Krüppel-like factor 8 (KLF8) is expressed in gliomas of different WHO grades and is essential for tumor cell proliferation.

Krüppel-like factor 8 (KLF8) has only recently been identified to be involved in tumor cell proliferation and invasion of several different tumor entities like renal cell carcinoma, hepatocellular carcinoma and breast cancer. In the present study, we show for the first time the expression of KLF8 in gliomas of different WHO grades and its functional impact on glioma cell proliferation. In order to get information about KLF8-mRNA regulation qPCR was performed and did not reveal any significant difference in samples (n = 10 each) of non-neoplastic brain (NNB), low-grade gliomas (LGG, WHO°II) and glioblastomas (GBM, WHO°IV). Immunohistochemistry of tissue samples (n = 7 LGG, 11 AA and 12 GBM) did not show any significant difference in the fraction of KLF8-immunopositive cells of all analyzed cells in LGG (87%), AA (80%) or GBM (89%). Tissue samples from cerebral breast cancer metastasis, meningiomas but also non-neoplastic brain demonstrated comparable relative cell counts as well. Moreover, there was no correlation between KLF8 expression and the expression pattern of the assumed proliferation marker Ki67, which showed high variability between different tumor grade (9% (LGG), 6% (AA) and 15% (GBM) of Ki67-immunopositive cells). Densitometric analysis of Western blotting revealed that the relative amount of KLF8-protein did also not differ between the highly aggressive and proliferative GBM (1.05) compared to LGG (0.93; p<0.05, studens t-test). As demonstrated for some other non-glial cancer entities, KLF8-knockdown by shRNA in U87-MG cells confirmed its functional relevance, leading to an almost complete loss of tumor cell proliferation. Selective blocking of KLF8 might represent a novel anti-proliferative treatment strategy for malignant gliomas. Yet, its simultaneous expression in non-proliferating tissues could hamper this approach

Glucocorticoid (dexamethasone)-induced metabolome changes in healthy males suggest prediction of response and side effects

Glucocorticoids are indispensable anti-inflammatory and decongestant drugs with high prevalence of use at (similar to)0.9% of the adult population. Better holistic insights into glucocorticoid-induced changes are crucial for effective use as concurrent medication and management of adverse effects. The profiles of 214 metabolites from plasma of 20 male healthy volunteers were recorded prior to and after ingestion of a single dose of 4 mg dexamethasone (+20 mg pantoprazole). Samples were drawn at three predefined time points per day: seven untreated (day 1 midday - day 3 midday) and four treated (day 3 evening - day 4 evening) per volunteer. Statistical analysis revealed tremendous impact of dexamethasone on the metabolome with 150 of 214 metabolites being significantly deregulated on at least one time point after treatment (ANOVA, Benjamini-Hochberg corrected, q < 0.05). Inter-person variability was high and remained uninfluenced by treatment. The clearly visible circadian rhythm prior to treatment was almost completely suppressed and deregulated by dexamethasone. The results draw a holistic picture of the severe metabolic deregulation induced by single-dose, short-term glucocorticoid application. The observed metabolic changes suggest a potential for early detection of severe side effects, raising hope for personalized early countermeasures increasing quality of life and reducing health care costs

KLF8 and Ki67 expression in non-CNS tumors.

<p>KLF8 (A, C, E) and Ki67 (B, D, F) protein expression was analyzed in some additional tissue samples of breast cancer metastasis (A, B), meningioma (C, D) and non-neoplastic brain (E, F). All tissue samples analyzed confirmed ubiquitous expression of this transcription molecule, irrespective of the assumed proliferation rate.</p

Western blot and densitometric analysis of KLF8 Western blots in gliomas.

<p>Western blot was performed for samples from gliomas of different WHO grades (GBM °IV, LGG °II) as well as non-neoplastic brain (NNB) (A). Densitometric analysis of the Western blot revealed no significant difference in expression of the transcription factor KLF8 in GBM compared to LGG and non-neoplastic brain samples. Protein expression was normalized to the house-keeping gene β-actin (set as 1.0, B).</p

Quantitative PCR.

<p>Samples of low-grade gliomas LGG and GBM (n = 10 each) were analyzed for KLF8-mRNA regulation. Compared to non-neoplastic brain (set as 100%), qPCR did not show any significant difference in the amount of KLF8-mRNA in LGG (97.1%) and GBM (99.3%).</p

PCR and WB of KLF8 after shRNA knockdown in U87-MG.

<p>(A) U87-MG cells transfected with either scrambled (scr) or KLF8-shRNA (kd) were cultivated for up to 3 days (day 0 = day of seeding). Cells were harvested every 24 hrs and RNA was isolated, transcribed into cDNA and amplified by qPCR; data were normalized relative to levels of the house keeping gene TBP. Semi-quantitative qPCR displayed a clear knock-down in KLF8 expression already 48 hrs after transfection (day 0). Expression levels decreased to about 10% in KLF8-shRNA treated cells compared to cells treated with scrambled shRNA on day 2 after seeding. (B) Subsequent Western Blot analysis of the nuclear fraction of KLF8-kd U87-MG cells on day 4 after seeding revealed that KLF8 protein was still detectable in all transfected U87-MG cells but only to a small extent in the KLF8-knockdown cells indicating that shRNA-knockdown was successful in these transfected cells in concordance with the qPCR results (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0030429#pone-0030429-g005" target="_blank">Figure 5A</a>).</p