Mir143 expression inversely correlates with nuclear ERK5 immunoreactivity in clinical prostate cancer

Integrating single-cell and bulk RNA sequencing to predict prognosis and immunotherapy response in prostate cancer

Prostate cancer (PCa) stands as a prominent contributor to morbidity and mortality among males on a global scale. Cancer-associated fibroblasts (CAFs) are considered to be closely connected to tumour growth, invasion, and metastasis. We explored the role and characteristics of CAFs in PCa through bioinformatics analysis and built a CAFs-based risk model to predict prognostic treatment and treatment response in PCa patients. First, we downloaded the scRNA-seq data for PCa from the GEO. We extracted bulk RNA-seq data for PCa from the TCGA and GEO and adopted "ComBat" to remove batch effects. Then, we created a Seurat object for the scRNA-seq data using the package "Seurat" in R and identified CAF clusters based on the CAF-related genes (CAFRGs). Based on CAFRGs, a prognostic model was constructed by univariate Cox, LASSO, and multivariate Cox analyses. And the model was validated internally and externally by Kaplan-Meier analysis, respectively. We further performed GO and KEGG analyses of DEGs between risk groups. Besides, we investigated differences in somatic mutations between different risk groups. We explored differences in the immune microenvironment landscape and ICG expression levels in the different groups. Finally, we predicted the response to immunotherapy and the sensitivity of antitumour drugs between the different groups. We screened 4 CAF clusters and identified 463 CAFRGs in PCa scRNA-seq. We constructed a model containing 10 prognostic CAFRGs by univariate Cox, LASSO, and multivariate Cox analysis. Somatic mutation analysis revealed that TTN and TP53 were significantly more mutated in the high-risk group. Finally, we screened 31 chemotherapeutic drugs and targeted therapeutic drugs for PCa. In conclusion, we identified four clusters based on CAFs and constructed a new CAFs-based prognostic signature that could predict PCa patient prognosis and response to immunotherapy and might suggest meaningful clinical options for the treatment of PCa.

Clinical Significance and Regulation of ERK5 Expression and Function in Cancer

Extracellular signal-regulated kinase 5 (ERK5) is a unique kinase among MAPKs family members, given its large structure characterized by the presence of a unique C-terminal domain. Despite increasing data demonstrating the relevance of the ERK5 pathway in the growth, survival, and differentiation of normal cells, ERK5 has recently attracted the attention of several research groups given its relevance in inflammatory disorders and cancer. Accumulating evidence reported its role in tumor initiation and progression. In this review, we explore the gene expression profile of ERK5 among cancers correlated with its clinical impact, as well as the prognostic value of ERK5 and pERK5 expression levels in tumors. We also summarize the importance of ERK5 in the maintenance of a cancer stem-like phenotype and explore the major known contributions of ERK5 in the tumor-associated microenvironment. Moreover, although several questions are still open concerning ERK5 molecular regulation, different ERK5 isoforms derived from the alternative splicing process are also described, highlighting the potential clinical relevance of targeting ERK5 pathways.

The Clinical Significance Of Circulating Mir-21, Mir-142, Mir-143, And Mir-146a In Patients With Prostate Cancer

Background

Prostate cancer (PCa) is the most common type of solid tissue cancer among men in western countries. In this study, we determined the levels of circulating miR-21, miR-142, miR-143, miR-146a, and RNU 44 levels as controls for early diagnosis of PCa.

Methods

The circulating miRNA levels in peripheral blood samples from 43 localized PCa patients, 12 metastatic PCa (MET) patients, and a control group of, 42 benign prostate hyperplasia (BPH) patients with a total of 97 volunteers were determined the by PCR method.

Results

No differences in the DCT values were found among the groups. In PCa and PCaMet groups the expression of miR21 and miR142 were higher compared to the BHP group. No other differences were observed among the other groups. miR21 expression in the PCa group was 6.29 folds upregulated whereas in the PCaMet group 10.84 folds up-regulated. When the total expression of miR142 is evaluated, it showed a positive correlation with mir21 and mir 146 (both p<0.001). Also, the expression of miR146 shows a positive correlation with both miR21 and miR143 (both p<0.001). Expression of miRNAs was found to be an independent diagnostic factor in patients with Gleason score, PSA, and free PSA levels.

Conclusions

Our study showed that co-expression of miR21, miR-142, miR-143, and miR-146a and the upregulation of miR-21 resulted in increased prostate carcinoma cell growth. In the PCaMet group, miR21 is the most upregulated of all miRNAs. These markers may provide a novel diagnostic tool to help diagnose PCa with aggressive behavior.

Small molecule ERK5 kinase inhibitors paradoxically activate ERK5 signalling: be careful what you wish for…

ERK5 is a protein kinase that also contains a nuclear localisation signal and a transcriptional transactivation domain. Inhibition of ERK5 has therapeutic potential in cancer and inflammation and this has prompted the development of ERK5 kinase inhibitors (ERK5i). However, few ERK5i programmes have taken account of the ERK5 transactivation domain. We have recently shown that the binding of small molecule ERK5i to the ERK5 kinase domain stimulates nuclear localisation and paradoxical activation of its transactivation domain. Other kinase inhibitors paradoxically activate their intended kinase target, in some cases leading to severe physiological consequences highlighting the importance of mitigating these effects. Here, we review the assays used to monitor ERK5 activities (kinase and transcriptional) in cells, the challenges faced in development of small molecule inhibitors to the ERK5 pathway, and classify the molecular mechanisms of paradoxical activation of protein kinases by kinase inhibitors.

MicroRNAs as Epigenetic Determinants of Treatment Response and Potential Therapeutic Targets in Prostate Cancer

Prostate cancer (PCa) is the second most common tumor in men worldwide, and the fifth leading cause of male cancer-related deaths in western countries. PC is a very heterogeneous disease, meaning that optimal clinical management of individual patients is challenging. Depending on disease grade and stage, patients can be followed in active surveillance protocols or undergo surgery, radiotherapy, hormonal therapy, and chemotherapy. Although therapeutic advancements exist in both radiatiotherapy and chemotherapy, in a considerable proportion of patients, the treatment remains unsuccessful, mainly due to tumor poor responsiveness and/or recurrence and metastasis. microRNAs (miRNAs), small noncoding RNAs that epigenetically regulate gene expression, are essential actors in multiple tumor-related processes, including apoptosis, cell growth and proliferation, autophagy, epithelial-to-mesenchymal transition, invasion, and metastasis. Given that these processes are deeply involved in cell response to anti-cancer treatments, miRNAs have been considered as key determinants of tumor treatment response. In this review, we provide an overview on main PCa-related miRNAs and describe the biological mechanisms by which specific miRNAs concur to determine PCa response to radiation and drug therapy. Additionally, we illustrate whether miRNAs can be considered novel therapeutic targets or tools on the basis of the consequences of their expression modulation in PCa experimental models.

Synthetic MIR143-3p Suppresses Cell Growth in Rhabdomyosarcoma Cells by Interrupting RAS Pathways Including PAX3-FOXO1

Simple Summary

Rhabdomyosarcoma (RMS) is a soft tissue sarcoma with embryonal (ERMS) and alveoral (ARMS) features, most frequently found in children. ARMS has the worse prognosis due to the formation of the chimeric PAX3–FOXO1 gene. New therapies are needed for the treatment of ARMS. The aim of this study is to evaluate the anticancer effect of chemically-modified MIR143-3p#12 (CM-MIR143#12) on RMS. The ectopic expression of CM-MIR143#12 induced a cell growth suppression by silencing not only KRAS, AKT, and ERK but also the PAX3–FOXO1 chimeric gene, and KRAS networks could control the expression of chimeric PAX3–FOXO1 in ARMS cells. Moreover, CM-MIR143#12 also silenced NRAS mutant in ERMS RD cells. CM-MIR143#12 can be a new nucleic acid medicine for the treatment of RMS by impairing the RAS networks including PAX3–FOXO1.

Abstract

Rhabdomyosarcoma (RMS) is a soft tissue sarcoma most frequently found in children. In RMS, there are two major subtypes, embryonal RMS (ERMS) and alveolar RMS (ARMS). ARMS has the worse prognosis of the two owing to the formation of the chimeric PAX3–FOXO1 gene. A novel therapeutic method is required for treating ARMS. In our previous study, we found that the ectopic expression of chemically modified MIR143-3p#12 (CM-MIR143#12), which is RNase-resistant and shows the highest anti-proliferation activity among the synthesized MIR143 derivatives that were tested, induces significant cell growth suppression by targeting KRAS, AKT, and ERK in colorectal cancer cells. The expression of MIR143-3p in RMS was dramatically downregulated compared with that of normal tissue. Ectopic expression of CM-MIR143#12 in RMS cells resulted in a significant growth inhibitory effect through the induction of apoptosis and autophagy. Interestingly, we found that CM-MIR143#12 also silenced the expression of chimeric PAX3–FOXO1 directly and, using siR-KRAS or siR-AKT, that KRAS networks regulated the expression of PAX3–FOXO1 in ARMS cells. In ERMS harboring NRAS mutation, CM-MIR143#12 silenced mutated NRAS. These findings indicate that CM-MIR143#12 efficiently perturbed the RAS signaling pathway, including the ARMS-specific KRAS/PAX3–FOXO1 networks.

MicroRNAs: potential biomarkers for diagnosis and prognosis of different cancers

A thorough understanding of the tumor environment and underlying genetic factors helps in the better formulation of cancer management strategies. Availability of efficient diagnostic and prognostic biomarkers facilitates early detection and progression of the disease. MicroRNAs affect different biological processes participating in tumorigenesis through regulation of their target genes. An expanding list of unique RNAs and understanding of their regulatory role has opened up a new field in cancer research. Based on a comprehensive literature search, we identified 728 miRNAs dysregulated in sixteen cancer types namely bladder cancer (BC), breast cancer (BrC), cervical cancer (CC), colorectal cancer (CRC), esophageal cancer (EC), endometrial cancer (EnC), gastric cancer (GC), hepatocellular cancer (HCC), head and neck squamous cell cancer (HNSCC), lung cancer (LC), ovarian cancer (OC), pancreatic cancer (PC), prostate cancer (PrC), renal cell cancer (RCC), skin cancer (SC), and thyroid cancer (TC). Expression of 43 miRNAs was either upregulated or downregulated in six or more of these cancers. Finally, seven miRNAs namely mir-18a, mir-21, mir-143/145, mir-210, mir-218, mir-221, showing maximum dysregulation, either up- or down-regulation in the majority of cancers, were selected for a detailed presentation of their expression and evaluation of their potential as biomarkers in the diagnosis and prognosis of different cancers.

Beyond Kinase Activity: ERK5 Nucleo-Cytoplasmic Shuttling as a Novel Target for Anticancer Therapy

The importance of mitogen-activated protein kinases (MAPK) in human pathology is underlined by the relevance of abnormalities of MAPK-related signaling pathways to a number of different diseases, including inflammatory disorders and cancer. One of the key events in MAPK signaling, especially with respect to pro-proliferative effects that are crucial for the onset and progression of cancer, is MAPK nuclear translocation and its role in the regulation of gene expression. The extracellular signal-regulated kinase 5 (ERK5) is the most recently discovered classical MAPK and it is emerging as a possible target for cancer treatment. The bigger size of ERK5 when compared to other MAPK enables multiple levels of regulation of its expression and activity. In particular, the phosphorylation of kinase domain and C-terminus, as well as post-translational modifications and chaperone binding, are involved in ERK5 regulation. Likewise, different mechanisms control ERK5 nucleo-cytoplasmic shuttling, underscoring the key role of ERK5 in the nuclear compartment. In this review, we will focus on the mechanisms involved in ERK5 trafficking between cytoplasm and nucleus, and discuss how these processes might be exploited to design new strategies for cancer treatment.

Effect of Sulfated Polysaccharide from Undaria pinnatifida (SPUP) on Proliferation, Migration, and Apoptosis of Human Prostatic Cancer

Objective. To observe the effect of sulfated polysaccharide from Undaria pinnatifida (SPUP) on proliferation, migration, and apoptosis of human prostatic cancer. Methods. DU145 human prostate cancer cells were cultured in vitro, and the proliferation activity both in the control group and the SPUP treatment groups (25, 50, 100, 200 μg/ml) was measured by CCK-8 assay. The wound healing assay was conducted to detect the cell migration. Cell apoptosis was measured by flow cytometry. The protein and mRNA expressions of matrix metalloproteinase-9 (MMP-9) and apoptosis-related factor Bax were detected by qRT-PCR and Western blot. The expressions of cleaved caspase-3 and cleaved caspase-9 were also determined by Western blot. Results. (1) CCK-8 results showed that the proliferative activity of DU145 cells was significantly decreased with the increase of SPUP treatment concentration (P<0.05) in a dose-dependent manner and that the inhibitory effect of SPUP was most significant at 72 h (P<0.05) as compared with the control group; (2) the migration rate of SPUP-treated cells was significantly decreased (P<0.05) as compared with the control group. And the results of qRT-PCR and Western blot assays showed that SPUP inhibited the expression of MMP-9 in DU145 cells; (3) compared with the control group, the SPUP-treated groups had increased apoptosis of the cells. The expressions of apoptosis-related factors cleaved caspase-3, cleaved caspase-9, and Bax were upregulated (P<0.05), and the mRNA expression of Bax was increased (P<0.05). Conclusion. SPUP showed an antitumor activity in prostatic cancer, and the underlying mechanism may be pertaining to inhibition of migration, proliferation, and induction of apoptosis of cancer cells.

Role of MicroRNAs in Treatment Response in Prostate Cancer

Prostate cancer (PCa) is the most common non-skin cancer in men worldwide, resulting in significant mortality and morbidity. Depending on the grade and stage of the cancer, patients may be given radiation therapy, hormonal therapy, or chemotherapy. However, more than half of these patients develop resistance to treatment, leading to disease progression and metastases, often with lethal consequences. MicroRNAs (miRNAs) are short, non-coding RNAs, which regulate numerous physiological as well as pathological processes, including cancer. miRNAs mediate their regulatory effect predominately by binding to the 3'-untranslated region (UTR) of their target mRNAs. In this review, we will describe the mechanisms by which miRNAs mediate resistance to radiation and drug therapy (i.e. hormone therapy and chemotherapy) in PCa, including control of apoptosis, cell growth and proliferation, autophagy, epithelial-to-mesenchymal transition (EMT), invasion and metastasis, and cancer stem cells (CSCs). Furthermore, we will discuss the utility of circulating miRNAs isolated from different body fluids of prostate cancer patients as non-invasive biomarkers of cancer detection, disease progression, and therapy response. Finally, we will shortlist the candidate miRNAs, which may have a role in drug and radioresistance, that could potentially be used as predictive biomarkers of treatment response.

Impact of ERK5 on the Hallmarks of Cancer

Extracellular signal-regulated kinase 5 (ERK5) belongs to the mitogen-activated protein kinase (MAPK) family that consists of highly conserved enzymes expressed in all eukaryotic cells and elicits several biological responses, including cell survival, proliferation, migration, and differentiation. In recent years, accumulating lines of evidence point to a relevant role of ERK5 in the onset and progression of several types of cancer. In particular, it has been reported that ERK5 is a key signaling molecule involved in almost all the biological features of cancer cells so that its targeting is emerging as a promising strategy to suppress tumor growth and spreading. Based on that, in this review, we pinpoint the hallmark-specific role of ERK5 in cancer in order to identify biological features that will potentially benefit from ERK5 targeting.

Anti-cancer Effects of a Chemically Modified miR-143 on Bladder Cancer by Either Systemic or Intravesical Treatment

We developed a novel chemically modified miR-143 (miR-143#12), and with it we investigated the contribution of miR-143 to the pathogenesis of bladder cancer (BC), in which miR-143 is extremely downregulated. Since miR-143 silenced K-RAS and RAS effector-signaling molecules Erk and Akt, we performed the ectopic expression of miR-143 in human BC 253J-BV cells, and we examined the growth inhibition and the mechanism of it in vitro and in orthotopic model mice. As a result, miR-143#12 induced a marked growth inhibition with apoptosis through impairing RAS-signaling networks, including SOS1, which exchanges guanosine diphosphate (GDP)/RAS for active guanosine triphosphate (GTP)/RAS. In the in vivo study, miR-143#12 exhibited a marked anti-tumor activity by either systemic or intravesical administration with polyionic copolymer (PIC) as the carrier, compared with the activity obtained by use of lipofection. These findings raised the possibility that the chemically modified miR-143#12 would be a candidate of microRNA (miRNA) medicine for BC delivered by intravesical infusion.

The role of microRNAs in prostate cancer migration, invasion, and metastasis

Prostate cancer (PCa) is considered the most prevalent malignancy and the second major cause of cancer-related death in males from Western countries. PCa exhibits variable clinical pictures, ranging from dormant to highly metastatic cancer. PCa suffers from poor prognosis and diagnosis markers, and novel biomarkers are required to define disease stages and to design appropriate therapeutic approach by considering the possible genomic and epigenomic differences. MicroRNAs (miRNAs) comprise a class of small noncoding RNAs, which have remarkable functions in cell formation, differentiation, and cancer development and contribute in these processes through controlling the expressions of protein-coding genes by repressing translation or breaking down the messenger RNA in a sequence-specific method. miRNAs in cancer are able to reflect informative data about the current status of disease and this might benefit PCa prognosis and diagnosis since that is concerned to PCa patients and we intend to highlight it in this paper.

Anti-tumor activity and the mechanism of a green tea (Camellia sinensis) polysaccharide on prostate cancer

In this study, a homogeneous polysaccharide (GTP), with a molecular weight of 7.0 × 10⁴ Da, was isolated from Green tea, which was only composed of glucose. The antitumor effects of GTP on prostate cancer (PC) cell line along with the possible mechanism was examined. First, we investigate the potential role of microRNA-93 (miR-93) in PC progression. Our results showed that miR-93 was significantly upregulated in human PC tissues and several PC cell lines, and its overexpression was correlated with poor survival in PC patients. Furthermore, functional analysis showed that miR-93 overexpression promoted the migration, invasion and proliferation of PC-3 cells transfected with miR-93 mimics, while its knockdown displayed an opposite result in DU145 cells following miR-93 inhibitor transfection. Additionally, in vivo tumorigenic studies on nude mice confirmed that miR-93 mimic treatment accelerated the growth of PC-3 xenograft tumors. As expected, GTP (25, 50 and 100 μg/ml) inhibited growth of PC-3 cells via inducing apoptosis, which was achieved by elevation of bax/bcl-2 ratio and caspae-3 protein expression, as well as a decrease of miR-93. Thus, miR-93 may be a potential therapeutic target by GTP for PC therapy.

MicroRNA-143 targets ERK5 in granulopoiesis and predicts outcome of patients with acute myeloid leukemia

Hematopoiesis, the formation of blood cells from hematopoietic stem cells (HSC), is a highly regulated process. Since the discovery of microRNAs (miRNAs), several studies have shown their significant role in the regulation of the hematopoietic system. Impaired expression of miRNAs leads to disrupted cellular pathways and in particular causes loss of hematopoietic ability. Here, we report a previously unrecognized function of miR-143 in granulopoiesis. Hematopoietic cells undergoing granulocytic differentiation exhibited increased miR-143 expression. Overexpression or ablation of miR-143 expression resulted in accelerated granulocytic differentiation or block of differentiation, respectively. The absence of miR-143 in mice resulted in a reduced number of mature granulocytes in blood and bone marrow. Additionally, we observed an association of high miR-143 expression levels with a higher probability of survival in two different cohorts of patients with acute myeloid leukemia (AML). Overexpression of miR-143 in AML cells impaired cell growth, partially induced differentiation, and caused apoptosis. Argonaute2-RNA-Immunoprecipitation assay revealed ERK5, a member of the MAPK-family, as a target of miR-143 in myeloid cells. Further, we observed an inverse correlation of miR-143 and ERK5 in primary AML patient samples, and in CD34⁺ HSPCs undergoing granulocytic differentiation and we confirmed functional relevance of ERK5 in myeloid cells. In conclusion, our data describe miR-143 as a relevant factor in granulocyte differentiation, whose expression may be useful as a prognostic and therapeutic factor in AML therapy.

PART-1 functions as a competitive endogenous RNA for promoting tumor progression by sponging miR-143 in colorectal cancer

LncRNAs were altered in several cancers and played a crucial role in various biological activities and progressions of different diseases, including proliferation, chemical resistance, and metastasis. In the present study, we revealed that prostrate androgen-regulated transcript-1 (PART-1) was highly expressed in colorectal cancer cells and tissues, and knockdown of PART-1 suppressed cell proliferation and metastasis, both in vitro and in vivo. In addition, PART-1 functioned as a ceRNA of DNMT3A, by sponging miR-143. Finally,PART-1 induced tumor progression by regulating DNMT3A.

MicroRNA-143 suppresses oral squamous cell carcinoma cell growth, invasion and glucose metabolism through targeting hexokinase 2

miRNAs are non-coding RNAs that have functions to regulate gene expression and play essential roles in a variety of biological processes of cancers. In the present study, we report miR-143 acts as a tumor suppressor in human oral squamous cell carcinoma (OSCC). The expressions of miR-143 are down-regulated in both OSCC cell lines and patient samples compared with normal adjacent tissues. We found overexpression of miR-143 in oral cancer cell lines suppresses cell migration, cellular glucose metabolism and proliferation. Moreover, overexpression of miR-143 promoted apoptosis and significantly caused cell cycle arrest at G₁ stage. The colony formation of oral cancer cells was also suppressed by miR-143 We identified hexokinase 2 (HK2) as a direct target of miR-143 in oral cancer cells. Our data show that miR-143 complementary pairs to the 3'-UTR of HK2 in oral cancer cells, leading to the inhibition of glycolysis in vitro and in vivo Moreover, knockdown of HK2 by siRNA in oral cancer cells inhibited glucose metabolism, proliferation and migration. Recovery of glucose metabolism by overexpression of HK2 in miR-143 overexpressing cells restores the cell migration and proliferation, suggesting that the miR-143-mediated cancer suppression is through the direct inhibition of HK2. In summary, the present studies highlight miR-143 as a tumor suppressor in OSCC by the suppression of cell migration, glucose metabolism and proliferation through directly targeting HK2, rendering miR-143 a therapeutic strategy for the treatment of clinical OSCC patients.

MicroRNA-143 inhibits tumorigenesis in hepatocellular carcinoma by downregulating GATA6

MicroRNAs serve a critical role in human hepatocellular carcinoma (HCC) progression. However, the exact role of microRNA-143 (miR-143) in HCC remains unclear. The current study investigates the molecular mechanism of miR-143 in HCC. In cultured HepG2 and Bel7402 cell lines, miR-143 levels were raised by lentivirus transduction. This significantly inhibited HCC progression in terms of cell invasion and proliferation in both HepG2 and Bel7402 cell lines (P<0.05). MiR-143 also significantly decreased tumor implantation in vivo (P<0.05). Regulation of miR-143 on its direct target, GATA-binding factor 6 (GATA6), was investigated by multiple strategies, including dual-luciferase assay, quantitative polymerase chain reaction and western blot analysis. The results indicated that miR-143 was downregulated in both HCC cell lines and human tumors. GATA6 was identified as the downstream target of miR-143 in HCC, and overexpressing GATA6 was able to counter the tumor-suppressive effect of miR-143 on HCC in HepG2 and Bel7402 cells by significantly increasing proliferation and invasion rates (P<0.05). Therefore, a novel epigenetic pathway was identified in which miR-143 may suppress the malignancy of HCC by targeting GATA6.

A novel microRNA-1207-3p/FNDC1/FN1/AR regulatory pathway in prostate cancer

Prostate cancer (PCa) is the second most common cause of cancer-specific deaths in the U.S. Unfortunately, the underlying molecular mechanisms for its development and progression remain unclear. Studies have established that microRNAs (miRNAs) are dysregulated in PCa. The intron-derived microRNA-1207-3p (miR-1207-3p) is encoded at the non-protein coding gene locus PVT1 on the 8q24 human chromosomal region, an established PCa susceptibility locus. However, miR-1207-3p in PCa had not previously been investigated. Therefore, we explored if miR-1207-3p plays any regulatory role in PCa. We discovered that miR-1207-3p is significantly underexpressed in PCa cell lines in comparison to normal prostate epithelial cells, and that increased expression of microRNA-1207-3p in PCa cells significantly inhibits proliferation, migration, and induces apoptosis via direct molecular targeting of fibronectin type III domain containing 1 (FNDC1). Our studies also revealed significant overexpression of FNDC1, fibronectin (FN1) and the androgen receptor (AR) in human PCa cell lines as well as tissues, and FNDC1, FN1, and AR positively correlate with aggressive PCa. These findings, recently published in Experimental Cell Research, are the first to describe a novel miR-1207-3p/FNDC1/FN1/AR novel regulatory pathway in PCa.

ERK5 and Cell Proliferation: Nuclear Localization Is What Matters

ERK5, the last MAP kinase family member discovered, is activated by the upstream kinase MEK5 in response to growth factors and stress stimulation. MEK5-ERK5 pathway has been associated to different cellular processes, playing a crucial role in cell proliferation in normal and cancer cells by mechanisms that are both dependent and independent of its kinase activity. Thus, nuclear ERK5 activates transcription factors by either direct phosphorylation or acting as co-activator thanks to a unique transcriptional activation TAD domain located at its C-terminal tail. Consequently, ERK5 has been proposed as an interesting target to tackle different cancers, and either inhibitors of ERK5 activity or silencing the protein have shown antiproliferative activity in cancer cells and to block tumor growth in animal models. Here, we review the different mechanisms involved in ERK5 nuclear translocation and their consequences. Inactive ERK5 resides in the cytosol, forming a complex with Hsp90-Cdc37 superchaperone. In a canonical mechanism, MEK5-dependent activation results in ERK5 C-terminal autophosphorylation, Hsp90 dissociation, and nuclear translocation. This mechanism integrates signals such as growth factors and stresses that activate the MEK5-ERK5 pathway. Importantly, two other mechanisms, MEK5-independent, have been recently described. These mechanisms allow nuclear shuttling of kinase-inactive forms of ERK5. Although lacking kinase activity, these forms activate transcription by interacting with transcription factors through the TAD domain. Both mechanisms also require Hsp90 dissociation previous to nuclear translocation. One mechanism involves phosphorylation of the C-terminal tail of ERK5 by kinases that are activated during mitosis, such as Cyclin-dependent kinase-1. The second mechanism involves overexpression of chaperone Cdc37, an oncogene that is overexpressed in cancers such as prostate adenocarcinoma, where it collaborates with ERK5 to promote cell proliferation. Although some ERK5 kinase inhibitors have shown antiproliferative activity it is likely that those tumors expressing kinase-inactive nuclear ERK5 will not respond to these inhibitors.

miR-143 is associated with proliferation and apoptosis involving ERK5 in HeLa cells

Inappropriate expression of microRNA (miR) is strongly associated with carcinogenesis. miR-143 was reported to be one of the most prominent miRs implicated in the genesis and progression of human cancer. However, its correlation with cell proliferation and apoptosis in cervical cancer remains to be fully elucidated. In the present study, it was demonstrated that miR-143 is able to suppress the proliferation of cervical cancer HeLa cells and induce cell apoptosis in a time- and dose-dependent manner. The present study also investigated the potential targets of miR-143, extracellular-signal-regulated kinase 5 (ERK5) and its downstream substrate oncoprotein c-Fos, both of which are involved in cell proliferation and apoptosis. Upon increasing the miR-143 level, the ERK5 and c-Fos protein expression was significantly decreased without the effect of ERK5 transcription. Therefore, miR-143 is able to suppress cell proliferation and induce apoptosis in HeLa cells, potentially through negative regulation of ERK5 at its post-transcriptional stage.

miR-1207-3p Is a Novel Prognostic Biomarker of Prostate Cancer

MicroRNAs (miRNAs) have been found to be dysregulated in prostate cancer (PCa). In this study, we investigated if miR-1207-3p is capable of distinguishing between indolent and aggressive PCa and if it contributes to explaining the disproportionate aggressiveness of PCa in men of African ancestry (moAA). A total of 404 patients with primary adenocarcinoma of the prostate were recruited between 1988 and 2003 at the Moffitt Cancer Center, Tampa, FL, USA. Patient clinicopathological features and demographic characteristics such as race were identified. RNA samples from 404 postprostatectomy prostate tumor tissue samples were analyzed by real-time quantitative reverse transcription polymerase chain reaction for the mRNA expression of miR-1207-3p. miR-1207-3p expression in PCa that resulted in overall death or PCa-specific death is significantly higher than in PCa cases that did not. The same positive correlation holds true for other clinical characteristics such as biochemical recurrence, Gleason score, clinical stage, and prostate-specific antigen level. Furthermore, miR-1207-3p expression was significantly less in moAA in comparison to Caucasian men. We also evaluated whether miR-1207-3p is associated with clinical outcomes adjusted for age at diagnosis and tumor stage in the modeling. Using competing risk regression, the PCa patients with a high miR-1207-3p expression (≥6 vs 3) had a high risk to develop PCa recurrence (hazard rate = 2.5, P < .001) adjusting for age at diagnosis and tumor stage. In conclusion, miR-1207-3p is a promising novel prognostic biomarker for PCa. Furthermore, miR-1207-3p may also be important in explaining the disproportionate aggressiveness of PCa in moAA.

Role of microRNAs in the resistance of prostate cancer to docetaxel and paclitaxel

Taxanes, a group of cancer drugs that includes docetaxel and paclitaxel, have become a front-line therapy for a variety of metastatic cancers, but resistance can develop.

There are several docetaxel resistance mechanisms in prostate cancer: unfavorable tumor microenvironment, drug efflux pump, alterations in microtubule structure and/or function, and apoptotic defects (e.g. up regulation of Bcl-2 and clusterin or activation of the PTEN/PI3K/mTOR pathway or activation of the MAPK/ERK pathway).

MicroRNAs (miRNAs), small regulatory molecules, could also function as a contributor to the resistance of cancer cells to commonly used anti-cancer drugs.

Aberrant expressions of miRNAs that can act as tumor suppressors or oncogenes are closely associated with the development, invasion and metastasis of various cancers including prostate cancer. Nearly 50 miRNAs have been reported to be differentially expressed in human prostate cancer so far, but knowledge concerning the effects of miRNAs on the sensitivity to anti-cancer drugs is still limited. The author of the review focus on probable impact of miRNAs on the resistance to docetaxel and paclitaxel.

Overexpression of miR-21 increased the resistance of prostate cancer cells to docetaxel by targeting PDCD4, PTEN, RECK, and BTG2. Nevertheless, decreased expressions of tumor suppressors: miR-34a, miR-143, miR-148a and miR-200 family are involved in resistance of anti-cancer drugs by inhibition of apoptosis and activation of signaling pathways. Conclude miRNAs become very attractive target for potential therapeutic interventions.

Mitigation of arsenic-induced acquired cancer phenotype in prostate cancer stem cells by miR-143 restoration

Inorganic arsenic, an environmental contaminant and a human carcinogen is associated with prostate cancer. Emerging evidence suggests that cancer stem cells (CSCs) are the driving force of carcinogenesis. Chronic arsenic exposure malignantly transforms the human normal prostate stem/progenitor cell (SC) line, WPE-stem to arsenic-cancer SCs (As-CSCs), through unknown mechanisms. MicroRNAs (miRNAs) are small, non-coding RNAs that negatively regulate gene expression at the posttranscriptional level. In prior work, miR-143 was markedly downregulated in As-CSCs, suggesting a role in arsenic-induced malignant transformation. In the present study, we investigated whether loss of miR-143 expression is important in arsenic-induced transformation of prostate SCs. Restoration of miR-143 in As-CSCs was achieved by lentivirus-mediated miR-143 overexpression. Cells were assessed bi-weekly for up to 30weeks to examine mitigation of cancer phenotype. Secreted matrix metalloproteinase (MMP) activity was increased by arsenic-induced malignant transformation, but miR-143 restoration decreased secreted MMP-2 and MMP-9 enzyme activities compared with scramble controls. Increased cell proliferation and apoptotic resistance, two hallmarks of cancer, were decreased upon miR-143 restoration. Increased apoptosis was associated with decreased BCL2 and BCL-XL expression. miR-143 restoration dysregulated the expression of SC/CSC self-renewal genes including NOTCH-1, BMI-1, OCT4 and ABCG2. The anticancer effects of miR-143 overexpression appeared to be mediated by targeting and inhibiting LIMK1 protein, and the phosphorylation of cofilin, a LIMK1 substrate. These findings clearly show that miR-143 restoration mitigated multiple cancer characteristics in the As-CSCs, suggesting a potential role in arsenic-induced transformation of prostate SCs. Thus, miR-143 is a potential biomarker and therapeutic target for arsenic-induced prostate cancer.

Implications of miR cluster 143/145 as universal anti-oncomiRs and their dysregulation during tumorigenesis

Tumorigenesis is a multistep process, de-regulated due to the imbalance of oncogenes as well as anti-oncogenes, resulting in disruption of tissue homeostasis. In many cases the effect of oncogenes and anti-oncogenes are mediated by various other molecules such as microRNAs. microRNAs are small non-coding RNAs established to post-transcriptionally regulate more than half of the protein coding genes. miR cluster 143/145 is one such cancer-related microRNA cluster which is down-regulated in most of the cancers and is able to hinder tumorigenesis by targeting tumor-associated genes. The fact that they could sensitize drug-resistant cancer cells by targeting multidrug resistant genes makes them potent tools to target cancer cells. Their low levels precede events which lead to cancer progression and therefore could be considered also as biomarkers to stage the disease. Interestingly, evidence suggests the existence of several in vivo mechanisms by which this cluster is differentially regulated at the molecular level to keep their levels low in cancer. In this review, we summarize the roles of miR cluster 143/145 in cancer, their potential prognostic applications and also their regulation during tumorigenesis.

Screening for characteristic microRNAs between pre-invasive and invasive stages of cervical cancer

The aim of the present study was to investigate the characteristic microRNAs (miRNAs) expressed during the pre-invasive and invasive stages of cervical cancer. A gene expression profile (GSE7803) containing 21 invasive squamous cell cervical carcinoma samples, 10 normal squamous cervical epithelium samples and seven high-grade squamous intraepithelial cervical lesion samples, was obtained from the Gene Expression Omnibus. Differentially expressed genes (DEGs) were identified using significance analysis of microarray software, and a Gene Ontology (GO) enrichment analysis was conducted using the Database for Annotation, Visualization and Integrated Discovery. The miRNAs that interacted with the identified DEGs were selected, based on the TarBase v5.0 database. Regulatory networks were constructed from these selected miRNAs along with their corresponding target genes among the DEGs. The regulatory networks were visualized using Cytoscape. A total of 1,160 and 756 DEGs were identified in the pre-invasive and invasive stages of cervical cancer, respectively. The results of the GO enrichment demonstrated that the DEGs were predominantly involved in the immune response and the cell cycle, in the pre-invasive and invasive stages, respectively. Furthermore, a total of 18 and 26 characteristic miRNAs were screened in the pre-invasive and invasive stages, respectively. These miRNAs may be potential biomarkers and targets for the diagnosis and treatment of the different stages of cervical cancer.

MicroRNAs 143 and 145 may be involved in benign prostatic hyperplasia pathogenesis through regulation of target genes and proteins

OBJECTIVES

The aim of this study was to analyze the roles of miR-143 and miR-145, as well as the gene and protein expression of their targets (KRAS, ERK5, MAP3K3, and MAP4K4) in the pathogenesis of benign prostatic hyperplasia (BPH).

METHODS

We analyzed the specimens of 44 patients diagnosed with BPH who underwent surgical treatment. The control group consisted of prostate samples from 2 young patients who were organ donors. miRNAs and their target genes were assessed using real-time polymerase chain reaction (qRT-PCR), and protein levels were assessed by Western blotting.

RESULTS

miR-143 and miR-145 were overexpressed in, respectively, 62.5% and 73.8% of the cases. The ERK5 and MAP4K4 genes were underexpressed respectively in 59.4% and 100% of the BPH samples, whereas KRAS and MAP3K3 were overexpressed respectively in 79.4% and 61.5% of the samples. Increased protein expression was found for both KRAS (4,312.2 luminance/area) and MAP3K3 (7,461.7 luminance/area), while the ERK5 protein was more abundant in the samples from patients with prostate larger than 60 grams (p=0.019).

CONCLUSIONS

The overexpression of miR-143 and miR-145 in BPH samples suggests an association with the pathogenesis of the disease; additionally, the latter miRNA may act through the inhibition of MAP4K4. KRAS and MAP3K3 overexpression may also be associated with BPH pathogenesis. Further analyses are necessary to confirm these results.

microRNA and non-canonical TGF-β signalling: implications for prostate cancer therapy

The incidence of prostate cancer is increasing worldwide and marks a significant health issue. Paired with this, current therapeutic options for advanced prostate cancer, notably androgen deprivation therapy (ADT), fail to provide a consistent level of efficacy throughout the treatment period, highlighting the need for new robust therapies. Growth factors, such as Transforming Growth Factor-beta (TGF-β), possess the ability to impede cancer development in the early stages, via alterations in either apoptosis, cell proliferation, or the promotion of cellular senescence. However, later in the pathogenesis, advanced prostate cancer cells become insensitive to the previously beneficial effects of TGF-β. The molecular mechanisms behind this acquired insensitivity are not well understood. Thus, the aim of this review is to examine the effects of a class of small non-coding RNA, microRNA (miRNA), on TGF-β signalling. The impact of miRNA on the canonical TGF-β Smad signalling pathway has been well investigated, hence, in this review, we will examine whether miRNA targeting members of non-canonical TGF-β signalling members, such as, Erk, RhoA, PI3K/Akt and JNK/p38 could provide alternate therapeutic options for advanced prostate cancer.

Diagnostic potential of miR-126, miR-143, miR-145, and miR-652 in malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is difficult to distinguish from reactive mesothelial proliferations (RMPs). It is uncertain whether miRNAs are useful biomarkers for differentiating MPM from RMPs. Thus, we screened with a quantitative RT-PCR (RT-qPCR)-based platform the expression of 742 miRNAs in formalin-fixed, paraffin-embedded, preoperative diagnostic biopsy samples, surgically resected MPM specimens previously treated with chemotherapy, and corresponding non-neoplastic pleura (NNP), from five patients. miR-126, miR-143, miR-145, and miR-652 were significantly down-regulated (≥twofold) in resected MPM and/or chemotherapy-naïve diagnostic tumor biopsy samples. The miRNA expression pattern was validated by RT-qPCR in a cohort of 40 independent MPMs. By performing binary logistic regression on the RT-qPCR data for the four miRNAs, the established four-miRNA classifier differentiated MPM from NNP with high sensitivity and specificity (area under the curve, 0.96; 95% CI, 0.92-1.00). The classifier's optimal logit(P) value of 0.62 separated NNP and MPM samples with a sensitivity of 0.95 (95% CI, 0.89-1.00), a specificity of 0.93 (95% CI, 0.87-0.99), and an overall accuracy of 0.94 (95% CI, 0.88-1.00). The level of miR-126 in MPM was inversely correlated with that of the known target, the large neutral amino acid transporter, small subunit 1 (r = -0.38; 95% CI, -0.63 to -0.06). Overall, these results indicate that these four miRNAs may be suitable biomarkers for distinguishing MPM from RMPs.

MicroRNA-143 inhibits migration and invasion of human non-small-cell lung cancer and its relative mechanism

Background: MicroRNAs (miRNAs) play important roles in many biological processes, including cancer development. Among those miRNAs, miR-143 shows tumor-suppressive activity in some human cancers. However, the function and mechanism of miR-143 in lung cancer cells remains unknown. Here we explored the role of miR-143 in lung cancer. Results: According to qRT-PCR, we found that miR-143 was notably down-regulated in 19 NSCLC tissues and 5 cell lines. In vitro experiments showed us that miR-143 could significantly suppress the migration and invasion of NSCLC cell lines while it had no effects on the growth of NSCLC cell lines, and in vivo metastasis assay showed the same results. Finally, we found that the mechanism of miR-143 inhibiting the migration and invasion of NSCLC might be through targeting CD44v3. Conclusions: The up-regulated miR-143 in lung cancer could significantly inhibit cell migration and invasion, and this might work through targeting CD44v3, which was newly identified by us.