Extracellular vesicle expansion of PMIS‐miR‐210 expression inhibits colorectal tumour growth via apoptosis and an XIST/NME1 regulatory mechanism

Abstract

Background Colorectal cancer (CRC) has a high mortality rate, and therapeutic approaches to treat these cancers are varied and depend on the metabolic state of the tumour. Profiles of CRC tumours have identified several biomarkers, including microRNAs. microRNA‐210 (miR‐210) levels are directly correlated with CRC survival. miR‐210 expression is higher in metastatic colon cancer cells versus non‐metastatic and normal colon epithelium. Therefore, efficient methods to inhibit miR‐210 expression in CRC may provide new advances in treatments. Methods Expression of miRs was determined in several metastatic and non‐metastatic cell lines. miR‐210 expression was inhibited using PMIS‐miR‐210 in transduced cells, which were transplanted into xenograft mice. In separate experiments, CRC tumours were allowed to grow in xenograft mice and treated with therapeutic injections of PMIS‐miR‐210. Molecular and biochemical experiments identified several new pathways targeted by miR‐210 inhibition. Results miR‐210 inhibition can significantly reduce tumour growth of implanted colon cancer cells in xenograft mouse models. The direct administration of PMIS‐miR‐210 to existing tumours can inhibit tumour growth in both NSG and Foxn1nu/j mouse models and is more efficacious than capecitabine treatments. Tumour cells further transfer the PMIS‐miR‐210 inhibitor to neighbouring cells by extracellular vesicles to inhibit miR‐210 throughout the tumour. miR‐210 inhibition activates the cleaved caspase 3 apoptotic pathway to reduce tumour formation. We demonstrate that the long non‐coding transcript XIST is regulated by miR‐210 correlating with decreased XIST expression in CRC tumours. XIST acts as a competing endogenous RNA for miR‐210, which reduces XIST levels and miR‐210 inhibition increases XIST transcripts in the nucleus and cytoplasm. The increased expression of NME1 is associated with H3K4me3 and H3K27ac modifications in the NME1 proximal promoter by XIST. Conclusion Direct application of the PMIS‐miR‐210 inhibitor to growing tumours may be an effective colorectal cancer therapeutic.

Pan-Cancer Analysis of Non-Metastatic Cells 1: Its Biological Function and Prognostic Significance in Urological Tumors

“…Therefore, the NME1 gene family exhibits multifunctionality, and its impact on metastatic progression may be contradictory in various cancers. Previous studies have found that the expression of NME1 is negatively correlated with metastatic potential in melanoma and epithelial tumors such as breast, liver, colon, and cervical cancer [3,[23][24][25][26] . However, in hematological malignancies such as ovarian and prostate cancer, the opposite relationship is observed, where upregulation of NM23-H1 is associated with poor prognosis [27,28] .…”

“…However, few studies have identified the functional connection between NME1 and genitourinary tumor development. Although NME1 has been shown to be upregulated in melanoma [25] , its detailed role and potential mechanisms in genitourinary tumors remain unclear and require further research. Our study revealed that amplification and mutations are the main mutation types of NME1, which can be observed in melanoma, infiltrating breast cancer, mesothelioma, pancreatic adenocarcinoma, and esophageal adenocarcinoma.…”

RNA Technology to Regenerate and Repair Alveolar Bone Defects

“…The PMIS-miR-200a transgenic mice have increased craniofacial bone volume and density and miR-200a regulates the osteogenic program (Hong et al 2021; Su et al 2022). We have shown that direct injection of highly purified plasmid DNA expressing a PMIS-miR construct into tissues resulted in efficient PMIS-miR expression (Eliason et al 2022). It is well known that cells will endocytose and express genes from highly purified naked plasmid DNA, which applies both in vivo and in vitro (Braun 2004; Wolff and Budker 2005).…”

“…In total, 2 µg total RNA was used to generate complementary DNAs (cDNAs) using Takara Primescript for genes and Takara MirX for miRNAs. Quantitative real-time polymerase chain reaction (RT-qPCR) was performed as described previously (Eliason et al 2022). The cells were washed twice with phosphate-buffered saline (PBS) and then transfected with plasmid DNA (pDNA) encoding miR-200a at 5 μg/mL in serum-free medium (Opti-MEM; Life Technologies) with PEI for 18 h. EV was used as a control for nonspecific effects.…”

“…The plasmid-based miR inhibitor system (PMIS) was developed as a miR inhibitor system to determine the molecular function of miRs in primary human cells and mouse models (Cao et al 2016; Ries et al 2017; Hong et al 2021; Sweat et al 2021; Eliason et al 2022). PMIS modulates miR function by expressing a small 122-nucleotide noncoding RNA molecule that contains a specific antisense mature miR sequence.…”