Arousal of cancer-associated stroma: overexpression of palladin activates fibroblasts to promote tumor invasion

Targeting ROCK2 improves macromolecular permeability in a 3D fibrotic pancreatic cancer microenvironment model

Pancreatic cancer is characterized by a densely fibrotic stroma. The fibrotic stroma hinders the intratumoral penetration of nanomedicine and diminishes therapeutic efficacy. Fibrosis is characterized by an abnormal organization of extracellular matrix (ECM) components, namely the abnormal deposition and/or orientation of collagen and fibronectin. Abnormal ECM organization is chiefly driven by pathological signaling in pancreatic stellate cells (PSCs), the main cell type involved in fibrogenesis. However, whether targeting signaling pathways involved in abnormal ECM organization improves the intratumoral penetration of nanomedicines is unknown. Here, we show that targeting transforming growth factor-β (TGFβ)/Rho-associated kinase (ROCK) 1/2 signaling in PSCs normalizes ECM organization and concomitantly improves macromolecular permeability of the fibrotic stroma. Using a 3-dimensional cell culture model of the fibrotic pancreatic cancer microenvironment, we found that pharmacological inhibition of TGFβ or ROCK1/2 improves the permeation of various macromolecules. By using an isoform-specific pharmacological inhibitor and siRNAs, we show that targeting ROCK2, but not ROCK1, alone is sufficient to normalize ECM organization and improve macromolecular permeability. Moreover, we found that ROCK2 inhibition/knockdown attenuates Yes-associated protein (YAP) nuclear localization in fibroblasts co-cultured with pancreatic cancer cells in 3D. Finally, pharmacological inhibition or siRNA-mediated knockdown of YAP normalized ECM organization and improved macromolecular permeability. Our results together suggest that the TGFβ/ROCK2/YAP signaling axis may be therapeutically targeted to normalize ECM organization and improve macromolecular permeability to augment therapeutic efficacy of nanomedicines in pancreatic cancer.

Multifaceted TGF-β signaling, a master regulator: From bench-to-bedside, intricacies, and complexities

Physiological embryogenesis and adult tissue homeostasis are regulated by transforming growth factor-β (TGF-β), an evolutionarily conserved family of secreted polypeptide factors, acting in an autocrine and paracrine manner. The role of TGF-β in inflammation, fibrosis, and cancer is complex and sometimes even contradictory, exhibiting either inhibitory or promoting effects depending on the stage of the disease. Under pathological conditions, especially fibrosis and cancer, overexpressed TGF-β causes extracellular matrix deposition, epithelial-mesenchymal transition, cancer-associated fibroblast formation, and/or angiogenesis. In this review article, we have tried to dive deep into the mechanism of action of TGF-β in inflammation, fibrosis, and carcinogenesis. As TGF-β and its downstream signaling mechanism are implicated in fibrosis and carcinogenesis blocking this signaling mechanism appears to be a promising avenue. However, targeting TGF-β carries substantial risk as this pathway is implicated in multiple homeostatic processes and is also known to have tumor-suppressor functions. There is a need for careful dosing of TGF-β drugs for therapeutic use and patient selection.

Hypoxia induces immunosuppression, metastasis and drug resistance in pancreatic cancers

Pancreatic cancer is one of the common malignant tumors of the digestive system and is known as the "king of cancers". It is extremely difficult to diagnose at an early stage, the disease progresses rapidly, and the effect of chemotherapy and radiotherapy is poor, so the prognosis of pancreatic cancer patients is very poor. Numerous studies have suggested that hypoxia is closely related to the development and progression of pancreatic cancer. Inadequate blood supply and desmoplasia in the microenvironment of pancreatic cancer can result in its extreme hypoxia. This hypoxic microenvironment can further contribute to angiogenesis and desmoplasia. Hypoxia is mediated by the complex hypoxia inducible factor (HIF) signaling pathway and plays an important role in the formation of a highly immunosuppressive microenvironment and the metastasis of pancreatic cancer. Further work on the hypoxic microenvironment will help clarify the specific mechanisms of the role of hypoxia in pancreatic cancer and provide a basis for the realization of hypoxia-targeted therapeutic and diagnostic strategies.

The Cell Biology of Metastatic Invasion in Pancreatic Cancer: Updates and Mechanistic Insights

Pancreatic ductal adenocarcinoma (PDAC) is one of the leading causes of cancer-related mortality worldwide. This is largely due to the lack of routine screening protocols, an absence of symptoms in early-stage disease leading to late detection, and a paucity of effective treatment options. Critically, the majority of patients either present with metastatic disease or rapidly develop metastatic disease. Thus, there is an urgent need to deepen our understanding of metastasis in PDAC. During metastasis, tumor cells escape from the primary tumor, enter the circulation, and travel to a distant site to form a secondary tumor. In order to accomplish this relatively rare event, tumor cells develop an enhanced ability to detach from the primary tumor, migrate into the surrounding matrix, and invade across the basement membrane. In addition, cancer cells interact with the various cell types and matrix proteins that comprise the tumor microenvironment, with some of these factors working to promote metastasis and others working to suppress it. In PDAC, many of these processes are not well understood. The purpose of this review is to highlight recent advances in the cell biology of the early steps of the metastatic cascade in pancreatic cancer. Specifically, we will examine the regulation of epithelial-to-mesenchymal transition (EMT) in PDAC and its requirement for metastasis, summarize our understanding of how PDAC cells invade and degrade the surrounding matrix, and discuss how migration and adhesion dynamics are regulated in PDAC to optimize cancer cell motility. In addition, the role of the tumor microenvironment in PDAC will also be discussed for each of these invasive processes.

Construction of a radiogenomic association map of pancreatic ductal adenocarcinoma

BACKGROUND

Pancreatic adenocarcinoma (PDAC) persists as a malignancy with high morbidity and mortality that can benefit from new means to characterize and detect these tumors, such as radiogenomics. In order to address this gap in the literature, constructed a transcriptomic-CT radiogenomic (RG) map for PDAC.

METHODS

In this Institutional Review Board approved study, a cohort of subjects (n = 50) with gene expression profile data paired with histopathologically confirmed resectable or borderline resectable PDAC were identified. Studies with pre-operative contrast-enhanced CT images were independently assessed for a set of 88 predefined imaging features. Microarray gene expression profiling was then carried out on the histopathologically confirmed pancreatic adenocarcinomas and gene networks were constructed using Weighted Gene Correlation Network Analysis (WCGNA) (n = 37). Data were analyzed with bioinformatics analyses, multivariate regression-based methods, and Kaplan-Meier survival analyses.

RESULTS

Survival analyses identified multiple features of interest that were significantly associated with overall survival, including Tumor Height (P = 0.014), Tumor Contour (P = 0.033), Tumor-stroma Interface (P = 0.014), and the Tumor Enhancement Ratio (P = 0.047). Gene networks for these imaging features were then constructed using WCGNA and further annotated according to the Gene Ontology (GO) annotation framework for a biologically coherent interpretation of the imaging trait-associated gene networks, ultimately resulting in a PDAC RG CT-transcriptome map composed of 3 stage-independent imaging traits enriched in metabolic processes, telomerase activity, and podosome assembly (P < 0.05).

CONCLUSIONS

A CT-transcriptomic RG map for PDAC composed of semantic and quantitative traits with associated biology processes predictive of overall survival, was constructed, that serves as a reference for further mechanistic studies for non-invasive phenotyping of pancreatic tumors.

Palladin promotes cancer stem cell-like properties in lung cancer by activating Wnt/Β-Catenin signaling

BACKGROUND

Cancer stem cells (CSCs) are responsible for drug resistance, cancer relapse, and metastasis. Here, we report the first analysis of Palladin expression and its impacts on stem cell-like properties in lung cancer.

METHODS

Tissue microarrays were used to investigate Palladin expression and its association with prognosis. Immunofluorescence (IF), flow fluorescence assay, and Western blot were performed to detect Palladin expression in 6 NSCLC cell lines. Cell phenotypes and drug resistance were evaluated. Xenograft models were constructed to confirm the role of Palladin in vivo.

RESULTS

By using the tissue microarrays, Palladin was identified to be highly expressed in the cytoplasm, specifically in the cytomembrane of NSCLC, and its high expression is associated with poor prognosis. Palladin is widely expressed and enriched in the sphere cells. The in vitro and in vivo studies showed that Palladin promoted stem cell-like properties, including cell viability, invasion, migration, self-renewal abilities, taxol resistance, and tumorigenicity. Western blot revealed that Palladin promoted the accumulation of β-catenin and activated Wnt/β-catenin signaling. Tissue microarrays analysis further confirmed the positive correlation between Palladin and β-catenin. Wnt/β-catenin pathway inhibitor blocked the Palladin-induced enhancement of sphere-forming.

CONCLUSIONS

Palladin might act as an oncogene by promoting CSCs-like properties and tumorigenicity of NSCLC cells via the Wnt/β-catenin signaling pathway. Besides, Palladin was identified to have the potential as a cell surface marker for LCSCs identification. These findings provide a possible target for developing putative agents targeted to LCSCs.

Cancer-associated fibroblasts and the tumor microenvironment in non-small cell lung cancer

INTRODUCTION

Non-small cell lung cancer (NSCLC) has a markedly poor prognosis as it progresses, and the prognosis is still unsatisfactory even with modern treatments. Cancer is composed of not only cancer cells, but also stroma consisting of various cell types. Cancer-associated fibroblasts (CAFs) are a major component of the stroma and the associated tumor microenvironment (TME). Particularly, CAFs are a critical component in elucidating the biological mechanisms of cancer progression and new therapeutic targets. This article outlines the TME formed by CAFs in NSCLC.

AREAS COVERED

Focusing on the TME in NSCLC, we discuss the mechanisms by which CAFs are involved in cancer progression, drug resistance, and the development of therapies targeting CAFs.

EXPERT OPINION

In the TME, CAFs profoundly contribute to tumor progression by interacting with cancer cells through direct contact or paracrine cytokine signaling. CAFs also interact with various other stromal components to establish a tumor-promoting immunosuppressive microenvironment and remodel the extracellular matrix. Furthermore, these effects are closely associated with drug resistance. Further elucidation of the stromal microenvironment, including CAFs, could prove to be crucial in the treatment of NSCLC.

Palladin isoforms 3 and 4 regulate cancer-associated fibroblast pro-tumor functions in pancreatic ductal adenocarcinoma

Pancreatic Ductal Adenocarcinoma (PDAC) has a five-year survival under 10%. Treatment is compromised due to a fibrotic-like stromal remodeling process, known as desmoplasia, which limits therapeutic perfusion, supports tumor progression, and establishes an immunosuppressive microenvironment. These processes are driven by cancer-associated fibroblasts (CAFs), functionally activated through transforming growth factor beta1 (TGFβ1). CAFs produce a topographically aligned extracellular matrix (ECM) that correlates with reduced overall survival. Paradoxically, ablation of CAF populations results in a more aggressive disease, suggesting CAFs can also restrain PDAC progression. Thus, unraveling the mechanism(s) underlying CAF functions could lead to therapies that reinstate the tumor-suppressive features of the pancreatic stroma. CAF activation involves the f-actin organizing protein palladin. CAFs express two palladin isoforms (iso3 and iso4) which are up-regulated in response to TGFβ1. However, the roles of iso3 and iso4 in CAF functions remain elusive. Using a CAF-derived ECM model, we uncovered that iso3/iso4 are required to sustain TGFβ1-dependent CAF activation, secrete immunosuppressive cytokines, and produce a pro-tumoral ECM. Findings demonstrate a novel role for CAF palladin and suggest that iso3/iso4 regulate both redundant and specific tumor-supportive desmoplastic functions. This study highlights the therapeutic potential of targeting CAFs to restore fibroblastic anti-tumor activity in the pancreatic microenvironment.

The Adhesome Network: Key Components Shaping the Tumour Stroma

Beyond the conventional perception of solid tumours as mere masses of cancer cells, advanced cancer research focuses on the complex contributions of tumour-associated host cells that are known as "tumour microenvironment" (TME). It has been long appreciated that the tumour stroma, composed mainly of blood vessels, cancer-associated fibroblasts and immune cells, together with the extracellular matrix (ECM), define the tumour architecture and influence cancer cell properties. Besides soluble cues, that mediate the crosstalk between tumour and stroma cells, cell adhesion to ECM arises as a crucial determinant in cancer progression. In this review, we discuss how adhesome, the intracellular protein network formed at cell adhesions, regulate the TME and control malignancy. The role of adhesome extends beyond the physical attachment of cells to ECM and the regulation of cytoskeletal remodelling and acts as a signalling and mechanosensing hub, orchestrating cellular responses that shape the tumour milieu.

Tumor Cellular and Microenvironmental Cues Controlling Invadopodia Formation

During the metastatic progression, invading cells might achieve degradation and subsequent invasion into the extracellular matrix (ECM) and the underlying vasculature using invadopodia, F-actin-based and force-supporting protrusive membrane structures, operating focalized proteolysis. Their formation is a dynamic process requiring the combined and synergistic activity of ECM-modifying proteins with cellular receptors, and the interplay with factors from the tumor microenvironment (TME). Significant advances have been made in understanding how invadopodia are assembled and how they progress in degradative protrusions, as well as their disassembly, and the cooperation between cellular signals and ECM conditions governing invadopodia formation and activity, holding promise to translation into the identification of molecular targets for therapeutic interventions. These findings have revealed the existence of biochemical and mechanical interactions not only between the actin cores of invadopodia and specific intracellular structures, including the cell nucleus, the microtubular network, and vesicular trafficking players, but also with elements of the TME, such as stromal cells, ECM components, mechanical forces, and metabolic conditions. These interactions reflect the complexity and intricate regulation of invadopodia and suggest that many aspects of their formation and function remain to be determined. In this review, we will provide a brief description of invadopodia and tackle the most recent findings on their regulation by cellular signaling as well as by inputs from the TME. The identification and interplay between these inputs will offer a deeper mechanistic understanding of cell invasion during the metastatic process and will help the development of more effective therapeutic strategies.

Proteome alterations in pancreatic ductal adenocarcinoma

Proteins are the essential functional biomolecules profoundly implicated in all aspects of pancreatic tumorigenesis and its progression. While common genomic factors, such as KRAS, TP53, SMAD4, and CDKN2A have been well recognized in association of pancreatic ductal adenocarcinoma (PDAC), our understanding of functional changes at the proteome level merits further investigation. Malignance associated proteome alterations can be attributed to the convoluted outcomes from genetic, epigenetic and environmental factors in initiating and progressing PDAC, and may reflect on changes in protein expressional level, structure, localization, as well as post-translational modifications (PTMs) status. The study of localized or systemic proteome alterations in PDAC, as well as its precursor lesions, such as pancreatic intraepithelial neoplasia (PanIN) and mucinous pancreatic cystic neoplasm, would provide unique perspectives in elucidating functional molecular events underlying PDAC. While efforts have been made, challenges still exist to comprehensively integrate much of the proteomic discovery to the perspectives gained from genomic studies in the context of biomarker discovery. Novel approaches and data from well-defined longitudinal clinical studies and experimental models are needed to facilitate the study of PDAC and precursor lesions for early detection and intervention.

Change in distribution of cytoskeleton-associated proteins, lasp-1 and palladin, during uterine receptivity in the rat endometrium

The epithelium of the uterine lumen is the first point of contact with the blastocyst before implantation. To facilitate pregnancy, these uterine epithelial cells (UECs) undergo morphological changes specific to the receptive uterus. These changes include basal, lateral and apical alterations in the plasma membrane of UECs. This study looked at the cytoskeletal and focal adhesion-associated proteins, lasp-1 and palladin, in the uterus during early pregnancy in the rat. Two palladin isoforms, 140 kDa and 90 kDa, were analysed, with the migration-associated 140-kDa isoform increasing significantly at the time of implantation when compared with the time of fertilisation. Lasp-1 was similarly increased at this time, whilst also being located predominantly apically and laterally in the UECs, suggesting a role in the initial contact between the UECs and the blastocyst. This is the first study to investigate palladin and lasp-1 in the uterine luminal epithelium and suggests an importance for these cytoskeletal proteins in the morphological changes the UECs undergo for pregnancy to occur.

Diagnostic utility of epigenetics in breast cancer - A review

Epigenetic alterations are clearly involved in cancer initiation and progression as recent epigenetic studies of genomic DNA, histone modifications and micro-RNA alterations suggest that these are playing an important role in the incidence of breast cancer. Epigenetic information has recently gained the attention of researchers because epigenetic modification of the genome in breast cancer is still an evolving area for researchers. Several active compounds present in foods, poisons, drugs, and industrial chemicals may as a result of epigenetic mechanisms increase or decrease the risk of breast cancer. Epigenetic regulation is critical in normal growth and development and closely conditions the transcriptional potential of genes. Epigenetic mechanisms convey genomic adaption to an environment thereby ultimately contributing towards given phenotype. In addition to the use of epigenetic alterations as a means of screening, epigenetic alterations in a tumor or adjacent tissues or peripheral blood may also help clinicians in determining prognosis and treatment of breast cancer. As we understand specific epigenetic alterations contributing to breast tumorigenesis and prognosis, these discoveries will lead to significant advances for breast cancer treatment, like in therapeutics that target methylation and histone modifications in breast cancer and the newer versions of the drugs are likely to play an important role in future clinical treatment.

The impact of cancer-associated fibroblasts on major hallmarks of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) constitutes one of the most challenging lethal tumors and has a very poor prognosis. In addition to cancer cells, the tumor microenvironment created by a repertoire of resident and recruited cells and the extracellular matrix also contribute to the acquisition of hallmarks of cancer. Among these factors, cancer-associated fibroblasts (CAFs) are critical components of the tumor microenvironment. CAFs originate from the activation of resident fibroblasts and pancreatic stellate cells, the differentiation of bone marrow-derived mesenchymal stem cells and epithelial-to-mesenchymal transition. CAFs acquire an activated phenotype via various cytokines and promote tumor proliferation and growth, accelerate invasion and metastasis, induce angiogenesis, promote inflammation and immune destruction, regulate tumor metabolism, and induce chemoresistance; these factors contribute to the acquisition of major hallmarks of PDAC. Therefore, an improved understanding of the impact of CAFs on the major hallmarks of PDAC will highlight the diagnostic and therapeutic values of these targeted cells.

Suppression of TGFβ-mediated conversion of endothelial cells and fibroblasts into cancer associated (myo)fibroblasts via HDAC inhibition

Background

Cancer-associated fibroblasts (CAFs) support tumour progression and invasion, and they secrete abundant extracellular matrix (ECM) that may shield tumour cells from immune checkpoint or kinase inhibitors. Targeting CAFs using drugs that revert their differentiation, or inhibit their tumour-supportive functions, has been considered as an anti-cancer strategy.

Methods

We have used human and murine cell culture models, atomic force microscopy (AFM), microarray analyses, CAF/tumour cell spheroid co-cultures and transgenic fibroblast reporter mice to study how targeting HDACs using small molecule inhibitors or siRNAs re-directs CAF differentiation and function in vitro and in vivo.

Results

From a small molecule screen, we identified Scriptaid, a selective inhibitor of HDACs 1/3/8, as a repressor of TGFβ-mediated CAF differentiation. Scriptaid inhibits ECM secretion, reduces cellular contraction and stiffness, and impairs collective cell invasion in CAF/tumour cell spheroid co-cultures. Scriptaid also reduces CAF abundance and delays tumour growth in vivo.

Conclusions

Scriptaid is a well-tolerated and effective HDACi that reverses many of the functional and phenotypic properties of CAFs. Impeding or reversing CAF activation/function by altering the cellular epigenetic regulatory machinery could control tumour growth and invasion, and be beneficial in combination with additional therapies that target cancer cells or immune cells directly.

Nectin-1 expression in cancer-associated fibroblasts is a predictor of poor prognosis for pancreatic ductal adenocarcinoma

PURPOSE

Nectin-1 is a cell adhesion molecule that regulates the formation of adherens junctions and tight junctions. We measured the expression of nectin-1 in cancer-associated fibroblasts (CAFs) in patients with pancreatic ductal adenocarcinoma (PDAC).

METHODS

Nectin-1 expression was measured via immunohistochemistry using tissue microarray blocks constructed from resected PDAC tissue from 258 patients. We screened for associations between nectin-1 expression and clinicopathological parameters. According to the percentage of CAFs stained, expression was classified as negative at ≤ 30% and positive at > 30%.

RESULTS

Nectin-1 expression was confirmed in CAFs from 64 patients (24.8%), and was associated with lymph node metastasis (p = 0.016), advanced Union for International Cancer Control stage (p = 0.016), perineural invasion (p = 0.022), pancreatic head tumors (p = 0.023), and shorter overall survival (p = 0.003). Multivariate analysis revealed that nectin-1 expression in CAFs was an independent prognostic factor (p = 0.038).

CONCLUSIONS

Diffuse nectin-1 expression in the CAFs of PDAC patients is associated with invasion, metastasis, and shorter survival.

Drug targeting to myofibroblasts: Implications for fibrosis and cancer

Myofibroblasts are the key players in extracellular matrix remodeling, a core phenomenon in numerous devastating fibrotic diseases. Not only in organ fibrosis, but also the pivotal role of myofibroblasts in tumor progression, invasion and metastasis has recently been highlighted. Myofibroblast targeting has gained tremendous attention in order to inhibit the progression of incurable fibrotic diseases, or to limit the myofibroblast-induced tumor progression and metastasis. In this review, we outline the origin of myofibroblasts, their general characteristics and functions during fibrosis progression in three major organs: liver, kidneys and lungs as well as in cancer. We will then discuss the state-of-the art drug targeting technologies to myofibroblasts in context of the above-mentioned organs and tumor microenvironment. The overall objective of this review is therefore to advance our understanding in drug targeting to myofibroblasts, and concurrently identify opportunities and challenges for designing new strategies to develop novel diagnostics and therapeutics against fibrosis and cancer.

Histone deacetylase inhibitors provoke a tumor supportive phenotype in pancreatic cancer associated fibroblasts

Although histone deacetylase inhibitors (HDACi) are a promising class of anti-cancer drugs, thus far, they have been unsuccessful in early phase clinical trials for pancreatic ductal adenocarcinoma (PDAC). One potential reason for their poor efficacy is the tumor stroma, where cancer-associated fibroblasts (CAFs) are a prominent cell type and a source of resistance to cancer therapies. Here, we demonstrate that stromal fibroblasts contribute to the poor efficacy of HDACi's in PDAC. HDACi-treated fibroblasts show increased biological aggressiveness and are characterized by increased secretion of pro-inflammatory tumor-supportive cytokines and chemokines. We find that HDAC2 binds to the enhancer and promoter regions of pro-inflammatory genes specifically in CAFs and in silico analysis identified AP-1 to be the most frequently associated transcription factor bound in these regions. Pharmacologic inhibition of pathways upstream of AP-1 suppresses the HDACi-induced inflammatory gene expression and tumor-supportive responses in fibroblasts. Our findings demonstrate that the combination of HDACi's with chemical inhibitors of the AP-1 signaling pathway attenuate the inflammatory phenotype of fibroblasts and may improve the efficacy of HDACi in PDAC and, potentially, in other solid tumors rich in stroma.

Human pancreatic stellate cells modulate 3D collagen alignment to promote the migration of pancreatic ductal adenocarcinoma cells

A hallmark of pancreatic ductal adenocarcinoma (PDAC) is the ability for cancer cells to aggressively infiltrate and navigate through a dense stroma during the metastatic process. Key features of the PDAC stroma include an abundant population of activated pancreatic stellate cells (PSCs) and highly aligned collagen fibers; however, important questions remain regarding how collagen becomes aligned and what the biological manifestations are. To better understand how PSCs, aligned collagen, and PDAC cells might cooperate during the transition to invasion, we utilized a microchannel-based in vitro tumor model and advanced imaging technologies to recreate and examine in vivo-like heterotypic interactions. We found that PSCs participate in a collaborative process with cancer cells by orchestrating the alignment of collagen fibers that, in turn, are permissive to enhanced cell migration. Additionally, direct contact between PSCs, collagen, and PDAC cells is critical to invasion and co-migration of both cell types. This suggests PSCs may accompany and assist in navigating PDAC cells through the stromal terrain. Together, our data provides a new role for PSCs in stimulating the metastatic process and underscores the importance of collagen alignment in cancer progression.

Disrupting glutamine metabolic pathways to sensitize gemcitabine-resistant pancreatic cancer

Pancreatic cancer is a lethal disease with poor prognosis. Gemcitabine has been the first line systemic treatment for pancreatic cancer. However, the rapid development of drug resistance has been a major hurdle in gemcitabine therapy leading to unsatisfactory patient outcomes. With the recent renewed understanding of glutamine metabolism involvement in drug resistance and immuno-response, we investigated the anti-tumor effect of a glutamine analog (6-diazo-5-oxo-L-norleucine) as an adjuvant treatment to sensitize chemoresistant pancreatic cancer cells. We demonstrate that disruption of glutamine metabolic pathways improves the efficacy of gemcitabine treatment. Such a disruption induces a cascade of events which impacts glycan biosynthesis through Hexosamine Biosynthesis Pathway (HBP), as well as cellular redox homeostasis, resulting in global changes in protein glycosylation, expression and functional effects. The proteome alterations induced in the resistant cancer cells and the secreted exosomes are intricately associated with the reduction in cell proliferation and the enhancement of cancer cell chemosensitivity. Proteins associated with EGFR signaling, including downstream AKT-mTOR pathways, MAPK pathway, as well as redox enzymes were downregulated in response to disruption of glutamine metabolic pathways.

Cancer-associated fibroblasts modulate growth factor signaling and extracellular matrix remodeling to regulate tumor metastasis

Cancer-associated fibroblasts (CAFs) are major components of the surrounding stroma of carcinomas that emerge in the tumor microenvironment as a result of signals derived from the cancer cells. Biochemical cross-talk between cancer cells and CAFs as well as mechanical remodeling of the stromal extracellular matrix (ECM) by CAFs are important contributors to tumor cell migration and invasion, which are critical for cancer progression from a primary tumor to metastatic disease. In this review, we discuss key paracrine signaling pathways between CAFs and cancer cells that promote cancer cell migration and invasion. In addition, we discuss physical changes that CAFs exert on the stromal ECM to facilitate migration and invasion of cancer cells.

The Role of Fibroblasts in Pancreatic Cancer: Extracellular Matrix Versus Paracrine Factors

BACKGROUND AND AIM: Desmoplasia is a characteristic feature and a suspected mechanism of tumor progression in pancreatic ductal adenocarcinoma (PDAC). Main constituents of the stroma involve cancer-associated fibroblasts (CAFs) and extracellular matrix (ECM). The aim of this study was to dissect the interaction of CAFs, ECM, and PDAC cells in both an in vitro setting and a large-scale clinical cohort study. METHODS AND MATERIAL: Patients operated for PDAC were identified from our prospectively maintained clinical database. A standard pathology protocol was applied for pancreatoduodenectomy specimens also assessing CAF activation as either CAF grade 0 or CAF grade +. Interaction between a spectrum of pancreatic cancer cell lines (PCCs) and mouse embryonic fibroblasts (NIH 3T3) was assessed in a conditioned medium experimental setup. RESULTS: One hundred eleven patients operated for PDAC from 2001 to 2011 were identified. Univariate analysis disclosed CAF grade + (P = .030), positive M status (P < .001), and lymph node ratio (LNR) > 0.1 (P = .045) to impair overall survival. Independent prognostic factors were CAF grade (P = .050) and positive M status (P = .002). CAF grade correlated with N status (CC = 0.206, P = .030), LNR (CC = 0.187, P = .049), tumor size (CC = −0.275, P = .003), and M status (CC = 0.190, P = .045). In the in vitro setting, paracrine effects of pancreatic cancer cell resulted in morphological activation of fibroblasts and tumor cell differentiation–dependent increase of fibroblast growth. Paracrine effects of poorly differentiated PCCs led to an upregulation of Vimentin in NIH 3T3 fibroblasts. Paracrine effects of fibroblasts on their part promoted cancer cell motility in all PCCs. As the second stromal component, fibroblast-derived ECM resulted in significantly decreased proliferation depending on density and led to upregulation of ZEB1 in poorly differentiated PCCs. CONCLUSION: In PDAC patients, positive CAF grading was identified as a negative prognostic parameter correlating with positive N status, high LNR, positive M status, and smaller tumor size. Whereas bilateral interaction of PCCs and CAFs promotes tumor progression, ECM poses PCC growth restrictions. In summary, our study discloses differential effects of stromal components and may help to interpret heterogeneous results of former studies.

The role of exosomes in cancer metastasis

Exosomes are small membrane vesicles with a size ranging from 40 to 100nm. They can serve as functional mediators in cell interaction leading to cancer metastasis. Metastasis is a complex multistep process of cancer cell invasion, survival in blood vessels, attachment to and colonization of the host organ. Exosomes influence every step of this cascade and can be targeted by oncological treatment. This review highlights the role of exosomes in the various steps of the metastatic cascade and how exosome dependent pathways can be targeted as therapeutic approach or used for liquid biopsies.

A COL11A1-correlated pan-cancer gene signature of activated fibroblasts for the prioritization of therapeutic targets

Although cancer-associated fibroblasts (CAFs) are viewed as a promising therapeutic target, the design of rational therapy has been hampered by two key obstacles. First, attempts to ablate CAFs have resulted in significant toxicity because currently used biomarkers cannot effectively distinguish activated CAFs from non-cancer associated fibroblasts and mesenchymal progenitor cells. Second, it is unclear whether CAFs in different organs have different molecular and functional properties that necessitate organ-specific therapeutic designs. Our analyses uncovered COL11A1 as a highly specific biomarker of activated CAFs. Using COL11A1 as a 'seed', we identified co-expressed genes in 13 types of primary carcinoma in The Cancer Genome Atlas. We demonstrated that a molecular signature of activated CAFs is conserved in epithelial cancers regardless of organ site and transforming events within cancer cells, suggesting that targeting fibroblast activation should be effective in multiple cancers. We prioritized several potential pan-cancer therapeutic targets that are likely to have high specificity for activated CAFs and minimal toxicity in normal tissues.

Stiffened Extracellular Matrix and Signaling from Stromal Fibroblasts via Osteoprotegerin Regulate Tumor Cell Invasion in a 3-D Tumor in Situ Model

Several changes have been described in the stroma surrounding a tumor, including changes in cellular composition, altered extracellular matrix composition and organization, and increases in stiffness. Tumor cells are influenced by the composition, organization, and mechanical properties of the microenvironment, and by signals from stromal cells. Here we sought to test whether signaling from stromal fibroblasts and/or the small change in stiffness observed in vivo surrounding epithelial tumors regulates tumor cell invasion from a model of a tumor in situ. We generated a novel tumor in situ model system in which a tumor spheroid is encased within a collagen-IV containing membrane and further encased within a collagen-I matrix of in vivo stiffness with or without fibroblasts. Effects of the matrix, fibroblasts or fibroblast signals were determined by observing the invasion of tumor cells into the matrix. Effects of reciprocal tumor cell signaling upon fibroblasts were determined by observing markers of fibroblast activation. We found that a stiffened matrix led to increased dissemination of MDA-MB-231 cells from tumor spheroids when no fibroblasts were present and that MCF10A cells maintained a more normal organization with a stiffened matrix. The presence of fibroblasts, or fibroblast conditioned media, attenuated the effect upon MDA-MB-231 cells. We also observed an attenuation of fibroblast activation associated gene expression in the presence of MDA-MB-231 cells, with a paradoxical increase in activation associated contractile activity. Furthermore, we identified osteoprotegerin as a soluble factor released by fibroblasts in the stiffened environment that is key to the inhibition of cell invasion.

FBW7 suppression leads to SOX9 stabilization and increased malignancy in medulloblastoma

SOX9 is a master transcription factor that regulates development and stem cell programs. However, its potential oncogenic activity and regulatory mechanisms that control SOX9 protein stability are poorly understood. Here, we show that SOX9 is a substrate of FBW7, a tumor suppressor, and a SCF (SKP1/CUL1/F‐box)‐type ubiquitin ligase. FBW7 recognizes a conserved degron surrounding threonine 236 (T236) in SOX9 that is phosphorylated by GSK3 kinase and consequently degraded by SCF^FBW7α. Failure to degrade SOX9 promotes migration, metastasis, and treatment resistance in medulloblastoma, one of the most common childhood brain tumors. FBW7 is either mutated or downregulated in medulloblastoma, and in cases where FBW7 mRNA levels are low, SOX9 protein is significantly elevated and this phenotype is associated with metastasis at diagnosis and poor patient outcome. Transcriptional profiling of medulloblastoma cells expressing a degradation‐resistant SOX9 mutant reveals activation of pro‐metastatic genes and genes linked to cisplatin resistance. Finally, we show that pharmacological inhibition of PI3K/AKT/mTOR pathway activity destabilizes SOX9 in a GSK3/FBW7‐dependent manner, rendering medulloblastoma cells sensitive to cytostatic treatment.

The actin crosslinking protein palladin modulates force generation and mechanosensitivity of tumor associated fibroblasts

Cells organize actin filaments into higher-order structures by regulating the composition, distribution and concentration of actin crosslinkers. Palladin is an actin crosslinker found in the lamellar actin network and stress fibers, which are critical for mechanosensing of the environment. Palladin also serves as a molecular scaffold for α-actinin, another key actin crosslinker. By virtue of its close interactions with actomyosin structures in the cell, palladin may play an important role in cell mechanics. However, the role of palladin in cellular force generation and mechanosensing has not been studied. Here, we investigate the role of palladin in regulating the plasticity of the actin cytoskeleton and cellular force generation in response to alterations in substrate stiffness. Traction force microscopy revealed that tumor-associated fibroblasts generate larger forces on substrates of increased stiffness. Contrary to expectations, knocking down palladin increased the forces generated by cells and inhibited their ability to sense substrate stiffness for very stiff gels. This was accompanied by significant differences in actin organization, adhesion dynamics and altered myosin organization in palladin knock-down cells. Our results suggest that actin crosslinkers such as palladin and myosin motors coordinate for optimal cell function and to prevent aberrant behavior as in cancer metastasis.

Palladin mediates stiffness-induced fibroblast activation in the tumor microenvironment

Mechanical properties of the tumor microenvironment have emerged as key factors in tumor progression. It has been proposed that increased tissue stiffness can transform stromal fibroblasts into carcinoma-associated fibroblasts. However, it is unclear whether the three to five times increase in stiffness seen in tumor-adjacent stroma is sufficient for fibroblast activation. In this study we developed a three-dimensional (3D) hydrogel model with precisely tunable stiffness and show that a physiologically relevant increase in stiffness is sufficient to lead to fibroblast activation. We found that soluble factors including CC-motif chemokine ligand (CCL) chemokines and fibronectin are necessary for this activation, and the combination of C-C chemokine receptor type 4 (CCR4) chemokine receptors and β1 and β3 integrins are necessary to transduce these chemomechanical signals. We then show that these chemomechanical signals lead to the gene expression changes associated with fibroblast activation via a network of intracellular signaling pathways that include focal adhesion kinase (FAK) and phosphoinositide 3-kinase (PI3K). Finally, we identify the actin-associated protein palladin as a key node in these signaling pathways that result in fibroblast activation.

Redox-Sensitive Regulation of Myocardin-Related Transcription Factor (MRTF-A) Phosphorylation via Palladin in Vascular Smooth Muscle Cell Differentiation Marker Gene Expression

Vascular smooth muscle cells (VSMCs) undergo a phenotypic switch from a differentiated to synthetic phenotype in cardiovascular diseases such as atherosclerosis and restenosis. Our previous studies indicate that transforming growth factor-β (TGF-β) helps to maintain the differentiated phenotype by regulating expression of pro-differentiation genes such as smooth muscle α-actin (SMA) and Calponin (CNN) through reactive oxygen species (ROS) derived from NADPH oxidase 4 (Nox4) in VSMCs. In this study, we investigated the relationship between Nox4 and myocardin-related transcription factor-A (MRTF-A), a transcription factor known to be important in expression of smooth muscle marker genes. Previous work has shown that MRTF-A interacts with the actin-binding protein, palladin, although how this interaction affects MRTF-A function is unclear, as is the role of phosphorylation in MRTF-A activity. We found that Rho kinase (ROCK)-mediated phosphorylation of MRTF-A is a key event in the regulation of SMA and CNN in VSMCs and that this phosphorylation depends upon Nox4-mediated palladin expression. Knockdown of Nox4 using siRNA decreases TGF-β -induced palladin expression and MRTF-A phosphorylation, suggesting redox-sensitive regulation of this signaling pathway. Knockdown of palladin also decreases MRTF-A phosphorylation. These data suggest that Nox4-dependent palladin expression and ROCK regulate phosphorylation of MRTF-A, a critical factor in the regulation of SRF responsive gene expression.

Stromal Palladin Expression Is an Independent Prognostic Factor in Pancreatic Ductal Adenocarcinoma

It has been clear that cancer-associated fibroblasts (CAFs) in the tumor microenvironment play an important role in pancreatic ductal adenocarcinoma (PDAC) progression. However, how CAFs relate to the patients' prognosis and the effects of chemoradiation therapy (CRT) has not been fully investigated. Tissue microarrays (TMAs) representing 167 resected PDACs without preoperative treatment were used for immunohistochemical studies (IHC) of palladin, α-smooth muscle actin (SMA), and podoplanin. Correlations between the expression levels of these markers and clinicopathological findings were analyzed statistically. Whole sections of surgical specimens from PDACs with and without preoperative CRT, designated as the chemotherapy-first group (CF, n = 19) and the surgery-first group (SF, n = 21), respectively, were also analyzed by IHC. In TMAs, the disease-specific survival rate (DSS) at 5 years for all 167 cases was 23.1%. Seventy cases (41.9%) were positive for palladin and had significantly lower DSS (p = 0.0430). α-SMA and podoplanin were positive in 167 cases (100%) and 131 cases (78.4%), respectively, and they were not significantly associated with DSS. On multivariable analysis, palladin expression was an independent poor prognostic factor (p = 0.0243, risk ratio 1.60). In the whole section study, palladin positivity was significantly lower (p = 0.0037) in the CF group (5/19) with a significantly better DSS (p = 0.0144) than in the SF group (16/22), suggesting that stromal palladin expression is a surrogate indicator of the treatment effect after chemoradiation therapy.

Twist1-induced activation of human fibroblasts promotes matrix stiffness by upregulating palladin and collagen α1(VI)

The transcription factor Twist1 is involved in the epithelial-mesenchymal transition and contributes to cancer metastasis through mostly unknown mechanisms. In colorectal cancer, Twist1 expression is mainly restricted to the tumor stroma. We found that human fibroblast cell lines stably transfected with Twist1 acquired characteristics of activated cancer-associated fibroblasts (CAFs), such as hyperproliferation, an increased ability to migrate and an alignment of the actin cytoskeleton. Further, Twist1-activated fibroblasts promoted increased matrix stiffness. Using quantitative proteomics, we identified palladin and collagen α1(VI) as two major mediators of the Twist1 effects in fibroblast cell lines. Co-immunoprecipitation studies indicated that palladin and Twist1 interact within the nucleus, suggesting that palladin could act as a transcription regulator. Palladin was found to be more relevant for the cellular biomechanical properties, orientation and polarity, and collagen α1(VI) for the migration and invasion capacity, of Twist1-activated fibroblasts. Both palladin and collagen α1(VI) were observed to be overexpressed in colorectal CAFs and to be associated with poor colorectal cancer patient survival and relapse prediction. Our results demonstrate that Twist1-expressing fibroblasts mimic the properties of CAFs present at the tumor invasive front, which likely explains the prometastatic activities of Twist1. Twist1 appears to require both palladin and collagen α1(VI) as downstream effectors for its prometastatic effects, which could be future therapeutic targets in cancer metastasis.

Relationship between ultrasound elastography and myofibroblast distribution in breast cancer and its clinical significance

The study investigated the relationship between ultrasound elastography (USE) scoring and myofibroblast distribution with expression features of α-SMA + /CD34− in patients of Uyghur and Han ethnicities with breast masses in Xinjiang, China. The data was used to evaluate its clinical significance in the early diagnosis of breast cancer. A total of 300 patients with breast masses were included in the study, which involved conventional sonography and USE, with histopathologic diagnosis as the reference standard. Myofibroblast distribution was investigated by detecting the expression levels of α-SMA and CD34 in lesions using immunohistochemistry and real-time PCR. Out of 300 lesions, 185 were histologically malignant and 115 benign. The mean elasticity score for malignant lesions was significantly higher than for benign lesions. The expression level of α-SMA was elevated while the expression level of CD34 was lower in malignancies, compared with benign lesions. The expression of α-SMA was positively associated with the USE scores, while a negative relationship was observed between CD34 expression and USE scoring. The combination of USE and molecular diagnosis provides a promising modality for the early diagnosis and evaluation of the risks in particular types of breast cancer.

Diagnosis and Management of Hereditary Pancreatic Cancer

Hereditary pancreatic cancer can be diagnosed through family history and/or a personal history of pancreatitis or clinical features suggesting one of the known pancreatic cancer predisposition syndromes. This chapter describes the currently known hereditary pancreatic cancer predisposition syndromes, including Peutz-Jeghers syndrome, familial atypical multiple mole melanoma, hereditary breast and ovarian cancer, Li-Fraumeni syndrome, hereditary non-polyposis colon cancer and familial adenomatous polyposis. Strategies for genetic testing for hereditary pancreatic cancer and the appropriate options for surveillance and cancer risk reduction are discussed. Finally, ongoing research and future directions in the diagnosis and management of hereditary pancreatic cancer will be considered.

Palladin expression is a conserved characteristic of the desmoplastic tumor microenvironment and contributes to altered gene expression

The stroma surrounding solid tumors contributes in complex ways to tumor progression. Cancer-associated fibroblasts (CAFs) are the predominant cell type in the tumor stroma. Previous studies have shown that the actin-binding protein palladin is highly expressed in the stroma of pancreas tumors, but the interpretation of these results is complicated by the fact that palladin exists as multiple isoforms. In the current study, the expression and localization of palladin isoform 4 was examined in normal specimens and adenocarcinomas of human pancreas, lung, colon, and stomach samples. Immunohistochemistry with isoform-selective antibodies revealed that expression of palladin isoform 4 was higher in adenocarcinomas versus normal tissues, and highest in CAFs. Immunohistochemistry staining revealed that palladin was present in both the cytoplasm and the nucleus of CAFs, and this was confirmed using immunofluorescence staining and subcellular fractionation of a pancreatic CAF cell line. To investigate the functional significance of nuclear palladin, RNA Seq analysis of palladin knockdown CAFs versus control CAFs was performed, and the results showed that palladin regulates the expression of genes involved in the biosynthesis and assembly of collagen, and organization of the extracellular matrix. These results suggested that palladin isoform 4 may play a conserved role in establishing the phenotype of CAFs in multiple tumor types.

Regulation of invadopodia by the tumor microenvironment

The tumor microenvironment consists of stromal cells, extracellular matrix (ECM), and signaling molecules that communicate with cancer cells. As tumors grow and develop, the tumor microenvironment changes. In addition, the tumor microenvironment is not only influenced by signals from tumor cells, but also stromal components contribute to tumor progression and metastasis by affecting cancer cell function. One of the mechanisms that cancer cells use to invade and metastasize is mediated by actin-rich, proteolytic structures called invadopodia. Here, we discuss how signals from the tumor environment, including growth factors, hypoxia, pH, metabolism, and stromal cell interactions, affect the formation and function of invadopodia to regulate cancer cell invasion and metastasis. Understanding how the tumor microenvironment affects invadopodia biology could aid in the development of effective therapeutics to target cancer cell invasion and metastasis.

Stromal fibroblasts facilitate cancer cell invasion by a novel invadopodia-independent matrix degradation process

Metastatic invasion of tumors into peripheral tissues is known to rely upon protease-mediated degradation of the surrounding stroma. This remodeling process uses complex, actin-based, specializations of the plasma membrane termed invadopodia that act both to sequester and release matrix metalloproteinases. Here we report that cells of mesenchymal origin, including tumor-associated fibroblasts, degrade substantial amounts of surrounding matrix by a mechanism independent of conventional invadopodia. These degradative sites lack the punctate shape of conventional invadopodia to spread along the cell base and are reticular and/or fibrous in character. In marked contrast to invadopodia, this degradation does not require the action of Src kinase, Cdc42 or Dyn2. Rather, inhibition of Dyn2 causes a marked upregulation of stromal matrix degradation. Further, expression and activity of matrix metalloproteinases are differentially regulated between tumor cells and stromal fibroblasts. This matrix remodeling by fibroblasts increases the invasive capacity of tumor cells, thereby illustrating how the tumor microenvironment can contribute to metastasis. These findings provide evidence for a novel matrix remodeling process conducted by stromal fibroblasts that is substantially more effective than conventional invadopodia, distinct in structural organization and regulated by disparate molecular mechanisms.

Stromal expression of heat-shock protein 27 is associated with worse clinical outcome in patients with colorectal cancer lung metastases

Background

Pulmonary metastases are common in patients with primary colorectal cancer (CRC). Heat-shock protein 27 (Hsp27) is upregulated in activated fibroblasts during wound healing and systemically elevated in various diseases. Cancer-associated fibroblasts (CAFs) are also thought to play a role as prognostic and predictive markers in various malignancies including CRC. Surprisingly, the expression of Hsp27 has never been assessed in CAFs. Therefore we aimed to investigate the expression level of Hsp27 in CAFs and its clinical implications in patients with CRC lung metastases.

Methods

FFPE tissue samples from 51 pulmonary metastases (PMs) and 33 paired primary tumors were evaluated for alpha-SMA, CD31, Hsp27 and vimentin expression by immunohistochemistry and correlated with clinicopathological variables. 25 liver metastases served as control group. Moreover, serum samples (n=10) before and after pulmonary metastasectomy were assessed for circulating phospho-Hsp27 and total Hsp27 by ELISA.

Results

Stromal expression of Hsp27 was observed in all PM and showed strong correlation with alpha-SMA (P<0.001) and vimentin (P<0.001). Strong stromal Hsp27 was associated with higher microvessel density in primary CRC and PM. Moreover, high stromal Hsp27 and αSMA expression were associated with decreased recurrence-free survival after pulmonary metastasectomy (P=0.018 and P=0.008, respectively) and overall survival (P=0.031 and P=0.017, respectively). Serum levels of phospho- and total Hsp27 dropped after metastasectomy to levels comparable to healthy controls.

Conclusions

Herein we describe for the first time that Hsp27 is highly expressed in tumor stroma of CRC. Stromal α-SMA and Hsp27 expressions correlate with the clinical outcome after pulmonary metastasectomy. Moreover, serum Hsp27 might pose a future marker for metastatic disease in CRC.

Molecular mechanism underlying the tumor-promoting functions of carcinoma-associated fibroblasts

Tumor microenvironment is composed of all the untransformed elements in the vicinity of tumor, mainly including a large number of stromal cells and extracellular matrix proteins, which play an active role in most solid tumor initiation and progression. Carcinoma-associated fibroblasts (CAFs), one of the most common stromal cell types in the tumor microenvironment, have been demonstrated to be involved in tumor growth, invasion, and metastasis. Therefore, they are becoming a promising target for anti-cancer therapies. In this review, we firstly summarize the current understandings of CAFs' molecular biology, including the heterogeneous cellular origins and molecular markers, and then, we focus on reviewing their various tumor-promoting phenotypes involved in complex mechanisms, which can be summarized to the CAF-conveyed paracrine signals in tumor cells, cancer stem cells, and metastasis-initiating cancer cells, as well as the CAF-enhanced extrinsic tumor-promoting processes including angiogenesis, extracellular matrix remodeling, and tumor-related inflammation; finally, we describe the available directions of CAF-based target therapy and suggest research areas which need to be further explored so as to deepen the understanding of tumor evolution and provide new therapeutic targets for cancer treatment.

Proteins associated with pancreatic cancer survival in patients with resectable pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal disease with a dismal prognosis. However, while most patients die within the first year of diagnosis, very rarely, a few patients can survive for >10 years. Better understanding the molecular characteristics of the pancreatic adenocarcinomas from these very-long-term survivors (VLTS) may provide clues for personalized medicine and improve current pancreatic cancer treatment. To extend our previous investigation, we examined the proteomes of individual pancreas tumor tissues from a group of VLTS patients (survival ≥10 years) and short-term survival patients (STS, survival <14 months). With a given analytical sensitivity, the protein profile of each pancreatic tumor tissue was compared to reveal the proteome alterations that may be associated with pancreatic cancer survival. Pathway analysis of the differential proteins identified suggested that MYC, IGF1R and p53 were the top three upstream regulators for the STS-associated proteins, and VEGFA, APOE and TGFβ-1 were the top three upstream regulators for the VLTS-associated proteins. Immunohistochemistry analysis using an independent cohort of 145 PDAC confirmed that the higher abundance of ribosomal protein S8 (RPS8) and prolargin (PRELP) were correlated with STS and VLTS, respectively. Multivariate Cox analysis indicated that 'High-RPS8 and Low-PRELP' was significantly associated with shorter survival time (HR=2.69, 95% CI 1.46-4.92, P=0.001). In addition, galectin-1, a previously identified protein with its abundance aversely associated with pancreatic cancer survival, was further evaluated for its significance in cancer-associated fibroblasts. Knockdown of galectin-1 in pancreatic cancer-associated fibroblasts dramatically reduced cell migration and invasion. The results from our study suggested that PRELP, LGALS1 and RPS8 might be significant prognostic factors, and RPS8 and LGALS1 could be potential therapeutic targets to improve pancreatic cancer survival if further validated.

TSPAN12 is a critical factor for cancer-fibroblast cell contact-mediated cancer invasion

Communication between cancer cells and their microenvironment controls cancer progression. Although the tumor suppressor p53 functions in a cell-autonomous manner, it has also recently been shown to function in a non-cell-autonomous fashion. Although functional defects have been reported in p53 in stromal cells surrounding cancer, including mutations in the p53 gene and decreased p53 expression, the role of p53 in stromal cells during cancer progression remains unclear. We herein show that the expression of α-smooth muscle actin (α-SMA), a marker of cancer-associated fibroblasts (CAFs), was increased by the ablation of p53 in lung fibroblasts. CAFs enhanced the invasion and proliferation of lung cancer cells when cocultured with p53-depleted fibroblasts and required contact between cancer and stromal cells. A comprehensive analysis using a DNA chip revealed that tetraspanin 12 (TSPAN12), which belongs to the tetraspanin protein family, was derepressed by p53 knockdown. TSPAN12 knockdown in p53-depleted fibroblasts inhibited cancer cell proliferation and invasion elicited by coculturing with p53-depleted fibroblasts in vitro, and inhibited tumor growth in vivo. It also decreased CXC chemokine ligand 6 (CXCL6) secretion through the β-catenin signaling pathway, suggesting that cancer cell contact with TSPAN12 in fibroblasts transduced β-catenin signaling into fibroblasts, leading to the secretion of CXCL6 to efficiently promote invasion. These results suggest that stroma-derived p53 plays a pivotal role in epithelial cancer progression and that TSPAN12 and CXCL6 are potential targets for lung cancer therapy.

The increasing roles of epigenetics in breast cancer: Implications for pathogenicity, biomarkers, prevention and treatment

Nowadays, the mechanisms governing the occurrence of cancer are thought to be the consequence not only of genetic defects but also of epigenetic modifications. Therefore, epigenetic has become a very attractive and increasingly investigated field of research in order to find new ways of prevention and treatment of neoplasia, and this is particularly the case for breast cancer (BC). Thus, this review will first develop the main known epigenetic modifications that can occur in cancer and then expose the future role that control of epigenetic modifications might play in prevention, prognostication, follow-up and treatment of BC. Indeed, epigenetic biomarkers found in peripheral blood might become new tools to detect BC, to define its prognostic and to predict its outcome, whereas epi-drugs might have an increasing potential of development in the next future. However, if DNA methyltransferase inhibitors and histone desacetylase inhibitors have shown encouraging results in BC, their action remains nonspecific. Thus, additional clinical studies are needed to evaluate more precisely the effects of these molecules, even if they have provided encouraging results in cotreatment and combined therapies. This review will also deal with the potential of RNA interference (RNAi) as epi-drugs. Finally, we will focus on the potential prevention of BC through epigenetic based on diet and we will particularly develop the possible place of isothiocyanates from cruciferous vegetables or of Genistein from soybean in a dietary program that might potentially reduce the risk of BC in large populations.

Actin cross-linking protein palladin and spermatogenesis

In the seminiferous epithelium of the mammalian testis, the most distinctive ultrastructure is the extensive bundles of actin filaments that lie near the Sertoli-spermatid interface and the Sertoli-Sertoli cell interface known as the apical ectoplasmic specialization (apical ES) and the basal ES, respectively. These actin filament bundles not only confer strong adhesion at these sites, they are uniquely found in the testis. Recent studies have shown that ES also confers spermatid and Sertoli cell polarity in the seminiferous epithelium during the epithelial cycle. While these junctions were first described in the 1970s, there are few functional studies in the literature to examine the regulation of these actin filament bundles. It is conceivable that these actin filament bundles at the ES undergo extensive re-organization to accommodate changes in location of developing spermatids during spermiogenesis as spermatids are transported across the seminiferous epithelium. Additionally, these actin filaments are rapidly reorganized during BTB restructuring to accommodate the transit of preleptotene spermatocytes across the barrier at stage VIII of the epithelial cycle. Thus, actin binding and regulatory proteins are likely involved in these events to confer changes in F-actin organization at these sites. Interestingly, there are no reports in the field to study these regulatory proteins until recently. Herein, we summarize some of the latest findings in the field regarding a novel actin cross-linker and actin-bundling protein called palladin. We also discuss in this opinion article the likely role of palladin in regulating actin filament bundles at the ES during spermatogenesis, highlighting the significant of palladin and how this protein is plausibly working in concert with other actin-binding/regulatory proteins and components of polarity proteins to regulate the cyclic events of actin organization and re-organization during the epithelial cycle of spermatogenesis. We also propose a hypothetic model by which palladin regulates ES restructuring during the epithelial cycle of spermatogenesis.

Fibroblast heterogeneity in the cancer wound

Dr. Tuveson and colleagues provide a comprehensive review on the fundamental role of cancer-associated fibroblasts in shaping the tumor microenvironment and promoting tumor initiation and progression.

Fibroblasts regulate the structure and function of healthy tissues, participate transiently in tissue repair after acute inflammation, and assume an aberrant stimulatory role during chronic inflammatory states including cancer. Such cancer-associated fibroblasts (CAFs) modulate the tumor microenvironment and influence the behavior of neoplastic cells in either a tumor-promoting or tumor-inhibiting manner. These pleiotropic functions highlight the inherent plasticity of fibroblasts and may provide new avenues to understand and therapeutically intervene in malignancies. We discuss the emerging themes of CAF biology in the context of tumorigenesis and therapy.

Fibroblast heterogeneity in the cancer wound

Fibroblasts regulate the structure and function of healthy tissues, participate transiently in tissue repair after acute inflammation, and assume an aberrant stimulatory role during chronic inflammatory states including cancer. Such cancer-associated fibroblasts (CAFs) modulate the tumor microenvironment and influence the behavior of neoplastic cells in either a tumor-promoting or tumor-inhibiting manner. These pleiotropic functions highlight the inherent plasticity of fibroblasts and may provide new avenues to understand and therapeutically intervene in malignancies. We discuss the emerging themes of CAF biology in the context of tumorigenesis and therapy.

Fibroblast heterogeneity in the cancer wound

Fibroblasts regulate the structure and function of healthy tissues, participate transiently in tissue repair after acute inflammation, and assume an aberrant stimulatory role during chronic inflammatory states including cancer. Such cancer-associated fibroblasts (CAFs) modulate the tumor microenvironment and influence the behavior of neoplastic cells in either a tumor-promoting or tumor-inhibiting manner. These pleiotropic functions highlight the inherent plasticity of fibroblasts and may provide new avenues to understand and therapeutically intervene in malignancies. We discuss the emerging themes of CAF biology in the context of tumorigenesis and therapy.

Fibroblast heterogeneity in the cancer wound

Fibroblasts regulate the structure and function of healthy tissues, participate transiently in tissue repair after acute inflammation, and assume an aberrant stimulatory role during chronic inflammatory states including cancer. Such cancer-associated fibroblasts (CAFs) modulate the tumor microenvironment and influence the behavior of neoplastic cells in either a tumor-promoting or tumor-inhibiting manner. These pleiotropic functions highlight the inherent plasticity of fibroblasts and may provide new avenues to understand and therapeutically intervene in malignancies. We discuss the emerging themes of CAF biology in the context of tumorigenesis and therapy.

Fibroblast heterogeneity in the cancer wound

Fibroblasts regulate the structure and function of healthy tissues, participate transiently in tissue repair after acute inflammation, and assume an aberrant stimulatory role during chronic inflammatory states including cancer. Such cancer-associated fibroblasts (CAFs) modulate the tumor microenvironment and influence the behavior of neoplastic cells in either a tumor-promoting or tumor-inhibiting manner. These pleiotropic functions highlight the inherent plasticity of fibroblasts and may provide new avenues to understand and therapeutically intervene in malignancies. We discuss the emerging themes of CAF biology in the context of tumorigenesis and therapy.

Fibroblast heterogeneity in the cancer wound

Fibroblasts regulate the structure and function of healthy tissues, participate transiently in tissue repair after acute inflammation, and assume an aberrant stimulatory role during chronic inflammatory states including cancer. Such cancer-associated fibroblasts (CAFs) modulate the tumor microenvironment and influence the behavior of neoplastic cells in either a tumor-promoting or tumor-inhibiting manner. These pleiotropic functions highlight the inherent plasticity of fibroblasts and may provide new avenues to understand and therapeutically intervene in malignancies. We discuss the emerging themes of CAF biology in the context of tumorigenesis and therapy.