Integrated activity-guided isolation and transcriptomic analysis reveal the therapeutic mechanism of Thonningianin A from Penthhorum chinense Pursh against colorectal cancer via p21 modulation.

Ethnopharmacological relevance: Pentrhothrum chinense Pursh (PCP) is a traditional Hmong dual-purpose medicinal plant that is known for its efficacy in activating blood circulation and removing blood stasis, protecting the liver, diuretic and anti-yellowing, and promoting digestion. It is commonly used for lowering blood glucose, protecting kidneys, antioxidant, anti-inflammatory, antibacterial, and has great potential in regulating the intestinal microenvironment and treating cancer. However, relatively few studies have been conducted on its material basis and mechanism of action in colorectal cancer (CRC) treatment.

Aim of the study: Identification of the key therapeutic active ingredients in PCP for CRC through in vitro and in vivo experiments, and unraveling and validating their main mechanisms of action in CRC therapy.

Materials and methods: Initially, key active compounds were isolated and identified from PCP using SPE, HPLC, and UPLC-MS. In vitro and in vivo experiments demonstrated that the compound inhibits proliferation, migration, and cell cycle progression in HCT116 and HT29 cells, and exhibited tumor-suppressive efficacy in an HT29 nude mouse xenograft model. Finally, the molecular mechanism of CRC treatment was elucidated by combining RNA-seq, TCGA database and siRNA knockdown assay.

Results: The key active ingredient of CRC inhibition in PCP was identified as Thonningianin A (TA) by isolation and extraction techniques combined with cellular experiments, and then in vitro experiments showed that TA dose-dependently inhibited the proliferation, migration and clone formation of CRC cells and induced G1-phase blockage, and in vivo experiments showed that high doses of TA significantly inhibited the growth of tumors in nude mice, which further confirmed the therapeutic effect of TA in CRC treatment. Subsequently, in combination with RNA-seq and online pharmacology database, it was found that TA specifically activated oncogene p21/CDKN1A, and its knockdown reversed TA-induced cycle block and proliferation inhibition, and the low expression of p21 in CRC was further confirmed by TCGA data.

Conclusion: It is clear that TA is the key active ingredient of PCP against CRC, and its up-regulation of p21 expression induces G1-phase blockade and inhibits tumor progression.