N6-methyladenosine (m 6 A) modification plays important roles in bioprocesses and diseases. AlkB homolog 5 (ALKBH5) is one of two m 6 A demethylases. Here, we reveal that ALKBH5 is acetylated at lysine 235 (K235) by lysine acetyltransferase 8 and deacetylated by histone deacetylase 7. K235 acetylation strengthens the m 6 A demethylation activity of ALKBH5 by increasing its recognition of m 6 A on mRNA. RNA-binding protein paraspeckle component 1 (PSCP1) is a regulatory subunit of ALKBH5 and preferentially interacts with K235-acetylated ALKBH5 to recruit and facilitate the recognition of m 6 A mRNA by ALKBH5, thereby promoting m 6 A erasure. Mitogenic signals promote ALKBH5 K235 acetylation. K235 acetylation of ALKBH5 is upregulated in cancers and promotes tumorigenesis. Thus, our findings reveal that the m 6 A demethylation activity of ALKBH5 is orchestrated by its K235 acetylation and regulatory subunit PSPC1 and that K235 acetylation is necessary for the m 6 A demethylase activity and oncogenic roles of ALKBH5.

Hepatocellular carcinoma (HCC) patients mostly suffer from poor survival outcomes. It is necessary to identify effective therapeutic targets to improve prognosis for HCC patients. Here, we report a new factor, CDCA2, in promoting HCC development. CDCA2 amplification is an independent risk factor for the recurrence and survival of HCC patients, which is positively correlated with elevated level of alpha-fetoprotein (AFP), high histological grade, large tumor size, advanced TNM stage, and poor prognosis for HCC patients. In HCC cells, CDCA2 promotes cell growth and inhibits apoptosis. Mechanistically, CDCA2’s transcription is activated through the binding of E2F2/E2F8 with its promoter. CDCA2 depletion contributes to the suppression of cell proliferation and induction of apoptosis due to reactive oxygen species (ROS)-mediated stress, which can be reversed by antioxidants N -acetyl cysteine (NAC) and glutathione (GSH). Interestingly, we found that CDCA2 triggers the BRCA1–NRF2 cascade, which elevates antioxidant response and attenuates ROS levels. In response to oxidative stress, CDCA2 promotes BRCA1’s chromatin relocalization to NRF2, activating NRF2-driven downstream signaling (HO-1, TXNRD1, and NQO1), which then protects HCC cells against oxidative damage. In conclusion, our results reveal that CDCA2 is a prognostic biomarker for HCC patients, and present the E2F2/E2F8–CDCA2–BRCA1–NRF2–ROS signaling axis that have implications for HCC therapeutics.

Rationale: Hepatocellular carcinoma (HCC) is one of the most lethal cancers, and few molecularly targeted anticancer therapies have been developed to treat it. Thus, the identification of new therapeutic targets is urgent. Metabolic reprogramming is an important hallmark of cancer. However, how ubiquitin ligases are involved in the regulation of cancer metabolism remains poorly understood. Methods: RT-PCR, western blot and IHC were used to determine ZFP91 expression. RNAi, cell proliferation, colony formation and transwell assays were used to determine the in vitro functions of ZFP91. Mouse xenograft models were used to study the in vivo effects of ZFP91. Co-IP together with mass spectrometry or western blot was utilized to investigate protein-protein interaction. Ubiquitination was analyzed using IP together with western blot. RNA splicing was assessed by using RT-PCR followed by restriction digestion. Lactate production and glucose uptake assays were used to analyze cancer metabolism. Results: We identified that an E3 ligase zinc finger protein 91 (ZFP91) suppressed HCC metabolic reprogramming, cell proliferation and metastasis in vitro and in vivo. Mechanistically, ZFP91 promoted the Lys48-linked ubiquitination of the oncoprotein hnRNP A1 at lysine 8 and proteasomal degradation, thereby inhibiting hnRNP A1-dependent PKM splicing, subsequently resulting in higher PKM1 isoform formation and lower PKM2 isoform formation and suppressing HCC glucose metabolism reprogramming, cell proliferation and metastasis. Moreover, HCC patients with lower levels of ZFP91 have poorer prognoses, and ZFP91 is an independent prognostic factor for patients with HCC. Conclusions: Our study identifies ZFP91 as a tumor suppressor of hepatocarcinogenesis and HCC metabolism reprogramming and proposes it as a novel prognostic biomarker and therapeutic target of HCC.

N 6 -methyladenosine (m 6 A) is the most prevalent modification in eukaryotic RNAs. The biological importance of m 6 A relies on m 6 A readers, which control mRNA fate and function. However, it remains unexplored whether additional regulatory subunits of m 6 A readers are involved in the m 6 A recognition on RNAs. Here we discover that the long noncoding RNA (lncRNA) LINC00266-1 encodes a 71-amino acid peptide. The peptide mainly interacts with the RNA-binding proteins, including the m 6 A reader IGF2BP1, and is thus named “RNA-binding regulatory peptide” (RBRP). RBRP binds to IGF2BP1 and strengthens m 6 A recognition by IGF2BP1 on RNAs, such as c-Myc mRNA, to increase the mRNA stability and expression of c-Myc , thereby promoting tumorigenesis. Cancer patients with RBRP high have a poor prognosis. Thus, the oncopeptide RBRP encoded by LINC00266-1 is a regulatory subunit of m 6 A readers and strengthens m 6 A recognition on the target RNAs by the m 6 A reader to exert its oncogenic functions.

Conventional therapies for late-stage colorectal cancer (CRC) have limited effects because of chemoresistance, recurrence, and metastasis. The "hidden" proteins/peptides encoded by long noncoding RNAs (lncRNAs) may be a novel resource bank for therapeutic options for patients with cancer. Here, lncRNA LOC90024 is discovered to encode a small 130-amino acid protein that interacts with several splicing regulators, such as serine- and arginine-rich splicing factor 3 (SRSF3), to regulate mRNA splicing, and the protein thus is named "Splicing Regulatory Small Protein" (SRSP). SRSP, but not LOC90024 lncRNA itself, promotes CRC tumorigenesis and progression, while silencing of SRSP suppresses CRC tumorigenesis. Mechanistically, SRSP increases the binding of SRSF3 to exon 3 of transcription factor Sp4, resulting in the inclusion of Sp4 exon 3 to induce the formation of the "cancerous" long Sp4 isoform (L-Sp4 protein) and inhibit the formation of the "noncancerous" short Sp4 isoform (S-Sp4 peptide), which lacks the transactivation domain. The upregulated SRSP level is positively associated with malignant phenotypes and poor prognosis in patients with CRC. Collectively, the findings uncover that a lncRNA-encoded small protein SRSP induces "cancerous" Sp4 splicing variant formation and may be a potential prognostic biomarker and therapeutic target for patients with CRC.

目的:检测钾离子通道调节蛋白(K+ channel regulator,KCNRG)在肝癌细胞中的表达情况,并探讨上调KCNRG基因表达对肝癌细胞增殖、克隆形成、迁移、侵袭和上皮-间质转化(epithelial-mesenchymal transition,EMT)能力的影响.方法:首先采用RT-PCR、实时荧光定量PCR和蛋白质印迹法分别检测人正常肝上皮永生化细胞THLE-3和肝癌细胞BEL-7402、SMMC-7721、MHCC-LM3及SK-HEP1中KCNRG mRNA和蛋白的表达水平.然后采用脂质体转染法将KCNRG过表达质粒KCNRG-pcDNA3.1(+)转染至肝癌细胞SK-HEP1和MHCC-LM3中,同时设置未转染的空白对照组和转染空载体的阴性对照组.采用实时荧光定量PCR和蛋白质印迹法验证KCNRG过表达效果后,分别采用细胞计数法、克隆形成实验和Transwell小室法分别检测肝癌细胞增殖、克隆形成、迁移和侵袭能力的变化情况,并采用蛋白质印迹法检测肝癌细胞中EMT标志分子的表达变化.结果:肝癌细胞中KCNRG mRNA和蛋白表达水平明显低于人正常肝上皮永生化细胞THLE-3 (P值均＜0.01),尤以肝癌细胞SK-HEP1和MHCC-LM3中的表达水平最低.KCNRG过表达质粒转染后,肝癌细胞SK-HEP1和MHCC-LM3中KCNRG基因表达水平明显上调(P值均＜0.01),N-钙黏蛋白(N-cadherin)表达水平明显下调(P值均＜0.01),E-钙黏蛋白(E-cadherin)表达水平明显上调(P值均＜0.01),并且2种肝癌细胞的增殖、克隆形成、迁移和侵袭能力均被明显抑制(P值均＜0.01).结论:肝癌细胞中KCNRG基因表达水平明显低于正常肝细胞.KCNRG基因表达上调可以抑制肝癌细胞的增殖、克隆形成、迁移、侵袭及EMT.

DNA N6-methyladenine (6mA) modification is the most prevalent DNA modification in prokaryotes, but whether it exists in human cells and whether it plays a role in human diseases remain enigmatic. Here, we showed that 6mA is extensively present in the human genome, and we cataloged 881,240 6mA sites accounting for ∼0.051% of the total adenines. [G/C]AGG[C/T] was the most significantly associated motif with 6mA modification. 6mA sites were enriched in the coding regions and mark actively transcribed genes in human cells. DNA 6mA and N6-demethyladenine modification in the human genome were mediated by methyltransferase N6AMT1 and demethylase ALKBH1, respectively. The abundance of 6mA was significantly lower in cancers, accompanied by decreased N6AMT1 and increased ALKBH1 levels, and downregulation of 6mA modification levels promoted tumorigenesis. Collectively, our results demonstrate that DNA 6mA modification is extensively present in human cells and the decrease of genomic DNA 6mA promotes human tumorigenesis.

The human ortholog of the Drosophila ecdysoneless gene (ECD) is required for embryonic development and cell-cycle progression; however, its role in cancer progression and metastasis remains unclear. Here, we found that ECD is frequently overexpressed in gastric cancer (GC), especially in metastatic GC, and is correlated with poor clinical outcomes in GC patients. Silencing ECD inhibited GC migration and invasion in vitro and metastasis in vivo, while ECD overexpression promoted GC migration and invasion. ECD promoted GC invasion and metastasis by protecting hnRNP F from ubiquitination and degradation. We identified ZFP91 as the E3 ubiquitin ligase that is responsible for hnRNP F ubiquitination at Lys 185 and proteasomal degradation. ECD competitively bound to hnRNP F via the N-terminal STG1 domain (13-383aa), preventing hnRNP F from interacting with ZFP91, thus preventing ZFP91-mediated hnRNP F ubiquitination and proteasomal degradation. Collectively, our findings indicate that ECD promotes cancer invasion and metastasis by preventing E3 ligase ZFP91-mediated hnRNP F ubiquitination and degradation, suggesting that ECD may be a marker for poor prognosis and a potential therapeutic target for GC patients.

A substantial fraction of eukaryotic transcripts are considered long non-coding RNAs (lncRNAs), which regulate various hallmarks of cancer. Here, we discovered that the lncRNA HOXB-AS3 encodes a conserved 53-aa peptide. The HOXB-AS3 peptide, not lncRNA, suppresses colon cancer (CRC) growth. Mechanistically, the HOXB-AS3 peptide competitively binds to the ariginine residues in RGG motif of hnRNP A1 and antagonizes the hnRNP A1-mediated regulation of pyruvate kinase M (PKM) splicing by blocking the binding of the ariginine residues in RGG motif of hnRNP A1 to the sequences flanking PKM exon 9, ensuring the formation of lower PKM2 and suppressing glucose metabolism reprogramming. CRC patients with low levels of HOXB-AS3 peptide have poorer prognoses. Our study indicates that the loss of HOXB-AS3 peptide is a critical oncogenic event in CRC metabolic reprogramming. Our findings uncover a complex regulatory mechanism of cancer metabolism reprogramming orchestrated by a peptide encoded by an lncRNA.

Despite recent efforts to understand activities of POU domain class 2 transcription factor 1 (POU2F1), little is known about the roles of POU2F1 in hepatocellular carcinoma (HCC) tumorigenesis and its correlation with any clinicopathological feature of HCC. In this study, we found that POU2F1 was significantly up-regulated in HCC specimens compared with adjacent non-cancerous liver specimens. The high POU2F1 protein expression level positively correlated with large tumor size, high histological grade, tumor metastasis and advanced clinical stage, and HCC patients with high POU2F1 levels exhibited poor prognoses. We further demonstrated that POU2F1 over-expression promoted HCC cell proliferation, colony formation, epithelial-to-mesenchymal transition (EMT), migration and invasion, while silencing of POU2F1 inhibited these malignant phenotypes. POU2F1 induced the expression of Twist1, Snai1, Snai2 and ZEB1 genes which are involved in the regulation of EMT. Furthermore, POU2F1 was up-regulated by AKT pathway in HCC, and POU2F1 over-expression reversed the inhibition of malignant phenotypes induced by AKT knock-down, indicating POU2F1 is a key down-stream effector of AKT pathway. Collectively, our results indicate that POU2F1 over-expression is positively associated with aggressive phenotypes and poor survival in patients with HCC, and POU2F1 regulated by AKT pathway promotes HCC aggressive phenotypes by regulating the transcription of EMT genes. POU2F1 may be employed as a new prognostic factor and therapeutic target for HCC.

Amplification or over-expression of an activated Cdc42-associated kinase 1 (ACK1) gene is common in breast, lung and ovarian cancers. However, little is known about the role of ACK1 in gastric tumorigenesis. Here, we found that DNA copy numbers of the ACK1 gene and its mRNA expression levels were significantly increased in gastric cancer (GC) compared to normal gastric tissues. Additionally, silencing ACK1 inhibited GC cell proliferation and colony formation, induced G2/M arrest and cellular apoptosis in vitro, and suppressed tumor growth in vivo. Gene Ontology annotation revealed that 147 differential proteins regulated by ACK1 knockdown were closely related with cellular survival. A cell cycle regulator, ecdysoneless homolog (ECD), was found to be significantly down-regulated by ACK1 knockdown. Silencing of ECD inhibited colony formation and induced G2/M arrest and cell apoptosis, which is similar to the effects of ACK1 knockdown. Silencing of ECD did not further enhance the effects of ACK1 knockdown on G2/M arrest and apoptosis, while silencing of ECD blocked the enhancement of colony formation by ACK1 over-expression. Over-expression of ACK or ECD promoted the ubiquitination of tumor suppressor p53 protein and decreased p53 levels, while silencing of ACK1 or ECD decreased the p53 ubiquitination level and increased p53 levels. Silencing of ECD attenuated the ubiquitination enhancement of p53 induced by ACK1 over-expression. Collectively, we demonstrate that amplification of ACK1 promotes gastric tumorigenesis by inducing an ECD-dependent ubiquitination degradation of p53.

The tricho-rhino-phalangeal syndrome 1 gene (TRPS1), which was initially found to be associated with tricho-rhino-phalangeal syndrome, is critical for the development and differentiation of bone, hair follicles and kidney. However, its role in cancer progression is largely unknown. In this study, we demonstrated that down-regulation of TRPS1 correlated with distant metastasis, tumour recurrence and poor survival rate in cancer patients. TRPS1 was frequently down-regulated in high-metastatic cancer cell lines from the breast, colon and nasopharynx. Silencing of TRPS1 stimulated epithelial-mesenchymal transition (EMT), migration and invasion in vitro and metastasis in vivo, while TRPS1 over-expression exhibited the opposite effects. Using quantitative proteomics, FOXA1, a negative regulator of epithelial-mesenchymal transition (EMT), was shown to be down-regulated by TRPS1 knockdown. Ectopic expression of FOXA1 blocked the enhancement of EMT, migration and invasion induced by TRPS1 silencing. Mechanistically, TRPS1, acting as a transcription activator, directly induced FOXA1 transcription by binding to the FOXA1 promoter. We further showed that down-regulation of TRPS1 was induced by miR-373 binding to the 3' UTR of TRPS1. Over-expression of TRPS1, but not TRPS1 3' UTR, blocked the enhancement of migration and invasion induced by miR-373. Taken together, we consider that down-regulation of TRPS1 by miR-373, acting as a transcriptional activator, promotes EMT and metastasis by repressing FOXA1 transcription, expanding upon its previously reported role as a transcription repressor. Copyright (C) 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Hepatocellular carcinoma (HCC) is a major cause of cancer‐related death worldwide and currently has the fastest rising incidence of all cancers. Sorafenib was originally identified as an inhibitor of multiple oncogenic kinases and remains the only approved systemic therapy for advanced HCC. However, acquired resistance to sorafenib has been found in HCC patients, which results in poor prognosis. Here, we show that metallothionein (MT)‐1G is a critical regulator and promising therapeutic target of sorafenib resistance in human HCC cells. The expression of MT‐1G messenger RNA and protein is remarkably induced by sorafenib but not other clinically relevant kinase inhibitors (e.g., erlotinib, gefitinib, tivantinib, vemurafenib, selumetinib, imatinib, masitinib, and ponatinib). Activation of the transcription factor nuclear factor erythroid 2‐related factor 2, but not p53 and hypoxia‐inducible factor 1‐alpha, is essential for induction of MT‐1G expression following sorafenib treatment. Importantly, genetic and pharmacological inhibition of MT‐1G enhances the anticancer activity of sorafenib in vitro and in tumor xenograft models. The molecular mechanisms underlying the action of MT‐1G in sorafenib resistance involve the inhibition of ferroptosis, a novel form of regulated cell death. Knockdown of MT‐1G by RNA interference increases glutathione depletion and lipid peroxidation, which contributes to sorafenib‐induced ferroptosis. Conclusion: These findings demonstrate a novel molecular mechanism of sorafenib resistance and suggest that MT‐1G is a new regulator of ferroptosis in HCC cells. (Hepatology 2016;64:488‐500)

Objective To develop a more effective method of reducing the background autofluorescence and research its use in rat thymus gland histological section. Methods Using the fluorescence microscope to observe the reduction of autofluorescence after preprocessing the rat thymus gland histological section with three different histochemicals including:sodium borohydride, trypan blue or Sudan Black B. The autofluorescence background was evaluated in the study of DC markers (including CD103 and CD4) by immunofluorescent double staining. Results All the autofluorescence under red light, green light and blue light were significantly reduced with preprocessing of sodium borohydride comparing to the control group, while the fluorescence of DC markers in rat thymus gland were more clearly. Furthermore, there was no distinctly differences in other treatment groups. Conclusion The autofluorescence in rat thymus gland histological section was effectively reducing by pretreating the histological sections with sodium borohydride.

Ferroptosis is a recently recognized form of regulated cell death caused by an iron‐dependent accumulation of lipid reactive oxygen species. However, the molecular mechanisms regulating ferroptosis remain obscure. Here, we report that nuclear factor erythroid 2‐related factor 2 (NRF2) plays a central role in protecting hepatocellular carcinoma (HCC) cells against ferroptosis. Upon exposure to ferroptosis‐inducing compounds (e.g., erastin, sorafenib, and buthionine sulfoximine), p62 expression prevented NRF2 degradation and enhanced subsequent NRF2 nuclear accumulation through inactivation of Kelch‐like ECH‐associated protein 1. Additionally, nuclear NRF2 interacted with transcriptional coactivator small v‐maf avian musculoaponeurotic fibrosarcoma oncogene homolog proteins such as MafG and then activated transcription of quinone oxidoreductase‐1, heme oxygenase‐1, and ferritin heavy chain‐1. Knockdown of p62, quinone oxidoreductase‐1, heme oxygenase‐1, and ferritin heavy chain‐1 by RNA interference in HCC cells promoted ferroptosis in response to erastin and sorafenib. Furthermore, genetic or pharmacologic inhibition of NRF2 expression/activity in HCC cells increased the anticancer activity of erastin and sorafenib in vitro and in tumor xenograft models. Conclusion: These findings demonstrate novel molecular mechanisms and signaling pathways of ferroptosis; the status of NRF2 is a key factor that determines the therapeutic response to ferroptosis‐targeted therapies in HCC cells. (H epatology 2016;63:173–184)

Amplification of the activated Cdc42‐associated kinase 1 ( ACK1 ) gene is frequent in gastric cancer ( GC ). However, little is known about the clinical roles and molecular mechanisms of ACK1 abnormalities in GC . Here, we found that the ACK1 protein level and ACK1 phosphorylation at Tyr 284 were frequently elevated in GC and associated with poor patient survival. Ectopic ACK1 expression in GC cells induced epithelial–mesenchymal transition ( EMT ) and promoted migration and invasion in vitro , and metastasis in vivo ; the depletion of ACK1 induced the opposite effects. We utilized SILAC quantitative proteomics to discover that the level of the cell cycle‐related protein ecdysoneless homologue ( ECD ) was markedly altered by ACK1 . Overexpression of ECD promoted EMT , migration, and invasion in GC , similar to the effects of ACK1 overexpression. Silencing of ECD completely blocked the augmentation of ACK1 overexpression‐induced EMT , migration, and invasion. Mechanistically, ACK1 phosphorylated AKT at Thr 308 and Ser 473 and activated the AKT pathway to up‐regulate the transcription factor POU2F1 , which directly bound to the promoter region of its novel target gene ECD and thus regulated ECD expression in GC cells. Furthermore, the phosphorylation levels of AKT at Thr 308 and Ser 473 and POU2F1 and ECD levels were positively associated with ACK1 levels in clinical GC specimens. Collectively, we have demonstrated that ACK1 promotes EMT , migration, and invasion by activating AKT–POU2F1–ECD signalling in GC cells. ACK1 may be employed as a new prognostic factor and therapeutic target for GC . Copyright © 2015 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

目的：研究慢病毒介导TGFβRⅡ基因对肝癌细胞MHCC97H体外增殖和侵袭能力的影响。方法：构建 TGFβRⅡ慢病毒载体 Lenti-TGFβRⅡ-puromycin-eGFP 并转染至人肝癌细胞 MHCC97H。 qPCR 和Western Blot检测TGFβRⅡ的表达。应用MTS和Transwell观察97H细胞增殖和侵袭能力的改变。结果：97H细胞成功转入 TGFβRⅡ，与对照组相比，qPCR 和 Western Blot 提示 TGFβRⅡ表达明显升高。 MTS 和Transwell实验结果显示在高表达TGFβRⅡ后其增殖和侵袭能力下降。结论：过表达TGFβRⅡ基因抑制肝癌细胞生长，提示该基因有望成为肝癌治疗的一个新方法。

Our previous proteomics study revealed that thioredoxin-interacting protein (TXNIP) was down-regulated by miR-373. However, little is known of the mechanism by which miR-373 decreases TXNIP to stimulate metastasis. In this study, we show that miR-373 promotes the epithelial-to-mesenchymal transition (EMT) in breast cancer. MiR-373 suppresses TXNIP by binding to the 3'UTR of TXNIP, which in turn, induces cancer cell EMT and metastasis. TXNIP co-expression, but not the TXNIP-3'UTR, reverses the enhancement of EMT, migration, invasion and metastasis induced by miR-373. MiR-373 stimulates EMT, migration and invasion through TXNIP-dependent reactive oxygen species (ROS) reduction. Mechanistically, miR-373 up-regulates and activates the HIF1 alpha-TWIST signaling axis via the TXNIP pathway. Consequently, TWIST induces miR-373 expression by binding to the promoter of the miR-371-373 cluster. Clinically, miR-373 is negatively associated with TXNIP and positively associated with HIF1 alpha and TWIST, and activation of the miR-373-TXNIP-HIF1 alpha-TWIST signaling axis is correlated with a worse outcome in patients with breast cancer. This signaling axis may be an independent prognostic factor for patients with breast cancer.

Hepatocellular carcinoma (HCC) is one of the common malignancies, which is highly metastatic and the third common cause of cancer deaths in the world. The invasion and metastasis of cancer cells is a multistep and complex process which is mainly initiated by extracellular matrix (ECM) degradation. Aberrant expression of microRNA has been investigated in HCC and shown to play essential roles during HCC progression. In the present study, we found that microRNA-324-5p (miR-324-5p) was downregulated in both HCC cell lines and tissues. Ectopic miR-324-5p led to the reduction of HCC cells invasive and metastatic capacity, whereas inhibition of miR-324-5p promoted the invasion of HCC cells. Matrix metalloproteinase 2 (MMP2) and MMP9, the major regulators of ECM degradation, were found to be downregulated by ectopic miR-324-5p, while upregulated by miR-324-5p inhibitor. E26 transformation-specific 1 (ETS1) and Specificity protein 1 (SP1), both of which could modulate MMP2 and MMP9 expression and activity, were presented as the direct targets of and downregulated by miR-324-5p. Downregulation of ETS1 and SP1 mediated the inhibitory function of miR-324-5p on HCC migration and invasion. Our study demonstrates that miR-324-5p suppresses hepatocellular carcinoma cell invasion and might provide new clues to invasive HCC therapy.

The loss of ITGA2 plays an important role in cancer metastasis in several solid cancers. However, the molecular mechanism of ITGA2 loss in primary cancers remains unclear. In this study, we found that a lower ITGA2 protein level was observed in breast cancers compared to adjacent non-cancerous breast tissues. Interestingly, the reduction degree of ITGA2 at the protein level was far more than that at the mRNA level. We further showed that the translation of ITGA2 mRNA was directly inhibited by miR-373 through binding to ITGA2-3’UTR. Silencing of ITGA2 detached cell-cell interactions, induced the deploymerization of stress fiber F-actin and stimulated cancer cell migration, similar to the effect of miR-373 over-expression. The co-expression of ITGA2, not ITGA2-3’UTR, could abrogate miR-373-induced cancer cell migration because that the expression of ITGA2-3’UTR was inhibited by co-transfected miR-373. ITGA2 protein level was inversely associated with miR-373 level in breast cancers (r = -0.663, P<0.001). 73.33% of breast cancer patients with high miR-373 and low ITGA2 expression exhibited the lymph node-positive metastases. Together, our results show that epigenetic silencing of ITGA2 by miR-373 stimulates breast cancer migration, and miR-373high/ITGA2low may be as a prognosis biomarker for breast cancer patients.