ABSTRACT
@#【Objective】To study the expression of Tip60（KAT5）in Oral squamous cell carcinoma（OSCC），and to investigate the relationship of Tip60（KAT5）and OSCC.【Methods】Forty-nine samples of OSCC and 36 samples of nor⁃ mal tissue adjacent to OSCC were collected and analyzed retrospectively. The expression of Tip60（KAT5）was detected by immunehisto chemistry using Envision detection system. OSCC cell line Cal27 and UM1 cultured in vitro were treated with Nu9056，an inhibitor of Tip60（KAT5）for 24h，respectively. Then the effect of different concentrations and times on the growth of Cal27 and UM1 cells was evaluated with MTT assay.【Results】The expression of Tip60（KAT5）in OSCC was significantly higher than that in normal tissue adjacent to OSCC（P=0.000）. Its expression was significantly positively correlated with the degree of histological differentiation（r=0.461，P=0.001）. With the increase of concentration，the proliferation inhibition rate of Nu9056 on Cal27 and UM1 cells gradually increased，showing a concentration- dependent and time-dependent relationship（P<0.05）.【Conclusions】The expression of Tip60（KAT5）protein in oral squamous cell carcinoma tissues was related to the degree of histological differentiation ，Tip60（KAT5）can be used as oral squamous cell carcinoma progression and prognosis of biological indicators.
ABSTRACT
The Aurora kinases represent a group of serine/threonine kinases which are crucial regulators of mitosis. DysregulatedAurora kinase B (AurkB) expression, stemming from genomic amplification, increased gene transcription or overexpressionof its allosteric activators, is capable of initiating and sustaining malignant phenotypes. Although AurkB level in cells iswell-orchestrated, studies that relate to its stability or activity, independent of mitosis, are lacking. We report that AurkBundergoes acetylation in vitro by lysine acetyltransferases (KATs) belonging to different families, namely by p300 andTip60. The haploinsufficient tumor suppressor Tip60 acetylates two highly conserved lysine residues within the kinasedomain of AurkB which not only impinges the protein stability but also its kinase activity. These results signify a probableoutcome on the increase in ‘‘overall activity’’ of AurkB upon Tip60 downregulation, as observed under cancerous conditions. The present work, therefore, uncovers an important functional interplay between AurkB and Tip60, frailty of whichmay be an initial event in carcinogenesis.
ABSTRACT
UHRF2 is a ubiquitin-protein ligase E3 that regulates cell cycle, genomic stability and epigenetics. We conducted a co-immunoprecipitation assay and found that TIP60 and HDAC1 interact with UHRF2. We previously demonstrated that UHRF2 regulated H3K9ac and H3K14ac differentially in normal and cancer cells. However, the accurate signal transduction mechanisms were not clear. In this study, we found that TIP60 acted downstream of UHRF2 to regulate H3K9ac and H3K14ac expression. TIP60 is stabilized in normal cells by UHRF2 ubiquitination. However, TIP60 is destabilized in cancer cells. Depletion or inhibition of TIP60 disrupts the regulatory relationship between UHRF2, H3K9ac and H3K14ac. In summary, the findings suggest that UHRF2 mediated the post-translational modification of histones and the initiation and progression of cancer.
Subject(s)
Humans , Cell Line , Histone Acetyltransferases , Genetics , Metabolism , Histones , Genetics , Metabolism , Lysine Acetyltransferase 5 , Neoplasm Proteins , Genetics , Metabolism , Neoplasms , Genetics , Metabolism , RING Finger Domains , Ubiquitin-Protein Ligases , Genetics , Metabolism , UbiquitinationABSTRACT
Objective To investigate the effect of Tip60 on the cellular radiosensitivity,and to explore the related mechanism.Methods siRNA and anacardic acid (AA,an inhibitor of Tip60 acetyltransferase) were used to inhibit Tip60 expression and its acetyltransferase activity,respectively.Radiosensitivity was analyzed by colony-forming ability assay.γ-H2AX foci were detected to analyze the DNA double-strand break (DSB).Immunoprecipitation was used to determine the interaction of proteins.Results siRNA-mediated silencing of Tip60 led to enhanced sensitivity of U2OS cells at 1,2 Gy after γ-ray irradiation,but had no significant effect at 4 Gy post-irradiation ( t =3.364,3.979,P ＜ 0.05 ).γ-H2AX foci detection indicated that Tip60 silencing resulted in a decreased capability of DNA doublestrand break repair at 1,4 and 8 h after irradiation( t =3.875,3.183 and 3.175,respectively,P ＜ 0.05 ).The interaction of Tip60 and DNA-PKcs was prompted by ionizing radiation.Anacardic acid largely abrogated the phosphorylation of DNA-PKcs at T2609 site induced by irradiation.Conclusions Tip60plays a role in the cellular response to ionizing radiation-induced DNA damage through,at least in part,interacting with DNA-PKcs and regulating its phosphorylation.
ABSTRACT
Objective To construct a yeast expression vector containing human TIP60? gene (a spliced form of HIV-1 tat interactive protein,HTATIP,60?103) and screen its interaction proteins by yeast two-hybrid. Methods Human TIP60? gene fragment was amplified by RT-PCR and cloned into pGBKT7 vector. Using TIP60? as bait,the proteins interacting with TIP60? were screened from a human liver cDNA library. The positive clones were analyzed by bioinformatic methods. Results Human TIP60? cDNA was successfully amplified and cloned into the pGBKT7 vector and indentified by double enzyme digestion and DNA sequencing. Using yeast two-hybrid,32 clones were screened from a human liver cDNA library,and 9 positive clones including histone deacetylase 7A (HDAC7A),mouse double minute 2 (DMD2),B-cell CLL/lymphoma 3 (BCL3),endothelin receptor type A (EDNRA),androgen receptor (AR),PHD finger protein 17 (PHF17),Ataxia Telangiectasia Mutated (ATM),CAMP responsive element binding protein 1 (CREB1),orphan steroid receptor BD73 were verified after sequencing. Conclusion The screened interaction proteins with TIP60? by yeast two-hybrid may be involved in the roles of transcriptional regulation of TIP60?.