1) in EC progression and the underlying mechanisms. qRT-PCR was performed to assess the TTN-AS1 expression patterns in EC tissues and cell lines. Loss of function experiments were carried out to estimate the effects of TTN-AS1 on EC cell proliferation, migration and invasion. To reveal the underlying mechanisms, informatics tools were used to predict the targets. Rescue experiments were performed to investigate the TTN-AS1-regulated miR-376a-3p/pumilio homolog 2 (PUM2) axis involved. The results of the present study revealed that TTN-AS1 was highly expressed in both EC tissues and cell lines, and TTN-AS1 knockdown inhibited EC cell proliferation, migration and invasion. With respect to the mechanisms, miR-376a-3p was revealed to be targeted by TTN-AS1, and reversed the effects on EC development induced by TTN-AS1. In addition, PUM2 was positively regulated by TTN-AS1, and miR-376a-3p mediated the regulation between them. Furtherly, in vivo experiments confirmed the results. Collectively, TTN-AS1 enhanced EC cell proliferation and metastasis by targeting the miR-376a-3p/PUM2 axis, which may shed light on EC diagnosis and treatment.

LncRNA SNHG1 alleviated apoptosis and inflammation during ischemic stroke by targeting miR-376a and modulating CBS/H2S pathway

BACKGROUND

Ischemic stroke (IS) is a major public health issue causing mortality and disability and is more difficult to treat than other cerebral diseases. Previous study reported that miR-376a was upregulated in the serum of stroke patients, indicating that miR-376a played potential role in occurrence and development of stroke.

METHODS

IS cell model was induced by oxygen-glucose deprivation (OGD) exposed HCMEC/D3 cells. The mRNA level of SNHG1, miR-376a and inflammatory cytokines were detected by q-PCR. Protein level of CBS, apoptotic proteins were examined by Western blot. Apoptosis was analyzed by flow cytometry, and H₂S level was measured by kit. Interaction among lncRNA, miRNA and target gene was validated by luciferase assay.

RESULTS

Our research revealed that mRNA level of SNHG1 and CBS in HCMEC/D3 cells was downregulated while miR-376a was upregulated under OGD conditions. Further results demonstrated that miR-376a overexpression promoted apoptosis and inflammation while SNHG1 overexpressing alleviated such processes. Mechanistically, SNHG1 directly targeted miR-376a, and CBS was a target of miR-376a. Moreover, SNHG1 exert its function via inhibiting miR-376a to regulate CBS expression.

CONCLUSION

LncRNA SNHG1 depressed apoptosis and inflammation of IS cell model via inhibiting miR-376a and upregulating CBS/H₂S signal. These results show light on underlying mechanisms of IS and provide potential targets for IS therapy.

Neuropilin: Handyman and Power Broker in the Tumor Microenvironment

Neuropilin-1 and neuropilin-2 form a small family of transmembrane receptors, which, due to the lack of a cytosolic protein kinase domain, act primarily as co-receptors for various ligands. Performing at the molecular level both the executive and organizing functions of a handyman as well as of a power broker, they are instrumental in controlling the signaling of various receptor tyrosine kinases, integrins, and other molecules involved in the regulation of physiological and pathological angiogenic processes. In this setting, the various neuropilin ligands and interaction partners on various cells of the tumor microenvironment, such as cancer cells, endothelial cells, cancer-associated fibroblasts, and immune cells, are surveyed. The suitability of various neuropilin-targeting substances and the intervention in neuropilin-mediated interactions is considered as a possible building block of tumor therapy.

Tumor Suppressor Function of miR-127-3p and miR-376a-3p in Osteosarcoma Cells

Since the introduction of high-dose chemotherapy about 35 years ago, survival rates of osteosarcoma patients have not been significantly improved. New therapeutic strategies replacing or complementing conventional chemotherapy are therefore urgently required. MicroRNAs represent promising targets for such new therapies, as they are involved in the pathology of multiple types of cancer, and aberrant expression of several miRNAs has already been shown in osteosarcoma. In this study, we identified silencing of miR-127-3p and miR-376a-3p in osteosarcoma cell lines and tissues and investigated their role as potential tumor suppressors in vitro and in vivo. Transfection of osteosarcoma cells (n = 6) with miR-127-3p and miR-376a-3p mimics significantly inhibited proliferation and reduced the colony formation capacity of these cells. In contrast, we could not detect any influence of miRNA restoration on cell cycle and apoptosis induction. The effects of candidate miRNA restoration on tumor engraftment and growth in vivo were analyzed using a chicken chorioallantoic membrane (CAM) assay. Cells transfected with mir-127-3p and miR-376a-3p showed reduced tumor take rates and tumor volumes and a significant decrease of the cumulative tumor volumes to 41% and 54% compared to wildtype cells. The observed tumor suppressor function of both analyzed miRNAs indicates these miRNAs as potentially valuable targets for the development of new therapeutic strategies for the treatment of osteosarcoma.

miRNA expression changes during the course of neoadjuvant bevacizumab and chemotherapy treatment in breast cancer

One of the hallmarks of cancer is sustained angiogenesis. Favorable results have been reported in some breast cancer (BC) patients receiving antiangiogenic therapy with bevacizumab (Bev) in combination with chemotherapy, and further knowledge on how Bev can be optimally combined with conventional treatment to increase efficacy is strongly needed. In this randomized, neoadjuvant phase II clinical trial, 132 patients with HER2-negative, nonmetastatic BC were treated with Bev in combination with sequential chemotherapy. Biopsies were sampled before treatment, after 12 weeks with anthracycline and after taxane therapy at week 25. MicroRNA (miRNA) expression profiling was performed on biopsies from each time point. Altogether, 241 biopsies were analyzed with the aim of identifying miRNA-based biomarkers of response to therapy. Results from the miRNA analyses were reported for the ER-positive cohort, which were previously demonstrated to benefit from antiangiogenic therapy in this study. For both treatment arms of this cohort, significantly different expression was observed for 217 miRNAs between objective responding and nonresponding patients before treatment initiation. These miRNAs have been linked to regulation of epithelial-mesenchymal transition, metastasis, and tumor growth, among other processes. Bev in combination with chemotherapy resulted in similar miRNA changes to chemotherapy alone. However, the deregulation of miRNA expression occurred earlier in the Bev arm. In both arms, tumor suppressor miRNAs were found upregulated after treatment, while oncogenic miRNAs were downregulated in the Bev arm. Patients responding to Bev showed a strong correlation between deregulated miRNAs and decreased proliferation score during the course of treatment, with downregulation of miR-4465 as the strongest indicator of reduced proliferation. Integrative analyses at miRNA-, gene-, and protein expression further indicated a longitudinal decrease in proliferation. Altogether, the results indicate that proliferation might represent a predictive factor for increased Bev sensitivity, which may aid in the identification of patients who could potentially benefit from Bev.

Long noncoding RNA TTN-AS1 enhances the malignant characteristics of osteosarcoma by acting as a competing endogenous RNA on microRNA-376a thereby upregulating dickkopf-1

The expression levels and detailed functions of TTN-AS1 in osteosarcoma (OS) have not yet been explored. This study aimed to measure TTN-AS1 expression in OS tissues and cell lines, investigate its specific roles in the aggressive characteristics of OS cells in vitro and in vivo, and elucidate the regulatory mechanisms of TTN-AS1 action. TTN-AS1 expression was high in OS tissue samples and cell lines; TTN-AS1 overexpression correlated with the clinical stage, distant metastasis, and shorter overall survival of the patients. A TTN-AS1 knockdown inhibited OS cell proliferation, migration, and invasion and induced apoptosis in vitro and slowed tumor growth in vivo. Mechanism investigation revealed that TTN-AS1 acts as a competing endogenous RNA on microRNA-376a-3p (miR-376a) in OS cells. Dickkopf-1 (DKK1) mRNA was identified as a direct target of miR-376a in OS cells. Resumption of DKK1 expression reversed the tumor-suppressive activities of miR-376a overexpression in OS cells. The knockdown of miR-376a counteracted the reduction in the malignant characteristics of OS cells by the downregulation of TTN-AS1. In conclusion, TTN-AS1 functions as a competing endogenous RNA targeting miR-376a and increases the malignancy of OS cells in vitro and in vivo by upregulating DKK1.

Identification of novel mRNA-miRNA-lncRNA competing endogenous RNA network associated with prognosis of breast cancer

Aim: To identify novel competing endogenous RNA (ceRNA) network related to patients prognosis in breast cancer. Materials & methods: Dysregulated mRNA based on intersection of three Gene Expression Omnibus and The Cancer Genome Atlas datasets were analyzed by bioinformatics. Results: In total 72 upregulated and 208 downregulated genes were identified. Functional analysis showed that some pathways related to cancer were significantly enriched. By means of stepwise reverse prediction and validation from mRNA to lncRNA, 19 hub genes, nine key miRNA and four key lncRNAs were identified by expression and survival analysis. Ultimately, the coexpression analysis identified RRM2-let-7a-5p-SNHG16/MAL2 as key ceRNA subnetwork associated with prognosis of breast cancer. Conclusion: We successfully constructed a novel ceRNA network, among which each component was significantly associated with breast cancer prognosis.

The downregulation of miR-519a predicts poor prognosis and contributes to tumor progression in gastric cancer

INTRODUCTION

MicroRNAs (miRNAs) have been demonstrated to be involved in the pathogenesis of various human cancers. However, the role of microRNA-519a (miR-519a) in gastric cancer (GC) remains unclear. This study aimed to investigate the clinical value and biological function of miR-519a in GC.

METHODS

The expression of miR-519a in GC tissues and cell lines was estimated by quantitative real-time polymerase chain reaction (qRT-PCR). A survival analysis for GC patients was performed using the Kaplan-Meier method. A Cox regression analysis was used to confirm the prognostic value of miR-519a. The biological function and potential targets of miR-519a in GC progression were assessed using cell experiments.

RESULTS

In this study, we found that miR-519a was an important tumor suppressor with downregulated expression in GC tissues and cells compared with the normal controls (all P < 0.05). MiR-519a expression was inversely correlated with differentiation, lymph node metastasis, and patients' TNM stages. Decreased miR-519a expression was associated with the poor overall survival of GC patients (log-rank P = 0.002) and served as an independent prognostic biomarker for the patients. The in vitro analyses indicated that miR-519a overexpression in GC cells resulted in inhibited cell proliferation, migration and invasion, and IGFBP1 was determined to be a direct target of miR-519a.

CONCLUSION

All the data in the present study revealed that the downregulated expression of miR-519a predicts the poor prognosis of GC and is involved in the regulation of GC progression. We consider that miR-519a may be a candidate therapeutic target for GC treatment.

miR-376a inhibits the proliferation and invasion of osteosarcoma by targeting FBXO11

Dysregulation of microRNAs (miRNAs) is frequently found in the tumorigenesis of osteosarcoma (OS). miR-376a was found to play tumor suppressive roles in human cancers. However, the role of miR-376a in OS remains unclear. The expression of miR-376a was analyzed by quantitative real-time PCR (qRT-PCR) in OS cell lines. Cell proliferation assay, cell invasion assay, and cell apoptosis assay were performed to detect the biological function of miR-376a after synthetic miRNA transfection. The target of miR-376a was predicted by TargetScan and miRDB, and further validated by luciferase activity reporter assay and western blot. miR-376a expression was revealed to be decreased in OS cell lines. In vitro experiments showed that overexpression of miR-376a inhibits OS cell proliferation and invasion but promotes apoptosis. Luciferase activity reporter assay and western blot assay showed F-box protein 11 (FBXO11) was a direct target of miR-376a. Furthermore, FBXO11 mediated the role of miR-376a on the proliferation, invasion, and apoptosis of OS cells. Collectively, these results revealed miR-376a functions as a tumor suppressor by targeting FBXO11 in OS. It may be developed as a therapeutic target for OS patients.

Gene Expression and miRNAs Profiling: Function and Regulation in Human Epidermal Growth Factor Receptor 2 (HER2)-Positive Breast Cancer

Breast cancer is the second most common cause of cancer-related deaths among women worldwide. It is a heterogeneous disease with four major molecular subtypes. One of the subtypes, human epidermal growth factor receptor 2 (HER2)-enriched (HER2-positive) is characterized by the absence of estrogen and progesterone receptors and overexpression of HER2 receptor, and accounts for 15–20% of all breast cancers. Despite the anti-HER2 and cytotoxic chemotherapy, HER2 subtype is an aggressive disease with significant mortality. Recent advances in molecular biology techniques, including gene expression profiling, proteomics, and microRNA analysis, have been extensively used to explore the underlying mechanisms behind human breast carcinogenesis and metastasis including HER2-positive breast cancer, paving the way for developing new targeted therapies. This review focuses on recent advances on gene expression and miRNA status in HER2-positive breast cancer.

Neoadjuvant Chemotherapy Alters Neuropilin-1, PlGF, and SNAI1 Expression Levels and Predicts Breast Cancer Patients Response

Circulating proteins hold a potential benefit as biomarkers for precision medicine. Previously, we showed that systemic levels of neuropilin-1 (NRP-1) and its associated molecules correlated with poor-prognosis breast cancer. To further identify the role of NRP-1 and its interacting molecules in correspondence with patients' response to neoadjuvant chemotherapy (NAC), we conducted a comparative study on blood and tissue samples collected from a cohort of locally advanced breast cancer patients, before and after neoadjuvant chemotherapy (NAC). From a panel of tested proteins and genes, we found that the levels of plasma NRP-1, placenta growth factor (PlGF) and immune cell expression of the transcription factor SNAI1 before and after NAC were significantly different. Paired t-test analysis of 22 locally advanced breast cancer patients showed that plasma NRP-1 levels were increased significantly (p = 0.018) post-NAC in patients with pathological partial response (pPR). Kaplan–Meier analysis indicated that patients who received NAC cycles and their excised tumors remained with high levels of NRP-1 had a lower overall survival compared with patients whose tissue NRP-1 decreased post-NAC (log-rank p = 0.049). In vitro validation of the former result showed an increase in the secreted and cellular NRP-1 levels in resistant MDA-MB-231 cells to the most common NAC regimen Adriyamicin/cyclophosphamide+Paclitaxel (AC+PAC). In addition, NRP-1 knockdown in MDA-MB-231 cells sensitized the cells to AC and more profoundly to PAC treatment and the cells sensitivity was proportional to the expressed levels of NRP-1. Unlike NRP-1, circulating PlGF was significantly increased (p = 0.014) in patients with a pathological complete response (pCR). SNAI1 expression in immune cells showed a significant increase (p = 0.018) in patients with pCR, consistent with its posited protective role. We conclude that increased plasma and tissue NRP-1 post-NAC correlate with pPR and shorter overall survival, respectively. These observations support the need to consider anti-NRP-1 as a potential targeted therapy for breast cancer patients who are identified with high NRP-1 levels. Meanwhile, the increase in both PlGF and SNAI1 in pCR patients potentially suggests their antitumorigenic role in breast cancer that paves the way for further mechanistic investigation to validate their role as potential predictive markers for pCR in breast cancer.

RNA binding protein PUM2 promotes the stemness of breast cancer cells via competitively binding to neuropilin-1 (NRP-1) mRNA with miR-376a

Others and ours studies have established the promoting roles of NRP-1 (neuropilin-1) in breast cancer, however, the underlying mechanisms by which NRP-1 is regulated are still confused. Here, bioinformatics analysis indicated that RNA binding protein PUM2 could bind to NRP-1 mRNA. Clinical samples showed that PUM2 expression was significantly increased in breast cancer tissues, negatively correlated with the overall survival and relapse-free survival of breast cancer patients, and positively correlated with NRP-1 expression. Meanwhile, PUM2 expression was remarkably increased in non-adherent spheroids. in vitro experiments demonstrated that PUM2 knockdown attenuated the stemness of breast cancer cells, evident by the decrease of spheroid formation capacity, ALDH1 activity and stemness marker expression. Mechanistically, RNA immunoprecipitation (RIP) and luciferase reporter analysis indicated that PUM2 competitively bound to NRP 3'UTR with miR-376a, which had been previously confirmed by us to suppress the stemness of breast cancer cells, and increased NRP-1 mRNA stability and expression. Furthermore, ectopic expression of NRP-1 or miR-376a knockdown rescued the inhibitory effects of NRP-1 knockdown on the stemness of breast cancer cells. Thus, our results suggest that PUM2 could facilitate the stemness of breast cancer cells by competitively binding to NRP-1 3'UTR with miR-376a.

Neuropilins in the Context of Tumor Vasculature

Neuropilin-1 and Neuropilin-2 form a small family of plasma membrane spanning receptors originally identified by the binding of semaphorin and vascular endothelial growth factor. Having no cytosolic protein kinase domain, they function predominantly as co-receptors of other receptors for various ligands. As such, they critically modulate the signaling of various receptor tyrosine kinases, integrins, and other molecules involved in the regulation of physiological and pathological angiogenic processes. This review highlights the diverse neuropilin ligands and interacting partners on endothelial cells, which are relevant in the context of the tumor vasculature and the tumor microenvironment. In addition to tumor cells, the latter contains cancer-associated fibroblasts, immune cells, and endothelial cells. Based on the prevalent neuropilin-mediated interactions, the suitability of various neuropilin-targeted substances for influencing tumor angiogenesis as a possible building block of a tumor therapy is discussed.