Lipophilic statins inhibit YAP nuclear localization, co-activator activity and colony formation in pancreatic cancer cells and prevent the initial stages of pancreatic ductal adenocarcinoma in KrasG12D mice

The mechanopathology of the tumor microenvironment: detection techniques, molecular mechanisms and therapeutic opportunities

The mechanical properties of the tumor microenvironment (TME) undergo significant changes during tumor growth, primarily driven by alterations in extracellular (ECM) stiffness and tumor viscoelasticity. These mechanical changes not only promote tumor progression but also hinder therapeutic efficacy by impairing drug delivery and activating mechanotransduction pathways that regulate crucial cellular processes such as migration, proliferation, and resistance to therapy. In this review, we examine the mechanisms through which tumor cells sense and transmit mechanical signals to maintain homeostasis in the biomechanically altered TME. We explore current computational modelling strategies for mechanotransduction pathways, highlighting the need for developing models that incorporate additional components of the mechanosignaling machinery. Furthermore, we review available methods for measuring the mechanical properties of tumors in clinical settings and strategies aiming at restoring the TME and blocking deregulated mechanotransduction pathways. Finally, we propose that proper characterization and a deeper understanding of the mechanical landscape of the TME, both at the tissue and cellular levels, are essential for developing therapeutic strategies that account for the influence of mechanical forces on treatment efficacy.

BADGER: biologically-aware interpretable differential gene expression ranking model

Motivation

Understanding which genes are significantly affected by drugs is crucial for drug repurposing, as drugs targeting specific pathways in one disease might be effective in another with similar genetic profiles. By analyzing gene expression changes in cells before and after drug treatment, we can identify the genes most impacted by drugs.

Results

The Biologically-Aware Interpretable Differential Gene Expression Ranking (BADGER) model is an interpretable model designed to predict gene expression changes resulting from interactions between cancer cell lines and chemical compounds. The model enhances explainability through integration of prior knowledge about drug targets via pathway information, handles novel cancer cell lines through similarity-based embedding, and employs three attention blocks that mimic the cascading effects of chemical compounds. This model overcomes previous limitations of cell line range and explainability constraints in drug-cell response studies. The model demonstrates superior performance over baselines in both unseen cell and unseen pair split evaluations, showing robust prediction capabilities for untested drug-cell line combinations.

Availability and implementation

This makes it particularly valuable for drug repurposing scenarios, especially in developing therapeutic plans for new or resistant diseases by leveraging similarities with other diseases. All code and data used in this study are available at https://github.com/dmis-lab/BADGER.git.

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.

Integrated proteomics and metabolomics analyses reveal new insights into the antitumor effects of valproic acid plus simvastatin combination in a prostate cancer xenograft model associated with downmodulation of YAP/TAZ signaling

BACKGROUND

Despite advancements in therapeutic approaches, including taxane-based chemotherapy and androgen receptor-targeting agents, metastatic castration-resistant prostate cancer (mCRPC) remains an incurable tumor, highlighting the need for novel strategies that can target the complexities of this disease and bypass the development of drug resistance mechanisms. We previously demonstrated the synergistic antitumor interaction of valproic acid (VPA), an antiepileptic agent with histone deacetylase inhibitory activity, with the lipid-lowering drug simvastatin (SIM). This combination sensitizes mCRPC cells to docetaxel treatment both in vitro and in vivo by targeting the cancer stem cell compartment via mevalonate pathway/YAP axis modulation.

METHODS

Here, using a combined proteomic and metabolomic/lipidomic approach, we characterized tumor samples derived from 22Rv1 mCRPC cell-xenografted mice treated with or without VPA/SIM and performed an in-depth bioinformatics analysis.

RESULTS

We confirmed the specific impact of VPA/SIM on the Hippo-YAP signaling pathway, which is functionally related to the modulation of cancer-related extracellular matrix biology and metabolic reprogramming, providing further insights into the molecular mechanism of the antitumor effects of VPA/SIM.

CONCLUSIONS

In this study, we present an in-depth exploration of the potential to repurpose two generic, safe drugs for mCRPC treatment, valproic acid (VPA) and simvastatin (SIM), which already show antitumor efficacy in combination, primarily affecting the cancer stem cell compartment via MVP/YAP axis modulation. Bioinformatics analysis of the LC‒MS/MS and 1H‒NMR metabolomics/lipidomics results confirmed the specific impact of VPA/SIM on Hippo-YAP.

PNLIPRP1 Hypermethylation in Exocrine Pancreas Links Type 2 Diabetes and Cholesterol Metabolism

We postulated that type 2 diabetes (T2D) predisposes patients to exocrine pancreatic diseases through (epi)genetic mechanisms. We explored the methylome (using MethylationEPIC arrays) of the exocrine pancreas in 141 donors, assessing the impact of T2D. An epigenome-wide association study of T2D identified hypermethylation in an enhancer of the pancreatic lipase-related protein 1 (PNLIPRP1) gene, associated with decreased PNLIPRP1 expression. PNLIPRP1 null variants (found in 191,000 participants in the UK Biobank) were associated with elevated glycemia and LDL cholesterol. Mendelian randomization using 2.5M SNP Omni arrays in 111 donors revealed that T2D was causal of PNLIPRP1 hypermethylation, which in turn was causal of LDL cholesterol. Additional AR42J rat exocrine cell analyses demonstrated that Pnliprp1 knockdown induced acinar-to-ductal metaplasia, a known prepancreatic cancer state, and increased cholesterol levels, reversible with statin. This (epi)genetic study suggests a role for PNLIPRP1 in human metabolism and exocrine pancreatic function, with potential implications for pancreatic diseases.

ARTICLE HIGHLIGHTS

Targeting a chemo-induced adaptive signaling circuit confers therapeutic vulnerabilities in pancreatic cancer

Advanced pancreatic ductal adenocarcinomas (PDACs) respond poorly to all therapies, including the first-line treatment, chemotherapy, the latest immunotherapies, and KRAS-targeting therapies. Despite an enormous effort to improve therapeutic efficacy in late-stage PDAC patients, effective treatment modalities remain an unmet medical challenge. To change the status quo, we explored the key signaling networks underlying the universally poor response of PDAC to therapy. Here, we report a previously unknown chemo-induced symbiotic signaling circuit that adaptively confers chemoresistance in patients and mice with advanced PDAC. By integrating single-cell transcriptomic data from PDAC mouse models and clinical pathological information from PDAC patients, we identified Yap1 in cancer cells and Cox2 in stromal fibroblasts as two key nodes in this signaling circuit. Co-targeting Yap1 in cancer cells and Cox2 in stroma sensitized PDAC to Gemcitabine treatment and dramatically prolonged survival of mice bearing late-stage PDAC, whereas simultaneously inhibiting Yap1 and Cox2 only in cancer cells was ineffective. Mechanistically, chemotherapy triggers non-canonical Yap1 activation by nemo-like kinase in 14-3-3ζ-overexpressing PDAC cells and increases secretion of CXCL2/5, which bind to CXCR2 on fibroblasts to induce Cox2 and PGE2 expression, which reciprocally facilitate PDAC cell survival. Finally, analyses of PDAC patient data revealed that patients who received Statins, which inhibit Yap1 signaling, and Cox2 inhibitors (including Aspirin) while receiving Gemcitabine displayed markedly prolonged survival compared to others. The robust anti-tumor efficacy of Statins and Aspirin, which co-target the chemo-induced adaptive circuit in the tumor cells and stroma, signifies a unique therapeutic strategy for PDAC.

Extracellular vesicles miR-31-5p promotes pancreatic cancer chemoresistance via regulating LATS2-Hippo pathway and promoting SPARC secretion from pancreatic stellate cells

Pancreatic cancer remains one of the most lethal malignant diseases. Gemcitabine-based chemotherapy is still one of the first-line systemic treatments, but chemoresistance occurs in the majority of patients. Recently, accumulated evidence has demonstrated the role of the tumour microenvironment in promoting chemoresistance. In the tumour microenvironment, pancreatic stellate cells (PSCs) are among the main cellular components, and extracellular vesicles (EVs) are common mediators of cell‒cell communication. In this study, we showed that SP1-transcribed miR-31-5p not only targeted LATS2 in pancreatic cancer cells but also regulated the Hippo pathway in PSCs through EV transfer. Consequently, PSCs synthesized and secreted protein acidic and rich in cysteins (SPARC), which was preferentially expressed in stromal cells, stimulating Extracellular Signal regulated kinase (ERK) signalling in pancreatic cancer cells. Therefore, pancreatic cancer cell survival and chemoresistance were improved due to both the intrinsic Hippo pathway regulated by miR-31-5p and external SPARC-induced ERK signalling. In mouse models, miR-31-5p overexpression in pancreatic cancer cells promoted the chemoresistance of coinjected xenografts. In a tissue microarray, pancreatic cancer patients with higher miR-31-5p expression had shorter overall survival. Therefore, miR-31-5p regulates the Hippo pathway in multiple cell types within the tumour microenvironment via EVs, ultimately contributing to the chemoresistance of pancreatic cancer cells.

A review on decoding the roles of YAP/TAZ signaling pathway in cardiovascular diseases: Bridging molecular mechanisms to therapeutic insights

Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ) serve as transcriptional co-activators that dynamically shuttle between the cytoplasm and nucleus, resulting in either the suppression or enhancement of their downstream gene expression. Recent emerging evidence demonstrates that YAP/TAZ is strongly implicated in the pathophysiological processes that contribute to cardiovascular diseases (CVDs). In the cardiovascular system, YAP/TAZ is involved in the orchestration of a range of biological processes such as oxidative stress, inflammation, proliferation, and autophagy. Furthermore, YAP/TAZ has been revealed to be closely associated with the initiation and development of various cardiovascular diseases, including atherosclerosis, pulmonary hypertension, myocardial fibrosis, cardiac hypertrophy, and cardiomyopathy. In this review, we delve into recent studies surrounding YAP and TAZ, along with delineating their roles in contributing to the pathogenesis of CVDs with a link to various physiological processes in the cardiovascular system. Additionally, we highlight the current potential drugs targeting YAP/TAZ for CVDs therapy and discuss their challenges for translational application. Overall, this review may offer novel insights for understanding and treating cardiovascular disorders.

Simvastatin Overcomes Resistance to Tyrosine Kinase Inhibitors in Patient-derived, Oncogene-driven Lung Adenocarcinoma Models

There is an unmet clinical need to develop novel strategies to overcome resistance to tyrosine kinase inhibitors (TKI) in patients with oncogene-driven lung adenocarcinoma (LUAD). The objective of this study was to determine whether simvastatin could overcome TKI resistance using the in vitro and in vivo LUAD models. Human LUAD cell lines, tumor cells, and patient-derived xenograft (PDX) models from TKI-resistant LUAD were treated with simvastatin, either alone or in combination with a matched TKI. Tumor growth inhibition was measured by the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay and expression of molecular targets was assessed by immunoblots. Tumors were assessed by histopathology, IHC stain, immunoblots, and RNA sequencing. We found that simvastatin had a potent antitumor effect in tested LUAD cell lines and PDX tumors, regardless of tumor genotypes. Simvastatin and TKI combination did not have antagonistic cytotoxicity in these LUAD models. In an osimertinib-resistant LUAD PDX model, simvastatin and osimertinib combination resulted in a greater reduction in tumor volume than simvastatin alone (P < 0.001). Immunoblots and IHC stain also confirmed that simvastatin inhibited TKI targets. In addition to inhibiting 3-hydroxy-3-methyl-glutaryl-CoA (HMG-CoA) reductase, RNA sequencing and Western blots identified the proliferation, migration, and invasion-related genes (such as PI3K/Akt/mTOR, YAP/TAZ, focal adhesion, extracellular matrix receptor), proteasome-related genes, and integrin (α3β1, αvβ3) signaling pathways as the significantly downregulated targets in these PDX tumors treated with simvastatin and a TKI. The addition of simvastatin is a safe approach to overcome acquired resistance to TKIs in several oncogene-driven LUAD models, which deserve further investigation.

Upregulated Matrisomal Proteins and Extracellular Matrix Mechanosignaling Underlie Obesity-Associated Promotion of Pancreatic Ductal Adenocarcinoma

Diet-induced obesity (DIO) promotes pancreatic ductal adenocarcinoma (PDAC) in mice expressing KRasG12D in the pancreas (KC mice), but the precise mechanisms remain unclear. Here, we performed multiplex quantitative proteomic and phosphoproteomic analysis by liquid chromatography-tandem mass spectrometry and further bioinformatic and spatial analysis of pancreas tissues from control-fed versus DIO KC mice after 3, 6, and 9 months. Normal pancreatic parenchyma and associated proteins were steadily eliminated and the novel proteins, phosphoproteins, and signaling pathways associated with PDAC tumorigenesis increased until 6 months, when most males exhibited cancer, but females did not. Differentially expressed proteins and phosphoproteins induced by DIO revealed the crucial functional role of matrisomal proteins, which implies the roles of upstream regulation by TGFβ, extracellular matrix-receptor signaling to downstream PI3K-Akt-mTOR-, MAPK-, and Yap/Taz activation, and crucial effects in the tumor microenvironment such as metabolic alterations and signaling crosstalk between immune cells, cancer-associated fibroblasts (CAFs), and tumor cells. Staining tissues from KC mice localized the expression of several prognostic PDAC biomarkers and elucidated tumorigenic features, such as robust macrophage infiltration, acinar-ductal metaplasia, mucinous PanIN, distinct nonmucinous atypical flat lesions (AFLs) surrounded by smooth muscle actin-positive CAFs, invasive tumors with epithelial-mesenchymal transition arising close to AFLs, and expanding deserted areas by 9 months. We next used Nanostring GeoMX to characterize the early spatial distribution of specific immune cell subtypes in distinct normal, stromal, and PanIN areas. Taken together, these data richly contextualize DIO promotion of Kras-driven PDAC tumorigenesis and provide many novel insights into the signaling pathways and processes involved.

Mutant p53 murine oviductal epithelial cells induce progression of high-grade serous carcinoma and are most sensitive to simvastatin therapy in vitro and in vivo

High-grade serous carcinoma (HGSC) is the most common and aggressive subtype of epithelial ovarian cancer, characterized by gain-of-function TP53 mutations originating in the fallopian tube epithelium. Therapeutic intervention occurs at advanced metastatic disease, due to challenges in early-stage diagnosis, with common disease recurrence and therapy resistance despite initial therapy success. The mevalonate pathway is exploited by many cancers and is potently inhibited by statin drugs. Statins have shown anti-cancer activity in many, but not all cancers. Here, we investigated the role of p53 status in relation to mevalonate pathway signaling in murine oviductal epithelial (OVE) cells and identified OVE cell sensitivity to statin inhibition. We found that p53R175H mutant and Trp53 knockout OVE cells have increased mevalonate pathway signaling compared to p53 wild-type OVE cells. Through orthotopic implantation to replicate the fallopian tube origin of HGSC, p53R175H mutant cells upregulated the mevalonate pathway to drive progression to advanced-stage ovarian cancer, and simvastatin treatment abrogated this effect. Additionally, simvastatin was more efficacious at inhibiting cell metabolic activity in OVE cells than atorvastatin, rosuvastatin and pravastatin. In vitro, simvastatin demonstrated potent effects on cell proliferation, apoptosis, invasion and migration in OVE cells regardless of p53 status. In vivo, simvastatin induced ovarian cancer disease regression through decreased primary ovarian tumor weight and increased apoptosis. Simvastatin also significantly increased cytoplasmic localization of HMG-CoA reductase in ovarian tumors. Downstream of the mevalonate pathway, simvastatin had no effect on YAP or small GTPase activity. This study suggests that simvastatin can induce anti-tumor effects and could be an important inhibitor of ovarian cancer progression.

Association between statins exposure and risk of skin cancer: an updated meta-analysis

This study aimed to investigate the relationship between statin (lipophilic statin and hydrophilic statin) exposure and the risk of skin cancer. The incidence of skin cancer under statin exposure was used as the primary outcome, and the relevant studies were screened from Web of Science, PubMed, Cochrane Library, and EBSCO electronic database until September 2022. Ten observational studies and two randomized controlled trials (RCTs) were included. The statistical results indicated that in lipophilic statins, the exposed group had a higher risk of skin cancer than the non-exposed group (OR: 1.09, P = 0.003). However, compared with the non-exposed group, there was no significant difference between hydrophilic statins exposure and the incidence of skin cancer (OR: 1.02, P = 0.341). Further subgroup analysis of the subtypes of statins revealed that compared with the non-exposed group, exposure to lovastatin (OR: 1.18, P = 0.048) or simvastatin (OR: 1.11, P < 0.001) was a risk factor for skin cancer. Besides, subgroup analysis based on the subtypes of skin cancer demonstrated that the risks of melanoma (OR: 1.13, P = 0.009), basal cell carcinoma (BCC) (OR: 1.05, P = 0.036), and squamous cell carcinoma (SCC) (OR: 1.13, P = 0.026) under lipophilic statin exposure were significantly higher than those in the non-exposed group. On the contrary, compared with the non-exposed group, the risk of BCC was significantly reduced under the exposure of hydrophilic statins (OR: 0.93, P = 0.031). This study showed that the relationship between statin exposure and skin cancer risk was affected by the subtypes of statins and skin cancer subtypes.

Low dosage combination treatment with metformin and simvastatin inhibits obesity-promoted pancreatic cancer development in male KrasG12D mice

Pancreatic ductal adenocarcinoma (PDAC), a highly lethal disease with limited therapeutic options, may benefit from repurposing of FDA-approved drugs in preventive or interceptive strategies in high-risk populations. Previous animal studies demonstrated that the use of metformin and statins as single agents at relatively high doses restrained PDAC development. Here, four-week-old mice expressing KrasG12D in all pancreatic lineages (KC mice) and fed an obesogenic high fat, high calorie diet that promotes early PDAC development were randomized onto low dosage metformin, simvastatin, or both drugs in combination administered orally. Dual treatment attenuated weight gain, fibro-inflammation, and development of advanced PDAC precursor lesions (pancreatic intraepithelial neoplasia [PanIN]-3) in male KC mice, without significant effect in females or when administered individually. Dual-treated KC mice had reduced proliferation of PanIN cells and decreased transcriptional activity of the Hippo effectors, YAP and TAZ, which are important regulators of PDAC development. Metformin and simvastatin also synergistically inhibited colony formation of pancreatic cancer cells in vitro. Together, our data demonstrated that a combination of low doses of metformin and simvastatin inhibits PDAC development and imply that both drugs are promising agents for being tested in clinical trials for preventing pancreatic cancer progression.

Lipophilic statins inhibit YAP coactivator transcriptional activity in HCC cells through Rho-mediated modulation of actin cytoskeleton

Hepatocellular carcinoma (HCC) is the third leading cause of liver-related death. Lipophilic statins have been associated with a decrease in HCC incidence, raising the possibility of their use as chemoprevention agents. The Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ) have emerged as an important pro-oncogenic mechanism in HCC. Statins modulate YAP/TAZ in other solid tumors, but few studies have assessed their mechanisms in HCC. We aimed to delineate how lipophilic statins regulate YAP protein localization by interrogating the mevalonate pathway in a stepwise manner using pharmacological and genetical approaches in HCC cells. Huh7 and Hep3B HCC cells were treated with the lipophilic statins cerivastatin and atorvastatin. YAP protein localization was determined using quantitative immunofluorescence (IF) imaging. The gene expression of CTGF and CYR61, known YAP/TEA-domain DNA-binding factor (TEAD)-regulated genes, was measured using quantitative real-time PCR. Rescue experiments were conducted using metabolites of the mevalonate pathway including mevalonic acid and geranylgeranyl pyrophosphate (GG-PP). The cellular cytoskeleton was assessed using F-actin IF staining. YAP protein was extruded from the nucleus to the cytoplasm with statin treatment. Consistently, CTGF and CYR61 mRNA expression significantly decreased with statins. Cytoskeletal structure was also compromised with statins. Gene expression, YAP protein localization, and cytoskeletal structure were all restored to baseline with exogenous GG-PP but not with other metabolites of the mevalonate pathway. Direct Rho GTPase inhibitor treatment mirrored the statin effects on YAP. YAP protein localization is regulated by lipophilic statins via Rho GTPases, causing cytoskeletal structural changes and is independent of cholesterol metabolites.NEW & NOTEWORTHY Statins are widely used for the treatment of cardiovascular diseases. Recently, their use has been associated with a decrease in the incidence of hepatocellular carcinoma (HCC); however, their mechanism(s) has remained elusive. In this study, we delineate the mechanism by which statins affect the Yes-associated protein (YAP), which has emerged as a key oncogenic pathway in HCC. We investigate each step of the mevalonate pathway and demonstrate that statins regulate YAP via Rho GTPases.

The Hippo Pathway Effectors YAP/TAZ-TEAD Oncoproteins as Emerging Therapeutic Targets in the Tumor Microenvironment

Various cancer cell-associated intrinsic and extrinsic inputs act on YAP/TAZ proteins to mediate the hyperactivation of the TEAD transcription factor-based transcriptome. This YAP/TAZ-TEAD activity can override the growth-limiting Hippo tumor-suppressor pathway that maintains normal tissue homeostasis. Herein, we provide an integrated summary of the contrasting roles of YAP/TAZ during normal tissue homeostasis versus tumor initiation and progression. In addition to upstream factors that regulate YAP/TAZ in the TME, critical insights on the emerging functions of YAP/TAZ in immune suppression and abnormal vasculature development during tumorigenesis are illustrated. Lastly, we discuss the current methods that intervene with the YAP/TAZ-TEAD oncogenic signaling pathway and the emerging applications of combination therapies, gut microbiota, and epigenetic plasticity that could potentiate the efficacy of chemo/immunotherapy as improved cancer therapeutic strategies.

Insights into recent findings and clinical application of YAP and TAZ in cancer

Decades of research have mapped out the basic mechanics of the Hippo pathway. The paralogues Yes-associated protein (YAP) and transcriptional co-activator with PDZ-binding motif (TAZ), as the central transcription control module of the Hippo pathway, have long been implicated in the progression of various human cancers. The current literature regarding oncogenic YAP and TAZ activities consists mostly of context-specific mechanisms and treatments of human cancers. Furthermore, a growing number of studies demonstrate tumour-suppressor functions of YAP and TAZ. In this Review we aim to synthesize an integrated perspective of the many disparate findings regarding YAP and TAZ in cancer. We then conclude with the various strategies for targeting and treating YAP- and TAZ-dependent cancers.

Association of Statin Use With Risk of Liver Disease, Hepatocellular Carcinoma, and Liver-Related Mortality

IMPORTANCE

Given the burden of chronic liver disease on the health care system, more information on the hepatoprotective association of statins in the general population is needed.

OBJECTIVE

To examine whether regular statin use is associated with a reduction in liver disease, particularly hepatocellular carcinoma (HCC) and liver-related deaths, in the general population.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study used data from the UK Biobank (UKB) (individuals aged 37-73 years) collected from baseline (2006-2010) to the end of follow-up in May 2021, from the TriNetX cohort (individuals aged 18-90 years) enrolled from baseline (2011-2020) until end of follow-up in September 2022, and from the Penn Medicine Biobank (PMBB) (individuals aged 18-102 years) with ongoing enrollment starting in 2013 to the end of follow-up in December 2020. Individuals were matched using propensity score matching according to the following criteria: age, sex, body mass index, ethnicity, diabetes with or without insulin or biguanide use, hypertension, ischemic heart disease, dyslipidemia, aspirin use, and number of medications taken (UKB only). Data analysis was performed from April 2021 to April 2023.

EXPOSURE

Regular statin use.

MAIN OUTCOMES AND MEASURES

Primary outcomes were liver disease and HCC development as well as liver-associated death.

RESULTS

A total of 1 785 491 individuals were evaluated after matching (aged 55 to 61 years on average, up to 56% men, and up to 49% women). A total of 581 cases of liver-associated death, 472 cases of incident HCC, and 98 497 new liver diseases were registered during the follow-up period. Individuals were aged 55-61 years on average, with a slightly higher proportion of men (up to 56%). In UKB individuals (n = 205 057) without previously diagnosed liver disease, statin users (n = 56 109) had a 15% lower hazard ratio (HR) for the association of developing a new liver disease (HR, 0.85; 95% CI, 0.78-0.92; P < .001). In addition, statin users demonstrated a 28% lower HR for the association with liver-related death (HR, 0.72; 95% CI, 0.59-0.88; P = .001) and a 42% lower HR for the development of HCC (HR, 0.58; 95% CI, 0.35-0.96; P = .04). In TriNetX individuals (n = 1 568 794), the HR for the association of HCC was reduced even further for statin users (HR, 0.26; 95% CI, 0.22-0.31; P = .003). The hepatoprotective association of statins was time and dose dependent, with a significant association in PMBB individuals (n = 11 640) for incident liver diseases after 1 year of statin use (HR, 0.76; 95% CI, 0.59-0.98; P = .03). Taking statins was particularly beneficial in men, individuals with diabetes, and individuals with a high Fibrosis-4 index at baseline. Carriers of the heterozygous minor allele of PNPLA3 rs738409 benefited from statin use and had a 69% lower HR for the association with HCC (UKB HR, 0.31; 95% CI, 0.11-0.85; P = .02).

CONCLUSIONS AND RELEVANCE

This cohort study indicates substantial preventive associations of statins against liver disease, with an association with duration and dose of intake.

Opposite Effects of Src Family Kinases on YAP and ERK Activation in Pancreatic Cancer Cells: Implications for Targeted Therapy

Pancreatic ductal adenocarcinoma (PDAC) remains an aggressive disease that is expected to become the second cause of cancer fatalities during the next decade. As therapeutic options are limited, novel targets, and agents for therapeutic intervention are urgently needed. Previously, we identified potent positive crosstalk between insulin/IGF-1 receptors and G protein-coupled (GPCR) signaling systems leading to mitogenic signaling in PDAC cells. Here, we show that a combination of insulin and the GPCR agonist neurotensin induced rapid activation of Src family of tyrosine kinases (SFK) within PANC-1 cells, as shown by FAK phosphorylation at Tyr576/577 and Tyr861, sensitive biomarkers of SFK activity within intact cells and Src416 autophosphorylation. Crucially, SFKs promoted YAP nuclear localization and phosphorylation at Tyr357, as shown by using the SFK inhibitors dasatinib, saracatinib, the preferential YES1 inhibitor CH6953755, siRNA-mediated knockdown of YES1, and transfection of epitogue-tagged YAP mutants in PANC-1 and Mia PaCa-2 cancer cells, models of the aggressive squamous subtype of PDAC. Surprisingly, our results also demonstrate that exposure to SFK inhibitors, including dasatinib or knockdown of YES and Src induces ERK overactivation in PDAC cells. Dasatinib-induced ERK activation was completely abolished by exposure to the FDA-approved MEK inhibitor trametinib. A combination of dasatinib and trametinib potently and synergistically inhibited colony formation by PDAC cells and suppressed the growth of Mia PaCa-2 cells xenografted into the flank of nude mice. The results provide rationale for considering a combination(s) of FDA-approved SFK (dasatinib) and MEK (e.g., trametinib) inhibitors in prospective clinical trials for the treatment of PDAC.

Targeting the Hippo Pathway in Gastric Cancer and Other Malignancies in the Digestive System: From Bench to Bedside

The Hippo pathway is an evolutionally conserved signaling cascade that controls organ size and tissue regeneration under physiological conditions, and its aberrations have been well studied to promote tumor initiation and progression. Dysregulation of the Hippo tumor suppressor signaling frequently occurs in gastric cancer (GC) and other solid tumors and contributes to cancer development through modulating multiple aspects, including cell proliferation, survival, metastasis, and oncotherapy resistance. In the clinic, Hippo components also possess diagnostic and prognostic values for cancer patients. Considering its crucial role in driving tumorigenesis, targeting the Hippo pathway may greatly benefit developing novel cancer therapies. This review summarizes the current research progress regarding the core components and regulation of the Hippo pathway, as well as the mechanism and functional roles of their dysregulation in gastrointestinal malignancies, especially in GC, and discusses the therapeutic potential of targeting the Hippo pathway against cancers.

Targeting the Hippo/YAP/TAZ signalling pathway: Novel opportunities for therapeutic interventions into skin cancers

Skin cancers are by far the most frequently diagnosed human cancers. The closely related transcriptional co-regulator proteins YAP and TAZ (WWTR1) have emerged as important drivers of tumour initiation, progression and metastasis in melanoma and non-melanoma skin cancers. YAP/TAZ serve as an essential signalling hub by integrating signals from multiple upstream pathways. In this review, we summarize the roles of YAP/TAZ in skin physiology and tumorigenesis and discuss recent efforts of therapeutic interventions that target YAP/TAZ in in both preclinical and clinical settings, as well as their prospects for use as skin cancer treatments.

Recent insight into the role and therapeutic potential of YAP/TAZ in gastrointestinal cancers

With the rapid development of cancer treatment, gastrointestinal (GI) cancers are still the most prevalent malignancies with high morbidity and mortality worldwide. Dysregulation of the Hippo signaling pathway has been recognized to play a critical role during cancer development and adopted for monitoring disease progression and therapy response. Despite the well-documented tumor proliferation and metastasis, recent efforts in two core Hippo components, Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ), have identified as the driving forces behind cancer metabolism, stemness, tumor immunity, and therapy resistance. Understanding the molecular mechanisms by which YAP/TAZ facilitates the tumorigenesis and progression of GI cancer, and identifying novel therapeutic strategies for targeting YAP/TAZ are crucial to GI cancer treatment and prevention. In this study, we summarize the latest findings on the function and regulatory mechanisms of YAP/TAZ in GI cancers, and highlight the translational significance of targeting YAP/TAZ for cancer therapies.

Interplay Between Fatty Acids, Stearoyl-Co-A Desaturase, Mechanistic Target of Rapamycin, and Yes-Associated Protein/Transcriptional Coactivator With PDZ-Binding Motif in Promoting Hepatocellular Carcinoma

Nonalcoholic fatty liver disease has reached pandemic proportions with one of its most consequential complications being hepatocellular carcinoma (HCC). Nonalcoholic fatty liver disease-related HCC is becoming the leading indication for liver transplantation in the United States. Given the scarcity of available organs, early detection and prevention remain key in prevention and management of the disease. Over the years, the yes-associated protein (YAP)/transcriptional coactivator with PDZ-binding motif (TAZ) pathway emerged as a key signal transduction pathway in the pathogenesis of HCC. In this review, we explore the interplay between the YAP/TAZ pathway as a point of convergence in HCC pathogenesis. We review the evidence of how lipid reprogramming and key lipid pathways, saturated and monounsaturated fatty acids (through the rate-limiting enzyme stearoyl Co-A desaturase), the mevalonic acid pathway (the role of statins), and mechanistic target of rapamycin all play critical roles in intricate and complex networks that tightly regulate the YAP/TAZ pro-oncogenic pathway.

Statins Inhibit Inflammatory Cytokine Production by Macrophages and Acinar-to-Ductal Metaplasia of Pancreatic Cells

BACKGROUND AND AIMS

Animal data show that the presence of an oncogenic Kras mutation in pancreatic acinar cells leads to acinar-to-ductal metaplasia (ADM), pancreatic intraepithelial neoplasia (PanIN), and pancreatic ductal adenocarcinoma (PDAC). Inflammatory macrophages play an important role in the formation of ADMs and transition to PanINs. Epidemiologically, statins are associated with a reduced risk of PDAC. We investigated whether statins inhibit inflammatory cytokine production in macrophages and whether this leads to reduced ADM formation.

METHODS

The efficacy of statins on inflammatory cytokine production in 2 macrophage cell lines was measured by real-time polymerase chain reaction and enzyme-linked immunosorbent assay. The effect of macrophage-conditioned medium on ADM in primary pancreatic acinar cells was investigated. Mouse pancreatic tissue samples were analyzed for macrophage numbers, cytokine levels, and neoplastic/dysplastic area.

RESULTS

Lipophilic statins prevented inflammatory cytokine production in Raw264.7 and J774A.1 cells stimulated by lipopolysaccharide. The inhibitory effect of statins was mediated by inhibition of mevalonate and geranylgeranyl pyrophosphate synthesis and disruption of the actin cytoskeleton but not by a reduction in intracellular cholesterol. Treatment of macrophages with lipophilic statins also blocked ADM formation of primary pancreatic acinar cells. Furthermore, oral administration of simvastatin was associated with a reduction in the number of intrapancreatic macrophages, decreased inflammatory cytokine levels in the pancreas, and attenuated ADM/PanIN formation in mice.

CONCLUSION

Our data support the hypothesis that statins oppose early PDAC development by their effects on macrophages and ADM formation. The inhibitory actions of statins on macrophages may collaborate with direct inhibitory effects on transformed pancreatic epithelial cells, which cumulatively may reduce early PDAC development and progression.

Mechanical Cues, E-Cadherin Expression and Cell "Sociality" Are Crucial Crossroads in Determining Pancreatic Ductal Adenocarcinoma Cells Behavior

E-cadherin, an epithelial-to-mesenchymal transition (EMT) marker, is coupled to actin cytoskeleton and distributes cell forces acting on cells. Since YAP transduces mechanical signals involving actin cytoskeleton, we aimed to investigate the relationship between YAP and mechanical cues in pancreatic ductal adenocarcinoma (PDAC) cell lines, characterized by different EMT-related phenotypes, cultured in 2D monolayers and 3D spheroids. We observed that the YAP/p-YAP ratio was reduced in HPAC and MIA PaCa-2 cell lines and remained unchanged in BxPC-3 cells when cultured in a 3D setting. CTGF and CYR61 gene expression were down-regulated in all PDAC 3D compared to 2D cultures, without any significant effect following actin cytoskeleton inhibition by Cytochalasin B (CyB) treatment. Moreover, LATS1 mRNA, indicating the activation of the Hippo pathway, was not influenced by CyB and differed in all PDAC cell lines having different EMT-related phenotype but a similar pattern of CTGF and CYR61 expression. Although the role of YAP modulation in response to mechanical cues in cancer cells remains to be completely elucidated, our results suggest that cell arrangement and phenotype can determine variable outcomes to mechanical stimuli in PDAC cells. Moreover, it is possible to speculate that YAP and Hippo pathways may act as parallel and not exclusive inputs that, converging at some points, may impact cell behavior.

An overview of the crosstalk between YAP and cGAS-STING signaling in non-small cell lung cancer: it takes two to tango

The cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway is recognized as a main mediator bridging innate and adaptive immunity, recent advances have expanded its roles to anti-tumor immunity and carcinogenesis. Loss of cGAS-STING signaling in non-small cell lung cancer (NSCLC) leads to enhanced tumorigenicity and decreased cytotoxic T lymphocyte infiltration. Apart from its anticancer response, persistent overreaction of cGAS-STING signaling promotes progression of certain inflammation-aggravated cancers. Activation of the pro-inflammatory nucleic acid sensing pathway can trigger Hippo pathway, which mediates the inactivation of Yes-associated protein 1 (YAP1) and its paralogue transcriptional co-regulators with PDZ-binding motif (TAZ, also known as WWTR1), and subsequent suppression of tumorigenesis. Active YAP acts as a transcriptional driver in bolstering immunosuppressive cytokines to evade immune surveillance and promote occurrence of preneoplasia. It is reasonable that aggressive tumors co-opt these regulators to generate few immunogenic antigens and drive tumorigenic behaviors via a highly cooperative manner. Given their multifaced roles, we profile the molecular biology characteristic and current status underpinning oncogenic YAP, review its crosstalk roles with cGAS/STING pathway in NSCLC, and summarize the major clinical investigations in NSCLC with TCGA database.

The YAP/TAZ Signaling Pathway in the Tumor Microenvironment and Carcinogenesis: Current Knowledge and Therapeutic Promises

The yes-associated protein (YAP) and the transcriptional coactivator with PDZ-binding motif (TAZ) are transcriptional coactivators, members of the Hippo signaling pathway, which play a critical role in cell growth regulation, embryonic development, regeneration, proliferation, and cancer origin and progression. The mechanism involves the nuclear binding of the un-phosphorylated YAP/TAZ complex to release the transcriptional enhanced associate domain (TEAD) from its repressors. The active ternary complex is responsible for the aforementioned biological effects. Overexpression of YAP/TAZ has been reported in cancer stem cells and tumor resistance. The resistance involves chemotherapy, targeted therapy, and immunotherapy. This review provides an overview of YAP/TAZ pathways’ role in carcinogenesis and tumor microenvironment. Potential therapeutic alternatives are also discussed.

Statin use and incidence and mortality of breast and gynecology cancer: A cohort study using the National Health Insurance claims database

Previous studies have reported inconsistent findings concerning the impact of statin use on cancer prevention. This study examined the association between statin use and cancer incidence and mortality related to breast and gynecologic cancers in South Korea. A population-based cohort study was conducted using the National Health Insurance claims database. Women aged 45-70 years old who had taken statins for at least 6 months were compared to statin non-users of the same age from January 2005 to June 2013. The primary outcomes were cancer incidence and mortality related to breast cancer, total gynecologic cancers, cervix uteri cancer, and ovarian cancer. Cox proportional hazards regression was conducted to calculate the adjusted hazard ratios (aHRs) and 95% confidence intervals (95% CIs). Out of 587 705 women, there were 3591 cases of breast cancer, 2239 cases of gynecologic cancers, and 565 breast and total gynecologic cancer deaths during 7.6 person-years. The aHRs for the association between the risk of each cancer and statin use were 0.88 (95% CI 0.79-0.97) for breast cancer and 0.83 (95% CI 0.67-0.99) for cervix uteri cancer. Statin use was associated with decreased breast cancer mortality (HR = 0.65, 95% CI 0.43-0.99) and total gynecologic cancer mortality (HR = 0.70, 95% CI 0.50-0.98). A dose-response relationship was only found for all-cancer mortality. Statin use for at least 6 months was significantly associated with a lower risk of breast and cervix uteri cancer incidence, and with lower mortality of breast and gynecologic cancers. Further research on these associations will be needed. This article is protected by copyright. All rights reserved.

Crosstalk between KRAS, SRC and YAP Signaling in Pancreatic Cancer: Interactions Leading to Aggressive Disease and Drug Resistance

Pancreatic ductal adenocarcinoma (PDAC), the predominant form of pancreatic cancer, remains a devastating disease. The purpose of this review is to highlight recent literature on mechanistic and translational developments that advance our understanding of a complex crosstalk between KRAS, YAP and Src tyrosine kinase family (SFK) in PDAC development and maintenance. We discuss recent studies indicating the importance of RAS dimerization in signal transduction and new findings showing that the potent pro-oncogenic members of the SFK phosphorylate and inhibit RAS function. These surprising findings imply that RAS may not play a crucial role in maintaining certain subtypes of PDAC. In support of this interpretation, current evidence indicates that the survival of the basal-like subtype of PDAC is less dependent on RAS but relies, at least in part, on the activity of YAP/TAZ. Based on current evidence, we propose that SFK propels PDAC cells to a state of high metastasis, epithelial-mesenchymal transition (EMT) and reduced dependence on KRAS signaling, salient features of the aggressive basal-like/squamous subtype of PDAC. Strategies for PDAC treatment should consider the opposite effects of tyrosine phosphorylation on KRAS and SFK/YAP in the design of drug combinations that target these novel crosstalk mechanisms and overcome drug resistance.

MICAL2 Contributes to Gastric Cancer Cell Proliferation by Promoting YAP Dephosphorylation and Nuclear Translocation

Dynamic cytoskeletal rearrangements underlie the changes that occur during cell division in proliferating cells. MICAL2 has been reported to possess reactive oxygen species- (ROS-) generating properties and act as an important regulator of cytoskeletal dynamics. However, whether it plays a role in gastric cancer cell proliferation is not known. In the present study, we found that MICAL2 was highly expressed in gastric cancer tissues, and this high expression level was associated with carcinogenesis and poor overall survival in gastric cancer patients. The knockdown of MICAL2 led to cell cycle arrest in the S phase and attenuated cell proliferation. Concomitant with S-phase arrest, a decrease in CDK6 and cyclin D protein levels was observed. Furthermore, MICAL2 knockdown attenuated intracellular ROS generation, while MICAL2 overexpression led to a decrease in the p-YAP/YAP ratio and promoted YAP nuclear localization and cell proliferation, effects that were reversed by pretreatment with the ROS scavenger N-acetyl-L-cysteine (NAC) and SOD-mimetic drug tempol. We further found that MICAL2 induced Cdc42 activation, and activated Cdc42 mediated the effect of MICAL2 on YAP dephosphorylation and nuclear translocation. Collectively, our results showed that MICAL2 has a promotive effect on gastric cancer cell proliferation through ROS generation and Cdc42 activation, both of which independently contribute to YAP dephosphorylation and its nuclear translocation.

Drivers of Gene Expression Dysregulation in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) remains a devastating disease with a poor prognosis. The functional consequences of common genetic aberrations and their roles in treatment strategies have been extensively reviewed. In addition to these genomic aberrations, consideration of non-genetic drivers of altered oncogene expression is essential to account for the diversity in PDAC phenotypes. In this review we seek to assess our current understanding of mechanisms of gene expression dysregulation. We focus on four drivers of gene expression dysregulation, including mutations, transcription factors, epigenetic regulators, and RNA stability/isoform regulation, in the context of PDAC pathogenesis. Recent studies provide much-needed insight into the role of gene expression dysregulation in dissecting tumor heterogeneity and stratifying patients for the development of personalized treatment strategies.

Chemopreventive Agents After Pancreatic Resection for Ductal Adenocarcinoma: Legend or Scientific Evidence?

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is currently the fourth leading cause of cancer-related death in the USA. A wealth of evidence has demonstrated the chemopreventive activity of aspirin, statins, and metformin against PDAC. The aim of this study is to investigate the effect of aspirin, statins, and metformin on disease-free survival (DFS) and disease-specific survival (DSS) in a large population of PDAC patients undergoing pancreatic resection.

PATIENTS AND METHODS

All patients who underwent pancreatic resections between January 2015 and September 2018 were retrospectively reviewed. The potentially "chemopreventive agents" considered for the analysis were aspirin, statins, and metformin. Drug use was defined in case of regular assumption at least 6 months before diagnosis and regularly after surgery along the follow-up period.

RESULTS

A total of 430 patients were enrolled in this study, with median DFS and DSS of 21 months (IQR 13-30) months and 34 (IQR 26-52) months, respectively. On multivariable analysis, use of aspirin was associated with better DFS (HR: 0.62; p = 0.038). Metformin was associated with better DFS, without reaching statistical significance (p = 0.083). Use of statins did not influence DFS in the studied population. Aspirin, metformin, and statins were not associated with better DSS on multivariable analysis. Factors influencing DSS were pT3/pT4, N1, N2, no adjuvant treatment, G3, and ASA score > 3.

CONCLUSIONS

The results suggest that chronic use of aspirin is associated with increased DFS but not with better DSS after surgical resection in patients with PDAC.

Statin Type and Cancer Outcomes in Patients with Diabetes Type 2 and Solid Tumors

OBJECTIVE

Type 2 diabetes mellitus (T2DM) affects 10% of Americans and is associated with an increased incidence of cancer. Statins are first-line cholesterol-lowering medications in the treatment of hyperlipidemia. Several studies have demonstrated a relationship between statin use and reduced cancer incidence. We examined the cancer benefits of statin subtypes, with specific attention to disease-free survival (DFS) and overall survival (OS).

METHODS

This retrospective review included adults with T2DM diagnosed with solid tumors at Roswell Park Cancer Institute in Buffalo, NY, USA (2003-2010). Individuals with gestational diabetes, incomplete records, or diagnosed with rare solid tumors were excluded. Follow-up began at the date of diagnosis and ended with the first confirmed recurrence, death, or loss of contact. Demographics were assessed by Chi-square, Kaplan-Meier survival analyses, and Cox proportional hazards regression.

FINDINGS

Overall, 1102 patients met inclusion criteria, 52.1% of the study participants were female, and 578 participants (52.5%) died during the follow-up period which ranged from 0 to 156 months. Hydrophilic statin use was associated with improved DFS at 5-year follow-up (41.0% vs. 36.9%, P = 0.0077) compared to lipophilic statin use. Multivariate regression revealed that hydrophilic statins were associated with improved DFS (hazard ratio [HR]: 0.706, 95% confidence interval [CI]: 0.526-0.947) and OS (HR: 0.685, 95% CI: 0.503-0.934). Pravastatin was associated with improved OS (HR: 0.674, 95% CI: 0.471-0.964).

CONCLUSION

In patients with T2DM and cancer, hydrophilic statins, and pravastatin in particular, are associated with improved DFS as well as OS. Further research examining the cancer-specific effects of hydrophilic and lipophilic statins is needed to better understand their beneficial effects.

YAP in pancreatic cancer: oncogenic role and therapeutic strategy

Pancreatic cancer, especially pancreatic ductal adenocarcinoma (PDAC), remains a fatal disease with few efficacious treatments. The Hippo signaling pathway, an evolutionarily conserved signaling module, plays critical roles in tissue homeostasis, organ size control and tumorigenesis. The transcriptional coactivator yes-associated protein (YAP), a major downstream effector of the Hippo pathway, is associated with various human cancers including PDAC. Considering its importance in cancer, YAP is emerging as a promising therapeutic target. In this review, we summarize the current understanding of the oncogenic role and regulatory mechanism of YAP in PDAC, and the potential therapeutic strategies targeting YAP.

Regulation of Hippo signaling pathway in cancer: A MicroRNA perspective

Recent studies have suggested that Hippo signaling is not only involved in controlling organ size in Drosophila but can also regulate cell proliferation, tissue homeostasis, differentiation, apoptosis and regeneration. Any dysregulation of Hippo signaling, especially the hyper activation of its downstream effectors YAP/TAZ, can lead to uncontrolled cell proliferation and malignant transformation. In majority of cancers, expression of YAP/TAZ is extremely high and this increased expression of YAP/TAZ has been shown to be an independent predictor of prognosis and indicator of increased cell proliferation, metastasis and poor survival. In this review, we have summarized the most recent findings about the cross talk of Hippo signaling pathway with other signaling pathways and its regulation by different miRNAs in various cancer types. Recent evidence has suggested that Hippo pathway is also involved in mediating the resistance of different cancer cells to chemotherapeutic drugs and in a few cancer types, this is brought about by regulating miRNAs. Therefore, the delineation of the underlying mechanisms regulating the chemotherapeutic resistance might help in developing better treatment options. This review has attempted to provide an overview of different drugs/options which can be utilized to target oncogenic YAP/TAZ proteins for therapeutic interventions.

Pleiotropic use of Statins as non-lipid-lowering drugs

Statins, known as HMG-CoA reductase (HMGCR) inhibitors, have primarily been utilized for metabolic and angiographic medical applications because of their cholesterol-lowering effects. Similar to other drugs, statins may also induce a series of potential side effects. Statins inhibit the HMGCR (rate-limiting enzyme) activity in early stages of mevalonate pathway and then indirectly affect a number of intermediate products, including non-sterol isoprenoids (coenzyme Q10, dolichol etc.), which can result in impaired functions of body organs. Recently, scores of studies have uncovered additional functional mechanisms of statins in other diseases, such as diabetes mellitus, nervous system diseases, coronary heart disease, inflammation and cancers. This review aims to summarize the positive and adverse mechanisms of statin therapy. Statin care should be taken in the treatment of many diseases including cancers. Since the underlying mechanisms are not fully elucidated, future studies should spend more time and efforts on basic research to explore the mechanisms of statins.

Screening for YAP Inhibitors Identifies Statins as Modulators of Fibrosis

Idiopathic pulmonary fibrosis is a lung disease with limited therapeutic options that is characterized by pathological fibroblast activation and aberrant lung remodeling with scar formation. YAP (Yes-associated protein) is a transcriptional coactivator that mediates mechanical and biochemical signals controlling fibroblast activation. In this study, we developed a high-throughput small-molecule screen for YAP inhibitors in primary human lung fibroblasts. Multiple HMG-CoA (hydroxymethylglutaryl-coenzyme A) reductase inhibitors (statins) were found to inhibit YAP nuclear localization via induction of YAP phosphorylation, cytoplasmic retention, and degradation. We further show that the mevalonate pathway regulates YAP activation, and that simvastatin treatment reduces fibrosis markers in activated human lung fibroblasts and in the bleomycin mouse model of pulmonary fibrosis. Finally, we show that simvastatin modulates YAP in vivo in mouse lung fibroblasts. Our results highlight the potential of small-molecule screens for YAP inhibitors and provide a mechanism for the antifibrotic activity of statins in idiopathic pulmonary fibrosis.

The YAP/TAZ Pathway in Osteogenesis and Bone Sarcoma Pathogenesis

YAP and TAZ are intracellular messengers communicating multiple interacting extracellular biophysical and biochemical cues to the transcription apparatus in the nucleus and back to the cell/tissue microenvironment interface through the regulation of cytoskeletal and extracellular matrix components. Their activity is negatively and positively controlled by multiple phosphorylation events. Phenotypically, they serve an important role in cellular plasticity and lineage determination during development. As they regulate self-renewal, proliferation, migration, invasion and differentiation of stem cells, perturbed expression of YAP/TAZ signaling components play important roles in tumorigenesis and metastasis. Despite their high structural similarity, YAP and TAZ are functionally not identical and may play distinct cell type and differentiation stage-specific roles mediated by a diversity of downstream effectors and upstream regulatory molecules. However, YAP and TAZ are frequently looked at as functionally redundant and are not sufficiently discriminated in the scientific literature. As the extracellular matrix composition and mechanosignaling are of particular relevance in bone formation during embryogenesis, post-natal bone elongation and bone regeneration, YAP/TAZ are believed to have critical functions in these processes. Depending on the differentiation stage of mesenchymal stem cells during endochondral bone development, YAP and TAZ serve distinct roles, which are also reflected in bone tumors arising from the mesenchymal lineage at different developmental stages. Efforts to clinically translate the wealth of available knowledge of the pathway for cancer diagnostic and therapeutic purposes focus mainly on YAP and TAZ expression and their role as transcriptional co-activators of TEAD transcription factors but rarely consider the expression and activity of pathway modulatory components and other transcriptional partners of YAP and TAZ. As there is a growing body of evidence for YAP and TAZ as potential therapeutic targets in several cancers, we here interrogate the applicability of this concept to bone tumors. To this end, this review aims to summarize our current knowledge of YAP and TAZ in cell plasticity, normal bone development and bone cancer.

SRPX2 Promotes Cell Proliferation and Invasion in Osteosarcoma Through Regulating Hippo Signaling Pathway

Background/Purpose

Osteosarcoma (OS), a primary bone malignancy, is characterized by a high rate of metastasis. It has been found that Sushi repeat containing protein X-linked 2 (SRPX2) is involved in tumor cell proliferation, adhesion, invasion and migration. The current work aimed to explore the effect of SRPX2 on OS cell invasion and proliferation.

Methods

Immunohistochemistry (IHC), Western blotting and reverse transcription-polymerase chain reaction (RT-PCR) were used to detect the expression of the associated protein in OS tissues and cell lines. Cell counting kit-8 (CCK8), transwell and colony formation assays were used to determine cell viability, invasion, and proliferation, respectively. The in vivo tumorigenic ability of SRPX2 gene was determined using nude mouse tumorigenesis test.

Results

SRPX2 knockdown suppressed the viability, while SRPX2 overexpression increased the invasion and colony formation ability of the cells in vitro. In vivo experiments demonstrated that SRPX2 knockdown inhibited tumor growth and invasion as evidenced by decreased Ki67 and N-cadherin levels, and increased E-cadherin level. Downregulation of SRPX2 increased YAP phosphorylation resulting in reduced nuclear translocation to activate Hippo signaling pathway. The promotion of cell viability, colony-forming ability, and invasion, and the inhibition of CTGF, Cyr61, and Birc5 levels promoted by SRPX2 overexpression were reversed by YAP inhibition.

Conclusion

SRPX2 increased cell proliferation and invasion in osteosarcoma by activating Hippo signaling pathway.

Obesity-Induced Adipose Tissue Inflammation as a Strong Promotional Factor for Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is expected to soon become the second leading cause of cancer related deaths in the United States. This may be due to the rising obesity prevalence, which is a recognized risk factor for PDAC. There is great interest in deciphering the underlying driving mechanisms of the obesity–PDAC link. Visceral adiposity has a strong correlation to certain metabolic diseases and gastrointestinal cancers, including PDAC. In fact, our own data strongly suggest that visceral adipose tissue inflammation is a strong promoter for PDAC growth and progression in a genetically engineered mouse model of PDAC and diet-induced obesity. In this review, we will discuss the relationship between obesity-associated adipose tissue inflammation and PDAC development, with a focus on the key molecular and cellular components in the dysfunctional visceral adipose tissue, which provides a tumor permissive environment.

[Nucleus translocation of membrane/cytoplasm proteins in tumor cells]

Proteins are the physical basis of life and perform all kinds of life activities. Proteins have different orientations and function in different tissues. The same protein, located in different subcellular regions, can perform different and even opposite functions. Both functional and structural proteins are capable of undergoing re-localization which can directly or indirectly participate in signal transduction. Due to abnormal transduction of signals during carcinogenesis, the proteins originally expressed in the cytoplasm are translocated into the nucleus and lead to functional changes in the tumor tissue. The changes of protein localization are affected by many factors, including the interaction between proteins, expression level of proteins and the cleaved intracellular domain of transmembrane protein.