Transforming growth factor-β signaling in cancer invasion and metastasis

TGF-β and TNF-α interaction promotes the expression of MMP-9 through H3K36 dimethylation: implications in breast cancer metastasis

Increased MMP-9 expression in the tumor microenvironment (TME) plays a crucial role in the extracellular matrix remodeling to facilitate cancer invasion and metastasis. However, the mechanism of MMP-9 upregulation in TME remains elusive. Since TGF-β and TNF-α levels are elevated in TME, we asked whether these two agents interacted to induce/augment MMP-9 expression. Using a well-established MDA-MB-231 breast cancer model, we found that the synergy between TGF-β and TNF-α led to MMP-9 upregulation at the transcriptional and translational levels, compared to treatments with each agent alone. Our in vitro findings are corroborated by co-expression of elevated MMP-9 with TGF-β and TNF-α in human breast cancer tissues. Mechanistically, we found that the MMP-9 upregulation driven by TGF-β/TNF-α cooperativity was attenuated by selective inhibition of the TGF-βRI/Smad3 pathway. Comparable outcomes were observed upon inhibition of TGF-β-induced phosphorylation of Smad2/3 and p38. As expected, the cells defective in Smad2/3 or p38-mediated signaling did not exhibit this synergistic induction of MMP-9. Importantly, the inhibition of histone methylation but not acetylation dampened the synergistic MMP-9 expression. Histone modification profiling further identified the H3K36me2 as an epigenetic regulatory mark of this synergy. Moreover, TGF-β/TNF-α co-stimulation led to increased levels of the transcriptionally permissive dimethylation mark at H3K36 in the MMP-9 promoter. Comparable outcomes were noted in cells deficient in NSD2 histone methyltransferase. In conclusion, our findings support a cooperativity model in which TGF-β could amplify the TNF-α-mediated MMP-9 production via chromatin remodeling and facilitate breast cancer invasion and metastasis.

Diosmetin: A dietary flavone as modulator of signaling pathways in cancer progression

Flavonoids, constituting the most extensive category of polyphenols, founds in a variety of plants and comprise over 9000 compounds. Diosmetin, O-methylated flavone (3',5,7-trihydroxy-4'-methoxyflavone) of flavonoid aglycone diosmin have witnessed a significant surge in recent years. Many studies showed that flavonoids induced cytotoxicity in different organ specific cancer types. Thus, current review evaluates the anticancer potential of diosmetin and shed light on its mechanism of action such as cell cycle regulation, apoptosis via both intrinsic and extrinsic pathway, autophagy and tumour progression and metastasis. It also provides comprehensive analysis of different cancer targets and their role in breast, colon, hepatic, gliomas, leukemia, lung, prostate and skin cancer. Combination studies of diosmetin to improve drug sensitivity and reduce toxicity towards normal cells has been also discussed. Besides, in vitro studies, present review also discuss the anticancer potential of diosmetin on xenograft mice model. Different natural sources of diosmetin, limitations, pharmacokinetic analysis and toxicity study also summarized in current review. The emphasis on enhancing solubility and permeability for clinical utility has been thoroughly highlighted with particular attention given to the utilization of nano formulations to overcome existing barriers. At last, in-depth analysis of current challenges and a forward-looking perspective deliberated to address the existing gaps and position it as a promising lead compound for clinical applications in cancer treatment. This discussion is boosted by diosmetin's potential anticancer properties on different cancers, makes valuable candidates in the ongoing quest for effective therapeutic interventions against cancer.

A Novel TGF-β-Related Signature for Predicting Prognosis, Tumor Microenvironment, and Therapeutic Response in Colorectal Cancer

The transforming growth factor beta (TGF-β) signaling plays a critical role in immune evasion and tumor progression. However, its modulatory influences on prognosis, tumor microenvironment (TME), and therapeutic efficacy remain unknown in colorectal cancer (CRC). We summarized TGF-β-related genes and comprehensively estimated their expression pattern in 2142 CRC samples from 9 datasets. Two distinct cluster patterns were divided and biological characteristics of each pattern were further analyzed. Then, to quantify the TGF-β cluster pattern of individual CRC patient, we generated the TGF-β score (TGFBscore) model based on TGF-β cluster pattern-relevant differentially expressed genes (DEGs). Subsequently, we conducted correlation analysis for TGFBscore and clinical prognosis, consensus molecular subtypes (CMSs), TME characteristics, liver metastasis, drug response, and immunotherapeutic efficacy in CRC. We illustrated transcriptional and genetic alterations of TGF-β-relevant genes, which were closely linked with carcinogenic pathways. We identified two different TGF-β cluster patterns, characterized by a high and a low TGFBscore. The TGFBscore-high group was significantly linked with worse patient survival, epithelial-mesenchymal transition (EMT) activation, liver metastasis tendency, and the infiltration of immunosuppressive cells (regulatory T cells [Tregs], M2 macrophages, cancer-associated fibroblasts [CAFs], and myeloid-derived suppressor cells [MDSCs]), while the TGFBscore-low group was linked with a survival advantage, epithelial phenotype, early CRC staging, and the infiltration of immune-activated cells (B cell, CD4 T cell, natural killer T [NKT] cell, and T helper 1 [Th1] cell). In terms of predicting drug response, TGFBscore negatively correlated (sensitive to TGFBscore-high group) with drugs targeting PI3K/mTOR, JNK and p38, RTK signaling pathways, and positively correlated (sensitive to TGFBscore-low group) with drugs targeting EGFR signaling pathway. Also, TGFBscore could predict the efficacy of different anti-tumor therapies. TGFBscore-low patients might benefit more from anti-PDL1 immunotherapy, adjuvant chemotherapy (ACT), and ERBB targeted therapy, whereas TGFBscore-high patients might benefit more from antiangiogenic targeted therapy. Our study constructed a novel TGF-β scoring model that could predict prognosis, liver metastasis tendency, and TME characteristics for CRC patients. More importantly, this work emphasizes the potential clinical utility of TGFBscore in evaluating the efficacy of chemotherapy, targeted therapy, and immunotherapy, guiding individualized precision treatment in CRC.

Inhibition of TGF-β signaling, invasion, and growth of cutaneous squamous cell carcinoma by PLX8394

Cutaneous squamous cell carcinoma (cSCC) is the most common metastatic skin cancer. The prognosis of patients with metastatic cSCC is poor emphasizing the need for new therapies. We have previously reported that the activation of Ras/MEK/ERK1/2 and transforming growth factor β (TGF-β)/Smad2 signaling in transformed keratinocytes and cSCC cells leads to increased accumulation of laminin-332 and accelerated invasion. Here, we show that the next-generation B-Raf inhibitor PLX8394 blocks TGF-β signaling in ras-transformed metastatic epidermal keratinocytes (RT3 cells) harboring wild-type B-Raf and hyperactive Ras. PLX8394 decreased phosphorylation of TGF-β receptor II and Smad2, as well as p38 activity, MMP-1 and MMP-13 synthesis, and laminin-332 accumulation. PLX8394 significantly inhibited the growth of human cSCC tumors and in vivo collagen degradation in xenograft model. In conclusion, our data indicate that PLX8394 inhibits several serine-threonine kinases in malignantly transformed human keratinocytes and cSCC cells and inhibits cSCC invasion and tumor growth in vitro and in vivo. We identify PLX8394 as a potential therapeutic compound for advanced human cSCC.

Transforming Growth Factor Beta and Epithelial to Mesenchymal Transition Alter Homologous Recombination Repair Gene Expression and Sensitize BRCA Wild-Type Ovarian Cancer Cells to Olaparib

Epithelial ovarian cancer (EOC) remains the most lethal gynecologic malignancy, largely due to metastasis and drug resistant recurrences. Fifteen percent of ovarian tumors carry mutations in BRCA1 or BRCA2, rendering them vulnerable to treatment with PARP inhibitors such as olaparib. Recent studies have shown that TGFβ can induce "BRCAness" in BRCA wild-type cancer cells. Given that TGFβ is a known driver of epithelial to mesenchymal transition (EMT), and the connection between EMT and metastatic spread in EOC and other cancers, we asked if TGFβ and EMT alter the susceptibility of EOC to PARP inhibition. Epithelial EOC cells were transiently treated with soluble TGFβ, and their clonogenic potential, expression, and function of EMT and DNA repair genes, and response to PARP inhibitors compared with untreated controls. A second epithelial cell line was compared to its mesenchymal derivative for EMT and DNA repair gene expression and drug responses. We found that TGFβ and EMT resulted in the downregulation of genes responsible for homologous recombination (HR) and sensitized cells to olaparib. HR efficiency was reduced in a dose-dependent manner. Furthermore, mesenchymal cells displayed sensitivity to olaparib, cisplatin, and the DNA-PK inhibitor Nu-7441. Therefore, the treatment of disseminated, mesenchymal tumors may represent an opportunity to expand the clinical utility of PARP inhibitors and similar agents.

Effects of CCN6 overexpression on the cell motility and activation of p38/bone morphogenetic protein signaling pathways in pancreatic cancer cells

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive cancer types that is highly resistant to conventional treatments, such as chemotherapy and radiotherapy. As the demand for more effective therapeutics for PDAC treatment increases, various approaches have been studied to develop novel targets. The cellular communication network (CCN) family is a matricellular protein that modulates various cellular functions, including cell adhesion, proliferation, migration, and invasiveness. Despite this, little is known about the role of CCN6 in PDAC. The current study investigated the role of CCN6 in PDAC by generating CCN6-overexpressing PANC-1 cells (PANC-1-CCN6) by infecting lentivirus particles containing CCN6. PANC-1-CCN6 induces cell viability and tumorigenesis than PANC-1 cells with empty vector (control). The PANC-1-CCN6 formed more colonies, and the size of spheroids increased compared to the control. The upregulation of CCN6 enhances the expression of bone morphogenetic proteins (BMPs) genes and the upregulation of p38 mitogen-activated protein kinases (MAPKs). In PANC-1-CCN6 cells, the levels of N-cadherin, VEGF, and Snail expression were higher than the control, while E-cadherin expression was lower, which is associated with upregulation of epithelial-to-mesenchymal transition (EMT). Consistent with the changes in EMT-related proteins in PANC-1-CCN6, the migratory ability and invasiveness were enhanced in PANC-1-CCN6. Xenografted PANC-1-CCN6 in immunocompromised mice exhibited accelerated tumor growth than the control group. In immunohistochemistry (IHC), the PANC-1-CCN6 xenografted tumor showed an increased positive area of PCNA and Ki-67 than the control. These results suggest that CCN6 plays a tumorigenic role and induces the metastatic potential by the p38 MAPK and BMPs signaling pathways. Although the role of CCN6 has been introduced as an antitumor factor, there was evidence of CCN6 acting to cause tumorigenesis and invasion in PANC-1.

Proteolytic modulation of tumor microenvironment signals during cancer progression

Under normal conditions, the cellular microenvironment is optimized for the proper functioning of the tissues and organs. Cells recognize and communicate with the surrounding cells and extracellular matrix to maintain homeostasis. When cancer arises, the cellular microenvironment is modified to optimize its malignant growth, evading the host immune system and finding ways to invade and metastasize to other organs. One means is a proteolytic modification of the microenvironment and the signaling molecules. It is now well accepted that cancer progression relies on not only the performance of cancer cells but also the surrounding microenvironment. This mini-review discusses the current understanding of the proteolytic modification of the microenvironment signals during cancer progression.

Low-Dose-Rate Radiation-Induced Secretion of TGF-β3 Together with an Activator in Small Extracellular Vesicles Modifies Low-Dose Hyper-Radiosensitivity through ALK1 Binding

Hyper-radiosensitivity (HRS) is the increased sensitivity to low doses of ionizing radiation observed in most cell lines. We previously demonstrated that HRS is permanently abolished in cells irradiated at a low dose rate (LDR), in a mechanism dependent on transforming growth factor β3 (TGF-β3). In this study, we aimed to elucidate the activation and receptor binding of TGF-β3 in this mechanism. T-47D cells were pretreated with inhibitors of potential receptors and activators of TGF-β3, along with addition of small extracellular vesicles (sEVs) from LDR primed cells, before their radiosensitivity was assessed by the clonogenic assay. The protein content of sEVs from LDR primed cells was analyzed with mass spectrometry. Our results show that sEVs contain TGF-β3 regardless of priming status, but only sEVs from LDR primed cells remove HRS in reporter cells. Inhibition of the matrix metalloproteinase (MMP) family prevents removal of HRS, suggesting an MMP-dependent activation of TGF-β3 in the LDR primed cells. We demonstrate a functional interaction between TGF-β3 and activin receptor like kinase 1 (ALK1) by showing that TGF-β3 removes HRS through ALK1 binding, independent of ALK5 and TGF-βRII. These results are an important contribution to a more comprehensive understanding of the mechanism behind TGF-β3 mediated removal of HRS.

TGF-β/IL-7 Chimeric Switch Receptor-Expressing CAR-T Cells Inhibit Recurrence of CD19-Positive B Cell Lymphoma

Chimeric antigen receptor (CAR)-T cells are effective in the treatment of hematologic malignancies but have shown limited efficacy against solid tumors. Here, we demonstrated an approach to inhibit recurrence of B cell lymphoma by co-expressing both a human anti-CD19-specific single-chain variable fragment (scFv) CAR (CD19 CAR) and a TGF-β/IL-7 chimeric switch receptor (tTRII-I7R) in T cells (CD19 CAR-tTRII-I7R-T cells). The tTRII-I7R was designed to convert immunosuppressive TGF-β signaling into immune-activating IL-7 signaling. The effect of TGF-β on CD19 CAR-tTRII-I7R-T cells was assessed by western blotting. Target-specific killing by CD19 CAR-tTRII-I7R-T cells was evaluated by Eu-TDA assay. Daudi tumor-bearing NSG (NOD/SCID/IL2Rγ^-/-) mice were treated with CD19 CAR-tTRII-I7R-T cells to analyze the in vivo anti-tumor effect. In vitro, CD19 CAR-tTRII-I7R-T cells had a lower level of phosphorylated SMAD2 and a higher level of target-specific cytotoxicity than controls in the presence of rhTGF-β1. In the animal model, the overall survival and recurrence-free survival of mice that received CD19 CAR-tTRII-I7R-T cells were significantly longer than in control mice. These findings strongly suggest that CD19 CAR-tTRII-I7R-T cell therapy provides a new strategy for long-lasting, TGF-β-resistant anti-tumor effects against B cell lymphoma, which may lead ultimately to increased clinical efficacy.

Crosstalk Between Tumor-Associated Microglia/Macrophages and CD8-Positive T Cells Plays a Key Role in Glioblastoma

Glioblastoma is considered to be the most malignant disease of the central nervous system, and it is often associated with poor survival. The immune microenvironment plays a key role in the development and treatment of glioblastoma. Among the different types of immune cells, tumor-associated microglia/macrophages (TAM/Ms) and CD8-positive (CD8+) T cells are the predominant immune cells, as well as the most active ones. Current studies have suggested that interaction between TAM/Ms and CD8+ T cells have numerous potential targets that will allow them to overcome malignancy in glioblastoma. In this review, we summarize the mechanism and function of TAM/Ms and CD8+ T cells involved in glioblastoma, as well as update on the relationship and crosstalk between these two cell types, to determine whether this association alters the immune status during glioblastoma development and affects optimal treatment. We focus on the molecular factors that are crucial to this interaction, and the role that this crosstalk plays in the biological processes underlying glioblastoma treatment, particularly with regard to immune therapy. We also discuss novel therapeutic targets that can aid in resolving reticular connections between TAM/Ms and CD8+ T cells, including depletion and reprogramming TAM/Ms and novel TAM/Ms-CD8+ T cell cofactors with potential translational usage. In addition, we highlight the challenges and discuss future perspectives of this crosstalk between TAM/Ms and CD8+ T cells.

Identification of miR-203a, mir-10a, and miR-194 as predictors for risk of lymphovascular invasion in head and neck cancers

Lymphovascular invasion (LVI) is an important prognostic indicator of lymph node metastasis and disease aggressiveness but clear molecular mechanisms mediating this in head and neck cancers (HNSC) remain undefined. To identify important microRNAs (miRNAs) in HNSC that associate with and are also predictive of increased risk of LVI, we used a combination of clustering algorithms, multiple regression analyses and machine learning approaches and analyzed miRNA expression profiles in the TCGA HNSC database. As the first step, we identified miRNAs with increased association with LVI as a binary variable. In order to determine whether the identified miRNAs would show functional clusters that are also indicative of increased risk for LVI, we carried out unsupervised as well as supervised clustering. Our results identified distinct clusters of miRNAs that are predictive of increased LVI. We further refined these findings using a Random forest approach, and miR-203a-3p, mir-10a-5p, and miR-194-5p to be most strongly associated with LVI. Pathway enrichment analysis showed these miRNAs targeted genes involved in Hippo signaling and fatty acid oxidation pathways that are mediators of lymph node metastasis. Specific association was also identified between the miRNAs associated with LVI and expression of several lymphangiogenic genes that could be critical for determination of therapeutic strategies.

A cytokine in turmoil: Transforming growth factor beta in cancer

Cancer remains one of the debilitating health threats to mankind in view of its incurable nature. Many factors are complicit in the initiation, progression and establishment of cancers. Early detection of cancer is the only window of hope that allows for appreciable management and possible limited survival. However, understanding of cancer biology and knowledge of the key factors that interplay at multi-level in the initiation and progression of cancer may hold possible avenues for cancer treatment and management. In particular, dysregulation of growth factor signaling such as that of transforming growth factor beta (TGF-β) and its downstream mediators play key roles in various cancer subtypes. Expanded understanding of the context/cell type-dependent roles of TGF-β and its downstream signaling mediators in cancer may provide leads for cancer pharmacotherapy. Reliable information contained in original articles, reviews, mini-reviews and expert opinions on TGF-β, cancer and the specific roles of TGF-β signaling in various cancer subtypes were retrieved from major scientific data bases including PubMed, Scopus, Medline, Web of Science core collections just to mention but a sample by using the following search terms: TGF-β in cancer, TGF-β and colorectal cancer, TGF-β and brain cancer, TGF-β in cancer initiation, TGF-β and cell proliferation, TGF-β and cell invasion, and TGF-β-based cancer therapy. Retrieved information and reports were carefully examined, contextualized and synchronized into a coherent scientific content to highlight the multiple roles of TGF-β signaling in normal and cancerous cells. From a conceptual standpoint, development of pharmacologically active agents that exert non-specific inhibitory effects on TGF-β signaling on various cell types will undoubtedly lead to a plethora of serious side effects in view of the multi-functionality and pleiotropic nature of TGF-β. Such non-specific targeting of TGF-β could derail any beneficial therapeutic intention associated with TGF-β-based therapy. However, development of pharmacologically active agents designed specifically to target TGF-β signaling in cancer cells may improve cancer pharmacotherapy. Similarly, specific targeting of downstream mediators of TGF-β such as TGF-β type 1 and II receptors (TβRI and TβRII), receptor-mediated Smads, mitogen activated protein kinase (MAPK) and importing proteins in cancer cells may be crucial for cancer pharmacotherapy.

The DDX39B/FUT3/TGFβR-I axis promotes tumor metastasis and EMT in colorectal cancer

DDX39B is a member of the DEAD box (DDX) RNA helicase family required for nearly all cellular RNA metabolic processes. The exact role and potential molecular mechanism of DDX39B in the progression of human colorectal cancer (CRC) remain to be investigated. In the present study, we demonstrate that DDX39B expression is higher in CRC tissues than in adjacent normal tissues. Gain- and loss-of-function assays revealed that DDX39B facilitates CRC metastasis in vivo and in vitro. Mechanistically, RNA-sequencing (RNA-seq) and RNA-binding protein immunoprecipitation-sequencing (RIP-seq) showed that DDX39B binds directly to the FUT3 pre-mRNA and upregulates FUT3 expression. Splicing experiments in vitro using a Minigene assay confirmed that DDX39B promotes FUT3 pre-mRNA splicing. A nuclear and cytoplasmic RNA separation assay indicates that DDX39B enhances the mRNA export of FUT3. Upregulation of FUT3 accelerates the fucosylation of TGFβR-I, which activates the TGFβ signaling pathway and eventually drives the epithelial–mesenchymal transition (EMT) program and contributes to CRC progression. These findings not only provide new insight into the role of DDX39B in mRNA splicing and export as well as in tumorigenesis, but also shed light on the effects of aberrant fucosylation on CRC progression.

Matrix metalloproteinases in keratinocyte carcinomas

The incidence of cutaneous keratinocyte-derived cancers is increasing globally. Basal cell carcinoma (BCC) is the most common malignancy worldwide, and cutaneous squamous cell carcinoma (cSCC) is the most common metastatic skin cancer. BCC can be classified into subtypes based on the histology, and these subtypes are classified further into low- and high-risk tumors. There is an increasing need to identify new therapeutic strategies for the treatment of unresectable and metastatic cSCC, and for aggressive BCC variants such as infiltrating, basosquamous or morpheaform BCCs. The most important risk factor for BCC and cSCC is solar UV radiation, which causes genetic and epigenetic alterations in keratinocytes. Similar gene mutations are noted already in sun-exposed normal skin emphasizing the role of the alterations in the tumor microenvironment in the progression of cSCC. Early events in cSCC progression are alterations in the composition of basement membrane and dermal extracellular matrix induced by influx of microbes, inflammatory cells and activated stromal fibroblasts. Activated fibroblasts promote inflammation and produce growth factors and proteolytic enzymes, including matrix metalloproteinases (MMPs). Transforming growth factor-β produced by tumor cells and fibroblasts induces the expression of MMPs by cSCC cells and promotes their invasion. Fibroblast-derived keratinocyte growth factor suppresses the malignant phenotype of cSCC cells by inhibiting the expression of several MMPs. These findings emphasize the importance of interplay of tumor and stromal cells in the progression of cSCC and BCC and suggest tumor microenvironment as a therapeutic target in cSCC and aggressive subtypes of BCC.

Regulatory T Cells: Barriers of Immune Infiltration Into the Tumor Microenvironment

Regulatory T cells (T_regs) are key immunosuppressive cells that promote tumor growth by hindering the effector immune response. T_regs utilize multiple suppressive mechanisms to inhibit pro-inflammatory responses within the tumor microenvironment (TME) by inhibition of effector function and immune cell migration, secretion of inhibitory cytokines, metabolic disruption and promotion of metastasis. In turn, T_regs are being targeted in the clinic either alone or in combination with other immunotherapies, in efforts to overcome the immunosuppressive TME and increase anti-tumor effects. However, it is now appreciated that T_regs not only suppress cells intratumorally via direct engagement, but also serve as key interactors in the peritumor, stroma, vasculature and lymphatics to limit anti-tumor immune responses prior to tumor infiltration. We will review the suppressive mechanisms that T_regs utilize to alter immune and non-immune cells outside and within the TME and discuss how these mechanisms collectively allow T_regs to create and promote a physical and biological barrier, resulting in an immune-excluded or limited tumor microenvironment.

TGFβ-Directed Therapeutics: 2020

The transforming growth factor-beta (TGFβ) pathway is essential during embryo development and in maintaining normal homeostasis. During malignancy, the TGFβ pathway is co-opted by the tumor to increase fibrotic stroma, to promote epithelial to mesenchymal transition increasing metastasis and producing an immune-suppressed microenvironment which protects the tumor from recognition by the immune system. Compelling preclinical data demonstrate the therapeutic potential of blocking TGFβ function in cancer. However, the TGFβ pathway cannot be described as a driver of malignant disease. Two small molecule kinase inhibitors which block the serine-threonine kinase activity of TGFβRI on TGFβRII, a pan-TGFβ neutralizing antibody, a TGFβ trap, a TGFβ antisense agent, an antibody which stabilizes the latent complex of TGFβ and a fusion protein which neutralizes TGFβ and binds PD-L1 are in clinical development. The challenge is how to most effectively incorporate blocking TGFβ activity alone and in combination with other therapeutics to improve treatment outcome.

Signaling pathways and microRNAs, the orchestrators of NANOG activity during cancer induction

Cancer stem cells (CSCs) are a small part of cancer cells inside the tumor that have similar characteristics to normal stem cells. CSCs stimulate tumor initiation and progression in a variety of cancers. Several transcription factors such as NANOG, SOX2, and OCT4 maintain the characteristics of CSCs and their upregulation is seen in many malignancies resulting in increased metastasis, invasion, and recurrence. Among these factors, NANOG plays an important role in regulating the self-renewal and pluripotency of CSCs and the clinical significance of NANOG has been suggested as a marker of CSCs in many cancers. The up and down-regulation of NANOG is associated with several important signaling pathways, including JAK/STAT, Wnt/β-catenin, Notch, TGF-β, Hedgehog, and several microRNAs (miRNAs). In this review, we will investigate the function of NANOG in CSCs and the molecular mechanism of its regulation by signaling pathways and miRNAs. We will also investigate targeting NANOG with different techniques, which is a promising treatment strategy for cancer treatment.

Aluminum exposure promotes the metastatic proclivity of human colorectal cancer cells through matrix metalloproteinases and the TGF-β/Smad signaling pathway

Human exposure to aluminum (Al) mainly occurs through food intake. However, influences of Al on the gastrointestinal tract have been rarely reported. In particular, the effect of Al on the metastasis and angiogenesis of colorectal cancer cells has not been studied. Thus, we investigated the effect of Al on the metastatic proclivity using the human colorectal cancer cell line, HT-29. Cells were exposed to 1-16 mM AlCl₃ for 3-72 h. The effects of AlCl₃ on HT-29 cells for migration/invasion/adhesion, and metastasis-associated protein and gene expression were evaluated. AlCl₃ promoted cell migration and invasion, whereas it suppressed cell adhesion. AlCl₃-exposed cells showed decreased E-cadherin and increased vimentin and Snail. AlCl₃ increased transforming growth factor-beta (TGF-β) mRNA expression and Smad2/3 nuclear translocation. AlCl₃-treated cells had a higher mRNA expression of matrix metalloproteinase (MMP)-7 and -9 than the control. Particularly, AlCl₃-treated HT-29 cells promoted the angiogenesis of endothelial cells via increasing the secretion of vascular endothelial growth factor. Taken together, AlCl₃ can promote the metastatic proclivity of colorectal cancer cells through MMP-7, -9, and TGF-β/Smad2/3 pathway. Our data suggest that Al exposure of the gastrointestinal tract may be a risk factor for metastasis initiation in colorectal cancer cells.

Tumor Development and Angiogenesis in Adult Brain Tumor: Glioblastoma

Angiogenesis is the growth of new capillaries from the preexisting blood vessels. Glioblastoma (GBM) tumors are highly vascularized tumors, and glioma growth depends on the formation of new blood vessels. Angiogenesis is a complex process involving proliferation, migration, and differentiation of vascular endothelial cells (ECs) under the stimulation of specific signals. It is controlled by the balance between its promoting and inhibiting factors. Various angiogenic factors and genes have been identified that stimulate glioma angiogenesis. Therefore, attention has been directed to anti-angiogenesis therapy in which glioma proliferation is inhibited by inhibiting the formation of new tumor vessels using angiogenesis inhibitory factors and drugs. Here, in this review, we highlight and summarize the various molecular mediators that regulate GBM angiogenesis with focus on recent clinical research on the potential of exploiting angiogenic pathways as a strategy in the treatment of GBM patients.

TGF-β1 activates RSC96 Schwann cells migration and invasion through MMP-2 and MMP-9 activities

Following peripheral nerve injury, remnant Schwann cells adopt a migratory phenotype and remodel the extracellular matrix allowing axonal regrowth. Although much evidence has demonstrated that TGF-β1 promotes glioma cell motility and induces the expression of extracellular matrix proteins, the effects of TGF-β1 on Schwann cell migration has not yet been studied. We therefore investigated the cellular effects and the signal transduction pathways evoked by TGF-β1 in rattus norvegicus neuronal Schwann RSC96 cell. TGF-β1 significantly increased migration and invasion of Schwann cells assessed by the wound-healing assay and by cell invasion assay. TGF-β1-enhanced migration/invasion was blocked by inhibition of MMP-2 and MMP-9. Consistently, by real-time and western blot analyses, we demonstrated that TGF-β1 increased MMP-2 and MMP-9 mRNA and protein levels. TGF-β1 also increased MMPs activities in cell growth medium, as shown by gelatin zymography. The selective TGF-β Type I receptor inhibitor SB431542 completely abrogated any effects by TGF-β1. Indeed, TGF-β1 Type I receptor activation provoked the cytosol-to-nucleus translocation of SMAD2 and SMAD3. SMAD2 knockdown by siRNA blocked MMP-2 induction and cell migration/invasion due to TGF-β1. TGF-β1 also provoked phosphorylation of MAPKs extracellular regulated kinase 1/2 and JNK1/2. Both MAPKs were upstream to p65/NF-kB inasmuch as both MAPKs' inhibitors PD98059 and SP600125 or their down-regulation by siRNA significantly blocked the TGF-β1-induced nuclear translocation of p65/NF-kB. In addition, p65/NF-κB siRNA knockdown inhibited the effects of TGF-β1 on both MMP-9 and cell migration/invasion. We conclude that TGF-β1 controls RSC96 Schwann cell migration and invasion through MMP-2 and MMP-9 activities. MMP-2 is controlled by SMAD2 whilst MMP-9 is controlled via an ERK1/2-JNK1/2-NF-κB dependent pathway.

Regulatory T Cells Induce Metastasis by Increasing Tgf-β and Enhancing the Epithelial–Mesenchymal Transition

Malignant melanoma is the most aggressive form of skin cancer; a substantial percentage of patients present with distant metastases. However, the mechanism of metastasis is not well understood. Here, we demonstrate that the administration of exogenous regulatory T cells (Tregs) into melanoma tumor-bearing mice results in a significant increase in lung metastasis. An increase in the invasive and metastatic phenotype of melanoma was mediated by cell-to-cell contact between melanoma cells and Tregs, which elevated the expression level of transforming growth factor-β (TGF-β) and the subsequent induction of the epithelial-to-mesenchymal transition (EMT).B16-BL6 melanoma tumors co-cultured with Tregs showed a larger population of migrating cells compared to B16-BL6 tumors cultured without Tregs. Additionally, the injection of exogenous Tregs into B16-BL6 melanoma tumors led to the recruitment and infiltration of endogenous Tregs into tumor tissues, thus increasing the overall Treg percentage in the tumor infiltrating lymphocyte population. Collectively, our findings propose novel mechanisms in which exogenous Treg-dependent upregulation of TGF-β and mesenchymal markers is important for augmenting the migration capacity and invasiveness of melanoma, thereby contributing to the metastasis.

Prognostic Significance of CD109 Expression in Patients with Ovarian Epithelial Cancer

Background

Ovarian epithelial cancer (OEC) is the second-most common gynecologic malignancy. CD109 expression is elevated in human tumor cell lines and carcinomas. A previous study showed that CD109 expression is elevated in human tumor cell lines and CD109 plays a role in cancer progression. Therefore, this study aimed to determine whether CD109 is expressed in OEC and can be useful in predicting the prognosis.

Methods

Immunohistochemical staining for CD109 and reverse transcription-quantitative polymerase chain reaction was performed. Then we compared CD109 expression and chemoresistance, overall survival, and recurrence-free survival of OEC patients. Chemoresistance was evaluated by dividing into good-response group and poor-response group by the time to recurrence after chemotherapy.

Results

CD109 expression was associated with overall survival (p = .020), but not recurrence-free survival (p = .290). CD109 expression was not an independent risk factor for overall survival due to its reliability (hazard ratio, 1.58; p = .160; 95% confidence interval, 0.82 to 3.05), although we found that CD109 positivity was related to chemoresistance. The poor-response group showed higher rates of CD109 expression than the good-response group (93.8% vs 66.7%, p = .047). Also, the CD109 mRNA expression level was 2.88 times higher in the poor-response group as compared to the good-response group (p = .001).

Conclusions

Examining the CD109 expression in patients with OEC may be helpful in predicting survival and chemotherapeutic effect.

Reduced USP33 expression in gastric cancer decreases inhibitory effects of Slit2-Robo1 signalling on cell migration and EMT

OBJECTIVES

Gastric cancer (GC) is one of the most common cancers in the world, causing a large number of deaths every year. The Slit-Robo signalling pathway, initially discovered for its critical role in neuronal guidance, has recently been shown to modulate tumour invasion and metastasis in several human cancers. However, the role of Slit-Robo signalling and the molecular mechanisms underlying its role in the pathogenesis of gastric cancer remains to be elucidated.

MATERIALS AND METHODS

Slit2, Robo1 and USP33 expressions were analysed in datasets obtained from the Oncomine database and measured in human gastric cancer specimens. The function of Slit2-Robo1-USP33 signalling on gastric cancer cells migration and epithelial-mesenchymal transition (EMT) was studied both in vitro and in vivo. The mechanism of the interaction between Robo1 and USP33 was explored by co-IP and ubiquitination protein analysis.

RESULTS

The mRNA and protein levels of Slit2 and Robo1 are lower in GC tissues relative to those in adjacent healthy tissues. Importantly, Slit2 inhibits GC cell migration and suppresses EMT process in a Robo-dependent manner. The inhibitory function of Slit2-Robo1 is mediated by ubiquitin-specific protease 33 (USP33) via deubiquitinating and stabilizing Robo1. USP33 expression is decreased in GC tissues, and reduced USP33 level is correlated with poor patient survival.

CONCLUSIONS

Our study reveals the inhibitory function of Slit-Robo signalling in GC and uncovers a role of USP33 in suppressing cancer cell migration and EMT by enhancing Slit2-Robo1 signalling. USP33 represents a feasible choice as a prognostic biomarker for GC.

Therapeutic potential of pharmacological TGF-β signaling pathway inhibitors in the pathogenesis of breast cancer

The TGF-β signaling pathway plays an important role in cancer cell proliferation, growth, inflammation, angiogenesis, and metastasis. The role of TGF-β signaling in the pathogenesis of breast cancer is complex. TGF-β acts as a tumor suppressor in the early stages of disease, and as a tumor promoter in its later stages. Over-activation of the TGF-β signaling pathway and over-expression of the TGF-β receptors are frequently found in breast tumors. Suppression of TGF-β pathway using biological or pharmacological inhibitors is a potentially novel therapeutic approach for breast cancer treatment. This review summarizes the regulatory role of TGF-β signaling in the pathogenesis of breast cancer for a better understanding and hence a better management of this disease.

Presence of S100A8/Gr1-Positive Myeloid-Derived Suppressor Cells in Primary Tumors and Visceral Organs Invaded by Breast Carcinoma Cells

BACKGROUND

Increased S100A8/A9 expression in Gr1-positive cells has been shown in myeloid-derived suppressor cells and may play a role in the formation of a metastatic milieu. We aimed to determine S100A8/A9 expression alone and with coexpression of Gr1 (a myeloid marker) in primary tumor and visceral tissues invaded by metastatic breast carcinoma.

MATERIALS AND METHODS

Female BALB/c mice were injected with 4TLM, 4THM, and 67NR orthotopically. Confluent cells (75%-80%) were used. Primary tumor, lung, liver, and spleen tissue samples were removed 26 days after injection. Peripheral blood smears and metastasis assay were performed, as was immunohistochemistry and staining.

RESULTS

S100A8/A9 immunoreactivity alone or coexpressed with Gr1 was found in primary tumors formed by 4TLM and 4THM cells, which was markedly higher than in primary tumors formed by nonmetastatic 67NR cells. Similarly, liver and lung tissues obtained from mice injected with 4TLM or 4THM cells were invaded by S100A8/A9-positive and Gr1-positive cells. Double-positive cells were markedly fewer in liver and lung tissues of animals injected with 67NR cells. S100A8/A9-positive cells were mostly localized in red pulp of spleens. We observed an increased number of neutrophils in the peripheral blood of mice injected with metastatic breast carcinoma cells.

CONCLUSION

Tumor-derived factors may increase S100A8/A9-positive cells locally and systemically, and S100A8/A9-positive cells may provide an appropriate milieu for the formation of metastasis.

Inhibiting YAP expression suppresses pancreatic cancer progression by disrupting tumor-stromal interactions

Background

Hippo/YAP pathway is known to be important for development, growth and organogenesis, and dysregulation of this pathway leads to tumor progression. We and others find that YAP is up-regulated in pancreatic ductal adenocarcinoma (PDAC) and associated with worse prognosis of patients. Activated pancreatic stellate cells (PSCs) forming the components of microenvironment that enhance pancreatic cancer cells (PCs) invasiveness and malignance. However, the role and mechanism of YAP in PDAC tumor-stromal interaction is largely unknown.

Methods

The expression of YAP in Pancreatic cancer cell lines and PDAC samples was examined by Western blot and IHC. The biological role of YAP on cancer cell proliferation, epithelial-mesenchymal transition (EMT) and invasion were evaluated by MTT, Quantitative real-time PCR analysis, Western blot analysis and invasion assay. The effect of YAP on PSC activation was evaluated by PC-PSC co-culture conditions and xenograft PDAC mouse model.

Results

Firstly, knockdown of YAP inhibits PDAC cell proliferation and invasion in vitro. In addition, YAP modulates the PC and PSC interaction via reducing the production of connective tissue growth factor (CTGF) from PCs, inhibits paracrine-mediated PSC activation under PC-PSC co-culture conditions and in turn disrupts TGF-β1-mediated tumor-stromal interactions. Lastly, inhibiting YAP expression prevents tumor growth and suppresses desmoplastic reaction in vivo.

Conclusions

These results demonstrate that YAP contributes to the proliferation and invasion of PC and the activation of PSC via tumor-stromal interactions and that targeting YAP may be a promising therapeutic strategy for PDAC treatment.

Electronic supplementary material

The online version of this article (10.1186/s13046-018-0740-4) contains supplementary material, which is available to authorized users.

Synthesis and Pharmacological Evaluation of Selective Histone Deacetylase 6 Inhibitors in Melanoma Models

Only a handful of therapies offer significant improvement in the overall survival in cases of melanoma, a cancer whose incidence has continued to rise in the past 30 years. In our effort to identify potent and isoform-selective histone deacetylase (HDAC) inhibitors as a therapeutic approach to melanoma, a series of new HDAC6 inhibitors based on the nexturastat A scaffold were prepared. The new analogues 4d, 4e, and 7b bearing added hydrophilic substituents, so as to establish additional hydrogen bonding on the rim of the HDAC6 catalytic pocket, exhibit improved potency against HDAC6 and retain selectivity over HDAC1. Compound 4d exhibits antiproliferative effects on several types of melanoma and lymphoma cells. Further studies indicates that 4d selectively increases acetylated tubulin levels in vitro and elicits an immune response through down-regulating cytokine IL-10. A preliminary in vivo efficacy study indicates that 4d possesses improved capability to inhibit melanoma tumor growth and that this effect is based on the regulation of inflammatory and immune responses.

Puerarin suppresses LPS-induced breast cancer cell migration, invasion and adhesion by blockage NF-κB and Erk pathway

BACKGROUND

Chronic inflammation is a major risk factor for the development and metastatic progression of breast cancer. Puerarin has long been used as traditional Chinese medicine, which possesses manifold physiological activities, including anti-inflammation and anti-cancer activities. However, its anti-cancer metastasis activity in breast cancer cell inflammation-mediated have not been studied.

METHODS

Cell viability was detected with Cell Counting Kit (CCK)-8. Transwell migration and invasion assay were performed to evaluate cell migration and invasion, respectively. Enzyme-linked immunosorbent assay (ELISA) was conducted to analysis the expression of inflammatory factor. In addition, mRNA and protein levels of related cytokines were determined by qRT- PCR assay and western blot analysis, respectively.

RESULTS

In this study, puerarin significantly inhibited lipopolysaccharide (LPS)-induced MCF-7 and MDA-MB-231 cell migration, invasion and adhesion. The mRNA and protein levels revealed that puerarin treatment effectively negated the expression of CCR7, CXCR4, MMP-2, MMP-9, ICAM and VCAM in LPS- activated MCF-7 and MDA-MB-231 cells. Further, the expression of inflammatory factor TNF-α and IL-6 in cell culture supernatant remarkably reduced. Finally, the result indicated that puerarin abrogated the NF-κB activation in breast cancer cells stimulated by LPS, which is mediated through inhibition of phosphorylation of p65 and IκBα. Also, puerarin inhibited phosphorylation of Erk in breast cancer cells LPS-induced.

CONCLUSIONS

This present study revealed that puerarin might be a novel therapeutic drug for breast cancer treatment.

Effects of TAZ on human dental pulp stem cell proliferation and migration

Transcriptional coactivator with PDZ‑binding motif (TAZ) acts as the key downstream regulatory target in the Hippo signaling pathway. TAZ overexpression has been reported to promote cellular proliferation and induce epithelial‑mesenchymal transition in human mammary epithelial cells. However, the effects of TAZ in the regulation of human dental pulp stem cell (hDPSC) proliferation and migration, as well as the molecular mechanisms underlying its actions, remain to be elucidated. The present study demonstrated that TAZ was expressed in hDPSCs. TAZ silencing, following hDPSC transfection with TAZ‑specific small interfering (si)RNA (siTAZ), inhibited cellular proliferation and migration in vitro. These effects appeared to be associated with the downregulation of connecting tissue growth factor (CTGF) and cysteine‑rich angiogenic inducer (Cyr) 61 expression. Further investigation of the mechanisms underlying the actions of TAZ in hDPSCs revealed that TAZ silencing suppressed CTGF and Cyr61 expression by interfering with transforming growth factor (TGF)‑β signaling pathways. The present results suggested that TAZ may be implicated in the proliferation and migration of hDPSCs, through the modulation of CTGF and Cyr61 expression via a TGF‑β‑dependent signaling pathway.

Immune microenvironment of gliomas

High-grade gliomas are rapidly progressing tumors of the central nervous system (CNS) with a very poor prognosis despite extensive resection combined with radiation and/or chemotherapy. Histopathological and flow cytometry analyses of human and rodent experimental gliomas revealed heterogeneity of a tumor and its niche, composed of reactive astrocytes, endothelial cells, and numerous immune cells. Infiltrating immune cells consist of CNS resident (microglia) and peripheral macrophages, granulocytes, myeloid-derived suppressor cells (MDSCs), and T lymphocytes. Intratumoral density of glioma-associated microglia/macrophages (GAMs) and MDSCs is the highest in malignant gliomas and inversely correlates with patient survival. Although GAMs have a few innate immune functions intact, their ability to be stimulated via TLRs, secrete cytokines, and upregulate co-stimulatory molecules is not sufficient to initiate antitumor immune responses. Moreover, tumor-reprogrammed GAMs release immunosuppressive cytokines and chemokines shaping antitumor responses. Both GAMs and MDSCs have ability to attract T regulatory lymphocytes to the tumor, but MDSCs inhibit cytotoxic responses mediated by natural killer cells, and block the activation of tumor-reactive CD4⁺ T helper cells and cytotoxic CD8⁺ T cells. The presence of regulatory T cells may further contribute to the lack of effective immune activation against malignant gliomas. We review the immunological aspects of glioma microenvironment, in particular composition and various roles of the immune cells infiltrating malignant human gliomas and experimental rodent gliomas. We describe tumor-derived signals and mechanisms driving myeloid cell accumulation and reprogramming. Although, understanding the complexity of cell-cell interactions in glioma microenvironment is far from being achieved, recent studies demonstrated several glioma-derived factors that trigger migration, accumulation, and reprogramming of immune cells. Identification of these factors may facilitate development of immunotherapy for gliomas as immunomodulatory and immune evasion mechanisms employed by malignant gliomas pose an appalling challenge to brain tumor immunotherapy.

Bone morphogenetic protein-2 and tumor growth: Diverse effects and possibilities for therapy

Concern regarding safety with respect to the clinical use of human bone morphogenetic protein-2 (BMP-2) has become an increasingly controversial topic. The role of BMP-2 in carcinogenesis is of particular concern. Although there have been many studies of this topic, the results have been contradictory and confusing. We conducted a systematic review of articles that are relevant to the relationship or effect of BMP-2 on all types of tumors and a total of 97 articles were included. Studies reported in these articles were classified into three major types: "expression studies", "in vitro studies", and "in vivo studies". An obvious pattern was that those works that hypothesize an inhibitory effect for BMP-2 most often examined only the proliferative properties of the tumor cells. This subset of studies also contained an extraordinary number of contradictory findings which made drawing a reliable general conclusion impossible. In general, we support a pro-tumorigenesis role for BMP-2 based on the data from these in vitro cell studies and in vivo animal studies, however, more clinical studies should be carried out to help make a firm conclusion.

Peripheral blood Th9 cells are a possible pharmacodynamic biomarker of nivolumab treatment efficacy in metastatic melanoma patients

Although nivolumab is associated with a significant improvement in overall survival and progression-free survival, only 20 to 40% of patients experience long-term benefit. It is therefore of great interest to identify a predictive marker of clinical benefit for nivolumab. To address this issue, the frequencies of CD4⁺ T cell subsets (Treg, Th1, Th2, Th9, Th17 and Th22), CD8⁺ T cells, and serum cytokine levels (IFNγ, IL-4, IL-9, IL-10, TGF-β) were assessed in 46 patients with melanoma. Eighteen patients responded to nivolumab, and the other 28 patients did not. An early increase in Th9 cell counts during the treatment with nivolumab was associated with an improved clinical response. Before the first nivolumab infusion, the responders displayed elevated serum concentrations of TGF-β compared to non-responders. Th9 induction by IL-4 and TGF-β was enhanced by PD-1/PD-L1 blockade in vitro. The role of IL-9 in disease progression was further assessed using a murine melanoma model. In vivo IL-9 blockade promoted melanoma progression in mice using an autochthonous mouse melanoma model, and the cytotoxic ability of murine melanoma-specific CD8⁺ T cells was enhanced in the presence of IL-9 in vitro. These findings suggest that Th9 cells, which produce IL-9, play an important role in the successful treatment of melanoma patients with nivolumab. Th9 cells therefore represent a valid biomarker to be further developed in the setting of anti-PD-1 therapy.

Ginsenoside Rd attenuates breast cancer metastasis implicating derepressing microRNA-18a-regulated Smad2 expression

Metastasis remains a major cause of mortality and poor prognosis in breast cancer patients. Anti-metastatic therapies are in great need to achieve optimal clinical outcome in breast cancer patients. Panax Notoginseng Saponins (PNS) has previously been shown to inhibit breast cancer metastasis in mouse. Here the potential anti-metastatic effect of one of the chemical compounds of PNS, ginsenoside Rd (Rd), was further evaluated in mouse mammary carcinoma 4T1 cells. The results revealed that Rd treatment dose-dependently suppressed cell migration and invasion in cultured 4T1 cells. In 4T1 cell-inoculated mice, Rd treatment led to decreased number of tumor lesions in lungs in both spontaneous and experimental metastasis models. Rd treatment resulted in increased expression of Smad2 in cultured 4T1 cells and in tumors grown from inoculated 4T1 cells. Rd treatment decreased the expression of microRNA (miR)-18a in cultured 4T1 cells and in tumors derived from inoculated 4T1 cells. Smad2 was further verified to be a direct target of miR-18a in 4T1 cells. The significant impact of Rd on counteracting miR-18a-medidated downregulation of Smad2 expression was also demonstrated. Together, the current work shows for the first time that Rd treatment attenuates breast cancer metastasis in part through derepressing miR-18a-mediated Smad2 expression regulation.

Stromal uptake and transmission of acid is a pathway for venting cancer cell-generated acid

Proliferation and invasion of cancer cells require favorable pH, yet potentially toxic quantities of acid are produced metabolically. Membrane-bound transporters extrude acid from cancer cells, but little is known about the mechanisms that handle acid once it is released into the poorly perfused extracellular space. Here, we studied acid handling by myofibroblasts (colon cancer-derived Hs675.T, intestinal InMyoFib, embryonic colon-derived CCD-112-CoN), skin fibroblasts (NHDF-Ad), and colorectal cancer (CRC) cells (HCT116, HT29) grown in monoculture or coculture. Expression of the acid-loading transporter anion exchanger 2 (AE2) (SLC4A2 product) was detected in myofibroblasts and fibroblasts, but not in CRC cells. Compared with CRC cells, Hs675.T and InMyoFib myofibroblasts had very high capacity to absorb extracellular acid. Acid uptake into CCD-112-CoN and NHDF-Ad cells was slower and comparable to levels in CRC cells, but increased alongside SLC4A2 expression under stimulation with transforming growth factor β1 (TGFβ1), a cytokine involved in cancer-stroma interplay. Myofibroblasts and fibroblasts are connected by gap junctions formed by proteins such as connexin-43, which allows the absorbed acid load to be transmitted across the stromal syncytium. To match the stimulatory effect on acid uptake, cell-to-cell coupling in NHDF-Ad and CCD-112-CoN cells was strengthened with TGFβ1. In contrast, acid transmission was absent between CRC cells, even after treatment with TGFβ1. Thus, stromal cells have the necessary molecular apparatus for assembling an acid-venting route that can improve the flow of metabolic acid through tumors. Importantly, the activities of stromal AE2 and connexin-43 do not place an energetic burden on cancer cells, allowing resources to be diverted for other activities.

Krüppel-like factor 4 is a novel prognostic predictor for urothelial carcinoma of bladder and it regulates TWIST1-mediated epithelial-mesenchymal transition

BACKGROUND

Krüppel-like factor 4 (KLF4) exerts tumor suppressive or oncogenic functions in a cell-type-dependent manner, but its prognostic role in urothelial carcinoma of bladder (UCB) remains unclear. We aimed to determine how KLF4 regulates epithelial-mesenchymal transition (EMT) and predicts patient survival in UCB.

PATIENTS AND METHODS

The roles of KLF4 and other EMT regulators in cancer progression were studied in UCB specimens of 398 patients, UCB cell lines. The results were validated by open-access The Cancer Genome Atlas dataset.

RESULTS

Over a median follow-up of 46.5 months, tissue microarray demonstrated that strong KLF4 expression was associated with higher risk toward metastasis and death (P<0.001). KLF4 expression positively correlated with TWIST1 and vimentin, and inversely correlated with E-cadherin expression. Metastasis-free survival was poorest in KLF4/TWIST1 coexpression group, followed by KLF4 or TWIST1 expression-alone group, and no-expression group (P<0.001). Multivariate analysis substantiated that KLF4/TWIST1 coexpression independently predicted overall mortality and metastasis risk with hazard ratios of 2.43 (95% CI: 1.65-3.64) and 7.54 (CI: 4.03-12.10). The Cancer Genome Atlas dataset of bladder cancer also revealed a trend toward decreased overall survival in the high KLF4 expression group as compared to the low KLF4 group. In vitro, KLF4 is accompanied with decreased E-cadherin and β-catenin expressions, increased vimentin and fibronectin expressions, and enhanced migration/invasion. KLF4 knockdown suppressed TWIST1 expression and inhibited EMT, migration and invasion, whereas enforced KLF4 overexpression activated TWIST1 expression and restored EMT and metastatic phenotype. Furthermore, TWIST1 knockdown abolished KLF4-faciliated EMT and metastatic feature without affecting KLF4 expression.

CONCLUSIONS

KLF4 promotes TWIST1-mediated EMT and may represent a novel prognostic predictor in UCB.

Effects of cisplatin on the LSD1-mediated invasion and metastasis of prostate cancer cells

Prostate cancer poses a major public health problem in men. Metastatic prostate cancer is incurable, and ultimately threatens the life of patients. Lysine-specific demethylase 1 (LSD1) is an androgen receptor-interacting protein that exerts a key role in regulating gene expression and is involved in numerous biological processes associated with prostate cancer. Cisplatin, also known as cis-diamminedichloroplatinum or DDP, is a standard chemotherapeutic agent used to treat prostate cancer; however, it has the disadvantage of various serious side effects. The present study aimed to investigate the effects of LSD1 knockdown, and the interplay between LSD1 and DDP, on prostate cancer cell proliferation, apoptosis and invasion, and, therefore, the potential of LSD1 as a target for prostate cancer therapy. Flow cytometric analysis, Cell Counting kit 8 assay, Transwell assay and western blotting results revealed that LSD1 knockdown, in combination with DDP treatment, exerted antiproliferative, proapoptotic and anti–invasive effects on PC3 prostate cancer cells. In addition, knockdown of LSD1 acted synergistically with DDP, thereby enhancing the induction of apoptosis, and the inhibition of proliferation and invasion in prostate cancer cells. These results indicated that LSD1 may serve as a potential therapeutic target, and may enhance the sensitivity of PC3 cells to DDP.

Conditional ablation of TGF-β signaling inhibits tumor progression and invasion in an induced mouse bladder cancer model

The role of transforming growth factor-β (TGF-β) signaling in cancer progression is still under debate. To determine the function of TGF-β signaling in bladder cancer progression, we conditionally knocked out the Tgfbr2 in mouse model after a N-butyl-N-4-hydroxybutyl Nitrosamine induced bladder carcinogenesis. We found the ablation of TGF-β signaling could inhibit the cancer cell proliferation, cancer stem cell population and EMT, hence suppressed the invasive cancer progression, which is similar with the result of TGF-β receptor I inhibitor treatment. These findings recognize the roles and mechanisms of TGF-β signaling in bladder cancer progression in vivo for the first time.

Urocortin attenuates TGFβ1-induced Snail1 and slug expressions: inhibitory role of Smad7 in Smad2/3 signaling in breast cancer cells

Corticortropin-releasing hormone (CRH) family are multifunctional endocrine-factors that regulate proliferation, apoptosis, and migration of various types of cancer cells. Deregulation of the transforming growth factor β1(TGFβ1) signal transduction promotes aggressive metastatic properties in late-stage breast cancers. We previously have demonstrated in breast cancer cell line that CRH suppressed TGFβ1-induced Epithelial-Mesenchymal Transition (EMT) via induction of E-cadherin. Our present data in MCF-7 and MDA-MB-231 cells showed that Urocortin (Ucn, a member of CRH family) inhibited TGFβ1 signaling by reducing Smad2/3 activation and subsequent nuclear translocation through increasing Smad7 expression, leading to downregulation of Snail1 and Slug, the two EMT promoters. We further found that Antalarmin (CRH receptor type 1, CRHR1 antagonist) and Antisauvagine-30 (CRH receptor type2, CRHR2 antagonist) abrogated the effects of Ucn on TGFβ1 signaling, implying that both active CRHR1 and CRHR2 participate in Ucn-repressed TGFβ1 signaling. Our findings, for the fist time, identify Ucn as a potential mediator that inhibits oncogenic signaling by TGFβ1 and suggest that activating CRHR1 and R2 may prove effective in diminishing breast cancer progression stimulated by TGFβ1.

An Integrated Genome-Wide Systems Genetics Screen for Breast Cancer Metastasis Susceptibility Genes

Metastasis remains the primary cause of patient morbidity and mortality in solid tumors and is due to the action of a large number of tumor-autonomous and non-autonomous factors. Here we report the results of a genome-wide integrated strategy to identify novel metastasis susceptibility candidate genes and molecular pathways in breast cancer metastasis. This analysis implicates a number of transcriptional regulators and suggests cell-mediated immunity is an important determinant. Moreover, the analysis identified novel or FDA-approved drugs as potentially useful for anti-metastatic therapy. Further explorations implementing this strategy may therefore provide a variety of information for clinical applications in the control and treatment of advanced neoplastic disease.

Metastasis, the spread and growth of tumor cells from the original tumor to secondary sites throughout the body, is the primary cause of cancer-related death for most solid tumor types. The process of metastasis is very complex, requiring multiple individual steps and the cooperation of different cell types during the dissemination and proliferation steps. Many genes are involved in this process, but at present few have been identified and characterized. In this study, we have integrated multiple genome-wide analysis methods to try to identify large numbers of candidate metastasis-associated genes and pathways based on a highly metastatic mouse model. Using this strategy, we have identified a number of genes that predict outcome of human breast cancer. These genes implicate specific molecular and cellular pathways in the metastatic process that might be used to intervene in the process. Furthermore, this integrated analysis implicates pre-existing drugs that might be re-purposed to help prevent or reduce metastatic burden in patients. The combined results obtained from this analytical strategy therefore provide an important platform for further genome-wide analysis into the etiology of metastatic disease.

mTOR inhibition by rapamycin increases ceramide synthesis by promoting transforming growth factor-β1/Smad signaling in the skin

Although mammalian target of rapamycin (mTOR) mediates a wide variety of biological functions, little information is available on the effect of mTOR on the functions of skin cells. In this study, we investigated effects of mTOR inhibition by rapamycin on ceramide synthesis in the skin of rats and human keratinocytes and its regulatory mechanisms. The phosphorylation of p70 S6 kinase, which indicates mTOR activation, was induced in the skin of rats fed a high-fat diet, but this abnormality was reversed by supplementation with rapamycin. Ceramide levels and the mRNA levels of serine palmitoyltransferase (SPT) and transforming growth factor (TGF)-β1 were suppressed in the skin of rats fed high-fat diets, but this abnormality was reversed by supplementation with rapamycin. TGF-β1-induced SPT mRNA expression was blocked by SB525334, an inhibitor of TGF-β1-induced Smad2/3 nuclear localization, in human keratinocytes. Rapamycin-induced SPT mRNA expression was blocked by an anti-TGF-β1 antibody or SB525334 in human keratinocytes. These results show that mTOR inhibition by rapamycin increases ceramide synthesis by promoting TGF-β1/Smad signaling in the skin.

Aberrant Splicing of Estrogen Receptor, HER2, and CD44 Genes in Breast Cancer

Breast cancer (BC) is the most common cause of cancer-related death among women under the age of 50 years. Established biomarkers, such as hormone receptors (estrogen receptor [ER]/progesterone receptor) and human epidermal growth factor receptor 2 (HER2), play significant roles in the selection of patients for endocrine and trastuzumab therapies. However, the initial treatment response is often followed by tumor relapse with intrinsic resistance to the first-line therapy, so it has been expected to identify novel molecular markers to improve the survival and quality of life of patients. Alternative splicing of pre-messenger RNAs is a ubiquitous and flexible mechanism for the control of gene expression in mammalian cells. It provides cells with the opportunity to create protein isoforms with different, even opposing, functions from a single genomic locus. Aberrant alternative splicing is very common in cancer where emerging tumor cells take advantage of this flexibility to produce proteins that promote cell growth and survival. While a number of splicing alterations have been reported in human cancers, we focus on aberrant splicing of ER, HER2, and CD44 genes from the viewpoint of BC development. ERα36, a splice variant from the ER1 locus, governs nongenomic membrane signaling pathways triggered by estrogen and confers 4-hydroxytamoxifen resistance in BC therapy. The alternative spliced isoform of HER2 lacking exon 20 (Δ16HER2) has been reported in human BC; this isoform is associated with transforming ability than the wild-type HER2 and recapitulates the phenotypes of endocrine therapy-resistant BC. Although both CD44 splice isoforms (CD44s, CD44v) play essential roles in BC development, CD44v is more associated with those with favorable prognosis, such as luminal A subtype, while CD44s is linked to those with poor prognosis, such as HER2 or basal cell subtypes that are often metastatic. Hence, the detection of splice variants from these loci will provide keys to understand the pathogenesis, predict the prognosis, and choose specific therapies for BC.

Phase 1 study of galunisertib, a TGF-beta receptor I kinase inhibitor, in Japanese patients with advanced solid tumors

PURPOSE

Inhibition of transforming growth factor-beta receptor I (TGF-beta RI)-mediated signaling pathways blocks tumor growth and metastases in nonclinical studies. Galunisertib (LY2157299), a small molecule inhibitor of TGF-beta RI serine/threonine kinase, had antitumor effects with acceptable safety/tolerability in a first-in-human dose (FHD) study conducted mainly in Caucasian patients with glioma. In this nonrandomized, open-label, dose-escalation study, we assessed safety/tolerability, pharmacokinetics (PK), and tumor response in Japanese patients.

METHODS

Patients with advanced and/or metastatic disease refractory were assigned sequentially to Cohort-1 (80 mg) or Cohort-2 (150 mg) of galunisertib, administered twice daily and treated using 2-week on, 2-week off treatment cycles. Dose escalation was guided by predefined PK criteria and dose-limiting toxicities (DLT). Safety assessments included treatment-emergent adverse events (TEAEs) and cardiac safety (ultrasound cardiography/Doppler imaging, electrocardiogram, chest computed tomography, and cardiotoxicity serum biomarkers).

RESULTS

Twelve patients (Cohort-1, n = 3; Cohort-2, n = 9) were enrolled and the most common types of cancer were pancreatic (n = 5) and lung cancer (n = 3). Seven patients (Cohort-1, n = 2; Cohort-2, n = 5) experienced possibly galunisertib-related TEAEs. The most frequent related TEAEs were brain natriuretic peptide increased (n = 2), leukopenia (n = 2), and rash (n = 2). No cardiovascular toxicities or other DLTs were reported. PK profile of galunisertib was consistent with the FHD study. Maximum plasma concentration was reached within 2 h post-dose, and the mean elimination half-life was 9 h.

CONCLUSIONS

Galunisertib had an acceptable tolerability and safety profile in Japanese patients with advanced cancers. CLINICATRIALS.GOV.

IDENTIFIER

NCT01722825.

The role of the transcription factor Ets1 in carcinoma

Ets1 belongs to the large family of the ETS domain family of transcription factors and is involved in cancer progression. In most carcinomas, Ets1 expression is linked to poor survival. In breast cancer, Ets1 is primarily expressed in the triple-negative subtype, which is associated with unfavorable prognosis. Ets1 contributes to the acquisition of cancer cell invasiveness, to EMT (epithelial-to-mesenchymal transition), to the development of drug resistance and neo-angiogenesis. The aim of this review is to summarize the current knowledge on the functions of Ets1 in carcinoma progression and on the mechanisms that regulate Ets1 activity in cancer.

Claudin 1 promotes migration and increases sensitivity to tamoxifen and anticancer drugs in luminal-like human breast cancer cells MCF7

Downregulation of claudin 1, a critical tight junction protein, has been correlated with increased invasiveness in breast cancer. However, recent studies suggest that claudin 1 contributes to the progression of some molecular subtypes of breast cancer. In this study, claudin 1 promotes migration in luminal-like MCF7 human breast cancer cells and increases their sensitivity to tamoxifen, etoposide, and cisplatin. We also observed an inverse relationship between upregulation of claudin 1 and TGFβ. Collectively, our results suggest that claudin 1 has the potential to be used as a predictive marker for treatment efficacy for specific breast cancer patient subgroups.

Modulation of Acid Sphingomyelinase in Melanoma Reprogrammes the Tumour Immune Microenvironment

The inflammatory microenvironment induces tumours to acquire an aggressive and immunosuppressive behaviour. Since acid sphingomyelinase (A-SMase) downregulation in melanoma was shown to determine a malignant phenotype, we aimed here to elucidate the role of A-SMase in the regulation of tumour immunogenic microenvironment using in vivo melanoma models in which A-SMase was either downregulated or maintained at constitutively high levels. We found high levels of inflammatory factors in low A-SMase expressing tumours, which also displayed an immunosuppressive/protumoural microenvironment: high levels of myeloid-derived suppressor cells (MDSCs) and regulatory T lymphocytes (Tregs), as well as low levels of dendritic cells (DCs). In contrast, the restoration of A-SMase in melanoma cells not only reduced tumour growth and immunosuppression, but also induced a high recruitment at tumour site of effector immune cells with an antitumoural function. Indeed, we observed a poor homing of MDSCs and Tregs and the increased recruitment of CD8⁺ and CD4⁺ T lymphocytes as well as the infiltration of DCs and CD8⁺/CD44^high T lymphocytes. This study demonstrates that change of A-SMase expression in cancer cells is sufficient per se to tune in vivo melanoma growth and that A-SMase levels modulate immune cells at tumour site. This may be taken into consideration in the setting of therapeutic strategies.