Neutrophil stimulation with Mycobacterium bovis bacillus Calmette-Guérin (BCG) results in the release of functional soluble TRAIL/Apo-2L

Abstract

Mycobacterium bovis bacillus CalmetteGué rin (BCG) has been used to treat bladder cancer for almost 30 years; however, the effector mechanism of the BCGinduced antitumor response remains enigmatic. Most BCG research has focused on the mononuclear-cell infiltrate, but growing evidence supports a role for neutrophils in the antitumor response. Previously, we demonstrated increased urinary tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL/ Apo-2L) levels from BCG-responsive patients compared to nonresponders. Interestingly, neutrophils isolated from the urine expressed TRAIL/Apo-2L, leading us to investigate the neutrophil response to BCG. BCG-stimulated neutrophils expressed surface-bound and released functional soluble TRAIL/Apo-2L. Whereas neither interferon ␣ (IFN-␣) nor IFN-␥ directly induced TRAIL/Apo2L expression by neutrophils, IFN-␣ did stimulate TRAIL gene transcription, and IFN-primed neutrophils contained and released more TRAIL/ Apo-2L after BCG stimulation than did unprimed neutrophils. In unstimulated neutrophils TRAIL/Apo-2L was present predominantly in the azurophilic granules and plasma-membrane-enriched/ secretory-granule fraction. Finally, we observed that killed BCG, Toll-like receptor 2 (TLR2) and TLR4 agonists, and an M tuberculosis cell-wall fraction were each capable of inducing the release of soluble TRAIL/Apo-2L from neutrophils. These results further characterize the potential role neutrophils may play in initiating the antitumor response described with BCG treatment for superficial bladder cancer. IntroductionUrothelial carcinoma of the bladder accounts for approximately 5% of all cancer deaths in humans. 1 A majority of the tumors (70%-80%) are superficial at diagnosis and, after local surgical therapy, have a high rate of local recurrence (70%) and progression (30%). Thus, patients require lifelong medical follow-up examinations with inspections of their bladders, and additional surgical resection and prophylactic treatments are typically needed in the presence of recurrence. Current treatments extend time to recurrence but do not alter disease survival. The resulting economic burden on the US health care system is enormous, reaching over $4 billion annually. Indeed, as measured on the basis of cumulative per patient cost from diagnosis until death, the cost to treat bladder cancer exceeds all other forms of human cancer.In 1921, bacillus Calmette-Guérin (BCG) was isolated from Mycobacterium bovis, a mycobacterium causing bovine tuberculosis. 2 Since 1976, BCG has been used with increasing success for the treatment of superficial bladder cancer and has become the treatment of choice for this tumor entity. 3 Despite its worldwide acceptance for the treatment of superficial bladder cancer, and many mechanistic studies performed, the antitumor effector mechanism remains incompletely defined. BCG therapy results in a massive local immune response characterized by the induced cytokine expression in the bladder tissue and urine, 4 and an influx of granulocytes and mononu...

Apoptosis mediated by lentiviral TRAIL transfer involves transduction-dependent and -independent effects

“…Thus, we conclude that apoptosis was induced in a paracrine manner by membrane-bound TRAIL. This result corresponds to previous publications characterizing the bystander effect of virally expressed TRAIL, 16 or describing that the production of relevant amounts of sTRAIL by mammalian cells involves secretion of sTRAIL from intracellular stores, 38,39 rather than shedding of the extracellular domain of TRAIL present on the plasma membrane. The analysis of TRAIL receptor expression revealed high surface levels of TRAIL-R2 and lower, but still readily detectable levels of TRAIL-R1, at all culture conditions tested.…”

Attenuated, Oncolytic, but Not Wild-Type Measles Virus Infection Has Pleiotropic Effects on Human Neutrophil Function

“…Within neutrophils, TRAIL protein is reported to be detectable in all types of granules, but it is especially abundant in azurophil granules and secretory vesicles (8,50). We demonstrated clearly that MV-Vac infection per se was associated with granule release from neutrophils.…”

“…Neutrophils are known to produce TRAIL in response to M. bovis BCG but have not previously been shown to respond in this way following viral infection. In a clinical study of the antitumor activity of in patients with bladder cancer, neutrophils were implicated in the BCG-induced antitumor response (8). This response correlated with increased levels of TRAIL in urine (9).…”

“…Other groups have also implicated microorganisms in stimulating an antitumor response by neutrophils. In a clinical study of the antitumor activity of Mycobacterium bovis bacillus Calmette-Guérin (BCG), in patients with bladder cancer, neutrophils were shown to be involved in the BCGinduced antitumor response (8). This response correlated with increased levels of TRAIL in urine (9).…”

The Calcineurin B Subunit (CnB) Is a New Ligand of Integrin αM That Mediates CnB-Induced Apo2L/TRAIL Expression in Macrophages

“…It is expressed on activated T cells, NK cells, macrophages, monocytes, dendritic cells, and neutrophils and plays important roles in tumor surveillance and defense against viral infections and many other physiological and pathological processes (35,36). In immune cells, TRAIL is induced by several pathways including the type I or II IFN-mediated JAK/STAT (37)(38)(39)(40) and TLR agonist-mediated TLR pathways (41)(42)(43). Histone deacetylase inhibitors induce TRAIL in human breast tumors via the transcription factor Sp1 (44), and proline oxidase promotes TRAIL expression via NFAT (45).…”