L-Serine Reduces Reactive Oxygen Species Yield in Cisplatin Treated Zebrafish Utricles

Cisplatin is a chemotherapy compound effective against a variety of cancers. However, it can act as an ototoxin and cause hearing loss by promoting reactive oxygen species (ROS) production in auditory tissues. The antioxidant amino acid, L-serine has been hypothesized to lower levels of cisplatin-mediated ROS. In this project, we investigated whether L-serine can reduce cisplatin-mediated ROS production in auditory tissue and potentially act as an otoprotectant during cisplatin chemotherapy. We used a zebrafish utricular tissue culture system and fluorescent ROS indicator dye to spectrophotometrically measure if L-serine could decrease reactive oxygen species levels in cisplatin-treated tissues. We found that cisplatin treatment increased ROS yield in the utricular tissue while L-serine treatment alone did not alter ROS levels. Interestingly, we also found that equimolar L-serine treatment with cisplatin restored ROS to control levels. These results could be due to L-serine acting as an ROS scavenger. However, it is possible that L-serine could chemically inactivate cisplatin in these tissues. Future experiments are needed to see if L-serine can act as an otoprotectant in auditory tissue without mitigating the effects of cisplatin in cancer cells

RNA-Seq analysis of cisplatin and the monofunctional platinum(II) complex, phenanthriplatin, in A549 non-small cell lung cancer and IMR90 lung fibroblast cell lines

Phenanthriplatin is a new monofunctional platinum(II) complex that binds only one strand of DNA and acts by blocking gene transcription, but its effect on gene regulation has not been characterized relative to the traditional platinum-based complex, cisplatin. A549 non-small cell lung cancer and IMR90 lung fibroblast cells were treated with cisplatin, phenanthriplatin, or a control and then their RNA transcripts were subjected to next generation sequencing analysis. DESeq2 and CuffDiff2 were used to identify up- and downregulated genes and Gene Ontology and Kyoto Encyclopedia of Genes and Genomes databases were used to identify pathways and functions. We found that phenanthriplatin may regulate the genes GPRC5a, TFF1, and TNFRSF10D, which act through p53 to control apoptosis, differently or to a greater extent than cisplatin, and that it, unlike cisplatin, could upregulate ATP5MD, a gene which signals through the Wnt/β catenin pathway. Furthermore, phenanthriplatin caused unique or enhanced effects compared to cisplatin on genes regulating the cytoskeleton, cell migration, and proliferation, e.g., AGAP1, DIAPH2, GDF15, and THSD1 (p < 0.05; q < 0.05). Phenanthriplatin may modulate some oncogenes differently than cisplatin potentially leading to improved clinical outcome, but this monofunctional complex should be carefully matched with cancer gene data to be successfully applied in chemotherapy