NKD1 targeting PCM1 regulates the therapeutic effects of HHT on colorectal cancer cells

Abstract Background: Colorectal cancer (CRC) is the most common primary malignancy. Homoharringtonine (HHT) has potential therapeutic effects on solid tumors. However, the regulatory target and mechanism of HHT in CRC progression remain elusive. Methods: CCK-8, Edu staining, flow cytometry and Western blotting assay to detect the effect of HHT on proliferation and apoptosis of CRC cells. Transcriptome sequencing screened the drug delivery target of HHT. In vitro rescue experiment and in vivo tumorigenesis experiment detect the targeted interaction between HHT and NKD1. Quantitative proteomics combined with CO-IP and IF experiments to verify the targeted interaction between NKD1 and PCM1. Results: HHT suppressed CRC cells proliferation by inducing cell cycle arrest and apoptosis in vitro and vivo. HHT inhibited NKD1 expression in a concentration and time dependent manner. NKD1 was overexpressed in CRC and its depletion enhanced the therapeutic sensitivity of HHT on CRC, which indicating that NKD1 plays an important role in the development of CRC as the drug delivery target of HHT. Furthermore, proteomic analysis revealed that PCM1 participated the process of NKD1-regulated cell proliferation and cell cycle. NKD1 interacted with PCM1 and promotes PCM1 degradation through the ubiquitin-proteasome pathway. The overexpression of PCM1 effectively reversed the inhibition of siNKD1 on cell cycle. Conclusions: These results suggested that NKD1 targeting PCM1 to participate in regulating the therapeutic effects of HHT on CRC. Our findings provide evidence for clinical application of NKD1-targeted therapy in improving HHT sensitivity for CRC treatment