Metabolism of paeoniflorin by rat intestinal flora in vitro / 中国中药杂志

In order to clarify the effect of intestinal flora on the absorption and metabolism of paeoniflorin in vivo, the metabolism of paeoniflorin by rat intestinal flora was studied under the in vitro anaerobic condition. Paeoniflorin was incubated with rat anaerobic intestinal flora for 48 h, and UPLC was used to detect the changes of paeoniflorin at different incubation time points under the following chromatographic conditions：WelchromTM C₁₈ chromatographic column (4.6 mm×100 mm, 5 μm), with 0.1% formic acid(A)-acetonitrile(B) as the mobile phase for gradient elution. The flow rate was 0.4 mL•min⁻¹, and column temperature was 30 ℃. UPLC-Q-TOF-MS with positive ion mode(ESI ion source) was applied to investigate the structural characterization of metabolic products. The structures of the metabolites were identified by accurate molecular weight, TOF-MS/MS fragmentation information, combined with retention time and literature data review, and the intestinal metabolic rules were then analyzed. After incubation for 24 h, the paeoniflorin was metabolized completely, and the resulting metabolites(albiflorin, albiflorinaglycone, deacylate albiflorin, deacylate albiflorin aglycone and paeonilactone-B) were detected in rat intestinal flora. The metabolic pathway analysis showed that the isolated rat intestinal flora first transformed peoniflorin into albiflorin, and then further metabolized by glucose removal, phenyl group removal, or four-membered ring pyrolysis and rearrangement. Paeoniflorin was gradually transformed into more hydrophobic metabolites with smaller molecular mass, which were better absorbed by the intestinal tract.

Host glial cell canceration induced by glioma stem cells in GFP/RFP dual fluorescence orthotopic glioma models in nude mice / 中华肿瘤杂志

<p><b>OBJECTIVE</b>During the process of tissue remodeling in human tumor transplantation models, the roles of the inoculated tumor cells and host tissue in tumor progression is still largely unknown. The aim of this study was to investigate the relationships and interactions between these two sides using GFP-RFP double fluorescence tracing technique.</p><p><b>METHODS</b>Red fluorescence protein (RFP) gene was stably transfected into glioma stem cell line SU3, then SU3-RFP cells were transplanted into the brain of athymic nude mice with green fluorescence protein (GFP) expression. After the intracerebral tumors were formed, the relationship and interaction between GFP cells and RFP cells were analyzed. Highly proliferative GFP cells were screened out, and monocloned with micro-pipetting. DNA content assay, chromosome banding and carcinogenicity test of the GFP cells were performed to observe the GFP cells' cancerous phenotype in nude mice.</p><p><b>RESULTS</b>In the transplantable tumor tissue, besides a great quantity of RFP cells, there were still a proportion of GFP cells and GFP/RFP fusion cells. The proportion of RFP cells, GFP cells and GFP/RFP cells were (88.99 ± 1.46)%, (5.59 ± 1.00)%, and (4.11 ± 1.020)%, respectively. Two monoclonal host GFP cells (H1 and H9) were cloned, which demonstrated the properties of immortality, loss of contact inhibition, and ultra-tetraploid when cultured in vitro. Both H1 and H9 cells expressed CNP, a specific marker of oligodendrocytes. The GFP cells also demonstrated 100% tumorigenic rate and high invasive properties in vivo.</p><p><b>CONCLUSIONS</b>In this glioma transplantation model, the transplanted tumor tissues contained not only transplanted glioma stem cells but also cancerous host GFP cells. Our findings offer important clues to further research on the relationships among different members in the tumor microenvironment.</p>

Incubation and application of transgenic green fluorescent nude mice in visualization studies on glioma tissue remodeling / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The primary reasons for local recurrence and therapeutic failure in the treatment of malignant gliomas are the invasion and interactions of tumor cells with surrounding normal brain cells. However, these tumor cells are hard to be visualized directly in histopathological preparations, or in experimental glioma models. Therefore, we developed an experimental human dual-color in vivo glioma model, which made tracking solitary invasive glioma cells possible, for the purpose of visualizing the interactions between red fluorescence labeled human glioma cells and host brain cells. This may offer references for further studying the roles of tumor microenvironment during glioma tissue remodeling.</p><p><b>METHODS</b>Transgenic female C57BL/6 mice expressing enhanced green fluorescent protein (EGFP) were crossed with male Balb/c nude mice. Then sib mating was allowed to occur continuously in order to establish an inbred nude mice strain with 50% of their offspring that are EGFP positive. Human glioma cell lines U87-MG and SU3 were transfected with red fluorescent protein (RFP) gene, and a rat C6 glioma cell line was stained directly with CM-DiI, to establish three glioma cell lines emitting red fluorescence (SU3-RFP, U87-RFP, and C6-CM-DiI). Red fluorescence tumor cells were inoculated via intra-cerebral injection into caudate nucleus of the EGFP nude mice. Tumor-bearing mice were sacrificed when their clinical symptoms appeared, and the whole brain was harvested and snap frozen for further analysis. Confocal laser scanning microscopy was performed to monitor the mutual interactions between tumor cells and host brain cells.</p><p><b>RESULTS</b>Almost all the essential tissues of the established EGFP athymic Balb/c nude mice, except hair and erythrocytes, fluoresced green under excitation using a blue light-emitting flashlight with a central peak of 470 nm, approximately 50% of the offsprings were nu/nu EGFP+. SU3-RFP, U87-RFP, and C6-CM-DiI almost 100% expressed red fluorescence under the fluorescence microscope. Under fluorescence microscopic view, RFP+ cells were observed growing wherever they arrived at, locating in the brain parenchyma, ventricles, and para-vascular region. The interactions between the transplanted tumor cells and host adjacent cells could be classified into three types: (1) interweaving; (2) mergence; and (3) fusion. Interweaving was observed in the early stage of tumor remodeling, in which both transplantable tumor cells and host cells were observed scattered in the tumor invading and spreading area without organic connections. Mergence was defined as mutual interactions between tumor cells and host stroma during tumorigenesis. Direct cell fusion between transplantable tumor cells and host cells could be observed occasionally.</p><p><b>CONCLUSIONS</b>This study showed that self-established EGFP athymic nude mice offered the possibility of visualizing tumorigenesis of human xenograft tumor, and the dual-color xenograft glioma model was of considerable utility in studying the process of tumor remodeling. Based on this platform, mutual interactions between glioma cells and host tissues could be observed directly to further elucidate the development of tumor microenvironment.</p>

Preliminary studies on cell derivation of neovascularization in human glioma and its functional evaluation / 中华肿瘤杂志

<p><b>OBJECTIVE</b>The finding of vasculogenic mimicry (VM) in many solid tumors indicates that tumor cells themselves could participate in the construction of tumor vessels. However the origin of these cells is still not fully elucidated, and whether these vessels have the ability of blood-supply is still unclear. Preliminary studies were performed to investigate whether part of tumor neovascularity is derived from tumor stem cells (TSCs) and whether TSCs-derived vessels are functional.</p><p><b>METHODS</b>Transplanted glioma tissues obtained from subcutaneous and orthotopic transplantation nude mouse models were processed into paraffin sections. In order to identify the cell origin and types of tumor vessels, sections were stained with CD31, CD34, CD133, GFAP, Ki67 and HLA, respectively. CD34-PAS staining was performed as well. A part of tumor-bearing mice were perfused with activated carbon through the systemic circulation and the distribution of activated carbon was observed.</p><p><b>RESULTS</b>CD34-PAS staining showed that endothelium-dependent vessels (CD34(+), PAS(+)), VM vessels (CD34(-), PAS(+)), and the MVs (CD34(+), PAS(-)) could be seen in the transplantated tumors. Activated carbon particles were observed in all three types of vessels. CD31(+) cells adherent to the luminal surface of vessel wall. CD34(+) cells distributed along the vessels as well, but morphologically were more like a transition type between tumor cells and endothelial cells. Human specific Ki67 and HLA positive cells could be seen in the tumor vessels indicating that these vessels were derived from human tumor cells. Moreover, cells of tumor vessels were proved to be constructed by human tumor cells mainly and fusion cells of host cells and tumor cells under confocal microscope.</p><p><b>CONCLUSIONS</b>Three types of blood supply sources including endothelium-dependent vessels, vasculogenic mimicry (VMs) and mosaic vessels (MVs) exist in transplantation tumors of human glioma. Glioma stem and progenitor cells (GSCPs) have the potential to differentiate and transdifferentiate into VMs and MVs.</p>

Expression of SV40Tag, Rb and IRS-1 in glioma detected by tissue microarray and their relation with tumorigenesis and progression of gliomas / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To determine the expression of SV40Tag, Rb and IRS-1 in gliomas and to identify their function in gliomagenesis and progression.</p><p><b>METHODS</b>Tissue microarrays were constructed containing 118 samples including human glioma and meningioma, experimental glioma, and normal human brain tissue. The expression of SV40Tag, Rb, IRS-1, SV40Tag combined with Rb, and SV40Tag combined with IRS-1 were assayed by immunofluorescence or immunohistochemical techniques. The expression ratio and level were analyzed.</p><p><b>RESULTS</b>The expressions of SV40Tag, Rb and IRS-1 were detected in gliomas and benign brain tumors. Their positive expression rate in glioma was 65.9%, 64.6% and 48.8%, respectively, with a statistically non-significant difference between the malignant and benign brain tumors. The malignant degree was positively correlated with SV40Tag and IRS-1, but negatively correlated with Rb expression. The combined expression rate of SV40Tag and Rb was 51.2%, and the combined expression rate of SV40Tag and IRS-1 was 40.2%. In the normal human brain tissue only the expression of Rb (77.8%, 7/9) and IRS-1 (22.2%, 2/9) were detected, but expression of SV40Tag could not be observed.</p><p><b>CONCLUSION</b>Our findings that no expression of SV40Tag was observed in normal human brain tissue indicates that expression of SV40Tag may play an important role in the pathogenesis of glioma. It may be assumed that after SV40 virus invading human body, Rb disfunction and IRS-1 activation promote the malignant transformation of cells, which could be one of important factors in pathogenesis and procession of glioms.</p>

Ultrastructural analysis of glioma stem cells-progenitors / 中华肿瘤杂志

<p><b>OBJECTIVE</b>It is well known that glioma stem cells-progenitors (GSCP) proliferate indefinitely and hardly differentiate in vitro, however, the reasons remain unknown. The aim of this study was to explore the ultrastructural basis of GSCP.</p><p><b>METHODS</b>GSCP, kept by our laboratory, were collected, embedded, and cut into ultrathin sections and observed under the transmission electron microscope.</p><p><b>RESULTS</b>A single GSCP usually had relatively well developed mitochondria, Golgi apparatuses, ribosomes, and undeveloped rough endoplasmic reticulum, but seldom lysosomes and no typical autophagosomes were found, and the nuclear-cytoplasmic ratio was high. The nuclei frequently contained huge amounts of euchromatin and a small quantity of heterochromatin, and in most nuclei there were only one nucleolus, however, two or more nucleoli were also common. Typical apoptotic cells could hardly be found in tumor-spheres, and between neighboring cells in tumor-spheres there were incompletely developed desmosomes or intermediate junction.</p><p><b>CONCLUSION</b>The ultrastructural features of glioma stem cells-progenitors showed that BTSCP were very primitive and the lack of autophagy and the underdevelopment of some other cellular organelles are probably the reasons for the differential inhibition of GSCPs.</p>

Studies on the target cells and molecules with sodium valproate induced differential of human glioma cells / 中华外科杂志

<p><b>OBJECTIVE</b>To investigate the target cells and molecules with sodium valproate induced differentiation of human glioma cells.</p><p><b>METHODS</b>Nude mice bearing human glioma xenogenic graft subcutaneously were treated with sodium valproate. The expressions of HDAC1 and Tob genes of xenografts were analyzed with semiquantitative RT-PCR. The CD133+ cells (BTSCs) were isolated from glioma specimens by immunomagnetic sorting, and cultured in the medium containing FCS or in the serum-free medium supplemented with growth factors, respectively, followed by treatment with sodium valproate in vitro for 21 days. The cell surface markers were detected with flow cytometry and confocal microscopy.</p><p><b>RESULTS</b>Sodium valproate inhibited the growth of subcutaneous xenografs bearing on nude mice (P<0.05), and up-regulated the HDAC1 expression (P<0.01), down-regulated the Tob expression (P<0.05). The cell surface markers of BTSCs were detected by flow cytometry after sodium valproate treatment for 21 days. In the FCS group, the GFAP or beta-tubulin III positive cells increased significantly (P<0.01), but in the growth factor group, no statistical differences were observed in the GFAP or beta-tubulin III expression (P>0.05). The results of confocal microscopy indicated that the GFAP+ or beta-tubulin III+ cells coexpressed with Nestin.</p><p><b>CONCLUSIONS</b>HDAC1 and Tob genes were the potential target molecules in reversion of the differential inhibition of human glioma cells with sodium valproate. The BTSCs undergoing the processes of differentiation were the target cells for sodium valproate.</p>

CDK1 expression and effects of CDK1 silencing on the malignant phenotype of glioma cells / 中华肿瘤杂志

<p><b>OBJECTIVE</b>Our previous cDNA array data have shown that expression level of CDK1 increased along with the malignant progression of ganglioglioma, and decreased with the differentiation process of neural stem cells. The purpose of this study was to investigate the CDK1 expression levels in gliomas and the effects of CDK1 knockdown on phenotype of glioma cells.</p><p><b>METHODS</b>Glioma tissue array was constructed, which was composed of surgical specimens of gliomas with different malignancy grades, glioma xenografts in nude mice, cellular spheroids of brain tumor stem cells, normal neural stem cells and glioma cell line. CDK1 expression was detected in glioma tissue array with immunohistochemical techniques. CDK1 expression in human brain glioma cell line and relevant xenogeneic graft tumor was inhibited by retroviral vectors expressing short hairpin RNAs (shRNAs). Both in vitro and in vivo changes of biological characteristics were further observed.</p><p><b>RESULTS</b>The expression level of CDK1 increased along with the malignancy progression of glioma in clinical specimens. The positive expression rates of CDK1 in human brain glioma tissues were 22.2% (grade I), 40.0% (grade II), 69.6% (grade III) and 78.6% (grade IV), P = 0.01, respectively. The positive expression rate of CDK1 in glioma cell line and implanted xenografts was similar as the clinical tumors with high malignancy, and higher than those in neural stem cells and brain tumor stem cells (P = 0.0014). Expression of CDK1 was high in human fetal brain tissues and bone marrows of nude mice, but low in normal adult human brain tissues. Downregulation of CDK1 inhibited the proliferation activities notably both in SHG-44 cells in vitro and relevant xenogeneic graft tumors, and induced apoptosis of tumor cells prominantly as well.</p><p><b>CONCLUSION</b>Overexpression of CDK1 may promote oncogenesis and progression of human gliomas. Downregulation of CDK1 expression can inhibit the proliferation activities of human malignant gliomas.</p>

Isolation and culture of tumor stem cells from human brain glioma tissues / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To isolate and culture tumor stem cells from glioma tissues obtained at surgical operation and to study their biological characteristics.</p><p><b>METHODS</b>Glioma tissues obtained from surgically resected specimens of 8 patients were fully chopped, trypsinized, and filtered to prepare single cell suspensions. The cells were cultured in serum-free medium with EGF, LIF and bFGF. CD133(+) cells were purified by magnetic cell sorting, and cultured continuously in vitro to obtain tumor cell spheres. Tumor stem cells of the 5th passage were induced to differentiate with 10% FBS, and expression of cell differentiation markers such as Nestin, MAP2, GFAP was evaluated with immunocytochemistry techniques.</p><p><b>RESULTS</b>CD133(+) cells were successfully separated and cultured from one anasplastic mixed astrocyte-ependymocyte type glioma specimen. These cells maintained a sphere-like growth status in vitro (3 months, 14 passages), and can self-renew, proliferate and conditionally differentiate into MAP2(+) and GFAP(+) cells. However, CD133(-) cells did not possess these properties.</p><p><b>CONCLUSION</b>Glioma tissue contains tumor stem cells. Those cells can be cultured and passaged in vitro for a long term, and therefore to offer new approaches for studying cellular and molecular biology of glioma.</p>

Establishment of malignant progression associated gene expression profiles in human brain glioma / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To establish malignant progression associated gene expression profiles in human brain glioma.</p><p><b>METHODS</b>The primary (WHO grade II), recurrent (WHO grade III) and re-recurrent (WHO grade IV) glioma specimens were sequentially collected from one single patient. Gene expression of different tumor specimens and normal brain tissue of the same patient was compared by microarrary techniques.</p><p><b>RESULTS</b>197 differentially expressed genes with differential ratio > or = 3 were observed when compared with normal brain tissue. When the specimens (3 tumor, 1 normal brain) were paired with each other, 7 groups containing 489 genes (upregulated 193, downregulated 296) were observed. According to the descending frequency of the 109 genes with known function, they were the genes associated with development, metabolism, differentiation, signal transduction, DNA binding transcription, cellular receptor, immunity, ion-channel transportation, protein translation, cell backbone motion, stress, protooncogene and anti-oncogene and cell apoptosis, respectively.</p><p><b>CONCLUSION</b>From the 197 differentially expressed genes found in one glioma patient experiencing tumor malignant progression, 17 genes screened out by bioinformatics assay, may offer valuable information on molecular mechanisms on genesis and malignant progression of glioma.</p>