<p>MiR-802 Suppresses Colorectal Cancer Cell Viability, Migration and Invasion by Targeting RAN</p>

Abstract

Purpose: Colorectal cancer is one of the most malignant tumors in the world, and the incidence is increasing every year. MicroRNAs (miRNA) are small non-coding RNAs that are involved in a variety of physiological or pathological processes. Abnormal expression of microRNA-802 (miR-802) has been demonstrated in various types of cancer. However, the expression and biological role of miR-802 in human colorectal cancer remain largely unknown. Methods: Here, we used quantitative real-time PCR (qRT-PCR) to measure miR-802 expression levels in colorectal cancer tissues and cell lines. Cell Counting Kit-8 (CCK-8) was used to assess the effect of miR-802 on colorectal cancer cell viability. Migration and invasion assays were performed to determine the effect of miR-802 on metastasis of colon tumor cells by transwell analysis. Luciferase activity assays were used to confirm the target of miR-802. Results: The results show that miR-802 is significantly downregulated in colorectal cancer tissues and cell lines. Overexpression of miR-802 profoundly inhibited viability, migration and invasion of colorectal cancer cells. In addition, we have newly discovered that the Rasassociated nucleus (RAN) is a direct target of miR-802 which could reverse the effects induced by miR-802 overexpression in colorectal cancer cells. Conclusion: In conclusion, our study shows that miR-802 is downregulated in colorectal cancer, and overexpression of miR-802 inhibits colorectal cancer cell viability, migration and invasion by directly targeting RAN.

LncRNA ANRIL Regulates Ovarian Cancer Progression and Tumor Stem Cell-Like Characteristics via miR-324-5p/Ran Axis

“… 43 Small GTPase Ran was a carcinogenic protein. Several miRNAs, including miR-802, miR-2, miR-197, miR-203 could directly bind to Ran to modulate cancer cell behaviors in cancers, 15 , 44–47 which indicated that Ran involved in the regulation of malignant behaviors in cancers. Until now, some articles have revealed the regulatory mechanism of Ran in ovarian cancer, including stem-like properties, 48 cell invasion, 49 cell survival, 50 and prognosis, 13 which further indicated the carcinogenic role of Ran in ovarian cancer.…”

<p>MicroRNA-802 Suppresses Tumorigenesis of Colorectal Cancer via Regulating UBN2</p>

“…Our results were consistent with the recent published study conducted by Wang et al, which showed that the low expression of miR-802 in CRC tissues was related to shorter patient's OS. 25 Together, these data suggest that miR-802 acts as tumor suppressor in CRC. The UBN2 protein is encoded by the UBN2 gene that is located on chromosome 7q34, 26 which belongs to the ubinuclein family and widely exists in human adult and fetal tissues.…”

Dysfunction of miR‐802 in tumors

“…In vitro experiments also further showed that miR-802 promoted the proliferation of lung cancer cells. 35 The abnormal expression of miR-802 has been confirmed in the tumor tissues or tumor cells of 15 cancers, including TSCC, 4 OSCC, 5,6 LSCC, 8 GC, [9][10][11] CRC, [12][13][14] PC, [30][31][32] HCC, [22][23][24][25] PCa, 2,33 bladder urothelial cancer, 26 BC, 15,16 CC, [17][18][19] EOC, 20 lung cancer, [34][35][36] osteosarcoma, 27,28 and melanoma. 21 To note, the abnormal expression of miR-802 in ESCC 7 and cholesteatoma 29 has only been confirmed in tumor cells.…”

“…Subsequent experiments further revealed that miR-802 expression can regulate a series of cell behaviors, including cell proliferatio n, 2,[7][8][9]11,[13][14][15]18,[20][21][22][24][25][26]28,29,31,[33][34][35] invasion, 4,6,[11][12][13][14]17,[19][20][21]33,34,36 metastasis, 2,6,7,[11][12][13][14]17,20,21,25,26,33,34,36 apoptosis, [8][9][10]13,...…”

“…Some studies have also confirmed the tumor suppressor effect of miR‐802 in mouse models. Existing studies have found that the expression of miR‐802 is decreased in at least 10 cancers, including TSCC, 4 OSCC, 5 , 6 ESCC, 7 LSCC, 8 GC, 9 , 10 , 11 CRC, 12 , 13 , 14 BC, 15 , 16 CC, 17 , 18 , 19 EOC, 20 and melanoma. 21 It is worth noting that the direction of abnormal expression of miR‐802 in the other 4 tumors is inconsistent.…”