CircKIF4A enhances osteosarcoma proliferation and metastasis by sponging MiR-515-5p and upregulating SLC7A11.

BACKGROUND: Circular RNAs (circRNAs) are forms of non-coding RNAs that have crucial roles in regulation of various biological processes of several malignant tumors. circKIF4A is closely associated with malignant progression of a variety of cancers. However, the molecular mechanisms as well as roles of circKIF4A in osteosarcoma (OS) have not yet been clearly elucidated. METHODS: We evaluated the expression of circKIF4A in OS. Colony-formation, cell counting kit-8 (CCK-8), transwell and mice metastasis model assays were done to explore the roles of circKIF4A in vitro and in vivo. TargetScan database, double luciferase, quantitative reverse transcription polymerase chain reaction analysis (RT-qPCR), and RNA immunoprecipitation (RIP) were done to investigate the associated molecular mechanisms. RESULTS: In both OS cells and tissues, circKIF4A (hsa_circ_0007255) was found to be upregulated. In vitro and in vivo, circKIF4A knockdown markedly suppressed OS proliferation as well as metastasis. circKIF4A enhanced OS growth as well as metastasis by sponging miR-515-5p and by upregulating SLC7A11. CONCLUSIONS: We identified the biological significance of the circKIF4A-miR-515-5p-SLC7A11 axis in OS cell proliferation and metastasis, which is important in OS monitoring and treatment. More studies on circKIF4A will inform on the diagnostic markers for early OS screening.

circKIF4A promotes tumorogenesis of glioma by targeting miR-139-3p to activate Wnt5a signaling.

BACKGROUND: Glioma has the characteristics of high incidence and mortality, and is a common malignant tumor of the central nervous system. Circular RNAs (circRNAs) have been reported to play vital roles in progression of cancer including glioma, and circKIF4A is up-regulated in glioma tissues. However, its role and mechanisms in gliomas are unclear. METHODS: circKIF4A and miR-139-3p were determined by qRT-PCR. Transwell assay, wound-healing assay, cell colony formation and flow cytometry were performed to measure cell invasion, migration, proliferation and apoptosis. Western blotting was used to evaluate Wnt/ß-catenin pathway-related protein. Luciferase reporter assays confirmed the relationship among circKIF4A, miR-139-3p and Wnt5a. Sphere formation was performed to measure the ability of glioma-initiating cells (GICs) spheroid formation. A nude mouse xenograft model was established and immunohistochemical staining was used to detect Ki-67 and Wnt5a levels. RESULTS: circKIF4A and Wnt5a were up-regulated and miR-139-3p was down-regulated in both glioma cells and tissues. circKIF4A promoted Wnt5a expression by sponging miR-139-3p. Knockdown of circKIF4A inhibited the colony formation ability, migration and invasion, and promoted the apoptosis of glioma cells by regulating miR-139-3p. Knockdown of circKIF4A inhibited Wnt/ß-catenin signaling pathway and proliferation-related signal via miR-139-3p. Furthermore, knockdown of circKIF4A or overexpression of miR-139 suppressed the ability of sphere formation of GICs and inhibitd Wnt/ß-catenin signaling pathway and proliferation-related signal in GICs. Additionally, depletion of circKIF4A decreased the expression level of Wnt5a and Ki-67, inhibited tumorigenesis in xenograft modes. CONCLUSION: circKIF4A was overexpressed in glioma, and knockdown of circKIF4A suppressed glioma progression via miR-139-3p/Wnt5a axis. The results indicated that circKIF4A may be a potential target for clinical treatment of glioma.

A novel axis of circKIF4A-miR-637-STAT3 promotes brain metastasis in triple-negative breast cancer.

Among patients with triple-negative breast cancer (TNBC), distant metastasis is the leading cause of death. Our previous studies have shown that TNBC progression is greatly facilitated by circKIF4A, but uncertainty remains regarding its role in TNBC brain metastasis and the molecular mechanism. In this study, we found notable upregulation of circKIF4A in TNBC cell lines and brain metastases. Inhibition of circKIF4A impaired the ability of TNBC to proliferate, migrate, and cause brain metastasis. Luciferase reporter assays confirmed that circKIF4A competed for binding to miR-637 with STAT3 3' UTR. Western blot analysis revealed that inhibition of circKIF4A decreased STAT3 and p62 expression, while increased the LC3B-II/LC3B-I ratio and the expression of Beclin, indicating that downregulation of circKIF4A induced autophagy by competing with STAT3 for binding to miR-637. By employing a competitive endogenous RNA (ceRNA) mechanism, the circKIF4A-miR-637-STAT3 axis coordinates brain metastasis in TNBC. circKIF4A can therefore be used as a prognostic biomarker for brain metastasis in TNBC and as a therapeutic target.

CircKIF4A combines EIF4A3 to stabilize SDC1 expression to activate c-src/FAK and promotes TNBC progression.

Triple-negative breast cancer (TNBC) is recognized for its poor prognosis and limited options for treatment. Circular RNA KIF4A (circKIF4A) was documented to be abnormally overexpressed in TNBC and was correlated with a poor survival rate. The objective of this study is to further examine the functional role of circKIF4A and its underlying mechanism. CircKIF4A was significantly upregulated in TNBC and the knockdown of circKIF4A suppressed TNBC cell proliferation, migration, and invasion. CircKIF4A was directly bound to EIF4A3, which interacted with SDC1. Knockdown of circKIF4A reduced interaction between EIF4A3 and SDC1 as well as SDC1 mRNA stability. SDC1 activated the c-src/FAK signaling pathways and finally promoted TNBC progression. circKIF4A induced TNBC progress in the in vivo mouse model via SDC1. CircKIF4A interacts with EIF4A3 to stabilize SDC1 mRNA, which activates the c-src/FAK signaling pathways and promotes TNBC progression. This may provide a potential therapy for TNBC treatment.

CircKIF4A Is a Prognostic Factor and Modulator of Natural Killer/T-Cell Lymphoma Progression.

Background: Natural killer/T-cell lymphoma (NKTL) is difficult to treat. Circular RNAs (circ RNAs) have been implicated in tumorigenesis. However, the function of circKIF4A in NKTL has not been investigated. Methods: QPCR analysis was used to compare circKIF4A levels in NKTL cell lines versus normal cell lines. Kaplan-Meier survival analysis was used to assess the effect of circKIF4A on the prognosis of NKTL. The correlation between clinicopathological features and circKIF4A expression was examined using cox regression analysis. Luciferase reporter, RNA immunoprecipitation and immunohistochemistry assays were also used to investigate the mechanisms of circKIF4A in NKTL. Results: Our analyses revealed that circKIF4A is significantly upregulated in NKTL cell lines and that its upregulation correlates with the poor prognosis of NKTL. The silencing of circKIF4A significantly suppressed glucose uptake and lactate production in NKTL cells. Moreover, we showed that circKIF4A, PDK1, and BCL11A bind miR-1231 and that circKIF4A regulates PDK1 and BCL11A expressions by sponging miR-1231. Conclusions: During NKTL progression, circKIF4A regulated PDK1 and BCL11A levels by sponging miR-1231. Our data indicated that circKIF4A is oncogenic in NKTL and that it is a predictor of poor prognosis of NKTL.

CircKIF4A promotes non-small cell lung cancer proliferation and metastasis through MiR-1238/CLDN14 axis.

As the leading cause of cancer-related death worldwide, non-small-cell lung cancer (NSCLC) is still in need of improved therapeutic strategies. CircKIF4A has been found to be involved in the progression of multiple cancers while its role in NSCLC remains unclear. To investigate the functions of circKIF4A, we assessed the expression of circKIF4A in NSCLC cells and tissues and performed experiments to determine the detailed functions of circKIF4A in NSCLC, including migration and proliferation. We found CircKIF4A expressed more heavily in the cells and tissues of NSCLC patients, and functional studies showed that inhibition of circKIF4A reduced NSCLC cells metastasis and proliferation. Furthermore, we seek to identify the underlying regulatory effect of circKIF4A in NSCLC. Studies revealed that circKIF4A sponged miR-1238 to promote NSCLC progression by up-regulating claudin14 (CLDN14) expression. In conclusion, circKIF4A is a potential diagnostic and therapeutic target in the circKIF4A/miR-1238/CLDN14 axis that plays an important role in NSCLC progression.

Circular RNA circKIF4A facilitates the malignant progression and suppresses ferroptosis by sponging miR-1231 and upregulating GPX4 in papillary thyroid cancer.

Circular RNAs (circRNAs) are one type of non-coding RNA. They act as important role in regulating various biological processes in the malignant progression. But we don't clearly know the specific mechanism of the majority circRNAs in papillary thyroid tumor progression. In the current study, we explored circKIF4A and the result showed that it had high expression in papillary thyroid cancer. The functions of circKIF4A were explored by CCK-8, transwell, and mouse xenograft experiments. Knockdown of circKIF4A could suppress papillary thyroid cell growth and migration. In addition, RIP assays and dual luciferase vector reporter assays were further conducted. Our consequence showed circKIF4A facilitated the malignant progress of papillary thyroid tumor by sponging miR-1231 and upregulating GPX4 expression. In conclusion, our study proved that circKIF4A-miR-1231-GPX4 axis played a vital role in cancer proliferation and ferroptosis by competing endogenous RNAs. Therefore, targeting circKIF4A is very likely to be a potential method for treatment of papillary thyroid cancer in the future.

circKIF4A sponges miR-127 to promote ovarian cancer progression.

Ovarian cancer is a major gynecologic cancer and common cause of gynecologic cancer death worldwide. However, the molecular mechanisms of ovarian cancer progression are still unclear. circular RNAs (circRNAs) are recently reported to be involved in cancer progression regulation but the potential functions of circRNAs in ovarian cancer remains unknown. In this study, we explored the expression of circKIF4A in ovarian cancer tissues. Then, a series of experiments were conducted to investigate how circKIF4A functioned in ovarian cancer in vitro and in vivo. The results revealed that circKIF4A was highly expressed in ovarian cancer tissues. Knockdown of circKIF4A suppressed cell proliferation and migration in ovarian cancer. Subsequent mechanism study revealed that circKIF4A acted as a competitive endogenous RNA (ceRNA) to promoted ovarian cancer progression by sponging miR-127 and upregulated the expression of Junctional adhesion molecule 3 (JAM3). Therefore, circKIF4A could be a novel biomarker and therapeutic target for ovarian cancer.

Circular RNA KIF4A promotes cell migration, invasion and inhibits apoptosis through miR-152/ZEB1 axis in breast cancer.

BACKGROUND: Circular RNAs (circRNAs) have been demonstrated to exert crucial mediators in tumor initiation and development. Nevertheless, the roles of circKIF4A in breast cancer (BC) are still not very clear. METHODS: Quantitative real-time polymerase chain reaction (qRT-PCR) was conducted to determine the expression of circKIF4A, miR-152, zinc finger E-box binding homeobox 1 (ZEB1) mRNA and caspase-3. Western blot assay was utilized to examine the protein level of ZEB1. Transwell assay and flow-cytometric analysis were adopted for the evaluation of cell migration, invasion and apoptosis, respectively. The associations among circKIF4A, miR-152 and ZEB1 were predicted by online websites and verified by dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay. RESULTS: CircKIF4A and ZEB1 were conspicuously upregulated and miR-152 was markedly reduced in BC tissues and cells. Deficiency of circKIF4A repressed migration, invasion and induced apoptosis of BC cells. Moreover, circKIF4A was confirmed to be a sponge of miR-152 and miR-152 could bind to ZEB1. MiR-152 inhibition or ZEB1 overexpression abolished the impacts of circKIF4A knockdown on cell migration, invasion and apoptosis in BC. CONCLUSION: Silencing of circKIF4A hampered cell metastasis and promoted apoptosis by regulating ZEB1 via sponging miR-152 in BC.

Circular RNA circKIF4A Sponges miR-375/1231 to Promote Bladder Cancer Progression by Upregulating NOTCH2 Expression.

Circular RNAs (circRNAs) have been found to be important mediators of many biological processes in the growth and metastasis of various cancers. However, the potential roles of most circRNAs in the progression of bladder cancer remain unclear. In this research, we investigate the role of circKIF4A (hsa_circ_0007255) in the development and progression of bladder cancer. Detected by qRT-PCR analysis, circKIF4A was significantly upregulated in bladder cancer tissues and cell lines. We conducted CCK-8, colony-formation, transwell and mouse xenograft assays to explore the function of circKIF4A in bladder cancer. Functionally, knockdown of circKIF4A inhibited the proliferation and colony-formation ability of bladder cancer cells. Migration and metastatic ability were dramatically decreased after transfection with small interfering RNA targeting circKIF4A in both in vitro and in vivo assays. Mechanically, luciferase reporter assays and RNA immunoprecipitation assays were carried out to elucidate the underlying molecular mechanism of circKIF4A. The results revealed that circKIF4A sponges miR-375/1231 to promote bladder cancer progression by upregulating NOTCH2. Generally, our research unveils the essential role of circKIF4A-miR-375/1231-NOTCH2 axis in bladder cancer progression possibly via the competing endogenous RNA mechanism.

Relationship between circKIF4A expression and clinicopathologic features and prognosis of thyroid cancer patients / 国际检验医学杂志

Objective To investigate the relationship between circKIF4A expression and clinicopathologic features and prognosis of thyroid cancer patients.Methods A total of 120 patients diagnosed with thyroid cancer in our hospital from April 2016 to April 2017 were selected by random sampling method.Cancer tissues and adjacent tissues were taken during surgery and divided into thyroid cancer group and adjacent cancer group according to surgical pathologic detection.The relative expression level of circKIF4A in thyroid cancer group and paracancer group was detected by qRT-PCR,and the relationship between circKIF4A expression and clini-copathological features of thyroid cancer was analyzed.Kaplan-Meier survival curve was used to analyze the relationship between circKIF4A expression and prognosis of thyroid cancer patients.Cox regression analysis was performed to analyze the factors influencing the poor prognosis of patients with thyroid cancer 5 years af-ter surgery.Results The relative expression level of circKIF4A in thyroid cancer group was higher than that in paracancer group,and the difference was statistically significant(P＜0.05).The expression of circKIF4A was correlated with the degree of capsule invasion,lymph node metastasis and differentiation(P＜0.05).Kap-lan-Meier survival curve analysis showed that the 5-year cumulative survival rate of patients with high cir-cKIF4A expression was lower than those with low circKIF4A expression,and the difference was statistically significant(x2=11.368,P=0.001).Multivariate analysis showed that envelope invasion,degree of differenti-ation,lymph node metastasis and circKIF4A expression level were the influencing factors for poor prognosis of thyroid cancer patients at 5 years after surgery(P＜0.05).Conclusion circKIF4A is highly expressed in thy-roid cancer tissues,which is related to the clinicopathological features and 5-year postoperative survival of thy-roid cancer patients,and may be used as a potential prognostic marker for thyroid cancer.