MiR-199a-3p Induces Mesenchymal to Epithelial Transition of Keratinocytes by Targeting RAP2B

Moamen Masalha, Tal Meningher, Adi Mizrahi, Aviv Barzilai, Hilla Tabibian-Keissar, Devorah Gur-Wahnon, Iddo Z. Ben-Dov, Joshua Kapenhas, Jasmine Jacob-Hirsch, Raya Leibowitz, Yechezkel Sidi, Dror Avni*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


Cutaneous squamous cell carcinoma (CSCC) is an epidermal skin cancer that evolves from normal epidermis along several pre-malignant stages. Previously we found specific miRNAs alterations in each step along these stages. miR-199a-3p expression decreases at the transition to later stages. A crucial step for epithelial carcinoma cells to acquire invasive capacity is the disruption of cell–cell contacts and the gain of mesenchymal motile phenotype, a process known as epithelial-to-mesenchymal transition (EMT). This study aims to study the role of decreased expression of miR-199a-3p in keratinocytes’ EMT towards carcinogenesis. First, we measured miR-199a-3p in different stages of epidermal carcinogenesis. Then, we applied Photoactivatable Ribonucleoside-Enhanced Crosslinking and Immunoprecipitation (PAR-CLIP) assay to search for possible biochemical targets of miR-199a-3p and verified that Ras-associated protein B2 (RAP2B) is a bona-fide target of miR-199a-3p. Next, we analyzed RAP2B expression, in CSCC biopsies. Last, we evaluated possible mechanisms leading to decreased miR-199a-3p expression. miR-199a-3p induces a mesenchymal to epithelial transition (MET) in CSSC cells. Many of the under-expressed genes in CSCC overexpressing miR-199a-3p, are possible targets of miR-199a-3p and play roles in EMT. RAP2B is a biochemical target of miR-199a-3p. Overexpression of miR-199a-3p in CSCC results in decreased phosphorylated focal adhesion kinase (FAK). In addition, inhibiting FAK phosphorylation inhibits EMT marker genes’ expression. In addition, we proved that DNA methylation is part of the mechanism by which miR-199a-3p expression is inhibited. However, it is not by the methylation of miR-199a putative promoter. These findings suggest that miR-199a-3p inhibits the EMT process by targeting RAP2B. Inhibitors of RAP2B or FAK may be effective therapeutic agents for CSCC.

Original languageEnglish
Article number15401
JournalInternational Journal of Molecular Sciences
Issue number23
StatePublished - Dec 2022


FundersFunder number
Meir and Edith Rosenfeld Foundation
Israel Cancer Association20160038
Tel Aviv University
Council for Higher Education


    • RAP2B
    • cutaneous squamous cell carcinoma (CSCC)
    • epithelial-mesenchymal transition (EMT)
    • miR-199a-3p


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