Epigenetic Regulation of Claudin-1 in the Development of Ovarian Cancer Recurrence and Drug Resistance

Over 21,000 women are diagnosed with ovarian cancer (OC) in the United States each year and over half that number succumb to this disease annually, often due to recurrent disease. A deeper understanding of the molecular events associated with recurrent disease is needed to identify potential targets. Using genome-scale DNA methylation and gene expression data for 16 matched primary-recurrent advanced stage serous epithelial OCs, we discovered that Claudin-1 (CLDN1), a tight junction protein, shows a stronger correlation between expression and methylation in recurrent versus primary OC at multiple CpG sites (R= –0.47 to −0.64 versus R= -0.32 to −0.57, respectively). An independent dataset showed that this correlation is stronger in tumors from short-term (<3y) survivors than in tumors from long-term (>7y) survivors (R= −0.41 to −0.46 versus R= 0.06 to −0.19, respectively). The presence of this inverse correlation in short-term survivors and recurrent tumors suggests an important role for this relationship and potential predictive value for disease prognosis. CLDN1 expression increased following pharmacologic inhibition of DNA methyltransferase activity (p< 0.001), thus validating the role of methylation in CLDN1 gene inhibition. CLDN1 knockdown enhanced chemosensitivity and suppressed cell proliferation, migration, and wound healing (p< 0.05). Stable CLDN1 knockdown in vivo resulted in reduced xenograft tumor growth but did not reach significance. Our results indicate that the relationship between CLDN1 methylation and expression plays an important role in OC aggressiveness and recurrence.

Cannabinoid exposure and altered DNA methylation in rat and human sperm

Little is known about the reproductive effects of paternal cannabis exposure. We evaluated associations between cannabis or tetrahydrocannabinol (THC) exposure and altered DNA methylation in sperm from humans and rats, respectively. DNA methylation, measured by reduced representation bisulfite sequencing, differed in the sperm of human users from non-users by at least 10% at 3,979 CpG sites. Pathway analyses indicated Hippo Signaling and Pathways in Cancer as enriched with altered genes (Bonferroni p < 0.02). These same two pathways were also enriched with genes having altered methylation in sperm from THC-exposed versus vehicle-exposed rats (p < 0.01). Data validity is supported by significant correlations between THC exposure levels in humans and methylation for 177 genes, and substantial overlap in THC target genes in rat sperm (this study) and genes previously reported as having altered methylation in the brain of rat offspring born to parents both exposed to THC during adolescence. In humans, cannabis use was also associated with significantly lower sperm concentration. Findings point to possible pre-conception paternal reproductive risks associated with cannabis use.

Safety and feasibility of a self-monitored, home-based phase II exercise program for high risk patients after cardiac surgery

OBJECTIVE

To determine the safety and effectiveness of a self-monitored, home-based phase II exercise program for high risk patients after cardiac surgery.

METHODS

High risk patients were defined as those presenting with severe left ventricular dysfunction with an ejection fraction less than 35%, severe ventricular arrhythmias, incomplete revascularization, abnormal response to a standard walking test or significant (grade 3/4) valvular regurgitation persisting postoperatively. Eighty patients (mean age 58.5 +/- 8.9 years) were randomly assigned to two groups. The experimental group (n = 37) received a home program of aerobic training with an intensity gradually increasing from 1.5 to 4.0 multiples of resting oxygen consumption (METs). This program was started at discharge from the hospital and lasted eight weeks. The control group (n = 43) received general guidelines for progressive increase of their activity level. Functional capacity was measured at discharge by the 6 min walking test and between the sixth and eighth week following discharge by a symptom-limited exercise test, according to the Naughton protocol.

RESULTS

No cardiovascular complications occurred during the training program. At the final evaluation, there was no significant difference between the experimental and control groups regarding aerobic capacity (5.1 +/- 1.8 versus 4.9 +/- 1.6 METs respectively, P = 0.61), nor peak rate-pressure product (22.8 +/- 4.9 versus 23.6 +/- 5.2 beats/min x mmHg x 10(3) respectively, P = 0.54).