DDX17-regulated alternative splicing that produced an oncogenic isoform of PXN-AS1 to promote HCC metastasis.

BACKGROUND AND AIMS: The mechanism underlying HCC metastasis remains unclear, many oncogenes are known to regulate this process. However, the role of alternative splicing (AS) in pro-metastatic HCC is poorly understood. APPROACH AND RESULTS: By performing RNA sequencing on nine pairs of primary HCC tissues with extrahepatic metastasis (EHMH) and nine pairs of metastasis-free HCC (MFH) tissues, we depicted the AS landscape in HCC and found a higher frequency of AS events in EHMH compared with MFH. Moreover, 28 differentially expressed splicing regulators were identified in EHMH compared with MFH. Among these, DEAD-box RNA helicase 17 (DDX17) was significantly up-regulated in EHMH and was strongly associated with patient outcome. Functional studies indicated that DDX17 knockout inhibited the degradation of the extracellular matrix, and diminished the invasive ability of HCC cells. A significant reduction in lung metastasis induced by DDX17 deficiency was also demonstrated in a diethylnitrosamine-induced DDX17HKO mouse model. Mechanistically, high DDX17 induced intron 3 retention of PXN-AS1 and produced a transcript (termed PXN-AS1-IR3). The transcript PXN-AS1-IR3 acted as an important promoter of HCC metastasis by inducing MYC transcription activation via recruiting the complex of testis expressed 10 and p300 to the MYC enhancer region, which led to transcriptional activation of several metastasis-associated downstream genes. Finally, the PXN-AS1-IR3 level was significantly higher in serum and HCC tissues with extrahepatic metastasis. CONCLUSIONS: DDX17 and PXN-AS1-IR3 act as important metastatic promoters by modulating MYC signaling, suggesting that DDX17 and PXN-AS1-IR3 may be potential prognostic markers for metastatic HCC.

Dicoumarol, an NQO1 inhibitor, blocks cccDNA transcription by promoting degradation of HBx.

BACKGROUND & AIMS: Current antiviral therapies help keep HBV under control, but they are not curative, as they are unable to eliminate the intracellular viral replication intermediate termed covalently closed circular DNA (cccDNA). Therefore, there remains an urgent need to develop strategies to cure CHB. Functional silencing of cccDNA is a crucial curative strategy that may be achieved by targeting the viral protein HBx. METHODS: We screened 2,000 small-molecule compounds for their ability to inhibit HiBiT-tagged HBx (HiBiT-HBx) expression by using a HiBiT lytic detection system. The antiviral activity of a candidate compound and underlying mechanism of its effect on cccDNA transcription were evaluated in HBV-infected cells and a humanised liver mouse model. RESULTS: Dicoumarol, an inhibitor of NAD(P)H:quinone oxidoreductase 1 (NQO1), significantly reduced HBx expression. Moreover, dicoumarol showed potent antiviral activity against HBV RNAs, HBV DNA, HBsAg and HBc protein in HBV-infected cells and a humanised liver mouse model. Mechanistic studies demonstrated that endogenous NQO1 binds to and protects HBx protein from 20S proteasome-mediated degradation. NQO1 knockdown or dicoumarol treatment significantly reduced the recruitment of HBx to cccDNA and inhibited the transcriptional activity of cccDNA, which was associated with the establishment of a repressive chromatin state. The absence of HBx markedly blocked the antiviral effect induced by NQO1 knockdown or dicoumarol treatment in HBV-infected cells. CONCLUSIONS: Herein, we report on a novel small molecule that targets HBx to combat chronic HBV infection; we also reveal that NQO1 has a role in HBV replication through the regulation of HBx protein stability. LAY SUMMARY: Current antiviral therapies for hepatitis B are not curative because of their inability to eliminate covalently closed circular DNA (cccDNA), which persists in the nuclei of infected cells. HBV X (HBx) protein has an important role in regulating cccDNA transcription. Thus, targeting HBx to silence cccDNA transcription could be an important curative strategy. We identified that the small molecule dicoumarol could block cccDNA transcription by promoting HBx degradation; this is a promising therapeutic strategy for the treatment of chronic hepatitis B.

SIRT7 restricts HBV transcription and replication through catalyzing desuccinylation of histone H3 associated with cccDNA minichromosome.

Chronic hepatitis B virus (HBV) infection is a significant public health burden worldwide. HBV covalently closed circular DNA (cccDNA) organized as a minichromosome in nucleus is responsible for viral persistence and is the key obstacle for a cure of chronic hepatitis B (CHB). Recent studies suggest cccDNA transcription is epigenetically regulated by histone modifications, especially histone acetylation and methylation. In the present study, we identified transcriptionally active histone succinylation (H3K122succ) as a new histone modification on cccDNA minichromosome by using cccDNA ChIP-Seq approach. Silent mating type information regulation 2 homolog 7 (SIRT7), as an NAD+-dependent histone desuccinylase, could bind to cccDNA through interaction with HBV core protein where it catalyzed histone 3 lysine 122 (H3K122) desuccinylation. Moreover, SIRT7 acts cooperatively with histone methyltransferase, suppressor of variegation 3-9 homolog 1 (SUV39H1) and SET domain containing 2 (SETD2) to induce silencing of HBV transcription through modulation of chromatin structure. Our data improved the understanding of histone modifications of the cccDNA minichromosome, thus transcriptional silencing of cccDNA may represent a novel antiviral strategy for the prevention or treatment of HBV infection.

A Functional Variant in Ubiquitin Conjugating Enzyme E2 L3 Contributes to Hepatitis B Virus Infection and Maintains Covalently Closed Circular DNA Stability by Inducing Degradation of Apolipoprotein B mRNA Editing Enzyme Catalytic Subunit 3A.

Hepatitis B virus (HBV) infection is a common infectious disease, in which nuclear covalently closed circular DNA (cccDNA) plays a key role in viral persistence, viral reactivation after treatment withdrawal, and drug resistance. A recent genome-wide association study has identified that the ubiquitin conjugating enzyme E2 L3 (UBE2L3) gene is associated with increased susceptibility to chronic HBV (CHB) infection in adults. However, the association between UBE2L3 and children with CHB and the underlying mechanism remain unclear. In this study, we performed two-stage case-control studies including adults and independent children in the Chinese Han population. The rs59391722 allele in the promoter of the UBE2L3 gene was significantly associated with HBV infection in both adults and children, and it increased the promoter activity of UBE2L3. Serum UBE2L3 protein levels were positively correlated with HBV viral load and hepatitis B e antigen (HBeAg) levels in children with CHB. In an HBV infection cell model, UBE2L3 knockdown significantly reduced total HBV RNAs, 3.5-kb RNA, as well as cccDNA in HBV-infected HepG2-Na+ /taurocholate cotransporting polypeptide cells and human primary hepatocytes. A mechanistic study found that UBE2L3 maintained cccDNA stability by inducing proteasome-dependent degradation of apolipoprotein B mRNA editing enzyme catalytic subunit 3A, which is responsible for the degradation of HBV cccDNA. Moreover, interferon-α (IFN-α) treatment markedly decreased UBE2L3 expression, while UBE2L3 silencing reinforced the antiviral activity of IFN-α on HBV RNAs, cccDNA, and DNA. rs59391722 in UBE2L3 was correlated with HBV DNA suppression and HBeAg loss in response to IFN-α treatment of children with CHB. Conclusion: These findings highlight a host gene, UBE2L3, contributing to the susceptibility to persistent HBV infection; UBE2L3 may be involved in IFN-mediated viral suppression and serve as a potential target in the prevention and treatment of HBV infection.

Association between the insulin-like growth factor 1 gene rs2195239 and rs2162679 polymorphisms and cancer risk: a meta-analysis.

BACKGROUND: Many epidemiological studies have suggested that insulin-like growth factor1 (IGF1) gene single-nucleotide polymorphisms (SNPs) may be associated with cancer risk. Among several commonly studied polymorphisms in IGF1 gene, rs2195239 and rs2162679 attracted many attentions. So we perform a meta-analysis to determine potential associations between IGF1 rs2195239 and rs2162679 polymorphisms and cancer risk. METHODS: We retrieved relevant articles from the PubMed, Embase, and Web of Science databases up to April 30, 2018. Ultimately, thirteen studies were included in the present meta-analysis, which involved 12,515 cases and 19,651 controls. The odd ratios (ORs) and their 95% confidence intervals (CIs) were pooled to estimate the strength of the associations. RESULTS: rs2195239 reduces the overall cancer risk in homozygote model, as well as reducing cancer risk in Asian populations in allele, homozygote, and recessive models. No significant relationship was found between rs2195239 and breast or pancreatic cancer risk. rs2162679 reduces the overall cancer risk in allele, homozygote, dominant, and recessive models, as well as reducing cancer risk in Asian populations in allele, homozygote, and recessive models. CONCLUSIONS: IGF1 rs2195239 and rs2162679 were associated with overall cancer risk based on present studies.

SIRT3 restricts hepatitis B virus transcription and replication through epigenetic regulation of covalently closed circular DNA involving suppressor of variegation 3-9 homolog 1 and SET domain containing 1A histone methyltransferases.

Hepatitis B virus (HBV) infection remains a major health problem worldwide. Maintenance of the covalently closed circular DNA (cccDNA), which serves as a template for HBV RNA transcription, is responsible for the failure of eradicating chronic HBV during current antiviral therapy. cccDNA is assembled with cellular histone proteins into chromatin, but little is known about the regulation of HBV chromatin by histone posttranslational modifications. In this study, we identified silent mating type information regulation 2 homolog 3 (SIRT3) as a host factor restricting HBV transcription and replication by screening seven members of the sirtuin family, which is the class III histone deacetylase. Ectopic SIRT3 expression significantly reduced total HBV RNAs, 3.5-kb RNA, as well as replicative intermediate DNA in HBV-infected HepG2-Na+ /taurocholate cotransporting polypeptide cells and primary human hepatocytes. In contrast, gene silencing of SIRT3 promoted HBV transcription and replication. A mechanistic study found that nuclear SIRT3 was recruited to the HBV cccDNA, where it deacetylated histone 3 lysine 9. Importantly, occupancy of SIRT3 on cccDNA could increase the recruitment of histone methyltransferase suppressor of variegation 3-9 homolog 1 to cccDNA and decrease recruitment of SET domain containing 1A, leading to a marked increase of trimethyl-histone H3 (Lys9) and a decrease of trimethyl-histone H3 (Lys4) on cccDNA. Moreover, SIRT3-mediated HBV cccDNA transcriptional repression involved decreased binding of host RNA polymerase II and transcription factor Yin Yang 1 to cccDNA. Finally, hepatitis B viral X protein could relieve SIRT3-mediated cccDNA transcriptional repression by inhibiting both SIRT3 expression and its recruitment to cccDNA. CONCLUSION: SIRT3 is a host factor epigenetically restricting HBV cccDNA transcription by acting cooperatively with histone methyltransferase; these data provide a rationale for the use of SIRT3 activators in the prevention or treatment of HBV infection. (Hepatology 2018).

The association between hypoxia inducible factor 1 subunit alpha gene rs2057482 polymorphism and cancer risk: a meta-analysis.

BACKGROUND: The rs2057482 polymorphism in the hypoxia inducible factor 1 subunit alpha (HIF1A) gene has been reported to be associated with a risk of several types of cancer, but this association has not yet been definitively confirmed. We performed this meta-analysis to determine whether rs2057482 is associated with overall cancer risk. METHODS: The PubMed, Embase, and Web of Science databases were searched for the potential studies about the association between the rs2057482 and cancer risk. The data of genotype frequencies in cases with cancer and controls were extracted from the selected studies. Odds ratios (ORs) and the corresponding 95% confidence intervals (CIs) were calculated to determine the strength of the associations. RESULTS: The meta-analysis showed an association between the rs2057482 polymorphism and overall cancer risk. However, a stratified analysis of ethnicity did not show any significant association between rs2057482 and cancer risk in the Asian population. CONCLUSIONS: The rs2057482 polymorphism was associated with decreased overall cancer risk, based on the currently available studies. However, this conclusion needs verification by further well-designed epidemiology studies that examine different cancer types and more subjects.

The association between IGF1 gene rs1520220 polymorphism and cancer susceptibility: a meta-analysis based on 12,884 cases and 58,304 controls.

BACKGROUND: The rs1520220 polymorphism in the insulin-like growth factor 1 (IGF1) gene has been reported to affect cancer susceptibly in several studies. However, the results of the relevant studies are inconsistent. We conduct a current meta-analysis to investigate the association between rs1520220 and cancer susceptibly. METHODS: Three databases (PubMed, Embase, and Web of Science) were searched for studies regarding the relationship between rs1520220 and cancer susceptibly. Odds ratios (ORs) and the related 95% confidence intervals (CIs) were employed to assess the strength of the associations. A stratified analysis was performed according to cancer type, ethnicity, and quality score, and when results were obtained from no fewer than two studies, these results were pooled. RESULTS: There was no positive association between rs1520220 and overall cancer risk. However, the analysis stratified by ethnicity revealed that rs1520220 significantly increased cancer susceptibility in Asian populations (allele model OR = 1.10, 95%Cl = 1.00-1.21, p = 0.040; homozygote model OR = 1.22, 95%Cl = 1.01-1.47, p = 0.040; dominant model OR = 1.19, 95%Cl = 1.01-1.39, p = 0.033). No significantly association was detected in Caucasian populations. The analysis stratified by cancer type suggested that rs1520220 was not associated with susceptibility to breast cancer. CONCLUSIONS: The results of our meta-analysis demonstrate that the role of IGF1 rs1520220 in cancer susceptibility varies by ethnicity and cancer type and that rs1520220 increases cancer susceptibility in Asian populations.

Exosomes decrease sensitivity of breast cancer cells to adriamycin by delivering microRNAs.

While adriamycin (adr) offers improvement in survival for breast cancer (BCa) patients, unfortunately, drug resistance is almost inevitable. Mounting evidence suggests that exosomes act as a vehicle for genetic cargo and constantly shuttle biologically active molecules including microRNAs (miRNAs) between heterogeneous populations of tumor cells, engendering a resistance-promoting niche for cancer progression. Our recent study showed that exosomes from docetaxel-resistance BCa cells could modulate chemosensitivity by delivering miRNAs. Herein, we expand on our previous finding and explore the relevance of exosome-mediated miRNA delivery in resistance transmission of adr-resistant BCa sublines. We now demonstrated the selective packing of miRNAs within the exosomes (A/exo) derived from adr-resistant BCa cells. The highly expressed miRNAs in A/exo were significantly increased in recipient fluorescent sensitive cells (GFP-S) after A/exo incorporation. Gene ontology analysis of predicted targets showed that the top 30 most abundant miRNAs in A/exo were involved in crucial biological processes. Moreover, A/exo not only loaded miRNAs for its production and release but also carried miRNAs associated with Wnt signaling pathway. Furthermore, A/exo co-culture assays indicated that miRNA-containing A/exo was able to increase the overall resistance of GFP-S to adr exposure and regulate gene levels in GFP-S. Our results reinforce our earlier reports that adr-resistant BCa cells could manipulate a more deleterious microenvironment and transmit resistance capacity through altering gene expressions in sensitive cells by transferring specific miRNAs contained within exosomes.

Exosomes from adriamycin-resistant breast cancer cells transmit drug resistance partly by delivering miR-222.

Breast cancer (BCa) is one of the major deadly cancers in women. However, treatment of BCa is still hindered by the acquired-drug resistance. It is increasingly reported that exosomes take part in the development, metastasis, and drug resistance of BCa. However, the specific role of exosomes in drug resistance of BCa is poorly understood. In this study, we investigate whether exosomes transmit drug resistance through delivering miR-222. We established an adriamycin-resistant variant of Michigan Cancer Foundation-7 (MCF-7) breast cancer cell line (MCF-7/Adr) from a drug-sensitive variant (MCF-7/S). Exosomes were isolated from cell supernatant by ultracentrifugation. Cell viability was assessed by MTT assay and apoptosis assay. Individual miR-222 molecules in BCa cells were detected by fluorescence in situ hybridization (FISH). Then, FISH was combined with locked nucleic acid probes and enzyme-labeled fluorescence (LNA-ELF-FISH). Individual miR-222 could be detected as bright photostable fluorescent spots and then the quantity of miR-222 per cell could be counted. Stained exosomes were taken in by the receipt cells. MCF-7/S acquired drug resistance after co-culture with exosomes from MCF-7/Adr (A/exo) but did not after co-culture with exosomes from MCF-7/S (S/exo). The quantity of miR-222 in A/exo-treated MCF-7/S was significantly greater than in S/exo-treated MCF-7/S. MCF-7/S transfected with miR-222 mimics acquired adriamycin resistance while MCF-7/S transfected with miR-222 inhibitors lost resistance. In conclusion, exosomes are effective in transmitting drug resistance and the delivery of miR-222 via exosomes may be a mechanism.

Exosomes in development, metastasis and drug resistance of breast cancer.

Transport through the cell membrane can be divided into active, passive and vesicular types (exosomes). Exosomes are nano-sized vesicles released by a variety of cells. Emerging evidence shows that exosomes play a critical role in cancers. Exosomes mediate communication between stroma and cancer cells through the transfer of nucleic acid and proteins. It is demonstrated that the contents and the quantity of exosomes will change after occurrence of cancers. Over the last decade, growing attention has been paid to the role of exosomes in the development of breast cancer, the most life-threatening cancer in women. Breast cancer could induce salivary glands to secret specific exosomes, which could be used as biomarkers in the diagnosis of early breast cancer. Exosome-delivered nucleic acid and proteins partly facilitate the tumorigenesis, metastasis and resistance of breast cancer. Exosomes could also transmit anti-cancer drugs outside breast cancer cells, therefore leading to drug resistance. However, exosomes are effective tools for transportation of anti-cancer drugs with lower immunogenicity and toxicity. This is a promising way to establish a drug delivery system.

Sirtuin 1 regulates hepatitis B virus transcription and replication by targeting transcription factor AP-1.

Chronic hepatitis B virus (HBV) infection is a major risk factor for liver cirrhosis and hepatocellular carcinoma. Nevertheless, the molecular mechanism of HBV replication remains elusive. SIRT1 is a class III histone deacetylase that is a structure component of the HBV cccDNA minichromosome. In this study, we found by using microarray-based gene expression profiling analysis that SIRT1 was upregulated in HBV-expressing cells. Gene silencing of SIRT1 significantly inhibited HBV DNA replicative intermediates, 3.5-kb mRNA, and core protein levels. In contrast, the overexpression of SIRT1 augmented HBV replication. Furthermore, SIRT1 enhanced the activity of HBV core promoter by targeting transcription factor AP-1. The c-Jun subunit of AP-1 was bound to the HBV core promoter region, as demonstrated by using a chromatin immunoprecipitation assay. Mutation of AP-1 binding site or knockdown of AP-1 abolished the effect of SIRT1 on HBV replication. Finally, SIRT1 inhibitor sirtinol also suppressed the HBV DNA replicative intermediate, as well as 3.5-kb mRNA. Our study identified a novel host factor, SIRT1, which may facilitate HBV replication in hepatocytes. These data suggest a rationale for the use of SIRT1 inhibitor in the treatment of HBV infection.

Role of miR-155 in drug resistance of breast cancer.

MicroRNAs (miRNAs) are small noncoding RNAs that regulate gene expressions at posttranscriptional level. Growing evidence points to their significant role in the acquisition of drug resistance in cancers. Studies show that miRNAs are often aberrantly expressed in human cancer cells which are associated with tumorigenesis, metastasis, invasiveness, and drug resistance. Breast cancer is the leading cause of cancer-induced death in women. Over the last decades, increasing attention has been paid to the effects of miRNAs on the development of breast cancer drug resistance. Among them, miR-155 takes part in a sequence of bioprocesses that contribute to the development of such drug resistance, including repression of FOXO3a, enhancement of epithelial-to-mesenchymal transition (EMT) and mitogen-activated protein kinase (MAPK) signaling, reduction of RhoA, and affecting the length of telomeres. In this review, we discuss the role of miR-155 in the acquisition of breast cancer drug resistance. This will provide a new way in antiresistance treatment of drug-resistant breast cancer.

MicroRNA-452 contributes to the docetaxel resistance of breast cancer cells.

MicroRNA-452 (miRNA-452) was overexpressed in docetaxel-resistant human breast cancer MCF-7 cells (MCF-7/DOC). However, its role in modulating the sensitivity of breast cancer cells to docetaxel (DOC) remains unclear. The aim of this study is to investigate the role of miRNA-452 in the sensitivity of breast cancer cells to DOC.Real-time quantitative PCR (RT-qPCR) were used to identify the differential expression of miRNA-452 between MCF-7/DOC and MCF-7 cells. MiRNA-452 mimic was transfected into MCF-7 cells and miRNA-452 inhibitor was transfected into MCF-7/DOC cells. The role of miRNA-452 in these transfected cells was evaluated using RT-qPCR, MTT assay, and flow cytometry assay. The relationship of miRNA-452 and its predictive target gene "anaphase-promoting complex 4" (APC4) was analyzed by RT-qPCR and Western blot.MiRNA-452 showed significantly higher expression (78.9-folds) in MCF-7/DOC cells compared to parental MCF-7 cells. The expression of miRNA-452 in the mimic transfected MCF-7 cells was upregulated 212.2-folds (P < 0.05) compared to its negative control (NC), and the half maximal inhibitory concentration (IC50) value of DOC (1.98 ± 0.15 µM) was significantly higher than that in its NC (0.85 ± 0.08 µM, P < 0.05) or blank control (1.01 ± 0.19 µM, P < 0.05). Furthermore, its apoptotic rate (6.3 ± 1.3 %) was distinctly decreased compared with that in its NC (23.8 ± 6.6 %, P < 0.05) or blank control (18.6 ± 4.7 %, P < 0.05). In contrast, the expression of miRNA-452 in the inhibitor-transfected MCF-7/DOC cells was downregulated 0.58-fold (P < 0.05) compared to its NC, the IC50 value of DOC (44.5 ± 3.2 µM) was significantly lower than that in its NC (107.3 ± 6.63 µM, P < 0.05) or blank control (102.22 ± 11.34 µM, P < 0.05), and the apoptotic rate (45.5 ± 10.8 %) was distinctly increased compared with its NC (9.9 ± 2.2 %, P < 0.05) and blank control (9.4 ± 2.5 %, P < 0.05). Further, there was an inverse association between miRNA-452 and APC4 expression in breast cancer cells in vitro.Dysregulation of miRNA-452 involved in the DOC resistance formation of breast cancer cells may be, in part, via targeting APC4.

MicroRNAs delivered by extracellular vesicles: an emerging resistance mechanism for breast cancer.

Resistance to chemotherapy and endocrine therapy as well as targeted drugs is a major problem in treatment of breast cancer. Over the last decades, emerging studies have revealed that extracellular vesicles, which are chronically released by breast cancer cells and surrounding stromal cells, influence the action of most commonly used therapeutics. Such modulatory effects have been related to the transport of biologically active molecules including proteins and functional microRNAs. In this review, we highlight recent studies regarding extracellular vesicle-mediated microRNA delivery in formatting drug resistance. We also suggest the use of extracellular vesicles as a promising method in antiresistance treatment.

Exosomes from docetaxel-resistant breast cancer cells alter chemosensitivity by delivering microRNAs.

Breast cancer (BCa) remains chemo-unresponsive by inevitable progression of resistance to first-line treatment with docetaxel (doc). Emerging studies indicate that exosomes act as mediators of intercellular communication between heterogeneous populations of tumor cells, engendering a transmitted drug resistance for cancer development. Such modulatory effects have been related to the constant shuttle of biologically active molecules including microRNAs (miRNAs). Here, we aimed to investigate the relevance of exosome-mediated miRNA delivery in resistance transmission of BCa subpopulations. Using microarray and polymerase chain reaction, we found that exosomes from doc-resistant BCa cells (D/exo) loaded cellular miRNAs. Following D/exo transfer to the fluorescent sensitive cells (GFP-S), some miRNAs were significantly increased in recipient GFP-S. Target gene prediction and pathway analysis revealed the involvement of the top 20 most abundant miRNAs of D/exo in pathways implicated in therapy failure. Coculture assays showed that miRNA-containing D/exo increased the overall resistance of GFP-S to doc exposure. Moreover, D/exo was able to alter gene expression in GFP-S. Our results open up an intriguing possibility that drug-resistant BCa cells may spread chemoresistance to sensitive ones by releasing exosomes and that the effects could be partly attributed to the intercellular transfer of specific miRNAs.

Exosomes mediate drug resistance transfer in MCF-7 breast cancer cells and a probable mechanism is delivery of P-glycoprotein.

Acquired drug resistance is a major obstacle to chemotherapy of cancers. In this study, we aim to investigate the role of exosomes in drug-resistance transfer between breast cancer cells and detect the probable mechanism. A docetaxel-resistant variant of MCF-7 cell line (MCF-7/DOC) was established and then compared with the drug-sensitive variant (MCF-7/S). Exosomes were expelled from the cell supernatant using ultracentrifugation. Drug resistance was assessed by apoptosis assay and MTT examination. Expressions of P-glycoprotein (P-gp) were analyzed by flow cytometry. Stained exosomes were absorbed by receipt cells. MCF-7/S in the presence of exosomes extracted from the supernatant of MCF-7/DOC (DOC/exo) acquired drug resistance, while MCF-7/S exposed to their own exosomes (S/exo) did not. P-gp expression patterns of exosomes were similar as the originated cells. P-gp expression of MCF-7/S increased after incubation with DOC/exo and was affected by the amount of exosomes. Exosomes are effective in transferring drug resistance as well as P-gp from drug-resistant breast cancer cells to sensitive ones. The delivery of P-gp via exosomes may be a mechanism of exosome-mediated drug resistance transfer.

Meta-analysis: diagnostic accuracy of anti-cyclic citrullinated peptide 2 antibody and anti-cyclic citrullinated peptide 3 antibody in rheumatoid arthritis.

The aim of this work was to assess the diagnostic value of anti-CCP-3 and anti-CCP-2 for the diagnosis of rheumatoid arthritis (RA) and determine whether anti-CCP-3 more accurately identifies patients with rheumatoid arthritis than anti-CCP-2. PubMed and CNKI databases were searched for studies published in English and Chinese that examined the use of anti-CCP-3 and anti-CCP-2 in the diagnosis of known or suspected rheumatoid arthritis from January 2006 to July 2013. Seventeen included studies of methodological quality were rated by using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS) tools A random-effects method was used to summarize sensitivities, specificities, positive and negative likelihood ratio (LR+ and LR-, respectively), and diagnostic odds ratio from 17 studies. The pooled sensitivity, specificity, LR+, LR- and diagnostic odds ratio for anti-CCP-3 were 0.737 (95% CI, 0.717-0.757), 0.933 (95% CI, 0.924-0.942), 11.096 (95% CI, 8.876-13.870), 0.274 (95% CI, 0.231-0.326), and 42.908 (95% CI, 33.828-54.426), respectively. For anti-CCP-2, the values were 0.719 (95% CI, 0.699-0.739), 0.960 (95% CI, 0.953-0.966), 17.485 (95% CI, 11.960-25.562), 0.294 (95% CI, 0.258-0.335) and 63.458 (95% CI, 44.214-91.078), respectively. With high specificity and moderate sensitivity, anti-CCP-2 and anti-CCP-3 played an important role in confirming the diagnosis of RA. Anti-CCP-3 did not have better diagnostic performances than anti-CCP-2, but anti-CCP-2 had evident heterogeneity compared to anti-CCP-3, especially in American patients.

The accuracy of the anti-mitochondrial antibody and the M2 subtype test for diagnosis of primary biliary cirrhosis: a meta-analysis.

The aim of this study was to evaluate the diagnostic value of anti-mitochondrial antibodies (AMAs) and/or the M2 subtype (AMA-M2) in patients with primary biliary cirrhosis (PBC). AMA/AMA-M2 data were obtained by searching electronic databases. Studies showing AMA/AMA-M2 results in patients with PBC and control groups with other liver diseases or healthy livers were included. The quality of the involved studies was assessed using the QUADAS tool. The pooled sensitivity and specificity were calculated, and stratified analysis was performed according to possible heterogeneity sources. The pooled AMA (all methods) sensitivity and specificity were 84.5% (95% confidence interval (CI) 83.3%-85.6%) and 97.8% (95% CI 97.6%-98.0%), respectively. The positive and negative likelihood ratios were 25.201 (95% CI 17.583-36.118) and 0.162 (95% CI 0.131-0.199), respectively. The current evidence suggests that AMA and AMA-M2 show favorable accuracy for the diagnosis of PBC with high specificity and sensitivity. AMA is a better and more comprehensive marker than AMA-M2. The accuracy established in this meta-analysis is based on clinical studies using patient cohorts from different ethnicities.

miR-221/222: promising biomarkers for breast cancer.

MicroRNAs (miRNAs) are small noncoding RNAs of 19-25 nt that can regulate gene expression at a posttranscriptional level. Increasing evidence indicates that miRNAs participate in almost every step of cellular processes and are often aberrantly expressed in human cancer. miR-221 and miR-222 are two highly homologous miRNAs that always act as a gene cluster (miR-221/222) in cellular regulation and have extensively been studied in cancer network. Here, we review the role of miR-221/222 in breast cancer (BCa) development and progression: regulating proliferative signaling pathways, altering telomere and telomerase activity, avoiding cell death from tumor suppressors, autophagy and apoptosis, monitoring angiogenesis, supporting epithelial-mesenchymal transition, and even controlling cell-specific function within microenvironment. We consider that miR-221/222 act as promising biomarkers for BCa and they would offer a new way in molecular targeting cancer treatment.