Generation of PTEN-knockout (-/-) murine prostate cancer cells using the CRISPR/Cas9 system and comprehensive gene expression profiling

Abstract

Phosphatase and tensin homolog (PTEN) deficiency is associated with development, progression, and metastasis of various cancers. However, changes in gene expression associated with PTEN deficiency have not been fully characterized. To explore genes with altered expression in PTEN-deficient cells, the present study generated a PTEN-knockout cell line (?PTEN) from a mouse prostate cancer-derived cell line using the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (CRISPR/Cas9) gene editing system. Following transfection of the CRISPR/Cas9 construct, DNA sequencing was performed to identify deletion of the Pten locus and PTEN inactivation was verified by western blotting. The ?PTEN cell line exhibited enhanced RAC-alpha serine/threonine-protein kinase phosphorylation and cyclin D1 expression. In addition, an increase in cell proliferation and colony formation was observed in the ?PTEN cell line. Gene expression profiling experiments were analyzed with microarray and microRNA (miRNA) arrays. In the microarray analysis, 111 genes exhibited =10-fold increased expression compared with the parent strain and mock cell line and 23 genes were downregulated. The only miRNA with increased expression of 10-fold or more was mmu-miR-210-3p. Genes with enhanced expression included genes involved in the development, progression, and metastasis of cancer such as Tet methylcytosine dioxygenase 1, twist family BHLH transcription factor 2, C-fos-induced growth factor and Wingless-Type MMTV Integration Site Family, Member 3, and genes involved in immunosuppression such as Arginase 1. The results of the present study suggest that PTEN deficiency mobilizes a variety of genes critical for cancer cell survival and host immune evasion.