Validation of hyperthermia as an enhancer of chemotherapeutic efficacy: insights from a bladder cancer organoid model

Abstract

Objective

This study aimed to evaluate the combined efficacy of hyperthermia and chemotherapy using a bladder cancer organoid model and to explore hyperthermia-related molecular pathways.

Method

Tumor organoids were generated by embedding RT4 bladder cancer cells into Matrigel. The resulting organoids were treated with pirarubicin or gemcitabine at 37 °C or 42 °C. Proliferation was determined by Ki67 immunofluorescence staining, and apoptosis was assessed using a TdT-mediated dUTP nick end labeling (TUNEL) assay. RNA sequencing was used to identify the differentially expressed genes.

Results

Bladder cancer organoids were successfully established and exhibited robust proliferative abilities. Treatment with gemcitabine or pirarubicin under hyperthermic conditions caused pronounced structural damage to the organoids and increased cell death compared to that in the normothermically treated group. Furthermore, Ki67 labeling and TUNEL assays showed that the hyperthermia chemotherapy group showed a significantly reduced proliferation rate and high level of apoptosis. Finally, RNA sequencing revealed the IFN-γ signaling pathway to be associated with hyperthermia.

Conclusion

Overall, hyperthermia combined with chemotherapy exerted better therapeutic effects than those of normothermic chemotherapy in grade 1-2 non-muscle-invasive bladder cancer, potentially through activation of the IFN-γ-JAK-STAT pathway.

Graphical Abstract

Keywords:

• Hyperthermia chemotherapy
• NMIBC
• RT4
• organoids
• bladder cancer

Acknowledgments

We thank Suzhou OptoMedic Technologies Inc. for their equipment support.

Authors contributions

Y.X. and G.S. conceptualized the study. Experiments were conducted by Y.X. and T.Y. Organoid culture technique was guided by H.L. Manuscript drafting was done by G.S. and Y.X. Data analysis was contributed by Y.X. and P.H. Manuscript revision for substantial intellectual content was undertaken by H.Z., C.L. and H.L. All coauthors participated in manuscript editing.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

All data presented in this study can be accessed upon inquiry to the corresponding author.

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.