Saucernetin-7 isolated from Saururus chinensis inhibits proliferation of human promyelocytic HL-60 leukemia cells via G0/G1 phase arrest and induction of differentiation

In the present study, we investigated the in vitro effect ofsaucernetin-7, which is a dineolignan isolated from Saururuschinensis, on the proliferation, cell cycle-regulation and differentiationof HL-60 human promyelocytic leukemia cells. Saucernetin-7 potentlyinhibited the proliferation of HL-60 cells in both a dose- andtime-dependent manner with an IC₅₀,     

G2/M cell cycle arrest and apoptosis induced by COH-203 in human promyelocytic leukemia HL-60 cells

The combretastatin A-4/oltipraz hybrid (COH), 5-(3-amino-4-methoxyphenyl)-4-(3,4,5-trimethoxyphenyl)-3H−1,2-dithiole-3-one (COH-203) is one of the COH compounds synthesized by our previous study, which has been reported to affect a number of cancer cell lines, such as SGC-7901, KB, HT-1080, HepG2, SMMC-7721 and BEL-7402. The sensitivity of human acute leukemia cell lines to COH-203, and the mechanism underlying its anti-proliferative effects remain unknown, which was investigated in the present study. In the present study, it was demonstrated that COH-203 had notable time- and dose-dependent antiproliferative effects on the human acute promyelocytic leukemia HL-60 cell line. Furthermore, COH-203 treatment resulted in cell cycle arrest at G₂/M phase in a dose-dependent manner, and subsequently induced apoptosis. Western blot analysis revealed that upregulation of cyclin B was associated with G₂/M arrest. In addition, treatment with COH-203 resulted in downregulated expression of Bcl-2. This result revealed that COH-203-induced apoptosis in HL-60 cells may occur via the mitochondrial pathway in a caspase-dependent manner.     

Knockdown of MED19 by lentivirus-mediated shRNA in human osteosarcoma cells inhibits cell proliferation by inducing cell cycle arrest in the G0/G1 phase

MED 19 is a subunit of the mediator complex, which is a coactivator of RNA polymerase II and also interacts with the downstream coding region of many genes. However, the role of MED19 in osteosarcoma is unknown. In the present study, we applied lentivirus-mediated short hairpin RNA (shRNA)-triggered RNA interference to downregulate MED19 expression in human osteosarcoma SaOS-2 and U2OS cells. Knockdown of MED19 expression was confirmed by real-time PCR and Western blot. It was found that silencing of MED19 resulted in decreased cell viability, colony formation capacity, and DNA synthesis ability in both cells, as well as the G0/G1 phase cell cycle arrest. These results implied that MED19 played an important role in cell growth and cell cycle progression of human osteosarcoma cells. MED19 may be an attractive candidate for the therapeutic target in osteosarcoma.     

Suppression of STIM1 inhibits human glioblastoma cell proliferation and induces G0/G1 phase arrest

Background

Depletion of calcium (Ca²⁺) from the endoplasmic reticulum (ER) activates the ubiquitous store-operated Ca²⁺ entry (SOCE) pathway which sustains long-term Ca²⁺ signals and is critical for cellular functions. Stromal interacting molecule 1 (STIM1) serves a dual role as an ER Ca²⁺ sensor and activator of SOCE. Aberrant expression of STIM1 could be observed in several human cancer cells. However, the role of STIM1 in regulating tumorigenesis of human glioblastoma still remains unclear.

Methods

Expression of STIM1 protein in a panel of human glioblastoma cell lines (U251, U87 and U373) in different transformation level were evaluated by Western blot method. STIM1 loss of function was performed on U251 cells, derived from grade IV astrocytomas-glioblastoma multiforme with a lentvirus-mediated short harpin RNA (shRNA) method. The biological impacts after knock down of STIM1 on glioblastoma cells were investigated in vitro and in vivo.

Results

We discovered that STIM1 protein was expressed in U251, U87 and U373 cells, and especially higher in U251 cells. RNA interference efficiently downregulated the expression of STIM1 in U251 cells at both mRNA and protein levels. Specific downregulation of STIM1 inhibited U251 cell proliferation by inducing cell cycle arrest in G0/G1 phase through regulation of cell cycle-related genes, such as p21^Waf1/Cip1_, cyclin D1 and cyclin-dependent kinase 4 (CDK4), and the antiproliferative effect of STIM1 silencing was also observed in U251 glioma xenograft tumor model.

Conclusion

Our findings confirm STIM1 as a rational therapeutic target in human glioblastoma, and also indicate that lentivirus-mediated STIM1 silencing is a promising therapeutic strategy for human glioblastoma.     

贝母素乙通过诱导G0/G1期阻滞抑制结肠癌细胞的增殖

目的：探讨贝母素乙对结肠癌HCT116细胞增殖的抑制作用及其分子机制。方法：利用不同浓度的贝母素乙处理人结肠癌细胞HCT116和正常结肠上皮细胞CCD841 CON,通过CCK-8法和结晶紫染色法检测贝母素乙对HCT116和CCD841CON细胞增殖活力的影响,流式细胞术和WB法检测贝母素乙对HCT116细胞周期及其细胞周期相关蛋白表达的影响。构建HCT116移植瘤裸鼠模型和AOM/DSS结肠癌小鼠模型,观察贝母素乙对小鼠模型肿瘤生长和OS的影响,免疫组化法和WB法检测对移植瘤或肿瘤组织中细胞周期相关蛋白CDK4、CDK6和cyclin D1表达的影响。结果：贝母素乙可显著抑制结肠癌HCT116细胞的增殖能力（P<0.01）,诱导HCT116细胞周期G0/G1期阻滞（P<0.01）,降低CDK4、CDK6和cyclin D1的蛋白表达水平（均P<0.01）。荷瘤小鼠实验结果显示,贝母素乙（0.75 mg/kg）显著抑制HCT116细胞移植瘤的生长并延长荷瘤裸鼠的OS(P<0.05或P<0.01),降低AOM/DSS模型小鼠的体质量、延长OS、减少癌变肠组织...     

HL-60细胞向单核系和粒系分化的比较蛋白质组学研究

背景与目的：已有研究发现NSC67657和全反式维甲酸可以诱导HL-60细胞分别向单核系和粒系分化。本研究比较分析不同诱导剂诱导HL-60细胞向单核系和粒系分化前后以及分化中的蛋白表达差异,发现与单核系和粒系分化有关的关键蛋白。方法：分别采用粒系分化诱导剂全反式维甲酸和单核系分化诱导剂NSC67657诱导HL-60细胞分化,MTT法检测细胞增殖情况：流式细胞技术分析细胞表面特异性分化抗原（CD11b／CD14）的表达,根据CD14表达情况计算细胞分化百分率;细胞化学染色对HL-60的两系分化进行验证。改良双向电泳分离技术对HL-60细胞全蛋白进行分离,PDQuest软件分析寻找差异蛋白点,基质辅助激光解吸-飞行时间质谱（MALDI-TOFMS）对蛋白点进行分析,RT-PCR和免疫印迹对差异蛋白ICAT进行验证。结果：全反式维甲酸和NSC67657均抑制HL-60细胞增殖,并分别诱导HL-60细胞向粒系和单核系分化。在2μmol／LATRA和10μmol／LNSC67657作用5d后．CD11b和CD14的表达均在90％以上,细胞化学染色支持细胞两系分化的结论。蛋白质组学分析表明,HL-60细胞分别向粒系和单核系分化后,有25个差异蛋白点的变化趋势在两系分化中是相同的,有10个差异蛋白点在单核系分化后表达有差异。有15个差异蛋白点在粒系分化后表达有差异：ICAT是其中差异蛋白之一,通过基因和蛋白水平验证．发现ICAT在NSC67657诱导HL-60细胞单核系分化过程中表达升高,而在粒系和非处理细胞中表达无显著性差异。结论：双向电泳／MOLDI-TOFMS对HL-60细胞分化前后细胞全蛋白进行分析．发现了一批与两系分化有关的蛋白分子．为关键蛋白的筛选及其功能研究提供了重要的启示。     

Caffeine inhibits cell proliferation by G0/G1 phase arrest in JB6 cells

Caffeine is a major biologically active constituent in coffee and tea. Because caffeine has been reported to inhibit carcinogenesis in UVB-exposed mice, the cancer-preventing effect of caffeine has attracted considerable attention. In the present study, the effect of caffeine in quiescent (G0 phase) cells was investigated. Pretreatment with caffeine suppressed cell proliferation in a dose-dependent manner 36 h after addition of fetal bovine serum as a cell growth stimulator. Analysis by flow cytometry showed that caffeine suppressed cell cycle progression at the G0/G1 phase, i.e., 18 h after addition of fetal bovine serum, the percentages of cells in G0/G1 phase in 1 mM caffeine-treated cells and in caffeine-untreated cells were 61.7 and 29.0, respectively. The percentage of cells in G0/G1 phase at 0 h was 75.5. Caffeine inhibited phosphorylation of retinoblastoma protein at Ser780 and Ser807/Ser811, the sites where retinoblastoma protein has been reported to be phosphorylated by cyclin-dependent kinase 4 (cdk4). Furthermore, caffeine inhibited the activation of the cyclin D1-cdk4 complex in a dose-dependent manner. However this compound did not directly inhibit the activity of this complex. In addition, caffeine did not affect p16INK4 or p27Kip1 protein levels, but inhibited the phosphorylation of protein kinase B (Akt) and glycogen synthase kinase 3beta. Our results showed that caffeine suppressed the progression of quiescent cells into the cell cycle. The inhibitory mechanism may be due to the inhibition of cell growth signal-induced activation of cdk4, which may be involved in the inhibition of carcinogenesis in vivo.     

阿斯匹林抑制白血病细胞增殖的实验研究

目的以人急性髓细胞性白血病细胞系HL-60为模型,研究非甾体类抗炎药阿斯匹林(ASA)对HL-60细胞生长的影响.方法利用MTT法测定ASA对HL-60细胞的抑制率,并分析剂量反应曲线;通过流式细胞仪(FCM)了解其对细胞周期的影响.结果(1)ASA在浓度为(2.5～10.0)mmol/L作用72h后,HL-60细胞增殖抑制随浓度增加而增加,其IC 50值为8.97mmol/L;并且2.5mmol/L ASA与100μg/ml Ara-c有协同作用;(2)ASA处理后HL-60细胞G0/G1期细胞减少,S期细胞增多.结论结果提示一定浓度ASA在体外能抑制HL-60细胞增殖,抑制率与ASA剂量相关;ASA抑制HL-60细胞增殖可能与其干扰细胞周期有关.     

Effects of calmodulin antagonists and cytochalasins on proliferation and differentiation of human promyelocytic leukemia cell line HL-60

To identify the possible roles of Ca2+-related proteins, calmodulin and microfilaments in leukemic cells, we tested the effect of calmodulin antagonists and cytochalasins on proliferation and differentiation of human promyelocytic leukemic HL-60 cells. The growth of HL-60 was inhibited by N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide, N-(4-aminobutyl)-5-chloro-2-naphthalenesulfonamide, and trifluoperazine dihydrochloride. In contrast, the 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3]-induced differentiation of HL-60, as judged by plasma-membrane antigenic changes detected by monoclonal antibodies (OKM1, OKT9), nitroblue tetrazolium reduction, and induction of phagocytotic capacity, was not inhibited by N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide or N-(4-aminobutyl)-5-chloro-2-naphthalenesulfonamide, although phagocytosis was depressed by N-(6-amino-hexyl)-5-chloro-1-naphthalenesulfonamide or N-(4-aminobutyl)-5-chloro-2-naphthalenesulfonamide. Trifluoperazine dihydrochloride also failed to inhibit the antigenic change induced by 1,25-(OH)2D3. Cytochalasins B and D, microfilament-disrupting agents, inhibited the cytoplasmic division and the growth of HL-60 but did not inhibit the 1,25-(OH)2D3-induced differentiation. These findings suggest that the calmodulin- and microfilament-dependent process may be involved in the proliferation of HL-60, but not in the differentiation induced by 1,25-(OH)2D3.     

Effects of nicotine on cellular proliferation, cell cycle phase distribution, and macromolecular synthesis in human promyelocytic HL-60 leukemia cells

Addition of nicotine causes a dose- and time-dependent inhibition of cell growth in the human promyelocytic HL-60 leukemia cells, with 4 mM nicotine resulting in a 50% inhibition of cellular proliferation after 48-50 h. Accompanying the anticellular effect of nicotine is a significant change in the cell cycle distribution of HL-60 cells. For example, treatment with 4 mM nicotine for 20 h causes an increase in the proportion of G1-phase cells (from 49% to 57%) and a significant decrease in the proportion of S-phase cells (from 41% to 32%). These results suggest that nicotine causes partial cell arrest in the G1-phase which may in part account for its effects on cell growth. To determine whether nicotine changes the cellular uptake/transport to macromolecular precursors, HL-60 cells were treated with 2-6 mM nicotine for 30 h, at the end of which time cells were labeled with [3H]-thymidine, [3H]uridine, [14C]lysine and [35S]methionine, the trichloroacetic acid soluble and insoluble radioactivities from each of the labeling conditions were determined. These studies show that nicotine mainly affects the de novo synthesis of proteins.     

Derivate isocorydine inhibits cell proliferation in hepatocellular carcinoma cell lines by inducing G2/M cell cycle arrest and apoptosis

Tumor Biology - We have previously demonstrated that isocorydine (ICD) can be served as a potential antitumor agent in hepatocellular carcinoma (HCC). A novel derivate of isocorydine (d-ICD) could...     

Amiloride potentiation of differentiation of human promyelocytic cell line HL-60

Cells of the human acute promyelocytic cell line HL-60 undergo differentiation when exposed to dimethyl sulfoxide (DMSO); in this report, amiloride, an inhibitor of passive intracellular Na+ flux, potentiated the DMSO-induced differentiation of HL-60 cells. This effect was seen at several concentrations of DMSO. Amiloride alone did not affect HL-60 differentiation. Various analogues of amiloride were tested for their ability to potentiate differentiation of HL-60 cells. The synergistic induction of myeloid differentiation by a membrane solvent (DMSO) and an Na+ transport inhibitor (amiloride) suggested membrane cation flux as being important in initiating differentiation.     

The ubiquitin-proteasome pathway plays essential roles in ATRA-induced leukemia cells G0/G1 phase arrest and transition into granulocytic differentiation

All-trans retinoic acid (ATRA) has been successfully used in differentiation therapy for acute promyelocytic leukemia (APL) in the clinic. ATRA-induced differentiation of leukemia cells is accompanied by a G0/G1 arrest, yet how ATRA couples cell cycle arrest to differentiation remains largely unknown. Here we observed that the ubiquitin-proteasome pathway (UPP) was activated upon ATRA treatment in the human acute myeloid leukemia cell lines, NB4 and HL-60, as represented by the accumulation of ubiquitinated proteins, the up-regulation of ubiquitin mRNA and increased 20S proteasome activity. Interestingly, we found that complete inhibition of proteasome activity suppressed ATRA-induced proliferation/differentiation (P/D) transition in both cell lines. Furthermore, we demonstrate that the exact protein contributing to this phenomenon is different in these two cell lines. Cyclin-dependent kinase 2 (CDK2) and Cyclin E were degraded by the UPP; they accumulated significantly after complete inhibition of the proteasome in ATRA-treated NB4 and HL-60 cells, respectively. These findings suggested that the UPP might be indispensable in the ATRA-induced G0/G1 arrest and differentiation of leukemia cells. The exact protein degraded by the UPP to promote the myeloid maturation program set in motion by the retinoid may be cell type dependent.     

Arginine deiminase inhibits proliferation of human leukemia cells more potently than asparaginase by inducing cell cycle arrest and apoptosis.

L-Asparaginase is used for the treatment of acute leukemias, but is sometimes ineffective or associated with severe side-effects. We report here that the enzyme arginine deiminase is approximately 100-fold more potent than L-asparaginase in inhibiting the proliferation of cultured human lymphatic leukemia cell lines while it appears to be less effective in leukemia cells of myeloid origin. The inhibition of cell proliferation involves cell growth arrest in the G1- and/or S-phase and eventually apoptotic cell death. Our results suggest the possibility of a future use of arginine deiminase for the therapy of leukemia.