Annexin A2 silencing inhibits invasion, migration, and tumorigenic potential of hepatoma cells

AIM: To investigate the effects of Annexin A2 (ANXA2) silencing on invasion, migration, and tumorigenic potential of hepatoma cells. METHODS: Human hepatoma cell lines [HepG2, SMMC-7721, SMMC-7402, and MHCC97-H, a novel human hepatocellular carcinoma (HCC) cell line with high metastasis potential] and a normal hepatocyte cell line(LO2) were used in this study. The protein and mRNA expression levels of ANXA2 were analysed by western blotting and real-time polymerase chain reaction, re-spectively. The intracellular distribution profile of ANXA2 expression was determined by immunofluorescence and immunohistochemistry. Short hairpin RNA target-ing ANXA2 was designed and stably transfected into MHCC97-H cells. Cells were cultured for in vitro analy-ses or subcutaneously injected as xenografts in mice for in vivo analyses. Effects of ANXA2 silencing on cell growth were assessed by cell counting kit-8 (CCK-8) as-say (in vitro ) and tumour-growth assay (in vivo ), on cell cycling was assessed by flow cytometry and propidium iodide staining (in vitro ), and on invasion and migration potential were assessed by transwell assay and wound-healing assay, respectively (both in vitro ). RESULTS: The MHCC97-H cells, which are known to have high metastasis potential, showed the highest lev-el of ANXA2 expression among the four HCC cell types examined; compared to the LO2 cells, the MHCC97-H expression level was 8-times higher. The ANXA2 expres-sion was effectively inhibited (about 80%) by ANXA2-specific small hairpin RNA (shRNA). ANXA2 expression in the MHCC97-H cells was mainly localized to the cel-lular membrane and cytoplasm, and some localization was detected in the nucleus. Moreover, the proliferation of MHCC97-H cells was obviously suppressed by shR-NA-mediated ANXA2 silencing in vitro , and the tumour growth inhibition rate was 38.24% in vivo . The per-centage of MHCC97-H cells in S phase dramatically de-creased (to 27.76%) under ANXA2-silenced conditions. Furthermore, ANXA2-silenced MHCC97-H cells showed lower invasiveness (percentage of invading cells de-creased to 52.16%) and suppressed migratory capacity (migration distance decreased to 63.49%). It is also worth noting that shRNA-mediated silencing of ANXA2 in the MHCC97-H cells led to abnormal apoptosis. CONCLUSION: shRNA-mediated silencing of ANXA2suppresses the invasion, migration, and tumorigenic potential of hepatoma cells, and may represent a useful target of future molecular therapies.

CD133^+ gallbladder carcinoma cells exhibit self-renewal ability and tumorigenicity

AIM： To identify cancer stern cells （CSCs） in human gallbladder carcinomas （GBCs）. METHODS： Primary GBC cells were cultured under serum-free conditions to produce floating spheres. The stem-cell properties of the sphere-forming cells, including self-renewal, differentiation potential, chemoresistance and tumorigenicity, were determined in vitro or in vivo. Cell surface expression of CD133 was investigated in primary tumors and in spheroid cells using flow cytometry. The sphere-colony-formation ability and tumorigenicity of CD133＋ cells were assayed.floating spheroids were generated from primary GBC cells, and these sphere-forming cells could generate new progeny spheroids in serum-free media. Spheroid cells were differentiated under serum-containing conditions with downregulation of the stem cell markers Oct-4, Nanog, and nestin （P 〈 0.05）. The differentiated cells showed lower spheroid-colony-formation ability than the original spheroid cells （P 〈 0.05）. Spheroid ceils were more resistant to chemotherapeutic reagents than the congenetic adherent cells （P 〈 0.05）. Flow cytometry showed enriched CD133＋ population in sphereforming cells （P 〈 0.05）. CD133＋ cells possessed high colony-formation ability than the CD133 population （P 〈 0.01）. CD133＋ cells injected into nude mice revealed higher tumorigenicity than their antigen-negative counterparts （P 〈 0.05）. CONCLUSION： CD133 may be a cell surface marker for CSCs in GBC.

Overexpression of p42.3 promotes cell growth and tumorigenicity in hepatocellular carcinoma

AIM:To investigate the association of p42.3 expression with clinicopathological characteristics and the biological function of p42.3 in human hepatocellular carcinoma(HCC).METHODS:We used reverse transcription-polymerase chain reaction(RT-PCR),quantitative real-time RT-PCR and western blotting to detect p42.3 mRNA and protein expression in hepatic cell lines.We examined primary HCC samples and matched adjacent normal tissue by immunohistochemistry to investigate the correlation between p42.3 expression and clinicopathological features.HepG2 cells were transfected with a pIRES2EGFP-p42.3 expression vector to examine the function of the p42.3 gene.Transfected cells were analyzed for their viability and malignant transformation abilities by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay,colony formation assay,and tumorigenicity assay in nude mice.RESULTS:p42.3 is differentially expressed in primary HCC tumors and cell lines.Approximately 69.6%(96/138) of cells were p42.3-positive in hepatic tumor tissues,while 30.7%(35/114) were p42.3-positive in tumor-adjacent normal tissues.Clinicopathological characteristics of the HCC specimens revealed a significant correlation between p42.3 expression and tumor differentiation(P = 0.031).However,p42.3 positivity was not related to tumor tumor-node-metastasis classification,hepatitis B virus status,or hepatoma type.Regarding p42.3 overexpression in stably transfected HepG2 cells,we discovered significant enhancement of cancer cell growth and colony formation in vitro,and significantly enhanced tumorigenicity in nude mice.Western blot analysis of cell cycle proteins revealed that enhanced p42.3 levels promote upregulation of proliferating cell nuclear antigen,cyclin B1 and mitotic arrest deficient 2.CONCLUSION:p42.3 promotes tumorigenicity and tumor growth in HCC and may be a potential target for future clinical cancer therapeutics.

Tumorigenic bacteria in colorectal cancer:mechanisms and treatments

Colorectal cancer(CRC)is the third most common and the second most fatal cancer.In recent years,more attention has been directed toward the role of gut microbiota in the initiation and development of CRC.Some bacterial species,such as Fusobacterium nucleatum,Escherichia coli,Bacteroides fragilis,Enterococcus faecalis,and Salmonella sp.have been associated with CRC,based upon sequencing studies in CRC patients and functional studies in cell culture and animal models.These bacteria can cause host DNA damage by genotoxic substances,including colibactin secreted by pks+Escherichia coli,B.fragilis toxin(BFT)produced by Bacteroides fragilis,and typhoid toxin(TT)from Salmonella.These bacteria can also indirectly promote CRC by influencing host-signaling pathways,such as E-cadherin/β-catenin,TLR4/MYD88/NF-κB,and SMO/RAS/p38 MAPK.Moreover,some of these bacteria can contribute to CRC progression by helping tumor cells to evade the immune response by suppressing immune cell function,creating a proinflammatory environment,or influencing the autophagy process.Treatments with the classical antibacterial drugs,metronidazole or erythromycin,the antibacterial active ingredients,M13@Ag(electrostatically assembled from inorganic silver nanoparticles and the protein capsid of bacteriophage M13),berberine,and zerumbone,were found to inhibit tumorigenic bacteria to different degrees.In this review,we described progress in elucidating the tumorigenic mechanisms of several CRC-associated bacteria,as well as progress in developing effective antibacterial therapies.Specific bacteria have been shown to be active in the oncogenesis and progression of CRC,and some antibacterial compounds have shown therapeutic potential in bacteria-induced CRC.These bacteria may be useful as biomarkers or therapeutic targets for CRC.

Serum soluble suppression of tumorigenicity 2 as a novel inflammatory marker predicts the severity of acute pancreatitis

BACKGROUND Acute pancreatitis(AP)is an inflammatory disease in which the regulatory pathway is complex and not well understood.Soluble suppression of tumorigenicity 2(sST2)protein receptor functions as a decoy receptor for interleukin(IL)-33 to prevent IL-33/suppression of tumorigenicity 2L(ST2L)-pathwaymediated T helper(Th)2 immune responses.AIM To investigate the role of sST2 in AP.METHODS We assessed the association between sST2 and severity of AP in 123 patients enrolled in this study.The serum levels of sST2,C-reactive protein(CRP)and Th1-and Th2-related cytokines,including interferon(IFN)-γ,tumor necrosis factor(TNF)-α,IL-2,IL-4,IL-5 and IL-13,were measured by highly sensitive ELISA,and the severity of AP in patients was evaluated by the 2012 Atlanta Classification Criteria.RESULTS Serum sST2 levels were significantly increased in AP patients,and further,these levels were significantly elevated in severe AP(SAP)patients compared to moderately severe AP(MSAP)and mild AP(MAP)patients.Logistic regression showed sST2 was a predictor of SAP[odds ratio(OR):1.003(1.001–1.006),P=0.000].sST2 cutoff point was 1190 pg/mL,and sST2 above this cutoff was associated with SAP.sST2 was also a predictor of any organ failure and mortality during AP[OR:1.006(1.003–1.009),P=0.000,OR:1.002(1.001–1.004),P=0.012,respectively].Additionally,the Th1-related cytokines IFN-γand TNF-αin the SAP group were higher and the Th2-related cytokine IL-4 in the SAP group was significantly lower than those in MSAP and MAP groups.CONCLUSION sST2 may be used as a novel inflammatory marker in predicting AP severity and may regulate the function and differentiation of IL-33/ST2-mediated Th1 and Th2 Lymphocytes in AP homeostasis.

A meta-analysis of soluble suppression of tumorigenicity 2 （sST2） and clinical outcomes in pulmonary hypertension

Suppression of Tumorigenicity 2 （ST2） is a member of the interleukin （IL）-1 receptor family The ST2 receptor exists in two isoforms - ST2 ligand （ST2L） and soluble ST2 （sST2）.ST2L is a membrane receptor and sST2 is a trun- cated receptor which is soluble in the blood, allowing it to be detected in serum. IL-33 is a member of the IL-1 family of ligand and is the fimctional ligand of ST2L receptor. It binds to the ST2L, thereby mediating its immune function.

Differentiation and tumorigenicity of neural stem cells from human cord blood mesenchymal stem cells

BACKGROUND： Mesenchymal stem cells （MSCs） are capable of differentiating into a variety of tissues and exhibit low immunogenicity. OBJECTIVE： To investigate isolation and in vitro cultivation methods of human cord blood MSCs, to observe expression of neural stem cell （NSC） marker mRNA under induction, and to detect tumorigenicity in animals. DESIGN, TIME AND SETTING： A cell biological, in vitro trial and a randomized, controlled, in vivo experiment were performed at the Department of Neurology, Daping Hospital at the Third Military Medical University of Chinese PLA from August 2006 to May 2008. MATERIALS： Umbilical cord blood was collected from full-term-delivery fetus at the Department of Gynecology and Obstetrics of Daping Hospital, China. Eighteen BALB/C nu/nu nude mice were randomly assigned to three groups： back subcutaneous, cervical subcutaneous, and control, with 6 mice in each group. METHODS： Monocytes were isolated from heparinized human cord blood samples by density gradient centrifugation and then adherent cultivated in vitro to obtain MSC clones. After the cord blood MSCs were cultured for 7 days with nerve growth factor and retinoic acid to induce differentiation into NSCs, the cells （adjusted density of 1 × 10^7/mL） were prepared into cell suspension. In the back subcutaneous and cervical subcutaneous groups, nude mice were hypodermically injected with a 0.5-mL cell suspension into the back and cervical regions, respectively. In the control group, nude mice received a subcutaneous injection of 0.5 mL physiological saline into the back or cervical regions, respectively. MAIN OUTCOME MEASURES： Cellular morphology was observed by inverted microscopy, cultured cord blood MSCs were examined by flow cytometry, expression of nestin and musashi-1 mRNA was detected by reverse-transcriptase polymerase chain reaction prior to and after induction, and tumorigenicity following cord blood MSC transplantation was assayed by hematoxylin-eosin staining. RESULTS： Following adherent cultivation, the majority of cord blood monocytes became rhombic and strongly expressed CD29, but not CD34, CD1 la, or CD11 b. These results supported previously known characteristics of cord blood MSCs. Following differentiation induction, nestin and musashi-1 were expressed on the surface of NSCs, exhibiting strongest expression at 48 hours, and subsequently reducing expression. Cultured cord blood MSCs were not tumorigenic in the nude mice. Cellular morphology displayed no malignant changes between the control and subcutaneous groups. CONCLUSION： MSCs can be isolated from human cord blood, efficiently expanded under culture conditions, differentiated into NSCs following induction, and display no tumorigenicity in nude mice.

Genotoxic and tumorigenic pyrrolizidine alkaloids in Chinese herbal plants

Pyrrolizidine alkaloids are a class of hepatotoxic and tumorigenic compounds detected in Chinese herbal plants, contaminated foods, and dietary supplements. In this review, the sources, toxicity, genotoxicity, tumorigenicity, and the metabolic pathways, particular the activation pathways leading to hepatotoxicity and tumorigenicity, of pyrrolizidine alkaloids are briefly discussed, with a focus on the most recent important findings concerning the genotoxic mechanism by which riddelliine liver tumors. This mechanism involves the formation of 6,7-dihydro-7-hydroxy-1-hydroxymethyl-5H-pyrrolizine (DHP)-derived DNA adducts and may be general to most carcinogenic pyrrolizidine alkaloids.

Antisense Oligonucleotide Targeting TGF-β1 Abrogates Tumorigenicity of Rhabdomyosarcoma in vivo

OBJECTIVE Over-expression of transforming growth factor β1 （TGF-β1） has been observed in many advanced cancers. The present study was aimed at developing potential antisense oligonucleotides （ASONs） to repress TGF-β1 expression in rhabdomyosarcoma （RMS） RD cells, and to examine their effect on tumorigenicity of RD cells in vivo. METHODS ASONs targeting the region surrounding the start codon of TGF-β1 were synthesized and transferred into cells in the form of complexes with Lipofectamine 2000. The TGF-β1 protein was determined by immunofluorescence and ELISA. The cell viability and cell cycle were examined by MTT and flow cytometry. The RD cells, with or without TGF-β1ASON, in 50 μl of serum-free EMDM medium were injected subcutaneously into the right flank of nude mice. The tumors were then measured and weighed. RESULTS The ASON sequence targeting the first start site at bases 841-855 of the human TGF-β1 gene had the greatest effect on attenuating the expression of TGF-β1 （P 〈 0.05）. The ASONs induced a decrease in OD values after 6 d （P 〈 0.05）. Analysis of the cell cycle revealed that the ASON induced a significant decrease in cells in the S phase and an increase in cells in the G1 phase （P 〈 0,05）. In the nude mice model, the mean tumor volume, after 2 weeks of treatment with Lipofectamine or ASON, decreased to 88.5% or 55% respectively, compared to the control tumor size, resulting in a significant difference （P 〈 0.01）. CONCLUSION The sequence of the ASON, which targeted the start condon at the bases 841-855 of the human TGF-β1 gene, was demonstrated to be a useful agent for studying the regulation of TGF-β1 over-expression in RD cells, and has important therapeutic potential for suppressing the tumorigenicity of human RMS in vivo.

REDUCED TUMORIGENICITY OF METASTATIC HUMAN LUNG CANCER CELL SUBLINE（PGCL3） TRANSFECTED WITH hRARβ GENE

The recombinant PSG5-RARβ plasmid and the G418-resistant PSV2neo Plasmid ( 10 : 1) were cotransfected into PGCL3 cells by copreciprtation with calcium phosphate. The transfectants CR3 and CR4, which expressed the RARβ gene. were identified by Northern blot hybridization. The results showed that the in vitro growth and invasion of CR3 and CR4 were dramatically reduced compared to the control-transfected cell (CSV1). Furthermore, the colony-forming abilities in soft agar and the tumorigenicrty in nude mice of CR3 and CR4 were abrogated. Our results suggests that RARβ functions not only as a receptor mediating the RA action, but also as a suppressor in lung tumorigenesis.

Inhibition of cervical cancer cell proliferation and cervical tumorigenicity caused by farnesoid X receptor activation or over-expression is related to CDKN2A-p14^(ARF)-MDM2-p53 pathway

OBJECTIVE Cervical cancer is the third most malignant tumor in the world.Farnesoid X receptor(FXR) is a member of nuclear receptor superfamily.It is highly expressed in liver,kidney and small intestine,while it showed low expression level in other tissues.It not only plays an important role in the metabolism of bile acids and sugars,but also in the production of chronic inflammation in the early stage of cancer,the proliferation and migration of tumor.Compared with the normal tissue,the expression of FXR in most tumor tissues decreased.But there is no correlation between cervical cancer and FXR.So we aimed to find out the relationship between FXR and cervical cancer.METHODS A clinical study using q PCR,western blot and immunohistochemistry detected the expression of FXR in tumor tissues and normal tissues of clinical patients.FXR was activated by agonists or over-expressed by lentivirus.MTT,clone formation and flow cytometry were used to detect the relationship between FXR and proliferation of cervical cell lines.Tumor growth ability of FXR was detected by nude mice tumorigenicity.The interaction between FXR and CDKN2A-p14^(ARF)-MDM2-p53 pathway was detected by q PCR,Western blot and immunohistochemistry.RESULTS FXR was decreased in cancer tissues compared to normal control.Activation of FXR by agonist or constitutively-over-expression of FXR inhibited cervical cell proliferation.Over-expressed FXR attenuated Caski,Hela and Siha xenograft tumor growth in nude mice compared with control.Over-expression of FXR caused G1 cell-cycle arresting and up-regulated CDKN2A-p14^(ARF)-MDM2-p53 pathway.CONCLUSION FXR inhibits cervical cancer cell proliferation and cervical tumorigenicity which is related to CDKN2A-p14^(ARF)-MDM2-p53 pathway.Activation or overexpression of FXR may be a potential target for the treatment of cervical cancer.

Further Report on Carcinogenesis or Tumorigenicity ofMDCK Canine Kidney Cell(CKC) Lines and Analysis ofTheir Chromosome Karyotypes

Using Hela cell cultures as positive control and primary canine kidney cell (CKC) or feline kidney cell (FKC) cultures purified in vitro on passage 3 as negative control, the tumorigenicity of Madin-Darby canine kidney (MDCK) cells was tested in >273 nude mice, and colony formation in soft agarose and haemag-glutination under different concentration of plant lectins of these cells were carried out at the same time. Subsequently, very low tumorigenicity strains of MDCK line were successfully selected; these were evaluated for the production of canine or feline combination viral vaccines, free of infectious agents, and of known cytoge-netic and tumorigenic. It is thus evident that MDCK cell of M, JB, JC, WB or H strain can be approved as substrate for the preparation of attenuated viral vaccines, but MDCK cell of YA, YB and KA strains can not be approved as substrate for the preparation of attenuated viral vaccines. The heritable character of these cell sub-lines is comparatively stable, and shows little significant difference between passages.

Identification of tumorigenic risk genes in human placenta-derived mesenchymal stem cells treated with 3-methylcholanthrene

Mesenchymal stem cells(MSCs)capable of tumour topotaxis have been served as cellular vehicles to deliver anti-tumour agents.As cellular components of the tumour microenvironment,MSCs also affect tumour progression.However,the tumour transformation-related genes of MSCs remain unclear since either tumorigenic or tumour suppressor effects within these cells have been researched.Hence,we aimed to identify potential biomarkers indicative of tumorigenic risk by RNA-seq analysis of human placenta tissue-derived MSCs(hPTMSCs)exposed to the carcinogenic agent,3-methylcholanthrene(3-MC).Twenty-nine tumour transformation-related genes and three pluripotency-related genes were appraised as differentially expressed genes(DEGs)in hPTMSCs.Overexpression of sfrp1 led to reduced cell viability,migration,and colony formation in A549.In contrast,the overexpression of ptgs2 exerted the opposite effect.These results indicate that A549 cells with high ptgs2 expression but low sfrp1 expression may have a more potential tumorigenic capacity.Taken together,this study suggests that ptgs2 and sfrp1 may be tumorigenic risk genes.

In vitro proliferation and in vivo tumorigenicity of IL-2 gene and IL-3 gene co-transfected leukemia cells

<Abstract>In vitro proliferation and in vivo tumorigenicity of IL-2 and/or IL-3 gene transfected FBL-3erythroleukemia cells were observed to investigate the anti-tumor effect of tumor vaccine. Methods: Leukemiacells were trans fected with IL-2 and/or IL-3 adenovlrus vector. The cytokine expressions were assayed, and the growth characteristics of the transfected FBL-3 cells were studied. Results: High levels of secreted IL-2 and IL-3remained for one week after transfection, and the trans fected leukemia cells became unchanged in growth in vitro and showed weak tumorigenicity in vlvo. The tumorigenicity of FBL-3 cells decreased more significantly when FBL-3 cells were transfected with both IL-2 gene and IL-3 gene than when FBL-3 cells were tran fected with IL-2or IL-3 gene only. The tumor growth was significantly delayed and survival time of the trans fected FBL-3 inoculat ed mice was significantly prolonged. Conclusion: The inhibition of tumor growth is most likely dependent on immune response induced by

Paradoxical role of interleukin-33/suppressor of tumorigenicity 2 in colorectal carcinogenesis: Progress and therapeutic potential

Colorectal cancer(CRC)is presently the second most prevalent global mortalityinducing cancer.CRC carcinogenesis is a multifactorial process involving internal genetic mutations and the external environment.In addition,non-neoplastic cell activities within tumor microenvironments for CRC development have been established.However,interleukin(IL)-33,secreted by such cell types,plays a pivotal role in cancer progression due to interaction with cellular constituents within the tumor-inflammation microenvironment.IL-33 belongs to the IL-1 cytokine family and acts as binding attachments for the suppressor of tumorigenicity(ST)2 receptor.Therefore,how to coordinate tumor microenvironment,design and optimize treatment strategies suitable for CRC,based on IL-33/ST2 signal is a challenge.Even though it has established influences upon immunitylinked conditions,IL-33 effects on CRC progression and prevention and related mechanisms are still controversial.Our review depicts controversial activities for IL-33/ST2 within carcinogenesis and cancer prevention.Moreover,IL-33/ST2 signaling is a potential therapeutic target for CRC.

Glypican 4 down-regulation in pluripotent stem cells as a potential strategy to improve differentiation and to impair tumorigenicity of cell transplants

Recent advances in stem cell technologies have opened new avenues for the treatment of a number of diseases still lacking effective therapeutic options.Cell transplantation has emerged as among the most promising clinical intervention for disorders such as injuries,diabetes,liver diseases, neurodegeneration and heart failure （Lee et al., 2013; Forbes and Rosenthal, 2014; Tabar and Studer, 2014）.

An RNA-seq-based Gene Expression Profiling of Radiation-induced Tumorigenic Mammary Epithelial Cells

Immortality and tumorigenicity are two distinct characteristics of cancers. Immortalization has been suggested to precede tumorigenesis. To understand the molecular mechanisms of tumorigenicity and cancer progression in mammary epithelium, we established a tumori- genic cell model by means of heavy-ion radiation of an immortal cell model, which was created by overexpressing the human telomerase reverse transcriptase （hTERT） in normal human mammary epithelial cells. We examined the expression profile of this tumorigenic cell line （T hMEC） using the hTERT-overexpressing immortal cell line （IhMEC） as a control. In-depth RNA-seq data was generated by using the next-generation sequencing （NGS） platform （Life Technologies SOLID3）. We found that house-keeping （HK） and tissue-spe- cific （TS） genes were differentially regulated during the tumorigenic process. HK genes tended to be activated while TS genes tended to be repressed. In addition, the HK genes and TS genes tended to contribute differentially to the variation of gene expression at different RPKM （gene expression in reads per exon kilobase per million mapped sequence reads） levels. Based on transcriptome analysis of the two cell lines, we defined 7053 differentially-expressed genes （DEGs） between immortality and tumorigenicity. Differential expression of 20 manually-selected genes was further validated using qRT-PCR. Our observations may help to further our understanding of cellular mechanism（s） in the transition from immortalization to tumorigenesis.

TGFβ signaling hyperactivation-induced tumorigenicity during the derivation of neural progenitors from mouse ESCs

Clinical therapies of pluripotent stem cells （PSCs）-based transplantation have been hindered by frequent development of terato- mas or tumors in animal models and clinical patients. Therefore, clarifying the mechanism of carcinogenesis in stem cell therapy is of great importance for reducing the risk of tumorigenicity. Here we differentiate Oct4-GFP mouse embryonic stem cells （mESCs） into neural progenitor cells （NPCs） and find that a minority of Oct4＋ cells are continuously sustained at Oct4＋ state. These cells can be enriched and proliferated in a standard ESC medium. Interestingly, the differentiation potential of these enriched cells is tightly restricted with much higher tumorigenic activity, which are thus defined as differentiation-resistant ESCs （DR-ESCs）. Transcriptomic and epigenomic analyses show that DR-ESCs are characterized by primordial germ cell-like gene sig- natures （Dazl, Rec8, Stro8, BUmp1, etc.） and specific epigenetic patterns distinct from mESCs. Moreover, the DR-ESCs possess germ cell potential to generate Sycp3＋ haploid cells and are able to reside in sperm-free spermaduct induced by busulfan. Finally, we find that TGFβ signaling is overactivated in DR-ESCs, and inhibition of TGFβ signaling eliminates the tumorigenicity of mESC-derived NPCs by inducing the full differentiation of DR-ESCs. These data demonstrate that these TGFβ-hyperactivated germ ceU-like DR-ESCs are the main contributor for the tumorigenicity of ESCs-derived target cell therapy and that inhibition of TGFβ signaling in ESC-derived NPC transplantation could drastically reduce the risk of tumor development. Keywords： embryonic stem cells, differentiation-resistant ESCs, tumorigenicity, germ cell, TGFβ signaling

The unsulfated extracellular N-terminus of vGPCR reduces the tumorigenicity of hGRO-α in nude mice

The Kaposi's Sarcoma-associated Herpesvirus (KSHV)-encoded G-protein coupled receptor (vGPCR) is an oncoprotein that is implicated in KSHV-associated malignancies. We previously revealed vGPCR incorporates sulfate groups within its extracellular N-terminal tyrosine residues (Y26 and Y28) and that this tyrosine sulfation is crucial for its tumorigenicity in nude mice. hGRO-binds vGPCR in a sulfotyrosine-dependent manner and promotes its tumorigenicity through autocrine signaling. Interestingly, an unsulfated vGPCR mutant (yydd-vGPCR) attenuated the tumor growth triggered by hGRO-α . In this study, the extracellular N-terminus of vGPCR (wt-vGN) and an unsulfated vGPCR mutant (yydd-vGN) were individually secreted, expressed and purified. A radioactive labeling assay demonstrated that wt-vGN but not yydd-vGN incorporated [ 35 S]-sulfate. In nude mice, NIH3T3 cells expressing yydd-vGN but not wt-vGN could significantly inhibit the tumor growth triggered by hGRO-α . All our data support the conclusion that the unsulfated extracellular N-terminus of vGPCR reduces the tumorigenicity of hGRO-α .

Impaired dNKAP function drives genome instability and tumorigenic growth in Drosophila epithelia

Mutations or dysregulated expression of NF-kappaB-activating protein(NKAP)family genes have been found in human cancers.How NKAP family gene mutations promote tumor initiation and progression remains to be determined.Here,we characterized dNKAP,the Drosophila homolog of NKAP,and showed that impaired dNKAP function causes genome instability and tumorigenic growth in a Drosophila epithelial tumor model.dNKAP-knockdown wing imaginal discs exhibit tumorigenic characteristics,including tissue overgrowth,cell-invasive behavior,abnormal cell polarity,and cell adhesion defects.dNKAP knockdown causes both R-loop accumulation and DNA damage,indicating the disruption of genome integrity.Further analysis showed that dNKAP knockdown induces c-Jun N-terminal kinase(JNK)-dependent apoptosis and causes aberrant cell proliferation in distinct cell populations.Activation of the Notch and JAK/STAT signaling pathways contributes to the tumorigenic growth of dNKAP-knockdown tissues.Furthermore,JNK signaling is essential for dNKAP depletion-mediated cell invasion.Transcriptome analysis of dNKAP-knockdown tissues confirmed the misregulation of signaling pathways involved in promoting tumorigenesis and revealed abnormal regulation of metabolic pathways.dNKAP knockdown and oncogenic Ras,Notch,or Yki mutations show synergies in driving tumorigenesis,further supporting the tumor-suppressive role of dNKAP.In summary,this study demonstrates that dNKAP plays a tumor-suppressive role by preventing genome instability in Drosophila epithelia and thus provides novel insights into the roles of human NKAP family genes in tumor initiation and progression.