Correction: Cytosolic Hsp70 as a biomarker to predict clinical outcome in patients with glioblastoma.

[This corrects the article DOI: 10.1371/journal.pone.0221502.].

High expression of estrogen receptor alpha and aromatase in glial tumor cells is associated with gender-independent survival benefits in glioblastoma patients.

INTRODUCTION: Glioblastoma multiforme (GBM) is a highly malignant glial tumor, affecting men more often than women. The reason for this gender-specific predominance remains unclear, raising the question whether these effects are subject to hormonal control. The purpose of this study was to examine the expression of estrogen receptor alpha (ERα) and aromatase in human GBM tissue samples in relation to patient survival and furthermore to investigate the effect of standard chemotherapy in combination with estradiol treatment on glioblastoma tumor cell lines in vitro. METHODS: 60 tissue samples (31 male, 29 female) of GBM patients were analysed with immunohistochemistry for ERα and aromatase for survival analyses. The cell lines LN18 and LN229 were treated with 17ß-estradiol (E2) in different dosing regimens and the cell viability was measured with MTT assay. After estradiol pre-treatment Temozolomide was added and tested again. RESULTS: High expression of ERα and aromatase in the GBM tissue samples was associated with significantly longer survival times of GBM patients, regardless of gender and body-mass-index. The treatment with high concentrations of estradiol resulted in lower tumor cell viability, compared to control. The cells significantly showed a stronger sensitivity against Temozolomid (TMZ) after estradiol pre-treatment. CONCLUSION: ERα-expression of glial tumour cells seems to play an important prognostic role as a biomarker in GBM, as well as the expression of the enzyme Aromatase. The combined treatment of GBM with standard chemotherapy and estradiol may be beneficial to patient's survival.

Cytosolic Hsp70 as a biomarker to predict clinical outcome in patients with glioblastoma.

INTRODUCTION: The major stress-inducible heat shock protein 70 (Hsp70) is induced after different stress stimuli. In tumors, elevated intracellular Hsp70 levels were associated on the one hand with radio- and chemotherapy resistance and on the other hand with a favorable outcome for patients. This study was undertaken to investigate cytosolic Hsp70 (cHsp70) as a potential biomarker for progression free (PFS) and overall survival (OS) in patients with primary glioblastomas (GBM). METHODS: The cHsp70 expression in tumor tissue of 60 patients diagnosed with primary GBM was analyzed by immunohistochemistry. The cHsp70 expression was correlated to the PFS and OS of the patients. RESULTS: A high cHsp70 expression was associated with a prolonged PFS (hazard ratio = 0.374, p = 0.001) and OS (hazard ratio = 0.416, p = 0.014) in GBM patients treated according to the standard Stupp protocol with surgery, radiotherapy and temozolomide. CONCLUSIONS: These data suggest that the intracellular Hsp70 expression might serve as a prognostic marker in patients with primary GBM.

Pilot study to assess visualization and therapy of inflammatory mechanisms after vessel reopening in a mouse stroke model.

After reperfusion therapy in stroke patients secondary inflammatory processes may increase cerebral damage. In this pilot study, effects of anti-inflammatory therapy were assessed in a middle cerebral artery occlusion (MCAO) mouse model after reperfusion. 1 hour after MCAO, the artery was reopened and tacrolimus or NaCl were administered intra-arterially. Perfusion-weighted (PWI) and diffusion-weighted images (DWI) were obtained by MRI during MCAO. DWI, T2- and T1-weighted images with and without Bis-5HT-DTPA administration were obtained 24 hours after MCAO. Neutrophils, Myeloperoxidase-positive-(MPO+)-cells and microglia, including M1 and M2 phenotypes, were assessed immunohistochemically. Treatment with tacrolimus led to significantly smaller apparent diffusion coefficient (ADC) lesion volume within 24 hours (median -55.6mm3, range -81.3 to -3.6, vs. median 8.0 mm3, range 1.2 to 41.0; P = 0.008) and significantly lower enhancement of Bis-5-HT-DTPA (median signal intensity (SI) ratiocortex, median 92.0%, range 82.8% to 97.1%, vs. median 103.1%, range 98.7% to 104.6%; P = 0.008) compared to the NaCl group. Immunohistochemical analysis showed no significant differences between both groups. Intra-arterially administered anti-inflammatory agents after mechanical thrombectomy may improve treatment efficiency in stroke by reducing infarct volume size and MPO activity.

Temozolomide induces autophagy in primary and established glioblastoma cells in an EGFR independent manner.

Despite major contributions to the current molecular understanding of autophagy, a recycling process for intracellular components to maintain homeostatic balance, relatively little is known about the interacting networks. To address this issue, the current study investigated the role of autophagy in primary and established glioblastoma multiforme (GBM) cells and its interplay with the epidermal growth factor receptor (EGFR) and the standard chemotherapeutic agent temozolomide (TMZ). TMZ treatment leads to an upregulation of autophagy, predominantly in primary GBM cells. The interaction between EGFR and Beclin-1, an important protein in initiating autophagy, was assessed using a cancer cell line transfected with EGFRvIII, and by stimulation with EGF. The results of the current study suggest that Beclin-1 and EGFR do not interact directly in either primary or established GBM cells. To enable the limited efficacy of patient treatment strategies of GBM to potentially be enhanced through the application of autophagy regulators, the multiple cellular interactions of autophagy require further elucidation.