Circulating RNA ZFR promotes hepatocellular carcinoma cell proliferation and epithelial-mesenchymal transition process through miR-624-3p/WEE1 axis

Frequent dysregulation of multiple circular RNA isoforms with diverse regulatory mechanisms in cancer - Insights from circFNDC3B and beyond: Why unique circular RNA identifiers matter

Circular RNAs (circRNAs) are post-transcriptional regulators generated through backsplicing of pre-mRNAs, primarily comprising exons of host genes. A single host gene may produce multiple circRNA isoforms with distinct structures and sequences. Dysregulated circRNA expression has been implicated in tumorigenesis. This review aims to investigate the selection and regulatory roles of circRNA isoforms in cancer using the extensively studied hsa_circFNDC3B and thirteen other circRNAs as study models. Interrogation of literature and databases, particularly the circBase, confirms that host genes generate a plethora of circRNA isoforms; however, only a small subset of isoforms is validated as dysregulated in tumor tissues. Notably, two or more isoforms of the same circRNA are frequently dysregulated in cancer. Structurally, short isoforms retaining 5'-proximal exons are preferentially selected, but for long host genes, circRNAs may arise from mid- or 3'-regions. We identify dysregulation of seven circFNDC3B isoforms across twelve cancer types and multi-isoforms in nine of the other thirteen circRNAs also in multiple cancers. MicroRNA sponging appears to be the major regulatory mechanism, but possible biased study designs raise concerns. Using circFNDC3B and circZFR as examples, we show inconsistency and inadequacy in circRNA nomenclature in different databases and the literature, underscoring the urgent need for a universally accepted standardized central circRNA database. As an interim measure, we propose guidelines for circRNA nomenclature in journal publications. Our findings caution against indiscriminate clinical use of specific circRNA isoforms as biomarkers or therapeutic targets without further validation.

Lactate promotes the epithelial-mesenchymal transition of liver cancer cells via TWIST1 lactylation

Elevated lactate levels increase the risk of liver cancer progression. However, the mechanisms by which lactate promotes liver cancer progression remain poorly understood. Epithelial-mesenchymal transition (EMT), characterized by the loss of epithelial cells polarity and cell-cell adhesion, leading to the acquisition of mesenchymal-like phenotypes, is widely recognized as a key contributor to liver cancer progression. TWIST1 (Twist Family BHLH Transcription Factor 1) plays a central role in inducing EMT. Here, we investigated the role of lactate in promoting EMT in liver cancer and the underlying regulatory mechanisms. High levels of lactate significantly promoted EMT progression in liver cancer cells. Mechanistically, lactate-induced lactylation of TWIST1 in vivo and in vitro. Mutation assay confirmed that Lysine 33 (K33) is the major site of TWIST1 lactylation. Moreover, cell fractionation & luciferase reporter assay results identified that TWIST1-K33R mutant impaired the EMT process via inhibiting nuclear import and the transcriptional activity. Thus, our findings provide novel insights into the regulatory role of lactate in EMT in liver cancer pathogenesis. Additionally, targeting of lactate-driven lactylation of TWIST1 may boost the therapeutic strategy for liver cancer.

COLEC10: A potential tumor suppressor and prognostic biomarker in hepatocellular carcinoma through modulation of EMT and PI3K-AKT pathways

Hepatocellular carcinoma (HCC) is a cancer with poor prognosis, underscoring the urgent need for enhanced detection and management. This study aimed to investigate the role of Collectin Subfamily Member 10 (COLEC10) in HCC, which was revealed to be associated with various diseases. Bioinformatics tools, including GEO, cBioPortal, and TCGA, were used to identify differentially expressed genes. The prognostic significance of COLEC10 was assessed in two patient cohorts, and its functional impact on Hep3B and SMMC7721 cells was evaluated through CCK-8 and Transwell assays. The underlying mechanisms of COLEC10 in HCC progression were explored using flow cytometry and western blot. COLEC10 was downregulated in HCC and associated with poorer overall survival and disease progression. The potential interaction of COLEC10, CCBE1, and FCN3 was predicted. COLEC10, CCBE1, and FCN3 were identified as prognostic indicators for HCC. Overexpression of COLEC10 inhibited the proliferation, migration, and invasion of HCC cells. COLEC10 overexpression induced G0/G1 cell cycle arrest and suppressed epithelial-mesenchymal transition (EMT), COLEC10 regulated protein expression in the Hedgehog pathway and phosphorylation of key proteins in the PI3K-AKT pathway. COLEC10 is an independent prognostic factor of HCC. COLEC10 regulates EMT, Hedgehog, and PI3K-AKT pathways, providing new ideas for targeted therapy of HCC.

MYBBP1A‑mediated IGFBP4 promoter methylation promotes epithelial‑mesenchymal transition and metastasis through activation of NOTCH pathway in liver cancer

Metastatic hepatocellular carcinoma (HCC) seriously threatens patients' prognosis. It was previously suggested that the insulin growth factor binding protein (IGFBP) family could serve as cancer suppressors in the development and metastasis of HCC. However, the role of IGFBP4 and its underlying molecular mechanism in HCC metastasis is elusive. In the present study, it was found that IGFBP4 is significantly downregulated in HCC, whose expression is positively correlated with the prognosis of patients with HCC. Overexpression of IGFBP4 restrained migration abilities and cancer metastasis of HCC cells both in vitro and in vivo. Furthermore, it was found that IGFBP4 represses HCC metastasis by inhibiting epithelial‑mesenchymal transition. Molecular mechanism studies showed that overexpression of IGFBP4 obviously suppresses NOTCH1 signaling in HCC. As for the upstream regulatory mechanism, it was revealed that downregulation of IGFBP4 in HCC was caused by CpG islands' hyper‑methylation‑dependent degradation mediated by MYBBP1A. Inhibition of MYBBP1A limited HCC metastatic ability and silence of IGFBP4 at the same time restored HCC metastatic potentials. Clinical data demonstrated that low expression of IGFBP4 was found in patients with HCC, especially with lymphatic metastasis. High MYBBP1A expression and low IGFBP4 expression in HCC were correlated with poor survival of patients with HCC. Summarily, in the present study, it was revealed that MYBBP1A/IGFBP4/NOTCH1 pathway could play a crucial role in the progression and metastasis of HCC, which stimulates novel therapeutic and diagnostic strategies against metastatic HCC.

Farrerol suppresses epithelial-mesenchymal transition in hepatocellular carcinoma via suppression of TGF-β1/Smad2/3 signaling

BACKGROUND

Epithelial-mesenchymal transition (EMT) is an essential process for the metastasis of multiple malignancies, including hepatocellular carcinoma (HCC). Farrerol is a plant-derived flavonoid and has significant pharmacological effects. However, the anticancer activities of farrerol have not been fully elucidated. Here, we investigated the effects of farrerol on HCC progression.

METHODS

The potential of farrerol to prevent HCC cell migration and invasiveness was evaluated by wound healing and transwll matrix assays. Immunoblotting, immunofluorescence, and qPCR were used to detect the levels of EMT-related proteins. Transforming growth factor beta (TGF-β) (10 ng/ml) was used to stimulate HCC cells, followed by measurement of cell migration, invasiveness, and the EMT. TGF-β1/Smads signaling was examined by immunoblotting. A xenograft mouse model was used to assess the anticancer efficacy of farrerol in vivo. The expression levels of EMT- and angiogenesis-related proteins in xenograft tumors were evaluated by immunoblotting or immunohistochemistry.

RESULTS

We found that farrerol blocked HCC cell migration and invasiveness. Farrerol upregulated E-cadherin levels and reduced N-cadherin and vimentin levels. Farrerol also downreuglated the expression levels of EMT-related transcription factors including slug, snail, twist, and zeb1. Furthermore, farrerol suppressed TGF-β-stimulated migration, invasiveness, and the EMT in HCC cells. The phosphorylation of Smad 2/3 induced by TGF-β was inhibited by farrerol. Importantly, farrerol suppressed HCC growth and the EMT in vivo. Farrerol also inhibited tumor angiogenesis by inhibiting hypoxia-inducible factor-1 alpha (HIF-1α) and vascular endothelial growth factor (VEGF) in vivo.

CONCLUSION

Overall, farrerol suppresss HCC by inhibiting migration, invasiveness, the EMT, and angiogenesis, implying that farrerol could be a promising antimetastasis agent for HCC.

Circ_0000069 promotes the development of hepatocellular carcinoma by regulating CCL25

BACKGROUND

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related deaths globally, influenced by aberrant circRNA expression. Investigating circRNA-miRNA-mRNA interactions can unveil underlying mechanisms of HCC and identify potential therapeutic targets.

METHODS

In this study, we conducted differential analyses of mRNAs, miRNAs, and circRNAs, and established their relationships using various databases such as miRanda, miRDB, and miTarBase. Additionally, functional enrichment and immune infiltration analyses were performed to evaluate the roles of key genes. We also conducted qPCR assays and western blotting (WB) to examine the expression levels of circRNA, CCL25, and MAP2K1 in both HCC cells and clinical samples. Furthermore, we utilized overexpression and knockdown techniques for circ_0000069 and conducted wound healing, transwell invasion assays, and a tumorigenesis experiment to assess the migratory and invasive abilities of HCC cells.

RESULTS

Our findings revealed significant differential expression of 612 upregulated genes and 1173 downregulated genes in HCC samples compared to normal liver tissue. Additionally, 429 upregulated circRNAs and 453 downregulated circRNAs were identified. Significantly, circ_0000069 exhibited upregulation in HCC tissues and cell lines. The overexpression of circ_0000069 notably increased the invasion and migration capacity of Huh7 cells, whereas the downregulation of circ_0000069 reduced this capability in HepG2 cells. Furthermore, this effect was counteracted by CCL25 silencing or overexpression, separately. Animal studies further confirmed that the overexpression of hsa_circ_0000069 facilitated tumor growth in xenografted nude mice, while the inhibition of CCL25 attenuated this effect.

CONCLUSION

Circ_0000069 appears to promote HCC progression by regulating CCL25, suggesting that both circ_0000069 and CCL25 can serve as potential therapeutic targets.

The three-dimensional culture of L929 and C2C12 cells based on SPI-SA interpenetrating network hydrogel scaffold with excellent mechanical properties

Cell-cultured meat, which is obtained by adsorbing cells on the three-dimensional scaffold, is considered a potential solution to animal welfare issues. Edible and safe cell-cultured meat scaffolds are a key part of its research. Soy protein isolate (SPI) hydrogel has a three-dimensional network structure and has been studied for L929 cell culture because of its non-toxicity and biocompatibility. However, the toughness and mechanical properties of SPI hydrogel are not enough to bear the requirements of cell cultivation. In this paper, sodium alginate (SA) was added to SPI hydrogel, and the interpenetrating network (IPN) technology was used to construct SPI-SA IPN hydrogel by transglutaminase and Ca2+ double crosslinking method. SPI-SA IPN hydrogel has excellent mechanical properties, structural stability and biodegradable performance than SPI hydrogel. The bio-compatibility and degradability of L929 and C2C12 cells on SPI-SA IPN hydrogel were studied by cytotoxicity, trypan blue and living/dead cell staining, and the growth law of the hydrogel as a scaffold for cell culture was analyzed. The results showed that L929/C2C12 cells can proliferate normally and adhere in hydrogel and have good bio-compatibility. L929 cells with size about 20-50 µm have better adhesion and growth abilities on SPI-SA IPN hydrogel than C2C12 cells with 100-300 µm. Therefore, the SPI-SA IPN hydrogel is non-toxic and supports the growth of cells in the pores of the material. This study provides a reference for the application of SPI-SA IPN hydrogels in vitro cell growth.