Downregulation of hepatic lipase is associated with decreased CD133 expression and clone formation in HepG2 cells

CircRNA CDR1as promotes hepatoblastoma proliferation and stemness by acting as a miR-7-5p sponge to upregulate KLF4 expression

Hepatoblastoma (HB) is a malignant embryonal tumor of the liver that consists of heterogenous populations of stem/progenitor cells. Although circular RNAs (circRNAs) play an essential role in tumor development, the effects of circRNA on the proliferation of HB cells, especially cancer stem cells (CSCs), remain unclear. We found that the circRNA, CDR1as, was highly expressed in CSC-enriched populations of HB cell lines. Results from flow cytometric and sphere-forming assays revealed that CDR1as knockdown in HB cell lines decreased the proportion of stem cells. The Cell Counting Kit-8 (CCK-8) assay, colony formation experiments, and EdU assay revealed that CDR1as knockdown in HB cell lines decreased cell growth and the colony-forming abilities. Biotin-coupled probe pull-down assays and biotin-coupled microRNA capture were conducted to evaluate the interaction between CDR1as and miR-7-5p. Dual-luciferase reporter assays demonstrated that Kruppel-like factor 4 (KLF4), expression of which is highly correlated with cancer stemness, was a target of miR-7-5p. Overall, the knockdown of CDR1as significantly inhibited the proliferation and stemness of HB cells by reducing the sponge activity on miR-7-5p and subsequently suppressing the interaction between miR-7-5p and KLF4. Results from this study suggest that CDR1as is an oncogene that effects the proliferation and stemness of HBs.

LIPH promotes metastasis by enriching stem-like cells in triple-negative breast cancer

Lipase member H (LIPH), a novel member of the triglyceride lipase family. The clinical implications of its expression in breast cancer are still unclear. Therefore, in this study, we investigated the associations between LIPH and the tumorigenic behaviours of 144 triple-negative breast cancer (TNBC) patients. The ratio and mammosphere-forming ability of CD44+/CD24- stem-like cells were tested. The role of LIPH in breast cancer cell migration and invasion was also evaluated. In addition, the effect of LIPH silencing on mitochondrial respiration was determined using the Seahorse assay. Finally, the effect of LIPH silencing on protein expression was determined via tandem mass tag-based spectrometry and Western blotting. We found that LIPH expression was associated with metastasis in lymph nodes and distant organs (P = 0.025), resulting in poor survival among breast cancer patients (P = 0.027). LIPH knockdown significantly decreased both the ratio of CD44+ /CD24- stem-like cells and their mammosphere-forming ability. LIPH silencing promoted apoptosis, arrested cell cycle in the G2/M phase, mitigated the oxidation-related oxygen consumption rate in the mitochondria, and reduced metabolism. LIPH inhibited adhesion between tumour cells and enhanced the epithelial-mesenchymal transition. Tandem mass spectrometric analysis presented 68 proteins were differentially expressed in LIPH-silenced cells and LIPH-mediated modulation of tumour cell adhesion depended on integrin-related CAPN2 and paxillin signalling. Overall, our findings provided strong evidence that LIPH up-regulation promoted metastasis and the stemness of TNBC cells. Therefore, targeting LIPH is a potentially viable strategy for preventing metastasis in TNBC.

The novel miR-1269b-regulated protein SVEP1 induces hepatocellular carcinoma proliferation and metastasis likely through the PI3K/Akt pathway

Decreased intercellular adhesion is a key step in the metastasis and recurrence of many cancers, including hepatocellular carcinoma (HCC). SVEP1 is an important cell adhesion molecule that plays a key role in regulating intercellular adhesion and embryonic lymphatic development. However, the expression patterns and roles of SVEP1 in HCC are still largely unknown. We identified SVEP1 expression by analyzing 220 HCC samples from our cancer center. TCGA and GEO online-databases were used for data calibration and validation. SVEP1 was differentially expressed in two groups of HCCs with different risks of recurrence and was deemed as an independent risk factor for the prognosis of HCC. The expression of SVEP1 is negatively related to the proliferation and metastasis of HCC. Downregulation of SVEP1 expression promoted in vitro HCC cell migration, chemotaxis, invasion and proliferation, as well as in vivo tumor growth, local invasion and metastasis in a mouse model. Bioinformatic analysis and RT-PCR results showed that miR-1269b expression is negatively correlated with the SVEP1 expression and the prognosis of HCC patients. Further experiments showed that miR-1269b directly targets and downregulates the expression of SVEP1, which further induces the phosphorylation of Akt at thr308. These regulatory effects ultimately mediate the proliferation and metastasis of HCC cells. SVEP1 could serve as a promising prognostic marker of HCC. MiR-1269b downregulates SVEP1 expression and promotes HCC proliferation and metastasis likely through the PI3k/Akt signaling pathway.