Page 6 - BladderCancerAbstracts

CANADIAN BLADDER CANCER FORUM 2023

Canadian Bladder Cancer Forum 2023 Meeting Abstracts – Poster

Presentations

Cite as: Canadian Bladder Cancer Forum 2023 Meeting Abstracts – Poster Presentations. Can Urol Assoc J 2023;17(3Suppl1):S4-9. http://dx.doi.org/10.5489/cuaj.8351

Oncolytic virus VSV-d51-GM-CSF as an alternative for BCG of CD8 T cells and NK cells in the bladder TME. In a spontaneous bladder
treatment in non-muscle-invasive bladder cancer cancer model (BBN-induced), we are able to control disease progression
Lauren Daniel , Kowry Sow Ndiaye , Hugo Giguère , Patrick Richard , in three (of five) animals treated by VSVd51-GMCSF, while BCG treatment
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Lee-Hwa Tai 1,2 failed or only slowed down the tumor growth.
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1 Université de Sherbrooke, QC, Canada; Centre de Recherche du CHUS
Fleurimont, Sherbrooke, QC, Canada; CHUS Fleurimont, Sherbrooke, QC, Investigating sex differences in response to bacillus Calmette-
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Canada Guérin immunotherapy in the four-core genotype murine model
Introduction: Bladder cancer is the 4 and 15 most common cancer of non-muscle-invasive bladder cancer
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in men and women, respectively. Surgical resection followed by bacil- Gwenaëlle Conseil , Priyanka Yolmo , Kartik Sachdeva , Sadaf Rahimi ,
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lus Calmette-Guérin (BCG) therapy can reduce this risk, and cystectomy Manu Rangachari , D. Robert Siemens , Madhuri Koti 1
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(bladder removal) prior to muscle invasion provides the best option for 1 Department of Biomedical and Molecular Sciences, Queen’s Cancer
survival. While these therapeutic approaches are effective in many patients, Research Institute, Kingston, ON, Canada; Faculty of Medicine, Université
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recurrences remain common and there is a lack of effective second-line Laval, Quebec City, QC, Canada
bladder-sparing therapies. This is especially true for high-risk non-muscle- Introduction: The incidence of bladder cancer is three times higher in
invasive bladder cancer (NMIBC) patients who do not respond to BCG. males compared to females. Despite the lower incidence, women gener-
Two recent therapeutic advancements, immune checkpoint inhibitors and ally present with advanced-stage disease and experience shorter progres-
localized gene therapy, have attempted to treat high-risk NMIBC patients. sion-free survival. Most patients are diagnosed with non-muscle-invasive
Despite their success in other tumor types, most treated patients have failed bladder cancer (NMIBC), for which intravesical bacillus Calmette Guérin
to respond. This is due to overall immunosuppression and the small number (BCG) immunotherapy remains the gold standard treatment. We previously
of pre-existing immune-reactive cells within the bladder tumor microenvi- demonstrated the association between increased intra-tumoral CD79a+ B
ronment (TME), which limits their beneficial effects. We have previously cells pre-treatment tumors from patients with NMIBC who exhibit early
shown an enhanced antitumor benefit of both the mouse and human ver- recurrence and progression. B cells are critical to mucosal immunity and
sions of the novel oncolytic virus VSVd51-GMCSF vs. VSVd51 in preclini- response to BCG due to their antibody-producing and antigen-presenting
cal models of bladder cancer. Moving forward from our proof-of-concept functions. It is also established that B cells exhibit a sex- and age-dependent
studies, we will study the translational potential of VSVd51-GMCSF in expansion and response to treatment.
NMIBC. We hypothesize that treatment with VSVd51-GMCSF will initiate Methods: To understand the gonadal hormonal and sex chromosome-asso-
immunogenic cell death (ICD) of bladder cancer cells and potently activate ciated differences in cancer progression and response to BCG, we used
bladder tumor-directed immune responses. the Four Core Genotype (FCG) mouse model. In this model, a male mouse
Methods/Results: In vitro, we observed that viability of human (T24, lacking the testes determining Sry gene (XY - Sry+ /XYM) is crossed with an
Chr3
TCCSUP, UMUC3, and 5637) and mouse (MB49) bladder cancer cell line XX female (XXF) mouse leading to the generation of offspring with four
is not impacted by BCG treatment, while VSV-d51-VSV-GM-CSF triggers genotypes: two gonadal males (XYM, XXM) and two gonadal females (XXF
cell death. We analyzed ICD markers (HMGB1 and Hsp90 release, ATP and XYF). Bladder carcinogenesis was induced by exposing 12-month-old
essay, and calreticulin membrane exposure) and confirmed that VSVd51- aging FCG mice to 0.05% N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN)
GMCSF treatment induces ICD while BCG does not. In a mouse model, ad libitum in drinking water. After seven weeks of continuous exposure
we compared the ability of VSVd51-GMCSF and BCG to attract effector to BBN, mice were treated with three intravesical doses of BCG at weekly
immune cells in the bladder TME of MB49-implanted mice. We dissoci- intervals. Untreated and saline treated controls were included. Systemic
ated tumors and analyzed immune cells by flow cytometry. We observed and local immune profiling was performed one week post-third BCG on
a significant increase of CD8 T cells frequency in the bladder TME (mean spleen, bone marrow, and formalin-fixed whole bladders.
± SEM: 17.88 %±4.69 of CD3+ cells in VSVd51-GMCSF-treated mice vs. Results: Hematoxylin and eosin staining of whole bladder sections revealed
20.93%±1.33 in BCG-treated mice, p<0.01, two-tailed Mann-Whitney, an overall higher immune cell infiltration and increased presence of ter-
n=5), as well as NK cells (51.20%±0.86 of CD45+CD3-cells in VSVd51- tiary lymphoid structure formation in the bladders of XXF mice compared
GMCSF-treated mice vs. 11.25%±2.03 in BCG-treated mice, p<0.05, two- to all other genotypes following chronic exposure to BBN. Multispectral
tailed Mann-Whitney). While results are significantly different between PBS flow cytometry of splenocytes and bone marrow-derived cells revealed
and VSVd51-GMCSF-treated mice, they are not between PBS and BCG- significant differences in the proportions of total and atypical B cells (ABCs)
treated mice. We also used a cohort of male mice previously treated with post-completion of BCG across the four genotypes of mice compared to
N-butyl-N-(4-hydroxybutyl)-Nitrosamyl (BBN) to induce bladder cancer the mice in BBN exposed untreated and saline treated groups.
and mimic smoking-induced bladder cancer. Animals were then treated Conclusions: Overall, these findings provide evidence for a sex-associated
with VSVd51-GMCSF or BCG when tumor size was 5–10 mm (assessed role of ABCs in mediating response to BCG. Further investigations are
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by ultrasound). In VSVd51-GMCSF-treated animals, the tumor volume can warranted to understand the mechanisms underlying ABC-associated poor
be controlled; three of five animals have a tumor size still <10 mm even if outcomes in patients who exhibit high intra-tumoral B cells in their pre-
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treatment failed for two animals, with tumor size reaching 150 mm before treatment tumors.
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euthanasia. In BCG-treated animals, two of four animals’ tumors are still
growing (reaching 50–70 mm ) but for the other two animals, tumors grew
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very fast, reaching 130–150 mm before euthanasia.
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Conclusions: BCG is not able to induce cancer death, while VSVd51-
GMCSF is. In an MB49 mouse model, BCG failed to attract effector immune
cells, while VSVd51-GMCSF treatment induced an increased proportion
S4 CUAJ • MARCH 2023 • VOLUME 17, ISSUE 3(SUPPL1) © 2023 CANADIAN UROLOGICAL ASSOCIATION