Abstract B030: Synergistic antitumor effects of cold atmospheric plasma and temozolomide in glioblastoma: multimodal approaches integrating in-vitro, in vivo, and in silico investigations for novel and enhanced therapeutic advancements
Authors: Soni Vikas , Horkowitz Alex , Lin Li , Sherman Jonathan , Keidar Michael 
Published: March 2024

Abstract
Glioblastoma multiforme (GBM) is a common and aggressive brain cancer with a median survival rate of 12 to 18 months after diagnosis. Despite standard treatments, including surgery, radiotherapy, and Temozolomide (TMZ), GBM remains highly resistant to therapy due to its infiltrative pattern of invasion, rapid growth, and propensity to relapse [1]. While overall mortality rates remain high, there is a crucial need for a better understanding of the molecular mechanisms and gene mutations involved in GBM and the development of more effective and adaptive therapeutic approaches. Modulating reactive oxygen species (ROS) levels has been suggested as a therapeutic strategy to selectively target the destruction of cancer cells. To address this, we propose a combination therapy utilizing multi-operational plasma devices, including using cold atmospheric plasma (CAP) jet and plasma discharge tube (PDT) in conjunction with TMZ for GBM treatment. CAP functions by elevating reactive oxygen and nitrogen species (RONS) levels and specifically targeting tumor spread. We investigated various plasma devices and their characteristics using optical emission spectroscopy (OES) and measured the electromagnetic potential and emissions of the PDT. The OES of PDT displayed a similar spectrum as the CAP jet, indicating the presence of ROS. In this study, we performed transcriptomic analysis of glioblastoma cells using high throughput deep RNA-Seq with next-generation sequencing (NGS) to quantify genome-wide gene expression changes. Additionally, we examined signaling pathways and predicted structural changes in consequential proteins caused by gene spectrum up or down-regulation. Our results demonstrate that the combination treatment of CAP and TMZ downregulated vital genes involved in MAPK, P53, DNA repair, and cell cycle pathways. The combination of CAP & TMZ showed a significant antitumor effect, inducing apoptosis and damaging essential proteins in GBM cells. In vitro and microscopic studies verified these results, showing nuclear and cell membrane disruption in cancer cells post-plasma treatment. Our findings demonstrate that the combination of CAP/PDT and TMZ effectively sensitizes GBM cells to TMZ, leading to apoptosis. We have previously shown a non-invasive application of CAP jet on the skull of tumor-bearing mice causing ~78% tumor inhibition [2]. Our current study highlights the potential of PDT for non-invasive treatment in vitro, offering a modality for intracranial delivery in in-vivo models. In conclusion, we propose CAP/PDT and TMZ combination therapy as novel non-invasive treatments for GBM in murine models. This approach offers a promising avenue for addressing the dire need for more effective treatments with minimal impact on normal cells. Further investigations and validation in clinical settings are warranted to significantly improve GBM management and patient outcomes. References: [1] Tan, A. C. et al. Management of glioblastoma: State of the art and future directions. CA: 70, 299–312 (2020) [2] Soni, V.; et al., Cancers, 13, 4485 (2021).
Citation Format: Vikas Soni, Alex Horkowitz, Li Lin, Jonathan Sherman, Michael Keidar. Synergistic antitumor effects of cold atmospheric plasma and temozolomide in glioblastoma: multimodal approaches integrating in-vitro, in vivo, and in silico investigations for novel and enhanced therapeutic advancements [abstract]. In: Proceedings of the AACR Special Conference on Brain Cancer; 2023 Oct 19-22; Minneapolis, Minnesota. Philadelphia (PA): AACR; Cancer Res 2024;84(5 Suppl_1):Abstract nr B030.