Chiral hydroxymethyl-1H,3H-pyrrolo[1,2-c]thiazoles: the search for selective p53-activating agents for colorectal cancer therapy.

MANIO is an efficient p53-activating anticancer agent with remarkable selectivity to the p53 pathway and promising antitumor activity against colorectal cancer (CRC). Herein, a library of novel MANIO derivatives, including hydroxymethyl- and bis(hydroxymethyl)-1H,3H-pyrrolo[1,2-c]thiazoles, was synthesized by rational structural modulation. The antiproliferative activity of twenty derivatives was evaluated in a panel of human CRC cells with different p53 status. From this library, five compounds with R- and S-configuration and with aromatic or heteroaromatic groups at position 3, including the enantiomer of MANIO, were identified as selective towards p53-expressing cancer cells. On the other hand, two compounds with S-configuration, 6-hydroxymethyl- and 7-hydroxymethyl-5-methyl-3-phenyl-1H,3H-pyrrolo[1,2-c]thiazoles, showed high cytotoxicity against WTp53-expressing HCT116 colon cells but, unlike MANIO, exhibited p53-independent inhibitory activity in CRC. The results described provide relevant structural and pharmacophoric data for the design of new p53-activating agents for precision therapy of CRC or other p53-related cancers harboring both wild-type or mutated p53 forms.

3-(1,2,3-Triazol-4-yl)-ß-Carbolines and 3-(1H-Tetrazol-5-yl)-ß-Carbolines: Synthesis and Evaluation as Anticancer Agents.

Herein, the synthesis and anticancer activity evaluation of a series of novel ß-carbolines is reported. The reactivity of nitrosoalkenes towards indole was explored for the synthesis of novel tryptophan analogs where the carboxylic acid was replaced by a triazole moiety. This tryptamine was used in the synthesis of 3-(1,2,3-triazol-4-yl)-ß-carbolines via Pictet-Spengler condensation followed by an oxidative step. A library of compounds, including the novel 3-(1,2,3-triazol-4-yl)-ß-carbolines as well as methyl ß-carboline-3-carboxylate and 3-tetrazolyl-ß-carboline derivatives, was evaluated for their antiproliferative activity against colorectal cancer cell lines. The 3-(1H-tetrazol-5-yl)-ß-carbolines stood out as the most active compounds, with values of half-maximal inhibitory concentration (IC50) ranging from 3.3 µM to 9.6 µM against colorectal adenocarcinoma HCT116 and HT29 cell lines. The results also revealed a mechanism of action independent of the p53 pathway. Further studies with the 3-tetrazolyl-ß-carboline derivative, which showed high selectivity for cancer cells, revealed IC50 values below 8 µM against pancreatic adenocarcinoma PANC-1, melanoma A375, hepatocarcinoma HEPG2, and breast adenocarcinoma MCF-7 cell lines. Collectively, this work discloses the 3-tetrazolyl-ß-carboline derivative as a promising anticancer agent worthy of being further explored in future works.