Environmental epigenetics describes how environmental factors affect cellular epigenetics and, hence, human health. Epigenetic marks alter the spatial conformation of chromatin to regulate gene expression. Environmental factors with epigenetic effects include behaviors, nutrition, and chemicals and industrial pollutants. Epigenetic mechanisms are also implicated during development in utero and at the cellular level, so environmental exposures may harm the fetus by impairing the epigenome of the developing organism to modify disease risk later in life. By contrast, bioactive food components may trigger protective epigenetic modifications throughout life, with early life nutrition being particularly important. Beyond their genetics, the overall health status of an individual may be regarded as an integration of many environmental signals starting at gestation and acting through epigenetic modifications. This review explores how the environment affects the epigenome in health and disease, with a particular focus on cancer. Understanding the molecular effects of behavior, nutrients, and pollutants might be relevant for developing preventative strategies and personalized heath programs. Furthermore, by restoring cellular differentiation, epigenetic drugs could represent a potential strategy for the treatment of many diseases including cancer.

Background: BRAF mutations occurring in 1%e5% of patients with non-small-cell lung cancer (NSCLC) are therapeutic targets for these cancers but the impact of the exact mutation on clinical activity is unclear. The French National Cancer Institute (INCA) launched the AcSé vemurafenib trial to assess the efficacy and safety of vemurafenib in cancers with various BRAF mutations. We herein report the results of the NSCLC cohort. Patients and methods: Tumour samples were screened for BRAF mutations in INCA-certified molecular genetic centres. Patients with BRAF-mutated tumours progressing after 1 line of treatment were proposed vemurafenib 960 mg twice daily. Between October 2014 and July 2018, 118 patients were enrolled in the NSCLC cohort. The primary outcome was the objective response rate (ORR) assessed every 8 weeks (RECIST v1.1). A sequential Bayesian approach was planned with an inefficacy bound of 10% for ORR. If no early stopping occurred, the treatment was of interest if the estimated ORR was 30% with a 90% probability. Secondary outcomes were tolerance, response duration, progression-free survival (PFS), and overall survival (OS). Results: Of the 118 patients enrolled, 101 presented with a BRAF V600 mutation and 17 with BRAF nonV600 mutations; the median follow-up was 23.9 months. In the BRAF nonV600 cohort, no objective response was observed and this cohort was stopped. In the BRAF V600 cohort, 43/96 patients had objective responses. The mean Bayesian estimated success rate was 44.9% [95% confidence intervals (CI) 35.2%e54.8%]. The ORR had a 99.9% probability of being 30%. Median response duration was 6.4 months, median PFS was 5.2 months (95% CI 3.8e6.8), and OS was 10 months (95% CI 6.8e15.7). The vemurafenib safety profile was consistent with previous publications. Conclusion:Routine biomarker screening of NSCLC should include BRAF V600 mutations. Vemurafenib monotherapy is effective for treating patients with BRAF V600 -mutated NSCLC but not those with BRAF nonV600 mutations. Trial registration: ClinicalTrials.gov identifier: NCT02304809.

ZD1839 ('Iressa'), an orally active, selective epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, is currently being investigated in clinical trials as a treatment for cancer. 'Iressa' is a trademark of the AstraZeneca group of companies. We have previously demonstrated a synergistic interaction between ZD1839 and cisplatin/5-fluorouracil (5FU) in CAL33, a human head and neck cancer cell line that markedly expresses EGFR. This study examined the effects of this drug combination on the cell cycle, cell cycle regulators, apoptosis-related factors, EGFR-related signalling and DNA repair in CAL33 cells. The cells were incubated with ZD1839 alone for 48 h, then cisplatin and 5FU were added. Exposure to the drug combination continued for a further 48 h. ZD1839 alone induced accumulation of cells in the G0/G1 phase of the cell cycle at 24 h accompanied by a concomitant increase in p21, p27 and Bax, a significant decrease in Bcl2 and a decrease in Akt phosphorylation. A decrease in DNA-PK was observed at 48 h. ZD1839 alone had no effect on caspase-3 activity, but addition of ZD1839 to cisplatin-5FU led to a significant increase in caspase-3 activity at 96 h. Thus, ZD1839 affects key cellular pathways controlling cell proliferation, apoptosis and DNA repair. These data provide a rationale to support clinical trials combining ZD1839 and cisplatin -5FU and other protocols that combine EGFR-targeting agents with chemotherapy or radiotherapy.

N-myc downstream-regulated gene-1 (NDRG1) is a recently described hypoxia-inducible protein that is upregulated in various human cancers. Pancreatic ductal adenocarcinoma, called pancreatic cancer, is a highly aggressive cancer that is characterised by its avascular structure, which results in a severe hypoxic environment. In this study, we investigated whether NDRG1 is upregulated in these tumours, thus providing a novel marker for malignant cells in the pancreas. By immunohistochemistry, we observed that NDRG1 was highly expressed in well-differentiated cells of pancreatic cancer, whereas the poorly differentiated tumour cells were negative. In addition, hyperplastic islets and ducts of nonquiescent pancreatic tissue were positive. To further explore its selective expression in tumours, two well-established pancreatic cancer cell lines of unequal differentiation status were exposed to 2% oxygen. NDRG1 mRNA and protein were upregulated by hypoxia in the moderately differentiated Capan-1 cells; however, its levels remained unchanged in the poorly differentiated Panc-1 cell line. Taken together, our data suggest that NDRG1 will not serve as a reliable marker of tumour cells in the pancreas, but may serve as a marker of differentiation. Furthermore, we present the novel finding that cellular differentiation may be an important factor that determines the hypoxia-induced regulation of NDRG1.

NDRG1 is a hypoxia-inducible protein, whose modulated expression is associated with the progression of human cancers. Here, we reveal that NDRG1 is markedly upregulated in the cytoplasm and on the membrane in human hepatocellular carcinoma (HCC). We demonstrate further that hypoxic stress increases the cytoplasmic expression of NDRG1 in vitro, but does not result in its localization on the plasma membrane. However, grown within an HCC-xenograft in vivo, cells express NDRG1 in the cytoplasm and on the plasma membrane. In conclusion, hypoxia is a potent inducer of NDRG1 in HCCs, albeit requiring additional stimuli within the tumour microenvironment for its recruitment to the membrane.