miR‐335 modulates Numb alternative splicing via targeting RBM10 in endometrial cancer

Abstract

Numb is a conserved protein plays important roles in the development of cancer. Two Numb isoforms have been found produced by alternative splicing and play contrast roles in regulating cellular functions. It is reported that the expression of Numb long isoform (Numb‐L) was increased in various kinds of cancers, but in endometrial cancer, the condition is still unknown. The level of two Numb transcripts and protein isoforms were detected by semiquantitative polymerase chain reaction and immunoblotting in 47 paired endometrial tumor and adjacent non‐tumor control tissues. The level of three alternative splicing related proteins: RBM5, RBM6, and RBM10 was determined by immunoblotting. MiRNAs targeting RBM10 were predicted by bioinformatics tools and their interaction with RBM10 was confirmed by luciferase assay and immunoblotting. The function of miR‐335 in endometrial cancer was examined in xenograft mouse model. Numb‐L level was increased in tumors and negatively correlated with RBM10 protein level. RBM10 mRNA level was not significantly altered in endometrial tumors suggesting its expression may regulated by post transcriptional regulators such as miRNAs. We identified miR‐133a, miR‐133b, and miR‐335 directly target RBM10, but only miR‐335 level increased in tumors and negatively correlated with RBM10 protein level. miR‐335 overexpression promoted tumor growth by downregulating RBM10 and upregulating Numb‐L level in xenograft mouse model. miR‐335 overexpression promoted Numb‐L expression via targeting RBM10 in endometrial cancer, which may provide new biomarkers for EC diagnosis.

MicroRNA as Epigenetic Modifiers in Endometrial Cancer: A Systematic Review

“…Improved diagnosis, risk assessment, and treatment strategies based on miRNA represents a promising area but will require future research. miR-193a-3p X [109] miR-193a-5p X [169] miR-193b X [129] miR-194 X X [128,179,180] miR-195 X [118,169] miR-196a-5p X [119] miR-196b X [169] miR-197 X [87] miR-198 X [169] miR-199a-5p X [169] miR-199b-5p X [117,125,169] miR-199b-3p X [125,169] miR-199b X [121] miR-299-5p X [169] miR-301 X [51,128] miR-302a-5p X [91] miR-320a X [33] miR-325 X [128] miR-326 X X [110,128] miR-328-3p X [119] miR-330 X [128] miR-330-3p X [169] miR-331 X [54] miR-331-3p X [69] miR-335 X [39] miR-337-3p X [119] miR-337-5p X [117,169] miR-340-5p X [33] miR-361 X [66] miR-363 X [129] miR-368 X [129] miR-369 X [126] miR-370 X [117] miR-371-5p X [169] miR-373 X [97] miR-375 X…”

RBM10 Regulates Tumor Apoptosis, Proliferation, and Metastasis

“…When RBM10 expression is downregulated, Numb is also downregulated, which can lead to the activation of the Notch pathway, enhanced HeLa cell lines colony formation, and promotion of tumor growth and proliferation ( 40 ). Additionally, miR-335 overexpression regulates the expression of Numb-L in endometrial carcinoma by targeting RBM10, providing a new biomarker for the diagnosis of endometrial cancer ( 41 ).…”

“…The miR-335 expression is increased in endometrial tumor tissues and negatively correlated with RBM10 protein levels. However, there was no significant change in the level of RBM10 mRNA, suggesting that the expression of RBM10 may be regulated by post-transcriptional regulatory factors such as miRNAs ( 41 ). Angiogenesis plays an essential role in the pathogenesis of gynecological diseases such as endometriosis and malignant tumor.…”

RBM10, a New Regulator of p53

“…Especially, RBM10 has been shown to act as a regulator of alternative splicing [34,117]. A recent study showed that miR-335 modulates Numb alternative splicing via targeting RBM10 in endometrial cancer [118]. In this family, RBM10 shares a highly similar RNA-binding motif and a 30-50% amino acid sequence identity, with two other members, RBM5 and RBM6 [35].…”

“…Mechanistically, RBM10 can induce tumor necrosis factor alpha (TNF-α) and apoptosis [132]. Moreover, it has been recently shown to suppress cancer cell proliferation through its function in alternative splicing of oncogenic mRNAs, such as NUMB [118] and VEGFA [32], or by inhibiting RAP1/AKT/CREB signaling [133]. Furthermore, our recent study showed that over expression of RBM10 reduces cancer cell migration and the EMT related gene Vimentin as well [134].…”