Dataset Information

A novel protein encoded by circINSIG1 reprograms cholesterol metabolism by promoting the ubiquitin-dependent degradation of INSIG1 in colorectal cancer.

ABSTRACT:

Background

Hypoxia is a hallmark of solid tumors and leads to the metabolic reprogramming of cancer cells. The role of epigenetic regulation between hypoxia and aberrant cholesterol metabolism in colorectal cancer (CRC) remains elusive.

Methods

Hypoxia-responsive circular RNAs (circRNAs) were identified by high throughput RNA sequencing between CRC cells cultured under normoxia or hypoxia. The protein-coding potential of circINSIG1 was identified by polysome profiling and LC-MS. The function of circINSIG1 was validated in vitro and in vivo by gain or loss of function assays. Mechanistic results were concluded by immunoprecipitation analyses.

Results

A novel hypoxia-responsive circRNA named circINSIG1 was identified, which was upregulated in CRC tissues and correlated with advanced clinical stages and poor survival. Mechanistically, circINSIG1 encoded a 121 amino acid protein circINSIG1-121 to promote K48-linked ubiquitination of the critical cholesterol metabolism regulator INSIG1 at lysine 156 and 158 by recruiting CUL5-ASB6 complex, a ubiquitin E3 ligase complex, thereby inducing cholesterol biosynthesis to promote CRC proliferation and metastasis. The orthotopic xenograft tumor models and patient-derived xenograft models further identified the role of circINSIG1 in CRC progression and potential therapeutic target of CRC.

Conclusions

circINSIG1 presents an epigenetic mechanism which provides insights into the crosstalk between hypoxia and cholesterol metabolism, and provides a promising therapeutic target for the treatment of CRC.

SUBMITTER: Xiong L

PROVIDER: S-EPMC10122405 | biostudies-literature | 2023 Apr

REPOSITORIES: biostudies-literature

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Publications

A novel protein encoded by circINSIG1 reprograms cholesterol metabolism by promoting the ubiquitin-dependent degradation of INSIG1 in colorectal cancer.

Xiong Li L Liu Hua-Shan HS Zhou Chi C Yang Xin X Huang Liang L Jie Hai-Qing HQ Zeng Zi-Wei ZW Zheng Xiao-Bin XB Li Wen-Xin WX Liu Zhan-Zhen ZZ Kang Liang L Liang Zhen-Xing ZX

Molecular cancer 20230422 1

<h4>Background</h4>Hypoxia is a hallmark of solid tumors and leads to the metabolic reprogramming of cancer cells. The role of epigenetic regulation between hypoxia and aberrant cholesterol metabolism in colorectal cancer (CRC) remains elusive.<h4>Methods</h4>Hypoxia-responsive circular RNAs (circRNAs) were identified by high throughput RNA sequencing between CRC cells cultured under normoxia or hypoxia. The protein-coding potential of circINSIG1 was identified by polysome profiling and LC-MS. T ...[more]

PMID: 37087475

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Project description:BackgroundUbiquitin E3 ligase CUL4A plays important oncogenic roles in the development of cancers. DTL, one of the CUL4-DDB1 associated factors (DCAFs), may involve in the process of cancer development. Programmed cell death 4 (PDCD4) is a tumor suppressor gene involved in cell apoptosis, transformation, invasion and tumor progression.MethodsAffinity-purification mass spectrometry was used to identify potential DTL interaction proteins. Co-immunoprecipitation (Co-IP) was performed to verify protein interaction between DTL and PDCD4. mRNA levels in cancer cells and tissues were detected by Quantitative real-time PCR. Lentivirus was used to establish stable overexpression and knocking down cell lines for DTL and PDCD4. Transwell and wound healing assays were used to determine migration ability of cancer cells. Matrigel assay was used to determine invasion ability of cancer cells. MTT and colony formation assays were used to evaluate proliferation of cancer cells.ResultsIn this study, programmed cell death 4 (PDCD4) was identified as a potential substrate of DTL. Co-IP and immunofluorescence assays further confirmed the interaction between DTL and PDCD4. Moreover, DTL overexpression decreased the protein level and accelerated the degradation rate of PDCD4. Through in vitro ubiquitination experiment, we proved that PDCD4 was degraded by DTL through ubiquitination. Clinically DTL was significantly up-regulated in cancer tissues than that in normal tissues. The survival curves showed that cancer patients with higher DTL expression owned lower survival rate. Functional experiments showed that DTL not only enhanced the proliferation and migration abilities of cancer cells, but also promoted the tumorigenesis in nude mice. Rescued experiment results demonstrated that silencing PDCD4 simultaneous with DTL recovered the phenotypes defect caused by DTL knocking down.ConclusionsOur results elucidated that DTL enhanced the motility and proliferation of cancer cells through degrading PDCD4 to promote the development of cancers.

Dataset Information

A novel protein encoded by circINSIG1 reprograms cholesterol metabolism by promoting the ubiquitin-dependent degradation of INSIG1 in colorectal cancer.

Background

Methods

Results

Conclusions

Publications

A novel protein encoded by circINSIG1 reprograms cholesterol metabolism by promoting the ubiquitin-dependent degradation of INSIG1 in colorectal cancer.

Similar Datasets

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