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

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.

AKR1B10 inhibits the proliferation and migration of gastric cancer via regulating epithelial-mesenchymal transition

Gastric cancer (GC) is a common malignancy around the world with a poor prognosis. Aldo-keto reductase family 1 member B10 (AKR1B10) is indispensable to cancer development and progression, which has served as a diagnostic biomarker for tumors. In our study, we demonstrated that the expression of AKR1B10 in GC tissues was significantly lower compared with normal gastric tissues. Subgroup analysis showed that, according to the clinic-pathological factors, the effect of the AKR1B10 expression level on the prognosis of GC patients was significantly different. Moreover, reduced expression of AKR1B10 promoted the ability of GC cells in proliferation and migration. Furthermore, increased AKR1B10 levels resulted in the opposite trend in vitro. Moreover, AKR1B10 was correlated with epithelial-mesenchymal transition (EMT) in a significant way. In vivo experiment, knockdown of AKR1B10 promoted the growth of tumor, increased Vimentin, and E-cadherin significantly. In summary, AKR1B10 is considered as a tumor suppressor in GC and is a promising therapeutic target.

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.

Rab GTPases: Central Coordinators of Membrane Trafficking in Cancer

Tumor progression involves invasion, migration, metabolism, autophagy, exosome secretion, and drug resistance. Cargos transported by membrane vesicle trafficking underlie all of these processes. Rab GTPases, which, through coordinated and dynamic intracellular membrane trafficking alongside cytoskeletal pathways, determine the maintenance of homeostasis and a series of cellular functions. The mechanism of vesicle movement regulated by Rab GTPases plays essential roles in cancers. Therefore, targeting Rab GTPases to adjust membrane trafficking has the potential to become a novel way to adjust cancer treatment. In this review, we describe the characteristics of Rab GTPases; in particular, we discuss the role of their activation in the regulation of membrane transport and provide examples of Rab GTPases regulating membrane transport in tumor progression. Finally, we discuss the clinical implications and the potential as a cancer therapeutic target of Rab GTPases.

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.

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.