Effect of RAB31 silencing on osteosarcoma cell proliferation and migration through the Hedgehog signaling pathway

LncRNA HOXA10-AS Activated by E2F1 Facilitates Proliferation and Migration of Nasopharyngeal Carcinoma Cells Through Sponging miR-582-3p to Upregulate RAB31

Nasopharyngeal carcinoma (NPC) is a kind of head and neck cancer with a characteristic regional distribution. Increasing evidence has illustrated that long noncoding RNAs (lncRNAs) exert the regulatory function in tumor development. Nevertheless, the specific functions of lncRNA HOXA10 antisense RNA (HOXA10-AS) in NPC remain to be clarified. In this research, quantitative reverse transcription polymerase chain reaction detected HOXA10-AS expression in NPC cells. Cell counting kit-8, colony formation, and transwell assays were utilized to measure the proliferation and migration of NPC cells. Moreover, mechanism assays detected the interaction of different genes. Briefly, HOXA10-AS was highly expressed in NPC cells. HOXA10-AS down-regulation restrained NPC cell proliferation and migration. Further, HOXA10-AS could bind to miR-582-3p by acting as a competing endogenous RNA. Besides, Ras-related protein Rab-31 (RAB31) was proven as the target gene of miR-582-3p. Additionally, E2F transcription factor 1 (E2F1) acted as a transcription factor to activate HOXA10-AS expression. In the final rescue assays, we observed that the effect of HOXA10-AS depletion on NPC cell growth could be fully reversed by RAB31 overexpression or miR-582-3p inhibition. In short, our research proved that HOXA10-AS activated by E2F1 facilitated proliferation and migration of NPC cells through sponging miR-582-3p to upregulate RAB31.

Rab31 promotes the invasion and metastasis of cervical cancer cells by inhibiting MAPK6 degradation

Persistent infection with high-risk human papillomavirus (HPV) is the main risk factor for cervical cancer. Our mass spectrometry data showed that the Ras-associated binding protein Rab31 was upregulated by HPV; however, little is known regarding the role of Rab31 in the metastasis of cervical cancer cells. In this study, we showed that Rab31 was highly expressed in cervical cancer tissues and cells, and both HPV E6 and E7 promoted the expression of Rab31. Rab31 knockdown inhibited while Rab31 overexpression promoted the migration and invasion capabilities of cervical cancer cells. Additionally, Rab31 knockdown inhibited the epithelial-mesenchymal transition (EMT) and cytoskeletal rearrangement in cervical cancer cells. Furthermore, Rab31 interacted with mitogen-activated protein kinase 6 (MAPK6), and Rab31 knockdown inhibited the expression of MAPK6, which was mainly localized in the cytoplasm. More importantly, Rab31 knockdown promoted and Rab31 overexpression inhibited MAPK6 degradation. Accordingly, MAPK6 overexpression restored the decreased migration potential caused by Rab31 knockdown. Finally, a xenograft mouse model showed that Rab31 knockdown in cervical cancer cells led to reduced tumor growth and impaired lung and liver metastasis in vivo. In conclusion, Rab31 plays a crucial role in cervical cancer metastasis by inhibiting MAPK6 degradation. Thus, Rab31 may serve as a novel therapeutic target to manage cervical cancer.

Rab31-dependent regulation of transforming growth factor ß expression in breast cancer cells

BACKGROUND

The small GTP-binding protein Rab31 plays an important role in the modulation of tumor biological-relevant processes, including cell proliferation, adhesion, and invasion. As an underlying mechanism, Rab31 is presumed to act as a molecular switch between a more proliferative and an invasive phenotype. This prompted us to analyze whether Rab31 overexpression in breast cancer cells affects expression of genes involved in epithelial-to-mesenchymal transition (EMT)-like processes when compared to Rab31 low-expressing cells.

METHODS

Commercially available profiler PCR arrays were applied to search for differentially expressed genes in Rab31 high- and low-expressing CAMA-1 breast cancer cells. Differential expression of selected candidate genes in response to Rab31 overexpression in CAMA-1 cells was validated by independent qPCR and protein assays.

RESULTS

Gene expression profiling of key genes involved in EMT, or its reciprocal process MET, identified 9 genes being significantly up- or down-regulated in Rab31 overexpressing CAMA-1 cells, with the strongest effects seen for TGFB1, encoding TGF-ß1 (> 25-fold down-regulation in Rab31 overexpressing cells). Subsequent validation analyses by qPCR revealed a strong down-regulation of TGFB1 mRNA levels in response to increased Rab31 expression not only in CAMA-1 cells, but also in another breast cancer cell line, MDA-MB-231. Using ELISA and Western blot analysis, a considerable reduction of both intracellular and secreted TGF-ß1 antigen levels was determined in Rab31 overexpressing cells compared to vector control cells. Furthermore, reduced TGF-ß activity was observed upon Rab31 overexpression in CAMA-1 cells using a sensitive TGF-ß bioassay. Finally, the relationship between Rab31 expression and the TGF-ß axis was analyzed by another profiler PCR array focusing on genes involved in TGF-ß signaling. We found 12 out of 84 mRNAs significantly reduced and 7 mRNAs significantly increased upon Rab31 overexpression.

CONCLUSIONS

Our results demonstrate that Rab31 is a potent modulator of the expression of TGF-ß and other components of the TGF-ß signaling pathway in breast cancer cells.

GANT61 plays antitumor effects by inducing oxidative stress through the miRNA-1286/RAB31 axis in osteosarcoma

Osteosarcoma (OS) is a rare malignancy of bone associated with poor clinical outcomes. The antitumor effects of GANT61 on OS is unclear. To investigate antitumor effects and mechanism of GANT61 in OS cells and xenograft model. Effects of GANT61 on cell viability, clone formation, cell cycle, apoptosis, migration, and invasion ability of OS cells were assessed. Reactive oxygen species (ROS) levels measured by dichlorofluorescein fluorescence were used to evaluate oxidative stress. The Xenograft model was constructed to investigate the antitumor effects of GANT61 in vivo. The microRNA (miRNA)-1286 was downregulated, while RAB31 upregulated in OS tissues and cells. GANT61 inhibited viability, migration, and invasion ability of OS cells (SaOS-2 and U2OS), and induced apoptosis and the ROS production, along with miRNA-1286 upregulation and RAB13 downregulation. After knockdown of miRNA-1286, GANT6-induced cell inhibition was attenuated, along with RAB31 upregulation. Inversely, miRNA-1286 overexpression downregulated RAB31. Dual-luciferase reporter assay verified that miR-1286 negatively targeted RAB13. Moreover, the knockdown of RAB31 stimulated apoptosis and ROS production while inhibited viability, migration, and invasion of GANT61-treated cells. In vivo experiments further confirmed that GANT61 inhibited tumor growth and RAB13 expression, but enhanced miRNA-1286. The study demonstrated that GANT61 inhibited cell aggressive phenotype and tumor growth by inducing oxidative stress through the miRNA-1286/RAB31 axis. Our findings provided a potential antitumor agent for the OS clinical treatment.

CircZNF609 enhances hepatocellular carcinoma cell proliferation, metastasis, and stemness by activating the Hedgehog pathway through the regulation of miR-15a-5p/15b-5p and GLI2 expressions

Emerging evidence has revealed that aberrantly expressed circular RNAs (circRNAs) play vital roles in tumorigenesis and progression of diverse human malignancies. Although an existing literature has elucidated the regulatory role of circZNF609 in breast cancer, the crucial function that circZNF609 exerted on hepatocellular carcinoma (HCC) remains unclear. Herein, we determined to explore the molecular mechanism of circZNF609 in HCC. In this study, circZNF609 was conspicuously overexpressed and featured with loop structure in HCC. Functional tests revealed that decreased expression of circZNF609 suppressed cell proliferation, metastasis and stemness, whereas induced cell apoptosis in HCC. Subsequent molecular mechanism assays indicated that circZNF609 contributed to HCC progression through activation of Hedgehog pathway. Moreover, circZNF609 was found to be negatively correlated with miR-15a-5p/15b-5p but positively correlated with GLI2. Moreover, there was a negative correlation between miR-15a-5p/15b-5p and GLI2. Rescue experiments testified that GLI2 overexpression could recover circZNF609 depletion-mediated function on HCC development while miR-15a-5p/15b-5p inhibition could partially rescue circZNF609 silencing-mediated effect on HCC progression. Final experiments in vivo further elucidated the suppressive function of circZNF609 knockdown on the tumorigenesis of HCC. Briefly, circZNF609 enhances HCC cell proliferation, metastasis, and stemness by activating the Hedgehog pathway through the regulation of miR-15a-5p/15b-5p and GLI2 expressions.

NR2F1-induced NR2F1-AS1 promotes esophageal squamous cell carcinoma progression via activating Hedgehog signaling pathway

Emerging evidence has uncovered the extremely important roles of long noncoding RNAs (lncRNAs) in the progression of malignant tumors which includes numerous processes of gene regulation. LncRNA NR2F1-AS1 has been confirmed to have close correlation with the tumorigenesis of diverse cancers. However, the underlying regulatory function of it on esophageal squamous cell carcinoma (ESCC) progression is poorly known and thus needs more elucidations. In this study, a markedly elevated expression of NR2F1-AS1 was discovered in ESCC cells. Functional assays demonstrated that NR2F1-AS1 deficiency repressed ESCC progression. Molecular mechanism tests verified that knockdown of NR2F1-AS1 could lower the expression of GLI2 (a key protein molecule of Hedgehog signaling pathway) in ESCC. Additionally, NR2F1-AS1 was confirmed to facilitate ESCC progression via activation of Hedgehog signaling pathway. NR2F1-AS1 activated Hedgehog signaling pathway by regulating GLI2 to upregulate NR2F1 expression in ESCC. Besides, NR2F1 was testified to activate NR2F1-AS1 transcription in ESCC. Final rescue assays further demonstrated that NR2F1 upregulation could reverse the NR2F1-AS1 knockdown-mediated function on ESCC progression. Briefly, NR2F1-induced NR2F1-AS1 promotes ESCC progression through activation of Hedgehog signaling pathway.