Loss of EGFR signaling regulated miR-203 promotes prostate cancer bone metastasis and tyrosine kinase inhibitors resistance

CircTHSD4 promotes the malignancy and docetaxel (DTX) resistance in prostate cancer by regulating miR-203/HMGA2 axis

Objective

Circular ribose nucleic acids (circRNAs) are implicated in tumor progression and drug resistance of prostate cancer (PCa). The current work explored the function of circ_0005203 (circTHSD4) in the malignancy and docetaxel (DTX) resistance of PCa.

Methods

circTHSD4 expression within PCa as well as matched non-carcinoma samples was measured through real-time reverse transcription-quantitative polymerase chain reaction (RT-qPCR). In addition, a subcellular fraction assay was conducted to determine circTHSD4 subcellular localization within PCa cells. In addition, we performed a Western blot (WB) assay to detect high-mobility-group A2 protein (HMGA2) levels. Besides, functional associations of two molecules were investigated through dual luciferase reporter assay. Cell Counting Kit (CCK)-8, colony formation together with Transwell assay was conducted to assess malignant phenotypes of PCa cells, whereas flow cytometry was performed to determine cell apoptosis. Furthermore, a xenograft mouse model was constructed to verify the effect of circTHSD4 on the carcinogenesis of PCa cells.

Results

According to RT-qPCR results, circTHSD4 was up-regulated within PCa tissues and cells, which predicted the dismal prognostic outcome of PCa cases. circTHSD4 silencing within PCa cells markedly suppressed cell growth, migration, and colony formation. circTHSD4 silencing remarkably elevated PCa cell apoptosis and carcinogenesis within the xenograft model. Further, circTHSD4 silencing enhanced docetaxel (DTX) sensitivity in PCa cells. Furthermore, we demonstrated that circTHSD4 modulated the malignancy of PCa cells by regulating HMGA2 expression through sponging miR-203.

Conclusion

Together, our findings suggest that circTHSD4 overexpression could promote the malignant phenotype and DTX resistance in PCa through the regulation of the miR-203/HMGA2 axis.

Targeting the p53 signaling pathway in cancers: Molecular mechanisms and clinical studies

Tumor suppressor p53 can transcriptionally activate downstream genes in response to stress, and then regulate the cell cycle, DNA repair, metabolism, angiogenesis, apoptosis, and other biological responses. p53 has seven functional domains and 12 splice isoforms, and different domains and subtypes play different roles. The activation and inactivation of p53 are finely regulated and are associated with phosphorylation/acetylation modification and ubiquitination modification, respectively. Abnormal activation of p53 is closely related to the occurrence and development of cancer. While targeted therapy of the p53 signaling pathway is still in its early stages and only a few drugs or treatments have entered clinical trials, the development of new drugs and ongoing clinical trials are expected to lead to the widespread use of p53 signaling-targeted therapy in cancer treatment in the future. TRIAP1 is a novel p53 downstream inhibitor of apoptosis. TRIAP1 is the homolog of yeast mitochondrial intermembrane protein MDM35, which can play a tumor-promoting role by blocking the mitochondria-dependent apoptosis pathway. This work provides a systematic overview of recent basic research and clinical progress in the p53 signaling pathway and proposes that TRIAP1 is an important therapeutic target downstream of p53 signaling.

Epiregulin expression and secretion is increased in castration-resistant prostate cancer

Introduction

In prostate cancer, long-term treatment directed against androgens often leads to the development of metastatic castration-resistant prostate cancer, which is more aggressive and not curatively treatable. Androgen deprivation results in elevated epiregulin expression in LNCaP cells which is a ligand of EGFR. This study aims to reveal the expression and regulation of epiregulin in different prostate cancer stages enabling a more specific molecular characterization of different prostate carcinoma types.

Methods

Five different prostate carcinoma cell lines were used to characterize the epiregulin expression on the RNA and protein levels. Epiregulin expression and its correlation with different patient conditions were further analyzed using clinical prostate cancer tissue samples. Additionally, the regulation of epiregulin biosynthesis was examined at transcriptional, post-transcriptional and release level.

Results

An increased epiregulin secretion is detected in castration-resistant prostate cancer cell lines and prostate cancer tissue samples indicating a correlation of epiregulin expression with tumor recurrence, metastasis and increased grading. Analysis regarding the activity of different transcription factors suggests the involvement of SMAD2/3 in the regulation of epiregulin expression. In addition, miR-19a, -19b, and -20b are involved in post-transcriptional epiregulin regulation. The release of mature epiregulin occurs via proteolytic cleavage by ADAM17, MMP2, and MMP9 which are increased in castration-resistant prostate cancer cells.

Discussion

The results demonstrate epiregulin regulation by different mechanism and suggest a potential role as a diagnostic tool to detect molecular alterations in prostate cancer progression. Additionally, although EGFR inhibitors false in prostate cancer, epiregulin could be a therapeutic target for patients with castration-resistant prostate cancer.

The Intricate Interplay between the ZNF217 Oncogene and Epigenetic Processes Shapes Tumor Progression

The oncogenic transcription factor ZNF217 orchestrates several molecular signaling networks to reprogram integrated circuits governing hallmark capabilities within cancer cells. High levels of ZNF217 expression provide advantages to a specific subset of cancer cells to reprogram tumor progression, drug resistance and cancer cell plasticity. ZNF217 expression level, thus, provides a powerful biomarker of poor prognosis and a predictive biomarker for anticancer therapies. Cancer epigenetic mechanisms are well known to support the acquisition of hallmark characteristics during oncogenesis. However, the complex interactions between ZNF217 and epigenetic processes have been poorly appreciated. Deregulated DNA methylation status at ZNF217 locus or an intricate cross-talk between ZNF217 and noncoding RNA networks could explain aberrant ZNF217 expression levels in a cancer cell context. On the other hand, the ZNF217 protein controls gene expression signatures and molecular signaling for tumor progression by tuning DNA methylation status at key promoters by interfering with noncoding RNAs or by refining the epitranscriptome. Altogether, this review focuses on the recent advances in the understanding of ZNF217 collaboration with epigenetics processes to orchestrate oncogenesis. We also discuss the exciting burgeoning translational medicine and candidate therapeutic strategies emerging from those recent findings connecting ZNF217 to epigenetic deregulation in cancer.

Validation of AAC-11-Derived Peptide Anti-Tumor Activity in a Single Graft Sézary Patient-Derived Xenograft Mouse Model

Sézary syndrome (SS) is an aggressive cutaneous T cell lymphoma with poor prognosis mainly characterized by the expansion of a tumor CD4⁺ T cell clone in both skin and blood. So far, the development of new therapeutic strategies has been hindered by a lack of reproducible in vivo models closely reflecting patients’ clinical features. We developed an SS murine model consisting of the intravenous injection of Sézary patients’ PBMC, together with a mixture of interleukins, in NOD-SCID-gamma mice. Thirty-four to fifty days after injection, mice showed skin disorders similar to that observed in patients, with the detection of epidermis thickening and dermal tumor T cell infiltrates. Although experimental variability was observed, Sézary cells could be tracked in the blood stream, confirming that our model could efficiently exhibit both skin and blood involvement. Using this model, we evaluated the therapeutic potential of RT39, a cell-penetrating peptide derived from the survival protein anti-apoptosis clone 11 (AAC-11), that we previously characterized as specifically inducing apoptosis of Sézary patients’ malignant clone ex vivo. Systemic administration of RT39 led to cutaneous tumor T cells depletion, demonstrating efficient malignant cells’ targeting and a favorable safety profile. These preclinical data confirmed that RT39 might be an innovative therapeutic tool for Sézary syndrome.

An Integrative Transcriptomic Analysis Reveals EGFR Exon-19 E746-A750 Fragment Deletion Regulated miRNA, circRNA, mRNA and lncRNA Networks in Lung Carcinoma

Introduction

Competing endogenous RNA (ceRNA) appears to be an important post-transcriptional manner that regulates gene expression through a miRNA-mediated mechanism. Mutations in exon-19 of EGFR were frequently observed in lung cancer genes, which were associated with EGFR activity and EGFR-targeted therapies.

Methods

We explored the transcriptome regulated by mutation in EGFR exon-19 E746-A750 fragment via using a network modeling strategy. We applied transcriptome sequencing to detect the deletion process of EGFR exon-19 E746-A750 fragment. Bio-informatics analyses were used to predict the gene target pairs and explain their potential roles in tumorigenesis and progression of lung cancer.

Results

We conducted an explorative lncRNA/miRNA/circRNA and mRNA expression study with two groups of lung adenocarcinoma tissues, including EGFR exon-19 E746-A750 deletion group and EGFR exon-19 wild-type group. Meanwhile, we screen out the hub genes related to the EGFR-19-D patient. Significant pathways and biological functions potentially regulated by the deregulated 128 non-coding genes were enriched.

Conclusion

Our work provides an important theoretical, experimental and clinical foundation for further research on more effective targets for the diagnosis, therapy and prognosis of lung cancer.

MicroRNAs as the critical regulators of protein kinases in prostate and bladder cancers

Background

Bladder cancer (BCa) and prostate cancer (PCa) are frequent urothelial and genital malignancies with a high ratio of morbidity and mortality which are more common among males. Since BCa and PCa cases are mainly diagnosed in advanced stages with clinical complications, it is required to introduce the efficient early detection markers. Protein kinases are critical factors involved in various cellular processes such as cell growth, motility, differentiation, and metabolism. Deregulation of protein kinases can be frequently observed through the neoplastic transformation and tumor progression. Therefore, kinases are required to be regulated via different genetic and epigenetic processes. MicroRNAs (miRNAs) are among the critical factors involved in epigenetic regulation of protein kinases. Since miRNAs are noninvasive and more stable factors in serum and tissues compared with mRNAs, they can be used as efficient diagnostic markers for the early detection of PCa and BCa.

Main body

In present review, we have summarized all of the reported miRNAs that have been associated with regulation of protein kinases in bladder and prostate cancers.

Conclusions

For the first time, this review highlights the miRNAs as critical factors in regulation of protein kinases during prostate and bladder cancers which paves the way of introducing a noninvasive kinase-specific panel of miRNAs for the early detection of these malignancies. It was observed that the class VIII receptors of tyrosine kinases and non-receptor tyrosine kinases were the most frequent targets for the miRNAs in bladder and prostate cancers, respectively.

PAK1-Dependent Antitumor Effect of AAC-11‒Derived Peptides on Sézary Syndrome Malignant CD4+ T Lymphocytes

Sézary syndrome is an aggressive form of cutaneous T-cell lymphoma characterized by the presence of a malignant CD4⁺ T-cell clone in both blood and skin. Its pathophysiology is still poorly understood, and the development of targeted therapies is hampered by the absence of specific target proteins. AAC-11 plays important roles in cancer cell progression and survival and thus has been considered as an anticancer therapeutic target. In this study, we show that a peptide called RT39, comprising a portion of AAC-11‒binding site to its protein partners coupled to the penetratin sequence, induces the specific elimination of the malignant T-cell clone both ex vivo on the circulating cells of patients with Sézary syndrome and in vivo in a subcutaneous xenograft mouse model. RT39 acts by direct binding to PAK1 that is overexpressed, located in the plasma membrane, and constitutively activated in Sézary cells, resulting in their selective depletion by membranolysis. Along with the absence of toxicity, our preclinical efficacy evidence suggests that RT39 might represent a promising alternative therapeutic tool for Sézary syndrome because it spares the nonmalignant immune cells and, contrary to antibody-based immunotherapies, does not require the mobilization of the cellular immunity that shows heavy deficiencies at advanced stages of the disease.

miRNAs as Therapeutic Tools and Biomarkers for Prostate Cancer

Prostate cancer (PCa) is the fifth cause of tumor-related deaths in man worldwide. Despite the considerable improvement in the clinical management of PCa, several limitations emerged both in the screening for early diagnosis and in the medical treatment. The use of prostate-specific antigen (PSA)-based screening resulted in patients’ overtreatment and the standard therapy of patients suffering from locally advanced/metastatic tumors (e.g., radical prostatectomy, radiotherapy, and androgen deprivation therapy) showed time-limited efficacy with patients undergoing progression toward the lethal metastatic castration-resistant PCa (mCRPC). Although valuable alternative therapeutic options have been recently proposed (e.g., docetaxel, cabazitaxel, abiraterone, enzalutamide, and sipuleucel-T), mCRPC remains incurable. Based on this background, there is an urgent need to identify new and more accurate prostate-specific biomarkers for PCa diagnosis and prognosis and to develop innovative medical approaches to counteract mCRPC. In this context, microRNA (miRNAs) emerged as potential biomarkers in prostate tissues and biological fluids and appeared to be promising therapeutic targets/tools for cancer therapy. Here we overview the recent literature and summarize the achievements of using miRNAs as biomarkers and therapeutic targets/tools for fighting PCa.

MiR-155-5p and MiR-203a-3p Are Prognostic Factors in Soft Tissue Sarcoma

Soft tissue sarcoma (STS) is a heterogeneous group of rare malignancies with a five-year survival rate of approximately 50%. Reliable molecular markers for risk stratification and subsequent therapy management are still needed. Therefore, we analyzed the prognostic potential of miR-155-5p and miR-203a-3p expression in a cohort of 79 STS patients. MiR-155-5p and miR-203a-3p expression was measured from tumor total RNA by qPCR and correlated with the demographic, clinicopathological, and prognostic data of the patients. Elevated miR-155-5p expression was significantly associated with increased tumor stage and hypoxia-associated mRNA/protein expression. High miR-155-5p expression and low miR-203a-3p expression, as well as a combination of high miR-155-5p and low miR-203a-3p expression, were significantly associated with poor disease-specific survival in STS patients in the Kaplan–Meier survival analyses (p = 0.027, p = 0.001 and p = 0.0003, respectively) and in the univariate Cox regression analyses (RR = 1.96; p = 0.031; RR = 2.59; p = 0.002 and RR = 4.76; p = 0.001, respectively), but not in the multivariate Cox regression analyses. In conclusion, the oncomiR miR-155-5p and the tumor suppressor-miR miR-203a-3p exhibit an association with STS patient prognosis and are suggested as candidates for risk assessment.

Inflammatory Breast Carcinoma: Elevated microRNA miR-181b-5p and Reduced miR-200b-3p, miR-200c-3p, and miR-203a-3p Expression as Potential Biomarkers with Diagnostic Value

Inflammatory breast cancer (IBC) is a rare yet aggressive breast cancer variant, associated with a poor prognosis. The major challenge for IBC is misdiagnosis due to the lack of molecular biomarkers. We profiled dysregulated expression of microRNAs (miRNAs) in primary samples of IBC and non-IBC tumors using human breast cancer miRNA PCR array. We discovered that 28 miRNAs were dysregulated (10 were upregulated, while 18 were underexpressed) in IBC vs. non-IBC tumors. We identified 128 hub genes, which are putative targets of the differentially expressed miRNAs and modulate important cancer biological processes. Furthermore, our qPCR analysis independently verified a significantly upregulated expression of miR-181b-5p, whereas a significant downregulation of miR-200b-3p, miR-200c-3p, and miR-203a-3p was detected in IBC tumors. Receiver operating characteristic (ROC) curves implied that the four miRNAs individually had a diagnostic accuracy in discriminating patients with IBC from non-IBC and that miR-203a-3p had the highest diagnostic value with an AUC of 0.821. Interestingly, a combination of miR-181b-5p, miR-200b-3p, and miR-200c-3p robustly improved the diagnostic accuracy, with an area under the curve (AUC) of 0.897. Intriguingly, qPCR revealed that the expression of zinc finger E box-binding homeobox 2 (ZEB2) mRNA, the putative target of miR-200b-3p, miR-200c-3p, and miR-203a-3p, was upregulated in IBC tumors. Overall, this study identified a set of miRNAs serving as potential biomarkers with diagnostic relevance for IBC.

Detection and Prognosis of Prostate Cancer Using Blood-Based Biomarkers

Prostate cancer (PCa) is second only to lung cancer as a cause of death. Clinical assessment of patients and treatment efficiency therefore depend on the disease being diagnosed as early as possible. However, due to issues regarding the use of prostate-specific antigen (PSA) for screening purposes, PCa management is among the most contentious of healthcare matters. PSA screening is problematic primarily because of diagnosis difficulties and the high rate of false-positive biopsies. Novel PCa biomarkers, such as the Prostate Health Index (PHI) and the 4Kscore, have been proposed in recent times to improve PSA prediction accuracy and have shown higher performance by preventing redundant biopsies. The 4Kscore also shows high precision in determining the risk of developing high-grade PCa, whereas elevated PHI levels suggest that the tumor is aggressive. Some evidence also supports the effectiveness of miRNAs as biomarkers for distinguishing PCa from benign prostatic hyperplasia and for assessing the aggressiveness of the disease. A number of miRNAs that possibly act as tumor inhibitors or oncogenes are impaired in PCa. These new biomarkers are comprehensively reviewed in the present study in terms of their potential use in diagnosing and treating PCa.

miR-143 inhibits renal cell carcinoma cells metastatic potential by suppressing ABL2

Although micro RNA (miRNA) expression profiles are widely investigated in renal cell carcinoma (RCC), their potential roles for affecting RCC initiation and progression remain largely unknown. Here, we examined the aberrant expression profiles of miRNAs inhuman metastatic RCC tissues based on Gene Expression Omnibus (GSE37989). We further validated them iRNAs expression data in the largest clinical dataset: The Cancer Genome Atlas (TCGA). And cell adhesion and migration abilities and epithelial me senchymal transition (EMT) related proteins were assessed in both normal and tumor RCC cell lines. We suggest that hsa-miR-143 is a potential tumor suppressor in RCC as its down regulation positively correlated with adverse prognosis. Biologically, cell adhesion, migration, and EMT were dramatically inhibited by miR-143. Mechanistically, we found that miR-143 targets ABL proto-oncogene 2 (ABL2), which was also found to be an indicator for poor survival in TCGA database. Our results have important implications in understanding functions of miRNAs in metastatic RCC and will provide a basis for further clinical application.

Role of MicroRNAs in Anesthesia-Induced Neurotoxicity in Animal Models and Neuronal Cultures: a Systematic Review

Exposure to anesthetic agents in early childhood or late intrauterine life might be associated with neurotoxicity and long-term neurocognitive decline in adulthood. This could be attributed to induction of neuroapoptosis and inhibition of neurogenesis by several mechanisms, with a pivotal role of microRNAs in this milieu. MicroRNAs are critical regulators of gene expression that are differentially expressed in response to internal and external environmental stimuli, including general anesthetics. Through this systematic review, we aimed at summarizing the current knowledge apropos of the roles and implications of deregulated microRNAs pertaining to anesthesia-induced neurotoxicity in animal models and derived neuronal cultures. OVID/Medline and PubMed databases were lastly searched on April 1st, 2019, using the Medical Subject Heading (MeSH) or Title/Abstract words ("microRNA" and "anesthesia"), to identify all published research studies on microRNAs and anesthesia. During the review process, data abstraction and methodological assessment was done by independent groups of reviewers. In total, 29 studies were recognized to be eligible and were thus involved in this systematic review. Anesthetic agents studied included sevoflurane, isoflurane, propofol, bupivacaine, and ketamine. More than 40 microRNAs were identified to have regulatory roles in anesthesia-induced neurotoxicity. This field of study still comprises several gaps that should be filled by conducting basic, clinical, and translational research in the future to decipher the exact role of microRNAs and their functions in the context of anesthesia-induced neurotoxicity.

TRIAP1 Inhibition Activates the Cytochrome c/Apaf-1/Caspase-9 Signaling Pathway to Enhance Human Ovarian Cancer Sensitivity to Cisplatin

OBJECTIVE

To investigate whether TRIAP1inhibition affects the ovarian cancer cell resistance to cisplatin (DDP) via the Cyt c/Apaf-1/caspase-9 pathway by in vitro and in vivo experiments.

METHODS

CCK8 assay was performed to find out how treatment with both TRIAP1 siRNA and DDP affects the cell viability of SKOV3 cells and DDP-resistant human ovarian carcinoma cell line SKOV3/DDP. SKOV3/DDP cells were transfected with control siRNA or TRIAP1 siRNA before 24 h of treatment with DDP (5 μg/mL). Flow cytometry was employed to detect cell apoptosis and Western blot to examine the expressions of Cyt c/Apaf-1/caspase-9 pathway-related proteins. SKOV3/DDP cells transfected with control siRNA or TRIAP1 siRNA were subcutaneously injected into BALB/c-nu/nu nude mice followed by the intraperitoneal injection of DDP (4 mg/kg). Cyt c/Apaf-1/caspase-9 pathway in transplanted tumors was detected by immunohistochemistry.

RESULTS

TRIAP1 expression declined in SKOV3 cells when compared with SKOV3/DDP cells. The proliferation rate was lower in SKOV3/DDP cells transfected with TRIAP1 siRNA combined with treatment of DDP (1, 2, 4, 6, 8, 16, 32 μg/mL) than in those transfected with control siRNA. Moreover, the TRIAP1 siRNA group had an increased SKOV3/DDP cell apoptosis rate with the activation of the Cyt c/Apaf-1/caspase-9 pathway. During DDP treatment, nude mice in TRIAP1 siRNA group had slower growth and smaller size of transplanted tumor than those in control siRNA group, with increased expression of Cyt c, Apaf-1, and caspase-9.

CONCLUSION

TRIAP1 inhibition may enhance the sensitivity of SKOV3/DDP cells to cisplatin via activation of the Cyt c/Apaf-1/caspase-9 pathway.

Induction of Acquired Resistance towards EGFR Inhibitor Gefitinib in a Patient-Derived Xenograft Model of Non-Small Cell Lung Cancer and Subsequent Molecular Characterization

In up to 30% of non-small cell lung cancer (NSCLC) patients, the oncogenic driver of tumor growth is a constitutively activated epidermal growth factor receptor (EGFR). Although these patients gain great benefit from treatment with EGFR tyrosine kinase inhibitors, the development of resistance is inevitable. To model the emergence of drug resistance, an EGFR-driven, patient-derived xenograft (PDX) NSCLC model was treated continuously with Gefitinib in vivo. Over a period of more than three months, three separate clones developed and were subsequently analyzed: Whole exome sequencing and reverse phase protein arrays (RPPAs) were performed to identify the mechanism of resistance. In total, 13 genes were identified, which were mutated in all three resistant lines. Amongst them the mutations in NOMO2, ARHGEF5 and SMTNL2 were predicted as deleterious. The 53 mutated genes specific for at least two of the resistant lines were mainly involved in cell cycle activities or the Fanconi anemia pathway. On a protein level, total EGFR, total Axl, phospho-NFκB, and phospho-Stat1 were upregulated. Stat1, Stat3, MEK1/2, and NFκB displayed enhanced activation in the resistant clones determined by the phosphorylated vs. total protein ratio. In summary, we developed an NSCLC PDX line modelling possible escape mechanism under EGFR treatment. We identified three genes that have not been described before to be involved in an acquired EGFR resistance. Further functional studies are needed to decipher the underlying pathway regulation.

Effects of MiR-107 on The Chemo-drug Sensitivity of Breast Cancer Cells

Background

A growing body of evidence indicates that aberrant expression of miR-107 plays a core role in cancers. This study aims to demonstrate the function of miR-107 and its roles in chemo-drug resistance in breast cancer cells.

Methodology

CCK-8 assays were carried out to test the effect of miR-107 mimics on the proliferation of MCF-7 cells. The apoptosis level of each group was detected by flow cytometry. miR-107 level, mRNA levels of Bcl-2/Bax and TRIAP1 were detected by quantitative real-time Polymerase Chain Reaction (qRT-PCR) analysis. Protein levels of Bcl-2/Bax, p-Akt/Akt in MCF-7 cells were detected by using Western Blot. Lastly, the dual luciferase reporter gene assay system was used to confirm interaction between miR-107 and its target gene TRIAP1.

Results

CCK-8 assays indicated that miR-107 mimics augmented Taxol-induced cell viability inhibition. Flow cytometry showed that miR-107 mimics augmented Taxol-induced elevation of cell apoptosis. qRT-PCR analysis revealed that miR-107 mimics inhibited the mRNA expression of Bcl-2 and induced the mRNA level of Bax. Western Blotting indicated that miR-107 mimics inhibited the expression of proteins Bcl-2 and p-Akt, and induced the expression of Bax, while showing no significant effects on Akt. The relative luciferase activity revealed that oncogene TRIAP1 is a potential target gene of miR-107.

Conclusions

miR-107 plays a role in regulating chemo-drug sensitivity in mammary cancer cell by targeting TRIAP1.

The Functional Role of Prostate Cancer Metastasis-related Micro-RNAs

The mortality of patients with hormone-resistant prostate cancer can be ascribed to a large degree to metastasis to distant organs, predominantly to the bones. In this review, we discuss the contribution of micro-RNAs (miRs) to the metastatic process of prostate cancer. The criteria for selection of miRs for this review were the availability of preclinical in vivo metastasis-related data in conjunction with prognostic clinical data. Depending on their function in the metastatic process, the corresponding miRs are up- or down-regulated in prostate cancer tissues when compared to matching normal tissues. Up-regulated miRs preferentially target suppressors of cytokine signaling or tumor suppressor-related genes and metastasis-inhibitory transcription factors. Down-regulated miRs promote epithelial-mesenchymal transition or mesenchymal-epithelial transition and diverse pro-metastatic signaling pathways. Some of the discussed miRs exert their function by simultaneously targeting epigenetic pathways as well as cell-cycle-related, anti-apoptotic and signaling-promoting targets. Finally, we discuss potential therapeutic options for the treatment of prostate cancer-related metastases by substitution or inhibition of miRs.

MicroRNAs in prostate cancer: From function to biomarker discovery

MicroRNAs (miRNAs) are a small functional non-coding RNAs that post-transcriptionally regulate gene expression through mRNA degradation or translational repression. miRNAs are key regulatory components of various cellular networks. Current evidence support that multiple mammalian genome-encoded miRNAs impact the cellular biology, including proliferation, apoptosis, differentiation, and tumorigenesis, by targeting specific subsets of mRNAs. This minireview is focused on the current themes underlying the interactions between miRNAs and their mRNA targets and pathways in prostate tumorigenesis and progression, and their potential clinical utility as biomarkers for prostate cancer. Impact statement The primary goal of this article was to review recent literature on miRNA biogenesis and further elaborate on the identity of newly discovered miRNAs and their potential functional significance in the complex biological network associated with prostate tumorigenesis and disease progression and as biomarkers for prostate cancer.

Androgen deprivation-induced ZBTB46-PTGS1 signaling promotes neuroendocrine differentiation of prostate cancer

Androgen receptor (AR) targeting is an important therapeutic strategy for treating prostate cancer. Most tumors progress to castration-resistant prostate cancer (CRPC) and develop the neuroendocrine (NE) phenotype under androgen deprivation therapy (ADT). The molecular basis for NE transdifferentiation after ADT remains incompletely understood. Herein, we show that an immunocyte expression protein, ZBTB46, induces inflammatory response gene expression and contributes to NE differentiation of prostate cancer cells. We demonstrated a molecular mechanism whereby ZBTB46 can be regulated by the androgen-responsive gene, SPDEF, and is associated with NE prostate cancer (NEPC) differentiation. In addition, ZBTB46 acts as a transcriptional coactivator that binds to the promoter of prostaglandin-endoperoxide synthase 1 (PTGS1) and transcriptionally regulated PTGS1 levels. Overexpression of ZBTB46 decreases the sensitivity of the combination of enzalutamide and a PTGS1 inhibitor; however, knockdown of ZBTB46 sensitizes the PTGS1 inhibitor and reduces tumor malignancy. ZBTB46 is inversely correlated with SPDEF and is increased in higher tumor grades and small-cell NE prostate cancer (SCNC) patients, which are positively associated with PTGS1. Our findings suggest that the induction of ZBTB46 results in increased PTGS1 expression, which is associated with NEPC progression and linked to the dysregulation of the AR-SPDEF pathway.

Prognostic significance of the expression of HER family members in primary osteosarcoma

The prognosis of patients with metastatic osteosarcoma is poor and has shown no significant improvement in nearly 20 years. The human epidermal growth factor (EGF) receptor (HER) family is frequently overexpressed in the majority of human carcinomas, and is involved in promoting the proliferation and survival of cancer cells. However, the role of EGFR and HER-2 expression in osteosarcoma survival remains controversial and no previous study has simultaneously investigated the association of the expression of all the four HER family members with the prognostic significance of osteosarcoma. Therefore, the present study investigated the expression levels of the complete members of the HER family in osteosarcoma specimens, as well as their associations with the clinicopathological parameters, progression-free survival (PFS) and overall survival (OS) time of patients with osteosarcoma. The expression of HER family members was detected in osteosarcoma tumor specimens from 60 patients using immunohistochemistry. The association of the expression of HER receptors in osteosarcoma with clinicopathological parameters was analyzed using χ² test and Fishers exact test. Survival analyses were evaluated by Kaplan-Meier method and Cox proportional hazards regression model. Overall, 18 (30%), 13 (22%), 23 (38%) and 19 (32%) patients presented with high expression of EGFR, HER-2, HER-3 and HER-4, respectively, and the co-expression of 2, 3 and all 4 members of the HER family was observed. High expression of EGFR and HER-4 was associated with distant metastasis. High HER-3 expression was significantly associated with an advanced Enneking stage and distant metastasis. Multivariate analysis demonstrated that the expression of EGFR, HER-3, HER-4, EGFR/HER-3, EGFR/HER-4 and HER-3/HER-4 was an independent predictor of poor PFS and OS time in osteosarcoma patients with stage I–IIB disease. In patients with stage IIB osteosarcoma, the expression of HER-4 and EGFR/HER-4 demonstrated a more significant effect on PFS and OS time. In conclusion, therapies targeting EGFR, HER-3 and HER-4 may provide promising strategies for primary osteosarcoma.

Engineered exosomes: A new promise for the management of musculoskeletal diseases

BACKGROUND

Exosomes are nanovesicles actively secreted by potentially all cell types, including tumour cells, with the primary role of extracellular systemic communication mediators, both at autocrine and paracrine levels, at short and long distances. Recently, different studies have used exosomes as a delivery system for a plethora of different molecules, such as drugs, microRNAs and proteins. This has been made possible thanks to the simplicity in exosomes engineering, their great stability and versatility for applications in oncology as well as in regenerative medicine.

SCOPE OF REVIEW

The aim of this review is to provide information on the state-of-the-art and possible applications of engineered exosomes, both for cargo and specific cell-targeting, in different pathologies related to the musculoskeletal system.

MAJOR CONCLUSIONS

The use of exosomes as therapeutic agents is rapidly evolving, different studies explore drug delivery with exosomes using different molecules, showing an enormous potential in various research fields such as oncology and regenerative medicine.

GENERAL SIGNIFICANCE

However, despite the significant progress made by the different studies carried out, currently, the use of exosomes is not a therapeutic reality for the considerable difficulties to overcome.

Disruption of ETV6 leads to TWIST1-dependent progression and resistance to epidermal growth factor receptor tyrosine kinase inhibitors in prostate cancer

BACKGROUND

ETS variant gene 6 (ETV6) is a putative tumor suppressor and repressed by epidermal growth factor receptor (EGFR) signaling in prostate cancer. Since EGFR antagonists seem ineffective in castration-resistant prostate cancer (CRPC), we aim to study the role of ETV6 in the development of drug resistance.

METHODS

Etv6 target gene was validated by ChIP and promoter reporter assays. Correlation of ETV6 and TWIST1 was analyzed in human clinical datasets and tissue samples. Migration, invasion, and metastasis assays were used to measure the cellular responses after perturbation of ETV6 -TWIST1 axis. Proliferation and tumor growth in xenograft model were performed to evaluate the drug sensitivities of EGFR-tyrosine kinase inhibitors (TKIs).

RESULTS

ETV6 inhibits TWIST1 expression and disruption of ETV6 promotes TWIST1-dependent malignant phenotypes. Importantly, ETV6 is required to the anti-proliferation effects of EGFR-TKIs, partly due to the inhibitory function of ETV6 on TWIST1. We also found that EGFR-RAS signaling is tightly controlled by ETV6, supporting its role in TKI sensitivity.

CONCLUSIONS

Our study demonstrates that disruption of ETV6 contributes to EGFR-TKI resistance, which is likely due to derepression of TWIST1 and activation of EGFR-RAS signaling. Our results implicate ETV6 as a potential marker for predicting efficacy of an EGFR-targeted anticancer approach. Combination treatment of TWIST1 inhibitors could sensitize the anti-proliferation effects of EGFR-TKIs.

The PCAT3/PCAT9-miR-203-SNAI2 axis functions as a key mediator for prostate tumor growth and progression

Long non-coding RNAs (lncRNAs) have been reported to be of great importance in the formation and progression of a wide range of human carcinomas including prostate cancer (PCa). Among them, PCAT3 and PCAT9 have been identified as two prostate tissue-specific lncRNAs and are up-regulated in PCa. However, their roles in the biological characteristics of PCa have not been fully elucidated. In the present study, our data revealed that knockdown of PCAT3 and PCAT9 suppressed cellular proliferation, invasion, migration, angiogenesis and stemness in androgen-dependent LNCaP and 22Rv1 cells. Strikingly, bioinformatics analysis predicted that both PCAT3 and PCAT9 transcripts had two conserved binding sties for miR-203. Meanwhile, dual luciferase report assays revealed that miR-203 could suppress the luciferase activities of reporter plasmids carrying the binding site of miR-203 on the mRNA of PCAT3 or PCAT9. Quantitative RT-PCR (qRT-PCR) and RNA fluorescence in situ hybridization (RNA-FISH) showed that miR-203 mimic reduced the expression of PCAT3 and PCAT9 both in LNCaP and 22Rv1 cells. We also noted that both PCAT3 and PCAT9 inhibited miR-203 expression and alleviated repression on the expression of SNAI2, a critical regulator of epithelial-mesenchymal transition directly targeted by miR-203. Functionally, silence of miR-203 or ectopic expression of SNAI2 attenuated the inhibitory effect of PCAT3 and PCAT9 knockdown on cell proliferation and migration in vitro, and xenograft growth in vivo. Taken together, our data suggested that the PCAT3/PCAT9-miR-203-SNAI2 axis may serve as a promising diagnostic and therapeutic target for PCa.

Androgen receptor regulates SRC expression through microRNA-203

The SRC kinase has pivotal roles in multiple developmental processes and in tumor progression. An inverse relationship has been observed between androgen receptor (AR) activity and SRC signaling in advanced prostate cancer (PCa); however, the modulation of AR/SRC crosstalk that leads to metastatic PCa is unclear. Here, we showed that patients with high SRC levels displayed correspondingly low canonical AR gene signatures. Our results demonstrated that activated AR induced miR-203 and reduced SRC levels in PCa model systems. miR-203 directly binds to the 3′ UTR of SRC and regulates the stability of SRC mRNA upon AR activation. Moreover, we found that progressive PCa cell migration and growth were associated with a decrease in AR-regulated miR-203 and an increase in SRC. Relationships among AR, miR-203, and SRC were also confirmed in clinical datasets and specimens. We suggest that the induction of SRC results in increased PCa metastasis that is linked to the dysregulation of the AR signaling pathway through the inactivation of miR-203.

MicroRNA-421 regulated by HIF-1α promotes metastasis, inhibits apoptosis, and induces cisplatin resistance by targeting E-cadherin and caspase-3 in gastric cancer

Hypoxia and dysregulation of microRNAs (miRNAs) have been identified as crucial factors in carcinogenesis. However, the potential mechanisms of HIF-1α and miR-421 in gastric cancer have not been well elucidated. In this study, we found that miR-421 was up-regulated by HIF-1α. Overexpression of miR-421 promoted metastasis, inhibited apoptosis, and induced cisplatin resistance in gastric cancer in vivo and in vitro. E-cadherin and caspase-3 were identified as targets of miR-421. Besides, relative mRNA expression of miR-421 was significantly increased in gastric cancer tumor tissues compared with non-tumor tissues in a cohort of gastric cancer specimens (n=107). The expression of miR-421 was higher in advanced gastric cancers compared with localized ones. Moreover, Kaplan–Meier analysis illustrated that those patients with low levels of miR-421 had a significant longer overall survival (p = 0.006) and time to relapse (p = 0.007). Therefore, miR-421 could serve as an important prognostic marker and a potential molecular target for therapy in gastric cancer.

Implications of microRNA dysregulation in the development of prostate cancer

MicroRNAs (miRNAs) are non-coding small RNAs that target mRNA to reduce protein expression. They play fundamental roles in several diseases, including prostate cancer (PCa). A single miRNA can target hundreds of mRNAs and coordinately regulate them, which implicates them in nearly every biological pathway. Hence, miRNAs modulate proliferation, cell cycle, apoptosis, adhesion, migration, invasion and metastasis, most of them constituting crucial hallmarks of cancer. Due to these properties, miRNAs emerged as promising tools for diagnostic, prognosis and management of cancer patients. Moreover, they come out as potential targets for cancer treatment, and several efforts are being made to progress in the field of miRNA-based cancer therapy. In this review, we will summarize the recent information about miRNAs in PCa. We will recapitulate all the miRNAs involved in the androgen pathway and the biology of PCa, focusing in PCa initiation and progression. In particular, we will describe the miRNAs associated with cell proliferation, cell cycle and apoptosis in PCa, as well as invasion, adhesion and metastatic miRNAs. We will revise the recent progress made understanding the role of circulating miRNAs identified in PCa that might be useful for PCa patient stratification. Another key aspect to be discussed in this review is miRNAs’ role in PCa therapy, including the miRNAs delivery.

Polyisoprenylated cysteinyl amide inhibitors induce caspase 3/7- and 8-mediated apoptosis and inhibit migration and invasion of metastatic prostate cancer cells

Metastatic castration-resistant prostate cancer (mCRPC) is the most aggressive and deadly form of prostate cancer. It is characterized by the overexpression of epidermal growth factor receptors whose signals are mediated by small monomeric G proteins of the Ras superfamily. These require polyisoprenylation for functional activity. Polyisoprenylated cysteinyl amide inhibitors (PCAIs) of polyisoprenylated methylated protein methyl esterase (PMPMEase) were developed as potential targeted therapies to mitigate excessive growth signaling in mCRPC either by inhibiting PMPMEase and/or perturbing the polyisoprenylation-dependent functional interactions. We investigated the effects of PCAIs on the viability of prostate cancer PC 3, DU 145, MDA PCa 2b, LNCaP and 22Rv1 cells, determined the effect of the PCAIs on PC 3 cell proliferation, survival and caspase-mediated apoptotic cell death. Metastatic PC 3 and DU 145 cell migration and invasion in the presence of NSL-BA-040 were determined using the scratch and matrigel invasion assays. We further investigated the effect of NSL-BA-040 on F-actin organization in TagRFP F-actin marker-transfected metastatic PC 3 cells. The PCAIs suppress mCRPC cell viability with EC₅₀ values ranging from 1.3 to 4.0 µM for the most potent of the PCAIs against PC 3, DU 145, MDA PCa 2b, LNCaP and 22Rv cells. PCAIs induced apoptotic cell death in PC 3 and DU 145 cells as determined by annexin V/propidium iodide flow cytometry analysis through the activation of caspases 3 and 8 while also inhibiting migration and invasion through the disruption of F-actin organization. Taken together, our studies show the anti-cancer effects on mCRPC cells through induction of caspase-mediated apoptosis and F-actin-mediated inhibition of cell motility and invasion thereby indicating the anti-tumor and anti-metastatic potential of the PCAIs.

MicroRNA Signature of Lung Adenocarcinoma with EGFR Exon 19 Deletion

The findings of EGFR mutations and the development of targeted therapies have significantly improved the overall survival of lung cancer patients. Still, the prognosis remains poor, so we need to know more about the genetic alterations in lung cancer. MicroRNAs are dysregulated in lung cancer, and some of them can regulate EGFR. So it is very important to predict the candidate microRNAs that target mutated EGFR and to investigate the role of these candidate microRNAs in lung cancer. In this study, we investigated the difference of microRNAs expression between lung adenocarcinoma cell lines with EGFR exon 19 deletion (H1650 and PC9) and wild-type (H1299 and A549) using the Phalanx Human Whole Genome Microarray. Then the expression of individual microRNAs was validated by qRT-PCR assays. Moreover, we detected the microRNAs expression in plasma of lung adenocarcinoma patients with EGFR exon 19 deletion and wild-type. Lastly, we explored the function of the positive microRNA in EGFR tyrosine kinase inhibitors (EGFR-TKIs ) resistance using MTT and Annexin V-APC assays. The expression of 1,732 microRNAs was evaluated, and we found that microRNAs expression was different between these two groups. Hsa-miR-141-3p, hsa-miR-200c-3p, hsa-miR-203, hsa-miR-3182, hsa-miR-934 were up-regulated and hsa-miR-3196 was down-regulated in the EGFR exon 19 deletion group compared with wild-type group. The detection of circulating microRNAs showed that miR-3196 was down-regulated in lung adenocarcinoma patients with EGFR exon 19 deletion compared with wild-type. And then the MTT assay results showed that miR-3196 had no effect on the sensitivity of erlotinib. The results of apoptosis analysis showed that inhibition of miR-3196 and erlotinib induced more apoptosis in H1299 cells than erlotinib alone, and overexpressed miR-3196 and erlotinib induced less apoptosis in PC9 cells than erlotinib alone (P<0.05). It is suggested that microRNAs associate with EGFR exon 19 deletion and miR-3196 may be further explored as a potential predictor and targeted biomarker when it is difficult to get the tumors.

Deciphering the function of non-coding RNAs in prostate cancer

The advent of next-generation sequencing methods is fuelling the discovery of multiple non-coding RNA transcripts with direct implication in cell biology and homeostasis. This new layer of biological regulation seems to be of particular importance in human pathogenesis, including cancer. The aberrant expression of ncRNAs is a feature of prostate cancer, as they promote tumor-suppressive or oncogenic activities, controlling multicellular events leading to carcinogenesis and tumor progression. From the small RNAs involved in the RNAi pathway to the long non-coding RNAs controlling chromatin remodeling, alternative splicing, and DNA repair, the non-coding transcriptome represents the significant majority of transcriptional output. As such, ncRNAs appear as exciting new diagnostic, prognostic, and therapeutic tools. However, additional work is required to characterize the RNA species, their functions, and their applicability to clinical practice in oncology. In this review, we summarize the most important features of ncRNA biology, emphasizing its relevance in prostate carcinogenesis and its potential for clinical applications.

A function-blocking CD47 antibody suppresses stem cell and EGF signaling in triple-negative breast cancer

CD47 is a signaling receptor for thrombospondin-1 and the counter-receptor for signal-regulatory protein-α (SIRPα). By inducing inhibitory SIRPα signaling, elevated CD47 expression by some cancers prevents macrophage phagocytosis. The anti-human CD47 antibody B6H12 inhibits tumor growth in several xenograft models, presumably by preventing SIRPα engagement. However, CD47 signaling in nontransformed and some malignant cells regulates self-renewal, suggesting that CD47 antibodies may therapeutically target cancer stem cells (CSCs). Treatment of MDA-MB-231 breast CSCs with B6H12 decreased proliferation and asymmetric cell division. Similar effects were observed in T47D CSCs but not in MCF7 breast carcinoma or MCF10A breast epithelial cells. Gene expression analysis in breast CSCs treated with B6H12 showed decreased expression of epidermal growth factor receptor (EGFR) and the stem cell transcription factor KLF4. EGFR and KLF4 mRNAs are known targets of microRNA-7, and B6H12 treatment correspondingly enhanced microRNA-7 expression in breast CSCs. B6H12 treatment also acutely inhibited EGF-induced EGFR tyrosine phosphorylation. Expression of B6H12-responsive genes correlated with CD47 mRNA expression in human breast cancers, suggesting that the CD47 signaling pathways identified in breast CSCs are functional in vivo. These data reveal a novel SIRPα-independent mechanism by which therapeutic CD47 antibodies could control tumor growth by autonomously forcing differentiation of CSC.

Epidermal growth factor receptor signaling promotes metastatic prostate cancer through microRNA-96-mediated downregulation of the tumor suppressor ETV6

It has been suggested that ETV6 serves as a tumor suppressor; however, its molecular regulation and cellular functions remain unclear. We used prostate cancer as a model system and demonstrated a molecular mechanism in which ETV6 can be regulated by epidermal growth factor receptor (EGFR) signaling through microRNA-96 (miR-96)-mediated downregulation. In addition, EGFR acts as a transcriptional coactivator that binds to the promoter of primary miR-96 and transcriptionally regulates miR-96 levels. We analyzed two sets of clinical prostate cancer samples, confirmed association patterns that were consistent with the EGFR-miR-96-ETV6 signaling model and demonstrated that the reduced ETV6 levels were associated with malignant prostate cancer. Based on results derived from multiple approaches, we identified the biological functions of ETV6 as a tumor suppressor that inhibits proliferation and metastasis in prostate cancer. We present a molecular mechanism in which EGFR activation leads to the induction of miR-96 expression and suppression of ETV6, which contributes to prostate cancer progression.

KLF4 functions as an activator of the androgen receptor through reciprocal feedback

In prostate cancer, Krüppel-like factor 4 (KLF4) depletion occurs frequently, suggesting a role as suppressor tumor. KLF4 is a transcription factor associated with androgen receptor (AR) expression; however, its cellular functions and signaling regulation mechanism remain largely unknown. In this study, we demonstrated that activated AR binds to the KLF4 promoter and enhances KLF4 expression, which reciprocally targets the AR promoter, thus sustaining KLF4 activity. Ectopic KLF4 expression in androgen-independent prostate cancer cells induced AR expression and decreased cell proliferation, invasion and bone metastasis. We previously showed that increased microRNA (miR)-1 expression is associated with reduced bone metastasis of prostate cancer cells. Here we observed that KLF4 targets the primary miR-1-2 stem-loop promoter and stimulates miR-1 expression. In clinical prostate cancer specimens, KLF4 levels were positively correlated with miR-1 and AR levels. These data suggest that the loss of KLF4 expression is one mechanistic link between aggressive prostate cancer progression and low canonical AR output through miR-1 inactivation.

Downregulation of Potential Tumor Suppressor miR-203a by Promoter Methylation Contributes to the Invasiveness of Gastric Cardia Adenocarcinoma

Like many tumor suppressor genes, some miRNA genes harboring CpG islands undergo methylation-mediated silencing. In the study, we found significant downregulation and proximal promoter methylation of miR-203a and miR-203b in gastric cardia adenocarcinoma (GCA) tissues. The methylation status of miR-203a and miR-203b in tumor tissues was negatively correlated with their expression level. GCA patients in stage III and IV with reduced expression or hypermethylation of miR-203a demonstrated poor patient survival. In all, miR-203a and miR-203b may function as tumor suppressive miRNAs, and reactivation of miR-203a may have therapeutic potential and may be used as prognostic marker for GCA patients.

EGF receptor ligands: recent advances

Seven ligands bind to and activate the mammalian epidermal growth factor (EGF) receptor (EGFR/ERBB1/HER1): EGF, transforming growth factor-alpha (TGFA), heparin-binding EGF-like growth factor (HBEGF), betacellulin (BTC), amphiregulin (AREG), epiregulin (EREG), and epigen (EPGN). Of these, EGF, TGFA, HBEGF, and BTC are thought to be high-affinity ligands, whereas AREG, EREG, and EPGN constitute low-affinity ligands. This focused review is meant to highlight recent studies related to actions of the individual EGFR ligands, the interesting biology that has been uncovered, and relevant advances related to ligand interactions with the EGFR.

hsa-miR-135a-1 inhibits prostate cancer cell growth and migration by targeting EGFR

Prostate cancer is one of the leading causes of death in men worldwide. Differentially expressed microRNAs (miRNAs) are associated with metastatic prostate cancer. However, their potential roles for affecting prostate cancer initiation and progression remain largely unknown. Here, we examined the aberrant expression profiles of miRNAs in human metastatic prostate cancer tissues. We further validated our miRNA expression data using two large, independent clinical prostate cancer datasets from the Memorial Sloan Kettering Cancer Center (MSKCC) and The Cancer Genome Atlas (TCGA). Our data support a model in which hsa-miR-135-1 acts as a potential tumor suppressor in metastatic prostate cancer. First, its downregulation was positively correlated with late TNM stage, high Gleason score, and adverse prognosis. Second, cell growth, cell cycle progression, cell migration and invasion, and xenograft tumor formation were dramatically inhibited by miR-135a overexpression. Third, in the microarray gene expression data analysis using Gene Set Enrichment Analysis (GSEA), Database for Annotation, Visualization and Integrated Discovery (DAVID) analysis, Ingenuity Pathway Analysis (IPA), and Oncomine concept analysis, we showed that miR-135a targets multiple oncogenic pathways including epidermal growth factor receptor (EGFR), which we verified using functional experimental assays. These results help advance our understanding of the function of miRNAs in metastatic prostate cancer and provide a basis for further clinical investigation.

Dissecting the role of microRNAs in prostate cancer metastasis: implications for the design of novel therapeutic approaches

Metastatic prostate cancer is a lethal disease that remains incurable despite the recent approval of new drugs, thus making the development of alternative treatment approaches urgently needed. A more precise understanding of the molecular mechanisms underlying prostate cancer dissemination could lead to the identification of novel therapeutic targets for the design of efficient anti-metastatic strategies. MicroRNA (miRNAs) are endogenous, small non-coding RNA molecules acting as key regulators of gene expression at post-transcriptional level. It has been clearly established that altered miRNA expression is a common hallmark of cancer. In addition, emerging evidence suggests their direct involvement in the metastatic cascade. In this review, we present a comprehensive overview of the data generated in experimental tumor models indicating that specific miRNAs may impinge on the different stages of prostate cancer metastasis, including (i) the regulation of epithelial-to-mesenchymal transition and cell migration/invasion, (ii) the interplay between cancer cells and the surrounding stroma, (iii) the control of angiogenesis, (iv) the regulation of anoikis, and (v) the colonization of distant organs. Moreover, we show preliminary evidence of the clinical relevance of some of these miRNAs, in terms of association with tumor aggressiveness/dissemination and clinical outcome, as emerged from translation studies carried out in prostate cancer patient cohorts. We also discuss the potential and the current limitations of manipulating metastasis-related miRNAs, by mimicking or inhibiting them, as a strategy for the development of novel therapeutic approaches for the advanced disease.

Understanding the CREB1-miRNA feedback loop in human malignancies

cAMP response element binding protein 1 (CREB1, CREB) is a key transcription factor that mediates transcriptional responses to a variety of growth factors and stress signals. CREB1 has been shown to play a critical role in development and progression of tumors. MicroRNAs (miRNAs) are a class of non-coding RNAs. They post-transcriptionally regulate gene expression through pairing with the 3'-UTR of their target mRNAs and thus regulate initiation and progression of various types of human cancers. Recent studies have demonstrated that a number of miRNAs can be transcriptionally regulated by CREB1. Interestingly, CREB1 expression can also be modulated by miRNAs, thus forming a feedback loop. This review outlines the functional roles of CREB1, miRNA, and their interactions in human malignancies. This will help to define a relationship between CREB1 and miRNA in human cancer and develop novel therapeutic strategies.

Novel roles of androgen receptor, epidermal growth factor receptor, TP53, regulatory RNAs, NF-kappa-B, chromosomal translocations, neutrophil associated gelatinase, and matrix metalloproteinase-9 in prostate cancer and prostate cancer stem cells

Approximately one in six men will be diagnosed with some form of prostate cancer in their lifetime. Over 250,000 men worldwide die annually due to complications from prostate cancer. While advancements in prostate cancer screening and therapies have helped in lowering this statistic, better tests and more effective therapies are still needed. This review will summarize the novel roles of the androgen receptor (AR), epidermal growth factor receptor (EGFR), the EGFRvIII variant, TP53, long-non-coding RNAs (lncRNAs), microRNAs (miRs), NF-kappa-B, chromosomal translocations, neutrophil associated gelatinase, (NGAL), matrix metalloproteinase-9 (MMP-9), the tumor microenvironment and cancer stem cells (CSC) have on the diagnosis, development and treatment of prostate cancer.

MiRNA-203 Reduces Nasopharyngeal Carcinoma Radioresistance by Targeting IL8/AKT Signaling

Radioresistance poses a major challenge in nasopharyngeal carcinoma (NPC) treatment, but little is known about how miRNA (miR) regulates this phenomenon. In this study, we investigated the function and mechanism of miR-203 in NPC radioresistance, one of downregulated miRs in the radioresistant NPC cells identified by our previous microarray analysis. We observed that miR-203 was frequently downregulated in the radioresistant NPC tissues compared with radiosensitive NPC tissues, and its decrement significantly correlated with NPC radioresistance and poor patient survival, and was an independent predictor for reduced patient survival. In vitro radioresponse assays showed that miR-203 mimic markedly decreased NPC cell radioresistance. In a mouse model, therapeutic administration of miR-203 agomir dramatically sensitized NPC xenografts to irradiation. Mechanistically, we confirmed that IL8 was a direct target of miR-203, and found that reduced miR-203 promoted NPC cell radioresistance by activating IL8/AKT signaling. Moreover, the levels of IL8 and phospho-AKT were significantly increased in the radioresistant NPC tissues compared with radiosensitive NPC tissues, and negatively associated with miR-203 level. Our data demonstrate that miR-203 is a critical determinant of NPC radioresponse, and its decrement enhances NPC radioresistance through targeting IL8/AKT signaling, highlighting the therapeutic potential of the miR-203/IL8/AKT signaling axis in NPC radiosensitization.

MicroRNAs and Growth Factors: An Alliance Propelling Tumor Progression

Tumor progression requires cancer cell proliferation, migration, invasion, and attraction of blood and lymph vessels. These processes are tightly regulated by growth factors and their intracellular signaling pathways, which culminate in transcriptional programs. Hence, oncogenic mutations often capture growth factor signaling, and drugs able to intercept the underlying biochemical routes might retard cancer spread. Along with messenger RNAs, microRNAs play regulatory roles in growth factor signaling and in tumor progression. Because growth factors regulate abundance of certain microRNAs and the latter modulate the abundance of proteins necessary for growth factor signaling, the two classes of molecules form a dense web of interactions, which are dominated by a few recurring modules. We review specific examples of the alliance formed by growth factors and microRNAs and refer primarily to the epidermal growth factor (EGF) pathway. Clinical applications of the crosstalk between microRNAs and growth factors are described, including relevance to cancer therapy and to emergence of resistance to specific drugs.

EGF Receptor Promotes Prostate Cancer Bone Metastasis by Downregulating miR-1 and Activating TWIST1

Dysregulation of the EGFR signaling axis enhances bone metastases in many solid cancers. However, the relevant downstream effector signals in this axis are unclear. miR-1 was recently shown to function as a tumor suppressor in prostate cancer cells, where its expression correlated with reduced metastatic potential. In this study, we demonstrated a role for EGFR translocation in regulating transcription of miR-1-1, which directly targets expression of TWIST1. Consistent with these findings, we observed decreased miR-1 levels that correlated with enhanced expression of activated EGFR and TWIST1 in a cohort of human prostate cancer specimens and additional datasets. Our findings support a model in which nuclear EGFR acts as a transcriptional repressor to constrain the tumor-suppressive role of miR-1 and sustain oncogenic activation of TWIST1, thereby leading to accelerated bone metastasis.

miR-203 inhibition of renal cancer cell proliferation, migration and invasion by targeting of FGF2

BACKGROUND

Renal cell carcinoma (RCC) is one of the leading causes of cancer related mortality worldwide. Increasing evidence has shown that microRNAs function as oncogenes or tumor suppressors in human malignancies, but the roles of miR-203 in human RCC is still unclear.

METHODS

First, quantitative real-time PCR (qRT-PCR) was performed to detect miR-203 expression in renal cancer cell lines and clear cell RCC (ccRCC) specimens. Then, the association of miR-203 expression with clinicopathological features and survival was later analyzed. Finally, the roles of miR-203 in regulation of tumor proliferation, migration, invasion, and target gene expression were further investigated.

RESULTS

Our study showed miR-203 was down-regulated in renal cancer cell lines and ccRCC specimens (P < 0.05). Respectively, the low miR-203 expression in ccRCC specimens was associated with advanced clinical features and poorer prognosis (P < 0.05). miR-203 expression was an independent prognostic marker of overall ccRCC patient survival in a multivariate analysis (P < 0.05). Transient forced expression of miR-203 inhibited renal cancer cell growth and metastasis (P < 0.05). In contrast, down-regulation of miR-203 expression promoted renal cancer cell growth and metastasis (P < 0.05). Mechanistic investigations confirmed FGF2 as a direct target of miR-203, and up-regulation of miR-203 could decrease expression of FGF2. Further investigation showed that ectopic expression of FGF2 partially reversed the inhibition effect of enforced miR-203 expression on the malignant phenotypes of renal cancer cells.

CONCLUSIONS

Our study suggested that miR-203 could be a potential prognostic marker and functions as a tumor suppressor in human renal cancer by post-transcriptionally targeting FGF2.

VIRTUAL SLIDES

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/6828145701534108 .