Functional dissection and transport mechanism of magnesium in plants.

Magnesium (Mg) is the second most abundant cation in plants, and, as such, is involved in numerous physiological and biochemical processes, including photosynthesis, enzyme activation, and synthesis of nucleic acids and proteins. Due to its relatively small ionic radius and large hydrated radius, Mg binds weakly to soil and root surfaces, and thereby is easily leached from soil. Mg deficiency not only affects crop productivity and quality, but also contributes to numerous chronic human diseases. Therefore, Mg nutrition in plants is an important issue in nutrition and food security. To acquire and maintain high concentrations of Mg, plants have evolved highly-efficient systems for Mg uptake, storage and translocation. Advances in the understanding of fundamental principles of Mg nutrition and physiology are required in order to improve Mg nutrient management, Mg stress diagnosis, and genetic marker assisted breeding efforts. The aims of this review are to highlight physiological and molecular mechanisms underlying Mg biological functions and to summarize recent developments in the elucidation of Mg transport systems in plants.

A VIT-like transporter facilitates iron transport into nodule symbiosomes for nitrogen fixation in soybean.

Effective legume-rhizobia symbiosis depends on efficient nutrient exchange. Rhizobia need to synthesize iron-containing proteins for symbiotic nitrogen fixation (SNF) in nodules, which depends on host plant-mediated iron uptake into the symbiosome. We functionally investigated a pair of vacuolar iron transporter like (VTL) genes, GmVTL1a/b, in soybean (Glycine max) and evaluated their contributions to SNF, including investigations of gene expression patterns, subcellular localization, and mutant phenotypes. Though both GmVTL1a/b genes were specifically expressed in the fixation zone of the nodule, GmVTL1a was the lone member to be localized at the tonoplast of tobacco protoplasts, and shown to facilitate ferrous iron transport in yeast. GmVTL1a targets the symbiosome in infected cells, as verified by in situ immunostaining. Two vtl1 knockout mutants had lower iron concentrations in nodule cell sap and peribacteroid units than in wild-type plants, suggesting that GmVTL1 knockout inhibited iron import into symbiosomes. Furthermore, GmVTL1 knockout minimally affected soybean growth under nonsymbiotic conditions, but dramatically impaired nodule development and SNF activity under nitrogen-limited and rhizobia-inoculation conditions, which eventually led to growth retardation. Taken together, these results demonstrate that GmVTL1a is indispensable for SNF in nodules as a transporter of ferrous iron from the infected root cell cytosol to the symbiosome.

[A method of screening highly common neoantigens with immunogenicity in colorectal cancer based on public somatic mutation library].

Colorectal cancer (CRC) is a malignant cancer with high incidence and mortality in the world. Immunotherapy targeting neoantigens can induce durable tumor regression in cancer patients, but is almost limited to personalized precision therapy, due to the individual differences of unique neoantigens. With the discovery of many common oncogenic mutations, and such mutation-associated neoantigens could cover more patients, and hence are valuable in clinical field. However, whether the common neoantigens can be identified in CRC is unknown. Combining the somatic mutations data from 321 CRC patients with a filter standard and 7 predicted algorithms, we screened and obtained 25 HLA-A*1101-restricted common neoantigens with a high binding affinity (IC50<50 nmol/L) and presentation score (>0.90). Besides the positive epitope KRAS_G12V8-16, 11 out of 25 common neoantigens specifically induced in vitro pre- stimulated cytotoxic lymphocyte (CTL) to secrete interferon gamma (IFN-γ). Moreover, combining cell-sorting technology and single-cell RNA sequencing, the immune repertoire profiles of C1orf170_S418G413-421 and KRAS_G12V8-16-specific CTL were analyzed and validated. Their related T-cell receptor engineered T cell (TCR-T) cells could also recognize the neoantigens and secrete IFN-γ. Hence, we have established a method to screen for common neoantigens with immunogenicity in CRC based on the public somatic mutation library. It can provide essential peptide and TCR information for immunotherapies, such as peptides, dendritic cells (DC) vaccines, TCR-like antibodies, TCR-T, etc., for the CRC and other cancers, which has practical application value in the clinics.

Magnesium promotes root nodulation through facilitation of carbohydrate allocation in soybean.

Magnesium (Mg) is an essential element for the growth of both plants and bacteria. Low availability of Mg in agriculture can limit crop productivity and quality. In addition to direct effects on plant growth, limited Mg supply may also impact biological dinitrogen (N2 ) fixation in nodules formed from symbiotic interactions between legumes and rhizobial bacteria. To date, the physiological mechanisms involved in Mg-dependent nodulation remains largely unknown. The objectives of this work were to assess how Mg supply affects nodule growth and development in symbiotic systems, and to test if any observed changes in nodule and soybean are correlated with Mg supply. Here, we found that external Mg supply enhanced nodule growth under nitrogen (N) limited conditions, and subsequently improved N2 fixation and soybean growth. Mg supply altered neither nodule structure nor Mg homeostasis, but remarkably promoted nodule enlargement, resulting in an increase in the number of big nodules. In addition, high Mg supply decreased starch and sucrose accumulation in leaves, and increased their concentrations in roots, which consequently enhanced carbohydrate import into the rhizobia infection zone of nodules. In this study, Mg was shown to promote nodule growth in soybean. This Mg-promoted nodule growth is derived from Mg-facilitated alteration of carbohydrate partitioning and transport into nodules.

The role of G protein-coupled receptor kinases in the pathology of malignant tumors.

G protein-coupled receptor kinases (GRKs) constitute seven subtypes of serine/threonine protein kinases that specifically recognize and phosphorylate agonist-activated G protein-coupled receptors (GPCRs), thereby terminating the GPCRs-mediated signal transduction pathway. Recent research shows that GRKs also interact with non-GPCRs and participate in signal transduction in non-phosphorylated manner. Besides, GRKs activity can be regulated by multiple factors. Changes in GRKs expression have featured prominently in various tumor pathologies, and they are associated with angiogenesis, proliferation, migration, and invasion of malignant tumors. As a result, GRKs have been intensively studied as potential therapeutic targets. Herein, we review evolving understanding of the function of GRKs, the regulation of GRKs activity and the role of GRKs in human malignant tumor pathophysiology.

Emerging Roles of G Protein-Coupled Receptors in Hepatocellular Carcinoma.

Among a great variety of cell surface receptors, the largest superfamily is G protein-coupled receptors (GPCRs), also known as seven-transmembrane domain receptors. GPCRs can modulate diverse signal-transduction pathways through G protein-dependent or independent pathways which involve β-arrestins, G protein receptor kinases (GRKs), ion channels, or Src kinases under physiological and pathological conditions. Recent studies have revealed the crucial role of GPCRs in the tumorigenesis and the development of cancer metastasis. We will sum up the functions of GPCRs—particularly those coupled to chemokines, prostaglandin, lysophosphatidic acid, endothelin, catecholamine, and angiotensin—in the proliferation, invasion, metastasis, and angiogenesis of hepatoma cells and the development of hepatocellular carcinoma (HCC) in this review. We also highlight the potential avenues of GPCR-based therapeutics for HCC.

GATA3 mutations define a unique subtype of luminal-like breast cancer with improved survival.

BACKGROUND: The GATA3 gene (GATA-binding protein 3) is one of the most frequently mutated genes in breast cancer. The objective of the current study was to determine the clinicopathologic characteristics of patients with breast cancer harboring GATA3 mutations. METHODS: The authors examined the somatic mutation status of GATA3 and performed survival analysis in The Cancer Genome Atlas (TCGA) cohort (n=934) and the Fudan University Shanghai Cancer Center (FUSCC) cohort (n=308). Patient characteristics, including age; menopausal status; tumor laterality; tumor size; lymph node status; tumor grade; molecular subtypes; adjuvant radiotherapy, chemotherapy, and endocrine therapy; and prognosis, together with PIK3CA (phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit alpha) and TP53 (tumor protein p53) mutation status, were collected. RESULTS: GATA3 mutations were detected in 8.8% of patients (82 of 934 patients) in the TCGA cohort and 14.9% of patients (46 of 308 patients) in the FUSCC cohort. GATA3 mutations were found to be significantly associated with luminal-like breast cancer (P=.002 in the TCGA cohort and P<.001 in the FUSCC cohort), and were highly mutually exclusive to PIK3CA mutations (P=.001 in the TCGA cohort and P=.003 in the FUSCC cohort) and TP53 mutations (P<.001 in both cohorts). Furthermore, GATA3 mutations were correlated with improved overall survival in the entire population (P=.025 in the TCGA cohort and P = .043 in the FUSCC cohort) as well as in patients with luminal-like disease who received adjuvant endocrine therapy. CONCLUSIONS: GATA3 mutations mainly occur in patients with luminal-like breast cancer and have identifiable clinicopathologic and genetic characteristics, highlighting a subgroup of patients with breast cancer in whom limited therapy may be appropriate.

Elevated expression of Girdin in the nucleus indicates worse prognosis for patients with estrogen receptor-positive breast cancer.

BACKGROUND: Girdin was identified as a novel Akt substrate that contributes to a positive feedback loop between Girdin and Akt. Although several recent studies have demonstrated that Girdin is involved in tumor metastasis, the clinical implications of Girdin in breast cancer remain unclear. METHODS: To retrospectively evaluate the prognostic value of Girdin in breast cancer, we performed an immunohistochemistry screening for Girdin using tissue microarrays constructed from 250 patients who were histologically confirmed as having invasive ductal breast carcinoma at the Fudan University Shanghai Cancer Center. RESULTS: Our results demonstrated that the levels of Girdin in different subcellular distributions, including Girdin in the nucleus (GN) and the cytoplasm (GC) were each associated with the clinical parameters of breast cancer, including phospho-Akt (S473) [p = 0.014 for GN], phospho-Akt (T308) [p = 0.045 for GC], estrogen receptor (ER) [p = 0.012 for GN and p = 0.004 for GC], progesterone receptor (p = 0.028 for GC) and human epidermal growth factor receptor 2 status (p = 0.004 for GC). Moreover, we showed that elevated expression of GN indicated a worse disease-free survival (p = 0.032) and overall survival (p = 0.011) exclusively in the ER-positive breast cancer population. CONCLUSIONS: Cumulatively, our findings suggest that GN might serve as an important prognostic factor for ER-positive breast carcinoma.

Inhibition of ACAA1 Restrains Proliferation and Potentiates the Response to CDK4/6 Inhibitors in Triple-Negative Breast Cancer.

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer with unfavorable outcomes. Developing therapeutic targets for TNBC remains a challenge. Here, we identified that acetyl-CoA acyltransferase 1 (ACAA1) is highly expressed in the luminal androgen receptor (LAR) subtype of TNBC compared with adjacent normal tissues in our TNBC proteomics dataset. Inhibition of ACAA1 restrained TNBC proliferation and potentiated the response to the cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitor abemaciclib. Mechanistically, ACAA1 interacted with CDK4, and the inhibition of ACAA1 blocked RB transcriptional corepressor 1 (RB1) phosphorylation, resulting in G1-S cell-cycle arrest. Importantly, trimetazidine, a traditional drug for ischemic heart disease, caused a decrease in ACAA1 protein levels and enhanced the efficacy of abemaciclib in preclinical TNBC models. In conclusion, this study identifies that ACAA1 is a therapeutic target in TNBC and suggests the combination of trimetazidine and abemaciclib could be beneficial for ACAA1-high TNBCs. SIGNIFICANCE: ACAA1 is highly expressed in TNBC, serving as a potential therapeutic target in ACAA1-high tumors and a predictive biomarker of resistance to CDK4/6 inhibitors for RB1-proficient patients.

Tenofovir amibufenamide vs tenofovir alafenamide for treating chronic hepatitis B: A real-world study.

BACKGROUND: The efficacy and safety profile of tenofovir amibufenamide (TMF) in chronic hepatitis B (CHB) patients is not well-established. AIM: To compare the efficacy and safety of TMF and tenofovir alafenamide (TAF) over a 48-wk period in patients with CHB. METHODS: A total of 215 subjects meeting the inclusion criteria were enrolled and divided into two groups: TMF group (n = 106) and the TAF group (n = 109). The study included a comparison of virological response (VR): Undetectable hepatitis B virus DNA levels, alanine transaminase (ALT) normalization rates, renal function parameters, and blood lipid profiles. RESULTS: At 24 and 48 wk, VR rates for the TMF group were 53.57% and 78.57%, respectively, compared with 48.31% and 78.65% for the TAF group (P > 0.05). The VR rates were also similar in both groups among patients with low-level viremia, both hepatitis B e antigen (HBeAg)-positive and HBeAg-negative subgroups. The TMF cohort showed ALT normalization and renal safety profiles similar to the TAF group. There was a notable increase in total cholesterol levels in the TAF group (P = 0.045), which was not observed in the TMF group (P > 0.05). In patients with liver cirrhosis, both groups exhibited comparable VR and ALT normalization rates and renal safety profiles. However, the fibrosis 4 score at 48 wk showed a significant reduction in the TAF group as compared to the TMF group within the liver cirrhosis subgroup. CONCLUSION: Our study found TMF is as effective as TAF in treating CHB and has a comparable safety profile. However, TAF may be associated with worsening lipid profiles.

Carbon-nitrogen trading in symbiotic nodules depends on magnesium import.

Symbiotic nitrogen fixation provides large amounts of nitrogen for global agricultural systems with little environmental or economic costs. The basis of symbiosis is the nutrient exchange occurring between legumes and rhizobia, but key regulators controlling nutrient exchange are largely unknown. Here, we reveal that magnesium (Mg), an important nutrient factor that preferentially accumulates in inner cortical cells of soybean nodules, shows the most positive correlation with nodule carbon (C) import and nitrogen (N) export. We further identified a pair of Mg transporter genes, GmMGT4 and GmMGT5, that are specifically expressed in the nodule cortex, modulating both nodule Mg import and C-N transport processes. The GmMGT4&5-dependent Mg import activates the activity of a plasmodesmata-located ß-1,3-glucanase GmBG2 and consequently keeps plasmodesmata permeable for C-N transport in nodule inner cortical cells. Our studies discovered an important regulating pathway for host plants fine-tuning nodule C-N trading to achieve optimal growth, which may be helpful for optimizing nutrient management for soybean production.

Proteome-centric cross-omics characterization and integrated network analyses of triple-negative breast cancer.

We report a comprehensive proteomic study of a 90-case cohort of paired samples of triple-negative breast cancer (TNBC) in quantification, phosphorylation, and DNA-binding capacity. Four integrative subtypes (iP-1-4) are stratified on the basis of global proteome and phosphoproteome, each of which exhibits distinct molecular and pathway features. Scaffold and co-expression network analyses of three proteomic datasets, integrated with those from genome and transcriptome of the same cohort, reveal key pathways and master regulators that, characteristic of TNBC subtypes, play important regulatory roles within and between scaffold sub-structures and co-expression communities. We find that NAE1 is a potential drug target for subtype iP-1, and a series of key molecules in fatty acid metabolism, such as AKT1/FASN, are plausible targets for subtype iP-2. Libraries of proteins, pathways and networks of TNBC provide a valuable molecular infrastructure for further clinical exploration and in-depth studies of the molecular mechanisms of the disease.

ß-arrestin2 regulating ß2-adrenergic receptor signaling in hepatic stellate cells contributes to hepatocellular carcinoma progression.

Background: ß-arrestin2 and ß2-adrenergic receptor (ß2-AR) have important roles in malignant tumors, the present study aims to investigate the role of activated ß2-AR in hepatic stellate cells (HSCs) during hepatocellular carcinoma (HCC) progression and the regulatory effect of ß-arrestin2. Methods: Immunofluorescence and Western blot were used to detect the expression of ß-arrestin2 and ß2-AR in HSCs of liver tissues from human HCC samples and diethylnitrosamine (DEN)-induced HCC model mice. We next used ß-arrestin2-/- mice to demonstrate the regulatory role of ß-arrestin2 in DEN mice. The subsets of T cells were quantified by flow cytometry. MTT and wound healing assay were applied to detect the proliferation and migration of cells. Co-immunoprecipitation assay was used to detect the link of ß-arrestin2 and ß2-AR in HSCs. Effect of ß-arrestin2 overexpression on ß2-AR downstream signaling pathway was verified by Western blot. The secretion of CCL2 was detected by ELISA. Results: The expression of ß2-AR was significantly increased, while ß-arrestin2 was decreased in HSCs of HCC tissues. And ß-arrestin2 deficiency exacerbates DEN-induced HCC accompanied with increased ß2-AR expression. The results of flow cytometry showed that the percentage of activated T cells decreased gradually after DEN injection. ß-arrestin2 knockout down-regulated the ratio of activated T cells. In vitro, selective activation of ß2-AR in HSCs promoted the proliferation and migration of HCC cells. ß-arrestin2 overexpression enhanced co-immunoprecipitation of ß-arrestin2 and ß2-AR in activated HSCs, and decreased its downstream Akt phosphorylation. Akt inhibitor decreased secretion of CCL2 in activated HSCs. Conclusion: Our study demonstrated that ß2-AR activation in HSCs induces the proliferation and migration of HCC cells may be through Akt signaling, and this effect appears to be regulated by ß-arrestin2.

Microcliamte changes caused by black inter-row mulch decrease flavonoids concentrations in grapes and wines under semi-arid climate.

In this study, black geotextile inter-row mulch, a weed control practice, was applied under a semi-arid climate to attenuate solar reflection in 2015-2017, and it concurrently increased soil temperature and fruit-zone high temperature duration and decreased low temperature duration. Inter-row mulch decreased anthocyanins concentrations in grapes in 2015-2016, and consistently inhibited flavonols accumulation in 2015-2017. Correlation analysis between microclimate parameters and flavonoids concentrations reflected the importance of solar reflection, fruit-zone high and low temperature duration, heat accumulation and soil temperature to flavonoids accumulation. Basal leaf removal, a widely applied practice to increase fruit-zone light exposure, was applied to mulch-treated grapevines to investigate if increasing incident light could mitigate the impact of inter-row mulch on flavonoids, and it had limited influence on anthocyanins whereas compensated the loss of flavonols in grapes caused by inter-row mulch. Notably, inter-row mulch wines showed less red and more yellow color than controls because of lower anthocyanins concentrations.

Influence of attenuated reflected solar radiation from the vineyard floor on volatile compounds in Cabernet Sauvignon grapes and wines of the north foot of Mt. Tianshan.

In this study, fruit-zone microclimate was modified by three treatments, including inter-row mulch (M), the combination of leaf removal applied at the onset of veraison and inter-row mulch (MLR-BV), and the combination of leaf removal applied at complete veraison and inter-row mulch (MLR-EV), in a semi-arid climate in three consecutive years (2015-2017). M decreased fruit-zone reflected solar radiation from vineyard floor and low temperature (10-20 °C) duration, whereas it increased soil temperature and high temperature (> 30 °C) duration. MLR-BV and MLR-EV increased fruit-zone incident photosynthetically active radiation while decreased the duration of 20-25 °C compared to M. Notably, M significantly decreased grape total norisoprenoid concentrations in 2015-2017, and total terpenoid concentrations in 2015-2016. Applying leaf removal applied at the onset of veraison could compensate the decreases of total norisoprenoids and terpenoids caused by M when two treatments were applied together. Besides, M significantly increased grape total C6/C9 compound concentrations, besides, (Z)-3-hexen-1-ol concentrations were significantly higher in grapes of M than those of MLR-BV in 2015-2017. Light exposure and high temperature duration after veraison had strong positive correlations with total norisoprenoids and terpenoids, besides, low temperature duration was positively correlated with total norisoprenoids. In addition, light exposure after veraison had strong negative correlations with total C6/C9 compounds. With respect to the volatile compounds in wines, M significantly decreased the concentrations of isopentanol and ethyl acetate, and the concentrations of ethyl cinnamate, phenylacetaldehyde, phenylethyl alcohol and 3-methylthio-1-propanol were significantly lower in MLR-BV and MLR-EV than in M. The outcome of this study can assist winegrowers to properly adjust vineyard managements to optimize the concentrations of desired volatile compounds in grapes and wines.

Bioinformatics analysis of dysregulated microRNAs in exosomes from docetaxel-resistant and parental human breast cancer cells.

Background: Resistance to docetaxel is a major obstacle to effective treatment of breast cancer. Exosomal microRNAs (miRNAs) have recently been introduced in cell-to-cell transmission of chemoresistance between heterogeneous populations of tumor cells with diverse drug sensitivity. However, a systematic evaluation of the exosomal miRNA signature remains largely unclear. Method: miRNA expression profiles in exosomes from docetaxel-resistant (D/exo) and parental sensitive breast cancer cells (S/exo) were assessed using microarray. Bioinformatics analysis was performed to predict target genes of the dysregulated miRNAs and to uncover their potential roles in chemoresistance formation. Signaling pathways, gene ontology terms, transcription factors, protein-protein interactions, and hub genes were also constructed. Results: The selected exosomal miRNAs could modulate target genes responsible for MAPK, TGF-beta, Wnt, mTOR, and PI3K/Akt signaling pathways. Function enrichment analysis revealed the involvement of target genes in transcription regulation, protein phosphorylation, kinase activity, and protein binding. Enriched transcription factors including SP1, SP4, and EGR1 were obtained and a protein-protein interaction network was established. The hub genes for up-expressed and down-expressed exosomal miRNAs such as CCND1 and PTEN were identified. Conclusion: This bioinformatics study provides a comprehensive view of the function of dysregulated exosomal miRNAs, and may help us to understand exosome-mediated resistance transmission and overcome docetaxel resistance in future breast cancer therapy.

G protein-coupled receptor kinase 2 regulating ß2-adrenergic receptor signaling in M2-polarized macrophages contributes to hepatocellular carcinoma progression.

Background: ß2-adrenoceptors (ß2-ARs) are expressed on the surface of immune cells, including tumor-associated macrophages (TAMs). Previous studies have demonstrated that the expression of ß2-ARs in hepatocellular carcinoma (HCC) is significantly increased in vitro. However, the role of ß2-AR in M2-polarized macrophages remains unclear. G protein-coupled receptor kinase 2 (GRK2) can regulate G protein-coupled receptor (GPCR). Previous studies showed that down-regulation of GRK2 in HCC contributes the HCC progression, but it still remains unclear whether the regulation of ß2-AR in M2-polarized macrophages by GRK2 can promote HCC. Purpose: The present study was designed to investigate the role of activated ß2-AR in M2-polarized macrophages in the HCC progression and GRK2 regulatory effect, as well as the underlying mechanisms involved. Results: The results demonstrated that the M2-polarized macrophages were increased with HCC progression. In vitro, the activation of ß2-AR by terbutaline in M2-polarized macrophages elevated the proliferative, migratory and invasive attributes of HCC cells. Furthermore, GRK2 down-regulation in ß2-AR activated M2-polarized macrophages activated the downstream cyclic adenosine monophosphate (cAMP)/protein kinase A/cAMP-response element binding protein and cAMP/interleukin-6/signal transducer and the activator of transcription 3 signaling pathways, contributing to the secretion of tumor-associated cytokines, and thus resulting in the promotion of malignant biological behavior in HCC cells. Conclusion: These findings suggest that the regulation of ß2-AR occurs through the silencing of GRK2 in M2-polarized macrophages, which is conducive to HCC development, through its engagement in the activation of downstream signaling.

Influence of the harvest date on berry compositions and wine profiles of Vitis vinifera L. cv. 'Cabernet Sauvignon' under a semiarid continental climate over two consecutive years.

The ripeness of a grape is critical to berry composition and to the resultant wine. For wineries with a single cultivar occupying an extensive area, the total soluble solid of grapes can range from 22°Brix to 28°Brix. Accordingly, the influence of different harvest dates (ripeness) on berry compositions and on the resultant wine profile was investigated for Vitis vinifera L. cv. 'Cabernet Sauvignon.' Berry dehydration was observed as berry weight and juice yields decreased. Berry anthocyanins were concentrated and methylated anthocyanin levels fluctuated with increasing delays in harvesting. Hexanal and 2-hexenal levels in must decreased significantly as berries ripened. In the resultant wines, 2,3-butanediol levels increased. Wines harvested earlier were lighter, presented lower color intensity (CI) values and higher yellow% levels, and exhibited richer aroma profiles (compounds). Through a principal component analysis and discriminant analysis, the compounds characterizing each harvest date were identified.

Analysis of miRNA signature differentially expressed in exosomes from adriamycin-resistant and parental human breast cancer cells.

A major cause of failure in chemotherapy is drug resistance of cancer cells. Exosomes have been introduced to spread chemoresistance through delivering miRNAs. However, a systematic evaluation of the exosomal miRNA expression profiles responsible for chemoresistance is still lacking. In the present study, miRNA signature differentially expressed in exosomes derived from adriamycin-resistant (A/exo) and parental breast cancer cells (S/exo) were analyzed by microarray and the results were confirmed by PCR. A total of 309 miRNAs were increased and 66 miRNAs were decreased significantly in A/exo compared with S/exo. Specifically, 52 novel miRNAs with increased expression levels >16.0-fold in A/exo were identified. After prediction of target genes for 13 of 52 selected novel miRNAs, pathway analysis, gene ontology (GO) terms, and protein-protein interactions (PPIs) were constructed. The results implied that these selected exosomal miRNAs inhibited target genes involved in transcriptional misregulation in cancer, MAPK, and Wnt signaling pathways. Functional enrichment analysis demonstrated that the target genes were mainly responsible for protein phosphorylation, transcription regulation, molecular binding, and kinase activity. In summary, the current bioinformatics study of exosomal miRNAs may offer a new understanding into mechanisms of chemoresistance, which is helpful to find potential exosomal miRNAs to overcome drug insensitivity in future breast cancer treatment.

d Rhamnose ß-hederin reverses chemoresistance of breast cancer cells by regulating exosome-mediated resistance transmission.

d Rhamnose ß-hederin (DRß-H), an active component extracted from the traditional Chinese medicinal plant Clematis ganpiniana, has been reported to be effective against breast cancer. Recent studies have also indicated that the isolated exosomes (D/exo) from docetaxel-resistant breast cancer cells MCF-7 (MCF-7/Doc) were associated with resistance transmission by delivering genetic cargo. However, the relevance of D/exo during DRß-H exposure remains largely unclear. In the present work, exosomes were characterized by morphology and size distribution. We reinforced the significant role of D/exo in spreading chemoresistance from MCF-7/Doc to recipient sensitive cells after absorption and internalization. DRß-H could reduce the formation and release of D/exo. Next, we demonstrated that DRß-H was able to reverse docetaxel resistance and that D/exo was responsible for DRß-H-mediated resistance reversal. We also found that DRß-H could decrease the expressions of several most abundant miRNAs (miR-16, miR-23a, miR-24, miR-26a, and miR-27a) transported by D/exo. Target gene prediction and pathway analysis showed the involvement of these selected miRNAs in pathways related to treatment failure. Our results suggested that DRß-H could reduce D/exo secretion from MCF-7/Doc cells and induce the reduction in resistance transmission via D/exo.