Weighted Epigenetic Site Correlation Network Analysis of Chemotherapy Impacts on Osteosarcoma Cancer Survivors Male Fertility, Sperm, and Endocrine Parameters

The impacts of chemotherapy exposure on adolescent male osteosarcoma survivors as adults was investigated using a number of physiological parameters, with a focus on chemotherapy, reproduction and sperm. The Children’s Oncology Group (COG) clinical sites (protocol ALTE16C1) of previously collected and stored sperm samples were obtained for this analysis. The epigenetic DNA methylation alterations in sperm were assessed in 176 control adult male patients sperm and 183 chemotherapy exposed osteosarcoma survivors’ adult male sperm were provided by COG sites. The current study used a Weighted Gene Co-expression Network Analysis (WGCNA) computational approach that was adopted for use as a Weighted Epigenetic site Correlation Network Analysis (WECNA). This analysis identified correlation coefficients between differential DNA methylation regions (DMRs) and other DNA methylation sites with physiological and chemotherapy parameters. Module-trait relationships of the data were determined for epigenetic modules which highly correlated with sperm parameters, reproductive hormones and several chemotherapies (e.g. cisplatin). Gene associations of these epigenetic sites were identified and correlated to chemotherapy associated genes and pathways, as well as reproductive parameters. Observations demonstrate dramatic impacts of adolescent chemotherapy on later adult life sperm epigenetics. Clearly epigenetics has the potential to mediate the actions of chemotherapy on later life physiology and may potentially impact future generations through epigenetic transgenerational inheritance mechanisms, but this needs further investigation.