GM-CSF x TGF-β2

Neuroendocrine prostate cancer (NEPC) is a highly aggressive and treatment-resistant subtype of castration-resistant prostate cancer (CRPC) that often emerges during progression under androgen-receptor (AR) pathway inhibition. While lineage plasticity in cancer cells has been recognized as a key mechanism of resistance, the role of the tumor microenvironment in driving this transition remains unclear. Among its cellular components, vascular endothelial cells can undergo endothelial-mesenchymal transition (EndoMT), a phenotypic shift associated with tumor progression and fibrosis. Here, we investigated whether EndoMT contributes to NEPC development. Human umbilical vein endothelial cells (HUVEC) were induced to undergo EndoMT using IL-1β and TGF-β2, and are hereafter referred to as EndoMTed HUVEC. EndoMTed HUVEC promoted neuroendocrine features and functional changes in LNCaP cells. Transcriptome analysis revealed marked upregulation of granulocyte-macrophage colony-stimulating factor (GM-CSF) in EndoMTed HUVEC. Neutralization of GM-CSF signaling using mavrilimumab, a monoclonal antibody targeting the GM-CSF receptor alpha (CSF2RA), and siRNA-mediated CSF2RA knockdown both suppressed the neuroendocrine phenotype and STAT3 signaling of LNCaP cells. Conversely, GM-CSF stimulation alone reproduced these changes. Enzalutamide-treated LNCaP cells secreted IL-1β and TGF-β2, which in turn triggered EndoMT, suggesting a reciprocal loop. These findings indicate that anti-androgen therapy may inadvertently promote NEPC through a paracrine loop involving tumor-derived cytokines and endothelial GM-CSF secretion, highlighting EndoMT as a microenvironmental driver of treatment resistance.

We describe in this review the historical evidence leading up to the concept and design of Vigil and subsequent clinical applications including safety and efficacy in a randomized, controlled Phase IIB trial. Vigil (gemogenovatucel-T) is a unique triple function targeted immunotherapy that demonstrates preclinical and clinical systemic anticancer activity. Construction of Vigil involves harvest of autologous malignant tissue for neoantigen targeting (ideally containing clonal neoantigens) followed by a two-day process involving transfection with a plasmid to provide a permissive 'training environment' for the patient's immune system. Transfected plasmid components contain an expressive human GMCSF DNA segment to enhance anticancer immune functional response and a second component expressing bi-shRNA^furin which reduces TGFβ isomers (TGFβ1 and TGFβ2) thereby reducing cancer inhibition of the targeted immune response. Results generated to date justify advancement to confirmatory clinical trials supporting product regulatory approval.

Flagellin, which is abundant in gram-negative bacteria, including Pseudomonas, is reported to influence on inflammatory responses in various lung diseases. However, its effect on airway epithelial cells in contribution to asthma pathogenesis is not elucidated yet. We aimed to investigate the effect of TLR5 ligand flagellin on the transcriptomic profile of primary human epithelial cells and to determine the markers of airway inflammation.

Normal human bronchial epithelial (NHBE) cells were grown and differentiated in air-liquid interface (ALI) culture for 14-16 days. The cells were treated with flagellin in vitro at 10 and 100 ng/ml for 3 and 24 h. The conditioned media and cells were harvested to validate inflammatory markers involved in airway inflammation using ELISA, Western blot, and quantitative PCR methods. RNA-sequencing was performed to investigate the transcriptional response to flagellin in ALI-NHBE cells.

Altered transcriptional responses to flagellin in differentiated bronchial epithelial cells were determined, including genes encoding chemokines, matrix metalloproteinases, and antimicrobial biomolecules. Pathway analysis of the transcriptionally responsive genes revealed enrichment of signaling pathways. Flagellin induced the mRNA expressions of proinflammatory cytokines and chemokines, and secretion of GM-CSF, CXCL5, CCL5 and CXCL10. Flagellin enhanced the protein expression of MMP-13 in TGF-β1 and TGF-β2 pretreated cell lysates and Wnt/β-catenin signaling.

These findings suggest that flagellin could be a potent inducer of inflammatory markers that may contribute to airway inflammation and remodeling.