Alpha 1-antichymotrypsin contributes to stem cell characteristics and enhances tumorigenicity of glioblastoma

Abstract

Background Glioblastomas (GBMs) are the most common primary brains tumors in adults with almost 100% recurrence rate. Patients with lateral ventricle proximal GBMs (LV-GBMs) exhibit worse survival compared to distal locations for reasons that remain unknown. One potential explanation is the proximity of these tumors to the cerebrospinal fluid (CSF) and its contained chemical cues that can regulate cellular migration and differentiation. We therefore investigated the role of CSF on GBM gene expression and the role of a CSF-induced gene, SERPINA3, in GBM malignancy in vitro and in vivo. Methods We utilized patient-derived CSF and primary cultures of GBM brain tumor initiating cells (BTICs). We determined the impact of SERPINA3 expression in glioma patients using TCGA database. SERPINA3 expression changes were evaluated at both the mRNA and protein levels. The effects of knockdown (KD) and overexpression (OE) of SERPINA3 on cell behavior were evaluated by transwell assay (for cell migration), and alamar blue and Ki67 (for viability and proliferation respectively). Stem cell characteristics on KD cells were evaluated by differentiation and colony formation experiments. Tumor growth was studied by intracranial and flank injections. Results GBM CSF induced a significant increase in BTIC migration accompanied by upregulation of the SERPINA3 gene. In patient samples and TCGA data we observed SERPINA3 to correlate directly with brain tumor grade and indirectly with GBM patient survival. Silencing of SERPINA3 induced a decrease in cell proliferation, migration, invasion, and stem cell characteristics, while SERPINA3 overexpression increased cell migration. In vivo, mice orthotopically-injected with SERPINA3 KD BTICs showed increased survival. Conclusions SERPINA3 plays a key role in GBM malignancy and its inhibition results in a better outcome using GBM preclinical models.

Human Cerebrospinal Fluid Modulates Pathways Promoting Glioblastoma Malignancy

“…Although hypothesizing the identity of such possible modulator candidates is fascinating, it goes beyond the scope of this study; here we have not conducted a systematic analysis of CSF molecules, and we particularly wanted to focus on the effects elicited by CSF, and the downstream targets of this interaction, on GBM cells and GBM cells behavior. The leads generated by this study are presently investigated in our laboratory, we have recently proven in details the role of SERPINA3, one of the top DEGs identified by this analysis, in enhancing GBM tumorigenesis (44).…”

“…These cytokines are involved in a variety of biological activities such as inflammation, remodeling of extracellular matrix and modulation of cell growth and differentiation via the induction of important regulator elements of these processes, such as C/EBPD, VEGF, Cyclin D1, Matrix metallopeptidase 1 (MMP1) and TIMP metallopeptidase inhibitor 1 (TIMP-1). SERPINA3, not only can be induced by cytokines through STAT3 (42), but itself could be mediating and/or enhancing the same processes as an extracellular soluble protein present in the CSF (43,44). Converging on the same pathways, we have identified the upregulation of CD44, which may be mediated by the binding of one of its ligands SPP1 (the expression of which is also induced by CSF in our study) and/or MIF (both cytokines present in the CSF), with the coincidental phosphorylation of ERK1/2, c-Jun and c-Fos.…”

Glioblastoma Proximity to the Lateral Ventricle Alters Neurogenic Cell Populations of the Subventricular Zone

“…Additionally, the SVZ contains many soluble factors which contribute to neurogenesis of SVZ NSCs that GBM cells may take advantage of. These factors may be released from the NSCs themselves or be contained within the nearby cerebrospinal fluid (CSF), ultimately contributing to GBM malignancy (40)(41)(42)(43). Our previous work has revealed several CSF-induced transcriptomic changes in primary GBM cells, including upregulation of SERPINA3, MYC, and SPP1 (40,41).…”

“…These factors may be released from the NSCs themselves or be contained within the nearby cerebrospinal fluid (CSF), ultimately contributing to GBM malignancy (40)(41)(42)(43). Our previous work has revealed several CSF-induced transcriptomic changes in primary GBM cells, including upregulation of SERPINA3, MYC, and SPP1 (40,41). Gene ontology analysis has indicated an upregulation in cell viability, movement, and migration pathways induced by CSF (40), all of which may contribute to the malignancy-promoting pathways in LV-proximal tumors.…”

Histological Studies of the Ventricular–Subventricular Zone as Neural Stem Cell and Glioma Stem Cell Niche

“…Many of the factors which are enriched in the cerebrospinal fluid or the niche itself have been proposed to attract glioblastoma cells, support their growth, or alter immune cell activity, and in turn glioma cell invasion has been noted to affect V-SVZ cell proliferation. [104][105][106] Systematic review of the effects of tumor contact with the lateral ventricles on MRI (and, by extension, with the V-SVZ niche) has demonstrated that this contact, and not contact with the SGZ, is an independent predictor of shorter progression-free and overall survival, underscoring the importance of understanding these interactions when working to improve glioblastoma treatment. [107][108][109] Studies of V-SVZ-contacting and V-SVZ-distant tumors using MRI imaging and bulk transcriptomics have not reliably identified broad differences in the profiles of these two classes, arguing that a finer dissection of areas proximal to the V-SVZ, or an approach that enables quantification of cellular-level phenotypes and spatial relationship, may be needed to understand the biological effects of this contact.…”