Hypoxia-induced circ-CDYL-EEF1A2 transcriptional complex drives lung metastasis of cancer stem cells from hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is often associated with poor outcomes due to lung metastasis. ICAM-1+ circulating tumor cells, termed circulating cancer stem cells (CCSCs), possess stem cell-like characteristics. However, it is still unexplored how their presence indicates lung metastasis tendency, and particularly, what mechanism drives their lung metastasis. Here, we demonstrated that a preoperative CCSC count in 5 mL of blood (CCSC5) of >3 was a risk factor for lung metastasis in clinical HCC patients. The CSCs overexpressed with circ-CDYL entered the bloodstream and developed lung metastases in mice. Mechanistically, circ-CDYL promoted COL14A1 expression and thus ERK signaling to facilitate epithelial-mesenchymal transition. Furthermore, we uncovered that an RNA-binding protein, EEF1A2, acted as a novel transcriptional (co-) factor to cooperate with circ-CDYL and initiate COL14A1 transcription. A high circ-CDYL level is caused by HIF-1⍺-mediated transcriptional upregulation of its parental gene CDYL and splicing factor EIF4A3 under a hypoxia microenvironment. Hence, the hypoxia microenvironment enables the high-tendency lung metastasis of ICAM-1+ CCSCs through the HIF-1⍺/circ-CDYL-EEF1A2/COL14A1 axis, potentially allowing clinicians to preoperatively detect ICAM-1+ CCSCs as a real-time biomarker for precisely deciding HCC treatment strategies.

Serum Ferritin in Geriatric Individuals in the Shanghai Region: Distribution, Correlations, and Reference Intervals.

BACKGROUND: Serum ferritin levels have a clinical application in diagnosing diseases. However, the clinical standard levels and distribution characteristics of serum ferritin based on reference intervals (RIs) in the geriatric Han Chinese population in the East China region have not previously been well reported. This work aimed to investigate the correlation between serum ferritin levels and 14 metabolic markers, analyse the distribution of serum ferritin, and establish serum ferritin RIs for geriatric (> 60 years) individuals in Shanghai. METHODS: Four hundred and sixty-nine healthy Chinese Han subjects (age, 61 - 95 years; median, 71 years) were recruited from the Health Examination Center of Shanghai Fourth People's Hospital in 2021. Serum ferritin was measured on a Roche Cobas 8000 e602, and 14 biochemical parameters were measured on a Siemens Atellica CH-930 to analyse distributions and correlations and to establish serum ferritin RIs for the elderly population in Shanghai. RESULTS: Serum ferritin levels were significantly different between genders (p = 0.06). The established RIs for serum ferritin were 24.44 - 627.09 ng/mL and 48.18 - 554.88 ng/mL in males and females, respectively. Correlation analyses revealed that ferritin levels were correlated with 7 parameters, including body mass index (BMI, p = 0.02), gamma-glutamyl transferase (GGT, p < 0.01), alanine aminotransferase (ALT, p < 0.01), triglycerides (TGs, p < 0.01), high-density lipoprotein (HDL, p < 0.01), total protein (TP, p < 0.01) and prealbumin (PAB, p < 0.01). When the participants were further divided by BMI, aspartate aminotransferase (AST) was an additional variable that was positively correlated only in the overweight/obese group (p = 0.04), while globulin (GLO) was an additional variable that was positively correlated only in the other group (p < 0.01). CONCLUSIONS: Nutrition and metabolism may play a great role in the regulation of serum ferritin levels in geriatric individuals in vivo. The RIs established for serum ferritin may provide precise references for further studies on ferritin-related disease in geriatric individuals.

Integrated analysis revealing the role of TET3-mediated MUC13 promoter hypomethylation in hepatocellular carcinogenesis.

Aim: To explore the function and underlying mechanism of MUC13 in hepatocellular carcinoma (HCC) oncogenesis. Materials & Methods: Online databases and software were used to perform analyses of expression, methylation and enrichment pathway. Experiments were performed to confirm the results using HCC cells in vitro. Results: MUC13 was upregulated in HCC and liver cancer stem cells (CSCs) and had a positive influence on CSC generation. Further analyses revealed that MUC13 with promoter hypomethylated was regulated by DNA demethylase TET3, which was overexpressed in HCC and liver CSCs. Conclusion: These results strongly suggested that high TET3 expression in liver CSCs may mediate MUC13 upregulation via promoter hypomethylation and thereby contribute to hepatocellular carcinogenesis.

To understand the function and mechanism of MUC13 in hepatocellular carcinogenesis, online databases and software were used to analyze MUC13 expression, promoter methylation and enrichment pathway. Experiments were also performed to further confirm the results in vitro. MUC13 was upregulated in hepatocellular carcinoma (HCC) and had a positive influence on cancer stem cell (CSC) generation. Further analyses revealed that MUC13 with promoter hypomethylated was regulated by DNA demethylase TET3, which was overexpressed in HCC and liver CSCs. Importantly, it was revealed that MUC13 with promoter hypomethylated, was regulated by TET3, which was overexpressed in HCC and liver CSCs. These results strongly suggest that high TET3 expression in liver CSCs may mediate promoter hypomethylation and expression upregulation of MUC13, thereby contributing to hepatocellular carcinogenesis.

Erratum: Circ-MALAT1 Functions as Both an mRNA Translation Brake and a microRNA Sponge to Promote Self-Renewal of Hepatocellular Cancer Stem Cells.

[This corrects the article DOI: 10.1002/advs.201900949.].

Methylation Status of the Nanog Promoter Determines the Switch between Cancer Cells and Cancer Stem Cells.

Cancer stem cells (CSCs) are the main cause of tumor development, metastasis, and relapse. CSCs are thus considered promising targets for cancer therapy. However, it is hard to eradicate CSCs due to their inherent plasticity and heterogeneity, and the underlying mechanism of the switch between non-CSCs and CSCs remains unclear. Here, it is shown that miR-135a combined with SMYD4 activates Nanog expression and induces the switch of non-CSCs into CSCs. The miR-135a level, once elevated, lowers the methylation level of the CG5 site in the Nanog promoter by directly targeting DNMT1. SMYD4 binds to the unmethylated Nanog promoter to activate Nanog expression in Nanog-negative tumor cells. The in vivo regulation of miR-135a levels could significantly affect both the CSCs proportion and tumor progression. These findings indicate that DNA methylation of the Nanog promoter modulates the switch of non-CSCs into CSCs under the control of the miRNA-135 level. In addition, the related pathways, miR-135a/DNMT1 and SMYD4, involved in these processes are potential targets for CSC-targeted therapy.

Circ-MALAT1 Functions as Both an mRNA Translation Brake and a microRNA Sponge to Promote Self-Renewal of Hepatocellular Cancer Stem Cells.

Both circular RNAs (circRNAs) and cancer stem cells (CSCs) are separately known to be involved in cancer, but their interaction remains unclear. Here, the regulation of hepatocellular CSC self-renewal is discovered by a circRNA, circ-MALAT1, which is produced by back-splicing of a long noncoding RNA, MALAT1. Circ-MALAT1 is highly expressed in CSCs from clinical hepatocellular carcinoma samples under the mediation of an RNA-binding protein, AUF1. Surprisingly, circMALAT1 functions as a brake in ribosomes to retard PAX5 mRNA translation and promote CSCs' self-renewal by forming an unprecedented ternary complex with both ribosomes and mRNA. The discovered braking mechanism of a circRNA, termed mRNA braking, along with its more traditional role of miRNA sponging, uncovers a dual-faceted pattern of circRNA-mediated post-transcriptional regulation for maintaining a specific cell state.

In Vitro Modeling of Human Germ Cell Development Using Pluripotent Stem Cells.

Due to differences across species, the mechanisms of cell fate decisions determined in mice cannot be readily extrapolated to humans. In this study, we developed a feeder- and xeno-free culture protocol that efficiently induced human pluripotent stem cells (iPSCs) into PLZF+/GPR125+/CD90+ spermatogonium-like cells (SLCs). These SLCs were enriched with key genes in germ cell development such as MVH, DAZL, GFRα1, NANOS3, and DMRT1. In addition, a small fraction of SLCs went through meiosis in vitro to develop into haploid cells. We further demonstrated that this chemically defined induction protocol faithfully recapitulated the features of compromised germ cell development of PSCs with NANOS3 deficiency or iPSC lines established from patients with non-obstructive azoospermia. Taken together, we established a powerful experimental platform to investigate human germ cell development and pathology related to male infertility.