PRAF2 expression indicates unfavorable clinical outcome in hepatocellular carcinoma

PRAF2 is an oncogene acting to promote the proliferation and invasion of breast cancer cells

Prenylated rab acceptor 1 domain family member 2 (PRAF2) acts as an oncogene and is closely related to the occurrence and development of various tumors. The present study aimed to clarify the functional relevance of PRAF2 in the biological behaviors of breast cancer by determining the expression of PRAF2 in breast cancer tissues and the corresponding adjacent tissues. The gene phenotypes of PRAF2 in patients with breast cancer in The Cancer Genome Atlas database were predicted using a cancer data online analysis website: The University of Alabama at Birmingham Cancer Data Analaysis Portal (UALCAN). The mRNA and protein expression of PRAF2 was further examined in 37 pairs of fresh frozen breast cancer tissues and adjacent non-tumor tissues by reverse transcription-quantitative PCR (RT-qPCR) and western blotting. High expression of PRAF2 was verified by RT-qPCR in the breast cancer cell line, MCF-7, and small interfering RNA (siRNA) technology was used to silence PRAF2. In the in vitro cell functional experiment, three groups were used: Negative control (NC) group, siRNA-NC group and siRNA-PRAF2 group. Cell Counting Kit-8 (CCK-8) and colony formation assays were conducted to analyze the effect of downregulation of PRAF2 on the proliferation of breast cancer cells. Transwell invasion and cell scratch assays were performed to examine the effect of downregulation of PRAF2 on the invasion and migration of breast cancer cells. UALCAN analysis results indicated that PRAF2 expression was upregulated in breast cancer compared with normal tissue samples (P<0.001). High expression of PRAF2 in breast cancer was associated with TNM stage and regional lymph node metastasis. RT-qPCR results showed increased mRNA expression of PRAF2 in clinical tissue samples from 37 patients with breast cancer, compared with normal adjacent tissues (P<0.001). Protein expression of PRAF2 was also shown to be higher in the breast cancer MCF-7 cells than in the MDA-MB-231 cells. Western blotting analysis combined with ImageJ software quantification showed that the relative expression of PRAF2 protein was significantly higher in clinical tissue samples from 37 patients with breast cancer (1.9750±0.0103) than that in normal adjacent tissues (0.9818±0.0140) (P<0.001). Western blotting analysis results indicated that transfection with siRNA PRAF2 in MCF-7 cells decreased PRAF2 expression (P<0.001). The results of CCK-8 and colony formation assays revealed that downregulation of PRAF2 expression suppressed the proliferation of MCF-7 cells (P<0.05 and P<0.001, respectively). In addition, Transwell invasion and cell scratch assay results showed that downregulation of PRAF2 expression in MCF-7 cells repressed invasion and migration of cancer cells (P<0.001). Overall, PRAF2 expression was significantly higher in breast cancer tissues than normal adjacent tissues, and was closely related to TNM stage and regional lymph node metastasis in breast cancer. PRAF2 was found to act as an oncogene that is able to promote breast cancer cell proliferation and invasion. Thus, PRAF2 may be a potential prognostic factor in patients with breast cancer and a potential target for the treatment of breast cancer metastasis.

Grape Seed Proanthocyanidins (GSPs) Inhibit the Development of Cutaneous Squamous Cell Carcinoma by Regulating the hsa_circ_0070934/miR-136-5p/PRAF2 Axis

Background

Grape seed proanthocyanidins (GSPs) have been shown to inhibit the progression of many cancers, including cutaneous squamous cell carcinoma (CSCC). Circular RNA (circRNA) is a key regulator for cancer progression. However, it is unclear whether GSPs can mediate the progression of CSCC by regulating circRNA.

Methods

Quantitative real-time PCR was conducted to determine the expression of hsa_circ_0070934, microRNA (miR)-136-5p and prenylated Rab acceptor family 2 (PRAF2). MTT assay and colony formation assay were used to assess cell proliferation. Cell cycle process and apoptosis were detected by flow cytometry, and cell migration and invasion were measured by transwell assay. Western blot analysis was utilized to examine protein expression. In addition, dual-luciferase reporter assay and RIP assay were used to evaluate the interaction between miR-136-5p and hsa_circ_0070934 or PRAF2. Subcutaneous xenograft models were constructed to explore the function of GSPs on CSCC tumor growth in vivo.

Results

GSPs could reduce hsa_circ_0070934 expression and inhibit CSCC cell proliferation, cell cycle process, migration, invasion, while promote apoptosis. Overexpressed hsa_circ_0070934 could reverse the suppressive effect of GSPs on CSCC cell progression. MiR-136-5p could be sponged by hsa_circ_0070934, and its overexpression also abolished the positively regulation of hsa_circ_0070934 on the progression of GSPs-induced CSCC cells. PRAF2 was a target of miR-136-5p, and its expression could be decreased by GSPs and increased by hsa_circ_0070934. The inhibitory effect of miR-136-5p on CSCC cell progression could be reversed by PRAF2 overexpression. Additionally, GSPs also could inhibit CSCC tumor growth in vivo.

Conclusion

Our data showed that GSPs regulated the hsa_circ_0070934/miR-136-5p/PRAF2 axis to restrain CSCC progression.

JHDM1D-AS1 aggravates the development of gastric cancer through miR-450a-2-3p-PRAF2 axis

AIMS

To investigate the molecular function and mechanisms of JHDM1D antisense 1 (JHDM1D-AS1) during gastric cancer (GC) progression.

MATERIALS AND METHODS

The qPCR assay was used to detect the JHDM1D-AS1 and miR-450a-2-3p expression levels in GC tissues and cell lines. Bioinformatics analysis was used for exploring the lncRNA-microRNA-mRNA interaction network. We performed dual-luciferase reporter assay and qPCR assay in order to validate the direct interactions. We explored the JHDM1D-AS1 and miR-450a-2-3p on GC progression by using JHDM1D-AS1 siRNA and miR-450a-2-3p inhibitor; in vitro CCK-8 assay, colony formation assay, and invasion assay were conducted. Further, in vivo animal experiments were performed, and the expression levels of miR-450a-2-3p and PRAF2 in the tumor tissues were detected using qPCR and western blot analysis.

KEY FINDINGS

The expression levels of JHDM1D-AS1 and miR-450a-2-3p in GC tissues and cell lines were higher and lower as compared to those in the corresponding normal controls, respectively. Moreover, high levels of JHDM1D-AS1 were closely related with metastasis and the GC TNM stage. Functionally, JHDM1D-AS1 depletion caused an obvious reduction in cell proliferation and invasion both in vitro and in vivo, while the addition of miR-450a-2-3p inhibitor could nullify these effects. Mechanically, JHDM1D-AS1 promoted GC progression via the sponging of miR-450a-2-3p in order to increase PRAF2 expression.

SIGNIFICANCE

The present results showed that the increased expression of JHDM1D-AS1 was closely associated with tumor progression of GC. JHDM1D-AS1/miR-450a-2-3p/PRAF2 axis may be a promising target for GC treatment.

Long non-coding RNA HOTAIR functions as a competitive endogenous RNA to regulate PRAF2 expression by sponging miR-326 in cutaneous squamous cell carcinoma

Background

LncRNAs may exert a regulatory effect in tumorigenesis. Although the expression of lncRNA HOTAIR has been confirmed to be notably elevated in the tissues of CSCC, its biological mechanism in CSCC is still unknown.

Methods

HOTAIR expression level in CSCC cell lines was monitored via qRT-PCR. Then CCK-8 assay, Transwell assay and EdU assay were adopted to detect cell migration and proliferation. Meanwhile, through bioinformatics analysis and luciferase reporter gene detection, a new target of HOTAIR was identified. Additionally, Western blotting and RIP analysis were adopted to discuss the possible mechanism.

Results

HOTAIR expression in CSCC cell lines exhibited an obvious elevation. Cell function analysis revealed that HOTAIR overexpression remarkably facilitated CSCC cell migration, proliferation and EMT process, which were impeded by down-regulation of HOTAIR. Furthermore, HOTAIR competitively bound to miR-326, so as to positively modulate miR-326 expression.

Conclusions

These results present that HOTAIR, as a ceRNA, regulates PRAF2 expression by competitive binding to miR-326 during CSCC.

PRAF2 overexpression predicts poor prognosis and promotes tumorigenesis in esophageal squamous cell carcinoma

BACKGROUND

Prenylated Rab acceptor 1 domain family, member 2 (PRAF2) is involved in the occurrence and progression of several malignant tumors. However, its potential role in esophageal squamous cell carcinoma (ESCC) is still unknown.

METHODS

PRAF2 mRNA expression was determined in 77 frozen ESCC samples by quantitative reverse transcription-polymerase chain reaction (qPCR) and its association with clinical features and overall survival were evaluated. The roles of PRAF2 in ESCC cells were investigated by proliferation, cell cycle, invasion and apoptosis assays in vitro.

RESULTS

The PRAF2 mRNA expression was significantly increased in ESCC tissues compared with matched surrounding non-tumor tissues. Survival analysis showed that high PRAF2 mRNA expression was associated with worse overall survival in ESCC patients. Multivariate analysis revealed that PRAF2 (hazard ratio 2.05, 95% CI 1.10-3.85, P = 0.025) emerged as the independent predictor for poor overall survival in ESCC. The in vitro experiments revealed that knockdown of PRAF2 expression blocked cell proliferation, cell cycle progression and cell invasion and induced cell apoptosis in ESCC cells.

CONCLUSION

Taken together, our data demonstrate that PRAF2 could be used as a potential prognostic biomarker and represent a potential therapeutic target for ESCC.

Mutual regulation of JAG2 and PRAF2 promotes migration and invasion of colorectal cancer cells uncoupled from epithelial-mesenchymal transition

Background

Our previous studies revealed that Jagged 2 (JAG2) is involved in the regulation of migration and invasion of colon cancer cells without affecting cell proliferation. This study further explored the specific mechanism by which JAG2 promotes migration and invasion of colorectal cancer cells.

Methods

JAG2 mRNA expression in different clinical stages of colorectal cancer and normal intestinal tissues was detected by quantitative PCR (QPCR). QPCR and Western Blot were used to analyze the differential expression of JAG2 mRNA and protein between normal human colon tissue cells and various colorectal cancer cells. Co-expression status of JAG2 and epithelial–mesenchymal transition (EMT) markers in colon cancer tissues and cells was analyzed. The difference between TGF-β-induced EMT model and the JAG2 overexpression model were compared in promoting migration and invasion of HT29 cells. HT29 cells were treated with EMT pathway inhibitors (LY2157299 and Slug siRNA) to identify a cross-talk between the JAG2 effect and the Notch pathway. Co-expressed genes of JAG2 in colorectal cancer cells were identified using siRNA and transcriptome microarray technology. The mutual regulation of JAG2 and the co-expressed gene PRAF2 and the regulation of the paracrine effect of exosomes were analyzed.

Results

JAG2 was abnormally expressed in colorectal cancer tissues and directly related to clinical stages. Similar to the findings in tissues, the expression of both JAG2 mRNA and protein was significantly increased in the colorectal cancer cell lines compared with that of normal colorectal cell line CCD18-Co. It was shown in our cell model that JAG2 was involved in the regulation of migration and invasion independent of the canonical Notch signaling pathway. More interestingly, JAG2 also promoted the migration and invasion of colon cancer cells in a non-EMT pathway. Further analysis revealed the co-expression of JAG2 with PRAF2 in colorectal cancer cells. JAG2-rich exosomes were released from colorectal cancer cells in a PRAF2-dependent way, while these exosomes regulated the metastasis of colorectal cancer cells in a paracrine manner.

Conclusions

This is the evidence supporting the biological function of JAG2 through non-canonical Notch and non-EMT-dependent pathways and also the first demonstration of the functions of PRAF2 in colorectal cancer cells. These findings also provide theoretical basis for the development of small molecules or biological agents for therapeutic intervention targeting JAG2/PRAF2.

Electronic supplementary material

The online version of this article (10.1186/s12935-019-0871-5) contains supplementary material, which is available to authorized users.