Identification of 7-aminourea or 7-aminothiourea derivatives of camptothecin as selective topoisomerase I inhibitors with anti-colorectal cancer activities.

Colorectal cancer (CRC) remains one of the most prevalent malignant tumors of the digestive system, yet the availability of safe and effective chemotherapeutic agents for clinical use remains limited. Camptothecin (CPT) and its derivatives, though approved for cancer treatment, have encountered significant challenges in clinical application due to their low bioavailability and high systemic toxicity. Strategic modification at the 7-position of CPT enables the development of novel CPT derivatives with high activity. In the present study, a series of compounds incorporating aminoureas, amino thioureas, and acylamino thioureas as substituents at the 7-position were screened. These compounds were subsequently evaluated for their cytotoxicity against the human gastric cancer (GC) cell line AGS and the CRC cell line HCT116. Two derivatives, XSJ05 (IC50 = 0.006 ± 0.003 µM) and XSJ07 (IC50 = 0.013 ± 0.003 µM), exhibited remarkably effective anti-CRC activity, being better than TPT. In addition, they have a better safety profile. In vitro mechanistic studies revealed that XSJ05 and XSJ07 exerted their inhibitory effects on CRC cell proliferation by suppressing the activity of topoisomerase I (Topo I). This suppression triggers DNA double-strand breaks, leads to DNA damage and subsequently causes CRC cells to arrest in the G2/M phase. Ultimately, the cells undergo apoptosis. Collectively, these findings indicate that XSJ05 and XSJ07 possess superior activity coupled with favorable safety profiles, suggesting their potential as lead compounds for the development of CRC therapeutics.

Synthesis and Biological Activity of 2-Chloro-8-methoxy-5-methyl-5H-indolo [2,3-b] Quinoline for the Treatment of Colorectal Cancer by Modulating PI3K/AKT/mTOR Pathways.

Developing novel drugs from natural products has proven to be a very effective strategy. Neocryptolepine was isolated from Cryptolepis sanguinolenta, a traditional endemic African herb, which exerts a wide range of biological activities such as antimalaria, antibacterial, and antitumor. 2-Chloro-8-methoxy-5-methyl-5H-indolo [2,3-b] quinoline (compound 49) was synthesized, and its cytotoxicity was assessed on pancreatic cancer PANC-1 cells, colorectal cancer HCT116 cells, liver cancer SMMC-7721 cells, and gastric cancer AGS cells in vitro. The results of the in vitro assay showed that compound 49 exerted remarkable cytotoxicity on colorectal cancer HCT116 and Caco-2 cells. The cytotoxicity of compound 49 to colorectal cancer HCT116 cells was 17 times higher than that of neocryptolepine and to human normal intestinal epithelial HIEC cells was significantly reduced. Compound 49 exhibited significant cytotoxicity against the colorectal cancer HCT116 and Caco-2 cells, with IC50 of 0.35 and 0.54 µM, respectively. The mechanism of cytotoxicity of compound 49 to colorectal cancer HCT116 and Caco-2 cells was further investigated. The results showed that compound 49 could inhibit colony formation and cell migration. Moreover, compound 49 could arrest the cell cycle at the G2/M phase, promote the production of reactive oxygen species, reduce mitochondrial membrane potential, and induce apoptosis. The results of Western blot indicated that compound 49 showed cytotoxicity on HCT116 and Caco-2 cells by modulating the PI3K/AKT/mTOR signaling pathway. In conclusion, these results suggested that compound 49 may be a potentially promising lead compound for the treatment of colorectal cancer.