Methylation of Tumor Suppressive miRNAs in Plasma from Patients With Pancreaticobiliary Diseases

Epigenetic Regulation of Nuclear Factor Erythroid-2-Related Factor 2 in Colorectal Cancer Cells Resistant to Ionizing Radiation

γ-Radiation resistance is a major obstacle to the success of radiotherapy in colorectal cancer. Antioxidant-related factors contribute to resistance to radiation therapy and, therefore, are targets for improving the therapeutic response. In this study, we evaluated the molecular mechanisms underlying γ-radiation resistance using the colorectal cancer cell line SNUC5 and γ-radiation-resistant variant SNUC5/RR, including analyses of the role of nuclear factor erythroid 2-related factor 2 (NRF2), a transcription factor that regulates antioxidant enzymes, and related epigenetic regulators. Reactive oxygen species (ROS) levels, antioxidant enzyme expression, NRF2 expression, and nuclear translocation were higher in SNUC5/RR cells irradiated with or without 8 Gy than in SNUC5 cells. The DNA demethylase ten-eleven translocation 1 (TET1) expression and TET1 binding to the NRF2 promoter in SNUC5/RR cells were stronger than those in SNUC5 cells, indicating lower methylation of CpG islands in the NRF2 promoter. TET1 knockdown in SNUC5/RR cells suppressed NRF2 expression significantly. Additionally, histone mixed-lineage leukemia (MLL), a histone methyltransferase, was upregulated, leading to increased trimethylation of histone H3 lysine 4, whereas enhancer of zeste homolog 2 (EZH2), a histone methyltransferase, was downregulated, leading to decreased trimethylation of histone H3 lysine 27. Histone deacetylase (HDAC) and histone acetyltransferase (HAT) levels were lower and higher in SNUC5/RR cells than in SNUC5 cells, respectively. MLL and HAT knockdown in SNUC5/RR cells irradiated with or without 8 Gy decreased levels of NRF2 and heme-oxygenase 1, resulting in enhanced γ-radiation sensitivity. These findings support NRF2 as a target for improving the response to radiotherapy in patients with colorectal cancer.

Gaps between needs of patient and public involvement and interests of researchers on pancreatic cancer

OBJECTIVE

Identify whether there were gaps between needs of end-users and interests of researchers focusing on pancreatic cancer.

METHODS

A questionnaire for end-users (patients, close family, others) and researchers was developed to measure value from the perspective of different stakeholder groups. Two separate literature analyses were conducted to assess the prevalence and impact of patient and public involvement (PPI).

RESULTS

Significant gaps were found between end-users and researchers in valuing basic research (15 vs 25 points, p = 0.005) and treatment (36 vs. 26 points, p = 0.015), but not in early diagnosis, risk factors, or quality of life. PPI was absent from the top 100 cited publications on pancreatic cancer research and was featured in 0.1% of all studies within the field.

CONCLUSIONS

Gaps existed between needs of end-users and interests of researchers on basic research and treatment. PPI constituted an insignificant part of the overall pancreatic cancer research literature and had negligible impact in terms of citations.

PRACTICAL IMPLICATIONS

To help close the gaps, PPI should be incorporated throughout the research process. The impact of PPI can be enhanced by prestigious journals in consideration of journal policies and encouragements and by dissemination at academic conferences.