Normal tissue tolerance amongst paediatric brain tumour patients- current evidence in proton radiotherapy

Proteomics and lipidomics of human umbilical cord mesenchymal stem cells exposed to ionizing radiation

OBJECTIVES

Mesenchymal stem cell (MSC)-based therapies exhibit beneficial effects on various forms of tissue damage, including ionizing radiation-induced lesions. However, whether ionizing radiation affects the functions of human umbilical cord mesenchymal stem cells (hucMSCs) remains unclear. This study aimed to investigate the effect and possible mechanisms of ionizing radiation on the proliferation and differentiation of hucMSCs.

METHODS

The hucMSCs were divided into the 1 Gy group (exposure to a single dose (1 Gy) of X-ray radiation (1 Gy/min) for 14 days) and control (without radiation treatment) group. The proliferation, apoptosis, and adipogenic and osteogenic differentiation abilities of hucMSCs in the two groups were evaluated. Moreover, the lipidomics and proteomics analyses were conducted to explore crucial lipids and proteins by which ionizing radiation affected the functions of hucMSCs. In addition, the effects of BYSL on radiation-treated hucMSCs were explore, as well as the involved potential mechanisms.

RESULTS

X-ray radiation treatment inhibited proliferation, promoted apoptosis, and decreased adipogenic and osteogenic differentiation abilities of hucMSCs. Key lipids, such as triglyceride (TG) and phosphatidylcholine (PC), and hub proteins (BYSL, MRTO4, and RRP9) exhibited significant differences between the 1 Gy group and control group. Moreover, BYSL, MRTO4, and RRP9 were significantly correlated with TG and PC. BYSL overexpression evidently promoted the cell proliferation, adipogenic and osteogenic differentiation abilities of radiation-treated hucMSCs, as well as the protein expression levels of p-GSK-3β/GSK-3β and β-catenin, while suppressed cell apoptosis. However, the GSK-3β inhibitor (1-Az) treatment reversed the protein expression levels of p-GSK-3β/GSK-3β, β-catenin and BYSL, as well as the cell proliferation, apoptosis, adipogenic and osteogenic differentiation abilities of radiation-treated hucMSCs.

CONCLUSIONS

Our findings reveal that the proliferation and differentiation of hucMSCs are suppressed by radiation, which may be associated with the changes of key lipids (TG and PC) and proteins (BYSL, MRTO4, and RRP9). Furthermore, BYSL promotes adipogenic and osteogenic differentiation abilities of radiation-treated hucMSCs via GSK-3β/β-catenin pathway. These findings help explain the response of hucMSCs to radiation and have clinical implications for improving the outcomes of MSC-based therapies after radiotherapy.

Modelling the influence of radiosensitivity on development of second primary cancer in out-of-field organs following proton therapy for paediatric cranial cancer

OBJECTIVE

Radiobiological modelling the risks of second primary cancer (SPC) after proton therapy (PT) for childhood cranial cancer remains largely unknown. Organ-specific dose-response risk factors such as radiosensitivity require exploration. This study compared the influence of radiosensitivity data (slope of βEAR) on children's lifetime attributable risks (LAR) of SPC development in out-of-field organs following cranial scattering and scanning PT.

METHODS

Out-of-field radiosensitivity parameter estimates for organs (α/β and βEAR) were sourced from literature. Physical distances for 13 out-of-field organs were measured and input into Schneider's SPC model. Sensitivity analyses were performed as a function of radiosensitivity (α/β of 1-10 Gy) and initial slope (βEAR) from Japanese/UK data to estimate the influence on the risk of radiation-induced SPC following scattering and scanning PT.

RESULTS

Models showed similar LAR of SPC estimates for age and sex-matched paediatric phantoms, however, for breast there was a significant increase using Japanese βEAR data. For most organs, scattering PT demonstrated a larger risk of LAR for SPC which increased with α/β.

CONCLUSION

Breast tissue exhibited the highest susceptibility in calculated LAR risk, demonstrating the importance for accurate data input when estimating LAR of SPC.

ADVANCES IN KNOWLEDGE

The findings of this study demonstrated younger female patients undergoing cranial proton therapy have a higher risk of developing second primary cancer of the breast tissue. Long-term multicenter registries are important to improve predictive radiobiological modelling studies of side effects.

Can We Compare the Health-Related Quality of Life of Childhood Cancer Survivors Following Photon and Proton Radiation Therapy? A Systematic Review

Simple Summary

Proton radiation therapy is a radiation oncology innovation expected to produce superior health-related quality of life (HRQoL) outcomes for children with cancer, compared to conventional photon radiation therapy. The review aim is to identify if clinical evidence exists to support the anticipated HRQoL improvements for children receiving proton radiation therapy. HRQoL outcomes of 1986 childhood cancer survivors are described. There is insufficient quality evidence to compare HRQoL outcomes between proton and photon radiation therapy. Therefore, the current state of the literature does not conclude that proton radiation therapy produces superior HRQoL outcomes for childhood cancer survivors. Despite recommendations, no evidence of routine HRQoL assessment using patient-reported outcomes in paediatric radiation oncology are identified. Further rigorous collection and reporting of HRQoL data is essential to improve patient outcomes, and to adequately compare HRQoL between radiation therapy modalities.

Abstract

Paediatric cancer patients have a risk of late side effects after curative treatment. Proton radiation therapy (PRT) has the potential to reduce the incidence and severity of toxicities produced by conventional photon radiation therapy (XRT), which may improve the health-related quality of life (HRQoL) in children. This systematic review aimed to identify the evidence of HRQoL outcomes in childhood cancer survivors following XRT and PRT. Medline, Embase, and Scopus were systematically searched. Thirty studies were analysed, which described outcomes of 1986 childhood cancer survivors. Most studies (n = 24) described outcomes for children with a central nervous system (CNS) tumour, four studies reported outcomes for children with a non-CNS tumour, and two studies combined CNS and non-CNS diagnoses within a single cohort. No studies analysed routine HRQoL collection during paediatric radiation oncology clinical practice. There is insufficient quality evidence to compare HRQoL outcomes between XRT and PRT. Therefore, the current state of the literature does not conclude that PRT produces superior HRQoL outcomes for childhood cancer survivors. Standardised clinical implementation of HRQoL assessment using patient-reported outcomes is recommended to contribute to improvements in clinical care whilst assisting the progression of knowledge comparing XRT and PRT.