Florian Gessler

Dr. Florian Gessler

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Research Focus & Metrics

Academic Career Length

16Years (2011-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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27 March 2018 in Neurosurgery
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FGFlorian Gessler
Florian Gessler
JBJoshua Bernstock
Joshua Bernstock
ABAnne Braczynski
Anne Braczynski
SLStephanie Lescher
Stephanie Lescher
PBPeter Baumgarten
Peter Baumgarten
CSChristian Senft
Christian Senft
BACKGROUND: Previous studies addressing the influence of surgery on the outcome of patients with glioblastomas (GBM) have not addressed molecular markers. The value of surgery versus the tumor's major biological markers remains unclear. OBJECTIVE: We investigate the extent of resection as a prognosticator for patients with newly diagnosed primary GBM with the incorporation of molecular diagnostics as per the updated WHO 2016 diagnostic criteria for GBM. METHODS: Patients with newly diagnosed GBM who underwent resection were prospectively included within a database. We analyzed patients with newly diagnosed GBM and excluded patients who presented with IDH1 R132H mutations. Gross total resection (GTR) was defined as complete removal of enhancing disease. RESULTS: One hundred seventy-five patients were included within the analysis. One hundred four patients (59.4%) had GTR, 71 patients (40.6%) had subtotal or partial resection. Eighty patients (45.7%) displayed O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation, 95 patients (54.3%) showed no MGMT promoter methylation. In Cox regression analysis, MGMT promoter methylation (hazard ratio [HR] 1.55; 95% confidence interval [CI], 1.01-2.19; P = .0133) and GTR (HR 1.48; 95% CI, 1.06-2.07; P = .0206) were significantly associated with favorable progression-free survival. MGMT promoter methylation (HR 2.13; 95% CI, 1.45-3.12; P = .0001) and GTR (HR 1.81; 95% CI, 1.24-2.63; P = .002) were associated with favorable overall survival (OS). Of other risk factors analyzed, age (>60 vs ≤ 60 yr) was significantly associated with progression-free survival (HR 1.60; 95% CI, 1.14-2.24; P = .006) and OS (HR 2.19; 95% CI, 1.51-3.19; P < .0001). CONCLUSION: GTR and MGMT promoter methylation are independent prognosticators for improved overall and progression-free survival in a homogeneous cohort of newly diagnosed patients with IDH wild-type glioblastoma.

7 April 2015 in BMC Cancer
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JMJens Mani
Jens Mani
SVStefan Vallo
Stefan Vallo
SRStefanie Rakel
Stefanie Rakel
PAPatrick Antonietti
Patrick Antonietti
FGFlorian Gessler
Florian Gessler
Donat KögelDonat Kögel
Donat Kögel
Acquired resistance to standard chemotherapy causes treatment failure in patients with metastatic bladder cancer. Overexpression of pro-survival Bcl-2 family proteins has been associated with a poor chemotherapeutic response, suggesting that Bcl-2-targeted therapy may be a feasible strategy in patients with these tumors. The small-molecule pan-Bcl-2 inhibitor (−)-gossypol (AT-101) is known to induce apoptotic cell death, but can also induce autophagy through release of the pro-autophagic BH3 only protein Beclin-1 from Bcl-2. The potential therapeutic effects of (−)-gossypol in chemoresistant bladder cancer and the role of autophagy in this context are hitherto unknown. Cisplatin (5637rCDDP1000, RT4rCDDP1000) and gemcitabine (5637rGEMCI20, RT4rGEMCI20) chemoresistant sub-lines of the chemo-sensitive bladder cancer cell lines 5637 and RT4 were established for the investigation of acquired resistance mechanisms. Cell lines carrying a stable lentiviral knockdown of the core autophagy regulator ATG5 were created from chemosensitive 5637 and chemoresistant 5637rGEMCI20 and 5637rCDDP1000 cell lines. Cell death and autophagy were quantified by FACS analysis of propidium iodide, Annexin and Lysotracker staining, as well as LC3 translocation. Here we demonstrate that (−)-gossypol induces an apoptotic type of cell death in 5637 and RT4 cells which is partially inhibited by the pan-caspase inhibitor z-VAD. Cisplatin- and gemcitabine-resistant bladder cancer cells exhibit enhanced basal and drug-induced autophagosome formation and lysosomal activity which is accompanied by an attenuated apoptotic cell death after treatment with both (−)-gossypol and ABT-737, a Bcl-2 inhibitor which spares Mcl-1, in comparison to parental cells. Knockdown of ATG5 and inhibition of autophagy by 3-MA had no discernible effect on apoptotic cell death induced by (−)-gossypol and ABT-737 in parental 5637 cells, but evoked a significant increase in early apoptosis and overall cell death in BH3 mimetic-treated 5637rGEMCI20 and 5637rCDDP1000 cells. Our findings show for the first time that (−)-gossypol concomitantly triggers apoptosis and a cytoprotective type of autophagy in bladder cancer and support the notion that enhanced autophagy may underlie the chemoresistant phenotype of these tumors. Simultaneous targeting of Bcl-2 proteins and the autophagy pathway may be an efficient new strategy to overcome their “autophagy addiction” and acquired resistance to current therapy.

1 July 2015 in Neurosurgery
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FGFlorian Gessler
Florian Gessler
MFMarie-Thérèse Forster
Marie-Thérèse Forster
SDStephan Duetzmann
Stephan Duetzmann
MMMichel Mittelbronn
Michel Mittelbronn
EHElke Hattingen
Elke Hattingen
CSChristian Senft
Christian Senft
BACKGROUND:. Evidence suggests that extent of resection (EOR) is a prognostic factor for patients harboring gliomas. Recent studies have displayed the i

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CCChristopher Chang
Christopher Chang
VCVelina S. Chavarro
Velina S. Chavarro
JGJakob Gerstl
Jakob Gerstl
SBSarah E Blitz
Sarah E Blitz
LSLennard Spanehl
Lennard Spanehl
JBJoshua Bernstock
Joshua Bernstock
Glioblastoma is the most common and lethal central nervous system malignancy with a median survival after progression of only 6–9 months. Major biochemical mechanisms implicated in glioblastoma recurrence include aberrant molecular pathways, a recurrence-inducing tumor microenvironment, and epigenetic modifications. Contemporary standard-of-care (surgery, radiation, chemotherapy, and tumor treating fields) helps to control the primary tumor but rarely prevents relapse. Cytoreductive treatment such as surgery has shown benefits in recurrent glioblastoma; however, its use remains controversial. Several innovative treatments are emerging for recurrent glioblastoma, including checkpoint inhibitors, chimeric antigen receptor T cell therapy, oncolytic virotherapy, nanoparticle delivery, laser interstitial thermal therapy, and photodynamic therapy. This review seeks to provide readers with an overview of (1) recent discoveries in the molecular basis of recurrence; (2) the role of surgery in treating recurrence; and (3) novel treatment paradigms emerging for recurrent glioblastoma.

7 August 2017 in Scientific Reports
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JBJoshua Bernstock
Joshua Bernstock
DYDaniel Ye
Daniel Ye
FGFlorian Gessler
Florian Gessler
YLYang-Ja Lee
Yang-Ja Lee
LPLuca Peruzzotti-Jametti
Luca Peruzzotti-Jametti
JHJohn M. Hallenbeck
John M. Hallenbeck
Protein SUMOylation is a dynamic post-translational modification shown to be involved in a diverse set of physiologic processes throughout the cell. SUMOylation has also been shown to play a role in the pathobiology of myriad cancers, one of which is glioblastoma multiforme (GBM). As such, the clinical significance and therapeutic utility offered via the selective control of global SUMOylation is readily apparent. There are, however, relatively few known/effective inhibitors of global SUMO-conjugation. Herein we describe the identification of topotecan as a novel inhibitor of global SUMOylation. We also provide evidence that inhibition of SUMOylation by topotecan is associated with reduced levels of CDK6 and HIF-1α, as well as pronounced changes in cell cycle progression and cellular metabolism, thereby highlighting its putative role as an adjuvant therapy in defined GBM patient populations.

1 June 2011 in Neuroscience Letters
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FGFlorian Gessler
Florian Gessler
VVValerie Voss
Valerie Voss
VSVolker Seifert
Volker Seifert
RGRüdiger Gerlach
Rüdiger Gerlach
Donat KögelDonat Kögel
Donat Kögel