Inhibition of RAB1A suppresses epithelial-mesenchymal transition and proliferation of triple-negative breast cancer cells

Emerging roles of circular RNAs in the invasion and metastasis of head and neck cancer: Possible functions and mechanisms

Head and neck cancer (HNC) is the seventh most prevalent malignancy worldwide in 2020. Cancer metastasis is the main cause of poor prognosis in HNC patients. Recently, circular RNAs (circRNAs), initially thought to have no biological function, are attracting increasing attention, and their crucial roles in mediating HNC metastasis are being extensively investigated. Existing studies have shown that circRNAs primarily function through miRNA sponges, transcriptional regulation, interacting with RNA-binding proteins (RBPs) and as translation templates. Among these functions, the function of miRNA sponge is the most prominent. In this review, we summarized the reported circRNAs involved in HNC metastasis, aiming to elucidate the regulatory relationship between circRNAs and HNC metastasis. Furthermore, we summarized the latest advances in the epidemiological information of HNC metastasis and the tumor metastasis theories, the biogenesis, characterization and functional mechanisms of circRNAs, and their potential clinical applications. Although the research on circRNAs is still in its infancy, circRNAs are expected to serve as prognostic markers and effective therapeutic targets to inhibit HNC metastasis and significantly improve the prognosis of HNC patients.

CD83+ B cells alleviate uveitis through inhibiting DCs by sCD83

Soluble CD83 (sCD83) exerts immunosuppressive functions in many autoimmune diseases, including experimental autoimmune uveitis (EAU), but the cells and mechanisms involved are unclear. This study showed that CD83+ B cells were the main sources of sCD83. They alleviated the symptoms of EAU and decreased the percentage of T cells and DCs in the eyes and lymph nodes. These CD83+ B cells decreased IL-1β, IL-18 and IFN-γ secretion by DCs through sCD83. sCD83 interacted with GTPase Ras-related protein (Rab1a) in DCs to promote Rab1a accumulation in autolysosomes and inhibit mTORC1 phosphorylation and NLRP3 expression. Hence, CD83+ B cells play a regulatory role in EAU by secreting sCD83. The lack of regulation of CD83+ B cells might be an important factor leading to hyperimmune activation in patients with autoimmune uveitis. CD83+ B cells suppress activated DCs in uveitis, indicating the potential therapeutic role of CD83+ B cells in uveitis.

Prognosis value and positive association of Rab1A/IL4Rα aberrant expression in gastric cancer

Gastric cancer (GC) is the most common gastrointestinal cancer and the leading cause of worldwide cancer-associated mortality. Several GC patients are diagnosed at the advanced stage with an unsatisfactory 5-year survival rate. Rab1A was significantly associated with IL4Rα expression in non-small cell lung cancer. However, their potential correlation in expression and prognosis remains largely unknown in GC. In this study, Rab1A/IL-4Rα was significantly increased in GC than in para-cancerous tissues, and Rab1A/IL-4Rα overexpression caused poor prognosis among GC patients. Rab1A expression was significantly correlated with IL-4Rα expression in GC tissues, as determined by IHC analysis. In addition, the mRNA expression of Rab1A was closely linked with the IL-4Rα mRNA expression in GC tissue expressed by qPCR. Furthermore, the Kaplan-Meier analysis demonstrated that the group with negative Rab1A and IL-4Rα expression had longer 5-year survival rates than the other group. Besides, the group with positive Rab1A and IL-4Rα expression had a worse prognosis than the other group. Finally, nomograms revealed the overall 3 and 5-year survival determined crucial roles of Rab1A/IL-4Rα expression in predicting the prognosis of GC patients. Therefore, Rab1A/IL-4Rα is vital in GC, providing a novel perspective on targeted GC therapy.

GOLPH3 protein controls organ growth by interacting with TOR signaling proteins in Drosophila

The oncoprotein GOLPH3 (Golgi phosphoprotein 3) is an evolutionarily conserved phosphatidylinositol 4-phosphate effector, mainly localized to the Golgi apparatus, where it supports organelle architecture and vesicular trafficking. Overexpression of human GOLPH3 correlates with poor prognosis in several cancer types and is associated with enhanced signaling downstream of mTOR (mechanistic target of rapamycin). However, the molecular link between GOLPH3 and mTOR remains elusive. Studies in Drosophila melanogaster have shown that Translationally controlled tumor protein (Tctp) and 14-3-3 proteins are required for organ growth by supporting the function of the small GTPase Ras homolog enriched in the brain (Rheb) during mTORC1 (mTOR complex 1) signaling. Here we demonstrate that Drosophila GOLPH3 (dGOLPH3) physically interacts with Tctp and 14-3-3ζ. RNAi-mediated knockdown of dGOLPH3 reduces wing and eye size and enhances the phenotypes of Tctp RNAi. This phenotype is partially rescued by overexpression of Tctp, 14-3-3ζ, or Rheb. We also show that the Golgi localization of Rheb in Drosophila cells depends on dGOLPH3. Consistent with dGOLPH3 involvement in Rheb-mediated mTORC1 activation, depletion of dGOLPH3 also reduces levels of phosphorylated ribosomal S6 kinase, a downstream target of mTORC1. Finally, the autophagy flux and the expression of autophagic transcription factors of the TFEB family, which anti correlates with mTOR signaling, are compromised upon reduction of dGOLPH3. Overall, our data provide the first in vivo demonstration that GOLPH3 regulates organ growth by directly associating with mTOR signaling proteins.

Targeted disruption of Rab1a causes early embryonic lethality

Guanosine nucleotide diphosphate (GDP) dissociation inhibitor 2 (GDI2) regulates the GDP/guanosine triphosphate (GTP) exchange reaction of Rab proteins by inhibiting the dissociation of GDP and the subsequent binding of GTP. The present study aimed to determine the function of Rab1a in vivo, and thus generated mice with a trapped Rab1a gene. It was demonstrated that Rab1a is essential for embryonic development. It was also found that one functional Rab1a allele was sufficient for development in a heterozygous murine embryo, whereas a double mutant led to embryonic lethality. The dissection of uteri on embryonic day (E)10.5‑14.5 yielded no homozygous embryos, indicating that homozygotes die between E10.5 to E11.5. The gene trap construct contains a β‑galactosidase/neomycin reporter gene, allowing for heterozygotes to be stained for β‑galactosidase to determine the tissue‑specific expression of Rab1a. Rab1a was found to be highly expressed in the small intestine of both adult mice and embryos, although its expression levels were low in the brains of embryos. Moreover, there was no significant change in cytokine production and survival in wild‑type and heterozygous Rab1a+/‑ mice following a challenge with lipopolysaccharide. On the whole, the present study demonstrates that the disruption of the Rab1a gene causes embryonic lethality and homozygotes die between E10.5 and E11.5, suggesting that Rab1a is essential for the early development of mouse embryos.

Rab1A promotes cell proliferation and migration by upregulating Gli1 in colorectal cancer

Rab1A, as a highly conserved small guanosine triphosphatase (GTPase), plays contentious roles in different types of cancers. The role of Rab1A in colorectal cancer (CRC) has been described in previous studies, but the molecular mechanisms of Rab1A in CRC remain far from being addressed. In the present study, we found that Rab1A expression was significantly upregulated in CRC tissues and increased Rab1A expression correlated with tumor size, lymph node metastasis (LNM) and tumor-node-metastasis (TNM) stage of CRC patients. We also found that Rab1A exerts its promotive effect on CRC cell proliferation, migration and EMT progress. Further mechanistic experiments showed that glioma-associated oncogene-1 (Gli1), as a key transcriptional factor of the Hedgehog pathway, was implicated in Rab1A-mediated regulation of CRC cell proliferation and migration. In addition, Rab1A upregulated Gli1 expression through Smoothened homolog (SMO)-independent pathway. Finally, Rab1A activated mechanistic target of rapamycin (mTOR) signaling in CRC cells. Collectively, our results define Rab1A as a novel regulator of Gli1 to promote CRC cell proliferation and migration, and suggest that the Rab1A/mTOR/Gli1 axis may serve as a promising therapeutic target for the treatment of CRC.

Proteomic Characterization of Cytoplasmic Lipid Droplets in Human Metastatic Breast Cancer Cells

One of the characteristic features of metastatic breast cancer is increased cellular storage of neutral lipid in cytoplasmic lipid droplets (CLDs). CLD accumulation is associated with increased cancer aggressiveness, suggesting CLDs contribute to metastasis. However, how CLDs contribute to metastasis is not clear. CLDs are composed of a neutral lipid core, a phospholipid monolayer, and associated proteins. Proteins that associate with CLDs regulate both cellular and CLD metabolism; however, the proteome of CLDs in metastatic breast cancer and how these proteins may contribute to breast cancer progression is unknown. Therefore, the purpose of this study was to identify the proteome and assess the characteristics of CLDs in the MCF10CA1a human metastatic breast cancer cell line. Utilizing shotgun proteomics, we identified over 1500 proteins involved in a variety of cellular processes in the isolated CLD fraction. Interestingly, unlike other cell lines such as adipocytes or enterocytes, the most enriched protein categories were involved in cellular processes outside of lipid metabolism. For example, cell-cell adhesion was the most enriched category of proteins identified, and many of these proteins have been implicated in breast cancer metastasis. In addition, we characterized CLD size and area in MCF10CA1a cells using transmission electron microscopy. Our results provide a hypothesis-generating list of potential players in breast cancer progression and offers a new perspective on the role of CLDs in cancer.

RAB1A regulates glioma cellular proliferation and invasion via the mTOR signaling pathway and epithelial-mesenchymal transition

Aim: We aimed at investigating the mechanism of RAB1A proliferation and invasion in gliomas. Materials & methods: Genome-wide expression profile data and immunohistochemistry were analyzed to assess RAB1A expression in gliomas. The Transwell assay, wound healing assay, brain slice coculture model, cellular fluorescence and intracranial xenograft model of nude mice were used to determine the proliferation and invasion of glioma cells. Results & conclusion: RAB1A was highly expressed in gliomas compared with normal brain tissue. The overall survival time of glioma patients with high RAB1A expression was significantly shortened. RAB1A regulated the activity of RAC1 by inhibiting the mTOR signaling pathway, affecting actin polymerization, cell morphology and cell polarity. RAB1A downregulation inhibited the epithelial-mesenchymal transition, proliferation and invasion of glioma cells.

Clinical value and potential association of Rab1A and FoxM1 aberrant expression in colorectal cancer

Colorectal carcinoma (CRC) is one of the most common malignancies with a dismal 5-year survival rate. Our recent study indicated that Rab1A expression was closely related to GLI1 expression. A previous study shows that aberrant overexpression of GLI1 promotes colorectal cancer metastasis via FoxM1 overexpression. However, the potential correlation between Rab1A and FoxM1 in CRC remains elusive. Immunohistochemistry was performed to investigate the association of the expression of Rab1A and FoxM1 and to determine the prognosis in 135 CRC tissue and adjacent normal tissues. Using Oncomine datasets, we found that Rab1A and FoxM1 mRNA were obviously upregulated in CRC tissues compared to normal tissues. Additionally, the expression of Rab1A and FoxM1 was significantly higher in CRC tissues than that in normal tissues. Rab1A expression was positively correlated with FoxM1 expression in CRC, especially in TNM stage III. In addition, Rab1A and FoxM1 overexpression was found to be significantly correlated with poor prognosis in CRC patients. Besides, both high expression of Rab1A and FoxM1 led to a worse prognosis than anyone low group, and both low expression of Rab1A and FoxM1 had a better prognosis than the anyone low group. Therefore, Rab1A and FoxM1 play crucial roles and could be used as clinical biomarkers in CRC.

Rab1A promotes cancer metastasis and radioresistance through activating GSK-3β/Wnt/β-catenin signaling in nasopharyngeal carcinoma

Many articles have reported that Rab1A was overexpressed in a variety of human cancers and involved in tumor progression and metastasis. However, the biological function and molecular mechanism of Rab1A in nasopharyngeal carcinoma (NPC) remained unknown until now. Here we found that Rab1A overexpression is a common event and was positively associated with distant metastasis and poor prognosis of NPC patients. Functionally, Rab1A depletion inhibited the migration and EMT phenotype of NPC cells, whereas Rab1A overexpression led to the opposite effect. Furthermore, we reveal an important role for Rab1A protein in the induction of radioresistance via regulating homologous recombination (HR) signaling pathway. Mechanistically, Rab1A activated Wnt/β-catenin signaling by inhibiting the activity of GSK-3β via phosphorylation at Ser9. Then Wnt/β-catenin signaling induced NPC cells radioresistance and metastasis through nuclear translocation of β-catenin and transcription upregulation of HR pathway-related and EMT-related genes expression. In general, this study shows that Rab1A may serve as a potential biomarker for predicting prognosis in NPC patients. Targeting Rab1A and Wnt/β-catenin signaling may hold promise to overcome NPC radioresistance.

CircRNA circUGGT2 Contributes to Hepatocellular Carcinoma Development via Regulation of the miR-526b-5p/RAB1A Axis

Background

Hepatocellular carcinoma (HCC) is a common malignant tumor in the world. Circular RNA hsa_circ_0008274 (circUGGT2) is reported to be upregulated in HCC tissues. Notwithstanding, the role and regulatory mechanism of circUGGT2 in HCC are indistinct.

Methods

Quantitative real-time polymerase chain reaction (qRT-PCR) was implemented to examine the levels of circUGGT2, microRNA (miR)-526b-5p, and ras-related protein Rab-1A (RAB1A) mRNA in HCC tissues and cells. Cell proliferation and colony formation were assessed with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide (MTT) or colony formation assays. The levels of cyclin D1, proliferating cell nuclear antigen (PCNA), and RAB1A were detected with Western blotting. Cell cycle progression, migration, and invasion were evaluated by using flow cytometry or transwell assays. The relationship between circUGGT2 or RAB1A and miR-526b-5p was verified via dual-luciferase reporter and/or RNA pull-down assays. Xenograft assay was executed to confirm the role of circUGGT2 in vivo.

Results

We observed that circUGGT2 and RAB1A were upregulated while miR-526b-5p was downregulated in HCC tissues and cells. CircUGGT2 silencing suppressed tumor growth in vivo and curbed proliferation, colony formation, cell cycle progression, migration, and invasion of HCC cells in vitro. Mechanically, circUGGT2 regulated RAB1A expression via competitively binding to miR-526b-5p. Also, the inhibitory influence of circUGGT2 silencing on the malignancy of HCC cells was overturned by miR-526b-5p inhibitor. Furthermore, RAB1A overexpression reversed the suppressive influence of miR-526b-5p mimic on the malignancy of HCC cells.

Conclusion

CircUGGT2 silencing inhibited HCC development via modulating the miR-526b-5p/RAB1A axis, providing a possible target for HCC treatment.

USP6NL mediated by LINC00689/miR-142-3p promotes the development of triple-negative breast cancer

Background

Triple-negative breast cancer (TNBC), in part because of the high metastasis rate, is one of the most prevalent causes of malignancy-related mortality globally. Ubiquitin specific peptidase 6 N-terminal like (USP6NL) has been unmasked to be implicated in some human cancers. However, the precise biological function of USP6NL in TNBC has not been defined.

Methods

RNA expression was examined by real-time quantitative PCR (RT-qPCR), while USP6NL protein level was tested through western blot. Besides, cell proliferation was assessed by using colony formation assay, whereas cell apoptosis estimated by flow cytometry analysis, JC-1 assay and TUNEL assay. Transwell assays were adopted to detect the migration and invasion of indicated TNBC cells. Immunofluorescence (IF) assay evaluated epithelial-mesenchymal transitions (EMT) progress in TNBC. Further, RNA immunoprecipitation (RIP), RNA pull down and luciferase reporter assays were implemented for measuring the mutual interplay among USP6NL, miR-142-3p and long intergenic non-protein coding RNA 689 (LINC00689).

Results

Elevated USP6NL level was uncovered in TNBC cells. RNA interference-mediated knockdown of USP6NL inhibited TNBC cell growth, motility and EMT. Further, USP6NL was proved as the target of a tumor-inhibitor miR-142-3p, and LINC00689 augmented USP6NL expression by absorbing miR-142-3p. Importantly, miR-142-3p deficiency or USP6NL overexpression fully abolished the inhibitory effect of LINC00689 silence on TNBC cellular behaviors.

Conclusion

All data revealed the important role of USP6NL/LINC00689/miR-142-3p signaling in TNBC. The findings might provide a new and promising therapeutic biomarker for treating patients with TNBC.

Expression of Rab1A in bladder cancer and its clinical implications

Rab1A protein has been identified to be highly expressed in a number of malignant tumor tissues and to participate in the regulation of tumor development, but no data concerning bladder cancer have been described at present. The present study measured the expression of Rab1A in bladder cancer tissues and cell lines, and analyzed its clinical significance for patients with bladder cancer. A total of 153 pairs of bladder cancer tumor tissues and adjacent cancer healthy tissues were included in the present study. Western blot analysis and immunohistochemistry were used to measure the expression of Rab1A protein in normal bladder and bladder cancer cell line, and bladder cancer and normal adjacent tissues. SPSS 20.0 software was used for statistical analysis and mapping of survival curves in patients with bladder cancer. The expression levels of Rab1A protein in normal bladder cells and tissues was significantly decreased compared with that in bladder cancer cells and tissues, and it was significantly associated with tumor size, histological grade, tumor-node-metastasis (TNM) stage, lymph node metastasis and remote metastasis in 153 patients with bladder cancer. Cox regression analysis demonstrated that the expression of Rab1A protein in bladder cancer tissues was an independent risk factor for prognosis (overall risk=0.549; 95% confidence interval=0.139-0.916). The 5-year survival rate of patients with bladder cancer with high expression levels of Rab1A protein was 48.613%, which was significantly decreased compared with the rate of patients with low expression 75.31% (P<0.05). The expression of Rab1A in bladder cancer tissues and cell lines was upregulated, and its expression increased with increasing TNM stages. It was also associated with the metastasis of tumor cells and negatively affected the survival time of patients with bladder cancer.

[Effects of RAB1A on the proliferation, invasion, and metastasis of tongue squamous cell carcinoma cells]

OBJECTIVE

This study aimed to investigate the molecular mechanism of RAB1A in the proliferation, invasion, and metastasis of human tongue squamous cell carcinoma.

METHODS

Western blot was used to detect the expression of RAB1A protein in human normal tongue epithelial cells (Hacat) and tongue squamous cell carcinoma Tca8113. The changes in RAB1A after plasmid transfection were also studied. The Tca8113 cells were named SiRAB1A/Tca8113 after RAB1A plasmid transfection. The expression of the epithelial-mesenchymal transition (EMT)-related markers of SiRAB1A/Tca8113 cells was also detected. CCK-8 assay was used to detect the proliferation of SiRAB1A/Tca8113 cells. Transwell and wound healing assays were used to detect the invasive and metastatic abilities of SiRAB1A/Tca8113 cells, respectively.

RESULTS

Western blot results showed that the expression of RAB1A in tongue squamous cell carcinoma cells was significantly higher than that in Hacat. RAB1A decreased significantly after SiRAB1A plasmid transfection. CCK-8 proliferation assay showed that the proliferation of SiRAB1A/Tca8113 cells also decreased significantly. Transwell and wound healing assays demonstrated that the invasive and metastatic abilities of SiRAB1A/Tca8113 cells decreased significantly, respectively. In addition, Western blot results demonstrated that RAB1A deletion significantly increased the expression of E-cadherin and inhibited the expression of Vimentin.

CONCLUSIONS

RAB1A could promote the proliferation, invasion, and metastasis of tongue squamous cell carcinoma cells.

Antitumor potential of dark sweet cherry sweet (Prunus avium) phenolics in suppressing xenograft tumor growth of MDA-MB-453 breast cancer cells

This study investigated in vivo the antitumor activity of dark sweet cherry (DSC) whole extracted phenolics (WE) and fractions enriched in anthocyanins (ACN) or proanthocyanidins (PCA) in athymic mice xenografted with MDA-MB-453 breast cancer cells. Mice were gavaged with WE, ACN or PCA extracts (150 mg/kg body weight/day) for 36 days. Results showed that tumor growth was suppressed at similar levels by WE, ACN and PCA compared to control group (C) without signs of toxicity or significant changes in mRNA oncogenic biomarkers in tumors or mRNA invasive biomarker in distant organs. Tumor protein analyses showed that WE, ACN and PCA induced at similar levels the stress-regulated ERK1/2 phosphorylation, known to be linked to apoptosis induction. However, ACN showed enhanced antitumor activity through down-regulation of total oncogenic and stress-related Akt, STAT3, p38, JNK and NF-kB proteins. In addition, immunohistochemistry analysis of Ki-67 revealed inhibition of tumor cell proliferation with potency WE ≥ ACN ≥ PCA. Differential quantitative proteomic high-resolution nano-HPLC tandem mass spectrometry analysis of tumors from ACN and C groups revealed the identity of 66 proteins associated with poor breast cancer prognosis that were expressed only in C group (61 proteins) or differentially up-regulated (P<.05) in C group (5 proteins). These findings revealed ACN-targeted proteins associated to tumor growth and invasion and the potential of DSC ACN for breast cancer treatment. Results lead to a follow-up study with highly immunodeficient mice/invasive cell line subtype and advanced tumor development to validate the anti-invasive activity of DSC anthocyanins.

Prognosis, Significance and Positive Correlation of Rab1A and p-S6K/Gli1 Expression in Gastric Cancer

BACKGROUND

Gastric Cancer (GC) is a frequently common malignancy. Recent studies have reported Rab1A as an activator of mTORC1, and the mTOR1 pathway is involved in regulating Gli1 expression in several cancers. Only a few studies have been performed to explore the relationship between Rab1A and p-S6K/Gli1in GC.

METHODS

Immunohistochemistry (IHC) was performed to explore the association of Rab1A/p-S6K/Gli1 expression and prognosis in 117 GC tissue samples and adjacent normal tissues.

RESULTS

Our results indicated that Rab1A/p-S6K/Gli1 was significantly overexpressed in GC tissues. High expression of Rab1A was closely related to the tumor size and the depth of tumor invasion. In addition, Rab1A expression was closely related with p-S6K/Gli1 expression in GC, and high level of Rab1A/p-S6K/Gli1 caused worse prognosis of GC patients. The univariate and multivariate analysis indicated that the expression of Rab1A was an independent prognostic factor. Moreover, both high Rab1A and p-S6K expression led to a worse prognosis when compared to a single positive expression as well as both high Rab1A/Gli1 expression also led to a worse prognosis than the single positive expression of Rab1A/Gli1. Strikingly, the overexpression of p-S6K also led to a worse prognosis in Rab1A positive patients, as did Gli1.

CONCLUSION

Our results indicate that Rab1A/mTOR/S6K/Gli1 axis played a crucial role in GC, which may provide a novel field on targeted therapy of GC, especially for mTORC1-targeted therapy-resistant cancers.

Rab1A knockdown represses proliferation and promotes apoptosis in gastric cancer cells by inhibition of mTOR/p70S6K pathway

Rab1A, a member of the Ras-like protein in rat brain (Rab) family, acts as an oncogene in a variety of malignant tumors. Previous studies reported that Rab1A was highly expressed in GC tissues. However, the function and molecular mechanism of Rab1A in gastric cancer (GC) development remain far from being addressed. Rab1A mRNA and protein levels were detected by qRT-PCR and western blot, respectively. Cell proliferation was evaluated by CCK-8 and BrdU incorporation assays. Apoptosis was estimated by flow cytometry analysis and western blot analysis of B cell lymphoma 2 (Bcl-2), myeloid cell leukemia 1 (Mcl-1), Bcl-2 associated X (Bax), and Bcl-2 homologous antagonist/killer (Bak) expression. Alteration of the mammalian target of rapamycin (mTOR)/p70 ribosomal protein S6 kinase (p70S6K) signaling pathway was detected by western blot. We found that Rab1A expression at both mRNA and protein was upregulated in GC cells. Rab1A knockdown significantly inhibited cell proliferation and induced apoptosis in GC cells. Rab1A overexpression promoted proliferation, inhibited cisplatin-induced apoptosis, and increased xenograft growth. In addition, we found that Rab1A knockdown suppressed the mTOR/p70S6K pathway in GC cells. Moreover, activation of mTOR/p70S6K pathway by MHY1485 abolished the effects of Rab1A knockdown on cell proliferation and apoptosis. In conclusion, Rab1A knockdown repressed proliferation and promoted apoptosis in GC cells by inhibition of the mTOR/p70S6K pathway.

Circ_0000218 plays a carcinogenic role in colorectal cancer progression by regulating miR-139-3p/RAB1A axis

Accumulating researches have confirmed that circRNA abnormal expression plays a prominent role in the progression of colorectal cancer (CRC). The role of circ_0000218 in CRC and its potential mechanism are not clear. In this study, real-time polymerase chain reaction (RT-PCR) was employed to measure the circ_0000218, miR-139-3p and RAB1A mRNA expression in CRC tissues and cells. Immunohistochemistry and western blot were conducted to determine the RAB1A expression in CRC tissues and cells, respectively. Colony formation assay and BrdU method were employed to monitor the effect of circ_0000218 on cell proliferation. Transwell assay was adopted to detect cell migration and invasion. Dual luciferase reporter assay and RNA immunoprecipitation assay were adopted to confirm the targeting relationship between circ_0000218 and miR-139-3p, miR-139-3p and RAB1A. We demonstrated that circ_0000218 was notably upregulated in CRC tissues and cell lines, and its high expression level was markedly linked to the increase of T staging and local lymph node metastasis. Circ_0000218 overexpression enhanced the proliferation and metastasis of CRC cells while knocking down circ_0000218 caused the opposite effects. We also observed that miR-139-3p was negatively regulated by circ_0000218, while RAB1A was positively regulated by it. Collectively, this study suggested that circ_0000218 upregulated RAB1A and promoted CRC proliferation and metastasis via sponging miR-139-3p.

Long Noncoding RNA MNX1 antisense RNA 1 Exerts Oncogenic Functions in Bladder Cancer by Regulating miR-218-5p/RAB1A Axis

LncRNA MNX1 antisense RNA 1 (MNX1-AS1) is significantly overexpressed in patients with bladder cancer, suggesting that it might be associated with bladder cancer. However, the molecular mechanism of MNX1-AS1 in bladder cancer remained indistinct. To illustrate the role of MNX1-AS1 in bladder cancer, the gain- and loss-of-function experiments were conducted in bladder cancer cells. Reduced expression of MNX1-AS1 could suppress cell proliferation, migration, invasion, and epithelial-mesenchymal transition in bladder cancer cells, whereas overexpression of MNX1-AS1 resulted in the opposite effects. Mechanistic analysis demonstrated that miR-218-5p was a direct target of RAB1A. MNX1-AS1 could competitively bind to miR-218-5p to regulate RAB1A expression in bladder cancer cells. Furthermore, in vivo experiments revealed that reduced expression of MNX1-AS1 inhibited tumor growth and metastasis. Taken together, MNX1-AS1 functions as a sponge to miR-218-5p to modulate RAB1A expression in bladder cancer, which suggests that MNX1-AS1 might serve as a novel therapeutic target and a novel biomarker for metastasis and prognosis in bladder cancer. SIGNIFICANCE STATEMENT: Our study demonstrates that long noncoding RNA MNX1-AS1 promotes the initiation and progression of bladder cancer. MNX1-AS1 regulates RAB1A expression to promote proliferation, migration, invasion, and epithelial-mesenchymal transitions of bladder cancer cells via miR-218-5p, which contributes to the tumor growth and metastasis of bladder cancer. Collectively, these results suggest that MNX1-AS1 might serve as a potential biomarker for bladder cancer.

Pooled analysis of prognostic value and clinical significance of Rab1A expression in human solid tumors

BACKGROUND

This study aims to assess the relationship between Rab1A expression and clinicopathological parameters and prognosis of patients with human solid cancer by summarizing the studies included.

METHODS

PubMed, EMBASE, The Cochrane Library, and other sources were searched for relative studies. The risk ratios (RRs) and confidence interval (CI) were used to assess association between Rab1A expression and clinical parameters and prognosis in solid cancer patients.

RESULTS

Eight studies were included in the final analysis with 800 patients. The results revealed that expression of Rab1A was significantly related with differentiation (RR = 0.883, 95%CI = 0.782-0.997, P = .044), lymph node metastasis (RR = 0.835, 95%CI = 0.753-0.926, P = .001), tumor-lymph node-metastasis (TNM) stage (RR = 1.190, 95%CI = 1.071-1.322, P < .001) and tumor size (RR = 0.818, 95%CI = 0.730-0.915, P < .001). What is more, no significant difference was seen in 1-year survival between high and low expression of Rab1A in multiple malignancies (RR = 0.855, 95%CI = 0.697-1.050, P = .136). However, increased Rab1A revealed poorer prognosis with 2-year survival (RR = 0.760, 95%CI = 0.701-0.824, P < .001), 3-year survival (RR = 0.669, 95%CI = 0.604-0.742, P < .001), 4-year survival (RR = 0.622, 95%CI = 0.554-0.698, P < .001) and 5-year survival (RR = 0.525, 95%CI = 0.458-0.698, P < .001). Expression of Rab1A was increased obviously in solid cancer tissues compared with the adjacent normal tissue (RR = 4.78, 95%CI 4.05-5.63, P = .015).

CONCLUSION

This study revealed Rab1A expression links closely with tumor size, differentiation, lymph node metastasis, TNM stage and poor prognosis of human solid cancer patients. It may act as a biomarker of prognosis and a novel therapeutic target in solid cancer.

Elevated hsa-miR-590-3p expression down-regulates HMGB2 expression and contributes to the severity of IgA nephropathy

Peripheral blood mononuclear cells (PBMCs) play important roles in the pathogenesis of IgA nephropathy (IgAN). Our study aimed to provide a deep understanding of IgAN and focused on the dysregulation of hsa‐miR‐590‐3p and its target gene HMGB2 in PBMCs. Three gene expression profile datasets (GSE14795, GSE73953 and GSE25590) were downloaded from the GEO database. The DEGs (differentially expressed genes)‐miRNA network that was associated with IgAN was constructed by Cytoscape, and HMGB2 and hsa‐miR‐590‐3p were selected for further exploration. The dual‐luciferase reporter system was utilized to verify their interaction. Then, the expression levels of HMGB2 and hsa‐miR‐590‐3p in PBMCs were detected by qPCR in another cohort, and the correlation of their expression levels with the clinical pathological manifestations and serum Gd‐IgA1(galactose‐deficient IgA1) levels was also investigated. HMGB2 was identified as the target gene of hsa‐miR‐590‐3p. Furtherly, the elderly patients had higher HMGB2 expression levels than the expression levels of the younger patients. As the serum creatinine, serum BUN levels increased, the expression of HMGB2 decreased; Besides, the HMGB2 expression was positively correlated with serum complement 3(C3) levels, and it also had a negative correlation with the diastolic blood pressure, but not reach statistical significance. What is more, both hsa‐miR‐590‐3p and HMGB2 expression had a slight correlation tendency with serum Gd‐IgA1 levels in the whole population. In conclusion, HMGB2, the target gene of hsa‐miR‐590‐3p, was identified to correlate with the severity of IgAN, and this provides more clues for the pathogenesis of IgAN.

Expression analysis and implication of Rab1A in gastrointestinal relevant tumor

Gastrointestinal cancers have become increasingly prevalent worldwide. Previous studies have reported an oncogenic function of Rab1A in colorectal cancer and hepatocellular carcinomas via the mTOR pathway. However, the exact role of Rab1A in gastrointestinal cancers remains elusive. We detected significantly higher expression of Rab1A in the gastrointestinal tumor tissues compared to that in other cancer types following an in silico analysis of TGCA and GTEX databases. Furthermore, Rab1A was overexpressed in the gastrointestinal tumor tissues compared to the para-tumor tissues. Although Rab1A expression levels were not associated with the tumor-lymph node-metastasis (TNM) stage, Rab1A overexpression in the tumor tissues of a gastric cancer (GC) cohort was strongly correlated with poor prognosis in the patients. In addition, Rab1A knockdown significantly inhibited the in vitro proliferation and migration abilities of GC cells, as well as the growth of GC xenografts in vivo. Furthermore, a positive correlation was observed between Rab1A expression levels and that of different upstream/downstream mTOR targets. Taken together, Rab1A regulates the PI3K-AKT-mTORC1 pathway through the mTORC1 complex consisting of mTORC1, Rheb and Rab1A, and is a promising therapeutic target in GC.

miR‑139‑3p suppresses the invasion and migration properties of breast cancer cells by targeting RAB1A

Accumulated evidence indicates that aberrant microRNAs (miRNAs) expression plays an important role in the initiation and progression of various cancers, including breast cancer. Previous studies suggested that miR-139-3p might serve as a tumor suppressor and is downregulated in several cancer types. However, the expression patterns and exact role of miR-139-3p in breast cancer remain to be elucidated. In this study, we aimed to analyze the effect of miR-139-3p on the progression of breast cancer and the mechanism involved. Through bioinformatics analysis and in vitro experimental studies, we found that miR-139-3p was decreased in breast cancer tissues and cell lines, and decreased miR-139-3p is associated with a poor prognosis in breast cancer patients. Overexpression of miR-139-3p by transfection significantly inhibits cell proliferation, migration, and invasion of breast cancer cells. Bioinformatics analysis and luciferase reporter gene assay confirmed that RAB1A was a potential target of miR-139-3p. Furthermore, overexpression of RAB1A counteracted the suppressing effects of miR-139-3p on breast cancer cell migration, invasion and epithelial-to-mesenchymal transition (EMT). Taken together, these data suggest that miR-139-3p plays a tumor suppressive role in breast cancer by targeting RAB1A and may serve as a potential new biomarker for breast cancer prognosis.

Rab1A promotes proliferation and migration abilities via regulation of the HER2/AKT-independent mTOR/S6K1 pathway in colorectal cancer

Colorectal carcinoma (CRC) is one of the most common malignancies worldwide and the second leading cause of cancer-related deaths in the US. Recently, Rab1A has been reported to be an activator of mTORC1 and p-S6K1, which is downstream of mTORC1. However, the association between Rab1A and p-S6K1 in CRC remains elusive. In the present study, we first demonstrated that Rab1A was overexpressed in CRC tissues and Rab1A overexpression was positively related to lymph node invasion, degree of differentiation, venous invasion and tumor-node-metastasis (TNM) stage. In both TNM stage I–II and III–IV patients, Rab1A-positive patients had a shorter survival time than Rab1A-negative patients. Furthermore, in univariate and multivariate analyses, only Rab1A expression was verified as an independent prognostic factor for survival in CRC patients. The level of p-S6K1 was markedly high in CRC tissues and Rab1A expression level had a positive association with p-S6K1 level. In addition, high levels of both Rab1A and p-S6K1 were associated with a poorer prognosis compared with low expression of either Rab1A or p-S6K1 level. Moreover, high levels of both Rab1A and p-S6K1 were associated with a poorer prognosis than patients with high levels of either Rab1A or p-S6K1 alone. Finally, knockdown of Rab1A expression inhibited migration and proliferation of SW480 and HCT116 cell lines by targeting regulation of p-S6K1. Thus, our findings indicate that Rab1A plays an important role in CRC and may provide a therapeutic target for CRC, particularly for mTORC1-targeted therapy-resistant cancers.

Breast cancer cell motility is promoted by 14-3-3γ

PURPOSE

Pseudopodia are actin-rich ventral protrusions associated with cell motility and cancer cell invasion. We previously applied our established method of using excimer laser cell etching to isolate pseudopodial proteins from MDA-MB-231 breast cancer cells. We later identified 14-3-3γ as an oncogenic molecule among 46 candidate proteins that are specific to pseudopodia. The present study aimed to determine the function of 14-3-3γ in the motility of breast cancer cells.

METHODS

MDA-MB-231 cells were cultured on 3-µm porous membranes and double stained to localize 14-3-3γ and phalloidin in pseudopodia using confocal imaging. We assessed pseudopodia numbers and length, as well as migration and wound healing in MDA-MB-231 cells with knockdown and forced expression of 14-3-3γ to determine 14-3-3γ involvement in cell motility. We also immunohistochemically analyzed 14-3-3γ in human breast cancer tissues with high-grade lymphatic invasion.

RESULTS

We specifically located 14-3-3γ in pseudopodia of MDA-MB-231 cells. Knockdown and forced expression of 14-3-3γ, respectively, decreased and increased pseudopodial formation and elongation. Migration and wound healing assays also showed that 14-3-3γ knockdown and forced expression, respectively, decreased and increased the number of underside cells and acellular areas in MDA-MB-231 breast cancer cells. More 14-3-3γ was expressed in sites of lymphatic invasion, than in the center and periphery of human breast cancer tissues.

CONCLUSION

The role of 14-3-3γ in breast cancer invasiveness might be to promote cell motility. Inhibition of 14-3-3γ could, therefore, become a novel target of therapy to prevent invasion and metastasis in patients with breast cancers expressing 14-3-3γ.

Hypoxia-mediated miR-212-3p downregulation enhances progression of intrahepatic cholangiocarcinoma through upregulation of Rab1a

Rab1a, a member RAS oncogene family, has been reported playing important role in tumor proliferation and migration. However, the role of Rab1a in intrahepatic cholangiocarcinoma (ICC) is not clear. In this study, we found Rab1a was overexpressed in ICC tissues both in mRNA and protein level. Kaplan-meier analysis showed that high expression of Rab1a was associated with poor prognosis of ICC patients. Suppression of Rab1a led to lower proliferation rate and migration ability both in vitro and in vivo by inhibiting process of cell cycle and Epithelial-Mesenchymal Transition (EMT). Further study showed that Rab1a was targeting regulated by miR-212-3p.In addition, expression of Rab1a was increased while miR-212-3p was decreased under hypoxia condition. In conclusion, these findings extend our understanding of Rab1a in progression of ICC, and we found hypoxia/miR-212-3p/Rab1a pathway played important role for progression of ICC. This newly identified pathway should promote the development of novel therapeutic biomarker for ICC.

Consequences of Rab GTPase dysfunction in genetic or acquired human diseases

Rab GTPases are important regulators of intracellular membrane trafficking in eukaryotes. Both activating and inactivating mutations in Rab genes have been identified and implicated in human diseases ranging from neurological disorders to cancer. In addition, altered Rab expression is often associated with disease prognosis. As such, the study of diseases associated with Rabs or Rab-interacting proteins has shed light on the important role of intracellular membrane trafficking in disease etiology. In this review, we cover recent advances in the field with an emphasis on cellular mechanisms.

LncRNA DANCR functions as a competing endogenous RNA to regulate RAB1A expression by sponging miR-634 in glioma

Long noncoding RNA (lncRNA) differentiation antagonizing nonprotein coding RNA (DANCR) plays important regulatory roles in many solid tumors. However, the effect of DANCR in glioma progression and underlying molecular mechanisms were not entirely explored. In the present study, we determined the expression of DANCR in glioma tissues and cell lines using qRT-PCR and further defined the biological functions. Furthermore, we used luciferase reporter assay, Western blot, and RNA immunoprecipitation (RIP) to explore the underlying mechanism. Our results showed that DANCR was significantly up-regulated in glioma tissues and cell lines (U251, U118, LN229, and U87MG). High DANCR expression was correlated with advanced tumor grade. Inhibition of DANCR suppressed the glioma cells proliferation and induced cells arrested in the G0/G1 phase. In addition, we verified that DANCR could directly interact with miR-634 in glioma cells and this interaction resulted in the inhibition of downstream of RAB1A expression. The present study demonstrated that DANCR/miR-634/RAB1A axis plays crucial roles in the progression of glioma, and DANCR might potentially serve as a therapeutic target for the treatment of glioma patients.

Consequences of Rab GTPase dysfunction in genetic or acquired human diseases

Rab GTPases are important regulators of intracellular membrane trafficking in eukaryotes. Both activating and inactivating mutations in Rab genes have been identified and implicated in human diseases ranging from neurological disorders to cancer. In addition, altered Rab expression is often associated with disease prognosis. As such, the study of diseases associated with Rabs or Rab-interacting proteins has shed light on the important role of intracellular membrane trafficking in disease etiology. In this review, we cover recent advances in the field with an emphasis on cellular mechanisms.