Intratumor heterogeneity, microenvironment, and mechanisms of drug resistance in glioma recurrence and evolution / 医学前沿

Glioma is the most common lethal tumor of the human brain. The median survival of patients with primary World Health Organization grade IV glioma is only 14.6 months. The World Health Organization classification of tumors of the central nervous system categorized gliomas into lower-grade gliomas and glioblastomas. Unlike primary glioblastoma that usually develop de novo in the elderly, secondary glioblastoma enriched with an isocitrate dehydrogenase mutant typically progresses from lower-grade glioma within 5-10 years from the time of diagnosis. Based on various evolutional trajectories brought on by clonal and subclonal alterations, the evolution patterns of glioma vary according to different theories. Some important features distinguish the normal brain from other tissues, e.g., the composition of the microenvironment around the tumor cells, the presence of the blood-brain barrier, and others. The underlying mechanism of glioma recurrence and evolution patterns of glioma are different from those of other types of cancer. Several studies correlated tumor recurrence with tumor heterogeneity and the immune microenvironment. However, the detailed reasons for the progression and recurrence of glioma remain controversial. In this review, we introduce the different mechanisms involved in glioma progression, including tumor heterogeneity, the tumor microenvironment and drug resistance, and their pre-clinical implements in clinical trials. This review aimed to provide new insights into further clinical strategies for the treatment of patients with recurrent and secondary glioma.

Serum microRNA expression profiling revealing potential diagnostic biomarkers for lung adenocarcinoma / 中华医学杂志(英文版)

BACKGROUND@#Recent studies have demonstrated that microRNAs (miRNAs) in the blood circulation can serve as promising diagnostic markers for cancers. This four-stage study aimed at finding serum miRNAs as potential biomarkers for lung adenocarcinoma (LA) diagnosis.@*METHODS@#The study was carried out between 2016 and 2017. The Exiqon miRNA qPCR panel (3 LA vs. 1 normal control [NC] pooled serum samples) was used for initial screening to acquire miRNA profiles. Thirty-five dysregulated miRNAs were further evaluated in the training (24 LA vs. 24 NCs) and testing stages (110 LA vs. 110 NCs) using quantitative real-time polymerase chain reaction assays.@*RESULTS@#Four serum miRNAs (miR-133a-3p, miR-584-5p, miR-10b-5p, and miR-221-3p) were significantly overexpressed in LA patients compared with NCs. The diagnostic value of the four-miRNA panel was validated by an external cohort (36 LA vs. 36 NCs). The areas under the receiver operating characteristic curve of the four-miRNA panel in the training, testing, and external validation stages were 0.734, 0.803, and 0.894 respectively. Meanwhile, the expression level of miR-221-3p was much higher in LA tumor samples than that in the adjacent normal tissues (19 LA vs. 19 NCs). The expression level of miR-10b-5p was also elevated in the serum-derived exosomes samples (18 LA vs. 18 NCs). The expression of miR-133a-3p, miR-584-5p, and miR-10b-5p was significantly elevated in LA patients with epidermal growth factor receptor mutation compared with NCs.@*CONCLUSION@#The study established a four-miRNA signature in serum that could improve the diagnostic capability of LA.

Human umbilical cord mesenchymal stem cells combined with immunotherapy for the treatment of type 1 diabetic mice / 中国组织工程研究

BACKGROUND: Type l diabetes mellitus is a T cell-mediated autoimmune disease resulting in pancreatic islet cell damage. In this study, immunotherapy was used to deal with type l diabetes mellitus and stem cell transplantation was used to repair damaged islet p cells, attempting to explore a new treatment for type l diabetes mellitus. OBJECTIVE: To observe the efficacy of human umbilical cord mesenchymal stem cells combined with immunotherapy for the treatment of type l diabetic mice. METHODS: Fifty BALB/c Foxp3-DTR-EGFP positive mice were selected, six of which were randomly selected as normal control group and the remaining of which were intraperitoneally injected with streptozotocin and diphtheria toxin to prepare an animal model of type l diabetes mellitus. After successful modeling, randomization was performed in model mice and there were four groups: model group (normal saline), immunotherapy group (subcutaneous injection of dexamethasone (10 μg) and insulin (10 μg) mixture), cell transplantation group (injection of human umbilical cord mesenchymal stem cells (1 X106 cells per mouse) through the tail vein, and combined treatment group (the combination of immunotherapy and cell transplantation as described above). At 4 weeks after treatment, changes in blood glucose, C-peptide, body mass, pancreatic histopathology and insulin-positive area were observed in each group. RESULTS AND CONCLUSION: (1) Compared with the normal control group, the blood glucose level of the model group increased (P < 0.01) the C peptide level and body mass decreased (P < 0.01), and the islet was severely atrophied, with decreased number of islet cells and reduced insulin-positive area. (2) Compared with the model group, the blood glucose level of the immunotherapy group decreased (P > 0.05), the C-peptide level and body mass did not change significantly (P > 0.05), the islet cells increased in number, and the insulin-positive area increased. (3) Compared with the model group, the blood glucose level of the cell transplantation group and the combined treatment group decreased (P > 0.05), the C peptide level and body mass increased (P < 0.05), the islet cells increased in number, and the insulin-positive area increased. These findings reveal that either human umbilical cord mesenchymal stem cells or immunotherapy can improve the islet function of type l diabetic mice, and the combination treatment has better outcomes.

Transplantation of islet-like cells from human umbilical cord mesenchymal stem cells at different induced stages for the treatment of diabetic mellitus / 中国组织工程研究

BACKGROUND:In previous studies,the human umbilical cord mesenchymal stem cells (hUC-MSCs) have been successfully differentiated into islet-like cells in vitro,and insulin expressions have been found.OBJECTIVE:To compare the therapeutic effects of different induced stages of islet-like cells differentiated from hUC-MSCs in a diabetic rat in vivo,so as to find the most suitable induced time in vitro and provide a theoretical basis for clinical treatment of diabetes mellitus.METHODS:Passage 3 hUC-MSCs were differentiated into islet-like cells after 7,14,21,28 days of oriented induction.Eighty male healthy Wistar rats,clean grade,were used in the study.Except eight rats in normal control group,all the rats were injected with streptozotocin at a dose of 70 mg/kg to establish diabetic models.The rats at 10 days after successful modeling were randomly divided into model control group,non-induced group,7-day induction group,14-day induction group,21-day induction group and 28-day induction group.Rats in the normal control group and model control group were given 2 mL of culture medium without any cells and rats in the other groups were implanted withcorresponding cell suspension (2x106 cells) via tail vein for two sessions with an interval of 2 weeks.The blood glucose level,body mass and serum insulin level were detected during the treatment process.The rats were executed to observe the structure changes of each organ at 4 weeks after the second cell transplantation.RESULTS AND CONCLUSION:(1) Compared with the model control group,the body mass and the serum insulin level significantly increased and the blood glucose levels significantly decreased in all the transplantation groups (P ＜ 0.05),and the therapeutic effect was best in the 28-day induction group.(2) Compared with the model control group and normal control group,the frozen sections in all the transplantation groups showed that the morphological structures of the liver and kidney were clear with no abnormal changes,such as necrosis and fibrosis,after transplantation.These experimental results show that it is relatively safe and effective to transplant the different induced stages of islet-like cells induced by hUC-MSCs in the treatment of diabetes mellitus,and the therapeutic effect of islet-like cells at 28 days of in vitro induction is most obvious.

Changes of insulin and nestin expression during the differentiation of human umbilical cord mesenchymal stem cells into islet-like cells / 中国组织工程研究

BACKGROUND:Domestic and international studies have confirmed that human umbilical cord mesenchymal stem cel s could be induced to differentiate into islet-like cel s, but little is reported about the changes of insulin and nestin expressions during the differentiation phase. OBJECTIVE:To observe the changes of insulin and nestin expressions during the differentiation of human umbilical cord mesenchymal stem cel s into islet-like cel s. METHODS:Human umbilical cord mesenchymal stem cel s were cultured using UltraCULTURE medium in vitro. Stem cel s were cultured for three generations to observe cel morphological changes under an inverted microscope, to test immunophenotype by flow cytometry, and to identify the capacity of osteogenesis and adipogenic differentiation. Induction protocol was divided into two stages. In stage 1, stem cel s were induced for 14 days in the UltraCULTURE medium with 4 nmol/L activin A, 25μg/L epidermal growth factor, 100μg/Lβ-nerve growth factor, 10 mmol/L nicotinamide. In stage 2, the cel s were cultured in the UltraCULTURE medium with 1%insulin-transferin-selenium, 10 mmol/L nicotinamide, 10μg/L basic fibroblast growth factor for an additional 14 days. The expressions of nestin and insulin in those differentiated cel s were tested by flow cytometry, and zinc ion expression in the islet-like cel clusters was identified by dithizone staining. RESULTS AND CONCLUSION:During the differentiation process, the insulin level was increased gradual y in the induction group and reached a higher level on day 28, but the insulin expression showed negative in the control group. In addition, on day 14 of induced differentiation, the nestin expression reached the peak and then gradual y reduced along with the prolonged inductive time. On day 28 of induction, islet-like cel clusters formed and were positive for dithizone staining. In this experiment, the umbilical cord mesenchymal stem cel s were successful y induced and differentiated into islet-like cel s, accompanied with the variation of insulin and nestin expression.