Jie Long

The role of p53 in renal fibrosis is still controversial, and its underlying mechanisms remain not clear. Here, we showed that the pharmacological inhibition and genetic deletion of p53 in proximal tubular cells can attenuate renal dysfunction, tubular epithelial disruption, and interstitial fibrosis in db/db and STZ-induced diabetic nephrology (DN) mice. In human renal proximal tubule (human kidney 2 [HK-2]) cells, inhibition of p53 by PIF reduced the high glucose (HG)-induced extracellular matrix (ECM) accumulation and reversed the inhibitory effect of HG on mRNA expression levels of lncRNA zinc finger E-box binding homeobox1-antisense RNA 1 (ZEB1-AS1) and ZEB1. Interestingly, our results demonstrated that both lncRNA ZEB1-AS1 and ZEB1 exhibited an anti-fibrotic role, while ZEB1 is positively regulated by lncRNA ZEB1-AS1 during HG treatment. Mechanistically, lnc ZEB1-AS1 bound directly to H3K4 methyltransferase myeloid and lymphoid or mixed-lineage leukemia 1 (MLL1) and promoted H3K4me3 histone modification on ZEB1 promoter, which was reduced by HG treatment. ChIP analysis indicated the binding of p53 to the promoter region of lnc ZEB1-AS1. Furthermore, the findings were verified by the kidney biopsy samples from patients with DN. Taken all together, our results suggest that p53 may be a therapeutic target for renal fibrosis in DN.

BACKGROUND: Our pilot study using miRNA PCR array found that miRNA-29b (miR-29b) is differentially expressed in primary cultured CD133-positive A549 cells compared with CD133-negative A549 cells. METHODS: Ten human non-small cell lung cancer (NSCLC) cell lines and samples from thirty patients with NSCLC were analyzed for the expression of miR-29b by quantitative RT-PCR. Bioinformatics analysis combined with tumor metastasis PCR array showed the potential target genes for miR-29b. miR-29b lentivirus and inhibitors were transfected into NSCLC cells to investigate its role on regulating cell proliferation which was measured by CCK-8 assay in vitro and nude mice xenograft tumor assay in vivo. Cell motility ability was evaluated by transwell assay. The target genes of miR-29b were determined by luciferase assay, quantitative RT-PCR and western blot. RESULTS: Bioinformatics analysis combined with tumor metastasis PCR array showed that matrix metalloproteinase 2 (MMP2) and PTEN could be important target genes of miR-29b. The expression of miR-29b was down regulated in NSCLC tissues compared to the normal tissues. Clinicopathological analysis demonstrated that miR-29b had significant negative correlation with lymphatic metastasis. The gain-of-function studies revealed that ectopic expression of miR-29b decreased cell proliferation, migration and invasion abilities of NSCLC cells. In contrasts, loss-of-function studies showed that inhibition of miR-29b promoted cell proliferation, migration and invasion of NSCLC cells in vitro. Nude mice xenograft tumor assay confirmed that miR-29b inhibited lung cancer growth in vivo. High-invasion (A549-H) and low-invasion (A549-L) NSCLC cell sublines from A549 cells were created by using the repeated transwell assay aimed to confirm the effect of miR-29b on migration and invasion of NSCLC. Furthermore, the dual-luciferase reporter assay demonstrated that miR-29b inhibited the expression of the luciferase gene containing the 3'-UTRs of MMP2 and PTEN mRNA. Western blotting and quantitative RT-PCR indicated that miR-29b down-regulated the expression of MMP2 at the protein and mRNA levels. CONCLUSION: Taken together, our results demonstrate that miR-29b serves as a tumor metastasis suppressor, which suppresses NSCLC cell metastasis by directly inhibiting MMP2 expression. The results show that miR-29b may be a novel therapeutic candidate target to slow NSCLC metastasis.