Human colorectal cancer stem cells (CSCs) are tumour initiating cells that can self-renew and are highly tumorigenic and chemoresistant. While genetic mutations associated with human colorectal cancer development are well-known, little is known about how and whether epigenetic factors specifically contribute to the functional properties of human colorectal CSCs. Here we report that the KDM3 family of histone demethylases plays an important role in tumorigenic potential and survival of human colorectal CSCs by epigenetically activating Wnt target gene transcription. The depletion of KDM3 inhibits tumorigenic growth and chemoresistance of human colorectal CSCs. Mechanistically, KDM3 not only directly erases repressive H3K9me2 marks, but also helps to recruit histone methyltransferase MLL1 to promote H3K4 methylation, thereby promoting Wnt target gene transcription. Our results suggest that KDM3 is a critical epigenetic factor in Wnt signalling that orchestrates chromatin changes and transcription in human colorectal CSCs, identifying potential therapeutic targets for effective elimination of CSCs.

Pulp capping, or placing dental materials directly onto the vital pulp tissues of affected teeth, is a dental procedure that aims to regenerate reparative dentin. Several pulp capping materials are clinically being used, and calcium ion (Ca(2+)) released from these materials is known to mediate reparative dentin formation. ORAI1 is an essential pore subunit of store-operated Ca(2+) entry (SOCE), which is a major Ca(2+) influx pathway in most nonexcitable cells. Here, we evaluated the role of ORAI1 in mediating the odontogenic differentiation and mineralization of dental pulp stem cells (DPSCs). During the odontogenic differentiation of DPSCs, the expression of ORAI1 increased in a time-dependent manner. DPSCs knocked down with ORAI1 shRNA (DPSC/ORAI1sh) or overexpressed with dominant negative mutant ORAI1(E106Q) (DPSC/E106Q) exhibited the inhibition of Ca(2+) influx and suppression of odontogenic differentiation and mineralization as demonstrated by alkaline phosphatase (ALP) activity/staining as well as alizarin red S staining when compared with DPSCs of their respective control groups (DPSC/CTLsh and DPSC/CTL). The gene expression for odontogenic differentiation markers such as osteocalcin, bone sialoprotein, and dentin matrix protein 1 (DMP1) was also suppressed. When DPSC/CTL or DPSC/E106Q cells were subcutaneously transplanted into nude mice, DPSC/CTL cells induced mineralized tissue formation with significant increases in ALP and DMP1 staining in vivo, whereas DPSC/E106Q cells did not. Collectively, our data showed that ORAI1 plays critical roles in the odontogenic differentiation and mineralization of DPSCs by regulating Ca(2+) influx and that ORAI1 may be a therapeutic target to enhance reparative dentin formation.

Synopsis The long-term use of calcium hydroxide and the recent increase in the use of hydraulic calcium-silicate cements as direct pulp-capping materials provide important clues in terms of how reparative dentin may be induced to form a “biological seal” to protect the underlying pulp tissues. In this review article, we will discuss clinical and molecular perspectives of reparative dentin formation based on evidence learned from the use of these pulp-capping materials. We will also discuss the emerging role of calcium as an odontoinductive component in these pulp-capping materials.

Transposons are known to participate in tissue aging, but their effects on aged stem cells remain unclear. Here, we report that in the Drosophila ovarian germline stem cell (GSC) niche, aging-related reductions in expression of Piwi (a transposon silencer) derepress retrotransposons and cause GSC loss. Suppression of Piwi expression in the young niche mimics the aged niche, causing retrotransposon depression and coincident activation of Toll-mediated signaling, which promotes Glycogen synthase kinase 3 activity to degrade β-catenin. Disruption of β-catenin-E-cadherin-mediated GSC anchorage then results in GSC loss. Knocking down gypsy (a highly active retrotransposon) or toll, or inhibiting reverse transcription in the piwi-deficient niche, suppresses GSK3 activity and β-catenin degradation, restoring GSC-niche attachment. This retrotransposon-mediated impairment of aged stem cell maintenance may have relevance in many tissues, and could represent a viable therapeutic target for aging-related tissue degeneration.

Objective Emerging studies have demonstrated the promising clinical value of circulating tumor cells (CTCs) for diagnosis, disease assessment, treatment monitoring and prognosis in epithelial ovarian cancer. However, the clinical application of CTC remains restricted due to diverse detection techniques with variable sensitivity and specificity and a lack of common standards. Methods We enrolled 160 patients with epithelial ovarian cancer as the experimental group, and 90 patients including 50 patients with benign ovarian tumor and 40 healthy females as the control group. We enriched CTCs with immunomagnetic beads targeting two epithelial cell surface antigens (EpCAM and MUC1), and used multiple reverse transcription-polymerase chain reaction (RT-PCR) detecting three markers (EpCAM, MUC1 and WT1) for quantification. And then we used a binary logistic regression analysis and focused on EpCAM, MUC1 and WT1 to establish an optimized CTC detection model. Results The sensitivity and specificity of the optimized model is 79.4% and 92.2%, respectively. The specificity of the CTC detection model is significantly higher than CA125 (92.2% vs . 82.2%, P=0.044), and the detection rate of CTCs was higher than the positive rate of CA125 (74.5% vs. 58.2%, P=0.069) in early-stage patients (stage I and II). The detection rate of CTCs was significantly higher in patients with ascitic volume ≥500 mL, suboptimal cytoreductive surgery and elevated serum CA125 level after 2 courses of chemotherapy (P<0.05). The detection rate of CTC EpCAM + and CTC MUC1+ was significantly higher in chemo-resistant patients (26.3% vs . 11.9%; 26.4% vs . 13.4%, P<0.05). The median progression-free survival time for CTC MUC1+ patients trended to be longer than CTC MUC1− patients, and overall survival was shorter in CTC MUC1+ patients (P=0.043). Conclusions Our study presents an optimized detection model for CTCs, which consists of the expression levels of three markers (EpCAM, MUC1 and WT1). In comparison with CA125, our model has high specificity and demonstrates better diagnostic values, especially for early-stage ovarian cancer. Detection of CTC EpCAM+ and CTC MUC1+ had predictive value for chemotherapy resistance, and the detection of CTC MUC1+ suggested poor prognosis.