Inhibition of Integrin αvß3-FAK-MAPK signaling constrains the invasion of T-ALL cells.

The role of adhesion receptor integrin αvß3 in T-ALL was unclear. Firstly, we performed quantitative real-time PCR to assess medullary expression of integrin ß3(ITGB3) in T-ALL patients and high ITGB3 expression was relevant with the central nervous system leukemia(CNSL) incidence. Decreasing of cell invasion was observed in Jurkat and Molt4 treated with integrin αvß3 specific antibody and inhibitor as well as cells with ITGB3 interference. Further, phosphorylation of FAK, cRAF, MEK and ERK decreased in cells with integrin αvß3 inhibition or interference. Invasion decreased in T-ALL cells treated with FAK and ERK inhibitors. In conclusion, inhibition of integrin αvß3 signals significantly limits the cell invasion of T-ALL cells.

High expression of PRPS1 induces an anti-apoptotic effect in B-ALL cell lines and predicts an adverse prognosis in Chinese children with B-ALL.

Phosphoribosyl pyrophosphate synthetase 1 (PRPS1) is closely associated with a number of diseases; however, its influence in B-cell acute lymphoblastic leukemia (B-ALL) and the potential molecular mechanisms involved remain unclear. The present study aimed to evaluate the expression of PRPS1 in Chinese children with B-ALL and to investigate the mechanism of action of PRPS1 in this disease. A Cell Counting Kit-8 (CCK-8) assay was performed to examine the proliferation of B-ALL Sup-B15 and Raji cells, and flow cytometric analysis was conducted to determine the cell cycle distribution and rate of apoptosis. The mRNA and protein expression levels of PRPS1, MYC proto-oncogene, bHLH transcription factor, cyclin E1, B-cell lymphoma-2 (Bcl-2), cyclin dependent kinase 2 and caspase-3 were detected by reverse transcription-quantitative polymerase chain reaction and western blot analysis, respectively. Elevated PRPS1 expression was associated with a high-risk stratification and poor prognosis in patients with B-ALL. Furthermore, overexpression of PRPS1 accelerated the growth of and inhibited apoptosis in Sup-B15 and Raji cells as well as increasing the expression of Bcl-2 to induce an anti-apoptotic effect in B-ALL cell lines. The results of the present study indicate that PRPS1 regulates multiple processes in B-ALL and may be an attractive therapeutic target.

[Effect of 4' -Hydroxywogonin on Proliferation and Apoptosis of Human Acute Lymphoblastic Leukemia Cells].

OBJECTIVE: To investigate the effect of 4' -hydroxywogonin on proliferation and apoptosis of human acute lymphoblastic leukemia SUP-B15 and Jurkat cells, and to analyze its possible mechanism. METHODS: SUP-B15 and Jurkat cells were cultivated in vitro and treated with different concentrations of 4' -hydroxywogonin, the inhibitory effect of 4' -hydroxywogonin on the proliferation of SUP-B15 and Jurkat cells was detected by CCK-8 method; the cell apoptosis was examined by the flow cytometry with Annexin V-APC/7-AAD donble staining; the expression of C-MYC, BCL-2 and cleaved caspase 3 in SUP-B15 and Jurkat cells were measured with Western blot. RESULTS: 4' -hydroxywogonin inhibited the proliferation of SUP-B15 and Jurkat cells in a dose-dependent manner (r=0.78, r=0.89), with IC50 value of (6.32± 0.53) µg/ml in SUP-B15 cells and (12.04± 0.42) µg/ml in Jurkat cells at 24 h. The early apoptotic rate of cell was also enhanced with the increase of 4' -hydroxywogonin concentrations. The results of Western blot showed that 4' -hydroxywogonin could down-regulate the expression of proliferation-related molecule C-MYC(P<0.01) and apoptosis-related molecule BCL-2(P<0.01), the expression of apoptosis-related molecule cleaved caspase 3 was up-regulate(P<0.01). CONCLUSION: 4' -hydroxywogonin shows the effects of anti-tumor by inducing cell apoptosis and inhibiting cell proliferation, its molecular mechanism maybe relate with down-regulation of C-MYC and BCL-2 expression and up-regulation of the cleaved caspase 3 expression.

[Expression of ß-integrin family members in children with T-cell acute lymphoblastic leukemia].

OBJECTIVE: To study the expression of ß-integrin family members in children with T-cell acute lymphoblastic leukemia (T-ALL) and their significance. METHODS: Quantitative real-time PCR analyses were performed to assess the expression levels of ß-integrin family members in bone marrow samples from 22 children with newly-diagnosed T-ALL and 21 controls (16 children with non-malignant hematologic disease and 5 healthy donors with bone marrow transplantation). Jurkat cells were treated with integrin inhibitor arginine-glycine-aspartate (Arg-Gly-Asp, RGD) peptide. The cell viability and apoptosis rate were determined by CCK8 assay and flow cytometry respectively. RESULTS: The mRNA levels of integrins ß2, ß3, and ß5 were significantly lower in children with T-ALL than in controls (P<0.05). In T-ALL patients, high integrin ß3 expression was associated with lower white blood cell counts (<100×109/L), minimal residual disease (MRD) positivity, and day 33 bone marrow negative remission (P<0.05). In T-ALL patients, higher integrin ß5 expression was associated with relapse of T-ALL (P<0.05). Based on survival curve analysis, higher integrin ß3 expression was related to lower event-free survival and overall survival rates. RGD peptide treatment inhibited the proliferation of Jurkat cells and increased their apoptosis rate (P<0.05). CONCLUSIONS: ß-Integrin may play a role in the occurrence and development of T-ALL by affecting cell proliferation and apoptosis. The expression of integrin ß5 is closely related to the risk of relapse of T-ALL. The expression of integrin ß3 is closely related the treatment response and prognosis of T-ALL.

[PRPS1 Expression in Children with Acute Leukemia and Its Clinical Significance].

OBJECTIVE: To investigate the correlation between the expression level of PRPS1 and the clinical characteristics in children with acute leukemia(AL). METHODS: Real-time quantitative RT-PCR and Western blot were used to detect the level of PRPS1 mRNA and protein expression in bone marrow samples from 176 patients diagnosed as AL (126 cases were newly diagnosed and 50 cases in complete remission), and its relevance with clinical indicators was statistically analyzed. The bone marrow samples from 21 children with non-malignant hematological disease were used as controls. RESULTS: (1)In B-ALL group, the level of PRPS1 mRNA in newly diagnosed patients were significantly higher than that in control and than that in complete remission patients (both P<0.0001). In T-ALL and AML group, differences was only observed between newly diagnosed patients and complete remission patients(both P<0.0001); (2)In B-ALL group, the expression level of PRPS1 increase with along risk enhancement (P<0.01), while no significant difference was observed in T-ALL (P>0.05). In AML patients, expression difference was shown between low risk group and high risk group(P<0.05); (3)High PRPS1 mRNA expression level were associated with high WBC counts and MRD positive in B-ALL patients (P=0.020, P=0.026, respectively); (4)Expression of NT5C2, an essential gene for relapse and drug resistance, was found to be positively correlated with PRPS1 expression in AL samples(P<0.05). CONCLUSION: High expression of PRPS1 is relevant factor of unfavourable prognosis in B-ALL children, which suggest PRPS1 may be a new indicator for prognosis of pediatric B-ALL and an index to guide individualized chemotherapy.