A novel function for p21Cip1 and acetyltransferase p/CAF as critical transcriptional regulators of TGFβ-mediated breast cancer cell migration and invasion

Multiple Endocrine Neoplasia Type 1 Regulates TGFβ-Mediated Suppression of Tumor Formation and Metastasis in Melanoma

Over the past few decades, the worldwide incidence of cutaneous melanoma, a malignant neoplasm arising from melanocytes, has been increasing markedly, leading to the highest rate of skin cancer-related deaths. While localized tumors are easily removed by excision surgery, late-stage metastatic melanomas are refractory to treatment and exhibit a poor prognosis. Consequently, unraveling the molecular mechanisms underlying melanoma tumorigenesis and metastasis is crucial for developing novel targeted therapies. We found that the multiple endocrine neoplasia type 1 (MEN1) gene product Menin is required for the transforming growth factor beta (TGFβ) signaling pathway to induce cell growth arrest and apoptosis in vitro and prevent tumorigenesis in vivo in preclinical xenograft models of melanoma. We further identified point mutations in two MEN1 family members affected by melanoma that led to proteasomal degradation of the MEN1 gene product and to a loss of TGFβ signaling. Interestingly, blocking the proteasome degradation pathway using an FDA-approved drug and RNAi targeting could efficiently restore MEN1 expression and TGFβ transcriptional responses. Together, these results provide new potential therapeutic strategies and patient stratification for the treatment of cutaneous melanoma.

pVHL-mediated SMAD3 degradation suppresses TGF-β signaling

Transforming growth factor β (TGF-β) signaling plays a fundamental role in metazoan development and tissue homeostasis. However, the molecular mechanisms concerning the ubiquitin-related dynamic regulation of TGF-β signaling are not thoroughly understood. Using a combination of proteomics and an siRNA screen, we identify pVHL as an E3 ligase for SMAD3 ubiquitination. We show that pVHL directly interacts with conserved lysine and proline residues in the MH2 domain of SMAD3, triggering degradation. As a result, the level of pVHL expression negatively correlates with the expression and activity of SMAD3 in cells, Drosophila wing, and patient tissues. In Drosophila, loss of pVHL leads to the up-regulation of TGF-β targets visible in a downward wing blade phenotype, which is rescued by inhibition of SMAD activity. Drosophila pVHL expression exhibited ectopic veinlets and reduced wing growth in a similar manner as upon loss of TGF-β/SMAD signaling. Thus, our study demonstrates a conserved role of pVHL in the regulation of TGF-β/SMAD3 signaling in human cells and Drosophila wing development.

Oncogenic and Tumor Suppressive Components of the Cell Cycle in Breast Cancer Progression and Prognosis

Cancer, a disease of inappropriate cell proliferation, is strongly interconnected with the cell cycle. All cancers consist of an abnormal accumulation of neoplastic cells, which are propagated toward uncontrolled cell division and proliferation in response to mitogenic signals. Mitogenic stimuli include genetic and epigenetic changes in cell cycle regulatory genes and other genes which regulate the cell cycle. This suggests that multiple, distinct pathways of genetic alterations lead to cancer development. Products of both oncogenes (including cyclin-dependent kinase (CDKs) and cyclins) and tumor suppressor genes (including cyclin-dependent kinase inhibitors) regulate cell cycle machinery and promote or suppress cell cycle progression, respectively. The identification of cyclins and CDKs help to explain and understand the molecular mechanisms of cell cycle machinery. During breast cancer tumorigenesis, cyclins A, B, C, D1, and E; cyclin-dependent kinase (CDKs); and CDK-inhibitor proteins p16, p21, p27, and p53 are known to play significant roles in cell cycle control and are tightly regulated in normal breast epithelial cells. Following mitogenic stimuli, these components are deregulated, which promotes neoplastic transformation of breast epithelial cells. Multiple studies implicate the roles of both types of components-oncogenic CDKs and cyclins, along with tumor-suppressing cyclin-dependent inhibitors-in breast cancer initiation and progression. Numerous clinical studies have confirmed that there is a prognostic significance for screening for these described components, regarding patient outcomes and their responses to therapy. The aim of this review article is to summarize the roles of oncogenic and tumor-suppressive components of the cell cycle in breast cancer progression and prognosis.

Lycorine hydrochloride inhibits melanoma cell proliferation, migration and invasion via down-regulating p21Cip1/WAF1

Lycorine hydrochloride (LH) is an active ingredient sourced from the medicinal herb Lycoris radiata. Previous studies have suggested that LH exerts tumor suppression activity in several human cancers. However, the anti-cancer effect of LH in melanoma and the potential molecular mechanisms still need to be further studied. p21Cip1/WAF1, unlike its traditional cyclin-dependent kinase (CDK) inhibitor role, is believed to act as an oncogene under certain cellular conditions. In this research, an increased expression of p21Cip1/WAF1 was found in human melanoma tissues and positively related to the tumor invasion depth. High level of p21Cip1/WAF1 was found to correlate with bad outcomes of melanoma patients by Kaplan-Meier survival analysis. Functional experiments demonstrated that the proliferation, migration and invasion ability of A375 and MV3 melanoma cells was powerfully inhibited by LH through inducing S phase cell cycle arrest and regulating epithelial-mesenchymal transition (EMT). In NOD/SCID mice model, LH effectively inhibited the xenograft tumor growth and lung metastasis of A375 cells. Further research revealed that LH reduced p21Cip1/WAF1 protein by accelerating its ubiquitination. Importantly, the LH-induced suppression of cell proliferation and metastasis was rescued by p21Cip1/WAF1 overexpression, both in vitro an in vivo. Taken together, LH, which suppresses the proliferation and metastasis of melanoma cells via down-regulating p21Cip1/WAF1, is expected to be developed as an effective medicine for melanoma therapy.

TGFβ/cyclin D1/Smad-mediated inhibition of BMP4 promotes breast cancer stem cell self-renewal activity

Basal-like triple-negative breast cancers (TNBCs) display poor prognosis, have a high risk of tumor recurrence, and exhibit high resistance to drug treatments. The TNBC aggressive features are largely due to the high proportion of cancer stem cells present within these tumors. In this study, we investigated the interplay and networking pathways occurring between TGFβ family ligands in regulating stemness in TNBCs. We found that TGFβ stimulation of TNBCs resulted in enhanced tumorsphere formation efficiency and an increased proportion of the highly tumorigenic CD44^high/CD24^low cancer stem cell population. Analysis of the TGFβ transcriptome in TNBC cells revealed bone morphogenetic protein4 (BMP4) as a main TGFβ-repressed target in these tumor cells. We further found that BMP4 opposed TGFβ effects on stemness and potently decreased cancer stem cell numbers, thereby acting as a differentiation factor in TNBC. At the molecular level, we found that TGFβ inhibition of BMP4 gene expression is mediated through the Smad pathway and cyclin D1. In addition, we also found BMP4 to act as a pro-differentiation factor in normal mammary epithelial cells and promote mammary acinar formation in 3D cell culture assays. Finally, and consistent with our in vitro results, in silico patient data analysis defined BMP4 as a potential valuable prognosis marker for TNBC patients.

Annurca apple polyphenol extract promotes mesenchymal-to-epithelial transition and inhibits migration in triple-negative breast cancer cells through ROS/JNK signaling

Aberrant activation of epithelial-to-mesenchymal transition has been shown to correlate with triple-negative breast cancer (TNBC) progression and metastasis. Thus, the induction of the reverse process might offer promising opportunities to restrain TNBC metastatic spreading and related mortality. Recently, the Annurca apple polyphenol extract (APE) has been highlighted as a multi-faceted agent that selectively kills TNBC cells by ROS generation and sustained JNK activation. Here, by qualitatively and quantitatively monitoring the real-time movements of live cells we provided the first evidence that APE inhibited the migration of MDA-MB-231 and MDA-MB-468 TNBC cells and downregulated metalloproteinase-2 and metalloproteinase-9. In MDA-MB-231 cells APE decreased SMAD-2/3 and p-SMAD-2/3 levels, increased E-cadherin/N-cadherin protein ratio, induced the switch from N-cadherin to E-cadherin expression and greatly reduced vimentin levels. Confocal and scanning electron microscopy imaging of APE-treated MDA-MB-231 cells evidenced a significant cytoskeletal vimentin and filamentous actin reorganization and revealed considerable changes in cell morphology highlighting an evident transition from the mesenchymal to epithelial phenotype with decreased migratory features. Notably, all these events were reverted by N-acetyl-l-cysteine and JNK inhibitor SP600125 furnishing evidence that APE exerted its effects through the activation of ROS/JNK signaling. The overall data highlighted APE as a potential preventing agent for TNBC metastasis.

The lncRNA SLNCR Recruits the Androgen Receptor to EGR1-Bound Genes in Melanoma and Inhibits Expression of Tumor Suppressor p21

Melanoma is the deadliest form of skin cancer, affecting men more frequently and severely than women. Although recent studies suggest that differences in activity of the androgen receptor (AR) underlie the observed sex bias, little is known about AR activity in melanoma. Here we show that AR and EGR1 bind to the long non-coding RNA SLNCR and increase melanoma proliferation through coordinated transcriptional regulation of several growth-regulatory genes. ChIP-seq reveals that ligand-free AR is enriched on SLNCR-regulated melanoma genes and that AR genomic occupancy significantly overlaps with EGR1 at consensus EGR1 binding sites. We present a model in which SLNCR recruits AR to EGR1-bound genomic loci and switches EGR1-mediated transcriptional activation to repression of the tumor suppressor p21^Waf1/Cip1. Our data implicate the regulatory triad of SLNCR, AR, and EGR1 in promoting oncogenesis and may help explain why men have a higher incidence of and more rapidly progressive melanomas compared with women.

Targeting the C-Terminal Domain Small Phosphatase 1

The human C-terminal domain small phosphatase 1 (CTDSP1/SCP1) is a protein phosphatase with a conserved catalytic site of DXDXT/V. CTDSP1’s major activity has been identified as dephosphorylation of the 5th Ser residue of the tandem heptad repeat of the RNA polymerase II C-terminal domain (RNAP II CTD). It is also implicated in various pivotal biological activities, such as acting as a driving factor in repressor element 1 (RE-1)-silencing transcription factor (REST) complex, which silences the neuronal genes in non-neuronal cells, G1/S phase transition, and osteoblast differentiation. Recent findings have denoted that negative regulation of CTDSP1 results in suppression of cancer invasion in neuroglioma cells. Several researchers have focused on the development of regulating materials of CTDSP1, due to the significant roles it has in various biological activities. In this review, we focused on this emerging target and explored the biological significance, challenges, and opportunities in targeting CTDSP1 from a drug designing perspective.

RAGE acts as an oncogenic role and promotes the metastasis of human lung cancer

RAGE (receptor for advanced glycation end-product) is thought to be associated with metastasis and poor prognosis of various types of cancer. However, RAGE is constitutively expressed in the normal lung and down-regulated in cancerous lung, while the opposite evidence shows that RAGE-mediated signaling contributes to the tumorigenesis of lung cancer. Therefore, the role of RAGE in lung cancer progression is still unclear to be further investigated. In this study, RAGE-overexpressed stable clones of human lung cancer A549 cells and two local lung adenocarcinoma cell lines CL1-0 and CL1-5 were utilized to verify the effect of RAGE on lung cancer cells while the in vivo xenograft animal model was further performed to evaluate the role of RAGE in the progression of lung cancer. The growth of A549 cells was inhibited by RAGE overexpression. p53-dependent p21^CIP1 expression contributed to RAGE-induced growth inhibition by suppressing CDK2 kinase activity and retinoblastoma protein (RB) phosphorylation in vitro. On the other hand, RAGE overexpression promoted migration, invasion, and mesenchymal features of lung adenocarcinoma cells through ERK signaling. Furthermore, an in vivo xenograft experiment indicated that RAGE promoted the metastasis of lung cancer cells with p21^CIP1 up-regulation, ERK activation, and the changes of EMT markers. Regarding to the involvement of tumor-associated macrophage (TAM) in the microenvironment, we monitored the expressions of TAM markers including CD68 and CD163 as well as angiogenesis marker CD31 in xenograft slice. The data showed that RAGE might induce the accumulation of TAM in lung cancer cells and further accelerate the in vivo tumor growth. In summary, our study provides evidence indicating the distinct in vitro and in vivo effects of RAGE and related mechanisms on tumor growth and metastasis, which shed light on the oncogenic role of RAGE in lung cancer.

Effects of S‑adenosyl‑L‑methionine on the invasion and migration of head and neck squamous cancer cells and analysis of the underlying mechanisms

S-Adenosyl-L-methionine (AdoMet) is the principal methyl donor in transmethylation reactions fundamental to sustaining epigenetic modifications. Over the past decade, AdoMet has been extensively investigated for its anti- proliferative, pro-apoptotic and anti-metastatic roles in several types of human cancer. Head and neck squamous cell carcinoma (HNSCC) is the sixth most common type of cancer worldwide, and is an aggressive type of cancer that is associated with a high recurrence rate, metastasis and poor treatment outcomes. The present study demonstrates, for the first time, to the best of our knowledge, that AdoMet induces cell cycle arrest and inhibits the migratory and invasive ability of two different HNSCC cell lines, oral Cal-33 and laryngeal JHU-SCC-011 cells. In both cell lines, AdoMet attenuated cell cycle progression, decreased the protein level of several cyclins and downregulated the expression of p21 cell cycle inhibitor. Moreover, AdoMet was able to inhibit Cal-33 and JHU-SCC-011 cell migration in a dose-dependent manner after 24 and 48 h, respectively, and also induced a significant reduction in the cell invasive ability, as demonstrated by Matrigel invasion assay monitored by the xCELLigence RTCA system. Western blot analysis of several migration and invasion markers confirmed the inhibitory effects exerted by AdoMet on these processes and highlighted AKT, β-catenin and small mothers against decapentaplegic (SMAD) as the main signaling pathways modulated by AdoMet. The present study also demonstrated that the combination of AdoMet and cisplatin synergistically inhibited HNSCC cell migration. Taken together, these findings demonstrate that the physiological compound, AdoMet, affects the motility and extracellular matrix invasive capability in HNSCC. Thus, AdoMet may prove to be a good candidate for future drug development against metastatic cancer.

The Role of the Cyclin Dependent Kinase Inhibitor p21cip1/waf1 in Targeting Cancer: Molecular Mechanisms and Novel Therapeutics

p21^cip1/waf1 mediates various biological activities by sensing and responding to multiple stimuli, via p53-dependent and independent pathways. p21 is known to act as a tumor suppressor mainly by inhibiting cell cycle progression and allowing DNA repair. Significant advances have been made in elucidating the potential role of p21 in promoting tumorigenesis. Here, we discuss the involvement of p21 in multiple signaling pathways, its dual role in cancer, and the importance of understanding its paradoxical functions for effectively designing therapeutic strategies that could selectively inhibit its oncogenic activities, override resistance to therapy and yet preserve its tumor suppressive functions.

The Multifaceted p21 (Cip1/Waf1/CDKN1A) in Cell Differentiation, Migration and Cancer Therapy

Loss of cell cycle control is characteristic of tumorigenesis. The protein p21 is the founding member of cyclin-dependent kinase inhibitors and an important versatile cell cycle protein. p21 is transcriptionally controlled by p53 and p53-independent pathways. Its expression is increased in response to various intra- and extracellular stimuli to arrest the cell cycle ensuring genomic stability. Apart from its roles in cell cycle regulation including mitosis, p21 is involved in differentiation, cell migration, cytoskeletal dynamics, apoptosis, transcription, DNA repair, reprogramming of induced pluripotent stem cells, autophagy and the onset of senescence. p21 acts either as a tumor suppressor or as an oncogene depending largely on the cellular context, its subcellular localization and posttranslational modifications. In the present review, we briefly mention the general functions of p21 and summarize its roles in differentiation, migration and invasion in detail. Finally, regarding its dual role as tumor suppressor and oncogene, we highlight the potential, difficulties and risks of using p21 as a biomarker as well as a therapeutic target.

Function of p21 (Cip1/Waf1/CDKN1A) in Migration and Invasion of Cancer and Trophoblastic Cells

Tumor progression and pregnancy have several features in common. Tumor cells and placental trophoblasts share many signaling pathways involved in migration and invasion. Preeclampsia, associated with impaired differentiation and migration of trophoblastic cells, is an unpredictable and unpreventable disease leading to maternal and perinatal mortality and morbidity. Like in tumor cells, most pathways, in which p21 is involved, are deregulated in trophoblasts of preeclamptic placentas. The aim of the present study was to enlighten p21’s role in tumorigenic choriocarcinoma and trophoblastic cell lines. We show that knockdown of p21 induces defects in chromosome movement during mitosis, though hardly affecting proliferation and cell cycle distribution. Moreover, suppression of p21 compromises the migration and invasion capability of various trophoblastic and cancer cell lines mediated by, at least partially, a reduction of the extracellular signal-regulated kinase 3, identified using transcriptome-wide profiling, real-time PCR, and Western blot. Further analyses show that downregulation of p21 is associated with reduced matrix metalloproteinase 2 and tissue inhibitor of metalloproteinases 2. This work evinces that p21 is involved in chromosome movement during mitosis as well as in the motility and invasion capacity of trophoblastic and cancer cell lines.

Theragnosis by a miR-141-3p molecular beacon: simultaneous detection and sensitization of 5-fluorouracil resistant colorectal cancer cells through the activation of the TRIM13-associated apoptotic pathway

We developed a molecular beacon targeting miR-141-3p, aberrantly increased in 5-fluorouracil-resistant colorectal cancer cells (R-CRCCs). It consists of a fluorophore-labeled oligonucleotide, antisense to miR-141-3p, and a quencher. It detected R-CRCCs and recovered the chemosensitivity of them to 5-fluorouracil by hybridization with miR-141-3p, which is applicable to cancer treatment.

SMAD3 inducing the transcription of STYK1 to promote the EMT process and improve the tolerance of ovarian carcinoma cells to paclitaxel

OBJECTIVE

To figure out the relationship between SMAD3 and serine-threonine tyrosine kinase (STYK1) in ovarian carcinoma cell's paclitaxel resistance.

METHODS

The quantitative reverse transcription-polymerase chain reactpostion and Western blot analysis were used to analyze RNA and protein content of SMAD3 and STYK1, respectively. The chromatin immunoprecipitation assay was used to confirm the binding site of SMAD3 to the STYK1 promoter region. Transwell assay was used to detect cell invasion and migration, and Western Blot was used to detect the marker proteins (vimentin and E-cadherin) of epithelial-mesenchymal transition (EMT) process. MTT and apoptosis assay were used to, respectively, measure cell vitality and apoptosis. In vivo experiments, rats were subcutaneously implanted with A2780 cells to establish an animal model of ovarian cancer and the survival curve was drawn.

RESULTS

Upregulating SMAD3 induced the expression of STYK1 in ovarian cancer cell lines. STYK1 is a direct transcriptional target of SMAD3. Upregulating STYK1 improved the paclitaxel resistance of ovarian carcinoma cells. Upregulating STYK1 promoted cell invasion, migration, and the EMT process, and SMAD3 had the same effect with STYK1 on cell invasion, cell migration, and the EMT process. The animal assay showed that downregulating STYK1 inhibited the EMT process and the paclitaxel resistance, further promoting the treatment of cervical cancer.

CONCLUSION

SMAD3 combined with the promoter region of STYK1 to promote the transcription process of STYK1, thereby promoting the EMT process and paclitaxel resistance of ovarian cancer cells.

Differential expression of TGFβ isoforms in breast cancer highlights different roles during breast cancer progression

While TGFβ plays a critical role in tumor formation and progression, the role and contribution of its three different isoforms remain unclear. In this study, we aimed at elucidating the prognostic value of the TGFβ isoforms and assessed their expression levels in breast cancer patients at different stages of the disease. We found higher levels of TGFβ1 and TGFβ3 in cancer patients compared to normal tissues, with no significant changes in TGFβ2 expression. Similarly, TGFβ1 and TGFβ3, but not TGFβ2, showed higher expression levels in advanced lymph node-positive and metastatic tumors, suggesting different roles for the different isoforms in tumor progression and the metastatic process, while in the least aggressive molecular subtype (luminal A), expression of the three TGFβ isoforms significantly correlated with expression of both TGFβ receptors, such correlation only occurred between TGFβ1 and TGFβ3 and the TGFβ type II receptor (TβRII) in the highly aggressive basal-like subtype. Interestingly, a distinct and somehow opposite pattern was observed in HER-2 tumors, only showing significant association pattern between TGFβ2 and the TGFβ type I receptor (TβRI). Finally, the three TGFβ isoforms showed distinct association patterns with patient outcome depending on the different molecular subtype, highlighting context-dependent, differential prognostic values.

Expression and prognostic significance of cyclin-dependent kinase inhibitor 1A in patients with resected gastric adenocarcinoma

Cyclin-dependent kinase inhibitor 1A (CDKN1A) is an important cell cycleregulator, and has been identified to exhibit aberrant expression in various types of cancer tissues. However, the association between CDKN1A expression level and prognosis in patients with resected gastric adenocarcinoma (RGA) requires additional elucidation. In the present study, the CDKN1A expression profile in RGA tissues obtained from 217 patients were analyzed using immunohistochemistry. Its prognostic significance was evaluated by using the χ² test, Kaplan-Meier curves and the log-rank test, and a multivariate Cox model analysis, during a median follow-up time of 51 months. The results demonstrated that CDKN1A expression was significantly correlated with lymph node metastasis (LNM; P=0.001), recurrence (P<0.001) and overall survival (OS; P<0.001). In addition, the recurrence-free survival (RFS) and OS times were significantly shorter in patients with low CDKN1A expression compared with those with high CDKN1A expression (RFS, 20 months vs. 69 months, P<0.001; and OS, 32 months vs. 70 months, P<0.001, respectively). Multivariate analysis additionally confirmed that low CDKN1A expression was significantly correlated with an increased risk of LNM (P=0.001), recurrence (P<0.001) and mortality (P<0.001). Therefore, these data suggest that low expression of CDKN1A has independent prognostic significance indicative of tumor progression and poor survival in patients with RGA. Evaluation of CDKN1A expression may assist in determining prognosis in patients with RGA.

Transforming Growth Factor-beta Regulation of Ephrin Type-A Receptor 4 Signaling in Breast Cancer Cellular Migration

Breast cancer consists of a range of tumor subtypes with different clinical characteristics, disease prognosis, and treatment-response. Luminal breast cancer has the best prognosis while basal-like breast cancer (BLBC) represents the worst subtype. Transforming growth factor-beta (TGFβ) plays a prominent role in stimulating the migration and invasion of malignant breast cancer cells contributing to tumor progression. In this study, we identified the Ephrin type-A receptor 4 (EPHA4) as a novel target of TGFβ in breast cancer. Moreover, we show that TGFβ induction of EPHA4 gene expression is specific to basal-like tumors and is required for TGFβ-mediated cell migration. We further addressed the mechanism and found EPHA4 to be required for TGFβ-mediated cell migration in breast cancer through TGFβ-induced short term and long term activation of RhoGTPases. Finally, our data revealed a strong association between high EPHA4 expression and advanced tumor stage, aggressive BLBC molecular subtype and poor prognosis. Importantly, we found significant co-expression of EPHA4 and the TGFβ receptor type-2 (TGFβR2) in breast cancer subtypes associated with increased tumor relapse and drug resistance. Together, this study highlight the important role of the TGFβ/EPHA4 signaling axis in mediating tumor aggressiveness and poor patient survival in human breast cancer.

ITIH5 induces a shift in TGF-β superfamily signaling involving Endoglin and reduces risk for breast cancer metastasis and tumor death

ITIH5 has been proposed being a novel tumor suppressor in various tumor entities including breast cancer. Recently, ITIH5 was furthermore identified as metastasis suppressor gene in pancreatic carcinoma. In this study we aimed to specify the impact of ITIH5 on metastasis in breast cancer. Therefore, DNA methylation of ITIH5 promoter regions was assessed in breast cancer metastases using the TCGA portal and methylation-specific PCR (MSP). We reveal that the ITIH5 upstream promoter region is particularly responsible for ITIH5 gene inactivation predicting shorter survival of patients. Notably, methylation of this upstream ITIH5 promoter region was associated with disease progression, for example, abundantly found in distant metastases. In vitro, stably ITIH5-overexpressing MDA-MB-231 breast cancer clones were used to analyze cell invasion and to identify novel ITIH5-downstream targets. Indeed, ITIH5 re-expression suppresses invasive growth of MDA-MB-231 breast cancer cells while modulating expression of genes involved in metastasis including Endoglin (ENG), an accessory TGF-β receptor, which was furthermore co-expressed with ITIH5 in primary breast tumors. By performing in vitro stimulation of TGF-β signaling using TGF-β1 and BMP-2 we show that ITIH5 triggered a TGF-β superfamily signaling switch contributing to downregulation of targets like Id1, known to endorse metastasis. Moreover, ITIH5 predicts longer overall survival (OS) only in those breast tumors that feature high ENG expression or inversely regulated ID1 suggesting a clinical and functional impact of an ITIH5-ENG axis for breast cancer progression. Hence, we provide evidence that ITIH5 may represent a novel modulator of TGF-β superfamily signaling involved in suppressing breast cancer metastasis.

KiSS1 gene as a novel mediator of TGFβ-mediated cell invasion in triple negative breast cancer

The invasive and metastatic phenotypes of breast cancer correlate with high recurrence rates and poor survival outcomes. Transforming growth factor-β (TGFβ) promotes tumor progression and metastasis in aggressive breast cancer. Here, we identified the kisspeptin KiSS1 as a downstream target of canonical TGFβ/Smad2 pathway in triple negative breast cancer cells. We also found KiSS1 expression to be required for TGFβ-induced cancer cell invasion. Indeed, knockdown expression of KiSS1 blocked TGFβ-mediated cancer cell invasion as well as metalloproteinase (MMP9) expression and activity. Interestingly, Kisspeptin-10 (KP-10), the smallest active form of kisspeptin also stimulates cancer cell invasive behavior through activation of MAPK/Erk pathway. We described a positive feedback loop between KiSS1 and p21 downstream of TGFβ, further contributing to TGFβ-induced cancer cell invasion. Lastly, we explored both the clinical utility of KiSS1 as a lymph node involvement predictive tool and its potential as a therapeutic target. We found KiSS1 high expression to correlate with lymph node positive status. Furthermore, blocking KiSS1 using a specific small peptide antagonist (p234) impaired TGFβ-mediated cell invasion and MMP9 induction. Together, our results define an essential role of KiSS1 in regulating TGFβ pro-invasive effects and define KiSS1 as a therapeutic new target for triple negative breast cancer.

FNC efficiently inhibits mantle cell lymphoma growth

FNC, 2'-deoxy-2'-β-fluoro-4'-azidocytidine, is a novel cytidine analogue, that has shown strong antiproliferative activity in human lymphoma, lung adenocarcinoma and acute myeloid leukemia. In this study, we investigated the effects of FNC on mantle cell lymphoma (MCL) and the underlying mechanisms. In in vitro experiments, cell viability was detected by the CCK8 assay, and cell cycle progression and apoptosis were assessed by flow cytometry, and the expression of relative apoptosis proteins were detected by Western Blot. The in vivo antitumor effect of FNC was investigated in a SCID xenograft model. Finally, the mechanisms of action of FNC were assessed using a whole human genome expression profile chip. The data showed that FNC inhibited cell growth in a dose- and time-dependent manner, and FNC could induce apoptosis by the death recepter pathways in JeKo-1 cells and arrest the cell cycle in the G1/S or G2/M phase. Notably, FNC showed in vivo efficacy in mice bearing JeKo-1 xenograft tumors. Gene expression profile analysis revealed that the differentially expressed genes were mainly focused on the immune system process, cellular process and death. These findings implied that FNC may be a valuable therapeutic in mantle cell lymphoma and provided an experimental basis for the early clinical application of FNC.

Analysis of gene expression changes associated with human carcinoma-associated fibroblasts in non-small cell lung carcinoma

Background

This study aimed to investigate the gene expression changes associated with carcinoma-associated fibroblasts (CAFs) involving in non-small cell lung carcinoma (NSCLC).

Methods

We downloaded the GEO series GSE22862, which contained matched gene expression values for 15 CAF and normal fibroblasts samples, and series GSE27289 containing SNP genotyping for four matched NSCLC samples. The differentially expressed genes in CAF samples were identified using the limma package in R. Then we performed gene ontology (GO) and pathway enrichment analysis and protein–protein interaction (PPI) network construction using the identified DEGs. Moreover, aberrant cell fraction, ploidy, allele-specific copy number, and loss of heterozygosity (LOH) within CAF cells were analyzed using the allele-specific copy number analysis.

Results

We obtained 545 differentially expressed genes between CAF and normal fibroblasts samples. The up-regulated genes are mainly involved in GO terms such as positive regulation of cell migration and extracellular region, while the down-regulated genes participate in the lung development and extracellular region. Multiple genes including bone morphogenetic protein 4 (BMP4) and transforming growth factor, beta 3 (TGFB3) are involved in the TGF-β signaling pathway. Genes including BMP4, TGFBI and matrix Gla protein (MGP) were hub genes. Moreover, no LOH event for BMP4 and MGP was found, that for sphingosine kinase 1 (SPHK1) was 70%, and for TGFBI was 40%.

Conclusion

Our data suggested that BMP4, MGP, TGFBI, and SPHK1 may be important in CAFs-associated NSCLC, and the abnormal expression and high LOH frequency of them may be used as the diagnosis targets of CAFs in NSCLC.

Cyclooxygenase-2 regulates TGFβ-induced cancer stemness in triple-negative breast cancer

Triple negative breast cancer (TNBC), an aggressive subtype of breast cancer, display poor prognosis and exhibit resistance to conventional therapies, partly due to an enrichment in breast cancer stem cells (BCSCs). Here, we investigated the role of the cyclooxygenase-2 (COX-2), a downstream target of TGFβ, in regulating BCSCs in TNBC. Bioinformatics analysis revealed that COX-2 is highly expressed in TNBC and that its expression correlated with poor survival outcome in basal subtype of breast cancer. We also found TGFβ-mediated COX-2 expression to be Smad3-dependent and to be required for BCSC self-renewal and expansion in TNBCs. Knocking down COX-2 expression strikingly blocked TGFβ-induced tumorsphere formation and TGFβ-induced enrichment of the two stem-like cell populations, CD24^lowCD44^high and ALDH+ BCSCs. Blocking COX-2 activity, using a pharmacological inhibitor also prevented TGFβ-induced BCSC self-renewal. Moreover, we found COX-2 to be required for TGFβ-induced expression of mesenchymal and basal breast cancer markers. In particular, we found that TGFβ-induced expression of fibronectin plays a central role in TGFβ-mediated breast cancer stemness. Together, our results describe a novel role for COX-2 in mediating the TGFβ effects on BCSC properties and imply that targeting the COX-2 pathway may prove useful for the treatment of TNBC by eliminating BCSCs.

Divide or Conquer: Cell Cycle Regulation of Invasive Behavior

Cell invasion through the basement membrane (BM) occurs during normal embryonic development and is a fundamental feature of cancer metastasis. The underlying cellular and genetic machinery required for invasion has been difficult to identify, due to a lack of adequate in vivo models to accurately examine invasion in single cells at subcellular resolution. Recent evidence has documented a functional link between cell cycle arrest and invasive activity. While cancer progression is traditionally thought of as a disease of uncontrolled cell proliferation, cancer cell dissemination, a critical aspect of metastasis, may require a switch from a proliferative to an invasive state. In this work, we review evidence that BM invasion requires cell cycle arrest and discuss the implications of this concept with regard to limiting the lethality associated with cancer metastasis.

DHX32 expression is an indicator of poor breast cancer prognosis

Emerging evidence suggests that DEAH-box polypeptide 32 (DHX32) serves an important role in the progression and metastasis of cancer. However, the role of DHX32 in breast cancer remains to be completely elucidated. The aim of the present study was to evaluate the expression and clinical significance of DHX32 in breast cancer. The reverse transcription-quantitative polymerase chain reaction was performed to analyze DHX32 messenger (m)RNA expression, and western blotting and immunohistochemistry were performed to examine DHX32 protein expression in breast cancer and adjacent non-cancerous tissues. The association in breast cancer between DHX32 expression, clinicopathological features and prognosis was analyzed using 193 breast cancer tissue samples. The results of the present study demonstrated that breast cancer tissues exhibited increased DHX32 mRNA and protein expression compared with adjacent non-cancerous tissues (P<0.001). In addition, DHX32 expression was significantly associated with breast cancer clinical stage (P=0.006), histological grade (P=0.029), lymph node metastasis (P<0.001) and expression of the proliferation marker Ki-67 (P=0.004). Kaplan-Meier estimator analysis indicated that increased DHX32 expression is associated with poor prognosis in patients with breast cancer. Furthermore, the Cox proportional hazards model indicated that DHX32 expression is an independent prognostic factor for decreased overall survival and disease-free survival in patients with breast cancer. In conclusion, the results of the present study suggest that DHX32 overexpression is an unfavorable prognostic biomarker in breast cancer and a potential therapeutic target of future breast cancer treatments.

CDK4 regulates cancer stemness and is a novel therapeutic target for triple-negative breast cancer

Triple negative breast cancers exhibit very aggressive features and poor patient outcomes. These tumors are enriched in cancer stem cells and exhibit resistance to most treatments and chemotherapy. In this study, we found the cyclin-dependent kinase (CDK4) to act as a cancer stem cell regulator and novel prognostic marker in triple negative breast cancers. We found CDK4 to be highly expressed in these tumors and its expression to correlate with poor overall and relapse free survival outcomes, high tumor grade and poor prognostic features of triple negative breast cancer patients. Moreover, we found that blocking CDK4 expression or kinase activity, using a pharmacological inhibitor prevented breast cancer stem cell self-renewal. Interestingly, suppression of CDK4 expression or kinase activity reversed the basal-B TNBC mesenchymal phenotype to an epithelial- and luminal-like phenotype which correlates with better clinical prognosis. Finally, blocking CDK4 activity efficiently eliminated both normal and chemotherapy-resistant cancer cells in triple negative breast cancers, highlighting CDK4 as a promising novel therapeutic target for these aggressive breast tumors.

A dual prognostic role for the TGFβ receptors in human breast cancer

The transforming growth factor-β (TGFβ) plays a dual role in breast cancer, acting as a tumor suppressor in early carcinomas while promoting tumor metastasis in more advanced breast carcinoma. As a result, the prognostic role of TGFβ and its signaling components in breast cancer remains unclear. Here we evaluated the expression levels of TGFβ signaling receptors TβRII and TβRI using human breast cancer tissue microarrays and a large publicly available gene profiling database in relation to various clinicopathological parameters. Our results indicate that breast cancer tissues express lower TβRII and TβRI protein levels compared with normal breast tissue. In contrast to TβRI expression, TβRII mRNA expression levels were also significantly downregulated in invasive breast cancer compared with normal breast tissue (4.18-fold downregulation, P=9.3×10^-115). Interestingly, within the cancer cases analyzed, our results revealed a direct correlation between high TβRII and TβRI expression levels and classic poor prognostic clinicopathological parameters, including larger tumor size, advanced tumor stage, and poorly differentiated tumors. Next, we examined TGFβ receptors' expression in relation to breast cancer molecular subtypes. Importantly, our results revealed that whereas expression of TGFβ receptors in luminal A and triple-negative breast cancer showed no correlation with patient outcome, their expression in luminal B and HER2 subtypes showed significant association with favorable patient outcome. Together, these results indicate that although TGFβ receptors are downregulated in breast cancer, their expression in tumors is an indicator of aggressive breast cancer phenotype. Moreover, the relation between TGFβ pathway and patient outcome is breast cancer subtype dependent.

The miR-17-92 cluster counteracts quiescence and chemoresistance in a distinct subpopulation of pancreatic cancer stem cells

OBJECTIVE

Cancer stem cells (CSCs) represent the root of many solid cancers including pancreatic ductal adenocarcinoma, are highly chemoresistant and represent the cellular source for disease relapse. However the mechanisms involved in these processes still need to be fully elucidated. Understanding the mechanisms implicated in chemoresistance and metastasis of pancreatic cancer is critical to improving patient outcomes.

DESIGN

Micro-RNA (miRNA) expression analyses were performed to identify functionally defining epigenetic signatures in pancreatic CSC-enriched sphere-derived cells and gemcitabine-resistant pancreatic CSCs.

RESULTS

We found the miR-17-92 cluster to be downregulated in chemoresistant CSCs versus non-CSCs and demonstrate its crucial relevance for CSC biology. In particular, overexpression of miR-17-92 reduced CSC self-renewal capacity, in vivo tumourigenicity and chemoresistance by targeting multiple NODAL/ACTIVIN/TGF-β1 signalling cascade members as well as directly inhibiting the downstream targets p21, p57 and TBX3. Overexpression of miR-17-92 translated into increased CSC proliferation and their eventual exhaustion via downregulation of p21 and p57. Finally, the translational impact of our findings could be confirmed in preclinical models for pancreatic cancer.

CONCLUSIONS

Our findings therefore identify the miR-17-92 cluster as a functionally determining family of miRNAs in CSCs, and highlight the putative potential of developing modulators of this cluster to overcome drug resistance in pancreatic CSCs.

The Retinoblastoma Tumor Suppressor Protein (pRb)/E2 Promoter Binding Factor 1 (E2F1) Pathway as a Novel Mediator of TGFβ-induced Autophagy

TGFβ is a multifunctional cytokine that regulates cell proliferation, cell immortalization, and cell death, acting as a key homeostatic mediator in various cell types and tissues. Autophagy is a programmed mechanism that plays a pivotal role in controlling cell fate and, consequently, many physiological and pathological processes, including carcinogenesis. Although autophagy is often considered a pro-survival mechanism that renders cells viable in stressful conditions and thus might promote tumor growth, emerging evidence suggests that autophagy is also a tumor suppressor pathway. The relationship between TGFβ signaling and autophagy is context-dependent and remains unclear. TGFβ-mediated activation of autophagy has recently been suggested to contribute to the growth inhibitory effect of TGFβ in hepatocarcinoma cells. In the present study, we define a novel process of TGFβ-mediated autophagy in cancer cell lines of various origins. We found that autophagosome initiation and maturation by TGFβ is dependent on the retinoblastoma tumor suppressor protein/E2 promoter binding factor (pRb/E2F1) pathway, which we have previously established as a critical signaling axis leading to various TGFβ tumor suppressive effects. We further determined that TGFβ induces pRb/E2F1-dependent transcriptional activation of several autophagy-related genes. Together, our findings reveal that TGFβ induces autophagy through the pRb/E2F1 pathway and transcriptional activation of autophagy-related genes and further highlight the central relevance of the pRb/E2F1 pathway downstream of TGFβ signaling in tumor suppression.

Expression of CDKN1A/p21 and TGFBR2 in breast cancer and their prognostic significance

BACKGROUND

A new diagnostic and prognostic biomarker may be of value in cancer diseases. Our study aimed to evaluate the CDKN1A/p21 and TGFBR2 level measurable in a cohort of patients with breast cancer after mastectomy, and to confirm their suitability to serve as prognostic biomarkers of the cancer.

METHODS

The expression levels of CDKN1A/p21 and TGFBR2 were detected by reverse transcription-PCR (RT-PCR), western blot assay and immunohistochemical staining for 65 primary tumor samples and paired adjacent noncancerous breast tissues. Their relations to clinicopathologic parameters and to the prognosis of patients with breast cancer were analyzed.

RESULTS

We found the mRNA and protein expression levels of CDKN1A/p21 were significantly upregulated in breast cancer tissues compared with adjacent nontumorous breast tissues. Increased CDKN1A/p21 expression showed a significant correlation with larger tumor size (P=0.014), higher tumor dedifferentiation grade (P=0.021), lymph node metastasis (P=0.019) and a shorter disease-free survival (P=0.044). Contrarily, the expression levels of TGFBR2 mRNA and protein were significantly decreased in breast cancer tissues compared with adjacent nontumorous breast tissues. Underexpression of TGFBR2 in breast cancer was correlated with larger tumor size (P=0.034), lymph node metastasis (P=0.039) and a shorter disease-free survival (P=0.035). Statistical analysis suggested that there was no significant association between CDKN1A/p21 and TGFBR2 expression.

CONCLUSIONS

in summary, our results suggested that high CDKN1A/p21 and low TGFBR2 expression was closely correlated with adverse pathological parameters and poor prognosis in breast cancer. Both CDKN1A/p21 and TGFBR2 are presented as possible candidates for breast cancer biomarkers.

Soy Isoflavone Glycitin (4'-Hydroxy-6-Methoxyisoflavone-7-D-Glucoside) Promotes Human Dermal Fibroblast Cell Proliferation and Migration via TGF-β Signaling

Glycitin is a soy isoflavone that exhibits antioxidant, antiallergic, and anti-osteoporosis activities. We investigated the effects of glycitin on dermal fibroblast proliferation and migration. Treatment of primary dermal fibroblasts with glycitin increased cell proliferation and migration. In addition, treatment with 20 μM glycitin for 24 h induced the synthesis of collagen type I and type III at both the mRNA and protein levels. Fibronectin was also increased by 20% after treatment. Matrix metalloproteinase-1 collagenase was decreased in the media after 24-h incubation with glycitin, and the synthesis of transforming growth factor-beta (TGF-β) mRNA increased approximately twofold in cells following glycitin treatment. Phosphorylation of Smad2 and Smad3 increased after 1 h of glycitin treatment, and phosphorylation continued for 24 h. Furthermore, the phosphorylated form of AKT was increased in glycitin-treated cells after 3 h and remained higher for 24 h. Thus, glycitin treatment produces anti-aging effects including increased total collagen in the culture media, decreased elastase, and decreased β-galactosidase. Together, these results indicate that glycitin stimulates TGF-β secretion, and the subsequent autocrine actions of TGF-β induce proliferation of fibroblasts, ultimately protecting skin cells from aging and wrinkling.

The leukemia inhibitory factor (LIF) and p21 mediate the TGFβ tumor suppressive effects in human cutaneous melanoma

BACKGROUND

Cutaneous melanoma is the most lethal skin cancer and its incidence in developed countries has dramatically increased over the past decades. Localized tumors are easily treated by surgery, but advanced melanomas lack efficient treatment and are associated with very poor outcomes. Thus, understanding the processes underlying melanoma development and progression is critical. The Transforming Growth Factor beta (TGFβ) acts as a potent tumor suppressor in human melanoma, by inhibiting cell growth and preventing cellular migration and invasion.

METHODS

In this study, we aimed at elucidating the molecular mechanisms underlying TGFβ-mediated tumor suppression. Human cutaneous melanoma cell lines, derived from different patients, were used to assess for cell cycle analysis, apoptosis/caspase activity and cell migration. Techniques involved immunoblotting, immunohistochemistry, real time PCR and luciferase reporter assays.

RESULTS

We found the leukemia inhibitory factor (LIF) to be strongly up-regulated by TGFβ in melanoma cells, defining LIF as a novel TGFβ downstream target gene in cutaneous melanoma. Interestingly, we also showed that TGFβ-mediated LIF expression is required for TGFβ-induced cell cycle arrest and caspase-mediated apoptosis, as well as for TGFβ-mediated inhibition of cell migration. Moreover, we found that TGFβ-mediated LIF expression leads to activation of transcription of the cell cycle inhibitor p21 in a STAT3-dependent manner, and further showed that p21 is required for TGFβ/LIF-mediated cell cycle arrest and TGFβ-induced gene activation of several pro-apoptotic genes.

CONCLUSIONS

Together, our results define the LIF/p21 signaling cascade as a novel tumor suppressive-like pathway in melanoma, acting downstream of TGFβ to regulate cell cycle arrest and cell death, further highlight new potential therapeutic strategies for the treatment of cutaneous melanoma.

Single live cell TGF-β signalling imaging: breast cancer cell motility and migration is driven by sub-populations of cells with dynamic TGF-β-Smad3 activity

BACKGROUND

Metastasis is a process where only a small subset of cells is capable of successfully migrating to and propagating at secondary sites. TGF-β signalling is widely known for its role in cancer metastasis and is associated with cell migration in whole cell populations.

FINDINGS

We extend these findings by investigating the role of TGF-β signalling in promoting migration and motility by imaging the signalling activity in live, individual MDA-MB-231 cancer cells utilizing a novel Smad3 Td-Tomato reporter adenovirus. Here we find that not all MDA-MB-231 cancer cells have similar TGF-β mediated Smad3 transcription activity and display at least two distinct migratory populations. Importantly, Smad3 activity was significantly higher within migratory cells compared to non-migrated cells in wound healing and transwell assays. Furthermore, time-lapse experiments showed that MDA-MB-231 cells displaying Smad3 activity moved faster and a greater distance compared to cells not displaying Smad3 reporter activity. Interestingly, despite being more motile than cells with undetectable levels of Smad3 activity, high Smad3 activity was detrimental to cell motility compared to low and medium level of Smad3 activity.

CONCLUSIONS

We have developed a method enabling real-time visualization of TGF-β signalling in single live cells. Breast cancer cell motility and migration is driven by sub-populations of cells with dynamic TGF-β-Smad3 activity. Those sub-populations may be responsible for tumor invasion and metastasis.

Targeting the tumor microenvironment to enhance antitumor immune responses

The identification of tumor-specific antigens and the immune responses directed against them has instigated the development of therapies to enhance antitumor immune responses. Most of these cancer immunotherapies are administered systemically rather than directly to tumors. Nonetheless, numerous studies have demonstrated that intratumoral therapy is an attractive approach, both for immunization and immunomodulation purposes. Injection, recruitment and/or activation of antigen-presenting cells in the tumor nest have been extensively studied as strategies to cross-prime immune responses. Moreover, delivery of stimulatory cytokines, blockade of inhibitory cytokines and immune checkpoint blockade have been explored to restore immunological fitness at the tumor site. These tumor-targeted therapies have the potential to induce systemic immunity without the toxicity that is often associated with systemic treatments. We review the most promising intratumoral immunotherapies, how these affect systemic antitumor immunity such that disseminated tumor cells are eliminated, and which approaches have been proven successful in animal models and patients.

Breast cancer anti-estrogen resistance 3 inhibits transforming growth factor β/Smad signaling and associates with favorable breast cancer disease outcomes

INTRODUCTION

This study helps to define the implications of breast cancer anti-estrogen resistance 3 (BCAR3) in breast cancer and extends the current understanding of its molecular mechanism of action. BCAR3 has been shown to promote cell proliferation, migration and attachment to extracellular matrix components. However, in a cohort of metastatic breast cancer patients who received tamoxifen treatment, high BCAR3 mRNA levels were associated with favorable progression-free survival outcome. These results suggest that, besides its established roles, BCAR3 may have additional mechanisms of action that regulate breast cancer aggressive phenotype. In this study, we investigated whether BCAR3 is a novel antagonist of the canonical transforming growth factor β (TGFβ) pathway, which induces potent migration and invasion responses in breast cancer cells.

METHODS

We surveyed functional genomics databases for correlations between BCAR3 expression and disease outcomes of breast cancer patients. We also studied how BCAR3 could regulate the TGFβ/Smad signaling axis using Western blot analysis, coimmunoprecipitation and luciferase assays. In addition, we examined whether BCAR3 could modulate TGFβ-induced cell migration and invasion by using an automated imaging system and a confocal microscopy imaging-based matrix degradation assay, respectively.

RESULTS

Relatively low levels of BCAR3 expression in primary breast tumors correlate with poor distant metastasis-free survival and relapse-free survival outcomes. We also found a strong correlation between the loss of heterozygosity at BCAR3 gene alleles and lymph node invasion in human breast cancer, further suggesting a role for BCAR3 in preventing disease progression. In addition, we found BCAR3 to inhibit Smad activation, Smad-mediated gene transcription, Smad-dependent cell migration and matrix digestion in breast cancer cells. Furthermore, we found BCAR3 to be downregulated by TGFβ through proteasome degradation, thus defining a novel positive feedback loop mechanism downstream of the TGFβ/Smad signaling pathway.

CONCLUSION

BCAR3 is considered to be associated with aggressive breast cancer phenotypes. However, our results indicate that BCAR3 acts as a putative suppressor of breast cancer progression by inhibiting the prometastatic TGFβ/Smad signaling pathway in invasive breast tumors. These data provide new insights into BCAR3's molecular mechanism of action and highlight BCAR3 as a novel TGFβ/Smad antagonist in breast cancer.

Stage-dependent prognostic impact of molecular signatures in clear cell renal cell carcinoma

Purpose

To enhance prognostic information of protein biomarkers for clear cell renal cell carcinomas (ccRCCs), we analyzed them within prognostic groups of ccRCC harboring different tumor characteristics of this clinically and molecularly heterogeneous tumor entity.

Methods

Tissue microarrays from 145 patients with primary ccRCC were immunohistochemically analyzed for VHL (von Hippel-Lindau tumor suppressor), Ki67 (marker of proliferation 1), p53 (tumor protein p53), p21 (cyclin-dependent kinase inhibitor 1A), survivin (baculoviral IAP repeat containing 5), and UEA-1 (Ulex europaeus agglutinin I) to assess microvessel-density.

Results

When analyzing all patients, nuclear staining of Ki67 (hazard ratio [HR] 1.08, 95% confidence interval [CI] 1.04–1.12) and nuclear survivin (nS; HR 1.04, 95% CI 1.01–1.08) were significantly associated with disease-specific survival (DSS). In the cohort of patients with advanced localized or metastasized ccRCC, high staining of Ki67, p53 and nS predicted shorter DSS (Ki67: HR 1.07, 95% CI 1.02–1.11; p53: HR 1.05, 95% CI 1.01–1.09; nS: HR 1.08, 95% CI 1.02–1.14). In organ-confined ccRCC, patients with high p21-staining had a longer DSS (HR 0.96, 95% CI 0.92–0.99). In a multivariate model with stepwise backward elimination, tumor size and p21-staining showed a significant association with DSS in patients with “organ-confined” ccRCCs. The p21-staining increased the concordance index of tumor size from 0.75 to 0.78. In patients with “organ-confined” ccRCC, no disease-related deaths occurred in the group with p21-expression below the threshold of 32.5% p21-positive cells (log rank test: P=0.002).

Conclusion

The prognostic information of the studied protein biomarkers depended on anatomic tumor stages, which displayed different acquired biological tumor characteristics. Analysis of prognostic factors within different clinical ccRCC groups could help to enhance their prognostic power. The p21-staining was an independent prognostic factor and increased prognostic accuracy in a predictive model in “organ-confined” ccRCC.

The transcriptional regulators TAZ and YAP direct transforming growth factor β-induced tumorigenic phenotypes in breast cancer cells

Uncontrolled transforming growth factor-β (TGFβ) signaling promotes aggressive metastatic properties in late-stage breast cancers. However, how TGFβ-mediated cues are directed to induce tumorigenic events is poorly understood, particularly given that TGFβ has clear tumor suppressing activity in other contexts. Here, we demonstrate that the transcriptional regulators TAZ and YAP (TAZ/YAP), key effectors of the Hippo pathway, are necessary to promote and maintain TGFβ-induced tumorigenic phenotypes in breast cancer cells. Interactions between TAZ/YAP, TGFβ-activated SMAD2/3, and TEAD transcription factors reveal convergent roles for these factors in the nucleus. Genome-wide expression analyses indicate that TAZ/YAP, TEADs, and TGFβ-induced signals coordinate a specific pro-tumorigenic transcriptional program. Importantly, genes cooperatively regulated by TAZ/YAP, TEAD, and TGFβ, such as the novel targets NEGR1 and UCA1, are necessary for maintaining tumorigenic activity in metastatic breast cancer cells. Nuclear TAZ/YAP also cooperate with TGFβ signaling to promote phenotypic and transcriptional changes in nontumorigenic cells to overcome TGFβ-repressive effects. Our work thus identifies cross-talk between nuclear TAZ/YAP and TGFβ signaling in breast cancer cells, revealing novel insight into late-stage disease-driving mechanisms.

Sustained activation of SMAD3/SMAD4 by FOXM1 promotes TGF-β-dependent cancer metastasis

A key feature of TGF-β signaling activation in cancer cells is the sustained activation of SMAD complexes in the nucleus; however, the drivers of SMAD activation are poorly defined. Here, using human and mouse breast cancer cell lines, we found that oncogene forkhead box M1 (FOXM1) interacts with SMAD3 to sustain activation of the SMAD3/SMAD4 complex in the nucleus. FOXM1 prevented the E3 ubiquitin-protein ligase transcriptional intermediary factor 1 γ (TIF1γ) from binding SMAD3 and monoubiquitinating SMAD4, which stabilized the SMAD3/SMAD4 complex. Loss of FOXM1 abolished TGF-β-induced SMAD3/SMAD4 formation. Moreover, the interaction of FOXM1 and SMAD3 promoted TGF-β/SMAD3-mediated transcriptional activity and target gene expression. We found that FOXM1/SMAD3 interaction was required for TGF-β-induced breast cancer invasion, which was the result of SMAD3/SMAD4-dependent upregulation of the transcription factor SLUG. Importantly, the function of FOXM1 in TGF-β-induced invasion was not dependent on FOXM1's transcriptional activity. Knockdown of SMAD3 diminished FOXM1-induced metastasis. Furthermore, FOXM1 levels correlated with activated TGF-β signaling and metastasis in human breast cancer specimens. Together, our data indicate that FOXM1 promotes breast cancer metastasis by increasing nuclear retention of SMAD3 and identify crosstalk between FOXM1 and TGF-β/SMAD3 pathways. This study highlights the critical interaction of FOXM1 and SMAD3 for controlling TGF-β signaling during metastasis.

Panduratin A, a possible inhibitor in metastasized A549 cells through inhibition of NF-kappa B translocation and chemoinvasion

In the present study, we investigated the effects of panduratin A (PA), isolated from Boesenbergia rotunda, on apoptosis and chemoinvasion in A549 human non-small cell lung cancer cells. Activation of the executioner procaspase-3 by PA was found to be dose-dependent. Caspase-3 activity was significantly elevated at the 5 µg/mL level of PA treatment and progressed to a maximal level. However, no significant elevated level was detected on procaspase-8. These findings suggest that PA activated caspase-3 but not caspase-8. Numerous nuclei of PA treated A549 cells stained brightly by anti-cleaved PARP antibody through High Content Screening. This result further confirmed that PA induced apoptotic cell death was mediated through activation of caspase-3 and eventually led to PARP cleavage. Treatment of A549 cells with PA resulted in a strong inhibition of NF-κB activation, which was consistent with a decrease in nuclear levels of NF-κB/p65 and NF-κB/p50 and the elevation of p53 and p21. Besides that, we also showed that PA significantly inhibited the invasion of A549 cells in a dose-dependent manner through reducing the secretion of MMP-2 of A549 cells gelatin zymography assay. Our findings not only provide the effects of PA, but may also be important in the design of therapeutic protocols that involve targeting of either p53 or NF-κB.

Cyclin D1 cooperates with p21 to regulate TGFβ-mediated breast cancer cell migration and tumor local invasion

Introduction

Deregulation of the cell cycle machinery is often found in human cancers. Modulations in the cell cycle regulator function and expression result not only in proliferative advantages, but also lead to tumor progression and invasiveness of the cancer. In particular, cyclin D1 and p21 are often over-expressed in human cancers, correlating with high tumor grade, poor prognosis and increased metastasis. This prompted us to investigate the role of the cyclin D1/p21 signaling axis downstream of transforming growth factor beta (TGFβ) in breast cancer progression.

Methods

Cyclins mRNA and protein expressions were assessed by quantitative real-time PCR and Western blot in triple negative breast cancer cell lines. Co-localization and interaction between cyclin D1 and p21 were performed by immunocytochemistry and co-immunoprecipitation, respectively. Cell migration was assessed by wound healing and quantitative time-lapse imaging assays. In addition, the effects of cyclin D1 on cellular structure and actin organization were examined by staining with F-actin marker phalloidin and mesenchymal intermediate filament vimentin. Finally, a mammary fat pad xenograft mouse model was used to assess mammary tumor growth and local invasion.

Results

We found TGFβ to specifically up-regulate the expression of cyclin D1 in triple negative breast cancer cells. Induction of cyclin D1 is also required for TGFβ-mediated cell migration. Suppression of cyclin D1 expression not only resulted in a rounded and epithelial-like phenotype, but also prevented TGFβ-induced vimentin and F-actin co-localization at the cell edge as well as invadopodia formation. Furthermore, TGFβ promoted the nuclear co-localization and physical interaction between cyclin D1 and p21. The co-expression of cyclin D1 and p21 proteins are required for the initial steps of tumor development, as double knockdown of these two molecules prevented primary tumor formation in a Xenograft mouse model. Moreover, the in vivo studies indicated that locally advanced features of the invasive tumors, including skeletal muscle, mammary fat pad and lymphovascular invasion, as well as ulcerated skin, were attenuated in the absence of cyclin D1 and p21.

Conclusions

Thus, our findings highlight the cyclin D1/p21 signaling axis as a critical regulator of TGFβ-mediated tumor growth initiation and local tumor cell invasion, both in vitro and in vivo.

Progestin drives breast cancer growth by inducing p21(CIP1) expression through the assembly of a transcriptional complex among Stat3, progesterone receptor and ErbB-2

Cell cycle regulator p21(CIP1) has controversial biological effects in breast cancer since in spite of its role as cell cycle inhibitor and promoter of cellular senescence, it also induces cell proliferation and chemoteraphy resistance. We here explored the molecular mechanisms involved in progestin regulation of p21(CIP1) expression. We also investigated the biological effects of p21(CIP1) in breast cancer cells. We found that the synthetic progestin medroxyprogesterone acetate (MPA) upregulates p21(CIP1) protein expression via c-Src, signal transducer and activator of transcription 3 (Stat3) and ErbB-2 phosphorylation. Notably, we also found that ErbB-2 nuclear function plays a key role in MPA-induction of p21(CIP1) expression. Interestingly, we determined that progestin drives p21(CIP1) transcriptional activation via a novel nonclassical transcriptional mechanism in which progesterone receptor is recruited along with Stat3 and ErbB-2 to a Stat3 binding site at p21(CIP1) promoter. Our findings revealed that ErbB-2 functions as a coactivator of Stat3 in progestin induction of p21(CIP1) transcriptional activation. Furthermore, we demonstrated that blockage of p21(CIP1) expression strongly inhibited in vitro and in vivo progestin-induced breast cancer cell proliferation. These results further support the hypothesis that according to cell context and type of stimulus, p21(CIP1) is capable of inducing cell cycle progression. Moreover, we provided evidence that Stat3 and nuclear ErbB-2 are key players in progestin-induced p21(CIP1) regulation.

miR-211 promotes the progression of head and neck carcinomas by targeting TGFβRII

miR-211 up-regulation and transforming growth factor-β type II receptor (TGFβRII) down-regulation are associated with poor prognosis of head and neck squamous cell carcinoma (HNSCC). miR-211 directly targets TGFβRII with the miR-211-TGFβRII-c-Myc axis promoting HNSCC progression. An inverse correlation of miR-211 and TGFβRII expression was found in metastatic HNSCC samples. After 4-nitroquinoline 1-oxide induction, more severe epithelial tumorigenesis was detected on K14-miR-211 transgenic mouse dorsal tongues. Human metastatic lesions and mouse tongue tumors showed increased nuclear c-Myc expression. A novel role for miR-211 in the regulation of TGFβRII and c-Myc during tumorigenesis being revealed should help to develop anti-HNSCC therapies.

Activin and TGFβ regulate expression of the microRNA-181 family to promote cell migration and invasion in breast cancer cells

MicroRNA-181 (miR-181) is a multifaceted miRNA that has been implicated in many cellular processes such as cell fate determination and cellular invasion. While miR-181 is often overexpressed in human tumors, a direct role for this miRNA in breast cancer progression has not yet been characterized. In this study, we found this miRNA to be regulated by both activin and TGFβ. While we found no effect of miR-181 modulation on activin/TGFβ-mediated tumor suppression, our data clearly indicate that miR-181 plays a critical and prominent role downstream of two growth factors, in mediating their pro-migratory and pro-invasive effects in breast cancer cells miR-181 acts as a metastamir in breast cancer. Thus, our findings define a novel role for miR-181 downstream of activin/TGFβ in regulating their tumor promoting functions. Having defined miR-181 as a critical regulator of tumor progression in vitro, our results thus, highlight miR-181 as an important potential therapeutic target in breast cancer.

MicroRNA-584 and the protein phosphatase and actin regulator 1 (PHACTR1), a new signaling route through which transforming growth factor-β Mediates the migration and actin dynamics of breast cancer cells

TGF-β plays an important role in breast cancer progression as a prometastatic factor, notably through enhancement of cell migration. It is becoming clear that microRNAs, a new class of small regulatory molecules, also play crucial roles in mediating tumor formation and progression. We found TGF-β to down-regulate the expression of the microRNA miR-584 in breast cancer cells. Furthermore, we identified PHACTR1, an actin-binding protein, to be positively regulated by TGF-β in a miR-584-dependent manner. Moreover, we found TGF-β-mediated down-regulation of miR-584 and increased expression of PHACTR1 to be required for TGF-β-induced cell migration of breast cancer cells. Indeed, both overexpression of miR-584 and knockdown of PHACTR1 resulted in a drastic reorganization of the actin cytoskeleton and reduced TGF-β-induced cell migration. Our data highlight a novel signaling route whereby TGF-β silences the expression of miR-584, resulting in enhanced PHACTR1 expression, and further leading to actin rearrangement and breast cancer cell migration.

Cyclic AMP enhances TGFβ responses of breast cancer cells by upregulating TGFβ receptor I expression

Cellular functions are regulated by complex networks of many different signaling pathways. The TGFβ and cAMP pathways are of particular importance in tumor progression. We analyzed the cross-talk between these pathways in breast cancer cells in 2D and 3D cultures. We found that cAMP potentiated TGFβ-dependent gene expression by enhancing Smad3 phosphorylation. Higher levels of total Smad3, as observed in 3D-cultured cells, blocked this effect. Two Smad3 regulating proteins, YAP (Yes-associated protein) and TβRI (TGFβ receptor 1), were responsive to cAMP. While YAP had little effect on TGFβ-dependent expression and Smad3 phosphorylation, a constitutively active form of TβRI mimicked the cAMP effect on TGFβ signaling. In 3D-cultured cells, which show much higher levels of TβRI and cAMP, TβRI was unresponsive to cAMP. Upregulation of TβRI expression by cAMP was dependent on transcription. A proximal TβRI promoter fragment was moderately, but significantly activated by cAMP suggesting that cAMP increases TβRI expression at least partially by activating TβRI transcription. Neither the cAMP-responsive element binding protein (CREB) nor the TβRI-regulating transcription factor Six1 was required for the cAMP effect. An inhibitor of histone deacetylases alone or together with cAMP increased TβRI expression by a similar extent as cAMP alone suggesting that cAMP may exert its effect by interfering with histone acetylation. Along with an additive stimulatory effect of cAMP and TGFβ on p21 expression an additive inhibitory effect of these agents on proliferation was observed. Finally, we show that mesenchymal stem cells that interact with breast cancer cells can simultaneously activate the cAMP and TGFβ pathways. In summary, these data suggest that combined effects of cAMP and TGFβ, as e.g. induced by mesenchymal stem cells, involve the upregulation of TβRI expression on the transcriptional level, likely due to changes in histone acetylation. As a consequence, cancer cell functions such as proliferation are affected.

The Dual Role of TGFβ in Human Cancer: From Tumor Suppression to Cancer Metastasis

The transforming growth factor-beta (TGFβ) superfamily encompasses widespread and evolutionarily conserved polypeptide growth factors that regulate and orchestrate growth and differentiation in all cell types and tissues. While they regulate asymmetric cell division and cell fate determination during early development and embryogenesis, TGFβ family members play a major regulatory role in hormonal and immune responses, cell growth, cell death and cell immortalization, bone formation, tissue remodeling and repair, and erythropoiesis throughout adult life. The biological and physiological functions of TGFβ, the founding member of this family, and its receptors are of central importance to human diseases, particularly cancer. By regulating cell growth, death, and immortalization, TGFβ signaling pathways exert tumor suppressor effects in normal cells and early carcinomas. Thus, it is not surprising that a high number of human tumors arise due to mutations or deletions in the genes coding for the various TGFβ signaling components. As tumors develop and progress, these protective and cytostatic effects of TGFβ are often lost. TGFβ signaling then switches to promote cancer progression, invasion, and tumor metastasis. The molecular mechanisms underlying this dual role of TGFβ in human cancer will be discussed in depth in this paper, and it will highlight the challenge and importance of developing novel therapeutic strategies specifically aimed at blocking the prometastatic arm of the TGFβ signaling pathway without affecting its tumor suppressive effects.