Copper transporters and chaperones CTR1, CTR2, ATOX1, and CCS as determinants of cisplatin sensitivity

Abstract

The development of resistance to cisplatin (cDDP) is commonly accompanied by reduced drug uptake or increased efflux. Previous studies in yeast and murine embryonic fibroblasts have reported that the copper (Cu) transporters and chaperones participate in the uptake, efflux, and intracellular distribution of cDDP. However, there is conflicting data from studies in human cells. We used CRISPR-Cas9 genome editing to individually knock out the human copper transporters CTR1 and CTR2 and the copper chaperones ATOX1 and CCS. Isogenic knockout cell lines were generated in both human HEK-293T and ovarian carcinoma OVCAR8 cells. All knockout cell lines had slowed growth compared to parental cells, small changes in basal Cu levels, and varying sensitivities to Cu depending on the gene targeted. However, all of the knockouts demonstrated only modest 2 to 5-fold changes in cDDP sensitivity that did not differ from the range of sensitivities of 10 wild type clones grown from the same parental cell population. We conclude that, under basal conditions, loss of CTR1, CTR2, ATOX1, or CCS does not produce a change in cisplatin sensitivity that exceeds the variance found within the parental population, suggesting that they are not essential to the mechanism by which cDDP enters these cell lines and is transported to the nucleus.

The interactome of the copper transporter ATP7A belongs to a network of neurodevelopmental and neurodegeneration factors

“…Irrespective of the cell genotype, all cells experienced a decrease of MTT metabolization at copper concentrations above 50 µM, likely due to copper toxicity (Figure 8A). These COG- and copper-dependent phenotypes do not reflect general cellular sensitivity to metal-based toxicants as assessed with cisplatin, a cytotoxic agent whose import into HEK293 cells does not require CTR1 copper transporter activity (Figure 8B) (Bompiani et al, 2016). These results demonstrate that COG deficient cells fail to respond to extracellular copper as predicted from the defects in ATP7A and CTR1 surface transport mechanisms.

10.7554/eLife.24722.010Figure 8.COG null cells possess copper metabolism defects.( A ) Wild type, COG1 Δ/Δ , COG8 Δ/Δ and COG1,8 Δ/Δ HEK293 cells were incubated with CuCl 2 ranging from 3–300 μM for 72 hr.

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Cisplatin resistance in cell models: evaluation of metallomic and biological predictive biomarkers to address early therapy failure

“…However, it might be related to their higher Pt influx, as described, 27,37,42,43 even for other platinum chemicals, 44 which could be related to high levels of the copper transport protein CTR1, 23 although recently the influence of this type of protein was considered controversial. 45 Nevertheless, since high Pt influx was not accompanied by high levels of induced DNA adducts, the drug effects on cell viability in these A2780 cells must be related to cisplatin activity in the cell cytoplasm, and not specifically related to apoptosis, because the apoptotic cell number did not significantly change at different Pt concentrations. In this regard, although the lack of induced apoptosis in the A2780 cell line after treatment with cisplatin doses as high as IC 90 had been previously reported, 17 controversial data may be found in the literature.…”

The SGK1 Kinase Inhibitor SI113 Sensitizes Theranostic Effects of the 64CuCl2 in Human Glioblastoma Multiforme Cells

“…Human copper transporter 1 (CTR1), a 190-amino-acid protein of 28 kDa with three transmembrane domains, is the primary protein responsible for importing copper in mammals and is overexpressed in a variety of cancers. This trimeric structure seems to create a central pore functioning as channel [8][9][10]. Several positron-emitting radionuclides with a high atomic number and/ or a long half-life have been proposed both for imaging and therapeutic approach.…”