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Long noncoding RNA PiHL regulates p53 protein stability through GRWD1/RPL11/MDM2 axis in colorectal cancer.

ABSTRACT: We identified a novel long noncoding RNA (lncRNA) upregulated in colorectal cancer (CRC). We elucidated its role and clinical significance in CRC carcinogenesis. Methods: LncRNA candidates were identified using TCGA database. LncRNA expression profiles were studied by qRT-PCR and microarray in paired tumor and normal tissues. The independence of the signature in survival prediction was evaluated by multivariable Cox regression analysis. The mechanisms of lncRNA function and regulation in CRC were examined using molecular biological methods. Results: We identified a novel long noncoding gene (PiHL, P53 inHibiting LncRNA) from 8q24.21 as a p53 negative regulator. PiHL is drastically upregulated in CRC and is an independent predictor of CRC poor prognosis. Further in vitro and in vivo models demonstrated that PiHL was crucial in maintaining cell proliferation and inducing 5-FU chemoresistance through a p53-dependent manner. Mechanistically, PiHL acts to promote p53 ubiquitination by sequestering RPL11 from MDM2, through enhancing GRWD1 and RPL11 complex formation. We further show that p53 can directly bind to PiHL promoter and regulating its expression. Conclusion: Our study illustrates how cancer cells hijack the PiHL-p53 axis to promote CRC progression and chemoresistance. PiHL plays an oncogenic role in CRC carcinogenesis and is an independent prognostic factor as well as a potential therapeutic target for CRC patients.

SUBMITTER: Deng X

PROVIDER: S-EPMC6929633 | biostudies-literature | 2020

REPOSITORIES: biostudies-literature

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A recurrently amplified long noncoding RNA in colorectal cancer regulates p53 protein stability through GRWD1/RPL11/MDM2 axis [RNA-seq]

Project description:By integrating genome-wide copy number alteration, RNA-seq and proteomics data from 589 colorectal cancer (CRC) patients, we revealed that chromosome 8q24.21 amplification is negatively correlated with p53 protein stability. Using siRNA and CRISPR activation screening, we pinpointed a novel long noncoding gene (PiHL, P53 inHibiting LncRNA) from 8q24.21 as a p53 negative regulator. PiHL is drastically upregulated in CRC and is an independent predictor of CRC poor prognosis. Further In vitro and In vivo models demonstrate that PiHL is crucial in maintaining cell proliferation and inhibiting cell apoptosis through a p53-depedent manner. Mechanistically, PiHL acts to promote p53 ubiquitination by sequestering RPL11 from MDM2, through enhancing GRWD1 and RPL11 complex formation. We further show that p53 can form a feedback loop with PiHL by directly binding to PiHL promoter and regulating its expression. Our study successfully illustrates how cancer cells hijack the PiHL-p53 axis to promote CRC progression and suggests PiHL as a potential therapeutic target in human CRCs.

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