Xifeng Fei

Expression of miR-125b in the new, highly invasive glioma stem cell and progenitor cell line SU3.

MicroRNA (miR)-125b has been shown to play a potential role in the development of glioma stem cells. However, the relationship between miRNA and glioma stem cells is still elusive. This study was designed to elucidate this potential relationship. We established a highly invasive glioma stem cell and progenitor (GSCP) cell line SU3. SU3 cell suspensions were injected into nude mice brains in situ, and the invasiveness of graft tumors was analyzed using hematoxylin and eosin staining as well as immunohistochemistry. Real-time polymerase chain reaction (PCR) was used to measure the expression levels of miR-125b in SU3 and other cells. In vitro, SU3 cells expressed CD133 and nestin as well as differentiation markers glial fibrillary acidic protein (GFAP) and β-tubulin III, which were consistent with the characteristics of glioma stem cells. Scratch assays indicated that the migration ability of SU3 cells was stronger than that of U251 stem cells (U251s). In vivo, SU3 cells invaded into each part of the mouse brain from the caudate nucleus in a diffuse pattern and highly expressed invasive and proliferative cell markers matrix metalloprotease 2 (MMP2), MMP9, and Ki-67. Real-time PCR results revealed that the levels of miR-125b and MMP9 were significantly higher in SU3 and SU2, also a highly invasive GSCP cell line we established before, than in U251s. High expression of miR-125b both in newly established GSCPs, SU3, and long-term cultured GSCPs, SU2 suggests that miR-125b exhibits oncogene-like behavior. This behavior should be considered in further studies of miR-125b in cancer stem cells. Furthermore, MMP9, which plays a role in cancer stem cell invasion, may be a target gene of miR-125b.

miR-22 inhibits the proliferation, motility, and invasion of human glioblastoma cells by directly targeting SIRT1

Recently, microRNAs (miRNAs), a kind of small and non-coding RNA, can target the downstream molecules. Increasing evidence demonstrates that miRNAs meditate the onset and progression of a variety of tumors. In the present study, we carried out gene transfection, western blot, and reverse transcription PCR (RT-PCR) to explore the role of miR-22 in glioblastoma tissues and cell lines. Here, we verified that the expression of miR-22 was downregulated in glioblastoma tissues and cells rather than matched non-tumor tissues and normal human astrocyte (NHA) cells (p < 0.001). By contrast, SIRT1 messenger RNA (mRNA) and protein were upregulated in glioblastoma tissues and cells (p < 0.001). In vitro miR-22 mimics interfered with cell proliferation, migration, and invasion of U87 and U251 cells. Mechanically, the 3′-untranslated regions (3′-UTRs) of SIRT1 were a direct target of miR-22, leading to the decreased expression of SIRT1 protein in U87 and U251 cells. Meanwhile, miR-22 mimics also inhibited the expression of epidermal growth factor receptor (EGFR) and matrix metallopeptidase 9 (MMP9). In conclusion, miR-22 inhibited cell proliferation, migration, and invasion via targeting the 3′-UTR of SIRT1 in the progression of glioblastoma and miR-22-SIRT1 pathway can be recommended as a potential target for treatment of glioblastoma.

Knockdown of Cathepsin L promotes radiosensitivity of glioma stem cells both in vivo and in vitro.

The presence of glioma stem cells (GSCs) in tumor is relevant for glioma treatment resistance. This study assessed whether knockdown of Cathepsin L can influence GSC growth, tumor radiosensitivity, and clinical outcome. Protein levels of Cathepsin L and stem cell markers (CD133 and Nestin) were analyzed in samples from 90 gliomas of different WHO grades and 6 normal brain tissues by immunohistochemistry. Two glioma stem cell lines with overexpressed Cathepsin L were stably transfected with Cathepsin L short hairpin RNA expression vectors. The effects of Cathepsin L inhibition on radiosensitivity, self-renewal, stemness, DNA damage, and apoptosis were evaluated. In addition, an intracranial animal model and subcutaneous tumor xenografts in nude mice were used to assess tumor response to Cathepsin L inhibition in vivo. Our results proved that expressions of Cathepsin L and CD133, but not of Nestin, correlated with malignant grades of glioma tissues. GSCs with high Cathepsin L and CD133 co-expression were extraordinarily radioresistant. Cathepsin L inhibition with radiotherapy significantly reduced GSC growth, promoted apoptosis, and improved radiosensitivity. Knockdown of Cathepsin L resulted in a dramatic reduction of CD133 expression, as well as the decreased phosphorylation of DNA repair checkpoint proteins (ATM and DNA-PKcs). Furthermore, combination of Cathepsin L inhibition and radiotherapy potently blocked tumor growth and decreased blood vessel formation in vivo. Taken together, these findings suggest Cathepsin L as a promising therapeutic target for clinical therapy in GBM patients.

Glioma initiating cells contribute to malignant transformation of host glial cells during tumor tissue remodeling via PDGF signaling

INTRODUCTION Glioma initiating cells (GICs) play important roles in tumor initiation and progression. However, interactions between tumor cells and host cells of local tumor microenvironment are kept largely unknown. Besides GICs and their progeny cells, whether adjacent normal glial cells contribute to tumorigenesis during glioma tissue remodeling deserves further investigation. METHODS Red fluorescence protein (RFP) gene was stably transfected into human GIC cells lines SU3 and U87, then were transplanted intracerebrally into athymic nude mice with whole-body green fluorescence protein (GFP) expression. The interactions between GICs and host cells in vivo were observed during tissue remodeling processes initiated by hGICs. The biological characteristics of host glial cells with high proliferation capability cloned from the xenograft were further assayed. RESULTS In a SU3 initiated dual-fluorescence xenograft glioma model, part of host cells cloned from the intracerebral tumors were found acquiring the capability of unlimited proliferation. PCR and FISH results indicated that malignant transformed cells were derived from host cells; cell surface marker analysis showed these cells expressed murine oligodendrocyte specific marker CNP, and oligodendrocyte progenitor cells (OPCs) specific markers PDGFR-α and NG2. Chromosomal analysis showed these cells were super tetraploid. In vivo studies showed they behaved with high invasiveness activity and nearly 100% tumorigenic ratio. Compared with SU3 cells with higher PDGF-B expression, GICs derived from U87 cells with low level of PDGF-B expression failed to induce host cell transformation. CONCLUSIONS Primary high invasive GICs SU3 contribute to transformation of adjacent normal host glial cells in local tumor microenvironment possibly via PDGF/PDGFR signaling activation, which deserved further investigation.

Experimental research of host macrophage canceration induced by glioma stem progenitor cells

The involvement of tumor-associated macrophages in tumor progression is an indisputable fact. However, whether the growth-promotion effects of macrophages towards tumors in the aggressive stage affect their own canceration remains unknown. In the present study, human glioma stem/progenitor cells transfected with red fluorescent protein gene (SU3-RFP) were seeded inside the abdominal cavity of transgenic nude mice, of which all nucleated cells could express green fluorescent protein (GFP), forming a tumor model with a double-color RFP/GFP fluorescent tracer. Ascites and tumor nodules from tumor-bearing mice were cultured, then the GFP+ cells were separated for clonal culture and further related phenotypic characterization and tumorigenicity tests. It was observed that the GFP+ cells isolated from ascites and solid tumors exhibited unlimited proliferative potential; the monoclonal cells were mouse-original, had a cancer cell phenotype and expressed the macrophage marker protein CD68. Thus, in the abdominal tumor model with double-color fluorescent tracer, macrophages recruited by tumor cells not only promoted tumor cell growth, but also exhibited their own canceration. This discovery is significant for the further study of tumor tissue remodeling and the tumor microenvironment.

Cathepsin L is involved in X-ray-induced invasion and migration of human glioma U251 cells.

An important therapeutic method of glioblastoma, the most common primary brain tumor, is radiotherapy. However, several studies reported recently that radiation could also promote the invasion and migration of malignant tumor. Herein, we have identified that a significant increase of migration and invasiveness of human glioma U251 cells undergoing X-ray was observed compared to controls, accompanied by the increase of cathepsin L (CTSL), which is a lysosomal cysteine protease overexpressed and secreted by tumor cells. To verify if there was a relationship between CTSL and the X-ray-induced glioma invasion, a CTSL specific inhibitor Z-FY-CHO or a short hairpin RNA interference was used to pretreat U251 cells. As a result, the cell invasion and migration was impaired via down-regulation of CTSL. Additionally, a marked reduction of the cell-signaling molecules Rho kinase was also detected compared with controls. We also found that CTSL is involved in EMT progress: both in vitro and in clinical specimens. Overall, our findings show that CTSL is an important protein which mediates cell invasion and migration of human glioma U251 cells induced by X-ray, and the inhibition of CTSL expression might diminish the invasion of U251 cells by reducing the activity of RhoA and CDC42 as well as EMT positive markers.

Malignant transformation of host stromal fibroblasts derived from the bone marrow traced in a dual-color fluorescence xenograft tumor model

Solid tumors are abnormal tissues containing tumor and non-tumor cells, also known as tumor stromal cells. However, the malignant potential of tumor stromal cells remains largely unknown. The aim of the present study was to investigate the malignant potential of host bone marrow‑derived stroma cells in transplanted subcutaneous tumors of the glioma stem/progenitor cells (GSPCs) labeled using the dual-color fluorescent tracer technique. The previously established human glioma stem/progenitor cell line SU3 was transfected with red fluorescence protein (SU3-RFP) and transplanted subcutaneously into green fluorescent protein (GFP) transgenic nude mice and chimeric mice in which GFP was only expressed by bone marrow-derived cells (BMDCs). The xenograft tumors were subcultured in vitro and two immortalized GFP-expressing stromal cell lines were cloned from the transplanted tumors. The two cloned cell lines showed an accelerated growth rate, loss of cell contact inhibition, high cloning efficiency, and high DNA content and telocentric (murine) chromosomes with heteroploid characteristics. The tumorigenesis rate (10/10, 1x10(6)) of these host stromal cells was further evidence of malignant transformation. Immunofluorescence assay of the two host cell lines showed that they expressed fibroblast markers such as FAP, S100A4 and α-SMA, as well as mesenchymal cell markers such as CD44 and CD105. In conclusion, bone marrow-derived stromal fibroblasts recruited to tumors have the potential for malignant transformation induced by the tumor microenvironment, which provides new evidence for the role of the stroma in malignant transformation.

Clinical Observation of Treatment of Chronic Subdural Hematoma With Novel Double Needle Minimally Invasive Aspiration Technology.

OBJECTIVE The aim of the present study was to explore the clinical effects, including the prevention of complications, of the treatment of chronic subdural hematoma with double needle aspiration. METHODS The clinical data of 31 patients with chronic subdural hematoma treated by double YL-1 needle double skull drilling and 31 controls treated by traditional drilling and drainage were analyzed retrospectively. RESULTS In the YL-1 needle group, only 1 patient was with hematoma recurrence, 1 patient was with intracranial pneumocephalus, and the remaining patients who were followed up for 3 months achieved a clinical cure. In the traditional drilling and drainage group, 13 patients were with hematoma recurrence within 3 months after the operation and 7 patients were with postoperative intracranial pneumocephalus. CONCLUSIONS The method of double YL-1 needle is better than the traditional drilling and drainage method for the treatment of chronic subdural hematoma because it reduces the postoperative recurrence rate and complications.Objective: The aim of the present study was to explore the clinical effects, including the prevention of complications, of the treatment of chronic subdural hematoma with double needle aspiration. Methods: The clinical data of 31 patients with chronic subdural hematoma treated by double YL-1 needle double skull drilling and 31 controls treated by traditional drilling and drainage were analyzed retrospectively. Results: In the YL-1 needle group, only 1 patient was with hematoma recurrence, 1 patient was with intracranial pneumocephalus, and the remaining patients who were followed up for 3 months achieved a clinical cure. In the traditional drilling and drainage group, 13 patients were with hematoma recurrence within 3 months after the operation and 7 patients were with postoperative intracranial pneumocephalus. Conclusions: The method of double YL-1 needle is better than the traditional drilling and drainage method for the treatment of chronic subdural hematoma because it reduces the postoperative recurrence rate and complications.

Application of YL-1 Needle in Chronic Subdural Hematoma Treatment for Super-Aged Patients

Objective: The proportion of the super-aged population (at the age of 80 or above) in patients with chronic subdural hematoma (CSDH) and the incidence of CSDH of the population have been increasing. Since it is widely accepted that YL-1 needle is effective in CSDH treatment, this paper aimed to probe into the efficacy of YL-1 needle in minimally invasive surgery for super-aged (at the age of 80–90) CSDH patients. Methods: A retrospective analysis on the clinical information of 17 super-aged CSDH patients having received the YL-1 needle puncture treatment provided by the hospital from May 2012 to December 2016 was performed. At the same time, another 19 CSDH patients (ages 60–79) who were hospitalized during the same period were randomly selected to form a control group. The same surgical treatment was provided for both groups to observe and compare the treatment efficacy. Results: The patients of both groups were cured and discharged. Among the super-aged patients, there was 1 patient with postoperative hematoma recurrence, 1 patient with pneumocephalus, and 1 patient with wound infection; among the aged patients, 1 reported postoperative recurrence and 2 had pneumocephalus; The average length of stay of the super-aged group was 9.235 ± 2.948 days while that of the aged group was 7.316 ± 3.660 days, which showed no statistical difference. Conclusion: The YL-1 needle puncture treatment is safe and efficacious for both the super-aged and the aged CSDH patients.

Differentiation of Glioma Stem Cells and Progenitor Cells into Local Host Cell-Like Cells: A Study Based on Choroidcarcinoma Differentiation of Choroid Plexus of GFP Transgenic Nude Mouse.

The idea of multiple differentiation capacity of glioma stem cells and progentior cells (GSCPs) has been accepted by most of the researchers, but the effect of local environment on the differentiation of GSCPs is unclear. GSCPs SU2 and CM-Dil-stained C6 cells (C6-Dil) were injected into the brain of GFP transgenic nude mice. The xenografts were sectioned. Morphological changes of tumor cells that resided in the choroid plexus, molecular markers expression, and the relationship between the original tumor cells and host cells were studied carefully. The tumorigenicity rate was 40/40 (100%) in all of the inoculated nude mice. Cell morphology and molecular expression of neoplasm settled in the choroid plexus showed that choroidcarcinoma derived from GSCPs was developed. These results showed that GSCPs may have the multiple differentiation capacity, which can be induced by the local environment of host brain as NSCs, and cell fusion may play an important role in the transformation.