curcumin and Wilms-Tumor

Wilms' tumor (WT) is the most common kidney tumor of children. The transformation suppressor gene RECK, which codes membrane-anchored glycoprotein, frequently downregulates multiple matrix metalloproteinases in tumors. And curcumin, which is a polyphenlic compound separated from turmeric, has antitumor effects on various cancers. However, the correlation of WT, RECK and curcumin is still unrevealed. In this study, we evaluated that the methylation degree of RECK was much higher in WT than in adjacent non-tumor tissues. And RECK methylation was closely associated with tumor metastasis in WT patients. After curcumin treatment, the level of RECK methylation was decreased significantly. And the expression of MMP2 and MMP9 was reduced consequently. Moreover, the proliferation, invasion and migration ability of WT cells were suppressed after curcumin treatment. Meanwhile, the apoptosis rate of WT cells was increased simultaneously. In nude mice model, curcumin restrained ability of tumorigenicity and promoted apoptosis of WT cells. Together, our results suggest that the RECK methylation can serve as a prognostic biomarker of WT. Moreover, curcumin could inhibit RECK methylation, thereby abates the expression of MMPs, and suppresses the tumor progression and metastasis of WT.

Topics: Animals; Apoptosis; Biomarkers, Tumor; Carcinogenesis; Cell Movement; Cell Proliferation; Child, Preschool; Curcumin; DNA Methylation; Down-Regulation; Female; GPI-Linked Proteins; Humans; Kidney Neoplasms; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Mice; Mice, Nude; Neoplasm Metastasis; Wilms Tumor

The Wilms' tumor 1 (WT1) gene is one of the regulating factors in cell proliferation and development. It is a double-functional gene: an oncogene and a tumor suppressor. This gene was found to be highly expressed in many leukemic cell lines and in patients with acute myeloid leukemia. In the present study, we demonstrated that the WT1 gene was commonly expressed in leukemic cell lines apart from U937 cells. The K562 cell line which expresses WT1 at a high level (mRNA and protein) was used in the entire experiment. By MTT and colony formation assays, we found that curcumin, an inhibitor of the WT1 protein, inhibited cell proliferation and clonogenicity in a time- and dose-dependent manner. It also caused cell cycle arrest at the G2/M phase. We then designed specific short hairpin RNAs (shRNAs) which could downregulate WT1 by 70-80% at the mRNA and protein levels. Reduction in the WT1 levels attenuated the proliferative ability and clonogenicity. Cell cycle progression analysis indicated that the proportion of cells in the G0/G1 phase increased while the proportion in the S phase decreased distinctively. ChIP-DNA selection and ligation (DSL) experiment identified a cohort of genes whose promoters are targeted by WT1. These genes were classified into different cellular signaling pathways using MAS software and included the Wnt/β-catenin pathway, MAPK signaling pathway, apoptosis pathway, and the cell cycle. We focused on the Wnt/β-catenin signaling pathway, and compared expression of several genes in the K562 cells transfected with the control shRNA and WT1-specific shRNA. β-catenin, an important gene in the Wnt canonical pathway, was downregulated after WT1 RNAi. Target genes of β-catenin which participate in cell proliferation and cell cycle regulation, such as CCND1 and MYC, were also significantly downregulated. Collectively, these data suggest that WT1 functions as an oncogene in leukemia cells, and one important mechanism is regulation of the Wnt/β-catenin pathway.

Topics: Apoptosis; beta Catenin; Cell Cycle; Cell Proliferation; Curcumin; Female; Gene Expression Regulation, Leukemic; Humans; K562 Cells; Promoter Regions, Genetic; RNA, Messenger; U937 Cells; Wilms Tumor; Wnt Signaling Pathway; WT1 Proteins