CDK1 and Cyclin A Expression is Linked to Cell Proliferation and Associated with Prognosis in Non-Hodgkin's Lymphomas

Cellular proliferation is regulated by several kinasic complexes associating cyclins and their catalytic subunits cyclin-dependent kinases (CDKs). In order to gain insight into the mechanisms underlying proliferation in non-Hodgkin's lymphoma (NHL), we examined the expression of certain cell cycle regulatory proteins normally expressed in lymphoid cells, cyclins A, B, D3 and E and cdkl, 2, 4, and 6. In 70 patients presenting a previously untreated lymphoma, cyclins and CDKs were studied by Western blotting and quantified by densitomerry. Flow cytometry study of DNA content was canied out for all patients in order to study cell proliferation and level of ploidy. The results were analysed according to the histological types, the immunological phenotypes of the lymphomas and the outcome of the patients.

Cdk1 and cyclin A were correlated with the percentage of cells in S and S+G2/M phases, and significantly different according to the grade of malignancy, with the lowest expression in low-, and the highest in high-grade NHL according to the Working Formulation. In B-NHLs, cdkl, cyclin A, as well as cdk2, cyclin D3 and E expression was higher in the aneuploid than in the euploid group. Our results point to some particularities of cell cycle regulation in two lymphoma sub-types: I) a low expression of cyclin D3 and cdk6 in mantle cell lymphomas and 2) a discrepancy between the high proliferative activity and the level of protein expression in Burkitt's lymphomas. CDKl and cyclin A showed a significant prognostic value for achievement of complete remission (Cdk 1) and for both disease free (cyclin A) and overall survival (cyclin A and cdkl): low protein level was associated with the best prognosis in B-NHLs.

Our results show that differential cell cycle regulating protein expression may be associated with different biological and clinical behaviour of NHLs and confirm the usefulness of the study of cell cycle regulation as a tool for understanding lymphoid malignancies.     

A Selective Cyclooxygenase-2 Inhibitor Suppresses Tumor Growth in Nude Mouse Xenografted with Human Head and Neck Squamous Carcinoma Cells

The anti-tumor effect of a selective cyclooxygenase (COX)-2 inhibitor, JTE-522, was examined with the human head and neck squamous cell carcinoma cell line KB. KB cells do not produce prostaglandin (PG)-E2. In vitro , JTE-522 induced an increase of G1 phase-arrested cells, suppression of platelet-derived growth factor (PDGF) production and inhibition of telomerase activity. No cytotoxic effect was detected. In vivo , the growth of the tumor xenografted into nude mice was significantly suppressed by JTE-522. Suppression of angiogenesis at the periphery of the tumor, increase of G1-arrested cells and suppression of telomerase activity were observed, together with an increase of apoptotic cell death in the tumor. Immunological enhancement did not play a role. We concluded that the anti-tumor effect of JTE-522 was caused by anti-angiogenesis action, cell cycle arrest and inhibition of telomerase activity of the tumor cells. These combined effects might induce apoptosis.     

Growth Inhibition of A549 Human Lung Adenocarcinoma Cells by L-Canavanine Is Associated with p21/WAF1 Induction

L-Canavanine (CAV) is a higher plant nonprotein amino acid and a potent L-arginine antimetabolite. CAV can inhibit the proliferation of tumor cells in vitro and in vivo, but little is known regarding the molecular mechanisms mediating these effects. We demonstrated that the treatment of human lung adenocarcinoma A549 cells with CAV caused growth inhibition; G1 phase arrest is accompanied by accumulation of an incompletely phosphorylated form of the retinoblastoma protein, whose phosphorylation is necessary for cell cycle progression from G1 to S phase. In addition, CAV induces the expression of p53 and subsequent expression of a cyclin-dependent kinase inhibitor, p21/WAF1. The p53–dependent induction of p21/WAF1 and the following dephosphorylation of the retinoblastoma protein by CAV could account for the observed CAV-mediated G1 phase arrest.     

Effects of ethanol at four phases of the menstrual cycle

RATIONALE: Ovarian hormones, such as estrogen (E) and progesterone (P), interact with neurotransmitters, such as dopamine and gamma-aminobutyric acid, which are thought to be important in mediating the effects of ethanol. Therefore, it is possible that circulating ovarian hormones influence the acute subjective, behavioral, and physiological effects of ethanol, thus indirectly influencing ethanol consumption. OBJECTIVES: To examine the relationship between hormone levels and consumption of ethanol, this study investigated whether the effects of ethanol and the consumption of ethanol vary as a function of menstrual cycle phase. METHODS: Sixteen healthy women with normal menstrual cycles ingested ethanol at four hormonally distinct phases of the menstrual cycle, namely early follicular, late follicular, mid-luteal, and late-luteal. During each session, they first sampled three small doses of ethanol (0.2 g/kg each) at half-hourly intervals. They completed subjective and behavioral tests before the first dose and after each subsequent dose. After consuming the third beverage, the women were allowed to choose up to three additional doses of ethanol (0.2 g/kg), one every 30 min. RESULTS: Ethanol produced subjective effects typical for this drug (such as stimulant-like effects and euphoria), and it impaired eye movements and psychomotor performance. However, the effects of ethanol did not vary according to menstrual cycle phase, and consumption of ethanol also did not vary across the menstrual cycle. CONCLUSIONS: These results suggest that circulating ovarian hormones, like E and P, have little effect on either the acute subjective and behavioral effects of ethanol, or on ethanol consumption.     

血管紧张素Ⅱ和血小板源生长因子对血管平滑肌和心肌细胞细胞周期素及P27蛋白的不同影响

目的　观察血管紧张素Ⅱ (AngⅡ )和血小板源生长因子BB(PDGF BB)对血管平滑肌细胞和心肌细胞中细胞周期素和P2 7蛋白表达量的不同影响。方法　培养的血管平滑肌细胞或乳鼠心肌细胞 ,加入AngⅡ 10 -6 mol/L、PDGF BB 2 0ng/ml后 2 4小时收集细胞 ,用碘化丙啶 (PI)标记细胞DNA ,以确定细胞所处的周期。用细胞周期素 (CyclinD、CyclinE、CyclinA)或P2 7蛋白的单克隆抗体和标记FITC的二抗标记细胞 ,用流式细胞仪测定被激发出的荧光量来测定细胞周期素和P2 7蛋白表达的相对量。结果　AngⅡ除轻度增加心肌细胞CyclinE表达 ( 2 3 9± 4 3对照 8 9± 1 6,P <0 0 1)外 ,对 2种细胞中其他细胞周期素和P2 7蛋白的表达没有明显影响 ,不能促进血管平滑肌细胞和心肌细胞增殖 ;PDGF BB可明显促进 2种细胞中细胞周期素的表达 ,抑制血管平滑肌细胞中P2 7的表达 ( 1 8±1 3、对照 4 8 1± 5 4 ,P <0 0 1) ,但不能抑制心肌细胞P2 7的表达 ( 3 9 4± 5 6、对照 4 4 6± 3 6,P >0 0 5 ) ,因而仅能促进血管平滑肌细胞增殖 ,却不能促进心肌细胞增殖。结论　P2 7蛋白是血管平滑肌细胞和心肌细胞能否进入细胞周期并进行有丝分裂的重要调节因子。     

温热联合细胞周期特异性药物对恶性胸膜间皮瘤细胞的影响

通过体外实验研究温热联合细胞周期特异性药物羟基喜树碱（ＯＰＴ）对ＳＭＣ１ 恶性胸膜间皮瘤细胞株的影响。结果显示：经０１ μｇ／ｍ ｌ、１０ μｇ／ｍ ｌ、１００ μｇ／ｍ ｌＯＰＴ 处理４８ ｈ 对ＳＭＣ１ 细胞增殖有抑制作用,其抑制作用具有药物浓度依赖性,流式细胞仪测定显示经ＯＰＴ处理后细胞周期出现改变,Ｓ期细胞下降,Ｇ２＋ Ｍ 期细胞增加（Ｐ＜ ００５ 或Ｐ＜ ００１）;单独加温３９℃、４１℃、４３℃６０ ｍ ｉｎ 对ＳＭＣ１ 细胞增殖同样具有抑制作用,并有温度依赖性;温热联合ＯＰＴ 对ＳＭＣ１ 细胞增殖具有最佳抑制效果,该效果显现出温度药物浓度依赖性。该实验为临床应用提供了一定的理论依据     

耳穴贴压配合隔姜灸治疗青年妇女经迟的体会

目的观察耳穴贴压配合隔姜灸治疗年轻妇女经迟的疗效。方法选取年轻的经迟女性患者30例,年龄段为20岁~40岁,采用耳穴贴压联合隔姜灸进行治疗。结果总有效率达93.33%。结论耳穴贴压配合隔姜灸治疗年轻妇女经迟的疗效肯定,操作方法简单便捷,临床用药中,未见有毒副作用的案例,方便基层医院推广。     

Cell cycle regulation distinguishes lymphocytes from sporadic and familial Alzheimer's disease patients

Cell cycle (CC) reactivation in neurons seems to underlie the development of Alzheimer's disease (AD). We analyzed whether CC alterations can be detected in immortalized lymphocytes from patients with the sporadic and the familial form of AD (SAD and FAD). Real-time polymerase chain reaction (PCR)-arrays, immunoblotting, and flow cytometry demonstrated differences in the regulation of G1/S phases between SAD lymphocytes and cells from nondemented subjects, as well as between SAD and FAD cells. SAD compared to FAD lymphocytes showed differences in expression profiles of the 90 CC genes, and a marked increase in the level of the p21 protein, which promotes G1-arrest. Accordingly, SAD but not FAD cells had a prolonged G1-phase. γ-secretase inhibition did not change the CC profiles of the cell lines. These data show that SAD involves a prolongation of the G1 phase driven by p21 pathway, which is not activated in FAD cells. Thus, the mechanism in SAD differs from FAD. Moreover, disturbances of the CC in lymphocytes have a potential diagnostic value.     

Cell-cycle analysis and micronuclei frequency reveals G0/G1 blockers as weak micronuclei inducers

Micronuclei (MN) formation is generally attributed to error in DNA synthesis or mitosis, which are represented by the S or G₂/M phase respectively, in the cell-cycle histogram. Interestingly, many of the known anticancer drugs target these cell-cycle phases to elicit cytotoxicity. Here, we attempted to identify whether any correlation exists between the cell-cycle effect and MN induction potential using various treatments. In addition, we tracked down MN in cycling cells to assess its final fate. We treated SiHa cells with various known drugs and correlated their effects on cell-cycle and MN frequency. MN-tracking studies were performed in peripheral mononuclear and siHa cells upon staining with Giemsa and ethidium bromide respectively. We observed MN induction by all the tested drugs irrespective of their basic effect on cell cycle. However, MN induction was more with drugs which interfere with the S or G₂/M than the G₀/G₁ phase. Our results indicate G₀/G₁ blockers to be comparatively safer drugs. Additionally, our results show that expulsion out of cells may be one of the main fates of drug-induced MN.