Abstract

   Glioblastoma multiforme (GBM) IDH-wildtype is the most prevalent brain
   malignancy in adults. However, molecular mechanisms, which leads to GBM
   have not been completely elucidated. Granulocyte colony-stimulating
   factor (GCSF), Granulocyte colony-stimulating factor receptor GCSFR,
   and Signal transducers and activators of transcription 3 (STAT3) have
   been involved in the occurrence and development of various cancers, but
   their role in GBM is little known. Herein, we have investigated the
   gene and protein expression of GCSF, GCSFR, and STAT3 in 21 tissue
   biopsy samples and also in tumor associated normal tissue (TANT)
   samples derived from glioblastoma patients, which revealed
   significantly differential expression of these genes. To validate our
   findings, we performed a comprehensive integrated analysis of
   transcriptomic and proteomic profiling of respective genes by
   retrieving GBM RNA-sequence data from Genome Atlas Databases. GO and
   KEGG analysis revealed enrichment in disease-related pathways, such as
   JAK/STAT pathway activation, which were associated with GBM
   progression. We further performed computational docking analysis of
   potential drug candidate Nisin against GCSF, and the results were
   validated in vitro through cytotoxic activity assay using a human
   glioblastoma cell line SF-767 in a dose-dependent manner. Our
   comprehensive analysis reveals that GCSF augments glioma progression,
   and its blockade with anticancer bacteriocin peptide Nisin can
   potentially inhibit the growth and metastasis of GBM.

   Keywords: Glioblastoma, Transcriptomic profiling, Differential gene
   expression, Anti-cancer peptides, Biomarkers

   Subject terms: Cancer, Drug discovery, Biomarkers, Oncology

Introduction

   Glioblastoma multiforme (GBM) is the most lethal malignant brain
   tumour, with a 5-year survival rate < 3% and a median survival of fewer
   than 15 months^[28]1. Glioblastoma was recently classified as CNS WHO
   grade-4 IDH wildtype diffuse glioma with microvascular-proliferation
   and/or intertumoral-necrosis^[29]2. Although immunotherapy has
   transformed cancer treatment in recent years, GBM is an immunologically
   cold tumour typically resistant to this therapy due to the development
   of immune suppression mechanisms. Various studies have explored the
   intrinsic variables involved in tumour heterogeneity and
   progression^[30]3. However, tumour microenvironment dynamics are poorly
   understood and demand extensive study exploring the role of cytokines
   in the tumour microenvironment, either promoting tumour growth or
   suppressing its malignant aspects^[31]4,[32]5. Signal transducer and
   activator of transcription 3 (STAT 3) pathway is one of five critical
   pathways disrupted in human glioblastoma. In this context, we
   hypothesized that granulocyte-colony stimulating factor (GCSF), a
   potent mitogen for various cell types, may have a role in GBM by
   regulating the phosphorylation state of STAT3^[33]6. While the exact
   mechanisms linking GCSF and STAT3 phosphorylation in GBM warrant
   further investigation, several plausible pathways can be considered.
   The ability of GCSF to phosphorylate STAT3 is consistent with its
   capacity to activate Janus kinase (JAK) family members. STAT3 is known
   to be activated by the JAK kinases when it is phosphorylated at
   tyrosine residues. The subsequent phosphorylation and dimerization of
   STAT3 following GCSF-induced JAK activation may promote STAT3 nuclear
   translocation and transcriptional activity^[34]7. The pathogenesis of
   GBM may then influence the expression of genes involved in cell
   survival, proliferation, and immune evasion^[35]8. In multiple cellular
   preferences, cytokines—including GCSF—have been found to activate