Inhibition of PIM Kinases Promotes Neuroblastoma Cell Differentiation to a Neuronal Phenotype

BackgroundNeuroblastoma arises from aberrancies in neural stem cell differentiation. PIM kinases contribute to cancer formation, but their precise role in neuroblastoma tumorigenesis is poorly understood. In the current study, we evaluated the effects of PIM kinase inhibition on neuroblastoma differentiation.MethodsVersteeg database query assessed the correlation between PIM gene expression and the expression of neuronal stemness markers and relapse free survival. PIM kinases were inhibited with AZD1208. Viability, proliferation, motility were measured in established neuroblastoma cells lines and high-risk neuroblastoma patient-derived xenografts (PDXs). qPCR and flow cytometry detected changes in neuronal stemness marker expression after AZD1208 treatment.ResultsDatabase query showed increased levels of PIM1, PIM2, or PIM3 gene expression were associated with higher risk of recurrent or progressive neuroblastoma. Increased levels of PIM1 were associated with lower relapse free survival rates. Higher levels of PIM1 correlated with lower levels of neuronal stemness markers OCT4, NANOG, and SOX2. Treatment with AZD1208 resulted in increased expression of neuronal stemness markers.ConclusionsInhibition of PIM kinases differentiated neuroblastoma cancer cells toward a neuronal phenotype. Differentiation is a key component of preventing neuroblastoma relapse or recurrence and PIM kinase inhibition provides a potential new therapeutic strategy for this disease.     

The Effects of Protein Phosphatase 2A Activation with Novel Tricyclic Sulfonamides on Hepatoblastoma

BackgroundThe tumor suppressor, protein phosphatase 2A (PP2A), is downregulated in hepatoblastoma. We aimed to examine the effects of two novel compounds of the tricyclic sulfonamide class, ATUX-3364 (3364) and ATUX-8385 (8385), designed to activate PP2A without causing immunosuppression, on human hepatoblastoma.MethodsAn established human hepatoblastoma cell line, HuH6, and a human hepatoblastoma patient-derived xenograft, COA67, were treated with increasing doses of 3364 or 8385, and viability, proliferation, cell cycle and motility were investigated. Cancer cell stemness was evaluated by real-time PCR and tumorsphere forming ability. Effects on tumor growth were examined using a murine model.ResultsTreatment with 3364 or 8385 significantly decreased viability, proliferation, cell cycle progression and motility in HuH6 and COA67 cells. Both compounds significantly decreased stemness as demonstrated by decreased abundance of OCT4, NANOG, and SOX2 mRNA. The ability of COA67 to form tumorspheres, another sign of cancer cell stemness, was significantly diminished by 3364 and 8385. Treatment with 3364 resulted in decreased tumor growth in vivo.ConclusionNovel PP2A activators, 3364 and 8385, decreased hepatoblastoma proliferation, viability, and cancer cell stemness in vitro. Animals treated with 3364 had decreased tumor growth. These data provide evidence for further investigation of PP2A activating compounds as hepatoblastoma therapeutics.     

PIM447 inhibits oncogenesis and potentiates cisplatin effects in hepatoblastoma

Background: Novel therapies are needed for patients with hepatoblastoma because of an increasing incidence of disease and poor prognosis for advanced, refractory, and recurrent disease. PIM kinases promote tumorigenesis in hepatoblastoma. A novel PIM inhibitor, PIM447, has shown promise in inhibiting oncogenesis in hematologic and lymphoid malignancies. We hypothesized that PIM inhibition with PIM447 would result in decreased tumorigenesis in hepatoblastoma.Methods: The effects of PIM447 on hepatoblastoma viability, proliferation, motility, apoptosis, and tumor cell stemness were assessed in HuH6, a human hepatoblastoma cell line, and COA67, a human hepatoblastoma patient-derived xenograft.Results: PIM447 significantly decreased the viability, proliferation, and motility of HuH6 and COA67 cells. Apoptosis significantly increased following PIM447 treatment. PIM447 had a significant impact on tumor cell stemness as evidenced by decreased expression of CD133 and reduced ability of HuH6 and COA67 cells to form tumorspheres. Furthermore, combining PIM447 with cisplatin resulted in a significant decrease in cell viability compared to either treatment alone.Conclusion: We showed that PIM447 inhibits oncogenesis and potentiates the effects of cisplatin in hepatoblastoma and, therefore, warrants further investigation as a potential therapeutic agent for hepatoblastoma.     

Corruption of neuroblastoma patient derived xenografts with human T cell lymphoma

BackgroundPatient derived xenografts (PDXs) provide a unique opportunity for investigators to study tumor cell activity, response to therapeutics, and resistance patterns without exposing the human patient to experimental compounds, and thereby play a crucial role in pre-clinical evaluation of new therapies. It has been reported that PDXs may undergo a transformation to lymphoma, most commonly associated with Epstein Barr virus (EBV). If the character of a xenograft becomes compromised and remains undetected, it could have a detrimental impact on the research community as a whole. Our lab has established a number of pediatric solid tumor PDXs which accurately recapitulate the human tumors following several passages. One particular neuroblastoma PDX was noted to grow quickly and with an unusual phenotype, leading us to hypothesize that this PDX had undergone a transformation.MethodsThe PDX in question was investigated with histology, immunohistochemistry (IHC), EBER in situ hybridization, and PCR to determine its identity.ResultsHistology on the tumor revealed a small, round blue cell tumor similar to the original neuroblastoma from which it was derived. IHC staining showed that the tumor was composed of lymphocytes that were CD3 positive, < 5% CD4 positive, and CD20 negative. The cells were Epstein Barr virus negative. PCR demonstrated that the tumor was human and not murine in origin.ConclusionThese findings indicate that a human T Cell lymphoma developed in place of this neuroblastoma PDX. Changes in PDX identity such as this one will significantly impact studies utilizing pediatric PDXs and the mechanism by which this occurred warrants further investigation.     

Mammospheres of hormonal receptor positive breast cancer diverge to triple-negative phenotype

ObjectivesThis study aimed to characterize mammospheres from hormonal receptor (HR) positive and triple-negative breast cancer (TNBC), hypothesizing a differential profile of CSC and differentiation markers, and a stemness enrichment when successive sphere forming-protocols are performed.MethodsBreast cancer cells MCF-7 and HCC1806 were submitted to sphere-forming protocols. The first sphere generation (MS1) was cultured in adherent conditions (G1). This procedure was repeated and generations of mammospheres (MS1, MS2, and MS3) and sphere-derived cells in adherent conditions (G1, G2, and G3) were obtained. The mammosphere forming capacity, self-renewal, area and doubling time were evaluated. Flow cytometry regarding CD133, CD24, and CD44 and western-blot regarding aldehyde dehydrogenase (ALDH), hormonal receptors and P53 expression was performed.ResultsBreast cancer cell lines harboured the capacity to form spheres, which originated derived adherent populations. The sphere-forming capacity was enhanced in HCC1806-MS3 compared to MS1. Self-renewal was higher in MCF-7 mammospheres, which also had an increased area. The putative CSC markers CD133 showed tendency to be enhanced in mammospheres but the CD44⁺/CD24^-/low phenotype was not identified. The expression of ALDH was greater in mammospheres from MCF-7 and HCC1806 than in the respectively derived adherent cells. The expression of oestrogen receptor (ER)-α, progesterone receptor (PR) and P53 decreased in MCF-7 spheres. ER-β expression was lower in mammospheres from both cell lines compared with parental and derived adherent populations.ConclusionsLoss of HR and P53 expression in HR-positive mammospheres evidences the minor population of CSC which shares characteristics with the TNBC phenotype.     

Chemoresistance to 5-FU inhibited by 635 nm LED irradiation in CD133+ KB cell line

Consistent with cancer stem cell theory, a small fraction of cancer cells, described as cancer stem cells (CSCs), may promote tumor recurrence and anti-cancer drug resistance. Therefore, much effort has been devoted to the development of CSC targeted therapy to vanquish drug resistance. In this study, we have investigated the effect of multiple light-emitting diode (LED) irradiation treatments with conventional anti-cancer drugs on CSC-like oral cancer cells that acquired stemness by ectopic over expression of CD133. To evaluate combined LED irradiation anti-cancer drug effects, we investigated the chemosensitizing effect of 635 nm irradiation on 5-fluorouracil (5FU)-treated KB^CD133+ and KB^Vec cells, interrogating the underlying molecular mechanisms associated with stemness and apoptosis that are responsible for chemopreventive activity. In addition, combination therapy with LED irradiation and 5-FU treatment was carried out in KB^CD133+ and KB^Vec cell-inoculated mouse models. LED irradiation of 635 nm inhibited CSC-like properties consistent with a decrease in OCT4 and NANOG protein expression, reducing colony-forming ability. In addition, LED irradiation enhanced 5-FU-induced cytotoxicity and improved 5-FU chemosensitivity in KB^CD133+ via enhancement of apoptosis. These findings were validated in vivo, wherein LED irradiation combined with 5-FU treatment inhibited tumor growth in KB^CD133+-inoculated mice. Collectively, our results provide novel evidence for 635 nm irradiation-induced 5-FU chemosensitization of CSC in oral cancer. In addition, this research highlights that 635 nm LED irradiation may serve as an adjunct treatment to conventional chemotherapeutic drugs in patients with oral cancer.     

Salinomycin Selectively Targets ‘CD133+’ Cell Subpopulations and Decreases Malignant Traits in Colorectal Cancer Lines

Background

Cancer stem-like cells (CSCs) in colorectal cancers (CRC) may account for the failure of treatments because they are resistant to many current anticancer therapies. Salinomycin, a potassium ionophore, was recently identified as a selective inhibitor of breast CSCs.

Methods

The human CRC cell lines HT29 and SW480 were treated with salinomycin and oxaliplatin. Cell viability was determined with cell counting kit 8. Fraction of CD133+ cell subpopulations was assessed by Flow Cytometric analysis. Clonogenecity and migration were determined with soft agar and Boyden chamber assays. Molecular changes were assessed by immunofluorescence staining, RT-PCR, and Western blot analysis.

Results

We report that salinomycin reduces the proportion of CD133+ subpopulations in human CRC HT29 and SW480 cells. Furthermore, salinomycin treatment decreases colony-forming ability and cell motility in HT29 cells. Moreover, salinomycin downregulates the expression of vimentin and induces the E-cadherin expression in HT29 cells.

Conclusions

This study demonstrates the ability of salinomycin to selectively target “CD133+” cell subpopulations and decrease the malignant traits in colorectal cancer lines.     

RNA干扰抑制CD44和CD133的表达对肺腺癌A549细胞增殖能力的影响

目的 观察CD44和CD133的表达对人肺腺癌A549细胞株增殖能力的影响.方法 筛选可持续增殖的A549细胞并培养,按CD44和133表达的不同将筛选出的细胞分成5组,非转染组:CD44+CD133+细胞(A组)、CD44-/CD133-细胞(B组)、未分选A549细胞(C组);转染组:CD44-和CD133-细胞(D组)及阴性对照组(E组).筛选得到沉默效果最佳的小干扰RNA(siRNA)片段,并用其转染各组细胞,采用MTS法检测并比较干扰前后各组细胞的增殖能力.结果　沉默效果最佳的siRNA片段及浓度为siCD44-h_002 25 nmol/L和siCD133-h_002 25 nmol/L,沉默效率分别为62%和82%.用其转染各组样本后,CD44和CD133的表达明显被抑制,比较转染前后各组样本的灰度值,差异有统计学意义(P＜0.01).通过分析MTS图显示,转染后细胞的增殖能力显著下降.结论　CD44和CD133的阳性表达,与人肺腺癌A549细胞株较强的增殖能力有关,CD44和CD133可能是肺腺癌干细胞的表面标志物.

Abstract：

Objective To study the effect of expression of CD44 and CD133 on the tumorigenesis of human lung adenocarcinoma cell line A549. Methods A549 cells having continuous self-renewal ability were cultured, and classified into 5 subpopulations based on differential expression patterns for CD133and CD44. The small interfering RNA (siRNA) with optimal sequences was screened out, and transfected the A549 cells. The methods of MTS and cell counting were used to investigate the proliferation of A549cells before and after the expression of CD133 and CD44 was inhibited by RNAi. Results For the optimal sequences and concentrations for siRNA transfection efficiency being 25 nmol/L for both siCD44-h_002 25and siCD133-h_002 25, the transfection efficiency was 62% and 82% respectively. Stably transfected cells were screened, and the expression of CD44 and CD133 was inhibited significantly. The gray values before transfection were significantly different from those after transfection ( P ＜ 0. 01 ). The MTS curve showed that the cell viability was significantly decreased after transfection. Conclusion The proliferation ability of A549 cells was related to the positive expression of CD44 and CD133. CD133 and CD44 may be important surface markers of lung cancer stem cells.     

Biological and Genetic Characteristics of Tumor-Initiating Cells in Colon Cancer

Background Human prominin-1 (PROM1, CD133) was used as a marker to detect stem cells (progenitor cells) and cancer stem cells (tumor-initiating cells) in various tissues. The purpose of this study was to investigate the biological and genetic characteristics of tumor-initiating cells in colon cancer with both in vitro and in vivo analyses. Methods The CD133 expression of 12 colon cancer cell lines was evaluated. CD133⁺ cells were isolated by flow cytometry and examined for in vivo tumor formation, in vitro proliferation, colony formation, and invasion ability. Additionally, we used microarray analysis to compare gene expression profiles between CD133⁺ and CD133^– isolated cells. Results CD133⁺ cells were found in 5 of 12 colon cancer cell lines. Isolated CD133⁺ cells from the HT29 colon cancer cell line exhibited a higher tumorigenic potential than CD133^– cells in the in vivo tumor formation assay. Furthermore, it was shown that CD133⁺ cells are more proliferative and have higher colony-forming and invasive abilities than CD133^– cells in vitro. Microarray analysis found differential gene expression correlating with CD133 expression. Conclusions It was confirmed that CD133⁺ cells in colon cancer are useful markers for the detection of tumor-initiating cells. Intimate biological and genetic features of CD133⁺ cells in colon cancer cell lines were also revealed. The biological characteristics of CD133⁺ cells and differentially expressed genes in these cells will help elucidate more details of tumor-initiating cells in colon cancer. Electronic supplementary material The online version of this article (doi: ) contains supplementary material, which is available to authorized users     

RNA干扰抑制KATO-Ⅲ CD133阳性胃癌细胞CD133基因表达及对其生物学特性的影响

目的 探讨CD133基因表达被抑制后对胃癌细胞增殖、侵袭、克隆球形成及化疗药物敏感性的影响.方法 通过免疫磁珠分选KATO-Ⅲ胃癌细胞中的CD133阳性细胞,将合成的CD133小干扰核糖核酸分子（siRNA）转染至KATO-ⅢCD133阳性胃癌细胞内,使用荧光标记的siRNA （FAM-siRNA）检测转染效率,通过RT-PCR、Western-blot方法检测CD133基因表达的沉默效果及上皮-间质转化（EMT）相关因子（E-cadherin、Snail和N-cadherin）的蛋白表达,采用CCK-8、Transwell侵袭实验、单克隆球形成实验和CCK- 8等方法分别检测细胞增殖、侵袭、克隆球形成能力及对化疗药物5-氟尿嘧啶（5-FU）的敏感性.结果 转染24 h后,转染效率可达到（87.7±8.1）％.干扰组CD133 mRNA及蛋白的表达显著低于阴性对照组（P＜0.01）.转染24、48和72 h后,与阴性对照组比较,干扰组细胞的增殖活性均得到显著抑制,差异均有统计学意义（P＜0.01）;转染72 h,干扰组细胞的增殖活性较阴性对照组降低了（52.1±8.0）％.与阴性对照组比较,干扰组的细胞侵袭数减少[（41.7±6.0）比 （130.3±11.0）,P＜0.05],克隆球形成率降低[（24.3±4.3）％比（45.1±6.4）％,P＜0.01],Snail和N- cadherin蛋白表达降低（P＜0.01）,而E-cadherin蛋白表达增高（P＜0.01）.干扰组细胞对化疗药物5-FU的敏感性显著增强,5-FU对干扰组细胞的抑制率为（62.4±3.3）％,较阴性对照组的（21.5±2.2）％增加（P＜0.01）.结论 CD133基因在胃癌细胞的增殖、侵袭、克隆球形成和化疗抵抗性等方面具有重要作用,可能是胃癌干细胞新型标志物,有望成为胃癌生物治疗的新靶点.     

Effective enrichment of prostate cancer stem cells from spheres in a suspension culture system

BackgroundStem-like prostate cancer cells are also called prostate cancer stem cells (PrCSCs). These rare cells are supposed to be highly tumorigenic and to be involved in maintenance of tumor homeostasis and mediation of tumor metastasis. Methods for sorting PrCSCs are mainly based on sorting cells with the marker (CD133⁺/CD44⁺) or side population cells. However, CD133⁺/CD44⁺ cells or side population cells are very rare or even undetectable. The scarcity of approaches for isolation and purification of PrCSCs is the main obstacle to studying PrCSCs.MethodsIn the present study, suspension culture was used for enrichment of PrCSCs. And PrCSCs were verified by side population technology, drug sensitivity assays, and the molecular marker analysis of prostate cancer stem cell.ResultsPC3 cells survived and formed spheres in nonadherent suspension culture. The percentage of CD44⁺/CD133⁺ cells was 18-fold higher in the nonadherent sphere-forming cell population than in the adherent PC3 cell population (13.94% vs. 0.77%, respectively). This side population was increased to 3.1% in the nonadherent population but undetectable in adherent population. Resistance to cisplatin was higher in the nonadherent cells than adherent cells.ConclusionSuspension culture can be used to enrich for PrCSCs. This approach will aid prostate stem cell biology research and facilitate identification of novel therapeutic agents for prostate cancer.     

Benzodiazepines safeguards nerve cells from the toxicity of lidocaine via miR-133a-3p/EGFR pathway

BackgroundLidocaine was an anesthetic commonly used for analgesia, but the neurotoxicity could not be ignored. However, benzodiazepines could alleviate the toxicity when combined with other drugs.PurposeTo explore the molecular mechanism of benzodiazepines in protecting nerve cells after the induction of lidocaine.MethodsPC12 cells were induced by lidocaine (0 mM, 0.1 mM, 0.5 mM and 1 mM) first and then treated by benzodiazepines (0 μM–200 μM). RT-qPCR assays measured RNA expressions of epidermal growth factor receptor (EGFR) and microRNA-133a-3p (miR-133a-3p) in PC12 cell line, respectively. Western blot was for protein detections of EGFR and caspase-3. Flow cytometry assay assessed apoptosis and cellular viability was validated via Cell Counting Kit-8 (CCK-8) test. Bioinformatics analysis predicted the potential link between miR-133a-3p and EGFR and the binding was verified using the Dual luciferase reporter experiment.ResultsBenzodiazepines increased cellular viability of PC12 cells up to 100 μM while suppressed viability between 100 and 200 μM. Benzodiazepines (0 μM, 10 μM, 50 μM and 100 μM) did not regulate PC12 cell viability but promoted the viability of lidocaine-treated PC12 cells. Lidocaine downregulated miR-133a-3p RNA expression but facilitated EGFR mRNA expression, which was reversed after treated by benzodiazepines. MiR-133a-3p targeted and negatively regulated EGFR expressions in mRNA and protein levels. Furthermore, miR-133a-3p inhibitor and overexpressed EGFR transfection both restrained the decreased PC12 cell viability and prompted cell apoptosis caused by benzodiazepines.ConclusionBenzodiazepines restrained lidocaine-induced toxicity in PC12 cells which secured viability and reduced apoptosis via miR-133a-3p/EGFR pathway.     

MiR-133a induces apoptosis through direct regulation of GSTP1 in bladder cancer cell lines

ObjectiveWe previously demonstrated that miR-133a is a tumor-suppressive microRNA (miRNA) and is commonly down-regulated in human bladder cancer (BC). The aim of this study is to determine a novel oncogenic gene targeted by miR-133a in BC.MethodsTo identify genes targeted by miR-133a, an oligo-microarray analysis was performed using the miR-133a-transfected BC cell lines. For gain/loss-of-function studies, miR-133a/si-glutathione S-transferase π1 (GSTP1)-transfectants were subjected to XTT assay and flow cytometry to evaluate their cell viability and apoptosis status. The luciferase reporter assay was used to confirm the actual binding sites between miR-133a and GSTP1 mRNA. The mRNA and protein expression of GSTP1 in BC cell lines and clinical samples were evaluated by real-time RT-PCR and Western blot, respectively.ResultsMiR-133a transfection induced cell viability inhibition and apoptosis in BC cell lines. We focused on the GSTP1 gene that was the top 7 down-regulated one in the gene profile from the miR-133a-transfectants. MiR-133a transfection repressed expression levels of mRNA and protein levels of GSTP1. A luciferase reporter assay suggested that the actual binding may occur between miR-133a and GSTP1 mRNA. Cell viability inhibition and apoptosis were induced in the si-GSTP1 transfectants compared with the controls (P < 0.005). GSTP1 mRNA expression levels in 43 clinical BCs were significantly higher than those in eight normal bladder epitheliums (P = 0.0277).ConclusionOur data suggest that tumor suppressive miR-133a directly regulated oncogenic GSTP1 gene in BC, and that an anti-apoptotic effect mediated by GSTP1 is maintained by miR-133a down-regulation in human BC.     

PKI-587 and sorafenib alone and in combination on inhibition of liver cancer stem cell proliferation

Background

Deregulated Ras/Raf/mitogen-activated protein kinase and PI3 K/AKT/mTOR signaling pathways are significant in hepatocellular carcinoma proliferation (HCC). In this study we evaluated differences in the antiproliferative effect of dual PI3 K/Akt/mTOR and Ras/Raf/mitogen-activated protein kinase inhibition of non liver cancer stem cell lines (PLC and HuH7) and liver cancer stem cell (LCSC) lines (CD133, CD44, CD24, and aldehyde dehydrogenase 1-positive cells).

Materials and methods

Flow cytometry was performed on the resulting tumors to identify the LCSC markers CD133, CD44, CD24, and aldehyde dehydrogenase 1. Methylthiazol tetrazolium assay was used to assess cellular proliferation. Finally, a Western blot assay was used to evaluate for inhibition of specific enzymes in these two signaling pathways.

Results

Using flow cytometry, we found that LCSC contain 64.4% CD133 + cells, 83.2% CD44 + cells, and 96.4% CD24 + cells. PKI-587 and sorafenib caused inhibiton of LCSC and HCC cell proliferation. PLC cells were more sensitive to PKI-587 than LCSC or Huh7 (P < 0.001). Interestingly, HuH7 cells were more sensitive to sorafenib than LCSC or PLC cells. Additionally, combination therapy with PKI-587 and sorafenib caused significantly more inhibition than monotherapy in HuH7, PLC, and LCSC. Using the methylthiazol tetrazolium assay, we found that the LCSC proliferation was inhibited with sorafenib monotherapy 39% at 5 μM (P < 0.001; n = 12) and 67% by PKI-587 at 0.1 μM (P = 0.002, n = 12) compared with control. The combination of PKI-587 and sorafenib, however, synergistically inhibited LCSC proliferation by 86% (P = 0.002; n = 12).

Conclusions

LCSC (CD133+, CD44+, CD24+) were able to develop very aggressive tumors with low cell concentrations at 4 to 6 wk. Cells CD133+, CD44+, CD24+, which demonstrated at least moderate resistance to therapy in vitro. The combination of PKI-587 and sorafenib was better than either drug alone at inhibiting of LCSC and on HCC cell proliferation.     

VS-5584, a PI3K/mTOR dual inhibitor,exerts antitumor effects on neuroblastomas in vitro and in vivo

BackgroundThe phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway is closely related to oncogenesis. PI3K/mTOR inhibitors are considered capable of counteracting the feedback mechanisms within the pathway. In this study, we investigated the antitumor effects of VS-5584, an orally administered PI3K/mTOR dual inhibitor, on neuroblastomas.MethodsThe effects of VS-5584 on proliferation, cell cycle distribution, and related signaling molecules were examined in neuroblastoma cells using the (3-[4,5-dimethylthiazole-2-yl]-2,5-diphenyltetrazolium bromide)-based colorimetric assay, flow cytometry, and western blotting, respectively. Nude mice were subcutaneously inoculated with human neuroblastoma cells, followed by VS-5584 treatment for two weeks. Tumor growth was tracked and tumor tissues were subjected to immunohistochemical investigations.ResultsIn neuroblastoma cells, VS-5584 significantly inhibited proliferation and induced G0/G1 cell cycle arrest. Additionally, VS-5584 decreased the expression of phospho-S6 kinase 1 (p-S6K1), p-retinoblastoma protein, p-cyclin-dependent kinase 2, and cyclin E1, and increased the expression of p21 and p27 in neuroblastoma cells. In mice, VS-5584 significantly suppressed tumor growth in neuroblastomas and downregulated the expression of p-mTOR and p-S6K1 in tumor tissues.ConclusionsVS-5584 blocks the PI3K/mTOR pathway, induces a G0/G1 cell cycle arrest, and exerts antitumor effects on neuroblastomas both in vitro and in vivo.     

肾癌中CD133＋细胞和CD133-细胞生物学特性差异的研究

目的：研究人肾癌细胞系786-O和OS-RC-2中CD133＋细胞和CD133-细胞的生物学特性差异。方法：应用流式细胞仪检测肾癌细胞系786-O和OS-RC-2中CD133的膜表达状况;以免疫磁珠法将CD133＋细胞和CD133-细胞分离纯化,比较两者在光镜下的形态、生长特点、体外增殖能力、长期分化能力及体外克隆形成率的差异;流式细胞术分析两者细胞周期分布的变化,采用MTT法分析两者对化疗药物顺铂（DDP）（10、20、50、80／Lg／ml）敏感性的差别。结果：786-O和0S-RC-2均有CD133的少量表达,表达率为（8．12±0．86）％、（6．83±0．20）％,CD133＋细胞和CD133-细胞相比具有较强的体外增殖、克隆形成及长期分化能力;细胞耐药性实验表明CD133＋细胞、CD133-细胞对50bcg／m1DDP敏感性差异有统计学意义（P〈0．05）。结论：肾癌细胞系中CD133＋细胞具有肾癌干细胞的部分特征,能否作为肾癌干细胞的表面标志还需要进一步的实验加以明确。     

Photodynamic therapy with 5-aminolevulinic acid: A new diagnostic,therapeutic, and surgical aid for neuroblastoma

Background5-Aminolevulinic acid (ALA)-based photodynamic therapy (PDT) is widely used in cancer therapy because of the tumor-specific accumulation of photosensitizing protoporphyrin IX (PpIX). We aimed to assess the susceptibility of human neuroblastoma cell lines to ALA-PDT and determine the mechanism of PDT.MethodsWe used four human neuroblastoma cell lines (GOTO, NB9, IMR32, and NB1) and a gastric cancer cell line (MKN45) as a positive control. Cells were treated with increasing concentrations of ALA, and the ALA-induced production of PpIX in tumor cells was quantified using fluorescence spectrophotometry. PDT photocytotoxicity was measured by exposing the cells to a 630-nm irradiation for 10 min, and apoptotic cells stained with phosphatidylserine (PS) and propidium iodide (PI) were detected through flow cytometry.ResultsALA cytotoxicity was not observed in any cell line. The intracellular concentration of PpIX increased in an ALA dose-dependent manner, and intracellular fluorescence of PpIX increased in a time-dependent manner. The viability of NB-1 cells treated with 250 μM 5-ALA rapidly decreased to 5%. Photocytotoxicity was observed in the following order: NB1, IMR32, NB-9, and GOTO. Photocytotoxicity was positively correlated with intracellular PpIX concentrations. PS+/PI- cells increased up to 21% after 12 h, and PS+/PI+ cells accounted for 35% of all cells after 24 h, which suggests that ALA-PDT induced apoptotic cell death.ConclusionThis study shows that neuroblastoma cell lines were susceptible to 5-ALA-PDT, resulting in persistent apoptotic cell death.Levels of evidenceN/A for basic study.     

Difference between phenotypes of bone marrow and peripheral blood leukocytes indicate rheumatoid arthritis bone marrow as an important site for cell activation and proliferation

ObjectivesAlthough the pathogenesis of RA is still unknown, recent data suggest bone marrow compartment is an important site contributing to the initiation and perpetuation of chronic inflammation that may spread to the joint. The aim of the present study was to compare phenotypes of bone marrow and peripheral blood leukocytes isolated from rheumatoid arthritis (RA) and osteoarthritis (OA) patients that may indicate whether bone marrow is implicated in the activation and propagation of mature leukocytes.MethodsMononuclear cells were isolated from peripheral blood and bone marrow of patients with RA and OA undergoing hip replacement. Sodium citrate was used as an anticoagulant. To assess cell phenotypes, specific monoclonal antibodies against: CD3, CD19, CD20, CD4, CD8, CD16, CD56, CD38, CD27, CD25, CD69, CD14, CD123, CD11c, HLA-DR, BDCA-1 and BDCA-2 were used for staining, followed by flow cytometric analysis.ResultsPreliminary results indicate that RA bone marrow compartment contained different proportions of activated CD4+ and CD8+ T cell, B-cells, NK-cells and macrophages than paired peripheral blood. Unlike in peripheral blood from RA and OA, where relatively small differences in cell phenotypes were detected, composition of bone marrow mononuclear cells differed substantially between these two diseases.ConclusionsPhenotypic differences between leukocytes from bone marrow and peripheral blood indicate that in RA bone marrow microenvironment provides stronger signals leading to activation and maturation of leukocytes than in OA. Thus, these data support notion that bone marrow actively participates in the pathogenesis of RA.AcknowledgementsThis work was partially supported by funds from the European Community's FP6 Project 018661 Autocure.     

CD133<Superscript>+</Superscript>CD44<Superscript>+</Superscript> Population Efficiently Enriches Colon Cancer Initiating Cells

Background  Previous reports have demonstrated that CD133⁺ cells or CD44⁺ cells might be cancer initiating cells (CIC) of colon cancer. However, the association between the two cell types is unclear. In this study, we evaluated the tumorigenicity of each population of human colon cancer divided by CD133 and CD44 using non-obese diabetic/severe combined immunodeficient (NOD/SCID) mice. Methods  Using the colon cancer cell lines HT29 and Caco2 we evaluated the change of expression status of CD133 or CD44 by a treatment with sodium butyrate (NaBT) that can induce cellular differentiation. Next, we prepared ten clinical samples of colon cancer and analyzed the expression and tumorigenicity of CD133 and CD44. Results  With NaBT treatment, CD44 expression was greatly downregulated in both HT29 and Caco2 (HT29: nontreatment versus treatment; 77.8% versus 0.6%, Caco2: 14.0% versus 0.4%, respectively), more than CD133 expression (HT29: nontreatment versus treatment; 90.1% versus 67.7%, Caco2: 98.9% versus 76.3%, respectively). In clinical samples, the percentages of CD133⁺ cells and CD44⁺ cells varied from 0.3% to 82.0% (mean 35.5%), and from 11.5% to 58.4% (mean 30.0%), respectively. Subcutaneous injection of CD133⁺ or CD44⁺ cells made a tumor in all mice (3/3 and 4/4, respectively). The combined analysis of CD133 and CD44 revealed that only the CD133⁺CD44⁺ population had the ability to produce a tumor (3/3). Conclusion  The findings demonstrate that, at present, the CD133⁺CD44⁺ population may be the best to identify tumor initiating cells of human colon cancer. Naotsugu Haraguchi: Awardee of Research Resident Fellowship from the Foundation for Promotion of Cancer Research (Japan) for the 3^rd Term Comprehensive 10- Year Strategy for Cancer Control.