Abstract 267: Light-activated molecular nanomachines kill bladder cancer cells
Authors: Nagaraju Supriya , van Venrooy Alexis , Hensley Patrick J. , Bree Kelly K. , Ayala-Orozco Ciceron , Brooks Nathan A. , Izhaky David , Tour James M. , Kamat Ashish M. 
Published: July 2021

Introduction: Molecular nanomachines (MNMs) have been studied for their anti-tumor efficacy in a number of solid malignancies. They consist of small (1 nm) organic molecule-based motors that change conformation upon light activation and mechanically drill holes in the cell membrane resulting in cellular necrosis, representing a novel form of molecular mechanical therapy. Recently, we generated a blue light spectrum (395-405 nm)-activated MNMs which showed promising results in pancreatic cancer cell lines. Herein, we evaluate the in vitro efficacy in urothelial carcinoma, a disease characterized by high rates of recurrence, progression, and therapeutic resistance.

Methods: MNMs activated by the blue light spectrum were synthesized. In vitro efficacy of the activated MNMs (8 µM in 0.1% DMSO) was investigated in TCCSUP and UC-3 human bladder cancer cell lines. Cells were incubated with MNMs for 30 minutes, then treatment groups were subjected to 300 mW/cm2 blue light (comparable to Blue Light Cystoscope) for 4 minutes. Control groups included MNMs without light, 0.1% DMSO (required for solubility of the MNMs) with light, and 0.1% DMSO without light. Cell viability was quantitatively evaluated utilizing propidium iodide and flow cytometry assay with each datapoint representing triplicates. Additionally, cells were grown and subjectively tested for cell adhesion to the culture dish at 1d following light and MNM treatment. In addition, we utilized the wound healing assay to detect changes in cell motility following MNM treatment.

Results: TCCSUP cells exhibited almost 100% loss in viability when treated with light-activated MNMs. Solution only (0.1% DMSO) and unactivated MNMs exhibited less than 5% change in cell viability, whereas, solution and light exhibited 20% reduction in cell viability suggesting some light sensitivity of TCCSUP cells. Cell adhesion assay 1d post-treatment confirmed 100% cell death for the MNMs + light treated cells, while showing survival of cells with light only treatment. In addition, results from wound healing assay conducted on UC-3 cells demonstrated at 72 h, there was significant inhibition of cell motility in the treatment group (MNMs + light) compared to control groups.

Conclusions: Light-activated MNM exhibit in vitro efficacy in multiple human bladder cancer cells lines. MNMs are a promising novel therapeutic modality for the intravesical treatment of bladder cancer, and there are no known resistance mechanisms. Further preclinical characterization of antitumor efficacy and tolerability are necessary in in vivo models.

Citation Format: Supriya Nagaraju, Alexis van Venrooy, Patrick J. Hensley, Kelly K. Bree, Ciceron Ayala-Orozco, Nathan A. Brooks, David Izhaky, James M. Tour, Ashish M. Kamat. Light-activated molecular nanomachines kill bladder cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 267.