A Comparative Analysis of the Immunoglobulin Repertoire in Leukemia Cells and B Cells in Chinese Acute Myeloid Leukemia by High-Throughput Sequencing.

It is common knowledge that immunoglobulin (Ig) is produced by B lymphocytes and mainly functions as an antibody. However, it has been shown recently that myeloblasts from acute myeloid leukemia (AML) could also express Ig and that AML-Ig played a role in leukemogenesis and AML progression. The difference between Ig from myeloblasts and B cells has not been explored. Studying the characteristics of the Ig repertoire in myeloblasts and B cells will be helpful to understand the function and significance of AML-Ig. We performed 5' RACE-related PCR coupled with PacBio sequencing to analyze the Ig repertoire in myeloblasts and B cells from Chinese AML patients. Myeloblasts expressed all five classes of IgH, especially Igγ, with a high expression frequency. Compared with B-Ig in the same patient, AML-Ig showed different biased V(D)J usages and mutation patterns. In addition, the CDR3 length distribution of AML-Ig was significantly different from those of B-Ig. More importantly, mutations of AML-IgH, especially Igµ, Igα, and Igδ, were different from that of B-IgH in each AML patient, and the mutations frequently occurred at the sites of post-translational modification. AML-Ig has distinct characteristics of variable regions and mutations, which may have implications for disease monitoring and personalized therapy.

The Structure Characteristics and Function of Non B Cell-Derived Immunoglobulin.

According to classical immunology theory, immunoglobulin (Ig) is exclusively produced by differentiated B lymphocytes, which exhibit a typical tetrapeptide chain structure and are predominantly present on the surface of B cells and in bodily fluids. B-Ig is one of the critical effector molecules for humoral immune responses specifically recognising antigens and eliminating them. However, mounting evidence has demonstrated that Ig is widely expressed in non B lineage cells, especially malignant ones (referred to as non B-Ig). Interestingly, non B-Ig mainly resides in the cytoplasm and secretion, but to some extent on the cell surface. Furthermore non B-Ig not only displays a tetrapeptide chain structure but also shows free heavy chains and free light chains (FLCs). Additionally, Ig derived from non B cancer cell typically displays unique glycosylation modifications. Functionally, non B-Ig demonstrated diversity and versatility, showing antibody activity and cellular biological activity, such as promoting cell proliferation and survival, and it is implicated in cancer progression and some immune-related diseases, such as renal diseases.

CCDC134 facilitates T cell activation through the regulation of early T cell receptor signaling.

Modulation of surface T cell antigen receptor (TCR) expression is crucial for proper T cell development and maintenance of mature T cell function at steady state and upon stimulation. We previously determined that CCDC134 (coiled-coil domain containing 134), a cytokine-like molecule that served as a potential member of the γc cytokine family, contributes to antitumor responses by augmenting CD8+ T cell-mediated immunity. Here we show that T cell-specific deletion of Ccdc134 decreased peripheral mature CD4+ and CD8+ T cells, which resulted in impaired T cell homeostasis. Moreover, Ccdc134-deficient T cells exhibited an attenuated response to TCR stimulation in vitro, showing lower activation and proliferative capacity. This was further reflected in vivo, rendering mice refractory to T cell-mediated inflammatory and antitumor responses. More importantly, CCDC134 is associated with TCR signaling components, including CD3ϵ, and attenuated TCR signaling in Ccdc134-deficient T cells via altered CD3ϵ ubiquitination and degradation. Taken together, these findings suggest a role for CCDC134 as a positive regulator of TCR-proximal signaling and provide insight into the cell-intrinsic functional consequences of Ccdc134 deficiency in the attenuation of T cell-mediated inflammatory and antitumor responses.

Efficacy and safety of pyrotinib-containing regimen in the patients with HER2-positive metastatic breast cancer: A multicenter real-world study.

BACKGROUND: Pyrotinib, a novel irreversible epidermal growth factor receptor 2 (EGFR)/HER2 dual tyrosine kinase inhibitor, has shown promising antitumor efficacy with tolerable toxicity in HER2-positive metastatic breast cancer (MBC) in several clinical trials. However, the clinical trials do not usually well reflect the patients in real clinical settings. Despite several small-sample studies in real world, the data on pyrotinib as first-line and third-or-later-line treatment and the efficacy comparison of pyrotinib combined with different regimens are still lacking. Therefore, this study aimed to investigate the efficacy and safety of pyrotinib for the HER2-positive MBC in real world to replenish more comprehensive data. METHODS: A total of 172 HER2-positive MBC patients treated with pyrotinib-based therapy were recruited from multiple centers in nonclinical trial settings from September 2017 to June 2020. RESULTS: The median progression-free survival (mPFS) of 172 patients was 8.83 months. The patients, receiving first-line pyrotinib treatment, had the longest mPFS (20.93 months) compared with those receiving second-line (8.67 months, p = 0.0339) and third-or-later-line (7.13 months, p = 0.0075) treatments, respectively. Prior treatment with lapatinib (p = 0.012) and site of metastasis (visceral vs. nonvisceral) (p = 0.033) were the independent prognostic factors for PFS. The prior treatment with lapatinib compared with lapatinib-native treatment (5.96 vs. 10.97 months, p = 0.0036) and those with visceral metastasis compared with nonvisceral metastasis (8.40 vs. 23.70 months, p = 0.0138) had worse mPFS. Among 146 patients evaluated for efficacy, 2.1%, 58.9%, and 32.9% showed complete response, partial response, and stable disease, respectively. Adverse events occurred in 92.4% of the patients with 33.3% Grade 3 and higher adverse events and diarrhea (57.0%), anemia (44.8%), and leukopenia (40.7%) as the most frequent ones. CONCLUSIONS: Pyrotinib-containing regimen could effectively treat HER2-positive MBC with acceptable toxicity, including the patients who progressed after lapatinib treatment and with brain metastasis.

Potential Predictive and Prognostic Value of Biomarkers Related to Immune Checkpoint Inhibitor Therapy of Triple-Negative Breast Cancer.

As an aggressive subtype of breast cancer, triple-negative breast cancer (TNBC) is associated with poor prognosis and lack of effective therapy, except chemotherapy. In recent years, immunotherapy based on immune checkpoint (IC) inhibition has emerged as a promising therapeutic strategy in TNBC. TNBC has more tumor-infiltrating lymphocytes (TILs) and higher rate of mutation and programmed cell death ligand-1 (PD-L1) expression than other subtypes of breast cancer have. However, previous studies have shown that monotherapy has little efficacy and only some TNBC patients can benefit from immunotherapy. Therefore, it is important to identify biomarkers that can predict the efficacy of IC inhibitors (ICIs) in TNBC. Recently, various biomarkers have been extensively explored, such as PD-L1, TILs and tumor mutational burden (TMB). Clinical trials have shown that PD-L1-positive patients with advanced TNBC benefit from ICIs plus chemotherapy. However, in patients with early TNBC receiving neoadjuvant therapy, PD-L1 cannot predict the efficacy of ICIs. These inconsistent conclusions suggest that PD-L1 is the best to date but an imperfect predictive biomarker for efficacy of ICIs. Other studies have shown that advanced TNBC patients with TMB ≥10 mutations/Mb can achieve clinical benefits from pembrolizumab. TILs also have potential predictive value in TNBC. Here, we select some biomarkers related to ICIs and discuss their potential predictive and prognostic value in TNBC. We hope these biomarkers could help to identify suitable patients and realize precision immunotherapy.

Durable Effect of Pyrotinib and Metronomic Vinorelbine in HER2-Positive Breast Cancer With Leptomeningeal Disease: A Case Report and Literature Review.

Leptomeningeal metastases (LM) are rare and catastrophic for metastatic breast cancer (MBC). The prognosis of HER2-positive breast cancer (BC) with LM is extremely poor. There is no high-quality evidence of treatment regimens in HER2-positive BC with LM yet. Here, we present a case of LM in a 50-year-old woman with HER2-positive BC. Immunohistochemistry revealed invasive ductal carcinoma, estrogen receptor negative, progesterone receptor negative, HER2 3+, P53 positive 80%, and Ki-67 positive 35%. Reported for the first time, the patient was given pyrotinib-targeted therapy (400 mg, oral, every day), metronomic vinorelbine (40 mg, oral, three times a week), and intrathecal methotrexate (10 mg, infrequent and irregular use due to poor compliance) synchronously. The patient received and benefited from the treatment regimen for 16 months. And the quality of life, as self-reported, improved significantly. We also comprehensively summarized all the case reports, observational studies, and clinical trials related to HER2-positive BC with LM in the PubMed database and ClinicalTrials.gov. Intrathecal chemotherapy (methotrexate, cytarabine, thiotepa), intrathecal trastuzumab, whole-brain radiotherapy, and systemic therapy are commonly used treatment options according to a review of the literature and research. Pembrolizumab and trastuzumab deruxtecan (DS-8201) as novel drugs are promising in LM. Furthermore, trastuzumab emtansine (T-DM1) and tyrosine kinase inhibitors (TKIs) such as tucatinib and neratinib have exhibited good efficacy in HER2-positive BC with central nervous system (CNS) metastases and deserve further exploration. In our report, combining pyrotinib-targeted therapy with metronomic chemotherapy is a potential regimen, which has presented satisfactory therapeutic efficacy and also warrants additional investigation in HER2-positive BC with LM.

Survival analysis and nomogram for early-stage occult breast cancer with positive lymph nodes based on the SEER database.

Background: Occult breast cancer (OBC) is a rare type of breast cancer, which accounts for 0.3-1.0% of all breast cancers. However, the treatment of OBC remains controversial, especially the local treatment. We aimed to analyze the impact of different treatment and N stage on survival in early-stage OBC patients, and construct a nomogram to predict the prognosis. Methods: The data of patients with early-stage breast cancer were obtained from 17 registries in the Surveillance, Epidemiology, and End Results (SEER) database. Patient characteristics and breast cancer-specific survival (BCSS) were compared among the groups. Cox proportional risk models were used for both the univariate and multivariate analyses. Variables with a P value <0.07 in the univariate analysis were included in the multivariate analysis. The independent prognostic factors were included in the nomogram and validated internally. Results: A total of 492 early-stage OBC patients were randomized at a 7:3 ratio into the training cohort (n=348) and the testing cohort (n=144). N2+ stage patients had a worse prognosis than N1 stage patients (P=0.0051). Triple-negative breast cancer (TNBC) patients had the worst prognosis. Early-stage OBC patients benefited from surgery (P=0.0093) and radiotherapy (P=0.0102), but not chemotherapy (P=0.4030). An analysis of OBC patients with different N stages showed that in terms of treatment, N1 stage patients benefited from surgery (P=0.023), but did not benefit significantly from radiotherapy (P=0.0793), whereas N2+ stage patients benefited from radiotherapy (P=0.0098), but the benefit from surgery was not significant (P=0.1005). In the multivariate analysis, N stage, surgery, and radiotherapy remained statistically significant. Based on the results of the multivariate analysis, we constructed a nomogram for estimating the 3- and 5-year BCSS of OBC patients. The concordance index and the calibration plots show that our nomogram had sufficient accuracy and good coordination. Conclusions: N stage, surgery, and radiotherapy were identified as independent prognostic factors for OBC. We successfully constructed a nomogram using these independent risk factors and demonstrated that it could help predict the 3- and 5-year BCSS of OBC patients. Further data analyses need to be conducted to revise the treatment of early-stage OBC.

Ccdc134 deficiency impairs cerebellar development and motor coordination.

Coiled-coil domain containing 134 (CCDC134) has been shown to serve as an immune cytokine to exert antitumor effects and to act as a novel regulator of hADA2a to affect PCAF acetyltransferase activity. While Ccdc134 loss causes abnormal brain development in mice, the significance of CCDC134 in neuronal development in vivo is controversial. Here, we report that CCDC134 is highly expressed in Purkinje cells (PCs) at all developmental stages and regulates mammalian cerebellar development in a cell type-specific manner. Selective deletion of Ccdc134 in mouse neural stem cells (NSCs) caused defects in cerebellar morphogenesis, including a decrease in the number of PCs and impairment of PC dendritic growth, as well as abnormal granule cell development. Moreover, loss of Ccdc134 caused progressive motor dysfunction with deficits in motor coordination and motor learning. Finally, Ccdc134 deficiency inhibited Wnt signaling but increased Ataxin1 levels. Our findings provide evidence that CCDC134 plays an important role in cerebellar development, possibly through regulating Wnt signaling and Ataxin1 expression levels, and in controlling cerebellar function for motor coordination and motor learning, ultimately making it a potential contributor to cerebellar pathogenesis.

The Therapeutic Effectiveness of Neoadjuvant Trastuzumab Plus Chemotherapy for HER2-Positive Breast Cancer Can Be Predicted by Tumor-Infiltrating Lymphocytes and PD-L1 Expression.

INTRODUCTION: Neoadjuvant trastuzumab plus chemotherapy may affect programmed death-ligand 1 (PD-L1) expression and tumor-infiltrating lymphocytes (TILs) in HER2-positive breast cancer. Discordant results were shown on the correlation between PD-L1 expression or TILs and the effectiveness of neoadjuvant therapy in HER2-positive breast cancer patients. This study aimed to clarify the predictive value of PD-L1 expression and TILs in neoadjuvant therapy in patients with HER2-positive breast cancer. METHODS: HER2-positive breast cancer cases receiving neoadjuvant treatment (NAT; n = 155) were retrospectively collected from July 2013 to November 2018. Histopathologic analysis of TILs was performed on hematoxylin and eosin (H&E)-stained sections from pre- and post-NAT specimens. The TIL score as a categorical variable can be divided into high (≥30%) and low (<30%) categories. The expression of PD-L1 was detected by immunohistochemistry, and the percentage of positive membranous staining (at least 1%) in tumor cells (PD-L1+TC) and TILs (PD-L1+TILs) was scored. RESULTS: In our study, 87 patients received neoadjuvant chemotherapy alone and 68 received neoadjuvant trastuzumab plus chemotherapy. Multivariate logistic regression analysis confirmed that lymph node metastasis, high TILs, and PD-L1+TILs in pre-neoadjuvant therapy specimens were independent predictors of pathological complete response (pCR) in neoadjuvant therapy (p < 0.05, for all). Among all patients, TILs were increased in breast cancer tissues post-neoadjuvant therapy (p < 0.001). Consistent results were found in the subgroup analysis of the trastuzumab plus chemotherapy group and the chemotherapy alone group (p < 0.05, for both). In 116 non-pCR patients, PD-L1+TC was decreased in breast cancer tissues post-neoadjuvant therapy (p = 0.0219). Consistent results were found in 43 non-pCR patients who received neoadjuvant trastuzumab plus chemotherapy (p = 0.0437). However, in 73 non-pCR patients who received neoadjuvant chemotherapy, there was no significant difference in PD-L1+TC expression in pre- and post-neoadjuvant therapy specimens (p = 0.1465). On the other hand, in the general population, the neoadjuvant trastuzumab plus chemotherapy group, and the neoadjuvant chemotherapy group, PD-L1+TILs decreased after treatment (p < 0.05, for both). CONCLUSION: Higher TIL counts and PD-L1+TILs in pre-neoadjuvant therapy specimens and lymph node metastasis are independent predictors of pCR in patients with HER2-positive breast cancer treated with neoadjuvant therapy. TIL counts, PD-L1+TC, and PD-L1+TILs changed before and after neoadjuvant trastuzumab plus chemotherapy for HER2-positive breast cancer, which may suggest that, in HER2-positive breast cancer, neoadjuvant trastuzumab plus chemotherapy may stimulate the antitumor immune effect of the host, thereby preventing tumor immune escape.

Light but tough bio-inherited materials: Luffa sponge based nickel-plated composites.

Natural structural materials featuring fine hierarchical architectures often display remarkable mechanical properties. To inherit the microstructures of biological materials, nickel-plated luffa sponges were fabricated through electrochemical deposition using natural luffa sponges as templates. Four groups of samples were processed based on nickel electroless and electroplating, and then characterized by X-ray diffraction and optical/scanning electron microscopy. Axial compression tests were performed to characterize the mechanical properties of the nickel-plated samples to compare with those of the original natural sponges. Results showed that a uniform layer of nickel was formed on the luffa fibers by electroless plating; conversely, by electroplating the nickel only minimal deposits were found on the inner luffa wall due to the uneven current distribution over the surface of sponge. Accordingly, electroless plating was deemed to be far more effective for metal deposition of materials with complex structures, such as luffa sponge. Alkali treatments prior to plating were found to be critical for subsequent mechanical performance and energy absorption capacity. The mechanical properties of nickel-plated samples surpass those of original luffa sponges, with the enhancement efficiency, i.e., the ratio of specific stiffness and strength, being highest for electroless-plated samples with a prior alkali treatment. Specifically, their energy absorption capacity was far superior to that in other comparable materials. Using a power scaling law, an empirical relationship was derived which indicated that the bending-dominated behavior of the nickel-plated luffa sponges was similar to that of open-cell foams. We believe that other artificially "bio-inherited materials" could be successfully processed and developed in this manner. The superior properties of bio-inherited materials that we obtained in this work may provide inspiration for future research efforts on bio-inspired structural materials.

Nephroprotective effects of nebivolol in 2K1C rats through regulation of the kidney ROS-ADMA-NO pathway.

BACKGROUND: To evaluate the protective effect of nebivolol against kidney damage and elucidate the underlying mechanism in a two-kidney, one-clip (2K1C) rat model. METHODS: 2K1C rats were obtained by clipping left renal artery of male Wistar rats and were considered hypertensive when systolic blood pressure (SBP) was ≥160mmHg 4 weeks after surgery. The 2K1C hypertensive rats were divided into untreated, nebivolol (10mg/kg, ig), and atenolol (80mg/kg, ig) treatment groups. The treatments lasted for 8 weeks. SBP, kidney structure and function, plasma and kidney angiotensin (Ang) II, nitric oxide (NO), asymmetric dimethylarginine (ADMA), and the oxidant status were examined. Kidney protein expression of NADPH oxidase (Nox) isoforms and its subunit p22phox, nitric oxide synthase (NOS) isoforms, protein arginine N-methyltransferase (PRMT) 1, and dimethylarginine dimethylaminohydrolase (DDAH) 1 and 2 was tested by western blotting. RESULTS: Nebivolol and atenolol exerted similar hypotensive effects. However, atenolol had little effect while nebivolol significantly ameliorated the functional decline and structural damage in the kidney, especially in non-clipped kidney (NCK), which was associated with the reduction of Ang II in NCK. Moreover, nebivolol inhibited the NCK production of reactive oxygen species (ROS) by decreasing Nox2, Nox4, and p22phox expression. Further, nebivolol reduced the plasma and kidney ADMA levels by increasing DDAH2 expression and decreasing PRMT1 expression. Nebivolol also increased the NCK NO level by ameliorating the expression of kidney NOS isoforms. CONCLUSIONS: Our results demonstrated that long-term treatment with nebivolol had renoprotective effect in 2K1C rats partly via regulation of kidney ROS-ADMA-NO pathway.

Baicalein attenuates monocrotaline-induced pulmonary arterial hypertension by inhibiting vascular remodeling in rats.

BACKGROUND: Pulmonary arterial hypertension (PAH) is a devastating cardiopulmonary disorder characterized by elevated pulmonary arterial pressure (PAP) and right ventricular hypertrophy (RVH) driven by progressive vascular remodeling. Reversing adverse vascular remodeling is an important concept in the treatment of PAH. Endothelial injury, inflammation, and oxidative stress are three main contributors to pulmonary vascular remodeling. Baicalein is a natural flavonoid that has been shown to possess anti-proliferative, anti-inflammatory, anti-oxidative, and cardioprotective properties. We hypothesized that baicalein may prevent the progression of PAH and preserve the right heart function by inhibiting pulmonary arterial remodeling. METHODS: Male Sprague-Dawley rats were distributed randomly into 4 groups: control, monocrotaline (MCT)-exposed, and MCT-exposed plus baicalein treated rats (50 and 100 mg/kg/day for 2 weeks). Hemodynamic changes, RVH, and lung morphological features were examined on day 28. Apoptosis was determined by TUNEL staining, and the mRNA levels of tumor necrosis factor alpha (TNF-α), interleukin-1ß (IL-1ß), and IL-6 were detected by qRT-PCR. The changes in oxidative indicators, including malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were measured using corresponding commercial kits. The levels of Bax, Bcl-2, and cleaved caspase-3, and the activation of mitogen-activated protein kinase (MAPK) and NF-κB were assessed by western blotting. RESULTS: MCT induced an increase in hemodynamic parameters and RVH, which were attenuated by baicalein treatment. Baicalein also blocked MCT-induced pulmonary arterial remodeling. The levels of apoptotic (Bax/Bcl-2 ratio and cleaved caspase-3) and inflammatory (IL-6, TNF-α, and IL-1ß) biomarkers in lung tissue were lower in baicalein-treated groups. Baicalein also decreased MDA level, and increased SOD and GSH-Px activity in rat pulmonary tissue. Furthermore, baicalein inhibited MCT-induced activation of the MAPK and NF-κB pathways. CONCLUSION: Baicalein ameliorates MCT-induced PAH by inhibiting pulmonary arterial remodeling at least partially via the MAPK and NF-κB pathways in rats.

Dipotassium N-stearoyltyrosinate ameliorated pathological injuries in triple-transgenic mouse model of Alzheimer's disease.

Recently, anandamide (AEA) analogues have been well recognized for its potent neuroprotective effects in counteracting the deterioration of Alzheimer's disease (AD) brains through multiple pathological processes. In our previous studies, dipotassium N-stearoyltyrosinate (NSTK), an AEA analogue synthesized by our laboratory was reported to exert significant efficacy through multiple interventions. Within this study, the amyloid precursor protein (APP)SWE/presenilin-1 (PS1)M146V/TauP301L mouse (3×Tg-AD) model was used to explore further the neuroprotective effects of NSTK and its underlying mechanisms. NSTK could increase spontaneous locomotor activity in the open field and low anxiety-like behavior in the elevated plus maze, and improve the spatial memory deficits in the Morris water maze. The biochemical analysis suggested that NSTK could decrease Aß42 deposition, abnormal tau aggregation, and the expressions of p-APP Thr668, PS1 and p-tau Ser202/Thr205 in the hippocampus of 3×Tg-AD mice. Consistently, NSTK could reduce the level of malondialdehyde, increase the activity of superoxide dismutase and catalase. Up-regulation of Bcl-2, and down-regulation of BAX, caspase-3 and inflammatory cytokines also occurred in the hippocampus of 3×Tg-AD mice after treatment with NSTK. Thus, NSTK could intervene in multiple pathological processes of AD and would be a drug candidate against AD.

Overexpression of miR-18a negatively regulates myocyte enhancer factor 2D to increase the permeability of the blood-tumor barrier via Krüppel-like factor 4-mediated downregulation of zonula occluden-1, claudin-5, and occludin.

miR-18a represses angiogenesis and tumor evasion by weakening vascular endothelial growth factor and transforming growth factor-ß signaling to prolong the survival of glioma patients, although it is thought to be an oncogene. This study investigates the potential effects of miR-18a on the permeability of the blood-tumor barrier (BTB) and its possible molecular mechanisms. An in vitro BTB model was successfully established. The endogenous expression of miR-18a in glioma vascular endothelial cells (GECs) was significantly lower than that in normal vascular ECs, and the overexpression of miR-18a significantly increased the permeability of the BTB as well as downregulating the mRNA and protein expressions of tight junction-related proteins zonula occluden-1 (ZO-1), claudin-5, and occludin in GECs. Dual luciferase reporter assays revealed that miR-18a bound to the 3'-untranslated region (3'UTR) of myocyte enhancer factor 2D (MEF2D). The overexpression of both miR-18a and MEF2D with the 3'UTR significantly weakened the effect caused by miR-18a of decreasing the mRNA and protein expressions of ZO-1, claudin-5 and occludin and of increasing the permeability of the BTB. Chromatin immunoprecipitation showed that MEF2D could directly bind to KLF4 promoter. This study shows that miR-18a targets and negatively regulates MEF2D, which further regulates tight junction-related proteins ZO-1, claudin-5, and occludin through transactivation of KLF4 and, finally, changes the permeability of the BTB. MiR-18a should garner growing attention because it might serve as a potential target in opening the BTB and providing a new strategy for the treatment of gliomas.

MiR-18a increased the permeability of BTB via RUNX1 mediated down-regulation of ZO-1, occludin and claudin-5.

The purposes of this study were to investigate the possible molecular mechanisms of miR-18a regulating the permeability of blood-tumor barrier (BTB) via down-regulated expression and distribution of runt-related transcription factor 1 (RUNX1). An in vitro BTB model was established with hCMEC/D3 cells and U87MG cells to obtain glioma vascular endothelial cells (GECs). The endogenous expressions of miR-18a and RUNX1 were converse in GECs. The overexpression of miR-18a significantly impaired the integrity and increased the permeability of BTB, which respectively were detected by TEER and HRP flux assays, accompanied by down-regulated mRNA and protein expressions and distributions of ZO-1, occludin and claudin-5 in GECs. Dual-luciferase reporter assay was carried out and revealed RUNX1 is a target gene of miR-18a. Meanwhile, mRNA and protein expressions and distribution of RUNX1 were downregulated by miR-18a. Most important, miR-18a and RUNX1 could reversely regulate the permeability of BTB as well as the expressions and distributions of ZO-1, occludin and claudin-5. Finally, chromatin immunoprecipitation verified that RUNX1 interacted with "TGGGGT" DNA sequence in promoter region of ZO-1, occludin and claudin-5 respectively. Taken together, our present study indicated that miR-18a increased the permeability of BTB via RUNX1 mediated down-regulation of tight junction related proteins ZO-1, occludin and claudin-5, which would attract more attention to miR-18a and RUNX1 as potential targets of drug delivery across BTB and provide novel strategies for glioma treatment.