Long Non-Coding RNA LINC01569 Promotes Proliferation and Metastasis in Colorectal Cancer by miR-381-3p/RAP2A Axis

Background

Long non-coding RNAs (lncRNAs) display regulatory function flexibly in tumor onset and developments. Our study aimed to delve into the roles of lncRNA LINC01569 (LINC01569) in colorectal cancer (CRC) progression to study the potential mechanisms.

Methods

The genetic expression profiles of miR-381-3p and LINC01569 were measured by RT-PCR. The subcellular localization of LINC01569 in CRC cells was identified using subcellular fractionation location. Loss-of-function assays were performed to explore the potential effects of LINC01569 on CRC progression. Dual-luciferase reporter analysis was employed to verify the binding connections among LINC01569, miR-381-3p, and RAP2A.

Results

LINC01569 expression was distinctly increased in CRC. Curiously, if LINC01569 is removed, CRC cells will not migrate, proliferate, and invade remarkably. Molecular mechanism exploration uncovered that LINC01569 acted as a ceRNA competing with RAP2A to bind with miR-381-3p. Furthermore, rescue experiments corroborated the fact that miR-381-3p suppression reversed the inhibitory actions of LINC01569 knockdown on the expression of RAP2A and CRC progression.

Conclusion

Overall, our findings indicate that LINC01569 plays a key role in CRC development by means of aiming at the miR-381-3p/RAP2A axis and can be equivalent to an underlying medicinal target to save CRC patients.

Tumor suppressive role of miR-33a-5p in pancreatic ductal adenocarcinoma cells by directly targeting RAP2A

Background

The suppressive effects of miR-33a-5p have been reported in colorectal cancer and lung cancer. However, the functional role of miR-33a-5p in pancreatic ductal adenocarcinoma (PDAC) has not yet been elucidated.

Methods

The expression of miR-33a-5p was determined using reverse-transcription quantitative PCR (RT-qPCR) in PDAC tissues and cell lines. The association between miR-33a-5p expression and clinical categorical parameters was analyzed by the chi-square test. Cell proliferation was analyzing by Cell Counting Kit -8 (CCK-8) assay. Transwell assay was utilized to assess cell migration and invasion. The interactions between miR-33a-5p and RAP2A were verified by luciferase reporter assay, RT-qPCR, western blot analysis and RNA immunoprecipitation (RIP) assay.

Results

Here, we observed for the first time that miR-33a-5p expression level was significantly decreased in PDAC tissues and cell lines. There was a significant association between decreased miR-33a-5p expression and TNM stage or lymph node metastasis. Overexpression of miR-33a-5p significantly inhibited SW1990 and PANC-1 cell proliferation, migration and invasion. Knockdown of miR-33a-5p remarkedly promoted cell proliferation, migration and invasion in BxPC-3 and ASPC-1. Mechanistically, RAP2A was confirmed as the target of miR-33a-5p in PDAC cells. Moreover, RAP2A overexpression abolished miR-33a-5p-mediated suppressive effects on SW1990 and PANC-1 cells.

Conclusions

Taken together, these results suggest that miR-33a-5p exerted tumor suppressive effects on PDAC cells by targeting RAP2A, which might provide a new theoretical basis for the clinical treatment of PDAC.

RAP2A promotes apoptosis resistance of hepatocellular carcinoma cells via the mTOR pathway

Hepatocellular carcinoma (HCC) is the most common digestive system cancer. In the current study, we investigated the biological effects of Ras-related protein Rap-2a (RAP2A), a GTPase protein, in HCC tissues and cells. We found that RAP2A was upregulated in HCC tissues and cells. RAP2A knockdown could effectively inhibit the proliferation of HCC cells and weaken its apoptosis resistance. In terms of its action mechanism, RAP2A may be involved in activating the mTOR signaling pathway. Therefore, we believe that RAP2A is abnormally highly expressed in HCC tissues and promotes tumor cell proliferation and apoptosis resistance by activating the mTOR signaling pathway, and it may serve as a potential target for HCC treatment.

Metformin Decreases Insulin Resistance in Type 1 Diabetes Through Regulating p53 and RAP2A in vitro and in vivo

Purpose

Patients with type 1 diabetes (T1D) are associated with a high risk of multiple complications, so the development of T1D treatment is urgently needed. This study was set out to explore the molecular mechanism of metformin in the treatment of T1D insulin resistance.

Patients and Methods

Subcutaneous adipose tissues were collected from 68 T1D patients and 51 healthy controls. Insulin resistance model rats and cells were constructed and treated with metformin respectively. Western blot was used to detect p53 and RAP2A protein levels, and qPCR was utilized to measure p53 and RAP2A mRNA levels. SiRNA and RAP2A siRNA vectors were constructed to observe their effects on insulin resistance model cells.

Results

In T1D, p53 was up-regulated, while RAP2A was down-regulated. Metformin could effectively improve insulin resistance and inflammatory response while down-regulating p53 and up-regulating RAP2A. P53 induced insulin resistance and inflammatory response by inhibiting RAP2A and promoted apoptosis.

Conclusion

Metformin improves T1D insulin resistance and inflammatory response through p53/RAP2A pathway, and the regulation of p53/RAP2A pathway is conducive to improving the efficacy of metformin in the treatment of insulin resistance.

LINC00319-Mediated miR-3127 Repression Enhances Bladder Cancer Progression Through Upregulation of RAP2A

Recent studies suggested that microRNA-3127 (miR-3127) was dysregulated in multiple tumor types and has important roles in tumorigenesis and cancer progression. However, its biological roles and the mechanisms that regulate its expression in bladder cancer (BCA) remain to be determined. The expression level of miR-3127 was measured in BCA tissues and its cellular functions were examined using both in vitro and in vivo experiments. The interaction between miR-3127 and long non-coding RNA (lncRNA) LINC00319 was explored using RNA immunoprecipitation assay and luciferase reporter assays. We showed that miR-3127 expression was significantly downregulated in human BCA tissues and BCA cell lines. Lower miR-3127 levels were associated with worse survival in BCA patients. The overexpression of miR-3127 impaired BCA cell proliferation and invasion, and the knockdown of miR-3127 enhanced BCA cell proliferation and invasion in vitro. Importantly, miR-3127 was able to suppress cell growth in vivo. We demonstrated that miR-3127 repressed the proliferation and invasion of BCA cells though directly targeted the 3′-UTR of RAP2A, which served as a novel oncogene in BCA cells. The suppression of cell proliferation and invasion caused by miR-3127 overexpression could be partially abrogated by ectopic expression of RAP2A. Furthermore, high expression of LINC00319 was correlated with adverse survival in BCA patients. LINC00319 could bind directly with miR-3127 and inhibited its expression, and the tumor-promoting effects of LINC00319 could be reversed by re-expression of miR-3127 in BCA cells. Our findings indicated that lncRNA LINC00319-mediated miR-3127 repression promotes BCA progression through the upregulation of RAP2A. The re-introduction of miR-3127 or inhibition of LINC00319 might represent a promising therapeutic strategy for BCA treatment.

MiR-140 targets RAP2A to enable the proliferation of insulin-treated ovarian granulosa cells

BACKGROUND

We elucidated the role of specific MicroRNAs (miRNAs) in the development of polycystic ovary syndrome (PCOS) and explained the changes in the proliferation of granulosa cells. Excised ovarian cortex specimens were collected for miRNA profiling analysis (n = 20 PCOS females and 5 non-PCOS females). Insulin-treated ovarian granulosa cells isolated from mice were used for mechanical studies.

RESULTS

High miR-140 expression was observed in PCOS samples and insulin-treated granulosa cells compared to that in non-PCOS and unstimulated cells, respectively. However, the Ras-related protein Rap-2a precursor (RAP2A) was downregulated in in PCOS. MTT assay and EdU staining showed that an miR-140 inhibitor attenuated viability in insulin-treated granulosa cells; cell viability increased with miR-140 overexpression. Reduced expression of miR-140 and the expression of the miR-140 mimic resulted in marked cell apoptosis, as evidenced by the results of PI flow cytometry and Annexin V-FITC; miR-140 overexpression results in downregulated RAP2A expression, and the miR-140 mimic directly bound to the RAP2A 3'-UTR, causing increase in RAP2A levels in insulin-treated granulosa cells; RNA-mediated silencing of RAP2A in insulin-treated granulosa cells restored cell proliferation and apoptosis to normal levels. Phosphorylated AKT was found to be negatively regulated through cross-talk between miR-140 and RAP2A.

CONCLUSIONS

In conclusion, PCOS ovarian cortex specimens and insulin-treated granulosa cells showed elevated expression of miR-140, which could lead to increased proliferation and reduced apoptosis of cells by targeting RAP2A. This study may pave the way for future research on the properties of granulosa cells in PCOS.

The prognostic impact of RAP2A expression in patients with early and locoregionally advanced nasopharyngeal carcinoma in an endemic area

BACKGROUND

By data mining from published transcriptomic databases, we identified RAP2A as a significantly upregulated gene in nasopharyngeal carcinoma (NPC) tissues. RAP2A, a member of the RAS oncogene family, is involved in the process of GTP binding and GTPase activity. The aim of this study was to evaluate the expression of RAP2A and its prognostic impact in patients with early and locoregionally advanced NPC.

METHODS

RAP2A immunohistochemistry was performed for 124 NPC patients who were receiving standard treatment and had no initial distal metastasis. We also performed Western blotting to evaluate the endogenous protein expression of RAP2A in NPC cells and non-neoplastic mucosal cells. The result of RAP2A expression was further correlated with clinicopathological variables, disease-specific survival (DSS), distant metastasis-free survival (DMeFS), and local recurrence-free survival (LRFS).

RESULTS

High expression of RAP2A was significantly associated with advanced primary tumor status (P = 0.024) and advanced TNM stage (P = 0.006). In univariate analysis, high expression of RAP2A served as a significant prognostic factor for inferior DSS (P < 0.0001), DMeFS (P < 0.0001), and LRFS (P < 0.0001). In multivariate analysis, RAP2A overexpression still independently predicted worse DSS (hazard ratio [HR] = 2.976, P < 0.001), DMeFS (HR = 4.233, P < 0.001), and LRFS (HR = 4.156, P < 0.001). Moreover, Both HONE1 and TW01 NPC cells, but not non-neoplastic DOK cells demonstrated significantly increased RAP2A expression.

CONCLUSION

Overexpression of RAP2A is associated with advanced disease status and may therefore be an important prognosticator for poor outcomes in NPC, as well as a potential therapeutic target to aid in developing effective treatment modalities.