A patient with PLACK syndrome with a novel splicing mutation in CAST: the evidence for a loss-of-function mechanism through mis-splicing.

PLACK syndrome is a relatively recently defined generalized peeling skin syndrome that has been reported with major skin manifestations and sometimes atypical features. We report the case of a 5-year-old boy with PLACK manifestations. Whole exome sequencing and subsequent Sanger sequencing identified a putative splice variant c.1209+2T>G in CAST (NM_001042440.5). Moreover, mRNA sequencing confirmed the abnormal alternative splicing of the CAST gene, leading to the addition of one nucleotide to the correct open-reading frame at the mRNA level. Segregation and expression analysis revealed that this loss-of-function via mRNA nonsense-mediated decay could be the causative pathogenic mechanism responsible for this patient's phenotype. This study extends our understanding of the various phenotypic and genotypic features of PLACK syndrome.

Ferula gummosa gum exerts cytotoxic effects against human malignant glioblastoma multiforme in vitro.

Background and purpose: Ferula gummosa (F. gummosa), a potent medicinal herb, has been shown to possess anticancer activities in vitro. The present examination evaluated the cytotoxic and apoptogenic impacts of F. gummosa gum on the U87 glioblastoma cells. Experimental approach: MTT assay to determine the cell viability, flow cytometry by annexin V/FITC-PI to apoptosis evaluation, reactive oxygen species (ROS) assay, and quantitative RT-PCR were performed. Findings / Results: The results revealed that F. gummosa inhibited the growth of U87 cells in a concentration- and time-dependent manner with IC50 values of 115, 82, and 52 µg/mL obtained for 24, 48, and 72 h post-treatment, respectively. It was also identified that ROS levels significantly decreased following 4, 12, and 24 h after treatment. The outcomes of flow cytometry analysis suggested that F. gummosa induced a sub-G1 peak which translated to apoptosis in a concentration-dependent manner. Further examination revealed that F. gummosa upregulated Bax/Bcl-2 ratio and p53 genes at mRNA levels. Conclusion and implications: Collectively, these findings indicate that sub-G1 apoptosis and its related genes may participate in the cytotoxicity of F. gummosa gum in U87 cells.

Data mining of bulk and single-cell RNA sequencing introduces OBI1-AS1 as an astrocyte marker with possible role in glioma recurrence and progression.

Long non-coding RNAs (LncRNAs) are widely known for their various functions in cancer from tumor initiation to tumor progression and metastasis. Gliomas are the most prevalent primary forms of brain tumor, classified into grades I to IV according to their malignant histological features with grade IV, also known as glioblastoma multiforme (GBM), displaying the highest level of malignancy. Thus, the search for differentially expressed LncRNAs in GBM versus low-grade glioma to uncover new insights into the molecular mechanisms of glioma progression have intensified. Bulk RNA sequencing pinpointed decreased expression of OBI1-AS1 in GBM compared to low-grade glioma samples. Subsequent single nuclei RNA sequencing revealed OBI1-AS1 to be a super-exclusive astrocyte marker with AUC = 0.99 and the potential to fully differentiate astrocytes from other brain cell types. Additional supplementary bioinformatics analysis exhibited OBI1-AS1 role in synaptic signal transduction and glutamatergic signaling. In addition, ChIP-Seq data were analyzed to explore transcription factors that can regulate OBI1-AS1 expression in neural cells. Results of Hi-C, methylation and ChIP-Seq analysis strongly suggest methylation of the CTCF binding site serving a central role in regulation of OBI1-AS1 expression via managing chromatin interactions. Our study indicated that lncRNAs, like OBI1-AS1, could be extremely precise in identifying the astrocyte cluster in the single-cell transcriptome and demonstrating superiority to well-established astrocyte markers such as GFAP, S100B, ALDH1L1, and AQP4.

Differential Expression of Hypoxia-Related Genes in Primary Brain Tumors and Correlation with Clinicopathologic Data.

OBJECTIVE: Meningiomas and gliomas are common benign and malignant primary brain tumors, respectively. One of the most prominent features of aggressive malignancies contributing to their progression is their ability to cope with hypoxia. Therefore, glioma tumors are expected to better cope with adverse hypoxic conditions and, consequently, display significantly different expression levels of hypoxia-adaptive genes. METHODS: Thirty-three glioma (17 glioblastoma multiforme [GBM], 16 low-grade glioma [LGG]) and 32 meningioma samples were investigated for expression of hypoxia adaptation- related genes by real-time polymerase chain reaction. The same investigation was carried out for GBM, the most malignant form of glioma, versus LGG. The findings were further checked by bioinformatics analysis of expression levels using RNA-seq data. Additional investigations conducted include receiver operating characteristic curve analysis to assess the power for each gene in differential diagnosis of glioma from meningioma. RESULTS: A greater level of hypoxia-inducible factor (HIF) 1α expression in glioma samples compared with meningioma and greater expression levels of Yes-associated protein (YAP) 1 and G-protein-coupled receptor class C group 5 member A (GPRC5A) in meningioma were observed, with P values 0.0005, <0.0001, and <0.0001 for GPRC5A, HIF1α, and YAP1, respectively. Comparison of GBM with LGG also revealed GPRC5A to have significantly greater expression in GBM with P = 0.0381. The calculated area under the curve was 0.7536, 0.8438, and 0.8272 for GPRC5A, HIF1α, and YAP1, respectively, which represented acceptable power for these genes in differential diagnosis of glioma tumor types from meningioma and tumor subtypes GBM from LGG under study. CONCLUSIONS: These results imply that these genes can possibly be implicated in brain tumor hypoxia-adaptation response with tumor-specific roles and patterns of expression.

Antitumor Effects of 5-Aminolevulinic Acid on Human Malignant Glioblastoma Cells.

5-Aminolevulinic acid (5-ALA) is a naturally occurring non-proteinogenic amino acid, which contributes to the diagnosis and therapeutic approaches of various cancers, including glioblastoma (GBM). In the present study, we aimed to investigate whether 5-ALA exerted cytotoxic effects on GBM cells. We assessed cell viability, apoptosis rate, mRNA expressions of various apoptosis-related genes, generation of reactive oxygen species (ROS), and migration ability of the human U-87 malignant GBM cell line (U87MG) treated with 5-ALA at different doses. The half-maximal inhibitory concentration of 5-ALA on U87MG cells was 500 µg/mL after 7 days; 5-ALA was not toxic for human optic cells and NIH-3T3 cells at this concentration. The application of 5-ALA led to a significant increase in apoptotic cells, enhancement of Bax and p53 expressions, reduction in Bcl-2 expression, and an increase in ROS generation. Furthermore, the application of 5-ALA increased the accumulation of U87MG cells in the SUB-G1 population, decreased the expression of cyclin D1, and reduced the migration ability of U87MG cells. Our data indicate the potential cytotoxic effects of 5-ALA on U87MG cells. Further studies are required to determine the spectrum of the antitumor activity of 5-ALA on GBM.

Cross-talk between non-coding RNAs and PI3K/AKT/mTOR pathway in colorectal cancer.

Colorectal cancer (CRC) is the third commonest cancer globally, with metastasis being the reason for cancer-associated mortality. Much is still unknown biochemically about CRC, and with current treatments that are not wholly effective over time, new therapeutics are urgently needed. Emerging evidence has shown the importance of non-coding RNAs such as lncRNAs and miRNAs functions in the development and progression of CRC. However, the exact underlying mechanism of these types of RNAs in CRC is still mostly unknown. PI3K/AKT/mTOR pathway contributes to many cellular processes, and dysregulation of this pathway frequently occurs in cancers. In this review, the authors have mostly focused on the significant non-coding RNAs regulators of the PI3K/AKT/mTOR pathway and their contribution to the development or inhibition of CRC and their potential as diagnostic or therapeutic targets in CRC treatment.

Targeting the PD-1/PD-L1 pathway in glioblastoma multiforme: Preclinical evidence and clinical interventions.

Glioblastoma multiforme (GBM), as one of the immunosuppressive and common intrinsic brain tumors in adults, remains an intractable malignancy to manage. Since the standard of care for treatment, which includes surgery and chemoradiation, has not provided a sustainable and durable response in affected patients, seeking novel therapeutic approaches to treat GBM seems imperative. Immunotherapy, a breakthrough for cancer treatment, has become an attractive tool for combating cancer with the potential to access the blood-brain-barrier (BBB). In this regard, programmed cell death-1 (PD-1)/programmed cell death ligand-1 (PD-L1), as major immunological checkpoints, have drawn considerable interest due to their effectiveness in a spectrum of highly-aggressive neoplasms through negative regulation of the T-cell-mediated immune response. Nevertheless, due to the immunosuppressive microenvironment of GBM, the efficacy of these immune checkpoint inhibitors (ICIs), when used as monotherapy, has been unfavorable and lacks sufficient beneficial outcomes for GBM patients. A variety of clinical studies are attempting to evaluate the combination of ICIs (neoadjuvant/adjuvant) and existing treatment guidelines to strengthen their effectiveness; however, the exact mechanism of this signaling axis affects the consequences of immune therapy remains elusive. This review provides an overview of the PD-1/PD-L1 pathway, currently approved ICIs for clinical use, preclinical and clinical trials of PD-1/PD-L1 as monotherapy, and when used concomitantly with other GBM treatments.

Natural products as promising targets in glioblastoma multiforme: a focus on NF-κB signaling pathway.

BACKGROUND: Glioblastoma multiforme (GBM), as the broadest cerebrum tumor, is resistant to current medical interventions, particularly chemo/radiation. Hence, it necessitates further therapeutic options that could enhance the efficacy of existing modalities. METHODS: A comprehensive and systematic review of literature on the NF-κB signaling pathway-contributed in the pathogenesis of GBM with a focus on natural products was carried out. RESULTS: Several examinations have shown that nuclear factor (NF)-κB is participated in apoptosis, cellular proliferation, angiogenesis, metastasis, invasion, and many other processes implicated in GBM pathobiology. Recent studies have provided that NF-κB regulation is the primary pharmacological target for GBM therapy. Specific natural products are involved in several signaling pathways implicated in tumor growth and apoptosis of GBM cells. CONCLUSION: In the current review, we elaborate on the role of NF-κB as a promising target in GBM and discuss some natural products affecting the NF-κB signaling pathway.