Development of novel pyrimidine nucleoside analogs as potential anticancer agents: Synthesis, characterization, and In-vitro evaluation against pancreatic cancer

The present study proposed modification of 5 -FU by conjugation with an acyl chloride and a 5 -membered heterocyclic ring to improve its in -vitro cytotoxicity and metabolic stability. XYZ-I-71 and XYZ-I-73 were synthesized by introducing a tetrahydrofuran ring on 5-fluorocytosine (a precursor of 5 -FU) and conjugation with octanoyl chloride and lauroyl chloride, respectively. The structure of the synthesized compounds was validated using NMR and micro -elemental analysis. The antiproliferative activity of the analogs was determined against MiaPaCa-2, PANC-1, and BxPC-3 pancreatic cancer cells. The analog's stability in human liver microsomes was quantified by HPLC. We found that the XYZ-I-73 (IC 50 3.6 +/- 0.4 mu M) analog was most effective against MiaPaCa2 cells compared to XYZ-I-71(IC 50 12.3 +/- 1.7 mu M), GemHCl (IC 50 24.2 +/- 1.3 mu M), Irinotecan (IC 50 10.1 +/- 1.5 mu M ) and 5 -FU (IC 50 13.2 +/- 1.1 mu M ) . The antiproliferative effects of this analog in Miapaca-2 cells is evident based on it having a 7-fold,3-fold, and 4 -fold increased cytotoxic effect over Gem-HCl, Irinotecan, and 5 -FU, respectively. On the other hand, XYZ-I-71 exhibited a 2 -fold increased cytotoxic effect over Gem-HCl but a comparable cytotoxic effect to 5 -FU and Irinotecan in MiaPaCa-2 cells. A similar trend of higher XYZ-I-73 inhibition was observed in PANC-1 and BxPC-3 cultures. For 48-h MiaPaCa-2 cell migration studies, XYZ-I-73 (5 mu M) significantly reduced migration (# of migrated cells, 168 +/- 2.9), followed by XYZ-I-71(315 +/- 2.1), Gem-HCl (762 +/- 3.1) and 5 -FU (710 +/- 3.2). PARP absorbance studies demonstrated significant inhibition of PARP expression of XYZ-I73 treated cells compared to 5 -FU, GemHCl, and XYZ-I-71. Further, BAX and p53 expressions were significantly increased in cells treated with XYZ-I-73 compared to 5 -FU, GemHCl, and XYZ-I-71. In -vitro , metabolic stability studies showed that 80 +/- 5.9% of XYZ-I-71 and XYZ-I-73 remained intact after 2 h exposure in liver microsomal solution compared to 5 -FU. The XYZ-I-73 analog demonstrated a remarkable cytotoxic effect and improved invitro metabolic stability over the selected standard drugs and may have potential anticancer activity against pancreatic cancer.