Acute Lymphoblastic Leukemia Jurkat Research Articles

Synergistic combination of isogarcinol isolated from edible fruits of Garcinia multiflora and dexamethasone to overcome leukemia glucocorticoid resistance

Isogarcinol (ISO), a cytotoxic polycyclic polyprenylated acylphloroglucinol isolated from the edible fruits of Garcinia multiflora. However, synergistic combination of ISO and dexamethasone (DEX) to overcome leukemia glucocorticoid resistance has never been investigated. Therefore, in this study, the effects of ISO in combination with DEX was conducted on leukemia in vivo and glucocorticoid resistance in vitro. As a result, the combination of the two compounds could efficiently inhibit leukemia progression in mice and reverse DEX resistance in acute lymphoblastic leukemia (ALL) Jurkat cells. Significantly, our findings indicated that c-Myc may be a potential target of ISO, as it is involved in cell cycle arrest and apoptosis by the combination of ISO and DEX in Jurkat cells. Furthermore, western blot analysis revealed that ISO and DEX inhibits the PI3K/Akt/mTOR signaling pathway and promotes the nuclear translocation of glucocorticoid receptor (GR), which activates target genes NR3C1 and TSC22D3, leading to apoptosis in Jurkat cells. Hence, our results suggest that ISO, as a safe and effective food-derived agent, can enhance the anti-leukemia effects of DEX.

Apoptosis inhibition in T-cell acute lymphoblastic leukemia by UNC13B

T-cell acute lymphoblastic leukemia is a type of leukemia that is difficult to treat and has a complex pathogenesis, with no effective treatment currently available. This research group found that the mRNA expression of a new gene, UNC13B, was increased in T-cell acute lymphoblastic leukemia patients. Subsequently, we used T-cell acute lymphoblastic leukemia Jurkat cells to study the mechanism of UNC13B. We constructed a lentiviral vector expressing siRNA to target UNC13B and transfected it into the T-cell acute lymphoblastic leukemia Jurkat cell line. Using CCK-8, flow cytometry, and western blotting analyses, we found that knockdown of UNC13B inhibited the growth of T-cell acute lymphoblastic leukemia Jurkat cells via the downregulation of signaling proteins of the cell proliferation pathway and upregulation of apoptosis signaling proteins. Based on the bioinformatics analysis results, we found that the mechanism of UNC13B responsible for promoting the growth of T-cell acute lymphoblastic leukemia can be experimentally achieved by triggering AK2, MAP3K7, and PINK1. This study demonstrates that UNC13B is a new potential target for T-cell acute lymphoblastic leukemia.

Bovine serum albumin protected gold nanozymes as a novel anti-cancer nanodrug for acute T-type lymphoblastic leukemia treatment via effect on the expression of anti-apoptotic genes

In this paper, the bovine serum albumin protected gold nanozymes (BSA-Au nanozymes) were utilized as a novel nanodrug for treatment of acute T-type lymphoblastic leukemia (Jurkat) by production of excessive ROS and effect on the expression of anti-apoptotic genes. The effect of BSA-Au nanozymes on the Bcl-2 expression and survivin in the Jurkat cell line was checked. The results showed that the expression of anti-apoptotic genes was significantly reduced after treatment of the Jurkat cell line with the BSA-Au nanozymes (p-value of 0.001) as the potential nanodrug while their expression in the normal PBMC was not affected by the nanodrug. Moreover, the cytotoxic effect of the developed nanodrug on the Jurkat cell line was evaluated which illustrated that survival rate in the studied cell line reaches its minimum value (100% lethality, 0.0% survival) after treatment for 48 h. The IC50 for the nanodrug was calculated at 0.05 mM of the developed nanodrug. Overall, the BSA-Au nanozymes can be used as the nanodrug for treatment of T-type lymphoblastic leukemia via reducing the expression of anti-apoptotic genes, increasing the effect of common anticancer drugs such as Adriamycin and ara-C, and consequently increasing the survival of patients with leukemia.

Antibacterial and antitumoral properties of 1,2,3-triazolo fused triterpenes and their mechanism of inhibiting the proliferation of HL-60cells.

Antimicrobial resistance and cancer are two important problems affecting human health. Actively developing novel antibiotics and anticancer medicines is a priority. Natural pentacyclic triterpenoids have attracted wide attention due to their significant biological activities. In this study, a series of 1,2,3-triazolo fused triterpenoids (betulin, oleanolic acid and ursolic acid) were functionalized on the A-ring by an in-house developed multi-component triazolization reaction. The compounds were investigated for antitumoral activity in twelve cancer cell lines and were also tested for antibacterial activity against four bacteria. In terms of anticancer effects, compounds 5b-f and 8a-d displayed strong cytotoxic activity in pancreatic adenocarcinoma (Capan-1), chronic myeloid leukemia (Hap-1), acute myeloid leukemia (HL-60), acute lymphoblastic leukemia (Jurkat) and non-Hodgkin lymphoma (Rec-1) cell lines. Among them, compound 5f exhibited the most potent antiproliferative effect on HL-60cells. Further pharmacological research confirmed that compound 5f caused mitochondrial dysfunction and arrested the cell cycle in the G0/G1 phase to induce apoptosis of HL-60cells. In addition, compound 5f also induced autophagy to inhibit the proliferation of HL-60cells. Antibacterial screening revealed that compounds 2a-g and 5a-d showed modest activity against Gram-negative bacteria (Escherichia coli and Salmonella enterica subsp. enterica) with especially compounds 2c and 2d being potent inhibitors of Salmonella enterica subsp. enterica growth. Because of their promising anticancer and antibacterial activity, this series of compounds deserve further study.

Antineoplastic activity of free 4-nitrochalcone and encapsulated in poly(thioether-ester) nanoparticles obtained by thiol-ene polymerization in two human leukemia cell lines (Jurkat and K562)

Poly(thioether-ester) (PTEe), a polymer synthesized from renewable monomers, is a promising alternative for the encapsulation of antitumor drugs due to its biocompatibility and biodegradability. Therefore, the aim of this study was to synthesize, characterize and evaluate the cytotoxicity of free 4-nitrochalcone (4NC) and 4NC encapsulated in PTEe nanoparticles prepared by thiol-ene miniemulsion polymerization in chronic myeloid leukemia in blast crisis (K562) and acute lymphoblastic leukemia (Jurkat) and peripheral blood mononuclear cells. 4NC was successfully encapsulated in PTEe nanoparticles with an encapsulation efficiency >90%, a mean size of 110 nm, negative surface charge and extended-release profile. Free 4NC and encapsulated in PTEe nanoparticles presented a significant cytotoxicity on K562 and Jurkat cells. Also, 4NC encapsulated in PTEe nanoparticles presented lower damage to peripheral blood mononuclear cells, providing a higher selectivity index than free 4NC for chronic myeloid leukemia in blast crisis (K562) and acute lymphoblastic leukemia (Jurkat). Considering the difficulties involved in leukemia treatment and good results obtained with free 4NC and encapsulated in PTEe nanoparticles, these results can be a new tool for the treatment of neoplastic cells.

Combination therapy with miR-34a and doxorubicin synergistically induced apoptosis in T-cell acute lymphoblastic leukemia cell line.

MicroRNAs are identified to take actively part in the development of different cancers. Reduced expression of tumor suppressor miRNAs leads to cancer cell development, so restoring the expression of these miRNAs can be an appropriate treatment option for cancer. Due to the heterogeneity of cancer cells, single-drug therapy often results in drug resistance. Therefore, the combination of chemotherapy with miRNA can be a powerful strategy for cancer treatment. In the current investigation, miR-34a mimic, and negative control were purchased and transfected using jetPEI reagents. Then the synergic effects of miR-34a in combination with doxorubicin were investigated on cell death of acute T-cell lymphoblastic leukemia Jurkat cell line, as well as the expression of some genes including Caspase-3, Bcl-2, and p53 which are involved in apoptosis. Our outcomes showed that this combination remarkably reduced the expression of the Bcl-2 gene, the target gene of miR-34a. According to the results of the MTT assay, the survival rate was significantly decreased compared to the untreated cells. Results of the flow cytometry assay and DAPI staining demonstrated an increased apoptosis rate of Jurkat cells in combination therapy. Moreover, cell cycle arrest was observed at the G2/M phase in cells that were treated with miR-34a/doxorubicin. Most importantly, we showed that the transfection of the Jurkat cells with miR-34a increased the sensitivity of these cells to doxorubicin. Furthermore, the combination of miR-34a and doxorubicin drug effectively increased apoptosis of treated cells. Therefore, this method can be used as an impressive treatment for T-ALL.

Pharmacokinetic properties and anti-proliferative mechanisms of vanillin against acute lymphoblastic leukemia (Jurkat) cells

The anti-proliferative potential of vanillin isolated from an ethnomedicine Flacourtia indica bark was evaluated in an acute lymphoblastic leukemia cell line (Jurkat) in our previous study, but its molecular mechanisms of action are not yet revealed. The present work investigated the pharmacokinetic properties & cellular uptake of vanillin, in addition to evaluating the effect of vanillin treatment on cell morphology, mitochondrial membrane potential, DNA fragmentation, and cell survival & pro-apoptotic proteins in Jurkat cells. High absorption, good oral bioavailability, and safety of vanillin were recorded through in silico pharmacokinetic studies. In vitro study results indicate that 24.07% of vanillin was absorbed by Jurkat cells within 120 min. The IC50 dose of vanillin reduced the mitochondrial membrane potential up to 77.05% and also caused 60.94% of DNA fragmentation in Jurkat cells. Further, inhibition of cell survival proteins such as H-RAS, K-RAS, N-RAS, & BCL-2 and activation of pro-apoptotic proteins like p-38, BAX, pro-caspase-9, pro-caspase-3, and caspase-3 by vanillin was confirmed through molecular docking and western blotting studies. Thus, the current study revealed the pharmacokinetic properties and anti-proliferative mechanisms of vanillin in Jurkat cells. Therefore vanillin could be further investigated to develop a safe and alternative phytopharmaceutical to treat acute lymphoblastic leukemia.

Targeting Itch/p73 pathway by thymoquinone as a novel therapeutic strategy for cancers with p53 mutation

The tumor suppressor p73 is a member of p53 family and has a high degree of similarity with p53 function and structure. Like p53, p73 can also induce the expression of several genes involved in cell cycle and apoptosis. p73 expression is downregulated in many tumors by several mechanisms including the ubiquitination pathway. Thus, understanding the ubiquitin-proteasome pathway in p73 regulation will help in targeting this later and develop a new promising therapeutic strategy for cancer with p53 mutations. The aim of this study was to evaluate the effect of Thymoquinone (TQ), the major biologically active compound of the black seed oil on the expression of several E3 ubiquitin ligase enzymes known to be regulators of p73 and the related events in cancer cells with p53 mutation, such as the human acute lymphoblastic leukemia Jurkat cells, the human triple-negative breast cancer (MDA-MB-468 cells) and human promyelocytic leukemia HL60 cells. RNA-seq data showed that several E3 ubiquitin-ligase enzymes, well documented to be involved in the degradation of p73 including Itch, Pirh2, E3s Pin2, Mdm2, TRIM32 and SCFFBXO45 were downregulated in Jurkat cells. Among the target genes, Itch was significantly downregulated in TQ-treated Jurkat cells as compared with control cells. TQ-induced Itch downregulation was confirmed by real-time RT-PCR in Jurkat cells, MDA-MB-468 cells and HL60. Treating Jurkat cells with either TQ or the proteasome inhibitor MG132 induced an upregulation of p73. The present study indicates that TQ could be a promising inhibitor of the E3-ubiquitin ligase Itch leading to the upregulation of tumor suppressor p73 in cancers expressing mutant p53.

COMPARISON OF CYTOTOXIC ACTIVITY OF CISPLATIN AND A CLUSTER RHENIUM(III) COMPOUND

Due to the earlier data about anticancer activity of the cluster rhenium(III) compounds and their synergism with cisplatin, the comparison investigations of influence of this compounds with cisplatin on the human leukemic cells is of great interest. The aim of the work was to compare the cytotoxic activity of the cluster rhenium compound Re2Cl2(C3H7CO2)4(I) in the solutions and nanoliposomes alone and together with cisplatin in Jurkat cells. Cytotoxicity of the substances were investigated against T-cells of acute lymphoblastic leukemia (Jurkat cells) by conventional methods. We have shown that the cytotoxic activity of I and cisplatin was close and the cytotoxic activity of the rhenium-platinum system was much more effective than that of I and cisplatin. In the range of low concentrations I is more effective in solutions than cisplatin that may be the explanation of much lower toxicity of the rhenium compounds and their efficacy in experiments in vivo. Liposomal formulations of investigated preparations are more effective than their solutions, due to a simplified transport mechanism and prevention of the deactivation before penetration to the cancer cell. Liposomal I and antitumor system on its base have LC50 in the range of10-8 M, that is comparable with the LC50 values for the known antitumor drugs and underlines the importance of further investigations of the rhenium cluster compounds as anticancer species. The obtained results underline perspectives of the use of dirhenium compounds in medicines and emphasize the need of further investigations of mechanisms of anticancer activity of the cluster dirhenium(III) compounds. Keywords: cluster rhenium compound; rhenium-platinum antitumor system; cytotoxic activity; apoptosis.

Dihydroartemisinin Induces Apoptosis of Human Acute T Lymphocytic Leukemia Cells by Activating Oxidative Stress

To investigate the effects of dihydroartemisinin (DHA) on the proliferation and apoptosis of human T-cell acute lymphoblastic leukemia (T-ALL) Jurkat cell. The effects of DHA on the proliferation of Jurkat cells and the recovery of DHA-inhibited cell viability by N-acetyl-L-cysteine (NAC) were examined by CCK-8 assay. Flow cytometry was performed to analyze the cell apoptosis and generation of reactive oxygen species (ROS). Western-blot was used to detected protein expression of DNA damage-related genes, as well as apoptosis-associated genes, respectively. DHA inhibited the proliferation of Jurkat cells, and shows a concentration-dependent manner(r =0.936), and NAC could partially restore the activity of DHA on cell proliferation inhibition. With the increase of drug concentration, the apoptosis rate (r =0.946) and ROS accumulation was increased (r =0.965). Western blot showed that the protein expressions of DNA damage-related gene γ-H2AX and apoptosis-related genes p53, c-Caspase3, BAX and cPARP were significantly increased, and BCL-2 protein expression was decreased. DHA can induce ROS production in Jurkat cells, which can cause DNA damage, activate the P53 apoptotic pathway, and promote apoptosis of cells.

Antiproliferative and apoptotic interaction between azathioprine and N-acetylcysteine in acute lymphoblastic leukemia Jurkat cells

Abstract T cell acute lymphoblastic leukaemia is a type of cancer that develops from lymphoid progenitors, and chemotherapy is corner stone of the treatment. Thiopurine drugs, consisting of 6-mercaptopurine, 6-thioguanine, and azathioprine (Aza), can effectively treat this disease. To be activated, Aza must first be biotransformed to 6-mercaptopurine by thiol groups in glutathione. However, glutathione is decreased in cancer cells due to high levels of reactive oxygen species (ROS). N-acetylcysteine could provide thiol groups for glutathione synthesis to biotransform Aza. Using flow cytometry, the ability of N-acetylcysteine to increase the antiproliferative and apoptotic effects of Aza without increasing ROS was tested in Jurkat cells. Individually, Aza 1.0 and 2.0 μM, as well as N- acetylcysteine 3.0 mM, induced apoptosis and cell cycle arrest. Together, Aza + N-acetylcysteine significantly reduced proliferation compared to that obtained with the individual drugs. Combination of N-acetylcysteine 3.0 mM with Aza 1.0 μM was as effective at inducing apoptosis as Aza 2.0 μM alone. The combination of N-acetylcysteine 3.0 mM + Aza 1.0 μM increased cell cycle arrest at the G2/M phase. We found that Aza 1.0 or 2.0 μM induced a significant increase in ROS compared to that in untreated cells, while N-acetylcysteine 3.0 mM and N-acetylcysteine 3.0 mM + Aza 1.0 μM kept ROS at control levels; the latter drugpairing represents a favourable combination to reduce oxidative stress in the presence of Aza. In conclusion, N-acetylcysteine augments antiproliferative and apoptotic effects of Aza without increasing ROS in vitro.

Enhancement of Quercetin-Induced Apoptosis by Cotreatment with Autophagy Inhibitor Is Associated with Augmentation of BAK-Dependent Mitochondrial Pathway in Jurkat T Cells.

A flavonoid antioxidant quercetin promotes dose-dependent activation of the ATM-CHK-p53 pathway, downregulation of antiapoptotic survivin, and upregulation of proapoptotic NOXA in human T cell acute lymphoblastic leukemia Jurkat clones (J/Neo and J/BCL-XL). However, the downregulation of antiapoptotic BAG3 and MCL-1 occurred in J/Neo cells but not in J/BCL-XL cells overexpressing BCL-XL. Additionally, several BCL-XL-sensitive intrinsic mitochondrial apoptotic events including apoptotic sub-G1 cell accumulation, TUNEL-positive DNA fragmentation, BAK activation, mitochondrial membrane potential (Δψm) loss, caspase-9/caspase-8/caspase-3 activation, and PARP cleavage were induced only in J/Neo cells. Both cytosolic and mitochondrial ROS levels were elevated in quercetin-treated J/Neo cells; however, the ROS elevations were almost completely abrogated in J/BCL-XL cells, suggesting the ROS elevations were downstream of BCL-XL-sensitive mitochondrial damage and dysfunction. Wild-type A3, FADD-deficient I2.1, and caspase-8-deficient I9.2 Jurkat clones exhibited similar susceptibilities to the cytotoxicity of quercetin, excluding an involvement of extrinsic pathway in triggering the apoptosis. The autophagic events such as attenuation of AKT-mTOR pathway, formation of acridine orange-stainable acidic vesicular organelles, conversion of microtubule-associated protein 1 light chain 3-I (LC3-I) to LC3-II, and downregulation of p62/SQSTM1 level were detected in quercetin-treated J/Neo and J/BCL-XL cells, regardless of BCL-XL overexpression. Cotreatment with the autophagy inhibitor (3-methyladenine, LY294002, or chloroquine) resulted in a significant enhancement of quercetin-induced BAK activation and subsequently the mitochondrial damage-mediated apoptosis pathway by augmenting the downregulation of BAG3 and MCL-1 levels in J/Neo cells. These results demonstrated that quercetin induces intrinsic apoptosis and cytoprotective autophagy, and autophagy inhibition can potentiate BAK-dependent apoptotic activity of quercetin in Jurkat T cells.

Treatment of human T-cell acute lymphoblastic leukemia cells with CFTR inhibitor CFTRinh-172

Our previous studies have demonstrated that a previously unrecognized role of CFTR in hematopoiesis and acute leukemia. Here, we show that CFTR inhibitor CFTR-inh172 possesses ability to inhibit human T-cell acute lymphoblastic leukemia cells. In detail, CFTR-inh172 inhibited cell proliferation, promoted apoptosis and arrested the cell cycle in human T-cell acute lymphoblastic leukemia cell CCRF-CEM, JURKAT and MOLT-4. Furthermore, transcriptome analysis reveals that CFTR-inh172 induces significant alteration of gene expression related to apoptosis and proliferation. These findings demonstrate the potential of CFTR inhibitor CFTR-inh172 in human T-cell acute lymphoblastic leukemia treatment.

TimosaponinA‑III induces autophagy of T‑cell acute lymphoblastic leukemia Jurkat cells via inhibition of the PI3K/Akt/mTOR pathway.

TimosaponinA‑III (TAIII) is a saponin isolated from anemarrhena asphodeloides and possesses the inhibitory effect on proliferation of multiple tumor cells. In the present study, the antitumor effect of TAIII and its underlying molecular mechanisms were investigated invitro in T‑cell acute lymphoblastic leukemia (T‑ALL) Jurkat cells. The results demonstrated that TAIII inhibits the viability of Jurkat cells in a time‑and dose‑dependent manner, and induces apoptosis of Jurkat cells in a dose‑dependent manner. Transmission electron microscopy demonstrated the formation of numerous autophagosomes in TAIII‑treated Jurkat cells. Furthermore, monodansylcadaverine (MDC)‑labeled autophagic vacuoles were observed following TAIII treatment by an inverted fluorescence microscope and MDC accumulation increased notably in TAIII treatment groups in a concentration‑dependent manner. B‑cell lymphoma‑2 (Bcl‑2)‑associatedX (Bax) was upregulated while Bcl‑2 was reduced following TAIII treatment, indicating that the pro‑apoptotic mechanism of TAIII may be associated with upregulation of Bax. Further investigation revealed that TAIII promotes the expression of autophagy‑associated proteins Beclin1 and LC3‑II, and inhibits the phosphoinositide3‑kinase/Akt/mechanistic target of rapamycin kinase pathway. The present study revealed that the antitumor activity of TAIII was primarily achieved by the induction of cell apoptosis and autophagy, indicating a promising potential as a novel effective reagent against T‑ALL.

3D culture enhances chemoresistance of ALL Jurkat cell line by increasing DDR1 expression

Three dimensional (3D) culture has gradually become a research hotspot in the field of drug screening, stem cell research, and tissue engineering due to its more physiological-like morphology and function. In this study, we compared the differences of cell proliferation, population, protein expression and chemoresistance profiles between two dimensional (2D) and 3D culture of acute lymphoblastic leukemia (ALL) Jurkat cell line. Polycaprolactone (PCL) is used for 3D culture owing to its biochemical properties and compatibility. Culturing of ALL Jurkat cell line in collagen type I coated polycaprolactone scaffold for 168 h increased cell proliferation, attachment, as well as the drug resistance to cytarabine (Ara-C) and daunorubicin (DNR) without changing the original CD2+CD3+CD4+dimCD8−CD34−CD45+dim phenotype, compared to uncoated PCL scaffold and tissue culture plate systems. Molecularly, increased chemoresistance is associated with the upregulation of discoidin domain receptor 1 (DDR1) and transcription factor STAT3. Inhibition of DDR1 activity by DDR1-specific inhibitor DDR-IN-1 accelerated cell death in the presence of Ara-C, DNR or their combination. These results demonstrated that 3D culture enhances chemoresistance of ALL Jurkat cell line by increasing DDR1 expression. Importantly, the cell adhesion-mediated drug resistance induced by DDR1 in the scaffold was similar to the clinical situation, indicating the 3D culture of cancer cells recapitulate the in vivo tumor environment and this platform can be used as a promising pre-clinic drug-screen system.

Role of epigenetic regulation on the induction of apoptosis in Jurkat leukemia cells by white grape pomace rich in phenolic compounds.

Grape pomace is a rich source of phenolic compounds commonly employed for elaboration of dietary supplements. The aim of the present study was to investigate the anticancer effect of a purified white grape pomace extract (PWGPE) in acute lymphoblastic leukemia Jurkat cells and to characterize the underlying mechanism. Apoptosis, mitochondrial membrane potential and reactive oxygen species (ROS) levels were assessed by flow cytometry and protein expression levels were analysed by Western blotting. PWGPE induced apoptosis in Jurkat cells in a time- and concentration-dependent manner. The anticancer effect was associated with an increased expression of p73 and down-regulation of pro-survival factors, including p-Akt, Bcl-2, and survivin. PWGPE reduced the expression of several proteins that block the expression of apoptosis-related genes such as DNMT1, HDAC1/2, UHRF1, and the polycomb group protein members: EZH2, SUZ12, and BMI1. In addition, the extract induced the formation of ROS, whereas pre-treatment with PEG-catalase and N-acetylcysteine prevented the ROS formation and markedly decreased the induction of apoptosis. These findings suggest that PWGPE-induced apoptosis in Jurkat human leukemia cells, is mediated by mitochondrial depolarization and caspase-3 cleavage, and depends on ROS generation and regulation of epigenetic gene silencing. Therefore, PWGPE may play an important role in the treatment of acute lymphoblastic leukemia (ALL).

The effect of miR-146a on STAT1 expression and apoptosis in acute lymphoblastic leukemia Jurkat cells.

The effect of miR-146a-dependent regulation of STAT1 on apoptosis in acute lymphoblastic leukemia (ALL) Jurkat cells was investigated. The miR-146a mimic and miR-146a inhibitor vectors were constructed in vitro, and experimental grouping was as follows: Control group (untreated Jurkat cells), empty vector group (Jurkat cells transfected with empty vector), agonist group (Jurkat cells transfected with miR-146a mimic) and the inhibitor group (Jurkat cells transfected with miR-146a inhibitor). Western blot analysis was used to observe the expression, respectively, of STAT1, p-STAT1 and Bcl-xL, and flow cytometry was used to test apoptosis in Jurkat cells. STAT1 and p-STAT1 expression in the agonist group was higher than that in the control and empty vector groups, but lower in the inhibitor group, and differences were statistically significant (P<0.05). The rate of apoptosis in the agonist group was significantly higher than that of the control group and blank vector group, and it was significantly lower in the inhibitor group (P<0.05). As a tumor suppressor, miR-146a can regulate expression of apoptosis-promoting factor STAT1, and anti-apoptosis factor Bcl-xL, and is able to promote apoptosis of ALL Jurkat cells.

LXR agonist regulates the proliferation and apoptosis of human T-Cell acute lymphoblastic leukemia cells via the SOCS3 pathway

BackgroundRecent studies show that Liver X receptors (LXR) activation is involved in the regulation of tumor cell death in solid cancer via E2 factor (E2F) transcription factor or suppressor of cytokine signaling-3 (SOCS3) pathway. However, the effect of LXR activation on leukemic cell fate has not been tested. MethodsTwo human acute lymphoblastic leukemia (ALL) cell lines, Jurkat and SupT1, were cultured. Cells were transfected with small-interfering RNA (si-RNA) against SOCS3 and E2F family members (including E2F1, E2F2 and E2F3a) followed by treatment with LXR activator GW3965. The cellular biological behaviors, including proliferation, colony-forming ability and apoptosis were tested afterward. ResultsActivation of LXR by GW3965 significantly decreased the cell proliferation rates and colony-forming abilities in the Jurkat and SupT1 cells, but increased their apoptosis rates. Western blot assay show that GW3965 treatment dramatically up-regulated the SOCS3 protein in both cell lines, without affecting E2F1, E2F2 and F2F3a expression levels. SOCS3 inhibition by si-RNA transfection, instead of E2F1, E2F2 and F2F3a pathway inhibition, abolished the aforementioned effects of LXR activation on Jurkat and SupT1 cells. ConclusionOur finding suggests that LXR activation regulates leukemic cell fate and biological behavior via SOCS3 pathway, rather than E2F family members.

Effects of valproic acid and pioglitazone on cell cycle progression and proliferation of T-cell acute lymphoblastic leukemia Jurkat cells.

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematologic malignant tumor. Administration of chemical compounds influencing apoptosis and T cell development has been discussed as promising novel therapeutic strategies. Valproic acid (VPA) as a recently emerged anti-neoplastic histone deacetylase (HDAC) inhibitor and pioglitazone (PGZ) as a high-affinity peroxisome proliferator-activated receptor-gamma (PPARγ) agonist have been shown to induce apoptosis and cell cycle arrest in different studies. Here, we aimed to investigate the underlying molecular mechanisms involved in anti-proliferative effects of these compounds on human Jurkat cells. Treated cells were evaluated for cell cycle progression and apoptosis using flowcytometry and MTT viability assay. Real-time RT-PCR was carried out to measure the alterations in key genes associated with cell death and cell cycle arrest. Our findings illustrated that both VPA and PGZ can inhibit Jurkat E6.1 cells in vitro after 24 hr; however, PGZ 400 μM presents the most anti-proliferative effect. Interestingly, treated cells have been arrested in G2/M with deregulated cell division cycle 25A (Cdc25A) phosphatase and cyclin-dependent kinase inhibitor 1B (CDKN1B or p27) expression. Expression of cyclin D1 gene was inhibited when DNA synthesis entry was declined. Cell cycle deregulation in PGZ and VPA-exposed cells generated an increase in the proportion of aneuploid cell population, which has not reported before. These findings define that anti-proliferative effects of PGZ and VPA on Jurkat cell line are mediated by cell cycle deregulation. Thus, we suggest PGZ and VPA may relieve potential therapeutic application against apoptosis-resistant malignancies.

Andrographolide inhibits growth of human T-cell acute lymphoblastic leukemia Jurkat cells by downregulation of PI3K/AKT and upregulation of p38 MAPK pathways.

T-cell acute lymphoblastic leukemia (T-ALL) as a prevalent hematologic malignancy is one of the most common malignant tumors worldwide in children. Andrographolide (Andro), the major active component from Andrographis paniculata, has been shown to possess antitumor activities in several types of cancer cells. However, whether Andro would inhibit T-ALL cell growth remains unclear. In this study, we investigated the cytotoxic effect of Andro on human T-ALL Jurkat cells and explored the mechanisms of cell death. Cell apoptosis was assayed by flow cytometry, and the signaling transduction for Andro was analyzed by Western blotting. The results indicated 10 μg/mL Andro could significantly induce Jurkat cells’ apoptosis, depending on the inhibition of PI3K/AKT pathway. Moreover, Andro-induced apoptosis is enhanced by AKT-selective inhibitor LY294002. ERK- or JNK-selective inhibitors PD98059 and SP600125 had no effect on Andro-induced apoptosis. In addition, p38 inhibitor SB203580 could reverse Andro-induced apoptosis in Jurkat cells. We also found that the protein expression of p-p53 and p-p38 were increased after Andro treatments. The result of an in vivo study also demonstrated Andro’s dose-dependent inhibition in subcutaneous Jurkat xenografts. In conclusion, our findings explained a novel mechanism of drug action by Andro in Jurkat cells and suggested that Andro might be developed into a new candidate therapy for T-ALL patients in the coming days.