Expression levels of miR31 and miR92a were evaluated by real-time PCR using TaqMan probes; in addition, two oncogenes (KRAS and c-MYC) and two tumor suppressors (AMP-activated protein kinase [AMPK] and adenomatous tumors of polyposis coli [APC]) were quantified to validate the biological effects; normalization of expression levels were carried out by 2<sup>-ΔΔCt</sup>.Results were analyzed by one-way ANOVA.
The most common recurrent somatic mutations were in TP53 (36%), androgen receptor (AR) (22%), adenomatous polyposis coli (APC) (10%), neurofibromin 1 (NF1) (9%), epidermal growth factor receptor (EGFR), catenin beta-1 (CTNNB1), and AT-rich interactive domain-containing protein 1A (ARID1A) (6% each); and BRCA1, BRCA2, and phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) (5% each) The most common genes with increased copy numbers were AR (30%), MYC (20%), and BRAF (18%).
miR-582-5P was upregulated in the CRC specimens and cell lines and targeted the 3' untranslated region of APC directly. miR-582-5P overexpression increased cyclin D1 and c-MYC expression, which subsequently induced CRC cell proliferation in an APC-dependent manner.
Aberrant Wnt signaling mediated by mutations affecting APC (adenomatous polyposis coli) or beta-catenin initiates the majority of human colorectal cancers (CRC) and drives tumorigenesis through the activation of specific genes such as MYC.
The c-myc protein, which is reduced in the presence of wild-type APC, acts to repress caveolin-1 expression by acting at non-E-box containing elements in the caveolin-1 promoter.
Monoclonal antibodies raised by synthetic peptide immunisation were used to determine the distribution of the protein product of the c-myc gene by immunocytochemical staining of archival wax embedded material from patients with familial adenomatous polyposis.