scholarly journals Cyclin-dependent kinase inhibitor 1B (CDKN1B) gene variants in AIP mutation-negative familial isolated pituitary adenoma kindreds

2012 ◽  
Vol 19 (3) ◽  
pp. 233-241 ◽  
Author(s):  
Maria A Tichomirowa ◽  
Misu Lee ◽  
Anne Barlier ◽  
Adrian F Daly ◽  
Ilaria Marinoni ◽  
...  

Familial isolated pituitary adenoma (FIPA) occurs in families and is unrelated to multiple endocrine neoplasia type 1 and Carney complex. Mutations inAIPaccount only for 15–25% of FIPA families.CDKN1Bmutations cause MEN4 in which affected patients can suffer from pituitary adenomas. With this study, we wanted to assess whether mutations inCDKN1Boccur among a large cohort ofAIPmutation-negative FIPA kindreds. Eighty-eightAIPmutation-negative FIPA families were studied and 124 affected subjects underwent sequencing ofCDKN1B. Functional analysis of putativeCDKN1Bmutations was performed usingin silicoandin vitroapproaches. GermlineCDKN1Banalysis revealed two nucleotide changes: c.286A>C (p.K96Q) and c.356T>C (p.I119T).In vitro, the K96Q change decreased p27 affinity for Grb2 but did not segregate with pituitary adenoma in the FIPA kindred. The I119T substitution occurred in a female patient with acromegaly. p27I119Tshows an abnormal migration pattern by SDS–PAGE. Three variants (p.S56T, p.T142T, and c.605+36C>T) are likely nonpathogenic becauseIn vitroeffects were not seen. In conclusion, two patients had germline sequence changes inCDKN1B, which led to functional alterations in the encoded p27 proteinsin vitro. Such rareCDKN1Bvariants may contribute to the development of pituitary adenomas, but their low incidence and lack of clear segregation with affected patients makeCDKN1Bsequencing unlikely to be of use in routine genetic investigation of FIPA kindreds. However, further characterization of the role ofCDKN1Bin pituitary tumorigenesis in these and other cases could help clarify the clinicopathological profile of MEN4.

2011 ◽  
Vol 30 (3) ◽  
pp. 889-897 ◽  
Author(s):  
Xiangrui Liu ◽  
Frankie Lam ◽  
Shenhua Shi ◽  
Peter M. Fischer ◽  
Shudong Wang

1996 ◽  
Vol 109 (6) ◽  
pp. 1565-1573
Author(s):  
R. Starr ◽  
F.L. Hall ◽  
M.J. Monteiro

An immunoprecipitation assay was used to identify protein kinases which are physically associated with neurofilaments (NF) in mouse brain extracts. Using this approach, we show that a cdc2-related kinase is associated with NF. The cdc2-related kinase was found to be distinct from cdk5 and the authentic cdc2 by a number of criteria. Firstly, it has a molecular mass on SDS-PAGE gels of 34 kDa, similar to that of cdc2, but differing from cdk5 (31 kDa). Secondly, it is not recognized by an antibody specific for cdk5. Thirdly, it is recognized by an antibody raised against the C-terminal region of authentic cdc2, but not by an antibody specific for the PSTAIRE motif. Using immunoblotting, we further show that the cdc2-related kinase copurifies with NF isolated from rat tissues. In vitro kinase assays further demonstrated that immunoprecipitated cdc2-related kinase phosphorylates recombinant NF-H protein. Phosphorylation of NF-H by the cdc2-like activity was not affected by 3 microM olomoucine but was inhibited by 10 microM of this kinase inhibitor. Phosphoamino acid analysis of in vitro phosphorylated NF-H indicates that the immunoprecipitated cdc2-related kinase phosphorylates serine residues.


2007 ◽  
Vol 27 (9) ◽  
pp. 3530-3541 ◽  
Author(s):  
Jun Zhan ◽  
John B. Easton ◽  
Shile Huang ◽  
Ashutosh Mishra ◽  
Limin Xiao ◽  
...  

ABSTRACT The cyclin-dependent kinase inhibitor p21Cip1 regulates multiple cellular functions and protects cells from genotoxic and other cellular stresses. Activation of apoptosis signal-regulating kinase 1 (ASK1) induced by inhibition of mTOR signaling leads to sustained phospho-c-Jun that is suppressed in cells with functional p53 or by forced expression of p21Cip1. Here we show that small deletions of p21Cip1 around S98 abrogate its association with ASK1 but do not affect binding to Cdk1, hence distinguishing between the cell cycle-regulating functions of p21Cip1 and its ability to suppress activation of the ASK1/Jun N-terminal protein kinase (JNK) pathway. p21Cip1 is phosphorylated in vitro by both ASK1 and JNK1 at S98. In vivo phosphorylation of p21Cip1, predominantly carried out by ASK1, is associated with binding to ASK1 and inactivation of ASK1 kinase function. Binding of p21Cip1 to ASK1 requires ASK1 kinase function and may involve phosphorylation of S98.


2010 ◽  
Vol 22 (1) ◽  
pp. 329
Author(s):  
C. L. V. Leal ◽  
S. Mamo ◽  
T. Fair ◽  
P. Lonergan

Once removed from the follicle, mammalian oocytes resume meiosis spontaneously and progress through breakdown of the germinal vesicle to the matured state at metaphase II. The ability to reversibly inhibit such meiotic resumption has been reported and is a potentially useful method for studying developmental competence acquisition in oocytes as well as in some cases allowing flexibility in an IVF system where oocytes are collected from distant locations or on different days. The aim of the present study was to determine the effect of temporary inhibition of meiotic resumption using the cyclin-dependent kinase inhibitor butyrolactone I (BLI) on gene expression in bovine oocytes. Immature bovine oocytes were recovered from the ovaries of slaughtered heifers at a commercial abattoir and assigned to 1 of 4 groups: (1) Control: immature oocytes were collected either immediately or (2) after IVM for 24 h in TCM-199 containing 10 ng mL-1 EGF and 10% (v/v) FCS, (3) Inhibited oocytes collected either 24 h after incubation in the presence of 100 μM BLI in TCM-199 with 3 mg mL-1 BSA or (4) after meiotic inhibition for 24 h followed by in vitro maturation. All cultures were carried out at 38.5°C under 5% CO2 in air and maximum humidity. For mRNA relative abundance analysis, cumulus cells were removed and pools of 10 denuded oocytes were snap frozen in liquid nitrogen and stored at -80°C until use. A total of 42 transcripts, previously reported to be related to cell cycle regulation and/or oocyte competence were evaluated by quantitative real time PCR. Differences in relative abundance were analyzed by ANOVA and Student’s t-test. The majority of transcripts were downregulated (P < 0.05) after IVM in control oocytes (23 out of 42) and the same pattern was observed in inhibited oocytes that were allowed to mature. Twelve transcripts remained stable (P > 0.05) after IVM in control oocytes; of these, only two (PTTG1 and INHBA) did not show the same pattern in inhibited and matured oocytes. Few genes (7) were upregulated after IVM in control oocytes (P < 0.05) and of these, three (PLAT1, RBP1, and INHBB) were not upregulated in inhibited oocytes after IVM. Inhibited oocytes showed similar levels of expression (P > 0.05) as immature control oocytes, except for two genes (LUM and INHBB), which were increased in these oocytes (P < 0.05). The expression profiles of cell cycle genes were mostly unaffected by the BLI treatment. The few genes affected were previously reported as competence-related and could be useful markers of oocyte competence following pretreatment. In conclusion, the changes occurring in transcript abundance during oocyte maturation in vitro were to a large extent mirrored following inhibition of meiotic resumption prior to IVM and subsequent release from inhibition and maturation. CLV Leal was supported by CNPq, Brazil (PDE 201487/2007-1); Supported by Science Foundation Ireland (07/SRC/B1156).


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Beyza Bulutoglu ◽  
Safak Mert ◽  
Camilo Rey-Bedón ◽  
Sarah L. Deng ◽  
Martin L. Yarmush ◽  
...  

Abstract CYP3A4, a cytochrome P450 enzyme regulated by the nuclear receptor PXR, is involved in most of the drug metabolizing pathways. Studying the regulation/induction of CYP3A4 and PXR is critical in toxicology and drug-drug interaction (DDI) studies. Primary human hepatocytes constitute the preferred in vitro platform for drug development efforts. However, they are expensive, scarce and heterogeneous. Hepatic cell lines, such as Huh7, could provide a cost-effective alternative, however, they express negligible amounts of CYP450s and PXR. In this study, we show that dinaciclib, a potent cyclin dependent kinase inhibitor, significantly increases the basal CYP3A4 and PXR levels in 24 hours. We also demonstrated that matured Huh7s can be used for drug induction studies, where CYP3A4, CYP1A2, CYP2C9, and CYP2C19 inductions were achieved following rifampicin treatment. More importantly, through a direct demonstration using amiodarone and rifampicin as model drugs, we showed that matured Huh7s present a suitable platform for DDI studies.


2015 ◽  
Vol 98 (3) ◽  
pp. 465-472 ◽  
Author(s):  
Daniela Cihalova ◽  
Martina Ceckova ◽  
Radim Kucera ◽  
Jiri Klimes ◽  
Frantisek Staud

2012 ◽  
Vol 303 (6) ◽  
pp. E708-E719 ◽  
Author(s):  
Giampaolo Trivellin ◽  
Henriett Butz ◽  
Juliette Delhove ◽  
Susana Igreja ◽  
Harvinder S. Chahal ◽  
...  

Abnormal microRNA (miRNA) expression profiles have recently been associated with sporadic pituitary adenomas, suggesting that miRNAs can contribute to tumor formation; miRNAs are small noncoding RNAs that inhibit posttranscriptional expression of target mRNAs by binding to target sequences usually located in the 3′-UTR. In this study, we investigated the role played by miR-107, a miRNA associated with different human cancers, in sporadic pituitary adenomas and its interaction with the pituitary tumor suppressor gene aryl hydrocarbon receptor-interacting protein ( AIP). miR-107 expression was evaluated in pituitary adenoma and normal pituitary samples using microRNA screen TLDA (TaqMan Low-Density Array) and RT-qPCR assays. We show that miR-107 expression was significantly upregulated in GH-secreting and nonfunctioning pituitary adenomas. We found that human AIP-3′-UTR is a target of miR-107 since miR-107 inhibited in vitro AIP expression to 53.9 ± 2% of the miRNA control in a luciferase assay and reduced endogenous AIP mRNA expression to 53 ± 22% of the miRNA control in human cells. However, we did not observe a negative correlation between AIP and miR-107 expression in the human tumor samples. Furthermore, we show that miR-107 overexpression inhibited cell proliferation in human neuroblastoma and rat pituitary adenoma cells. In conclusion, miR-107 is overexpressed in pituitary adenomas and may act as a tumor suppressor. We have identified and confirmed AIP as a miR-107 target gene. Expression data in human samples suggest that the expression of AIP and miR-107 could be influenced by a combination of tumorigenic factors as well as compensatory mechanisms stimulated by the tumorigenic process.


2018 ◽  
Vol 30 (7) ◽  
pp. 1002 ◽  
Author(s):  
Qing Guo ◽  
Long Jin ◽  
Hai-Ying Zhu ◽  
Xiao-Xu Xing ◽  
Mei-Fu Xuan ◽  
...  

In this study we examined the effects of JNJ-7706621, a cyclin-dependent kinase inhibitor, on the in vitro growth of pig embryos that had been produced either by parthenogenetic activation (PA) or somatic cell nuclear transfer (SCNT). A significantly higher percentage of PA embryos reached the blastocyst stage by Day 7 after exposure to 10 µM JNJ-7706621 for 4 h compared with embryos exposed to 5 µg mL−1 cytochalasin B for 4 h (P < 0.05). Similarly, the rate of Tyr15 phosphorylation of the complex of cyclin and p34cdc2 (CDK1) was significantly elevated in the JNJ-7706621-treated embryos compared with embryos exposed to cytochalasin B or non-treated controls (P < 0.05). In contrast, Thr161 phosphorylation of CDK1 was significantly lower in the JNJ-7706621-treated group compared with the cytochalasin B-treated as well as the non-treated group (P < 0.05). Similarly, the level of M-phase-promoting factor (MPF) in embryos was significantly lower in the JNJ-7706621-treated group compared with the cytochalasin B-treated and non-treated groups (P < 0.05). In addition, more SCNT embryos reached the blastocyst stage after treatment with JNJ-7706621 than following exposure to cytochalasin B (P < 0.05). In conclusion, these results reveal that exposure to 10 µM JNJ-7706621 for 4 h improves early development of PA and SCNT porcine embryos by suppressing the activity of CDK1 and a concomitant reduction in the level of MPF.


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