KR158 Spheres Harboring Slow-Cycling Cells Recapitulate High-Grade Glioma Features in an Immunocompetent System.

Glioblastoma (GBM) poses a significant challenge in clinical oncology due to its aggressive nature, heterogeneity, and resistance to therapies. Cancer stem cells (CSCs) play a critical role in GBM, particularly in treatment resistance and tumor relapse, emphasizing the need to comprehend the mechanisms regulating these cells. Also, their multifaceted contributions to the tumor microenvironment (TME) underline their significance, driven by their unique properties. This study aimed to characterize glioblastoma stem cells (GSCs), specifically slow-cycling cells (SCCs), in an immunocompetent murine GBM model to explore their similarities with their human counterparts. Using the KR158 mouse model, we confirmed that SCCs isolated from this model exhibited key traits and functional properties akin to human SCCs. KR158 murine SCCs, expanded in the gliomasphere assay, demonstrated sphere forming ability, self-renewing capacity, positive tumorigenicity, enhanced stemness and resistance to chemotherapy. Together, our findings validate the KR158 murine model as a framework to investigate GSCs and SCCs in GBM pathology, and explore specifically the SCC-immune system communications, understand their role in disease progression, and evaluate the effect of therapeutic strategies targeting these specific connections.

KR158 spheres harboring slow-cycling cells recapitulate GBM features in an immunocompetent system.

Glioblastoma (GBM) poses a significant challenge in clinical oncology due to its aggressive nature, heterogeneity, and resistance to therapies. Cancer stem cells (CSCs) play a critical role in GBM, particularly in treatment-resistance and tumor relapse, emphasizing the need to comprehend the mechanisms regulating these cells. Also, their multifaceted contributions to the tumor-microenvironment (TME) underline their significance, driven by their unique properties. This study aimed to characterize glioblastoma stem cells (GSCs), specifically slow-cycling cells (SCCs), in an immunocompetent murine GBM model to explore their similarities with their human counterparts. Using the KR158 mouse model, we confirmed that SCCs isolated from this model exhibited key traits and functional properties akin to human SCCs. KR158 murine SCCs, expanded in the gliomasphere assay, demonstrated sphere forming ability, self-renewing capacity, positive tumorigenicity, enhanced stemness and resistance to chemotherapy. Together, our findings validate the KR158 murine model as a framework to investigate GSCs and SCCs in GBM-pathology, and explore specifically the SCC-immune system communications, understand their role in disease progression, and evaluate the effect of therapeutic strategies targeting these specific connections.

Heterogeneity of glioblastoma stem cells in the context of the immune microenvironment and geospatial organization.

Glioblastoma (GBM) is an extremely aggressive and incurable primary brain tumor with a 10-year survival of just 0.71%. Cancer stem cells (CSCs) are thought to seed GBM's inevitable recurrence by evading standard of care treatment, which combines surgical resection, radiotherapy, and chemotherapy, contributing to this grim prognosis. Effective targeting of CSCs could result in insights into GBM treatment resistance and development of novel treatment paradigms. There is a major ongoing effort to characterize CSCs, understand their interactions with the tumor microenvironment, and identify ways to eliminate them. This review discusses the diversity of CSC lineages present in GBM and how this glioma stem cell (GSC) mosaicism drives global intratumoral heterogeneity constituted by complex and spatially distinct local microenvironments. We review how a tumor's diverse CSC populations orchestrate and interact with the environment, especially the immune landscape. We also discuss how to map this intricate GBM ecosystem through the lens of metabolism and immunology to find vulnerabilities and new ways to disrupt the equilibrium of the system to achieve improved disease outcome.

Transferability of ESBL-encoding IncN and IncI1 plasmids among field strains of different Salmonella serovars and Escherichia coli.

OBJECTIVES: This study aimed to sequence, assemble, and annotate three plasmids (two IncN and one IncI1) carrying the blaCTX-M-1 gene and assess their transferability rates between homologous and heterologous serovars and/or species of bacteria. METHODS: First, the plasmids were sequenced, assembled, and annotated. They were then transferred from three donor strains (Escherichia coli/IncN, S. Heidelberg/IncN, and S. Heidelberg/IncI1) into nine recipient strains (S. Enteritidis, S. Heidelberg, S. Saintpaul, S. Cero, S. Infantis, S. Braenderup, E. coli 50, and E. coli 2010). The blaCTX-M-1 gene polymerase chain reaction (PCR), plasmid isolation, and antimicrobial susceptibility testing were used on the transconjugants to confirm the successful transfer of extended-spectrum beta lactamase (EBSL) plasmids into the recipient strains. RESULTS: Both IncN plasmids were 42,407 bp in size and showed >99.4% similarity to the S. Bredeney pET1.2-IncN (GenBank accession CP043224.1), whereas the IncI1 plasmid was 107,635 bp in size and demonstrated >99.9% similarity to the E. coli pCOV33 plasmid (GenBank accession MG649046.1). Successful plasmid transfer was observed between donor ​E. coli (IncN) and all recipient strains except for E. coli 50 and between donor S. Heidelberg (IncN) and all recipient strains. Successful plasmid transfer was also observed between S. Heidelberg (IncI1) and E. coli 50. CONCLUSION: Transfer of the blaCTX-M-1 encoding IncN and IncI1 plasmids via conjugation is possible and yet occurs at different frequencies depending on the donor strain of bacteria, with S. Heidelberg (IncN) having the highest donor-dependent transfer frequency, followed by E. coli 9079 (IncN) and S. Heidelberg (IncI1).