SOX transcription factors and glioma stem cells:Choosing between stemness and differentiation

Glioblastoma(GBM)is the most common,most aggressive and deadliest brain tumor.Recently,remarkable progress has been made towards understanding the cellular and molecular biology of gliomas.GBM tumor initiation,progression and relapse as well as resistance to treatments are associated with glioma stem cells(GSCs).GSCs exhibit a high proliferation rate and self-renewal capacity and the ability to differentiate into diverse cell types,generating a range of distinct cell types within the tumor,leading to cellular heterogeneity.GBM tumors may contain different subsets of GSCs,and some of them may adopt a quiescent state that protects them against chemotherapy and radiotherapy.GSCs enriched in recurrent gliomas acquire more aggressive and therapy-resistant properties,making them more malignant,able to rapidly spread.The impact of SOX transcription factors(TFs)on brain tumors has been extensively studied in the last decade.Almost all SOX genes are expressed in GBM,and their expression levels are associated with patient prognosis and survival.Numerous SOX TFs are involved in the maintenance of the stemness of GSCs or play a role in the initiation of GSC differentiation.The fine-tuning of SOX gene expression levels controls the balance between cell stemness and differentiation.Therefore,innovative therapies targeting SOX TFs are emerging as promising tools for combatting GBM.Combatting GBM has been a demanding and challenging goal for decades.The current therapeutic strategies have not yet provided a cure for GBM and have only resulted in a slight improvement in patient survival.Novel approaches will require the fine adjustment of multimodal therapeutic strategies that simultaneously target numerous hallmarks of cancer cells to win the battle against GBM.

Influence of Sox protein SUMOylation on neural development and regeneration

SRY-related HMG-box(Sox) transcription factors are known to regulate central nervous system development and are involved in several neurological diseases.Post-translational modification of Sox proteins is known to alter their functions in the central nervous system.Among the different types of post-translational modification,small ubiquitin-like modifier(SUMO) modification of Sox proteins has been shown to modify their transcriptional activity.Here,we review the mechanisms of three Sox proteins in neuronal development and disease,along with their transcriptional changes under SUMOylation.Across three species,lysine is the conserved residue for SUMOylation.In Drosophila,SUMOylation of Sox N plays a repressive role in transcriptional activity,which impairs central nervous system development.However,de SUMOylation of Sox E and Sox11 plays neuroprotective roles,which promote neural crest precursor formation in Xenopus and retinal ganglion cell differentiation as well as axon regeneration in the rodent.We further discuss a potential translational therapy by SUMO site modification using AAV gene transduction and Clustered regularly interspaced short palindromic repeats-Cas9 technology.Understanding the underlying mechanisms of Sox SUMOylation,especially in the rodent system,may provide a therapeutic strategy to address issues associated with neuronal development and neurodegeneration.

SOX5 Regulates Cell Proliferation, Apoptosis, Migration and Invasion in KSHV-Infected Cells

Kaposi's sarcoma(KS) originates from vascular endothelial cells, with KS-associated herpesvirus(KSHV) as the etiological agent. SRY-box transcription factor 5(SOX5) plays different roles in various types of cancer, although its role in KS remains poorly understood. In this study, we identified the role of SOX5 in KS tissues and KSHV-infected cells and elucidated the molecular mechanism. Thirty-two KS patients were enrolled in this study. Measurement of SOX5 m RNA and protein levels in human KS tissues and adjacent control tissues revealed lower levels in KS tissues, with KS patients having higher SOX5 level in the early stages of the disease compared to the later stages. And SOX5 m RNA and protein was also lower in KSHV-infected cells(iSLK-219 and iSLK-BAC) than normal cells(iSLK-Puro). Additionally, SOX5 overexpression inhibited cell proliferation and promoted apoptosis and decreased KSHV-infected cell migration and invasion. Moreover, we found that SOX5 overexpression suppressed the epithelial-to-mesenchymal transition of KSHV-infected cells. These results suggest SOX5 is a suppressor factor during KS development and a potential target for KS treatment.