NCAPG is transcriptionally regulated by CBX3 and activates the Wnt/β-catenin signaling pathway to promote proliferation and the cell cycle and inhibit apoptosis in colorectal cancer

BACKGROUND: Colorectal cancer (CRC) is highly heterogeneous at the genetic and molecular level and a major contributor to cancer-death worldwide. Non-structural maintenance of chromosomes (SMC) condensin I complex subunit G (NCAPG) is a subunit of condensin I and has been shown to be associated with the prognosis of cancers. This study investigated the functional role of NCAPG in CRC and its mechanism. METHODS: Messenger RNA (mRNA) and protein expressions of NCAPG and chromobox protein homolog 3 (CBX3) were determined by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot. The proliferation, cycle, and apoptosis of HCT116 cells were analyzed by Cell Counting Kit-8 (CCK-8), flow cytometry, and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay. RT-qPCR and western blot were used to determine the transfection efficacy of short hairpin (sh)-NCAPG and sh-CBX3. Western blot was used to explore cycle-, apoptosis-, and Wnt/β-catenin signaling-related proteins, and the activity of NCAPG promoter was evaluated using a luciferase report assay. The expressions of cleaved caspase9 and cleaved caspase3 were assessed by colorimetric caspase activity assay. RESULTS: The results showed that NCAPG expression was elevated in CRC cells. After transfection with sh-NCAPG, NCAPG expression was reduced. It was also discovered that NCAPG knockdown suppressed proliferation and the cell cycle but induced apoptosis in HCT116 cells. The Human Transcription Factor Database (HumanTFDB; http://bioinfo.life.hust.edu.cn/HumanTFDB#!/) predicted the binding sites of CBX3 and NCAPG promoters. Meanwhile, the Encyclopedia of RNA Interactomes (ENCORI) database (https://starbase.sysu.edu.cn/) revealed that CBX3 was positively correlated with NCAPG. Our results showed that NCAPG was transcriptionally regulated by CBX3. Additionally, Wnt/β-catenin signaling was discovered to be activated by CBX3 overexpression. Further experiments showed that NCAPG transcriptionally regulated by CBX3 activated Wnt/β-catenin signaling to regulate the proliferation, cell cycle, and apoptosis of HCT116 cells. CONCLUSIONS: Collectively, the results of our study indicated that NCAPG was transcriptionally regulated by CBX3 and activated the Wnt/β-catenin signaling pathway to facilitate the progression of CRC.