P53-R273H mutation enhances colorectal cancer stemness through regulating specific lncRNAs

Abstract

Background TP53 is one of the most frequently mutated genes among all cancer types, and TP53 mutants occur more than 60% in colorectal cancer (CRC). Among all mutants, there are three hot spots, including p53-R175H, p53-R248W and p53-R273H. Emerging evidence attributes cancer carcinogenesis to cancer stem cells (CSCs). Long noncoding RNAs (lncRNAs) play crucial roles in maintaining the stemness of CSCs. However, it is unknown if mutant p53-regulated lncRNAs are implicated in the maintenance of CSC stemness. Methods RNA-sequencing (RNA-seq) and ChIP-sequencing (ChIP-seq) were used to trace the lncRNA network regulated by p53-R273H in HCT116 endogenous p53 point mutant spheroid cells generated by the somatic cell knock-in method. RT-qPCR was used to detect lncRNA expression patterns, verifying the bioinformatics analysis. Transwell, spheroid formation, fluorescence activated cell sorter (FACS), xenograft nude mouse model, tumor frequency assessed by extreme limiting dilution analysis (ELDA), Western blot assays and chemoresistance analysis were performed to elucidate the functions and possible mechanism of lnc273–31 and lnc273–34 in cancer stem cells. Results p53-R273H exhibited more characteristics of CSC than p53-R175H and p53-R248W. RNA-seq profiling identified 37 up regulated and 4 down regulated differentially expressed lncRNAs regulated by p53-R273H. Combined with ChIP-seq profiling, we further verified two lncRNAs, named as lnc273–31 and lnc273–34, were essential in the maintenance of CSC stemness. Further investigation illustrated that lnc273–31 or lnc273–34 depletion dramatically diminished colorectal cancer migration, invasion, cancer stem cell self-renewal and chemoresistance in vitro. Moreover, the absence of lnc273–31 or lnc273–34 dramatically delayed cancer initiation and tumorigenic cell frequency in vivo. Also, lnc273–31 and lnc273–34 have an impact on epithelial-to mesenchymal transition (EMT). Finally, lnc273–31 and lnc273–34 were significantly highly expressed in CRC tissues with p53-R273H mutation compared to those with wildtype p53. Conclusions The present study unveiled a high-confidence set of lncRNAs regulated by p53-R273H specific in colorectal CSCs. Furthermore, we demonstrated that two of them, lnc273–31 and lnc273–34, were required for colorectal CSC self-renewal, tumor propagation and chemoresistance. Also, the expression of these two lncRNAs augmented in colorectal cancer patient samples with p53-R273H mutation. These two lncRNAs may serve as promising predictors for patients with p53-R273H mutation and are vital for chemotherapy. Electronic supplementary material The online version of this article (10.1186/s13046-019-1375-9) contains supplementary material, which is available to authorized users.

Ginsenoside Rg3 inhibits the biological activity of SGC‐7901

“…Loss or mutation of the PTEN gene can lead to accelerated cell proliferation, decreased apoptosis and changes in cell migration and morphology, all of which contribute to tumor formation (Dillon & Miller, 2014). At present, abnormalities in PTEN have been confirmed to be closely related to the development, progression, and prognosis of glioma (Zhang et al, 2019), NSCLC (Shi et al, 2019), breast cancer (Xing et al, 2019), colon cancer (Liu et al, 2019) (Delma et al, 2019;Han, 2019;Zhao et al, 2019). In our study, treatment of SGC-7901 cells with ginsenoside Rg3 significantly increased p53 expression, leading to significant retention of SGC-7901 cells in G1 phase and a high rate of apoptosis.…”

Gain-of-Function Mutations in p53 in Cancer Invasiveness and Metastasis

“…In a murine xenotransplant model these lncRNAs dramatically accelerate tumorigenesis. Their expression is also significantly elevated in colorectal cancer patient tissues that bear R273H mutation in p53 [58].…”

Targeting Long Non-coding RNA to Therapeutically Regulate Gene Expression in Cancer

“… 89 In recent years, more and more studies have shown that lncRNAs are widely involved in DNA methylation, histone modification, chromatin remodeling, and other biological processes in vivo , which can directly interact with transcription factors, functional RNA molecules, and chromatin remodeling modifiers, and regulate the expression of target genes at the epigenetic, transcribed, and post-transcribed levels. 90 , 91 , 92 , 93 In vivo , lncRNAs are mainly used as signaling molecules, bait molecules, guiding molecules, and scaffold molecules to perform biological functions. 94 In addition, some lncRNAs have diversity in the mode of action and can participate in gene expression regulation in a variety of ways at the same time.…”