Intravesical Ty21a treatment of non-muscle invasive bladder cancer induces immune responses that correlate with safety and may be associated to therapy potential

BACKGROUND

Standard of care treatment of non-muscle invasive bladder cancer (NMIBC) with intravesical Bacillus Calmette Guérin (BCG) is associated with side effects, disease recurrence/progression and supply shortages. We recently showed in a phase I trial (NCT03421236) that intravesical instillation in patients with NMIBC with the maximal tolerated dose of Ty21a/Vivotif, the oral vaccine against typhoid fever, might have a better safety profile. In the present report, we assessed the immunogenicity of intravesical Ty21a in patients of the clinical trial that had received the maximal tolerated dose and compared it with data obtained in patients that had received standard BCG.

METHODS

Urinary cytokines and immune cells of patients with NMIBC treated with intravesical instillations of Ty21a (n=13, groups A and F in NCT03421236) or with standard BCG in a concomitant observational study (n=12, UROV1) were determined by Luminex and flow cytometry, respectively. Serum anti-lipopolysaccharide Typhi antibodies and circulating Ty21a-specific T-cell responses were also determined in the Ty21a patients. Multiple comparisons of different paired variables were performed with a mixed-effect analysis, followed by Sidak post-test. Single comparisons were performed with a paired or an unpaired Student's t-test.

RESULTS

As compared with BCG, Ty21a induced lower levels of inflammatory urinary cytokines, which correlated to the milder adverse events (AEs) observed in Ty21a patients. However, both Ty21a and BCG induced a Th1 tumor environment. Peripheral Ty21a-specific T-cell responses and/or antibodies were observed in most Ty21a patients, pointing the bladder as an efficient local immune inductive site. Besides, Ty21a-mediated stimulation of unconventional Vδ2 T cells was also observed, which turned out more efficient than BCG. Finally, few Ty21a instillations were sufficient for increasing urinary infiltration of dendritic cells and T cells, which were previously associated with therapeutic efficacy in the orthotopic mouse model of NMIBC.

CONCLUSIONS

Ty21a immunotherapy of patient with NMIBC is promising with fewer inflammatory cytokines and mild AE, but induction of immune responses with possible antitumor potentials. Future phase II clinical trials are necessary to explore possible efficacy of intravesical Ty21a.

Intravesical Ty21a Treatment of Non-muscle-invasive Bladder Cancer Shows a Good Safety Profile

Standard-of-care immunotherapy for non–muscle-invasive bladder cancer (NMIBC) with intravesical Bacillus Calmettte-Guérin (BCG) is associated with adverse events (AEs), disease recurrence/progression, and supply shortages. Preclinical data have shown that intravesical instillation of Ty21a/Vivotif, the oral vaccine against typhoid fever, may be an effective and safer alternative to BCG. We assessed the safety of intravesical Ty21a in NMIBC. For ethical reasons, patients with low- or intermediate-risk NMIBC not requiring BCG immunotherapy were enrolled. To determine the maximum tolerated dose, escalating doses of Ty21a/Vivotif were intravesically instilled in three patients once a week for 4 wk in phase 1a. In phase 1b, ten patients received the selected dose (1 × 10⁸ CFU) once a week for 6 wk, as for standard BCG therapy. At this dose, all patients completed their treatment. Most patients experienced minor systemic AEs, while half reported mild local bladder AEs. AEs only occurred after one or two instillations for 40% of the patients. Ty21a bacteria were only recovered in three out of 72 urinary samples at 1 wk after instillation. Intravesical Ty21a might be well tolerated with no cumulative side effects, no fever >39 °C, and lower risk of bacterial persistence than with BCG. Ty21a treatment thus warrants clinical trials to explore its safety and antitumor efficacy in high-risk NMIBC. This trial is registered on ClinicalTrials.gov as NCT03421236.

Patient summary

We examined the safety of a new intra-bladder immunotherapy for non–muscle-invasive bladder cancer as an alternative to the standard BCG treatment. Our data show that the Ty21a vaccine might be well tolerated. Further studies are needed to determine the safety and antitumor efficacy of this treatment.

Vδ2 T cells are associated with favorable clinical outcomes in patients with bladder cancer and their tumor reactivity can be boosted by BCG and zoledronate treatments

Background Bladder cancer is an important public health concern due to its prevalence, high risk of recurrence and associated cost of management. Although BCG instillation for urothelial cancer treatment is the gold-standard treatment for this indication, repeated BCG treatments are associated with significant toxicity and failure, underlining the necessity for alternative or complementary immunotherapy and overall for better understanding of T-cell responses generated within bladder mucosa. Tumor-infiltrating lymphocytes (TIL) have long been recognized as a crucial component of the tumor microenvironment for the control of tumor. Among TIL, unconventional γδ T cells sparked interest due to their potent antitumor functions. Although preclinical mouse xenograft models demonstrated the relevance of using γδ T cells as a novel therapy for bladder cancer (BCa), the contribution of γδ T cells in BCa patients’ pathology remains unaddressed.

Methods Therefore, we first determined the proportion of intratumor γδ T cells in muscle-invasive patients with BCa by deconvoluting data from The Cancer Genome Atlas (TCGA) and the frequency of blood Vδ1, Vδ2, and total γδ T cells, by flow cytometry, from 80 patients with BCa (40 non-muscle and 40 muscle-invasive patients with BCa), as well as from 20 age-matched non-tumor patients. Then we investigated in vitro which treatment may promote BCa tumor cell recognition by γδ T cells.

Results We observed a decrease of γδ T-cell abundance in the tumor compared with corresponding normal adjacent tissue, suggesting that the tumor microenvironment may alter γδ T cells. Yet, high intratumor γδ T-cell proportions were significantly associated with better patient survival outcomes, potentially due to Vδ2 T cells. In the blood of patients with BCa, we observed a lower frequency of total γδ, Vδ1, and Vδ2 T cells compared with non-tumor patients, similarly to the TCGA analysis. In addition, a favorable clinical outcome is associated with a high frequency of circulating γδ T cells, which might be mainly attributed to the Vδ2 T-cell subset. Furthermore, in vitro assays revealed that either BCG, Zoledronate, or anti-BTN3 agonistic antibody treatment of bladder tumor cells induced Vδ2 T-cell cytolytic (CD107a⁺) and cytokine-production (IFN-γ and TNF-α). Strikingly, combining BCG and Zoledronate treatments significantly elicited the most quantitative and qualitative response by increasing the frequency and the polyfunctionality of bladder tumor-reactive Vδ2 T cells.

Conclusions Overall, our results suggest that (1) Vδ2 T cells might play a prominent role in bladder tumor control and (2) non-muscle invasive patients with BCa undergoing BCG therapy may benefit from Zoledronate administration by boosting Vδ2 T cells’ antitumor activity.

Siglec-7 May Limit Natural Killer Cell-mediated Antitumor responses in Bladder Cancer Patients

Aberrant glycosylation actively contributes to tumor progression and is a key hallmark of cancer. Most of the glycan moieties expressed on the surface of cancer cells are sialic acids that may modulate antitumor immune responses via binding to sialic acid–binding immunoglobulin-like lectins (Siglecs) expressed by immune cells. Here we show that Siglecs may decrease the bladder tumor immune response mediated by natural killer (NK) cells. We observed higher NK cell activity against desialylated bladder tumor cell lines. We therefore determined the expression of nine Siglecs on circulatory NK cells from healthy donors and patients with bladder cancer (BCa). NK cells from blood mainly express Siglec-7, which is highly upregulated in non–muscle-invasive BCa (NMIBC), as well as Siglec-6, albeit at a much lower level. However, both Siglecs are expressed by urinary NK cells from NMIBC patients undergoing bacillus Calmette-Guérin therapy. Ex vivo analysis of Siglec-6 and Siglec-7 expression levels on tumor-infiltrating NK cells (TINKs) from BCa patients showed that only Siglec-7 is expressed by TINKs. Finally, analyses for The Cancer Genome Atlas data set revealed that BCa patients with high expression levels of Siglec-7 have a poor survival rate. This work indicates that Siglec-7 may restrain NK-mediated antitumor immunity in BCa.

Patient summary

We investigated the expression of proteins called Siglecs in natural killer (NK) cells from patients with bladder cancer. We showed that levels of the protein Siglec-7 in blood, urine, and tumors from patients with bladder cancer are associated with poor clinical outcomes. Thus, Siglec-7 may be involved in the regulation of antitumor immunity mediated by NK cells in bladder cancer.

Hippocampal interleukin-33 mediates neuroinflammation-induced cognitive impairments

Background

Interleukin (IL)-33 is expressed in a healthy brain and plays a pivotal role in several neuropathologies, as protective or contributing to the development of cerebral diseases associated with cognitive impairments. However, the role of IL-33 in the brain is poorly understood, raising the question of its involvement in immunoregulatory mechanisms.

Methods

We administered recombinant IL-33 (rmIL-33) by intra-hippocampal injection to C57BL/6 J (WT) and IL-1αβ deficient mice. Chronic minocycline administration was performed and cognitive functions were examined trough spatial habituation test. Hippocampal inflammatory responses were investigated by RT-qPCR. The microglia activation was assessed using immunohistological staining and fluorescence-activated cell sorting (FACS).

Results

We showed that IL-33 administration in mice led to a spatial memory performance defect associated with an increase of inflammatory markers in the hippocampus while minocycline administration limited the inflammatory response. Quantitative assessment of glial cell activation in situ demonstrated an increase of proximal intersections per radius in each part of the hippocampus. Moreover, rmIL-33 significantly promoted the outgrowth of microglial processes. Fluorescence-activated cell sorting analysis on isolated microglia, revealed overexpression of IL-1β, 48 h post-rmIL-33 administration. This microglial reactivity was closely related to the onset of cognitive disturbance. Finally, we demonstrated that IL-1αβ deficient mice were resistant to cognitive disorders after intra-hippocampal IL-33 injection.

Conclusion

Thus, hippocampal IL-33 induced an inflammatory state, including IL-1β overexpression by microglia cells, being causative of the cognitive impairment. These results highlight the pathological role for IL-33 in the central nervous system, independently of a specific neuropathological model.

GM-CSF targeted immunomodulation affects host response to M. tuberculosis infection

Host directed immunomodulation represents potential new adjuvant therapies in infectious diseases such as tuberculosis. Major cytokines like TNFα exert a multifold role in host control of mycobacterial infections. GM-CSF and its receptor are over-expressed during acute M. tuberculosis infection and we asked how GM-CSF neutralization might affect host response, both in immunocompetent and in immunocompromised TNFα-deficient mice. GM-CSF neutralizing antibodies, at a dose effectively preventing acute lung inflammation, did not affect M. tuberculosis bacterial burden, but increased the number of granuloma in wild-type mice. We next assessed whether GM-CSF neutralization might affect the control of M. tuberculosis by isoniazid/rifampicin chemotherapy. GM-CSF neutralization compromised the bacterial control under sub-optimal isoniazid/rifampicin treatment in TNFα-deficient mice, leading to exacerbated lung inflammation with necrotic granulomatous structures and high numbers of intracellular M. tuberculosis bacilli. In vitro, GM-CSF neutralization promoted M2 anti-inflammatory phenotype in M. bovis BCG infected macrophages, with reduced mycobactericidal NO production and higher intracellular M. bovis BCG burden. Thus, GM-CSF pathway overexpression during acute M. tuberculosis infection contributes to an efficient M1 response, and interfering with GM-CSF pathway in the course of infection may impair the host inflammatory response against M. tuberculosis.

The cGAS/STING Pathway Is Important for Dendritic Cell Activation but Is Not Essential to Induce Protective Immunity against Mycobacterium tuberculosis Infection

Mycobacterium tuberculosis (Mtb) infection remains a major public health concern. The STING (stimulator of interferon genes) pathway contributes to the cytosolic surveillance of host cells. Most studies on the role of STING activation in Mtb infection have focused on macrophages. Moreover, a detailed investigation of the role of STING during Mtb infection in vivo is required. Here, we deciphered the involvement of STING in the activation of dendritic cells (DCs) and the host response to Mtb infection in vivo. In DCs, this adaptor molecule was important for Ifn-β expression and IL-12 production as well as for the surface expression of the activation markers CD40 and CD86. We also documented that Mtb DNA induces STING activation in murine fibroblasts. In vivo Mtb aerogenic infection induced the upregulation of the STING and cGAS (cyclic GMP-AMP synthase) genes, and Ifn-β pulmonary expression was dependent on both sensors. However, mice deficient for STING or cGAS presented a similar outcome to wild-type controls, with no major alterations in body weight gain, bacterial burden, or survival. Lung inflammation, proinflammatory cytokine production, and inflammatory cell recruitment were similar in STING- and cGAS-deficient mice compared to wild-type controls. In summary, although the STING pathway seems to be crucial for DC activation during Mtb infection, it is dispensable for host protection in vivo.

The Emerging Roles of STING in Bacterial Infections

The STING (Stimulator of Interferon Genes) protein connects microorganism cytosolic sensing with effector functions of the host cell by sensing directly cyclic dinucleotides (CDNs), originating from pathogens or from the host upon DNA recognition. Although STING activation favors effective immune responses against viral infections, its role during bacterial diseases is controversial, ranging from protective to detrimental effects for the host. In this review, we summarize important features of the STING activation pathway and recent highlights about the role of STING in bacterial infections by Chlamydia, Listeria, Francisella, Brucella, Shigella, Salmonella, Streptococcus, and Neisseria genera, with a special focus on mycobacteria.

Bioengineered 3D Models for Studying Human Cell-Tuberculosis Interactions

In vivo animal models have intrinsic limitations for studying relationships between tuberculosis and its host and there is a need for alternative, in vitro cellular models. A microsphere-based 3D in vitro culture system of Mycobacterium tuberculosis-infected human blood mononuclear cells was reported to address specific aspects of host-pathogen interactions.