27-Hydroxycholesterol modulates lung cancer cell proliferation by activation of LXR signaling pathway

AIM:To investigate the effect of cholesterol metabolite 27-hydroxycholesterol (27-OHC) on the proliferation of lung cancer cells. METHODS:Human lung cancer A549 cells were treated with 27-OHC at different concentrations (0, 0.3125, 0.625, 1.25, 2.5, 5 and 10 μmol/L) for 24~48 h. The cell viability, cell cycle, cell prolife-ration, the intracellular cholesterol levels and cholesterol metabolism-related molecule expression were subsequently assessed by CCK-8 assay, flow cytometry, EdU staining, tissue total cholesterol detection kit, real-time PCR and Western blot. RESULTS:27-OHC decreased the viability of the A549 cells in a dose-and time-dependent manner (P<0.01) and inhibited the cell proliferation (P<0.05). The expression of typical liver X receptor (LXR) downstream target proteins including ATP-binding cassette transporter A1 (ABCA1), low-density lipoprotein receptor (LDLR), and 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMG-CR) were modulated, which promoted the efflux of intracellular cholesterol, and reduced cholesterol influx and de novo synthesis, resulting in decreased intracellular cholesterol levels and cell viability. Furthermore, the inhibitory effect of 27-OHC on A549 cell viability was significantly attenuated after the LXR pathway was partially blocked by 5 μmol/L GSK2033 treatment (P<0.05). CONCLUSION:27-OHC inhibits A549 cell prolife-ration via activation of LXR signaling pathway.     

PPARγ mediates effects of diosgenin on proliferation and apoptosis in human glioblastoma U87MG cells

AIM:To investigate the effect of diosgenin (Dio) on the proliferation, apoptosis and expression of peroxisome proliferator-activated receptor γ (PPARγ) in human glioblastoma U87MG cells and its possible mechanism. METHODS:Human astrocytes (HA) and U87MG cells were cultured in vitro and treated with Dio (0, 10, 20, 30, 40 and 50 μmol/L) and GW9662 (5 μmol/L) for 48 h, and then the cell viability was detected by CCK-8 assay. Cell colony formation assay was used to assess the proliferation potential. Flow cytometry was used to analyze the cell cycle distribution and apoptosis. The mRNA expression level of PPARγ was measured by RT-PCR. Western blot was used to determine the protein levels of PPARγ, cyclin D1, cyclin E1, Bcl-2 and Bax. RESULTS:Dio had no significant influence on the viabi-lity of HA (P>0.05). However, Dio remarkably reduced the viability of U87MG cells in a dose-dependent manner (P<0.05) with IC₅₀ of 24.31 μmol/L. Meanwhile, Dio remarkably diminished colony formation ability (P<0.05), induced G₀/G₁ phase arrest of the cell cycle and apoptosis (P<0.05), up-regulated the expression of PPARγ at mRNA and protein levels, increased the protein level of Bax (P<0.05), and down-regulated the protein levels of cyclin D1, cyclin E1 and Bcl-2 (P<0.05) in a dose-dependent manner. However, these effects induced by Dio were inhibited by GW9662 (P<0.05), a specific inhibitor of PPARγ. CONCLUSION:Dio may inhibit proliferation and induce apoptosis in human glioblastoma U87MG cells most likely via up-regulating the expression of PPARγ, and then down-regulating the protein levels of cyclin D1, cyclin E1 and Bcl-2, and up-regulating the protein level of Bax.     

FAM3C activates Akt to promote viability of oral squamous-cell carcinoma cells

AIM: To investigate the expression and roles of family with sequence similarity 3, member C (FAM3C) in oral squamous-cell carcinoma cells. METHODS: The mRNA and protein expression levels of FAM3C in dysplastic oral keratinocyte (DOK) and oral squamous-cell carcinoma WSU-HN6 cells were detected by RT-qPCR and Western blot. The WSU-HN6 cells were treated with siFAM3C or FAM3C antibody. After 24, 48 and 72 h, the viability of WSU-HN6 cells was measured by CCK-8 assay, and the activation of protein kinase B (Akt) was detected by Western blot. Adenovirus was used to mediate over-expression of FAM3C in the DOK cells. The DOK cell viability was measured by CCK-8 assay after adenovirus infection for 24, 48 and 72 h, and the activation of Akt was detected by Western blot. RESULTS: Compared with the DOK cells, the mRNA and protein levels of FAM3C were significantly increased in the WSU-HN6 cells (P<0.05). The viability of WSU-HN6 cells transfected with siFAM3C was significantly inhibited at 48 h and 72 h (P<0.05). siFAM3C treatment inhibited the activation of Akt (P<0.05). FAM3C antibody treatment also suppressed the viability of the WSU-HN6 cells at 48 h and 72 h and the activation of Akt (P<0.05). Over-expression of FAM3C in the DOK cells promoted the cell viability at 48 h and 72 h and activated Akt (P<0.05). CONCLUSION: FAM3C might promote oral squamous-cell carcinoma cell growth by activating Akt.     

miR-204 inhibits proliferation of Hodgkin lymphoma cells by targeting Sirt1/p53 signaling pathway

AIM: To investigate the effect of microRNA-204 (miR-204) on the proliferation of Hodgkin lymphoma cells and the underlying mechanism. METHODS: The expression of miR-204 and Sirt1 mRNA in Hodgkin lymphoma tissues was detected by RT-qPCR. After transfection with miR-204 mimic, Sirt1 siRNA and miR-204 mimic+pcDNA3.1-Sirt1 into the L428 cells, the cell viability and BrdU incorporation were measured by CCK-8 assay and BrdU assay, respectively. The protein levels of Sirt1 and acetylated p53 (ac-p53) were determined by Western blot.The targeting relationship between miR-204 and Sirt1 was verified by double luciferase reporter assay. RESULTS: The low expression of miR-204 and the high mRNA expression of Sirt1 were found in the Hodgkin lymphoma tissues. Compared with control group, the cell viability, BrdU incorporation and the protein levels of Sirt1 and ac-p53 were significantly decreased after L428 cells were transfected with miR-204 mimic or Sirt1 siRNA (P<0.05). Compared with miR-204 mimic alone group, the cell viability, BrdU incorporation and the protein levels of Sirt1 and ac-p53 were increased after L428 cells were co-transfected with miR-204 mimic and pcDNA3.1-Sirt1 (P<0.05). The results of double luciferase reporter assay confiermed that Sirt1 was the target gene of miR-204. CONCLUSION: The inhibitory effect of miR-204 on the proliferation of L428 cells may be achieved by inhibiting the expression of Sirt1 and promoting the up-regulation of ac-p53.     

F-box domain is involved in regulating the proliferation of MCF-7 cells by FBXO39 protein

AIM: To investigate the effect of F-box domain on the regulation of MCF-7 cell proliferation by FBXO39 protein. METHODS: The effect of F-box domain on the localization of FBXO39 protein in the MCF-7 cells was investigated. MCF-7 cell cDNA library was used as the template resource. The full-length cDNA sequence of FBXO39 was amplified by PCR method and subcloned into eukaryotic expression vector pEGFP-C2. The pEGFP-FBXO39ΔF (F-box domain deletion mutation) plasmid was successfully constructed with the template resource of pEGFP-FBXO39 plasmid. The recombinant plasmids were transfected into the MCF-7 cells, and then the expression of FBXO39 and FBXO39ΔF were determined by Western blot. The cellular localization of FBXO39 and FBXO39ΔF were observed by confocal microscopy. The localization of endogenous FBXO39 in the MCF-7 cells was detected by immunofluorescence staining. In addition, MTT and EdU assays were used to measure the cell proliferation, flow cytometry was used to measure the cell cycle distribution, and immunohistochemical staining was used to observe the expression of FBXO39 in the breast cancer and para-carcinoma tissues. RESULTS: The eukaryotic expression vector pEGFP-FBXO39 and pEGFP-FBXO39ΔF were constructed successfully. F-box domain had no effect on the cell localization of FBXO39. FBXO39 promoted MCF-7 cell proliferation but FBXO39ΔF did not. FBXO39 was highly expressed in the breast cancer tissues. CONCLUSION: F-box domain had no effect on the cellular localization of FBXO39 protein. However, it plays an important role in the biological function of FBXO39. FBXO39 may be related to breast cancer tumorigenesis.     

高二氧化碳结合低氧处理对杏鲍菇细胞壁的影响

旨在研究高二氧化碳结合低氧处理对杏鲍菇细胞壁成分（蛋白质、多糖、几丁质）、咀嚼度及超微结构的影响。在温度（22±1）℃、相对湿度90％～95％的条件下,以空气为对照（CK）,采用气调（CA,2％O2＋30％CO2）对杏鲍菇进行货架期试验。结果表明,货架期间CA的咀嚼度显著高于CK。 CA可以有效延缓杏鲍菇细胞壁水溶性蛋白质和1 mol/L NaOH可溶性蛋白质的降解,维持了细胞壁总蛋白质含量及细胞壁结构完整。 CA有效抑制杏鲍菇多糖含量的下降,其对水溶性多糖、10 mol/L NaOH可溶性多糖分解的抑制作用较为明显。此外,CA显著促进了水溶性几丁质、10 mol/L NaOH可溶性几丁质、HCl/1 mol/L NaOH可溶性几丁质的积累,延缓其分解,有效抑制了杏鲍菇细胞壁几丁质含量的下降,有助于维持其硬度及咀嚼度。杏鲍菇超微结构结果也表明, CA保持杏鲍菇细胞壁结构的完整性与稳定性,较好地维持杏鲍菇咀嚼度。综上所述,CA通过影响菇体细胞壁的代谢来保持杏鲍菇的食用品质。     

基于细胞多层介电模型的脉冲电场生物学效应研究

为确定脉冲电场生物学效应的电场参数,从细胞多层介电模型出发,通过研究其等效电路模型在外加电场中生物响应的仿真分析得出植物细胞外膜具有低通滤波特性,内膜具有带通滤波特性。同时对细胞外膜跨膜电压进行时域分析表明频率小于2.83 Hz、电场强度大于69.7 kV/m、ms/μs级脉宽的极低频脉冲电场可以在植物细胞外膜产生可逆电穿孔。采用电场强度为100 kV/m、频率为1 Hz、脉宽为80 ms的极低频脉冲电场处理萌发绿豆种子,在萌发第4 d时,绿豆种子的芽长和根长分别比对照组增加了65.8%和80.2%。     

一种土壤微生物总DNA的高效提取方法

获得高浓度、大片段、多样性程度高的土壤微生物总DNA 是研究土壤微生物群落结构的分子生态学基础。本文采用间接法(菌体细胞回收法)提取红壤地区两种土壤类型的土壤微生物总DNA,定量计算其回收率,并与直接法(细胞原位裂解法)比较了提取效率和纯度。结果表明:红壤地区2种土壤每克干土的总DNA提取量,间接法约为0.34和0.53礸/g干土,直接法约为13.62和24.32礸/g干土;间接法的提取效率低于直接法,但所得DNA片段较大,且Sau 3AⅠ 酶切和16 S rDNA通用引物PCR扩增结果显示,间接法比直接法更能有效地去除土壤中的某些抑制剂,所得总DNA的纯度更高,有利于后续操作。     

水分胁迫期间及解除胁迫后对胡萝卜生长及叶细胞结构的影响

以盆栽胡萝卜品种向阳二号为材料,研究不同程度水分胁迫及胁迫解除后对胡萝卜生长的影响,旨在为胡萝卜耐旱栽培提供理论依据。结果表明,水分胁迫对胡萝卜的生长影响很大,当缺水严重时,叶片及根的生长均受到明显抑制,使苗的生长量、干物质积累及含水量显著下降。而且即使解除胁迫后其生长及各项指标也难以恢复。水分胁迫对叶细胞结构也有很大影响,随着水分胁迫程度的增强,细胞核数量减少,核缩小、变形或降解,解除胁迫以后也很难恢复。