Survival Benefit of Hyperthermic Intraperitoneal Chemotherapy for Recurrent Ovarian Cancer: A Multi-institutional Case Control Study

Background

Hyperthermic intraperitoneal chemotherapy (HIPEC) and complete surgical removal of the tumor, in relapsing patients may provide a clinical benefit. There is no consensus considering the place of HIPEC for patients who had first ovarian cancer relapse. To assess for possible efficacy of HIPEC on overall survival (OS) rates in this situation, we performed a multi-institutional study.

Methods

The current study was a retrospective case control multi-institutional study comparing a group of patients treated with HIPEC to a group of patients treated without HIPEC. Inclusion criteria were first relapse of a serous ovarian carcinoma and >6 months after the end of initial treatment. Exclusion criteria were another pathological subtype of ovarian cancer, a relapse at <6 months after initial treatment, and a second relapse or more. We aimed to assess OS, morbidity, and mortality rates and prognostic factors.

Results

From June 1997–July 2011, 42 patients were included, 23 in the HIPEC group and 19 in the control group. Each patient from the two groups had a complete secondary surgery at the time of the first relapse. At 4 years OS was 75.6 % in the HIPEC group and 19.4 % in the control group (p = 0.013). In a multivariate analysis, HIPEC and interval-free before the end of initial treatment were both independent prognostic factors.

Conclusion

When compared to the control group, complete secondary surgery and HIPEC appear to afford a better OS rate than complete secondary surgery alone, in case of first ovarian cancer relapse. Further randomized trials are warranted to confirm these results.     

Chlorotoxin: A Helpful Natural Scorpion Peptide to Diagnose Glioma and Fight Tumor Invasion

Chlorotoxin is a small 36 amino-acid peptide identified from the venom of the scorpion Leiurus quinquestriatus. Initially, chlorotoxin was used as a pharmacological tool to characterize chloride channels. While studying glioma-specific chloride currents, it was soon discovered that chlorotoxin possesses targeting properties towards cancer cells including glioma, melanoma, small cell lung carcinoma, neuroblastoma and medulloblastoma. The investigation of the mechanism of action of chlorotoxin has been challenging because its cell surface receptor target remains under questioning since two other receptors have been claimed besides chloride channels. Efforts on chlorotoxin-based applications focused on producing analogues helpful for glioma diagnosis, imaging and treatment. These efforts are welcome since gliomas are very aggressive brain cancers, close to impossible to cure with the current therapeutic arsenal. Among all the chlorotoxin-based strategies, the most promising one to enhance patient mean survival time appears to be the use of chlorotoxin as a targeting agent for the delivery of anti-tumor agents. Finally, the discovery of chlorotoxin has led to the screening of other scorpion venoms to identify chlorotoxin-like peptides. So far several new candidates have been identified. Only detailed research and clinical investigations will tell us if they share the same anti-tumor potential as chlorotoxin.     

Direct inhibition by nitric oxide of the transcriptional ferric uptake regulation protein via nitrosylation of the iron

Ferric uptake regulation protein (Fur) is a bacterial global regulator that uses iron as a cofactor to bind to specific DNA sequences. The function of Fur is not limited to iron homeostasis. A wide variety of genes involved in various mechanisms such as oxidative and acid stresses are under Fur control. Flavohemoglobin (Hmp) is an NO-detoxifying enzyme induced by NO and nitrosothiol compounds. Fur recently was found to regulate hmp in Salmonella typhimurium, and in Escherichia coli, the iron-chelating agent 2,2'-dipyridyl induces hmp expression. We now establish direct inhibition of E. coli Fur activity by NO. By using chromosomal Fur-regulated lacZ reporter fusion in E. coli, Fur activity is switched off by NO at micromolar concentration. In vitro Fur DNA-binding activity, as measured by protection of restriction site in aerobactin promoter, is directly sensitive to NO. NO reacts with Fe(II) in purified FeFur protein to form a S = 12 low-spin FeFur-NO complex with a g = 2.03 EPR signal. Appearance of the same EPR signal in NO-treated cells links nitrosylation of the iron with Fur inhibition. The nitrosylated Fur protein is still a dimer and is stable in anaerobiosis but slowly decays in air. This inhibition probably arises from a conformational switch, leading to an inactive dimeric protein. These data establish a link between control of iron metabolism and the response to NO effects.     

The nuclear bile acid receptor FXR is a PKA- and FOXA2-sensitive activator of fasting hepatic gluconeogenesis

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A neurosurgical phantom-based training system with ultrasound simulation

Background

Brain tumor surgeries are associated with a high technical and personal effort. The required interactions between the surgeon and the technical components, such as neuronavigation, surgical instruments and intraoperative imaging, are complex and demand innovative training solutions and standardized evaluation methods. Phantom-based training systems could be useful in complementing the existing surgical education and training.

Methods

A prototype of a phantom-based training system was developed, intended for standardized training of important aspects of brain tumor surgery based on real patient data. The head phantom consists of a three-part construction that includes a reusable base and adapter, as well as a changeable module for single use. Training covers surgical planning of the optimal access path, the setup of the navigation system including the registration of the head phantom, as well as the navigated craniotomy with real instruments. Tracked instruments during the simulation and predefined access paths constitute the basis for the essential objective training feedback.

Results

The prototype was evaluated in a pilot study by assistant physicians at different education levels. They performed a complete simulation and a final assessment using an evaluation questionnaire. The analysis of the questionnaire showed the evaluation result as “good” for the phantom construction and the used materials. The learning effect concerning the navigated planning was evaluated as “very good”, as well as having the effect of increasing safety for the surgeon before planning and conducting craniotomies independently on patients.

Conclusions

The training system represents a promising approach for the future training of neurosurgeons. It aims to improve surgical skill training by creating a more realistic simulation in a non-risk environment. Hence, it could help to bridge the gap between theoretical and practical training with the potential to benefit both physicians and patients.     

Activation of the pseudokinase MLKL unleashes the four-helix bundle domain to induce membrane localization and necroptotic cell death

Necroptosis is considered to be complementary to the classical caspase-dependent programmed cell death pathway, apoptosis. The pseudokinase Mixed Lineage Kinase Domain-Like (MLKL) is an essential effector protein in the necroptotic cell death pathway downstream of the protein kinase Receptor Interacting Protein Kinase-3 (RIPK3). How MLKL causes cell death is unclear, however RIPK3–mediated phosphorylation of the activation loop in MLKL trips a molecular switch to induce necroptotic cell death. Here, we show that the MLKL pseudokinase domain acts as a latch to restrain the N-terminal four-helix bundle (4HB) domain and that unleashing this domain results in formation of a high-molecular-weight, membrane-localized complex and cell death. Using alanine-scanning mutagenesis, we identified two clusters of residues on opposing faces of the 4HB domain that were required for the 4HB domain to kill cells. The integrity of one cluster was essential for membrane localization, whereas MLKL mutations in the other cluster did not prevent membrane translocation but prevented killing; this demonstrates that membrane localization is necessary, but insufficient, to induce cell death. Finally, we identified a small molecule that binds the nucleotide binding site within the MLKL pseudokinase domain and retards MLKL translocation to membranes, thereby preventing necroptosis. This inhibitor provides a novel tool to investigate necroptosis and demonstrates the feasibility of using small molecules to target the nucleotide binding site of pseudokinases to modulate signal transduction.Programmed necrosis or “necroptosis” has emerged in the past 5 years as a cell death mechanism that complements the conventional cell death pathway, apoptosis, in multicellular organisms. In contrast to apoptosis, necroptosis does not appear to serve an important role in multicellular organism development (1–3) but participates in the defense against pathogens and is a likely culprit in destructive inflammatory conditions (4–7). Receptor Interacting Protein Kinase-3 (RIPK3) was identified as a key effector of necroptosis in 2009 (4, 5) and its substrate, the pseudokinase Mixed Lineage Kinase Domain-Like (MLKL), in 2012 (8, 9), but the molecular events following RIPK3-mediated phosphorylation of MLKL required to induce cell death are unclear. The RIPK1/RIPK3/MLKL necrosome has been proposed to activate PGAM5 (phosphoglycerate mutase 5) and Drp1 (Dynamin-related protein 1) to cause mitochondrial fragmentation and cell death (10), but the requirement for PGAM5, Drp1, and mitochondria for necroptosis has been questioned (1, 11–13).We described the structure of mouse MLKL revealing that MLKL contains a C-terminal pseudokinase domain and an N-terminal four-helix bundle (4HB) domain connected by a two-helix linker (the “brace” helices) (1). Based on our mutational and biochemical analyses, we proposed that the catalytically inactive pseudokinase domain functions as a molecular switch and that RIPK3-mediated phosphorylation triggers this switch by inducing a conformational change in MLKL (1, 14).Recently it has been proposed that the 4HB domain is the death effector domain within MLKL and that the killing function of MLKL relies on its oligomerization and plasma membrane association (15–18). The stoichiometry of the oligomer is, however, contentious and has been reported to contain three (15), four (16), and possibly six (17) MLKL protomers. Furthermore, several mechanisms for how this oligomer causes cell death have been proposed: Cai et al. proposed it activates the calcium channel protein Tprm7 and promotes calcium influx (15), Chen et al. showed it increased sodium influx (16), and Wang et al. proposed that the oligomerized form of MLKL has the ability to bind negatively charged lipids, including phosphoinositides and cardiolipin, which facilitates its disruption of membrane integrity (17), a model supported by a subsequent paper (18).Here, we show that the MLKL 4HB domain is sufficient to induce necroptosis and identify several charged residues clustered on two faces that are required for this function. Surprisingly the polarity of several of these charged residues is not conserved between mouse and human MLKL, and alanine substitution of negatively charged residues on the α4 helix of the 4HB domain disrupted function. This finding challenges the importance of phospholipid binding to the killing activity of the 4HB domain and illustrates that membrane association cannot solely be attributed to the interaction of poorly conserved basic residues within the MLKL 4HB domain. Intriguingly, mutation of a second cluster of residues on the 4HB domain did not preclude membrane localization or oligomerization but did prevent cell death, illustrating that additional function(s) beyond membrane translocation are required for the 4HB domain to induce cell death. MLKL oligomerization and membrane translocation were also inhibited by a small molecule, compound 1, which we identified on the basis of its affinity for the nucleotide binding site of the MLKL pseudokinase domain. These data support a model for MLKL function whereby the pseudokinase domain of MLKL holds the 4HB domain in check until phosphorylated by RIPK3, which causes a conformational change in the pseudokinase domain to unleash the 4HB domain to oligomerize and associate with membranes. Activation of MLKL can be thwarted by a small MLKL binding molecule, indicating the feasibility of targeting the nucleotide binding or “pseudoactive” sites of pseudokinases, a hitherto unexplored class of therapeutic targets.     

Hypercalcemia is associated with a poor prognosis in lymphoma a retrospective monocentric matched-control study and extensive review of published reported cases

Annals of Hematology - The prognostic significance of hypercalcemia in lymphoma has only been studied on small series to date. We conducted a retrospective, monocentric, matched-control study that...