Search results for "P21"
showing 10 items of 131 documents
Transcriptional repression of Bmp2 by p21(Waf1/Cip1) links quiescence to neural stem cell maintenance.
2013
Relative quiescence and self renewal are defining features of adult stem cells, but their potential coordination remains unclear. Subependymal neural stem cells (NSCs) lacking cyclin-dependent kinase (CDK) inhibitor (CKI) 1a (p21) exhibit rapid expansion that is followed by their permanent loss later in life. Here we demonstrate that transcription of the gene encoding bone morphogenetic protein 2 (Bmp2) in NSCs is under the direct negative control of p21 through actions that are independent of CDK. Loss of p21 in NSCs results in increased levels of secreted BMP2, which induce premature terminal differentiation of multipotent NSCs into mature non-neurogenic astrocytes in an autocrine and/or …
A p16INK4a-insensitive CDK4 mutant targeted by cytolytic T lymphocytes in a human melanoma.
1995
A mutated cyclin-dependent kinase 4 (CDK4) was identified as a tumor-specific antigen recognized by HLA-A2. 1-restricted autologous cytolytic T lymphocytes (CTLs) in a human melanoma. The mutated CDK4 allele was present in autologous cultured melanoma cells and metastasis tissue, but not in the patient's lymphocytes. The mutation, an arginine-to-cysteine exchange at residue 24, was part of the CDK4 peptide recognized by CTLs and prevented binding of the CDK4 inhibitor p16INK4a, but not of p21 or of p27KIP1. The same mutation was found in one additional melanoma among 28 melanomas analyzed. These results suggest that mutation of CDK4 can create a tumor-specific antigen and can disrupt the ce…
In vivo studies of altered expression patterns of p53 and proliferative control genes in chronic vitamin A deficiency and hypervitaminosis
2003
Several clinical trials have revealed that individuals who were given beta-carotene and vitamin A did not have a reduced risk of cancer compared to those given placebo; rather, vitamin A could actually have caused an adverse effect in the lungs of smokers [Omenn, G.S., Goodman, G.E., Thornquist, M.D., Balmes, J., Cullen, M.R., Glass, A., Keogh, J.P., Meyskens, F.L., Valanis, B., Williams, J.H., Barnhart, S. & Hammar, S. N. Engl. J. Med (1996) 334, 1150-1155; Hennekens, C.H., Buring, J.E., Manson, J.E., Stampfer, M., Rosner, B., Cook, N.R., Belanger, C., LaMotte, F., Gaziano, J.M., Ridker, P.M., Willet, W. & Peto, R. (1996) N. Engl. J. Med. 334, 1145-1149]. Using differential display techniq…
Prognostic Value of p53, p21/WAF1, Bcl-2, Bax, Bak and Ki-67 Immunoreactivity in pT1 G3 Urothelial Bladder Carcinomas
2001
pT1 G3 bladder carcinomas are heterogeneous with respect to tumor recurrence and progression. Whereas some urologists treat these carcinomas by repeated transurethral resections often followed by intravesical chemotherapy or BCG instillation, others recommend cystectomy after tumor recurrence or early cystectomy after the initial diagnosis. Our goal was to determine the prognostic value of p53, p21/WAF1, Bcl-2, Bax, Bak, and Ki-67 immunoreactivity in these tumors. There were 30 patients with a new histopathological diagnosis of pT1 G3 urothelial carcinoma based on a transurethral resection specimen. Representative sections of these specimens were examined for the above markers. All patients…
Biochemical and chemical characterization of Cynara cardunculus L. extract and its potential use as co-adjuvant therapy of chronic myeloid leukemia
2017
Abstract Ethnopharmacological relevance Ancient mediterranean diet was characterized by consuming the spontaneous forms of Cynara cardunculus L. (CCL), commonly called artichoke. Cultivated and/or spontaneous forms of CC studies have demonstrated that methanol extract of CCL flower and/or cynaropicrin showed remarkable anti-proliferative activity in vitro models of leukocyte cancer cell. Aim of the study Chronic myeloid leukemia (CML) is associated with a reciprocal translocation of the long arms of chromosomes 9 and 22 generating the BCR/ABL fusion gene, translated in the p210 BCR/ABL oncoprotein kinase. This chimeric protein is the target of a kinase inhibitor, imatinib, but the developme…
Cyclin-dependent kinase inhibitor p21 controls adult neural stem cell expansion by regulating Sox2 gene expression.
2012
Summary In the adult brain, continual neurogenesis of olfactory neurons is sustained by the existence of neural stem cells (NSCs) in the subependymal niche. Elimination of the cyclin-dependent kinase inhibitor 1A (p21) leads to premature exhaustion of the subependymal NSC pool, suggesting a relationship between cell cycle control and long-term self-renewal, but the molecular mechanisms underlying NSC maintenance by p21 remain unexplored. Here we identify a function of p21 in the direct regulation of the expression of pluripotency factor Sox2, a key regulator of the specification and maintenance of neural progenitors. We observe that p21 directly binds a Sox2 enhancer and negatively regulate…
Targeting components of the alternative NHEJ pathway sensitizes KRAS mutant leukemic cells to chemotherapy.
2014
Abstract Activating KRAS mutations are detected in a substantial number of hematologic malignancies. In a murine T-cell acute lymphoblastic leukemia (T-ALL) model, we previously showed that expression of oncogenic Kras induced a premalignant state accompanied with an arrest in T-cell differentiation and acquisition of somatic Notch1 mutations. These findings prompted us to investigate whether the expression of oncogenic KRAS directly affects DNA damage repair. Applying divergent, but complementary, genetic approaches, we demonstrate that the expression of KRAS mutants is associated with increased expression of DNA ligase 3α, poly(ADP-ribose) polymerase 1 (PARP1), and X-ray repair cross-comp…
Metabolic and Functional Genomic Studies Identify Deoxythymidylate Kinase as a target in LKB1 Mutant Lung Cancer
2013
Abstract The LKB1/STK11 tumor suppressor encodes a serine/threonine kinase, which coordinates cell growth, polarity, motility, and metabolism. In non–small cell lung carcinoma, LKB1 is somatically inactivated in 25% to 30% of cases, often concurrently with activating KRAS mutations. Here, we used an integrative approach to define novel therapeutic targets in KRAS-driven LKB1-mutant lung cancers. High-throughput RNA interference screens in lung cancer cell lines from genetically engineered mouse models driven by activated KRAS with or without coincident Lkb1 deletion led to the identification of Dtymk, encoding deoxythymidylate kinase (DTYMK), which catalyzes dTTP biosynthesis, as synthetica…
Cytotoxic Activity of Organotin(IV) Derivatives with Triazolopyrimidine Containing Exocyclic Oxygen Atoms
2020
In this study cytotoxicity of organotin(IV) compounds with 1,2,4-triazolo[1,5-a]pyrimidines, Me3Sn(5tpO) (1), n-Bu3Sn(5tpO) (2), Me3Sn(mtpO) (3), n-Bu3Sn(mtpO) (4), n-Bu3Sn(HtpO2) (5), Ph3Sn(HtpO2) (6) where 5HtpO = 4,5-dihydro-5-oxo-[1,2,4]triazolo-[1,5-a]pyrimidine, HmtpO = 4,7-dihydro-5-methyl-7-oxo-[1,2,4]triazolo-[1,5-a]pyrimidine, and H2tpO2 = 4,5,6,7-tetrahydro-5,7- dioxo-[1,2,4]triazolo-[1,5-a]-pyrimidine, was assessed on three different human tumor cell lines: HCT-116 (colorectal carcinoma), HepG2 (hepatocarcinoma) and MCF-7 (breast cancer). While 1 and 3 were inactive, compounds 2, 4, 5 and 6 inhibited the growth of the three tumor cell lines with IC50 values in the submicromolar …
The Co‐mutational Spectrum Determines the Therapeutic Response in Murine FGFR2 Fusion‐Driven Cholangiocarcinoma
2021
Background and aims Intrahepatic cholangiocarcinoma (ICC) is the second most common primary liver cancer and a highly lethal malignancy. Chemotherapeutic options are limited, but a considerable subset of patients harbors genetic lesions for which targeted agents exist. Fibroblast growth factor receptor 2 (FGFR2) fusions belong to the most frequent and therapeutically relevant alterations in ICC, and the first FGFR inhibitor was recently approved for the treatment of patients with progressed, fusion-positive ICC. Response rates of up to 35% indicate that FGFR-targeted therapies are beneficial in many but not all patients. Thus far, no established biomarkers exist that predict resistance or r…