To Become or Not to Become Tumorigenic: Subventricular Zone Versus Hippocampal Neural Stem Cells

Differential effects of antiseizure medications on neurogenesis: Evidence from cells to animals

Neurogenesis, the process of generating functionally integrated neurons from neural stem and progenitor cells, is involved in brain development during embryonic stages but continues throughout life. Adult neurogenesis plays essential roles in many brain functions such as cognition, brain plasticity, and repair. Abnormalities in neurogenesis have been described in many neuropsychiatric and neurological disorders, including epilepsy. While sharing a common property of suppressing seizures, accumulating evidence has shown that some antiseizure medications (ASM) exhibit neuroprotective potential in the non-epileptic models including Parkinson's disease, Alzheimer's disease, cerebral ischemia, or traumatic brain injury. ASM are a heterogeneous group of medications with different mechanisms of actions. Therefore, it remains to be revealed whether neurogenesis is a class effect or related to them all. In this comprehensive literature study, we reviewed the literature data on the influence of ASM on the neurogenesis process during brain development and also in the adult brain under physiological or pathological conditions. Meanwhile, we discussed the underlying mechanisms associated with the neurogenic effects of ASM by linking the reported in vivo and in vitro studies. PubMed, Web of Science, and Google Scholar databases were searched until the end of February 2023. A total of 83 studies were used finally. ASM can modulate neurogenesis through the increase or decrease of proliferation, survival, and differentiation of the quiescent NSC pool. The present article indicated that the neurogenic potential of ASM depends on the administered dose, treatment period, temporal administration of the drug, and normal or disease context.

Unmasking the Deceptive Nature of Cancer Stem Cells: The Role of CD133 in Revealing Their Secrets

Cancer remains a leading cause of death globally, and its complexity poses a significant challenge to effective treatment. Cancer stem cells and their markers have become key players in tumor growth and progression. CD133, a marker in various cancer types, is an active research area as a potential therapeutic target. This article explores the role of CD133 in cancer treatment, beginning with an overview of cancer statistics and an explanation of cancer stem cells and their markers. The rise of CD133 is discussed, including its structure, functions, and occurrence in different cancer types. Furthermore, the article covers CD133 as a therapeutic target, focusing on gene therapy, immunotherapy, and approaches to affect CD133 expression. Nanoparticles such as gold nanoparticles and nanoliposomes are also discussed in the context of CD133-targeted therapy. In conclusion, CD133 is a promising therapeutic target for cancer treatment. As research in this area progresses, it is hoped that CD133-targeted therapies will offer new and effective treatment options for cancer patients in the future.

Targeting the neural stem cells in subventricular zone for the treatment of glioblastoma: an update from preclinical evidence to clinical interventions

BACKGROUND

Glioblastoma is one of the most common and aggressive adult brain tumors. The conventional treatment strategy, surgery combined with chemoradiotherapy, did not change the fact that the recurrence rate was high and the survival rate was low. Over the years, accumulating evidence has shown that the subventricular zone has an important role in the recurrence and treatment resistance of glioblastoma. The human adult subventricular zone contains neural stem cells and glioma stem cells that are probably a part of reason for therapy resistance and recurrence of glioblastoma.

MAIN BODY

Over the years, both bench and bedside evidences strongly support the view that the presence of neural stem cells and glioma stem cells in the subventricular zone may be the crucial factor of recurrence of glioblastoma after conventional therapy. It emphasizes the necessity to explore new therapy strategies with the aim to target subventricular zone to eradicate neural stem cells or glioma stem cells. In this review, we summarize the recent preclinical and clinical advances in targeting neural stem cells in the subventricular zone for glioblastoma treatment, and clarify the prospects and challenges in clinical application.

CONCLUSIONS

Although there remain unresolved issues, current advances provide us with a lot of evidence that targeting the neural stem cells and glioma stem cells in subventricular zone may have the potential to solve the dilemma of glioblastoma recurrence and treatment resistance.

Migratory Response of Cells in Neurogenic Niches to Neuronal Death: The Onset of Harmonic Repair?

Harmonic mechanisms orchestrate neurogenesis in the healthy brain within specific neurogenic niches, which generate neurons from neural stem cells as a homeostatic mechanism. These newly generated neurons integrate into existing neuronal circuits to participate in different brain tasks. Despite the mechanisms that protect the mammalian brain, this organ is susceptible to many different types of damage that result in the loss of neuronal tissue and therefore in alterations in the functionality of the affected regions. Nevertheless, the mammalian brain has developed mechanisms to respond to these injuries, potentiating its capacity to generate new neurons from neural stem cells and altering the homeostatic processes that occur in neurogenic niches. These alterations may lead to the generation of new neurons within the damaged brain regions. Notwithstanding, the activation of these repair mechanisms, regeneration of neuronal tissue within brain injuries does not naturally occur. In this review, we discuss how the different neurogenic niches respond to different types of brain injuries, focusing on the capacity of the progenitors generated in these niches to migrate to the injured regions and activate repair mechanisms. We conclude that the search for pharmacological drugs that stimulate the migration of newly generated neurons to brain injuries may result in the development of therapies to repair the damaged brain tissue.

Glioblastoma and Methionine Addiction

Glioblastoma is a fatal brain tumor with a bleak prognosis. The use of chemotherapy, primarily the alkylating agent temozolomide, coupled with radiation and surgical resection, has provided some benefit. Despite this multipronged approach, average patient survival rarely extends beyond 18 months. Challenges to glioblastoma treatment include the identification of functional pharmacologic targets as well as identifying drugs that can cross the blood-brain barrier. To address these challenges, current research efforts are examining metabolic differences between normal and tumor cells that could be targeted. Among the metabolic differences examined to date, the apparent addiction to exogenous methionine by glioblastoma tumors is a critical factor that is not well understood and may serve as an effective therapeutic target. Others have proposed this property could be exploited by methionine dietary restriction or other approaches to reduce methionine availability. However, methionine links the tumor microenvironment with cell metabolism, epigenetic regulation, and even mitosis. Therefore methionine depletion could result in complex and potentially undesirable responses, such as aneuploidy and the aberrant expression of genes that drive tumor progression. If methionine manipulation is to be a therapeutic strategy for glioblastoma patients, it is essential that we enhance our understanding of the role of methionine in the tumor microenvironment.

Regional Development of Glioblastoma: The Anatomical Conundrum of Cancer Biology and Its Surgical Implication

Glioblastoma (GBM) are among the most common malignant central nervous system (CNS) cancers, they are relatively rare. This evidence suggests that the CNS microenvironment is naturally equipped to control proliferative cells, although, rarely, failure of this system can lead to cancer development. Moreover, the adult CNS is innately non-permissive to glioma cell invasion. Thus, glioma etiology remains largely unknown. In this review, we analyze the anatomical and biological basis of gliomagenesis considering neural stem cells, the spatiotemporal diversity of astrocytes, microglia, neurons and glutamate transporters, extracellular matrix and the peritumoral environment. The precise understanding of subpopulations constituting GBM, particularly astrocytes, is not limited to glioma stem cells (GSC) and could help in the understanding of tumor pathophysiology. The anatomical fingerprint is essential for non-invasive assessment of patients’ prognosis and correct surgical/radiotherapy planning.

The Relevance of Circadian Clocks to Stem Cell Differentiation and Cancer Progression

The molecular mechanism of circadian clocks depends on transcription-translation feedback loops (TTFLs) that have known effects on key cellular processes. However, the distinct role of circadian TTFLs in mammalian stem cells and other less differentiated cells remains poorly understood. Neural stem cells (NSCs) of the brain generate neurons and glia postnatally but also may become cancer stem cells (CSCs), particularly in astrocytomas. Evidence indicates clock TTFL impairment is needed for tumor growth and progression; although, this issue has been examined primarily in more differentiated cancer cells rather than CSCs. Similarly, few studies have examined circadian rhythms in NSCs. After decades of research, it is now well recognized that tumors consist of CSCs and a range of other cancer cells along with noncancerous stromal cells. The circadian properties of these many contributors to tumor properties and treatment outcome are being widely explored. New molecular tools and ones in development will likely enable greater discrimination of important circadian and non-circadian cells within malignancies at multiple stages of cancer progression and following therapy. Here, we focus on adult NSCs and glioma CSCs to address how cells at different stages of differentiation may harbor unique states of the molecular circadian clock influencing differentiation and cell fate.

A two-photon ratiometric fluorescent probe for real-time imaging and quantification of NO in neural stem cells during activation regulation

Developing a novel tool capable of real-time monitoring and accurate quantification of NO is critical to understanding its role in physiological and pathological processes. Herein, a two-photon ratiometric fluorescent probe (NOP) was developed for real-time imaging and quantification of NO based on fluorescence resonance energy transfer-photoinduced electron transfer (FRET-PET). In this developed probe, coumarin (CM) and naphthalimide with o-phenylenediamine (NPM) were rationally designed as a fluorescent donor and acceptor, respectively, to enable a ratiometric fluorescence response to NO. The developed NO probe demonstrated good detection linearity with the concentration of NO in the range of 0.100–200 μM, with a detection limit of 19.5 ± 1.00 nM. Considering the advantages of high selectivity, good accuracy and rapid dynamic response (<15 s), the developed NO probe was successfully applied for real-time imaging and accurate quantification of NO in neural stem cells (NSCs) and different regions of mouse brain tissue with a penetration depth of 350 μm. Using this powerful tool, it was found that NO regulated the activation and differentiation of quiescent NSCs (qNSCs). In addition, NO-induced differentiation of qNSCs into neurons was found to be dose-dependent: 50.0 μM NO caused about 50.0% of qNSCs to differentiate into neurons. Moreover, different regions of the mouse brain were observed to be closely related to the concentration of NO, and the concentration of NO in the DG region was found to be lower than that in the S1BF, CA1, LD and CPu of the Alzheimer's disease (AD) mouse brain. The symptoms of AD mice were significantly improved through the treatment with NO-activated NSCs in the DG region.

Developing a novel tool capable of real-time monitoring and accurate quantification of NO is critical to understanding its role in physiological and pathological processes.