Identification of mutations in the F8 and F9 gene in families with haemophilia using targeted high-throughput sequencing

INTRODUCTION

At present, many methods are available for the genetic diagnosis of haemophilia, including indirect linkage analysis, direct sequencing. However, these methods are time-consuming, labourious, and limited in their application. Therefore, the development of new, more effective techniques is necessary.

AIM

To detect the F8 and F9 gene mutations in patients with haemophilia and their female relatives in 29 haemophilia A (HA) and 11 haemophilia B (HB) families.

METHODS

FVIII

C and FIX:C were analyzed using one-stage method, and factor VIII and factor IX inhibitors were tested using the Bethesda method. Intron 22 and one inversions were identified using long-distance polymerase chain reaction (PCR) and standard PCR. Non-inversion mutations of the F8 and F9 gene were identified by targeted high-throughput sequencing. All mutations were verified by Sanger sequencing.

RESULTS

Intron 22 inversion was detected in eight HA families and intron one inversion was detected in one HA family. Apart from the inversion mutations, 20 mutations were identified in HA families, including 17 previously reported and three novel mutations: c.5724G>A (p.Trp1908*), c.6116-1_6120delGAGTGTinsTCC (p.Lys2039Ilefs*13), and c.5220-2A>C. We found a complex rearrangement in HA: intron one inversion concomitant with exon one deletion. In HB, eight recurrent mutations were detected, including six missense mutations and two nonsense mutations.

CONCLUSION

Targeted high-throughput sequencing is an effective technique to detect the F8 and F9 gene mutations, especially for the discovery of novel mutations. The method is highly accurate, time-saving and shows great advantage in uncovering large deletion mutations and also in distinguishing the wild-type genotype and heterozygous large deletions.

[Temperature modifies the acute effect of particulate air pollution on mortality in Jiang'an district of Wuhan]

OBJECTIVE

To analyze the temperature modification effect on acute mortality due to particulate air pollution.

METHODS

Daily non-accidental mortality, cardiovascular mortality, and respiratory mortality data were obtained from Jiang'an District Center for Disease Control and Prevention. Daily meteorological data on mean temperature and relative humidity were collected from China Meteorological Data Sharing Service System. The daily concentration of particulate matter was collected from Wuhan Environmental Monitoring center. By using the stratified time-series models, we analyzed effects of particulate air pollution on mortality under different temperature zone from 2002 to 2010, meanwhile comparing the difference of age, gender and educational level, in Wuhan city of China.

RESULTS

High temperature (daily average temperature > 33.4 ℃) obviously enhanced the effect of PM10 on mortality. With 10 μg/m(3) increase in PM10 concentrations, non-accidental, cardiovascular, and respiratory mortality increased 2.95% (95%CI: 1.68%-4.24%), 3.58% (95%CI: 1.72%-5.49%), and 5.07% (95%CI: 2.03%-9.51%) respectively. However, low temperature (daily average temperature <-0.21 ℃) enhanced PM10 effect on respiratory mortality with 3.31% (95% CI: 0.07%-6.64%) increase. At high temperature, PM10 had significantly stronger effect on non-accidental mortality of female aged over 65 and people with high educational level groups. With an increase of 10 μg/m(3), daily non-accidental mortality increased 4.27% (95% CI:2.45%-6.12%), 3.38% (95% CI:1.93%-4.86%) and 3.47% (95% CI:1.79%-5.18%), respectively. Whereas people with low educational level were more susceptible to low temperature. A 10 μg/m(3) increase in PM10 was associated with 2.11% (95% CI: 0.20%-4.04%) for non-accidental mortality.

CONCLUSIONS

Temperature factor can modify the association between the PM10 level and cause-specific mortality. Moreover, the differences were apparent after considering the age, gender and education groups.

Radiation-enhancing effect of sodium glycididazole in patients suffering from non-small cell lung cancer with multiple brain metastases: A randomized, placebo-controlled study

PURPOSE

Median survival of patients with brain metastases from non-small cell lung cancer is poor. This study was to investigate the radiation-enhancing effect of sodium glycididazole combined with whole-brain radiotherapy of multiple brain metastases from non-small cell lung cancer.

PATIENTS AND METHODS

Sixty-four patients with multiple brain metastases from non-small cell lung cancer were included: the study group (n=32) received whole-brain radiotherapy combined with sodium glycididazole at a dose of 700mg/m(2) intravenous infusion 30minutes before radiotherapy, three times a week; the control group (n=32) only received whole-brain radiotherapy. The primary end point was central nervous system (CNS) progression-free survival and overall survival. The treatment-related toxicity was also recorded.

RESULTS

The CNS disease control rate was better (90.6% vs 65.6%, P=0.016) in the study group than in the control group at 3 month of follow-up. The median CNS progression-free survival time was longer in the study group than in the control group (7.0 months vs 4.0 months, P=0.038). There was no significant difference of the median overall survival time between the study group and the control group (11.0 months vs 9.0 months, P=0.418). On the other hand, the treatment-related toxicity showed no statistically significant difference between these two groups (P>0.05).

CONCLUSIONS

The study indicated that sodium glycididazole was an effective, promising radiation-enhancing agent that improved CNS disease control rate, extended the median CNS progression-free survival time and was well tolerated in patients suffering from non-small cell lung cancer with multiple brain metastases.

RNA-Seq analysis for the potential targets and molecular mechanisms of 17 β-estradiol in squamous cell lung carcinoma

The efficacy of 17 β-estradiol (E2) was valid in some cancers, while its effects on squamous cell lung carcinoma (SCLC) were still unclear. The aim of our study was to investigate the potential targets and molecular mechanisms of E2 in SCLC cells.Two RNA libraries from human lung carcinoma cells (SK-MES-1) with and without E2 treatment were constructed and sequenced. The differentially expressed genes (DEGs) between cells with or without E2 treatment were identified by cuffdiff software. Hierarchical Clustering Analysis (HCA) was performed for displaying gene expression changes and classification. Furthermore, enrichment analyses of Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway and Gene Ontology Biological Process (GO BP) terms were performed through DAVID. The protein-protein interaction (PPI) network was constructed through STRING. Additionally, differentially expressed lncRNAs were also selected by cuffdiff software.Total 129 DEGs including 58 up- and 71 down- regulated genes were obtained. Cancer-related pathways including small cell lung cancer, hypertrophic cardiomyopathy (HCM) and pathways in cancer and biological processes including regulation of phosphorus metabolic process, protein localization and nucleus organization were enriched. The PPI network with 113 nodes and 312 edges was constructed. CASP3, ITGA2, COL4A6, PML and CDC25B were identified as hub nodes which had more interactions with others in the PPI network. Furthermore, eight up-regulated and ten down-regulated lncRNAs were selected.CASP3, ITGA2 and Lnc-DLK1-4:31 (one of down-regulated lncRNAs) might play pivotal roles in E2 treated SCNC cells by influencing cell apoptosis, angiogenesis and cell invasion respectively.

[Effects of autologous adipose-derived stromal vascular fraction on erectile dysfunction of hypertensive rats]

OBJECTIVE

To study the effect of autologous adipose stromal vascular fraction (SVF) injection into corpora cavernosa on the hypertension-associated erectile dysfunction (ED) in rats and its possible mechanism.

METHODS

Healthy male spontaneously hypertensive rats (SHR) at 30-week (n=40) and homologous rats with normal blood pressure (WKY) (n=20) were selected. Noninvasive blood pressure meter was used to measure the systolic blood pressure (SBP) at the tail. Cervical subcutaneous injection of apomorphine was applied to test penile erectile function. The rats with ED were divided into hypertension-associated ED rats treated with autologous SVF injection into corpora cavernosa (ED-SHR-SVF group) (n=8) and hypertension-associated ED rats treated with phosphate buffered saline (PBS) injection into corpora cavernosa (ED-SHR-PBS group) (n=8). The intracavernosal pressure (ICP) was measured in each group. Western blot and RT-PCR were conducted to test protein and mRNA expressions of endothelial nitric oxide synthase (eNOS) in corpora cavernosa.

RESULTS

The tail SBP in SHR rats was significantly higher than that in WKY rats ((197.47±6.82) mmHg vs (125.23±4.65) mmHg, P<0.05). The erectile rate in SHR rats was 60% (24/40), and that in WKY rats was 100% (20/20). After 5 V electrical stimulation, the ICP in the ED-SHR-SVF group was significantly higher than in the ED-SHR-PBS group ((83.42±3.21) mmHg vs (52.37±3.11) mmHg, P<0.05). The protein and mRNA expressions of eNOS in the ED-SHR-SVF group were significantly higher than in the ED-SHR-PBS group (0.43±0.03 vs 0.18±0.05, 0.92±0.05 vs 0.41±0.06, both P<0.05).

CONCLUSIONS

High blood pressure can cause ED in rats, which could be mitigated by autologous SVF injection. The mechanism may be related to up-regulation of eNOS expression in corpus cavernosa.

High expression of HIF-2α and its anti-radiotherapy effect in lung cancer stem cells

Hypoxia-inducible factor-2 alpha (HIF-2α) has been shown to regulate cell stemness, although the expression and effects of HIF-2α in lung cancer stem cells remained unclear. This study investigated HIF-2α expression in lung cancer stem cells, as well as the relationship between HIF-2α expression and radioresistance in lung cancer cells. Stem-like cells (CD133(+)) in the non-small-cell lung cancer cell line A549 were enriched by serum-free culture conditions, and CD133(+) cells were sorted via fluorescence-activated cell sorting. A549 cells were treated with middle-infrared radiation, and the level of HIF-2α expression was determined by a quantitative polymerase chain reaction assay and western blot analysis. The level of HIF-2α expression in tissue sections from 50 cases of clinically confirmed non-small-cell lung cancer was determined via immunohistochemical analysis, and its correlation with prognosis after radiotherapy was analyzed. HIF-2α levels in CD133(+) cells were significantly higher than those in CD133(-) cells (P = 0.032). However, after radiation treatment, these levels were significantly upregulated in both CD133(+) and CD133(-) cells (P = 0.031 and P = 0.023, respectively). After irradiation, the proportions of apoptotic, dead, and autophagic CD133(+) A549 cells were considerably lower than those of CD133(-) A549 cells (P < 0.05). Furthermore, the recovery of carcinoembryonic antigen to pre-radiation levels was more rapid in lung cancer patients with high levels of HIF-2α expression, and these patients had shorter survival times (P = 0.018). HIF-2α is highly expressed in lung cancer stem cells, which may lead to radioresistance. In conclusion, HIF-2α is a potential prognostic marker for lung cancer.

Expression patterns of Doppel in differential ovine PRNP genotypes: quantification using real-time RT-PCR

Doppel is a homologue of cellular prion protein (PrP)-like protein (PrPC). Different tissue samples were collected from the central nervous system plus four regions of lymphoid system, eleven regions of digestive tract and two reproductive organs from four ARR/ARQ and four ARH/ARQ sheep, genotypes of the PrP gene. Total RNA was isolated from these samples, and Doppel mRNA was quantified by real-time RT-PCR using SYBR Green. Doppel mRNA expression was higher in the ovary, hypothalamus and brain than in other tissues, and it significantly differed between the two genotypes in brain, ileum, cecum, rectum, colon, and uterus. This study demonstrated that Doppel mRNA expression in sheep with ARR/ARQ or ARH/ARQ genotypes was very different. These findings could be helpful in future studies of the relationship between PrP and Doppel.

Traditional karyotyping vs copy number variation sequencing for detection of chromosomal abnormalities associated with spontaneous miscarriage

OBJECTIVES

To compare the performance of traditional G-banding karyotyping with that of copy number variation sequencing (CNV-Seq) for detection of chromosomal abnormalities associated with miscarriage.

METHODS

Products of conception (POC) were collected from spontaneous miscarriages. Chromosomal abnormalities were detected using high-resolution G-banding karyotyping and CNV sequencing. Quantitative fluorescent polymerase chain reaction analysis of maternal and POC DNA for short tandem repeat (STR) markers was used to both monitor maternal cell contamination and confirm the chromosomal status and sex of the miscarriage tissue.

RESULTS

A total of 64 samples of POC, comprising 16 with an abnormal and 48 with a normal karyotype, were selected and coded for analysis by CNV-Seq. CNV-Seq results were concordant for 14 (87.5%) of the 16 gross chromosomal abnormalities identified by karyotyping, including 11 autosomal trisomies and three sex chromosomal aneuploidies (45,X). Of the two discordant results, a 69,XXX polyploidy was missed by CNV-Seq, although supporting STR marker analysis confirmed the triploidy. In contrast, CNV-Seq identified a sample with 45,X karyotype as a 45,X/46,XY mosaic. In the remaining 48 samples of POC with a normal karyotype, CNV-Seq detected a 2.58-Mb 22q deletion associated with DiGeorge syndrome and nine different smaller CNVs of no apparent clinical significance.

CONCLUSIONS

CNV-Seq used in parallel with STR profiling is a reliable and accurate alternative to karyotyping for identifying chromosome copy number abnormalities associated with spontaneous miscarriage.

Treatment of Moyamoya disease by multipoint skull drilling for indirect revascularization combined with mobilization of autologous bone marrow stem cells

This study discusses the clinical efficacy of multipoint skull drilling for indirect revascularization combined with mobilization of autologous bone marrow stem cells and use of simvastatin in the treatment of moyamoya disease. Seventy-eight patients [control group (group A), 39 patients; experimental group (group B), 39 patients] with moyamoya disease were selected. Group A underwent indirect revascularization, and group B, in addition to indirect revascularization, received alternate subcutaneous injections from day 7 post-surgery. The number and differentiation of the mobilized bone marrow stem cells were detected by the proportion of hematopoietic progenitor cell (HPCs) in mononuclear cells (MNCs) in the peripheral blood. There was no statistical difference in the BI (80.2 ± 13.7) and NIHSS (6.7 ± 2.3) scores between the groups before treatment (P > 0.05). The CSS score of group B was 13.5 ± 0.6 and there was a statistical significance compared to group A (18.2 ± 0.8) (P < 0.05). There was no statistical difference in the proportion of CD34+ CDl33+ cells in MNCs in peripheral blood before surgery between the two groups (P > 0.05) and the proportions of CD34+ CDl33+ cells in MNCs in peripheral blood in groups A and B at 30 days after surgery were significantly higher than those before surgery (P < 0.05). Treating moyamoya disease by multipoint skull drilling for indirect revascularization combined with mobilization of autologous bone marrow stem cells and simvastatin is a safe and effective method as it can promote recovery of neurological functions and improve patients' daily living abilities and quality of life.

Regulation of the Heme Oxygenase-1/carbon monoxide system by hydrogen sulfide in murine coxsackievirus B3-induced myocarditis

To explore the impact of hydrogen sulfide (H2S) on the heme oxygenase&mdash;1 (HO&mdash;1)/carbon monoxide (CO) system in coxsackie virus B3 (CVB3)&mdash;induced myocarditis. A total of 80 Balb/c mice were divided randomly into four groups designated N, C, P and S. Group N served as the negative control while groups C, P, and S were infected with CVB3 to induce myocarditis. Group P was additionally treated with DL&mdash;propargylglycine (PAG) to inhibit the generation of H2S while Group S was treated with NaHS, an H2S donor. Ten days after infection, heart sections were scored for histopathology. We also measured carboxyhemoglobin (COHb) levels in the blood and HO&mdash;1 expression by immunohistochemistry. 1. Each CVB3&mdash;infected group (C, P, and S) exhibited increased pathology, COHb levels, and HO&mdash;1 expression compared to uninfected controls. 2. Regarding histopathology, the score of group P was worse, while that of group S was better, than that of group C. 3. The P group COHb level was lower than group C, while the S group COHb level was higher than group C. 4. Positive HO&mdash;1 expression was seen in group C with reduced expression in group P and increased expression in group S. 5. A positive correlation was observed between the COHb concentration and HO&mdash;1expression; alternatively, a negative correlation was found between the histopathologic scores and both the concentration of COHb and the expression level of HO&mdash;1. Modulation of H2S can play a regulatory role in the pathogenesis of VMC by impacting the HO&mdash;1/CO pathway.

Risk factors associated with inhibitor development in Chinese patients with haemophilia B

INTRODUCTION

Inhibitor development is a severe complication of factor IX substitution treatment for haemophilia B (HB). Current research examined the association between inhibitor development and F9 genotypes and polymorphisms in immune response genes in Chinese HB patients.

MATERIALS AND METHODS

11 inhibitor-positive HB patients and 41 inhibitor-negative HB patients were enrolled. Direct sequencing, copy number variation (CNV) detection and fragment length analysis were applied to identify F9 genotypes and 15 polymorphisms in immune response genes.

RESULTS

7 patients developed high titer inhibitors, with 5 of them having histories of consecutive exposure to FIX products on demand for at least 5 days. Allergic reactions/anaphylaxis to prothrombin complex concentrates (PCC) occurred in 3 patients before inhibitors were detected. Five nonsense mutations (E54X, R75X, Q185X, R298X and R379X), two large deletions (E1~6del and E1~8del) and one missense mutation (S411G) were identified in patients with inhibitors. Missense mutations had a low odds ratio for FIX inhibitors development (IOR) of 0.078 (P = 0.02), while nonsense mutation presented a high IOR of 8.500 (P = 0.0044). The frequency of allele T in CD44(95102) (A/T) was significantly higher in inhibitor-negative patients, with OR of 0.324 (P = 0.04).

CONCLUSIONS

Nonsense mutations conferred a higher risk for while allele T in CD44(95102) (A/T) might play a protective role against inhibitor development in Chinese HB patients.

Serum C-reactive protein predicts poor prognosis in patients with locoregionally advanced nasopharyngeal carcinoma treated with chemoradiotherapy

BACKGROUND

We aimed to evaluate the association of serum C-reactive protein (crp) with prognosis in patients with locoregionally advanced nasopharyngeal carcinoma treated with chemoradiotherapy.

METHODS

We retrospectively reviewed 79 patients with locoregionally advanced nasopharyngeal carcinoma (cT3-4N0-3M0) treated with chemoradiotherapy. Chemoradiotherapy consisted of external-beam radiotherapy to the nasopharynx (70-80 Gy), the lymph node-positive area (60-70 Gy), and the lymph node-negative area (50-60 Gy) combined with 3 cycles of various platinum-based regimens delivered at 3-week intervals. Elevated crp was defined as more than 8 mg/L. The survival rate was calculated using the Kaplan-Meier method, and univariate and multivariate analyses (Cox proportional hazards model) were used to identify factors significantly associated with prognosis.

RESULTS

During the median follow-up of 3.9 years (range: 1-5.5 years), 23 patients died from nasopharyngeal cancer. The 5-year cancer-specific survival (css) rate was 62.90%. Before chemoradiotherapy, 18 patients had high serum crp; the css rate in that subgroup was significantly worse than the rate in the remaining patients (p = 0.0002). Multivariate analysis showed that crp was an independent prognostic indicator of css, with a hazard ratio of 3.04 (95% confidence interval: 1.22 to 7.55; p = 0.017). Among the 18 patients with elevated serum crp, 9 achieved normal serum crp after chemoradiotherapy, of whom 5 remained living with no evidence of recurrence or metastasis during follow-up. By contrast, the remaining 9 patients in whom serum crp did not normalize after chemoradiotherapy died within 4.2 years.

CONCLUSIONS

Elevated serum crp before treatment predicts poor prognosis in patients with locoregionally advanced nasopharyngeal carcinoma treated with chemoradiotherapy.

96 EFFECT OF MOF GENE ON PREIMPLANTATION DEVELOPMENT OF PIG PARTHENOGENETIC EMBRYOS

The Mof gene (males absent on the first) is crucial to X-chromosome dosage compensation in the fly. It acts specifically to catalyse acetylation of histone H4 lysine 16 (H4K16ac) as one histone acetyltransferase of the MYST family, playing essential roles during mammalian development. However, little is known about Mof gene in pigs. The present study was designed to explore effects of Mof on pre-implantation development of pig parthenogenetic embryos obtained as reported by Cao et al. (2012 Zygote 20, 229–236). Immunofluorescent staining was performed to examine protein expression level of porcine Mof (pMof) and H4K16ac, and fluorescent intensity was measured by Image J software (NIH, Bethesda, MD, USA). Data are presented as mean ± standard error, and statistical analyses of the fluorescent intensity value, embryo development rate, and quality were performed using ANOVA with SPSS software (version 15.0, SPSS Inc., Chicago, IL, USA), and P-value <0.05 was considered significant. First, the coding sequence (CDS) of the pMof gene was cloned and the spatio-temporal expression patterns of the CDS were determined in pig oocytes, early embryos, and other tissues. A 1471-bp-long cDNA of pMof was obtained with 99.34% and 98.25% amino acid sequence homology and 92.88% and 88.96% nucleotide sequence homology to the human and mouse MOF homologues. We observed that pMof is expressed predominantly in oocytes and early embryos but at low levels in sperm and other organs. We found that pMof decreased from pronuclear to 8-cell stages and remained low until the blastocyst stage based on RT-qPCR results (n = 10 for each stage embryos). In contrast, pMof protein expression as examined by immunofluorescent staining (n = 15 for each stage embryos) remained high throughout the pre-implantation development period. After porcine embryonic genome activation, pMOF remained detectable in 4-cell (n = 10) and 8-cell (n = 10) embryos despite amanitin treatment for 24 h. Thus, the mRNA level of MOF was not decreased after transcription inhibition suggesting that MOF is a maternal gene. To assess functional significance, we examined the expression of H4K16ac, a target of pMof, and found that the level of H4K16ac was constantly low from pronuclear to morula stage, but increased dramatically in blastocysts. When we knocked down pMOF by cytoplasmic injection of siRNA into porcine MII oocytes, rate and cell number of blastocysts declined significantly [blastocyst rate: uninjected (n = 228) v. negative-siRNA (n = 220) v. MOF-siRNA (n = 230) = 65.8 ± 3.75% v. 57.5 ± 4.30% v. 46.3 ± 5.72%; cell numbers: uninjected v. negative-siRNA v. MOF-siRNA = 84.73 ± 5.25 v. 77 ± 5.50 v. 55.08 ± 6.56]. A marker for DNA double-strand breaks and repair, γ-H2AX, increased in parallel to more apoptotic cells. Knockdown of MOF reduced H4K16ac. Overall, pMof is highly conserved among human, mouse, and pig; pMof is essential to pre-implantational development of pig parthenogenetic embryos involved in regulating H4K16ac.Research was supported by NSFC (31272442).

Knockdown of NF-κB p65 subunit expression suppresses growth of nude mouse lung tumor cell xenografts by activation of Bax apoptotic pathway

Nuclear factor-kappaB (NF-κB) is an important transcriptional factor and regulates a variety of pathophysiologic process involved in cell survival and death. The present study assesses the effects of NF-κB p65 subunit knockdown in suppression of nude mouse lung tumor cell xenografts and understands the underlying molecular events.A nude mouse Lewis lung carcinoma cell xenograft model was established and the mice were intraperitoneally injected with NF-κB p65 siRNA and sacrificed after two weeks of tumor cell injection. Tumor xenografts were harvested for TUNEL, Western blot, and qRT-PCR analyses.Compared to the PBS-treated or the negative control (NC) siRNA-treated mice, tumor xenograft weight and volume was significantly decreased in the NF-κB p65 siRNA-treated mice. The TUNEL positive (apoptosis) cells in xenograft sections were 45 ± 5 in PBS and 38 ± 3 in NC siRNA, but increased to 271 ± 11 in p65 siRNA-treated mice. Compared to the PBS or the NC mice, levels of Bax mRNA and protein in tumor xenografts were significantly upregulated in p65 siRNA-treated mice. Knockdown of NF-κB p65 subunit expression significantly inhibited the growth of nude mouse Lewis tumor cell xenografts by induction of tumor cell apoptosis and significantly up-regulation of pro-apoptotic protein Bax expression. Future study will confirm the current data and targeting NF-κB p65 subunit expression as a potential therapeutic strategy in treating human lung cancer.

KEYWORDS

NF-κB, lung cancer, apoptosis, small interfering RNA, xenografts.

MiR-873 regulates ERα transcriptional activity and tamoxifen resistance via targeting CDK3 in breast cancer cells

miRNAs (microRNAs) are frequently and aberrantly expressed in many cancers. MiR-873 has been revealed to be downregulated in colorectal cancer and glioblastoma. However, its function remains unclear. Here we report that miR-873 is downregulated in breast tumor compared with normal tissue. Enforced expression of miR-873 decreases the transcriptional activity of ER (estrogen receptor)-α but not ERβ through the modulation of ERα phosphorylation in ER-positive breast cancer cells. We also found that miR-873 inhibits breast cancer cell proliferation and tumor growth in nude mice. Reporter gene assays revealed cyclin-dependent kinase 3 (CDK3) as a direct target of miR-873. CDK3 was shown to be overexpressed in breast cancer and phosphorylate ERα at Ser104/116 and Ser118. Furthermore, we found that Mir-873 inhibits ER activity and cell growth via targeting CDK3. Interestingly, miR-873 was observed to be downregulated in tamoxifen-resistant MCF-7/TamR cells, while CDK3 is overexpressed in these cells. More importantly, re-expression of miR-873 reversed tamoxifen resistance in MCF-7/TamR cells. Our data demonstrate that miR-873 is a novel tumor suppressor in ER-positive breast cancer and a potential therapeutic approach for treatment of tamoxifen-resistant breast cancer.