Surgical Wound Fluids from Patients with Breast Cancer Reveal Similarities in the Biological Response Induced by Intraoperative Radiation Therapy and the Radiation-Induced Bystander Effect-Transcriptomic Approach.

Kulcenty Kulcenty,Kulcenty Kulcenty,Rucinski Rucinski,Murawa Murawa,Murawa Murawa,Piotrowski Piotrowski,Piotrowski Piotrowski,Jopek Jopek,Wroblewska Wroblewska,Suchorska Suchorska,Suchorska Suchorska

doi:10.3390/ijms21031159

Abstract

In patients with breast cancer who undergo breast-conserving surgery (BCS), more than 90% of local recurrences occur in the same quadrant as the primary cancer. Surgical wound fluids (SWF) are believed to play a role in this process by inducing an inflammatory process in the scar tissue area. Despite strong clinical data demonstrating the benefits of intraoperative radiotherapy (IORT), the biological basis underlying this process remains poorly understood. Ionizing radiation (IR) directly affects cells by damaging DNA, thereby altering the cell phenotype. IR directly affects cancer cells and also influences unirradiated cells located nearby, a phenomenon known as the radiation-induced bystander effect (RIBE), significantly modifying the tumor microenvironment. We hypothesized that SWF obtained from patients after BCS and IORT would induce a radiobiological response (due to RIBE) in unirradiated cells, thereby modifying their phenotype. To confirm this hypothesis, breast cancer cells were incubated with SWF collected from patients after BCS: (1) without IORT (wound fluid (WF) group), (2) with IORT (radiotherapy wound fluid (RT-WF) group), and (3) WF with conditioned medium from irradiated cells (WF+RIBE group) and then subjected to microarray analysis. We performed gene set enrichment analysis to determine the biological processes present in these cells. This analysis showed that the RT-WF and WF+RIBE groups shared common biological processes, including the enhancement of processes involved in cell-cycle regulation, DNA repair, and oxidative phosphorylation. The WF group was characterized by overrepresentation of pathways involved in the INF-α and INF-γ response, inflammatory response, and the IL6 JAK/STAT3 signaling pathway. These findings show that MDA-MB-468 cells stimulated with surgical wound fluids obtained from patients who underwent BCS plus IORT and from cells stimulated with SWF plus RIBE share common biological processes. This confirms the role of the radiation-induced bystander effect in altering the biological properties of wound fluids.

Highlights

In patients with breast cancer treated with breast-conserving surgery (BCS), metastases and recurrences are the leading cause of cancer-related mortality [1]
While the wound fluid (WF) group was highly segregated from the radiotherapy wound fluid (RT-WF) and WF-radiation-induced bystander effect (RIBE) groups, the RT-WF and WF-RIBE cells were very similar to each other (Supplementary Figure S1)
We showed that (1) surgical wound fluids collected from breast cancer patients activate numerous biological pathways considered to be hallmarks of cancer in the MDA-MB-468 cell line, (2) both Intraoperative radiation therapy (IORT) and RIBE alter the properties of surgical wound fluids, and both of these activate the same pathways in the MDA-MB-468 cell line, (3) the biological pathways activated by RT-WF and WF+RIBE mediums in MDA-MB-468 cells indicate that these cells have lower tumorigenic potential than cells stimulated with SWF obtained from patients treated with BCS alone

Summary

Introduction

In patients with breast cancer treated with breast-conserving surgery (BCS), metastases and recurrences are the leading cause of cancer-related mortality [1]. Studies using global transcriptome analysis of a panel of triple-negative breast cancer (TNBC) cell lines have found that stimulation with surgical wound fluid (SWF) significantly increases the expression of genes related to wound response, cytokine activity, and locomotory characteristics [10]. Belletti et al [6] showed that IORT after BCS alters this effect, making the microenvironment less favorable for tumor cells. Those authors found that SWF from patients after BCS stimulates the proliferation, invasion, and migration of breast cancer cells, but administration of IORT abrogates this effect. The biological basis underlying this process is still not well-understood

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