Brain metastasis-related microRNAs in patients with advanced breast cancer

Recent advances in breast cancer metastasis with special emphasis on metastasis to the brain

Understanding the underlying mechanisms of breast cancer metastasis is of vital importance for developing treatment approaches. This review emphasizes contemporary breakthrough studies with special focus on breast cancer brain metastasis. Acquired mutational changes in metastatic lesions are often distinct from the primary tumor, suggesting altered mutagenesis pathways. The concept of micrometastases and heterogeneity within the tumors unravels novel therapeutic targets at genomic and molecular levels through epigenetic and proteomic profiling. Several pre-clinical studies have identified mechanisms involving the immune system, where tumor associated macrophages are key players. Expression of cell proteins like Syndecan1, fatty acid-binding protein 7 and tropomyosin kinase receptor B have been implicated in aiding the transmigration of breast cancer cells to the brain. Changes in the proteomic landscape of the blood-brain-barrier show altered permeability characteristics, supporting entry of cancer cells. Findings from laboratory studies pave the path for the emergence of new biomarkers, especially blood-based miRNA and circulating tumor cell markers for prognostic staging. The constantly evolving therapeutics call for clinical trials backing supportive evidence of efficacies of both novel and existing approaches. The challenge lying ahead is discovering innovative techniques to replace use of human samples and optimize small-scale patient recruitment in trials.

Prospects for liquid biopsy using microRNA and extracellular vesicles in breast cancer

Among the analytes circulating in body fluids, microRNAs, a type of non-coding RNA and known to exist 2655 in primates, have attracted attention as a novel biomarker for cancer screening. MicroRNAs are signaling molecules with important gene expression regulatory functions that can simultaneously control many gene functions and multiple different pathways in living organisms. These microRNAs are transported in extracellular vesicles (EVs), which are lipid bilayers with 50-150 nm in diameter, and are used as communication tools between cells. Furthermore, the EVs that carry these microRNAs circulate in the bloodstream and have other important implications for understanding the pathogenesis and diagnosis of breast cancer. The greatest benefit from cancer screening is the reduction in breast cancer mortality rate through early detection. Other benefits include reduced incidence of breast cancer, improved quality of life, prognosis prediction, contribution to personalized medicine, and relative healthcare cost containment. This paper outlines the latest developments in liquid biopsy for breast cancer, especially focusing on microRNA and EV diagnostics.

New insights of miRNA molecular mechanisms in breast cancer brain metastasis and therapeutic targets

Brain metastases in breast cancer (BC) patients are often associated with a poor prognosis. Recent studies have uncovered the critical roles of miRNAs in the initiation and progression of BC brain metastasis, highlighting the disease's underlying molecular pathways. miRNA-181c, miRNA-10b, and miRNA-21, for example, are all overexpressed in BC patients. It has been shown that these three miRNAs help tumors grow and metastasize by targeting genes that control how cells work. On the other hand, miRNA-26b5p, miRNA-7, and miRNA-1013p are all downregulated in BC brain metastasis patients. They act as tumor suppressors by controlling the expression of genes related to cell adhesion, angiogenesis, and invasion. Therapeutic miRNA targeting has considerable promise in treating BC brain metastases. Several strategies have been proposed to modulate miRNA expression, including miRNA-Mimics, antagomirs, and small molecule inhibitors of miRNA biogenesis. This review discusses the aberrant expression of miRNAs and metastatic pathways that lead to the spread of BC cells to the brain. It also explores miRNA therapeutic target molecular mechanisms and BC brain metastasis challenges with advanced strategies. The targeting of certain miRNAs opens a new door for the development of novel therapeutic approaches for this devastating disease.

Organ-Specificity of Breast Cancer Metastasis

Breast cancer (BC) remains one of the most common malignancies among women worldwide. Breast cancer shows metastatic heterogeneity with priority to different organs, which leads to differences in prognosis and response to therapy among patients. The main targets for metastasis in BC are the bone, lung, liver and brain. The molecular mechanism of BC organ-specificity is still under investigation. In recent years, the appearance of new genomic approaches has led to unprecedented changes in the understanding of breast cancer metastasis organ-specificity and has provided a new platform for the development of more effective therapeutic agents. This review summarises recent data on molecular organ-specific markers of metastasis as the basis of a possible therapeutic approach in order to improve the diagnosis and prognosis of patients with metastatically heterogeneous breast cancer.

Cell-Free miRNAs as Non-Invasive Biomarkers in Brain Tumors

Diagnosing brain tumors, especially malignant variants, such as glioblastoma, medulloblastoma, or brain metastasis, presents a considerable obstacle, while current treatment methods often yield unsatisfactory results. The monitoring of individuals with brain neoplasms becomes burdensome due to the intricate tumor nature and associated risks of tissue biopsies, compounded by the restricted accuracy and sensitivity of presently available non-invasive diagnostic techniques. The uncertainties surrounding diagnosis and the tumor's reaction to treatment can lead to delays in critical determinations that profoundly influence the prognosis of the disease. Consequently, there exists a pressing necessity to formulate and validate dependable, minimally invasive biomarkers that can effectively diagnose and predict brain tumors. Cell-free microRNAs (miRNAs), which remain stable and detectable in human bodily fluids, such as blood and cerebrospinal fluid (CSF), have emerged as potential indicators for a range of ailments, brain tumors included. Numerous investigations have showcased the viability of profiling cell-free miRNA expression in both CSF and blood samples obtained from patients with brain tumors. Distinct miRNAs demonstrate varying expression patterns within CSF and blood. While cell-free microRNAs in the blood exhibit potential in diagnosing, prognosticating, and monitoring treatment across diverse tumor types, they fall short in effectively diagnosing brain tumors. Conversely, the cell-free miRNA profile within CSF demonstrates high potential in delivering precise and specific evaluations of brain tumors.

An Overview of Circulating Biomarkers in Neuroendocrine Neoplasms: A Clinical Guide

Neuroendocrine neoplasms (NENs) are a heterogeneous group of diseases that are characterized by different behavior and clinical manifestations. The diagnosis and management of this group of tumors are challenging due to tumor complexity and lack of precise and widely validated biomarkers. Indeed, the current circulating mono-analyte biomarkers (such as chromogranin A) are ineffective in describing such complex tumors due to their poor sensitivity and specificity. In contrast, multi-analytical circulating biomarkers (including NETest) are emerging as more effective tools to determine the real-time profile of the disease, both in terms of accurate diagnosis and effective treatment. In this review, we will analyze the capabilities and limitations of different circulating biomarkers focusing on three relevant questions: (1) accurate and early diagnosis; (2) monitoring of disease progression and response to therapy; and (3) detection of early relapse.

microRNAs signature in relapse metastasis and de novo metastasis of breast cancer. A systematic review

miRNAs have been widely identified as important players in cancer development and progression. Metastasis in breast cancer can occur as relapse of a treated primary tumour or at the time of diagnosis of the tumour. The aim of this review is to show if both metastasis are different molecular entities characterised by different miRNA signatures that could be studied as specific biomarkers for each entity. For this, we systematically searched the PubMed, Scopus and Web of Science databases. After searching and reviewing the literature, a total of 30 records were included in this review. Results showed a genetic signature including a total of 5 upregulated miRNAs in metastasis compared with early stages. Of them, miR-23b and miR-200c were exclusively present in relapse metastasis. Finally, we proposed a molecular signature for future studies that can be used as a complementary tool at clinical trials for the diagnosis and characterization of metastasis.

Liquid biopsy for brain metastases and leptomeningeal disease in patients with breast cancer

A significant subset of patients with metastatic breast cancer develops brain metastasis. As efficacy of systemic therapies has improved and patients live longer with metastatic breast cancer, the incidence of breast cancer brain metastases has increased. Brain metastases pose a clinical challenge in diagnosis, treatment, and monitoring across all breast cancer subtypes, and better tools are needed. Liquid biopsy, which enables minimally invasive sampling of a patient's cancer, has the potential to shed light on intra-cranial tumor biology and to improve patient care by enabling therapy tailoring. Here we review current evidence for the clinical validity of liquid biopsy in patients with breast cancer brain metastases, with a focus on circulating tumor cells and circulating tumor DNA.

Potential miRNA Use as a Biomarker: From Breast Cancer Diagnosis to Metastasis

Breast cancer is the most common cancer in women. Despite advances in diagnosis and prognosis, distal metastases occur in these patients in up to 15% of cases within 3 years of diagnosis. The main organs in which BC metastasises are the bones, lungs, liver, and brain. Unfortunately, 90% of metastatic patients will die, making this an incurable disease. Researchers are therefore seeking biomarkers for diagnosis and metastasis in different organs. Optimally, such biomarkers should be easy to detect using, preferably, non-invasive methods, such as using miRNA molecules, which are small molecules of about 22 nt that have as their main function the post-transcriptional regulation of genes. Furthermore, due to their uncomplicated detection and reproducibility in the laboratory, they are a tool of complementary interest for diagnosis, prognosis, and treatment. With this in mind, in this review, we focus on describing the most current studies that propose using miRNA independently as a potential biomarker for the diagnosis and prediction of brain, lung, liver, and bone metastases, as well as to open a window of opportunity to deepen this area of study to eventually use miRNAs molecules in clinical practice for the benefit of BC patients.

Prognostic value of microRNAs in patients with small cell lung cancer: a meta-analysis

BACKGROUND

An increasing number of studies have shown that microRNAs play an important role in the occurrence and development of small cell lung cancer, which mainly manifest as oncogenic and tumor inhibition. Therefore, microRNAs may affect the survival of patients with small cell lung cancer. In this meta-analysis, we will evaluate the role of microRNAs in the overall survival of patients with small cell lung cancer, which may provide valuable information for the treatment of small cell lung cancer.

METHODS

We searched the PubMed, Embase, and Web of Science online databases to determine the effect of microRNAs on the prognosis of patients with small cell lung cancer. The data and characteristics of each study were extracted, and the hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated to estimate the effect.

RESULTS

A total of 7 articles, involving 427 subjects and 15 studies, were included in this meta-analysis. The pooled HR of the relationship between the microRNA expression level and the overall survival rate of small cell lung cancer patients was 1.25 (95% CI: 1.06-1.47). There was a significant difference in the prognostic value of oncogenic and tumor inhibition microRNAs among patients with small cell lung cancer, with pooled HRs of 1.60 (95% CI: 1.35-1.90) and 0.42 (95% CI: 0.30-0.57), respectively.

CONCLUSIONS

MicroRNAs have a significant impact on the overall survival of small cell lung cancer patients, suggesting that microRNAs can be used as potential prognostic markers and may provide treatment strategies for small cell lung cancer patients.

TRIAL REGISTRATION

The protocol was registered on PROSPERO website with the registration number of CRD42022334363. The relevant registration information can be obtained from the website https://www.crd.york.ac.uk/prospero/#searchadvanced .

Innovative Approaches for Breast Cancer Metastasis to the Brain

Breast cancer metastasis is a continued concern for patients with recent development in our understanding of disease progression. In this paper, we highlight the pathophysiology behind breast cancer metastasis. Blood brain barrier disruption plays a critical component in progression. We then investigate the current treatment strategies and recommended guidelines. This focuses on radiation and medical management. Finally, we address the role of surgical intervention. The data is organized into tables and figures to highlight key components. Finally, we address emerging treatments and pre-clinical data. The paper will serve as a user-friendly guide for clinicians and researchers to help formulate a strategy to manage breast cancer metastasis patients sufficiently.

Efficacy and Risk Factors of Pyrrotinib in Second- and Third-Line Treatments for HER2-Positive Advanced Breast Cancer

A study to examine the efficacy and risk factors associated with pyrrotinib in the second- and third-line treatment of advanced breast cancer with Human epidermal growth factor receptor 2- (HER2-) positive cells was conducted. Progression-free survival (PFS) was assessed as the primary endpoint, and the objective response rate (ORR), overall survival (OS), and safety were secondary endpoints. Across all the patients, the ORR was 48.57%, and the disease control rate (DCR) was 94.29%. In the follow-up period, the median PFS was 15 months, and second-line treatment had significantly longer PFS than third-line treatment (P = 0.027). The OS among all the patients was up to 28 months, but the median OS has not yet been reached. Diarrhea (69.57%) was the most important AE, mainly in grades 1 and 2. According to the COX regression analysis, brain metastasis was a risk factor for PFS, while second-line treatment and capecitabine chemotherapy were relevant to a longer PFS correlation among patients. In the second- and third-line treatment, pyrrotinib is still highly effective and safe. Pyrrotinib is a potential ideal salvage treatment plan for patients who failed in first-line treatments.

A Drug Screening Reveals Minocycline Hydrochloride as a Therapeutic Option to Prevent Breast Cancer Cells Extravasation across the Blood-Brain Barrier

Among breast cancer (BC) patients, 15-25% develop BC brain metastases (BCBM), a severe condition due to the limited therapeutic options, which points to the need for preventive strategies. We aimed to find a drug able to boost blood-brain barrier (BBB) properties and prevent BC cells (BCCs) extravasation, among PI3K, HSP90, and EGFR inhibitors and approved drugs. We used BCCs (4T1) and BBB endothelial cells (b.End5) to identify molecules with toxicity to 4T1 cells and safe for b.End5 cells. Moreover, we used those cells in mixed cultures to perform a high-throughput microscopy screening of drugs' ability to ameliorate BBB properties and prevent BCCs adhesion and migration across the endothelium, as well as to analyse miRNAs expression and release profiles. KW-2478, buparlisib, and minocycline hydrochloride (MH) promoted maximal expression of the junctional protein β-catenin and induced 4T1 cells nucleus changes. Buparlisib and MH further decreased 4T1 adhesion. MH was the most promising in preventing 4T1 migration and BBB disruption, tumour and endothelial cytoskeleton-associated proteins modifications, and miRNA deregulation. Our data revealed MH's ability to improve BBB properties, while compromising BCCs viability and interaction with BBB endothelial cells, besides restoring miRNAs' homeostasis, paving the way for MH repurposing for BCBM prevention.

Prediction for Distant Metastasis of Breast Cancer Using Dynamic Contrast-Enhanced Magnetic Resonance Imaging Images under Deep Learning

This research aimed to explore the effect of using magnetic resonance imaging (MRI) radiomic features to establish a model for predicting distant metastasis under dynamic contrast-enhanced MRI imaging with deep learning algorithms. The deep learning algorithm was used to segment the images. A total of 96 cases with 100 lesions were included in the metastatic group, including 2 cases of bifocal breast cancer and 2 cases of multifocal breast cancer. There were 192 cases in the nonmetastatic group, with 197 lesions, including 5 cases of multifocal breast cancer. After dynamic contrast-enhancement, the morphological features and grayscale statistical features were extracted from the lesions to establish a prediction model through sum-sum check and feature dimension reduction. The accuracy, sensitivity, specificity, and area under receiver operator characteristic curve (AUC) of prediction models based only on imaging features were compared with those created by combining radiomic features with clinical and pathological features. The created predictive model based on radiomic features for distant metastases in breast cancer showed a sensitivity of 66.7%, a specificity of 84.2%, an accuracy of 78.3%, and an AUC of 0.744. The sensitivity of the prediction model for distant metastasis of breast cancer was 67.7%, the specificity was 86.8%, the accuracy was 80.5%, and the AUC was 0.763. Bone, lung, and liver were the most common distant metastatic sites of breast cancer. Under the dynamic contrast-enhanced MRI of deep learning, the prediction model combining radiomic features with clinical and pathological features showed better predictive performance.

LINC01806 mediated by STAT1 promotes cell proliferation, migration, invasion, and stemness in non-small cell lung cancer through Notch signaling by miR-4428/NOTCH2 axis

Background

Non-small cell lung cancer (NSCLC), the most primary lung cancer subtype, threatens human health globally. Long non-coding RNAs (lncRNAs) have been uncovered to affect multiple cancers progression. Nevertheless, the specific function of long intergenic non-protein coding RNA 1806 (LINC01806) in NSCLC remains elusive.

Methods

RT-qPCR and western blot were involved in this study. The influence of LINC01806 on NSCLC was assessed by in vitro and in vivo assays. Via ChIP, RNA pull down, RIP, and luciferase reporter assays, the in-depth cellular mechanisms of LINC01806 in NSCLC were explored.

Results

LINC01806 expression was high in NSCLC cell lines. Functionally, LINC01806 knockdown impeded cell proliferation, migration, invasion, and stemness, along with tumor growth. As for its mechanism, signal transducer and activator of transcription 1 (STAT1) activated LINC01806 transcription in NSCLC. Furthermore, LINC01806 sequestered microRNA-4428 (miR-4428) to enhance notch receptor 2 (NOTCH2) expression, thus activating Notch signaling pathway. Finally, in vitro and in vivo assays jointly validated that LINC01806 exerted its function in NSCLC development via miR-4428/NOTCH2 pathway.

Conclusion

LINC01806 enhanced NOTCH2 expression to stimulate Notch signaling via sponging miR-4428, thereby facilitating NSCLC progression, which provided a novel mechanism for NSCLC therapeutic approaches.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-022-02560-8.

Liquid biopsies to occult brain metastasis

Brain metastasis (BrM) is a major problem associated with cancer-related mortality, and currently, no specific biomarkers are available in clinical settings for early detection. Liquid biopsy is widely accepted as a non-invasive method for diagnosing cancer and other diseases. We have reviewed the evidence that shows how the molecular alterations are involved in BrM, majorly from breast cancer (BC), lung cancer (LC), and melanoma, with an inception in how they can be employed for biomarker development. We discussed genetic and epigenetic changes that influence cancer cells to breach the blood-brain barrier (BBB) and help to establish metastatic lesions in the uniquely distinct brain microenvironment. Keeping abreast with the recent breakthroughs in the context of various biomolecules detections and identifications, the circulating tumor cells (CTC), cell-free nucleotides, non-coding RNAs, secretory proteins, and metabolites can be pursued in human body fluids such as blood, serum, cerebrospinal fluid (CSF), and urine to obtain potential candidates for biomarker development. The liquid biopsy-based biomarkers can overlay with current imaging techniques to amplify the signal viable for improving the early detection and treatments of occult BrM.

Mesenchymal stem cell-derived exosome mir-342-3p inhibits metastasis and chemo-resistance of breast cancer through regulating ID4

BACKGROUND

The mesenchymal stem cell-derived exosome (MSCs-exo) carrying microRNAs have been proved to regulate tumor biological activities. Clarifying molecular mechanism and identifying predictive microRNAs will be of great value in anti-tumor therapy improvement.

OBJECTIVE

We aimed to investigate the regulatory role of microRNA-342-3p (miR-342-3p) in MSCs-exo on breast cancer.

METHODS

Breast cancer tissues and cell lines were used to evaluate miR-342-3p expression in patients with or without lymph node/distal organ metastasis. The impact of MSCs-exo expression on tumor cell chemo-resistance and invasion/migration was measured. Dual-luciferase reporter gene assay was applied to identify binding site. Inhibitor of differentiation 4 (ID4) siRNA and miR-342-3p inhibitor transfection was conducted to further explore the miR-342-3p/ID4 axis on chemo-resistance and metastasis of breast cancer cells.

RESULTS

Breast cancer cells revealed significantly lower level of miR-342-3p in patients with metastatic diseases. miR-342-3p suppressed invasive and chemo-resistant behavior of breast cancer tumor cells. Binding site between miR-342-3p and ID4 was proved. ID4 could reverse the influence of miR-342-3p on chemo-resistance. The tumor inhibition effect of IDA siRNA in vivo was also identified.

CONCLUSIONS

This study demonstrated that miR-342-3p acted as potential tumor suppressor by inhibiting metastasis and chemo-resistance of breast cancer cells through targeting ID4. This study might provide potential therapy targets for the treatment of breast cancer.

Serum microRNA as liquid biopsy biomarker for the prediction of oncological outcomes in patients with bladder cancer

OBJECTIVES

Radical cystectomy is the gold-standard treatment for muscle-invasive bladder cancer and aggressive non-muscle-invasive bladder cancer. To enhance clinical decision-making regarding patients with bladder cancer who underwent radical cystectomy, a recurrence prediction biomarker with high accuracy is urgently needed. In this study, we developed a model for the prediction of bladder cancer recurrence after radical cystectomy by combining serum microRNA and a pathological factor.

METHODS

We retrospectively analyzed the clinical records of 81 patients with bladder cancer who underwent radical cystectomy between 2008 and 2016. The dataset was divided into two, and Fisher linear discriminant analysis was used to construct a prognostic model for future recurrence in the training set (n = 41). The performance of the model was evaluated in the validation set (n = 40).

RESULTS

Thirty patients had recurrence after having undergone radical cystectomy. A prognostic model for recurrence was constructed by combining a pathological factor (i.e. positive pathological lymph node status) and three microRNAs (miR-23a-3p, miR-3679-3p, and miR-3195). The model showed a sensitivity of 0.87, a specificity of 0.80, and an area under the receiver operating characteristic curve of 0.88 (0.77-0.98) in the validation set. Furthermore, Kaplan-Meier analysis revealed that patients with a low prediction index have significantly longer overall survival than patients with a high prediction index (P = 0.041).

CONCLUSION

A combination of serum microRNA profiles and lymph node statuses is useful for the prediction of oncological outcomes after radical cystectomy in patients with bladder cancer.

miRNAs in Cancer (Review of Literature)

MicroRNAs (miRNAs) are short, noncoding, single-stranded RNA molecules that regulate gene expression at the post-transcriptional level by binding to mRNAs. miRNAs affect the course of processes of fundamental importance for the proper functioning of the organism. These processes include cell division, proliferation, differentiation, cell apoptosis and the formation of blood vessels. Altered expression of individual miRNAs has been shown in numerous cancers, which may indicate the oncogenic or suppressor potential of the molecules in question. This paper discusses the current knowledge about the possibility of using miRNA as a diagnostic marker and a potential target in modern anticancer therapies.

Emerging Biomarkers for Diagnosis, Prevention and Treatment of Brain Metastases-From Biology to Clinical Utility

Primary malignancies of the lung, skin (melanoma), and breast have higher propensity for metastatic spread to the brain. Advances in molecular tumour profiling have aided the development of targeted therapies, stereotactic radiotherapy, and immunotherapy, which have led to some improvement in patient outcomes; however, the overall prognosis remains poor. Continued research to identify new prognostic and predictive biomarkers is necessary to further impact patient outcomes, as this will enable better risk stratification at the point of primary cancer diagnosis, earlier detection of metastatic deposits (for example, through surveillance), and more effective systemic treatments. Brain metastases exhibit considerable inter- and intratumoural heterogeneity-apart from distinct histology, treatment history and other clinical factors, the metastatic brain tumour microenvironment is incredibly variable both in terms of subclonal diversity and cellular composition. This review discusses emerging biomarkers; specifically, the biological context and potential clinical utility of tumour tissue biomarkers, circulating tumour cells, extracellular vesicles, and circulating tumour DNA.

Clinical Biomarkers for Early Identification of Patients with Intracranial Metastatic Disease

Simple Summary

The development of brain metastases, or intracranial metastatic disease (IMD), is a serious and life-altering complication for many patients with cancer. While there have been substantial advancements in the treatments available for IMD and in our understanding of its pathogenesis, conventional methods remain insufficient to detect IMD at an early stage. In this review, we discuss current research on biomarkers specific to IMD. In particular, we highlight biomarkers that can be easily accessed via the bloodstream or cerebrospinal fluid, including circulating tumor cells and DNA, as well as advanced imaging techniques. The continued development of these assays could enable clinicians to detect IMD prior to the development of IMD-associated symptoms and ultimately improve patient prognosis and survival.

Abstract

Nearly 30% of patients with cancer will develop intracranial metastatic disease (IMD), and more than half of these patients will die within a few months following their diagnosis. In light of the profound effect of IMD on survival and quality of life, there is significant interest in identifying biomarkers that could facilitate the early detection of IMD or identify patients with cancer who are at high IMD risk. In this review, we will highlight early efforts to identify biomarkers of IMD and consider avenues for future investigation.

MicroRNA-550a-3-5p controls the brain metastasis of lung cancer by directly targeting YAP1

Background

This study aimed to explore the potential regulatory mechanisms of brain metastasis and to identify novel underlying targets of lung cancer with brain metastasis.

Methods

Exosomes were isolated from the plasma of lung cancer patients with or without brain metastasis and low or high metastatic lung cancer cells, and small RNA from plasma-derived exosomes were sequenced. Differentially expressed miRNAs (DE-miRNAs) were identified. Human brain microvascular endothelial cells (HBMECs) were transfected with miR-550a-3-5p mimics or inhibitors and exosomes. Cell viability, migration, and apoptosis/cycle were determined using Cell Counting Kit-8 (CCK-8), Transwell, and flow cytometry, respectively. Western blotting was used to measure the expression of the associated proteins. Finally, a dual-luciferase reporter gene assay was performed to confirm the miR-550a-3-5p target.

Results

Transmission electron microscopy, NanoSight, and western blotting showed that exosomes were successfully isolated and cell-derived exosomes could be taken up by HBMECs. Sequencing identified 22 DE-miRNAs which were enriched in the MAPK, chemokine, PPAR, and Wnt signaling pathways. MiR-550a-3-5p was significantly enriched in brain metastatic exosomes. Cellular experiments showed that miR-550a-3-5p and exosome enrichment significantly inhibited cell viability and migration, promoted apoptosis, and regulated the cell cycle of HBMECs compared with the controls (P  <  0.05). Compared with the controls, high levels of both miR-550a-3-5p and exosomes markedly upregulated cleaved-PARP expression, but downregulated the expression of pRB, CDK6, YAP1, CTGF, and CYR61 (P  <  0.05). Finally, YAP1 was confirmed to bind directly to miR-550a-3-5p.

Conclusion

Our results indicate that miR-550a-3-5p and YAP1 may be novel potential targets for controlling brain metastasis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02197-z.

Comparison of pyrotinib or lapatinib with chemotherapy for patients with HER2 positive breast cancer after first-line treatment failure: a retrospective study

OBJECTIVE

To explore the difference in efficacy and safety of pyrotinib or lapatinib combined with chemotherapy in human epidermal growth factor receptor-2 (HER-2) positive breast cancer patients who failed the first-line trastuzumab-containing treatment.

METHODS

The present retrospective study included 164 HER-2 positive breast cancer patients admitted to our hospital. Among them, 68 cases received pyrotinib combined with chemotherapy after the failure of trastuzumab first-line treatment (pyrotinib group), and the other 96 cases received lapatinib combined chemotherapy (lapatinib group). The end of the follow-up time was set as June 1, 2020. The primary endpoint was progression free survival (PFS), and the secondary endpoints included best objective response rate (ORR) and safety.

RESULTS

Till the end of the follow-up, the best ORR (60.3% vs. 34.4%) in the pyrotinib group was significantly higher than that in the lapatinib group, and the median PFS (9.0 months vs. 6.2 months) was also largely prolonged (P<0.01). In addition, the median PFS of the patients with brain metastases in the pyrotinib group was 6.5 months, and was much longer that in the lapatinib group which wereth 3.5 months in length (P<0.05). Multivariate COX regression analysis showed that pyrotinib combined with chemotherapy (HR=0.653, P<0.05) was associated with longer PFS of patients, while the lapatinib group had a higher proportion of vomiting and hand foot syndrome than the pyrotinib group (P<0.05).

CONCLUSION

After the failure of first-line trastuzumab-containing treatment, combination of pyrotinib with chemotherapy has more significant short-term efficacy in HER-2 positive breast cancer patients than lapatinib combined with chemotherapy, especially in patients with brain metastasis.

Associations between lipids in selected brain regions, plasma miRNA, and behavioral and cognitive measures following 28Si ion irradiation

The space radiation environment consists of multiple species of charged particles, including 28Si ions, that may impact brain function during and following missions. To develop biomarkers of the space radiation response, BALB/c and C3H female and male mice and their F2 hybrid progeny were irradiated with 28Si ions (350 MeV/n, 0.2 Gy) and tested for behavioral and cognitive performance 1, 6, and 12 months following irradiation. The plasma of the mice was collected for analysis of miRNA levels. Select pertinent brain regions were dissected for lipidomic analyses and analyses of levels of select biomarkers shown to be sensitive to effects of space radiation in previous studies. There were associations between lipids in select brain regions, plasma miRNA, and cognitive measures and behavioral following 28Si ion irradiation. Different but overlapping sets of miRNAs in plasma were found to be associated with cognitive measures and behavioral in sham and irradiated mice at the three time points. The radiation condition revealed pathways involved in neurodegenerative conditions and cancers. Levels of the dendritic marker MAP2 in the cortex were higher in irradiated than sham-irradiated mice at middle age, which might be part of a compensatory response. Relationships were also revealed with CD68 in miRNAs in an anatomical distinct fashion, suggesting that distinct miRNAs modulate neuroinflammation in different brain regions. The associations between lipids in selected brain regions, plasma miRNA, and behavioral and cognitive measures following 28Si ion irradiation could be used for the development of biomarker of the space radiation response.

miR-543 impairs cell proliferation, migration, and invasion in breast cancer by suppressing VCAN

Breast cancer (BC) continues to plague millions of people worldwide. MicroRNAs have been observed to be closely associated with many cancers and may serve as promising biomarkers for the diagnosis of BC. BC tissue samples were collected from 26 patients, and qRT-PCR and western blotting were performed to evaluate the levels of miR-543 and VCAN. The action of miR-543 and VCAN was determined using CCK-8, BrdU, wound healing, and transwell invasion assays. Luciferase and RNA pull-down assays were used to assess whether miR-543 bound to VCAN. We found that miR-543 inhibited BC cell viability, proliferation, migration, and invasion by repressing the expression of VCAN. VCAN was upregulated in BC tissues and exerted beneficial effects on the development process of BC. Our results highlighted that the miR-543/VCAN axis is a promising diagnostic and prognostic biomarker in clinical applications.

Analysis of extracellular vesicles as a potential index for monitoring differentiation of neural lineage cells from induced pluripotent stem cells

To improve cell production efficacy, it is important to evaluate cell conditions during culture. Extracellular vesicles (EVs) secreted from various cells are involved in stem cell differentiation. As EVs carry information about their source cells, we hypothesized that they may serve as a noninvasive index of cell conditions. We evaluated changes in EV morphology, concentration, and microRNA (miRNA) and protein expression in culture supernatants during the differentiation of induced pluripotent stem cells (iPSCs) into neural lineage cells, for application in regenerative medicine for Parkinson's disease. We observed EVs (50-150 nm) in culture supernatants of iPSCs and differentiated cells. The EVs expressed the exosome markers CD63, CD81, and CD9. Throughout differentiation, the EV concentration in the supernatants decreased, and EV miRNA and protein expression changed substantially. Especially, miR-106b, involved in neural stem cell differentiation and normal brain development, was considerably downregulated. CD63 expression correlated with the CORIN-positive cell rate, which is an index of differentiation. Thus, EV concentration and miRNA and protein expression may reflect the differentiation status of iPSCs. These findings pave the way for the development of novel and sensitive cell culture monitoring methods.

Liquid Biomarkers for Improved Diagnosis and Classification of CNS Tumors

Liquid biopsy, as a non-invasive technique for cancer diagnosis, has emerged as a major step forward in conquering tumors. Current practice in diagnosis of central nervous system (CNS) tumors involves invasive acquisition of tumor biopsy upon detection of tumor on neuroimaging. Liquid biopsy enables non-invasive, rapid, precise and, in particular, real-time cancer detection, prognosis and treatment monitoring, especially for CNS tumors. This approach can also uncover the heterogeneity of these tumors and will likely replace tissue biopsy in the future. Key components of liquid biopsy mainly include circulating tumor cells (CTC), circulating tumor nucleic acids (ctDNA, miRNA) and exosomes and samples can be obtained from the cerebrospinal fluid, plasma and serum of patients with CNS malignancies. This review covers current progress in application of liquid biopsies for diagnosis and monitoring of CNS malignancies.

miRNAs in Health and Disease: A Focus on the Breast Cancer Metastatic Cascade towards the Brain

MicroRNAs (miRNAs) are small non-coding RNAs that mainly act by binding to target genes to regulate their expression. Due to the multitude of genes regulated by miRNAs they have been subject of extensive research in the past few years. This state-of-the-art review summarizes the current knowledge about miRNAs and illustrates their role as powerful regulators of physiological processes. Moreover, it highlights their aberrant expression in disease, including specific cancer types and the differential hosting-metastases preferences that influence several steps of tumorigenesis. Considering the incidence of breast cancer and that the metastatic disease is presently the major cause of death in women, emphasis is put in the role of miRNAs in breast cancer and in the regulation of the different steps of the metastatic cascade. Furthermore, we depict their involvement in the cascade of events underlying breast cancer brain metastasis formation and development. Collectively, this review shall contribute to a better understanding of the uniqueness of the biologic roles of miRNAs in these processes, to the awareness of miRNAs as new and reliable biomarkers and/or of therapeutic targets, which can change the landscape of a poor prognosis and low survival rates condition of advanced breast cancer patients.

Circulating microRNAs: Next-generation Cancer Detection

Early detection of cancer is crucial for its ultimate control and the prevention of malignant progression. In Japan, a nationwide project was conducted between 2014 and 2019 to develop novel cancer detection tools using serum microRNAs (miRNAs). Using the National Cancer Center Biobank, we collected more than 10,000 serum samples from patients with malignant diseases, including rare cancers such as ovarian cancer, gliomas, and sarcomas. Subsequently, comprehensive miRNA microarray analyses were performed for all samples. This serum miRNA database provides insights regarding miRNA biomarker candidates for each cancer type. Here, we summarize the major achievements of this national project. Notably, although circulating miRNAs packaged in extracellular vesicles are thought to be a cell-to-cell communication tool, the functional characteristics of the miRNAs listed in the project are still unknown. We hope that our findings will help elucidate the biological functions of circulating miRNAs.

Targeting PIK3CG in Combination with Paclitaxel as a Potential Therapeutic Regimen in Claudin-Low Breast Cancer

Purpose

Molecular targeting is a powerful approach for aggressive claudin-low breast cancer (CLBC). Overexpression of PI3K catalytic subunit gamma (PIK3CG) in human CLBC is offering a promising opportunity for targeted therapies. We utilized a specific inhibitor of PIK3CG combined with paclitaxel (PTX) to treat CLBC cells in vitro and in vivo.

Patients and Methods

The tumor cells growth and apoptosis in vitro were analyzed by CCK8, plate clone formation assay, tumorsphere assay, Hoechst staining and flow cytometry. The invasion and metastasis ability of tumor cells in vitro were investigated by wound healing and transwell experiments. Critical gene expression levels were checked by qRT-PCR and Western blot. Xenograft models with CLBC cell lines in SCID mice were established to investigate the effect of combined drugs in vivo.

Results

We identified that PIK3CG was a potential therapeutic target for CLBC patients. Targeting PIK3CG potentiated CLBC cells growth inhibition in 2D and 3D cultures by PTX. Inhibition of PIK3CG activation could enhance CLBC cells apoptosis and migration suppression induced by PTX. Manipulating autophagy was a validated approach for the use of PIK3CG inhibitor. Using CLBC xenograft mice model, we found that CLBC tumors in vivo could be well treated by combined drugs of PIK3CG inhibitor and PTX.

Conclusion

We demonstrated that PIK3CG was a potential target for the therapy of CLBC and inhibition of PIK3CG activation could reinforce the therapeutic effect of this aggressive disease by PTX. The combined use of PIK3CG inhibitor and PTX might be a potential regimen for treating this subtype of breast cancer.