Circ-ZEB1 promotes PIK3CA expression by silencing miR-199a-3p and affects the proliferation and apoptosis of hepatocellular carcinoma

Abstract

Background Although the prognostic outcomes of liver cancer (LC) cases have improved with the advancement in diagnostic technology and treatment methods, the transferability and recurrence of HCC and the 5-year and 10-year survival rates of patients have remained unsatisfactory. As a result, there is a need for more accurate diagnostic indicators that can detect liver cancer early, effectively improving the prognosis of patients. Whole-genome sequencing (WGS) revealed that circ-ZEB1 and PIK3CA are highly expressed in HCC tissues, whereas miR-199a-3p is significantly downregulated in HCC. Multiple databases search and biological analysis revealed that elevated expression of circ-ZEB1 and PIK3CA was related to poor prognosis of HCC. In vitro and in vivo studies revealed that upregulated levels of PIK3CA and circ-ZEB1 were closely associated with HCC proliferation and apoptosis. Based on these results, we believe that circ-ZEB1 and PIK3CA could be used as biomarkers to diagnose and treat patients with HCC. More importantly, circ-ZEB1 can promotes the expression of PIK3CA by silencing miR-199a-3p and affecting the progression of HCC. Methods and results Postoperative specimens from 56 patients with HCC who had not undergone chemotherapy from 2015 to 2018 were collected from the Department of Hepatobiliary Surgery, Second Affiliated Hospital of Nanchang University. WGS revealed differential expression of genes in HCC. Furthermore, RT-qPCR detected the expression of circ-ZEB1, miR-199a-3p, and PIK3CA in HCC tissues. MTT, EdU, and plate cloning experiments were conducted to detect cell proliferation, whereas flow cytometry analysis was used to detect apoptosis. FISH was used to co-localize circ-ZEB1 and miR-199a-3p, and biotin-coupled probe pull-down assay was used to detect the specific binding of circ-ZEB1 and miR-199a-3p. The dual-luciferase report assay detected the association of miR-199a-3p with PIK3CA. Western blotting was used to study the expression of PIK3CA protein. Circ-ZEB1 and PIK3CA were upregulated in HCC and predicted a poor prognosis. MiR-199a-3p showed low expression in HCC, whereas downregulation of circ-ZEB1 reduced HCC cell proliferation and promoted cell apoptosis. MiR-199a-3p blocked the effect of circ-ZEB1 on HCC. Circ-ZEB1 served as a biomarker of HCC. Circ-ZEB1 promoted the expression of PIK3CA by silencing miR-199a-3p to affect the progress of HCC. Conclusions Circ-ZEB1 promoted the expression of PIK3CA by depleting miR-199a-3p, thereby affecting HCC proliferation and apoptosis.

Hsa_circ_0021727 (circ-CD44) promotes ESCC progression by targeting miR-23b-5p to activate the TAB1/NFκB pathway

“…Studies have shown that circRNAs might have a base sequence that binds to miRNAs, thereby act as a ceRNA to competitively bind to miRNAs, relieving the inhibitory effect of the miRNAs on their target genes, which then affects the occurrence and development of tumors [ 53 ]. Circ-ZEB1 promotes phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) expression by sponging miR-199a-3p, which affects the proliferation and apoptosis of hepatocellular carcinoma [ 54 ]. Our previous experiments found that hsa_circ_0021727 could act as a sponge for miR-23b-5p.…”

Circular RNAs regulate parental gene expression: A new direction for molecular oncology research

“…For example, upregulated circ-AKT1 could promote its parental gene AKT1 (v-akt murine thymoma viral oncogene homolog 1) expression by acting as miR-942-5p molecular sponge to suppress ovarian cancer tumor cells proliferation and migration ( 20 ). The apoptosis and cell cycle of tumor cell played important roles in tumor growth ( 62 ), recent studies had found that circFBLIM1 could function as a ceRNA to upregulate host gene FBLIM1 expression through sponging miR-346 and thus exert inhibitory effect in tumor cells apoptosis in hepatocellular cancer; circ-MAPK4 silencing had also been confirmed to downregulate its parental gene expression through ceRNA mechanism, resulting in upregulated phosphorylation level of P38/MAPK (mitogen-activated protein kinase) in glioma tumor cells and promoting tumor cells apoptosis ( 21 , 22 ). In addition, circ-VANGL1 knockdown was also found to prevent tumor cell cycle progression, resulting in more cells blocked at the G0/G1 stage ( 23 ).…”

Comprehensive Analysis of Differentially Expressed Circular RNAs in Keloid Dermal Tissues

“…To preliminarily analyze the molecular mechanisms by which dysregulated circRNAs could engage in keloid formation, we focused on ceRNA networks, where circRNAs can sponge miRNAs to regulate the expression of genes that is key to the pathogenesis of cancer or keloids [5,10]. By means of ENCORI databases, we found 251 miRNAs, each of which was predicted to bind with both one DEC and one DEG.…”