E47 Governs the MYC-CDKN1B/p27KIP1 -RB Network to Growth Arrest PDA Cells Independent of CDKN2A/p16INK4A and Wild-Type p53

Cellular and Molecular Gastroenterology and Hepatology
Kathleen M ScullyPamela Itkin-Ansari

Abstract

Oncogenic mutations in KRAS, coupled with inactivation of p53, CDKN2A/p16INK4A, and SMAD4, drive progression of pancreatic ductal adenocarcinoma (PDA). Overexpression of MYC and deregulation of retinoblastoma (RB) further promote cell proliferation and make identifying a means to therapeutically alter cell-cycle control pathways in PDA a significant challenge. We previously showed that the basic helix-loop-helix transcription factor E47 induced stable growth arrest in PDA cells in vitro and in vivo. Here, we identified molecular mechanisms that underlie E47-induced growth arrest in low-passage, patient-derived primary and established PDA cell lines. RNA sequencing was used to profile E47-dependent transcriptomes in 5 PDA cell lines. Gene Ontology analysis identified cell-cycle control as the most altered pathway. Small interfering RNA/short hairpin RNA knockdown, small-molecule inhibitors, and viral expression were used to examine the function of E47-dependent genes in cell-cycle arrest. Cell morphology, expression of molecular markers, and senescence-associated β-galactosidase activity assays identified cellular senescence. E47 uniformly inhibited PDA cell-cycle progression by decreasing expression of MYC, increasing the level...Continue Reading

Methods Mentioned

BETA
chip
Exome Sequencing
RNA-seq
Infection
flow cytometry
PCR

Software Mentioned

Torrent Suite
ImageJ
R package limma
RT 2 Profiler PCR
limma
Torrent Suite Variant Caller
R

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