Activation of JAK/STAT in ovarian high-grade serous cancers and its prognostic significance / 北京大学学报(医学版)

OBJECTIVE@#The activation of Janus kinase (JAK) and signal transducers and activators of transcription (STAT) plays an important role in the prognosis and targeted therapy of ovarian high-grade serous carcinoma (HGSC). Utilizing simple and practicable technique, this study aimed to evaluate the activation of JAK/STAT signaling pathway in ovarian HGSC patients, and investigated the correlation between the activation of JAK/STAT signaling pathway and the prognosis of the HGSC patients.@*METHODS@#We performed immunohistochemistry of phosphorylated STAT3 (pSTAT3) and phosphorylated STAT5 (pSTAT5) on paraffin imbedded slides of 73 ovarian HGSC patients, and evaluated the expression level and range of both markers. According to the grading score of the immunostaining of pSTAT3 and pSTAT5, we divided the 73 ovarian HGSC cases into STAT3 low/high expression and STAT5 low/high expression groups, and analyzed the prognosis of the patients in different groups, in order to explore the relationship between the expression of pSTAT3 and pSTAT5 proteins and the prognosis of the HGSC patients.@*RESULTS@#Some of the ovarian HGSC cases showed high expression of pSTAT3 and pSTAT5 protein level, which was related to the poorer prognosis of the HGSC patients. There was a significant difference in the expression level of pSTAT3 and pSTAT5 between the patients with better prognosis (survival time ≥3 years) and poorer prognosis (survival time < 3 years). The patients with higher protein expression of pSTAT3, pSTAT5 or both markers might have poorer prognosis, with significant shorter progression-free survival time and overall survival time (P < 0.001).@*CONCLUSION@#Immunostaining of pSTAT3 and pSTAT5 proteins might be helpful to evaluate and predict the prognosis of the ovarian HGSC patients, and to identify the patients who might have higher chances to respond to the STAT inhibitors and anti-angiogenesis therapy.

Effects of Paclitaxel and Quizartinib Alone and in Combination on AML Cell Line MV4-11 and Its STAT5 Signal Pathway / 中国实验血液学杂志

OBJECTIVE@#To investigate the effects of paclitaxel, quizartinib and their combination on proliferation, apoptosis and FLT3/STAT5 pathway of human leukemia cell line MV4-11 (FLT3-ITD+).@*METHODS@#MV4-11 cells were treated with paclitaxel and quizartinib at different concentrations for 24 h, 48 h and 72 h, respectively, and then the two drugs were combined at 48 h to compare the inhibition of proliferation, the apoptosis rate was detected by flow cytometry, the expression of FLT3 and STAT5 mRNA was determined by fluorescence quantitative PCR, and the protein expression of FLT3, p-FLT3, STAT5 and p-STAT5 was determined by Western blot.@*RESULTS@#Different combination groups of paclitaxel and quizartinib had synergistic inhibitory effect. The cell survival rate in the combination group was significantly lower than that in the single drug group (P<0.05). The cell apoptosis rate in the combination group was significantly higher than that in the single drug group (P<0.001). The expression of FLT3 mRNA in combination group was significantly higher than that in two single drugs (P<0.01). The expression of STAT5 mRNA in combination group was significantly higher than that in quizartinib group (P<0.001); increased compared with paclitaxel group, but there was no statistical significance. The expression level of p-FLT3、p-STAT5 protein in the combination group was significantly lower than that in the single drug group (P<0.05, P<0.05).@*CONCLUSION@#Paclitaxel combined with quizartinib can synergistically inhibit the proliferation of MV4-11 cell line and promote the apoptosis of MV4-11 cell line by inhibiting the activity of FLT3/STAT5 pathway.

Protective effects of Wuwei Xiaodu Drink against chronic osteomyelitis through Foxp3+CD25+CD4+ Treg cells via the IL-2/STAT5 signaling pathway / 中国天然药物

To explore the effectiveness and safety of a Chinese medicinal decoction Wuwei Xiaodu Drink (WWXDD) in inhibiting chronic osteomyelitis via regulatory T cells signaling. The effective constitutes of WWXDD and osteomyelitis related genes were screened. Target proteins were cross-validated using the Venny database. GO function and KEGG pathway analysis were performed for target proteins, while pharmacological network was constructed. The bone properties were analyzed by HE staining and the concentrations of immune factors were measured by ELISA. The expression of CTLA-4 and Foxp3 mRNA and STAT5, p-STAT5, CTLA-4 and Foxp3 protein were detected using Real-time PCR and Western blot, respectively. FACS was used to analyze the percentages of cells. A total of 117 genes overlapped between 785 target genes of the active compounds of WWXDD and 912 osteomyelitis related genes. Inflammation-related genes, including IL-6, TNFα, IL-1β and IL-2 showed high connection degree in the drug-compound-disease-target network. GO function and KEGG pathway analysis revealed that 117 intersection genes mainly enriched in virus infection related pathways, immune related pathways and chemokine signaling pathway. Furthermore, the development of chronic osteomyelitis was suppressed in model rats after treatment with WWXDD. Meanwhile, the concentrations of IL-2 and CD4+CD25+Foxp3 Treg percentages together with the levels of p-STAT5, CTLA-4 and Foxp3 were also down-regulated. Furthermore, IL-2 and WWXDD drug-containing serum exhibited opposite effects on regulating IL-2, IL-10, TGF-β1, Foxp3, CTLA4 and STAT5. In addition, a STAT5 phosphorylation inhibitor suppressed the expression of Foxp3 and CTLA-4. WWXDD can treat chronic osteomyelitis through suppressing the main regulating factors of Tregs and interfere its immunodepression. Our results bring a new solution for chronic osteomyelitis.

Synergistic role of JAK/STAT5 and PI3K/AKT signaling pathways in regulating eIF4B in acute leukemia / 生物工程学报

Human acute leukemia (AL) is a clonal malignancy with abnormal hematopoietic stem cells. Clinically, AL is very difficult to cure due to its sudden onset and short course of disease progression. Previous studies have shown that eukaryotic initiation factor 4B (eIF4B) plays a critical role in the development of chronic leukemia. However, the involvement of eIF4B in human acute leukemia is still largely unknown. Therefore, we studied eIF4B function and its regulatory mechanism in human acute leukemia. We found that phosphorylation levels of eIF4B in acute leukemia cells were significantly reduced in response to treatment with either LY294002 (PI3K inhibitor), AKTi (AKT inhibitor) or SMI-4A (Pim inhibitor). Co-treatment with inhibitors targeting JAK/STAT5/Pim and PI3K/AKT/mTOR signaling dramatically promoted apoptosis of acute leukemia cells by downregulating eIF4B phosphorylation. Furthermore, in vitro and in vivo functional experiments showed that eIF4B played an important anti-apoptosis role in the acute leukemia cells by regulating the expression of anti-apoptotic proteins Bcl-2 and Bcl-XL. In contrast, silencing eIF4B inhibited the growth of acute leukemia cells as engrafted tumors in nude mice. Taken together, our results indicate the synergistic role of JAK/STAT5/Pim and PI3K/AKT/mTOR signaling pathways in regulating eIF4B phosphorylation in acute leukemia, and highlight eIF4B as a candidate therapeutic target for treatment of acute leukemia.

Effect of Low-Dose Triptolide and Sorafenib Alone and Their Combination on AML Cell Line MV411 and the Pathway of STAT5 / 中国实验血液学杂志

OBJECTIVE@#To investigate the effects of inhibiting proliferation and inducing apoptosis of low-dose triptolide and sorafenib alone or in combination on FLT3-ITD acute myeloid leukemia cell line MV4-11 and STAT5 pathway.@*METHODS@#The MV4-11 cells were treated with low dose triptolide(IC) and sorafenib(IC) alone or in combination for 48 hours. The cell proliferation and inhibition were detected by using CCK-8 kit, the cell apoptosis was detected by flow cytometry, the expression of FLT3,STAT5 in mRNA and protein levels was detected by RT-PCR and Western blot respectively.@*RESULTS@#The treatment of MV4-11 cells with low dose triptolide and sorafenib alone and in combination for 48 hours could inhibit cell proliferation and induce cell apoptosis, moreover the inhibitory rate and apoptotic rate of MV4-11 cells in drug-combination group both were higher than those in single drug group. The mRNA expression and protein expression of FLT3,STAT5 signaling pathway in drug combination group were significantly lower than those in single drug group.@*CONCLUSION@#Low-dose triptolide combined with sorafenib can synergistically inhibit the proliferation and induce the apoptosis of MV4-11 cells, which may be related with the inhibition of FLT3 and STAT5 pathway.

Efecto de Estradiol y Testosterona sobre la activación de la vía JAK2/STAT5 inducida por hormona de crecimiento / Estradiol and Testosterone effect on the activation of the JAK2/STAT5 pathway induced by growth hormone

Abstract: Sex hormones play a major role during pubertal growth. Estradiol (E2) and testosterone (T) levels progressively increase during puberty and in the presence of growth hormone (GH), growth velocity increases. Understanding the interactions between sex hormones and GH, may optimize the treatment of pubertal children with growth disorders. The aim of our study was to investigate possible molecular mechanisms which might potentiate longitudinal growth during puberty due to E 2or T combined with GH. We evaluated the GH/JAK2/STAT5 signaling pathway in the human hepatoma cell line HEPG2. Our results suggest that sex hormones potentiate the GH signaling pathway in a dose dependent fashion. Relatively low concentrations of E 2associated with GH induce a substantial activation of the GH pathway, whereas relatively high concentrations of T associated with GH produce a similar effect. These findings are concordant with the physiology of the pubertal growth spurt, which is an early event in girls (when E 2 circulating levels are low), and a late event in boys (when T circulating levels are high).

Resumen: Las hormonas sexuales, modulan el crecimiento durante la pubertad. Los niveles de estradiol (E2) y testosterona (T) aumentan progresivamente durante la pubertad y en combinación con la hormona de crecimiento (GH), producen un incremento en la velocidad de crecimiento en este período conocido como el "estirón puberal". El estudio de la interacción entre las hormonas sexuales y la GH, es de gran importancia para optimizar el tratamiento de niños(as) con alteraciones del crecimiento durante la pubertad. El objetivo de nuestro estudio fue investigar los posibles mecanismos que podrían potenciar el crecimiento longitudinal durante la pubertad, en especial las interacciones entre E 2o T en combinación con GH. Se evaluó la activación de la vía de señalización GH/JAK2/STAT5 frente al estímulo combinado con estas hormonas en cultivos celulares de hepatoma humana HEPG2. Nuestros resultados sugieren que existe un efecto potenciador de las hormonas sexuales sobre la vía de señalización de GH. Observamos que concentraciones relativamente bajas de E2 junto con GH producen una clara activación de la vía de señalización para GH, mientras que concentraciones relativamente altas de T junto con GH producen una activación similar. Estos hallazgos son concordantes con la fisiología del estirón puberal, que es más precoz en niñas (cuando los niveles circulantes de E2 son bajos), y más tardíos en varones (cuando los niveles circulantes de T son altos).

Effects of Abnormal Iron Metabolism on EPO-STAT5 Signaling Pathway in Anemia Patients / 中国实验血液学杂志

OBJECTIVE@#To study the effects of iron metabolism abnormality on EPO-STAT5 signaling pathway in anemia patients.@*METHODS@#According to diseases, the patients were divided into 3 groups: lower risk myelodysplastic syndrome (MDS) group (30 cases) including 14 cases of non-iron over load and 16 cases of iron over load, 12 cases of them were treated by iron chelation therapy; anemia of chronic disease (ACD) group (12 cases) and iron deficiency anemia (IDA) group (12 cases). In addition, the healthy control group was selected. The iron metaloslism index (SF, SI, TIBC), serum level of EPO, plasma level of P-STAT5 and STAT-5 mRNA expression in peripheral blood cells were detected and compared in different groups. Moreover, the effects of iron metabolism abnormality on the expression of EPO and STAT5 in anemia patients were analyzed.@*RESULTS@#compared with non-iron over load group, the EPO level in iron over load group significantly increased (P<0.05), the expression of STAT5 mRNA and P-STAT5 significantly decreased (P<0.05). After iron chelation therapy, the EPO level in serum significantly decreased (P<0.05), the expression of STAT5 mRNA and P-STAT5 was up-regulated significantly (P<0.05). Compared with healthy control group, the expression of EPO in ACD group was down-regulated significantly, while the expression of STAT5 mRNA was not different, but the P-STAT5 expression was down-regulated significantly (P<0.05). Compared with the healtly control group, the EPO expression in IDA group was enhanced significantly (P<0.05), the expression of STAT5 mRNA and P-STAT5 were also significantly enhanced (P<0.05).@*CONCLUSION@#The excessive iron load or chronic inflammation may inhibit the activation of EPO-STAT5 signaling pathway and aggravate the anemia.

Effects of Sinopodophyllum hexundrum on apoptosis in K562 cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effects of Sinopodophyllum hexundrum on apoptosis in K562 cells.</p><p><b>METHODS</b>K562 cells were treated with Sinopodophyllum hexundrum at different concentrations and for different lengths of time to determine the optimal conditions of SinoPodophyllum hexandrum treatment for K562 cells using CCK8 assay. The cell apoptotic rate was detected by flow cytometry, and the cell morphology and nuclear morphology of K562 cells were observed with Wright staining and DPAI staining, respectively. The protein expressions of BCR/ABL, p-BCR/ABL, STAT5, p-STAT5 and the apoptosis-related proteins PARP, caspase-3 and cleaved-caspase-3 were determined with Western blotting.</p><p><b>RESULTS</b>The cell proliferation was inhibited in a concentration-and time-dependent manner by 1, 2, and 3 µg/mL Sinopodophyllum hexundrum. The treatment was optimal with a Sinopodophyllum hexundrum concentration of 2 µg/mL a treatment time of 48 h, and the cell apoptotic rate increased in a time-dependent manner and significantly increased at 48 h (P<0.001). The expression of apoptosis-related proteins PARP, caspase-3 and cleaved-caspase-3 were also activated in a time-dependent manner. The cells showed typical apoptotic changes after treatment with 2 µg/mL Sinopodophyllum hexundrum for 48 h with significantly reduced expressions of BCR/ABL, p-BCR/ABL, STAT5, AND p-STAT5.</p><p><b>CONCLUSION</b>Sinopodophyllum hexundrum promotes K562 cell apoptosis possibly by inhibiting BCR/ABL-STAT5 survival signal pathways and activating the mitochondrion-associated apoptotic pathways.</p>

The role of interleukin-2 pathway in pathogenesis of nasal polyps / 临床耳鼻咽喉头颈外科杂志

OBJECTIVE@#To study the expression of Interleukin2 (IL-2) signaling pathway related factors and Treg cell in nasal tissue of nasal polyps, so that to investigate the possible mechanism of IL-2 signaling pathway in the progress of nasal polyps and the correlation between IL-2 pathway and Treg cell.@*METHOD@#Thirty patients were enrolled for study, including the patients with nasal polyps and those with only deviated nasal septum as normal control. The nasal polyps tissue and the turbinate mucosa of the patients were collected during surgery. The expression levels of IL-2 and IL-2R were measured by means of ELISA. The level of pSTAT5 was evaluated by Western blot. We measured the level of Foxp3 mRNA in the tissue by real-time PCR, and the proportion of Treg cells was evaluated by flow cytometry. Finally. we analyzed the correlation between IL-2 pathway related factors and Treg cells in nasal polyps.@*RESULT@#The expression levels of IL-2. IL-2R and pSTAT5 were significantly decreased in the nasal polyps compared with normal control (P < 0.05), and the level of Foxp3 mRNA and proportion of Treg cells in patients with nasal polyps were significantly lower than in normal control (P < 0.05). Moreover, there was positive correlation between the levels of IL-2 pathway related factors and the levels of Foxp3 mRNA and Treg cells proportion in nasal polyps.@*CONCLUSION@#The activated state of IL-2 signaling pathway got changed in nasal polyps tissue, the level of which was positively correlated with the expression of Treg cells, indicating that the IL-2 signaling pathway may play a crucial role in the development of nasal polyps, and the decreased level of Treg cells in nasal polyps may result from the downregulation of IL-2 signaling pathway.

Degradation of the Transcription Factors NF-kappaB, STAT3, and STAT5 Is Involved in Entamoeba histolytica-Induced Cell Death in Caco-2 Colonic Epithelial Cells

Entamoeba histolytica is a tissue-invasive protozoan parasite causing dysentery in humans. During infection of colonic tissues, amoebic trophozoites are able to kill host cells via apoptosis or necrosis, both of which trigger IL-8-mediated acute inflammatory responses. However, the signaling pathways involved in host cell death induced by E. histolytica have not yet been fully defined. In this study, we examined whether calpain plays a role in the cleavage of pro-survival transcription factors during cell death of colonic epithelial cells, induced by live E. histolytica trophozoites. Incubation with amoebic trophozoites induced activation of m-calpain in a time- and dose-dependent manner. Moreover, incubation with amoebae resulted in marked degradation of STAT proteins (STAT3 and STAT5) and NF-kappaB (p65) in Caco-2 cells. However, IkappaB, an inhibitor of NF-kappaB, was not cleaved in Caco-2 cells following adherence of E. histolytica. Entamoeba-induced cleavage of STAT proteins and NF-kappaB was partially inhibited by pretreatment of cells with a cell-permeable calpain inhibitor, calpeptin. In contrast, E. histolytica did not induce cleavage of caspase-3 in Caco-2 cells. Furthermore, pretreatment of Caco-2 cells with a calpain inhibitor, calpeptin (but not the pan-caspase inhibitor, z-VAD-fmk) or m-calpain siRNA partially reduced Entamoeba-induced DNA fragmentation in Caco-2 cells. These results suggest that calpain plays an important role in E. histolytica-induced degradation of NF-kappaB and STATs in colonic epithelial cells, which ultimately accelerates cell death.

Analysis of clinical manifestations and genetic mutations in a child with Laron syndrome / 中华儿科杂志

<p><b>OBJECTIVE</b>To analyze clinical manifestations and gene mutations in a child with severe short stature, explore its molecular mechanism and further clarify the diagnostic procedure for short stature.</p><p><b>METHOD</b>We observed clinical characteristics of a patient with short stature and did diagnostic examinations, assessed the function of GH-IGF-1 axis, and surveyed its family members.Genomic DNA was extracted from peripheral blood, GHR, IGFALS, STAT5b and GH1 gene were amplified by PCR for sequencing, including exons and splicing areas.</p><p><b>RESULT</b>The patient presented symmetrical short stature (height -8.2 SDS) and facial features, and other congenital abnormalities.It displayed non-growth hormone deficiency. The baseline value of GH was 21 µg/L, and the peak was 57.9 µg/L. The value of IGF-1 was less than 25 µg/L, and the IGFBP-3 less than 50 µg/L. And IGF-1 generation test showed no response. There was no similar patients in the family members.Sequencing of GHR in the patient revealed a homozygous point mutation (c.Ivs6+1G>A), and her father and mother had the same heterozygous mutation. The same mutation was not identified for her sister.No other candidate gene was found.</p><p><b>CONCLUSION</b>As the result of combined clinical characteristics and lab examinations, as well as gene detection, the case was diagnosed with Laron syndrome and GHR gene mutation is the molecular mechanism.We should explicit the etiological diagnosis for short stature, and avoid missed diagnosis and misdiagnosis.</p>

STAT5 phosphorylation in CD34(+)CD38(-)CD123(+) bone marrow cells of the patients with myelodysplastic syndrome / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the expressions of STAT5 phosphorylation in CD34(+)CD38(-)CD123(+) bone marrow cells of the patients with myelodysplastic syndromes (MDS), and then evaluate the level of activation of STAT5 associated with cell proliferation in MDS clone cells.</p><p><b>METHODS</b>The bone marrow mononuclear cells (BMMNC) were extracted from 36 MDS patients and 14 normal controls. The mean fluorescence intensities (MFI) of phosphorylated STAT5(P-STAT5) in CD34(+)CD38(-)CD123(+) and CD34(+)CD38(-)CD123(-)cells, with or without the stimulation of 10 U/ml EPO, were examined by flow cytometry (FCM).</p><p><b>RESULTS</b>Without stimulation, the P-STAT5 MFI in CD34(+)CD38(-)CD123(+) cells of low/high risk MDS patients was 113.71 ± 67.22/173.05 ± 102.78, which was significantly higher than that of CD34(+)CD38(-)CD123(-) cells (58.84 ± 27.51/68.99 ± 50.42, P < 0.01, P < 0.05) and the normal controls CD34(+)CD38(-)CD123(-) cells (63.06 ± 21.06, P < 0.05), there was no significant difference between the CD34(+)CD38(-)CD123(-) cells of MDS patients and the normal control CD34(+)CD38(-)CD123(-) cells; With the EPO stimulation, the P-STAT5 MFI in CD34(+)CD38(-)CD123(+) cells of low/high risk MDS patients was 144.04 ± 58.11/239.45 ± 152.05, which was significantly higher than that of CD34(+)CD38(-)CD123(-) cells (68.41 ± 25, 10/64.21 ± 23.43, P < 0.01) and the normal controls CD34(+)CD38(-)CD123(-) cells (75.21 ± 27.02, P < 0.01), there was no significant difference between the CD34(+)CD38(-)CD123(-) cells of MDS patients and the normal control CD34(+)CD38(-)CD123(-) cells; The P-STAT5 MFI in the CD34(+)CD38(-)CD123(+) cells of low/high risk MDS patients with or without EPO stimulation were 21.80/28.86, which was significantly higher than that of CD34(+)CD38(-)CD123(-) cells (7.42/5.50, P < 0.01, P < 0.05) and the normal controls CD34(+)CD38(-)CD123(-) cells (6.39, P < 0.05), there was no significant difference between the CD34(+)CD38(-)CD123(-) cells of MDS patients and the normal controls CD34(+)CD38(-)CD123(-) cells; There was no significant difference of P-STAT5 MFI with or without EPO stimulation and the increased P-STAT5 MFI between the CD34(+)CD38(-)CD123(+) cells of low and high risk MDS.</p><p><b>CONCLUSION</b>STAT5 associated with cell proliferation was activated in CD34(+)CD38(-)CD123(+) bone marrow cells in MDS, which had more significant reactions to EPO than CD34(+)CD38(-)CD123(-) cells, indicating that CD34(+)CD38(-)CD123(+) bone marrow cells might be the real malignant MDS clone cells in MDS.</p>

JAK2V617F mutation and p-STAT5 protein expression in peripheral blood cells of patients with myeloproliferative neoplasm and their relations with clinical features / 中国实验血液学杂志

This study was aimed to explore the JAK2V617F mutation and p-STAT5 expression in patients with myeloproliferative neoplasm (MPN), and investigate their relations with clinical characteristics so as to provide theoretical basis for clinical practice and target therapy. Forty-five confirmed BCR-ABL-negative MPN patients and 15 healthy adults were enrolled in this study. Real-time fluorescent quantitative PCR and Western blot were respectively used to detect JAK2V617F mutation proportion and p-STAT5 expression level. In addition, their relations with clinical characteristics of MPN were analyzed. The results showed that the positive rate of JAK2V617F mutation in MPN patients was 73.3% (33/45), including 83.3% in polycythemia vera (PV) patients (20/24), 68.8% in essential thrombocythemia (ET) patients (11/16) and 40.0% in idiopathic myelofibrosis (IMF) patients (2/5). Mutation proportions of JAK2V617F in PV, ET and IMF patients were 0.472 ± 0.245, 0.216 ± 0.162, 0.435 ± 0.239 respectively; gray values of p-STAT5 protein in PV, ET and IMF patients were 1.396 ± 0.758, 0.760 ± 0.623, 0.792 ± 0.612 respectively. JAK2V617F mutation proportion and p-STAT5 protein expression level showed a linear correlation (P < 0.05). PV patients with higher JAK2V617F mutation proportion had higher white blood cell count, hemoglobin level and hematocrit, but lower platelet count; ET patients with higher mutation proportion showed older and higher white blood cell count, hemoglobin level and hematocrit, there was no significant difference between platelet count; IMF patients with higher JAK2V617F mutation proportion showed lower white blood cell count, platelet count, hemoglobin level and hematocrit. Patients with JAK2V617F positive mutation were more likely complicated by splenomegaly, bleeding and thrombotic events. It is concluded that the incidence rate of JAK2V617F mutation is high in patients with MPN. Higher mutation proportion always connected with higher expression of p-STAT5, and easily complicates by splenomegaly and thrombotic events.

Roles of STAT5 in hematopoietic regulation and blood diseases / 中国实验血液学杂志

Signal transducer and activator of transcription 5 (STAT5) is an important transcription factor existing in the cytoplasm of various types of cells. Once activated, STAT5 dimers translocate into nucleus and bind to the corresponding DNA sequence to regulate the transcription of its target genes. There are two isoforms of STAT5: STAT5A and STAT5B with 96% sequence homology and are encoded by two closely related but different genes. Studies have shown that STAT5 can regulate the survival, proliferation, differentiation and death of hematopoietic cells. Furthermore, elevated activation of STAT5 was found in many malignant hematologic diseases and therefore raised the possibility that STAT5 may be used as a new therapeutic target for blood related diseases. This review discusses the regulatory role of STAT5 in hematopoietic cells and its effect on the occurrence and development of blood diseases.

Synergistic effect of histone deacetylase inhibitor suberoylanilide hydroxamic acid with imatinib on K562 cells / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate synergistically killing effect of histone deacetylase (HDAC) inhibitor suberoylanilide hydroxamic acid (SAHA) combined with imatinib on human chronic myeloid leukemia (CML) cell line.</p><p><b>METHODS</b>K562 cells were co-treated with SAHA and imatinib. Cell growth was measured by MTT assay. Apoptosis was determined using Hoechst staining apoptosis detection kit and flow cytometric analysis. Activation of Caspase pathway, expression of Bcr-Abl and its downstream target genes, and expression of anti-apoptotic proteins were detected by Western blot.</p><p><b>RESULTS</b>SAHA synergized the cytotoxicity of imatinib against leukemia K562 cells, concomitantly with increased apoptosis and enhanced activation of Caspase-3, -8 and PRAP. The combination therapy resulted in significantly lower levels of Bcr-Abl,phosphorylated Bcr-Abl compared to treatment with either SAHA or imatinib alone. Furthermore,the co-treatment resulted in down-regulation of anti-apoptotic protein Mcl-1 expression. Also,marked down-regulated expression of JAK2,STAT5,and phosphorylated STAT5 was detected in the combination therapy.</p><p><b>CONCLUSION</b>Combining HDAC inhibitor SAHA with imatinib can kill CML cells synergistically by inhibiting cell growth and inducing apoptosis, which is associated with activation of Caspase pathway and regulation of anti-apoptotic proteins.</p>

Effects of hermap gene on p-STAT5 kinases in signal transduction pathway during erythroid differentiation / 中华血液学杂志

<p><b>OBJECTIVE</b>To study the effects of hermap gene on kinases in erythroid signal transduction pathway and investigate the mechanism of hermap on erythroid differentiation.</p><p><b>METHODS</b>The K562 cells expressing hermap and hermap-siRNA respectively were established for up- and down-regulating the expression of hermap gene. These K562 cells were then induced by Ara-C to erythroid differentiation and analyzed at 0, 24, 48, 72 and 96 h, respectively, for cell morphology and biphenylamine staining positive cells, determination of CD235a, CD36, kinases p-STAT5, p-Akt, p-MAPK and p-c-JUN by FCM; and quantification of hermap gene and γ (Aγ,Gγ) globin gene by FQ-PCR.</p><p><b>RESULTS</b>With up-regulating hermap gene and inducing by Ara-C, K562 cells were changing to low ratio of nucleus to cytoplasm, cytoplasm colour from basophilic to pinkish or amethyst tinge, increase of number of biphenylamine positive cells and expression of CD235a, CD36, γ (Aγ,Gγ) globin gene, hermap gene and p-STAT5 from 0 to 96 h. At 0, 24, 48, 72 and 96 h of culture, the positive rates of p-STAT5 cells were detected of 0.46%, 4.54%, 20.01%, 23.65% and 33.08%, respectively. This results demonstrated that there was a positive correlation between expression of p-STAT5 and hermap gene expression (P < 0.05).</p><p><b>CONCLUSION</b>hermap gene can stimulate erythroid differentiation of Ara-C induced K562 cells mainly through JAK/STAT5 signal transduction pathway.</p>

Effect of homoharringtonine combined with AG490 on JAK2-STAT5 associated signal pathway in HEL cells / 中国实验血液学杂志

This study was aimed to explore the effect of homoharringtonine in combination with AG490 on JAK2-STAT5 associated signal pathway in HEL cells, and analyze its mechanism so as to provide theoretical basis for therapy of chronic myeloproliferative neoplasma by new program. The cell survival rates were tested by MTT, apoptosis was tested by flow cytometry after HEL cells were treated by 20 ng/ml HHT, 100 µmol/L AG490 and 20 ng/ml HHT in combination with 100 µmol/L AG490, while the signal proteins such as P-JAK2, P-STAT5 and BCL-xL activated by abnormal activated JAK2 were tested by Western blot. The results showed that both HHT and AG490 could inhabit the HEL cell proliferation after being treated for 24 hours, and Annexin V-PI double staining confirmed early apoptosis while HHT effect was more obvious, Western blot showed that the expressions of P-JAK2 and P-STAT5 were down-regulated, while the total protein levels of JAK2 and STAT5 were stable. It is concluded that HHT combined with AG490 can obviously inhibit the proliferation and induce early apoptosis of HEL cells, and there is synergistic effect between the two drugs. HHT possibly acts as a broad-spectrum PTK inhibitor and synergistically with AG490 inhibits the phosphorylation of signal proteins caused by JAK2V617F, thus down-regulating the transcription of STAT5.

Leukemic stromal hematopoietic microenvironment negatively regulates the normal hematopoiesis in mouse model of leukemia / 癌症

<p><b>BACKGROUND AND OBJECTIVE</b>Leukemic microenvironment has a major role in the progression of leukemia. Leukemic cells can induce reversible changes in microenvironmental components, especially the stromal function which results in improved growth conditions for maintaining the malignant leukemic cells. This study aimed to investigate the survival advantage of leukemic cells over normal hematopoietic cells in stromal microenvironment in long term.</p><p><b>METHODS</b>The mice were injected intraperitoneally with N-N' ethylnitrosourea (ENU) to induce leukemia; the mice received injection of normal saline were used as control. At 180 days after ENU induction, the mice were killed and the bone marrows were cultured for 19 days. Colony-forming assays were used to analyze the formation of various cell colonies. The expression of Sca-1, CD146, VEGFR2, CD95, pStat3, pStat5, and Bcl-xL in marrow cells were detected by flow cytometry.</p><p><b>RESULTS</b>Long-term leukemic bone marrow culture showed abnormal elongated stromal fibroblasts with almost absence of normal hematopoietic cells. Adherent cell colonies were increased, but CFU-F and other hematopoietic cell colonies were significantly decreased in leukemia group (P<0.001). Primitive progenitor-specific Sca-1 receptor expression was decreased with subsequent increased expression of CD146 and VEGFR-2 in leukemic bone marrow cells. Decreased Fas antigen expression with increased intracellular pStat3, pStat5 and Bcl-xL proteins were observed in leukemic bone marrow cells.</p><p><b>CONCLUSIONS</b>Stromal microenvironment shows altered morphology and decreased maturation in leukemia. Effective progenitor cells are decreased in leukemia with increased leukemia-specific cell population. Leukemic microenvironment plays a role in promoting and maintaining the leukemic cell proliferation and survivability in long term.</p>

Effect of angelica polysaccharides co-erythropoietin on JAK2/STAT5 signal transduction pathway in hematopoietic stem/progenitor cells / 中国中药杂志

<p><b>OBJECTIVE</b>To investgate the signal transduction and regulation in erythropoiesis by angelica polysaccharides (APS) to clarify the mechanism for APS promoting hematopoiesis.</p><p><b>METHOD</b>The mononuclear cells were isolated from foetus umbilic cord blood (mononuclear cells, MNCs), after MNCs were incubated in the presence of APS group (APS 200 mg x L(-1)) and control group for 24 h, the cells were stimulated with Epo (5 U x mL(-1)) for 0, 2, 5, 30 min, respectively. STAT5 was measured by ICC and laser confocal scanning microscope. JAK2, STAT5 in nucleus and cytoplasm were measured by western-blotting-ECL.</p><p><b>RESULT</b>Angelica polysaccharide cooperated with Epo has significant impact on the expression of STAT5. The expression of STAT5 has significant difference between APS group and the control group at 4 time points. JAK2, STAT5 expressed in cytoplasm and nuclear of APS group significantly increased as compared to those of control group, and they expressed the strongest at 5 min.</p><p><b>CONCLUSION</b>JAK2, STAT5 signal transduction molecule plays an important role in the effect of APS cooperated with Epo on promoting hematopoiesis.</p>

Knockout of the tumor necrosis factor a receptor 1 gene can up-regulate erythropoietin receptor during myocardial ischemia-reperfusion injury in mice / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Tumor necrosis factor a receptor 1 (TNFalphaR1) plays an important role in the signal pathway of apoptosis. The objective of this study was to investigate the effects of TNFalphaR1 knockout on the up-regulation of erythropoietin receptor (Epo-R) and the coordinated anti-apoptosis functions during myocardial ischemia-reperfusion injury in mice.</p><p><b>METHODS</b>The ischemia-reperfusion injury model for cardiomyocytes was performed by ligating the left circumflex branch artery of TNFalphaR1 knockout (P55(-/-)) C17 B6 mice, as well as wild-type (P55(+/+)) C17 B6 mice. Triphenyltetrazolium chloride (TTC) staining was performed to observe the damaged area of the heart. TUNEL staining and DNA fragmentation were used to identify apoptosis. Mitochondrial Bcl-2 and Bax as well as expression of Epo-R and its downstream genes (Jak-2, stat-5, Akt, IkB-alpha, HIF-1alpha) were measured by Western blotting. The gene knockout mice were assigned into those undergoing the apoptosis surgical model group (KO group), and those subjected to sham operation (KOs group). Similarly, wild-type mice were either exposed to the surgical model (WT group) or subject to a sham operation (WTs group).</p><p><b>RESULTS</b>The myocardial damage ratio of the wild-type group after the operation was significantly higher than that of the knockout group, (50.5 +/- 6.4)% vs (36.9 +/- 6.9)%, P < 0.01. Similarly, TUNEL positive ratio of the wild-type group was significantly higher than that of the knockout group, (63.1 +/- 5.6)% vs (42.1 +/- 4.7)%, P < 0.01. The gray value ratios of Epo-R, Jak-2, stat-5, Akt, IkB-alpha, HIF-1 and mitochondrial Bcl-2 in the KO group were significantly higher than those of the WT group, P < 0.05; however, mitochondrial Bax was significantly lower than that of the WT group significantly (P < 0.05).</p><p><b>CONCLUSIONS</b>Using the ischemia-reperfusion injury model in mice, cardiomyocytes of TNFalphaR1 knockouts exhibited anti-apoptotic characteristics. This information could be used to coordinate the prevention of myocardial apoptosis by up-regulating and activating the Epo-R pathway.</p>