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Synergy of Tumor Microenvironment Remodeling and Autophagy Inhibition to Sensitize Radiation for Bladder Cancer Treatment.

ABSTRACT: Tumor hypoxia, acidosis, and excessive reactive oxygen species (ROS) were the main characteristics of the bladder tumor microenvironment (TME), and abnormal TME led to autophagy activation, which facilitated cancer cell proliferation. The therapeutic efficacy of autophagy inhibitors might also be impeded by abnormal TME. To address these issues, we proposed a new strategy that utilized manganese dioxide (MnO2) nanoparticles to optimize the abnormal TME and revitalize autophagy inhibitors, and both oxygenation and autophagy inhibition may sensitize the tumor cells to radiation therapy. Methods: By taking advantage of the strong affinity between negatively charged MnO2 and positively charged chloroquine (CQ), the nanoparticles were fabricated by integrating MnO2 and CQ in human serum albumin (HSA)-based nanoplatform (HSA-MnO2-CQ NPs). Results: HSA-MnO2-CQ NPs NPs efficiently generated O2 and increased pH in vitro after reaction with H+/H2O2 and then released the encapsulated CQ in a H+/H2O2 concentration-dependent manner. The NPs restored the autophagy-inhibiting activity of chloroquine in acidic conditions by increasing its intracellular uptake, and markedly blocked hypoxia-induced autophagic flux. In vivo studies showed the NPs improved pharmacokinetic behavior of chloroquine and effectively accumulated in tumor tissues. The NPs exhibited significantly decreased tumor hypoxia areas and increased tumor pH, and had remarkable autophagy inhibition efficacy on bladder tumors. Finally, a significant anti-tumor effect achieved by the enhanced autophagy inhibition and radiation sensitization. Conclusions: HSA-MnO2-CQ NPs synergistically regulated the abnormal TME and inhibited autophagic flux, and effectively sensitized radiation therapy to treat bladder cancers.

SUBMITTER: Lin T

PROVIDER: S-EPMC7359086 | biostudies-literature | 2020

REPOSITORIES: biostudies-literature

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Synergy of Tumor Microenvironment Remodeling and Autophagy Inhibition to Sensitize Radiation for Bladder Cancer Treatment.

Lin Tingsheng T Zhang Qing Q Yuan Ahu A Wang Baojun B Zhang Feifei F Ding Yuanzhen Y Cao Wenmin W Chen Wei W Guo Hongqian H

Theranostics 20200619 17

Tumor hypoxia, acidosis, and excessive reactive oxygen species (ROS) were the main characteristics of the bladder tumor microenvironment (TME), and abnormal TME led to autophagy activation, which facilitated cancer cell proliferation. The therapeutic efficacy of autophagy inhibitors might also be impeded by abnormal TME. To address these issues, we proposed a new strategy that utilized manganese dioxide (MnO<sub>2</sub>) nanoparticles to optimize the abnormal TME and revitalize autophagy inhibit ...[more]

PMID: 32685013

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Project description:Intravesical BCG instillation after bladder tumor resection is the standard treatment for non-muscle invasive bladder cancer; however, it is not always effective and frequently has undesirable side effects. Therefore, new strategies that improve the clinical management of patients are urgently needed. This study aimed to comprehensively evaluate the bladder tumor immune microenvironment profile after intravesical treatment with a panel of mycobacteria with variation in their cell envelope composition and its impact on survival using an orthotopic murine model to identify more effective and safer therapeutic strategies. tumor-bearing mice were intravesically treated with a panel of BCG and M. brumae cultured under different conditions. Untreated tumor-bearing mice and healthy mice were also included as controls. After mycobacterial treatments, the infiltrating immune cell populations in the bladder were analysed by flow cytometry. We provide evidence that mycobacterial treatment triggered a strong immune infiltration into the bladder, with BCG inducing higher global absolute infiltration than M. brumae. The induced global immune microenvironment was strikingly different between the two mycobacterial species, affecting both innate and adaptive immunity. Compared with M. brumae, BCG treated mice exhibited a more robust infiltration of CD4+ and CD8+ T-cells skewed toward an effector memory phenotype, with higher frequencies of NKT cells, neutrophils/gMDSCs and monocytes, especially the inflammatory subset, and higher CD4+ TEM/CD4+ Treg and CD8+ TEM/CD4+ Treg ratios. Conversely, M. brumae treatment triggered higher proportions of total activated immune cells and activated CD4+ and CD8+ TEM cells and lower ratios of CD4+ TEM cells/CD4+ Tregs, CD8+ TEM cells/CD4+ Tregs and inflammatory/reparative monocytes. Notably, the mycobacterial cell envelope composition in M. brumae had a strong impact on the immune microenvironment, shaping the B and myeloid cell compartment and T-cell maturation profile and thus improving survival. Overall, we demonstrate that the bladder immune microenvironment induced by mycobacterial treatment is species specific and shaped by mycobacterial cell envelope composition. Therefore, the global bladder immune microenvironment can be remodelled, improving the quality of infiltrating immune cells, the balance between inflammatory and regulatory/suppressive responses and increasing survival.

Dataset Information

Synergy of Tumor Microenvironment Remodeling and Autophagy Inhibition to Sensitize Radiation for Bladder Cancer Treatment.

Publications

Synergy of Tumor Microenvironment Remodeling and Autophagy Inhibition to Sensitize Radiation for Bladder Cancer Treatment.

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