Napabucasin overcomes cisplatin resistance in ovarian germ cell tumor-derived cell line by inhibiting cancer stemness

Abstract

Background: Cisplatin resistance of ovarian yolk sac tumors (oYST) is a clinical challenge due to dismal patient prognosis, even though the disease is extremely rare. We investigated potential association between cisplatin resistance and cancer stem cell (CSC) markers in chemoresistant oYST cells and targeting strategies to overcome resistance in oYST. Methods: Chemoresistant cells were derived from chemosensitive human oYST cells by cultivation in cisplatin in vitro. Derivative cells were characterized by chemoresistance, functional assays, flow cytometry, gene expression and protein arrays focused on CSC markers. RNAseq, methylation and microRNA profiling were performed. Quail chorioallantoic membranes (CAM) with implanted oYST cells were used to analyze the micro-tumor extent and interconnection with the CAM. Tumorigenicity in vivo was determined on immunodeficient mouse model. Chemoresistant cells were treated by inhibitors intefering with the CSC properties to examine the chemosensitization to cisplatin. Results: Long-term cisplatin exposure resulted in seven-fold higher IC 50 value in resistant cells, cross-resistance to oxaliplatin and carboplatin, and increased migratory capacity, invasiveness and tumorigenicity, associated with hypomethylation of differentially methylated genes/promotors. Resistant cells exhibited increased expression of prominin-1 (CD133), ATP binding cassette subfamily G member 2 (ABCG2), aldehyde dehydrogenase 3 isoform A1 (ALDH3A1), correlating with reduced gene and promoter methylation, as well as increased expression of ALDH1A3 and higher overall ALDH enzymatic activity, rendering them cross-resistant to DEAB, disulfiram and napabucasin. Salinomycin and tunicamycin were significantly more toxic to resistant cells. Pretreatment with napabucasin resensitized the cells to cisplatin and reduced their tumorigenicity in vivo. Conclusions: The novel chemoresistant cells represent unique model of refractory oYST. CSC markers are associated with cisplatin resistance being possible targets in chemorefractory oYST.

Differential gene expression in cisplatin-resistant and -sensitive testicular germ cell tumor cell lines

“…Of course, we are aware of the fact that our study has some limitations. These result mainly from the combination of cell lines used, as only one pair of TGCT cell lines originates from the same cell clone and resistant derivative was not really made CDDPresistant, for instance by cultivation with sub-lethal doses of this drug, as used in recent works in the field [96][97][98]. Instead, the parental CDDP-sensitive cell line was in vitro differentiated using differentiation-inducing medium.…”

Are Changes in the Percentage of Specific Leukocyte Subpopulations Associated with Endogenous DNA Damage Levels in Testicular Cancer Patients?

“…Their resistance to CDDP (expressed as the IC 50 value) was preserved. The IC 50 value for CDDP increased from 0.45 µg/mL in TCam-2 cells to 1.38 µg/mL in TCam-2 CisR cells, from 0.35 µg/mL in NOY-1 cells to 2.37 µg/mL in NOY-1 CisR cells and from 0.01 µg/mL in NTERA-2 cells to 0.31 µg/mL in NTERA-2 CisR cells [42,43].…”

Targeting of Deregulated Wnt/β-Catenin Signaling by PRI-724 and LGK974 Inhibitors in Germ Cell Tumor Cell Lines

“…Cisplatin-resistant variants of parental cell lines, designated as CisR, were all derived by propagating the cells in increasing concentrations of cisplatin (Hospira UK Ltd., Warwickshire, UK) for 6 months as described previously [ 35 , 86 ]. Briefly, exponentially growing cells were exposed to 0.05 µg/mL cisplatin initially.…”