Correction: Identification of lysine methylation in the core GTPase domain by GoMADScan.

[This corrects the article DOI: 10.1371/journal.pone.0219436.].

Identification of lysine methylation in the core GTPase domain by GoMADScan.

RAS is the founding member of a superfamily of GTPases and regulates signaling pathways involved in cellular growth control. While recent studies have shown that the activation state of RAS can be controlled by lysine ubiquitylation and acetylation, the existence of lysine methylation of the RAS superfamily GTPases remains unexplored. In contrast to acetylation, methylation does not alter the side chain charge and it has been challenging to deduce its impact on protein structure by conventional amino acid substitutions. Herein, we investigate lysine methylation on RAS and RAS-related GTPases. We developed GoMADScan (Go language-based Modification Associated Database Scanner), a new user-friendly application that scans and extracts posttranslationally modified peptides from databases. The GoMADScan search on PhosphoSitePlus databases identified methylation of conserved lysine residues in the core GTPase domain of RAS superfamily GTPases, including residues corresponding to RAS Lys-5, Lys-16, and Lys-117. To follow up on these observations, we immunoprecipitated endogenous RAS from HEK293T cells, conducted mass spectrometric analysis and found that RAS residues, Lys-5 and Lys-147, undergo dimethylation and monomethylation, respectively. Since mutations of Lys-5 have been found in cancers and RASopathies, we set up molecular dynamics (MD) simulations to assess the putative impact of Lys-5 dimethylation on RAS structure. Results from our MD analyses predict that dimethylation of Lys-5 does not significantly alter RAS conformation, suggesting that Lys-5 methylation may alter existing protein interactions or create a docking site to foster new interactions. Taken together, our findings uncover the existence of lysine methylation as a novel posttranslational modification associated with RAS and the RAS superfamily GTPases, and putative impact of Lys-5 dimethylation on RAS structure.

Acute encephalopathy secondary to dabrafenib and trametinib in BRAF-positive metastatic adenocarcinoma of the lung.

Acute encephalopathy secondary to targeted therapy with BRAF inhibitors is uncommon. There are few case reports in patients with metastatic melanoma who received treatment with dabrafenib and trametinib, and developed acute confusion. The encephalopathy appears to resolve after the discontinuation of offending drug, with patient returning to their baseline mentation and functional ability. The mechanism of the encephalopathy has been unclear. Unlike posterior reversible encephalopathy syndrome, which has been reported with vemurafenib and cobimetinib combination in melanoma patients, there are generally no acute imaging abnormalities observed (e.g. on computed tomography and magnetic resonance imaging brain scans). We report a case of acute encephalopathy in a patient with BRAF mutated metastatic lung cancer due to dabrafenib and trametinib treatment. With the increasing use of targeted therapies in lung cancer treatments, it is important for clinicians to be aware of potentially toxic effects of novel treatments.

Profile of pembrolizumab in the treatment of head and neck squamous cell carcinoma: design development and place in therapy.

Head and neck squamous cell cancer (HNSCC) is the sixth most common malignancy worldwide, and despite advances in cytotoxic, surgical and radiation techniques, outcomes are still poor in those with both locally advanced and metastatic diseases. The need for development of better therapeutics along with a greater understanding of the relationship between the immune system and malignancies has led to a new therapeutic modality, immune modulators, particularly checkpoint inhibitors in HNSCC. It is now well recognized that HNSCC circumvents crucial pathways utilized by the immune system to escape surveillance. These hijacked pathways include impairing tumor antigen presentation machinery and co-opting checkpoint receptors. This understanding has led to the development of monoclonal antibodies targeting checkpoint receptors and has resulted in promising outcomes in HNSCC. This article describes the mechanisms that HNSCC utilizes to escape immune surveillance, clinical impact of checkpoint inhibitors (with a focus on pembrolizumab), ongoing studies, and future directions.

Primary Cardiac Sarcoma: 25-Year Cleveland Clinic Experience.

BACKGROUND: Cardiac sarcomas are rare and have a poor prognosis. The median overall survival remains dismal and has been reported ranging from 6 months to a few years. Primary cardiac sarcoma is the most common malignant tumor comprising approximately 95% of all malignant tumors of the heart. METHODS: We conducted a retrospective chart review in a single institution of patients diagnosed between March 1988 and April 2013. A total of 42 patients were identified. The following variables were studied: age at diagnosis, year of diagnosis, sex, stage, site of tumor involvement, tumor histology, grade, treatment modality, type of chemotherapy, and survival outcome. The overall median follow-up time was 49.5 months. RESULTS: The most common histologic type was angiosarcoma. Overall estimated median survival (EMS) was 25 months. Tumors involving the left side of the heart and pericardium demonstrated better survival. Patients who received multimodality treatment (any combination of surgery, radiation therapy, and chemotherapy) had an EMS of 36.5 months compared with 14.1 months for patients treated with surgery, radiation therapy, or chemotherapy only (P=0.05). CONCLUSIONS: Cardiac sarcoma is a lethal tumor with an EMS of 25 months. The tumor histology could be a possible predictor of better survival. Although selection bias may have been present, multimodality therapy (surgery, radiation therapy, and chemotherapy) was associated with improved survival.

Teriparatide induced delayed persistent hypercalcemia.

Teriparatide, a recombinant PTH, is an anabolic treatment for osteoporosis that increases bone density. Transient hypercalcemia is a reported side effect of teriparatide that is seen few hours following administration of teriparatide and resolves usually within 16 hours of drug administration. Persistent hypercalcemia, although not observed in clinical trials, is rarely reported. The current case describes a rare complication of teriparatide induced delayed persistent hypercalcemia.

Practical recommendations on incorporating new oral anticoagulants into routine practice.

The use of new oral anticoagulants (NOACs) is expected to rise significantly in upcoming years. Therefore, it is important to understand the potential uses, side effects, and management of these agents in routine practice. NOACs have major pharmacologic advantages over warfarin, including a rapid onset and offset of action, fewer drug interactions, and predictable pharmacokinetics. These agents are gaining popularity among both physicians and patients because of their ease of administration and the advantage of eliminating the requirement for regular coagulation monitoring. NOACs work to prevent and treat thrombosis by targeting either thrombin (as with dabigatran) or factor Xa (as with rivaroxaban and apixaban). In this review, we discuss practical recommendations for the use of NOACs and the risks and benefits of incorporating them into routine practice.

What should I know before ordering a bone marrow aspiration/biopsy in patients with vitamin B12 deficiency?

Vitamin B12 deficiency is a well recognised cause of macrocytic anaemia and bone marrow failure. Bone marrow aspiration/biopsy is infrequently indicated for the diagnosis in this setting. However, if a bone marrow aspiration/biopsy is performed, it is important to recognise that it may show dysplastic changes mimicking myelodysplastic syndrome (MDS) or acute leukaemia. We report a case of a 66-year-old non-vegetarian man presenting with generalised weakness for 1 month and misdiagnosed on bone marrow biopsy as MDS. However, laboratory investigations revealed severe deficiency of vitamin B12. Four weeks after starting vitamin B12 replacement the patient's complete blood counts reverted to normal.