Melatonin induces apoptosis of colorectal cancer cells through HDAC4 nuclear import mediated by CaMKII inactivation

Melatonin induces apoptosis in many different cancer cell lines, including colorectal cancer. However, the precise mechanisms involved remain largely unresolved. In this study, we provide evidence to reveal a new mechanism by which melatonin induces apoptosis of colorectal cancer LoVo cells. Melatonin at pharmacological concentrations significantly suppressed cell proliferation and induced apoptosis in a dose‐dependent manner. The observed apoptosis was accompanied by the melatonin‐induced dephosphorylation and nuclear import of histone deacetylase 4 (HDAC4). Pretreatment with a HDAC4‐specific siRNA effectively attenuated the melatonin‐induced apoptosis, indicating that nuclear localization of HDAC4 is required for melatonin‐induced apoptosis. Moreover, constitutively active Ca²⁺/calmodulin‐dependent protein kinase II alpha (CaMKIIα) abrogated the melatonin‐induced HDAC4 nuclear import and apoptosis of LoVo cells. Furthermore, melatonin decreased H3 acetylation on bcl‐2 promoter, leading to a reduction of bcl‐2 expression, whereas constitutively active CaMKIIα(T286D) or HDAC4‐specific siRNA abrogated the effect of melatonin. In conclusion, the present study provides evidence that melatonin‐induced apoptosis in colorectal cancer LoVo cells largely depends on the nuclear import of HDAC4 and subsequent H3 deacetylation via the inactivation of CaMKIIα.     

Erythematous and reticular forms of oral lichen planus and oral lichenoid reactions differ in pathological features related to disease activity

BACKGROUND: Common clinical forms of oral lichen planus (OLP) and oral lichenoid reactions (OLR) are erythematous (ERY) or reticular (RET). The purpose of this study was to find histopathological changes that differ between these forms. METHODS: Epithelial thickness, epithelial proliferation rate, apoptosis, and HLA-DR expression were compared among 10 reticular and 12 erythematous lesions, and 11 normal oral mucosa samples (NOM). RESULTS: The epithelium in ERY was thinner than in NOM, whereas RET showed values between ERY and NOM. Cell proliferation increased significantly in ERY as compared with RET and NOM, with no difference between RET and NOM. Relative numbers of epithelial cell nuclei displaying visible chromatin condensation were reduced in ERY form. CONCLUSIONS: The markedly increased cell proliferation in ERY supports the notion that this form displays a higher disease activity as compared to RET. It can therefore be important to study each disease form separately.     

Survivin在食管癌中的表达及其与bcl-2表达关系的相关研究

目的探讨Survivin在食管癌组织中的表达及其与bcl-2蛋白表达的相关性。方法应用免疫组织化学SP法,检测Survivin、bcl-2蛋白在68例食管癌组织和20例正常食管组织中的表达。结果Survivin蛋白在正常食管组织中低表达或不表达,68例食管癌组织中,49例表达阳性,占72.1%。Survivin蛋白表达与分化程度、淋巴结转移密切相关(P<0.05)。食管癌组织bcl-2蛋白表达阳性、阴性组中,Survivin蛋白阳性表达率分别为94.7%(36/38)和43.3%(13/30),两者比较,差异有统计学意义(P<0.05)。Survivin蛋白表达与bcl-2蛋白表达密切相关。结论Survivin在食管癌组织中表达上调,通过抑制细胞凋亡,在食管癌的发生中起到重要作用;凋亡相关基因bcl-2的上调与Survivin的表达可能在食管癌变中起协同作用。     

Wortmannin-mediated inhibition of phosphatidylinositol 3-kinase activity triggers apoptosis in normal and neoplastic B lymphocytes which are in cell cycle

The B cell functional response following ligation of surface(s) lgM is dependent upon the differentiation stage of the populationstudied: cross-linking slgM promotes proliferation of restingtonsillar follicular mantle (FM) B lymphocytes but induces apoptosisin the susceptible Epstein- Barr virus genome-negative Burkittlymphoma (BL) cell line Ramos (Ramos-BL). This study investigateswhether phosphatidylinositol-3-kinase (Pl3-kinase), which hasbeen reported to be intimately involved in the regulation ofcellular growth, plays a role in the regulation of these sig-promoted B cell responses, and uses the selective and irreversibleinhibitor of Pl3-kinase activity, wortmannin (Wm). In Ramos-BLB cells, at 8 h post-treatment, Wm triggers a transient increasein apoptosis of 16 ± 6.9% with a concomitant cellularloss of 16 ± 6.1% from the G₁ phase of cell cycle; [³H]thymidineincorporation also decreases by 33 ± 5.0%, from 37,274c.p.m. ± 10% to 25,127 c.p.m. ± 4.0%. Moreover,at 72 h culture, Wm inhibits anti-lgM-induced FM B lymphocytelevels of [³H]thymidine incorporation typically by 47% and triggers80% apoptosis from the G₀G₁ phase of cell cycle. Ramos-BL Bcells exhibit high basal levels of Pl3-kinase activity, as determinedby immunoprecipitation with antibody to the p85 regulatory subunitof Pl3-kinase and ³²P incorporation into phosphatidylinositol,which is not significantly affected by anti-lgM stimulation;by contrast, anti-lgM stimulates significant Pl3-kinase activityover negligible basal levels in FM B lymphocytes. Pre-treatmentwith Wm inhibits Pl3-kinase activity in both cell types. Takentogether these data indicate that in Ramos-BL B cells slgM-triggeredgrowth arrest and apoptosis is Pl3- kinase independent, whereasPl3-kinase activity is critical for slgM-triggered mitogenesisof FM B lymphocytes. Thus Pl3-kinase plays a pivotal role inthe regulation of both normal and neoplastic B lymphocyte progressionthrough the cell cycle, such that if this Pl3-kinase-dependentpathway is inhibited these cells default to apoptosis.     

创伤后肝细胞凋亡与坏死的检测及其意义

目的 探讨严重创伤后肝细胞凋亡及坏死在急性肝功能障碍发病机制中的作用。方法复制多发性骨折合并休克的大鼠创伤模型,采用 Annexin－V－Flous、碘化丙锭(propidium iodid,PI)双标法经流式细胞仪检测创伤后各时间点肝细胞凋亡与坏死的数量变化,结合光镜、电镜和电泳观察细胞凋亡与坏死,并与肝功能变化相比较。结果创伤后早期肝细胞即发生凋亡和坏死,坏死肝细胞的数量进行性升高,与肝功能变化显著呈正相关;凋亡肝细胞在创伤后3h达高峰,部分凋亡肝细胞发生继发性坏死,其数量与肝功能变化显著正相关。结论肝细胞坏死与凋亡是严重创伤后肝功能损害的重要原因,坏死肝细胞是肝功能损害的直接因素,凋亡肝细胞通过发生继发性坏死加重肝功能损害。     

还原型谷胱甘肽在预防糖尿病大鼠勃起功能障碍中的研究

目的探讨还原型谷胱甘肽(GSH)在预防糖尿病大鼠勃起功能障碍中的作用。方法通过腹腔注射链脲佐菌素65mg/kg建立糖尿病大鼠模型,然后随机分成DM组和DM+GSH组,DM+GSH组每天肌肉注射GSH200mg/kg。10周后观察大鼠勃起功能,并获取海绵体组织检测其谷胱甘肽、一氧化氮合酶(NOS)与丙二醛(MDA)水平,用TUNEL法检测细胞凋亡。结果成功建立糖尿病大鼠模型。与未注射GSH的DM组相比,DM+GSH组和正常对照组(C组)勃起功能更好,勃起率分别是20%,62.5%和100%。GSH水平DM+GSH组和C组明显比DM组高,其3组含量每克蛋白分别是(75.83±15.62)、(61.47±8.65)和(35.03±12.29)mg(P<0.05);NOS水平在DM+GSH组每毫克蛋白为(133.9±31.9)U,与正常对照组每毫克蛋白为(142.2±31.2)U相当,但较DM组每毫克蛋白为(58.4±18.9)U高(P<0.05);MDA含量在DM组每毫克蛋白为(3.71±0.62)nmol,明显高于正常对照组和DM+GSH组(P<0.05),这两组每毫克蛋白为(2.08±0.34)nmol和(2.44±0.28)nmol;细胞凋亡率在DM组、DM+GSH组和C组的分别是(22.6±3.6)%、(10.8±1.7)%和(7.2±2.1)%(P<0.05)。结论还原型谷胱甘肽对糖尿病大鼠阴茎组织有较好的抗氧化作用,能减少细胞凋亡,对延缓糖尿病性ED的发生有一定的作用。     

当归对衰老小鼠脑组织细胞凋亡及胸腺指数的影响

目的：研究当归的抗衰老作用及作用机制。方法：用D—半乳糖诱导小鼠制成衰老模型，同时给予不同剂量的当归水煎剂，观察当归对脑组织细胞凋亡及胸腺指数的影响。结果：当归能明显抑制小鼠脑组织细胞凋亡，提高胸腺指数。结论：当归具有抗衰老作用。     

益气复智颗粒对多发脑梗死性痴呆模型大鼠脑组织细胞凋亡的影响

目的 观察益气复智颗粒对多发脑梗死性痴呆模型大鼠脑皮质形态学、细胞凋亡的影响。方法 采用颈内动脉注射血栓的方法，复制多发梗死性痴呆大鼠模型，观察益气复智颗粒12．42g/kg分别于手术前、手术前后、手术后灌胃对实验动物脑皮质形态学、细胞凋亡的影响。结果 益气复智颗粒能使脑缺血后脑内神经细胞凋亡数目下降。结论 益气复智颗粒具有较好的保护脑神经元，阻断脑缺血致神经细胞死亡病理过程的作用。