Downregulation of p57kip2 promotes cell invasion via LIMK/cofilin pathway in human nasopharyngeal carcinoma cells

The members of Rho family are well known for their regulation of actin cytoskeleton to control cell migration. The Cip/kip members of cyclin‐dependent (CDK) inhibitors have shown to implicate in cell migration and cytoskeletal dynamics. p57^kip2, a CDK inhibitor, is frequently down‐regulated in several malignancy tumors. However, its biological roles in human nasopharyngeal carcinoma (NPC) cells remained to be investigated. Here, we found p57^kip2 has nuclear and cytoplasm distributions and depletion of endogenous p57^kip2 did not change the cell‐cycle progression. Inhibition of cell proliferation by mitomycin C promoted FBS‐mediated cell migration and accompanied with the downregulation of ΔNp63α and p57^kip2, but did not change the level of p27^kip1, another CDK inhibitor. By using siRNA transfection and cell migration/invasion assays, we found that knockdown of p57^kip2, but not ΔNp63α, involved in promotion of NPC cell migration and invasion via decrease of phospho‐cofilin (p‐cofilin). Treatment with Y‐27632, a specific ROCK inhibitor, we found that dysregulation of ROCK/cofilin pathway decreased p‐cofilin expression and induced cell migration. This change of p‐cofilin induced actin remodeling and pronounced increase of membrane protrusions. Further, silence of p57^kip2 not only decreased the interaction between p57^kip2 and LIMK‐1 assayed by immunoprecipitation but also reduced the level of phospho‐LIMK1/2. Therefore, this study indicated that dysregulation of p57^kip2 promoted cell migration and invasion through modulation of LIMK/cofilin signaling and suggested this induction of inappropriate cell motility might contribute to promoting tumor cell for metastasis. J. Cell. Biochem. 112: 3459–3468, 2011. © 2011 Wiley Periodicals, Inc.     

miR‐346 promotes migration and invasion of nasopharyngeal carcinoma cells via targeting BRMS1

The aim of this study is to determine the expression and roles of miR‐346 in nasopharyngeal carcinoma (NPC). We showed that miR‐346 was upregulated in NPC tissues compared with adjacent non‐tumorous nasopharyngeal tissues. Inhibition of miR‐346 significantly attenuated the migration and invasion of NPC cells. Luciferase reporter assay showed that miR‐346 targeted the 3′‐untranslated region (3′‐UTR) of breast cancer metastasis suppressor 1 (BRMS1). Overexpression of miR‐346 suppressed the endogenous expression of BRMS1 in NPC cells. There was a significant negative correlation between miR‐346 and BRMS1 protein expression in NPC tissues (r = ?0.372, P = 0.008). Rescue experiments demonstrated that overexpression of BRMS1 lacking the 3′‐UTR impaired the invasiveness of NPC cells transfected with miR‐346 mimic. Taken together, miR‐346 shows the ability to promote the migration and invasion of nasopharyngeal cancer cells via targeting BRMS1 and represents a potential therapeutic target for NPC.     

Sunitinib treatment promotes metastasis of drug-resistant renal cell carcinoma via TFE3 signaling pathway

Receptor tyrosine kinase (RTK) inhibitors, such as sunitinib and sorafenib, remain the first-line drugs for the treatment of mRCC. Acquired drug resistance and metastasis are the main causes of treatment failure. However, in the case of metastasis Renal Cell Cancer (mRCC), which showed a good response to sunitinib, we found that long-term treatment with sunitinib could promote lysosome biosynthesis and exocytosis, thereby triggering the metastasis of RCC. By constructing sunitinib-resistant cell lines in vivo, we confirmed that TFE3 plays a key role in the acquired resistance to sunitinib in RCC. Under the stimulation of sunitinib, TFE3 continued to enter the nucleus, promoting the expression of endoplasmic reticulum (ER) protein E-Syt1. E-Syt1 and the lysosomal membrane protein Syt7 form a heterodimer, which induces ER fragmentation, Ca2⁺ release, and lysosomal exocytosis. Lysosomal exocytosis has two functions: pumping sunitinib out from the cytoplasm, which promotes resistance to sunitinib in RCC, releasing cathepsin B (CTSB) into the extracellular matrix (ECM), which can degrade the ECM to enhance the invasion and metastasis ability of RCC. Our study found that although sunitinib is an effective drug for the treatment of mRCC, once RCC has acquired resistance to sunitinib, sunitinib treatment will promote metastasis.Subject terms: Renal cell carcinoma, Cell invasion, Prognostic markers     

Glutaredoxin 3 promotes migration and invasion via the Notch signalling pathway in oral squamous cell carcinoma

Substantial evidence indicates that the alteration of the cellular redox status is a critical factor involved in cell growth and death and results in tumourigenesis. Cancer cells have an efficient antioxidant system to counteract the increased generation of ROS. However, whether this ability to survive high levels of ROS has an important role in the growth and metastasis of tumours is not well understood. Glutaredoxin 3 (GLRX3), also known as TXNL2, Grx3 and PICOT, maintains a low level of ROS, thus contributing to the survival and metastasis of several types of cancer. However, little is known about the role of GLRX3 and the underlying mechanisms that suppress oral squamous cell carcinoma (OSCC) progression. Here, by using immunohistochemical staining, we demonstrated that GLRX3 was overexpressed in human OSCC, and enhanced GLRX3 expression correlated with metastasis and with decreased overall patient survival. Knockdown of GLRX3 in human OSCC cell lines reduced Notch activity by reversing the epithelial–mesenchymal transition (EMT), resulting in the inhibition of in vitro migration and invasion. Importantly, knockdown of GLRX3 triggered the generation of ROS. Furthermore, N-acetyl cysteine (NAC), an ROS scavenger, enhanced the effects of GLRX3 knockdown on Notch-dependent EMT. Collectively, these findings suggested the vital roles of GLRX3 in OSCC progression through its relationship with EMT progression, and these data also suggest that a strategy of blocking ROS to enhance the activity of GLRX3 knockdown warrants further attention in the treatment of OSCC.     

PKM2 promotes cell metastasis and inhibits autophagy via the JAK/STAT3 pathway in hepatocellular carcinoma

Molecular and Cellular Biochemistry - Pyruvate kinase M2 (PKM2) is a member of the pyruvate kinase family. It has been recently reported that PKM2 displays non-metabolic activities. Nevertheless,...     

KPNA2 promotes renal cell carcinoma proliferation and metastasis via NPM

Karyopherin α2 (KPNA2), involved in nucleocytoplasmic transport, has been reported to be up-regulated in tumorigenesis. However, comprehensive studies of KPNA2 functions in renal cell carcinoma (RCC) are still lacking. In this study, we aim to investigate the roles of KPNA2 in kidney tumour development. Our results showed that down-regulation of KPNA2 inhibited the proliferation and invasion of kidney tumour cell cells in vitro, while the cell cycle arrest and cellular apoptosis were induced once KPNA2 was silenced. Repression of KPNA2 was proved to be efficient to repress tumorigenesis and development of kidney tumour in in nude mice. Furthermore, one related participator, NPM, was identified based on Co-IP/MS and bioinformatics analyses. The up-regulation of NPM attenuates the efficiency of knockdown KPNA2. These results indicated that KPNA2 may regulate NPM to play a crucial role for kidney tumour development.     

SNX9 promotes metastasis by enhancing cancer cell invasion via differential regulation of RhoGTPases

Despite current advances in cancer research, metastasis remains the leading factor in cancer-related deaths. Here we identify sorting nexin 9 (SNX9) as a new regulator of breast cancer metastasis. We detect an increase in SNX9 expression in human breast cancer metastases compared with primary tumors and demonstrate that SNX9 expression in MDA-MB-231 breast cancer cells is necessary to maintain their ability to metastasize in a chick embryo model. Conversely, SNX9 knockdown impairs this process. In vitro studies using several cancer cell lines derived from a variety of human tumors reveal a role for SNX9 in cell invasion and identify mechanisms responsible for this novel function. We show that SNX9 controls the activation of RhoA and Cdc42 GTPases and also regulates cell motility via the modulation of well-known molecules involved in metastasis, namely RhoA-ROCK and N-WASP. In addition, we find that SNX9 is required for RhoGTPase-dependent, clathrin-independent endocytosis, and in this capacity can functionally substitute to the bona fide Rho GAP, GTPase regulator associated with focal adhesion kinase (GRAF1). Taken together, our data establish novel roles for SNX9 as a multifunctional protein scaffold that regulates, and potentially coordinates, several cellular processes that together can enhance cancer cell metastasis.     

Synthetic curcumin analog: inhibiting the invasion,angiogenesis, and metastasis in human laryngeal carcinoma cells via NF-kB pathway

Molecular Biology Reports - Laryngeal carcinoma, the most common among head and neck squamous cell carcinoma (HNSCC), induces 1% of all cancer deaths. Curcumin the active constituent of turmeric,...     

TIPE1‐mediated autophagy suppression promotes nasopharyngeal carcinoma cell proliferation via the AMPK/mTOR signalling pathway

Recent studies have shown that tumour necrosis factor‐α–induced protein 8 like‐1(TIPE1) plays distinct roles in different cancers. TIPE1 inhibits tumour proliferation and metastasis in a variety of tumours but acts as an oncogene in cervical cancer. The role of TIPE1 in nasopharyngeal carcinoma (NPC) remains unknown. Interestingly, TIPE1 expression was remarkably increased in NPC tissue samples compared to adjacent normal nasopharyngeal epithelial tissue samples in our study. TIPE1 expression was positively correlated with that of the proliferation marker Ki67 and negatively correlated with patient lifespan. In vitro, TIPE1 inhibited autophagy and induced cell proliferation in TIPE1‐overexpressing CNE‐1 and CNE‐2Z cells. In addition, knocking down TIPE1 expression promoted autophagy and decreased proliferation, whereas overexpressing TIPE1 increased the levels of pmTOR, pS6 and P62 and decreased the level of pAMPK and the LC3B. Furthermore, the decrease in autophagy was remarkably rescued in TIPE1‐overexpressing CNE‐1 and CNE‐2Z cells treated with the AMPK activator AICAR. In addition, TIPE1 promoted tumour growth in BALB/c nude mice. Taken together, results indicate that TIPE1 promotes NPC progression by inhibiting autophagy and inducing cell proliferation via the AMPK/mTOR signalling pathway. Thus, TIPE1 could potentially be used as a valuable diagnostic and prognostic biomarker for NPC.     

ANKRD49 promotes the invasion and metastasis of lung adenocarcinoma via a P38/ATF‐2 signalling pathway

Lung adenocarcinoma (LUAD) is the most challenging neoplasm to treat in clinical practice. Ankyrin repeat domain 49 protein (ANKRD49) is highly expressed in several carcinomas; however, its pattern of expression and role in LUAD are not known. Tissue microarrays, immunohistochemistry, χ ² test, Spearman correlation analysis, Kaplan–Meier, log‐rank test, and Cox''s proportional hazard model were used to analyse the clinical cases. The effect of ANKRD49 on the LUAD was investigated using CCK‐8, clonal formation, would healing, transwell assays, and nude mice experiment. Expressions of ANKRD49 and its associated downstream protein molecules were verified by real‐time PCR, Western blot, immunohistochemistry, and/or immunofluorescence analyses. ANKRD49 expression was highly elevated in LUAD. The survival rate and Cox''s modelling analysis indicated that there may be an independent prognostic indicator for LUAD patients. We also found that ANKRD49 promoted the invasion and migration in both in in vitro and in vivo assays, through upregulating matrix metalloproteinase (MMP)‐2 and MMP‐9 activities via the P38/ATF‐2 signalling pathway Our findings suggest that ANKRD49 is a latent biomarker for evaluating LUAD prognosis and promotes the metastasis of A549 cells via upregulation of MMP‐2 and MMP‐9 in a P38/ATF‐2 pathway‐dependent manner.     

Nuclear exosome HMGB3 secreted by nasopharyngeal carcinoma cells promotes tumour metastasis by inducing angiogenesis

Distant metastasis accompanied by angiogenesis is the main cause of nasopharyngeal carcinoma (NPC)-related death. Nuclear exosomes (nEXOs) are potential tumour biomarkers. High mobility group box 3 (HMGB3), a nuclear protein, is known to be overexpressed in cancers. However, its role in NPC has not been elucidated. Here, we explore for the first time the function of nEXO HMGB3 in tumour angiogenesis involved in NPC metastasis using a series of in vitro experiments with NPC cell lines and clinical specimens and in vivo experiments with tumour xenograft zebrafish angiogenesis model. We found a high expression of HMGB3 in NPC, accompanied by the formation of micronuclei, to be associated with metastasis. Furthermore, the NPC-secreted HMGB3 expression was associated with tumour angiogenesis. Moreover, HMGB3-containing nEXOs, derived from the micronuclei of NPC cells, were ingested by the human umbilical vein endothelial cells (HUVECs), and accelerated angiogenesis in vitro and in vivo. Importantly, western blotting and flow cytometry analysis showed that circulating nEXO HMGB3 positively correlated with NPC metastasis. In summary, nEXO HMGB3 can be a significant biomarker of NPC metastasis and provide a novel basis for anti-angiogenesis therapy in clinical metastasis.Subject terms: Metastasis, Tumour angiogenesis     

Nogo-B promotes angiogenesis and improves cardiac repair after myocardial infarction via activating Notch1 signaling

Nogo-B (Reticulon 4B) is reportedly a regulator of angiogenesis during the development and progression of cancer. However, whether Nogo-B regulates angiogenesis and post-myocardial infarction (MI) cardiac repair remains elusive. In the present study, we aimed to explore the role and underlying mechanisms of Nogo-B in cardiac repair during MI. We observed an increased expression level of Nogo-B in the heart of mouse MI models, as well as in isolated cardiac microvascular endothelial cells (CMECs). Moreover, Nogo-B was significantly upregulated in CMECs exposed to oxygen-glucose deprivation (OGD). Nogo-B overexpression in the endothelium via cardiotropic adeno-associated virus serotype 9 (AAV9) with the mouse endothelial-specific promoter Tie2 improved heart function, reduced scar size, and increased angiogenesis. RNA-seq data indicated that Notch signaling is a deregulated pathway in isolated CMECs along the border zone of the infarct with Nogo-B overexpression. Mechanistically, Nogo-B activated Notch1 signaling and upregulated Hes1 in the MI hearts. Inhibition of Notch signaling using a specific siRNA and γ-secretase inhibitor abolished the promotive effects of Nogo-B overexpression on network formation and migration of isolated cardiac microvascular endothelial cells (CMECs). Furthermore, endothelial Notch1 heterozygous deletion inhibited Nogo-B-induced cardioprotection and angiogenesis in the MI model. Collectively, this study demonstrates that Nogo-B is a positive regulator of angiogenesis by activating the Notch signaling pathway, suggesting that Nogo-B is a novel molecular target for ischemic disease.Subject terms: Heart failure, Ischaemia     

Rock2 promotes the invasion and metastasis of hepatocellular carcinoma by modifying MMP2 ubiquitination and degradation

Rho-associated coiled-coil-containing protein kinase 2 (Rock2) is a downstream effector of Rho that plays an important role in the tumorigenesis and progression of hepatocellular carcinoma (HCC). Matrix metalloproteinase 2 (MMP2) is a master regulator of tumor metastasis. In this study, we investigated the collections of Rock2 and MMP2 in HCCs and determined the potential role and molecular mechanism of Rock2 in MMP2-mediated invasiveness and metastasis. We found that Rock2 and MMP2 were markedly overexpressed in HCCs compared with the corresponding adjacent tissues, where a positive correlation in their expression was found. The knockdown of Rock2 significantly decreased MMP2 expression and inhibited the invasion and metastasis of HCC in vitro and in vivo. Additionally, the upregulation of MMP2 rescued the decreased migration and invasion induced by the knockdown of Rock2, whereas the knockdown of MMP2 decreased Rock2-enhanced HCC migration and invasion. Mechanistically, Rock2 stabilized MMP2 by preventing its ubiquitination and degradation. Together, our results link two drivers of invasion and metastasis in HCC and identify a novel pathway for MMP2 control.     

CircZNF609 promotes cell proliferation,migration, invasion,and glycolysis in nasopharyngeal carcinoma through regulating HRAS via miR-338-3p

Molecular and Cellular Biochemistry - Circular RNA zinc finger protein 609 (circZNF609) has been reported to involve in nasopharyngeal carcinoma (NPC) tumorigenesis regulation. However, the role...