Analysis of risk factors for systemic inflammatory response syndrome in patients after transcatheter aortic valve replacement.

OBJECTIVE: Our aim was to determine the risk factors of postoperative systemic inflammatory response syndrome (SIRS) in patients with transcatheter aortic valve replacement (TAVR), identify those with a high risk of SIRS, and help reduce SIRS occurrence. METHODS: A retrospective cohort study was conducted to collect the clinical data of patients who underwent TAVR from January 2014 to December 2019 at a tertiary hospital in Zhejiang Province. The study included 156 men and 94 women. Patients were divided into SIRS and non-SIRS groups. The pre-, intra-, and postoperative indices of the two groups were recorded. The data of the two groups were compared, and univariate analysis was performed. All statistically significant factors were assessed using binary logistic regression analysis to clarify the risk factors of SIRS after TAVR. RESULTS: Overall, 30 patients developed SIRS after TAVR, with an incidence rate of 12%, an odds ratio (OR) of 0.571, and a 95% confidence interval (CI) of 0.469-0.694 (p = 0.000). There was a significant correlation between SIRS and glucose (OR: 0.823, 95% CI: 0.678-1.000, p = 0.049), albumin (OR: 0.938, 95% CI: 0.881-0.998, p = 0.044), brain natriuretic peptide (OR: 1.000, 95% CI: 1.000-1.000, p = 0.010), sex (OR: 0.412, 95% CI: 0.190-0.892, p = 0.025), and history of hypertension (OR: 0.375, 95% CI: 0.169-0.819, p = 0.014). Multivariate regression analysis demonstrated that age (OR: 1.190, 95%CI: 1.073-1.319, p = 0.001) and body mass index (BMI; OR: 0.559, 95% CI: 0.447-0.698, p = 0.000) were independent risk factors for postoperative SIRS in patients with TAVR. CONCLUSION: The incidence of SIRS after TAVR was 12%. There was a significant correlation between SIRS and albumin, glucose, and hypertension. The independent risk factors for SIRS after TAVR were age and BMI.

Interindividual epigenetic variation in ABCB1 promoter and its relationship with ABCB1 expression and function in healthy Chinese subjects.

AIM: Interindividual epigenetic variation is likely to be an important mechanism contributing to the interindividual variability in the expression and function of ATP-binding cassette, sub-family B, member 1 (ABCB1). The aim of the present study was to explore the effect of interindividual epigenetic variability in the ABCB1 promoter on ABCB1 expression and function in healthy Chinese subjects. METHODS: Using bisulfite sequencing polymerase chain reaction (PCR) and chromatin immunoprecipitation assays, the DNA methylation and histone acetylation status of the ABCB1 promoter in stool DNA and exfoliated colonic epithelial cells of 157 healthy Chinese male volunteers was analysed. ABCB1 mRNA levels in colonic epithelial cells were detected by real-time PCR. The digoxin pharmacokinetics in subjects with different epigenetic profiles was investigated after a single oral administration of digoxin (0.5 mg). RESULTS: The methylation levels of ABCB1 promoter in stool DNA showed a significant interindividual variation, from 0.84% to 18.05%. A high methylation level of the ABCB1 promoter was closely related to the low levels of acetylated histone H3 and ABCB1 mRNA expression. In the high methylation group, the area under the concentration-time curves (AUC(0-4 h) and AUC(0-10 h) ) of digoxin was increased by 19% [95% confidence interval (CI) 10%, 31%; P = 0.024] and 13% (95% CI 8%, 26%; P = 0.026), respectively, and the peak concentration (Cmax ) of digoxin was increased by 30% (95% CI 12%, 41%; P = 0.021) compared with the low methylation group. CONCLUSIONS: The epigenetic modifications of the ABCB1 promoter show high interindividual variability in healthy Chinese subjects, and are closely related to the interindividual variation in ABCB1 mRNA expression and digoxin 0-4 h plasma concentrations in vivo.

CircMYBL1 suppressed acquired resistance to osimertinib in non-small-cell lung cancer.

Circular RNAs (circRNAs) play an important role in the development of acquired resistance to many anticancer drugs. We developed the Non-Small-Cell Lung Cancer (NSCLC) cell lines with acquired resistance to osimertinib, a third-generation of epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs), and evaluated the different expression profiles of circRNAs in osimertinib-sensitive and -resistant NSCLC cell lines using RNA sequencing (RNA-Seq). The expression of selected differentially expressed circRNAs was verified using quantitative real-time PCR (qRT-PCR) in paired osimertinib-sensitive and -resistant NSCLC cell lines, and in plasma samples of osimertinib-sensitive and -resistant NSCLC patients. We found that circMYBL1(has_circ_0136924) was downregulated after acquired resistance to osimertinib, inhibiting circMYBL1 expression facilitated the proliferation, migration, and invasion in osimertinib-sensitive NSCLC cells. CircMYBL1 may be a novel molecular biomarker and therapeutic target for osimertinib-resistant NSCLC.

The tsRNAs (tRFdb-3013a/b) serve as novel biomarkers for colon adenocarcinomas.

The tsRNAs (tRNA-derived small RNAs) are a novel class of small non-coding RNAs derived from transfer-RNAs. Colon adenocarcinoma (COAD) is the most malignant intestinal tumor. This study focused on the identification and characterization of tsRNA biomarkers in colon adenocarcinomas. Data processing and bioinformatic analyses were performed with the packages of R and Python software. The cell proliferation, migration and invasion abilities were determined by CCK-8 and transwell assays. Luciferase reporter assay was used to test the binding of tsRNA with its target genes. With computational methods, we identified the tRNA fragments profiles within COAD datasets, and discriminated forty-two differentially expressed tsRNAs between paired colon adenocarcinomas and non-tumor controls. Among the fragments derived from the 3' end of tRNA-His-GUG (a histidyl-transfer-RNA), tRFdb-3013a and tRFdb-3013b (tRFdb-3013a/b) were notably decreased in colon and rectum adenocarcinomas, especially, tRFdb-3013a/b might tend to be down-regulated in patients with lymphatic or vascular invasion present. The clinical survival of colorectal adenocarcinoma patients with low tRFdb-3013a/b expression was significantly worse than that of high expression patients. In colon adenocarcinoma cells, tRFdb-3013a could have inhibited cell proliferations, and reduced cell migration and invasion abilities. The enrichment analyses showed that most of tRFdb-3013a correlated-genes were enriched in the extracellular matrix associated GO terms, phagosome pathway, and a GSEA molecular signature pathway. Additionally, the 3'UTR of ST3GAL1 mRNA was predicted to contain the binding site of tRFdb-3013a/b, tRFdb-3013a/b might directly target and regulate ST3GAL1 expression in colon adenocarcinomas. These results suggested that tRFdb-3013a/b might serve as novel biomarkers for diagnosis and prognosis of colon adenocarcinomas, and act a key player in the progression of colon adenocarcinomas.

Romidepsin exhibits anti-esophageal squamous cell carcinoma activity through the DDIT4-mTORC1 pathway.

Esophageal squamous cell carcinoma (ESCC) is one of the most common human malignancies worldwide and is associated with high morbidity and mortality. Current treatment options are limited, highlighting the need for development of novel effective agents. Here, a high-throughput drug screening (HTS) was performed using ESCC cell lines in both two- and three-dimensional culture systems to screen compounds that have anti-ESCC activity. Our screen identified romidepsin, a histone deactylase inhibitor, as a potential anti-ESCC agent. Romidepsin treatment decreased cell viability, induced apoptosis and cell cycle arrest in ESCC cell lines, and these findings were confirmed in ESCC cell line-derived xenografted (CDX) mouse models. Mechanically, romidepsin induced transcriptional upregulation of DNA damage-inducible transcript 4 (DDIT4) gene by histone hyperacetylation at its promoter region, leading to the inhibition of mammalian target of rapamycin complex 1 (mTORC1) pathway. Furthermore, romidepsin exhibited better efficacy and safety compared to the conventional therapeutic drugs in ESCC patient-derived xenografted (PDX) mouse models. These data indicate that romidepsin may be a novel option for anti-ESCC therapy.

CircSETD3 mediates acquired resistance to gefitinib in non-small lung cancer cells by FXR1/ECT2 pathway.

BACKGROUND: Gefitinib is the first-line treatment for non-small cell lung cancer (NSCLC) harboring EGFR sensitive mutation. However, acquired resistance significantly limits its therapeutic efficacy. CircSETD3 has been reported to promote gefitinib resistance in NSCLC cells, however, its underlying mechanisms have not been fully clarified. METHODS: The expression of circSETD3 were detected in NSCLC patients who received gefitinib as first-line treatment, including 20 gefitinib-sensitive patients and 20 acquired gefitinib-resistant patients. Cell viability were examined by CCK8 assay. The mRNA and protein levels were detected by qRT-PCR and western blot. Using RNA pull-down assay followed by mass spectrometry to identified proteins that interact with circSETD3. The interaction between circSETD3 and fragile X-related protein-1 (FXR1) were further validated by RNA immunoprecipitation (RIP) and pull-down analysis. Fuorescence in situ hybridization (FISH) and immunofluorescence (IF) assays was used for the identification of sub-location of circSETD3 and FXR1 in cells. The effect of circSETD3 overexpression and knockdown on NSCLC tumor growth to gefitinib sensitivity was detected using the mouse xenograft model. RESULTS: CircSETD3 was significantly upregulated in gefitinib-resistant NSCLC cells, and decreased the gefitinib sensitivity in vitro and in vivo. Mechanically, circSETD3 facilitated FXR1 binding to its downstream mRNA target, epithelial cell-transforming sequence 2 (ECT2), promoting ECT2 mRNA decay, which further inhibited cellular apoptosis. CONCLUSION: CircSETD3/FXR1/ECT2 axis plays a critical role in the acquired resistance to gefitinib in NSCLC. Our results highlight the potential of circSETD3 as a biomarker and therapeutic target for NSCLC patients with acquired gefitinib resistance.

Lnc-TMEM132D-AS1 as a potential therapeutic target for acquired resistance to osimertinib in non-small-cell lung cancer.

Acquired resistance is a major obstacle to the therapeutic efficacy of osimertinib in non-small-cell lung cancer (NSCLC). Current knowledge about the role of long non-coding RNAs (lncRNAs) in this phenomenon is insufficient. In this study, we screened the differentially expressed lncRNAs between osimertinib-sensitive and -resistant NSCLC cell lines, and determined that lnc-TMEM132D-AS1 was significantly upregulated in osimertinib-resistant NSCLC cells, as well as in the plasma of osimertinib-resistant NSCLC patients. Lnc-TMEM132D-AS1 markedly decreased the osimertinib sensitivity of NSCLC cells. After osimertinib exposure, it increased the cell proliferation and colony formation, decreased the cell apoptosis, and induced M2/G-phase cell cycle arrest. After identifying its cytoplasmic localization, a functional lnc-TMEM132D-AS1-miRNA-mRNA interaction network and a protein-protein interaction (PPI) network were constructed to analyze its putative target genes and biological functions. Lnc-TMEM132D-AS1 could directly bind to miR-766-5p and lead to the upregulation of ectonucleoside triphosphate diphosphohydrolase-1 (ENTPD1), resulting in an increase in cell proliferation. Moreover, upregulated ENTPD1 was also associated with enhanced tumor infiltration of immunosuppressive cells and poor prognosis in NSCLC patients. In summary, lnc-TMEM132D-AS1 plays a crucial role in osimertinib resistance. It may serve as a prognostic biomarker and a potential therapeutic target for acquired resistance to osimertinib in NSCLC.

Ct-OATP1B3 promotes high-grade serous ovarian cancer metastasis by regulation of fatty acid beta-oxidation and oxidative phosphorylation.

High-grade serous ovarian cancer (HGSOC) is the most lethal gynecologic malignancy mainly due to its extensive metastasis. Cancer-type organic anion transporting polypeptide 1B3 (Ct-OATP1B3), a newly discovered splice variant of solute carrier organic anion transporter family member 1B3 (SLCO1B3), has been reported to be overexpressed in several types of cancer. However, the biological function of Ct-OATP1B3 remains largely unknown. Here, we reveal that Ct-OATP1B3 is overexpressed in HGSOC and promotes the metastasis of HGSOC in vivo and in vitro. Mechanically, Ct-OATP1B3 directly interacts with insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2), an RNA-binding protein, which results in enhancement of the mRNA stability and expression of carnitine palmitoyltransferase 1A (CPT1A) and NADH:Ubiquinone Oxidoreductase Subunit A2 (NDUFA2), leading to increased mitochondrial fatty acid beta-oxidation (FAO) and oxidative phosphorylation (OXPHOS) activities. The increased FAO and OXPHOS activities further facilitate adenosine triphosphate (ATP) production and cellular lamellipodia formation, which is the initial step in the processes of tumor cell migration and invasion. Taken together, our study provides an insight into the function and underlying mechanism of Ct-OATP1B3 in HGSOC metastasis, and highlights Ct-OATP1B3 as a novel prognostic marker as well as therapeutic target in HGSOC.

The tRNA-Cys-GCA Derived tsRNAs Suppress Tumor Progression of Gliomas via Regulating VAV2.

The tsRNAs (tRNA-derived small RNAs) are new types of small noncoding RNAs derived from tRNAs. Gliomas are well-known malignant brain tumors. The study focused on tsRNA characterizations within gliomas. Datasets processing, bioinformatics analyses, and visualizations were performed with the packages of Python and R. Cell proliferations were demonstrated via CCK8 assays and colony formation assays, and in vivo xenograft experiments. Dual-luciferase reporter assay was performed to confirm the binding of tsRNA with its targets. Via using bioinformatics approaches, the hundreds of tsRNAs with available expression abundance were identified in gliomas dataset, most of them derived from D-loop or T-loop fragments of tRNAs. Among tsRNAs derived from tRNA-Cys-GCA, tRFdb-3003a and tRFdb-3003b (tRFdb-3003a/b) were remarkably down-regulated in gliomas. The survival outcome of gliomas patients with low tRFdb-3003a/b expressions was notably worse than that of high-expression patients. In glioma cells, tRFdb-3003a could suppress cells proliferation and colony formation ability. In vivo, tRFdb-3003a suppressed the tumor growth of xenograft gliomas. Enrichment analyses displayed the tRFdb-3003a-related mRNAs were enriched in the specific GO terms, spliceosome and autophagy pathways, and three GSEA molecular signatures. Mechanically, 3'-UTR regions of VAV2 mRNA were predicted to contain the binding positions of tRFdb-3003a/b, tRFdb-3003a and tRFdb-3003b was effective to reduce the relative luciferase activity of cells with VAV2 wild-type reporter. Overexpression of tRFdb-3003a/b could down-regulated the expression levels of VAV2 protein and mRNA in glioma cells. The tRNA-Cys-GCA derived tRFdb-3003a and tRFdb-3003b might act as key player in tumor progressions of gliomas; tRFdb-3003a/b might directly bind to VAV2 and regulate VAV2 expressions in gliomas.

Screening Circular RNAs Related to Acquired Gefitinib Resistance in Non-small Cell Lung Cancer Cell Lines.

Background: Gefitinib is a tyrosine kinase inhibitor (TKI) of epidermal growth factor receptor (EGFR) used to treat EGFR mutation-positive patients with non-small cell lung cancer (NSCLC). However, the efficacy of gefitinib is limited by the development of acquired resistance. Studies have shown that circular RNAs (circRNAs) are involved in the acquired resistance to many anticancer agents. However, the expression profiles and functions of circRNAs in gefitinib resistance in NSCLC are poorly understood so far. Methods: In this study, circRNA expression profiling was explored in two gefitinib-resistant NSCLC cell lines (HCC827/GR and PC9/GR) and their parental sensitive cells (HCC827 and PC9) using high-throughput RNA sequencing. Quantitative real-time PCR (qRT-PCR) was used to confirm the expression of selected differentially expressed circRNAs. Bioinformatic tools including gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), network analysis, and Kaplan-Meier plotter database were used to predict the functions and pathways of these differentially expressed circRNAs. Results: We identified 46 and 56 differentially expressed circRNAs in HCC827/GR and PC9/GR cell lines, respectively, compared with those in their parental cell lines. Gene ontology and KEGG pathway analysis identified that the host linear transcripts of these differentially expressed circRNAs were involved in many critical biological pathways and molecular functions. We found that hsa_circ_0000567 was consistently up-regulated, and hsa_circ_0006867 was consistently down-regulated in two resistant cell lines. We further used hsa_circ_0000567 and hsa_circ_0006867 as key circRNAs to construct circRNA-miRNA-mRNA networks. Several target mRNAs of these two circRNAs had been shown to significantly associate with the overall survival of patients with lung cancer. Conclusions: In this study, we generated the comprehensive expression and functional profiles of the differentially expressed circRNAs between gefitinib-resistant and -sensitive NSCLC cells, and showed that dysregulation of circRNAs might play an important role in the development of acquired resistance to gefitinib in NSCLC.

Genome-wide identification and characterization of long non-coding RNAs involved in acquired resistance to gefitinib in non-small-cell lung cancer.

Acquired resistance is a major obstacle to the therapeutic efficacy of gefitinib in non-small-cell lung cancer (NSCLC). Current knowledge about the role of long non-coding RNAs (lncRNAs) in this phenomenon is insufficient. In this study, we searched RNA sequencing data for lncRNAs associated with acquired resistance to gefitinib in NSCLC, and constructed a functional lncRNA-mRNA co-expression network and protein-protein interaction (PPI) network to analyze their putative target genes and biological functions. The expression levels of 14 outstanding dysregulated lncRNAs and mRNA were verified using real-time PCR. Changes in the expression levels of 39 lncRNAs and 121 mRNAs showed common patterns in our two pairs of gefitinib-sensitive and gefitinib-resistant NSCLC cell lines. The co-expression network included 1235 connections among these common differentially expressed lncRNAs and mRNAs. The significantly enriched signaling pathways based on dysregulated mRNAs were mainly involved in the Hippo signaling pathway; proteoglycans in cancer; and valine, leucine, and isoleucine biosynthesis. The results show that LncRNAs play an important part in acquired gefitinib resistance in NSCLC by regulating mRNA expression and function, and may represent potential new molecular biomarkers and therapeutic targets for gefitinib-resistant NSCLC.

circSETD3 Contributes to Acquired Resistance to Gefitinib in Non-Small-Cell Lung Cancer by Targeting the miR-520h/ABCG2 Pathway.

Gefitinib is a first-line treatment for patients with non-small-cell lung cancer (NSCLC), but acquired resistance is a major obstacle to its therapeutic efficacy, and the underlying mechanisms are not fully elucidated. Recent studies have indicated that circular RNAs play a crucial role in chemoresistance, but their expression and function in NSCLC cells with acquired resistance to gefitinib are largely unknown. In this study, we determined that circSETD3 was significantly upregulated in gefitinib-resistant NSCLC cell lines and the plasma of gefitinib-resistant NSCLC patients. circSETD3 markedly decreased the gefitinib sensitivity of NSCLC cells both in vitro and in nude mice xenografts. It could directly bind to miR-520h and lead to the upregulation of ATP-binding cassette subfamily G member 2 (ABCG2), an efflux transporter of gefitinib, resulting in a reduced intracellular gefitinib concentration. Moreover, we reported that the downregulation of serine/arginine splicing factor 1 (SRSF1) contributed to, at least in part, the increased expression of circSETD3 in NSCLC cells with acquired resistance to gefitinib. Taken together, our findings indicated that circSETD3 may serve as a prognostic biomarker and a potential therapeutic target for acquired resistance to gefitinib in NSCLC.

Prognostic Values Of Preoperative Serum CEA And CA125 Levels And Nomograms For Young Breast Cancer Patients.

BACKGROUND: Young breast cancer patients have poor prognosis compared to older patients in both overall survival (OS) and loco-regional failure-free survival. Carcinoembryonic antigen (CEA) and Cancer antigen 125 (CA125) have been widely used, but their prognostic value in young breast cancer patients remains unknown. The objectives of this study were to evaluate the prognostic value of preoperative CEA and CA125 serum levels and to build nomograms for better prognostic prediction of young Chinese breast cancer patients using both tumor markers. METHODS: We included 576 young breast cancer patients (≤40 years at diagnosis) and collected their preoperative information. The best cut-off values of the CEA and CA125 were identified with receiver operating characteristic (ROC) curves. Univariate and multivariate analyses were used to identify the relative risks of factors for the overall survival (OS), and disease-free survival (DFS), and nomograms were constructed based on these identified factors. RESULTS: The best cut-off values for CEA and CA125 in young breast cancer patients was 3.38 ng/mL and 19.38 U/mL, respectively. Kaplan-Meier analysis showed that young patients with low levels of CEA and/or CA125, had longer OS and DFS. Multivariate analysis suggested that both CEA and CA125 levels were independent predictive elements for OS. Nomograms were built and showed a better predictive ability for OS (AUC = 0.856) and DFS (AUC = 0.702) in young breast cancer patients. CONCLUSION: Preoperative serum CEA and CA125 levels could be the independent prognostic factors for OS, and the nomograms including these two variables provide more personal forecasts information to help physicians optimize treatment for young breast cancer patients better.

Curcumin reverses doxorubicin resistance via inhibition the efflux function of ABCB4 in doxorubicin­resistant breast cancer cells.

Doxorubicin is one of the most widely used chemotherapy agents for the treatment of breast cancer. However, the development of doxorubicin resistance limits the long­term treatment benefits in patients with breast cancer. Curcumin, a well­known dietary polyphenol derived from the rhizomes of turmeric (Curcuma longa), enhances the sensitivity of breast cancer cells to chemotherapeutic agents; however, the mechanisms underlying this phenomenon remain unclear. The aim of the present study was to evaluate the effect of curcumin on chemoresistance in doxorubicin­resistant breast cancerMCF­7/DOX and MDA­MB­231/DOX cell lines. Cell Counting Kit­8, monolayer transport, western blot and ATPase activity assays were performed during the study. The results revealed that curcumin significantly enhanced the effect of doxorubicin in doxorubicin­resistant breast cancer cells. The intracellular accumulation of doxorubicin was substantially increased following curcumin treatment in doxorubicin­resistant breast cancer cells, in a manner that was inversely dependent on the activity of ATP binding cassette subfamily B member 4 (ABCB4). Treatment with a combination of curcumin and doxorubicin decreases the efflux of doxorubicin in ABCB4­overexpressing cells. Furthermore, curcumin inhibited the ATPase activity of ABCB4 without altering its protein expression. In conclusion, curcumin reversed doxorubicin resistance in human breast cancer MCF­7/DOX and MDA­MB­231/DOX cells by inhibiting the ATPase activity of ABCB4. The study highlights the promising use of curcumin as a chemosensitizer in the treatment of breast cancer.

P4HB and PDIA3 are associated with tumor progression and therapeutic outcome of diffuse gliomas.

Diffuse gliomas are the most common type of primary brain and central nervous system (CNS) tumors. Protein disulfide isomerases (PDIs) such as P4HB and PDIA3 act as molecular chaperones for reconstructing misfolded proteins, and are involved in endoplasmic reticulum stress and the unfolded protein response. The present study focused on the role of P4HB and PDIA3 in diffuse gliomas. Analysis of GEO and HPA data revealed that the expression levels of P4HB and PDIA3 were upregulated in glioma datasets. their increased expression was then validated in 99 glioma specimens compared with 11 non-tumor tissues. High expression of P4HB and PDIA3 was significantly correlated with high Ki-67 and a high frequency of the TP53 mutation. Kaplan-Meier survival curve and Cox regression analyses showed that glioma patients with high P4HB and PDIA3 expression had a poor survival outcome, P4HB and PDIA3 could be independent prognostic biomarkers for diffuse gliomas. In vitro, knockdown of PDIA3 suppressed cell proliferation, induced cell apoptosis, and decreased the migration of glioma cells. Furthermore, downregulation of P4HB and PDIA3 may contribute to improve the survival of patients who receive chemotherapy and radiotherapy. The data suggest that high expression of P4HB and PDIA3 plays an important role in glioma progression, and could predict the survival outcome and therapeutic response of glioma patients. Therefore, protein disulfide isomerases may be explored as prognostic biomarkers and therapeutic targets for diffuse gliomas.

Novel osteogenic growth peptide C-terminal pentapeptide grafted poly(d,l-lactic acid) improves the proliferation and differentiation of osteoblasts: The potential bone regenerative biomaterial.

Poly(d,l-lactic acid) (PDLLA) is widely used for bone regenerative engineering, because of its proven biocompatibility and biodegradability. However, the major limitation of PDLLA is its cell recognition and low hydrophilicity. The objective of this study was to develop a novel bioactive poly(d,l-lactic acid) tethered with osteogenic growth peptide (OGP), which has been confirmed as one of the important growth factors related to bone repair/regeneration. The biomimetic material modification methods were utilized that maleic anhydride-modified poly(d,l-lactic acid) (MPLA) as raw material, the active C-terminal pentapeptide OGP(10-14) were covalently grafted onto the side chain of MPLA through amide reaction using 1­ethyl­3­(3­dimethyl aminopropyl) carbodiimide hydrochloride (EDC) and N­hydroxysuccinimide (NHS) as the condensing agent to produce a new biopolymer (OGP(10-14)-MPLA). The OGP(10-14)-MPLA were further characterized with the Fourier transform infrared spectrometry, amino acid analyzer, elementary analysis, X-ray photoelectron spectroscopy. The results revealed that OGP(10-14) was successfully modified MPLA and its coupling efficiency was 12.40%. The data from both contact angle and water absorption showed the better hydrophilicity of OGP(10-14)-MPLA, compared with MPLA. Also, we found that OGP(10-14)-MPLA could improve the proliferation, differentiation, and mineralization of osteoblasts, indicating that the novel OGP(10-14)-MPLA has the better biocompatibility and is more osteoinductive. In conclusion, the OGP(10-14) modified MPLA have the potential for bone regenerative engineering.

Overexpression of ABCB4 contributes to acquired doxorubicin resistance in breast cancer cells in vitro.

PURPOSE: Doxorubicin is one of the most active agents in the first-line therapy for metastatic breast cancer, but its utility is partially limited by the frequent emergence of doxorubicin resistance. In this study, we aimed to investigate the role of ATP-binding cassette sub-family B, member 4 (ABCB4) in acquired doxorubicin resistance in breast cancer cells, as well as its potential mechanism. METHODS: In doxorubicin-sensitive and -resistant breast cancer cell lines MCF-7 and MDA-MB-231, the expression levels of ABCB4 were detected using real-time quantitative PCR and Western blot analysis, the DNA methylation and histone acetylation status of ABCB4 gene were investigated by bisulfite-sequencing PCR (BSP) and chromatin immunoprecipitation (ChIP) assays, and the doxorubicin sensitivity and intracellular doxorubicin accumulation were observed using cell cytotoxicity assay and flow cytometry. In Madin-Darby Canine Kidney (MDCKII) cells, In vitro transport assay was used to assess the ABCB4-mediated transport of doxorubicin. RESULTS: ABCB4 was overexpressed in doxorubicin-resistant breast cancer cells compared to their doxorubicin-sensitive counterparts, which was associated with reduced DNA methylation as well as increased histone acetylation at the ABCB4 promoter. ABCB4 could actively pump doxorubicin out of the cells, and knockdown of ABCB4 increased doxorubicin sensitivity and intracellular accumulation in doxorubicin-resistant breast cancer cells. CONCLUSIONS: Our results indicate that ABCB4 is overexpressed in breast cancer cells with acquired doxorubicin resistance, which could be attributed, at least partially, to the epigenetic modifications of ABCB4 gene. ABCB4 mediates the efflux transport of doxorubicin, and contributes to the acquired resistance of doxorubicin in breast cancer cells.

Unifying mechanism in the initiation of breast cancer by metabolism of estrogen (Review).

Excessive exposure to estrogen is associated with increased risk of breast cancer. The mechanisms of carcinogenesis in the breast caused by estrogen metabolism include formation of depurinating adducts which are released from DNA to generate apurinic sites, and production of reactive oxygen species (ROS). Excess ROS not only exerts genotoxicity by indirectly increasing genomic instability, but also stimulates progression of mammary carcinogenicity by inducing a redox­associated signaling pathway. Estrogen metabolism enzymes serve an important role in estrogen metabolism. Alterations in the expression and activity of estrogen metabolism enzymes may influence estrogen metabolism homeostasis. The present review discusses the process of estrogen metabolism, the role of estrogen metabolites and ROS in breast carcinogenesis, and the effect of metabolism enzyme polymorphisms on generation of pro­carcinogens and breast cancer susceptibility.

Combined Influence of Genetic Polymorphism and DNA Methylation on ABCB1 Expression and Function in Healthy Chinese Males.

BACKGROUND AND OBJECTIVES: It is well known that the expression and function of ATP-binding cassette transporter B1 (ABCB1) show high interindividual variability, but the reasons have not yet been fully elucidated. In this study, combined influence of genetic polymorphism and DNA methylation on ABCB1 mRNA expression and digoxin pharmacokinetics in healthy Chinese males was analyzed. METHODS: A total of 93 subjects who were homozygous for the ABCB1 1236-2677-3435 TTT or CGC haplotype were enrolled in this study. DNA methylation status of the ABCB1 promoter and ABCB1 mRNA expression level in exfoliated intestinal epithelial cells were analyzed using bisulfite sequencing PCR and real-time PCR. The pharmacokinetics of digoxin in subjects were investigated after administration of a single oral dose of digoxin 0.5 mg. RESULTS: The DNA methylation levels of ABCB1 promoter showed no significant difference between TTT/TTT and CGC/CGC carriers (P = 0.54). Subjects with TTT/TTT haplotype pair and high methylation status (TTT/TTT-HM) showed a significantly lower ABCB1 mRNA level compared to other subjects. Compared with TTT/TTT-HM subgroup, the area under the plasma concentration-time curve from time zero to 72 h (AUC0-72) of digoxin was decreased by 26.9 %, the maximum plasma concentration (C max) was decreased by 25 % and the apparent oral clearance (CL/F) was increased by 21.2 % in CGC/CGC-LM subgroup. The values of time to maximum concentration (t max) and terminal elimination half-life (t 1/2) showed no significant difference. CONCLUSIONS: Both genetic polymorphism and DNA methylation variation should be taken into consideration to explain the interindividual variability in ABCB1 expression and function more clearly.

Berberine enhances the anti­tumor activity of tamoxifen in drug­sensitive MCF­7 and drug­resistant MCF­7/TAM cells.

Berberine, an isoquinoline alkaloid, has been previously demonstrated to possess anti­breast cancer properties. Tamoxifen is widely used in the prevention and treatment of estrogen receptor-positive breast cancer. Thus, the aim of the present study was to assess whether berberine enhanced the anticancer effect of tamoxifen, and the underlying mechanism involved in this combined effect in tamoxifen-sensitive (MCF-7) and tamoxifen-resistant (MCF-7/TAM) cells using MTS, flow cytometry and western blot assays. The results indicated that berberine demonstrated dose­ and time­dependent anti­proliferative activity in MCF­7 and MCF­7/TAM cells. Furthermore, the combination of berberine and tamoxifen induced cell growth inhibition more effectively than tamoxifen alone. The present study also demonstrated that combinational treatment is more effective in inducing G1 phase arrest and activating apoptosis compared tamoxifen alone, which may be due to upregulation of P21 expression and downregulation of the B­cell CLL/lymphoma 2(Bcl­2)/Bcl­2 associated X protein ratio. The results of the present study suggested that berberine may potentially be useful as an adjuvant agent in cancer chemotherapy to enhance the effect of tamoxifen, which will be useful for anti­tumor therapy and further research.