Although human papillomavirus (HPV) infection has been found in most of the cervical cancer cases, additional genetic and epigenetic changes are required for disease progression. Previously, it was thought that only genetic mutation plays a key role in cervical cancer development. But recent advances in the biology of cervical cancer revealed that epigenetic alteration is common in cervical carcinogenesis and metastasis. Epigenetic alteration due to aberrant DNA methylation and histone modification has been extensively studied in cervical cancer. Recent research strategies keep insight into noncoding RNAs, especially miRNA and lncRNA. At the same time, interest has been grown to study the utility of these changes as biomarkers to determine disease progression as well as use them as the therapeutic targets. This study has been aimed to review the recent progress of epigenetic study for cervical cancer research including role of these epigenetic changes in disease progression, their prognostic values, and their use in targeted therapy.

Background: Evidence has been shown that circular RNAs (circRNAs) play a vital role during the development of ovarian cancer. However, the mechanism by which circEXOC6B regulates tumorigenesis of ovarian cancer remains unknown. Thus, this study aimed to investigate the role of circEXOC6B during the progression of ovarian cancer. Materials and Methods: The dual-luciferase reporter system assay was used to determine the interaction between circEXOC6B, miR-421 and RUS1 in ovarian cancer, respectively. CCK8 and colony formatting were used to evaluate cell proliferation. Meanwhile, the expressions of RSU1, PINCH1 and ILK in SKOV3 cells were detected with Western blot. Results: Downregulation of circEXOC6B markedly promoted the proliferation and invasion in A2780 cells. In contrast, upregulation of circEXOC6B significantly inhibited the proliferation and invasion in SKOV3 cells. Moreover, overexpression of circEXOC6B obviously induced the apoptosis of SKOV3 cells. Furthermore, luciferase reporter assay identified that miR-421 was the potential miRNA binding of circEXOC6B, and RUS1 was the potential binding target of miR-421. Mechanism analysis indicated that upregulation of circEXOC6B increased the level of RUS1 by acting as a competitive "sponge" of miR-421. Conclusion: In this study, we found that circEXOC6B suppressed the growth of ovarian cancer cells through upregulating RSU1 partially via sponging miR-421. Therefore, circEXOC6B might be a potential target for the treatment of ovarian cancer.

Background: This work was designed to explore the roles of PIM-1 in the development of cervical cancer. Methods: There were 90 paired cervical tumor samples and the non-tumor adjacent tissue. The levels of PIM-1 in different samples were examined using quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) methods. The potential diagnostic value of PIM-1 was analyzed by the receiver operating characteristic (ROC) curve; furthermore, the expression of EGFR in tumor samples was detected, and Pearson’s correlation analysis was performed to analyze the relationship between the expression of PIM-1 and EGFR. Finally, cervical cancer cell line Hela cells were cultured and treated by PIM-1 siRNA, and MTT assay and Pi/Annexin V assay were performed to explore the effects of PIM-1 siRNA on the growth and apoptosis ability of the Hela cells. Results: PIM-1 was significantly up-regulated in cervical cancer tissue compared to adjacent tissue, and the expression of PIM-1 in patients with cervical cancer is positively associated with the size and metastasis of the tumor. ROC analysis showed PIM-1 is a sensitive biomarker for the diagnosis of cervical cancer. Furthermore, EGFR was over-expressed in cervical cancer tumor tissues, and the levels of PIM-1 and EGFR in cervical cancer tissue were positively correlated. Finally, PIM-1 siRNA dramatically inhibited the viability and promoted the apoptosis of the Hela cells. Conclusion: Our findings prove that PIM-1 may function as an oncogene in cervical cancer and can regulate the EGFR signaling in cervical cancer.

Natural fractures play an important role in the seepage system of Paleogene sandstone reservoirs at Nanpu Sag. Characteristics and formation mechanisms of natural fractures and stress-sensitivity permeability are comprehensively investigated and their impact on water injection is discussed based on core and log data (FMI and diplog data) as well as stress-sensitivity permeability measurement. Results show that high-angle shear fractures, including NE-SW strike fractures and NW-SE strike fractures, are widely developed in the study area, which were primarily developed during the late Paleogene and late Neogene. The present maximum horizontal principal stress is orientated at N60°–80°E, approximately parallel to the NE-SW fractures, contributing greatly to the seepage system at the early oilfield development stage. Fractures in the study area can be divided into three phases and are characterized by obvious stress-sensitivity permeability, which is closely related to fracture aperture and throat size. Since the fracture occurrence enhances stress sensitivity of permeability, it is necessary to regulate well pattern based on dynamic behaviors of fractured reservoirs at different development stages.