Temozolomide (TMZ) resistance is a major cause of recurrence and poor prognosis in glioblastoma (GBM). Recently, increasing evidences suggested that long noncoding RNAs (LncRNAs) modulate GBM biological processes, especially in resistance to chemotherapy, but their role in TMZ chemoresistance has not been fully illuminated. Here, we found that LncRNA SOX2OT was increased in TMZ-resistant cells and recurrent GBM patient samples, and abnormal expression was correlated with high risk of relapse and poor prognosis. Knockdown of SOX2OT suppressed cell proliferation, facilitated cell apoptosis, and enhanced TMZ sensitivity. In addition, we identified that SOX2OT regulated TMZ sensitivity by increasing SOX2 expression and further activating the Wnt5a/β-catenin signaling pathway in vitro and in vivo. Mechanistically, further investigation revealed that SOX2OT recruited ALKBH5, which binds with SOX2, demethylating the SOX2 transcript, leading to enhanced SOX2 expression. Together, these results demonstrated that LncRNA SOX2OT inhibited cell apoptosis, promoted cell proliferation, and TMZ resistance by upregulating SOX2 expression, which activated the Wnt5a/β-catenin signaling pathway. Our findings indicate that LncRNA SOX2OT may serve as a novel biomarker for GBM prognosis and act as a therapeutic target for TMZ treatment.

Astrocytes are critical for ischemic stroke, and understanding their role in mesenchymal stem cell (MSC)-mediated protection against ischemic injury is important. The paracrine capacity of MSCs has been proposed as the principal mechanism contributing to the protection and repair of brain tissue. In the present study, an in vitro oxygen-glucose deprivation (OGD) model was used to mimic ischemic injury. OGD-induced astrocytes were reperfused with MSC-conditioned medium (MSC-CM) or co-cultured with MSCs for 24 h to create an environment abundant in paracrine factors. The results indicated that both situations could protect astrocytes from apoptosis, increase cell metabolic activity, and reduce glial fibrillary acidic protein (GFAP) overexpression; however, the effects of co-culturing with MSCs were more positive. Paracrine factors suppressed the activation of p38 MAPK, JNK, and their downstream targets p53 and STAT1. Inhibition of p38 MAPK, JNK, p53, and STAT1 attenuated astrocyte injury and/or GFAP upregulation. Activation of p38 MAPK and JNK suppressed the beneficial effects of paracrine factors, resulting in decreased survival and GFAP overexpression. These results suggest that paracrine factors inhibit p38 MAPK and JNK, and most likely by regulating their downstream targets, p53 and STAT1, to promote astrocyte survival associated with GFAP downregulation after ischemic stroke in vitro.

Temozolomide (TMZ) and radiation therapy combination for glioblastoma (GB) patients has been considered as the most effective therapy after surgical procedure. However, the overall clinical prognosis remains unsatisfactory due to intrinsic or developing resistance to TMZ. Recently, increasing evidence suggested that long noncoding RNAs (lncRNAs) play a critical role in various biological processes of tumors, and have been implicated in resistance to various drugs. However, the role of lncRNAs in TMZ resistance is poorly understood. Here, we found that the expression of lncRNA AC003092.1 was markedly decreased in TMZ resistance (TR) of GB cells (U87TR and U251TR) compared with their parental cells (U87 and U251). In patients with glioma, low levels of lncRNA AC003092.1 were correlated with increased TMZ resistance, higher risk of relapse, and poor prognosis. Overexpression of lncRNA AC003092.1 enhances TMZ sensitivity, facilitates cell apoptosis, and inhibits cell proliferation in TMZ-resistant GB cells. In addition, we identified that lncRNA AC003092.1 regulates TMZ chemosensitivity through TFPI-2-mediated cell apoptosis in vitro and in vivo. Mechanistically, further investigation revealed that lncRNA AC003092.1 regulates TFPI-2 expression through miR-195 in GB. Taken together, these data suggest that lncRNA AC003092.1 could inhibit the function of miR-195 by acting as an endogenous CeRNA, leading to increased expression of TFPI-2; this promotes TMZ-induced apoptosis, thereby making GB cells more sensitive to TMZ. Our findings indicate that overexpression of lncRNA AC003092.1 may be a potential therapy to overcome TMZ resistance in GB patients.

Resistance to temolozomide (TMZ), the standard chemotherapy agent for treating glioblastomas (GBM), is a major clinical problem for patients with GBM. Recently, long noncoding RNAs (lncRNAs) have been implicated in chemotherapy resistance in various cancers. In this study, we found that the level of the lncRNA RP11-838N2.4 was lower in TMZ-resistant GBM cells (U87TR, U251TR) compared to the parental, non-resistant GBM cells (U87, U251). In GBM patients, the decreased level of lncRNA RP11-838N2.4 correlated with higher risk of GBM relapse, as well as shorter postoperative survival times. We further found that lncRNA RP11-838N2.4 could enhances the cytotoxic effects of temozolomide to GBM cells both in vivo and in vitro. Moreover, lncRNA RP11-838N2.4 acts as an endogenous sponge, suppressing the function of miR-10a through conserved sequences and increasing the expression of EphA8 that enhanced the rate of cell apoptosis, thereby intensified sensitivity of GBM cells to TMZ. Additionally, lncRNA RP11-838N2.4 inhibited the activity of transforming growth factor-β (TGF-β) independent of miR-10a. Finally, Characterization of lncRNA RP11-838N2.4 could contribute to strategies for enhancing the efficacy of TMZ.

Limited benefits and clinical utility of temozolomide (TMZ) for glioblastoma (GB) are frequently compromised by the development of acquired drug resistance. Overcoming TMZ resistance and uncovering the underlying mechanisms are challenges faced during GB chemotherapy. In this study, we reported that connective tissue growth factor (CTGF) was associated with GB chemoresistance and significantly upregulated in TMZ-treated GB cells. CTGF knockdown promoted TMZ-induced cell apoptosis and enhanced chemosensitivity, whereas its overexpression markedly conferred TMZ resistance in vitro and in vivo. Moreover, CTGF promoted TMZ resistance through stem-like properties acquisition and CD44 interference reversed the CTGF-induced TMZ resistance. Mechanistically, further investigation revealed that the TMZ-induced CTGF upregulation was tissue growth factor (TGF-β) dependent, and regulated by TGF-β1 activation through Smad and ERK1/2 signaling. Together, our results suggest a pivotal role of CTGF-mediated TMZ resistance through TGF-β1-dependent activation of Smad/ERK signaling pathways. These data provide us insights for identifying potential targets that are beneficial for overcoming TMZ resistance in GB.

Temozolomide (TMZ) is an alkylating chemotherapeutic agent widely used in anti-glioma treatment. However, acquired TMZ resistance represents a major clinical challenge that leads to tumor relapse or progress. This study investigated the genomic profiles including long non-coding RNA (lncRNA) and mRNA expression associated with acquired TMZ resistance in glioblastoma (GBM) cells in vitro. The TMZ-resistant (TR) of GBM sub-cell lines were established through repetitive exposure to increasing TMZ concentrations in vitro. The differentially expressed lncRNAs and mRNAs between the parental U87 and U87TR cells were detected by human lncRNA microarray method. In this study, we identified 2,692 distinct lncRNAs demonstrating >2-fold differential expression with 1,383 lncRNAs upregulated and 1,309 lncRNAs downregulated. Moreover, 4,886 differential mRNAs displayed 2,933 mRNAs upregulated and 1,953 mRNAs downregulated. Further lncRNA classification and subgroup analysis revealed the potential functions of the lncRNA-mRNA relationship associated with the acquired TMZ resistance. Gene ontology and pathway analysis on mRNAs showed significant biological regulatory genes and pathways involved in acquired TMZ resistance. Moreover, we found the ECM-receptor interaction pathway was significantly downregulated and ECM related collagen I, fibronectin, laminin and CD44 were closely associated with the TR phenotype in vitro. Our findings indicate that the dysregulated lncRNAs and mRNAs identified in this work may provide novel targets for overcoming acquired TMZ resistance in GBM chemotherapy.

Hydroxyapatite (HAp) particles with different morphology but similar physicochemical properties were prepared by a novel and facile route. The interaction between the particles with BMSCs was investigated, and results revealed that particles’ shape has a strong influence on cellular behavior.

Excessive inflammatory response may delay the regeneration and damage the normal muscle fibers upon myoinjury. It would be important to be able to attenuate the inflammatory response and decrease inflammatory cells infiltration in order to improve muscle regeneration formation, resulting in better muscle functional recovery after myoinjury. This study was undertaken to explore the role of Nitric oxide (NO) during skeletal muscle inflammatory process, using a mouse model of Notexin induced myoinjury. Intramuscular injection (tibialis anterior, TA) of Notexin was performed for preparing mice myoinjury. NO synthase inhibitor (L-NAME) or NO donor (SNP) was intraperitoneally injected into model mice. On day 4 and 7 post-injury, expression of muscle-autoantigens and toll-like receptors (TLRs) was evaluated from muscle tissue by qRT-PCR and Western Blot; the intramuscular infiltration of monocytes/macrophage (CD11b+ or F4/80+ cells), CD8+ T cell (CD3ε+CD8α+), apoptotic cell (CD11b+caspase3+), and MHC-I molecule H-2Kb-expressing myofibers in damaged muscle were assessed by imunoflourecence analysis; the mRNAs expression of cytokines and chemokines associated with the preferential biological role during the muscle damage-induced inflammation response, were assessed by qRT-PCR. We detected the reduced monocytes/macrophages infiltration, and increased apoptotic cells in the damaged muscle treated with SNP comparing to untreatment. As well, SNP treatment down-regulated mRNA and protein levels of muscle autoantigens, TLR3, and mRNA levels of TNF-α, IL-6, MCP-1, MCP-3, and MIP-1α in damaged muscle. On the contrary, L-NAME induced more severe intramuscular infiltration of inflammatory cells, and mRNA level elevation of the above inflammatory mediators. Notably, we observed an increased number of MHC-I (H2-Kb) positive new myofibers, and of the infiltrated CD8+ T cells in damaged muscle at the day 7 after L-NAME treatment. The result herein shows that, NO can act as an endogenous anti-inflammatory molecule during the ongoing muscle inflammation. Our finding may provide new insight to optimize NO-based therapies for improving muscle regeneration after myoinjury.