Phospho-ΔNp63α-dependent regulation of autophagic signaling through transcription and micro-RNA modulation

Abstract

Cisplatin was shown to induce the ataxia telangiectasia mutated (ATM)-dependent phosphorylation of tumor protein p63 isoform, (ΔNp63α), leading to a transcriptional regulation of specific genes implicated in the control of cell death of squamous cell carcinoma (SCC) cells. We previously observed that the cisplatin-induced phosphorylated (p)-ΔNp63α transcriptionally regulates the expression of specific microRNAs (miRNAs) in SCC cells. We found here that cisplatin exposure of SCC cells led to modulation of the members of the autophagic pathway, such as Atg1/Ulk1, Atg3, Atg4A, Atg5, Atg6/Becn1, Atg7, Atg9A and Atg10, by a direct p-ΔNp63α-dependent transcriptional regulation. We further found that specific miRNAs (miR-181a, miR-519a, miR-374a and miR-630), which are critical downstream targets of the p-ΔNp63α, modulated the protein levels of ATG5, ATG6/BECN1, ATG10, ATG12, ATG16L1 and UVRAG, adding another level of expression control for autophagic pathways in SCC cells upon cisplatin exposure. Our data support the notion that the cisplatin-induced p-ΔNp63α could regulate key pathways implicated in response of cancer cells to chemotherapeutics.

Phospho-ΔNp63α/microRNA network modulates epigenetic regulatory enzymes in squamous cell carcinomas

“…34 By global analysis of microRNA expression, we previously showed that cisplatin exposure led to a downregulation of 28 microRNAs (e.g., miR-519a-3p, miR-181a-5p, miR-374a-5p, miR-98-5p, miR-29c-3p, miR-22-3p, miR-34c-3p, miR-206, miR-429, miR-339-3p, miR-203a, miR-25-3p, miR-155-5p, and miR-148a-3p) by −5.18 to −19.27-fold, and upregulation of 15 microRNAs (e.g., miR-382-3p, miR-485-5p, miR-574-5p, miR92b-3p, miR-297, miR-185-5p, miR-885-3p, miR-194-5p, and miR-630) by 3.95-to 7.46-fold in SCC-11 cells compared with SCC-11M cells upon cisplatin exposure. [36][37][38][39] We further showed that cisplatin exposure altered microRNA expression in SCC-11 cells, resulting in downregulation of 7 microRNAs (e.g., miR-519-a-3p, miR-181a-5p, miR-374a-5p, miR-29c-3p, miR-98-5p, miR-22-3p, and miR-34c-3p, from −1.72 to −3.77-fold), and upregulation of 7 microRNAs (miR-382-3p, miR-485-5p, miR-574-5p, miR-297, miR-194-5p, miR-885-3p, and miR-630, from 2.08-to 4.98-fold), as shown in references 36-39.…”

“…[35][36][37][38][39] Using knock-in technology, we generated SCC-11 cells, which have been shown to produce wild-type ΔNp63α, and SCC-11M cells that exclusively express ΔNp63α-S385G mutant protein, with an altered ability to be phosphorylated by ATM kinase. 34 By global analysis of microRNA expression, we previously showed that cisplatin exposure led to a downregulation of 28 microRNAs (e.g., miR-519a-3p, miR-181a-5p, miR-374a-5p, miR-98-5p, miR-29c-3p, miR-22-3p, miR-34c-3p, miR-206, miR-429, miR-339-3p, miR-203a, miR-25-3p, miR-155-5p, and miR-148a-3p) by −5.18 to −19.27-fold, and upregulation of 15 microRNAs (e.g., miR-382-3p, miR-485-5p, miR-574-5p, miR92b-3p, miR-297, miR-185-5p, miR-885-3p, miR-194-5p, and miR-630) by 3.95-to 7.46-fold in SCC-11 cells compared with SCC-11M cells upon cisplatin exposure.…”

MicroRNA

“…[30][31][32] Cisplatin treatment activates autophagy in multiple cancer cells and decreases the level of several miRNAs at the same time, which target multiple key regulators in autophagy, such as miR-199a-5p against ATG7 in HCC, 33 miR-181a and miR-374a against ATG5, miR-630 against ATG12 and miR-519a against beclin-1, ATG10 and ATG16 in squamous cell carcinoma (SCC) cells. 34 The miRNA-mediated genes and pathways involved in autophagy are illustrated in Figure 1. feedback loop between p53 and miR-502.…”

“…Cisplatin has been shown to induce autophagy in cancer cells 33,34 and activate p53 family members, 42,43 which, in turn, function as transcriptional regulators to affect downstream gene expression, including miRNAs. [44][45][46] In SCC cells, cisplatin exposure phosphorylates ΔNp63α, which directly regulates the transcription of many miRNAs.…”

“…[44][45][46] In SCC cells, cisplatin exposure phosphorylates ΔNp63α, which directly regulates the transcription of many miRNAs. 44 Among the direct targets, miR-181a, miR-519a, miR-374a and miR-630 has been shown to regulate autophagy-related proteins, 34 which suggests that miRNAs can modulate autophagy pathway at another translational level. A number of previous studies have reported the direct involvement of p53 in autophagy.…”