Enrichment of breast cancer stem cells using a keratinocyte serum-free medium

Background  Keratinocyte serum-free medium (K-SFM) is a defined medium used to support the growth of primary keratinocytes and embryonic stem cell. The aim of this research was to optimize enrichment of breast cancer stem cells (CSCs) using K-SFM.

Methods  A K-SFM was used to enrich CSCs from two breast cancer cell lines and a primary culture of breast cancer. RPMI-1640 supplemented with 10% fetal calf serum (FCS) was used as a control. CSCs were identified with flow cytometry using CD44⁺/CD24^– as molecular markers. The expression of a variety of CSC markers (Oct-4, ABCG2, Nanog, N-cadherin, and E-cadherin) was analyzed with real-time PCR.

Results  Much higher percentage of CSCs was achieved with K-SFM: 17.3% for MCF-7 cells, 17.4% for SKBR-3, and 20.0% for primary breast cancer culture. Less than 1% CSC was achieved using RPMI-1640 supplemented with 10% FCS. In comparison to the CSCs obtained with RPMI-1640, CSCs in the K-SFM expressed higher levels of Oct-4, ABCG2, Nanog and N-cadherin, and lower level of E-cadherin.

Conclusion  K-SFM is an optimal culture medium to maintain and to enrich breast CSCs.

     

Enhanced invasion in vitro and the distribution patterns in vivo of CD133+ glioma stem cells

Background  Recent studies have suggested that cancer stem cells cause tumor recurrence based on their resistance to radiotherapy and chemotherapy. Although the highly invasive nature of glioblastoma cells is also implicated in the failure of current therapies, it is not clear whether cancer stem cells are involved in invasiveness. This study aimed to assess invasive ability of glioma stem cells (GSCs) derived from C6 glioma cell line and the distribution patterns of GSCs in Sprague-Dawley (SD) rat brain tumor. 

Methods  Serum-free medium culture and magnetic isolation were used to gain purely CD133⁺ GSCs. The invasive ability of CD133⁺ and CD133^– C6 cells were determined using matrigel invasion assay. Immunohistochemical staining for stem cell markers and luxol fast blue staining for white matter tracts were performed to show the distribution patterns of GSCs in brain tumor of rats and the relationship among GSCs, vessels, and white matter tracts. The results of matrigel invasion assay were estimated using the Student’s t test and the analysis of Western blotting was performed using the one-way analysis of variance (ANOVA) test.

Results  CD133⁺ GSCs (number: 85.3±4.0) were significantly more invasive in vitro than matched CD133^– cells (number: 25.9±3.1) (t=14.5, P <0.005). GSCs invaded into the brain diffusely and located in perivascular niche of tumor-brain interface or resided within perivascular niche next to white fiber tracts. The polarity of glioma cells containing GSCs was parallel to the white matter tracts.

Conclusions  Our data suggest that CD133⁺ GSCs exhibit more aggressive invasion in vitro and GSCs in vivo probably disseminate along the long axis of blood vessels and transit through the white matter tracts. The therapies targeting GSCs invasion combined with traditional glioblastoma multiforme therapeutic paradigms might be a new approach for avoiding malignant glioma recurrence.

     

Abnormal expression of CD43 in patients with systemic lupus erythematosus and its clinical significance

Background  Previous studies indicate that CD43 plays a role in regulating the adhesion of lymphocytes, cell mutation and activation, however, little is known about its effect on systemic lupus erythematousus (SLE). This study was designed to explore the clinical significance of CD43 in SLE patients.

Methods  We used microarray and real-time PCR to detect the mRNA and protein expression of magnetic bead sorted T cells and B cells from peripheral blood mononuclear cells (PBMCs) of SLE patients, and analyzed the relationship between CD43 and the clinical indexes.

Results  Both microarray and real-time PCR results showed that CD43 mRNA was significantly decreased in PBMCs of SLE patients compared with healthy controls (P <0.001). There were no significant differences between lupus nephritis and non-lupus nephritis patients, and neuropsychiatric and non-neuropsychiatric patients. CD43 mRNA expression was significantly reduced in T cells but not in B-cells in SLE patients compared to healthy controls (P <0.01). Compared with healthy controls, the percentage of CD43⁺ cells in the PBMCs of SLE was significantly decreased (P=0.004), and the CD43 fluorescence intensity in CD3⁺/CD43⁺ cells and CD19⁺/CD43⁺ cells was also significantly weaker than in healthy controls (P=0.039 and 0.003). There was no significant difference in the percentage of CD3⁺/CD43⁺ cells, CD19⁺/CD43⁺ cells between the two groups. The CD43 fluorescence intensity in CD3⁺/CD43⁺ cells was inversely correlated with the levels of IgG and IgM (r= –0.8 and –0.6).

Conclusions  Compared to healthy controls, both CD43 mRNA and protein expressions were reduced in T cells from patients with SLE, and were inversely correlated with IgG.

     

Inhibiting effect of Astragalus polysaccharides on the functions of CD4+CD25highTreg cells in the tumor microenvironment of human hepatocellular carcinoma

Background  Astragalus polysaccharides (APS), the main active extract from Astragalus membranaceus (a traditional Chinese medicinal herb), is associated with a variety of immunomodulatory activities. The purpose of the present study was to examine the effect of APS on the function of Treg cells in the tumor microenvironment of human hepatocellular carcinoma (HCC) and to identify the pharmacologic mechanism of APS responsible for the anti-chemotactic activity in CD4⁺CD25^highTreg cells in tumor site of HCC.

Methods  The prevalence of Treg in fresh tissue samples from 31 patients with HCC after radicalhepatectomy was detected. CD4, CD25 and CD127 were selected as Treg cell makers to phenotype cell populations. The expression of FOXp3 mRNA was also analyzed. The migration and proliferation of Treg cells were observed. Interleukin (IL)-4, IL-10, IFN-γ and SDF-1 in cell supernatant were detected. For all tests, functions of Treg cells were evaluated after treatment with APS.

Results  APS can inhibit the growth and proliferation of CD4⁺CD25⁺Treg cells in vitro in a dose- and time-dependent manner. APS may inhibit CD4⁺CD25⁺Treg cells through restoring the cytokine imbalance and reducing the expression of FOXp3 in local HCC microenvironments. SDF-1 played an important role in there recruitment of Treg cells into the tumor microenvironment of HCC. APS might have inhibiting effects on Treg cell migration by blocking SDF-1 or its receptor through the CXCR4/CXCL12 pathway.

Conclusions  The increase in numbers of tumor associated Treg cells might play a role in modulation of the immune response against HCC. APS can restore the cytokine balance in the tumor micro environment and suppress the expression of FOXp3 mRNA to inhibit the immune suppressive effects of Treg cells. The application of APS in the tumor microenvironment might act to enhance the anti-tumor effects of the immunotherapy-based methods, and consequently to increase the survival rate in HCC.

     

HLA-DR expression on regulatory T cells is closely associated with the global immune activation in HIV-1 infected subjects naïve to antiretroviral therapy

Background  The frequencies of regulatory T cells (Tregs) increased over the HIV infection but its counts actually decreased. We proposed that the decrease of Treg counts may cause the reduction of inhibitory effect and thereby account for the over-activation of Tregs during HIV infection. However, it remains unknown whether Tregs are also over-activated and thereafter the activation induced death may lead to the decrease of Tregs.

Methods  Tregs were defined as CD4⁺CD25⁺CD127^lo/- T cells. Eighty-one HIV-1 infected patients were enrolled in our study, and twenty-two HIV-1 seronegative donors were recruited as the control. The levels of HLA-DR on Tregs were determined by FACSAria flow cytometer.

Results  Compared to HIV-1 seronegative donors, the levels of HLA-DR on CD4⁺CD25⁺CD127^lo/- Tregs were significantly increased in HIV-1 infected patients, and its increase was positively associated with viral loads (r=0.3163, P=0.004) and negatively with CD4 T-cell counts (r=−0.4153, P <0.0001). In addition, significant associations between HLA-DR expression on CD4⁺CD25⁺CD127^lo/- Tregs and the percentages of HLA-DR, CD38, Ki67 expressing CD4⁺ and CD8⁺ T cells were also identified.

Conclusion  HLA-DR on Tregs is a good marker for viral replication and disease progression. The over-activation of Tregs might result in the decrease of Tregs.

     

Receptor activator of nuclear factor kappa B ligand and osteoprotegerin expression in chronic apical periodontitis: possible association with inflammatory cells

Background  Receptor activator of nuclear factor kappa B (NF-κB) ligand (RANKL) and osteoprotegerin (OPG) have been recently shown to play important roles in bone resorption. The aim of this study was to investigate the possible association between the expression of bone resorption regulators (RANKL and OPG) and inflammatory cell infiltration in chronic apical periodontitis.

Methods  The samples of chronic periapical lesions (n=40) and healthy periapical tissues (n=10) were examined for immunohistochemical analysis of RANKL and OPG. Lesion samples were further analyzed for the inflammatory infiltration condition. The inflammatory cell infiltration was scored in relation to immunohistochemical reactivity for CD3, CD20 and CD68.

Results  The number of RANKL-positive cells and the ratio of RANKL/OPG in chronic apical periodontitis were significantly higher than those in healthy periapical tissues (P <0.001). The number of RANKL-positive cells was higher in lesions with severe inflammatory infiltration than in those with light inflammatory infiltration (P <0.05). Significantly increased RANKL expression was found with T lymphocytes (CD3⁺), macrophages (CD68⁺) and B lymphocytes (CD20⁺) infiltration (P <0.05). No association was found between the ratio of RANKL/OPG and inflammatory cell infiltration.

Conclusions  RANKL expression was increased with T, B lymphocytes and macrophages infiltration, respectively in chronic periapical lesions. RANKL appears to be closely related to periapical inflammatory infiltrates. The relative ratio of RANKL/OPG may be a key determinant of RANKL-mediated bone resorption.

     

Role of C6ORF120, an N-glycosylated protein, is implicated in apoptosis of CD4+ T lymphocytes

Background  Although CD4⁺ T cell apoptosis and CD8⁺ T cell responses have been extensively studied during HIV infection, how apoptosis signals being initiated in CD4⁺ T cells still need to be elucidated. The present study was designed to characterize the function-unknown gene, C6orf120, and elucidates its primary role in tunicamycin-induced CD4⁺ T apoptosis.

Methods  The C6orf120 coding sequence was amplified from peripheral blood mononuclear cells (PBMCs) total RNA of AIDS patients. The DNA fragment was inserted into the pET-32a expression system, transformed into Escherichia coli, and preparation of C6ORF120 recombinant protein. The magnetic cell separation technology was used to prepare primary CD4⁺ T cells and CD8⁺ T cells. The primary T cells were cultured at 1 × 10⁶ cells/ml, treated with 0, 0.1, 1, 10, 100, and 200 ng/ml of C6orf120 recombinant protein for 48 hours, then harvested for cell cycle and apoptosis analysis. Tunicamycin (0.5 μmol/L) was used to induce endoplasmic reticulum stress in Jurkat cells. The biomarker 78 KDa glucose-regulated protein (GRp78) and growth arrest and DNA damage (GADD) were used to evaluate endoplasmic reticulum stress of Jurkat cells.

Results  We prepared C6ORF120 recombinant protein and its polyclonal antibody. Immunohistochemical analysis showed that C6orf120 mainly expressed in hepatocytes and cells in germinal center of lymph node. At concentration of 0.1, 1, 10, 100, and 200 ng/ml, C6orf120 recombinant protein could induce apoptosis of Jurkat cells and primary CD4⁺ T cells, and promoting G2 phase of its cell cycle. Western blotting analysis showed that C6ORF120 recombinant protein increased the expression of GRp78 and GADD in Jurkat cells in vitro.

Conclusion  Our results suggested that C6ORF120 could induce apoptosis of CD4⁺ T cells, at least in part, mediated with endoplasmic reticulum stress.

     

Immature CD4+ dendritic cells conditioned with donor kidney antigen prolong renal allograft survival in rats

Background  Allogeneic transplant rejection is currently a major problem encountered during organ transplantation. The dendritic cell (DC) is the most effective powerful known professional antigen-presenting cell, and recent studies have found that DCs can also induce immune tolerance, and avoid or reduce the degree of transplant rejection. The aim of this study was to evaluate the effect of transfused immature CD4⁺ DCs on renal allografts in the rat model.

Methods  In this study, we induced CD4⁺ immature DCs from rat bone marrow cells by a cytokine cocktail. The immature CD4⁺ DCs were identified by morphological analysis and then the suppressive activity of these cells conditioned with donor kidney antigen was evaluated in vitro and in vivo.

Results  Immature CD4⁺ DCs conditioned with donor kidney antigen possessed immunosuppressive activity in vitro and they were able to prolong renal transplant survival in an allograft rat model in vivo.

Conclusions  Our study provides new information on efficacious renal transplantation, which might be useful for understanding the function of immature CD4⁺ DCs in modulating renal transplant rejection and improving clinical outcome in future studies.

     

Coexistence of Th1/Th2 and Th17/Treg imbalances in patients with allergic asthma

Background  Recent recognition is that Th2 response is insufficient to fully explain the aetiology of asthma. Other CD4⁺ T cells subsets might play a role in asthma. We investigated the relative abundance and activities of Th1, Th2, Th17 and CD4⁺CD25⁺ Treg cells in patients with allergic asthma.

Methods  Twenty-two patients with mild asthma, 17 patients with moderate to severe asthma and 20 healthy donors were enrolled. All patients were allergic to house dust mites. Plasma total IgE, pulmonary function and Asthma Control Questionnaire were assessed. The proportions of peripheral blood Th1, Th2, Th17 and CD4⁺CD25⁺ Treg cells were determined by flow cytometry. The expression of cytokines in plasma and in the culture supernatant of peripheral blood mononuclear cells was determined by enzyme linked, immunosorbent assay.

Results  The frequency of blood Th2 cells and IL-4 levels in plasma and culture supernatant of peripheral blood mononuclear cells were increased in all patients with allergic asthma. The frequency of Th17 cells and the plasma and culture supernatant levels of IL-17 were increased, whereas the frequency of CD4⁺CD25⁺ Treg cells and plasma IL-10 levels were decreased in patients with moderate to severe asthma. Dermatophagoides pteronyssinus specific IgE levels were positively correlated with the percentage of blood Th2 cells and plasma IL-4 levels. Forced expiratory volume in the first second was negatively correlated with the frequency of Th17 cells and plasma IL-17 levels, and positively correlated with the frequency of Treg cells. However, mean Asthma Control Questionnaire scores were positively correlated with the frequency of Th17 cells and plasma IL-17 levels, and negatively correlated with the frequency of Treg cells.

Conclusions  Imbalances in Th1/Th2 and Th17/Treg were found in patients with allergic asthma. Furthermore, elevated Th17 cell responses, the absence of Tregs and an imbalance in Th17/Treg levels were associated with moderate to severe asthma. 

     

Polymorphisms of dihydropyrimidine dehydrogenase gene and clinical outcomes of gastric cancer patients treated with fluorouracil-based adjuvant chemotherapy in Chinese population

Background  Dihydropyrimidine dehydrogenase (DPD), a key enzyme involved in the catabolism of 5-fluorouracil (5-FU), is the attractive candidate for pharmacogenetic research on efficacies and toxicities of 5-FU. The aim of this study is to explore the association between polymorphisms of dihydropyrimidine dehydrogenase gene (DPYD) and clinical outcomes of gastric cancer patients treated with fluorouracil-based adjuvant chemotherapy in the Chinese population.

Methods  Three hundred and sixty-two patients with gastric cancer in the Chinese population were treated with fluorouracil-based adjuvant chemotherapy. The single nucleotide polymorphic genotypes of DPYD were determined by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF-MS) using DNA samples isolated from peripheral blood collected before treatment.

Results  The average response rate for chemotherapy was 46.7%. A significantly different distribution of the rs1801159 (c²=8.76, P=0.012) genotypes was observed. Homozygous genotype rs1801159A/A was over-represented in responsive patients. Conversely, carriers of the rs1801159A/G genotype were prevalent in non-responsive patients. In the haplotype association analysis, there was significant difference in global haplotype distribution between the groups (c²=3.96, P=0.0465).

Conclusions  These results suggest that polymorphisms of rs1801159 in DPYD may be used as valuable predictors of the response to fluorouracil-based chemotherapy for gastric cancer patients in the Chinese population. Well-designed, comprehensive, and prospective studies on determining these polymorphisms of DPYD as predictive markers for gastric cancer in response to fluorouracil-based therapies are warranted.

     

喉癌CD133+肿瘤干细胞与化疗抵抗

目的 筛选喉癌细胞中的CD133+细胞亚群,探讨其肿瘤干细胞特性及化疗抵抗性,并分析其原因。 方法 流式细胞仪检测Hep-2细胞经顺铂,氟尿嘧啶,紫杉醇作用后,CD133表达率的变化。采用流式细胞分选技术分离CD133+,CD133-细胞亚群,观察各亚群对上述药物的反应。采用软琼脂克隆形成实验检测各亚群的克隆形成能力,采用transwell小室体外侵袭实验,检测各亚群细胞的侵袭能力。采用逆转录聚合酶链反应(RT-PCR)和western blot法,检测各亚群细胞中耐药基因ABCG2基因的表达。 结果：Hep-2细胞中CD133表达率为1-2%. 化疗药物作用后CD133+亚群被富集。CD133+细胞克隆形成率为(41.9±3.9%)显著高于CD133-细胞(11.7±1.6%), P<0.01。CDl33+细胞侵袭细胞数为(88±9.7)显著高于CD133-细胞（53±7.2）, P<0.01。CD133+细胞ABCG2的表达水平显著高于CD133-细胞。 结论： CDl33+喉癌细胞具有肿瘤干细胞的生物学特性, CD133+喉癌肿瘤干细胞存在化疗抵抗,ABCG2的高表达是其中的主要原因。针对CD133+细胞的治疗势必会促进对喉癌治疗的进展。     

桑辛素对喉癌干细胞干性表型调控的作用研究

  目的  探索桑辛素对喉癌干细胞干性表型调控的影响。  方法  流式细胞仪分选并检测CD133+喉癌干细胞比例;肿瘤球形成实验检测CD133+喉癌干细胞的自我更新能力;Transwell实验检测CD133+喉癌干细胞的迁移能力;改良MTT实验检测化疗药物对CD133+喉癌干细胞的细胞毒性作用;免疫荧光染色、实时荧光定量PCR（RT-qPCR）及Western blot检测CD133+喉癌干细胞的干细胞标志物表达;在不同浓度的桑辛素处理CD133+喉癌干细胞后（以桑辛素0 μmol/L为对照）,通过肿瘤球形成实验、Transwell实验、改良MTT实验及Western blot,分别检测CD133+喉癌干细胞的自我更新能力、迁移能力、化疗药物的细胞毒性作用及干细胞标志物表达变化。  结果  流式细胞仪分选结果显示,CD133+喉癌干细胞占喉癌细胞的比例为（3.50±0.34）%;经过培养富集后,其比例可达（93.20±5.23）%。肿瘤球形成实验结果显示,与喉癌细胞相比,CD133+喉癌干细胞具有增强的自我更新能力 (P<0.001);Transwell实验显示,与喉癌细胞相比,CD133+喉癌干细胞的迁移能力增强（P<0.05）;改良MTT实验结果显示,与喉癌细胞相比,CD133+喉癌干细胞抵抗化疗药物（5-氟尿嘧啶及顺铂）的细胞毒性作用（P<0.05）;免疫荧光染色、RT-qPCR及Western blot结果显示,干细胞标志物（CD133、ALDH1、Sox2、ABCG2及N-cadherin）在CD133+喉癌干细胞中呈高表达水平。通过不同浓度的桑辛素处理CD133+喉癌干细胞,其自我更新能力降低（P<0.05）;迁移能力亦下降（P<0.05）;此外,桑辛素处理的CD133+喉癌干细胞对化疗药物的细胞毒性作用更加敏感（P<0.05）;Western blot结果显示,不同浓度的桑辛素处理的CD133+喉癌干细胞,其上述的干细胞标志物表达水平下调（P<0.05）。  结论  CD133+喉癌干细胞具有干性表型特征;桑辛素可减弱喉癌干细胞的干性表型,可能与下调其干细胞标志物表达相关。     

喉癌干细胞的培养及其放射抗拒相关miRNA的筛选研究

目的通过培养Hep-2喉癌细胞株,分离并扩增出肿瘤干细胞,放疗后筛选出调控放射抗拒的miRNA。方法含生长因子的无血清培养基培养Hep-2喉癌细胞株,流式细胞仪检测细胞中侧群细胞的比例。当侧群细胞比例达25%时,收集全部细胞球,筛选出CD133+、CD44+细胞作为喉癌干细胞,X线照射喉癌干细胞。miRNA生物芯片检测照射与未照射的喉癌干细胞,筛选出喉癌干细胞中2倍差异表达的miRNA,确定用以调控放射抗拒的miRNA。结果成功培养出侧群细胞,流式细胞仪检测其比例达到26.2%,筛选出的CD133+、CD44+细胞的比例均高于91%。通过miRNA芯片成功检测出喉癌干细胞中2倍差异表达的miRNA。结论本研究成功培养出喉癌干细胞,成功筛选出喉癌干细胞中2倍差异表达的miRNA,发现了可能用以调控放射抗拒的miRNA。     

小细胞肺癌细胞系H446中肿瘤干细胞的分选与鉴定

 目的 明确能否以表面黏附分子CD133为干细胞标志物,使用免疫磁珠分选（magnetic cell separation,MACS）法分离小细胞肺癌细胞系H446细胞中的肿瘤干细胞。方法 以CD133为特异性分子标志物,使用MACS方法分选H446细胞,比较CD133阳性（CD133+）细胞与CD133阴性（CD133-）细胞在集落形成、自我更新、增殖分化、侵袭性、耐药性和成瘤性方面的不同。结果 CD133+细胞和CD133-细胞在集落形成能力、自我更新能力、增殖能力、分化能力、侵袭能力和耐药性方面基本相同。集落形成和成瘤性实验结果显示：CD133+或CD133-细胞中40%以上的细胞都能够形成含有100个细胞以上的大集落,增殖成为与未分选细胞相同的细胞群,并能在裸鼠身上成瘤。结论 表面黏附分子CD133不能作为分选小细胞肺癌H446细胞系中肿瘤干细胞的分子标志物,分选后的CD133+与CD133-细胞中含有相同的肿瘤干细胞。     

miRNA-29c在喉癌组织中的表达及对喉癌Hep-2细胞增殖、侵袭的影响

目的 观察miRNA-29c 在喉癌组织和喉癌Hep-2 细胞株中的表达情况,研究其与肿瘤临床分期、淋巴转移及预后等临床病理参数的关系,并探讨miRNA-29c 对喉癌Hep-2 细胞增殖、侵袭的影响。 方法 选取2006 年1 月～2016 年12 月在我院确诊的86 例喉癌患者的蜡块标本,利用实时荧光定量聚合酶链式反应检测喉癌组织和癌旁正常喉黏膜上皮组织中miRNA-29c 的表达,并分析其与临床病理学特征的关系;通过Q-RT-PCR 检测转染后每组细胞中miRNA-29c 的表达;CCK-8 检测细胞增殖能力变化情况;Transwell 实验检测跨膜细胞数量的变化。 结果miRNA-29c 在喉癌组织中相对表达量明显低于癌旁组织（P<0.01）,其表达量与不同临床分型、TNM分期、淋巴转移密切相关（P<0.05）;转染miRNA-29c 模拟物组细胞中的miRNA-29c 表达水平显著高于无关序列组和空白对照组（P<0.01）,并可抑制喉癌Hep-2 细胞的增殖和侵袭力（P<0.01）。 结论 在喉癌中,miRNA-29c 是一个抑制性miRNA,miRNA-29c 低表达可能是影响喉癌预后的重要因素;过表达miRNA-29c 可显著降低喉癌Hep-2 细胞的增殖和侵袭能力,miRNA 表达水平的下调可能参与了喉癌的发生发展及侵袭转移过程。     

分割剂量射线照射富集宫颈癌肿瘤干细胞的研究

【目的】 研究分割剂量射线照射的宫颈癌Hela细胞表达肿瘤干细胞相关蛋白情况及裸鼠体内成瘤能力,探讨经此法富集宫颈癌肿瘤干细胞的可行性。【方法】 Hela细胞分组接受分割剂量分别为2、4、6、8、10及12 Gy的射线照射,总照射剂量24 ~ 42 Gy。流式细胞术检测各照射组及对照组细胞的ABCG2、CD44及CD133表达率;各组细胞接种裸鼠皮下,检测其体内成瘤能力。【结果】 各照射组细胞的ABCG2表达率均明显上调,以Hela-R2组(4 Gy×10次)细胞的表达率最高[(46.89±1.20)%],且随着照射次数的增加而升高(P < 0.05);各组细胞的CD44及CD133表达率变化均无明显趋势;Hela-R2组细胞的裸鼠体内成瘤能力最高,其次为Hela-R5组(10 Gy×3次)。【结论】 分割剂量射线照射可在体外富集宫颈癌肿瘤干细胞,以分割剂量为4 Gy组富集效果最好,诱导Hela细胞株表达ABCG2显著上调,及提高其裸鼠体内成瘤能力。     

人卵巢肿瘤细胞系3AO中肿瘤干细胞的分离鉴定

目的利用CD133抗体偶联的免疫磁珠分选法从人卵巢肿瘤3AO细胞系中分离CD133+细胞,并且通过检测其抗凋亡能力和耐药性进一步鉴定其特征。方法通过免疫磁珠分选方法分离人卵巢肿瘤细胞系中CD133+肿瘤干细胞,流式细胞仪检测肿瘤干细胞自我更新能力和抗凋亡能力,裸鼠移植实验反映成瘤性,MTT法检测其耐药性。结果通过免疫磁珠手段可成功分离得到CD133+卵巢肿瘤肿瘤干细胞,细胞增殖活力好,自我更新能力强,随着培养时间的延长可产生大量的CD133-细胞。裸鼠移植成瘤实验表明CD133+细胞成瘤率是10/10,成瘤平均时间是(58±6)d;而CD133-成瘤率是4/10,平均成瘤时间是(145±8)d,CD133+细胞成瘤能力明显强于CD133-细胞。MTT检测结果表明CD133+细胞的IC50值为CD133-细胞的2.5倍左右,提示对顺铂药物不敏感。对使用顺铂的细胞进行吖啶橙染色后发现,大量CD133-细胞呈现细胞凋亡状态,而CD133+细胞形态基本正常。进一步的AnnexinⅤ-FITC和PI双染结果表明,药物处理后的CD133+细胞比CD133-细胞具有更强的抗凋亡能力。结论免疫磁珠分选得到的CD133+细胞具有自我更新、增殖和分化为CD133-细胞等肿瘤干细胞的特征。CD133+细胞比CD133-细胞具有较强的成瘤能力、耐药性及抗凋亡能力。     

HepG2、Hep3B细胞中肿瘤干细胞相关标志分子的表达

目的富集培养肝癌干细胞,研究肝癌干细胞相关标志物CD90、CD133、八聚体4(Oct4)和ATP结合盒转运蛋白ABCG2在肝癌细胞HepG2、Hep3B中的表达,并初步分析其意义。方法使用流式细胞仪从肝癌细胞(检测HepG2、Hep3B两种细胞系)中分选肝癌干细胞并行无血清成球培养。设肝癌细胞组为对照组。单细胞克隆形成实验检测细胞增殖能力。分别给予肝癌细胞及肝癌干细胞阿霉素处理,MTT法测阿霉素处理后各组细胞的存活率,Real-time PCR及Western blot分别检测各组细胞CD90、CD133、Oct4和ABCG2 mRNA及蛋白水平的表达。结果肝癌干细胞单个细胞增殖能力强于肝癌细胞,克隆形成分析显示培养第14天克隆形成率Hep3B细胞组低于Hep3B CSCs组[8/27(30%)vs 12/23(52%),P<0.05];HepG2细胞组克隆形成率也低于HepG2 CSCs组[7/38(18%)vs 9/26(35%),P<0.05]。用阿霉素处理肝癌细胞及肝癌干细胞48 h后,MTT法测定结果显示肝癌干细胞组细胞活性显著高于对照组(P<0.05):HepG2细胞组细胞活性为(38.17±6.92)%、HepG2 CSCs组为(69.88±5.43)%;Hep3B细胞组(50.16±4.89)%,Hep3B CSCs组为(78.53±7.86)%。Real-time PCR结果显示肝癌干细胞组中CD90、CD133、Oct4及ABCG2基因mRNA表达较亲代细胞组显著上调(P<0.05)。Western blot结果显示肝癌干细胞组Oct4及ABCG2蛋白水平显著上调,与亲代细胞组间表达差异有显著性(P<0.05)。结论肝癌干细胞相关标志CD90、CD133、Oct4及ABCG2均高表达于肝癌干细胞,并且Oct4及ABCG2基因的高表达有可能与肝癌干细胞耐药性相关。     

Influence of CD133~+ expression on patients' survival and resistance of CD133~+ cells to anti-tumor reagents in gastric cancer

Objective:To investigate the influence of CD133+expression on patients'survival and resistance of CD133+cells to anti-tumor agents in gastric cancer(GC).Methods:Influence of CD133 expression on prognosis was analyzed employing samples from patients with GC.GC cell lines were utilized to separate CD133+and CD133-subpopulations by immunomagnetic separation and to analyze the biological features of two subpopulations in vitro and in vivo,especially in resistant to anti-tumor reagents and its apoptotic mechanism.Results:The lower CD133+group showed a significantly better survival compared with the higher CD133+group.The highest content of CD133+subpopulations for KATO-III cells had stronger proliferative ability than CD133-subpopulations.A single CD133+cell was capable of generating new cell colony and the tumorigenicity rate in nude mice was100%for CD133+clonal spheres or for CD133+cells,but 0%for CD133-cells.Furthermore,the higher expression levels of Oct-4,Sox-2,Musashi-1 and ABCG2 in CD133+clonal spheres were identified compared with CD133+cells or CD133-cells.Under the treatment of anti-tumor reagents,CD133+cells had lower suppression rates compared with CD133-cells while lower level of Bcl-2 and higher level of Bax were found in CD133+cells compared with CD133-cells.Conclusions:The patients with lower CD133+expression had a better survival.Enriched CD133+cells in clonal sphere shared the ability to be self-renewable,proliferative,tumorigenic and resistant to anti-tumor agents as probably regulated by Bcl-2 and Bax.     

Rac1+ cells distributed in accordance with CD 133+ cells in glioblastomas and the elevated invasiveness of CD 133+ glioma cells with higher Rac1 activity

Background  Recent studies have suggested that cancer stem cells are one of the major causes for tumor recurrence due to their resistance to radiotherapy and chemotherapy. Although the highly invasive nature of glioblastoma (GBM) cells is also implicated in the failure of current therapies, it is not clear how glioma stem cells (GSCs) are involved in invasiveness. Rac1 activity is necessary for inducing reorganization of actin cytoskeleton and cell movement. In this study, we aimed to investigate the distribution characteristics of CD133+ cells and Rac1+ cells in GBM as well as Rac1 activity in CD133+ GBM cells, and analyze the migration and invasion potential of these cells.

Methods  A series of 21 patients with GBM were admitted consecutively and received tumor resection in Tianjin Medical University General Hospital during the first half of the year 2011. Tissue specimens were collected both from the peripheral and the central parts for each tumor under magnetic resonance imaging (MRI) navigation guidance. Immunohistochemical staining was used to detect the CD133+ cells and Rac1+ cells distribution in GBM specimens. Double-labeling immunofluorescence was further used to analyze CD133 and Rac1 co-expression and the relationship between CD133+ cells distribution and Rac1 expression. Serum-free medium culture and magnetic sorting were used to isolate CD133+ cells from U87 cell line. Rac1 activation assay was conducted to assess the activation of Rac1 in CD133+ and CD133- U87 cells. The migration and invasive ability of CD133+ and CD133- U87 cells were determined by cell migration and invasion assays in vitro. Student’s t-test and one-way analysis of variance (ANOVA) test were used to determine statistical significance in this study.

Results  In the central parts of GBMs, CD133+ cells were found to cluster around necrosis and occasionally cluster around the vessels under the microscope by immunohistological staining. In the peripheral parts of the tumors, CD133+ cells were lined up along the basement membrane of the vessels and myelinated nerve fibers. Rac1 expression was high and diffused in the central parts of the GBMs, and the Rac1+ cells were distributed basically in accordance with CD133+ cells both in the central and peripheral parts of GBMs. In double-labeling immunofluorescence, Rac1 was expressed in (83.14±4.23)% of CD133+ cells, and CD133 and Rac1 co-expressed cells were located around the vessels in GBMs. Significantly higher amounts of Rac1-GTP were expressed in the CD133+ cells (0.378±0.007), compared to CD133- cells (0.195±0.004) (t=27.81; P <0.05). CD133+ cells had stronger ability to migrate (74.34±2.40 vs. 38.72±2.60, t=42.71, P <0.005) and invade (52.00±2.28 vs. 31.26±1.82, t=30.76, P <0.005), compared to their counterpart CD133- cells in transwell cell migration/invasion assay.

Conclusions  These data suggest that CD133+ GBM cells highly express Rac1 and have greater potential to migrate and invade through activated Rac1-GTP. The accordance of distribution between Rac1+ cells and CD133+ cells in GBMs implies that Rac1 might be an inhibited target to prevent invasion and migration and to avoid malignant glioma recurrence.