Project description:TAp63 is a transcription factor belonging to the p53 family with important tumor suppressive functions. We show that TAp63-/- mice exhibit an increased susceptibility to UVR-induced cutaneous squamous cell carcinoma (cuSCC). These tumors showed global disruption of miRNA and mRNA expression when compared to tumors arising in wild-type mice. A comparison to similarly sequenced human cuSCC tumors identified miR-30c-2* and miR-497 as being significantly underexpressed in cuSCC. Reintroduction of these miRNAs significantly inhibited the growth of cuSCC cell lines and xenografts. Proteomic profiling of cells transfected with either miRNA showed significant downregulation of proteins related to cell cycle progression and mitosis. A cross-platform comparison of the RNAseq and proteomics signatures identified 7 downregulated proteins, which are also frequently overexpressed in both mouse and human cuSCC. Knockdown of AURKA, KIF18B, PKMYT1, and ORC1 in cuSCC cell lines suppressed tumor cell proliferation and induced cell death. Additionally, we found that an investigational, oral, selective inhibitor of AURKA suppressed cuSCC cell growth and induced cell death, and showed anti-tumor effects in vivo. Our data establishes TAp63 as an essential regulator of miRNA expression during skin carcinogenesis and reveals a novel network of miRNAs and mRNAs, which include potential targets for therapeutic intervention.
Project description:The goal of this study is to compare the differences in the global mRNA expression of WT and TAp63-/- skin and SCC TAp63 is a p53 family member and potent tumor and metastasis suppressor. Here, we show that TAp63-/- mice exhibit an increased susceptibility to UVR- induced cutaneous squamous cell carcinoma (cuSCC). A human-to-mouse comparison of cuSCC tumors identified miR-30c-2* and miR-497 as underexpressed in TAp63-deficient cuSCC. Reintroduction of these microRNAs significantly inhibited the growth of cuSCC cell lines and tumors. Proteomic profiling of cells expressing either microRNA showed downregulation of cell cycle progression and mitosis associated proteins. A mouse to human and cross- platform comparison of RNA-Seq and proteomics data identified a 7-gene signature, including AURKA, KIF18B, PKMYT1, and ORC1, which were overexpressed in cuSCC. Knockdown of these factors in cuSCC cell lines suppressed tumor cell proliferation and induced apoptosis. Additionally, selective inhibition of AURKA suppressed cuSCC cell proliferation, induced apoptosis, and showed anti-tumor effects in vivo. Finally, treatment with miR-30c-2* or miR-497 microRNA mimics was highly effective in suppressing cuSCC growth in vivo. Our data establishes TAp63 as an essential regulator of novel microRNAs that can be therapeutically targeted for potent suppression of cuSCC.
Project description:TAp63 is a p53 family member and potent tumor and metastasis suppressor. Here, we show that TAp63-/- mice exhibit an increased susceptibility to ultraviolet radiation-induced cutaneous squamous cell carcinoma (cuSCC). A human-to-mouse comparison of cuSCC tumors identified miR-30c-2* and miR-497 as underexpressed in TAp63-deficient cuSCC. Reintroduction of these miRNAs significantly inhibited the growth of cuSCC cell lines and tumors. Proteomic profiling of cells expressing either miRNA showed downregulation of cell-cycle progression and mitosis-associated proteins. A mouse to human and cross-platform comparison of RNA-sequencing and proteomics data identified a 7-gene signature, including AURKA, KIF18B, PKMYT1, and ORC1, which were overexpressed in cuSCC. Knockdown of these factors in cuSCC cell lines suppressed tumor cell proliferation and induced apoptosis. In addition, selective inhibition of AURKA suppressed cuSCC cell proliferation, induced apoptosis, and showed antitumor effects in vivo. Finally, treatment with miR-30c-2* or miR-497 miRNA mimics was highly effective in suppressing cuSCC growth in vivo. Our data establish TAp63 as an essential regulator of novel miRNAs that can be therapeutically targeted for potent suppression of cuSCC. SIGNIFICANCE: This study provides preclinical evidence for the use of miR-30c-2*/miR-497 delivery and AURKA inhibition in the treatment of cuSCC, which currently has no FDA-approved targeted therapies.See related commentary by Parrales and Iwakuma, p. 2439.
Project description:TP63 (p63) is strongly expressed in lower-grade carcinomas of head-and-neck, skin, breast, urothelium, etc. to maintain the well-differentiated phenotype. TP63 has two transcription start sites at exon 1 and exon 3’ to produce TAp63 and DeltaNp63 isoforms, respectively. The major protein, DeltaNp63alpha, functions as a core factor to organize super enhancers of genes essential for epidermal/craniofacial differentiation and for self-activation of DeltaNp63. To examine whether very weakly expressed TAp63 has a specific role, we disrupted exon 1 by CRISPR-Cas9 homology directed repair (HDR) in a head and neck squamous cell carcinoma (SCC) line. Surprisingly, TAp63 knockout cells, with either ‘monoallelic HDR and a frameshift deletion on the other allele’ or ‘biallelic HDR’, caused DeltaNp63 silencing. Loss of keratinocyte-specific gene expression, replacement of KRT5 with VIM, and transcriptional suppression of cell-cell and cell-matrix adhesion components indicated core events of epithelial mesenchymal transition. Most of the positively and negatively impacted genes including DeltaNp63 displayed local CpG methylation changes. Furthermore, DeltaNp63 expression was partially rescued by transfection of TAp63alpha, followed by incubation with DNA methyltransferase inhibitor Zebularine. This study suggests that TAp63 is indispensable for DeltaNp63 expression by which keratinocyte-specific epigenome is maintained in SCC.
Project description:TP63 (p63) is strongly expressed in lower-grade carcinomas of head-and-neck, skin, breast, urothelium, etc. to maintain the well-differentiated phenotype. TP63 has two transcription start sites at exon 1 and exon 3’ to produce TAp63 and DeltaNp63 isoforms, respectively. The major protein, DeltaNp63alpha, epigenetically activates genes essential for epidermal/craniofacial differentiation, including DeltaNp63 itself. To examine whether weakly expressed TAp63 has a specific role, we disrupted exon 1 by CRISPR-Cas9 homology directed repair in a head and neck squamous cell carcinoma (SCC) line. Surprisingly, TAp63 knockout cells, either by monoallelic GFP cassette insertion paired with a frameshift deletion allele or by biallelic GFP cassette insertion, caused DeltaNp63 silencing. Loss of keratinocyte-specific gene expression, switching of intermediate filaments from KRT(s) to VIM, and suppression of cell-cell and cell-matrix adhesion components indicated core events of epithelial mesenchymal transition. Most of the positively and negatively impacted genes including DeltaNp63 displayed local DNA methylation changes. Furthermore, DeltaNp63 expression was partially rescued by transfection of TAp63alpha followed by incubation with DNA methyltransferase inhibitor Zebularine. TAp63, as a minor part of TP63 gene, may possibly be involved in the auto-activation mechanism of DeltaNp63 by which keratinocyte-specific epigenome is maintained in SCC.
Project description:By comparing the comprehensive gene expression profiles between human Th17 cells overexpressing TAp63 and those with TAp63 knockdown, FOXP3 was identified as one of the downregulated genes by TAp63