Animals ; Cell Proliferation ; Hepatic Stellate Cells ; Liver Cirrhosis/metabolism* ; Protein Tyrosine Phosphatase, Non-Receptor Type 6 ; Rats

OBJECTIVE: To investigate the phenotype and molecular mechanism of DCA on MDS cell model, and to study the response of chemotherapeutic medicines to MDS cells through multiple dimensions, such as cell proliferation, invasion, migration and apoptosis, thus revealing the molecular mechanism of DCA treatment of MDS and its relationship with SHP-1 gene methylation. METHODS: MTT assay was used to determine the survival rate of MDS cells after treated by different concentrations of DCA. The effect of DCA on the invasion and migration of MDS cells was detected by Transwell assay method. Apoplexin V-FITCPI was used to detect apoptosis, the MDS treatment on the mechanism of DCA was investigated by Western blot and Real-time PCR experiment. RESULTS: According to the experiment, it was found that tumor proliferation could be inhibited when MDS skm-1 cells was treated by DCA, and the absorbance was lower and the inhibitory effect was more obvious in the 2.0, 5.0 μmol/L DCA group than in the 0.5 μmol/L DCA group and the negative control group. Compared with the control group, the number of MDS skm-1 cells crossing through the transwell upper chamber was significantly decreased after DCA application. After treated with 0.5, 2.0 and 5.0 μmol/L DCA, the apoptosis rate of MDS cells was 4.54%, 9.31% and 16.58% respectively, while the apoptosis rate of the control group was 3.20%, which shows the apoptosis rate increased significantly with the concentration of DCA. After treatment of MDS cell lines with different concentration of DCA, the methylation status of SHP-1 gene was decreased with the increase of drug concentration, the expression of SHP-1 was increased, the expression of STAT3 was decreased and the level of phosphorylation was decreased. CONCLUSION By analyzing the phenotypic response of DCA treatment on MDS cells, it was found that interfere with MDS can be performed by inhibiting proliferation, metastasis, and inducing apoptosis in a dose-dependent way. It revealed that the molecular mechanism by DCA treatment can improve the methylation of SHP-1 gene and inhibit the expression of p-STAT3.
Apoptosis ; Cell Line ; Cell Line, Tumor ; Cell Proliferation ; Decitabine ; Humans ; Protein Tyrosine Phosphatase, Non-Receptor Type 6

OBJECTIVETo explore the effect of overexpression of SH2-containing tyrosine phosphatase 1 (SHP-1) on sensitivity of chronic myelogenous 1eukemia (CML) K562 cell line to imatinib and its related mechamism.

METHODSK562 cells were infected with the lentiviral plasmids containing the specified retroviral vector (pEX-SHP-1-puro-Lv105) or the mock vector (pEX-EGFP-puro-Lv105). The expression of SHP-1 in K562 cells treated with 0.2 µmol/L imatinib (IM) for 72 h was determined by Western blot. After transfection the CCK-8 assay was used to determine the proliferation of the tramfected K562 cells (K562(SHP-1) and K562(EGFP) cells) at 72 h after exposure to different doses of IM, the half inhibitary concentration (IC50) was calculated. The mechanisms of the overexpression effects of SHP-1 and IM on the proliferation in K562 cells was investigated, the BCR-ABL1 activity and the level of tyrosine phosphorylation of CrkL (pCrkL) was measured by flow cytometry; the Western blot was used to detect the expression and activity of these molecules controlling cell growth, including MAPK, AKT, STAT5 and JAK2.

RESULTSAfter exposure of K562 cells to 0.08 µmol/L IM for 72 h, there was no significant change of SHP-1 expression in K562 cells. After exposure to 0.2 µmol/L of IM for 72 h, the inhibitory rate of K562(SHP-1) group was higher than that of K562(EGFP) group (P < 0.05), indicating that overexpression of SHP-1 in K562 cells could enhance the proliferation inhtibition effect of IM on K562 cells. The IC50 of IM in K562(SHP-1) cells was the lower as compared with that of K562(EGFP) cells (P < 0.05) after exposure to different concentrations of IM for 72 h. The slope of K562(SHP-1) cells was the largest ranging 0.02 - 0.16 µmol/L of IM. Overexpression of SHP-1 and IM could inhibit the activity BCR-ABL1, MAPK, AKT, STAT5 and JAK2 signaling pathways in the K562 cell line and displayed a synergistic effect.

CONCLUSIONSHP-1 inhibits BCR-ABL1, MAPK, AKT, STAT5 and JAK2 signaling pathways in K562 cells, the overexpression of SHP-1 can enhance the sensitivity of K562 cells to IM.

Cell Proliferation ; Drug Resistance, Neoplasm ; Genetic Vectors ; Humans ; Imatinib Mesylate ; pharmacology ; K562 Cells ; drug effects ; Phosphorylation ; Protein Tyrosine Phosphatase, Non-Receptor Type 6 ; genetics ; metabolism ; Signal Transduction ; Transfection

OBJECTIVETo investigate the profile of promoter methylation and expression of SHP-1 gene in the progression of chronic myeloid leukemia (CML).

METHODSThe expression level of SHP-1 mRNA and protein in bone marrow or peripheral blood mononuclear cells from CML patients were detected by Western blot and SYBR Green-based qRT-PCR. The methylation status of SHP-1 were assessed by methylation-specific polymerase chain reaction (MSP) assay. K562 cells were infected with the lentiviral plasmids pEX-SHP-1-puro-Lv105 (K562-SHP-1) or pEX-EGFP-puro-Lv105 (K562-EGFP). The levels of proteins and phosphorylated proteins were detected by Western blot. qRT-PCR assay was used to test the level of BCR-ABL mRNA.

RESULTSThe relative levels of SHP-1 mRNA were sharply decreased in advanced stages CML compared to chronic phase (CP)-CML (0.79±0.37 vs 1.18±0.64, P= 0.009). The level of SHP-1 protein was lower in advanced stages CML compared to CP-CML (0.57±0.02 vs 1.02±0.04, P=0.039). The frequency of SHP-1 gene promoter methylation at selected loci in CP-CML was 23.8% (10/42), and the methylated regions were detected in all advanced CML samples (P<0.01). SHP-1 was stably transfected into K562 cells and selected with puromycin. Overexpression of SHP-1 inhibited the proliferation and induced the apoptosis of K562 cells, meanwhile leaded to G0/G1 phase arrest. After transfection, the level of BCR-ABL mRNA was not affected in K562-SHP-1 cells (1.32±0.34) compared to K562-EGFP cells (1.18±0.20, P=0.644), but overexpression of SHP-1 caused a slight decrease in BCR-ABL protein in K562-SHP-1 cells compared to K562 -EGFP cells (0.78±0.15 vs 1.27±0.24, P=0.040). Overexpression of SHP-1 resulted in a remarkable decrease in MYC protein, phosphorylated forms of JAK2, STAT5, Akt and MAPK. However, the un-phosphorylated forms of these molecules were not significantly affected.

CONCLUSIONDecreased expression of SHP-1 caused by aberrant promoter hypermethylation may play a key role in the progression of CML by dysregulation of BCR-ABL, Akt, MAPK, MYC, JAK2 and STAT5 signaling.

Apoptosis ; DNA Methylation ; Disease Progression ; Fusion Proteins, bcr-abl ; Humans ; Janus Kinase 2 ; K562 Cells ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive ; Leukocytes, Mononuclear ; Phosphorylation ; Protein Tyrosine Phosphatase, Non-Receptor Type 6 ; RNA, Messenger

This study was aimed to investigate the expression level of SHP-1 and C-kit genes in acute leukemia HL-60 cells and effect of 5-aza-CdR demethylation on expression of SHP-1 and C-kit genes. RT-PCR was used to detect the mRNA expression level of SHP-1 and C-kit mRNA in HL-60 cells of the drug-treated group and control group.The methylation specific PCR (MSP) was applied to measure the methylation status of SHP-1 and C-kit genes in HL-60 cells.The results showed that after being treated with 5-aza-CdR, the recovery of SHP-1 gene expression was observed in HL-60 cells in which SHP-1 mRNA originally was not expressed. Meanwhile, the high expression level of C-kit mRNA in HL-60 cells was decreased. When HL-60 cells were treated with 0, 0.5, 1.0, 2.0 µmol/L 5-aza-CdR, the demethylation effect was enhanced, the expression of SHP-1 mRNA displayed an ascending tendency, and the expression of C-kit mRNA showed an descending tendency in dose-dependent manner (P < 0.05) . It is concluded that the absence of SHP-1 mRNA expression in HL-60 cells and recovery of expression after treatment with 5-aza-CdR suggest that the hypermethylation of SHP-1 gene relates with pathogenesis of leukemia, and the abnormal increase of C-kit mRNA expression maybe exist in formation of leukemia. The effect of 5-aza-CdR on expression of SHP-1 and C-kit shows dose-dependency, the higher the 5-aza-CdR concentration, the higher the SHP-1 expression and the lower the C-kit expression, moreover, the effect of 5-aza-CdR shows time-dependency in specific concentration.The SHP-1 mRNA expression negatively correlates with C-kit mRNA expression, suggesting that the decrease or absence of SHP-1 expression in leukemia cells weakens the negative regulation on C-kit signaling pathway, thus plays a role in the formation of leukemia.
Azacitidine ; pharmacology ; DNA Methylation ; drug effects ; HL-60 Cells ; Humans ; Leukemia ; genetics ; metabolism ; Protein Tyrosine Phosphatase, Non-Receptor Type 6 ; genetics ; Proto-Oncogene Proteins c-kit ; genetics ; RNA, Messenger

This study was purposed to explore the effects of a methylation inhibitor arsenic trioxide (As2O3, ATO) and 5-Aza-2'-deoxycytidine (5-aza-CdR) on the expression of JAK-STAT signal transduction pathway in family members JAK3, TYK2 and hematopoietic cell phosphatase SHP-1 in chronic myeloid leukemia cell line K562 and their roles in pathogenesis of leukemia. The K562 cells were divided into 3 groups:single drug-treated group, combined 2 drugs-treated group, group without drug treatment as control. The concentration of 5-aza-CdR were 0.5, 1, 2 µmol/L; the concentration of ATO was 1, 2.5, 5 µmol/L; the concentration of combined drugs was ATO 1 µmol/L + 5-aza-CdR 0.5 µmol/L, ATO 2.5 µmol/L + 5-aza-CdR 1 µmol/L, and ATO 5 µmol/L + 5-aza-CdR 2 µmol/L. The K562 cells were treated with above-mentioned concentration of drugs for 24, 48 and 72 hours, then the total RNA of cells was extracted, the JAK3, TYK2 and SHP-1 expressions were detected by real-time quantitative-PCR. The results showed that after the K562 cells were treated with ATO and 5-aza-CdR alone and their combination, the expression of SHP-1 mRNA increased, the expressions of JAK3 mRNA and TYK2 mRNA decreased along with increasing of concentration and prolonging of time, displaying the concentration and time-dependency. The SHP-1 negatively related with JAK3 and TYK2. The effect of SHP-1 on JAK3 was significantly higher than that on TYK2. It is concluded that when the K562 cells are treated with ATO and 5-aza-CdR alone and their combination, the expression of SHP-1 is up-regulated and the expressions of JAK3, TYK2 are down-regulated in concentration-and time-dependent manners, moreover the ATO and 5-aza-CdR show synergies demethylation effect. The SHP-1 gene exert effect possibly through inhibiting the JAK/STAT pathway, the JAK3 is affected more than TYK2, the JAK3 may exert more important role in TAK/STAT pathway.
Arsenicals ; pharmacology ; Azacitidine ; administration & dosage ; analogs & derivatives ; pharmacology ; DNA Methylation ; Gene Expression Regulation, Leukemic ; drug effects ; Humans ; Janus Kinase 3 ; metabolism ; K562 Cells ; Oxides ; pharmacology ; Protein Tyrosine Phosphatase, Non-Receptor Type 6 ; metabolism ; TYK2 Kinase ; metabolism

OBJECTIVE: To study the radiation-sensitizing function and preliminary mechanism of paclitaxel in radiation-resistant nasopharyngeal carcinoma cells. METHOD: X-ray dose fractionated irradiation technology to build radiation-resistant subline of nasopharyngeal carcinoma; CNE-2S1 was treated with paclitaxel alone or combined with radiation therapy, while control group treated with radiation therapy; cell colony formation assay was used to observe sensitizing effect of paclitaxel on radiotherapy; flow cytometry analysis was used to analyze cell cycle distribution and apoptosis ratio of different treatment groups; immunoblotting was used to analyze SHP-1 expression levels of different treatment groups. RESULT: Nasopharyngeal carcinoma cells resistant to radiation was successfully established; cell colony formation assay showed that paclitaxel has obvious sensitizing effect on radiotherapy; FACS results showed that: CNE-2S1 treated by paclitaxel were arrested in G2M phase; paclitaxel and radiotherapy treatments significantly improved the CNE-2S1 apoptosis ratio; Western blot results showed that paclitaxel and combined radiotherapy can reduce the CNE-2S1 cells SHP-1 expression levels. CONCLUSION Paclitaxel enhanced radiation therapy for nasopharyngeal carcinoma cells resistant to radiation, and SHP-1 may be involved in this progress.
Apoptosis ; drug effects ; Carcinoma ; Cell Cycle ; drug effects ; Cell Line, Tumor ; Humans ; Nasopharyngeal Carcinoma ; Nasopharyngeal Neoplasms ; pathology ; Paclitaxel ; pharmacology ; Protein Tyrosine Phosphatase, Non-Receptor Type 6 ; metabolism ; Radiation Tolerance ; drug effects

This study was aimed to investigate the expression level of SHP-1 and C-kit genes in acute leukemia HL-60 cells and effect of inhibitor As2O3 demethylation on SHP-1 and C-kit genes expression. RT-PCR was used to detect the expression level of SHP-1 and C-kit mRNA in drug-treated cell group and control group. The methylation specific PCR (MSP) was applied to measure the methylation status of SHP-1 gene in HL-60 cells. The results showed that after being treated with As2O3 the recovery of SHP-1 gene expression was observed in HL-60 cells in which SHP-1 mRNA originally did not expressed, meanwhile the expression level of C-kit mRNA in HL-60 cells with high expression decreased. When HL-60 cells were treated with As2O3 of 1.0, 2.5, 5.0 µmol/L, the demethylation effects was enhanced, the expression of SHP-1 mRNA displayed an ascending tendency, and expression of C-kit mRNA showed an descending tendency in dose-dependent manner (P < 0.05). It is concluded that the absence of SHP-1 mRNA expression in HL-60 cells and recovery of expression after treatment with As2O3 suggest the hypermethylation of SHP-1 gene related with pathogenesis of leukemia, and the abnormal increase of C-kit mRNA expression maybe exist in formation of leukemia. The effect of As2O3 on expression of SHP-1 and C-kit shows dose-dependency, the higher the As2O3 concentration, the higher the SHP-1 expression and the lower the C-kit expression, moreover, the effect of As2O3 shows time-dependency in specific concentration. The SHP-1 mRNA expression negatively relates with C-kit mRNA expression, suggesting that the decrease or absence of SHP-1 expression in leukemia cells weakens the negative regulation on C-kit signaling pathway, thus plays a role in the formation of leukemia.
Arsenicals ; metabolism ; pharmacology ; DNA Methylation ; Gene Expression Regulation, Leukemic ; HL-60 Cells ; Humans ; Oxides ; metabolism ; pharmacology ; Protein Tyrosine Phosphatase, Non-Receptor Type 6 ; genetics ; Proto-Oncogene Proteins c-kit ; genetics

More and more studies have found that the occurrence of tumors are directly related to the abnormal expression of oncogene and antioncogene. If the antioncogene is mutated or absent, the function of cells will be weakened and inactivated, the cells will be duplicated repeatedly out of control, then will induce occurrence and metastasis of tumor. For example, SHP-1 tyrosine phosphatase, as an antioncogene, is a key negative regulator in signaling transduction of haematopoietic cells. The decrease and silence of SHP-1 play an important role in tumorigenesis. If the oncogene in leukemia patients lost the effect of negative regulation of antioncogene, the oncogene would be expressed abnormally high, such as the oncogene c-kit (an important member of the class III in the tyrosine kinase receptor family) in many kinds of leukemia cells expresses actively. Studies have shown that the high methylation of promoter region would induce the inactivation of tumor suppressor and active expression of oncogene, therefore, the restoring normal methylation of promoter region will contribute to restoration of normal gene expression, thus achieving the purpose of gene therapy for leukemia. In this article, the methylation, methylation abnormality and leukemia, methylation suppressors and therapy of leukemia are briefly reviewed.
DNA Methylation ; drug effects ; Humans ; Leukemia ; drug therapy ; metabolism ; Protein Tyrosine Phosphatase, Non-Receptor Type 6 ; metabolism

OBJECTIVETo explore the role of SHP-1 promoter methylation on the pathogenesis and progression in myelodysplastic syndromes (MDS) and its related mechanism.

METHODS63 MDS patients were divided into low-grade (LG) group and high-grade (HG) group according to IPSS score system. Bone marrow samples were collected. Methylation specific-PCR (MSP) were used to detect the status of SHP-1 promoter methylation in bone marrow (BM) samples from different risk MDS patients and MDS cell line, SKK-1. Western blot was used to detect signal transduction and activator of transcription (STAT3) activation in SKK-1 cell line and MDS patients.

RESULTSNo SHP-1 promoter methylation could be detected in healthy controls BM. Partially methylation was found in SKK-1 cell line. Methylation rate of SHP-1 gene promoter was found in BM of 24.2% of low-grade MDS patients and 63.3% of high-grade MDS patients, the difference between these two groups was statistically significant (P < 0.05); Patients were divided into different groups according to WHO subtype, chromosomal karyotype and blast cells in bone marrow, methylation rates of SHP-1 were significantly higher in RAEB-II, poor karyotype group and samples with 0.11-0.19 blast cells (P < 0.05); The phosphorylation protein of STAT3 was detected in SKK-1 cell line. The expression of phosphorylation STAT3 was significantly higher in HG group than in LG group (66.7% vs 18.2%) (P < 0.05). There was a significant correlation between SHP-1 promoter methylation and STAT3 phosphorylation.

CONCLUSIONAbnormal methylation of SHP-1 gene promoter might have tentative role in the pathogenesis and progression of MDS, which may be involved in STAT3 activation. Detection of SHP-1 promoter methylation may be helpful to evaluate the prognosis of MDS.

Adolescent ; Adult ; Aged ; Case-Control Studies ; Child ; DNA Methylation ; Female ; Humans ; Male ; Middle Aged ; Myelodysplastic Syndromes ; genetics ; metabolism ; Prognosis ; Protein Tyrosine Phosphatase, Non-Receptor Type 6 ; genetics ; metabolism ; STAT3 Transcription Factor ; metabolism ; Young Adult