A Complex Interplay between Notch Effectors and ß-Catenin Signaling in Morular Differentiation of Endometrial Carcinoma Cells.

Notch signaling contributes to tissue development and homeostasis, but little is known about its role in morular differentiation of endometrial carcinoma (Em Ca) cells. The current study focused on crosstalk between Notch and ß-catenin signaling in Em Ca with morules. Promoters of hairy and enhancer of split 1 (Hes1) and mastermind-like 2 (MAML2) were activated by Notch intracellular domain 1 but not ß-catenin, and a positive feedback loop between Hes1 and MAML2 was observed. Immunoreactivities for nuclear ß-catenin, Hes1, and MAML2, as well as the interaction between ß-catenin and Hes1 or MAML2, were significantly higher in morular lesions compared with surrounding carcinoma in Em Ca. Inhibition of glycogen synthase kinase-3ß (GSK-3ß) increased expression of total nuclear and cytoplasmic GSK-3ß and its phosphorylated forms, as well as Notch intracellular domain 1, Hes1, and active ß-catenin. GSK-3ß inhibition also decreased proliferation and migration, consistent with the response of cells stably overexpressing Hes1. Finally, the nuclear/cytoplasmic GSK-3ß score was significantly higher in morules compared with surrounding carcinoma in Em Ca, and it was positively correlated with nuclear ß-catenin, Hes1, and MAML2 scores. This complex interplay between Notch effectors and ß-catenin signaling through GSK-3ß inhibition contributes to the establishment and maintenance of ß-catenin-mediated morular differentiation, which is, in turn, associated with reduced proliferation and inhibition of migration in Em Ca.

Nucleobindin-2 Mediates Transforming Growth Factor-ß1-Driven Phenotypes in Zinc Finger E-Box Binding Homeobox 1-High Uterine Carcinosarcoma.

Epithelial-mesenchymal transition is a hallmark of uterine carcinosarcoma (UCS). Here, shotgun proteomics analysis used to identify biomarkers associated with blebbistatin-mediated epithelial-mesenchymal transition in UCS indicated up-regulation of nucleobindin-2 (NUCB2) in endometrial carcinoma (Em Ca) cells. Expression of N-cadherin, Snail, Slug, and ZEB1 was reduced in NUCB2 knockout Em Ca cells, whereas ZEB1, Twist1, and vimentin were up-regulated in NUCB2-overexpressing Em Ca cells. NUCB2 knockout reduced cell proliferation and migration, whereas NUCB2 overexpression had the opposite effect. Treatment of Em Ca cells with transforming growth factor (TGF)-ß1 dramatically altered morphology toward a fibroblastic appearance; concomitantly, expression of NUCB2 and ZEB1 increased. The NUCB2 promoter was also activated by transfection of Smad2. In UCS tissues, NUCB2 expression was significantly higher in sarcomatous compared with carcinomatous components, which was consistent with increased TGF-ß1 mRNA expression in stromal and sarcomatous components compared with carcinomatous components. In addition, NUCB2 score correlated positively with ZEB1 and vimentin scores, whereas ZEB1 score correlated positively with Slug and vimentin scores and inversely with the E-cadherin score. Collectively, these data indicate that TGF-ß-dependent up-regulation of NUCB2 and ZEB1 contributes to the phenotypic characteristics of sarcomatous components in UCS.

Anaplastic lymphoma kinase overexpression enhances aggressive phenotypic characteristics of endometrial carcinoma.

BACKGROUND: Although anaplastic lymphoma kinase (ALK) is overexpressed in several primary solid tumor types, its role in endometrial carcinoma (Em Ca) remains unclear. METHODS: We evaluated expression of ALK and its related molecules in clinical samples consisting of 168 Em Ca tissues. We also used Em Ca cell lines to evaluate the functional role of ALK. RESULTS: Cytoplasmic ALK immunoreactivity in the absence of chromosomal rearrangement was positively correlated with ALK mRNA expression, and was significantly higher in Grade (G) 3 Em Ca than in G1 or G2 tumors. ALK immunoreactivity was also significantly associated with expression of cancer stem cell (CSC)-related molecules (cytoplasmic CD133, ALDH1, Sox2) and neuroendocrine markers (CD56 and synaptophysin). Although the proliferative index was significantly higher in ALK-positive Em Ca when compared to ALK- negative malignancies, there was no association between ALK expression and other clinicopathological factors in this disease. In Em Ca cell lines, full-length ALK overexpression increased proliferation, decreased susceptibility to apoptosis, enhanced cancer stem cell features, and accelerated cell mobility, whereas these phenotypes were abrogated in ALK-knockdown cells. Finally, patients with tumors harboring either wild-type ALK or high ALK mRNA expression had a poorer prognosis than those with either mutant ALK or low ALK mRNA expression. CONCLUSION: Full-length ALK overexpression occurs in a subset of Em Ca, particularly in G3 tumors, and contributes to the establishment and maintenance of aggressive phenotypic characteristics through modulation of several biological processes.

Anaplastic Lymphoma Kinase Overexpression Is Associated with Aggressive Phenotypic Characteristics of Ovarian High-Grade Serous Carcinoma.

Deregulated full-length anaplastic lymphoma kinase (ALK) overexpression has been found in some primary solid tumors, but little is known about its role in ovarian high-grade serous carcinoma (HGSC). The current study focused on the functional roles of ALK in HGSC. Cytoplasmic ALK immunoreactivity without chromosomal rearrangement and gene mutations was significantly higher in HGSC compared with non-HGSC-type ovarian carcinomas, and was significantly associated with several unfavorable clinicopathologic factors and poor prognosis. HGSC cell lines stably overexpressing ALK exhibited increased cell proliferation, enhanced cancer stem cell features, and accelerated cell mobility, whereas these phenotypes were abrogated in ALK-knockdown cells. Expression of the nervous system-associated gene, ELAVL3, and the corresponding protein (commonly known as HuC) was significantly increased in cells overexpressing ALK. Expression of SRY-box transcription factor (Sox)2 and Sox3 (genes associated with the neural progenitor population) increased in ALK-overexpressing but not ALK-knockdown cells. Furthermore, overexpression of Sox2 or Sox3 enhanced both ALK and ELAVL3 promoter activities, suggesting the existence of ALK/Sox/HuC signaling loops. Finally, ALK overexpression was attributed to increased expression of neuroendocrine markers, including synaptophysin, CD56, and B-cell lymphoma 2, in HGSC tissues. These findings suggest that overexpression of full-length ALK may influence the biological behavior of HGSC through cooperation with ELAVL3 and Sox factors, leading to the establishment and maintenance of the aggressive phenotypic characteristics of HGSC.

Functional interaction between S100A1 and MDM2 may modulate p53 signaling in normal and malignant endometrial cells.

BACKGROUND: S100A1 expression is deregulated in a variety of human malignancies, but its role in normal and malignant endometrial cells is unclear. METHODS: We used endometrial carcinoma (Em Ca) cell lines to evaluate the physical and functional interaction of S100A1 with p53 and its negative regulator, mouse double minute 2 (MDM2). We also evaluated the expression of S100A1, p53, and MDM2 in clinical samples consisting of 89 normal endometrial and 189 Em Ca tissues. RESULTS: S100A1 interacted with MDM2 but not p53 in Em Ca cell lines. Treatment of cells stably overexpressing S100A1 with Nutlin-3A, an inhibitor of the p53/MDM2 interaction, increased expression of p53-target genes including p21waf1 and BAX. S100A1 overexpression enhanced cellular migration, but also sensitized cells to the antiproliferative and proapoptotic effects of Adriamycin, a genotoxic agent; these phenotypes were abrogated when S100A1 was knocked down using shRNA. In clinical samples from normal endometrium, S100A1 expression was significantly higher in endometrial glandular cells of the middle/late secretory and menstrual stages when compared to cells in the proliferative phases; high S100A1 was also positively correlated with expression of MDM2 and p21waf1 and apoptotic status, and inversely correlated with Ki-67 scores. However, such correlations were absent in Em Ca tissues. CONCLUSION: The interaction between S100A1 and MDM2 may modulate proliferation, susceptibility to apoptosis, and migration through alterations in p53 signaling in normal- but not malignant-endometrial cells.

A functional role of S100A4/non-muscle myosin IIA axis for pro-tumorigenic vascular functions in glioblastoma.

BACKGROUND: Glioblastoma (GBM) is the most aggressive form of brain tumor and has vascular-rich features. The S100A4/non-muscle myosin IIA (NMIIA) axis contributes to aggressive phenotypes in a variety of human malignancies, but little is known about its involvement in GBM tumorigenesis. Herein, we examined the role of the S100A4/NMIIA axis during tumor progression and vasculogenesis in GBM. METHODS: We performed immunohistochemistry for S100A4, NMIIA, and two hypoxic markers, hypoxia-inducible factor-1α (HIF-1α) and carbonic anhydrase 9 (CA9), in samples from 94 GBM cases. The functional impact of S100A4 knockdown and hypoxia were also assessed using a GBM cell line. RESULTS: In clinical GBM samples, overexpression of S100A4 and NMIIA was observed in both non-pseudopalisading (Ps) and Ps (-associated) perinecrotic lesions, consistent with stabilization of HIF-1α and CA9. CD34(+) microvascular densities (MVDs) and the interaction of S100A4 and NMIIA were significantly higher in non-Ps perinecrotic lesions compared to those in Ps perinecrotic areas. In non-Ps perinecrotic lesions, S100A4(+)/HIF-1α(-) GBM cells were recruited to the surface of preexisting host vessels in the vascular-rich areas. Elevated vascular endothelial growth factor A (VEGFA) mRNA expression was found in S100A4(+)/HIF-1α(+) GBM cells adjacent to the vascular-rich areas. In addition, GBM patients with high S100A4 protein expression had significantly worse OS and PFS than did patients with low S100A4 expression. Knockdown of S100A4 in the GBM cell line KS-1 decreased migration capability, concomitant with decreased Slug expression; the opposite effects were elicited by blebbistatin-dependent inhibition of NMIIA. CONCLUSION: S100A4(+)/HIF-1α(-) GBM cells are recruited to (and migrate along) preexisting vessels through inhibition of NMIIA activity. This is likely stimulated by extracellular VEGF that is released by S100A4(+)/HIF-1α(+) tumor cells in non-Ps perinecrotic lesions. In turn, these events engender tumor progression via acceleration of pro-tumorigenic vascular functions. Video abstract.

PTEN overexpression and nuclear ß-catenin stabilization promote morular differentiation through induction of epithelial-mesenchymal transition and cancer stem cell-like properties in endometrial carcinoma.

BACKGROUND: Although a lack of functional PTEN contributes to tumorigenesis in a wide spectrum of human malignancies, little is known about the functional role of its overexpression in the tumors. The current study focused on PTEN overexpression in endometrial carcinoma (Em Ca). METHODS: The functional impact of PTEN overexpression was assessed by Em Ca cell lines. Immunohistochemical analyses were also conducted using 38 Em Ca with morular lesions. RESULTS: Em Ca cell lines stably overexpressing PTEN (H6-PTEN) exhibited epithelial-mesenchymal transition (EMT)-like features, probably through ß-catenin/Slug-meditated suppression of E-cadherin. PTEN overexpression also inhibited cell proliferation, accelerated cellular senescence, increased apoptotic features, and enhanced migration capability. Moreover, H6-PTEN cells exhibited cancer stem cell (CSC)-like properties, along with high expression of aldehyde dehydrogenase 1 and CD44s, a large ALDH 1high population, enriched spheroid formation, and ß-catenin-mediated upregulation of cyclin D2, which is required for persistent CSC growth. In clinical samples, immunoreactivities for PTEN, as well as CSC-related molecules, were significantly higher in morular lesions as compared to the surrounding carcinomas. PTEN score was positively correlated with expression of nuclear ß-catenin, cytoplasmic CD133, and CD44v6, and negatively with cell proliferation. Finally, estrogen receptor-α (ERα)-dependent expression of Ezrin-radixin-moesin-binding phophoprotein-50 (EBP50), a multifunctional scaffolding protein, acts as a negative regulator of morular formation by Em Ca cells through interacting with PTEN and ß-catenin. CONCLUSION: In the abscess of ERα/EBP50 expression, PTEN overexpression and nuclear ß-catenin stabilization promote the establishment and maintenance of morular phenotype associated with EMT/CSC-like features in Em Ca cells. Video Abstract.

Cytoplasmic EBP50 and elevated PARP1 are unfavorable prognostic factors in ovarian clear cell carcinoma.

Patients with ovarian clear cell carcinoma (OCCC) experience frequent recurrence, which is most likely due to chemoresistance. We used shotgun proteomics analysis and identified upregulation of ezrin-binding phosphoprotein 50 (EBP50) in recurrent OCCC samples. Cytoplasmic and/or nuclear (Cyt/N), but not membranous, EBP50 immunoreactivity was significantly higher in recurrent OCCC as compared with that of primary tumors. OCCC cells expressing cytoplasmic EBP50 were significantly less susceptible to cisplatin (CDDP)-induced apoptosis compared with cells expressing membranous EBP50. Abrogation of resistance following knockdown of cytoplasmic EBP50 was accompanied by decreased XIAP and BCL2, increased BAX and increased caspase-3 cleavage. We found that poly (ADP-ribose) polymerase1 (PARP1), which is involved in DNA damage detection and repair, binds to EBP50 through its PDZ1 domain. CDDP treatment of cells expressing cytoplasmic (but not membranous) EBP50 increased nuclear PARP1 expression, whereas knockdown of EBP50 cells decreased PARP1 expression and activity following CDDP treatment. Finally, OCCC patients with a combination of Cyt/N EBP50 and high PARP1 score had worst the prognosis for overall and progression-free survival. Together, our data suggest that cytoplasmic EBP50 inhibits apoptosis and promotes OCCC survival through stabilization of PARP1 activity and modulation of the XIAP/BCL2/BAX axis. This may increase the likelihood of tumor recurrence, and we therefore suggest a combined analysis for EBP50 and PARP1 may have great utility in OCCC prediction and prognosis.

S100A4/Nonmuscle Myosin IIA/p53 Axis Contributes to Aggressive Features in Ovarian High-Grade Serous Carcinoma.

S100A4 is a small calcium-binding protein that exerts its biological functions by interacting with nonmuscle myosin IIA (NMIIA) and p53. Although S100A4 promotes metastasis in several tumors, little is known about its involvement in the progression of ovarian high-grade serous carcinomas (HGSCs). Herein, we focused on functional roles of the S100A4/NMIIA/p53 axis in these tumors. In HGSC cell lines harboring mutant p53, knockdown (KD) of S100A4 reduced the expression of several epithelial-mesenchymal transition/cancer stem cell markers and the ALDH1high population, consistent with an inhibition of stemness features. S100A4-KD also increased apoptosis, decreased cell proliferation, and accelerated cell mobility. This was accompanied by increased Snail expression, which, in turn, was likely due to loss of p53 function. In contrast, specific inhibition of NMIIA by blebbistatin induced phenotypes that-with the exception of cell proliferation and mobility-were opposite to those observed in S100A4-KD cells. In clinical samples, cytoplasmic and/or nuclear interactions between S100A4, NMIIA, and mutant p53 were observed. In addition, high expression of S100A4, but not NMIIA or p53, was a significant and independent unfavorable prognostic factor in HGSC patients. These findings suggest that, via its interaction with NMIIA and p53, overexpressed S100A4 may induce epithelial-mesenchymal transition/cancer stem cell properties in HGSC and elicit several other tumor-associated phenotypes.

S100A4/non-muscle myosin II signaling regulates epithelial-mesenchymal transition and stemness in uterine carcinosarcoma.

Uterine carcinosarcoma (UCS) represents a true example of cancer associated with epithelial-mesenchymal transition (EMT), which exhibits cancer stem cell (CSC)-like traits. Although S100A4 is an inducer of EMT, little is known about its involvement in UCS tumorigenesis. Herein, we focused on the functional role of S100A4 during development of UCS. Expression of S100A4 and molecules associated with its function were also examined in 35 UCS cases. In endometrial carcinoma cell lines, S100A4 promoter activity and mRNA levels were significantly increased by the transfection of NF-κB/p65, independent of a putative κB-binding site in the promoter. Cells stably overexpressing S100A4 showed enhancement of CSC properties, along with decreased cell proliferation and acceleration of cell migration. These phenotypes were abrogated in S100A4-knockdown cells. A combination of S100A4 antibody-mediated co-immunoprecipitation and shotgun proteomics analysis revealed that S100A4 strongly interacted with non-muscle myosin II (NMII) heavy chains, including myosin 9 and myosin 14. Specific inhibition of NMII by blebbistatin phenocopied S100A4 overexpression and induced a fibroblast-like morphology. In clinical samples, S100A4 score was significantly higher in sarcomatous as compared with carcinomatous components of UCS, and was positively correlated with ALDH1, Slug, and vimentin scores, and inversely with Ki-67 labeling indices. These findings suggest that an S100A4/NMII-related signaling cascade may contribute to the establishment and maintenance of EMT/CSC properties, along with changes in cell proliferation and migration capability. These events may be initiated in carcinomatous components in UCS and lead to divergent sarcomatous differentiation.

Upregulation of fibronectin following loss of p53 function is a poor prognostic factor in ovarian carcinoma with a unique immunophenotype.

BACKGROUND: We previously demonstrated that ovarian high grade serous carcinomas (OHGSeCa) and ovarian clear cell carcinomas (OCCCa) with an HNF-1ß+/p53+/ARID1A+ immunophenotype were associated with the worst unfavorable prognosis. To clarify the molecular mechanisms underlying this finding, we focused on alterations in the p53 signaling pathway in these tumors. METHODS: Changes in cell phenotype and function following knockdown of wild-type p53 (p53-KD) were assessed using OCCCa cells expressing endogenous HNF-1ß and ARID1A. The prognostic significance of molecules that were deregulated following p53-KD was also examined using 129 OCCCa/OHGSeCa cases. RESULTS: p53-KD cells had increased expression of Snail, phospho-Akt (pAkt), and pGSK3ß, and decreased E-cadherin expression, leading to epithelial-mesenchymal transition (EMT)/cancer stem cell (CSC) features. The cells also exhibited acceleration of cell motility and inhibition of cell proliferation and apoptosis. Next generation sequencing revealed that fibronectin (FN) expression was significantly increased in the p53 KD-cells, in line with our observation that wild-type p53 (but not mutant p53) repressed FN1 promoter activity. In addition, treatment of OCCCa cells with FN significantly increased cell migration capacity and decreased cell proliferation rate, independent of induction of EMT features. In clinical samples, FN/p53 scores were significantly higher in OCCCa/OHGSeCa with the HNF-1ß+/p53+/ARID1A+ immunophenotype when compared to others. Moreover, high FN/high p53 expression was associated with the worst overall survival and progression-free survival in OCCCa/OHGSeCa patients. CONCLUSION: These findings suggest that upregulation of FN following loss of p53 function may impact the biological behavior of OCCCa/OHGSeCa, particularly in tumors with an HNF-1ß+/p53+/ARID1A+ immunophenotype, through alterations in cell mobility and cell proliferation. The accompanying induction of EMT/CSC properties and inhibition of apoptosis due to p53 abnormalities also contribute to the establishment and maintenance of tumor phenotypic characteristics. Video Abstract.

Nodal induces apoptosis and inhibits proliferation in ovarian endometriosis-clear cell carcinoma lesions.

BACKGROUND: Expression of Nodal, a member of the TGF-ß superfamily, is commonly absent in differentiated tissues, while its re-expression occurs in a variety of human malignancy. However, little is known about its involvement in ovarian tumorigenesis. Herein, we focused on the functional roles of Nodal in ovarian endometriosis-carcinoma lesions. METHODS: Regulation and function of Nodal and its associated molecules, including Smad2, GSK-3ß, and several cell kinetics-related molecules, were assessed using clinical samples consisting of 108 ovarian carcinomas and 33 endometriotic lesions, as well as ES-2 (ovarian clear cell carcinoma; OCCCa) and Ishikawa (endometrial carcinoma) cell lines. RESULTS: Nodal expression was significantly higher in endometriosis and OCCCa lesions as compared to that of non-OCCCas, with positive correlations to phosphorylated forms of both Smad2 (pSmad2) and GSK-3ß. When compared to endometriotic lesions, the expression of Nodal and pSmad2 was significantly decreased in OCCCa. Treatment of Ishikawa cells with TGF-ß1 resulted in transcriptional upregulation of Nodal, along with increased pSmad2 expression, while inhibition of GSK-3ß also induced an increase in Nodal expression at the posttranslational level. Both ES-2 and Ishikawa cells stably overexpressing Nodal had increased susceptibility to apoptosis in response to treatment with cisplatin and doxorubicin, respectively, together with higher cleaved caspase-3 expression and decreased Bcl2/Bax ratio. Moreover, the stable Nodal-overexpressing cells showed reduced cell proliferation, along with increased expression of p27kip1 and p21waf1. In clinical samples, a significantly higher number of apoptotic cells and lower Ki-67 labeling indices were observed in Nodal-positive as compared to Nodal-negative OCCCa. CONCLUSIONS: These findings suggest that Nodal is a multifunctional cytokine involved in the modulation of cell kinetics in ovarian endometriosis-OCCCa lesions.

TGF-ß-mediated LEFTY/Akt/GSK-3ß/Snail axis modulates epithelial-mesenchymal transition and cancer stem cell properties in ovarian clear cell carcinomas.

Advanced ovarian clear cell carcinoma (OCCCa) shows poor prognosis with chemoresistance, which is associated with epithelial-mesenchymal transition (EMT)/cancer stem cell (CSC) features. The left-right determination factor (LEFTY), a novel member of the TGF-ß superfamily, is a marker of stemness. Here we focused on the functional roles of LEFTY in OCCCas. OCCCa cell lines that were cultured in STK2, a serum-free medium for mesenchymal stem cells, or treated with TGF-ß1 underwent morphological changes toward an EMT appearance, along with increased expression of LEFTY and Snail. The cells also showed CSC properties, as demonstrated by increases in the aldehyde dehydrogenase (ALDH)1high activity population, number of spheroid formation, and expression of several CSC markers. Inhibition of LEFTY expression induced decreases in the number of spindle-shaped cells and CSC features, while cells stably overexpressing LEFTY exhibited enhancement of such EMT/CSC properties. Finally, treatment of cells with TGF-ß1 led to increased LEFTY expression and activation of Akt, which subsequently induced inactivation of GSK-3ß, while inhibition of GSK-3ß resulted in increased expression of both LEFTY and Snail. In clinical samples, LEFTY expression showed a tendency for positive associations with expression of vimentin, as well as Sox2 and ALDH1, in OCCCas with epithelial-like morphology, indicating a possible relationship between LEFTY and the epithelial-mesenchymal hybrid stage of the tumors. In conclusion, TGF-ß-mediated LEFTY/Akt/GSK-3ß/Snail axis may contribute to the establishment and maintenance of phenotypic characteristics of OCCCas through modulation of EMT/CSC properties.

A functional role of LEFTY during progesterone therapy for endometrial carcinoma.

BACKGROUND: The left-right determination factor (LEFTY) is a novel member of the TGF-ß/Smad2 pathway and belongs to the premenstrual/menstrual repertoire in human endometrium, but little is known about its functional role in endometrial carcinomas (Em Cas). Herein, we focused on LEFTY expression and its association with progesterone therapy in Em Cas. METHODS: Regulation and function of LEFTY, as well as its associated molecules including Smad2, ovarian hormone receptors, GSK-3ß, and cell cycle-related factors, were assessed using clinical samples and cell lines of Em Cas. RESULTS: In clinical samples, LEFTY expression was positively correlated with estrogen receptor-α, but not progesterone receptor (PR), status, and was inversely related to phosphorylated (p) Smad2, cyclin A2, and Ki-67 levels. During progesterone therapy, expression of LEFTY, pSmad2, and pGSK-3ß showed stepwise increases, with significant correlations to morphological changes toward secretory features and decreased Ki-67 values. In Ishikawa cells, an Em Ca cell line that expresses PR, progesterone treatment reduced proliferation and induced increased expression of LEFTY and pGSK-3ß, although LEFTY promoter regions were inhibited by transfection of PR. Moreover, inhibition of GSK-3ß resulted in increased LEFTY expression through a decrease in its ubiquitinated form, suggesting posttranslational regulation of LEFTY protein via GSK-3ß suppression in response to progesterone. In addition, overexpression or knockdown of LEFTY led to suppression or enhancement of Smad2-dependent cyclin A2 expression, respectively. CONCLUSION: Upregulation of LEFTY may serve as a useful clinical marker for the therapeutic effects of progesterone for Em Cas, leading to inhibition of tumor cell proliferation through alteration in Smad2-dependent transcription of cyclin A2.

Physcomitrella cyclin-dependent kinase A links cell cycle reactivation to other cellular changes during reprogramming of leaf cells.

During regeneration, differentiated plant cells can be reprogrammed to produce stem cells, a process that requires coordination of cell cycle reactivation with acquisition of other cellular characteristics. However, the factors that coordinate the two functions during reprogramming have not been determined. Here, we report a link between cell cycle reactivation and the acquisition of new cell-type characteristics through the activity of cyclin-dependent kinase A (CDKA) during reprogramming in the moss Physcomitrella patens. Excised gametophore leaf cells of P. patens are readily reprogrammed, initiate tip growth, and form chloronema apical cells with stem cell characteristics at their first cell division. We found that leaf cells facing the cut undergo CDK activation along with induction of a D-type cyclin, tip growth, and transcriptional activation of protonema-specific genes. A DNA synthesis inhibitor, aphidicolin, inhibited cell cycle progression but prevented neither tip growth nor protonemal gene expression, indicating that cell cycle progression is not required for acquisition of protonema cell-type characteristics. By contrast, treatment with a CDK inhibitor or induction of dominant-negative CDKA;1 protein inhibited not only cell cycle progression but also tip growth and protonemal gene expression. These findings indicate that cell cycle progression is coordinated with other cellular changes by the concomitant regulation through CDKA;1.

Nucleobindin 2 inhibits senescence in gastric carcinoma.

Here, we focused on the role of Nucleobindin 2 (NUCB2), a multifunctional protein, in gastric carcinoma (GC) progression. NUCB2 expression was investigated in 150 GC cases (20 non-invasive (pT1) and 130 invasive (pT2/pT3/pT4) tumors) by immunohistochemistry (IHC), and in situ hybridization for detection of the mRNA in 21 cases. Using GC cell lines, we determined whether NUCB2 expression was associated with specific cellular phenotypes. In GC clinical samples, NUCB2 was transcriptionally upregulated when compared to normal tissues. High NUCB2 expression was associated with clinicopathological factors including deep tumor invasion, lymphovascular invasion, lymph node metastasis, and advanced clinical stages, and was a significant independent predictor of unfavorable progression-free survival in 150 non-invasive and invasive GC patients. Similar findings were also evident in 72 invasive GC cases in which patients received post-operative chemotherapy, but not in 58 invasive tumors from patients who did not receive the chemotherapy. In cell lines, NUCB2 knockout inhibited proliferation, susceptibility to apoptosis, and migration capability by inducting cellular senescence; this was consistent with higher proliferation and apoptotic indices in the NUCB2 IHC-high compared to NUCB2 IHC-low GC cases. NUCB2-dependent inhibition of senescence in GC engenders aggressive tumor behavior by modulating proliferation, apoptosis, and migration.

EBP50 Depletion and Nuclear ß-Catenin Accumulation Engender Aggressive Behavior of Colorectal Carcinoma through Induction of Tumor Budding.

Ezin-radixin-moesin-binding phosphoprotein 50 (EBP50) is a scaffold protein that interacts with several partner molecules including ß-catenin. Here, we examined the crosstalk between EBP50 and nuclear catenin during colorectal carcinoma (CRC) progression. In clinical samples, there were no correlations between the subcellular location of EBP50 and any clinicopathological factors. However, EBP50 expression was significantly lower specifically in the outer areas of tumor lesions, in regions where tumor budding (BD) was observed. Low EBP50 expression was also significantly associated with several unfavorable prognostic factors, suggesting that EBP50 depletion rather than its overexpression or subcellular distribution plays an important role in CRC progression. In CRC cell lines, knockout of EBP50 induced epithelial-mesenchymal transition (EMT)-like features, decreased proliferation, accelerated migration capability, and stabilized nuclear ß-catenin due to disruption of the interaction between EBP50 and ß-catenin at the plasma membrane. In addition, Slug expression was significantly higher in outer lesions, particularly in BD areas, and was positively correlated with nuclear ß-catenin status, consistent with ß-catenin-driven transactivation of the Slug promoter. Together, our data suggest that EBP50 depletion releases ß-catenin from the plasma membrane in outer tumor lesions, allowing ß-catenin to accumulate and translocate to the nucleus, where it transactivates the Slug gene to promote EMT. This in turn triggers tumor budding and contributes to the progression of CRC to a more aggressive phase.

Interaction between membranous EBP50 and myosin 9 as a favorable prognostic factor in ovarian clear cell carcinoma.

Ezrin-radixin-moesin-binding phosphoprotein 50 (EBP50) is a scaffold protein that is required for epithelial polarity. Knockout (KO) of membranous EBP50 (Me-EBP50) in ovarian clear cell carcinoma (OCCC) cells induced an epithelial-mesenchymal transition (EMT)-like phenotype, along with decreased proliferation, accelerated migration capability, and induction of cancer stem cell (CSC)-like properties. Shotgun proteomics analysis of proteins that co-immunoprecipitated with EBP50 revealed that Me-EBP50 strongly interacts with myosin 9 (MYH9). Specific inhibition of MYH9 with blebbistatin phenocopied Me-EBP50 KO, and blebbistatin treatment potentiated the effects of Me-EBP50 KO. In OCCC cells from clinical samples, Me-EBP50 and MYH9 were co-localized at the apical plasma membrane. Patients with a combination of Me-EBP50-high and MYH9-high scores had the best prognosis for overall and progression-free survival. Our data suggest that Me-EBP50 has tumor-suppressive effects through the establishment and maintenance of epithelial polarization. By contrast, loss of Me-EBP50 expression induces EMT-like phenotypes, probably due to MYH9 dysfunction; this results in increased cell mobility and enhanced CSC-like properties, which in turn promote OCCC progression.

ADAMTSL-6 is a novel extracellular matrix protein that binds to fibrillin-1 and promotes fibrillin-1 fibril formation.

ADAMTS (A disintegrin and metalloproteinase with thrombospondin motifs)-like (ADAMTSL) proteins, a subgroup of the ADAMTS superfamily, share several domains with ADAMTS proteinases, including thrombospondin type I repeats, a cysteine-rich domain, and an ADAMTS spacer, but lack a catalytic domain. We identified two new members of ADAMTSL proteins, ADAMTSL-6alpha and -6beta, that differ in their N-terminal amino acid sequences but have common C-terminal regions. When transfected into MG63 osteosarcoma cells, both isoforms were secreted and deposited into pericellular matrices, although ADAMTSL-6alpha, in contrast to -6beta, was barely detectable in the conditioned medium. Immunolabeling at the light and electron microscopic levels showed their close association with fibrillin-1-rich microfibrils in elastic connective tissues. Surface plasmon resonance analyses demonstrated that ADAMTSL-6beta binds to the N-terminal half of fibrillin-1 with a dissociation constant of approximately 80 nm. When MG63 cells were transfected or exogenously supplemented with ADAMTSL-6, fibrillin-1 matrix assembly was promoted in the early but not the late stage of the assembly process. Furthermore, ADAMTSL-6 transgenic mice exhibited excessive fibrillin-1 fibril formation in tissues where ADAMTSL-6 was overexpressed. All together, these results indicated that ADAMTSL-6 is a novel microfibril-associated protein that binds directly to fibrillin-1 and promotes fibrillin-1 matrix assembly.

Transcriptome-based systematic identification of extracellular matrix proteins.

Extracellular matrix (ECM), which provides critical scaffolds for all adhesive cells, regulates proliferation, differentiation, and apoptosis. Different cell types employ customized ECMs, which are thought to play important roles in the generation of so-called niches that contribute to cell-specific functions. The molecular entities of these customized ECMs, however, have not been elucidated. Here, we describe a strategy for transcriptome-wide identification of ECM proteins based on computational screening of >60,000 full-length mouse cDNAs for secreted proteins, followed by in vitro functional assays. These assays screened the candidate proteins for ECM-assembling activities, interactions with other ECM molecules, modifications with glycosaminoglycans, and cell-adhesive activities, and were then complemented with immunohistochemical analysis. We identified 16 ECM proteins, of which seven were localized in basement membrane (BM) zones. The identification of these previously unknown BM proteins allowed us to construct a body map of BM proteins, which represents the comprehensive immunohistochemistry-based expression profiles of the tissue-specific customization of BMs.