Effect of surgical wound fluids after intraoperative electron radiotherapy on the cancer stem cell phenotype in a panel of human breast cancer cell lines

Biological and clinical review of IORT-induced wound fluid in breast cancer patients

Intraoperative radiotherapy (IORT) has become a growing therapy for early-stage breast cancer (BC). Some studies claim that wound fluid (seroma), a common consequence of surgical excision in the tumor cavity, can reflect the effects of IORT on cancer inhibition. However, further research by our team and other researchers, such as analysis of seroma composition, affected cell lines, and primary tissues in two-dimensional (2D) and three-dimensional (3D) culture systems, clarified that seroma could not address the questions about IORT effectiveness in the surgical site. In this review, we mention the factors involved in tumor recurrence, direct or indirect effects of IORT on BC, and all the studies associated with BC seroma to attain more information about the impact of IORT-induced seroma to make a better decision to remove or remain after surgery and IORT. Finally, we suggest that seroma studies cannot decipher the mechanisms underlying the effectiveness of IORT in BC patients. The question of whether IORT-seroma has a beneficial effect can only be answered in a trial with a clinical endpoint, which is not even ongoing.

Dose-time and Source-dependent Analysis of Intraoperative Radiotherapy-treated Seroma on Breast Cancer Cell Types: A Pilot Study

Background: Intraoperative radiation therapy (IORT) is a novel approach to breast cancer (BC) treatment. Objectives: In this study, we compared the cellular and molecular effects of IORT-treated post-lumpectomy wound fluid (seroma) at the point of IOeRT versus IOxRT on the BC cell line. Methods: Immortalized human BC cell lines: MCF-7, MDA-MB-231, and MCF10 were incubated with seroma from 3 groups of patients (as a pilot study). The first group received Intraoperative electron radiation therapy (IOeRT, Boost dose=12Gy), the second one received IOeRT (Radical dose=21Gy), and the third group was prescribed Intraoperative x-ray radiation therapy (IOxRT, X-ray=20Gy). Cellular and molecular tests were used to investigate how cells are influenced by the IORT-treated seroma. Results: We evaluated the effects of dose-time and source-dependent IORT-treated seroma on BC cell lines. In this study, we observed that IOxRT-treated seroma has the most significant effects on the reduction of proliferation, induced cell cycle arrest, and apoptosis. Furthermore, inhibited migration and invasion of BC cell lines were compared to IOeRT -treated seroma. Conclusions: Although this is a pilot study, we suggest that at 24 h, the IORT (specifically IOxRT)-treated seroma may play an important protective role in the breast tumor bed, which is followed by local recurrence decreases.

Wound fluid sampling methods for proteomic studies: A scoping review

Understanding why some wounds are hard to heal is important for improving care and developing more effective treatments. The method of sample collection used is an integral step in the research process and thus may affect the results obtained. The primary objective of this study was to summarise and map the methods currently used to sample wound fluid for protein profiling and analysis. Eligible studies were those that used a sampling method to collect wound fluid from any human wound for analysis of proteins. A search for eligible studies was performed using MEDLINE, Embase and CINAHL Plus in May 2020. All references were screened for eligibility by one reviewer, followed by discussion and consensus with a second reviewer. Quantitative data were mapped and visualised using appropriate software and summarised via a narrative summary. After screening, 280 studies were included in this review. The most commonly used group of wound fluid collection methods were vacuum, drainage or use of other external devices, with surgical wounds being the most common sample source. Other frequently used collection methods were extraction from absorbent materials, collection beneath an occlusive dressing and direct collection of wound fluid. This scoping review highlights the variety of methods used for wound fluid collection. Many studies had small sample sizes and short sample collection periods; these weaknesses have hampered the discovery and validation of novel biomarkers. Future research should aim to assess the reproducibility and feasibility of sampling and analytical methods for use in larger longitudinal studies.

Transcriptomic and proteomic approaches reveal biological basis of intraoperative radiotherapy-treated tumor bed modification in breast cancer patients: A pilot study

AIM

Intraoperative electron Radiotherapy, herein referred to, as IOeRT is a novel approach in breast cancer (BC) treatment. This study designed to investigate short-term molecular effects of 12Gy as Boost versus 21Gy as Radical dose of IOeRT using high throughput approaches.

MATERIALS AND METHODS

Six BC patients as a pilot study were treated with IOeRT following two separate strategies, including Boost and Radical doses. Approximately 100 mg of tumor bed tissue retrieved from each patient (before IOeRT,immediately, 24 h post-treatment). mRNA sequencing also Isobaric tag for relative and absolute quantitation (iTRAQ) were performed to study the transcriptome and proteome profile of IOeRT-treated tumor bed.

RESULTS

Using NGS, ~6 Giga base (GB) clean data per individual samples were generated. Moreover, by iTRAQ for proteome quantification, in total, 1,045,410 spectrums were generated, likewise 5860 proteins were identified (FDR <0.01).

CONCLUSION

Functional annotation and gene ontology (GO) indicated that significant enrichment in molecular pathways on BC treatment is somehow single high dose-independent. This means that, key molecular pathways in radiotherapy (RT) are equally enriched by both Boost and Radical doses. Generally, by modification of the Radical dose, with the same effectiveness, it is possible to reduce single high dose irradiation in BC.

The Composition of Surgical Wound Fluids from Breast Cancer Patients is Affected by Intraoperative Radiotherapy Treatment and Depends on the Molecular Subtype of Breast Cancer

Invasive oncological procedures affect the remaining tumor cells by increasing their survival, proliferation, and migration through the induction of wound healing response. The phenomena of local relapse after breast-conserving surgery (BCS) has resulted in a series of research and clinical trials with the aim of assessing whether localized intraoperative radiotherapy (IORT), may be beneficial in inhibiting local recurrences. Therefore, it is essential to assess the impact of intraoperative radiotherapy in modulating the immunological response and wound healing process. Thus, we decided to perform a quantitative analysis of the composition of surgical wound fluids (SWF) in two groups of breast cancer (BC) patients: those treated with BCS followed by IORT, and those who underwent BCS alone. We found that several cytokines, which are believed to have anti-tumor properties, were highly expressed in the luminal A breast cancer subtype in the IORT treatment group. Interestingly, we also found significant differences between IORT patients with tumors of different molecular subtypes. Based on these findings, we hypothesized that IORT treatment might be beneficial in changing the tumor bed microenvironment, making it less favorable for tumor recurrence due to decreased concentration of tumor-facilitating cytokines, especially in the luminal A subtype of BC.

Wound fluids collected postoperatively from patients with breast cancer induce epithelial to mesenchymal transition but intraoperative radiotherapy impairs this effect by activating the radiation-induced bystander effect

Wound fluids (WF) are believed to play a role in the local recurrences by inducing an inflammatory process in scar tissue area. Given that most local relapse in primary breast cancer patients occur within the scar tissue area, researchers have investigated whether localized radiotherapy, such as intraoperative radiotherapy (IORT), could be more effective than postoperative RT in inhibiting local tumor recurrence. The epithelial-mesenchymal transition (EMT) program plays a critical role in promoting metastasis in epithelium-derived carcinoma. Given this background the main aim of the present study was to determine the mechanisms by which IORT decreases the tumorigenic potential of WF. We assumed that postoperative fluids from patients would activate the radiation-induced bystander effect (RIBE) in treated cells, thus altering the tumor microenvironment. To confirm this hypothesis, WF collected from patients after breast conserving surgery (BCS) alone, after BCS followed by IORT treatment or WF from BCS patients together with RIBE medium were incubated with MCF7 and MDA-MB-468 cells. Changes in the CSC phenotype, in EMT program and potential to migrate were performed to determine the possible role of WF on the migration of breast cancer cells. Our findings show that wound fluids stimulate the CSC phenotype and EMT program in breast cancer cell lines. This effect was partially abrogated when the cells were incubated in wound fluids collected from patients after breast-conserving surgery followed by IORT. Additionally, we confirmed the role of radiation-induced bystander effect in altering the properties of the WF to induce the CSC phenotype and EMT program.

Surgical wound fluids from patients treated with intraoperative radiotherapy induce radiobiological response in breast cancer cells

Breast cancer is the most common cancer occurring in women. The standard of breast cancer treatment is based on breast-conserving surgery with administration of adjuvant whole breast radiotherapy. Research shows that in-breast relapse is most likely to occur in the tumour bed, i.e. around the scar. Intraoperative radiotherapy (IORT), in which radiation is delivered to the tumour bed, reduces the risk of local recurrence not only through direct cell killing, but also through modification of local microenvironment. Additionally IORT modifies the composition and biological activity of surgical wound fluid. Since many researchers show that radiation damage is mediated through factors secreted to the environment by irradiated cells, we hypothesized that this radiation-induced bystander effect is partly responsible for the change observed in surgical wound fluids. We collected conditioned medium from irradiated breast cancer cells (CM) and surgical wound fluids from patients who underwent IORT (RT-WF) and from patients after breast-conserving surgery alone (WF). We incubated two breast cancer cell lines (MCF-7 and MDA-MB-468) with WF, RT-WF, CM or WF + CM and measured radiobiological response of cells. We measured the level of double-strand breaks, induction of apoptosis and the changes in expression of genes related to DNA damage repair. We observed that stimulation with RT-WF and with WF + CM-induced double-strand breaks and increased expression of DNA damage repair-related genes, which was not observed after stimulation with WF. These results suggest that IOERT induces secretion of bystander factors mediating the genotoxic effect of ionizing radiation.

Intraoperative radiation therapy in uterine cervical cancer: A review

Locally advanced uterine cervical cancer continues to present a high number of pelvic relapses. Intraoperative radiation therapy (IORT) allows a precise therapeutic intensification in the surgical area in cases in which removal of the tumour recurrence is feasible. At the same time, IORT excludes the radiosensitive organs from the field of irradiation. While the first gynecological IORT took place in 1905, procedures have been limited over the years and the series are retrospective, including few patients. At the same, time recurrences are located at different pelvic areas. Both heterogeneity and the long recruiting time make it difficult to correctly interpret the published results. Despite this, we have reviewed the most relevant publications. Some institutions indicated IORT as a boost on the surgical bed of the excised tumor recurrence. In others, IORT permits an extra radiation dose after radical surgery of the primary tumor, usually in stage IIB. Most studies conclude that the addition of IORT increases the local control but probably with little impact on survival. On the other hand, there is a controversy in the indication of IORT in surgically resectable primary tumours. No clear advantage over the usual scheme of chemoradiation and brachytherapy has been detected. Randomized studies that allow a breakthrough in the conclusions are highly unlikely to be performed in this area.

Wound fluids affect miR-21, miR-155 and miR-221 expression in breast cancer cell lines, and this effect is partially abrogated by intraoperative radiation therapy treatment

Breast cancer is the most common malignant disease occurring in women. Conservative breast cancer surgery followed by radiation therapy is currently the standard treatment for this type of cancer. The majority of metastases occur within the scar, which initiated a series of studies. As a result, clinical trials aimed to assess whether localized radiotherapy, as intraoperative radiotherapy (IORT), may more effective in inhibiting the formation of local recurrence compared with the standard postoperative whole breast radiotherapy. The present study determined the role of postoperative wound fluids (WFs) from patients diagnosed with breast cancer subsequent to breast conserving surgery or breast conserving surgery followed by IORT on the expression of three microRNAs (miRNAs), consisting of miR-21, miR-155 and miR-221, in distinct breast cancer cell lines that represent the general subtypes of breast cancer. It was determined that the miRNAs responsible for breast cancer progression, induction of tumorigenesis and enrichment of the cancer stem cell phenotype, which is responsible for resistance to tumor therapy, were highly upregulated in the human epidermal growth factor receptor 2-positive breast cancer SK-BR-3 cell line following stimulation with WFs. It is worth emphasizing, that those changes were more significant in WFs collected from patients after surgery alone. The BT-549 cell line showed altered expression only of miR-155 following incubation with WFs. Notably, this change was not associated with IORT. Additionally, it was indicated that both WFs and RT-WF strongly downregulated the expression of miR-21, miR-155 and miR-221 in basal/epithelial and luminal subtypes of breast cancer. It was concluded that the present study contributes to an increased understanding of the role of surgical WFs and IORT treatment in the regulation of miRNA expression. This may enable the development of the current knowledge of breast cancer biology subsequent to IORT treatment and substantially to improve the therapy in the future.

Intraoperative radiotherapy: Patient selection, management, and follow-up

Intraoperative partial breast radiotherapy is an alternative or an adjunct to fractionated whole breast irradiation for the administration of adjuvant radiotherapy in breast cancer following breast conserving surgery. Establishing intraoperative radiotherapy as a therapeutic modality requires a multidisciplinary approach to patient selection, workup, surgery, radiation protocols, chemotherapy, and patient follow up. In this article, we review the published evidence for best clinical practice, as a guide to the introduction of intraoperative radiotherapy for breast cancer treatment.

Intraoperative Radiotherapy of Breast Cancer and Its Biological Effects

Conservative breast cancer surgery followed by radiation therapy is the standard treatment for this type of cancer. Numerous studies demonstrate that 90% of local recurrences after traditional surgery occur in the same quadrant as the primary cancer. The published data suggest that the wound healing process after surgery alters the area surrounding the original tumor and the modified microenvironment is more favorable for the tumor to recur. The majority of metastases within scar initiated much research, and the consequences of these studies led to clinical trials aimed at assessing whether localized radiotherapy, such as intraoperative radiotherapy (IORT), would be more effective in inhibiting formation of local recurrence than the standard postoperative whole breast radiotherapy. IORT involves irradiation of diseased tissue directly during surgery. The rationale for this approach is the fact that the increase in the radiation dose increases local tumor control, which is the primary goal of radiation therapy. The biological basis of this process are still not thoroughly understood. Gaining new knowledge about the recurrence formation at the molecular level could serve as a starting point for further analysis and to create an opportunity to identify new targets of therapy, and possibly new therapeutic agents.