ANXA1 Promotes Tumor Immune Evasion by Binding PARP1 and Upregulating Stat3-Induced Expression of PD-L1 in Multiple Cancers.

The deregulation of Annexin A1 (ANXA1), a regulator of inflammation and immunity, leads to cancer growth and metastasis. However, whether ANXA1 is involved in cancer immunosuppression is still unclear. Here, we report that ANXA1 knockdown (i) dramatically downregulates programmed cell death-ligand 1 (PD-L1) expression in breast cancer, lung cancer, and melanoma cells; (ii) promotes T cell-mediated killing of cancer cells in vitro; and (iii) inhibits cancer immune escape in immune-competent mice via downregulating PD-L1 expression and increasing the number and killing activity of CD8+ T cells. Mechanistically, ANXA1 functioned as a sponge molecule for interaction of PARP1 and Stat3. Specifically, binding of ANXA1 to PARP1 decreased PARP1's binding to Stat3, which reduced poly(ADP-ribosyl)ation and dephosphorylation of Stat3 and thus, increased Stat3's transcriptional activity, leading to transcriptionally upregulated expression of PD-L1 in multiple cancer cells. In clinical samples, expression of ANXA1 and PD-L1 was significantly higher in breast cancer, non-small cell lung cancer, and skin cutaneous melanoma compared with corresponding normal tissues and positively correlated in cancer tissues. Moreover, using both ANXA1 and PD-L1 proteins for predicting efficacy of anti-PD-1 immunotherapy and patient prognosis was superior to using individual proteins. Our data suggest that ANXA1 promotes cancer immune escape via binding PARP1 and upregulating Stat3-induced expression of PD-L1, that ANXA1 is a potential new target for cancer immunotherapy, and combination of ANXA1 and PD-L1 expression is a potential marker for predicting efficacy of anti-PD-1 immunotherapy in multiple cancers.

ANXA1-derived peptide for targeting PD-L1 degradation inhibits tumor immune evasion in multiple cancers.

BACKGROUND: Immune checkpoint inhibitors (ICIs) therapy targeting programmed cell death 1 (PD-1)/programmed cell death ligand 1 (PD-L1) shows promising clinical benefits. However, the relatively low response rate highlights the need to develop an alternative strategy to target PD-1/PD-L1 immune checkpoint. Our study focuses on the role and mechanism of annexin A1 (ANXA1)-derived peptide A11 degrading PD-L1 and the effect of A11 on tumor immune evasion in multiple cancers. METHODS: Binding of A11 to PD-L1 was identified by biotin pull-down coupled with mass spectrometry analysis. USP7 as PD-L1's deubiquitinase was found by screening a human deubiquitinase cDNA library. The role and mechanism of A11 competing with USP7 to degrade PD-L1 were analyzed. The capability to enhance the T cell-mediated tumor cell killing activity and antitumor effect of A11 via suppressing tumor immune evasion were investigated. The synergistic antitumor effect of A11 and PD-L1 mAb (monoclonal antibody) via suppressing tumor immune evasion were also studied in mice. The expression and clinical significance of USP7 and PD-L1 in cancer tissues were evaluated by immunohistochemistry. RESULTS: A11 decreases PD-L1 protein stability and levels by ubiquitin proteasome pathway in breast cancer, lung cancer and melanoma cells. Mechanistically, A11 competes with PD-L1's deubiquitinase USP7 for binding PD-L1, and then degrades PD-L1 by inhibiting USP7-mediated PD-L1 deubiquitination. Functionally, A11 promotes T cell ability of killing cancer cells in vitro, inhibits tumor immune evasion in mice via increasing the population and activation of CD8+ T cells in tumor microenvironment, and A11 and PD-1 mAb possess synergistic antitumor effect in mice. Moreover, expression levels of both USP7 and PD-L1 are significantly higher in breast cancer, non-small cell lung cancer and skin melanoma tissues than those in their corresponding normal tissues and are positively correlated in cancer tissues, and both proteins for predicting efficacy of PD-1 mAb immunotherapy and patient prognosis are superior to individual protein. CONCLUSION: Our results reveal that A11 competes with USP7 to bind and degrade PD-L1 in cancer cells, A11 exhibits obvious antitumor effects and synergistic antitumor activity with PD-1 mAb via inhibiting tumor immune evasion and A11 can serve as an alternative strategy for ICIs therapy in multiple cancers.

[Cardiac Protection Mechanism and Clinical Application of Dexmedetomidine].

Dexmedetomidine is an α2 adrenoceptor agonist and has cardioprotective effect,the mechanism of which is being studied.Increasing studies have proved the clinical value of dexmedetomidine in reducing postoperative complications and improving the prognosis of patients.Therefore,this review summarizes the cardiac protection mechanism of dexmedetomidine based on the existing studies and expounds the application of dexmedetomidine in the perioperative period of cardiovascular surgery.

ANXA1­derived peptides suppress gastric and colon cancer cell growth by targeting EphA2 degradation.

EphA2 (EPH receptor A2) (erythropoietin­producing hepatocellular receptor tyrosine kinase subtype A2) plays a crucial role in human cancers, and is a promising target for the development of new anticancer drugs. In this study, we showed that the interaction of Annexin A1 (ANXA1) and EphA2 increased EphA2 stability by inhibiting its proteasome degradation in gastric cancer (GC) and colon cancer (CC) cells, and the amino acid residues 20­30 and 28­30 of ANXA1 N terminal were responsible for binding and stabilizing EphA2. Based on the amino acid residues of ANXA1 responsible for binding EphA2, we developed ANXA1­derived 3 amino acid­long (SKG) and 11 amino acid­long peptides (EYVQTVKSSKG) in fusion to cell­penetrating peptide, named as A1(28­30) and A1(20­30) respectively, and found that A1(28­30) and A1(20­30) blocked the binding of ANXA1 with EphA2, targeted EphA2 degradation, and suppressed the growth of GC and CC cells in vitro and in mice. Our data demonstrated that ANXA1 was able to bind and stabilize EphA2 in GC and CC cells, and disruption of ANXA1­EphA2 interaction by the two ANXA1­derived peptides inhibited the growth of GC and CC cells by targeting EphA2 degradation, presenting a potential strategy for treating GC and CC with these peptides.

Y772 phosphorylation of EphA2 is responsible for EphA2-dependent NPC nasopharyngeal carcinoma growth by Shp2/Erk-1/2 signaling pathway.

EphA2 is an important oncogenic protein and emerging drug target, but the oncogenic role and mechanism of ligand-independent phosphorylation of EphA2 at tyrosine 772 (pY772-EphA2) is unclear. In this study, we established nasopharyngeal carcinoma (NPC) cell lines with stable expression of exogenous EphA2 and EphA2-Y772A (phosphorylation inactivation) using endogenous EphA2-knockdown cells, and observed that pY772A EphA2 was responsible for EphA2-promoting NPC cell proliferation and anchorage-independent and in vivo growth in mice. Mechanistically, EphA2-Y772A mediated EphA2-activating Shp2/Erk-1/2 signaling pathway in the NPC cells, and Gab1 (Grb2-associated binder 1) and Grb2 (growth factor receptor-bound protein 2) were involved in pY772-EphA2 activating this signaling pathway. Our results further showed that Shp2/Erk-1/2 signaling mediated pY772-EphA2-promoting NPC cell proliferation and anchorage-independent growth. Moreover, we observed that EphA2 tyrosine kinase inhibitor ALW-II-41-27 inhibited pY772-EphA2 and EphA2-Y772A decreased the inhibitory effect of ALW-II-41-27 on NPC cell proliferation. Collectively, our results demonstrate that pY772-EphA2 is responsible for EphA2-dependent NPC cell growth in vitro and in vivo by activating Shp2/Erk-1/2 signaling pathway, and is a pharmacologic target of ALW-II-41-27, suggesting that pY772-EphA2 can serve as a therapeutic target in NPC and perhaps in other cancers.

ANXA1 Binds and Stabilizes EphA2 to Promote Nasopharyngeal Carcinoma Growth and Metastasis.

Overexpression of ANXA1 and EphA2 has been linked to various cancers and both proteins have attracted considerable attention for the development of new anticancer drugs. Here we report that ANXA1 competes with Cbl for binding EphA2 and increases its stability by inhibiting Cbl-mediated EphA2 ubiquitination and degradation in nasopharyngeal carcinoma (NPC). Binding of ANXA1 to EphA2 promoted NPC cell growth and metastasis in vitro and in vivo by elevating EphA2 levels and increasing activity of EphA2 oncogenic signaling (pS897-EphA2). Expression of ANXA1 and EphA2 was positively correlated and both were significantly higher in NPC tissues than in the normal nasopharyngeal epithelial tissues. Patients with high expression of both proteins presented poorer disease-free survival and overall survival relative to patients with high expression of one protein alone. Furthermore, amino acid residues 20-30aa and 28-30aa of the ANXA1 N-terminus bound EphA2. An 11 amino acid-long ANXA1-derived peptide (EYVQTVKSSKG) was developed on the basis of this N-terminal region, which disrupted the connection of ANXA1 with EphA2, successfully downregulating EphA2 expression and dramatically suppressing NPC cell oncogenicity in vitro and in mice. These findings suggest that ANXA1 promotes NPC growth and metastasis via binding and stabilization of EphA2 and present a strategy for targeting EphA2 degradation and treating NPC with a peptide. This therapeutic strategy may also be extended to other cancers with high expression of both proteins. SIGNIFICANCE: These findings show that EphA2 is a potential target for NPC therapeutics and an ANXA1-derived peptide suppresses NPC growth and metastasis. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/20/4386/F1.large.jpg.

High-energy x-ray radiation effects on the exfoliated quasi-two-dimensional ß-Ga2O3 nanoflake field-effect transistors.

The effects of x-ray irradiation on the mechanically exfoliated quasi-two-dimensional (quasi-2D) ß-Ga2O3 nanoflake field-effect transistors (FETs) under the condition of biasing voltage were systematically investigated for the first time. It has been revealed that the device experienced two stages during irradiation. At low ionizing doses (<240 krad), the device performance is mainly influenced by the photo-effect and the subsequent persistent photocurrent (PPC) effect as a result of the pre-existing electron traps (e-trap) in the oxides far away from the SiO2/ß-Ga2O3 interface. At larger doses (>240 krad), the device characteristics are dominated by the radiation-induced structural or compositional deterioration. The newly-generated e-traps are found located at the SiO2/ß-Ga2O3 interface. This study shed light on the future radiation-tolerant device fabrication process development, paving a way towards the feasibility and practicability of ß-Ga2O3-based devices in extreme-environment applications.

HDAC7 promotes the oncogenicity of nasopharyngeal carcinoma cells by miR-4465-EphA2 signaling axis.

HDAC7 plays a crucial role in cancers, and is the main drug target of several HDAC inhibitors. However, the role and mechanism of HDAC7 in nasopharyngeal carcinoma (NPC) are still unclear. In this study, we observed that HDAC7 was significantly upregulated in the NPC tissues relative to normal nasopharyngeal mucosa (NNM) tissues, HDAC7 expression levels were positively correlated with NPC progression and negatively correlated with patient prognosis, and HDAC7 knockdown dramatically inhibited the in vitro proliferation, migration, and invasion of NPC cells, and the growth of NPC xenografts in mice, indicating the HDAC7 promotes the oncogenicity of NPC. Mechanistically, HDAC7 promoted the in vitro proliferation, migration, and invasion of NPC cells by upregulating EphA2, in which miR-4465 mediated HDAC7-regulating EphA2, a direct target gene of miR-4465. We further showed that miR-4465 was significantly downregulated in the NPC tissues relative to NNM tissues, and inhibited the in vitro proliferation, migration, and invasion of NPC cells by targeting EphA2 expression. Moreover, we observed that the expressions of HDAC7, miR-4465, and EphA2 in NPC tissues were correlated. The results suggest that HDAC7 promotes the oncogenicity of NPC by downregulating miR-4465 and subsequently upregulating EphA2, highlighting HDAC7 as a potential therapeutic target for NPC.

Heterozygous p53-R280T Mutation Enhances the Oncogenicity of NPC Cells Through Activating PI3K-Akt Signaling Pathway.

A heterozygous point mutation of p53 gene at codon 280 from AGA to ACA (R280T) frequently occurs in nasopharyngeal carcinoma (NPC) cell lines, and about 10% NPC tissues. However, the role of this mutation in the pathogenesis of NPC remains unclear. In this study, we generated p53 knockout (KO) NPC cell lines from CNE2 cells carrying heterozygous p53 R280T (p53-R280T) mutation and C666-1 cells carrying wild-type p53 by CRISPR-Cas9 gene editing system, and found that KO of heterozygous p53-R280T significantly decreased NPC cell proliferation and increased NPC cell apoptosis, whereas KO of wild-type p53 had opposite effects on NPC cell proliferation and apoptosis. Moreover, KO of heterozygous p53-R280T inhibited the anchorage-independent growth and in vivo tumorigenicity of NPC cells. mRNA sequencing of heterozygous p53-R280T KO and control CNE2 cells revealed that heterozygous p53-R280T mutation activated PI3K-Akt signaling pathway. Moreover, blocking of PI3K-Akt signaling pathway abolished heterozygous p53-R280T mutation-promoting NPC cell proliferation and survival. Our data indicate that p53 with heterozygous R280T mutation functions as an oncogene, and promotes the oncogenicity of NPC cells by activating PI3K-Akt signaling pathway.

MiR-199a-5p represses the stemness of cutaneous squamous cell carcinoma stem cells by targeting Sirt1 and CD44ICD cleavage signaling.

Tumorigenic cancer stem cells (CSCs) exist in various tumors including the cutaneous squamous cell carcinoma (cSCC) as a minor subpopulation and are tightly associated with metastasis and therapeutic resistance. Better understanding of CSCs properties is essential for the novel therapeutic strategy targeted toward these cancers. The cSCC stem cells (cSCCSCs) were enriched from a cSCC cell line A431 by repeated sphere culture, and identified via the expression analysis of stemness marker genes and CD44 proteolysis. MiR-199a-5p was previously reported to be related with the proteolysis modulation of CD44, so the specific regulation mechanisms were verified by overexpression in vitro and in vivo. MiR-199a-5p is under-expressed in cSCCSCs and functions as a tumor suppressive molecule. Overexpression of miR-199a-5p reduced the stemness of cSCCSCs and inhibited cell proliferation. By targeting the deacetylase Sirt1, miR-199a-5p inhibited cellular proteolysis of CD44 and reduced the CD44 intracellular domain (CD44ICD) release and nuclear translocation. Overexpression of CD44ICD reversed the effects of miR-199a-5p overexpression or Sirt1 silencing, and increased the transcriptional expression of stemness genes. Our results revealed that the miR-199a-5p/Sirt1/CD44ICD signaling pathway regulates cSCCSCs progression by affecting its migration ability and tumorigenicity, therefore can be utilized to develop a curative approach for cSCC.Abbreviations: CSCs: cancer stem cells; cSCC cutaneous squamous cell carcinoma; cSCCSCs: cSCC stem cells; CD44ICD: CD44 intracellular domain; HA: hyaluronic acid; HNSCC: hand and neck squamous cell carcinoma; ESCC: esophageal squamous cell carcinoma;MMPs: matrix metalloproteinases; SFM: sphere formation medium; EGF: epidermal growth factor; bFGF: basic fibroblast growth factor; BSA: bovine serum albumin; CCK-8: cell counting kit-8.

S897 phosphorylation of EphA2 is indispensable for EphA2-dependent nasopharyngeal carcinoma cell invasion, metastasis and stem properties.

Our phosphoproteomics identified that phosphorylation of EphA2 at serine 897 (pS897-EphA2) was significantly upregulated in the high metastatic nasopharyngeal carcinoma (NPC) cells relative to non-metastatic NPC cells. However, the role and underlying mechanism of pS897-EphA2 in cancer metastasis and stem properties maintenance remain poorly understood. In this study, we established NPC cell lines with stable expression of exogenous EphA2 and EphA2-S897A using endogenous EphA2 knockdown cells, and observed that pS897-EphA2 maintained EphA2-dependent NPC cell in vitro migration and invasion, in vivo metastasis and cancer stem properties. Using phospho-kinase antibody array to identify signaling downstream of pS897-EphA2, we found that AKT/Stat3 signaling mediated pS897-EphA2-promoting NPC cell invasion, metastasis and stem properties, and Sox-2 and c-Myc were the effectors of pS897-EphA2. Immunohistochemistry showed that pS897-EphA2 was positively correlated with NPC metastasis and negatively correlated with patient overall survival. Moreover, ERK/RSK signaling controlled serum-induced pS897-EphA2 in NPC cells. Collectively, our results demonstrate that pS897-EphA2 is indispensable for EphA2-dependent NPC cell invasion, metastasis and stem properties by activating AKT/Stat3/Sox-2 and c-Myc signaling pathway, suggesting that pS897-EphA2 can serve as a therapeutic target in NPC and perhaps in other cancers.

[Corrigendum] ANXA1­derived peptides suppress gastric and colon cancer cell growth by targeting EphA2 degradation.

Following the publication of the above article, the authors have realized that one of the data panels featured in Fig. 5D was selected incorrectly. Specifically, the wrong image was selected for the A1 (28­30), HCT116 experiment. The authors have revisited their original sources to identify the correct data panel, and can confirm that the error arose unintentionally during the process of compiling the figure. The correct version of Fig. 5, featuring corrected data panel for Fig. 5D, is shown on the next page. The authors confirm that this error did not affect the conclusions reported in this study, and are grateful to the Editor of International Journal of Oncology for allowing them the opportunity to publish this corrigendum. Furthermore, the authors apologize to the readership of the Journal for any inconvenience caused. [the original article was published in International Journal of Oncology 57: 1203­1213, 2020; DOI: 10.3892/ijo.2020.5119].

Annexin A1-suppressed autophagy promotes nasopharyngeal carcinoma cell invasion and metastasis by PI3K/AKT signaling activation.

Annexin A1 (ANXA1) is dysregulated in the various tumors. However, the role and mechanism of ANXA1 in the cancers are poorly understood. In this study, we first showed a clinically positive correlation between ANXA1 and autophagy-associated protein SQSTM1 expression in nasopharyngeal carcinoma (NPC) and ANXA1-regulating SQSTM1 expression through autophagy, and further demonstrated that ANXA1 inhibited BECN1 and ATG5-dependent autophagy in the NPC cells. Using phospho-kinase antibody array to identify signaling through which ANXA1 regulated NPC cell autophagy, we found that ANXA1-suppressed autophagy was associated with PI3K/AKT signaling activation. We also showed that ANXA1 expression was significantly increased in the NPCs with metastasis relative to NPCs without metastasis and positively correlated with lymphonode and distant metastasis; high ANXA1 expression in the NPC cells promoted in vitro tumor cell migration and invasion and in vivo metastasis. Lastly, we showed that inhibition of autophagy restored the ability of tumor cell migration and invasion, epithelial-mesenchymal transition (EMT)-like alterations and in vivo metastasis in the ANXA1 knockdown NPC cells with autophagy activation; ANXA1-suppresed autophagy induced EMT-like alterations possibly by inhibiting autophagy-mediated degradation of Snail. Our data suggest that ANXA1-suppressed autophagy promotes NPC cell migration, invasion and metastasis by activating PI3K/AKT signaling pathway, highlighting that the activation of autophagy may inhibit metastasis of NPC with high ANXA1 expression.

RACK1 promotes tumorigenicity of colon cancer by inducing cell autophagy.

RACK1 is upregulated in the various types of human cancers, and considered to play a role in the development and progression of human cancer. However, the role and mechanism of RACK in the colon cancer are poorly understood. In this study, we detected RACK1 expression in 63 normal colonic mucosa, 60 colonic inflammatory polyps, 60 colonic adenomas, 180 colon adenocarcinomas, and 40 lymph node metastases by immunohistochemistry, and observed that RACK1 expression was progressively elevated in the carcinogenic process of human colonic epithelium, and RACK1 expressional levels were positively correlated with the malignant degree and lymph node metastasis of colon cancers, and negatively correlated with the patient survival. With a combination of loss-of-function and gain-of-function approaches, we observed that RACK1 promoted colon cancer cell proliferation, inhibited colon cancer cell apoptosis, and enhanced the anchorage-independent and xenograft growth of colon cancer cells. Moreover, we found that RACK1-induced autophagy of colon cancer cells; RACK1-induced autophagy promoted colon cancer cell proliferation and inhibited colon cancer cell apoptosis. Our data suggest that RACK1 acts as an oncogene in colon cancer, and RACK1-induced autophagy promotes proliferation and survival of colon cancer, highlighting the therapeutic potential of autophagy inhibitor in the colon cancer with high RACK1 expression.

A complex microsatellite at chromosome 7q33 as a new prognostic marker of colorectal cancer.

Disease-specific markers are critical for early diagnosis, targeted therapy and prognostic prediction of diseases. Current study reports a complex microsatellite as a new prognostic marker of sporadic colorectal cancer. This microsatellite located at Chromosome 7q33 is composed of three tetranucleotide tandem repeats, (TTCC)2(TCCC)5(TCCT)7, flanked by a CT-rich sequence. We analyzed polymorphisms of this microsatellite in 158 sporadic colorectal cancer, 143 matched normal adjacent tissues (NAT) and 150 health donors. Our results showed that this complex microsatellite was instable with polymorphic frequency of 77.2% in colorectal cancer, 52.4% in NAT and 54.7% in health donors (p<0.01) when compared to reference sequence. In the three tandem repeats, (TCCT)7 site was most polymorphic accounting for over 70.0% of polymorphisms in this complex microsatellite, followed by (TTCC)2 site for approximately 20%. Polymorphisms in (TCCC)5 was rare. Polymorphisms at the (TCCT)7 site were mainly insertions of 1 to 4 copies of TCCT (88.6%), and deletions occurred in about 6.4% of cases. The (TTCC)2 site was featured with one copy TTCC insertions. Pair-wise analyses between colorectal tumors and NAT revealed that 88 of 121 (72.7%) tumors displayed expansion, contraction or both in these tetranucleotide tandem repeats when compared to NAT. A cross-analysis with clinicopathological data of 158 colorectal cancers revealed that polymorphic alterations of the microsatellite associated with less lymphatic metastasis (p<0.001), and the colorectal cancer patients with polymorphic changes in this microsatellite demonstrated better survival (n=112, p=0.0058). Together these data suggest that this complex microsatellite is a potential prognostic marker of sporadic colorectal cancer.

MiR-125b Increases Nasopharyngeal Carcinoma Radioresistance by Targeting A20/NF-κB Signaling Pathway.

Radioresistance poses a major challenge in nasopharyngeal carcinoma (NPC) treatment, but little is known about how miRNA regulates this phenomenon. In this study, we investigated the function and mechanism of miR-125b in NPC radioresistance, one of upregulated miRNAs in the radioresistant NPC cells identified by our previous microarray analysis. We observed that miR-125b was frequently upregulated in the radioresistant NPCs, and its increment was significantly correlated with NPC radioresistance, and was an independent predictor for poor patient survival. In vitro radioresponse assays showed that miR-125b inhibitor decreased, whereas miR-125b mimic increased NPC cell radioresistance. In a mouse model, therapeutic administration of miR-125b antagomir dramatically sensitized NPC xenografts to irradiation. Mechanistically, we confirmed that A20 was a direct target of miR-125b and found that miR-125b regulated NPC cell radioresponse by targeting A20/NF-κB signaling. With a combination of loss-of-function and gain-of-function approaches, we further showed that A20 overexpression decreased while A20 knockdown increased NPC cell radioresistance both in vitro and in vivo Moreover, A20 was significantly downregulated while p-p65 (RelA) significantly upregulated in the radioresistant NPCs relative to radiosensitive NPCs, and miR-125b expression level was negatively associated with A20 expression level, whereas positively associated with p-p65 (RelA) level. Our data demonstrate that miR-125b and A20 are critical regulators of NPC radioresponse, and high miR-125b expression enhances NPC radioresistance through targeting A20 and then activating the NF-κB signaling pathway, highlighting the therapeutic potential of the miR-125b/A20/NF-κB axis in clinical NPC radiosensitization. Mol Cancer Ther; 16(10); 2094-106. ©2017 AACR.

MiR-125b regulates proliferation and apoptosis of nasopharyngeal carcinoma by targeting A20/NF-κB signaling pathway.

MiR-125b is aberrantly expressed and has a role in the various types of tumors. However, the role and mechanism of miR-125b in nasopharyngeal carcinoma (NPC) are unclear. In this study, we investigated the role and mechanism of miR-125b in NPC. We observed that miR-125b was significantly upregulated in the NPC tissues relative to normal nasopharyngeal mucosa (NNM), and its increment was correlated with poor patient survival, and was an independent predictor for reduced patient survival; miR-125b promoted NPC cell proliferation and inhibited NPC cell apoptosis; in a mouse model, administration of miR-125b antagomir significantly reduced the growth of NPC xenograft tumors. Mechanistically, we confirmed that A20 was a direct target of miR-125b, and found that activation of nuclear factor κB (NF-κB) signaling pathway by A20 mediated miR-125b-promoting NPC cell proliferation and -inhibiting NPC cell apoptosis. With a combination of loss-of-function and gain-of-function approaches, we further showed that A20 inhibited NPC cell proliferation, induced NPC cell apoptosis, and reduced the growth of NPC xenograft tumors. Moreover, A20 was significantly downregulated, whereas p-p65(RelA) was significantly upregulated in the NPC tissues relative to normal nasopharyngeal mucosa, and miR-125b level was negatively associated with A20 level, whereas positively associated with p-p65 level. Our data demonstrate that miR-125b regulates NPC cell proliferation and apoptosis by targeting A20/NF-κB signaling pathway, and miR-125b acts as oncogene, whereas A20 functions as tumor suppressor in NPC, highlighting the therapeutic potential of miR-125b/A20/NF-κB signaling axis in the NPC.

miR-130b regulates the proliferation, invasion and apoptosis of glioma cells via targeting of CYLD.

MicroRNAs are short non-coding RNAs that play important roles in gliomas. However, the role of miR-130b in glioma remains unclear. In the present study, miR-130b expression was upregulated in glioma tissues and cell lines. Kaplan-Meier analysis indicated that the upregulation of miR-130b expression correlated with poor prognoses in glioma patients. Multivariate analysis demonstrated that this upregulation and a high-grade classification were independent factors that both predicted poor outcomes for glioma patients. Dual-luciferase assays identified that the cylindromatosis (CYLD) gene is a direct target of miR-130b. Functional studies demonstrated that a miR-130b mimic significantly promoted the growth and invasion of glioma cells, while also inhibiting apoptosis via selective targeting of CYLD, which was enhanced by CYLD-targeted siRNA. In contrast, a miR­130b inhibitor suppressed these biological behaviors, and this inhibition was reversed by CYLD-targeted siRNA. These data revealed that miR-130b could act as a novel potential diagnostic biomarker for glioma, while also demonstrating the importance of miR­130b in the cell proliferation and progression of glioma, indicating that it may serve as a useful therapeutic target for glioma.

Reduced RKIP enhances nasopharyngeal carcinoma radioresistance by increasing ERK and AKT activity.

Raf kinase inhibitory protein (RKIP) functions as a chemo-immunotherapeutic sensitizer of cancers, but regulation of RKIP on tumor radiosensitivity remains largely unexplored. In this study, we investigate the role and mechanism of RKIP in nasopharyngeal carcinoma (NPC) radioresistance. The results showed that RKIP was frequently downregulated in the radioresistant NPC tissues compared with radiosensitive NPC tissues, and its reduction correlated with NPC radioresistance and poor patient survival, and was an independent prognostic factor. In vitro radioresponse assay showed that RKIP overexpression decreased while RKIP knockdown increased NPC cell radioresistance. In the NPC xenografts, RKIP overexpression decreased while RKIP knockdown increased tumor radioresistance. Mechanistically, RKIP reduction promoted NPC cell radioresistance by increasing ERK and AKT activity, and AKT may be a downstream transducer of ERK signaling. Moreover, the levels of phospho-ERK-1/2 and phospho-AKT were increased in the radioresistant NPC tissues compared with radiosensitive ones, and negatively associated with RKIP expression, indicating that RKIP-regulated NPC radioresponse is mediated by ERK and AKT signaling in the clinical samples. Our data demonstrate that RKIP is a critical determinant of NPC radioresponse, and its reduction enhances NPC radioresistance through increasing ERK and AKT signaling activity, highlighting the therapeutic potential of RKIP-ERK-AKT signaling axis in NPC radiosensitization.