SRB法检测As_2O_3对KB细胞和Tca8113细胞毒性的研究

目的:采用SRB(Sulforhodamine B)法研究三氧化二砷(As2O3)对人口腔鳞癌KB细胞和Tca8113的细胞毒性。方法:采用SRB法检测As2O3作用于KB细胞和Tca8113细胞前后的A值变化。结果:SRB法检测结果显示在KB组,1、1×10-1、1×10-2、1×10-3、1×10-4μg/mL质量浓度的As2O3所对应的A值分别为0.11、0.21、0.26、0.27、0.27;在Tca8113组,1、1×10-1、1×10-2、1×10-3、1×10-4μg/mL质量浓度的As2O3对应的A值分别为0.48、0.81、0.93、0.97、0.97。结论:As2O3对人口腔鳞癌KB细胞和Tca8113细胞的增殖有明显抑制作用,癌细胞抑制率呈现出剂量依赖性效应关系。     

紫杉醇对人口腔鳞癌KB细胞生长抑制作用及诱导凋亡作用的研究

目的:研究紫杉醇对人口腔鳞癌KB细胞生长抑制及凋亡的作用。方法:MTT方法检测紫杉醇对人口腔鳞癌KB细胞生长抑制率,计算IC50;将0.25,0.5,1μmol·L-1的紫杉醇作用于KB细胞48 h,分别用DAPI染色和流式细胞术检测细胞凋亡,并用免疫印迹法检测紫杉醇对凋亡相关蛋白Bax,Bcl-2和pro-caspase-3的影响。结果:紫杉醇对KB细胞的生长有明显的抑制作用,DAPI染色可见典型的凋亡细胞形态学特征,流式细胞术检测结果表明紫杉醇增加KB细胞凋亡率,免疫印迹结果显示紫杉醇可以增加Bax表达,减少Bcl-2表达,激活caspase-3。结论:紫杉醇对人口腔鳞癌KB细胞有生长抑制和诱导凋亡作用,这可能与抗癌机制有关。     

Contribution of Na(+)/Ca(2+) exchange to excessive Ca(2+) loading in dendrites and somata of CA1 neurons in acute slice

Multiple Ca(2+) entry routes have been implicated in excitotoxic Ca(2+) loading in neurons and reverse-operation of sodium-calcium exchangers (NCX) has been shown to contribute under conditions where intracellular Na(+) levels are enhanced. We have investigated effects of KB-R7943, an inhibitor of reverse-operation NCX activity, on Ca(2+) elevations in single CA1 neurons in acute hippocampal slices. KB-R7943 had no significant effect on input resistance, action potential waveform, or action potential frequency adaptation, but reduced L-type Ca(2+) entry in somata. Nimodipine was therefore included in subsequent experiments to prevent complication from effects of L-type influx on evaluation of NCX activity. NMDA produced transient primary Ca(2+) increases, followed by propagating secondary Ca(2+) increases that initiated in apical dendrites. KB-R7943 had no significant effect on primary or secondary Ca(2+) increases generated by NMDA. The Na(+)/K(+) ATPase inhibitor ouabain (30 microM) produced degenerative Ca(2+) overload that was initiated in basal dendrites. KB-R7943 significantly reduced initial Ca(2+) increases and delayed the propagation of degenerative Ca(2+) loads triggered by ouabain, raising the possibility that excessive intracellular Na(+) loading can trigger reverse-operation NCX activity. A combination of NMDA and ouabain produced more rapid Ca(2+) overload, that was contributed to by NCX activity. These results suggest that degenerative Ca(2+) signaling can be triggered by NMDA in dendrites, before intracellular Na(+) levels become sufficient to reverse NCX activity. However, since Na(+)/K(+) ATPase inhibition does appear to produce significant reverse-operation NCX activity, this additional Ca(2+) influx pathway may operate in ATP-deprived CA1 neurons and play a role in ischemic neurodegeneration.     

New therapeutic targets in immune disorders: ItpkB,Orai1 and UNC93B

Background: Sequencing of the murine and human genomes has enabled large-scale functional genomics approaches to target identification. This holds the promise of drastically accelerating target discovery. Moreover, by providing an initial validation coincident with target identification, cell based cDNA or small interfering RNA (siRNA) screens and in particular genome-wide in vivo approaches, including forward or reverse genetics and analyses of natural gene polymorphisms, can move the relatively late step of target validation to the beginning of the process, reducing the risk of pursuing targets with little in vivo relevance. Objective: We critically discuss the value of combining functional genomics with traditional approaches for accelerating target identification and validation. Methods: We evaluate the potentials of inositol (1,4,5)trisphosphate 3-kinase B (ItpkB), Orai1 and UNC93B, three particularly interesting proteins that were recently identified through functional genomics, as targets in immune disorders. Results/conclusion: Combining functional genomics with traditional approaches can accelerate target discovery and validation, but requires a follow-up platform that integrates and analyzes all relevant data for assessment of the clinical potential of the growing number of novel targets.     

鼻腔鳞状细胞癌中NF-KB的表达及其临床生物学意义

目的:探讨核转录因子KB(NF-KB)在鼻腔鳞状细胞癌及癌旁组织的的表达及临床意义。方法:采用免疫组织化学链霉菌抗生素过氧化物酶(SP)法检测36例鼻腔鳞状细胞癌组织及癌旁组织中NF-KB的表达情况。结果:鼻腔鳞状细胞癌NF-KB的阳性表达率为91.6%,明显高于癌旁组织16.6%(P<0.05),差异有统计学意义,在鼻腔鳞状细胞癌组织中,NF-KB表达水平与其病理分级和临床分期密切相关。结论:NF-KB的表达增高与鼻腔鳞状细胞癌的发生、发展相关。     

Development of the Thyroid Hormone Receptor β‐Subtype Agonist KB‐141 : A Strategy for Body Weight Reduction and Lipid Lowering with Minimal Cardiac Side Effects

Few treatments for obesity exist and improvements for treatment of hyperlipidemia are still desirable. Thyroid hormone receptors (TRs) regulate body weight, adiposity, and cholesterol levels. However, thyroid hormones can have deleterious effects, particularly cardiac acceleration, that limits the use of hormones in the treatment of obesity. There is evidence that the TRβ subtype mediates lowering of blood cholesterol levels and possibly elevation of metabolic rate, whereas TRα appears to control heart rate. In studies, described in this review article, we examined the effects of selective TRβ activation on metabolic rate and heart rate in mice, rats and monkeys. T₃ had a greater effect on increasing heart rate in wild type (WT) than in TRα‐/‐ mice (ED₁₅ values of 34 and 469 nmol/kg/day, respectively). T₃ increased metabolic rate (MVO₂) in both WT and TRα‐/‐ mice, but the effect on TRα‐/‐ mice was less pronounced compared to WT mice. Stimulation of MVO₂ is mediated by both TRα and TRβ, but with different profiles. In cholesterol‐fed rats, KB‐141, a selective TRβ agonist, increased MVO₂ with a 10‐fold selectivity and lowered cholesterol with a 27‐fold selectivity vs. tachycardia. In primates, KB‐141 caused significant, cholesterol, Lp(a) and body weight reduction after 1 week of treatment with no effect on heart rate. These data suggest that selective TRβ agonists may represent a novel class of drugs for the treatment of obesity, hypercholesterolemia and elevated Lp(a), which may make them useful therapeutics for patients with metabolic syndrome.     

c-myc异常表达与KB细胞多药耐药性的关系及其意义

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rsfMRI effects of KB220Z™ on neural pathways in reward circuitry of abstinent genotyped heroin addicts

Recently, Willuhn et al. reported that cocaine use and even non-substance-related addictive behavior increases as dopaminergic function is reduced. Chronic cocaine exposure has been associated with decreases in D2/D3 receptors and was also associated with lower activation of cues in occipital cortex and cerebellum, in a recent PET study by Volkow’s et al. Therefore, treatment strategies, like dopamine agonist therapy, that might conserve dopamine function may be an interesting approach to relapse prevention in psychoactive drug and behavioral addictions. To this aim, we evaluated the effect of KB220Z? on reward circuitry of 10 heroin addicts undergoing protracted abstinence (average 16.9 months). In a randomized placebo-controlled crossover study of KB220Z, five subjects completed a triple-blinded experiment in which the subject, the person administering the treatment, and the person evaluating the response to treatment were blinded to the treatment that any particular subject was receiving. In addition, nine subjects were genotyped utilizing the GARS_DX? test. We preliminarily report that KB220Z induced an increase in BOLD activation in caudate-accumbens-dopaminergic pathways compared to placebo following 1-hour acute administration. Furthermore, KB220Z also reduced resting-state activity in the putamen of abstinent heroin addicts. In the second phase of this pilot study of all 10 abstinent heroin-dependent subjects, we observed that three brain regions of interest were significantly activated from resting state by KB220Z compared to placebo (p < 0.05). Increased functional connectivity was observed in a putative network that included the dorsal anterior cingulate, medial frontal gyrus, nucleus accumbens, posterior cingulate, occipital cortical areas, and cerebellum. These results and other quantitative electroencephalogy (qEEG) study results suggest a putative anti-craving/anti-relapse role of KB220Z in addiction by direct or indirect dopaminergic interaction. Due to small sample size, we caution definitive interpretation of these preliminary results, and confirmation with additional research and ongoing rodent and human studies of KB220Z is required.