S camptothecin cpt

The following four mutagens with different mechanisms of action were used to study the modulatory effect of BA on DNA damage: (i) methyl methanesulfonate (MMS; Sigma-Aldrich) dissolved in phosphate-buffered saline (PBS) at a concentration of 400 μM [11 (link)]. MMS is a direct-acting monofunctional alkylating agent that reacts with the DNA molecule by transferring methyl radicals [12 (link)]; (ii) doxorubicin (DXR; Eurofarma Laboratórios Ltda.) dissolved in sterile distilled water and used at a concentration of 0.3 μM [13 (link)]. DXR, one of the most potent broad-spectrum antitumor anthracycline antibiotics, is a free radical generator and a potent inhibitor of topoisomerase II [14 (link)]; (iii) (S)-(+)-camptothecin (CPT; Sigma-Aldrich) dissolved in DMSO (Sigma-Aldrich) at a concentration of 123.4 μM CPT acts by inhibiting topoisomerase I, an enzyme necessary for DNA replication [15 (link)]; (iv) etoposide (VP-16; Sigma-Aldrich) dissolved in DMSO at a concentration of 1.7 μM. VP-16 is a potent anticancer agent that inhibits topoisomerase II [16 (link)].

Synthesis of IAZA [12 (link)], FAZA [13 ] and azidoazomycin arabinofuranoside (N₃-AZA) [20 ] have been described previously. IAZA, FAZA, N₃-AZA and Ferrostatin-1 (SML0583, Sigma-Aldrich, Oakville, ON) were prepared as 500 mM solutions in DMSO and stored at −20 °C. N-Acetyl-l-cysteine (NAC; A7250, Sigma-Aldrich) was dissolved in 1:1 ratio of DMSO and distilled H₂O to prepare a fresh 250 mM stock solution for each experiment and added to medium to a final concentration of 3 mM; medium was buffered to ∼pH 7.4 before adding to cells. Stock solutions of 1 M hydroxyurea (HU; H8627, Sigma-Aldrich) and 10 mM (S)-(+)-Camptothecin (CPT; C9911, Sigma-Aldrich) were prepared in DMSO and kept at −20 °C.

Etoposide (VP-16), teniposide (VM-26), 5-Fluorouracil (5-FU), doxorubicin hydrochloride (DXR), cytosine β-D-arabinofuranoside (Ara-C), methotrexate hydrate (MTX), cyclophosphamide monohydrate), Cisplatin and (S)-(+)-Camptothecin (CPT), 3-[4,5-Dimethyl-thizol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) were pursed from Sigma-Aldrich Co., St. Louis MO. Drugs were dissolved in dimethyl sulfoxide to 100 mM stock solutions that were stored at 4°C. These were diluted in water to 1 mM working stocks prior to the assays.