Connective tissue growth factor confers drug resistance in breast cancer through concomitant up-regulation of Bcl-xL and cIAP1

CCN1 is a therapeutic target upregulated in EML4-ALK mutant lung adenocarcinoma reversibly resistant to alectinib

There is limited understanding of the phenomenon of reversible drug resistance, which is characterized by tumor cells regaining sensitivity when the drug is changed or withdrawn after a period of drug resistance. This phenomenon is usually not associated with genetic alterations of tumor cells. In this study, reversible resistant state was induced by alectinib in EML4-ALK mutant lung cancer cell. By performing RNA sequencing on reversible drug-resistant cell line to examine changes in transcriptional profile, significant change in CCN1 was detected after withdrawal and repeated administration of alectinib. Targeting CCN1 resulted in inhibition of tumor cell proliferation and angiogenesis, and restoration of sensitivity to alectinib in reversible drug-resistant cells. Further studies revealed that CCN1 could affect the expression of VEGFA by affecting AKT phosphorylation, and the change of NF-κB could impact the activation of CCN1-AKT-VEGFA pathway. Suppressing NF-κB or CCN1 receptor could improve the sensitivity to alectinib, further suggesting that NF-κB and CCN1 might play a key role in overcoming reversible drug resistance.

CTGF (CCN2): a multifaceted mediator in breast cancer progression and therapeutic targeting

Breast cancer, with its diverse subtypes like ER-positive, HER-2-positive, and triple-negative, presents complex challenges demanding personalized treatment approaches. The intricate interplay of genetic, environmental, and lifestyle factors underscores its status as a primary contributor to cancer-related fatalities in women globally. Understanding the molecular drivers specific to each subtype is crucial for developing effective therapies. In this landscape, connective tissue growth factor (CTGF), also referred to as cellular communication network factor 2 (CCN2), emerges as a significant player. CTGF regulates critical biological activities like cell growth, invasion, and migration, impacting breast cancer development and progression. It modulates breast tumor microenvironment by promoting angiogenesis, activating cancer-associated fibroblasts (CAFs), and inducing inflammation. The activity of CTGF depends on several factors including oxygen levels, hormone signals, and growth factors and differs according to the type of breast cancer. CTGF can regulate breast cancer cells by activating various signaling pathways and modulating the transcription of other genes that are involved in tumor development and metastasis including S100A4, glucose transporter 3 (GLUT3), and vascular endothelial growth factor (VEGF). The matricellular protein can be considered a potential therapeutic target, as it can promote tumor growth and confer drug resistance in breast cancer. Numerous tactics, including neutralizing antibodies, antisense oligonucleotides, natural compounds, recombinant proteins, and short hairpin RNAs have been suggested to block its function. This review highlights the structure of CTGF, regulation of its expression, and current knowledge of its oncogenic role in breast cancer, as well as focusing on potential therapeutic strategies for targeting CTGF in breast cancer.

Advances towards potential cancer therapeutics targeting Hippo signaling

Decades of research into the Hippo signaling pathway have greatly advanced our understanding of its roles in organ growth, tissue regeneration, and tumorigenesis. The Hippo pathway is frequently dysregulated in human cancers and is recognized as a prominent cancer signaling pathway. Hence, the Hippo pathway represents an ideal molecular target for cancer therapies. This review will highlight recent advancements in targeting the Hippo pathway for cancer treatment and discuss the potential opportunities for developing new therapeutic modalities.

Multi-omics Analysis Revealed that the CCN Family Regulates Cell Crosstalk, Extracellular Matrix, and Immune Escape, Leading to a Poor Prognosis of Glioma

The CCN family is a group of matricellular proteins associated with the extracellular matrix. This study aims to explore the role of the CCN family in glioma development and its implications in the tumor microenvironment. Through analysis of bulk RNA-seq cohorts, correlations between CCN family expression and glioma subtypes, patient survival, and bioactive pathway enrichment were investigated. Additionally, single-cell datasets were employed to identify novel cell subgroups, followed by analyses of cell communication and transcription factors. Spatial transcriptomic analysis was utilized to validate the CCN family's involvement in glioma. Results indicate overexpression of CYR61,CTGF, and WISP1 in glioma, associated with unfavorable subtypes and reduced survival. Enrichment analyses revealed associations with oncogenic pathways, while CTGF and WISP1 expression correlated with increased infiltration of regulatory T cells and M2 macrophages. Single-cell analysis identified MES-like cells as the highest CCN expression. Moreover, intercellular signal transduction analysis demonstrated active pathways, including SPP1-CD44, in cell subgroups with elevated CYR61 and CTGF expression. Spatial transcriptomic analysis confirmed co-localization of CYR61,CTGF and SPP1-CD44 with high oncogenic pathway activity. These findings suggest that CCN family members may serve as potential prognostic biomarkers and therapeutic targets for glioma.

YAP at the Crossroads of Biomechanics and Drug Resistance in Human Cancer

Biomechanical forces are of fundamental importance in biology, diseases, and medicine. Mechanobiology is an emerging interdisciplinary field that studies how biological mechanisms are regulated by biomechanical forces and how physical principles can be leveraged to innovate new therapeutic strategies. This article reviews state-of-the-art mechanobiology knowledge about the yes-associated protein (YAP), a key mechanosensitive protein, and its roles in the development of drug resistance in human cancer. Specifically, the article discusses three topics: how YAP is mechanically regulated in living cells; the molecular mechanobiology mechanisms by which YAP, along with other functional pathways, influences drug resistance of cancer cells (particularly lung cancer cells); and finally, how the mechanical regulation of YAP can influence drug resistance and vice versa. By integrating these topics, we present a unified framework that has the potential to bring theoretical insights into the design of novel mechanomedicines and advance next-generation cancer therapies to suppress tumor progression and metastasis.

The role of YAP1 target gene CTGF in the anoikis resistance of rheumatoid arthritis synovial fibroblasts

OBJECTIVE

To analyse pro-survival mechanisms elicited in RA synovial fibroblasts (RASFs) upon detachment from their extracellular matrix dependent on the disintegrin metalloproteinase ADAM15 and Yes-associated protein kinase 1 (YAP1).

METHODS

Detachment-induced apoptosis was determined by caspase 3/7 assays. Immunofluorescent stainings, cell surface biotinylation and immunoblotting were applied to analyse phosphorylated kinases and subcellular localization of YAP1 and connective tissue growth factor (CTGF). Caspase and transwell transmigration assays served to study CTGF function.

RESULTS

Silencing of ADAM15 or YAP1 in RASFs leads to significantly increased levels of detachment-induced caspase activity. In non-silenced RASFs detachment causes simultaneous ADAM15-enhanced phosphorylation of YAP1 at S127, known for promoting its cytoplasmic localization, and Src-dependent phosphorylation at tyrosine Y357. The majority of nuclear YAP1 leaves the nucleus shortly after cell detachment, but prolonged detachment causes a marked nuclear re-entry of YAP1, resulting in significantly increased synthesis of CTGF. The newly synthesized CTGF, however, is not detectable in the supernatant, but is bound to the outside of the plasma membrane. In vitro studies demonstrated autocrine binding of CTGF to the EGF receptor and β1 integrin, with concomitant triggering of survival kinases, AKT1, ERK1/2, Src and focal adhesion kinase. Functional studies revealed anti-apoptotic effects of CTGF on detached RASFs and an enhancement of their potential for endothelial transmigration using HUVEC-coated transwells.

CONCLUSION

The elucidation of a new molecular mechanism that protects RASFs in the highly pro-apoptotic environment of inflamed RA joints by promoting anoikis-resistance and transendothelial migration via ADAM15/YAP1-mediated CTGF upregulation uncovers potentially new targets for future therapeutic intervention.

Functions of Yes-association protein (YAP) in cancer progression and anticancer therapy resistance

The Hippo pathway, a highly conserved kinase cascade, regulates cell proliferation, apoptosis, organ size, and tissue homeostasis. Dysregulation of this pathway reportedly plays an important role in the progression of various human cancers. Yes-association protein (YAP), the Hippo pathway’s core effector, is considered a marker for cancer therapy and patient prognosis. In addition, studies have indicated that YAP is involved in promoting anticancer drug resistance. This review summarizes current knowledge on YAP’s role in cancer progression, anticancer drug resistance, and advances in the development of YAP-targeting drugs. A thorough understanding of the complex interactions among molecular, cellular, and environmental factors concerning YAP function in cancer progression may provide new insight into the underlying mechanism of anticancer drug resistance. It might lead to improved prognosis through novel combined therapies.

Multifunctional regulatory protein connective tissue growth factor (CTGF): A potential therapeutic target for diverse diseases

Connective tissue growth factor (CTGF), a multifunctional protein of the CCN family, regulates cell proliferation, differentiation, adhesion, and a variety of other biological processes. It is involved in the disease-related pathways such as the Hippo pathway, p53 and nuclear factor kappa-B (NF-κB) pathways and thus contributes to the developments of inflammation, fibrosis, cancer and other diseases as a downstream effector. Therefore, CTGF might be a potential therapeutic target for treating various diseases. In recent years, the research on the potential of CTGF in the treatment of diseases has also been paid more attention. Several drugs targeting CTGF (monoclonal antibodies FG3149 and FG3019) are being assessed by clinical or preclinical trials and have shown promising outcomes. In this review, the cellular events regulated by CTGF, and the relationships between CTGF and pathogenesis of diseases are systematically summarized. In addition, we highlight the current researches, focusing on the preclinical and clinical trials concerned with CTGF as the therapeutic target.

DNA Origami Frameworks Enabled Self-Protective siRNA Delivery for Dual Enhancement of Chemo-Photothermal Combination Therapy

Although chemotherapy and photothermal therapy are widely used to combat cancer, their efficacy is often limited by multidrug resistance. Small interfering RNAs (siRNAs) have ability to suppress the expression of target genes, which has been extensively employed for combating the multidrug resistance to chemodrugs and hyperthermia in cancer therapy. However, efficient delivery of siRNAs along with chemo-photothermal agents in vivo is still an enormous challenge. Herein, octahedral DNA origami frameworks (OctDOFs) are constructed as a nanovehicle for precise organization and orchestrated delivery of siRNAs, chemodrugs (doxorubicin, Dox), and photothermal agents (gold nanorods, AuNRs) in combinatorial treatment of cancer. The inner cavity of the rigid OctDOFs structure is able to shield the encapsulated siRNAs during transportation by sterically hindering RNase degradation and protein binding, thus achieving effective downregulation of connective tissue growth factor (CTGF) and heat shock protein 72 (HSP72) for dual sensitization of cancer cells to chemodrugs and hyperthermia. By amplifying chemo-photothermal therapeutic potency with siRNAs, the proposed OctDOFs exhibited superior cytotoxicity and tumor inhibition efficacy in vitro and in vivo. This nanovehicle creates a promising siRNA delivery platform for precise medication and combination therapy.

Atractylenolide-I Sensitizes Triple-Negative Breast Cancer Cells to Paclitaxel by Blocking CTGF Expression and Fibroblast Activation

This investigation was conducted to elucidate whether atractylenolide-I (ATL-1), which is the main component of Atractylodes macrocephala Koidz, can sensitize triple-negative breast cancer (TNBC) cells to paclitaxel and investigate the possible mechanism involved. We discovered that ATL-1 could inhibit tumor cell migration and increase the sensitivity of tumor cells to paclitaxel. ATL-1 downregulated the expression and secretion of CTGF in TNBC cells. Apart from inhibiting TNBC cell migration via CTGF, ATL-1 downregulated the expression of CTGF in fibroblasts and decreased the ability of breast cancer cells to transform fibroblasts into cancer-associated fibroblasts (CAFs), which in turn increased the sensitivity of TNBC cells to paclitaxel. In a mouse model, we found that ATL-1 treatments could enhance the chemotherapeutic effect of paclitaxel on tumors and reduce tumor metastasis to the lungs and liver. Primary cultured fibroblasts derived from inoculated tumors in mice treated with ATL-1 combined with paclitaxel expressed relatively low levels of CAF markers. Collectively, our data indicate that ATL-1 can sensitize TNBC cells to paclitaxel by blocking CTGF expression and fibroblast activation and could be helpful in future research to determine the value of ATL-1 in the clinical setting.

FOXD1 promotes dedifferentiation and targeted therapy resistance in melanoma by regulating the expression of connective tissue growth factor

Metastatic melanoma is an aggressive skin cancer and associated with a poor prognosis. In clinical terms, targeted therapy is one of the most important treatments for patients with BRAF^V600E -mutated advanced melanoma. However, the development of resistance to this treatment compromises its therapeutic success. We previously demonstrated that forkhead box D1 (FOXD1) regulates melanoma migration and invasion. Here, we found that FOXD1 was highly expressed in melanoma cells and was associated with a poor survival of patients with metastatic melanoma. Upregulation of FOXD1 expression enhanced melanoma cells' resistance to vemurafenib (BRAF inhibitor [BRAFi]) or vemurafenib and cobimetinib (MEK inhibitor) combination treatment whereas loss of FOXD1 increased the sensitivity to treatment. By comparing gene expression levels between FOXD1 knockdown (KD) and overexpressing (OE) cells, we identified the connective tissue growth factor (CTGF) as a downstream factor of FOXD1. Chromatin immunoprecipitation and luciferase assay demonstrated the direct binding of FOXD1 to the CTGF promoter. Similar to FOXD1, knockdown of CTGF increased the sensitivity of BRAFi-resistant cells to vemurafenib. FOXD1 KD cells treated with recombinant CTGF protein were less sensitive towards vemurafenib compared to untreated FOXD1 KD cells. Based on these findings, we conclude that FOXD1 might be a promising new diagnostic marker and a therapeutic target for the treatment of targeted therapy resistant melanoma.

CTGF regulates cell proliferation, migration, and glucose metabolism through activation of FAK signaling in triple-negative breast cancer

Connective tissue growth factor (CTGF), also known as CCN2, is a member of the CCN protein family of secreted proteins with roles in diverse biological processes. CTGF regulates biological functions such as cell proliferation, migration, adhesion, wound healing, and angiogenesis. In this study, we demonstrate a mechanistic link between CTGF and enhanced aerobic glycolysis in triple-negative breast cancer (TNBC). We found that CTGF is overexpressed in TNBC and high CTGF expression is correlated with a poor prognosis. Also, CTGF was required for in vivo tumorigenesis and in vitro proliferation, migration, invasion, and adhesion of TNBC cells. Our results indicate that extracellular CTGF binds directly to integrin αvβ3, activating the FAK/Src/NF-κB p65 signaling axis, which results in transcriptional upregulation of Glut3. Neutralization of CTGF decreased cell proliferation, migration, and invasion through downregulation of Glut3-mediated glycolytic phenotypes. Overall, our work suggests a novel function for CTGF as a modulator of cancer metabolism, indicating that CTGF is a potential therapeutic target in TNBC.

The Hippo Signaling Pathway in Drug Resistance in Cancer

Simple Summary

Although great breakthroughs have been made in cancer treatment following the development of targeted therapy and immune therapy, resistance against anti-cancer drugs remains one of the most challenging conundrums. Considerable effort has been made to discover the underlying mechanisms through which malignant tumor cells acquire or develop resistance to anti-cancer treatment. The Hippo signaling pathway appears to play an important role in this process. This review focuses on how components in the human Hippo signaling pathway contribute to drug resistance in a variety of cancer types. This article also summarizes current pharmacological interventions that are able to target the Hippo signaling pathway and serve as potential anti-cancer therapeutics.

Abstract

Chemotherapy represents one of the most efficacious strategies to treat cancer patients, bringing advantageous changes at least temporarily even to those patients with incurable malignancies. However, most patients respond poorly after a certain number of cycles of treatment due to the development of drug resistance. Resistance to drugs administrated to cancer patients greatly limits the benefits that patients can achieve and continues to be a severe clinical difficulty. Among the mechanisms which have been uncovered to mediate anti-cancer drug resistance, the Hippo signaling pathway is gaining increasing attention due to the remarkable oncogenic activities of its components (for example, YAP and TAZ) and their druggable properties. This review will highlight current understanding of how the Hippo signaling pathway regulates anti-cancer drug resistance in tumor cells, and currently available pharmacological interventions targeting the Hippo pathway to eradicate malignant cells and potentially treat cancer patients.

Targeting CTGF in Cancer: An Emerging Therapeutic Opportunity

Despite the dramatic advances in cancer research over the decades, effective therapeutic strategies are still urgently needed. Increasing evidence indicates that connective tissue growth factor (CTGF), a multifunctional signaling modulator, promotes cancer initiation, progression, and metastasis by regulating cell proliferation, migration, invasion, drug resistance, and epithelial-mesenchymal transition (EMT). CTGF is also involved in the tumor microenvironment in most of the nodes, including angiogenesis, inflammation, and cancer-associated fibroblast (CAF) activation. In this review, we comprehensively discuss the expression of CTGF and its regulation, oncogenic role, clinical relevance, targeting strategies, and therapeutic agents. Herein, we propose that CTGF is a promising cancer therapeutic target that could potentially improve the clinical outcomes of cancer patients.

Endosomes, lysosomes, and the role of endosomal and lysosomal biogenesis in cancer development

Endosomes and lysosomes are membrane-bound organelles crucial for the normal functioning of the eukaryotic cell. The primary function of endosomes relates to the transportation of extracellular material into the intracellular domain. Lysosomes, on the other hand, are primarily involved in the degradation of macromolecules. Endosomes and lysosomes interact through two distinct pathways: kiss-and-run and direct fusion. In addition to the internalization of particles, endosomes also play an important role in cell signaling and autophagy. Disruptions in either of these processes may contribute to cancer development. Lysosomal proteins, such as cathepsins, can play a role in both tumorigenesis and cancer cell apoptosis. Since endosomal and lysosomal biogenesis and signaling are important components of normal cellular growth and proliferation, proteins involved in these processes are attractive targets for cancer research and, potentially, therapeutics. This literature review provides an overview of the endocytic pathway, endolysosome formation, and the interplay between endosomal/lysosomal biogenesis and carcinogenesis.

MicroRNA-584 Impairs Cellular Proliferation and Sensitizes Osteosarcoma Cells to Cisplatin and Taxanes by Targeting CCN2

Background

Osteosarcoma (OS), an aggressive malignant neoplasm, exhibits osteoblastic differentiation. Cisplatin (DDP) and taxanes are among the most effective drugs for OS patients. Nevertheless, the drug resistance remains a main limitation to efficacious chemotherapy in OS. The current report sets to explore the biological function of microRNA-584 (miR-584) and the potential mechanism underlying OS cells resistance to these two drugs.

Materials and Methods

The expression profiles of miR-584 and connective tissue growth factor (CTGF, CCN2) in OS tissue samples and cell lines were tested by means of reverse transcription-quantitative polymerase chain reaction and Western blot. U2OS and MG63 cell lines were delivered with miR-584 mimic alone or plus CCN2 to excavate theirs functions by cell counting kit-8 and EdU, flow cytometric analysis, as well as transwell assay, severally. Western bot analysis was conducted to examine the expression of IκBα, pIκBα, NF-κB and pNF-κB. Dual-luciferase reporter gene assay was carried out to assess the targets of miR-584.

Results

The downregulation of miR-584 was identified in OS tissues and cells, which was closely linked to the dismal prognosis of OS patients. Overexpression of miR-584 repressed cell viability, migration as well as invasion, potentiated apoptosis and sensitized OS cells to DDP and taxanes. Mechanism investigation specified a direct targeting relationship between CCN2 and miR-584 in OS.

Conclusion

In conclusion, miR-584 has the potency to act as a therapeutic maneuver for OS mainly by inducing the chemosensitivity of OS cells to DDP and taxanes.

Connective tissue growth factor as an unfavorable prognostic marker promotes the proliferation, migration, and invasion of gliomas

BACKGROUND

In consideration of the difficulty in diagnosing high heterogeneous glioma, valuable prognostic markers are urgent to be investigated. This study aimed to verify that connective tissue growth factor (CTGF) is associated with the clinical prognosis of glioma, also to analyze the effect of CTGF on the biological function.

METHODS

In this study, glioma and non-tumor tissue samples were obtained in 2012 to 2014 from the Department of Neurosurgery of Nanfang Hospital of Southern Medical University, Guangzhou, China. Based on messenger RNA (mRNA) data from the Cancer Genome Atlas (TCGA) and CCGA dataset, combined with related clinical information, we detected the expression of CTGF mRNA in glioma and assessed its effect on the prognosis of glioma patients. High expression of CTGF mRNA and protein in glioma were verified by reverse transcription-polymerase chain reaction, immunohistochemistry, and Western blotting. The role of CTGF in the proliferation, migration, and invasion of gliomas were respectively identified by methylthiazoletetrazolium assay, Transwell and Boyden assay in vitro. The effect on glioma cell circle was assessed by flow cytometry. For higher expression of CTGF in glioblastoma (GBM), the biological function of CTGF in GBM was investigated by gene ontology (GO) analysis.

RESULTS

In depth analysis of TCGA data revealed that CTGF mRNA was highly expressed in glioma (GBM, n = 163; lowly proliferative glioma [LGG], n = 518; non-tumor brain tissue, n = 207; LGG, t = 2.410, GBM, t = 2.364, P < 0.05). CTGF mRNA and protein expression in glioma (86%) was significantly higher than that in non-tumor tissues (18%) verified by collected samples. Glioma patients with higher expression of CTGF showed an obviously poorer overall survival (35.4 and 27.0 months compared to 63.3 and 55.1 months in TCGA and Chinese Glioma Genome Atlas (CGGA) databases separately, CGGA: χ = 7.596, P = 0.0059; TCGA: χ = 10.46, P = 0.0012). Inhibiting CTGF expression could significantly suppress the proliferation, migration, and invasion of gliomas. CTGF higher expression had been observed in GBM, and GO analysis demonstrated that the function of CTGF in GBM was mainly associated with metabolism and energy pathways (P < 0.001).

CONCLUSIONS

CTGF is highly expressed in glioma, especially GBM, as an unfavorable and independent prognostic marker for glioma patients and facilitates the progress of glioma.

The Matrix Revolution: Matricellular Proteins and Restructuring of the Cancer Microenvironment

The extracellular matrix (ECM) surrounding cells is indispensable for regulating their behavior. The dynamics of ECM signaling are tightly controlled throughout growth and development. During tissue remodeling, matricellular proteins (MCP) are secreted into the ECM. These factors do not serve classical structural roles, but rather regulate matrix proteins and cell-matrix interactions to influence normal cellular functions. In the tumor microenvironment, it is becoming increasingly clear that aberrantly expressed MCPs can support multiple hallmarks of carcinogenesis by interacting with various cellular components that are coupled to an array of downstream signals. Moreover, MCPs also reorganize the biomechanical properties of the ECM to accommodate metastasis and tumor colonization. This realization is stimulating new research on MCPs as reliable and accessible biomarkers in cancer, as well as effective and selective therapeutic targets.

Overexpression of connective tissue growth factor is associated with tumor progression and unfavorable prognosis in endometrial cancer

OBJECTIVES

This study was to explore the prognostic value of connective tissue growth factor (CTGF) expression in endometrial cancer (EC).

METHODS

We compared CTGF expression in 198 samples from patients with endometrial cancer and 50 samples from patients with healthy endometrial tissues as determined by immunohistochemistry.

RESULTS

Expression of CTGF was significantly higher in endometrial cancers as compared to normal endometrial tissues. Positive CTGF expression displayed a strong association with CA125 level, histological grade, depth of myometrial invasion and the International Federation of Gynecology and Obstetrics (FIGO) stage. Our findings revealed histological grade, depth of myometrial invasion, FIGO stage, vascular/lymphatic invasion, and the CTGF expression are related to 5-year survival in patients with endometrial cancer. Positive CTGF expression, lymph node status, as well as vascular/lymphatic invasion, were identified as independent prognostic factors in endometrial cancer.

CONCLUTIONS

Over-expression of CTGF is an independent prognostic factor that will allow the successful differentiation of high-risk population from the group of patients with stage III-IV endometrial cancer. The up-regulation of CTGF may contribute to the progression of endometrial cancer and serve as a new prognostic biomarker in patients with endometrial cancer survival.

Expression of connective tissue growth factor as a prognostic indicator and its possible involvement in the aggressive properties of epithelial ovarian carcinoma

Recently, connective tissue growth factor (CTGF) was demonstrated to be associated with aggressive characteristics, including proliferation, invasion and metastasis, in a number of malignancies. Here, we investigated the expression and function of CTGF in epithelial ovarian carcinoma (EOC) to clarify its molecular mechanism and clinical significance. Paraffin sections from clinical samples of EOC (N=104) were immunostained with the CTGF antibody, and then the staining positivity was semiquantitatively examined. Moreover, we explored the role of CTGF expression in the migration-promoting effect on and chemoresistance of EOC cells. The results revealed that of the 104 EOC patients, the low and high CTGF staining expression rates were 65 (62.5%) and 39 (37.5%), respectively. Patients belonging to the higher-level CTGF group showed poorer progression-free (PFS) and overall survival (OS) rates than those in the lower-level group [PFS (log-rank: P=0.0076) and OS (log-rank: P=0.0078), respectively]. Multivariable analysis showed that CTGF expression was a significant predictor of poorer PFS and OS [PFS: HR (high vs. low): 1.837, 95% CI: 1.023–3.289 (P=0.0418); OS: HR: 2.141, 95% CI: 1.077–4.296 (P=0.0300)]. In in vitro studies, in acquired paclitaxel (PTX)-resistant EOC cells, the silencing of CTGF expression led to the restoration of PTX sensitivity. Furthermore, we confirmed that the TGF-β-dependent migration-promoting effect on these CTGF-depleted cells was completely inhibited. In conclusion, the results of the present study suggest the possible involvement of CTGF in the migration-promoting effect and chemoresistance of EOC, suggesting that it may be a target for overcoming the malignant properties of EOC.

Estrogen administration reduces the risk of pulmonary arterial hypertension by modulating the miR-133a signaling pathways in rats

We aimed to investigate how estrogen (ES) is implicated in the pathogenesis of pulmonary arterial hypertension (PAH) potentially by reducing the extent of vascular remodeling in females. HE assay, Western Blot, IHC, and real-time PCR were carried out to observe the role of ES in regulating miR-133a expression and the levels of MYOSLID, SRF, CTGF, and vascular remodeling in rats. In addition, MTT assay and flow cytometry were utilized to observe how ES affects cell proliferation and cell cycle in PAH. Moreover, luciferase assays were carried out to clarity the regulatory relationship between miR-133a and its downstream targets. ES administration relieved the deregulation of miR-133a, MYOSLID, SRF, and CTGF in PAH rats. In addition, ES also reduced the thickening of blood vessels in PAH rats. ES could activate miR-133a promoter and arrest the cells in the G0/G1 cycle, thus dose-dependently suppressing the proliferation of cells. In addition, the presence of ES, MYOSLID siRNA, or miR-133a precursor all altered the expression of MYOSLID, SP1, SRF, and CTGF, thus establishing a molecular signaling pathway among these factors. Furthermore, miR-133a could bind to SP1, MYOSLID, SRF, and CTGF to reduce their expression. Moreover, SRF was proved to function as an activator of miR-133a promoter. Two feedback loops were established in this study: a negative feedback loop between SRF and miR-133a, and a positive loop among miR-133a/SRF/MLK1/MYOSLID. ES treatment upregulates miR-133a expression and reduces the incidence of PAH and vascular remodeling.

Cytotoxic Effect of Paclitaxel and Lapatinib Co-Delivered in Polylactide-co-Poly(ethylene glycol) Micelles on HER-2-Negative Breast Cancer Cells

To find better strategies to enhance the cytotoxic effect of paclitaxel (PTX) and lapatinib (LAP) against breast cancer cells, we analyzed the efficacy of a novel delivery system containing polylactide-co-poly(ethylene glycol) (PLA-PEG) filomicelles of over 100 nm in length and spherical micelles of approximately 20 nm in diameter. The ¹H NMR measurements confirmed the incorporation of PTX and LAP into micelles. Analysis of the drug release mechanism revealed the diffusion-controlled release of LAP and anomalous transport of PTX. Drug content analysis in lyophilized micelles and micellar solution showed their good storage stability for at least 6 weeks. Blank micelles, LAP-loaded micelles and free LAP did not affect MCF-7 breast cancer cell proliferation, suggesting that the cytotoxicity of PTX-, PTX/LAP-loaded micelles, and the binary mixture of free PTX and LAP was solely caused by PTX. PTX/LAP-loaded micelles showed greater toxicity compared to the binary mixture of PTX and LAP after 48 h and 72 h. Only free PTX alone induced P-gp activity. This study showed the feasibility of using a LAP and PTX combination to overcome MDR in MCF-7 cells, particularly when co-loaded into micelles. We suggest that PTX/LAP micelles can be applicable not only for the therapy of HER-2-positive, but also HER-2-negative breast cancers.

YAP/TAZ Signaling and Resistance to Cancer Therapy

Drug resistance is a major challenge in cancer treatment. Emerging evidence indicates that deregulation of YAP/TAZ signaling may be a major mechanism of intrinsic and acquired resistance to various targeted and chemotherapies. Moreover, YAP/TAZ-mediated expression of PD-L1 and multiple cytokines is pivotal for tumor immune evasion. While direct inhibitors of YAP/TAZ are still under development, FDA-approved drugs that indirectly block YAP/TAZ activation or critical downstream targets of YAP/TAZ have shown promise in the clinic in reducing therapy resistance. Finally, BET inhibitors, which reportedly block YAP/TAZ-mediated transcription, present another potential venue to overcome YAP/TAZ-induced drug resistance.

Angiotensin-converting enzyme 2 activation suppresses pulmonary vascular remodeling by inducing apoptosis through the Hippo signaling pathway in rats with pulmonary arterial hypertension

Objective: To investigate the effects of angiotensin-converting enzyme 2 (ACE2) activation on pulmonary arterial cell apoptosis during pulmonary vascular remodeling associated with pulmonary arterial hypertension (PAH) and to elucidate potential mechanisms related to Hippo signaling. Methods: PAH model was developed by injecting monocrotaline combined with left pneumonectomy using Sprague-Dawley rat. Then, resorcinolnaphthalein (Res; ACE2 activator), MLN-4760 (ACE2 inhibitor), A-779 (Mas inhibitor), and 4-((5,10-dimethyl-6-oxo-6,10-dihydro-5H-pyrimido[5,4-b]thieno[3,2-e][1,4]diazepin-2-yl)amino) benzenesulfonamide (XMU-MP-1; MST1/2 inhibitor) were administered via continuous subcutaneous or intraperitoneal injection for 3 weeks. Animals were randomly divided into six groups: control, PAH, PAH+Res, PAH+Res+MLN-4760, PAH+Res+A-779, and PAH+Res+XMU-MP-1. On 21 day, hemodynamics and pathologic lesions were evaluated. Apoptosis and apoptosis-associated proteins were detected by TUNEL and western blotting. ACE2 activity and Hippo pathway components including large tumor suppressor 1 (LATS1), Yes-associated protein (Yap), and phosphorylated Yap (p-Yap) were investigated by fluorogenic peptide assays and western blotting. Results: In the PAH models, the mean pulmonary arterial pressure, right ventricular hypertrophy index, pulmonary vascular remodeling, anti-apoptotic protein Bcl-2 and Yap were all increased but the pulmonary arterial cell apoptosis, pro-apoptotic proteins caspase-3 and Bax were lower. ACE2 activation significantly ameliorated pulmonary arterial remodeling, this action was related to increased apoptosis and up-regulation of LATS1 and p-Yap. These protective effects were mitigated by the co-administration of A779 or MLN-4760. Moreover, inhibiting the Hippo/LATS1/Yap pathway with XMU-MP-1 blocked apoptosis in pulmonary vascular cells induced by ACE2 activation during the prevention of PAH. Conclusions: Our findings suggest that ACE2 activation attenuates pulmonary vascular remodeling by inducing pulmonary arterial cell apoptosis via Hippo/Yap signaling during the development of PAH.

Connective tissue growth factor-specific monoclonal antibody inhibits growth of malignant mesothelioma in an orthotopic mouse model

Malignant mesothelioma is an aggressive neoplasm with no particularly effective treatments. We previously reported that overexpression of connective tissue growth factor (CTGF/CCN2) promotes mesothelioma growth, thus suggesting it as a novel molecular target. A human monoclonal antibody that antagonizes CTGF (FG-3019, pamrevlumab) attenuates malignant properties of different kinds of human cancers and is currently under clinical trial for the treatment of pancreatic cancer. This study reports the effects of FG-3019 on human mesothelioma in vitro and in vivo. We analyzed the effects of FG-3019 on the proliferation, apoptosis, migration/invasion, adhesion and anchorage-independent growth in three human mesothelioma cell lines, among which ACC-MESO-4 was most efficiently blocked with FG-3019 and was chosen for in vivo experiments. We also evaluated the coexistent effects of fibroblasts on mesothelioma in vitro, which are also known to produce CTGF in various pathologic situations. Coexistent fibroblasts in transwell systems remarkably promoted the proliferation and migration/invasion of mesothelioma cells. In orthotopic nude mice model, FG-3019 significantly inhibited mesothelioma growth. Histological analyses revealed that FG-3019 not only inhibited the proliferation but also induced apoptosis in both mesothelioma cells and fibroblasts. Our data suggest that FG-3019 antibody therapy could be a novel additional choice for the treatment of mesothelioma.

"Stealth and Fully-Laden" Drug Carriers: Self-Assembled Nanogels Encapsulated with Epigallocatechin Gallate and siRNA for Drug-Resistant Breast Cancer Therapy

For codelivery of therapeutic genes and chemical agents in combined therapy, the ideal drug delivery system entails high-capacity and low-body toxicity carriers, allowing adequate drug dose for tumor regions while yielding low residues in normal tissues. To augment the gene/drug load capacity and circumvent the potential toxicity brought by traditional inorganic and polymeric nanocarriers, a "stealth" carrier was herein designed in a simple self-assembly of (-)-epigallocatechin-3- O-gallate (EGCG) and small interfering RNA (siRNA) by recruiting protamine as a biodegradable medium for the treatment of drug-resistant triple-negative breast cancer. In the self-assembled nanogel, entrapped siRNA played a central role in sensitizing the tumor response to EGCG-involved chemotherapy, and the positively charged protamine served as the assembly skeleton to fully accommodate gene and drug molecules and minimize the factors causing side effects. As compared to stand-alone chemotherapy with EGCG, the multicomponent nanogel revealed a 15-fold increase in the cytotoxicity to drug-resistant MDA-MB-231 cell line. Moreover, equipped with hyaluronic acid and tumor-homing cell-penetrating peptide as the outmost targeting ligands, the siRNA- and EGCG-loaded nanogel demonstrates superior selectivity and tumor growth inhibition to free EGCG in xenograft MDA-MB-231 tumor-bearing mice. Meanwhile, thanks to the acknowledged biosafety of protamine, little toxicity was found to normal tissues and organs in the animal model. This gene/drug self-assembly caged in a biodegradable carrier opens up an effective and secure route for drug-resistant cancer therapy and provides a versatile approach for codelivery of other genes and drugs for different medical purposes.

The Role of Hippo Pathway in Cancer Stem Cell Biology

The biological significance and deregulation of the Hippo pathway during organ growth and tumorigenesis have received a surge of interest in the past decade. The Hippo pathway core kinases, MST1/2 and LATS1/2, are tumor suppressors that inhibit the oncogenic nuclear function of YAP/TAZ and TEAD. In addition to earlier studies that highlight the role of Hippo pathway in organ size control, cell proliferation, and tumor development, recent evidence demonstrates its critical role in cancer stem cell biology, including EMT, drug resistance, and self-renewal. Here we provide a brief overview of the regulatory mechanisms of the Hippo pathway, its role in cancer stem cell biology, and promising therapeutic interventions.

PCPA protects against monocrotaline-induced pulmonary arterial remodeling in rats: potential roles of connective tissue growth factor

The purpose of this study was to investigate the mechanism of monocrotaline (MCT)-induced pulmonary artery hypertension (PAH) and determine whether 4-chloro-DL-phenylalanine (PCPA) could inhibit pulmonary arterial remodeling associated with connective tissue growth factor (CTGF) expression and downstream signal pathway. MCT was administered to forty Sprague Dawley rats to establish the PAH model. PCPA was administered at doses of 50 and 100 mg/kg once daily for 3 weeks via intraperitoneal injection. On day 22, the pulmonary arterial pressure (PAP), right ventricle hypertrophy index (RVI) and pulmonary artery morphology were assessed and the serotonin receptor-1B (SR-1B), CTGF, p-ERK/ERK were measured by western blot or immunohistochemistry. The concentration of serotonin in plasma was checked by ELISA. Apoptosis and apoptosis-related indexes were detected by TUNEL and western blot. In the MCT-induced PAH models, the PAP, RVI, pulmonary vascular remodeling, SR-1B index, CTGF index, anti-apoptotic factors bcl-xl and bcl-2, serotonin concentration in plasma were all increased and the pro-apoptotic factor caspase-3 was reduced. PCPA significantly ameliorated pulmonary arterial remodeling induced by MCT, and this action was associated with accelerated apoptosis and down-regulation of CTGF, SR-1B and p-ERK/ERK. The present study suggests that PCPA protects against the pathogenesis of PAH by suppressing remodeling and inducing apoptosis, which are likely associated with CTGF and downstream ERK signaling pathway in rats.

Glucose impairs tamoxifen responsiveness modulating connective tissue growth factor in breast cancer cells

Type 2 diabetes and obesity are negative prognostic factors in patients with breast cancer (BC). We found that sensitivity to tamoxifen was reduced by 2-fold by 25 mM glucose (High Glucose; HG) compared to 5.5 mM glucose (Low Glucose; LG) in MCF7 BC cells. Shifting from HG to LG ameliorated MCF7 cell responsiveness to tamoxifen. RNA-Sequencing of MCF7 BC cells revealed that cell cycle-related genes were mainly affected by glucose. Connective Tissue Growth Factor (CTGF) was identified as a glucose-induced modulator of cell sensitivity to tamoxifen. Co-culturing MCF7 cells with human adipocytes exposed to HG, enhanced CTGF mRNA levels and reduced tamoxifen responsiveness of BC cells. Inhibition of adipocyte-released IL8 reverted these effects. Interestingly, CTGF immuno-detection in bioptic specimens from women with estrogen receptor positive (ER⁺) BC correlated with hormone therapy resistance, distant metastases, reduced overall and disease-free survival. Thus, glucose affects tamoxifen responsiveness directly modulating CTGF in BC cells, and indirectly promoting IL8 release by adipocytes.

In Vitro Validation of the Hippo Pathway as a Pharmacological Target for Canine Mammary Gland Tumors

Canine mammary tumors (CMTs) are the most common neoplasms in intact female dogs. Some clinical and molecular similarities between certain CMT subtypes and breast cancer make them a potential model for the study of the human disease. As misregulated Hippo signaling is thought to play an important role in breast cancer development and also occurs in CMTs, we sought to determine if Hippo represents a valid pharmacological target for the treatment of CMTs. Six CMT cell lines were assessed for their expression of the Hippo pathway effectors YAP and TAZ and for their sensitivity to verteporfin, an inhibitor of YAP-mediated transcriptional coactivation. Four cell lines that expressed YAP (CMT-9, -12, -28, -47) were found to be very sensitive to verteporfin treatment, which killed the cells through induction of apoptosis with ED50 values of 14-79 nM. Conversely, two YAP-negative cell lines (CF-35, CMT-25) were an order of magnitude more resistant to verteporfin. Verteporfin suppressed the expression of YAP/TAZ target genes, particularly CYR61 and CTGF, which play important roles in breast cancer development. Verteporfin was also able to inhibit cell migration and anchorage-independent growth. Likewise, verteporfin efficiently suppressed tumor cell invasiveness in the CMT-28 and -47 lines, but not in CF-35 cells. Together, our findings provide proof of principle that pharmacological targeting of the Hippo pathway compromises the viability and attenuates the malignant behavior of CMT cells. These results will serve as the basis for the development of novel chemotherapeutic approaches for CMTs that could translate to human medicine.

Targeting of CCN2 suppresses tumor progression and improves chemo-sensitivity in urothelial bladder cancer

Urothelial bladder cancer (UBC) is the most common urinary neoplasm in China. CCN family protein 2 (CCN2), a cysteine-rich matricellular protein, is abnormally expressed in several cancer types and involved in tumor progression or chemo-resistance. However, detailed expression patterns and effects of CCN2 in UBC still remain unknown. We found that down-regulation of CCN2 suppressed proliferation, migration and invasion of UBC cells in vitro and targeting of CCN2 decelerated xenograft growth in vivo. When treated with mitomycin C (MMC), CCN2-scilencing UBC cells showed lower survival and higher apoptotic rates and these effects were probably mediated via inactivation of Akt and Erk pathways. We also demonstrated the clinical significance of CCN2 expression, which was higher in UBC tissues and associated with advanced tumor stage and high pathologic grade. Taken together, our data suggest that CCN2 is an oncogene in UBC and might serve as a matricellular target for improving chemotherapeutic efficacy.

Connective tissue growth factor promotes temozolomide resistance in glioblastoma through TGF-β1-dependent activation of Smad/ERK signaling

Limited benefits and clinical utility of temozolomide (TMZ) for glioblastoma (GB) are frequently compromised by the development of acquired drug resistance. Overcoming TMZ resistance and uncovering the underlying mechanisms are challenges faced during GB chemotherapy. In this study, we reported that connective tissue growth factor (CTGF) was associated with GB chemoresistance and significantly upregulated in TMZ-treated GB cells. CTGF knockdown promoted TMZ-induced cell apoptosis and enhanced chemosensitivity, whereas its overexpression markedly conferred TMZ resistance in vitro and in vivo. Moreover, CTGF promoted TMZ resistance through stem-like properties acquisition and CD44 interference reversed the CTGF-induced TMZ resistance. Mechanistically, further investigation revealed that the TMZ-induced CTGF upregulation was tissue growth factor (TGF-β) dependent, and regulated by TGF-β1 activation through Smad and ERK1/2 signaling. Together, our results suggest a pivotal role of CTGF-mediated TMZ resistance through TGF-β1-dependent activation of Smad/ERK signaling pathways. These data provide us insights for identifying potential targets that are beneficial for overcoming TMZ resistance in GB.

CTGF enhances resistance to 5-FU-mediating cell apoptosis through FAK/MEK/ERK signal pathway in colorectal cancer

Colorectal cancer (CRC) is one of the most commonly diagnosed cancers among both males and females; the chemotherapy drug 5-fluorouracil (5-FU) is one of a doctors’ first lines of defense against CRC. However, therapeutic failures are common because of the emergence of drug resistance. Connective tissue growth factor (CTGF) is a secreted protein that binds to integrins, and regulates the invasiveness and metastasis of certain carcinoma cells. Here, we found that CTGF was upregulated in drug-resistant phenotype of human CRC cells. Overexpression of CTGF enhanced the resistance to 5-FU-induced cell apoptosis. Moreover, downregulating the expression of CTGF promoted the curative effect of chemotherapy and blocked the cell cycle in the G1 phase. We also found that CTGF facilitated resistance to 5-FU-induced apoptosis by increasing the expression of B-cell lymphoma-extra large (Bcl-xL) and survivin. Then we pharmacologically blocked MEK/ERK signal pathway and assessed 5-FU response by MTT assays. Our current results indicate that the expression of phosphorylated forms of MEK/ERK increased in high CTGF expression cells and MEK inhibited increases in 5-FU-mediated apoptosis of resistant CRC cells. Therefore, our data suggest that MEK/ERK signaling contributes to 5-FU resistance through upstream of CTGF, and supports CRC cell growth. Comprehending the molecular mechanism underlying 5-FU resistance may ultimately aid the fight against CRC.

CCN Detection of Cancer Tissues by Immunohistochemistry Staining

CCN family members are involved in many physiologic and pathological functions, and be detected in many different cancer types. Immunohistochemistry (IHC) is an important diagnostic pathology tool to demonstrate protein expression in clinical and research fields. Here, we explain the preparation of sample slides, staining procedure, and the problems that might be met during the time. The differential staining of CCN proteins is shown in breast cancer, oral cancer, lung cancer, colorectal cancer, and gastric cancer.

Characterization of acquired paclitaxel resistance of breast cancer cells and involvement of ABC transporters

Development of taxane resistance has become clinically very important issue. The molecular mechanisms underlying the resistance are still unclear. To address this issue, we established paclitaxel-resistant sublines of the SK-BR-3 and MCF-7 breast cancer cell lines that are capable of long-term proliferation in 100nM and 300nM paclitaxel, respectively. Application of these concentrations leads to cell death in the original counterpart cells. Both sublines are cross-resistant to doxorubicin, indicating the presence of the MDR phenotype. Interestingly, resistance in both paclitaxel-resistant sublines is circumvented by the second-generation taxane SB-T-1216. Moreover, we demonstrated that it was not possible to establish sublines of SK-BR-3 and MCF-7 cells resistant to this taxane. It means that at least the tested breast cancer cells are unable to develop resistance to some taxanes. Employing mRNA expression profiling of all known human ABC transporters and subsequent Western blot analysis of the expression of selected transporters, we demonstrated that only the ABCB1/PgP and ABCC3/MRP3 proteins were up-regulated in both paclitaxel-resistant sublines. We found up-regulation of ABCG2/BCRP and ABCC4 proteins only in paclitaxel-resistant SK-BR-3 cells. In paclitaxel-resistant MCF-7 cells, ABCB4/MDR3 and ABCC2/MRP2 proteins were up-regulated. Silencing of ABCB1 expression using specific siRNA increased significantly, but did not completely restore full sensitivity to both paclitaxel and doxorubicin. Thus we showed a key, but not exclusive, role for ABCB1 in mechanisms of paclitaxel resistance. It suggests the involvement of multiple mechanisms in paclitaxel resistance in tested breast cancer cells.

Dual roles of CCN proteins in breast cancer progression

The tumor microenvironment has a powerful effect on the development and progression of human breast cancer, which may be used therapeutically. Despite efforts to understand the complex role of the tumor microenvironment in breast cancer development, the specific players and their contributions to tumorigenesis need further investigation. The CCN family of matricellular proteins comprises six members (CCN1-6; CYR61, CTGF, NOV, WISP1-3) with central roles in development, inflammation, and tissue repair. CCN proteins also exert functions during pathological processes including fibrosis and cancer by regulating extracellular signals in the cellular environment. Studies have demonstrated that all six CCN proteins exert functions in breast tumorigenesis. Although CCN proteins share a multimodular structure in which most cysteine residues are conserved within structural motifs, they may have opposing functions in breast cancer progression. A better understanding of the functions of each CCN member will assist in the development of specific therapeutic approaches for breast cancer.

Microrna-199a-5p Functions as a Tumor Suppressor via Suppressing Connective Tissue Growth Factor (CTGF) in Follicular Thyroid Carcinoma

Background

The objective of this study was to explore the role of miR-199a-5p in the development of thyroid cancer, including its anti-proliferation effect and downstream signaling pathway.

Material/Methods

We conducted qRT-PCR analysis to detect the expressions of several microRNAs in 42 follicular thyroid carcinoma patients and 42 controls. We identified CTGF as target of miR-491, and viability and cell cycle status were determined in FTC-133 cells transfected with CTGF siRNA, miR-199a mimics, or inhibitors.

Results

We identified an underexpression of miR-199a-5p in follicular thyroid carcinoma tissue samples compared with controls. Then we confirmed CTGF as a target of miR-199a-5p thyroid cells by using informatics analysis and luciferase reporter assay. Additionally, we found that mRNA and protein expression levels of CTGF were both clearly higher in malignant tissues than in benign tissues. miR-199a-5p mimics and CTGF siRNA similarly downregulated the expression of CTGF, and reduced the viability of FTC-133 cells by arresting the cell cycle in G0 phase. Transfection of miR-199a-5p inhibitors increased the expression of CTGF and promoted the viability of the cells by increasing the fraction of cells in G2/M and S phases.

Conclusions

Our study proves that the CTGF gene is a target of miR-199a-5p, demonstrating the negatively related association between CTGF and miR-199a. These findings suggest that miR-199a-5p might be a novel therapeutic target in the treatment of follicular thyroid carcinoma.

Potent effects of dioscin against gastric cancer in vitro and in vivo

BACKGROUND

We previously reported the effect of dioscin on human gastric carcinoma SGC-7901 cells, but its effects on other gastric cancers are still unknown.

PURPOSE

The present paper aimed to demonstrate the activity of dioscin against human gastric carcinoma MGC-803 and MKN-45.

STUDY DESIGN

In our study, MGC-803 and MKN-45 cells were used to examine the effects of dioscin on human gastric carcinoma in vitro. The effects of dioscin against human gastric carcinoma in vivo were accomplished by the xenografts of MGC-803 cells in BALB/c nude mice.

METHODS

AO/EB and DAPI staining, TEM, single cell gel electrophoresis and flow cytometry assays were used in cell experiments. Then, an iTRAQ-based proteomics approach, DNA and siRNA transfection experiments were carried out for mechanism investigation.

RESULTS

In MGC-803 cells, dioscin caused DNA damage and mitochondrial change, induced ROS generation, Ca(2+) release and cell apoptosis, and blocked cell cycle at S phase. In vivo results showed that dioscin significantly suppressed the tumor growth of MGC-803 cell xenografts in nude mice. In addition, dioscin markedly inhibited cell migration, caused Cytochrome c release and adjusted mitochondrial signal pathway. Then, an iTRAQ-based proteomics approach was carried out and 121 differentially expressed proteins were found, in which five biomarkers associated with cell cycle, apoptosis and migration were evaluated. Dioscin significantly up-regulated the levels of GALR-2 and RBM-3, and down-regulated CAP-1, Tribbles-2 and CliC-3. Furthermore, overexpressed DNA transfection of CAP-1 enhanced cell migration and invasion, which was decreased by dioscin. SiRNA to Tribbles-2 affected the protein levels of Bcl-2, Bax and MAPKs, suggesting that dioscin decreased Tribbles-2 level leading to cell apoptosis.

CONCLUSION

Our works confirmed the activity of dioscin against gastric cancer. In addition, this work also provided that dioscin is a new potent candidate for treating gastric cancer in the future.

Multistrand Structure Prediction of Nucleic Acid Assemblies and Design of RNA Switches

RNA is an attractive material for the creation of molecular logic gates that release programmed functionalities only in the presence of specific molecular interaction partners. Here we present HyperFold, a multistrand RNA/DNA structure prediction approach for predicting nucleic acid complexes that can contain pseudoknots. We show that HyperFold also performs competitively compared to other published folding algorithms. We performed a large variety of RNA/DNA hybrid reassociation experiments for different concentrations, DNA toehold lengths, and G+C content and find that the observed tendencies for reassociation correspond well to computational predictions. Importantly, we apply this method to the design and experimental verification of a two-stranded RNA molecular switch that upon binding to a single-stranded RNA toehold disease-marker trigger mRNA changes its conformation releasing an shRNA-like Dicer substrate structure. To demonstrate the concept, connective tissue growth factor (CTGF) mRNA and enhanced green fluorescent protein (eGFP) mRNA were chosen as trigger and target sequences, respectively. In vitro experiments confirm the formation of an RNA switch and demonstrate that the functional unit is being released when the trigger RNA interacts with the switch toehold. The designed RNA switch is shown to be functional in MDA-MB-231 breast cancer cells. Several other switches were also designed and tested. We conclude that this approach has considerable potential because, in principle, it allows the release of an siRNA designed against a gene that differs from the gene that is utilized as a biomarker for a disease state.

ZEB1 turns into a transcriptional activator by interacting with YAP1 in aggressive cancer types

Early dissemination, metastasis and therapy resistance are central hallmarks of aggressive cancer types and the leading cause of cancer-associated deaths. The EMT-inducing transcriptional repressor ZEB1 is a crucial stimulator of these processes, particularly by coupling the activation of cellular motility with stemness and survival properties. ZEB1 expression is associated with aggressive behaviour in many tumour types, but the potent effects cannot be solely explained by its proven function as a transcriptional repressor of epithelial genes. Here we describe a direct interaction of ZEB1 with the Hippo pathway effector YAP, but notably not with its paralogue TAZ. In consequence, ZEB1 switches its function to a transcriptional co-activator of a ‘common ZEB1/YAP target gene set', thereby linking two pathways with similar cancer promoting effects. This gene set is a predictor of poor survival, therapy resistance and increased metastatic risk in breast cancer, indicating the clinical relevance of our findings.

The transcription factors ZEB1 and YAP function in different pathways yet both activate aggressive behaviour in cancer cells. Here, the authors describe that the proteins physically interact and that this changes the transcriptional activity of ZEB1 from a repressor to an activator.

Inorganic Phosphate Prevents Erk1/2 and Stat3 Activation and Improves Sensitivity to Doxorubicin of MDA-MB-231 Breast Cancer Cells

Due to its expression profile, triple-negative breast cancer (TNBC) is refractory to the most effective targeted therapies available for breast cancer treatment. Thus, cytotoxic chemotherapy represents the mainstay of treatment for early and metastatic TNBC. Therefore, it would be greatly beneficial to develop therapeutic approaches that cause TNBC cells to increase their sensitivity to cytotoxic drugs. Inorganic phosphate (Pi) is emerging as an important signaling molecule in many cell types. Interestingly, it has been shown that Pi greatly enhances the sensitivity of human osteosarcoma cell line (U2OS) to doxorubicin. We investigated the effects of Pi on the sensitivity of TNBC cells to doxorubicin and the underlying molecular mechanisms, carrying out flow cytometry-based assays of cell-cycle progression and cell death, MTT assays, direct cell number counting and immunoblotting experiments. We report that Pi inhibits the proliferation of triple-negative MDA-MB-231 breast cancer cells mainly by slowing down cell cycle progression. Interestingly, we found that Pi strongly increases doxorubicin-induced cytotoxicity in MDA-MB-231 cells by apoptosis induction, as revealed by a marked increase of sub-G1 population, Bcl-2 downregulation, caspase-3 activation and PARP cleavage. Remarkably, Pi/doxorubicin combination-induced cytotoxicity was dynamically accompanied by profound changes in Erk1/2 and Stat3 protein and phosphorylation levels. Altogether, our data enforce the evidence of Pi acting as a signaling molecule in MDA-MB-231 cells, capable of inhibiting Erk and Stat3 pathways and inducing sensitization to doxorubicin of TNBC cells, and suggest that targeting Pi levels at local sites might represent the rationale for developing effective and inexpensive strategies for improving triple-negative breast cancer therapy.

Enhanced cytotoxicity in triple-negative and estrogen receptor‑positive breast adenocarcinoma cells due to inhibition of the transient receptor potential melastatin-2 channel

We previously demonstrated a unique protective role for the transient receptor potential, melastatin-2 (TRPM2) cation channel in breast cancer cells. In the present study, we investigated the chemotherapeutic effects elicited by inhibiting this protective role in metastatic breast adenocarcinoma cells. TRPM2 inhibition led to dose-dependent increases in MDA-MB-231 breast adenocarcinoma cell death after treatment with doxorubicin or the DNA-methylating agent, N-methyl-N'-nitro-N-nitrosoguanidine. Similar results were observed after RNAi silencing of TRPM2 in these cells after doxorubicin treatment. However, TRPM2 RNAi silencing also led to increased MCF-7 breast adenocarcinoma cell death after tamoxifen treatment, yet not in non-cancerous human mammary epithelial cells. These results thus revealed that TRPM2 inhibition selectively increased cytotoxicity in a triple-negative and an estrogen receptor-positive breast cancer cell line, with minimal deleterious effects in non-cancerous breast cells. Analysis of DNA damage revealed enhanced DNA damage levels in MCF-7 cells treated with doxorubicin due to TRPM2 inhibition. Analysis of cell death demonstrated that inhibition of apoptosis, caspase-independent cell death or autophagy failed to significantly reduce cell death induced by TRPM2 inhibition and chemotherapy. These results indicate that TRPM2 inhibition activates alternative pathways of cell death in breast cancer cells. Taken together, our results provide significant evidence that TRPM2 inhibition is a potential strategy to induce triple-negative and estrogen receptor-positive breast adenocarcinoma cell death via alternative cell death pathways. This is expected to provide a basis for inhibiting TRPM2 for the improved treatment of breast cancer, which potentially includes treating breast tumors that are resistant to chemotherapy due to their evasion of apoptosis.

YAP activation protects urothelial cell carcinoma from treatment-induced DNA damage

Current standard of care for muscle-invasive urothelial cell carcinoma (UCC) is surgery along with perioperative platinum-based chemotherapy. UCC is sensitive to cisplatin-based regimens, but acquired resistance eventually occurs, and a subset of tumors is intrinsically resistant. Thus, there is an unmet need for new therapeutic approaches to target chemotherapy-resistant UCC. Yes-associated protein (YAP) is a transcriptional co-activator that has been associated with bladder cancer progression and cisplatin resistance in ovarian cancer. In contrast, YAP has been shown to induce DNA damage associated apoptosis in non-small cell lung carcinoma. However, no data have been reported on the YAP role in UCC chemo-resistance. Thus, we have investigated the potential dichotomous role of YAP in UCC response to chemotherapy utilizing two patient-derived xenograft models recently established. Constitutive expression and activation of YAP inversely correlated with in vitro and in vivo cisplatin sensitivity. YAP overexpression protected while YAP knock-down sensitized UCC cells to chemotherapy and radiation effects via increased accumulation of DNA damage and apoptosis. Furthermore, pharmacological YAP inhibition with verteporfin inhibited tumor cell proliferation and restored sensitivity to cisplatin. In addition, nuclear YAP expression was associated with poor outcome in UCC patients who received perioperative chemotherapy. In conclusion, these results suggest that YAP activation exerts a protective role and represents a pharmacological target to enhance the anti-tumor effects of DNA damaging modalities in the treatment of UCC.

Up-regulation of the Hippo pathway effector TAZ renders lung adenocarcinoma cells harboring EGFR-T790M mutation resistant to gefitinib

Background

The T790M mutation of epithelial growth factor receptor (EGFR) is a major cause of the acquired resistance to EGFR tyrosine kinase inhibitor (EGFR-TKIs) treatment for lung cancer patients. The Hippo pathway effector, TAZ, has emerged as a key player in organ growth and tumorigenesis, including lung cancer.

Results

In this study, we have discovered high TAZ expression in non-small cell lung cancer (NSCLC) cells harboring dual mutation and TAZ depletion sensitized their response to EGFR-TKIs. Mechanistically, knockdown of TAZ in T790M-induced resistant cells leaded to reduced anchorage-independent growth in vitro, tumor formation and resistance to gefitinib in vivo, correlated with epithelial-mesenchymal transition (EMT) and suppressed migration and invasion. Furthermore, we confirmed CTGF and AXL, novel EMT markers and potential therapeutic targets for overcoming EGFR inhibitor resistance, as directly transcriptional targets of TAZ.

Conclusions

Taken together, this study suggests that expression of TAZ is an intrinsic mechanism of T790M-induced resistance in response to EGFR-TKIs. Combinational targeting on both EGFR and TAZ may enhance the efficacy of EGFR-TKIs in acquired resistance of NSCLC.

Electronic supplementary material

The online version of this article (doi:10.1186/2045-3701-5-7) contains supplementary material, which is available to authorized users.

c-Abl antagonizes the YAP oncogenic function

YES-associated protein (YAP) is a central transcription coactivator that functions as an oncogene in a number of experimental systems. However, under DNA damage, YAP activates pro-apoptotic genes in conjunction with p73. This program switching is mediated by c-Abl (Abelson murine leukemia viral oncogene) via phosphorylation of YAP at the Y357 residue (pY357). YAP as an oncogene coactivates the TEAD (transcriptional enhancer activator domain) family transcription factors. Here we asked whether c-Abl regulates the YAP-TEAD functional module. We found that DNA damage, through c-Abl activation, specifically depressed YAP-TEAD-induced transcription. Remarkably, c-Abl counteracts YAP-induced transformation by interfering with the YAP-TEAD transcriptional program. c-Abl induced TEAD1 phosphorylation, but the YAP-TEAD complex remained unaffected. In contrast, TEAD coactivation was compromised by phosphomimetic YAP Y357E mutation but not Y357F, as demonstrated at the level of reporter genes and endogenous TEAD target genes. Furthermore, YAP Y357E also severely compromised the role of YAP in cell transformation, migration, anchorage-independent growth, and epithelial-to-mesenchymal transition (EMT) in human mammary MCF10A cells. These results suggest that YAP pY357 lost TEAD transcription activation function. Our results demonstrate that YAP pY357 inactivates YAP oncogenic function and establish a role for YAP Y357 phosphorylation in cell-fate decision.