Impact of chemotherapy for breast cancer on leukocyte DNA methylation landscape and cognitive function: a prospective study.

BACKGROUND: Little is known about the effects of chemotherapeutic drugs on DNA methylation status of leukocytes, which may be predictive of treatment benefits and toxicities. Based on a prospective national study, we characterize the changes in leukocyte DNA methylome from pre- to post-chemotherapy (approximately 4 months apart) in 93 patients treated for early stage breast cancer and 48 matched non-cancer controls. We further examined significant methylation changes with perceived cognitive impairment, a clinically significant problem related to cancer and chemotherapy. RESULTS: Approximately 4.2% of the CpG sites measured using the Illumina 450K methylation array underwent significant changes after chemotherapy (p < 1e-7), in comparison to a stable DNA methylome in controls. Post-chemotherapy, the estimated relative proportions of B cells and CD4+ T cells were decreased by a median of 100% and 39%, respectively, whereas the proportion of monocytes was increased by a median of 91%. After controlling for leukocyte composition, 568 CpGs from 460 genes were still significantly altered following chemotherapy. With additional adjustment for chemotherapy regimen, cumulative infusions, growth factors, and steroids, changes in four CpGs remained significant, including cg16936953 in VMP1/MIR21, cg01252023 in CORO1B, cg11859398 in SDK1, and cg19956914 in SUMF2. The most significant CpG, cg16936953, was also associated with cognitive decline in breast cancer patients. CONCLUSIONS: Chemotherapy profoundly alters the composition and DNA methylation landscape of leukocytes in breast cancer patients. Our results shed light on the epigenetic response of circulating immune cell populations to cytotoxic chemotherapeutic drugs and provide possible epigenetic links to the degeneration of cognitive function associated with chemotherapy.

Cognitive Complaints in Survivors of Breast Cancer After Chemotherapy Compared With Age-Matched Controls: An Analysis From a Nationwide, Multicenter, Prospective Longitudinal Study.

Purpose Cancer-related cognitive impairment is an important problem for patients with breast cancer, yet its trajectory is not fully understood. Some previous cancer-related cognitive impairment research is limited by heterogeneous populations, small samples, lack of prechemotherapy and longitudinal assessments, use of normative data, and lack of generalizability. We addressed these limitations in a large prospective, longitudinal, nationwide study. Patients and Methods Patients with breast cancer from community oncology clinics and age-matched noncancer controls completed the Functional Assessment of Cancer Therapy-Cognitive Function (FACT-Cog) at prechemotherapy and postchemotherapy and at a 6-month follow-up as an a priori exploratory aim. Longitudinal models compared FACT-Cog scores between patients and controls at the three assessments and adjusted for age, education, race, menopausal status, and baseline reading ability, anxiety, and depressive symptoms. A minimal clinically important difference cutoff determined percentages of impairment over time. Results Of patients, 581 patients with breast cancer (mean age, 53 years; 48% anthracycline-based regimens) and 364 controls (mean age, 53 years) were assessed. Patients reported significantly greater cognitive difficulties on the FACT-Cog total score and four subscales from prechemotherapy to postchemotherapy compared with controls as well as from prechemotherapy to 6-month follow-up (all P < .001). Increased baseline anxiety, depression, and decreased cognitive reserve were significantly associated with lower FACT-Cog total scores. Treatment regimen, hormone, or radiation therapy was not significantly associated with FACT-Cog total scores in patients from postchemotherapy to 6-month follow-up. Patients were more likely to report a clinically significant decline in self-reported cognitive function than were controls from prechemotherapy to postchemotherapy (45.2% v 10.4%) and from prechemotherapy to 6-month follow-up (36.5% v 13.6%). Conclusion Patients with breast cancer who were treated in community oncology clinics report substantially more cognitive difficulties up to 6 months after treatment with chemotherapy than do age-matched noncancer controls.

Enhanced photocatalytic water oxidation efficiency with Ni(OH)2 catalysts deposited on α-Fe2O3 via ALD.

Atomic layer deposition was used to deposit NiO onto thin-film α-Fe2O3 electrodes for photocatalytic water splitting. Photoelectrochemical conditioning of the deposited NiO converts it to Ni(OH)2, which results in a stable reduction of the photocurrent onset potential for water oxidation by ~300 mV and improves photocurrent density by two-fold at 1.23 V vs. RHE as compared to untreated α-Fe2O3. This enhanced performance is shown to be due to improved charge separation with the ion-permeable Ni(OH)2 catalyst film. These results not only demonstrate one of the most effective water oxidation catalysts when integrated with hematite, but help establish the operational principles that lead to the improved performance.