An oncogenic splice variant of PDGFRα in adult glioblastoma as a therapeutic target for selective CDK4/6 inhibitors

Electroporation Induces Unexpected Alterations in Gene Expression: A Tip for Selection of Optimal Transfection Method

Electroporation is an efficient method for nucleotide and protein transfer, and is used for clustered regularly interspaced short palindromic repeat (CRISPR)-associated protein 9 (Cas9)-mediated genome editing. In this study, we investigated the effects of electroporation on platelet-derived growth factor receptor alpha (PDGFRA) and receptor tyrosine kinase (RTK) expression in U-251 and U-87 MG cells. PDGFRA mRNA and protein expression decreased 2 days after electroporation in both cell lines, with recovery observed after 13 days in U-87 MG cells. However, in U-251 MG cells, PDGFRα expression remained suppressed, despite mRNA recovery after 13 days. Similar expression profiles were observed for lipofection in the U-251 MG cells. Comprehensive RNA sequencing confirmed electroporation-induced up- and down-regulation of RTK mRNA in U-251 MG cells 2 days post-electroporation. In contrast, recombinant adeno-associated virus (rAAV) transfected with mNeonGreen fluorescent protein or Cas9 did not affect PDGFRA, RTKs, or inflammatory cytokine expression, suggesting fewer adverse effects of rAAV on U-251 MG cells. These findings emphasize the need for adequate recovery periods following electroporation or the adoption of alternative methods, such as rAAV transfection, to ensure the accurate assessment of CRISPR-mediated gene editing outcomes.

WISP1 Inhibits Hepatocellular Carcinoma Cell Proliferation by Promoting CyclinD1 Ubiquitination and Downregulating its Expression

Background/Aims

Hepatocellular carcinoma (HCC), a leading cause of cancer-related deaths, is often linked to dysregulated cell cycle proteins. This study focuses on the role of WISP1 in modulating Cyclin D1, a key cell cycle regulator, in HCC.

Materials and Methods

The study used HCCLM3 and Hep3B cells to assess the expression of Cyclin D1 and cell proliferation following the treatment of WISP1. This was achieved through Western blot, qRT-PCR, and EdU assays. Additionally, animal studies were conducted to evaluate the effects of WISP1 treatment on Cyclin D1 expression and cell proliferation.

Results

Overexpression of WISP1 in HCC cells led to a marked decrease in Cyclin D1 protein levels and reduced cell proliferation. WISP1 influences Cyclin D1 through post-translational modifications, particularly ubiquitination and proteasomal degradation.

Conclusion

The findings revealed that WISP1’s modulation of Cyclin D1 plays a critical role in inhibiting HCC cell growth, highlighting a potential therapeutic target for HCC treatment.

Molecular diversity in isocitrate dehydrogenase-wild-type glioblastoma

In the dynamic landscape of glioblastoma, the 2021 World Health Organization Classification of Central Nervous System tumours endeavoured to establish biological homogeneity, yet isocitrate dehydrogenase-wild-type (IDH-wt) glioblastoma persists as a tapestry of clinical and molecular diversity. Intertumoural heterogeneity in IDH-wt glioblastoma presents a formidable challenge in treatment strategies. Recent strides in genetics and molecular biology have enhanced diagnostic precision, revealing distinct subtypes and invasive patterns that influence survival in patients with IDH-wt glioblastoma. Genetic and molecular biomarkers, such as the overexpression of neurofibromin 1, phosphatase and tensin homolog and/or cyclin-dependent kinase inhibitor 2A, along with specific immune cell abundance and neurotransmitters, correlate with favourable outcomes. Conversely, increased expression of epidermal growth factor receptor tyrosine kinase, platelet-derived growth factor receptor alpha and/or vascular endothelial growth factor receptor, coupled with the prevalence of glioma stem cells, tumour-associated myeloid cells, regulatory T cells and exhausted effector cells, signifies an unfavourable prognosis. The methylation status of O6-methylguanine-DNA methyltransferase and the influence of microenvironmental factors and neurotransmitters further shape treatment responses. Understanding intertumoural heterogeneity is complemented by insights into intratumoural dynamics and cellular interactions within the tumour microenvironment. Glioma stem cells and immune cell composition significantly impact progression and outcomes, emphasizing the need for personalized therapies targeting pro-tumoural signalling pathways and resistance mechanisms. A successful glioblastoma management demands biomarker identification, combination therapies and a nuanced approach considering intratumoural variability. These advancements herald a transformative era in glioblastoma comprehension and treatment.

Comprehensive review of CRISPR-based gene editing: mechanisms, challenges, and applications in cancer therapy

The CRISPR system is a revolutionary genome editing tool that has the potential to revolutionize the field of cancer research and therapy. The ability to precisely target and edit specific genetic mutations that drive the growth and spread of tumors has opened up new possibilities for the development of more effective and personalized cancer treatments. In this review, we will discuss the different CRISPR-based strategies that have been proposed for cancer therapy, including inactivating genes that drive tumor growth, enhancing the immune response to cancer cells, repairing genetic mutations that cause cancer, and delivering cancer-killing molecules directly to tumor cells. We will also summarize the current state of preclinical studies and clinical trials of CRISPR-based cancer therapy, highlighting the most promising results and the challenges that still need to be overcome. Safety and delivery are also important challenges for CRISPR-based cancer therapy to become a viable clinical option. We will discuss the challenges and limitations that need to be overcome, such as off-target effects, safety, and delivery to the tumor site. Finally, we will provide an overview of the current challenges and opportunities in the field of CRISPR-based cancer therapy and discuss future directions for research and development. The CRISPR system has the potential to change the landscape of cancer research, and this review aims to provide an overview of the current state of the field and the challenges that need to be overcome to realize this potential.

GTF2E2 downregulated by miR-340-5p inhibits the malignant progression of glioblastoma

Glioblastoma is the most common malignant tumor in the central nervous system. The general transcription factor IIE subunit beta (GTF2E2) is crucial for physiological and pathological functions, but its roles in the malignant biological function of glioma remain ambiguous. CCK-8, colony formation assays, TUNEL assays, cell migration assays, wound-healing assays, and xenograft model were established to investigate the biological functions of GTF2E2 both in vitro and in vivo. GTF2E2 was overexpressed in glioma and was associated with poor prognosis of glioma patients. Biological functions of GTF2E2 were investigated both in vitro and in vi0vo by multiple experiments. Moreover, we explored the possible mechanisms of GTF2E2. In our results, we demonstrated that GTF2E2 could be regulated by miR-340-5p directly or indirectly. CCND1 was transcriptionally affected by GTF2E2 and glioma progression was then regulated. Our data presented the overexpression of GTF2E2 in glioma and indicated the association between GTF2E2 and glioma prognosis. GTF2E2 was found to be regulated by miR-340-5p and thus affect downstream gene expressions and glioma progression. Our results indicate that GTF2E2 might be a potential target in the diagnosis and treatments of glioblastoma.

Systematic Review of Molecular Targeted Therapies for Adult-Type Diffuse Glioma: An Analysis of Clinical and Laboratory Studies

Gliomas are the most common brain tumor in adults, and molecularly targeted therapies to treat gliomas are becoming a frequent topic of investigation. The current state of molecular targeted therapy research for adult-type diffuse gliomas has yet to be characterized, particularly following the 2021 WHO guideline changes for classifying gliomas using molecular subtypes. This systematic review sought to characterize the current state of molecular target therapy research for adult-type diffuse glioma to better inform scientific progress and guide next steps in this field of study. A systematic review was conducted in accordance with PRISMA guidelines. Studies meeting inclusion criteria were queried for study design, subject (patients, human cell lines, mice, etc.), type of tumor studied, molecular target, respective molecular pathway, and details pertaining to the molecular targeted therapy-namely the modality, dose, and duration of treatment. A total of 350 studies met the inclusion criteria. A total of 52 of these were clinical studies, 190 were laboratory studies investigating existing molecular therapies, and 108 were laboratory studies investigating new molecular targets. Further, a total of 119 ongoing clinical trials are also underway, per a detailed query on clinicaltrials.gov. GBM was the predominant tumor studied in both ongoing and published clinical studies as well as in laboratory analyses. A few studies mentioned IDH-mutant astrocytomas or oligodendrogliomas. The most common molecular targets in published clinical studies and clinical trials were protein kinase pathways, followed by microenvironmental targets, immunotherapy, and cell cycle/apoptosis pathways. The most common molecular targets in laboratory studies were also protein kinase pathways; however, cell cycle/apoptosis pathways were the next most frequent target, followed by microenvironmental targets, then immunotherapy pathways, with the wnt/β-catenin pathway arising in the cohort of novel targets. In this systematic review, we examined the current evidence on molecular targeted therapy for adult-type diffuse glioma and discussed its implications for clinical practice and future research. Ultimately, published research falls broadly into three categories-clinical studies, laboratory testing of existing therapies, and laboratory identification of novel targets-and heavily centers on GBM rather than IDH-mutant astrocytoma or oligodendroglioma. Ongoing clinical trials are numerous in this area of research as well and follow a similar pattern in tumor type and targeted pathways as published clinical studies. The most common molecular targets in all study types were protein kinase pathways. Microenvironmental targets were more numerous in clinical studies, whereas cell cycle/apoptosis were more numerous in laboratory studies. Immunotherapy pathways are on the rise in all study types, and the wnt/β-catenin pathway is increasingly identified as a novel target.

Genome Editing Using Cas9 Ribonucleoprotein Is Effective for Introducing PDGFRA Variant in Cultured Human Glioblastoma Cell Lines

Many variants of uncertain significance (VUS) have been detected in clinical cancer cases using next-generation sequencing-based cancer gene panel analysis. One strategy for the elucidation of VUS is the functional analysis of cultured cancer cell lines that harbor targeted gene variants using genome editing. Genome editing is a powerful tool for creating desired gene alterations in cultured cancer cell lines. However, the efficiency of genome editing varies substantially among cell lines of interest. We performed comparative studies to determine the optimal editing conditions for the introduction of platelet-derived growth factor receptor alpha (PDGFRA) variants in human glioblastoma multiforme (GBM) cell lines. After monitoring the copy numbers of PDGFRA and the expression level of the PDGFRα protein, four GBM cell lines (U-251 MG, KNS-42, SF126, and YKG-1 cells) were selected for the study. To compare the editing efficiency in these GBM cell lines, the modes of clustered regularly interspaced short palindromic repeat (CRISPR)-associated protein 9 (Cas9) delivery (plasmid vs. ribonucleoprotein (RNP)), methods of transfection (lipofection vs. electroporation), and usefulness of cell sorting were then evaluated. Herein, we demonstrated that electroporation-mediated transfer of Cas9 with single-guide RNA (Cas9 RNP complex) could sufficiently edit a target nucleotide substitution, irrespective of cell sorting. As the Cas9 RNP complex method showed a higher editing efficiency than the Cas9 plasmid lipofection method, it was the optimal method for single-nucleotide editing in human GBM cell lines under our experimental conditions.

Molecular Genetic Profile of 300 Japanese Patients with Diffuse Gliomas Using a Glioma-tailored Gene Panel

Rapid technological advances in molecular biology, including next-generation sequencing, have identified key genetic alterations in central nervous system (CNS) tumors. Accordingly, the fifth edition of the World Health Organization (WHO) CNS tumor classification was published in 2021. We analyzed 303 patients with diffuse glioma using an amplicon-based glioma-tailored gene panel for detecting 1p/19q codeletion and driver gene mutations such as IDH1/2, TERTp, EGFR, and CDKN2A/B on a single platform. Within glioblastomas (GBMs), the most commonly mutated genes were TERTp, TP53, PTEN, NF1, and PDGFRA, which was the most frequently mutated tyrosine kinase receptor in GBM, followed by EGFR. The genes that most commonly showed evidence of loss were PTEN, CDKN2A/B, and RB1, whereas the genes that most commonly showed evidence of gain/amplification were EGFR, PDGFRA, and CDK4. In 22 grade III oligodendroglial tumors, 3 (14%) patients had CDKN2A/B homozygous deletion, and 4 (18%) patients had ARID1A mutation. In grade III oligodendroglial tumors, an ARID1A mutation was associated with worse progression-free survival. Reclassification based on the WHO 2021 classification resulted in 62.5% of grade II/III isocitrate dehydrogenase (IDH)-wildtype astrocytomas being classified as IDH-wildtype GBM and 37.5% as not elsewhere classified. In summary, our glioma-tailored gene panel was applicable for molecular diagnosis in the WHO 2021 classification. In addition, we successfully reclassified the 303 diffuse glioma cases based on the WHO 2021 classification and clarified the genetic profile of diffuse gliomas in the Japanese population.

A Novel Splice Variant of BCAS1 Inhibits β-Arrestin 2 to Promote the Proliferation and Migration of Glioblastoma Cells, and This Effect Was Blocked by Maackiain

Brain-enriched myelin-associated protein 1 (BCAS1) is frequently highly expressed in human cancer, but its detailed function is unclear. Here, we identified a novel splice variant of the BCAS1 gene in glioblastoma multiforme (GBM) named BCAS1-SV1. The expression of BCAS1-SV1 was weak in heathy brain cells but high in GBM cell lines. The overexpression of BCAS1-SV1 significantly increased the proliferation and migration of GBM cells, whereas the RNA-interference-mediated knockdown of BCAS1-SV1 reduced proliferation and migration. Moreover, using a yeast-two hybrid assay, immunoprecipitation, and immunofluorescence staining, we confirmed that β-arrestin 2 is an interaction partner of BCAS1-SV1 but not BCAS1. The downregulation of β-arrestin 2 directly enhanced the malignancy of GBM and abrogated the effects of BCAS1-SV1 on GBM cells. Finally, we used a yeast two-hybrid-based growth assay to identify that maackiain (MK) is a potential inhibitor of the interaction between BCAS1-SV1 and β-arrestin 2. MK treatment lessened the proliferation and migration of GBM cells and prolonged the lifespan of tumor-bearing mice in subcutaneous xenograft and intracranial U87-luc xenograft models. This study provides the first evidence that the gain-of-function BCAS1-SV1 splice variant promotes the development of GBM by suppressing the β-arrestin 2 pathway and opens up a new therapeutic perspective in GBM.