Fig. 2
From: Role of PI3K/AKT pathway in squamous cell carcinoma with an especial focus on head and neck cancers
A schematic representation of the role of several ncRNAs in regulating the PI3K/AKT/mTOR signaling pathway in OSCC, TSCC and Cutaneous SCC. Accumulating evidence has revealed that various ncRNAs (lncRNAs, circRNAs, and miRNAs) could be negatively involved in triggering different kinds of SCCs via activating PI3K/AKT/mTOR signaling cascade. As an illustration, previous study has authenticated that up-regulation of lncRNA MALAT1 could promote the proliferation, migration, and invasion of tongue cancer cells via increasing the expression levels of AKT and MMP-9 [72]. Another finding confirms that overexpression of miR-21-5p could inhibit apoptosis via down-regulating the expression levels of PDCD4 as well as pro-apoptotic protein Bax and up-regulating FOXO1 and Bcl2 through directly activating the PI3K/AKT pathway in tongue squamous cell carcinoma [79]. Furthermore, mounting research has demonstrated that miRNA‑451a via directly targeting PDPK1 could suppress cutaneous squamous cell carcinoma development by modulating the PI3K/AKT signaling pathway [117]. Green lines indicate the positive regulatory effect among ncRNAs and their targets, and red lines depict negative one among them. All the information regarding the role of these ncRNAs involved in the regulation of the PI3K/AKT signaling pathway in several kinds of squamous cell carcinomas can be seen in Tables 6, 7