Nasopharyngeal mucoepidermoid carcinoma: A case report and review of literature

Background

Salivary gland-type tumors originating in the nasopharynx are rare, and only a few articles about mucoepidermoid carcinomas (MEC) in this location have been reported. We describe one case of nasopharyngeal MEC and, based on a review of the literature, discuss different therapeutic approaches that can be taken regarding the result of histological findings, radiological tests and extent of disease.

Case presentation

A 47-year-old woman diagnosed with mucoepidermoid carcinoma of nasopharynx, T1 N3 M0 (stage IV-B) was treated in 2007 with a combination of radiotherapy and chemotherapy to a maximum dose of 70 Gy and concomitant Cisplatin during the radiation. One year later, with the head and neck disease under control, mediastinal nodes relapse appeared which were treated with exclusive radiotherapy to a maximum dose of 65 Gy. One year after the first relapse, a second relapse was detected in the right lung, next to the previously treated mediastinal regions, and the patient initiated a treatment with exclusive chemotherapy based on TPF scheme.

Conclusion

For limited or resectable MEC, combined surgery with radiotherapy, or radiochemotherapy, should be considered the main treatment policy. On the other hand, in poorly differentiated, unresectable tumors or nasopharyngeal MEC, radiochemotherapy could be currently the main treatment approach.     

Curcumin pre-treatment may protect against mitochondrial damage in LRRK2-mutant Parkinson's disease and healthy control fibroblasts

Mitochondrial dysfunction has been proposed as one of the pathobiological underpinnings in Parkinson's disease. Environmental stressors, such as paraquat, induce mitochondrial dysfunction and promote reactive oxygen species production. Targeting oxidative stress pathways could prevent mitochondrial dysfunction and thereby halt the neurodegeneration in Parkinson's disease. Since curcumin is touted as an antioxidant and neuroprotective agent, the aim of this study was to investigate if curcumin is a suitable therapy to target mitochondrial dysfunction in Parkinson's disease using a paraquat-toxicity induced model in fibroblasts from LRRK2-mutation positive Parkinson's disease individuals and healthy controls. The fibroblasts were exposed to five treatment groups, (i) untreated, (ii) curcumin only, (iii) paraquat only, (iv) pre-curcumin group: with curcumin for 2hr followed by paraquat for 24hr and (v) post-curcumin group: with paraquat for 24hr followed by curcumin for 2hr. Mitochondrial function was determined by measuring three parameters of mitochondrial respiration (maximal respiration, ATP-associated respiration, and spare respiratory capacity) using the Seahorse XF^e96 Extracellular Flux Analyzer. As expected, paraquat effectively disrupted mitochondrial function for all parameters. Pre-curcumin treatment improved maximal and ATP-associated respiration whereas, post-curcumin treatment had no effect. These findings indicate that curcumin may be most beneficial as a pre-treatment before toxin exposure, which has implications for its therapeutic use. These promising findings warrant future studies testing different curcumin dosages, exposure times and curcumin formulations in larger sample sizes of Parkinson's disease and control participants.     

Regenerative potential of human muscle stem cells in chronic inflammation

Introduction

Chronic inflammation is a profound systemic modification of the cellular microenvironment which could affect survival, repair and maintenance of muscle stem cells. The aim of this study was to define the role of chronic inflammation on the regenerative potential of satellite cells in human muscle.

Methods

As a model for chronic inflammation, 11 patients suffering from rheumatoid arthritis (RA) were included together with 16 patients with osteoarthritis (OA) as controls. The mean age of both groups was 64 years, with more females in the RA group compared to the OA group. During elective knee replacement surgery, a muscle biopsy was taken from the distal musculus vastus medialis. Cell populations from four RA and eight OA patients were used for extensive phenotyping because these cell populations showed no spontaneous differentiation and myogenic purity greater than 75% after explantation.

Results

After mononuclear cell explantation, myogenic purity, viability, proliferation index, number of colonies, myogenic colonies, growth speed, maximum number of population doublings and fusion index were not different between RA and OA patients. Furthermore, the expression of proteins involved in replicative and stress-induced premature senescence and apoptosis, including p16, p21, p53, hTERT and cleaved caspase-3, was not different between RA and OA patients. Mean telomere length was shorter in the RA group compared to the OA group.

Conclusions

In the present study we found evidence that chronic inflammation in RA does not affect the in vitro regenerative potential of human satellite cells. Identification of mechanisms influencing muscle regeneration by modulation of its microenvironment may, therefore, be more appropriate.     

Reference genes for quantitative reverse transcription-polymerase chain reaction expression studies in wild and cultivated peanut

Background

Molecular genetic studies on rare tumour entities, such as bone tumours, often require the use of decalcified, formalin-fixed, paraffin-embedded tissue (dFFPE) samples. Regardless of which decalcification procedure is used, this introduces a vast breakdown of DNA that precludes the possibility of further molecular genetic testing. We set out to establish a robust protocol that would overcome these intrinsic hurdles for bone tumour research.

Findings

The goal of our study was to establish a protocol, using a modified DNA isolation procedure and quality controls, to select decalcified samples suitable for array-CGH testing. Archival paraffin blocks were obtained from 9 different pathology departments throughout Europe, using different fixation, embedding and decalcification procedures, in order to preclude a bias for certain lab protocols. Isolated DNA samples were subjected to direct chemical labelling and enzymatic labelling systems and were hybridised on a high resolution oligonucleotide chip containing 44,000 reporter elements. Genomic alterations (gains and losses) were readily detected in most of the samples analysed. For example, both homozygous deletions of 0.6 Mb and high level of amplifications of 0.7 Mb were identified.

Conclusions

We established a robust protocol for molecular genetic testing of dFFPE derived DNA, irrespective of fixation, decalcification or sample type used. This approach may greatly facilitate further genetic testing on rare tumour entities where archival decalcified, formalin fixed samples are the only source.     

Suppression of inflammatory immune responses in celiac disease by experimental hookworm infection

We present immunological data from two clinical trials where the effect of experimental human hookworm (Necator americanus) infection on the pathology of celiac disease was evaluated. We found that basal production of Interferon- (IFN-)γ and Interleukin- (IL-)17A from duodenal biopsy culture was suppressed in hookworm-infected participants compared to uninfected controls. Increased levels of CD4+CD25+Foxp3+ cells in the circulation and mucosa are associated with active celiac disease. We show that this accumulation also occurs during a short-term (1 week) oral gluten challenge, and that hookworm infection suppressed the increase of circulating CD4+CD25+Foxp3+ cells during this challenge period. When duodenal biopsies from hookworm-infected participants were restimulated with the immunodominant gliadin peptide QE65, robust production of IL-2, IFN-γ and IL-17A was detected, even prior to gluten challenge while participants were strictly adhering to a gluten-free diet. Intriguingly, IL-5 was produced only after hookworm infection in response to QE65. Thus we hypothesise that hookworm-induced TH2 and IL-10 cross-regulation of the TH1/TH17 inflammatory response may be responsible for the suppression of these responses during experimental hookworm infection.     

Autophagy as a Neuroprotective Mechanism Against 3-Nitropropionic Acid-Induced Murine Astrocyte Cell Death

Huntington’s disease (HD) is a genetic neurodegenerative disorder that is characterized by severe striatal atrophy with extensive neuronal loss and gliosis. Although the molecular mechanism is not well understood, experimental studies use the irreversible mitochondrial inhibitor 3-nitropropionic acid (3-NP) to mimic the neuropathological features of HD. In this study, the role of autophagy as a neuroprotective mechanism against 3-NP-induced astrocyte cytotoxicity was evaluated. Autophagy is a catabolic process that is essential for the turnover of cytosolic proteins and organelles and is involved in the modulation of cell death and survival. We showed that 3-NP-induced apoptosis, which was accompanied by Bax and Beclin-1 upregulation, was dependent on acidic vesicular organelle (AVO) formation after a continuous exposure to 3-NP for 12 h. The upregulation of Bax and Beclin-1 as well as AVO formation were normalized 24 h after 3-NP exposure.     

Biosynthetic chlorination of the piperazate residue in kutzneride biosynthesis by KthP

Kutznerides 2 and 8 of the cyclic hexadepsipeptide family of antifungal natural products from the soil actinomycete Kutzneria sp. 744 contain two sets of chlorinated residues, a 6,7-dichlorohexahydropyrroloindole moiety derived from dichlorotryptophan and a 5-chloropiperazate moiety, as well as a methylcyclopropylglycine residue that may arise from isoleucine via a cryptic chlorination pathway. Previous studies identified KtzD, KtzQ, and KtzR as three halogenases in the kutzneride pathway but left no candidate for installing the C5 chlorine on piperazate. On the basis of analysis of the complete genome sequence of Kutzneria, we now identify a fourth halogenase in the pathway whose gene is separated from the defined kutzneride cluster by 12 open reading frames. KthP (kutzneride halogenase for piperazate) is a mononuclear nonheme iron halogenase that acts on the piperazyl ring tethered by a thioester linkage to the holo forms of thiolation domains. MS analysis of the protein-bound product confirmed chlorination of the piperazate framework from the (3S)- but not the (3R)-piperazyl-S-pantetheinyl thiolation proteins. After thioesterase-mediated release, nuclear magnetic resonance was used to assign the free imino acid as (3S,5S)-5-chloropiperazate, distinct from the 3S,5R stereoisomer reported in the mature kutznerides. These results demonstrate that a fourth halogenase, KthP, is active in the kutzneride biosynthetic pathway and suggest further processing of the (3S,5S)-5-chloropiperazate during subsequent incorporation into the kutzneride depsipeptide frameworks.     

Vital role for Plasmodium berghei Kinesin8B in axoneme assembly during male gamete formation and mosquito transmission

Sexual development is an essential phase in the Plasmodium life cycle, where male gametogenesis is an unusual and extraordinarily rapid process. It produces 8 haploid motile microgametes, from a microgametocyte within 15 minutes. Its unique achievement lies in linking the assembly of 8 axonemes in the cytoplasm to the three rounds of intranuclear genome replication, forming motile microgametes, which are expelled in a process called exflagellation. Surprisingly little is known about the actors involved in these processes. We are interested in kinesins, molecular motors that could play potential roles in male gametogenesis. We have undertaken a functional characterization in Plasmodium berghei of kinesin‐8B (PbKIN8B) expressed specifically in male gametocytes and gametes. By generating Pbkin8B‐gfp parasites, we show that PbKIN8B is specifically expressed during male gametogenesis and is associated with the axoneme. We created a ΔPbkin8B knockout cell line and analysed the consequences of the absence of PbKIN8B on male gametogenesis. We show that the ability to produce sexually differentiated gametocytes is not affected in ΔPbkin8B parasites and that the 3 rounds of genome replication occur normally. Nevertheless, the development to free motile microgametes is halted and the life cycle is interrupted in vivo. Ultrastructural analysis revealed that intranuclear mitoses are unaffected whereas cytoplasmic microtubules, although assembled in doublets and elongated, fail to assemble in the normal axonemal ‘9+2' structure and become motile. Absence of a functional axoneme prevented microgamete assembly and release from the microgametocyte, severely reducing infection of the mosquito vector. This is the first functional study of a kinesin involved in male gametogenesis. These results reveal a previously unknown role for PbKIN8B in male gametogenesis, providing new insights into Plasmodium flagellar formation.     

Repression of Osteoblast Maturation by ERRα Accounts for Bone Loss Induced by Estrogen Deficiency

ERRα is an orphan member of the nuclear receptor family, the complete inactivation of which confers resistance to bone loss induced by ageing and estrogen withdrawal to female mice in correlation with increased bone formation in vivo. Furthermore ERRα negatively regulates the commitment of mesenchymal cells to the osteoblast lineage ex vivo as well as later steps of osteoblast maturation. We searched to determine whether the activities of ERRα on osteoblast maturation are responsible for one or both types of in vivo induced bone loss. To this end we have generated conditional knock out mice in which the receptor is normally present during early osteoblast differentiation but inactivated upon osteoblast maturation. Bone ageing in these animals was similar to that observed for control animals. In contrast conditional ERRαKO mice were completely resistant to bone loss induced by ovariectomy. We conclude that the late (maturation), but not early (commitment), negative effects of ERRα on the osteoblast lineage contribute to the reduced bone mineral density observed upon estrogen deficiency.