Regulation of pancreatic function by connective tissue growth factor (CTGF, CCN2). Cytokine Growth Factor Rev. 2013;24:59-68. [PMID: 22884427 DOI: 10.1016/j.cytogfr.2012.07.001]

Therapeutic strategies to target connective tissue growth factor in fibrotic lung diseases

The treatment of interstitial lung diseases, including idiopathic pulmonary fibrosis (IPF), remains challenging as current available antifibrotic agents are not effective in halting disease progression. Connective tissue growth factor (CTGF), also known as cellular communication factor 2 (CCN2), is a member of the CCN family of proteins that regulates cell signaling through cell surface receptors such as integrins, the activity of cytokines/growth factors, and the turnover of extracellular matrix (ECM) proteins. Accumulating evidence indicates that CTGF plays a crucial role in promoting lung fibrosis through multiple processes, including inducing transdifferentiation of fibroblasts to myofibroblasts, epithelial-mesenchymal transition (EMT), and cooperating with other fibrotic mediators such as TGF-β. Increased expression of CTGF has been observed in fibrotic lungs and inhibiting CTGF signaling has been shown to suppress lung fibrosis in several animal models. Thus, the CTGF signaling pathway is emerging as a potential therapeutic target in IPF and other pulmonary fibrotic conditions. This review provides a comprehensive overview of the current evidence on the pathogenic role of CTGF in pulmonary fibrosis and discusses the current therapeutic agents targeting CTGF using a systematic review approach.

Positive Regulation of S-Adenosylmethionine on Chondrocytic Differentiation via Stimulation of Polyamine Production and the Gene Expression of Chondrogenic Differentiation Factors

S-adenosylmethionine (SAM) is considered to be a useful therapeutic agent for degenerative cartilage diseases, although its mechanism is not clear. We previously found that polyamines stimulate the expression of differentiated phenotype of chondrocytes. We also found that the cellular communication network factor 2 (CCN2) played a huge role in the proliferation and differentiation of chondrocytes. Therefore, we hypothesized that polyamines and CCN2 could be involved in the chondroprotective action of SAM. In this study, we initially found that exogenous SAM enhanced proteoglycan production but not cell proliferation in human chondrocyte-like cell line-2/8 (HCS-2/8) cells. Moreover, SAM enhanced gene expression of cartilage-specific matrix (aggrecan and type II collagen), Sry-Box transcription factor 9 (SOX9), CCN2, and chondroitin sulfate biosynthetic enzymes. The blockade of the methionine adenosyltransferase 2A (MAT2A) enzyme catalyzing intracellular SAM biosynthesis restrained the effect of SAM on chondrocytes. The polyamine level in chondrocytes was higher in SAM-treated culture than control culture. Additionally, Alcian blue staining and RT-qPCR indicated that the effects of SAM on the production and gene expression of aggrecan were reduced by the inhibition of polyamine synthesis. These results suggest that the stimulation of polyamine synthesis and gene expression of chondrogenic differentiation factors, such as CCN2, account for the mechanism underlying the action of SAM on chondrocytes.

Generation of β-like cell subtypes from differentiated human induced pluripotent stem cells in 3D spheroids

Since the identification of four different pancreatic β-cell subtypes and bi-hormomal cells playing a role in the diabetes pathogenesis, the search for in vitro models that mimics such cells heterogeneity became a key priority in experimental and clinical diabetology. We investigated the potential of human induced pluripotent stem cells to lead to the development of the different β-cells subtypes in honeycomb microwell-based 3D spheroids. The glucose-stimulated insulin secretion confirmed the spheroids functionality. Then, we performed a single cell RNA sequencing of the spheroids. Using a knowledge-based analysis with a stringency on the pancreatic markers, we extracted the β-cells INS+/UCN3+ subtype (11%; β1-like cells), the INS+/ST8SIA1+/CD9- subtype (3%, β3-like cells) and INS+/CD9+/ST8SIA1-subtype (1%; β2-like cells) consistently with literature findings. We did not detect the INS+/ST8SIA1+/CD9+ cells (β4-like cells). Then, we also identified four bi-hormonal cells subpopulations including δ-like cells (INS+/SST+, 6%), γ-like cells (INS+/PPY+, 3%), α-like-cells (INS+/GCG+, 6%) and ε-like-cells (INS+/GHRL+, 2%). Using data-driven clustering, we extracted four progenitors' subpopulations (with the lower level of INS gene) that included one population highly expressing inhibin genes (INHBA+/INHBB+), one population highly expressing KCNJ3+/TPH1+, one population expressing hepatocyte-like lineage markers (HNF1A+/AFP+), and one population expressing stem-like cell pancreatic progenitor markers (SOX2+/NEUROG3+). Furthermore, among the cycling population we found a large number of REST+ cells and CD9+ cells (CD9+/SPARC+/REST+). Our data confirm that our differentiation leads to large β-cell heterogeneity, which can be used for investigating β-cells plasticity under physiological and pathophysiological conditions.

Recent progress on the role of cellular communication network factors (CCN) 3, 4 and 6 in regulating adiposity, liver fibrosis and pancreatic islets

CCN/WISP (cellular communication network factors, or Wnt-inducted secreted proteins) family of proteins consists of six extracellular matrix (ECM)-associated proteins that regulate development, cell adhesion and proliferation, ECM remodeling, inflammation, and tumorigenesis. In the last two decades, metabolic regulation by these matricellular proteins has been studied extensively, several excellent reviews have covered the roles of CCN1, -2 and - 5. In this brief review, we will focus on those lesser-known members and more recent discoveries, together with other recent articles presenting a more complete picture of the current state of knowledge. We have found that CCN2, -4, and - 5 promote pancreatic islet function, while CCN3 plays a unique and negative role. CCN3 and - 4 are pro-adiposity leading to insulin resistance, but CCN5 and - 6 are anti-adiposity. While CCN2 and - 4 promote tissue fibrosis and inflammation, all other four members are clearly anti-fibrotic. As for cellular signaling, they are known to interact with integrins, other cell membrane proteins and ECM thereby regulate Akt/protein kinase B, myocardin-related transcription factor (MRTF), and focal adhesion kinase. Yet, a cohesive mechanism of action to comprehensively explain those major functions is still lacking.

Chemoresistance in pancreatic ductal adenocarcinoma: Overcoming resistance to therapy

Pancreatic ductal adenocarcinoma (PDAC), a prominent cause of cancer deaths worldwide, is a highly aggressive cancer most frequently detected at an advanced stage that limits treatment options to systemic chemotherapy, which has provided only marginal positive clinical outcomes. More than 90% of patients with PDAC die within a year of being diagnosed. PDAC is increasing at a rate of 0.5-1.0% per year, and it is expected to be the second leading cause of cancer-related mortality by 2030. The resistance of tumor cells to chemotherapeutic drugs, which can be innate or acquired, is the primary factor contributing to the ineffectiveness of cancer treatments. Although many PDAC patients initially responds to standard of care (SOC) drugs they soon develop resistance caused partly by the substantial cellular heterogeneity seen in PDAC tissue and the tumor microenvironment (TME), which are considered key factors contributing to resistance to therapy. A deeper understanding of molecular mechanisms involved in PDAC progression and metastasis development, and the interplay of the TME in all these processes is essential to better comprehend the etiology and pathobiology of chemoresistance observed in PDAC. Recent research has recognized new therapeutic targets ushering in the development of innovative combinatorial therapies as well as enhancing our comprehension of several different cell death pathways. These approaches facilitate the lowering of the therapeutic threshold; however, the possibility of subsequent resistance development still remains a key issue and concern. Discoveries, that can target PDAC resistance, either alone or in combination, have the potential to serve as the foundation for future treatments that are effective without posing undue health risks. In this chapter, we discuss potential causes of PDAC chemoresistance and approaches for combating chemoresistance by targeting different pathways and different cellular functions associated with and mediating resistance.

The Role of MicroRNAs in Pancreatitis Development and Progression

Pancreatitis (acute and chronic) is an inflammatory disease associated with significant morbidity, including a high rate of hospitalization and mortality. MicroRNAs (miRs) are essential post-transcriptional modulators of gene expression. They are crucial in many diseases' development and progression. Recent studies have demonstrated aberrant miRs expression patterns in pancreatic tissues obtained from patients experiencing acute and chronic pancreatitis compared to tissues from unaffected individuals. Increasing evidence showed that miRs regulate multiple aspects of pancreatic acinar biology, such as autophagy, mitophagy, and migration, impact local and systemic inflammation and, thus, are involved in the disease development and progression. Notably, multiple miRs act on pancreatic acinar cells and regulate the transduction of signals between pancreatic acinar cells, pancreatic stellate cells, and immune cells, and provide a complex interaction network between these cells. Importantly, recent studies from various animal models and patients' data combined with advanced detection techniques support their importance in diagnosing and treating pancreatitis. In this review, we plan to provide an up-to-date summary of the role of miRs in the development and progression of pancreatitis.

Crosstalk between Pancreatic Cancer Cells and Cancer-Associated Fibroblasts in the Tumor Microenvironment Mediated by Exosomal MicroRNAs

Pancreatic ductal adenocarcinoma (PDAC) is one of the most malignant digestive tumors, characterized by a low rate of early diagnosis, strong invasiveness, and early metastasis. The abundant stromal cells, dense extracellular matrix, and lack of blood supply in PDAC limit the penetration of chemotherapeutic drugs, resulting in poor efficacy of the current treatment regimens. Cancer-associated fibroblasts (CAFs) are the major stromal cells in the tumor microenvironment. Tumor cells can secrete exosomes to promote the generation of activated CAFs, meanwhile exosomes secreted by CAFs help promote tumor progression. The aberrant expression of miRNAs in exosomes is involved in the interaction between tumor cells and CAFs, which provides the possibility for the application of exosomal miRNAs in the diagnosis and treatment of PDAC. The current article reviews the mechanism of exosomal miRNAs in the crosstalk between PDAC cells and CAFs in the tumor microenvironment, in order to improve the understanding of TME regulation and provide evidence for designing diagnostic and therapeutic targets against exosome miRNA in human PDAC.

Molecular and Genetic Interactions between CCN2 and CCN3 behind Their Yin-Yang Collaboration

Cellular communication network factor (CCN) 2 and 3 are the members of the CCN family that conduct the harmonized development of a variety of tissues and organs under interaction with multiple biomolecules in the microenvironment. Despite their striking structural similarities, these two members show contrastive molecular functions as well as temporospatial emergence in living tissues. Typically, CCN2 promotes cell growth, whereas CCN3 restrains it. Where CCN2 is produced, CCN3 disappears. Nevertheless, these two proteins collaborate together to execute their mission in a yin–yang fashion. The apparent functional counteractions of CCN2 and CCN3 can be ascribed to their direct molecular interaction and interference over the cofactors that are shared by the two. Recent studies have revealed the mutual negative regulation systems between CCN2 and CCN3. Moreover, the simultaneous and bidirectional regulatory system of CCN2 and CCN3 is also being clarified. It is of particular note that these regulations were found to be closely associated with glycolysis, a fundamental procedure of energy metabolism. Here, the molecular interplay and metabolic gene regulation that enable the yin–yang collaboration of CCN2 and CCN3 typically found in cartilage development/regeneration and fibrosis are described.

Cancer-Associated Fibroblasts and Tumor Cells in Pancreatic Cancer Microenvironment and Metastasis: Paracrine Regulators, Reciprocation and Exosomes

Simple Summary

Cancer-associated fibroblasts in the stromal tumor microenvironment play a key role in cancer progression, invasion, metastasis, and therapy resistance. Cancer-associated fibroblasts communicate with tumor cells through diverse factors, such as growth factors, hedgehog proteins, cytokines, and chemokines, regulating signaling activity in paracrine as well as paracrine-reciprocal ways. Furthermore, cancer-associated fibroblasts, not only tumor cells, secrete exosomes that drive pre-metastatic niche formation and metastasis.

Abstract

Pancreatic cancer is currently the fourth leading cause of cancer deaths in the United States, and the overall 5 year survival rate is still only around 10%. Pancreatic cancer exhibits a remarkable resistance to established therapeutic options such as chemotherapy and radiotherapy, in part due to the dense stromal tumor microenvironment, where cancer-associated fibroblasts are the major stromal cell type. Cancer-associated fibroblasts further play a key role in cancer progression, invasion, and metastasis. Cancer-associated fibroblasts communicate with tumor cells, not only through paracrine as well as paracrine-reciprocal signaling regulators but also by way of exosomes. In the current manuscript, we discuss intercellular mediators between cancer-associated fibroblasts and pancreatic cancer cells in a paracrine as well as paracrine-reciprocal manner. Further recent findings on exosomes in pancreatic cancer and metastasis are summarized.

Thrombocytopenia in COVID‑19 and vaccine‑induced thrombotic thrombocytopenia

The highly heterogeneous symptomatology and unpredictable progress of COVID-19 triggered unprecedented intensive biomedical research and a number of clinical research projects. Although the pathophysiology of the disease is being progressively clarified, its complexity remains vast. Moreover, some extremely infrequent cases of thrombotic thrombocytopenia following vaccination against SARS-CoV-2 infection have been observed. The present study aimed to map the signaling pathways of thrombocytopenia implicated in COVID-19, as well as in vaccine-induced thrombotic thrombocytopenia (VITT). The biomedical literature database, MEDLINE/PubMed, was thoroughly searched using artificial intelligence techniques for the semantic relations among the top 50 similar words (>0.9) implicated in COVID-19-mediated human infection or VITT. Additionally, STRING, a database of primary and predicted associations among genes and proteins (collected from diverse resources, such as documented pathway knowledge, high-throughput experimental studies, cross-species extrapolated information, automated text mining results, computationally predicted interactions, etc.), was employed, with the confidence threshold set at 0.7. In addition, two interactomes were constructed: i) A network including 119 and 56 nodes relevant to COVID-19 and thrombocytopenia, respectively; and ii) a second network containing 60 nodes relevant to VITT. Although thrombocytopenia is a dominant morbidity in both entities, three nodes were observed that corresponded to genes (AURKA, CD46 and CD19) expressed only in VITT, whilst ADAM10, CDC20, SHC1 and STXBP2 are silenced in VITT, but are commonly expressed in both COVID-19 and thrombocytopenia. The calculated average node degree was immense (11.9 in COVID-19 and 6.43 in VITT), illustrating the complexity of COVID-19 and VITT pathologies and confirming the importance of cytokines, as well as of pathways activated following hypoxic events. In addition, PYCARD, NLP3 and P2RX7 are key potential therapeutic targets for all three morbid entities, meriting further research. This interactome was based on wild-type genes, revealing the predisposition of the body to hypoxia-induced thrombosis, leading to the acute COVID-19 phenotype, the 'long-COVID syndrome', and/or VITT. Thus, common nodes appear to be key players in illness prevention, progression and treatment.

Metabolic Effects of CCN5/WISP2 Gene Deficiency and Transgenic Overexpression in Mice

CCN5/WISP2 is a matricellular protein, the expression of which is under the regulation of Wnt signaling and IGF-1. Our initial characterization supports the notion that CCN5 might promote the proliferation and survival of pancreatic β-cells and thus improve the metabolic profile of the animals. More recently, the roles of endogenous expression of CCN5 and its ectopic, transgenic overexpression on metabolic regulation have been revealed through two reports. Here, we attempt to compare the experimental findings from those studies, side-by-side, in order to further establish its roles in metabolic regulation. Prominent among the discoveries was that a systemic deficiency of CCN5 gene expression caused adipocyte hypertrophy, increased adipogenesis, and lipid accumulation, resulting in insulin resistance and glucose intolerance, which were further exacerbated upon high-fat diet feeding. On the other hand, the adipocyte-specific and systemic overexpression of CCN5 caused an increase in lean body mass, improved insulin sensitivity, hyperplasia of cardiomyocytes, and increased heart mass, but decreased fasting glucose levels. CCN5 is clearly a regulator of adipocyte proliferation and maturation, affecting lean/fat mass ratio and insulin sensitivity. Not all results from these models are consistent; moreover, several important aspects of CCN5 physiology are yet to be explored.

Nanomedicine Strategies to Enhance Tumor Drug Penetration in Pancreatic Cancer

Pancreatic cancer is one of the most malignant tumors with one of the worst survival rates due to its insidious onset and resistance to therapies. Most therapeutics show a desired anticancer effect in vitro; however, very poor efficacy in vivo because of the limited drug delivery and penetration into pancreatic tumors attributed to the abundance of the tumor stroma, ie, the fibrotic tumor microenvironment surrounding the cancer cells. For a better understanding of the challenges posed by the pancreatic tumor stroma, we outline the key features of the tumor microenvironment. Then we highlight major strategies used to tackle the challenges to improve drug penetration into the tumor and achieve enhanced efficacy (pre)clinically. Furthermore, we describe nanomedicine strategies to modulate the tumor stroma, degrade the extracellular matrix, and co-deliver multi-functional drugs, to improve the chemotherapeutics delivery and penetration into pancreatic tumors.

Evolution of Systemic Therapy in Metastatic Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma is characterized by early systemic dissemination, a complex tumor microenvironment, as well as significant intratumoral and intertumoral heterogeneity. Treatment options and survival in pancreatic ductal adenocarcinoma have improved steadily over the last 3 decades. Although cytotoxic chemotherapy is currently the mainstay of treatment for pancreatic ductal adenocarcinoma, evolving therapeutic strategies are aimed at targeting the tumor microenvironment, metabolism, and the tumor-host immune balance.

Dysregulation of PI3K and Hippo signaling pathways synergistically induces chronic pancreatitis via CTGF upregulation

The role of PI3K and Hippo signaling in chronic pancreatitis (CP) pathogenesis is unclear. Therefore, we assessed the involvement of these pathways in CP by examining the PI3K and Hippo signaling components PTEN and SAV1, respectively. We observed significant decreases in pancreatic PTEN and SAV1 levels in 2 murine CP models: repeated cerulein injection and pancreatic ductal ligation. Additionally, pancreas-specific deletion of Pten and Sav1 (DKO) induced CP in mice. Pancreatic connective tissue growth factor (CTGF) was markedly upregulated in both CP models and DKO mice, and pancreatic CCAAT/enhancer-binding protein-α (CEBPA) expression was downregulated in the CP models. Interestingly, in pancreatic acinar cells (PACs), CEBPA knockdown reduced PTEN and SAV1 and increased CTGF levels in vitro. Furthermore, CEBPA knockdown in PACs induced acinar-to-ductal metaplasia and activation of cocultured macrophages and pancreatic stellate cells. These results were mitigated by CTGF inhibition. CP in DKO mice was also ameliorated by Ctgf gene deletion, and cerulein-induced CP was alleviated by antibody-mediated CTGF neutralization. Finally, we observed significantly decreased PTEN, SAV1, and CEBPA and increased CTGF levels in human CP tissues compared with nonpancreatitis tissues. Taken together, our results indicate that dysregulation of PI3K and Hippo signaling induces CP via CTGF upregulation.

Targeting Growth Factor Signaling Pathways in Pancreatic Cancer: Towards Inhibiting Chemoresistance

Pancreatic cancer is one of the most deadly cancers, ranking amongst the top leading cause of cancer related deaths in developed countries. Features such as dense stroma microenvironment, abnormal signaling pathways, and genetic heterogeneity of the tumors contribute to its chemoresistant characteristics. Amongst these features, growth factors have been observed to play crucial roles in cancer cell survival, progression, and chemoresistance. Here we review the role of the individual growth factors in pancreatic cancer chemoresistance. Importantly, the interplay between the tumor microenvironment and chemoresistance is explored in the context of pivotal role played by growth factors. We further describe current and future potential therapeutic targeting of these factors.

Opportunities and delusions regarding drug delivery targeting pancreatic cancer-associated fibroblasts

A dense desmoplastic stroma formed by abundant extracellular matrix and stromal cells, including cancer-associated fibroblasts (CAFs) and immune cells, is a feature of pancreatic ductal adenocarcinoma (PDAC), one of the most lethal cancer types. As the dominant cellular component of the PDAC stroma, CAFs orchestrate intensive and biologically diverse crosstalk with pancreatic cancer cells and immune cells and contribute to a unique PDAC tumor microenvironment promoting cancer proliferation, metastasis, and resistance against both chemo- and immunotherapies. Therefore, CAFs and CAF-related mechanisms have emerged as promising targets for PDAC therapy. However, several clinical setbacks and accumulating knowledge of the PDAC stroma have revealed the heterogeneity and multifaceted biological roles of CAFs, and concerns regarding "what to deliver" and "how to deliver" have arisen when designing CAF-targeted drug delivery systems to specifically inhibit tumor-supporting CAFs without impairing tumor-restricting CAFs. In this review, we will discuss the complexity of CAFs in the PDAC stroma as well as the potential opportunities and common misconceptions regarding drug delivery efforts targeting PDAC CAFs.

Insights into the etiology and physiopathology of MODY5/HNF1B pancreatic phenotype with a mouse model of the human disease

Maturity-onset diabetes of the young type 5 (MODY5) is due to heterozygous mutations or deletion of HNF1B. No mouse models are currently available to recapitulate the human MODY5 disease. Here, we investigate the pancreatic phenotype of a unique MODY5 mouse model generated by heterozygous insertion of a human HNF1B splicing mutation at the intron-2 splice donor site in the mouse genome. This Hnf1bsp2/+ model generated with targeted mutation of Hnf1b mimicking the c.544+1G>T (T) mutation identified in humans, results in alternative transcripts and a 38% decrease of native Hnf1b transcript levels. As a clinical feature of MODY5 patients, the hypomorphic mouse model Hnf1bsp2/+ displays glucose intolerance. Whereas Hnf1bsp2/+ isolated islets showed no altered insulin secretion, we found a 65% decrease in pancreatic insulin content associated with a 30% decrease in total large islet volume and a 20% decrease in total β-cell volume. These defects were associated with a 30% decrease in expression of the pro-endocrine gene Neurog3 that we previously identified as a direct target of Hnf1b, showing a developmental etiology. As another clinical feature of MODY5 patients, the Hnf1bsp2/+ pancreases display exocrine dysfunction with hypoplasia. We observed chronic pancreatitis with loss of acinar cells, acinar-to-ductal metaplasia, and lipomatosis, with upregulation of signaling pathways and impaired acinar cell regeneration. This was associated with ductal cell deficiency characterized by shortened primary cilia. Importantly, the Hnf1bsp2/+ mouse model reproduces the pancreatic features of the human MODY5/HNF1B disease, providing a unique in vivo tool for molecular studies of the endocrine and exocrine defects and to advance basic and translational research. © 2021 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.

Dissecting FGF Signalling to Target Cellular Crosstalk in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) has a poor prognosis with a 5 year survival rate of less than 8%, and is predicted to become the second leading cause of cancer-related death by 2030. Alongside late detection, which impacts upon surgical treatment, PDAC tumours are challenging to treat due to their desmoplastic stroma and hypovascular nature, which limits the effectiveness of chemotherapy and radiotherapy. Pancreatic stellate cells (PSCs), which form a key part of this stroma, become activated in response to tumour development, entering into cross-talk with cancer cells to induce tumour cell proliferation and invasion, leading to metastatic spread. We and others have shown that Fibroblast Growth Factor Receptor (FGFR) signalling can play a critical role in the interactions between PDAC cells and the tumour microenvironment, but it is clear that the FGFR signalling pathway is not acting in isolation. Here we describe our current understanding of the mechanisms by which FGFR signalling contributes to PDAC progression, focusing on its interaction with other pathways in signalling networks and discussing the therapeutic approaches that are being developed to try and improve prognosis for this terrible disease.

The matrix in cancer

The extracellular matrix is a fundamental, core component of all tissues and organs, and is essential for the existence of multicellular organisms. From the earliest stages of organism development until death, it regulates and fine-tunes every cellular process in the body. In cancer, the extracellular matrix is altered at the biochemical, biomechanical, architectural and topographical levels, and recent years have seen an exponential increase in the study and recognition of the importance of the matrix in solid tumours. Coupled with the advancement of new technologies to study various elements of the matrix and cell-matrix interactions, we are also beginning to see the deployment of matrix-centric, stromal targeting cancer therapies. This Review touches on many of the facets of matrix biology in solid cancers, including breast, pancreatic and lung cancer, with the aim of highlighting some of the emerging interactions of the matrix and influences that the matrix has on tumour onset, progression and metastatic dissemination, before summarizing the ongoing work in the field aimed at developing therapies to co-target the matrix in cancer and cancer metastasis.

Possibility for Transcriptional Targeting of Cancer-Associated Fibroblasts-Limitations and Opportunities

Cancer-associated fibroblasts (CAF) are attractive therapeutic targets in the tumor microenvironment. The possibility of using CAFs as a source of therapeutic molecules is a challenging approach in gene therapy. This requires transcriptional targeting of transgene expression by cis-regulatory elements (CRE). Little is known about which CREs can provide selective transgene expression in CAFs. We hypothesized that the promoters of FAP, CXCL12, IGFBP2, CTGF, JAG1, SNAI1, and SPARC genes, the expression of whose is increased in CAFs, could be used for transcriptional targeting. Analysis of the transcription of the corresponding genes revealed that unique transcription in model CAFs was characteristic for the CXCL12 and FAP genes. However, none of the promoters in luciferase reporter constructs show selective activity in these fibroblasts. The CTGF, IGFBP2, JAG1, and SPARC promoters can provide higher transgene expression in fibroblasts than in cancer cells, but the nonspecific viral promoters CMV, SV40, and the recently studied universal PCNA promoter have the same features. The patterns of changes in activity of various promoters relative to each other observed for human cell lines were similar to the patterns of activity for the same promoters both in vivo and in vitro in mouse models. Our results reveal restrictions and features for CAF transcriptional targeting.

The Role of Vascular Cells in Pancreatic Beta-Cell Function

Insulin-producing β-cells constitute the majority of the cells in the pancreatic islets. Dysfunction of these cells is a key factor in the loss of glucose regulation that characterizes type 2 diabetes. The regulation of many of the functions of β-cells relies on their close interaction with the intra-islet microvasculature, comprised of endothelial cells and pericytes. In addition to providing islet blood supply, cells of the islet vasculature directly regulate β-cell activity through the secretion of growth factors and other molecules. These factors come from capillary mural pericytes and endothelial cells, and have been shown to promote insulin gene expression, insulin secretion, and β-cell proliferation. This review focuses on the intimate crosstalk of the vascular cells and β-cells and its role in glucose homeostasis and diabetes.

The potential roles of exosomes in pancreatic cancer initiation and metastasis

Pancreatic cancer (PaCa) is an insidious and highly metastatic malignancy, with a 5-year survival rate of less than 5%. So far, the pathogenesis and progression mechanisms of PaCa have been poorly characterized. Exosomes correspond to a class of extracellular nanovesicles, produced by a broad range of human somatic and cancerous cells. These particular nanovesicles are mainly composed by proteins, genetic substances and lipids, which mediate signal transduction and material transport. A large number of studies have indicated that exosomes may play decisive roles in the occurrence and metastatic progression of PaCa. This article summarizes the specific functions of exosomes and their underlying molecular mechanisms in mediating the initiation and metastatic capability of PaCa.

Glomerular Expression of Some Profibrotic Factors in Progressive Childhood Lupus Nephritis

BACKGROUND

Lupus nephritis (LN) is a major cause of mortality and morbidity in both adult and pediatric patients. However, studies regarding pathogenesis and predictors of renal outcomes in childhood LN are limited. Transforming growth factor-β1 (TGF-β1) and Connective tissue growth factor (CTGF) have an important role in proliferative and fibrotic changes in many renal diseases. We aim to evaluate the role of such two profibrotic factors in the progression of childhood onset LN and to detect if their glomerular expression could represent an early predictor of future deterioration of renal function.

METHODS

34 children with new onset of LN were included. Glomerular expressions of TGF-β1 and CTGF were evaluated by immunohistochemical analysis in the renal tissue of such patients and in control tissue. GFR was estimated at time of renal biopsy at the onset of LN and after 2 years of follow-up. Rate of GFR change (ΔGFR) was calculated and used as indicative of degree of renal disease progression.

RESULTS

Glomerular TGF-β1 and CTGF expressions in children with LN were significantly higher than in control tissue (LN 15.41 ± 9.84 and 15.56 ± 10.51 vs. 2.15 ± 1.45 and 1.35 ± 1.07 in control respectively, with p < 0.001 in both). In addition, the glomerular expressions of TGF-β1 and CTGF were significantly higher in patients with further decline in GFR (20.68 ± 7.73 and 21.05 ± 8.75) versus (5.75 ± 4.37 and 5.50 ± 3.78) in those without change in GFR with (p = 0.000 for both of them).

CONCLUSIONS

Patients with LN have increased glomerular expressions of TGF-β1 and CTGF, which were higher in those with further decline in GFR. These profibrotic factors are suspected to be involved in pathogenesis of LN and could be evaluated as a target for therapeutic intervention to stop progression of LN. In addition, their glomerular expression could be used as an early predictor of progression of LN, to justify early aggressive therapy in those with suspected rapid progression.

Pancreatic Ductal Deletion of Hnf1b Disrupts Exocrine Homeostasis, Leads to Pancreatitis, and Facilitates Tumorigenesis

BACKGROUND & AIMS

The exocrine pancreas consists of acinar cells that produce digestive enzymes transported to the intestine through a branched ductal epithelium. Chronic pancreatitis is characterized by progressive inflammation, fibrosis, and loss of acinar tissue. These changes of the exocrine tissue are risk factors for pancreatic cancer. The cause of chronic pancreatitis cannot be identified in one quarter of patients. Here, we investigated how duct dysfunction could contribute to pancreatitis development.

METHODS

The transcription factor Hnf1b, first expressed in pancreatic progenitors, is strictly restricted to ductal cells from late embryogenesis. We previously showed that Hnf1b is crucial for pancreas morphogenesis but its postnatal role still remains unelucidated. To investigate the role of pancreatic ducts in exocrine homeostasis, we inactivated the Hnf1b gene in vivo in mouse ductal cells.

RESULTS

We uncovered that postnatal Hnf1b inactivation in pancreatic ducts leads to chronic pancreatitis in adults. Hnf1bΔ^duct mutants show dilatation of ducts, loss of acinar cells, acinar-to-ductal metaplasia, and lipomatosis. We deciphered the early events involved, with down-regulation of cystic disease-associated genes, loss of primary cilia, up-regulation of signaling pathways, especially the Yap pathway, which is involved in acinar-to-ductal metaplasia. Remarkably, Hnf1bΔ^duct mutants developed pancreatic intraepithelial neoplasia and promote pancreatic intraepithelial neoplasia progression in concert with KRAS. We further showed that adult Hnf1b inactivation in pancreatic ducts is associated with impaired regeneration after injury, with persistent metaplasia and initiation of neoplasia.

CONCLUSIONS

Loss of Hnf1b in ductal cells leads to chronic pancreatitis and neoplasia. This study shows that Hnf1b deficiency may contribute to diseases of the exocrine pancreas and gains further insight into the etiology of pancreatitis and tumorigenesis.

Targeting Pancreatic Stellate Cells in Cancer

Pancreatic stellate cells (PSCs) are the major contributor to the aggressive, metastatic, and resilient nature of pancreatic ductal adenocarcinoma (PDAC), which has a poor prognosis with a 5-year survival rate of 8%. PSCs constitute more than 50% of the tumor stroma in PDAC, where they induce extensive desmoplasia by secreting abundant extracellular matrix (ECM) proteins. In addition, they establish dynamic crosstalk with cancer cells and other stromal cells, which collectively supports tumor progression via various inter- and intracellular pathways. These cellular interactions and associated pathways may reveal novel therapeutic opportunities against this unmet clinical problem. In this review article, we discuss the role of PSCs in inducing tumor progression, their crosstalk with other cells, and therapeutic strategies to target PSCs.

Pharmacotherapeutic strategies for treating pancreatic cancer: advances and challenges

INTRODUCTION

Despite many efforts to improve the outcome of pancreatic ductal adenocarcinoma (PDAC), its prognosis remains poor, which is mostly related to late diagnosis and drug resistance. Improving systemic therapy is considered the major challenge in improving the outcome of this disease.

AREAS COVERED

This review covers novel chemotherapy and targeted agents in the treatment of PDAC, with a focus on advanced stage disease.

EXPERT OPINION

Current frontline therapies used in the treatment of patients with PDAC with favorable performance status are gemcitabine (GEM) and nab-paclitaxel or 5-fluorouracil, leucovorin, irinotecan, and oxaliplatin (FOLFIRINOX). PDAC has a number of genetic mutations that may explain its biological behavior, such as KRAS, p53 and CDK2NA, which occur in more than 90% of cases. Unfortunately, to this day, a specific targeting agent to any of those frequent gene mutations is lacking. Emerging areas of targeted therapies include the DNA repair, stroma, metabolism, and stem cells. Immunotherapy with either vaccines or immune checkpoint inhibitors has not produced any significant improvements in outcome of PDAC. Incorporating different approaches in therapy, including conventional, immunological, and others, is key in offering patients with the best possible care.

Effect of octreotide on pancreatic fibrosis in rats with high-fat diet-induced obesity

BACKGROUND/AIMS

To explore the effect of octreotide on pancreatic fibrosis induced by high-fat diet (HFD) and its mechanism of action.

METHODS

Sprague-Dawley (SD) rats were assigned to control, HFD, or octreotide treatment groups. Glucose and insulin tolerance tests (GTT and ITT), fasting plasma glucose (FPG), and fasting insulin (FINS), serum and pancreatic lipid levels, were measured, and the Lee's index and the homeostatic model assessment (HOMA) index were calculated. The expression levels of alpha-smooth muscle actin (α-SMA), desmin, connective tissue growth factor (CTGF), transforming growth factor beta1 (TGF-β1), Smad3, and Smad7 in the pancreas were quantified. The LTC-14 cell line, which has features of primary rat pancreatic stellate cells (PSCs), was used for in vitro studies.

RESULTS

The AUC of ipGTT and ipITT, and FPG, FINS, lipid levels, were elevated after HFD feeding; however, they decreased after octreotide administration. The expression of α-SMA, CTGF, TGF-β1, and Smad3 in the HFD group were increased relative to the control group, but Smad7 expression was decreased. After treatment with octreotide, α-SMA, CTGF, TGF-β1, and Smad3 expression decreased, whereas the expression of Smad7 increased. In vitro studies showed that the expression of CTGF, TGF-β1, and Smad3 increased with palmitate treatment (PA), which mimics HFD treatment; and octreotide treatment decreased the expression of these proteins. The α-SMA and Smad7 expression levels remained unchanged among the three groups.

CONCLUSIONS

Octreotide can ameliorate pancreatic fibrosis and improve pancreatic beta-cell function induced in HFD treated rats, possibly by inhibiting PSC activation and by decreasing pancreatic extracellular matrix (ECM) through the TGF-β1/Smad signaling pathway.

The critical roles of activated stellate cells-mediated paracrine signaling, metabolism and onco-immunology in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal malignant diseases worldwide. It is refractory to conventional treatments, and consequently has a documented 5-year survival rate as low as 7%. Increasing evidence indicates that activated pancreatic stellate cells (PSCs), one of the stromal components in tumor microenvironment (TME), play a crucial part in the desmoplasia, carcinogenesis, aggressiveness, metastasis associated with PDAC. Despite the current understanding of PSCs as a "partner in crime" to PDAC, detailed regulatory roles of PSCs and related microenvironment remain obscure. In addition to multiple paracrine signaling pathways, recent research has confirmed that PSCs-mediated tumor microenvironment may influence behaviors of PDAC via diverse mechanisms, such as rewiring metabolic networks, suppressing immune responses. These new activities are closely linked with treatment and prognosis of PDAC. In this review, we discuss the recent advances regarding new functions of activated PSCs, including PSCs-cancer cells interaction, mechanisms involved in immunosuppressive regulation, and metabolic reprogramming. It's clear that these updated experimental or clinical studies of PSCs may provide a promising approach for PDAC treatment in the near future.

Regulation and bioactivity of the CCN family of genes and proteins in obesity and diabetes

Across the years the CCNs have been increasingly implicated in the development of obesity, diabetes and its complications. Evidence for this is currently derived from their dysregulation in key metabolic pathological states in humans, animal and in vitro models, and also pre-clinical effects of their bioactivities. CCN2 is the best studied in this disease process and the other CCNs are yet to be better defined. Key steps where CCNs may play a pathogenic metabolic role include: (i) obesity and insulin resistance, where CCN2 inhibits fat cell differentiation in vitro and CCN3 may induce obesity and insulin resistance; (ii) elevated blood glucose levels to diabetes mellitus onset, where CCN2 may contribute to pancreatic beta cell and islet function; and (iii) in diabetes complications, such as nephropathy, retinopathy, liver disease (NAFLD/NASH), CVD and diabetes with heart failure. In contrast, CCN1, CCN2 and possibly CCN3, may have a reparative role in wound healing in diabetes, and CCN2 in islet cell development. In terms of CCN2 regulation by a diabetes metabolic environment and related mechanisms, the author's laboratory and others have progressively shown that advanced glycation-end products, protein kinase C isoforms, saturated fatty acids, reactive oxygen species and haemodynamic factors upregulate CCN2 in relevant cell and animal systems. Recent data has suggested that CCN2, CCN3 and CCN6 may affect energy homeostasis including in regulating glycolysis and mitochondrial function. This paper will address the current data implicating CCNs in diabetes and its complications, focusing on recent aspects with translational clinical relevance and future directions.

An early history of CCN2/CTGF research: the road to CCN2 via hcs24, ctgf, ecogenin, and regenerin

The principal aim of this historical review is to present the processes by which the different aspects of CCN2/CTGF/Hcs24 were discovered by different groups and how much CCN2/CTGF, by being integrated into CCN family, has contributed to the establishment of the basic concepts regarding the role and functions of this new class of proteins. This review should be particularly useful to new investigators who have recently entered this exciting field of study and also provides a good opportunity to acknowledge the input of those individuals who participated in the development of this scientific field.

Identification of target gene of venous thromboembolism in patients with lymphoma via microarray analysis

Patients with lymphoma are at high risk of developing venous thromboembolism (VTE). The purpose of the present study was to identify the target gene associated with VTE for patients with lymphoma. Microarray data was downloaded from the gene expression omnibus database (GSE17078), which comprised the control group, 27 normal blood outgrowth endothelial cell (BOEC) samples, and the case group, 3 BOEC samples of venous thrombosis with protein C deficiency. Differentially expressed genes (DEGs) were identified by the Limma package of R. Gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) pathway analyses were performed via the database for annotation, visualization and integrated discovery. Differentially coexpressed pairs were identified by the DCGL package of R. The subsequent protein-protein interaction (PPI) networks and gene coexpression networks were constructed by the Search Tool for the Retrieval of Interacting Genes/Proteins database, and were visualized by Cytoscape software. A total of 110 DEGs were obtained, including 73 upregulated and 37 downregulated genes. GO and KEGG pathway enrichment analyses identified 132 significant GO terms and 9 significant KEGG pathways. In total, 97 PPI pairs for PPI network and 309 differential coexpression pairs for the gene coexpression network were obtained. Additionally, the connective tissue growth factor (CTGF) gene was closely connected with other genes in the two networks. A total of 2 KEGG pathways were associated with VTE and CTGF may be the target gene of VTE in patients with lymphoma. The present study may identify the molecular mechanism of VTE, but additional clinical study is required to validate the results.

The pro-fibrotic connective tissue growth factor (CTGF/CCN2) correlates with the number of necrotic-regenerative foci in dystrophic muscle

Connective tissue growth factor (CTGF/CCN2) has strong inflammatory and profibrotic activities. Its expression is enhanced in skeletal muscular dystrophies such as Duchenne muscular dystrophy (DMD), a myopathy characterized by exacerbated inflammation and fibrosis. In dystrophic tissue, necrotic-regenerative foci, myofibroblasts, newly-regenerated muscle fibers and necrosis all occur simultaneously. To determine if CCN2 is involved in the appearance of the foci, we studied their presence and characteristics in mdx mice (DMD mouse model) compared to mdx mice hemizygous for CCN2 (mdx-Ccn2+/-). We used laser capture microdissection followed by gene expression and immunofluorescence analyses to investigate fibrotic, inflammation and regeneration markers in damaged and non-damaged areas in mdx and mdx-Ccn2+/- skeletal muscle. Mdx mice foci express elevated mRNAs levels of transforming growth factor type beta, collagen, fibronectin, the myofribroblast marker α-SMA, and the myogenic transcription factor myogenin. Mdx foci also show elevated levels of MCP-1 and CD-68 positive cells, indicating that CCN2 could be inducing an inflammatory response. We found a significant reduction in the number of foci in mdx-Ccn2+/- mice muscle. Fibrotic and inflammatory markers were also decreased in these foci. We did not observe any difference in Pax7 mRNA levels, a marker for satellite cells, in mdx mice compared to mdx-Ccn2+/- mice. Thus, CCN2 appears to be involved in the fibrotic response as well as in the inflammatory response in the dystrophic skeletal muscle.

Role of CCN5 (WNT1 inducible signaling pathway protein 2) in pancreatic islets

In search of direct targets of insulin-like growth factor (IGF)-1 action, we discovered CCN5 (WNT1 inducible signaling pathway protein 2 [WISP2]) as a novel protein expressed in pancreatic β-cells. As a member of the "CCN" ( C ysteine-rich angiogenic inducer 61 [Cyr61], C onnective tissue growth factor [CTGF in humans], and N ephroblastoma overexpressed [Nov; in chickens]) family, the expression of CCN5/WISP2 is stimulated by IGF-1 together with Wnt signaling. When overexpressed in insulinoma cells, CCN5 promotes cell proliferation and cell survival against streptozotocin-induced cell death. The cell proliferation effect seems to be caused by AKT phosphorylation and increased cyclin D1 levels. These properties resemble those of CCN2/CTGF, another isoform of the CCN family, although CCN5 is the only one within the family of six proteins that lacks the C-terminal repeat. Treatment of primary mouse islets with recombinant CCN5 protein produced similar effects to those of gene transfection, indicating that either as a matricellular protein or a secreted growth factor, CCN5 stimulates β-cell proliferation and regeneration in a paracrine fashion. This review also discusses the regulation of CCN5/WISP2 by estrogen and its involvement in angiogenesis and tumorigenesis.

Mesenchymal stem cell-derived CCN2 promotes the proliferation, migration and invasion of human tongue squamous cell carcinoma cells

Recent studies have demonstrated that mesenchymal stem cells (MSC) exhibit a tropism to tumors and form the tumor stroma. In addition, we found that MSC can secrete different types of factors. However, the involvement of MSC‐derived factors in human tongue squamous cell carcinoma (TSCC) growth has not been clearly addressed. The CCN family includes multifunctional signaling molecules that affect the initiation and development events of various tumors. In our study, we report that CCN2/connective tissue growth factor (CTGF) was the most highly induced among the CCN family members in MSC that were co‐cultured with TSCC cells. To evaluate the relationship between CCN2 and TSCC growth, we downregulated MSC‐derived CCN2 expression with shRNA targeting CCN2 and found that MSC‐secreted CCN2 promotes TSCC cell proliferation, migration and invasion. We also confirmed that MSC‐derived CCN2 partially accelerated tumor growth in vitro. Taken together, these results suggest that MSC‐derived CCN2 contributes to the promotion of proliferation, migration and invasion of TSCC cells and may be a possible therapy target in the future.

miR-18a counteracts AKT and ERK activation to inhibit the proliferation of pancreatic progenitor cells

Activation of endogenous stem/progenitor cells to repair injured tissues is an ideal option for disease treatment. However, adult pancreatic progenitor cells remain in a quiescent state in vivo. Thus, it is difficult to stimulate proliferation and differentiation in these progenitor cells, and the cause remains elusive. miR-17-92 cluster miRNAs are highly conserved in mammals and are expressed in multiple tissue stem/progenitor cells, but their role in pancreatic progenitor cells are less well known. In the present study, we demonstrate that miR-18a, but not the other members of the miR-17-92 gene cluster, inhibits the proliferation of pancreatic progenitor cells in vitro and ex vivo. miR-18a inhibits proliferation of adult pancreatic progenitor cells through arresting the cell cycle at G1 stage, indicating that miR-18a plays a role in keeping the adult pancreatic progenitor cells in quiescence. miR-18a inhibits pancreatic progenitor proliferation by targeting the gene expressions of connective tissue growth factor (CTGF), neural precursor cell expressed, developmentally down-regulated 9 (Nedd9), and cyclin dependent kinase 19 (CDK19), as well as by suppressing activation of the proliferation-related signaling pathways phosphatidylinositol 3-kinase–protein kinase B (PI3K/AKT) and extracellular signal-regulated kinase (ERK).

Pancreatic cancer: Stroma and its current and emerging targeted therapies

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal human malignancies with a 5-year survival rate of 8%. Dense, fibrotic stroma associated with pancreatic tumors is a major obstacle for drug delivery to the tumor bed and plays a crucial role in pancreatic cancer progression. Targeting stroma is considered as a potential therapeutic strategy to improve anti-cancer drug efficacy and patient survival. Although numerous stromal depletion therapies have reached the clinic, they add little to overall survival and are often associated with toxicity. Furthermore, increasing evidence suggests the anti-tumor properties of stroma. Its complete ablation enhanced tumor progression and reduced survival. Consequently, efforts are now focused on developing stromal-targeted therapies that normalize the reactive stroma and avoid the extremes: stromal abundance vs. complete depletion. In this review, we summarized the state of current and emerging anti-stromal targeted therapies, with major emphasis on the role of miRNAs in PDAC stroma and their potential use as novel therapeutic agents to modulate PDAC tumor-stromal interactions.

The CCN family of proteins: a 25th anniversary picture

The CCN family of proteins is composed of six members, which are now well recognized as major players in fundamental biological processes. The first three CCN proteins discovered were designated CYR61, CTGF, and NOV because of the context in which they were identified. Both CYR61 and CTGF were discovered in normal cells, whereas NOV was identified in tumors. Soon after their discovery, it was established that they shared important and unique structural features and distinct biological properties. Based on these structural considerations, the three proteins were proposed to belong to a family that was designated CCN by P. Bork. Hence the CCN1, CCN2 and CCN3 acronyms. The family grew to six members a few years later with the description of three proteins WISP-1, WISP-2 and WISP-3 (CCN4, CCN5 and CCN6), that shared the same tetramodular and conserved structural features. With the functions of the CCN proteins being uncovered, this raised a nomenclature problem. A scientific committee convened in Saint Malo (France) proposed to apply the CCN nomenclature to the six members of the family. Although the unified nomenclature was proposed in order to avoid serious misconceptions and lack of precision associated with the use of the old acronyms, the acceptance of the new acronyms has taken time. In order to evaluate how the use of disparate nomenclatures have had an impact on the CCN protein field, we conducted a survey of the articles that have been published in this area since the discovery of the first CCN proteins and inception of the field. We report in this manuscript the confusion and serious deleterious scientific consequences that have stemmed from a disorganized usage of several unrelated acronyms. The conclusions that we have reached call for a unification that needs to overcome personal habits and feelings. Instead of allowing the CCN field to fully crystalize and gain the recognition that it deserves the usage of many different acronyms represents a danger that everyone must fight against in order to avoid its deliquescence. We hope that the considerations discussed in the present article will encourage all authors working in the CCN field to work jointly and succeed in building a strong and coherent CCN scientific community that will benefit all of us.

Human pancreatic cancer progression: an anarchy among CCN-siblings

Decades of basic and translational studies have identified the mechanisms by which pancreatic cancer cells use molecular pathways to hijack the normal homeostasis of the pancreas, promoting pancreatic cancer initiation, progression, and metastasis, as well as drug resistance. These molecular pathways were explored to develop targeted therapies to prevent or cure this fatal disease. Regrettably, the studies found that majority of the molecular events that dictate carcinogenic growth in the pancreas are non-actionable (potential non-responder groups of targeted therapy). In this review we discuss exciting discoveries on CCN-siblings that reveal how CCN-family members contribute to the different aspects of the development of pancreatic cancer with special emphasis on therapy.

Role of CCN2 in Amino Acid Metabolism of Chondrocytes

CCN2/connective tissue growth factor (CTGF) is a multi-functional molecule that promotes harmonized development and regeneration of cartilage through its matricellular interaction with a variety of extracellular biomolecules. Thus, deficiency in CCN2 supply profoundly affects a variety of cellular activities including basic metabolism. A previous study showed that the expression of a number of ribosomal protein genes was markedly enhanced in Ccn2-null chondrocytes. Therefore, in this study, we analyzed the impact of CCN2 on amino acid and protein metabolism in chondrocytes. Comparative metabolome analysis of the amino acids in Ccn2-null and wild-type mouse chondrocytes revealed stable decreases in the cellular levels of all of the essential amino acids. Unexpectedly, uptake of such amino acids was rather enhanced in Ccn2-null chondrocytes, and the addition of exogenous CCN2 to human chondrocytic cells resulted in decreased amino acid uptake. However, as expected, amino acid consumption by protein synthesis was also accelerated in Ccn2-null chondrocytes. Furthermore, we newly found that expression of two genes encoding two glycolytic enzymes, as well as the previously reported Eno1 gene, was repressed in those cells. Considering the impaired glycolysis and retained mitochondrial membrane potential in Ccn2-null chondrocytes, these findings suggest that Ccn2 deficiency induces amino acid shortage in chondrocytes by accelerated amino acid consumption through protein synthesis and acquisition of aerobic energy. Interestingly, CCN2 was found to capture such free amino acids in vitro. Under physiological conditions, CCN2 may be regulating the levels of free amino acids in the extracellular matrix of cartilage.

Blockade of CCN4 attenuates CCl4-induced liver fibrosis

INTRODUCTION

CCN4, also termed WNT-inducible signaling pathway protein-1 (WISP-1), has important roles in inflammation and tissue injury. This study aimed to investigate the effect of CCN4 inhibition using monoclonal anti-CCN4 antibody (CCN4mAb) on the liver injury and fibrosis in a mouse model of liver fibrosis.

MATERIAL AND METHODS

The mouse liver fibrosis model was induced by carbon tetrachloride (CCl4). Mice received vehicle (saline/olive oil) by subcutaneous injection, CCl4 by subcutaneous injection or CCl4 (subcutaneous) plus CCN4mAb by subcutaneous injection. The pro-inflammatory and pro-fibrotic factors were determined by Western blot. The biochemistry and histopathology, collagen deposition and nuclear factor (NF)-κB activity were also assessed.

RESULTS

Chronic CCl4 treatment caused liver injury and collagen accumulation. The expression levels of CCN4, pro-inflammatory and pro-fibrotic mediators as well as the activity of NF-κB were markedly increased. Treatment with CCN4mAb significantly inhibited CCl4-induced CCN4 expression, leading to attenuated CCl4-induced liver injury and the inflammatory response. CCN4 blockade also significantly reduced the formation of collagen in the liver and the expression of α-smooth muscle actin and transforming growth factor β1.

CONCLUSIONS

CCN4 inhibition by CCN4mAb in vivo significantly attenuated the CCl4-induced liver injury and the progression of liver fibrosis. CCN4 may represent a novel therapeutic target for liver injury and fibrosis.

Connective tissue growth factor modulates adult β-cell maturity and proliferation to promote β-cell regeneration in mice

Stimulation of endogenous β-cell expansion could facilitate regeneration in patients with diabetes. In mice, connective tissue growth factor (CTGF) is expressed in embryonic β-cells and in adult β-cells during periods of expansion. We discovered that in embryos CTGF is necessary for β-cell proliferation, and increased CTGF in β-cells promotes proliferation of immature (MafA(-)) insulin-positive cells. CTGF overexpression, under nonstimulatory conditions, does not increase adult β-cell proliferation. In this study, we tested the ability of CTGF to promote β-cell proliferation and regeneration after partial β-cell destruction. β-Cell mass reaches 50% recovery after 4 weeks of CTGF treatment, primarily via increased β-cell proliferation, which is enhanced as early as 2 days of treatment. CTGF treatment increases the number of immature β-cells but promotes proliferation of both mature and immature β-cells. A shortened β-cell replication refractory period is also observed. CTGF treatment upregulates positive cell-cycle regulators and factors involved in β-cell proliferation, including hepatocyte growth factor, serotonin synthesis, and integrin β1. Ex vivo treatment of whole islets with recombinant human CTGF induces β-cell replication and gene expression changes consistent with those observed in vivo, demonstrating that CTGF acts directly on islets to promote β-cell replication. Thus, CTGF can induce replication of adult mouse β-cells given a permissive microenvironment.

Arrested development and the great escape--the role of cellular senescence in pancreatic cancer

The outcomes of pancreatic cancer remain dismal due to late clinical presentation and the aggressive nature of the disease. A heterogeneous combination of genetic mutations, including KRAS, INK4a/CDKN2A and p53, underpin the propensity of pancreatic cancer to rapidly invade and disseminate. These oncogenes and tumour suppressors are strongly associated with cellular senescence, therefore suggesting this process as having a key role in malignant transformation. In the context of cancer, oncogenic stimuli trigger the senescent phenotype resulting in cell cycle growth arrest and prevention of progression of premalignant lesions such as PanINs. However mutations of the aforementioned oncogenes or tumour suppressors result in cells escaping senescence and thus allowing tumours to progress. This review presents current evidence regarding both senescence induction and escape with respect to pancreatic cancer, highlighting the key roles of p19ARF, p53, Rb and P16INK4a. The epigenetic regulatory component is also discussed, with relevance to DNA methylation and HDACs. Lastly the role of the tumour microenvironment, and in particular pancreatic stellate cells, is discussed with regards to the induction of a senescence associated secretory phenotype (SASP), with SASP-associated secretory factors contributing to the pro-tumorigenic effects of the surrounding activated stroma. Further work is required in this field to elucidate the most important pathways relating to cellular senescence that contribute to the belligerent nature of this disease, with the aim of discovering therapeutic targets to improve patient outcomes.

Cellular and molecular actions of CCN2/CTGF and its role under physiological and pathological conditions

CCN family protein 2 (CCN2), also widely known as connective tissue growth factor (CTGF), is one of the founding members of the CCN family of matricellular proteins. Extensive investigation on CCN2 over decades has revealed the novel molecular action and functional properties of this unique signalling modulator. By its interaction with multiple molecular counterparts, CCN2 yields highly diverse and context-dependent biological outcomes in a variety of microenvironments. Nowadays, CCN2 is recognized to conduct the harmonized development of relevant tissues, such as cartilage and bone, in the skeletal system, by manipulating extracellular signalling molecules involved therein by acting as a hub through a web. However, on the other hand, CCN2 occasionally plays profound roles in major human biological disorders, including fibrosis and malignancies in major organs and tissues, by modulating the actions of key molecules involved in these clinical entities. In this review, the physiological and pathological roles of this unique protein are comprehensively summarized from a molecular network-based viewpoint of CCN2 functionalities.

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.