RNF8 promotes high linear energy transfer carbon-ion-induced DNA double-stranded break repair in serum-starved human cells

14-3-3σ downregulation sensitizes pancreatic cancer to carbon ions by suppressing the homologous recombination repair pathway

This study explored the role of 14-3-3σ in carbon ion-irradiated pancreatic adenocarcinoma (PAAD) cells and xenografts and clarified the underlying mechanism. The clinical significance of 14-3-3σ in patients with PAAD was explored using publicly available databases. 14-3-3σ was silenced or overexpressed and combined with carbon ions to measure cell proliferation, cell cycle, and DNA damage repair. Immunoblotting and immunofluorescence (IF) assays were used to determine the underlying mechanisms of 14-3-3σ toward carbon ion radioresistance. We used the BALB/c mice to evaluate the biological behavior of 14-3-3σ in combination with carbon ions. Bioinformatic analysis revealed that PAAD expressed higher 14-3-3σ than normal pancreatic tissues; its overexpression was related to invasive clinicopathological features and a worse prognosis. Knockdown or overexpression of 14-3-3σ demonstrated that 14-3-3σ promoted the survival of PAAD cells after carbon ion irradiation. And 14-3-3σ was upregulated in PAAD cells during DNA damage (carbon ion irradiation, DNA damaging agent) and promotes cell recovery. We found that 14-3-3σ resulted in carbon ion radioresistance by promoting RPA2 and RAD51 accumulation in the nucleus in PAAD cells, thereby increasing homologous recombination repair (HRR) efficiency. Blocking the HR pathway consistently reduced 14-3-3σ overexpression-induced carbon ion radioresistance in PAAD cells. The enhanced radiosensitivity of 14-3-3σ depletion on carbon ion irradiation was also demonstrated in vivo. Altogether, 14-3-3σ functions in tumor progression and can be a potential target for developing biomarkers and treatment strategies for PAAD along with incorporating carbon ion irradiation.

A functional reference map of the RNF8 interactome in cancer

Background

RNF8 is an E3 ligase identified as a critical DNA damage-responsive protein. Recently, multiple reports have shown that RNF8 could be used as an important therapeutic target for cancer chemo/radiotherapy. However, the understanding of RNF8 remains limited due to the lack of its interactome reference map and comprehensive analysis of RNF8 in diverse cancers, which underscores the need to map the interactome of RNF8 via high-throughput methods.

Results

A two-way identification method based on LC–MS was designed for the identification of the RNF8 interactome with high-specificity. By in silico analysis and in vitro validation, we identified a new reference map of the RNF8 interactome network containing many new targets, such as YBX1, DNMT1, and HDCA1, new biological functions and the gene-disease associations of RNF8. Our results revealed a close relationship between RNF8 and neurodegenerative diseases or tumor-infiltrating immune cells using bulk RNA-seq and scRNA-seq datasets. As a proof of concept of our interactome map, we validated the direct binding between RNF8 and YBX1 and showed that RNF8 catalyzed the ubiquitination of YBX1. These results demonstrated that RNF8 might be a crucial regulator of YBX1.

Conclusions

Our work provides a unique framework for researchers and clinicians who seek to better explore or understand RNF8-regulated biological functions in cancers. This study will hopefully facilitate the rational design and further development of anti-RNF8 therapy in cancers.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13062-022-00331-z.

Research Progress of Heavy Ion Radiotherapy for Non-Small-Cell Lung Cancer

Non-small-cell lung cancer (NSCLC) has a high incidence and poses a serious threat to human health. However, the treatment outcomes of concurrent chemoradiotherapy for non-small-cell lung cancer are still unsatisfactory, especially for high grade lesions. As a new cancer treatment, heavy ion radiotherapy has shown promising efficacy and safety in the treatment of non-small-cell lung cancer. This article discusses the clinical progress of heavy ion radiotherapy in the treatment of non-small-cell lung cancer mainly from the different cancer stages, the different doses of heavy ion beams, and the patient’s individual factors, and explores the deficiency of heavy ion radiotherapy in the treatment of non-small-cell lung cancer and the directions of future research, in order to provide reference for the wider and better application of heavy ion radiotherapy in the future.