Using the qPCR we had calculated the ratio between the expression of the gene ATP7A, which encodes the copper transporter ATP7A, and the reference gene ACTB in ovarian clinical samples, which were obtained during diagnostic laparoscopy from 16 patients with ovarian cancer. In the blood plasma and ascites of the same patients, we measured ceruloplasmin concentrations using an ELISA test and later investigated the association between the ratio of ATP7A/ACTB expression and ceruloplasmin concentrations in both fluids, since both ATP7A and ceruloplasmin are involved in the development of chemoresistance to platinum-based cytotoxic drugs (Pt-BM) in ovarian cancer. We demonstrated a statistically significant association between the ratio of ATP7A/ACTB expression and ceruloplasmin concentrations in preoperative blood plasma of patients with all histological subtypes who had shown no signs of ovarian necrosis (r = 0.591) and an even stronger association in patients with high grade serous carcinoma (HGSC) who had shown no signs of ovarian necrosis (r = 0.7639). We also demonstrated that patients with all histological subtypes who had shown no signs of ovarian necrosis had statistically significantly (p-value < 0.1) higher ceruloplasmin concentrations in preoperative plasma if the ratio of ATP7A/ACTB expression was > 1. The ratio of ATP7A/ACTB expression was not associated with ceruloplasmin concentration in ascites. Using intracellular staining coupled with flow cytometry of the ATP7A transporter in HOSEpiC, OAW28, and HT1080 cell lines, we were able to demonstrate statistically significantly (p-value < 0.05) higher levels of ATP7A in OAW28 cells, which were isolated from a patient with chemoresistant ovarian cancer, compared to cells of the healthy ovarian cell line HOSEpiC and the fibrosarcoma cell line HT1080, which served as a control for primary antibody binding with ATP7A.
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