Specific protein and miRNA patterns characterise tumour-associated fibroblasts in bladder cancer

MiR-20a-5p Negatively Regulates NR4A3 to Promote Metastasis in Bladder Cancer

Metastasis is the leading cause of death in cancer patients. Therefore, the prediction and treatment of metastasis are critical in improving the survival of patients with bladder cancer. In this study, we aimed to investigate the role of miR-20a-5p and NR4A3 in bladder cancer and the regulatory relationship between them. The high expression of miR-20a-5p in the bladder cancer (BCa) tissues and cells was determined by qRT-PCR. Exogenous miR-20a-5p overexpression promoted the proliferation, migration, and invasion of BCa cells. MiR-20a-5p inhibition inhibited the BCa cell proliferation, invasion, and migration. NR4A3 was proved to be the target gene of miR-20a-5p by the double luciferase reporter assay. In addition, the reduction of NR4A3 could promote the proliferation, invasion, and clonal formation of the bladder cancer cells 5637 and T24. NR4A3 overexpression could reverse the carcinogenic effect of miR-20a. We further confirmed that the oncogenic effect of miR-20a was achieved by promoting EMT in tumor cells. MiR-20a-5p promoted the growth and metastasis of the bladder cancer cells by inhibiting the expression of the tumor suppressor gene NR4A3 and played a carcinogenic role in BCa. Thus, miR-20a-5p may become a potential therapeutic target for BCa treatment.

Fundamental and Clinical Applications of Materials Based on Cancer-Associated Fibroblasts in Cancers

Cancer stromal cells play a role in promoting tumor relapse and therapeutic resistance. Therefore, the current treatment paradigms for cancers are usually insufficient to eradicate cancer cells, and anti-cancer therapeutic strategies targeting stromal cells have been developed. Cancer-associated fibroblasts (CAFs) are perpetually activated fibroblasts in the tumor stroma. CAFs are the most abundant and highly heterogeneous stromal cells, and they are critically involved in cancer occurrence and progression. These effects are due to their various roles in the remodeling of the extracellular matrix, maintenance of cancer stemness, modulation of tumor metabolism, and promotion of therapy resistance. Recently, biomaterials and nanomaterials based on CAFs have been increasingly developed to perform gene or protein expression analysis, three-dimensional (3D) co-cultivation, and targeted drug delivery in cancer treatment. In this review, we systematically summarize the current research to fully understand the relevant materials and their functional diversity in CAFs, and we highlight the potential clinical applications of CAFs-oriented biomaterials and nanomaterials in anti-cancer therapy.

The prognostic value of cytokeratin and extracellular collagen expression in urinary bladder cancer

BACKGROUND

Expression levels of collagens have been implicated in the progression of various cancers and interact with cytokeratins, but are not well studied in bladder cancer (BC). Therefore, we analyzed the gene and protein expression levels of collagen 1A1 (Col1a1/COL1A1), collagen 3A1 (col3a1/COL3A1), collagen 5A2 (col5a2/COL5A2), cytokeratin 14 (krt14/CK14), and cytokeratin 17 (krt17/CK17) in urothelial BC samples of different stages.

METHODS

In total, 102 fresh frozen and 190 formalin fixed and paraffin embedded (FFPE) samples were tested using immunohistochemistry and RT-qPCR. Expression levels were correlated to clinicopathological and follow-up data.

RESULTS

Col1a1, col3a1, col5a2 and krt14 mRNA levels were significantly overexpressed in high-grade and muscle-invasive BC (MIBC) compared to low-grade and non-muscle invasive BC (NMIBC) cases. Disease-specific survival (DSS) was shorter in patients with high expression levels of col1a1 (p = 0.004), col3a1 (p = 0.004), and col5a2 (p = 0.028). CK14 (p = 0.020), COL3A1 (p = 0.006) and Col5A2 (p = 0.006) protein expression levels were significantly higher and protein expression levels of CK17 (p = 0.05) significantly lower in MIBC compared to NMIBC. Furthermore, CK14 (p = 0.002) and COL5A2 (p = 0.006) protein expressions were significantly higher in high-grade compared to low-grade BC. DSS was shorter in patients with high expression levels of COL5A2 (p = 0.033) and CK14 (p = 0.042).

CONCLUSION

Expression changes of collagens and cytokeratins are univariable prognostic markers in BC.

Metabolic Reprogramming of Fibroblasts as Therapeutic Target in Rheumatoid Arthritis and Cancer: Deciphering Key Mechanisms Using Computational Systems Biology Approaches

Fibroblasts, the most abundant cells in the connective tissue, are key modulators of the extracellular matrix (ECM) composition. These spindle-shaped cells are capable of synthesizing various extracellular matrix proteins and collagen. They also provide the structural framework (stroma) for tissues and play a pivotal role in the wound healing process. While they are maintainers of the ECM turnover and regulate several physiological processes, they can also undergo transformations responding to certain stimuli and display aggressive phenotypes that contribute to disease pathophysiology. In this review, we focus on the metabolic pathways of glucose and highlight metabolic reprogramming as a critical event that contributes to the transition of fibroblasts from quiescent to activated and aggressive cells. We also cover the emerging evidence that allows us to draw parallels between fibroblasts in autoimmune disorders and more specifically in rheumatoid arthritis and cancer. We link the metabolic changes of fibroblasts to the toxic environment created by the disease condition and discuss how targeting of metabolic reprogramming could be employed in the treatment of such diseases. Lastly, we discuss Systems Biology approaches, and more specifically, computational modeling, as a means to elucidate pathogenetic mechanisms and accelerate the identification of novel therapeutic targets.

Recent trends in targeting miRNAs for cancer therapy

OBJECTIVES

MicroRNAs (miRNAs) are a type of small noncoding RNA employed by the cells for gene regulation. A single miRNA, typically 22 nucleotides in length, can regulate the expression of numerous genes. Over the past decade, the study of miRNA biology in the context of cancer has led to the development of new diagnostic and therapeutic opportunities.

KEY FINDINGS

MicroRNA dysregulation is commonly associated with cancer, in part because miRNAs are actively involved in the mechanisms like genomic instabilities, aberrant transcriptional control, altered epigenetic regulation and biogenesis machinery defects. MicroRNAs can regulate oncogenes or tumour suppressor genes and thus when altered can lead to tumorigenesis. Expression profiling of miRNAs has boosted the possibilities of application of miRNAs as potential cancer biomarkers and therapeutic targets, although the feasibility of these approaches will require further validation.

SUMMARY

In this review, we will focus on how miRNAs regulate tumour development and the potential applications of targeting miRNAs for cancer therapy.

Emerging Therapeutic RNAs for the Targeting of Cancer Associated Fibroblasts

Tumor mass consists of a complex ensemble of malignant cancer cells and a wide variety of resident and infiltrating cells, secreted factors, and extracellular matrix proteins that are referred as tumor microenvironment (TME). Cancer associated fibroblasts (CAFs) are key TME components that support tumor growth, generating a physical barrier against drugs and immune infiltration, and contributing to regulate malignant progression. Thus, it is largely accepted that therapeutic approaches aimed at hampering the interactions between tumor cells and CAFs can enhance the effectiveness of anti-cancer treatments. In this view, nucleic acid therapeutics have emerged as promising molecules. Here, we summarize recent knowledge about their role in the regulation of CAF transformation and tumor-promoting functions, highlighting their therapeutic utility and challenges.

Epigenetics of Bladder Cancer: Where Biomarkers and Therapeutic Targets Meet

Bladder cancer (BC) is the most common neoplasia of the urothelial tract. Due to its high incidence, prevalence, recurrence and mortality, it remains an unsolved clinical and social problem. The treatment of BC is challenging and, although immunotherapies have revealed potential benefit in a percentage of patients, it remains mostly an incurable disease at its advanced state. Epigenetic alterations, including aberrant DNA methylation, altered chromatin remodeling and deregulated expression of non-coding RNAs are common events in BC and can be driver events in BC pathogenesis. Accordingly, these epigenetic alterations are now being used as potential biomarkers for these disorders and are being envisioned as potential therapeutic targets for the future management of BC. In this review, we summarize the recent findings in these emerging and exciting new aspects paving the way for future clinical treatment of this disease.

Biological heterogeneity and versatility of cancer-associated fibroblasts in the tumor microenvironment

Increasing lines of evidence show that the malignant behavior of cancer is not exclusively attributable to cancer cells but also radically influenced by cancerous stroma activity and controlled through various mechanisms by the microenvironment. In addition to structural components, such as the extracellular matrix, stromal cells, such as macrophages, endothelial cells, and specifically cancer-associated fibroblasts (CAFs), have attracted substantial attention over recent decades. CAFs provide routes for aggressive carcinomas and contribute to invasion and metastasis through the biochemical alteration and regulation of cancer-related pathways. However, another facet of CAFs that has been neglected by numerous studies is that CAFs might serve as a negative regulator of cancer progression under certain circumstances. The various origins of CAFs, the diverse tissues in which they reside and their interactions with different cancer cells appear to be responsible for this inconsistency. This review summarizes the latest knowledge regarding CAF heterogeneity and offers a novel perspective and a beneficial approach for obtaining an improved understanding of CAFs.

Deregulated MicroRNAs in Cancer-Associated Fibroblasts from Front Tumor Tissues of Lung Adenocarcinoma as Potential Predictors of Tumor Promotion

Cancer-associated fibroblasts (CAFs) are the main component of the tumor stroma and promote tumor progression through several mechanisms. Recent evidence indicates that small noncoding RNAs, microRNAs (miRNAs), play key roles in CAF tumor-promoting properties; however, the role of miRNAs in lung cancer-associated fibroblasts remains poorly defined. We characterized the differential miRNA expression profile of fibroblasts isolated from matched tumor front (F-CAFs), inner tumor (In-CAFs), and normal adjacent (NFs) tissues from four lung adenocarcinoma patients (ADs) using microarray analysis. Proliferation and invasion assays of A549 human lung cancer cells in the presence of conditioned medium from F-CAFs, In-CAFs or NFs were performed to assess tumorigenic properties. Ten identified candidate miRNAs in F-CAFs, In-CAFs and NFs from 12 ADs were then validated by RT-PCR. Both F-CAFs and In-CAFs enhanced the proliferation and invasion of A549 cells compared with NFs; moreover, F-CAFs showed a significantly stronger effect than In-CAFs. RT-PCR validation demonstrated three downregulated miRNAs in F-CAFs compared with NFs (miR-145-3p, miR-299-3p, and miR-505-3p), two in F-CAFs compared with In-CAFs (miR-410-3p and miR-485-5p), but no differentially expressed miRNAs between In-CAFs and NFs. Further target-gene prediction and pathway enrichment analysis indicated that deregulated miRNAs in F-CAFs showed significant associations with "pathways in cancer" (miR-145-3p, miR-299-3p and miR-410-3p), "Wnt signaling pathway" (miR-410-3p and miR-505-3p), and "TGF-beta signaling pathway" (miR-410-3p). Importantly, a tumor-promoting growth factor targeted by those miRNAs, VEGFA, was upregulated in F-CAFs compared with NFs, as judged by RT-PCR. In conclusion, deregulated miRNAs in F-CAFs are potentially associated with CAF tumor-promoting properties.

MiR-411 suppresses the development of bladder cancer by regulating ZnT1

Background

At present, the molecular genetics of the development and progression of bladder cancer are still unclear. In recent years, the pathological relevance and significance of microRNAs (miRNAs) in bladder cancer have attracted increasing attention.

Methods

The expressions of miR-411 and zinc transporter 1 (ZnT1) in bladder cancer were determined by western blot and real-time PCR. Biological software, luciferase reporter gene, Western blot and real-time PCR were used to determine the regulatory effect of miR-411 on ZnT1. MTT and transwell were used to confirm the regulatory effect of miR-411 on bladder cancer cells. MTT and transwell were used to find how miR-411 modulated the biological activity of bladder cancer cells by regulating ZnT1.

Results

The expression of miR-411 was low in bladder cancer and was negatively correlated with ZnT1. MiR-411 can inhibit the activity and the expression of ZnT1. MiR-411 can inhibit the growth and metastasis of bladder cancer cells. MiR-411 inhibited the growth and metastasis of bladder cancer cells by targeting ZnT1.

Conclusion

The miR-411 target ZnT1 may provide a potential therapeutic target for the treatment of bladder cancer.

Epigenetic Crosstalk between the Tumor Microenvironment and Ovarian Cancer Cells: A Therapeutic Road Less Traveled

Metastatic dissemination of epithelial ovarian cancer (EOC) predominantly occurs through direct cell shedding from the primary tumor into the intra-abdominal cavity that is filled with malignant ascitic effusions. Facilitated by the fluid flow, cells distribute throughout the cavity, broadly seed and invade through peritoneal lining, and resume secondary tumor growth in abdominal and pelvic organs. At all steps of this unique metastatic process, cancer cells exist within a multidimensional tumor microenvironment consisting of intraperitoneally residing cancer-reprogramed fibroblasts, adipose, immune, mesenchymal stem, mesothelial, and vascular cells that exert miscellaneous bioactive molecules into malignant ascites and contribute to EOC progression and metastasis via distinct molecular mechanisms and epigenetic dysregulation. This review outlines basic epigenetic mechanisms, including DNA methylation, histone modifications, chromatin remodeling, and non-coding RNA regulators, and summarizes current knowledge on reciprocal interactions between each participant of the EOC cellular milieu and tumor cells in the context of aberrant epigenetic crosstalk. Promising research directions and potential therapeutic strategies that may encompass epigenetic tailoring as a component of complex EOC treatment are discussed.

Human foreskin fibroblasts: from waste bag to important biomedical applications

Circumcision is one of the most performed surgical procedures worldwide, and it is estimated that one in three men worldwide is circumcised, which makes the preputial skin removed after surgery an abundant material for possible applications. In particular, it is possible efficiently to isolate the cells of the foreskin, with fibroblasts being the most abundant cells of the dermis and the most used in biomedical research. This work aimed to review the knowledge and obtain a broad view of the main applications of human foreskin fibroblast cell culture. A literature search was conducted, including clinical trials, preclinical basic research studies, reviews and experimental studies. Several medical and laboratory applications of human foreskin fibroblast cell culture have been described, especially when it comes to the use of human foreskin fibroblasts as feeder cells for the cultivation of human embryonic stem cells, in addition to co-culture with other cell types. The culture of foreskin fibroblasts has also been used to: obtain induced pluripotent stem cells; the diagnosis of Clostridium difficile; to test the toxicity and effect of substances on normal cells, especially the toxicity of possible antineoplastic drugs; in viral culture, mainly of the human cytomegalovirus, study of the pathogenesis of other microorganisms; varied studies of cellular physiology and cellular interactions. Fibroblasts are important for cell models for varied application cultures, demonstrating how the preputial material can be reused, making possible new applications.

Level of evidence: Not applicable for this multicentre audit.

miR-31 affects colorectal cancer cells by inhibiting autophagy in cancer-associated fibroblasts

Autophagy is a double-edged sword in tumor development. Recent studies have found that miRNAs have an inhibitory effect on the regulation of autophagy. It has been reported that miR-31 plays an important role in the development of colorectal cancer. However, what role miR-31 plays in colorectal cancer-associated fibroblasts (CAFs) has not been determined. In this study, we confirmed that the expression of miR-31 in CAFs was higher than in normal colorectal fibroblasts (NFs). We also found that treatment of CAFs with miR-31 mimic inhibited the expression of the autophagy-related genes Beclin-1, ATG, DRAM and LC3. In addition, we found up-regulation of miR-31 significantly affected colorectal cancer cell behaviors, including proliferation, invasion and apoptosis. Also, up-regulation of miR-31 in CAF could increase the radiosensitivity of colorectal cancer cells co-cultured with CAF. In summary, miR-31 can inhibit autophagy in colorectal CAFs, affect colorectal cancer development, and increase the radiosensitivity of colorectal cancer cells co-cultured with CAF. We hypothesize that miR-31 may become a new target of treatments for colorectal cancer.

The microRNA-15a-PAI-2 axis in cholangiocarcinoma-associated fibroblasts promotes migration of cancer cells

BACKGROUND

Cholangiocarcinoma (CCA) has an abundance of tumor stroma which plays an important role in cancer progression via tumor-promoting signals. This study aims to explore the microRNA (miRNA) profile of CCA-associated fibroblasts (CCFs) and the roles of any identified miRNAs in CCA progression.

METHODS

miRNA expression profiles of CCFs and normal skin fibroblasts were compared by microarray. Identified downregulated miRNAs and their target genes were confirmed by real-time PCR. Their binding was confirmed by a luciferase reporter assay. The effects of conditioned-media (CM) of miRNA mimic- and antagonist-transfected CCFs were tested in CCA migration in wound healing assays. Finally, the levels of miRNA and their target genes were examined by real-time PCR and immunohistochemistry in clinical CCA samples.

RESULTS

miR-15a was identified as a downregulated miRNA in CCFs. Moreover, PAI-2 was identified as a novel target gene of miR-15a. Recombinant PAI-2 promoted migration of CCA cells. Moreover, CM from miR-15a mimic-transfected CCFs suppressed migration of CCA cells. Lower expression of miR-15a and higher expression of PAI-2 were observed in human CCA samples compared with normal liver tissues. Importantly, PAI-2 expression correlated with poor prognosis in CCA patients.

CONCLUSIONS

These findings highlight the miR-15a/PAI-2 axis as a potential therapeutic target in CCA patients.

Cancer associated fibroblasts: An essential role in the tumor microenvironment

Fibroblasts in the tumor stroma are well recognized as having an indispensable role in carcinogenesis, including in the initiation of epithelial tumor formation. The association between cancer cells and fibroblasts has been highlighted in several previous studies. Regulation factors released from cancer-associated fibroblasts (CAFs) into the tumor microenvironment have essential roles, including the support of tumor growth, angiogenesis, metastasis and therapy resistance. A mutual interaction between tumor-induced fibroblast activation, and fibroblast-induced tumor proliferation and metastasis occurs, thus CAFs act as tumor supporters. Previous studies have reported that by developing fibroblast-targeting drugs, it may be possible to interrupt the interaction between fibroblasts and the tumor, thus resulting in the suppression of tumor growth, and metastasis. The present review focused on the reciprocal feedback loop between fibroblasts and cancer cells, and evaluated the potential application of anti-CAF agents in the treatment of cancer.

Genetic alterations and epigenetic alterations of cancer-associated fibroblasts

Cancer-associated fibroblasts (CAFs) are one major type of component identified in the tumor microenvironment. Studies have focused on the genetic and epigenetic status of CAFs, since they are critical in tumor progression and differ phenotypically and functionally from normal fibroblasts. The present review summarizes the recent achievements in understanding the gene profiles of CAFs and pays special attention to their possible epigenetic alterations. A total of 7 possible genetic alterations and epigenetic changes in CAFs are discussed, including gene differential expression, karyotype analysis, gene copy number variation, loss of heterozygosis, allelic imbalance, microsatellite instability, post-transcriptional control and DNA methylation. These genetic and epigenetic characteristics are hypothesized to provide a deep understanding of CAFs and a perspective on their clinical significance.

Epithelial plasticity in urothelial carcinoma: Current advancements and future challenges

Urothelial carcinoma (UC) of the bladder is characterized by high recurrence rate where a subset of these cells undergoes transition to deadly muscle invasive disease and later metastasizes. Urothelial cancer stem cells (UroCSCs), a tumor subpopulation derived from transformation of urothelial stem cells, are responsible for heterogeneous tumor formation and resistance to systemic treatment in UC of the bladder. Although the precise reason for pathophysiologic spread of tumor is not clear, transcriptome analysis of microdissected cancer cells expressing multiple progenitor/stem cell markers validates the upregulation of genes that derive epithelial-to-mesenchymal transition. Experimental studies on human bladder cancer xenografts describe the mechanistic functions and regulation of epithelial plasticity for its cancer-restraining effects. It has been further examined to be associated with the recruitment of a pool of UroCSCs into cell division in response to damages induced by adjuvant therapies. This paper also discusses the various probable therapeutic approaches to attenuate the progressive manifestation of chemoresistance by co-administration of inhibitors of epithelial plasticity and chemotherapeutic drugs by abrogating the early tumor repopulation as well as killing differentiated cancer cells.

Epithelial plasticity in urothelial carcinoma: Current advancements and future challenges

Urothelial carcinoma (UC) of the bladder is characterized by high recurrence rate where a subset of these cells undergoes transition to deadly muscle invasive disease and later metastasizes. Urothelial cancer stem cells (UroCSCs), a tumor subpopulation derived from transformation of urothelial stem cells, are responsible for heterogeneous tumor formation and resistance to systemic treatment in UC of the bladder. Although the precise reason for pathophysiologic spread of tumor is not clear, transcriptome analysis of microdissected cancer cells expressing multiple progenitor/stem cell markers validates the upregulation of genes that derive epithelial-to-mesenchymal transition. Experimental studies on human bladder cancer xenografts describe the mechanistic functions and regulation of epithelial plasticity for its cancer-restraining effects. It has been further examined to be associated with the recruitment of a pool of UroCSCs into cell division in response to damages induced by adjuvant therapies. This paper also discusses the various probable therapeutic approaches to attenuate the progressive manifestation of chemoresistance by co-administration of inhibitors of epithelial plasticity and chemotherapeutic drugs by abrogating the early tumor repopulation as well as killing differentiated cancer cells.

[Tumour-stroma interactions in urothelial cancer]

BACKGROUND

The histopathological structure of malignant tumours involves two essential compartments - the tumour parenchyma with the actual transformed cells, and the supportive tumour stroma. The latter consists of specialized mesenchymal cells, such as fibroblasts, macrophages, lymphocytes and vascular cells, as well as of their secreted products, including components of the extracellular matrix, matrix modifying enzymes and numerous regulatory growth factors and cytokines. In consequence, the tumour stroma has the ability to influence virtually all aspects of tumour development and progression, including therapeutic response.

AIM

In this article we review the current knowledge of tumor stroma interactions in urothelial carcinoma and present various experimental systems that are currently in use to unravel the biological basis of these heterotypic cell interactions.

RESULTS

For urothelial carcinoma, an extensive tumour stroma is quite typical and markers of activated fibroblasts correlate significantly with clinical parameters of advanced disease. Another clinically important variable is provided by the stromal expression of syndecan-1.

CONCLUSION

Integration of markers of activated stroma into clinical risk evaluation could aid to better stratification of urothelial bladder carcinoma patients. Elucidation of biological mechanisms underlying tumour-stroma interactions could provide new therapeutical targets.

Involvement of the Androgen and Glucocorticoid Receptors in Bladder Cancer

Bladder cancer is encountered worldwide having been associated with a host of environmental and lifestyle risk factors. The disease has a male to female prevalence of 3 : 1. This disparity has raised the possibility of the androgen receptor (AR) pathway being involved in the genesis of the disease; indeed, research has shown that AR is involved in and is likely a driver of bladder cancer. Similarly, an inflammatory response has been implicated as a major player in bladder carcinogenesis. Consistent with this concept, recent work on anti-inflammatory glucocorticoid signaling points to a pathway that may impact bladder cancer. The glucocorticoid receptor- (GR-) α isoform has an important role in suppressing inflammatory processes, which may be attenuated by AR in the development of bladder cancer. In addition, a GR isoform that is inhibitory to GRα, GRβ, is proinflammatory and has been shown to induce cancer growth. In this paper, we review the evidence of inflammatory mediators and the relationship of AR and GR isoforms as they relate to the propensity for bladder cancer.

Epigenetic silencing of microRNA-149 in cancer-associated fibroblasts mediates prostaglandin E2/interleukin-6 signaling in the tumor microenvironment

Tumor initiation and growth depend on its microenvironment in which cancer-associated fibroblasts (CAFs) in tumor stroma play an important role. Prostaglandin E2 (PGE2) and interleukin (IL)-6 signal pathways are involved in the crosstalk between tumor and stromal cells. However, how PGE2-mediated signaling modulates this crosstalk remains unclear. Here, we show that microRNA (miR)-149 links PGE2 and IL-6 signaling in mediating the crosstalk between tumor cells and CAFs in gastric cancer (GC). miR-149 inhibited fibroblast activation by targeting IL-6 and miR-149 expression was substantially suppressed in the CAFs of GC. miR-149 negatively regulated CAFs and their effect on GC development both in vitro and in vivo. CAFs enhanced epithelial-to-mesenchymal transition (EMT) and the stem-like properties of GC cells in a miR-149-IL-6-dependent manner. In addition to IL-6, PGE2 receptor 2 (PTGER2/EP2) was revealed as another potential target of miR-149 in fibroblasts. Furthermore, H. pylori infection, a leading cause of human GC, was able to induce cyclooxygenase-2 (COX-2)/PGE2 signaling and to enhance PGE2 production, resulting in the hypermethylation of miR-149 in CAFs and increased IL-6 secretion. Our findings indicate that miR-149 mediates the crosstalk between tumor cells and CAFs in GC and highlight the potential of interfering miRNAs in stromal cells to improve cancer therapy.

Malignancy of bladder cancer cells is enhanced by tumor-associated fibroblasts through a multifaceted cytokine-chemokine loop

The microenvironment of tumor cells is critically involved in tumor development and progression. Tumor-associated fibroblasts (TAFs) represent a major constituent of the tumor stroma. Tumor cells are operative in the activation of TAFs, whereas TAFs in turn contribute to tumor cell malignancy. This report describes mechanisms of communication between fibroblasts and urinary bladder cancer (UBC) cells. Migration of bladder cancer cell lines RT112 and Cal-29, representing two different grades of dedifferentiation, was enhanced by cocultivation with TAFs. Conditioned medium from tumor cells induced the release of interleukin (IL)-8, hepatocyte growth factor (HGF), matrix metalloproteinase-2, granulocyte macrophage colony-stimulating factor, and monocyte chemotactic protein (MCP)-1 by TAFs. Tumor cell-derived IL-1α was identified as a major mediator of these stimulatory effects. Fibroblasts, on the other hand, exerted a migration and invasion stimulating influence on UBC cells. MCP-1 and HGF were shown to promote cell migration of both bladder cancer cell lines.

Immunological basis in the pathogenesis and treatment of bladder cancer

The pathogenesis and transition of normal urothelium into bladder carcinoma are multifactorial processes. Chronic inflammation causes initiation and progression of the underlying pathophysiology of invasive and metastatic cancer. A dichotomy is observed in the role of immune cells in bladder cancer. While the immune response defends the host by suppressing neoplastic growth, several immune cells, including neutrophils, macrophages and T-lymphocytes, promote tumor development and progression. The levels of human neutrophil peptide-1, -2 and -3, produced by neutrophils, increase in bladder cancer and might promote tumor angiogenesis and growth. The effect of macrophages is primarily mediated by pro-inflammatory cytokines, IL-6 and TNF-α. In addition, the underlying immunological mechanisms of two treatments, BCG and cytokine gene-modified tumor vaccines, and future directions are critically discussed.

Identification of biomarkers for radiation-induced acute intestinal symptoms (RIAISs) in cervical cancer patients by serum protein profiling

Radiation-induced acute intestinal symptoms (RIAISs) are the most frequent complication of radiotherapy that causes great pain and limits the treatment efficacy. The aim of this study was to identify serum biomarkers of RIAISs in cervical cancer patients by surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS). Serum samples were collected from 66 cervical cancer patients prior to pelvic radiotherapy. In our study, RIAISs occurred in 11 patients. An additional 11 patients without RIAISs were selected as controls, whose age, stage, histological type and treatment methods were matched to RIAISs patients. The 22 sera were subsequently analyzed by SELDI-TOF MS, and the resulting protein profiles were evaluated to identify biomarkers using appropriate bioinformatics tools. Comparing the protein profiles of serum samples from the RIAIS group and the control group, it was found that 22 protein peaks were significantly different (P < 0.05), and six of these peaks with mass-to-charge (m/z) ratios of 7514.9, 4603.94, 6887.41, 2769.21, 3839.72 and 4215.7 were successfully identified. A decision tree model of biomarkers was constructed based on three biomarkers (m/z 1270.88, 1503.23 and 7514.90), which separated RIAIS-affected patients from the control group with an accuracy of 81%. This study suggests that serum proteomic analysis by SELDI-TOF MS can identify cervical cancer patients that are susceptible to RIAISs prior to pelvic radiotherapy.

In vivo delivery of miRNAs for cancer therapy: challenges and strategies

MicroRNAs (miRNAs), small non-coding RNAs, can regulate post-transcriptional gene expressions and silence a broad set of target genes. miRNAs, aberrantly expressed in cancer cells, play an important role in modulating gene expressions, thereby regulating downstream signaling pathways and affecting cancer formation and progression. Oncogenes or tumor suppressor genes regulated by miRNAs mediate cell cycle progression, metabolism, cell death, angiogenesis, metastasis and immunosuppression in cancer. Recently, miRNAs have emerged as therapeutic targets or tools and biomarkers for diagnosis and therapy monitoring in cancer. Since miRNAs can regulate multiple cancer-related genes simultaneously, using miRNAs as a therapeutic approach plays an important role in cancer therapy. However, one of the major challenges of miRNA-based cancer therapy is to achieve specific, efficient and safe systemic delivery of therapeutic miRNAs in vivo. This review discusses the key challenges to the development of the carriers for miRNA-based therapy and explores current strategies to systemically deliver miRNAs to cancer without induction of toxicity.

Stromal cells in tumor microenvironment and breast cancer

Cancer is a systemic disease encompassing multiple components of both tumor cells themselves and host stromal cells. It is now clear that stromal cells in the tumor microenvironment play an important role in cancer development. Molecular events through which reactive stromal cells affect cancer cells can be defined so that biomarkers and therapeutic targets can be identified. Cancer-associated fibroblasts (CAFs) make up the bulk of cancer stroma and affect the tumor microenvironment such that they promote cancer initiation, angiogenesis, invasion, and metastasis. In breast cancer, CAFs not only promote tumor progression but also induce therapeutic resistance. Accordingly, targeting CAFs provides a novel way to control tumors with therapeutic resistance. This review summarizes the current understandings of tumor stroma in breast cancer with a particular emphasis on the role of CAFs and the therapeutic implications of CAFs. In addition, the effects of other stromal components such as endothelial cells, macrophages, and adipocytes in breast cancer are also discussed. Finally, we describe the biologic markers to categorize patients into a specific and confirmed subtype for personalized treatment.

Functional heterogeneity of cancer-associated fibroblasts from human colon tumors shows specific prognostic gene expression signature

PURPOSE

Cancer-associated fibroblasts (CAF) actively participate in reciprocal communication with tumor cells and with other cell types in the microenvironment, contributing to a tumor-permissive neighborhood and promoting tumor progression. The aim of this study is the characterization of how CAFs from primary human colon tumors promote migration of colon cancer cells.

EXPERIMENTAL DESIGN

Primary CAF cultures from 15 primary human colon tumors were established. Their enrichment in CAFs was evaluated by the expression of various epithelial and myofibroblast specific markers. Coculture assays of primary CAFs with different colon tumor cells were performed to evaluate promigratory CAF-derived effects on cancer cells. Gene expression profiles were developed to further investigate CAF characteristics.

RESULTS

Coculture assays showed significant differences in fibroblast-derived paracrine promigratory effects on cancer cells. Moreover, the association between CAFs' promigratory effects on cancer cells and classic fibroblast activation or stemness markers was observed. CAF gene expression profiles were analyzed by microarray to identify deregulated genes in different promigratory CAFs. The gene expression signature, derived from the most protumorogenic CAFs, was identified. Interestingly, this "CAF signature" showed a remarkable prognostic value for the clinical outcome of patients with colon cancer. Moreover, this prognostic value was validated in an independent series of 142 patients with colon cancer, by quantitative real-time PCR (qRT-PCR), with a set of four genes included in the "CAF signature."

CONCLUSIONS

In summary, these studies show for the first time the heterogeneity of primary CAFs' effect on colon cancer cell migration. A CAF gene expression signature able to classify patients with colon cancer into high- and low-risk groups was identified.

Comprehensive microRNA Profiling of Prostate Cancer

MicroRNAs are small non-coding RNA molecules that have been shown to regulate the expression of genes linked to cancer. The relevance of microRNAs in the development, progression and prognosis of prostate cancer is not fully understood. It is also possible that these specific molecules may assist in the recognition of aggressive tumors and the development of new molecular targets. Our study investigated the importance of several microRNAs in cases of prostate cancer from 37 patients that were manually microdissected to obtain pure populations of tumor cells, normal epithelium and adjacent stroma. MicroRNA was extracted for PCR array profiling. Differentially expressed miRNAs for each case were used to compare tumor vs. normal epithelium and tumor-adjacent stroma samples. Loss of 18 miRNAs (e.g.miR-34c, miR-29b, miR-212 and miR-10b) and upregulation of miR-143 and miR-146b were significantly found in all the tumors in comparison with normal epithelium and/or stroma (p≤ 0.001). A different signature was found in the high grade tumors (Gleason score ≥ 8) when compared with tumors Gleason score 6. Upregulation of miR-122, miR-335, miR-184, miR-193, miR-34, miR-138, miR-373, miR-9, miR-198, miR-144 and miR-215 and downregulation of miR-96, miR-222, miR-148, miR-92, miR-27, miR-125, miR-126, miR-27 were found in the high grade tumors. MicroRNA profiling in prostate cancer appears to have unique expression patterns in comparison with normal tissue. These differential expressed miRNAs may provide novel diagnostic and prognostic tools that will assist in the recognition of prostate cancers with aggressive behavior.

Tumor-stromal interactions in breast tumor progression--significance of histological heterogeneity of tumor-stromal fibroblasts

INTRODUCTION

Existing pathological diagnostic protocols for breast cancer do not fully reflect the biological characteristics of tumor stromata. To improve the pathological diagnosis of breast cancer, a new pathological diagnostic method capable of assessing the degree of breast cancer malignancy based on the histological features of the tumor stroma is needed.

AREAS COVERED

The presence of a fibrotic focus (FF), which consists of fibroblasts or collagen fibers, and the presence of atypical tumor-stromal fibroblasts are significantly associated with nodal metastasis or distant-organ metastasis in patients with invasive ductal carcinoma (IDC) of the breast. FF is the only factor that is significantly associated with an increase in tumor angiogenesis. The importance of FF and atypical tumor-stromal fibroblasts clearly indicates that the malignant potential of IDC does not depend only on the biological characteristics of the tumor cell, but also on those of the tumor stroma.

EXPERT OPINION

The biological characteristics of fibroblasts forming an FF or atypical tumor-stromal fibroblasts probably differ from those of fibroblasts located outside an FF or ordinary tumor-stromal fibroblasts. Thus, similar to tumor cells, the heterogeneity of tumor-stromal fibroblasts probably influences the outcome of patients with IDC of the breast.

Circulating microRNAs: new biomarkers in diagnosis, prognosis and treatment of cancer (review)

MicroRNAs (miRNAs) are small non-coding, endogenous, single-stranded RNAs. MiRNAs have been implicated in different areas such as the immune response, neural development, DNA repair, apoptosis, oxidative stress response and cancer. However, while the majority of miRNAs are found intracellularly, a significant number of miRNAs have been observed outside of cells, including various body fluids. Circulating miRNAs function as 'extracellular communication RNAs' that play an important role in cell proliferation and differentiation. MiRNA regulation is essential to many cellular processes, and escape from this regulatory network seems to be a common characteristic of several disease processes and malignant transformation. The interest in circulating miRNAs reflects in fact their central role in regulation of gene expression and the implication of miRNA-specific aberrant expression in the pathogenesis of cancer, cardiac, metabolic, neurologic, immune-related diseases as well as others. In our review we aimed to summarize the data related to the action of cellular miRNAs on the onset of various diseases, thus bringing together some of the latest information available on the role of circulating miRNAs. Additionally, the role of circulating miRNAs could be particularly relevant in the context of neoplastic diseases. At least 79 miRNAs have been reported as plasma or serum miRNA biomarkers of solid and hematologic tumors. Circulating miRNA profiling could improve the diagnosis of cancer, and could predict outcome for cancer patients, while the profiling of alterations in circulating miRNA that may signal a predisposition to cancer, could also be a therapeutic target in these patients.

MiRNA expression analysis of cancer-associated fibroblasts and normal fibroblasts in breast cancer

Cancer-associated fibroblasts (CAFs) promote tumorigenesis, growth, invasion and metastasis of cancer, whereas normal fibroblasts (NFs) are thought to suppress tumor progression. Little is known about miRNAs expression differences between CAFs and NFs or the patient-to-patient variability in miRNAs expression in breast cancer. We established primary cultures of CAFs and paired NFs from six resected breast tumor tissues that had not previously received radiotherapy or chemotherapy treatment and analyzed with miRNAs microarrays. The array data were analyzed using paired SAM t-test and filtered according to α and q values. Pathway analysis was conducted using DAVID v6.7. We identified 11 dysregulated miRNAs in CAFs: three were up-regulated (miR-221-5p, miR-31-3p, miR-221-3p), while eight were down-regulated (miR-205, miR-200b, miR-200c, miR-141, miR-101, miR-342-3p, let-7g, miR-26b). Their target genes are known to affect cell differentiation, adhesion, migration, proliferation, secretion and cell-cell interaction. By our knowledge it is firstly identify the expression profiles of miRNAs between CAFs and NFs and revealed their regulation on the associated signaling pathways.

Circulating miRNA is a novel marker for head and neck squamous cell carcinoma

The aim of the study is to investigate the alteration of plasma miRNA in head and neck squamous cell carcinoma (HNSCC). Altered microRNAs (miRNAs) expression has been found in many cancers, including lung cancer, breast cancer, prostate cancer, bladder cancer and colorectal cancer. Many recent studies have demonstrated that aberrant plasma miRNAs were also found in various types of cancers. However the alteration of plasma expression in HNSCC remains unclear. In this present study, the expression profiles of ten miRNAs, let-7a, miR-21, miR26b, miR-34c, miR-99a, miR-133a, miR-137, miR-184, miR-194a, and miR-375, in plasma from 50 patients and 36 healthy subjects were evaluated using real-time quantitative polymerase chain reaction (PCR). Our results demonstrated that the expression level of miR-21 was significantly up-regulated in plasma samples obtained from HNSCC patients (p < 0.01) than those from healthy subjects, which were in consistent with our finding in HNSCC tissues. A 7.7-fold increase of miR-21 in cancerous parts when compared to their non-cancerous counterparts (p < 0.0001) was observed in HNSCC tissues. In addition, the expression levels of miR-21 and miR-26b were both reduced in post-operative HNSCC patients with good prognosis. In contrast, the concentration of plasma miR-21 and miR-26b stayed high after tumor removal in the expired cases. Our study suggests that detecting circulating miR-21 and miR-26b pre- and post-operatively might provide a novel tumor marker for HNSCC.

Proteomic analysis of primary colon cancer-associated fibroblasts using the SELDI-ProteinChip platform

OBJECTIVE

Cancer-associated fibroblasts (CAFs) are one of the hallmarks of the cancer microenvironment. Recent evidence has indicated that CAFs are more competent in enhancing cancer cell growth and migration than normal fibroblasts. However, the unique protein expression of CAFs has not been fully elucidated. This study aims to investigate the characterizations of colon CAFs by comparing the differential protein expression between CAFs and normal fibroblasts.

METHODS

Primary fibroblasts were isolated from surgical specimen of human colon cancer and matched normal colonic tissue. Purity of the cell population was verified through immunostain analysis. Total cell lysates and conditioned media from each group of cells were extracted, and protein expression analysis was conducted using the surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS) ProteinChip platform.

RESULTS

Most primary cells showed typical fibroblast-like features after two weeks. Increased proportion of α-smooth muscle actin-positive myofibroblasts was detected within the CAFs in four of the six pairs of primary cells. Fibroblast activation protein was weakly expressed in most cells without differences. Using SELDI-TOF-MS ProteinChip platform, four protein peaks mass over charge ratio (m/z) 1142, 3011, 4035, and 4945 were detected in the total cell lysates, and two protein peaks m/z 1368 and 1389 were detected in the conditioned media. The potential candidate proteins found in the Swiss-Prot database include morphogenetic neuropeptides, FMRFamide-related peptides, insulin-like growth factor II, thymosin β-4-like protein 3, and tight junction-associated protein 1.

CONCLUSIONS

Using the SELDI-ProteinChip platform, differential protein expressions were identified in colon CAFs compared with normal colonic stromal fibroblasts. The complex proteomic alternations in colon CAFs may play important roles related to the colon cancer microenvironment.

Epithelial plasticity, cancer stem cells, and the tumor-supportive stroma in bladder carcinoma

High recurrence rates and poor survival rates of metastatic bladder cancer emphasize the need for a drug that can prevent and/or treat bladder cancer progression and metastasis formation. Accumulating evidence suggests that cancer stem/progenitor cells are involved in tumor relapse and therapy resistance in urothelial carcinoma. These cells seem less affected by the antiproliferative therapies, as they are largely quiescent, have an increased DNA damage response, reside in difficult-to-reach, protective cancer stem cell niches and express ABC transporters that can efflux drugs from the cells. Recent studies have shown that epithelial-to-mesenchymal transition (EMT), a process in which sessile, epithelial cells switch to a motile, mesenchymal phenotype may render cancer cells with cancer stem cells properties and/or stimulate the expansion of this malignant cellular subpopulation. As cancer cells undergo EMT, invasiveness, drug resistance, angiogenesis, and metastatic ability seem to increase in parallel, thus giving rise to a more aggressive tumor type. Furthermore, the tumor microenvironment (tumor-associated stromal cells, extracellular matrix) plays a key role in tumorigenesis, tumor progression, and metastasis formation. Taken together, the secret for more effective cancer therapies might lie in developing and combining therapeutic strategies that also target cancer stem/progenitor cells and create an inhospitable microenvironment for highly malignant bladder cancer cells. This review will focus on the current concepts about the role of cancer stem cells, epithelial plasticity, and the supportive stroma in bladder carcinoma. The potential implications for the development of novel bladder cancer therapy will be discussed.

The role of the androgen receptor in the development and progression of bladder cancer

Men are at a higher risk of developing bladder cancer than women. Since bladder cancer cell lines and tissues were found to express the androgen receptor, efforts have been made to inspect whether androgen-mediated androgen receptor signals are implicated in bladder carcinogenesis as well as cancer progression. Mounting evidence supports the view that bladder cancer is a member of the endocrine-related tumors and may clearly explain the gender-specific difference in the incidence. However, the underlying mechanisms of how androgen receptor signals regulate bladder cancer growth are still far from fully characterized. Moreover, it remains controversial whether the androgen receptor pathway always plays a dominant role in bladder cancer progression. In this review, we summarize the available data on the involvement of androgen receptor signaling in bladder cancer. In particular, current evidence demonstrating the stimulatory effects of androgens on tumor progression or, more convincingly, tumorigenesis via the androgen receptor pathway may offer great potential for androgen deprivation as a therapeutic or chemopreventive option in patients with bladder cancer.

MicroRNAs in pancreatic cancer metabolism

Advances in understanding the biology of tumour progression and metastasis have clearly highlighted the importance of aberrant tumour metabolism, which supports not only the energy requirements but also the enormous biosynthetic needs of tumour cells. Such metabolic alterations modulate glucose, amino acid and fatty-acid-dependent metabolite biosynthesis and energy production. Although much progress has been made in understanding the somatic mutations and expression genomics behind these alterations, the regulation of these processes by microRNAs (miRNAs) is only just beginning to be appreciated. This Review focuses on the miRNAs that are potential regulators of the expression of genes whose protein products either directly regulate metabolic machinery or serve as master regulators, indirectly modulating the expression of metabolic enzymes. We focus particularly on miRNAs in pancreatic cancer.

Interrogation of rabbit miRNAs and their isomiRs

Rabbit (Oryctolagus cuniculus) is the only lagomorph animal of which the genome has been sequenced. Establishing a rabbit miRNA resource will benefit subsequent functional genomic studies in mammals. We have generated small RNA sequence reads with SOLiD and Solexa platforms to identify rabbit miRNAs, where we identified 464 pre-miRNAs and 886 mature miRNAs. The brain and heart miRNA libraries were used for further in-depth analysis of isomiR distributions. There are several intriguing findings. First, several rabbit pre-miRNAs form highly conserved clusters. Second, there is a preference in selecting one strand as mature miRNA, resulting in an arm selection preference. Third, we analyzed the isomiR expression and validated the expression of isomiR types in different rabbit tissues. Moreover, we further performed additional small RNA libraries and defined miRNAs differentially expressed between brain and heart. We conclude also that isomiR distribution profiles could vary between brain and heart tissues.

The Role of miRNAs as Key Regulators in the Neoplastic Microenvironment

The neoplastic microenvironment has been recognized to play a critical role in the development of cancer. Although a large body of evidence has established the importance of the cancer microenvironment, the manners of crosstalk between it and the cancer cells still remains unclear. Emerging mechanisms of communication include microRNAs (miRNAs). miRNAs are small noncoding RNA molecules that are involved in the posttranscriptional regulation of mRNA. Both intracellular and circulating miRNAs are differentially expressed in cancer and some of these alterations have been correlated with clinical patient outcomes. The role of miRNAs in the tumor microenvironment has only recently become a focus of research, however. In this paper, we discuss the influence of miRNAs on the tumor microenvironment as it relates to cancer progression. We conclude that miRNAs are a critical component in understanding invasion and metastasis of cancer cells.