Circular RNAs (circRNAs) have emerged as vital regulators in the chemoresistance of diverse human tumors, including ovarian cancer. In the present study, we attempted to explore the function of circ_CELSR1 in paclitaxel resistance of ovarian cancer. Quantitative real-time PCR (qRT-PCR) was conducted for the expression of circ_CELSR1, miR-149-5p and salt inducible kinase 2 (SIK2). Cell Counting Kit-8 (CCK-8) assay was performed to evaluate the half-maximal inhibitory concentration (IC 50 ) of paclitaxel and cell viability. Colony formation assay was adopted for cell colony formation. Flow cytometry analysis was conducted to analyze cell cycle process and apoptosis. Western blot assay was utilized to determine the protein levels. RNA immunoprecipitation (RIP) and dual-luciferase reporter assays were conducted to verify the association between miR-149-5p and circ_CELSR1 or SIK2. Murine xenograft model assay was carried out to determine the effect of circ_CELSR1 in paclitaxel resistance in vivo. Circ_CELSR1 was upregulated in paclitaxel-resistant ovarian cancer tissues and cells. Circ_CELSR1 knockdown enhanced paclitaxel sensitivity and cell apoptosis and repressed cell viability, colony formation and cell cycle process in paclitaxel-resistant ovarian cancer cells. For mechanism analysis, circ_CELSR1 could positively modulate SIK2 expression via sponging miR-149-5p. MiR-149-5p inhibition effectively restored the impacts of circ_CELSR1 knockdown on paclitaxel resistance and cell progression in paclitaxel-resistant ovarian cancer cells. MiR-149-5p overexpression suppressed paclitaxel resistance and cell progression in paclitaxel-resistant ovarian cancer cells by interacting with SIK2. In addition, circ_CELSR1 silencing impeded paclitaxel resistance of ovarian cancer in vivo. Circ_CELSR1 improved the resistance of ovarian cancer to paclitaxel by regulating miR-149-5p/SIK2 axis.

Background/Aims: Circulation long non-coding RNAs (lncRNAs) have emerged recently as major players in tumor biology and might be applied for cancer diagnosis, prognosis, or potential therapeutic targets. In this study, we aimed to explore whether the circulation lncRNA could predict the tumorigenesis of surgical squamous cervical cancer (CC). Methods: In this study, we applied the lncRNA microarray to screen the potential biomarker for CC. Real-time quantitate polymerase chain reaction was conducted for further validation in a larger sample size. The multi-stage validation and risk score formula analysis were used to examine the sensitivity and specificity. Results: We discovered 4 lncRNAs including HOTAIR, PVT1, XLOC_000303, and AL592284.1, which were upregulated in CC comparing with the cancer-free controls. Further, the receiver operating characteristic curve (ROC) analysis by risk score formula revealed the combined 4 factors with a high diagnostic ability with the area under ROC curve value of 0.875 and 0.958 in training set and validation set respectively. We finally confirmed the stable detection of the 4 lncRNAs by 5 cycles of freezing and thawing. Conclusion: HOTAIR, PVT1, XLOC_000303, and AL592284.1 might be the potential biomarkers for predicting the tumorigenesis of CC in the future.

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Aims: The aim of the study was to assess the effect of blocking TLR9 signaling on the proliferation of cervical cancer cells and its angiogenic property. Background: Toll-like receptors (TLRs) have been implicated for their crucial role in not only cervical cancer but also in other malignancies. TLR9 is expressed on an array of cells such as macrophages, dendritic cells, melanocytes, and keratinocytes. It is reported to modulate oncogenesis along with tumorigenesis by augmenting NF-κB mediated inflammation within the tumor environment. TLR9 has also been reported to positively regulate oncogenesis within the cervix and as a marker to evaluate malignant remodeling of cervical squamous cells. Therefore, this study was designed to explore the functional relevance of blocking the TLR9 signaling pathway in cervical cancer cells. Objective: The objective of the current study was to investigate the effect of human TLR9 antagonist, ODN INH-18, on apoptosis and cell cycle regulation and angiogenic property of human cervical cancer Caski cells. Method: MTT assay was performed to measure cell viability, and flow cytometry analysis was performed to assess cell cycle arrest. Quantitative real-time PCR (qRT-PCR) analysis was performed to measure fold change in the gene expression of various markers of apoptosis, cell cycle regulation, and angiogenesis. Result: The qRT-PCR results showed a higher expression level of TLR9 mRNA in Caski cervical cancer cells as compared to normal cervical keratinocytes. The apoptotic, angiogenic, and cell cycle regulatory factors were also deregulated in Caski cells in comparison to normal keratinocytes. The MTT assay demonstrated that treatment of TLR9 antagonist, ODN INH18, significantly reduced the proliferation of Caski cells in a dose-dependent manner. Treatment of ODN INH18 led to substantial cell cycle arrest in Caski cells at G0/G1 phase. Moreover, the qRT-PCR results demonstrated that ODN INH18 treatment led to suppressed mRNA expression of Bcl-2 and enhanced expression of Bax, signifying induction of apoptosis in Caski cells. Moreover, the expression of cyclin D1, Cdk4, and Cdc25A was found to be reduced, whereas expression of p27 was increased in ODN INH18-treated Caski cells, indicating G0/G1 phase arrest. Interestingly, expression of VEGF and VCAM-1 were found to be significantly inhibited in ODN INH18-treated Caski cells, substantiating alleviation of angiogenic property of cervical cancer cells. Conclusion: The results of our study suggest that inhibiting TLR9 signaling might be an interesting therapeutic intervention for the treatment of cervical cancer.

Background: The relationship between Insulin-like growth factor 2 (IGF2) methylation in the P3 promoter region and birth outcomes in a hypobaric-hypoxia environment has never been investigated. This study examined the association and compared birth outcomes and IGF2 methylation in this region by ethnicity and altitude. Methods: Four hundred and six (406) mother and newborn pairs in the Tibetan Plateau were enrolled in a birth cohort study. Data were collected through interviews using structural questionnaires or extracted from medical records. Pyrosequencing was performed for IGF2 methylation in the P3 promoter region in maternal peripheral and umbilical cord blood. Birth outcomes and IGF2 methylation were compared among three groups: Han in high altitude (HHA, n=164, 2000-3500m), Tibetan in high altitude (THA, n=42, 2000-3500m), and Tibetan in ultra-high altitude (TUHA, n=200, 3500m and higher). Results: TUHA seemed to have a higher prevalence of macrosomia (7.5%) than both THA (0.0.%) and HHA (2.4%) and a lower IGF2 methylation level in maternal blood than THA (P=0.008). No difference in the IGF2 methylation levels was found between THA and HHA. The IGF2 methylation levels in maternal peripheral blood were associated with a reduced risk of macrosomia (RR= 0.726, 95% CL [0.528,0.998], P=0.049) among all mother and newborn pairs. Conclusions: Increased altitude appears to be associated with decreased maternal IGF2 methylation levels in the P3 promoter region, and maternal IGF2 methylation levels in this region was associated with reduced risk of macrosomia in newborns in the hypobaric hypoxic Tibetan Plateau environment. Keywords Macrosomia; IGF2; DNA methylation; high altitude; Tibet Plateau