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Endocrine Abstracts (2020) 70 AEP530 | DOI: 10.1530/endoabs.70.AEP530

Cancer exosomes emerged as important mediators of cancer drug resistance. Drug exposure-mediated EveR in HCC cell lines can be reversed by VitD pre- and co-treatment. The current study aimed to investigate whether cancer exosomes from EveR HCC cell line are able to induce EveR in parental cells and whether VitD may activate reversal effect on exosome-mediated EveR.

To this purpose, parental JHH-6 and EveR JHH-6 cell line were used. The uptakeof exosomes, staining with membrane dye PKH67, has been evaluated using immunofluorescence (IF). Recipient parental JHH-6 cells were treated for 16 days with exosomes from EveR cells (Exo EveR parental JHH-6) and cell proliferation was evaluated by DNA assay in parental, EveR and Exo EveR parental JHH-6 cells after treatment with everolimus (EVE) at escalating doses (from 10–11 M to 10–7 M) for 6 days, with and without VitD 10–7 M at lowest EVE concentrations used to better visualized the drug effect. Intracellular c-MYC and YAP-1 protein regulation was investigated by western blot (WB) after 6 days of VitD treatment in parental JHH-6, EveR JHH-6 and Exo EveR Parental JHH-6. JHH-6 parental cells were able to uptake exosomes from EveR JHH-6 cells within 18 hrs as shown by IF. Exosome’s uptake conferred EveR to parental JHH-6 cells. This effect was visible in particular at lowest EVE concentrations. Treatment with EVE 10–10 M induced 19.76% of inhibition (P = 0.05 vs control) in parental JHH-6 but no significant inhibition in EveR JHH-6 and Exo EveR parental JHH-6; EVE 10–9 M induced 56.53% (P = 0.0001 vs control) in parental JHH-6, 26.11% of inhibition (P = 0.05 vs control; p = 0.05 vs EVE 10–9 M in parental JHH-6) in Exo EveR parental JHH-6 but not in EveR JHH-6. VitD alone induced 50.19% of inhibition (P = 0.0001 vs control) in parental JHH-6 but no significant inhibition in EveR JHH-6 and Exo EveR parental JHH-6, while co-treatment of VitD with EVE 10–11 M and 10–10 M induced 54.78%, 56.09% and 29.61% of inhibition (P = 0.0001 and P = 0.01 vs EVE 10–11 M alone) and 28.06%, 25.37% and 38.60% of inhibition (P = 0.01, P = 0.05 and P = 0.0001 vs EVE 10–10 M alone)in parental, EveR and Exo EveR parental JHH-6, respectively. Moreover, EveR and Exo EveR parental JHH-6 showed c-Myc and YAP-1 protein upregulation compared to parental JHH-6 but 6 days VitD treatment downregulated their expression. In conclusion, these preliminary data demonstrated that VitD may regulate exosome-mediated drug-resistance mechanisms in JHH-6 cell line, although these mechanisms need to be confirmed in other HCC cell lines.

Volume 70

22nd European Congress of Endocrinology

05 Sep 2020 - 09 Sep 2020

European Society of Endocrinology 

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