Functional mechanism of hypoxia-like conditions mediating resistance to ferroptosis in cervical cancer cells by regulating KDM4A SUMOylation and the SLC7A11/GPX4 pathway.

The discovery of ferroptosis has unveiled new perspectives for cervical cancer (CC) management. We elucidated the functional mechanism of hypoxia-like conditions in CC cell ferroptosis resistance. CC cells were subjected to normoxia or hypoxia-like conditions, followed by erastin treatment to induce ferroptosis. The assessment of cell viability/ferroptosis resistance was performed by MTT assay/Fe2+, MDA, and glutathione measurement by colorimetry. KDM4A/SUMO1/Ubc9/SENP1 protein levels were determined by Western blot. Interaction and binding sites between KDM4A and SUMO1 were analyzed and predicted by immunofluorescence/co-immunoprecipitation and GPS-SUMO 1.0 software, with the target relationship verified by mutation experiment. SLC7A11/GPX4/H3K9me3 protein levels, and H3K9me3 level in the SLC7A11 gene promoter region were determined by RT-qPCR and Western blot/chromatin immunoprecipitation. H3H9me3/SLC7A11/GPX4 level alterations, and ferroptosis resistance after KDM4A silencing or KDM4A K471 mutation were assessed. Hypoxia-like conditions increased CC cell ferroptosis resistance and KDM4A, SUMO1, and Ubc9 protein levels, while it decreased SENP1 protein level. KDM4A and SUMO1 were co-localized in the nucleus, and hypoxia-like conditions promoted their interaction. Specifically, the K471 locus of KDM4A was the main locus for SUMO1ylation. Hypoxia-like conditions up-regulated SLC7A11 and GPX4 expression levels and decreased H3K9me3 protein level and H3K9me3 abundance in the SLC7A11 promoter region. KDM4A silencing or K471 locus mutation resulted in weakened interaction between KDM4A and SUMO1, elevated H3K9me3 levels, decreased SLC7A11 expression, ultimately, a reduced CC cell ferroptosis resistance. CoCl2-stimulated hypoxia-like conditions enhanced SUMO1 modification of KDM4A at the K471 locus specifically, repressed H3K9me3 levels, and up-regulated SLC7A11/GPX4 to enhance CC cell ferroptosis resistance.

Performance of DNA methylation analysis in the detection of high-grade cervical intraepithelial neoplasia or worse (CIN3+): a cross-sectional study.

It is commonly accepted that host genes show high methylation in cervical intraepithelial neoplasia 3 (CIN3) or worse (CIN3+). However, study quality varies, as does the clinical performance of markers in different populations. We aimed to validate candidate gene DNA methylation with standardized testing methods in the same batch of samples. We first compared the performance of 16 DNA methylation markers for detecting CIN3+ in the 82-sample training set, including 24 subjects with ≤ CIN1, 10 subjects with CIN2, 23 subjects with CIN3, and 25 subjects with cervical cancer (CC). Then five methylation markers were selected and subsequently validated among an independent set of 74 subjects, including 47 subjects with ≤ CIN1, 13 subjects with CIN2, 6 subjects with CIN3, and 8 subjects with CC. The results in the validation set revealed that methylation analysis of the SOX1 (SOX1m) showed a superior level of clinical performance (AUC = 0.879; sensitivity = 85.7%; specificity = 90.0%). SOX1m had better accuracy than cytology, with a reduced referral rate (23.0% vs. 31.4%) and a lower number of overtreatment (5 vs. 13) cases among high-risk human papillomavirus (hrHPV)-positive women. Importantly, among hrHPV-positive and SOX1m-negative women, only 1 CIN3 patient was at risk for follow-up after 1 year, whereas 1 CIN3 patient and 1 CC patient were at risk among hrHPV-positive and cytology-negative women. In this investigation, we screened 16 reported methylation markers to provide a basis for future studies related to potential precancerous lesion/cancer methylation markers in the Chinese population. The study also revealed that SOX1m has optimal CIN3+ detection performance, suggesting that it may be a promising biomarker for detecting CIN3+ in the Chinese population.

ZNF671 methylation test in cervical scrapings for cervical intraepithelial neoplasia grade 3 and cervical cancer detection.

Effective triage of high-risk human papillomavirus (hrHPV)+ women is warranted to avoid unnecessary referral and overtreatment. Molecular triage tests have recently begun to impact cervical intraepithelial neoplasia grade 3 (CIN3) or cervical cancer (CC), termed CIN3+, detection. We find that zinc finger protein 671 methylation (ZNF671m) test has superior performance for CIN3+ detection in all single molecular triage tests, including HPV16/18 genotyping, paired box gene 1 methylation (PAX1m), and ZNF671m, in the training set. Using ZNF671m test instead of Thinprep cytologic test (TCT) as a single triage strategy or as a combined triage strategy with HPV16/18 genotyping has achieved comparable sensitivity but higher specificity for CIN3+ detection among 391 hrHPV+ women in the validation set. Little attention has been paid to the women with hrHPV- status but detected CIN3+. We find that the CIN3+ risk after a negative result could be reduced further by triage using ZNF671m in hrHPV- patients.

Chronic Inflammation Pathway NF-κB Cooperates with Epigenetic Reprogramming to Drive the Malignant Progression of Glioblastoma.

Without an effective strategy for targeted therapy, glioblastoma is still incurable with a median survival of only 15 months. Both chronic inflammation and epigenetic reprogramming are hallmarks of cancer. However, the mechanisms and consequences of their cooperation in glioblastoma remain unknown. Here, we discover that chronic inflammation governs H3K27me3 reprogramming in glioblastoma through the canonical NF-κB pathway to target EZH2. Being a crucial mediator of chronic inflammation, the canonical NF-κB signalling specifically directs the expression and redistribution of H3K27me3 but not H3K4me3, H3K9me3 and H3K36me3. Using RNA-seq screening to focus on genes encoding methyltransferases and demethylases of histone, we identify EZH2 as a key methyltransferase to control inflammation-triggered epigenetic reprogramming in gliomagenesis. Mechanistically, NF-κB selectively drives the expression of EZH2 by activating its transcription, consequently resulting in a global change in H3K27me3 expression and distribution. Furthermore, we find that co-activation of NF-κB and EZH2 confers the poorest clinical outcome, and that the risk for glioblastoma can be accurately molecularly stratified by NF-κB and EZH2. It is notable that NF-κB can potentially cooperate with EZH2 in more than one way, and most importantly, we demonstrate a Synergistic effect of cancer cells induced by combinatory inhibition of NF-κB and EZH2, which both are frequently over-activated in glioblastoma. In summary, we uncover a functional cooperation between chronic inflammation and epigenetic reprogramming in glioblastoma, combined targeting of which by inhibitors guaranteed in safety and availability furnishes a potent strategy for effective treatment of this fatal disease.

Circular RNA CDR1as disrupts the p53/MDM2 complex to inhibit Gliomagenesis.

BACKGROUND: Inactivation of the tumor suppressor p53 is critical for pathogenesis of glioma, in particular glioblastoma multiforme (GBM). MDM2, the main negative regulator of p53, binds to and forms a stable complex with p53 to regulate its activity. Hitherto, it is unclear whether the stability of the p53/MDM2 complex is affected by lncRNAs, in particular circular RNAs that are usually abundant and conserved, and frequently implicated in different oncogenic processes. METHODS: RIP-seq and RIP-qPCR assays were performed to determine the most enriched lncRNAs (including circular RNAs) bound by p53, followed by bioinformatic assays to estimate the relevance of their expression with p53 signaling and gliomagenesis. Subsequently, the clinical significance of CDR1as was evaluated in the largest cohort of Chinese glioma patients from CGGA (n = 325), and its expression in human glioma tissues was further evaluated by RNA FISH and RT-qPCR, respectively. Assays combining RNA FISH with protein immunofluorescence were performed to determine co-localization of CDR1as and p53, followed by CHIRP assays to confirm RNA-protein interaction. Immunoblot assays were carried out to evaluate protein expression, p53/MDM2 interaction and p53 ubiquitination in cells in which CDR1as expression was manipulated. After AGO2 or Dicer was knocked-down to inhibit miRNA biogenesis, effects of CDR1as on p53 expression, stability and activity were determined by immunoblot, RT-qPCR and luciferase reporter assays. Meanwhile, impacts of CDR1as on DNA damage were evaluated by flow cytometric assays and immunohistochemistry. Tumorigenicity assays were performed to determine the effects of CDR1as on colony formation, cell proliferation, the cell cycle and apoptosis (in vitro), and on tumor volume/weight and survival of nude mice xenografted with GBM cells (in vivo). RESULTS: CDR1as is found to bind to p53 protein. CDR1as expression decreases with increasing glioma grade and it is a reliable independent predictor of overall survival in glioma, particularly in GBM. Through a mechanism independent of acting as a miRNA sponge, CDR1as stabilizes p53 protein by preventing it from ubiquitination. CDR1as directly interacts with the p53 DBD domain that is essential for MDM2 binding, thus disrupting the p53/MDM2 complex formation. Induced upon DNA damage, CDR1as may preserve p53 function and protect cells from DNA damage. Significantly, CDR1as inhibits tumor growth in vitro and in vivo, but has little impact in cells where p53 is absent or mutated. CONCLUSIONS: Rather than acting as a miRNA sponge, CDR1as functions as a tumor suppressor through binding directly to p53 at its DBD region to restrict MDM2 interaction. Thus, CDR1as binding disrupts the p53/MDM2 complex to prevent p53 from ubiquitination and degradation. CDR1as may also sense DNA damage signals and form a protective complex with p53 to preserve p53 function. Therefore, CDR1as depletion may play a potent role in promoting tumorigenesis through down-regulating p53 expression in glioma. Our results broaden further our understanding of the roles and mechanism of action of circular RNAs in general and CDR1as in particular, and can potentially open up novel therapeutic avenues for effective glioma treatment.

Long noncoding RNA LINC00152 promotes cell proliferation through competitively binding endogenous miR-125b with MCL-1 by regulating mitochondrial apoptosis pathways in ovarian cancer.

Recently, an increasing number of studies have focused on the key function of long noncoding RNAs (lncRNAs) in biological activity. Abnormal lncRNA expression was found to relate to the development and pathogenesis of multiple cancers. LncRNA LINC00152 served as an oncogene in multiple cancers; however, its role in ovarian cancer remains unknown. In our research study, LINC00152 was upregulated in ovarian cancer tissues and cell lines. An increasing LINC00152 level was positively correlated with the histological grade, clinical stage, and poor prognosis of ovarian cancer patients. In addition, knockdown of LINC00152 reduced cell growth, induced cell apoptosis, and suppressed tumor growth. Moreover, we revealed that LINC00152 and Myeloid cell leukemia-1 (MCL-1) were targeted by miR-125b and had the same miR-125b combining site. The miR-125b level was negatively correlated with the expression of LINC00152, while MCL-1 was positively related to the LINC00152 level. MiR-125b could affect LINC00152 levels as evaluated by qRT-PCR. Finally, we affirmed that LINC00152 mediated cell proliferation by affecting MCL-1 expression and MCL-1-mediated mitochondrial apoptosis pathways and by working as a competitive endogenous RNA (ceRNA) of miR-125b. In summary, based on ceRNA theory, the combined research on miR-125b and MCL-1, and taking LINC00152 as a new study point, we provide new insight into the molecular mechanism of reversing cell proliferation in ovarian cancer.

Upregulation of p27Kip1 by demethylation sensitizes cisplatin-resistant human ovarian cancer SKOV3 cells.

Ovarian cancer has a poor prognosis due to its chemoresistance, and p27Kip1 (p27) has been implicated in tumor prognosis and drug-resistance. However, the regulatory mechanisms of p27 in drug­resistance in ovarian cancer remain unknown. The current study successfully established chemoresistant cell lines using paclitaxel (TAX), cisplatin (DDP) and carboplatin (CBP) in SKOV3 ovarian cancer cells. The results indicated that the expression levels of p27 were dramatically downregulated in chemoresistant cells. However, 5-aza-2'-deoxycytidine (5-aza) treatment restored p27 expression in DDP-resistant cells, and increased their sensitivity to DDP. In addition, it was observed that the methylation of DDP­resistant cells, which was downregulated by 5­aza treatment, was significantly higher compared with SKOV3 cells. Additionally, the overexpression of p27 arrested the cell cycle in S phase and promoted an apoptotic response to DDP. In conclusion, p27 was involved in chemoresistance of SKOV3 cells. Upregulated p27 expression induced by demethylation may enhance sensitivity to DDP through the regulation of the cell cycle.

Systematic characterization of lncRNAs' cell-to-cell expression heterogeneity in glioblastoma cells.

Glioblastoma (GBM) is the most common malignant adult brain tumor generally associated with high level of cellular heterogeneity and a dismal prognosis. Long noncoding RNAs (lncRNAs) are emerging as novel mediators of tumorigenesis. Recently developed single-cell RNA-seq provides an unprecedented way for analysis of the cell-to-cell variability in lncRNA expression profiles. Here we comprehensively examined the expression patterns of 2,003 lncRNAs in 380 cells from five primary GBMs and two glioblastoma stem-like cell (GSC) lines. Employing the self-organizing maps, we displayed the landscape of the lncRNA expression dynamics for individual cells. Further analyses revealed heterogeneous nature of lncRNA in abundance and splicing patterns. Moreover, lncRNA expression variation is also ubiquitously present in the established GSC lines composed of seemingly identical cells. Through comparative analysis of GSC and corresponding differentiated cell cultures, we defined a stemness signature by the set of 31 differentially expressed lncRNAs, which can disclose stemness gradients in five tumors. Additionally, based on known classifier lncRNAs for molecular subtypes, each tumor was found to comprise individual cells representing four subtypes. Our systematic characterization of lncRNA expression heterogeneity lays the foundation for future efforts to further understand the function of lncRNA, develop valuable biomarkers, and enhance knowledge of GBM biology.

Icariin stimulates the proliferation of rat bone mesenchymal stem cells via ERK and p38 MAPK signaling.

Bone mesenchymal stem cells (BMSCs) are able to differentiate into multi types of lineages, so they have been widely applied in the stem cell transplantation. The BMSCs are usually needed to be expanded before transplantation due to their limited content in bone marrow. It has recently been reported that Icariin (ICA), a major constituent of flavonoids from the Chinese medical herb Epimedium brevicornum Maxim, promotes the proliferation of various types of differentiated cells. However, whether ICA can enhance BMSCs proliferation and the possible underlying mechanisms are still unknown. After being isolated and purified from rat bone marrow, cultured BMSCs are stimulated with different concentrations of ICA. The cytotoxicity of ICA is evaluated by the Cell Counting Kit-8 (CCK-8) assay method and the ICA optimal concentration for BMSCs proliferation is determined at 320 µg/L. Our work reveals that ICA induces an obvious phosphorylation of ERK and p38 kinases in BMSCs, no matter serum exists or not. Inhibition of ERK or p38 MAPK signaling by their specific inhibitors PD98059 or SP600125, respectively, not only prevents the activation of these kinases, but also attenuates cell proliferation induced by ICA. Furthermore, the downstream transcription factors of MAPK pathway, Elk1, Stat3, c-Myc and Fos, are also monitored by RT-PCR, and our results show that among them, Elk1 and c-Myc are significantly upregulated after ICA treatment. Taken together, our results demonstrate that ICA promotes the proliferation of rat BMSCs through activating ERK and p38 MAPK signaling which further leads to upregulation of their downstream transcription factors Elk1 and c-Myc. Our work provides a novel effective way to expand the content of BMSCs in vitro, which casts light on clinical applications of stem cell transplantation in the future.

Urinary microRNA-30a-5p is a potential biomarker for ovarian serous adenocarcinoma.

MicroRNAs (miRNAs) can serve as biomarkers in human cancer. To determine the clinical value of urinary miRNAs for ovarian serous adenocarcinoma, we collected urine samples from 39 ovarian serous adenocarcinoma patients, 26 patients with benign gynecological disease and 30 healthy controls. The miRNA microarray data showed that only miR-30a-5p was upregulated and 37 miRNAs were downregulated in the urine samples of ovarian serous adenocarcinoma patients, when compared to healthy controls, which was confirmed after conducting quantitative PCR. The upregulation of urinary miR-30a-5p was closely associated with early stage of ovarian serous adenocarcinoma as well as lymphatic metastasis. Receiver operator characteristic (ROC) analysis demonstrated the potential use of urinary miR-30a-5p as a diagnostic marker for ovarian serous adenocarcinoma. Furthermore, a lower urine level of miR-30a-5p was found in 20 gastric cancer and 20 colon carcinoma patients when compared to ovarian serous adenocarcinoma, suggesting that the upregulation of urinary miR-30a-5p may be specific for ovarian serous adenocarcinoma. miR-30a-5p was also upregulated in ovarian serous adenocarcinoma tissues and cell lines, while urinary miR-30a-5p from ovarian cancer patients was notably reduced following the surgical removal of ovarian serous adenocarcinoma, suggesting that urinary miR-30a-5p was derived from the ovarian serous adenocarcinoma tissue. Notably, miR-30a-5p was concentrated with exosomes from the ovarian cancer cell supernatant or urine from ovarian serous adenocarcinoma patients, supporting a pathway for excretion into the urine. The results also showed that the knockdown of miR-30a-5p significantly inhibited the proliferation and migration of ovarian cancer cells. In summary, to the best of our knowledge, the present study provided the first evidence of increased miR-30a-5p in the urine of ovarian serous adeno-carcinoma patients, while the inhibition of miR-30a-5p suppressed the malignant phenotypes of ovarian cancer in vitro. Therefore, miR-30a-5p serves as a promising diagnostic and therapeutic target for ovarian serous adenocarcinoma.

Musashi-1 Expression is a Prognostic Factor in Ovarian Adenocarcinoma and Correlates with ALDH-1 Expression.

The presence of cancer stem-like cells (CSCs) has been demonstrated to be associated with tumor metastasis, chemoresistance, and rapid recurrence of various tumors. The impact of CSC-related markers in the metastasis and prognosis of ovarian cancer has not been well established. In this study, the protein expression of musashi-1 and ALDH1 was measured using immunohistochemistry. Results demonstrated that the percentage of positive musashi-1 and ALDH1 expression were significantly higher in ovarian serous adenocarcinomas, mucinous adenocarcinomas and clear cell adenocarcinomas than in cystadenomas and normal tissues. The percentage of positive musashi-1 and ALDH1 expression were significantly lower in patients identified with clinical stage I or II ovarian adenocarcinomas without lymph node metastasis compared to patients with clinical stage III or IV tumors and lymph node metastasis. The expression of musashi-1 and ALDH1 was found to be highly consistent in ovarian adenocarcinomas. Univariate Kaplan-Meier analysis showed a negative correlation between musashi-1 or ALDH1 expression and overall survival. Multivariate Cox regression analysis showed that positive expression of musashi-1 or ALDH1 in ovarian adenocarcinoma was an independent predictor of poor prognosis. Our study suggested that musashi-1 and ALDH1 expression are closely related to metastasis of ovarian adenocarcinoma. The positive expression of musashi-1 and ALDH1 might be a poor-prognostic factor of ovarian adenocarcinoma.

The role of miR-205 in the VEGF-mediated promotion of human ovarian cancer cell invasion.

OBJECTIVE: Our objective was to investigate a miRNA pathway that acts downstream of VEGF-induced invasion of ovarian cancer cells. METHOD: We used two paired high and low metastatic serous ovarian cancer cells to demonstrate the role of miR-205 in VEGF-induced invasion of ovarian cancer cells and to investigate the gene targets of miR-205. RESULTS: Our previous comparative proteomics studies showed that VEGF decreased the expression of Ezrin and Lamin A/C, and this result was validated in the present study using qPCR and Western blotting. Then we found that VEGF enhanced the invasiveness of and inhibited apoptosis in ovarian cancer cells as assessed by transwell invasion assays and Annexin V-FITC immunostaining, respectively. VEGFR was also expressed in ovarian cancer cells, as assessed by immunocytochemical staining. Furthermore, using the dual-luciferase report assay system, we demonstrated that miR-205 targeted Ezrin and Lamin A/C. MiR-205 was up-regulated in ovarian cancer cells exposed to VEGF, as determined by miRNA microarray analysis and verified by qPCR. MiR-205 promoted the invasion and proliferation of ovarian cancer cells. CONCLUSION: Our data reveal a new potential pathway in which VEGF promotes the invasion of ovarian cancer cells, partially via the down-regulation of Ezrin and Lamin A/C caused by increased expression of miR-205.

Loss of lamin A but not lamin C expression in epithelial ovarian cancer cells is associated with metastasis and poor prognosis.

OBJECTIVE: To elucidate the different roles of lamin A and lamin C in the metastasis of epithelial ovarian cancer (EOC) by examining their expression in EOC tissues and cell lines and their correlations with clinicopathological features. METHODS: The expression of lamin A and lamin C was assessed in ovarian tissues from 61 EOC patients and 13 normal, 14 benign controls, respectively, using immunohistochemistry. Two pairs of EOC cell lines: HO-8910, HO-8910PM, SKOV-3 and SKOV-3ip were also examined to see the differential expression patterns of lamin A and lamin C. RESULTS: Lamin A expression was significantly lower in EOC tissues than that in normal and benign ovarian tissues (p<0.05), while lamin C expression was not. Lamin A expression level was closely associated with pathological grades, clinical stages, peritoneal metastasis and lymph node metastasis (all p<0.05). The progression-free survival rate of the EOC patients with low lamin A expression level was remarkably lower than that of the EOC patients with high expression level (p<0.05). Lamin A detected by PCR, Western Blot and immunocytochemistry also showed a significantly lower expression level in HO-8910PM than that in HO-8910 (p<0.05), but not for lamin C. There was no difference between SKOV-3 and SKOV-3ip cells. CONCLUSIONS: The results suggested that loss of lamin A but not lamin C expression in EOC was related to metastasis and poor prognosis. Lamin A may play a critical role in the metastasis of EOC.

Upregulation of Limk1 caused by microRNA-138 loss aggravates the metastasis of ovarian cancer by activation of Limk1/cofilin signaling.

LIM kinase 1 (Limk1) is associated with cell prolife-ration and metastasis and its dysregulated expression has been observed in many types of cancer. The present study aimed to examine the role of Limk1 in the development of ovarian cancer, as well as the underlying molecular mechanism involved. The results showed that increased Limk1 and decreased miR-138 expression co-existed in ovarian cancer. Furthermore, knockout of Limk1 or the overexpression of miR-138 resulted in reduced cell invasion and migration, while silencing of miR-138 led to enhancement of the invasion and migration of ovarian cancer cells. Cell growth was inhibited by the overexpression of miR-138, although not by the knockout of Limk1. miR-138 directly targeted Limk1 and inhibited ovarian cancer cell growth by PCNA and Bcl-2. Moreover, Limk1/cofilin/p-cofilin is likely a critical signaling pathway involving in miR-138 modulation of ovarian cancer cell metastasis. The results provide evidence supporting miR-138/Limk1 as a novel diagnostic or therapeutic target for ovarian cancer.

Axl and prostasin are biomarkers for prognosis of ovarian adenocarcinoma.

In this study, the protein levels of Axl and prostasin in malignant neoplasms of the ovary and their clinicopathologic significance were investigated. The protein levels of Axl and prostasin in ovarian adenocarcinomas (n = 80), serous cystadenoma (n = 15), mucinous cystadenomas (n = 15), and normal ovary tissues (n = 10) were measured using immunohistochemistry. The percentage of Axl-positive cases was significantly higher in ovarian adenocarcinoma (61.3%) than in mucinous adenoma tissues (13.3%; P < .001) and normal tissues (0.0%; P = .000). The percentage of prostasin-positive cases was significantly lower in ovarian adenocarcinoma (42.5%) than in mucinous adenoma tissues (86.7%; P = .000) and normal tissues (100%; P = .000). The expression of Axl was significantly lower in cases with G1 tumor and TNM stage I or II tumor with no lymph node metastasis than in cases with G3 tumor and TNM stage III or IV tumor with lymph node metastasis (P < .05 or P < .01). However, the expression pattern of prostasin was opposite to that of Axl (P < .01 or P < .01). Univariate Kaplan-Meier analysis showed a negative correlation between Axl expression (P = .000) and overall survival and a positive correlation between prostasin expression (P = .000) and overall survival. Multivariate Cox regression analysis showed that Axl-positive expression and prostasin-negative expression are independent bad prognostic predictors in ovarian adenocarcinoma. Our study suggested that Axl and prostasin expression may be closely related to carcinogenesis, metastasis, and prognosis of ovarian adenocarcinoma.

miR-7 and miR-218 epigenetically control tumor suppressor genes RASSF1A and Claudin-6 by targeting HoxB3 in breast cancer.

Many microRNAs have been implicated as key regulators of cellular growth and differentiation and have been found to dysregulate proliferation in human tumors, including breast cancer. Cancer-linked microRNAs also alter the epigenetic landscape by way of DNA methylation and post-translational modifications of histones. Aberrations in Hox gene expression are important for oncogene or tumor suppressor during abnormal development and malignancy. Although recent studies suggest that HoxB3 is critical in breast cancer, the putative role(s) of microRNAs impinging on HoxB3 is not yet fully understood. In this study, we found that the expression levels of miR-7 and miR-218 were strongly and reversely associated with HoxB3 expression. Stable overexpression of miR-7 and miR-218 was accompanied by reactivation of tumor suppressor genes including RASSF1A and Claudin-6 by means of epigenetic switches in DNA methylation and histone modification, giving rise to inhibition of the cell cycle and clone formation of breast cancer cells. The current study provides a novel link between overexpression of collinear Hox genes and multiple microRNAs in human breast malignancy.

[Pathogenicity of Ureaplasma urealyticum serotype 3 in genital tract of mice].

OBJECTIVE: To study the pathogenicity of Ureaplasma urealyticum serotype 3 (UU3) with different concentration in the genital tract of the mice. METHODS: A total of 156 Kunming mice were divided into 4 groups randomly, including group A, B, C (48 mice in every experimental group) and control group (12 mice in control group). UU 3 at concentration of 1x10(7) copy/g (group A), 1x10(6) copy/g (group B), 1x10(5) copy/g (group C) were inoculated into 48 mice in every experimental group intravaginally, in the mean time, culture medium of UU was given into 12 mice in control group. They were necropsied at 1, 3, 7, 14, 21, 35 days of postinoculation randomly, which included 8 mice of every experimental group and 2 mice of control group every time, and to detect UU3 expression from cervical secretions by FQ-PCR and observing the pathogenicity rate in tissues of cervix, endometrium, fallopian tube by light microscope and calculate the morbidity rate. RESULTS: (1) The total positive rates of UU3 were 63% (30/48) in group A, 50% (24/48) in group B, 17% (8/48) in group C, which showed a significant difference (P<0.01). And at 1, 3, 7, 14, 21, 35 days of postinoculation, the positive rates of group A were 8/8, 7/8, 6/8, 5/8, 4/8 and 0, group B were 7/8, 5/8, 5/8, 4/8, 3/8 and 0, group C were 3/8, 2/8, 2/8, 1/8, 0 and 0; all mice in control group were zero. At all time points, there were statistical difference in the positive rate among three experimental groups only at 1 day (P<0.05). (2) In the positive mice, their UU3 quantity concentration at 1, 3, 7, 14, 21 days were 1.70x10(7), 8.26x10(6), 4.04x10(6), 2.86x10(6), and 2.41x10(5) copy/g in group A; 3.75x10(6), 2.56x10(6), 1.37x10(6), 6.72x10(5), and 1.12x10(5) copy/g in group B, and 1.45x10(5), 1.07x10(5), 5.43x10(4), 4.68x10(3), and 0 copy/g in group C. There were statistical difference among experimental groups at all time points except 21 days (P<0.05). Comparing the concentration among all time points of every group, both group A and B showed a significant difference (P<0.05), group C didn't reach it (P>0.05). (3) The total pathogenicity rates of three groups were significant different at 7-35 days, which were 56% (18/32) in group A, 44% (14/32) in group B, 6% (2/32) in group C (P<0.01). And at 7, 14, 21, 35 days of postinoculation, the pathogenicity rates in group A were 5/8, 5/8, 4/8 and 4/8, group B were 4/8, 4/8, 3/8 and 3/8, group C were 1/8, 0, 1/8 and 0; all mice in control group were zero, which demonstrated significant difference only at 14 days (P<0.05), no other statistical difference were observed (P>0.05). CONCLUSIONS: The pathogenicity of UU3 varies with different concentration in genital tract of mice. When UU3 concentration is more than 1x10(6) copy/g, the susceptibility to infection was intensified significantly.