H3K27me3 in Diffuse Midline Glioma and Epithelial Ovarian Cancer: Opposing Epigenetic Changes Leading to the Same Poor Outcomes

The role of histone post-translational modifications in cancer and cancer immunity: functions, mechanisms and therapeutic implications

Histones play crucial roles in both promoting and repressing gene expression, primarily regulated through post-translational modifications (PTMs) at specific amino acid residues. Histone PTMs, including methylation, acetylation, ubiquitination, phosphorylation, lactylation, butyrylation, and propionylation, act as important epigenetic markers. These modifications influence not only chromatin compaction but also gene expression. Their importance extends to the treatment and prevention of various human diseases, particularly cancer, due to their involvement in key cellular processes. Abnormal histone modifications and the enzymes responsible for these alterations often serve as critical drivers in tumor cell proliferation, invasion, apoptosis, and stemness. This review introduces key histone PTMs and the enzymes responsible for these modifications, examining their impact on tumorigenesis and cancer progression. Furthermore, it explores therapeutic strategies targeting histone PTMs and offers recommendations for identifying new potential therapeutic targets.

Epigenetic regulation in ovarian cancer

Ovarian cancer is one of the diseases that have the highest mortality rate for women, especially women over 50 years old. In the future, incidence and mortality rates are predicted to extend in countries with low HDI. Instability in the structure and function of genetic factors has long been known as a cause of cancer, including ovarian cancer. Besides understanding gene mutations, epigenetic alterations have emerged as another aspect leading to the pathogenesis of ovarian neoplasm. The development and progression of this fatal disease have been found to be associated with abnormalities of epigenetic regulation. DNA methylation, histone modification, and non-coding RNAs-based gene silencing are processes of interest in developing ovarian carcinoma and are also new targets for cancer detection or treatment.

Research progress and applications of epigenetic biomarkers in cancer

Epigenetic changes are heritable changes in gene expression without changes in the nucleotide sequence of genes. Epigenetic changes play an important role in the development of cancer and in the process of malignancy metastasis. Previous studies have shown that abnormal epigenetic changes can be used as biomarkers for disease status and disease prediction. The reversibility and controllability of epigenetic modification changes also provide new strategies for early disease prevention and treatment. In addition, corresponding drug development has also reached the clinical stage. In this paper, we will discuss the recent progress and application status of tumor epigenetic biomarkers from three perspectives: DNA methylation, non-coding RNA, and histone modification, in order to provide new opportunities for additional tumor research and applications.

Lamin A K97E leads to NF-κB-mediated dysfunction of inflammatory responses in dilated cardiomyopathy

BACKGROUND INFORMATION

Lamins are type V intermediate filament proteins underlying the inner nuclear membrane which provide structural rigidity to the nucleus, tether the chromosomes, maintain nuclear homeostasis, and remain dynamically associated with developmentally regulated regions of the genome. A large number of mutations particularly in the LMNA gene encoding lamin A/C results in a wide array of human diseases, collectively termed as laminopathies. Dilated Cardiomyopathy (DCM) is one such laminopathic cardiovascular disease which is associated with systolic dysfunction of left or both ventricles leading to cardiac arrhythmia which ultimately culminates into myocardial infarction.

RESULTS

In this work, we have unraveled the epigenetic landscape to address the regulation of gene expression in mouse myoblast cell line in the context of the missense mutation LMNA 289A

CONCLUSIONS

We report here for the first time that there is a significant downregulation of the NF-κB pathway, which has been implicated in cardio-protection elsewhere.

SIGNIFICANCE

This provides a new pathophysiological explanation that correlates an LMNA mutation and dilated cardiomyopathy.

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Key Words

• NF‐κB signaling
• dilated cardiomyopathy
• epigenetic modifications
• interleukins
• lamin A

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MESH Headings

• Mice
• Animals
• Humans
• Cardiomyopathy, Dilated/genetics
• Cardiomyopathy, Dilated/metabolism
• Lamin Type A/genetics
• Lamin Type A/chemistry
• Lamin Type A/metabolism
• NF-kappa B/genetics
• NF-kappa B/metabolism
• Mutation
• Nuclear Lamina

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Grants

• Department of Atomic Energy, Government of India

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Affiliation(s)

Duhita Sengupta Biophysics and Structural Genomics Division, Saha Institute of Nuclear Physics, Kolkata, India Homi Bhabha National Institute (HBNI), Mumbai, India
Kaushik Sengupta Biophysics and Structural Genomics Division, Saha Institute of Nuclear Physics, Kolkata, India Homi Bhabha National Institute (HBNI), Mumbai, India

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Antitumoral Potential of the Histone Demethylase Inhibitor GSK-J4 in Retinoblastoma

Purpose

The purpose of this study was to investigate the antitumor effects of GSK-J4 on retinoblastoma, as well as its related biological functions and molecular mechanisms.

Methods

The antitumor effect of GSK-J4 on retinoblastoma was evaluated by in vitro and in vivo assays. CCK-8, EdU incorporation, and soft agar colony formation assays were performed to examine the effect of GSK-J4 on cell proliferation. Flow cytometry was used to evaluate the effect of GSK-J4 on the cell cycle and apoptosis. RNA-seq and Western blotting were conducted to explore the molecular mechanisms of GSK-J4. An orthotopic xenograft model was established to determine the effect of GSK-J4 on tumor growth.

Results

GSK-J4 significantly inhibited retinoblastoma cell proliferation both in vitro and in vivo, arrested the cell cycle at G2/M phase, and induced apoptosis. Mechanistically, GSK-J4 may suppress retinoblastoma cell growth by regulating the PI3K/AKT/NF-κB signaling pathway.

Conclusions

The antitumor effects of GSK-J4 were noticeable in retinoblastoma and were at least partially mediated by PI3K/AKT/NF-κB pathway suppression. Our study provides a novel strategy for the treatment of retinoblastoma.

The Ovary-Brain Connection

The brain and the ovaries are in a state of continuous communication [...].

Epigenetic Alteration of H3K27me3 as a Possible Oncogenic Mechanism of Central Neurocytoma

Central neurocytoma (CN) is a low-grade neuronal tumor that mainly arises from the lateral ventricle (LV). This tumor remains poorly understood in the sense that no driver gene aberrations have been identified thus far. We investigated immunomarkers in fetal and adult brains and 45 supratentorial periventricular tumors to characterize the biomarkers, cell of origin, and tumorigenesis of CN. All CNs occurred in the LV. A minority involved the third ventricle, but none involved the fourth ventricle. As expected, next-generation sequencing performed using a brain-tumor-targeted gene panel in 7 CNs and whole exome sequencing in 5 CNs showed no driver mutations. Immunohistochemically, CNs were robustly positive for FGFR3 (100%), SSTR2 (92%), TTF-1 (Nkx2.1) (88%), GLUT-1 (84%), and L1CAM (76%), in addition to the well-known markers of CN, synaptophysin (100%) and NeuN (96%). TTF-1 was also positive in subependymal giant cell astrocytomas (100%, 5/5) and the pituicyte tumor family, including pituicytoma and spindle cell oncocytoma (100%, 5/5). Interestingly, 1 case of LV subependymoma (20%, 1/5) was positive for TTF-1, but all LV ependymomas were negative (0/5 positive). Because TTF-1-positive cells were detected in the medial ganglionic eminence around the foramen of Monro of the fetal brain and in the subventricular zone of the LV of the adult brain, CN may arise from subventricular TTF-1-positive cells undergoing neuronal differentiation. H3K27me3 loss was observed in all CNs and one case (20%) of LV subependymoma, suggesting that chromatin remodeling complexes or epigenetic alterations may be involved in the tumorigenesis of all CNs and some ST-subependymomas. Further studies are required to determine the exact tumorigenic mechanism of CN.

[Neuropathology of pediatric brain tumors : Implications of the 5th edition of the WHO classification of central nervous system tumors]

BACKGROUND

Already with the update of the 4th edition of the World Health Organization (WHO) classification of tumors of the central nervous system, it was pointed out that pediatric diffuse glioma do not follow the same molecular mechanisms used to characterize adult diffuse glioma.

OBJECTIVES

What changes result from the update of the classification of tumors of the central nervous system?

METHODS

With the 5th edition of the WHO classification of tumors of the central nervous system, a second level of information containing molecular changes besides the histological characterization and grading of tumors was established.

RESULTS

A new classification of diffuse pediatric brain tumors based on molecular tumor pathways was established. The most important tumor pathways, considered for the new classification, were the activation of receptor tyrosine kinases and histone H3 alterations that cause epigenetic changes.

CONCLUSIONS

Increasingly better understanding of mechanisms in the development of pediatric brain tumors gives hope for more specific therapeutic approaches.

Adult spinal cord diffuse midline glioma, H3 K27-altered mimics symptoms of central nervous system infection: a case report

Diffuse midline gliomas, H3 K27-altered are infiltrative growth gliomas with histone H3K27M mutations. This glioma is more common in the pediatric population, and the prognosis is usually poor. We report a case of diffuse midline gliomas, H3 K27-altered in an adult patient that mimicked symptoms of central nervous system infection. The patient was admitted due to double vision for 2 months and paroxysmal unconsciousness for 6 days. Initially, lumbar puncture showed persistent high intracranial pressure, high protein, and low chlorine. Magnetic resonance imaging showed diffuse thickening and enhancement of meninges and spinal meninges, and later, fever occurred. The initial diagnosis was meningitis. We suspected central nervous system infection, so we started anti-infection treatment, but the treatment was ineffective. The patient's condition gradually worsened, with lower limb weakness and even the consciousness became unclear. A repeat magnetic resonance imaging and positron emission tomography-computed tomography scan showed space-occupying lesions in the spinal cord, which was considered a tumor. Following neurosurgery, pathological tests identified the tumor as diffuse midline gliomas, H3 K27-altered. The patient was recommended for radiotherapy and temozolomide chemotherapy. The patient's condition improved after chemotherapy treatment, and he survived for an additional 6 months. Our case shows that diagnosing diffuse midline gliomas, H3 K27-altered in the central nervous system is complex and can be confused with the clinical characteristics of central nervous system infection. Therefore, clinicians should pay attention to such diseases to avoid misdiagnosis.