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A ferrocene-containing nucleoside analogue targets DNA replication in pancreatic cancer cells.

ABSTRACT: Pancreatic ductal adenocarcinoma (PDAC) is a disease that remains refractory to existing treatments including the nucleoside analogue gemcitabine. In the current study we demonstrate that an organometallic nucleoside analogue, the ferronucleoside 1-(S,Rp), is cytotoxic in a panel of PDAC cell lines including gemcitabine-resistant MIAPaCa2, with IC50 values comparable to cisplatin. Biochemical studies show that the mechanism of action is inhibition of DNA replication, S-phase cell cycle arrest and stalling of DNA-replication forks, which were directly observed at single molecule resolution by DNA-fibre fluorography. In agreement with this, transcriptional changes following treatment with 1-(S,Rp) include activation of three of the four genes (HUS1, RAD1, RAD17) of the 9-1-1 check point complex clamp and two of the three genes (MRE11, NBN) that form the MRN complex as well as activation of multiple downstream targets. Furthermore, there was evidence of phosphorylation of checkpoint kinases 1 and 2 as well as RPA1 and gamma H2AX, all of which are considered biochemical markers of replication stress. Studies in p53-deficient cell lines showed activation of CDKN1A (p21) and GADD45A by 1-(S,Rp) was at least partially independent of p53. In conclusion, because of its potency and activity in gemcitabine-resistant cells, 1-(S,Rp) is a promising candidate molecule for development of new treatments for PDAC.

SUBMITTER: Rana M

PROVIDER: S-EPMC9320222 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:To determine the relationship between host immunity and the characteristics of viral infection or nucleoside analogues (NAs) themselves in patients with chronic hepatitis B (CHB) receiving NA therapy.Fifty-two hepatitis B envelope antigen (HBeAg) positive CHB patients were enrolled and divided equally into two groups. One group received telbivudine (LDT, 600 mg/d), and the other group received lamivudine (LAM, 100 mg/d). Clinical, virological and immunological parameters were assessed at the baseline and at 4, 12, 24, 36 and 48 wk.Both groups achieved significant hepatitis B virus (HBV) replication inhibition and alanine aminotransferase normalization at 48 wk. At the baseline, compared to healthy controls, CHB patients had a lower circulating CD8 T cell frequency (29.44% ± 11.55% vs 37.17% ± 7.30%, P = 0.03) and higher frequencies of programmed death 1 positive CD8 T cells (PD-1+ CD8 T) (16.48% ± 10.82% vs 7.02% ± 3.62%, P = 0.0001) and CD4+ CD25+ FoxP3+ T regulatory cells (Tregs) (23.64% ± 9.38% vs 13.60% ± 6.06%, P = 0.001). On therapy, at the beginning 24 wk with the levels of hepatitis B virus deoxyribonucleic acid (HBV DNA) and HBeAg declining, the frequencies of PD-1+ CD8 T cells and Treg cells gradually and significantly declined at 12 and 24 wk in both therapy groups. At treatment week 4, patients treated with LDT had a lower frequency of PD-1+ CD8 T cells compared to patients treated with LAM (10.08% ± 6.83% vs 20.51% ± 20.96%, P = 0.02). The frequency of PD-1+ CD8 T cells in all of the CHB patients was significantly correlated with both the HBV DNA level (r = 0.45, P = 0.01) and HBeAg level (r = 0.47, P = 0.01) at treatment week 24, but the frequency of Treg cells was only significantly correlated with the HBeAg level (r = 0.44,P = 0.02). Furthermore, the ability of CD8 T cells to secrete pro-inflammatory cytokines was partially restored after 24 wk of therapy.NA-mediated HBV suppression could down-regulate the production of negative regulators of host immunity during the first 24 wk of therapy and could partially restore the ability of CD8 T cells to secrete pro-inflammatory cytokines. This immune modulating response may be correlated with the levels of both HBV DNA and HBeAg.

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A ferrocene-containing nucleoside analogue targets DNA replication in pancreatic cancer cells.

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