Mesenchymal stem cells (MSCs) are multipotent cells traditionally derived from bone marrow (BM). They have been demonstrated to be widely applied in tissue regeneration and cellular therapy. As an alternative to BM, an umbilical cord (UC) is considered as a potential source of MSCs. Here, we showed that human UC-MSCs were easily isolated by a single enzymatic digestion and characteristic of plastic adherence and fibroblast-like morphology. UC-MSCs isolation was successful in 15 of 15 samples. The colony-forming unit-fibroblast frequency was obtained 54 ± 1.33 from 10³ UC-MSCs at passage 3, and the doubling time was (24.15 ± 0.49) h. Almost 10¹⁰ UC-MSCs were largely produced in about 30 days. By flow cytometry analysis, the adherent cells displayed an abundant presence of CD73, CD90 and CD105 and absence of CD34, CD45 and HLA-DR. When cultured in differentiation media, they can be differentiated into adipocytes, osteocytes and chondrocytes. RT-PCR reactions confirmed that their multidifferentiation related genes were positive. Moreover, stem cell-related transcription factors Nanog, Oct-4 and Sox-2 were positively expressed in UC-MSCs. On the basis of these findings, the single enzyme method is a good method to obtain large-scale production of MSCs from whole human UC in a short time, and the UC can be considered as a novel and convenient source of adult MSCs displaying high expansion potential and primitive pluripotent stem cells.
Long noncoding RNA DANCR confers cytarabine resistance in acute myeloid leukemia by activating autophagy via the miR-874-3P/ATG16L1 axis
AbstractAutophagy is an important mechanism involved in the regulation of acute myeloid leukemia (AML) chemoresistance. The long noncoding RNA (lncRNA) DANCR exhibits oncogenic activity in several types of human cancers, including AML, but it remains unclear whether it regulates autophagy and chemoresistance in AML. We report here that cytarabine (Ara-C) treatment elevates DANCR expression in human AML cells. In addition, DANCR overexpression confers and its knockdown diminishes Ara-C resistance in human AML cells, suggesting that DANCR positively regulates AML chemoresistance to Ara-C. Moreover, DANCR promotes autophagy in Ara-C-treated human AML cells and acts as a sponge to decrease miR-20a-5p expression, thereby upregulating the expression of ATG16L1, a critical component of the autophagy machinery. Importantly, ATG16L1 silencing abrogates DANCR-promoted autophagy and markedly restores DANCR-conferred Ara-C resistance, suggesting that DANCR promotes MIR-874-3P/ATG16L1 axis-regulated autophagy to confer Ara-C resistance in human AML cells. Together, this study identifies DANCR as a positive regulator of Ara-C resistance in human AML cells, suggesting this lncRNA as a potential target for overcoming Ara-C resistance in AML chemotherapy.
Osteosarcoma (OS) is among the most frequently occurring bone tumors, particularly in children. Clinical treatment of OS is limited due to several factors including resistance to chemotherapy drugs and metastasis, and the underlying molecular mechanisms remain unclear. In the present study, tripartite motif containing 37 (TRIM37) expression levels were upregulated in tumor samples and associated with the development of drug resistance in OS. Furthermore, chemotherapy drug treatment (doxorubicin, cisplatin and methotrexate) induced TRIM37 expression in OS cells in vitro. TRIM37 mRNA and protein were upregulated in 41 pediatric osteosarcoma clinical specimens. To further elucidate the effect of TRIM37, gain and loss-of-function analysis was performed. Overexpression of TRIM37 induced cell proliferation and drug resistance ability of OS cells, whilst TRIM37 knockdown suppressed cell growth rate and restored chemosensitivity. TRIM37-regulated genes were subsequently analyzed by expression microarray and gene set enrichment analysis. Using the Wnt/β-catenin inhibitor XAV-939, the present study demonstrated that TRIM37-induced chemoresistance is partially dependent on the activation of the Wnt/β-catenin signaling pathway. Collectively, the results of the present study suggest that TRIM37 may have a key role in the development of OS and in the ability for the cells to acquire drug resistance, thus it may be a novel target for the treatment of OS.
PURPOSE Arsenic combined with all-trans retinoic acid (ATRA) is the standard of care for adult acute promyelocytic leukemia (APL). However, the safety and effectiveness of this treatment in pediatric patients with APL have not been reported on the basis of larger sample sizes. METHODS We conducted a multicenter trial at 38 hospitals in China. Patients with newly diagnosed APL were stratified into two risk groups according to baseline WBC count and FLT3-ITD mutation. ATRA plus arsenic trioxide or oral arsenic without chemotherapy were administered to the standard-risk group, whereas ATRA, arsenic trioxide, or oral arsenic plus reduced-dose anthracycline were administered to the high-risk group. Primary end points were event-free survival and overall survival at 2 years. RESULTS We enrolled 193 patients with APL. After a median follow-up of 28.9 months, the 2-year overall survival rate was 99% (95% CI, 97 to 100) in the standard-risk group and 95% (95% CI, 90 to 100) in the high-risk group ( P = .088). The 2-year event-free survival was 97% (95% CI, 93 to 100) in the standard-risk group and 90% (95% CI, 83 to 96) in the high-risk group ( P = .252). The plasma levels of arsenic were significantly elevated after treatment, with a stable effective level ranging from 42.9 to 63.2 ng/mL during treatment. In addition, plasma, urine, hair, and nail arsenic levels rapidly decreased to normal 6 months after the end of treatment. CONCLUSION Arsenic combined with ATRA is effective and safe in pediatric patients with APL, although long-term follow-up is still needed.
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