Global transcriptional responses to cisplatin in Dictyostelium discoideum identify potential drug targets

Abstract

Dictyostelium discoideum is a useful model for studying mechanisms of cisplatin drug sensitivity. Our previous findings, that mutations in sphingolipid metabolism genes confer cisplatin resistance in D. discoideum and in human cells, raised interest in the resistance mechanisms and their implications for cisplatin chemotherapy. Here we used expression microarrays to monitor physiological changes and to identify pathways that are affected by cisplatin treatment of D. discoideum. We found >400 genes whose regulation was altered by cisplatin treatment of wild-type cells, including groups of genes that participate in cell proliferation and in nucleotide and protein metabolism, showing that the cisplatin response is orderly and multifaceted. Transcriptional profiling of two isogenic cisplatin-resistant mutants, impaired in different sphingolipid metabolism steps, showed that the effect of cisplatin treatment was greater than the effect of the mutations, indicating that cisplatin resistance in the mutants is due to specific abilities to overcome the drug effects rather than to general drug insensitivity. Nevertheless, the mutants exhibited significantly different responses to cisplatin compared with the parent, and >200 genes accounted for that difference. Mutations in five cisplatin response genes (sgkB, csbA, acbA, smlA, and atg8) resulted in altered drug sensitivity, implicating novel pathways in cisplatin response. Our data illustrate how modeling complex cellular responses to drugs in genetically stable and tractable systems can uncover new targets with the potential for improving chemotherapy.drug resistance ͉ sphingolipids ͉ sphingosine kinase ͉ sphingosine-1-phosphate lyase ͉ transcriptional profiling D ictyostelium discoideum is well known for studies of cell and developmental biology and is gaining interest as a model for studying human disease, including cancer (1). A substantial body of work has accumulated using D. discoideum to identify genes and proteins associated with resistance to the anti-cancer drug cisplatin (2).Cisplatin [cis-diamminedichloroplatinum(II)] is used to treat a variety of solid tumors (3), but efficacy is often limited by drug resistance (4). Studies in human tumor cells and cell lines have implicated a number of resistance mechanisms and demonstrated that resistance is multifaceted (5).D. discoideum provides a genetically tractable system to the problem of cisplatin resistance. It is a eukaryote with cellular properties similar to those of human cells (6). Its genome is sequenced, and many genes are homologous to human genes (7). Using insertional mutagenesis screens (8), we isolated mutants with single gene disruptions that have decreased sensitivity to cisplatin (9). One of these strains was null for the sphingosine-1-phosphate (S-1-P) lyase gene sglA, establishing the first link between sphingolipid metabolism and cisplatin sensitivity and defining S-1-P lyase as a potential target for controlling cisplatin sensitivity.S-1-P synthesis is catalyzed by sphingosine kinase from sphin...

The Green Tea Catechin Epigallocatechin Gallate (EGCG) Blocks Cell Motility, Chemotaxis and Development in Dictyostelium discoideum

“…Although Dictyostelium has been used to characterize the activities of bisphosphonates [16], lithium drugs [17], chemotherapies [18] and teratogens [19]–[20], this organism has not been routinely used to characterize the effects of catechins or other natural products. In this study, we investigate the effects of catechins, and especially epigallocatechin gallate (EGCG), on the Dictyostelium life cycle.…”

Dysregulation of Purine Nucleotide Biosynthesis Pathways Modulates Cisplatin Cytotoxicity inSaccharomyces cerevisiae

“…It has been previously shown that depletion of purines in the medium greatly decrease the dATP pool and DNA synthesis in the V79 pur1, a purine auxotrophic mutant of the Chinese hamster lung cell line (Zannis-Hadjopoulos et al, 1980). Others also showed that genes in the nucleotide metabolism, including purB , C / E , D , and H , are greatly induced by cisplatin in Dictyostelium (Van Driessche et al, 2007). Further, treatment with hydroxyurea, an inhibitor of dNTP synthesis and DNA repair (Collins and Oates, 1987), enhances cisplatin cytotoxicity (Albain et al, 1992).…”

Dictyostelium discoideum as a pharmacological model system to study the mechanisms of medicinal drugs and natural products

“…discoideum has also been used in a range of other cancerrelated studies. The role of cisplatin on gene expression in the model has been analysed (Van Driessche et al, 2007), in addition to its regulation of mitogen activated protein kinase phosphatases (Moncho-Amor et al, 2011) and in DNA repair pathways (Gunn et al, 2016). The cellular functions of other anti-cancer treatments, such as bestatin and Poly (ADPribose) polymerase inhibitors have also been analysed in D. discoideum (Kolb et al, 2017, Poloz et al, 2012.…”