Methylation of NRIP3 Is a Synthetic Lethal Marker for Combined PI3K and ATR/ATM Inhibitors in Colorectal Cancer
Meiying Zhang1, Xiaoyun Li1,2, James G Herman3
1Department of Gastroenterology & Hepatology, the First Medical Center, Chinese PLA General Hospital, Beijing, China.
Introduction:
The aim of this study was to investigate the epigenetic regulation and underlying mechanism of NRIP3 in colorectal cancer (CRC).
Methods:
Eight cell lines (SW480, SW620, DKO, LOVO, HT29, HCT116, DLD1, and RKO), 187 resected margin samples from colorectal cancer tissue, 146 cases with colorectal adenomatous polyps, and 308 colorectal cancer samples were used. Methylation-specific PCR, Western blotting, RNA interference assay, and a xenograft mouse model were used.
Results:
NRIP3 exhibited methylation in 2.7% (5/187) of resected margin samples from colorectal cancer tissue, 32.2% (47/146) of colorectal adenomatous polyps, and 50.6% (156/308) of CRC samples, and the expression of NRIP3 was regulated by promoter region methylation. The methylation of NRIP3 was found to be significantly associated with late onset (at age 50 years or older), poor tumor differentiation, lymph node metastasis, and poor 5-year overall survival in CRC (all P < 0.05). In addition, NRIP3 methylation was an independent poor prognostic marker ( P < 0.05). NRIP3 inhibited cell proliferation, colony formation, invasion, and migration, while induced G1/S arrest. NRIP3 suppressed CRC growth by inhibiting PI3K-AKT signaling both in vitro and in vivo . Methylation of NRIP3 sensitized CRC cells to combined PI3K and ATR/ATM inhibitors.
Discussion:
NRIP3 was frequently methylated in both colorectal adenomatous polyps and CRC. The methylation of NRIP3 may potentially serve as an early detection, late-onset, and poor prognostic marker in CRC. NRIP3 is a potential tumor suppressor. NRIP3 methylation is a potential synthetic lethal marker for combined PI3K and ATR/ATM inhibitors.
Insights
NRIP3 gene methylation is frequent in colorectal polyps and cancer, correlating with poor prognosis and late onset. Methylated NRIP3 acts as a tumor suppressor and a marker for targeted therapies.
Area of Science:
- Epigenetics
- Molecular Oncology
- Cancer Biology
Background:
- Colorectal cancer (CRC) poses a significant global health challenge.
- Understanding epigenetic alterations is crucial for early detection and targeted treatment of CRC.
Purpose of the Study:
- To investigate the epigenetic regulation of NRIP3 in colorectal cancer.
- To elucidate the underlying mechanisms of NRIP3 in CRC development and progression.
Main Methods:
- Analysis of NRIP3 methylation in 8 cell lines, 187 CRC tissues, 146 polyps, and 308 CRC samples.
- Utilized methylation-specific PCR, Western blotting, RNA interference, and a xenograft mouse model.
Main Results:
- NRIP3 promoter methylation was observed in 2.7% of CRC tissues, 32.2% of polyps, and 50.6% of CRC samples.
- NRIP3 methylation correlated with late onset, poor differentiation, lymph node metastasis, and reduced 5-year survival in CRC.
- NRIP3 suppressed CRC proliferation, invasion, and migration by inhibiting PI3K-AKT signaling, and sensitized cells to PI3K and ATR/ATM inhibitors.
Conclusions:
- NRIP3 methylation is a frequent event in colorectal polyps and CRC, potentially serving as an early detection and prognostic marker.
- NRIP3 functions as a tumor suppressor in CRC.
- NRIP3 methylation represents a potential synthetic lethal marker for combined PI3K and ATR/ATM inhibitor therapy.
