A Multi-Layered Computational Structural Genomics Approach Enhances Domain-Specific Interpretation of Kleefstra Syndrome Variants in EHMT1.

This study investigates the functional significance of assorted variants of uncertain significance (VUS) in euchromatic histone lysine methyltransferase 1 (EHMT1), which is critical for early development and normal physiology. EHMT1 mutations cause Kleefstra syndrome and are linked to various human cancers. However, accurate functional interpretation of these variants are yet to be made, limiting diagnoses and future research. To overcome this, we integrate conventional tools for variant calling with computational biophysics and biochemistry to conduct multi-layered mechanistic analyses of the SET catalytic domain of EHMT1, which is critical for this protein function. We use molecular mechanics and molecular dynamics (MD)-based metrics to analyze the SET domain structure and functional motions resulting from 97 Kleefstra syndrome missense variants within this domain. Our approach allows us to classify the variants in a mechanistic manner into SV (Structural Variant), DV (Dynamic Variant), SDV (Structural and Dynamic Variant), and VUS (Variant of Uncertain Significance). Our findings reveal that the damaging variants are mostly mapped around the active site, substrate binding site, and pre-SET regions. Overall, we report an improvement for this method over conventional tools for variant interpretation and simultaneously provide a molecular mechanism of variant dysfunction.

A multi-layered computational structural genomics approach enhances domain-specific interpretation of Kleefstra syndrome variants in EHMT1.

This study investigates the functional significance of assorted variants of uncertain significance (VUS) in euchromatic histone lysine methyltransferase 1 (EHMT1), which is critical for early development and normal physiology. EHMT1 mutations cause Kleefstra syndrome and are linked to various human cancers. However, accurate functional interpretations of these variants are yet to be made, limiting diagnoses and future research. To overcome this, we integrate conventional tools for variant calling with computational biophysics and biochemistry to conduct multi-layered mechanistic analyses of the SET catalytic domain of EHMT1, which is critical for this protein function. We use molecular mechanics and molecular dynamics (MD)-based metrics to analyze the SET domain structure and functional motions resulting from 97 Kleefstra syndrome missense variants within the domain. Our approach allows us to classify the variants in a mechanistic manner into SV (Structural Variant), DV (Dynamic Variant), SDV (Structural and Dynamic Variant), and VUS (Variant of Uncertain Significance). Our findings reveal that the damaging variants are mostly mapped around the active site, substrate binding site, and pre-SET regions. Overall, we report an improvement for this method over conventional tools for variant interpretation and simultaneously provide a molecular mechanism for variant dysfunction.

Phosphoethanolamine induces caspase-independent cell death by reducing the expression of C-RAF and inhibits tumor growth in human melanoma model.

Phosphoethanolamine (PEA) is a fundamental precursor during the biosynthesis of cell membranes phospholipids. In the past few years, it has been described as a potential antitumor agent. In previous studies, we demonstrated that PEA showed antitumor properties in vitro and in vivo in a wide range of tumor cell lines. Herein, we showed that PEA possesses cytotoxic properties and notably revealed to induce caspase-independent cell death. Of interest, we provided evidence that PEA inhibits melanoma cells proliferation through the reduction of C-RAF. Molecular docking of PEA evidenced that this compound indeed fits satisfactory in the binding site located between the dimers of C-RAF protein with 107,01 Šand score of -29,62. Also, PEA arrested A2058 cells at G2/M phase in the cell cycle. Moreover, cell proliferation, migration and adhesion capacities of A2058 cells were also inhibited by PEA. Most importantly, PEA inhibited tumor growth of melanoma tumors and prolonged survival rate of mice. Also, PEA induced a significant immune response in a syngeneic metastatic melanoma model. Taken together, these data indicate that PEA is a promising candidate for future developments in cancer field.

Edelfosine: An Antitumor Drug Prototype.

BACKGROUND: Lung cancer is the most prevalent cancer and a high fatality disease. Despite of all available therapeutic approaches, drug resistance of chemotherapy agents for patients remain as an obstacle. New drugs integrating immunotherapeutic and conventional cytotoxic effects is a powerful strategy for the treatment of cancer to overcome this limitation. Antineoplastic phospholipids combine both of these activities by affecting lipid metabolism and signaling through lipid rafts. Therefore, they emerge as interesting scaffolds for designing new drugs. OBJECTIVE: We aimed to evaluate antineoplastic phospholipids as scaffolds for designing new drugs for lung cancer treatment. METHODS: The initial screening in A549 cells was performed by MTT assay. Others cytotoxic effects were evaluated in A549 cells by clonogenic assay, Matrigel 3D culture and flow cytometry analyses of cell cycle, apoptosis, mitochondrial membrane electronic potential and superoxide production. Immunological effects of ED were accessed on dendritic cells (DCs) and the expression of some markers were evaluated by flow cytometry. In vivo lung colonization analysis was performed after intravenously injection of A549 cells and daily treatment with ED. RESULTS: Herein, ED showed to be the most efficient compound concerning cytotoxic, thereby, ED was selected for following tests. ED showed a cytotoxic profile in both monolayer and 3D culture and also in vivo models using A549 cells. This profile is due to G0/G1 phase cellular arrest and apoptosis drove by mitochondrial membrane depolarization and superoxide overproduction. Moreover, ED modulated DCs toward an activated pattern by the increased expression of CD83 and a remarkable decreased expression of PD-L1/CD274 on DCs membrane. CONCLUSIONS: Thus, ED is an interesting antitumor drug prototype due to not only its direct cellular cytotoxicity but also given its immunological features.