[Potential Oncogenic Role of Genes in PLC Family on T-ALL Cell Lines by Suppression of Apoptosis].

OBJECTIVE: To explore the role of phospholipase C(PLC) family in the progression of acute T lymphoblastic leukemia (T-ALL). METHODS: The apoptosis of T-ALL cells was determined by Annexin V-PE/7-AAD staining after treatment of PLC inhibitor U73122 and Edelfosine. Cox regression and Kaplan-Meier were used to analyze the impact of PLC expressions on the event-free survival (EFS) of T-ALL patients. PLC expression in each subtype of T-ALL were analyzed by One-way ANOVA. The siRNA expression plasmids targeting the PLCß1, PLCγ1, PLCη1 gene were constructed, and T-ALL cells were infected with retrovirus packaging in HEK-293T cells. The mRNA and protein level were tested by RT-PCR and Western blot. RESULTS: P12-ICH and CCRF-CEM cell line were sensitive to U73122 and Edelfosine treatment, while Jurkat and MOLT4 were resistant to them. In the TARGET-ALL database, the prognosis of T-ALL patients with high expression of PLCß1, PLCγ1 and PLCη1 was poor, and PLCß1, PLCγ1, PLCη1 were unevenly distributed in T-ALL subtypes. PLCß1, PLCγ1 and PLCη1 maintained the survival of P12-ICH and CCRF-CEM cell lines, respectively, while they had no effect on the survival of MOLT4. CONCLUSION: PLCß1, PLCγ1 and PLCη1 can maintain the growth of T-ALL cell lines in vitro and promote the malignant progression of T-ALL, which are potential therapeutic targets.

S1P-S1PR3-RAS promotes the progression of S1PR3hi TAL1+ T-cell acute lymphoblastic leukemia that can be effectively inhibited by an S1PR3 antagonist.

TAL1+ T-cell acute lymphoblastic leukemia (T-ALL) is a distinct subtype of leukemia with poor outcomes. Through the cooperation of co-activators, including RUNX1, GATA3, and MYB, the TAL1 oncoprotein extends the immature thymocytes with autonomy and plays an important role in the development of T-ALL. However, this process is not yet well understood. Here, by investigating the transcriptome and prognosis of T-ALL from multiple cohorts, we found that S1PR3 was highly expressed in a subset of TAL1+ T-ALL (S1PR3hi TAL1+ T-ALL), which showed poor outcomes. Through pharmacological and genetic methods, we identified a specific survival-supporting role of S1P-S1PR3 in TAL1+ T-ALL cells. In T-ALL cells, TAL1-RUNX1 up-regulated the expression of S1PR3 by binding to the enhancer region of S1PR3 gene. With hyperactivated S1P-S1PR3, T-ALL cells grew rapidly, partly by activating the KRAS signal. Finally, we assessed S1PR3 inhibitor TY-52156 in T-ALL patient-derived xenografts (PDXs) mouse model. We found that TY-52156 attenuated leukemia progression efficiently and extended the lifespan of S1PR3hi TAL1+ T-ALL xenografts. Our findings demonstrate that S1PR3 plays an important oncogenic role in S1PR3hi TAL1+ T-ALL and may serve as a promising therapeutic target.

[The Effect of KRAS on Proliferation and Apoptosis of T-ALL Cell Lines].

OBJECTIVE: To investigate the function of RAS protein on the progression of the T-ALL cell lines in vitro. METHODS: The DNA of the T-ALL cells was purified then amplified the coding regions of three RAS genes (KRAS, NRAS, HRAS) by PCR reaction. After T-A cloning, the coding regions of KRAS, NRAS and HRAS were sequenced by Sanger Sequencing. The siRNA oligonucleotides were cloned into the pSEH-361 vector, which were then packaged into retroviral together with pAMPHO and pVSVG in the HEK-293T cells. The T-ALL cells were infected with the retrovirus. The gene expressions were detected by qRT-PCR and Western blot. The T-ALL cells were stained with Annexin V-PE/7-AAD and the apoptotic cells were detected by flow cytometry. The T-ALL cells were stained with Hoechst 33258, and the cell cycle distribution was determined by flow cytometry. The expression of cleaved-Caspase 3 was stained with antibody and observed with fluorescence microscope. RESULTS: For RAS genes, beside the Loucy and the P12-ICH cells harbored KRAS c.6187G>A (p.KRASG12D) homozygous mutant, no missense mutation of RAS was found in other T-ALL cells genome. The pan RAS inhibitor compound 3144 showed toxicity to all tested T-ALL cells, except PEER (IC50=47.916 µmol/L). Similarly, Tipifarnib induced apoptosis of multiple T-ALL cell lines except for the PEER cells (IC50=94.2265 µmol/L). After KRAS knock-down, the T-ALL cells showed significant apoptosis and an arrested cell cycle. CONCLUSION: The KRAS protein is vital for the progression of the T-ALL cells in vitro, it is a potential therapeutic target for T-ALL patients.

[Application of Flow Cytometry Combined Fluorescence in Situ Hybridization to Indentify the Lymphocyte Subtypies with Epstein-Barr Virus Infection].

OBJECTIVE: To establish the technique that take the advantages of flow cytometry combined fluorescence in situ hybridization (Flow-FISH) to identify the Epstein-Barr virus(EBV) infected lymphocyte subtypies in patients' peripheral blood sample. METHODS: Peripheral Blood monocyte from 9 patients with EBV infection enrolled at Children's Hospital in Chongqing Medical University were isolated by Ficoll-paque centrifugal separation. The expressions of EBER1, EBER2 in cell were detected by qRT-PCR. The surface markers of cell were detected by Flow cytometry after staining with their antibodies. The cell was treated Fix-Permeabilization Buffer before hybridization with fluorescent labeled probe at 37 ℃ overnight. The cell status, surface markers and targeted mRNA are detected by flow cytometry and fluorescence microscope. RESULTS: It was optimized that the Fix-Permeabilization Buffer and recipe with 0.2% Tween-20 were picked out as providing a good cell integrity and high resolution of surface markers. Hybridization with 20% formamide and 7% dextran sulfate at 37 ℃ overnight is the optimal hybridization condition as a good hybridization effect, a detectable cell integrity and a high resolution of cell markers under flow cytometry detection. Finally, upon the established Flow-FISH method, lymphocyte subpopulations of the EBV+ cells from cell lines and blood samples of patients were identified successfully. CONCLUSION: A Flow-FISH technology is established, which can be applied in the identification of EBV infected cell subtypes. This research provides a foundmental for its application in clinical test in EBV+ related proliferative diseases.

MiR-652-5p elevated glycolysis level by targeting TIGAR in T-cell acute lymphoblastic leukemia.

The effect of glycolysis remains largely elusive in acute T lymphoblastic leukemia (T-ALL). Increasing evidence has indicated that the dysregulation of miRNAs is involved in glycolysis, by targeting the genes coding glycolysis rate-limiting enzymes. In our previous studies, we found that overexpression of the ARRB1-derived miR-223 sponge repressed T-ALL progress and reduced the expression of miR-652-5p. However, little is known about miR-652-5p on T-ALL. Here, we showed that impaired miR-652-5p expression inhibited growth, promoted apoptosis of T-ALL cells in vitro and prolonged overall survival (OS) in vivo. Based on the GO enrichment of miR-652-5p target genes, we uncovered that impaired miR-652-5p decreased glycolysis, including reduced the lactate, pyruvate, ATP level and the total extracellular acidification rate (ECAR), elevated oxygen consumption rate (OCR) in T-ALL cell lines. Mechanically, miR-652-5p targeted the 3'UTR of Tigar mRNA and inhibited its expression. Furthermore, the alteration of glycosis level was attributed to Tigar overexpression, consistent with the effect of impaired miR-652-5p. Additionally, Tigar suppressed the expression of PFKFB3, a glycolysis rate-limiting enzyme, in vivo and in vitro. Taken together, our results demonstrate that impaired miR-652-5p/Tigar axis could repress glycolysis, thus to slow growth of T-ALL cells, which support miR-652-5p as a novel potential drug target for T-ALL therapeutics.