Juxiang Chen

MicroRNA-21 targets LRRFIP1 and contributes to VM-26 resistance in glioblastoma multiforme.

MicroRNAs control a wide array of biological processes including cell differentiation, proliferation, and apoptosis whose dysregulation is a hallmark of cancer. MicroRNA-21 (miR-21) is overexpressed in many cancers including glioblastoma and contributes to tumor resistance to chemotherapy. We investigated whether miR-21 mediated chemoresistance to the chemotherapeutic agent VM-26 in glioblastoma cells and sought to identify the candidate target genes for miR-21 by gene expression profiling. Here we report that miR-21 was involved in mediating chemoresistance to VM-26 in glioblastoma cells. Suppression of miR-21 by specific antisense oligonucleotides in glioblastoma cell U373 MG led to enhanced cytotoxicities of VM-26 against U373 MG cells. We further identified and validated LRRFIP1, whose product is an inhibitor of NF-kappaB signaling, as a direct target gene of miR-21. Our findings suggest that miR-21 represents a promising target for therapeutic manipulation to increase the efficacy of chemotherapeutic agents in treating glioblastoma, a highly lethal type of cancer.

Allergy and risk of glioma: a meta-analysis.

We evaluated the association between allergic conditions and the risk of glioma in case–control and cohort studies published so far on this issue. A total of 12 studies (10 case–control and 2 cohort studies) were included in the analysis, involving 61 090 participants, of whom 6408 had glioma. When compared with non‐allergic conditions, the pooled odds ratio (OR) with any allergic conditions for glioma was 0.60 (95% CI: 0.52–0.69, P < 0.001), suggesting a significant negative association (protective effect) between allergy and glioma. Subgroup analysis showed that the ORs were 0.70 (95% CI: 0.62–0.79, P < 0.001), 0.69 (95% CI: 0.62–0.78, P < 0.001), and 0.78 (95% CI: 0.70–0.87, P < 0.001) for asthma, eczema, and hay fever, respectively. The significant association remained even after excluding the bias of proxy reporting (OR = 0.61; 95% CI: 0.50–0.75, P < 0.001). We conclude that allergic conditions may significantly reduce the risk of glioma.

Risk of cardiac dysfunction with trastuzumab in breast cancer patients: A meta-analysis

BACKGROUND Trastuzumab is used widely for the treatment of early and advanced breast cancer. However, concerns have arisen regarding its cardiac toxicity. We did a systematic review and meta-analysis of published randomized controlled trials (RCTs) to assess the overall risk of cardiac dysfunction associated with trastuzumab treatment. METHODS We searched PubMed and Web of Science (January 1966-July 2009) and American Society of Clinical Oncology conferences held (January 2000-July 2009) for relevant articles and abstracts. Summary incidence rates, relative risks (RRs), and 95% confident intervals (CIs) were calculated using a fixed-effects or random-effects model. RESULTS 11,882 patients from 10 RCTs were included for analysis. The incidences of LVEF decrease and congestive heart failure (CHF) were 7.5% (95% CI 4.2-13.1) and 1.9% (95% CI 1.0-3.8) among patients receiving trastuzumab. Trastuzumab significantly increased the risk of LVEF decrease (RR = 2.13, 95% CI, 1.31-3.49; p = 0.003). In addition, it significantly increased the risk of CHF (RR = 4.19, 95% CI 2.73-6.42; p < 0.00001). The increased risk of CHF was observed in patients with early stage (RR = 4.05, 95% CI 2.49-6.58; p < 0.00001) as well as metastatic disease (RR = 4.75, 95% CI 1.93-11.71; p = 0.0007). Furthermore, trastuzumab significantly increased the risk of CHF (RR = 4.27, 95% CI 2.75-6.61, p < 0.00001) in patients receiving anthracycline-based chemotherapy, but not in patients receiving non-anthracycline chemotherapy (RR = 2.42, 95% CI 0.36-16.19, p = 0.36). CONCLUSION The addition of trastuzumab to anthracycline-based chemotherapy significantly increase the risk of cardiac dysfunction in breast cancer patients. Further studies are recommended for non-anthracycline chemotherapy.

Discovery and analysis of hepatocellular carcinoma genes using cDNA microarrays.

Abstract Purpose. Microarray analysis on a genomic scale was used to profile changes in gene expression accompanying hepatocellular carcinoma. Methods. Gene expression profiles of liver tissues from twelve hepatocellular carcinoma samples relative to the gene expression profile of the normal liver tissue were analyzed using 4096 chips and 12800 chips. The results of microarray experiments were verified by the Northern blot technique. Results. A group of 1,820 genes with altered expression were identified in more than 50% of the patients examined. This highly concordant expression profile included human genes encoding proteins involved in the function of peroxisomes, serum control, polycyclic aromatic hydrocarbon carcinogenesis, cell growth and differentiation, metastasis, the function of the immune system, apoptosis, and remodeling of the cytoskeleton. Conclusions. The newly identified genes afford a quantitative view of the changes that accompany liver cancer at the genomic level, enable deeper insights into the molecular basis of disease, and provide an extensive list of potential early-onset molecular markers for improved diagnosis.

Effects of bevacizumab plus irinotecan on response and survival in patients with recurrent malignant glioma: a systematic review and survival-gain analysis

BackgroundThe combination of bevacizumab and irinotecan is a new chemotherapy protocol increasingly used for recurrent malignant glioma. Results from phase II trials suggest this drug combination is beneficial to patients, but no conclusive comparisons between this and other treatment protocols have been published.MethodsWe performed a systematic review and survival gain analysis of phase II studies to evaluate the efficacy and safety of bevacizumab plus irinotecan treatment. To do this, we utilized a preexisting database from which the mean overall survival and response rate of patients could be predicted. Survival gain, which characterized the influence of treatment, was defined as the difference between observed and predicted mean overall survival. Response gain was calculated similarly.Results741 cohorts were enrolled in the database. Among them, 282 cohorts were based on recurrent adult HGG, mean reported median overall survival was 10.96 ± 8.4 months, and mean response rate was 18.9% ± 20.5. We found that compared with other treatment protocols, bevacizumab plus irinotecan largely improved response rates (P = 0.00002) and had a possible moderate effect on overall survival time (P = 0.024). Hemorrhage, thromboembolic complications, and gastrointestinal toxicities were the most frequently reported side effects.ConclusionThe combination of bevacizumab and irinotecan might improve outcome in patients with recurrent malignant glioma. Randomized controlled trials are recommended to evaluate this treatment protocol and the additional value of irinotecan.

The challenges and the promise of molecular targeted therapy in malignant gliomas.

Malignant gliomas are the most common malignant primary brain tumors and one of the most challenging forms of cancers to treat. Despite advances in conventional treatment, the outcome for patients remains almost universally fatal. This poor prognosis is due to therapeutic resistance and tumor recurrence after surgical removal. However, over the past decade, molecular targeted therapy has held the promise of transforming the care of malignant glioma patients. Significant progress in understanding the molecular pathology of gliomagenesis and maintenance of the malignant phenotypes will open opportunities to rationally develop new molecular targeted therapy options. Recently, therapeutic strategies have focused on targeting pro-growth signaling mediated by receptor tyrosine kinase/RAS/phosphatidylinositol 3-kinase pathway, proangiogenic pathways, and several other vital intracellular signaling networks, such as proteasome and histone deacetylase. However, several factors such as cross-talk between the altered pathways, intratumoral molecular heterogeneity, and therapeutic resistance of glioma stem cells (GSCs) have limited the activity of single agents. Efforts are ongoing to study in depth the complex molecular biology of glioma, develop novel regimens targeting GSCs, and identify biomarkers to stratify patients with the individualized molecular targeted therapy. Here, we review the molecular alterations relevant to the pathology of malignant glioma, review current advances in clinical targeted trials, and discuss the challenges, controversies, and future directions of molecular targeted therapy.

MicroRNA-326 functions as a tumor suppressor in glioma by targeting the Nin one binding protein (NOB1).

Malignant glioma is the most common type of primary brain tumor in adults, characterized by rapid tumor growth and infiltration of tumor cells throughout the brain. Alterations in the activity of the 26S proteasome have been associated with malignant glioma cells, although the specific defects have not been identified. Recently, microRNA-326 (miR-326) was shown to play an important role in glioblastoma and breast cancer, but the underlying molecular mechanisms remain unclear. In the present study, the human Nin one binding protein (NOB1) was identified as a direct target of miR-326 and a potential oncogene in human glioma. Similar to NOB1 silencing by shRNA, overexpression of miR-326 in human glioma cell lines (A172 and U373) caused cell cycle arrest at the G1 phase, delayed cell proliferation and enhanced apoptosis. MiR-326 inhibited colony formation in soft agar and decreased growth of a xenograft tumor model, suggesting that miR-326 and NOB1 are required for tumorigenesis in vitro and in vivo. Furthermore, these processes were shown to involve the MAPK pathway. NOB1 overexpression in human glioma samples was detected by Affymetrix array analysis, and NOB1 mRNA and protein levels were shown to be increased in high-grade glioma compared to low-grade glioma and normal brain tissue. Furthermore, high levels of NOB1 were associated with unfavorable prognosis of glioma patients. Taken together, these results indicate that miR-326 and NOB1 may play an important role in the development of glioma.

Prognostic Influence and Magnetic Resonance Imaging Findings in Paroxysmal Sympathetic Hyperactivity after Severe Traumatic Brain Injury

Paroxysmal sympathetic hyperactivity (PSH) is a clinical syndrome affecting a subgroup of survivors of severe brain injury. In this study, the prevalence, magnetic resonance imaging (MRI) presentation, influence on the clinical course in the intensive care unit (ICU), and effect on neurological recovery of PSH were prospectively surveyed in 87 patients with severe traumatic brain injury (TBI). Cranial MRI was performed during the first 30 days after injury. The outcome was assessed according to the Glasgow Outcome Scale (GOS). PSH occurred in 18.4% of patients, with a greater incidence among younger patients and those with lower Glasgow Coma Scale (GCS) scores. Patients with PSH had more deep lesions as shown on cranial MRI, significantly longer ICU stays, and worse outcomes. PSH was shown to be common among patients with severe TBI who also had deep intraparenchymal lesions. The mechanism by which PSH influences patient outcomes has yet to be defined, but we believe that it may be mediated by diencephalic-mesencephalic dysfunction or disconnection.

The efficacy of temozolomide for recurrent glioblastoma multiforme

The efficacy of temozolomide (TMZ) in recurrent glioblastoma multiforme (GBM) has been evaluated by several clinical trials. A meta‐analysis to assess the overall efficacy of TMZ in the treatment of recurrent GBM was carried out by the authors.

RLIP76 is overexpressed in human glioblastomas and is required for proliferation, tumorigenesis and suppression of apoptosis

The guanosine triphosphatase-activating protein RLIP76 is overexpressed in many malignant tumor cells, but it is unclear if RLIP76 overexpression contributes to the high proliferative potential of glioma cells. We demonstrate that RLIP76 messenger RNA and protein expression are positively correlated with glioma grade and that higher RLIP76 expression correlates with shorter patient survival. Immunohistochemical staining revealed that RLIP76 expression was positively correlated with the expression of Ki-67, a biomarker for cell proliferation. Inhibition of RLIP76 expression in U87 and U251 glioma cell lines by stable transfection of a targeted siRNA suppressed anchorage-independent growth and enhanced apoptosis in vitro. Conversely, overexpression of RLIP76 in SW1088 and U251 cell lines enhanced proliferation and reduced apoptosis. Inhibition of RLIP76 in U251 cells also significantly suppressed tumorigenicity and induced apoptosis in an endotopic xenograft mouse model. Moreover, we demonstrate that knockdown of RLIP76 increases apoptosis in different human gliomas independently of p53 status. In addition, a constitutively active Rac1 reversed both the suppression of proliferation and the promotion of apoptosis induced by the RLIP76-targeted siRNA, indicating that RLIP76 is an upstream activator of Rac1. Rac1-mediated suppression of apoptosis and promotion of proliferation were dependent on intact c-jun N-terminal kinase (JNK) signaling. Furthermore, we demonstrate that RLIP76 promotes proliferation and suppresses glioma cell apoptosis through a mechanism independent of Rho-selective GTPase-activating protein. Instead, we found that the adenosine triphosphatase function of Rlip76 modulates Rac1 activity by regulating Rac1 protein ubiquitylation and degradation. These data demonstrate that RLIP76 may suppress apoptosis and promote the proliferation of glioma cells by direct adenosine triphosphate-dependent xenobiotic transport and by activating the Rac1-JNK signaling pathway. Inhibition of RLIP76 signaling is a potential treatment for malignant glioma.