Cheng Cheng Guo

Circulating miR‐221 directly amplified from plasma is a potential diagnostic and prognostic marker of colorectal cancer and is correlated with p53 expression

Background and Aim:  Circulating miRNAs exist in serum and plasma and they can be used as a potential noninvasive molecular marker for colorectal cancer (CRC) diagnosis. The present study was to test the availability of direct amplification of miRNAs from plasma without RNA extraction, and to evaluate its clinical application value in CRC.

Enhanced MGMT expression contributes to temozolomide resistance in glioma stem-like cells

O6-methylguanine DNA methyltransferase (MGMT) can remove DNA alkylation adducts, thereby repairing damaged DNA and contributing to the drug resistance of gliomas to alkylating agents. In addition, glioma stem-like cells (GSCs) have been demonstrated to be involved in the recurrence and treatment resistance of gliomas. In this study, we aimed to investigate MGMT expression and regulatory mechanisms in GSCs and the association of MGMT with temozolomide (TMZ) sensitivity. GSCs were enriched from one MGMT-positive cell line (SF-767) and 7 MGMT-negative cell lines (U251, SKMG-4, SKMG-1, SF295, U87, MGR1, and MGR2) through serum-free clone culture. GSCs from the U251G, SKMG-4G, SF295G, and SKMG-1G cell lines became MGMT-positive, but those from the U87G, MGR1G, and MGR2G cell lines remained MGMT-negative. However, all the GSCs and their parental glioma cell lines were positive for nuclear factor-κB (NF-κB). In addition, GSCs were more resistant to TMZ than their parental glioma cell lines (P < 0.05). However, there was no significant difference in the 50% inhibition concentration (IC50) of TMZ between MGMT-positive and MGMT-negative GSCs (P > 0.05). When we treated the MGMT-positive GSCs with TMZ plus MG-132 (an NF-κB inhibitor), the antitumor activity was significantly enhanced compared to that of GSCs treated with TMZ alone (P < 0.05). Furthermore, we found that MGMT expression decreased through the down-regulation of NF-κB expression by MG-132. Our results show that MG-132 may inhibit NF-κB expression and further decrease MGMT expression, resulting in a synergistic effect on MGMT-positive GSCs. These results indicate that enhanced MGMT expression contributes to TMZ resistance in MGMT-positive GSCs.

Triptolide Synergistically Enhances Temozolomide-Induced Apoptosis and Potentiates Inhibition of NF-κB Signaling in Glioma Initiating Cells

Glioblastoma multiforme (GBM) is a lethal solid cancer in adults. Temozolomide (TMZ) is a first-line chemotherapeutic agent but the efficacy is limited by intrinsic and acquired resistance in GBM. Triptolide (TPL), a derivative from traditional Chinese medicine, demonstrated anti-tumor activity. In this study, we explored the interaction of TPL and TMZ in glioma-initiating cells (GICs) and the potential mechanism. A GIC line (GIC-1) was successfully established. Cell viability of GIC-1 after treatment was measured using a CCK-8 assay. The interaction between TPL and TMZ was calculated from Chou-Talalay equations and isobologram. Self-renewal was evaluated with tumor sphere formation assay. Apoptosis was assessed with flow cytometry and western blot. Luciferase assay was employed to measure NF-κB transcriptional activity. The expression of NF-κB downstream genes, NF-κB nuclear translocalization and phoshorylation of IκBα and p65 were evaluated using western blot. We found that GIC-1 cells were resistant to TMZ, with the expected IC50 of 705.7 μmol/L. Co-treatment with TPL yielded a more than three-fold dose reduction of TMZ. TPL significantly increased the percentage of apoptotic cells and suppressed the tumor sphere formation when combined with TMZ. Phosphorylation of IκBα and p65 coupled with NF-κB nuclear translocalization were notably inhibited after a combined treatment. Co-incubation synergistically repressed NF-κB transcriptional activity and downstream gene expression. TPL sensitizes GICs to TMZ by synergistically enhancing apoptosis, which is likely resulting from the augmented repression of NF-κB signaling. TPL is therefore a potential chemosensitizer in the treatment of GBM.

Interferon-α/β enhances temozolomide activity against MGMT-positive glioma stem-like cells

Glioma is one of the most common primary tumors of the central nervous system in adults. Glioblastoma (GBM) is the most lethal type of glioma, whose 5-year survival is 9.8% at best. Glioma stem-like cells (GSCs) play an important role in recurrence and treatment resistance. MGMT is a DNA repair protein that removes DNA adducts and therefore attenuates treatment efficiency. It has been reported that interferon-α/β (IFN-α/β) downregulates the level of MGMT and sensitizes glioma cells to temozolomide. In the present study, we assessed whether IFN-α/β is able to sensitize GSCs to temozolomide by modulating MGMT expression. Upon the treatment of IFN-α/β, the efficacy of temozolomide against MGMT‑positive GSCs was markedly enhanced by combination treatment with IFN-α/β when compared with the temozolomide single agent group, and MGMT expression was markedly decreased at the same time. Further mechanistic study showed that IFN-α/β suppressed the NF-κB activity, which further mediated the sensitization of MGMT‑positive GSCs to temozolomide. Our data therefore demonstrated that the application of IFN-α/β is a promising agent with which to enhance temozolomide efficiency and reduce drug resistance, and our findings shed light on improving clinical outcomes and prolonging the survival of patients with malignant gliomas.

Safety evaluation of high-dose BCNU-loaded biodegradable implants in Chinese patients with recurrent malignant gliomas

OBJECTIVES Malignant gliomas are common primary brain tumors with dismal prognosis. The blood-brain barrier and unacceptable systemic toxicity limit the employment of chemotherapeutic agents. BCNU-impregnated biodegradable polymers (Gliadel®) have been demonstrated to prolong the survival of patients with malignant gliomas. Until now, no biodegradable drug delivery system has been commercially available in China. In the present study, we evaluated the safety of implants with high-dose BCNU in Chinese patients with recurrent malignant gliomas. PATIENTS AND METHODS Adults with supratentorial recurrent malignant glioma were eligible. High-dose BCNU-loaded PLGA implants (20mg of BCNU in each implant) were placed in the debulking cavity. The implants were investigated by a classical 3+3 design. Four levels of BCNU, up to 12 implants, were evaluated. Pharmacokinetic sampling was performed. The toxicity of the implants and the survival of patients were recorded. RESULTS Fifteen recurrent patients were enrolled with 12 glioblastomas and 3 anaplastic gliomas. Among 15 patients, 3 were treated with 3 implants (60 mg of BCNU), 3 with 6 implants (120 mg), 3 with 9 implants (180 mg) and 6 with 12 implants (240 mg). No dose-limiting toxicity was observed in the cohort of patients. Subgaleal effusion was the most common adverse event, presenting in 7 patients (46.7%). The median overall survival (OS) was 322 days (95% CI, 173-471 days). The 6-month, 1-year and 2-year survival rates were 66.7%, 40% and 13.3%, respectively. CONCLUSIONS The high-dose BCNU-loaded PLGA implants were safe for Chinese patients with recurrent malignant gliomas and further investigation for efficacy is warranted.

β-Elemene Selectively Inhibits the Proliferation of Glioma Stem-Like Cells Through the Downregulation of Notch1

Glioma is the most frequent primary central nervous system tumor. Although the current first‐line medicine, temozolomide (TMZ), promotes patient survival, drug resistance develops easily. Thus, it is important to investigate novel therapeutic reagents to solidify the treatment effect. β‐Elemene (bELE) is a compound from a Chinese herb whose anticancer effect has been shown in various types of cancer. However, its role in the inhibition of glioma stem‐like cells (GSLCs) has not yet been reported. We studied both the in vitro and the in vivo inhibitory effect of bELE and TMZ in GSLCs and parental cells and their combined effects. The molecular mechanisms were also investigated. We also optimized the delivery methods of bELE. We found that bELE selectively inhibits the proliferation and sphere formation of GSLCs, other than parental glioma cells, and TMZ exerts its effects on parental cells instead of GSLCs. The in vivo data confirmed that the combination of bELE and TMZ worked better in the xenografts of GSLCs, mimicking the situation of tumorigenesis of human cancer. Notch1 was downregulated with bELE treatment. Our data also demonstrated that the continuous administration of bELE produces an ideal effect to control tumor progression. Our findings have demonstrated, for the first time, that bELE could compensate for TMZ to kill both GSLCs and nonstem‐like cancer cells, probably improving the prognosis of glioma patients tremendously. Notch1 might be a downstream target of bELE. Therefore, our data shed light on improving the outcomes of glioma patients by combining bELE and TMZ. Stem Cells Translational Medicine 2017;6:830–839

Cyclosporine, prednisone, and high-dose immunoglobulin treatment of angioimmunoblastic T-cell lymphoma refractory to prior CHOP or CHOP-like regimen.

Angioimmunoblastic T-cell lymphoma (AITL) is a rare, distinct subtype of peripheral T-cell lymphoma, possessing an aggressive course and poor prognosis with no standard therapy. Twelve patients who have failed at least two initial CHOP or CHOP-like regimens were enrolled in this study and treated with individualized cyclosporine (CsA), prednisone (PDN), and monthly, high-dose intravenous immunoglobulin (HDIVIG). The dose of CsA was adjusted individually based on the blood trough concentration of CsA and renal function. All patients were examined for response, toxicity and survival. The most significant toxicities (≥ grade 2) were infection (16.7%), renal insufficiency (8.3%), hypertension (8.3%), diabetes (8.3%) and insomnia (16.7%). Discontinuation of treatment occurred in one patient (8.3%) due to grade 3 renal toxicity and subsequent grade 4 pulmonary infection. Treatment-related death was not observed. The overall response rate was 75.0% (complete response, 33.3%; partial response, 41.7%). With a median follow-up of 25.5 months, the median duration of response was 20 months (range, 12 to 49 months) and the median progression-free survival (PFS) was 25.5 months (range, 10 to 56 months). The 2-year PFS rate was 81.5%. Our findings indicate the combination of CsA, PDN and HDIVIG is an effective salvage regimen for refractory or relapsed AITL with predictable and manageable toxicity.

Evaluation of cumulative prognostic score based on pretreatment plasma fibrinogen and serum albumin levels in patients with newly diagnosed high-grade gliomas

This retrospective study was designed to determine the prognostic value of a cumulative score (FA score) based on pretreatment plasma fibrinogen and serum albumin levels for 326 patients newly diagnosed high-grade glioma (HGG). Receiver operating characteristic (ROC) curve analysis was performed to determine the optimal cut-off values. Univariate and multivariate analysis were performed to evaluate the independent prognostic value of the FA scores associated with overall survival (OS) and progression-free survival (PFS). The optimal cut-off values were 2.815 g/L for fibrinogen and 43.65 g/L for albumin. PFS and OS were significantly worse for patients with higher FA scores. Patients with elevated fibrinogen level and decreased albumin levels had 3.00-fold higher risk of tumor progression and had a 3.23-fold higher risk of death compared with those with normal values. Multivariate analysis demonstrated FA score was an independent predictive factor for PFS and OS. Moreover, PFS and OS were better for the patients with lower FA score, either in patients with grade III or IV gliomas. These findings indicated that the pretreatment FA score could serve as a simple and noninvasive marker to predict the prognosis of patients with HGG.

Treatment of primary intracranial germ cell tumors: Singlecenter experience with 42 clinically diagnosed cases

Background and Objective Primary intracranial germ cell tumors (GCTs) are a class of heterogeneous tumors. Surgery can quickly relieve tumor compression and provide histological diagnosis. It is very difficult to treat some patients who are unable to be pathologically diagnosed. We aimed to analyze clinically diagnosed GCTs patients. Methods Patients clinically diagnosed as primary intracranial GCTs were included in this study. Results From 2002 to 2015, 42 patients clinically diagnosed with primary intracranial GCTs received chemotherapy and/or radiotherapy. Patients were assigned to diagnostic chemotherapy group (25 cases), diagnostic radiotherapy group (5 cases) and gamma knife radiosurgery group (12 cases) based on their initial anti-tumor therapy. The 5-year survival rates were 85.8%, 75.0% and 63.6%, respectively. There were no statistically significant difference (p value = 0.44). Patients were assigned to the group (30 cases) with secretory tumors and the group (12 cases) with non-secretory tumors based on their levels of tumor makers. The 5- year survival rates were 80.7% and 68.6%, respectively. There were no statistically significant difference (p value = 0.49).The major adverse reactions were grade III - IV bone marrow suppression with an incidence of 35.2% and grade II- III nausea/vomiting with an incidence of 45.8%. Conclusion Surgical removal of tumor or biopsy is recognized as the most accurate method to determine the pathological property of tumor. But for some patients who can not be pathologically diagnosed, they can receive comprehensive treatments such as chemotherapy combined with radiotherapy, and some of them can still have good responses.

High MMP‑26 expression in glioma is correlated with poor clinical outcome of patients

To date the management of glioma remains a great challenge in cancer therapy worldwide. The identification of novel diagnostic and therapeutic methods is required. Although there is data indicating that matrix metalloproteinase (MMP)-26 serves an important role in many human cancer types, its clinical significance in glioma remains uncertain. The present study aimed to evaluate MMP-26 expression in human astrocytic glioma specimens, and investigate its role and significance in the progression of astrocytic glioma. Immunohistochemistry was performed to assess MMP-26 expression in astrocytic glioma tissues. The levels of MMP-26 expression and its relevance to the clinicopathological features and prognostic factors in patients with astrocytic glioma patients were then investigated. The results demonstrated that MMP-26 expression was significantly assocaited with the World Health Organization grade (P<0.05). Additionally, it was identified that MMP-26 expression was an effective predictor of the overall survival of patients with astrocytic glioma (P<0.05). Analyses of univariate and multivariate Cox regression confirmed that MMP-26 expression was an independent factor for evaluating the prognosis of astrocytic glioma patients (P<0.05). The current results support that MMP-26 may be a novel indicator of diagnosis and an independent factor for evaluating prognosis in patients with glioma.