Search results for " P16"

MYC and EGR1 synergize to trigger tumor cell death by controlling NOXA and BIM transcription upon treatment with the proteasome inhibitor bortezomib

2014

The c-MYC (MYC afterward) oncogene is well known for driving numerous oncogenic programs. However, MYC can also induce apoptosis and this function of MYC warrants further clarification. We report here that a clinically relevant proteasome inhibitor significantly increases MYC protein levels and that endogenous MYC is necessary for the induction of apoptosis. This kind of MYC-induced cell death is mediated by enhanced expression of the pro-apoptotic BCL2 family members NOXA and BIM. Quantitative promoter-scanning chromatin immunoprecipitations (qChIP) further revealed binding of MYC to the promoters of NOXA and BIM upon proteasome inhibition, correlating with increased transcription. Both pr…

Anti-proliferative and pro-apoptotic activity of whole extract and isolated indicaxanthin from Opuntia ficus-indica associated with re-activation of …

2014

Phytochemicals may exert chemo-preventive effects on cells of the gastro-intestinal tract by modulating epigenome-regulated gene expression. The effect of the aqueous extract from the edible fruit of Opuntia ficus-indica (OFI extract), and of its betalain pigment indicaxanthin (Ind), on proliferation of human colon cancer Caco-2 cells has been investigated. Whole extract and Ind caused a dose-dependent apoptosis of proliferating cells at nutritionally relevant amounts, with IC50 400 ± 25 mg fresh pulp equivalents/mL, and 115 ± 15 μM (n = 9), respectively, without toxicity for post-confluent differentiated cells. Ind accounted for ∼80% of the effect of the whole extract. Ind did not cause ox…

DNA damage causes TP53-dependent coupling of self-renewal and senescence pathways in embryonal carcinoma cells.

2013

Recent studies have highlighted an apparently paradoxical link between self-renewal and senescence triggered by DNA damage in certain cell types. In addition, the finding that TP53 can suppress senescence has caused a re-evaluation of its functional role in regulating these outcomes. To investigate these phenomena and their relationship to pluripotency and senescence, we examined the response of the TP53-competent embryonal carcinoma (EC) cell line PA-1 to etoposide-induced DNA damage. Nuclear POU5F1/OCT4A and P21CIP1 were upregulated in the same cells following etoposide-induced G 2M arrest. However, while accumulating in the karyosol, the amount of OCT4A was reduced in the chromatin fract…

An immunohistochemical study of the distribution of p 16 protein in oral mucosa in smokers, non-smokers and in frictional keratosis

2009

Objective: Our study aimed to characterize alteration in the immunohistochemical p16 expression in normal oral mucosa and non-neoplastic hyperproliferative disorders (i.e. frictional keratosis and mucosa from smokers). Study design: 43 specimen of oral mucosa were examined using immunohistochemistry. Results: In normal mucosa, there was strong positive nuclear staining in a proportion of fibroblasts and endothelial cells in the lamina propria, with variable expression in nuclei of the epithelial layer. However, when the patient?s tobacco smoking was examined, p16 nuclear staining in oral epithelium was seen in 4/20 (20%) of smokers and 0/23 (0%) of non-smokers. In every case of frictional k…

La valutazione dell'iperespressione della proteina p16INK4a come possibile biomarcatore prognostico nelle lesioni cervicali intraepiteliali di basso …

2014

Prognostic significance of p16INK4a alterations and 9p21 loss of heterozigosity in locally advanced laryngeal squamous cell carcinoma

2002

The p16INK4a gene, localized within chromosome 9p21, has been identified as a cyclin-dependent kinase inhibitor and may negatively regulate the cell cycle acting as a tumor suppressor. Genetic alterations involving the 9p21 region are common in human cancers. A consecutive series of 64 untreated patients (median of follow up 53 months) undergoing surgical resection for locally advanced laryngeal squamous-cell carcinomas (LSCCs) has been studied prospectively. Our purpose was to investigate p16 alterations (9p21 allelic loss, hypermethylation and point mutations) and their possible association with clinico-pathological data and flow cytometric variables (DNA-ploidy and S-phase fraction (SPF)…

Predictive role of histological features and Ki67 pattern on high-risk HPV presence in atypical cervical lesions

2007

The most frequently detected alterations of squamous cervical epithelia consist of metaplastic/reactive conditions and human papillomavirus (HPV)-related dysplastic lesions. These latter are traditionally identified as cervical intraepithelial neoplasia (CIN1, 2 or 3) or, in the Bethesda System, as low-grade squamous intraepithelial lesions (LSIL), including CIN1, and high-grade SIL, including CIN2 and CIN3. Some HPV-induced lesions, which are not characterized by obvious dysplasia, are often diagnosed as LSIL. In these lesions, which are hereafter referred to as cervical atipical lesions (CAL), histological features of HPV infection (namely, koilocytosis, multinucleation, acanthosis, papil…

Increased dosage of Ink4/Arf protects against glucose intolerance and insulin resistance associated with aging

2013

Recent genome-wide association studies have linked type-2 diabetes mellitus to a genomic region in chromosome 9p21 near the Ink4/Arf locus, which encodes tumor suppressors that are up-regulated in a variety of mammalian organs during aging. However, it is unclear whether the susceptibility to type-2 diabetes is associated with altered expression of the Ink4/Arf locus. In the present study, we investigated the role of Ink4/Arf in age-dependent alterations of insulin and glucose homeostasis using Super-Ink4/Arf mice which bear an extra copy of the entire Ink4/Arf locus. We find that, in contrast to age-matched wild-type controls, Super-Ink4/Arf mice do not develop glucose intolerance with agi…