guo, z. | bioRxiv Science

bioRxiv2021

MicroRNA-27a-5p inhibits proliferation, migration and invasion and promotes apoptosis of Wilms tumor cell by targeting PBOV1

Wilms tumor is the most common type of renal tumor in children. MicroRNAs (miRNA) are small non-coding RNAs that play crucial regulatory roles in tumorigenesis. We aimed to study the expression profile and function of miR-27a-5p in Wilms tumor. MiR-27a-5p expression was downregulated in human Wilms tumor tissues. Functionally, overexpression of miR-27a-5p promoted cell apoptosis of Wilms tumor cells. Furthermore, upregulated miR-27a-5p delayed xenograft Wilms tumor tumorigenesis in vivo. Bioinformatics analysis predicted miR-27-5p directly targeted to the 3-untranslated region (UTR) of PBOV1 and luciferase reporter assay confirmed the interaction between miR-27a-5p and PBOV1. The function of PBOV1 in Wilms tumor was evaluated in vitro and knockdown of PBOV1 dampened cell migration. In addition, overexpression of PBOV1 antagonized the tumor-suppressive effect of miR-27a-5p in Wilms tumor cells. Collectively, our findings reveal the regulatory axis of miR-27-5p/PBOV1 in Wilms tumor and miR-27a-5p might serve as a novel therapeutic target in Wilms tumor.

cell biology↗

bioRxiv2021

Brazil Nut Effect Drives Pattern Formation in Early Mammalian Embryos

The formation of three-dimensional ordered spatial patterns, which is essential for embryonic development, tissue regeneration, and cancer metastasis, is mainly guided by the chemical concentration gradient of morphogens. However, since no chemical concentration gradient has been observed in the early embryonic development (pre-implantation) of mammals, the pattern formation mechanism has been unsolved for a long time. During the second cell fate decision of mouse embryos, the inner cell mass (ICM) segregates into topographically regionalized epiblast (EPI) and primitive endoderm (PrE) layers. Here, we report that the segregation process of PrE/EPI precursors coincides with an emerged periodic expansion-contraction vibration of the blastocyst cavity, which induces phase transition in the ICM compartment to a higher fluidity state and generates directional tissue flows. By experiments and modeling, we demonstrate that the spatial segregation of PrE and EPI precursors is mediated by a "Brazil nut effect"-like viscous segregation mechanism in which PrE precursors with low affinity gradually migrate to the surface of ICM along with the tissue flow, while EPI precursors with high affinity remains inside ICM under cavity vibration. Artificially manipulation of the frequency and amplitude of cavity vibration could control the process of spatial separation as well as lineage specification of PrE/EPI. Furthermore, disruption of the cavity vibration in the initial stage after segregation could reverse the ICM cells back to a mixed state. Therefore, this study reveals a fundamental mechanism that guarantees the robustness of cell segregation and pattern formation without specific morphogens in early mammalian embryos. Our model also emphasizes a conserved function of cavity structure that widely exists in organisms as an energy reservoir and converter between different forms, such as chemical and mechanical energy.

developmental biology↗