Biomarkers in radiation oncology

Integrating evolutionarily conserved mechanism of response to radiation for exploring novel Caenorhabditis elegans radiation-responsive genes for estimation of radiation dose associated with spaceflight

During space exploration, space radiation is widely recognized as an inescapable perilous stressor, owing to its capacity to induce genomic DNA damage and escalate the likelihood of detrimental health outcomes. Rapid and reliable estimation of space radiation dose holds paramount significance in accurately assessing the health risks associated with spaceflight. However, the identification of space radiation-responsive genes, with their potential to serve as early indicators for diagnosing radiation dose associated with spaceflight, continues to pose a significant challenge. In this study, based on the evolutionarily conserved mechanism of radiation response, an in silico analysis method of homologous comparison was performed to identify the Caenorhabditis elegans orthologues of human radiation-responsive genes with possible roles in the major processes of response to radiation, and thereby to explore the potential C. elegans radiation-responsive genes for evaluating the levels of space radiation exposure. The results showed that there were 60 known C. elegans radiation-responsive genes and 211 C. elegans orthologues of human radiation-responsive genes implicated in the major processes of response to radiation. Through an investigation of all available transcriptomic datasets obtained from space-flown C. elegans, it was observed that the expression levels of the majority of these putative C. elegans radiation-responsive genes identified in this study were notably changed across various spaceflight conditions. Furthermore, this study indicated that within the identified genes, 19 known C. elegans radiation-responsive genes and 40 newly identified C. elegans orthologues of human radiation-responsive genes exhibited a remarkable positive correlation with the duration of spaceflight. Moreover, a noteworthy presence of substantial multi-collinearity among the majority of these identified genes was observed. This observation lends support to the possibility of treating each identified gene as an independent indicator of radiation dose in space. Ultimately, a subset of 15 potential radiation-responsive genes was identified, presenting the most promising indicators for estimation of radiation dose associated with spaceflight in C. elegans.

Once a clinician, always a clinician: a systematic review to develop a typology of clinician-researcher dual-role experiences in health research with patient-participants

Background

Many health researchers are clinicians. Dual-role experiences are common for clinician-researchers in research involving patient-participants, even if not their own patients. To extend the existing body of literature on why dual-role is experienced, we aimed to develop a typology of common catalysts for dual-role experiences to help clinician-researchers plan and implement methodologically and ethically sound research.

Methods

Systematic searching of Medline, CINAHL, PsycINFO, Embase and Scopus (inception to 28.07.2014) for primary studies or first-person reflexive reports of clinician-researchers’ dual-role experiences, supplemented by reference list checking and Google Scholar scoping searches. Included articles were loaded in NVivo for analysis. The coding was focused on how dual-role was evidenced for the clinician-researchers in research involving patients. Procedures were completed by one researcher (MB) and independently cross-checked by another (JHS). All authors contributed to extensive discussions to resolve all disagreements about initial coding and verify the final themes.

Results

Database searching located 7135 records, resulting in 29 included studies, with the addition of 7 studies through reference checks and scoping searches. Two overarching themes described the most common catalysts for dual-role experiences – ways a research role can involve patterns of behaviour typical of a clinical role, and the developing connection that starts to resemble a clinician-patient relationship. Five subthemes encapsulated the clinical patterns commonly repeated in research settings (clinical queries, perceived agenda, helping hands, uninvited clinical expert, and research or therapy) and five subthemes described concerns about the researcher-participant relationship (clinical assumptions, suspicion and holding back, revelations, over-identification, and manipulation). Clinician-researchers use their clinical skills in health research in ways that set up a relationship resembling that of clinician-patient. Clinicians’ ingrained orientation to patients’ needs can be in tension with their research role, and can set up ethical and methodological challenges.

Conclusion

The typology we developed outlines the common ways dual-role is experienced in research involving clinician-researchers and patient-participants, and perhaps the inevitability of the experience given the primacy accorded to patient well-being. The typology offers clinician-researchers a framework for grappling with the ethical and methodological implications of dual-role throughout the research process, including planning, implementation, monitoring and reporting.

Autocrine human GH promotes radioresistance in mammary and endometrial carcinoma cells

Although recent advances in breast cancer treatment regimes have improved patient prognosis, resistance to breast cancer therapies, such as radiotherapy, is still a major clinical challenge. In the current study, we have investigated the role of autocrine human GH (hGH) in resistance to ionising radiation (IR)-based therapy. Cell viability and total cell number assays demonstrated that autocrine hGH promoted cell regrowth in the mammary carcinoma cell lines, MDA-MB-435S and T47D, and the endometrial carcinoma cell line, RL95-2, following treatment with IR. In addition, autocrine hGH enhanced MDA-MB-435S and T47D cell clonogenic survival following radiation exposure. The enhanced clonogenic survival afforded by autocrine hGH was mediated by JAK2 and Src kinases. Investigation into the DNA repair capacity demonstrated that autocrine hGH reduced IR-induced DNA damage in MDA-MB-435S and T47D cells. Functional antagonism of hGH increased RL95-2 sensitivity to IR in cell viability and total cell number assays, reduced clonogenic survival and enhanced the induction of DNA damage. Thus, autocrine hGH reduced sensitivity to treatment with IR in mammary and endometrial carcinoma cell lines in vitro, while functional antagonism of hGH sensitised endometrial carcinoma cells to IR. Functional antagonism of hGH, used in conjunction with radiotherapy, may therefore enhance treatment efficacy and improve the prognosis of patients with breast and endometrial cancer.