Effects of vascular endothelial growth factors and their receptors on megakaryocytes and platelets and related diseases.

It is well known that vascular endothelial growth factors (VEGFs) and their receptors (vascular endothelial growth factor receptors, VEGFRs) are expressed in different tissues, and VEGF-VEGFR loops regulate a wide range of responses, including metabolic homeostasis, cell proliferation, migration and tubuleogenesis. As ligands, VEGFs act on three structurally related VEGFRs (VEGFR1, VEGFR2 and VEGFR3 [also termed FLT1, KDR and FLT4, respectively]) that deliver downstream signals. Haematopoietic stem cells (HSCs), megakaryocytic cell lines, cultured megakaryocytes (MKs), primary MKs and abnormal MKs express and secrete VEGFs. During the development from HSCs to MKs, VEGFR1, VEGFR2 and VEGFR3 are expressed at different developmental stages, respectively, and re-expressed, e.g., VEGFR2, and play different roles in commitment, differentiation, proliferation, survival and polyplodization of HSCs/MKs via autocrine, paracrine and/or even intracrine loops. Moreover, VEGFs and their receptors are abnormally expressed in MK-related diseases, including myeloproliferative neoplasms, myelodysplastic syndromes and acute megakaryocytic leukaemia (a rare subtype of acute myeloid leukaemia), and they lead to the disordered proliferation/differentiation of bone marrow cells and angiogenesis, indicating that they are closely related to these diseases. Thus, targeting VEGF-VEGFR loops may be of potential therapeutic value.

Phosphorylation of ribosomal protein S6 kinase 1 at Thr421/Ser424 and dephosphorylation at Thr389 regulates SP600125-induced polyploidization of megakaryocytic cell lines.

Megakaryocytes (MKs) are one of the few cell types that become polyploid; however, the mechanisms by which these cells are designated to become polyploid are not fully understood. In this investigation, we successfully established two relatively synchronous polyploid cell models by inducing Dami and CMK cells with SP600125. We found that SP600125 induced the polyploidization of Dami and CMK cells, concomitant with the phosphorylation of ribosomal protein S6 kinase 1 (S6K1) at Thr421/Ser424 and dephosphorylation at Thr389. The polyploidization was partially blocked by H-89, a cAMP-dependent protein kinase (PKA) inhibitor, through direct binding to S6K1, leading to dephosphorylation at Thr421/Ser424 and phosphorylation at Thr389, independent of PKA. Overexpression of a rapamycin-resistant mutant of S6K1 further enhanced the inhibitory effect of LY294002 on the SP600125-induced polyploidization of Dami and CMK cells. SP600125 also induced the polyploidization of Meg-01 cells, which are derived from a patient with chronic myelogenous leukemia, without causing a significant change in S6K1 phosphorylation. Additionally, SP600125 induced the polyploidization of HEL cells, which are derived from a patient with erythroleukemia, and phosphorylation at Thr389 of S6K1 was detected. However, the polyploidization of both Meg-01 cells and HEL cells as a result of SP600125 treatment was lower than that of SP600125-induced Dami and CMK cells, and it was not blocked by H-89 despite the increased phosphorylation of S6K1 at Thr389 in both cell lines in response to H-89. Given that the Dami and CMK cell lines were derived from patients with acute megakaryocytic leukemia (AMKL) and expressed high levels of platelet-specific antigens, our data suggested that SP600125-induced polyploidization is cell-type specific, that these cell lines were more differentiated, and that phosphorylation at Thr421/Ser424 and dephosphorylation at Thr389 of S6K1 may play an important role in the SP600125-induced polyploidization of these cell lines synergistically with other signaling pathways.

[Autologous cytokine-induced killer cells therapy on the quality of life of patients with breast cancer after adjuvant chemotherapy: a prospective study].

OBJECTIVE: To explore the effect of autologous cytokine-induced killer cells on the quality of life in patient with breast cancer who have already finished the adjuvant chemotherapy. METHODS: One hundred and twenty-eight postoperative patients with breast cancer who underwent anthracycline-based adjuvant chemotherapy were enrolled in this prospective study, and they were randomized into 2 groups, i.e., treatment group, which received the therapy of CIK cells transfusion, and control group, which was given regular follow-up. Meanwhile, patients with positive hormone receptor in the two groups were given endocrine therapy, and the patients with positive axillary lymph nodes were given radiotherapy to the chest wall and regional lymph nodes. The difference of quality of life between the two groups was analyzed according to the EORTC QLQ-BR53 quality of life questionnaire, and the adverse reactions were monitored. RESULTS: As regarding the functional evaluation, the physical function scores of patients of the treatment group were (83.43 ± 14.87) and (88.55 ± 11.62) at 3 and 6 months after the CIK cell therapy, respectively, significantly higher than the baseline value [(74.83 ± 13.82), P < 0.05)]. Global health status/QOL scores were (83.30 ± 19.09) and (89.68 ± 10.81), significantly higher than the baseline value [(77.72 ± 21.05), P < 0.05]. As regarding symptoms, the scores of fatigue, nausea, vomiting and loss of appetite of patients in the treatment group were higher than the baseline value, with significant differences (P < 0.05). The nausea and vomiting scores in the control group at 3 and 6 months of followed-up were (26.67 ± 22.56) and (21.47 ± 21.06), significantly lower than the baseline values [(33.31 ± 27.07), P < 0.05]. The scores of worrying about the future in the patients of treatment group were (47.56 ± 30.84) and (42.33 ± 26.95) after 3 and 6 months, significantly better than the baseline value [(57.41 ± 30.63), P < 0.05]. The systematic therapy side effects scores were (31.95 ± 27.52) and (23.72 ± 22.87), significantly better than the baseline value [(40.56 ± 26.28), P < 0.05]. The scores of arm edema were (45.26 ± 25.42) and (36.61 ± 20.51), significantly milder than the baseline value [(55.11 ± 22.82), P < 0.05]. In the control group, the scores of arm edema were (44.85 ± 28.94) and (38.64 ± 23.68), significantly lower than the baseline values [(53.26 ± 23.84) points, P < 0.05]. Alopecia scores were (29.93 ± 24.72) and (24.18 ± 22.66), significantly lower than the baseline values [(35.92 ± 22.08), P < 0.05]. In the treatment group, the patients' physical function, social function and global health status/QOL, fatigue, insomnia, and worrying about the future rates were significantly higher than that of the control group (P < 0.05 for all). Three patients after CIK reinfusion had transient fever, and 6 cases felt pain in the lower limb, but the symptoms were relieved after symptomatic treatment. CONCLUSIONS: Therapy of autologous CIK cells transfusion can significantly improve the quality of life of breast cancer patients, and the adverse reactions during the treatment can be alleviated by symptomatic treatment.

[mTOR/p70s6k signaling pathway is involved in megakaryocyte polyploidization].

AIM: To investigate the mechanisms of megakaryocyte polyploid cell cycle control. METHODS: The expression and phosphorylation of mTOR/p70s6k pathway proteins was detected by western blot. Double-labeling techniques were used to investigate in which of the phase of the polyploid cell cycle S6K1 at Thr421/Ser424 are phosphorylated. RESULTS: Nocodazole induced a relatively synchronized polyploidization in Dami cells. The expression of mTOR and the phosphorylation of mTOR at Ser2448 increased when Dami cells begin to progress from G1 to S-phase in cell cycle. Analysis of flow cytometry showed that phosphorylation of S6K1 at Thr421/Ser424 increased at G2/M-phase. CONCLUSION: mTOR/S6K1 pathway is involved in megakaryocyte polyploid cell cycle control.

Identification and characterization of the CD226 gene promoter.

CD226 is one of the main activating receptors on natural killer cells, and it can induce cytotoxicity to target cells through interaction with its ligands CD155 or CD112. CD226 is also involved in T cell differentiation, activation, and cytotoxicity. The expression of CD226 on natural killer cells and T cells can be regulated by cytokines and chemical stimuli; however, the mechanism of the regulation of the CD226 gene is still unknown. In this study, we have identified two promoters in the human CD226 gene named P1 and P2, which are located at -810 to -287 bp and +33 to +213 bp, respectively, and a negative regulation element between P1 and P2. Both P1 and P2 can be regulated by phorbol ester (12-O-tetradecanoylphorbol-13-acetate) and calcium ionophore (A23187). Bioinformatics analysis shows that, within this CD226 gene region, there are putative binding sites for transcription factors AP-1, Sp1, PEA3, and Ets-1. We have found that transcription factor activating protein-1 (AP-1) can up-regulate CD226 promoters P1 and P2 in human hepatocarcinoma cells, a hepatocarcinoma cell line with low expression of endogenous AP-1 and Ets-1. Interestingly, the transcription factor Ets-1 promotes AP-1-induced P2 activity but inhibits AP-1-induced P1 activity for which a 10-bp AP-1/Ets-1 composite site (CCTTCCTTCC) in P1 may be responsible.

[The proliferation, phenotype change and anti-tumor activity of cytokine induced killer cells].

AIM: To study the growth regularity, the phenotype change and the cytotoxicity of CIK cells. METHODS: The number of CIK cells was counted by living cell counting in different culturing time to observe the growth of the CIK cells, and the phenotype change of the CIK cells was detected by flow cytometry. Meanwhile cytotoxicity of CIK cells to tumor cell lines was also detected by CytoTox96 non-radiated cytotoxicity kit. RESULTS: After stimulated by cytokines and anti-CD3 antibody, CIK cells can proliferate significantly. The cell number of CIK was increased to 473.28+/-27.53 fold in serum-free medium plus auto-serum, 218.24+/-16.86 fold in serum-free medium and only 11.52+/-1.04 fold in RPMI1640 plus fetal FCS, respectively. The CD3(+)+CD8(+), CD3(+)+CD56(+), CD226(+)+CD11a(+) and CD305(+)+CD11a(+) cells were increased with the progression of the cultural time and the CD3(+)+CD4(+) cells were decreased with the progression of cultural time. The cytotoxicity of CIK cells to tumor cell lines was significantly higher than that of LAK cells (P<0.01) and its cytotoxicity was increased with progression of the cultural time. CONCLUSION: CIK cells have strong proliferative ability and higher cytotoxicity to tumor cells in vitro, which could be used as a potential anti-tumor adoptive immunotherapy in clinic.