Retinoic acid negatively regulates dact3b expression in the hindbrain of zebrafish embryos

The Role of DACT Family Members in Tumorigenesis and Tumor Progression

Disheveled-associated antagonist of β-catenin (DACT), which ubiquitously expressed in human tissue, is critical for regulating cell proliferation and several developmental processes in different cellular contexts. In addition, DACT is essential for some other cellular processes, such as cell apoptosis, migration and differentiation. Given the importance of DACT in these cellular processes, many scientists are gradually interested in studying the role of DACT in tumorigenesis and cancer progression. This review article focuses on the latest research regarding the essential functions and potential DACT mechanisms in the occurrence and progression of tumors. Our study indicates that DACT may act as a tumor biomarker for cancer diagnosis and prognosis, as well as a promising therapeutic target in cancers.

CKD-581 Downregulates Wnt/β-Catenin Pathway by DACT3 Induction in Hematologic Malignancy

The present study evaluated the anti-cancer activity of histone deacetylase (HDAC)-inhibiting CKD-581 in multiple myeloma (MM) and its pharmacological mechanisms. CKD-581 potently inhibited a broad spectrum of HDAC isozymes. It concentration-dependently inhibited proliferation of hematologic cancer cells including MM (MM.1S and RPMI8226) and T cell lymphoma (HH and MJ). It increased the expression of the dishevelled binding antagonist of β-catenin 3 (DACT3) in T cell lymphoma and MM cells, and decreased the expression of c-Myc and β-catenin in MM cells. Additionally, it enhanced phosphorylated p53, p21, cleaved caspase-3 and the subG1 population, and reversely, downregulated cyclin D1, CDK4 and the anti-apoptotic BCL-2 family. Finally, administration of CKD-581 exerted a significant anti-cancer activity in MM.1S-implanted xenografts. Overall, CKD-581 shows anti-cancer activity via inhibition of the Wnt/β-catenin signaling pathway in hematologic malignancies. This finding is evidence of the therapeutic potential and rationale of CKD-581 for treatment of MM.

Butyrate mediates anti-inflammatory effects of Faecalibacterium prausnitzii in intestinal epithelial cells through Dact3

The commensal bacterium Faecalibacterium prausnitzii plays a key role in inflammatory bowel disease (IBD) pathogenesis and serves as a general health biomarker in humans. However, the host molecular mechanisms that underlie its anti-inflammatory effects remain unknown. In this study we performed a transcriptomic approach on human intestinal epithelial cells (HT-29) stimulated with TNF-α and exposed to F. prausnitzii culture supernatant (SN) in order to determine the impact of this commensal bacterium on intestinal epithelial cells. Moreover, modulation of the most upregulated gene after F. prausnitzii SN contact was validated both in vitro and in vivo. Our results showed that F. prausnitzii SN upregulates the expression of Dact3, a gene linked to the Wnt/JNK pathway. Interestingly, when we silenced Dact3 expression, the effect of F. prausnitzii SN was lost. Butyrate was identified as the F. prausnitzii effector responsible for Dact3 modulation. Dact3 upregulation was also validated in vivo in both healthy and inflamed mice treated with either F. prausnitzii SN or the live bacteria, respectively. Finally, we demonstrated by colon transcriptomics that gut microbiota directly influences Dact3 expression. This study provides new clues about the host molecular mechanisms involved in the anti-inflammatory effects of the beneficial commensal bacterium F. prausnitzii.

Methylation of DACT2 promotes breast cancer development by activating Wnt signaling

Breast cancer is the most common malignant tumor in women worldwide. To explore the role of DACT2 in breast cancer, 5 cell lines and 153 cases of primary cancer were studied. The expression of DACT2 was detected in BT474, MDA-MB-231 and BT549 cells, while no expression was found in MDA-MB-468 and HBL100 cells. Complete methylation of DACT2 was found in MDA-MB-468 and HBL100 cells, partial methylation was observed in BT474 and BT549 cells, and no methylation was detected in MDA-MB-231 cells. Restoration of DACT2 expression was induced by 5-Aza in MDA-MB-468 and HBL100 cells. DACT2 was methylated in 49.7% (76/153) of primary breast cancer samples. Methylation of DACT2 was significantly associated with tumor size (P < 0.05). Reduced DACT2 expression was significantly associated with promoter region methylation in primary breast cancer (P < 0.05). DACT2 suppressed breast cancer cell growth and induced G1/S phase arrest in breast cancer cells. DACT2 inhibited Wnt/β-catenin signaling in human breast cancer cells and suppressed breast cancer cell tumor growth in xenograft mice. In conclusion, our results demonstrate that DACT2 is frequently methylated in human breast cancer, methylation of DACT2 activates Wnt signaling, and DACT2 suppresses breast cancer cell growth both in vitro and in vivo.