Circ-CCT2 Activates Wnt/ß-catenin Signaling to Facilitate Hepatoblastoma Development by Stabilizing PTBP1 mRNA.

BACKGROUND & AIMS: Circ-CCT2 (hsa_circ_0000418) is a novel circular RNA that stems from the CCT2 gene. However, the expression of circ-CCT2 and its roles in hepatoblastoma are unknown. Our study aims to study the circ-CCT2 roles in hepatoblastoma development. METHODS: Hepatoblastoma specimens were collected for examining the expression of circ-CCT2, TAF15, and PTBP1. CCK-8 and colony formation assays were applied for cell proliferation analysis. Migratory and invasive capacities were evaluated through wound healing and Transwell assays. The interaction between circ-CCT2, TAF15, and PTBP1 was validated by fluorescence in situ hybridization, RNA pull-down, and RNA immunoprecipitation. SKL2001 was used as an agonist of the Wnt/ß-catenin pathway. A subcutaneous mouse model of hepatoblastoma was established for examining the function of circ-CCT2 in hepatoblastoma in vivo. RESULTS: Circ-CCT2 was significantly up-regulated in hepatoblastoma. Overexpression of circ-CCT2 activated Wnt/ß-catenin signaling and promoted hepatoblastoma progression, whereas knockdown of circ-CCT2 exerted opposite effects. Moreover, both TAF15 and PTBP1 were up-regulated in hepatoblastoma tissues and cells. TAF15 was positively correlated with the expression of circ-CCT2 and PTBP1 in hepatoblastoma. Furthermore, circ-CCT2 recruited and up-regulated TAF15 protein to stabilize PTBP1 mRNA and trigger Wnt/ß-catenin signaling in hepatoblastoma. Overexpression of TAF15 or PTBP1 reversed knockdown of circ-CCT2-mediated suppression of hepatoblastoma progression. SKL2001-mediated activation of Wnt/ß-catenin signaling reversed the anti-tumor effects of silencing of circ-CCT2, TAF15, or PTBP1. CONCLUSIONS: Circ-CCT2 stabilizes PTBP1 mRNA and activates Wnt/ß-catenin signaling through recruiting and up-regulating TAF15 protein, thus promoting hepatoblastoma progression. Our findings deepen the understanding of hepatoblastoma pathogenesis and suggest potential therapeutic targets.

LncRNA OIP5-AS1 aggravates the stemness of hepatoblastoma through recruiting PTBP1 to increase the stability of ß-catenin.

BACKGROUND: Hepatoblastoma is a malignancy that occurs in the liver, most of which occur in children younger than 3 years old. It was reported that lncRNA OIP5-AS1 was up-regulated in hepatoblastoma, but the detailed mechanism by which OIP5-AS1 regulates hepatoblastoma development is unclear. METHODS: qRT-PCR, Western blotting, and immunofluorescence were used to examine levels of OIP5-AS1, PTBP1, ß-catenin or proliferation/stemness-related molecules. Colony formation, sphere formation, wound healing assay and transwell were applied to detect cell proliferation, stemness and invasion, respectively. RIP assay was used to investigate the interaction of OIP5-AS1/PTBP1 and PTBP1/CTNNB1. Finally, in vivo model was constructed to detect the function of OIP5-AS1 in hepatoblastoma. RESULTS: OIP5-AS1 was significantly up-regulated in hepatoblastoma cells. OIP5-AS1 silencing notably attenuated the stemness and invasion of hepatoblastoma cells. OIP5-AS1 bound with PTBP1, and silencing of OIP5-AS1 inhibited ß-catenin. Meanwhile, overexpression of PTBP1 or ß-catenin activation significantly reversed OIP5-AS1 silencing-inhibited hepatoblastoma cell proliferation and stemness. Moreover, ß-catenin was found to be the downstream target of PTBP1, and OIP5-AS1 activated ß-catenin signaling via promoting the binding between PTBP1 and ß-catenin to increase the mRNA stability of ß-catenin. Finally, OIP5-AS1 knockdown significantly alleviated the tumor growth of hepatoblastoma by repressing ß-catenin. CONCLUSION: OIP5-AS1 silencing inhibits the growth and stemness of hepatoblastoma through binding with PTBP1 to inhibit ß-catenin signaling pathway. OIP5-AS1 may be the potential target against hepatoblastoma.

circSLC8A1 sponges miR-671 to regulate breast cancer tumorigenesis via PTEN/PI3k/Akt pathway.

Breast cancer is the most frequently diagnosed and the leading cause of cancer-related deaths in women worldwide. However, the role of circSLC8A1 in breast cancer remains elusive. Herein, a cohort of 77 breast tumors and paired adjacent normal mammary tissues were collected. We demonstrated that circSLC8A1 was significantly down-regulated in breast cancer tissues and cell lines, of which expression was negatively correlated with clinical severity and dismal prognosis. Overexpression of circSLC8A1 suppressed cell proliferation, migration and invasion in vitro, and inhibited tumor growth in vivo. CircSLC8A1 directly targeted miR-671 to execute tumor suppressive activities via regulating PI3k/Akt signaling. Krüppel-like factor 16 (KLF16), a transcriptional activator of PTEN, was identified as a target of miR-671. Furthermore, circSLC8A1 could sponge miR-671 to suppress breast tumor growth via PTEN/PI3k/Akt signaling in vivo. In summary, circSLC8A1/miR-671 regulates breast cancer progression through PTEN/PI3k/Akt signaling, which may provide efficient therapeutic target for this devastating cancer.

lncRNA DUXAP8 Facilitates Multiple Malignant Phenotypes and Resistance to PARP Inhibitor in HCC via Upregulating FOXM1.

In this study, we examined the clinical significance and molecular mechanisms of a long non-coding RNA (lncRNA), double homeobox A pseudogene 8 (DUXAP8) in hepatocellular carcinoma (HCC). DUXAP8 expression was compared using quantitative real-time PCR in HCC versus adjacent tissues and in HCC cell lines versus normal hepatic epithelial cells. The correlations between DUXAP8 level and clinicopathological features were analyzed. Assays including MTT, colony-forming analysis, Transwell assay, western blot, xenograft formation, experimental metastasis, luciferase assay, RNA pull-down, and RNA immunoprecipitation were used to examine DUXAP8-induced malignant phenotypes, its regulation on forkhead box protein M1 (FOXM1), and the importance of FOXM1 in mediating DUXAP8 phenotypes. Our results showed that DUXAP8 was significantly upregulated in HCC tissues or cell lines associated with tumors of advanced grades, tumors that were positive for lymph node metastasis, and patients with poor overall survival. DUAXP8 was essential in maintaining multiple malignant phenotypes (including resistance to olaparib) both in vitro and in vivo. Mechanistically, DUXAP8 upregulated FOXM1 expression by sponging miR-485-5p and interacting with the RNA-binding protein Fused in Sarcoma (FUS). Functionally, FOXM1 essentially mediated the oncogenic phenotypes of DUXAP8. Collectively, DUXAP8 acts through two distinct mechanisms to upregulate FOXM1 and becomes a pleotropic oncogenic lncRNA in HCC.

Survival and analysis of prognostic factors for hepatoblastoma: based on SEER database.

BACKGROUND: The goal of this study is to assess the newest survival of hepatoblastoma (HB) and the risk factors which impacted on survival by using the Surveillance, Epidemiology and End Results (SEER) database, also calculate the incidence of HB in recent years. METHODS: We calculate age-adjusted incidence of HB by using SEER 21 registries. Age, sex, race, tumor size, macrovascular involvement, multifocal tumor, distant metastasis, the way of treatment, and the survival were collected for survival and analysis of prognostic factors in SEER 18 registries. Survival curves, according to different factors, were obtained by Kaplan-Meier estimates. Multivariable Cox regression models were also built. RESULTS: The overall age-adjusted incidence of HB was 0.19 patients per 100,000 children with a statistically significant increase per year. Overall survival (OS) at 1-, 3- and 5-year for all patients were 89.3%, 84.6%, and 81.9%, respectively. Multivariate analysis showed tumor size >5 cm [hazard ratio (HR), 8.271; 95% confidence interval (CI), 1.134-60.310], multiple tumors (HR, 2.578; 95% CI, 1.424-4.668) and no-surgery treatment (HR, 7.520; 95% CI, 4.121-13.724) were independent indicators of poor prognosis. Only the age ≥2-year-old (HR, 3.240; 95% CI, 1.433-7.326) and multiple tumors (HR, 2.395; 95% CI, 1.057-5.430) were the risk factors for the surgical treatment group. CONCLUSIONS: The survival of patients with HB has been greatly improved in the recent years, and at the same time, due to the application of better chemotherapy, we should re-evaluate the traditional risk indicators of prognosis in order to better apply to the clinical.

[X-linked inhibitor of apoptosis protein (XIAP) and Survivin suppression on human pancreatic cancer cells Panc-1 proliferation and chemosensitivety].

OBJECTIVE: To investigate the effect on cell proliferation and chemosensitivity of human pancreatic cancer cells Panc-1 after X-linked inhibitor of apoptosis protein (XIAP) and Survivin are inhibited simultaneously, and to compare it with the separate gene suppression strategy by which expression of XIAP or Survivin is inhibited respectively. METHODS: Panc-1 (Panc-1-X, Panc-1-S and Panc-1-XS) in which expression of XIAP and/or Survivin was inhibited, was established by using XIAP-shRNA lentiviral and Survivin-shRNA lentiviral we had built. The expressions of XIAP and Survivin mRNA and protein were evaluated by Real-time PCR and Semi-quantitatively Western blot analysis; cell proliferation was investigated by cell counting and colony formation assay; cell apoptosis was investigated by Caspase-3/7 activity assay kit and flow cytometry; gemcitabine (Gem) chemosensitivity was investigated by MTT assay. RESULTS: The pancreatic cell line Panc-1 in which the expression of XIAP and/or Survivin was stablely inhibited was successfully established. The cell proliferation of Panc-1-XS cells decreased significantly. The colony formation rate of Panc-1-XS cells (10.12%± 1.33%), was significantly lower than that of Panc-1-XncSnc cells (96.61% ± 7.89%) and Panc-1 cells (100.28% ± 8.97%) respectively (P<0.05). After being treated by 0.5 mg/L Gem for 24 h, the Caspase-3/7 relative activity of Panc-1-XS cells (15.02 ± 0.57) was significantly higher than that of Panc-1 cells and Panc-1-XncSnc cells (8.87 ± 0.19 and 9.05 ± 0.23, respectively; P<0.05); and the rate of apoptosis of Panc-1-XS cells (24.09% ± 2.75%) was significantly higher than that of Panc-1-XncSnc cells and Panc-1 cells (12.09% ± 1.97% and 12.06% ± 1.22%, respectively; P<0.05). The IC50 value of Panc-1-XS cells [(0.47 ± 0.04) mg/L] was significantly lower than that of Panc-1-XncSnc cells [(2.18 ± 0.13) mg/L] and Panc-1 cells [(2.13 ± 0.18) mg/L, P<0.05]. Further testing also showed that, the IC50 value of Panc-1-XS cells [(0.47 ± 0.04) mg/L] was significantly lower than that of Panc-1-X cells [(0.76 ± 0.07) mg/L] and Panc-1-S cells [(0.87 ± 0.09) mg/L, P<0.05]. CONCLUSION: The cell proliferation of Panc-1 cells was significantly suppressed and the Gem chemosensitivity was significantly enhanced after expressions of XIAP and Survivin were inhibited simultaneously, and significantly better than the strategy in which expressions of XIAP and Survivin were inhibited separately.