HSP90 is a molecular chaperone that increases the stability of client proteins. Cancer cells show higher HSP90 expression than normal cells because many client proteins play an important role in the growth and survival of cancer cells. HSP90 inhibitors mainly bind to the ATP binding site of HSP90 and inhibit HSP90 activity, and these inhibitors can be distinguished as ansamycin and non-ansamycin depending on the structure. In addition, the histone deacetylase inhibitors inhibit the activity of HSP90 through acetylation of HSP90. These HSP90 inhibitors have undergone or are undergoing clinical trials for the treatment of cancer. On the other hand, recent studies have reported that various reagents induce cleavage of HSP90, resulting in reduced HSP90 client proteins and growth suppression in cancer cells. Cleavage of HSP90 can be divided into enzymatic cleavage and non-enzymatic cleavage. Therefore, reagents inducing cleavage of HSP90 can be classified as another class of HSP90 inhibitors. We discuss that the cleavage of HSP90 can be another mechanism in the cancer treatment by HSP90 inhibition.
Acetylation ; Adenosine Triphosphate ; Binding Sites ; Drug Therapy ; Hand ; Heat-Shock Proteins ; Histone Deacetylase Inhibitors ; Hot Temperature ; Indicators and Reagents ; Molecular Chaperones ; Rifabutin

Gene Expression Regulation, Fungal ; Gene Silencing ; Heterochromatin ; metabolism ; Histone Chaperones ; genetics ; metabolism ; Saccharomyces cerevisiae ; genetics ; metabolism ; Saccharomyces cerevisiae Proteins ; genetics ; metabolism ; Transcriptional Elongation Factors ; genetics ; metabolism

Humans ; Models, Molecular ; Repressor Proteins ; chemistry ; metabolism ; Retinoblastoma-Binding Protein 4 ; chemistry ; metabolism

BACKGROUNDThe most typical cardiac abnormality is conotruncal defects (CTDs) in patients with 22q11 deletion syndrome (22q11DS). HIRA (histone cell cycle regulator) gene, as one of the candidate genes located at the critical region of 22q11DS, was reported as possibly relevant to CTD in animal models. This study aimed to analyze the level of expression of the HIRA gene in tetralogy of Fallot (TOF) patients and the potential DNA sequence variations in the promoter region.

METHODSThe messenger RNA (mRNA) expression was examined with quantitative real-time polymerase chain reaction in 39 myocardial tissues of the right ventricular outflow tract (RVOT) from TOF patients and 4 myocardial tissues of RVOT from noncardiac death children. The protein expression was detected using immunohistochemistry in 12 TOF patients and 4 controls. A total of 100 TOF cases and 200 healthy controls were recruited for DNA sequencing.

RESULTSThe mRNA and protein expressions of the HIRA gene in the myocardium of the TOF patients were both significantly lower as compared to the controls (P < 0.05). Five single nucleotide polymorphisms (SNPs), including g.4111A>G (rs1128399), g.4265C>A (rs4585115), g.4369T>G (rs2277837), g.4371C>A (rs148516780), and g.4543T>C (rs111802956), were found in the promoter region of the HIRA gene. There were no significant differences of frequencies in these SNPs between the TOF patients and the controls (P > 0.05).

CONCLUSIONThe abnormal lower expression of the HIRA gene in the myocardium may participate in the pathogenesis of TOF.

Alleles ; Cell Cycle Proteins ; genetics ; metabolism ; Female ; Genotype ; Histone Chaperones ; genetics ; metabolism ; Humans ; Immunohistochemistry ; In Vitro Techniques ; Male ; Myocardium ; metabolism ; Polymorphism, Single Nucleotide ; genetics ; RNA, Messenger ; genetics ; Real-Time Polymerase Chain Reaction ; Tetralogy of Fallot ; genetics ; metabolism ; Transcription Factors ; genetics ; metabolism

OBJECTIVETo investigate the effect of silencing SET gene on the biological characteristics of acute promyelocytic leukemia NB4-R1 cells.

METHODSThe expression vector of pGCSIL containing SET-shRNA were transfected into 293T cells by using other packaging plasmids. The supernatant of the 293T cells was harvested for lentivirus. The SET-shRNA lentiviral vector was transfected into acute promyelocytic leukemia NB4-R1 cells and a stably transfected cell line was established. Real-time quantitative PCR and Western blot were used to assay the silencing efficiency on SET gene and the expression of PP2A. The cell cycle distribution was tested by flow cytometry.

RESULTSThe expression of SET in experimental group statistically decreased as compared with that of the control group. The expression of PP2A was obviously raised at the level of mRNA and protein. The percentage of NB4-R1 cells in G0/G1 phase significantly increased, while the percentage of cells in S phase significantly decreased.

CONCLUSIONThe silencing gene in acute promyelocytic leukemia NB4-R1 cells using SET-shRNA lentiviral vector can increase the expression of PP2A and interfere of the cell cycle in NB4-R1 cells. This study has laid a experimental base for targed therapy of patients with acute promyelocytic leukemia.

Cell Cycle ; Cell Line, Tumor ; Gene Silencing ; Genetic Vectors ; HEK293 Cells ; Histone Chaperones ; genetics ; Humans ; Lentivirus ; Leukemia, Promyelocytic, Acute ; genetics ; pathology ; Protein Phosphatase 2 ; metabolism ; RNA, Messenger ; RNA, Small Interfering ; Transcription Factors ; genetics ; Transfection

OBJECTIVETo investigate the effect of RbAp48 knockdown on the migration and invasion of human cervical cancer cells and explore the mechanism.

METHODSA small interference RNA (siRNA) was used to knock down the expression of RbAp48 in MS751 cells. The changes in cell migration and invasion were evaluated using wound healing assay and Transwell assay, respectively, and the expressions of RbAp48, vimentin, N-cadherin, E-cadherin, Snail, Twist, MMP-2 and TIMP-2 were determined with Western blotting.

RESULTSAfter siRNA-mediated RbAp48 knockdown, MS751 cells showed a significantly reduced expression of RbAp48 with significantly suppressed cell migration and invasion (P<0.01). RbAp48 knockdown induced obvious down-regulation of the expressions of interstitial cell phenotype proteins vimentin, N-cadherin, and MMP-2 and up-regulation of epithelial cell phenotype proteins E-cadherin and TIMP-2, suggesting the inhibition of epithelial- mesenchymal transition of the cells. The expressions of Snail and Twist were significantly down-regulated in the cells following RbAp48 knockdown.

CONCLUSIONKnockdown of RbAp48 can significantly inhibit epithelial-mesenchymal transition and suppress the migration and invasion of cervical cancer cell line MS751, the mechanism of which may involve the down-regulation of Snail and Twist expressions.

Antigens, CD ; metabolism ; Cadherins ; metabolism ; Cell Line, Tumor ; Cell Movement ; Down-Regulation ; Epithelial-Mesenchymal Transition ; Female ; Gene Knockdown Techniques ; Humans ; Matrix Metalloproteinase 2 ; metabolism ; Neoplasm Invasiveness ; Nuclear Proteins ; metabolism ; RNA, Small Interfering ; Retinoblastoma-Binding Protein 4 ; genetics ; Snail Family Transcription Factors ; Tissue Inhibitor of Metalloproteinase-2 ; metabolism ; Transcription Factors ; metabolism ; Twist-Related Protein 1 ; metabolism ; Up-Regulation ; Uterine Cervical Neoplasms ; pathology ; Vimentin ; metabolism

OBJECTIVETo investigate the expression level of SET gene in patients with acute myeloid leukemia (AML) and evaluate its significance.

METHODSThe expression level of SET gene in 141 de novo AML patients was determined by real time quantitative PCR (RQ-PCR), and its relationship with the clinical features and outcomes of these patients were analyzed.

RESULTSSET gene transcript level was detected in 141 AML patients with the median expression level of 0.86(range 0.02-15.69). AML patients with higher SET gene expression had a higher level of white blood cell (WBC ≥ 100 × 10⁹/L) count than of lower SET gene expression ones (31.0% vs 11.4%, P=0.005). In the 136 patients who received treatment after diagnosis, higher SET gene expression group had lower complete remission rate (50.0%) than of lower expression cohort (73.5%) after two cycles of chemotherapy (P=0.005). Survival analysis showed that patients with higher SET gene expression had significantly shorter overall survival(OS) (10 months vs 22 months, P=0.001) and event-free survival (EFS) (2 months vs 14 months, P=0.005) than of lower SET gene expression ones. Multivariate COX regression analysis showed SET overexpression was an independent prognostic factor for OS. In the patients with the normal karyotype, higher SET expression group also had significantly shorter OS (12 months vs 35 months, P=0.010) and EFS (4 months vs 14 months, P=0.026) than of lower SET expression ones.

CONCLUSIONHigh expression of SET gene was associated with poor prognosis and might be a prognostic molecular marker of AML.

Disease-Free Survival ; Gene Expression Regulation, Neoplastic ; Histone Chaperones ; genetics ; Humans ; Leukemia, Myeloid, Acute ; genetics ; Prognosis ; Remission Induction ; Transcription Factors ; genetics

OBJECTIVETo explore the effect of RNA interference of human I2PP2A gene on the proliferation and apoptosis of retinoic acid-resistant human acute promyelocytic leukemia (APL) cell line NB4-R1.

METHODSDesigned and constructed a RNA interference lentiviral vector I2PP2A-shRNA which targeted against I2PP2A gene, then transfected it into NB4-R1 via polybrene mediation. The I2PP2A expression levels before and after transfection were detected by qRT-PCR and Western blot, respectively. Meanwhile, the proliferation and apoptosis rates of each group were determined by CCK-8 and flow cytometry assay. The protein expressions of caspase-8 and PARP were detected by Western blot.

RESULTSBoth qRT-PCR and Western blot data showed the I2PP2A expression level was significantly downregulated in the transfection group. The I2PP2A mRNA expression level decreased by (70.0 ± 9.6)% and (64.0 ± 6.2)% respectively, compared with blank control and negative control group, and the I2PP2A protein expression level showed a consistent trend. CCK-8 proliferation assay indicated the NB4-R1 cell proliferation rate in I2PP2A-shRNA transfection group significantly reduced compared to blank control group (P<0.05). Flow cytometry results showed that NB4-R1 apoptosis rate in I2PP2A-shRNA transfection group increased by (6.30 ± 0.67) times and (6.04 ± 0.56) times, respectively (P<0.01). After inhibition of I2PP2A, the total caspase-8 and total PARP expressions decreased by (44.0 ± 3.1)% and (57.0 ± 4.0)%, respectively; Meanwhile, the cleaved caspase-8 (p43) and cleaved PARP (p89) increased by (36.0 ± 2.5)% and (45.0 ± 4.8)%, respectively compared with blank control group (P<0.05).

CONCLUSIONI2PP2A gene silenced by RNA interference could inhibit the proliferation and promote the apoptosis of NB4-R1, which may be regulated through caspase-8-induced exogenous apoptosis pathway.

Apoptosis ; genetics ; Caspase 8 ; metabolism ; Cell Line, Tumor ; Cell Proliferation ; genetics ; Drug Resistance, Neoplasm ; Histone Chaperones ; genetics ; metabolism ; Humans ; Leukemia, Promyelocytic, Acute ; metabolism ; pathology ; RNA Interference ; Transcription Factors ; genetics ; metabolism ; Tretinoin ; pharmacology

Cell Line ; Cell Proliferation ; drug effects ; Dose-Response Relationship, Drug ; Histone Chaperones ; metabolism ; Humans ; Liver ; cytology ; Protein Interaction Maps ; Solvents ; administration & dosage ; toxicity ; Transcription Factors ; metabolism ; Trichloroethylene ; administration & dosage ; toxicity

This study was aimed to investigate the occurrence and clinical significance of the SET-NUP214 fusion gene in patients with T-cell acute lymphoblastic leukemia (T-ALL), analyse clinical and biological characteristics in this disease. RT-PCR was used to detect the expression of SET-NUP214 fusion gene in 58 T-ALL cases. Interphase FISH and Array-CGH were used to detect the deletion of 9q34. Direct sequencing was applied to detect mutations of PHF6 and NOTCH1. The results showed that 6 out of 58 T-ALL cases (10.3%) were detected to have the SET-NUP214 fusion gene by RT-PCR. Besides T-lineage antigens, expression of CD13 and(or) CD33 were detected in all the 6 cases. Deletions of 9q34 were detected in 4 out of the 6 patients by FISH. Array-CGH results of 3 SET-NUP214 positive T-ALL patients confirmed that this fusion gene was resulted from a cryptic deletion of 9q34.11q34.13. PHF6 and NOTCH1 gene mutations were found in 4 and 5 out of 6 SET-NUP214 positive T-ALL patients, respectively. It is concluded that SET-NUP214 fusion gene is often resulted from del(9)(q34). PHF6 and NOTCH1 mutations may be potential leukemogenic event in SET-NUP214 fusion gene.
Carrier Proteins ; genetics ; Chromosome Deletion ; Chromosomes, Human, Pair 9 ; genetics ; Gene Expression ; Histone Chaperones ; genetics ; Humans ; Mutation ; Nuclear Pore Complex Proteins ; genetics ; Oncogene Proteins, Fusion ; genetics ; Precursor T-Cell Lymphoblastic Leukemia-Lymphoma ; genetics ; Receptor, Notch1 ; genetics ; Reverse Transcriptase Polymerase Chain Reaction ; Transcription Factors ; genetics