Up-Regulation of Tiam1 Promotes the Radioresistance of Laryngeal Squamous Cell Carcinoma Through Activation of the JNK/ATF-2 Signaling Pathway

A novel oxidative stress-related gene signature as an indicator of prognosis and immunotherapy responses in HNSCC

PURPOSE

To identify molecular subtypes of oxidative stress-related genes in head and neck squamous cell carcinoma (HNSCC) and to construct a scoring model of oxidative stress-related genes.

METHODS

R language based scRNA-seq and bulk RNA-seq analyses were used to identify molecular isoforms of oxidative stress-related genes in HNSCC. An oxidative stress-related gene scoring (OSRS) model was constructed, which were verified through online data and immunohistochemical staining of clinical samples.

RESULTS

Using TCGA-HNSCC datasets, nine predictive genes for overall patient survival, rarely reported in previous similar studies, were screened. AREG and CES1 were identified as prognostic risk factors. CSTA, FDCSP, JCHAIN, IFFO2, PGLYRP4, SPOCK2 and SPINK6 were identified as prognostic factors. Collectively, all genes formed a prognostic risk signature model for oxidative stress in HNSCC, which were validated in GSE41613, GSE103322 and PRJEB23709 datasets. Immunohistochemical staining of SPINK6 in nasopharyngeal cancer samples validated the gene panel. Subsequent analysis indicated that subgroups of the oxidative stress prognostic signature played important roles during cellular communication, the immune microenvironment, the differential activation of transcription factors, oxidative stress and immunotherapeutic responses.

CONCLUSIONS

The risk model might predict HNSCC prognosis and immunotherapeutic responses.

MAPK11 (p38β) is a major determinant of cellular radiosensitivity by controlling ionizing radiation-associated senescence: An in vitro study

Background and purpose

MAPKs are among the most relevant signalling pathways involved in coordinating cell responses to different stimuli. This group includes p38MAPKs, constituted by 4 different proteins with a high sequence homology: MAPK14 (p38α), MAPK11 (p38β), MAPK12 (p38γ) and MAPK13 (p38δ). Despite their high similarity, each member shows unique expression patterns and even exclusive functions. Thus, analysing protein-specific functions of MAPK members is necessary to unequivocally uncover the roles of this signalling pathway. Here, we investigate the possible role of MAPK11 in the cell response to ionizing radiation (IR).

Materials and methods

We developed MAPK11/14 knockdown through shRNA and CRISPR interference gene perturbation approaches and analysed the downstream effects on cell responses to ionizing radiation in A549, HCT-116 and MCF-7 cancer cell lines. Specifically, we assessed IR toxicity by clonogenic assays; DNA damage response activity by immunocytochemistry; apoptosis and cell cycle by flow cytometry (Annexin V and propidium iodide, respectively); DNA repair by comet assay; and senescence induction by both X-Gal staining and gene expression of senescence-associated genes by RT-qPCR.

Results

Our findings demonstrate a critical role of MAPK11 in the cellular response to IR by controlling the associated senescent phenotype, and without observable effects on DNA damage response, apoptosis, cell cycle or DNA damage repair.

Conclusion

Our results highlight MAPK11 as a novel mediator of the cellular response to ionizing radiation through the control exerted onto IR-associated senescence.

Cell death mechanisms in head and neck cancer cells in response to low and high-LET radiation

Head and neck squamous cell carcinoma (HNSCC) is a common malignancy that develops in or around the throat, larynx, nose, sinuses and mouth, and is mostly treated with a combination of chemo- and radiotherapy (RT). The main goal of RT is to kill enough of the cancer cell population, whilst preserving the surrounding normal and healthy tissue. The mechanisms by which conventional photon RT achieves this have been extensively studied over several decades, but little is known about the cell death pathways that are activated in response to RT of increasing linear energy transfer (LET), including proton beam therapy and heavy ions. Here, we provide an up-to-date review on the observed radiobiological effects of low- versus high-LET RT in HNSCC cell models, particularly in the context of specific cell death mechanisms, including apoptosis, necrosis, autophagy, senescence and mitotic death. We also detail some of the current therapeutic strategies targeting cell death pathways that have been investigated to enhance the radiosensitivity of HNSCC cells in response to RT, including those that may present with clinical opportunities for eventual patient benefit.