Patient-Derived Non-Muscular Invasive Bladder Cancer Xenografts of Main Molecular Subtypes of the Tumor for Anti-Pd-l1 Treatment Assessment

Abstract

Background: Establishment of heterotopic patient-derived xenografts of primary and relapsed non-muscular invasive bladder cancer (NMIBC) to explore the biological property of PD-L1 signaling that may impact bladder tumor growth in humanized animals. Methods: Tumor cells of luminal, basal, and p53 subtypes of primary and relapsed NMIBC were engrafted to irradiated (3.5 Gy) NOG/SCID female mice along with intraperitoneal transplantation of human lymphocytes (5 × 107 cells/mouse); a role of PD-L1 signaling pathway inhibition for bladder cancer growth was assessed in humanized animals that carried PD-L1-expressing main molecular subtypes of bladder carcinoma patient-derived xenografts (PDX) and provided with selective anti-PD-L1 treatment. We used two-tailed Student’s t test to explore differences between main and control subgroups. Significance of intergroup comparison was measured with one-way ANOVA followed by the Tukey’s or Newman–Keul’s criterion. Survival curves were analyzed with the Gehan’s criterion with the Yate’s correction. The Spearman’s correlation was used to assess the link between CD8+ expression and sPD-L1 serum level. Differences were considered statistically significant at p < 0.05. Results: Heterotopic primary and relapsed luminal, basal, and p53 subtypes of NMIBC PDXs were established. More than 25% of counted tumor cells of all PDX specimens expressed PD-L1, so the tumors were ranged as PD-L1 positive. Anti-PD-L1 intervention increased survival of the animals that carried both primary and relapsed luminal noninvasive, muscular invasive, and relapsed luminal bladder cancer xenografts. There was significant retardation of tumor volume duplication time in aforementioned subgroups correlated with PD-L1 expression. Bad response of p53 mutant subtypes of NMIBC on specific anti-PD-L1 treatment may be associated with low CD8+ cells representation into the tumors tissue. Conclusions: Established PD-L1-positive NMIBC PDXs differently replied on anti-PD-L1 treatment due to both NMIBC molecular subtype and tumor T-suppressors population. The results may have major implications for further clinical investigations.

Patient-Derived Xenograft Models in Urological Malignancies: Urothelial Cell Carcinoma and Renal Cell Carcinoma

“…In their study, the mice did not reject the engrafted tumors and demonstrated the efficacy of pembrolizumab in CD8+ T-cell mediated tumor growth inhibition [81]. Blinova et al used humanized NSG mice to test PDL-1 blocker durvalumab and demonstrated PDL-1 expression in PDX models with significant stagnation of tumor growth [73]. It is hoped that further development of humanized mouse PDX models will allow for the study of the interaction of the tumor and the human immune system, as early models suggest that both therapeutic outcomes and side effects can be recapitulated [82].…”

Patient-Derived Urothelial Cancer Xenograft Models: A Systematic Review and Future Perspectives

“…It is not yet clear what caused it, and further investigation is needed. Blinoba et al also created NOG / SCID mice transplanted with UC PDX and human lymphocytes from healthy donors at the same time and verified the effect of anti-PD-L1 antibody [10].…”

“…On the other hand, the low success rate of PDX grafting, the long time required for their establishment, as well as their inability to serve as an evaluation model for immunotherapy have been considered as real deficiencies of PDX models for biological, translational, and pre-clinical UC research. However, the development of new immunodeficient mice has improved the rate of success grafting, and the advent of humanized mice is expected to enable reproduction of the local immunity [9,10]. Recent advances in threedimensional (3D) culture methods have also compensated for some of the deficiencies of the PDX model.…”

Immunotherapies and Metastatic Cancers: Understanding Utility and Predictivity of Human Immune Cell Engrafted Mice in Preclinical Drug Development

“…In order to improve models where immunotherapies could be tested against bladder cancer and metastasis, Blinova and colleagues established subcutaneous PDX models of basal, luminal and p53 subtypes of primary and relapsed non-muscle invasive bladder cancer (NMIBC) in human lymphocyte transplanted mice [100]. All models that expressed PD-L1 developed lung metastases from primary tumors and the formation of metastases in all molecular subtypes of human primary and relapsed NMIBCs could be inhibited by treatment with the anti-PD-L1 antibody durvalumab.…”