miR-204 mediated loss of Myeloid cell leukemia-1 results in pancreatic cancer cell death

Mcl-1 downregulation enhances BCG treatment efficacy in bladder cancer by promoting macrophage polarization

BACKGROUND

Bacillus Calmette-Guérin (BCG) is the primary method of postoperative perfusion treatment for bladder cancer. The myeloid cell leukemia gene-1 (Mcl-1) is closely associated with the development of malignant tumors. Previous research by our group has demonstrated that downregulating Mcl-1 using shRNA can enhance the efficacy of BCG treatment in bladder cancer. This study aims to investigate the impact of Mcl-1 downregulation in combination with BCG treatment on bladder cancer, macrophage polarization, and the underlying mechanism of action, with the goal of reducing recurrence and metastasis in bladder cancer.

METHODS

The GSE190529 dataset was analyzed to identify differential genes for enrichment analysis. The WGCNA algorithm was then employed to pinpoint gene modules closely associated with the Mcl-1 gene. The overlapping genes between these modules and the differentially expressed genes were subjected to enrichment analysis in GO and KEGG pathways to unveil crucial signaling pathways. In vitro experiments involved the co-culture of Raw264.7 macrophages and MB49 to establish a tumor microenvironment model, while in vivo experiments utilized an MNU-induced rat bladder cancer model. Various methods including Enzyme-Linked Immunosorbent Assay (ELISA), Western blot, immunofluorescence, HE staining, etc. were utilized to assess macrophage polarization and the expression of proteins linked to the ASK1/MKK7/JNK/cJUN signaling pathway.

RESULTS

Bioinformatics analysis indicates that the therapeutic mechanism of Mcl-1 in BCG treatment for bladder cancer may be linked to the Mitogen-Activated Protein Kinase (MAPK) signaling pathway. Both in vivo and in vitro experiments have demonstrated that the combination of BCG treatment and Mcl-1shRNA intervention results in elevated expression of M1 markers (TNF-α, CD86, INOS) and reduced expression of M2 markers (IL-10, CD206, Arg-1). Moreover, there was a notable increase in protein levels of P-ASK1, P-MKK7, P-JNK, P-cJUN, and CX43, leading to a significant rise in the apoptosis rate of bladder cancer cells and diminished proliferation, migration, and invasion capabilities. The expression of these markers can be reversed by employing the JNK signaling pathway inhibitor SP600125.

CONCLUSION

Down-regulation of Mcl-1 promotes the polarization of macrophages towards the M1 type through activation of the ASK1/MKK7/JNK signaling pathway. This enhances intercellular communication and improves the efficacy of BCG in bladder cancer treatment.

Natural products as inhibitors against pancreatic cancer cell proliferation and invasion: possible mechanisms

Pancreatic cancer is one of the gastrointestinal tumors with the lowest survival rate and the worst prognosis. At the time of diagnosis, the majority of patients have missed the opportunity for radical surgical resection and opt for chemotherapy as their primary treatment choice. And drug resistance emerges during the application of the most widely used chemotherapeutic regimens such as modified FOLFIRINOX regimen, gemcitabine monotherapy or 5-Fluorouracil combination therapy, which further reduces the therapeutic efficacy. Therefore, it is urgent to explore better treatment strategies for pancreatic cancer. In recent years, more and more studies have found that natural products have significant anti-pancreatic cancer properties. In this paper, we reviewed the possible mechanisms by which natural products inhibit the proliferation and invasion of pancreatic cancer cells, including the possible mechanisms of targeting the inhibition of the growth and proliferation regulatory pathways of pancreatic cancer cells, inducing apoptosis and autophagy of pancreatic cancer cells, inhibiting the EMT process of pancreatic cancer cells, and inhibiting the angiogenesis of pancreatic cancer. Meanwhile, natural products have also hindered the progress of their basic and clinical research due to the complexity of their composition and the limitation of biological extraction technology. Further exploration of the specific molecular mechanisms of natural products to inhibit the proliferation and invasion of pancreatic cancer cells, optimization of purification and preparation techniques, and enrichment of basic and clinical trials to verify their efficacy and safety may be the future direction of natural products in the field of anti-pancreatic cancer research.

Molecular detection of exosomal miRNAs of blood serum for prognosis of colorectal cancer

Colorectal cancer (CRC) is the third most common cancer affecting people. The discovery of new, non-invasive, specific, and sensitive molecular biomarkers for CRC may assist in the diagnosis and support therapeutic decision making. Exosomal miRNAs have been demonstrated in carcinogenesis and CRC development, which makes these miRNAs strong biomarkers for CRC. Deep sequencing allows a robust high-throughput informatics investigation of the types and abundance of exosomal miRNAs. Thus, exosomal miRNAs can be efficiently examined as diagnostic biomarkers for disease screening. In the present study, a number of 660 mature miRNAs were detected in patients diagnosed with CRC at different stages. Of which, 29 miRNAs were differentially expressed in CRC patients compared with healthy controls. Twenty-nine miRNAs with high abundance levels were further selected for subsequent analysis. These miRNAs were either highly up-regulated (e.g., let-7a-5p, let-7c-5p, let-7f-5p, let-7d-3p, miR-423-5p, miR-3184-5p, and miR-584) or down-regulated (e.g., miR-30a-5p, miR-99-5p, miR-150-5p, miR-26-5p and miR-204-5p). These miRNAs influence critical genes in CRC, leading to either tumor growth or suppression. Most of the reported diagnostic exosomal miRNAs were shown to be circulating in blood serum. The latter is a novel miRNA that was found in exosomal profile of blood serum. Some of the predicted target genes of highly expressed miRNAs participate in several cancer pathways, including CRC pathway. These target genes include tumor suppressor genes, oncogenes and DNA repair genes. Main focus was given to multiple critical signaling cross-talking pathways including transforming growth factor β (TGFβ) signaling pathways that are directly linked to CRC. In conclusion, we recommend further analysis in order to experimentally confirm exact relationships between selected differentially expressed miRNAs and their predicted target genes and downstream functional consequences.

Functions and targets of miRNAs in pharmacological and toxicological effects of major components of Tripterygium wilfordii Hook F

Tripterygium wilfordii Hook F (TwHF) has a long history of use as a traditional Chinese medicine and has been widely administered to treat various inflammatory and autoimmune diseases. MicroRNAs (miRNAs) are endogenous, short, non-coding RNAs that regulate gene expression post-transcriptionally. They participate in the efficacies and even toxicities of the components of TwHF, rendering miRNAs an appealing therapeutic strategy. This review summarizes the recent literature related to the roles and mechanisms of miRNAs in the pharmacological and toxicological effects of main components of TwHF, focusing on two active compounds, triptolide (TP) and celastrol (CEL). Additionally, the prospects for the "You Gu Wu Yun" theory regarding TwHF nephrotoxicity are presented.

Triptolide Inhibits Th17 Response by Upregulating microRNA-204-5p and Suppressing STAT3 Phosphorylation in Psoriasis

Background

Psoriasis is an immune and inflammation-related skin disease. Triptolide with immunosuppressive and anti-inflammatory properties has been utilized for psoriasis treatment. However, the potential immunological mechanisms of triptolide have not been fully elucidated.

Methods

Using an imiquimod (IMQ)-induced psoriatic mouse model, we detected the effects of triptolide on psoriasis-like lesions including scales, thickening, and erythema. Methyl thiazol tetrazolium (MTT) cytotoxicity assay was performed for evaluating the influence of triptolide on cell viability. Gene expression at mRNA and protein levels were examined by reverse transcription-quantitative polymerase chain reaction and Western blot analysis, respectively. The combination between microRNA-204-5p (miR-204-5p) and signal transduction and transcription activator-3 (STAT3) was confirmed by luciferase reporter assay. Enzyme-linked immunosorbent assay was conducted to examine interleukin (IL)-17 and interferon-γ (IFN-γ) levels using corresponding kits. Hematoxylin and eosin staining was used for the visualization of epidermal thickness. Flow cytometry analysis was employed for examining T helper (Th) 17 cells.

Results

Triptolide ameliorated IMQ-induced psoriatic skin lesions manifested by the decreased psoriasis area and severity indexes (PASI) scores. Triptolide inhibited Th17 cell differentiation from splenocytes. Additionally, triptolide elevated miR-204-5p expression, whereas it downregulated STAT3 expression levels both in vitro and in vivo. Moreover, miR-204-5p directly targeted STAT3 in HaCaT cells. Furthermore, triptolide repressed the expression of proinflammatory cytokines in IMQ-evoked psoriasis-like mice.

Conclusion

Triptolide inhibits STAT3 phosphorylation via upregulating miR-204-5p and thus suppressing Th17 response in psoriasis.

A worldwide bibliometric analysis of triptolide research from 1997 to 2021

OBJECTIVES

In recent years, triptolide has received much attention due to its wide range of pharmacological activities. However, no bibliometric studies have been published on triptolide. This study conducted a bibliometric study to provide scientific and insightful information for further research.

METHODS

This study performed a bibliometric study of articles published in the Web of Science database from 1997 to 2021. Based on the keywords used in relation to the title of the article containing the word triptolide, 970 publications were searched for further analysis. We used Microsoft Excel for frequency analysis, VOSviewer and CiteSpace for data visualization, and Rstudio for citation metrics and analysis.

RESULTS

After analysis, standard bibliometric indicators such as the growth of publications, prolific authors and coauthorship, country distributions, preferred journals, most influential institutions and top cited documents were presented in this study.

CONCLUSIONS

According to our findings, the number of triptolide-related publications has been increasing since 2009. China was the largest contributor to triptolide research, followed by the USA. Biomedicine & Pharmacotherapy was the leading journal related to triptolide research. The most productive authors were Zhang LY (China Pharmaceut Univ) and Jiang ZZ (China Pharmaceut Univ). China Pharmaceutical University was the most influential institution in the field of triptolide research. Our findings suggest that the effective use of triptolide in cancer therapy as well as overcoming its multiorgan toxicity to promote its widespread clinical applications are expected to be hot research topics in the future.

MicroRNA-204-5p: A pivotal tumor suppressor

MicroRNAs (miRNAs) are a class of non-coding single-stranded RNA molecules with a length of approximately 18-25 nt nucleotides that regulate gene expression post-transcriptionally. MiR-204-5p originates from the sixth intron of the transient receptor potential cation channel subfamily M member 3 (TRPM3) gene. MiR-204-5p is frequently downregulated in various cancer types and is related to the clinicopathological characteristics and prognosis of cancer patients. So far, many studies have determined that miR-204-5p functions as a tumor suppressor for its extensive and powerful capacity to inhibit tumor proliferation, metastasis, autophagy, and chemoresistance in multiple cancer types. MiR-204-5p appears to be a promising prognostic biomarker and a therapeutic target for human cancers. This review summarized the latest advances on the role of miR-204-5p in human cancers.

Apoptosis Triggering, an Important Way for Natural Products From Herbal Medicines to Treat Pancreatic Cancers

Pancreatic cancer, a poor prognosis and high morbidity and mortality cancer, is a malignant tumor occurring in pancreatic exocrine glands. Currently, surgery and gemcitabine (Gem) are commonly used to treat pancreatic cancers. However, the high recurrence rate and resistance makes the therapeutic effects still unsatisfied. Apoptosis is comprehensively recognized as one of the major ways of the programmed cell death, refers to the autonomous and orderly death process of cells in order to maintain the stability of the body's environment after receiving a certain signal or stimulation. Currently, it has also been proven to be a promising way for the treatment of pancreatic cancer. Nowadays, some active ingredients from herbal medicine have been reported to be effective for the treatment of pancreatic cancer via inducing cells apoptosis. Therefore, this article reviews the current references regarding anti pancreatic cancer effects of natural products derived from herbal medicines via triggering apoptosis, and summarizes the related potential signal pathways, including death receptors mediated apoptotic pathway, mitochondrial dependent apoptotic pathway, NF-κB mediated apoptotic pathways, MAPK mediated apoptotic pathway, ERS mediated apoptotic pathway, PI3K-Akt mediated apoptotic pathway, and other pathways such as JAK-STAT signal pathway, which can lay a certain foundation for the research and development of new natural products against pancreatic cancer.

miRNA-204-5p acts as tumor suppressor to influence the invasion and migration of astrocytoma by targeting ezrin and is downregulated by DNA methylation

microRNAs (miRNAs), through their regulation of the expression and activity of numerous proteins, are involved in almost all cellular processes. As a consequence, dysregulation of miRNA expression is closely associated with the development and progression of cancers. Recently, DNA methylation has been shown to play a key role in miRNA expression dysregulation in tumors. miRNA-204-5p commonly acts in the suppression of oncogenes in tumors. In this study, the levels of miRNA-204-5p were found to be down-regulated in the astrocytoma samples. miRNA-204-5p expression was also down-regulated in two astrocytoma cell lines (U87MG and LN382). Examination of online databases showed that the miRNA-204-5p promoter regions exist in CpG islands, which might be subjected to differential methylation. Subsequently, we showed that the miRNA-204-5p promoter region was hypermethylated in the astrocytoma tissue samples and cell lines. Then we found that ezrin expression was down-regulated with an increase in miRNA-204-5p expression in LN382 and U87MG cells after 5-aza-2'-deoxycytidine (5'AZA) treatment compared with control DMSO treatment. In addition, LN382 and U87MG cells treated with 5'AZA exhibited significantly inhibited cell invasion and migration . In a recovery experiment, cell invasion and migration returned to normal levels as miRNA-204-5p and ezrin levels were restored. Overall, our study suggests that miRNA-204-5p acts as a tumor suppressor to influence astrocytoma invasion and migration by targeting ezrin and that miRNA-204-5p expression is downregulated by DNA methylation. This study provides a new potential strategy for astrocytoma treatment.

MicroRNAs as biomarkers and perspectives in the therapy of pancreatic cancer

Pancreatic cancer is considered as one of the most aggressive tumor types, representing over 45,750 mortality cases annually in the USA solely. The aggressive nature and late identification of pancreatic cancer, combined with the restrictions of existing chemotherapeutics, present the mandatory need for the advancement of novel treatment systems. Ongoing reports have shown an important role of microRNAs (miRNAs) in the initiation, migration, and metastasis of malignancies. Besides, abnormal transcriptional levels of miRNAs have regularly been related with etiopathogenesis of pancreatic malignancy, underlining the conceivable utilization of miRNAs in the management of pancreatic disease patients. In this review article, we give a concise outline of molecular pathways involved in etiopathogenesis of pancreatic cancer patients as well as miRNA implications in pancreatic cancer patients. Ensuing sections describe the involvement of miRNAs in the diagnosis, prognosis, and therapy of pancreatic cancer patients. The involvement of miRNAs in the chemoresistance of pancreatic cancers was also discussed. End area portrays the substance of survey with future headings.

Myeloid cell leukemia 1 (MCL-1): Structural characteristics and application in cancer therapy

Apoptosis, a major hallmark of cancer cells, regulates cellular fate and homeostasis. BCL-2 (B-cell CLL/Lymphoma 2) protein family is popularly known to mediate the intrinsic mode of apoptosis, of which MCL-1 is a crucial member. Myeloid cell leukemia 1 (MCL-1) is an anti-apoptotic oncoprotein and one of the most investigated members of the BCL-2 family. It is commonly known to be genetically altered, aberrantly overexpressed, and primarily associated with drug resistance in various human cancers. Recent advancements in the development of selective MCL-1 inhibitors and evaluating their effectiveness in cancer treatment establish its popularity as a molecular target. The overall aim is the selective induction of apoptosis in cancer cells by using a single or combination of BCL-2 family inhibitors. Delineating the precise molecular mechanisms associated with MCL-1-mediated cancer progression will certainly improve the efficacy of clinical interventions aimed at MCL-1 and hence patient survival. This review is structured to highlight the structural characteristics of MCL-1, its specific interactions with NOXA, MCL-1-regulatory microRNAs, and at the same time focus on the emerging therapeutic strategies targeting our protein of interest (MCL-1), alone or in combination with other treatments.

Non-coding RNAs in pancreatic ductal adenocarcinoma: New approaches for better diagnosis and therapy

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive malignancies with a 5-year survival rate less than 8%, which has remained unchanged over the last 50 years. Early detection is particularly difficult due to the lack of disease-specific symptoms and a reliable biomarker. Multimodality treatment including chemotherapy, radiotherapy (used sparingly) and surgery has become the standard of care for patients with PDAC. Carbohydrate antigen 19-9 (CA 19-9) is the most common diagnostic biomarker; however, it is not specific enough especially for asymptomatic patients. Non-coding RNAs are often deregulated in human malignancies and shown to be involved in cancer-related mechanisms such as cell growth, differentiation, and cell death. Several micro, long non-coding and circular RNAs have been reported to date which are involved in PDAC. Aim of this review is to discuss the roles and functions of non-coding RNAs in diagnosis and treatments of PDAC.

Gene Expression and Transcriptome Profiling of Changes in a Cancer Cell Line Post-Exposure to Cadmium Telluride Quantum Dots: Possible Implications in Oncogenesis

Cadmium telluride quantum dots (CdTe-QDs) are acquiring great interest in terms of their applications in biomedical sciences. Despite earlier sporadic studies on possible oncogenic roles and anticancer properties of CdTe-QDs, there is limited information regarding the oncogenic potential of CdTe-QDs in cancer progression. Here, we investigated the oncogenic effects of CdTe-QDs on the gene expression profiles of Chang cancer cells. Chang cancer cells were treated with 2 different doses of CdTe-QDs (10 and 25 μg/ml) at different time intervals (6, 12, and 24 h). Functional annotations helped identify the gene expression profile in terms of its biological process, canonical pathways, and gene interaction networks activated. It was found that the gene expression profiles varied in a time and dose-dependent manner. Validation of transcriptional changes of several genes through quantitative PCR showed that several genes upregulated by CdTe-QD exposure were somewhat linked with oncogenesis. CdTe-QD-triggered functional pathways that appear to associate with gene expression, cell proliferation, migration, adhesion, cell-cycle progression, signal transduction, and metabolism. Overall, CdTe-QD exposure led to changes in the gene expression profiles of the Chang cancer cells, highlighting that this nanoparticle can further drive oncogenesis and cancer progression, a finding that indicates the merit of immediate in vivo investigation.

MicroRNAs as crucial mediators in the pharmacological activities of triptolide (Review)

Triptolide is the main bioactive constituent isolated from the Chinese herb Tripterygium wilfordii Hook F., which possesses a variety of pharmacological properties. MicroRNAs (miRNAs/miRs) are short non-coding RNAs that regulate gene expression post-transcriptionally. miRNAs are implicated in several intracellular processes, whereby their dysregulation contributes to pathogenesis of various diseases. Thus, miRNAs have great potential as biomarkers and therapeutic targets for diseases, and are implicated in drug treatment. Previous studies have reported that specific miRNAs are targeted, and their expression levels can be altered following exposure to triptolide. Thus, miRNAs are emerging as crucial mediators in the pharmacological activities of triptolide. The present review summarizes current literature on miRNAs as target molecules in the pharmacological activities of triptolide, including antitumor, anti-inflammatory, immunosuppressive, renal protective, cardioprotective, antiangiogenesis activities and multiorgan toxicity effects. In addition, the diverse signaling pathways involved are discussed to provide a comprehensive understanding of the underlying molecular mechanisms of triptolide in the regulation of target miRNAs.

Humanized anti-DEspR IgG4S228P antibody increases overall survival in a pancreatic cancer stem cell-xenograft peritoneal carcinomatosis ratnu/nu model

BACKGROUND

Pancreatic peritoneal carcinomatosis (PPC), with the worst median overall-survival (mOS), epitomizes the incurability of metastatic cancer. Cancer stem cells (CSCs) underpin this incurability. However, inhibitors of CSC-stemness fail to increase mOS in cancer patients despite preclinical tumor-reduction. This shortfall reinforces that preclinical efficacy should be defined by increased mOS in the presence of cancer comorbidities, CSC-heterogeneity and plasticity. The primary objectives of this study are: to test the dual endothelin-1/signal peptide receptor, DEspR, as a nodal therapeutic target in PPC, given DEspR induction in anoikis-resistant pancreatic CSCs, and to validate humanized anti-DEspR antibody, hu-6g8, as a potential therapeutic for PPC.

METHODS

We used heterogeneous pools of CSCs selected for anoikis resistance from reprogrammed Panc1 and MiaPaCa2 tumor cells (TCs), and adherent TCs reprogrammed from CSCs (cscTCs). We used multiple anti-DEspR blocking antibodies (mAbs) with different epitopes, and a humanized anti-DEspR recombinant mAb cross-reactive in rodents and humans, to test DEspR inhibition effects. We measured DEspR-inhibition efficacy on multiple prometastatic CSC-functions in vitro, and on tumorigenesis and overall survival in a CSC-derived xenograft (CDX) nude rat model of PPC with comorbidities.

RESULTS

Here we show that DEspR, a stress-survival receptor, is present on subsets of PDAC Panc1-TCs, TC-derived CSCs, and CSC-differentiated TCs (cscTCs), and that DESpR-inhibition decreases apoptosis-resistance and pro-metastatic mesenchymal functions of CSCs and cscTCs in vitro. We resolve the DNA-sequence/protein-function discordance by confirming ADAR1-RNA editing-dependent DEspR-protein expression in Panc1 and MiaPaCa2 TCs. To advance DEspR-inhibition as a nodal therapeutic approach for PPC, we developed and show improved functionality of a recombinant, humanized anti-DEspR IgG4S228P antibody, hu-6g8, over murine precursor anti-DEspR mabs. Hu-6g8 internalizes and translocates to the nucleus colocalized with cyto-nuclear shuttling galectins-1/3, and induces apoptotic cell changes. DEspR-inhibition blocks transperitoneal dissemination and progression to peritoneal carcinomatosis of heterogeneous DEspR±/CD133 ± Panc1-derived CSCs in xenografted nude rats, improving mOS without chemotherapy-like adverse effects. Lastly, we show DEspR expression in Stage II-IV primary and invasive TCs in the stroma in PDAC-patient tumor arrays.

CONCLUSION

Collectively, the data support humanized anti-DEspR hu-6g8 as a potential targeted antibody-therapeutic with promising efficacy, safety and prevalence profiles for PPC patients.

The Anti-apoptotic Role of 3'-Untranslational Region in Response to Angiotensin II via Mcl1 Expression

Myeloid cell leukemia 1 (Mcl1), an abundant protein in the myocardium, plays an essential role in fibrosis and anti-inflammation in cardiomyocytes to prevent heart failure. However, whether Mcl1 3′-untranslated regions (3′-UTR) has the cardio-protecting function remains unclear. Down-regulation of Mcl1 was observed in adult mice heart tissues after Angiotensin II (Ang II) treatment. Consistent with in vivo results, the reduction of Mcl1 expression was identified in Ang II-treated neonatal cardiomyocytes. Mechanistically, Mcl1 3′-UTR prevented Ang II-induced cardiac apoptosis via up-regulation of Mcl1 and an angiogenic factor with a G-patch domain and a forkhead-associated domain 1 (Aggf1), which plays cardiac-protective role. Our work broadens the scope of gene therapy targets and provides a new insight into gene therapy strategies involving mRNAs’ 3′-UTRs application.

Role of TGF-β/Smad Pathway in the Transcription of Pancreas-Specific Genes During Beta Cell Differentiation

Autoimmune destruction of pancreatic beta cells causes absolute insulin deficiency and results in type 1 diabetes mellitus (T1DM). The substitution of healthy pancreatic beta cells for damaged cells would be the ideal treatment for T1DM; thus, the generation of pancreatic beta cells from adult stem cells represents an attractive avenue for research. In this study, a cocktail of factors was used to induce the differentiation of pancreatic beta cells from mesenchymal stem cells (MSCs). The differentiation program was divided into five stages, and the roles of the cocktail factors used during each stage were systematically elucidated. Activin A was found to phosphorylate Smad2 and Smad3 in stage III, thereby activating the TGF-β/Smad pathway. Meanwhile, the endocrine-specific transcription factor, Ngn3, and the pancreas-specific miRNAs, miR-375 and miR-26a, were dramatically elevated in stage III. We next demonstrated that Smad4, an important transcription factor in the TGF-β/Smad pathway, could bind to the promoter sequences of target genes and enhance their transcription to initiate the differentiation of beta cells. Use of SB-431542, an inhibitor of the TGF-β/Smad pathway, demonstrated in vivo and in vitro that this pathway plays a critical role in the production of pancreatic beta cells and in modulating insulin secretion. Thus, the TGF-β/Smad pathway is involved in the production of beta cells from adult stem cells by enhancing the transcription of Ngn3, miR-375, and miR-26a. These findings further underline the significant promise of cell transplant therapies for type 1 diabetes mellitus.

CDK5 Inhibitor Downregulates Mcl-1 and Sensitizes Pancreatic Cancer Cell Lines to Navitoclax

Developing small molecules that indirectly regulate Mcl-1 function has attracted a lot of attention in recent years. Here, we report the discovery of an aminopyrazole, 2-([1,1'-biphenyl]-4-yl)-N-(5-cyclobutyl-1H-pyrazol-3-yl)acetamide (analog 24), which selectively inhibited cyclin-dependent kinase (CDK) 5 over CDK2 in cancer cell lines. We also show that analog 24 reduced Mcl-1 levels in a concentration-dependent manner in cancer cell lines. Using a panel of doxycycline inducible cell lines, we show that CDK5 inhibitor 24 selectively modulates Mcl-1 function while the CDK4/6 inhibitor 6-acetyl-8-cyclopentyl-5-methyl-2-(5-(piperazin-1-yl)pyridin-2-ylamino)pyrido[2,3-day]pyrimidin-7(8H)-one does not. Previous studies using RNA interference and CRISPR showed that concurrent elimination of Bcl-xL and Mcl-1 resulted in induction of apoptosis. In pancreatic cancer cell lines, we show that either CDK5 knockdown or expression of a dominant negative CDK5 results in synergistic induction of apoptosis. Moreover, concurrent pharmacological perturbation of Mcl-1 and Bcl-xL in pancreatic cancer cell lines using a CDK5 inhibitor analog 24 that reduced Mcl-1 levels and 4-(4-{[2-(4-chlorophenyl)-5,5-dimethyl-1-cyclohexen-1-yl]methyl}-1-piperazinyl)-N-[(4-{[(2R)-4-(4-morpholinyl)-1-(phenylsulfanyl)-2-butanyl]amino}-3-[(trifluoromethyl)sulfonyl]phenyl)sulfonyl] benzamide (navitoclax), a Bcl-2/Bcl-xL/Bcl-w inhibitor, resulted in synergistic inhibition of cell growth and induction of apoptosis. In conclusion, we demonstrate targeting CDK5 will sensitize pancreatic cancers to Bcl-2 protein inhibitors. SIGNIFICANCE STATEMENT: Mcl-1 is stabilized by CDK5-mediated phosphorylation in pancreatic ductal adenocarcinoma, resulting in the deregulation of the apoptotic pathway. Thus, genetic or pharmacological targeting of CDK5 sensitizes pancreatic cancers to Bcl-2 inhibitors, such as navitoclax.

Gene Regulation by Antitumor miR-204-5p in Pancreatic Ductal Adenocarcinoma: The Clinical Significance of Direct RACGAP1 Regulation

Previously, we established a microRNA (miRNA) expression signature in pancreatic ductal adenocarcinoma (PDAC) tissues using RNA sequencing and found significantly reduced expression of miR-204-5p. Here, we aimed to investigate the functional significance of miR-204-5p and to identify miR-204-5p target genes involved in PDAC pathogenesis. Cancer cell migration and invasion were significantly inhibited by ectopic expression of miR-204-5p in PDAC cells. Comprehensive gene expression analyses and in silico database searches revealed 25 putative targets regulated by miR-204-5p in PDAC cells. Among these target genes, high expression levels of RACGAP1, DHRS9, AP1S3, FOXC1, PRP11, RHBDL2 and MUC4 were significant predictors of a poor prognosis of patients with PDAC. In this study, we focused on RACGAP1 (Rac guanosine triphosphatase-activating protein 1) because its expression was most significantly predictive of PDAC pathogenesis (overall survival rate: p = 0.0000548; disease-free survival rate: p = 0.0014). Overexpression of RACGAP1 was detected in PDAC clinical specimens, and its expression enhanced the migration and invasion of PDAC cells. Moreover, downstream genes affected by RACGAP1 (e.g., MMP28, CEP55, CDK1, ANLN and S100A14) are involved in PDAC pathogenesis. Our strategy to identify antitumor miRNAs and their target genes will help elucidate the molecular pathogenesis of PDAC.

MicroRNA-204 attenuates the migration and invasion of pancreatic cancer cells by targeting ZEB1/EMT axis

Pancreatic cancer (PC) is one of the most aggressive malignancies worldwide. MicroRNAs play an important role in the development and progression of PC, but little is known about the role of miR-204 in PC. In this study, we revealed that miR-204 was downregulated in PC tissues and cell lines, and its expression was closely correlated with aggressive clinicopathological features of PC patients. Both gain- and loss-of-function studies showed that miR-204 overexpression inhibits the proliferation, migration and invasion of PC cells, whereas miR-204 knockdown had the opposite effects. Using mouse models, we found that miR-204 overexpression suppressed PC tumor growth in vivo. Moreover, miR-204 overexpression notably suppressed epithelial-mesenchymal transition (EMT) of PC cells, and through bioinformatics analysis and dual-luciferase reporter assay, ZEB1, a critical EMT promoter, was identified to be the functional target of miR-204 in PC cells. Rescue experiments further showed that ZEB1 overexpression abrogated the effects of miR-204 in PC cells. Collectively, these findings demonstrated the tumor suppressive role of miR-204 in PC through the ZEB1/EMT axis, therefore providing a novel therapeutic target for human PC.

IL-6R/STAT3/miR-204 feedback loop contributes to cisplatin resistance of epithelial ovarian cancer cells

Enhanced chemoresistance is, among other factors, believed to be responsible for treatment failure and tumor relapse in patients with epithelial ovarian cancer (EOC). Here, we exposed EOC cells to interleukin-6 (IL-6) to activate oncogenic STAT3, which directly repressed miR-204 via a conserved STAT3-binding site near the TRPM3 promoter region upstream of miR-204. Repression of miR-204 was required for IL-6-induced cisplatin (cDDP) resistance. Furthermore, we identified the IL-6 receptor (IL-6R), which mediates IL-6-dependent STAT3 activation, as a direct miR-204 target. Importantly, the resulting IL-6R/STAT3/miR-204 feedback loop was identified in patients with EOC, and its activity correlated with chemosensitivity. Moreover, exogenous miR-204 blocked this circuit and enhanced cDDP sensitivity both in vitro and in vivo by inactivating IL-6R/STAT3 signaling and subsequently decreasing the expression of anti-apoptotic proteins. Our findings illustrate the function of this feedback loop in cDDP-based therapy and may offer a broadly useful approach to improve EOC therapy.

Cooperative multi-targeting of signaling networks by angiomiR-204 inhibits vasculogenic mimicry in breast cancer cells

RNA-based multi-target therapies focused in the blocking of signaling pathways represent an attractive approach in cancer. Here, we uncovered a miR-204 cooperative targeting of multiple signaling transducers involved in vasculogenic mimicry (VM). Our data showed that invasive triple negative MDA-MB-231 and Hs-578T breast cancer cells, but not poorly invasive MCF-7 cells, efficiently undergoes matrix-associated VM under hypoxia. Ectopic restoration of miR-204 in MDA-MB-231 cells leads to a potent inhibition of VM and reduction of number of branch points and patterned 3D channels. Further analysis of activation state of multiple signaling pathways using Phosphorylation Antibody Arrays revealed that miR-204 reduced the expression and phosphorylation levels of 13 proteins involved in PI3K/AKT, RAF1/MAPK, VEGF, and FAK/SRC signaling. In agreement with phospho-proteomic profiling, VM was impaired following pharmacological administration of PI3K and SRC inhibitors. Mechanistic studies confirmed that miR-204 exerts a negative post-transcriptional regulation of PI3K-α and c-SRC proto-oncogenes. Moreover, overall survival analysis of a large cohort of breast cancer patients indicates that low miR-204 and high FAK/SRC levels were associated with worst outcomes. In conclusion, our study provides novel lines of evidence indicating that miR-204 may exerts a fine-tuning regulation of the synergistic transduction of PI3K/AKT/FAK mediators critical in VM formation.

Impact of RUNX2 on drug-resistant human pancreatic cancer cells with p53 mutations

Background

Despite the remarkable advances in the early diagnosis and treatment, overall 5-year survival rate of patients with pancreatic cancer is less than 10%. Gemcitabine (GEM), a cytidine nucleoside analogue and ribonucleotide reductase inhibitor, is a primary option for patients with advanced pancreatic cancer; however, its clinical efficacy is extremely limited. This unfavorable clinical outcome of pancreatic cancer patients is at least in part attributable to their poor response to anti-cancer drugs such as GEM. Thus, it is urgent to understand the precise molecular basis behind the drug-resistant property of pancreatic cancer and also to develop a novel strategy to overcome this deadly disease.

Review

Accumulating evidence strongly suggests that p53 mutations contribute to the acquisition and/or maintenance of drug-resistant property of pancreatic cancer. Indeed, certain p53 mutants render pancreatic cancer cells much more resistant to GEM, implying that p53 mutation is one of the critical determinants of GEM sensitivity. Intriguingly, runt-related transcription factor 2 (RUNX2) is expressed at higher level in numerous human cancers such as pancreatic cancer and osteosarcoma, indicating that, in addition to its pro-osteogenic role, RUNX2 has a pro-oncogenic potential. Moreover, a growing body of evidence implies that a variety of miRNAs suppress malignant phenotypes of pancreatic cancer cells including drug resistance through the down-regulation of RUNX2. Recently, we have found for the first time that forced depletion of RUNX2 significantly increases GEM sensitivity of p53-null as well as p53-mutated pancreatic cancer cells through the stimulation of p53 family TAp63/TAp73-dependent cell death pathway.

Conclusions

Together, it is likely that RUNX2 is one of the promising molecular targets for the treatment of the patients with pancreatic cancer regardless of their p53 status. In this review article, we will discuss how to overcome the serious drug-resistant phenotype of pancreatic cancer.

8-Chrysoeriol, as a potential BCL-2 inhibitor triggers apoptosis of SW1990 pancreatic cancer cells

8-Chrysoeriol, a bioactive flavanoid, was firstly identified to bind directly to BCL-2 as BH3 mimetics by structure-based virtual ligand screening. And 3D docking model revealed the molecular basis of 8-Chrysoeriol targeting to BCL-2. The interaction between 8-Chrysoeriol and BCL-2 was further confirmed using Microscale Thermophoresis (MST) technique. Meanwhile, high expression level of antiapoptotic protein BCL-2 was detected in SW1990 pancreatic cancer cells and 8-Chrysoeriol showed obvious proapoptosis effect against SW1990 in vitro. Collectively, the results showed that 8-Chrysoeriol as a natural dietary product potentially targeting to BCL-2 could serve as a lead compound for SW1990 pancreatic cancer therapy.

Genetic variation of the gene coding for microRNA-204 (miR-204) is a risk factor in acute myeloid leukaemia

BACKGROUND

MicroRNAs (miRNAs or miRs) are small molecules known to be involved in post-transcriptional gene expression. Many of them have been shown to influence risk for various diseases. Recent studies suggest that lower expression of miR-204, a gene coding for miRNA-204, is correlated with shorter survival in patients with acute myeloid leukaemia (AML). This observation prompted us to analyse the effect of two polymorphisms of the miR-204 gene, one in the upstream flanking region (rs718447 A > G) and the other inside the gene itself (rs112062096 A > G), both also in intron 3 of the TRPM3 gene.

METHODS

The study was conducted on DNA samples isolated from AML patients (n = 95) and healthy individuals (n = 148), who were genotyped using the Light SNiP assays.

RESULTS

The miR-204 rs718447 GG homozygosity was found to constitute a risk factor associated with susceptibility to AML (73/95 vs 92/148, AML patients vs healthy controls, OR = 2.020, p = 0.017). Additionally, this genotype was more frequent in patients with subtypes M0-M1 in the French-American-British (FAB) classification as compared to patients with subtypes M2-M7 (23/25 vs 39/57, p = 0.026). We also found that presence of allele A was linked to longer survival of AML patients.

CONCLUSIONS

Our results show that polymorphism in miR-204 flanking region may constitute a risk and prognostic factor in AML.

The dietary compound luteolin inhibits pancreatic cancer growth by targeting BCL-2

Luteolin, a bioactive flavonoid from celery (Apium graveolens), has been rationally proved to trigger SW1990 cells to apoptosis by targeting BCL-2, and may serve as a potential agent for this cancer therapy.

Reduced FBXW7 expression in pancreatic cancer correlates with poor prognosis and chemotherapeutic resistance via accumulation of MCL1

Pancreatic cancer is a highly malignant tumor type with poor outcomes, and elucidation of the mechanisms involved in cancer progression and therapeutic resistance is critical. FBXW7 is a key regulator of tumor malignant potential, and its substrate MCL1 regulates therapeutic resistance in human malignancies. Therefore, determination of the relevance of FBXW7 expression is critical for improving patient outcomes. In this study, we investigated the function and clinical significance of FBXW7 in pancreatic cancer. FBXW7 expression was evaluated by immunohistochemistry in 122 pancreatic cancer tissues. Reduced FBXW7 expression was significantly associated with advanced venous invasion, high MCL1 expression, enhanced Ki-67 expression, and poor prognosis and was an independent poor prognostic factor. Among patients who underwent gemcitabine treatment after surgery, reduced FBXW7 expression was also significantly associated with poor prognosis. Knockdown of FBXW7 in vitro enhanced cell proliferation, and migration, and invasion abilities and promoted gemcitabine and nab-paclitaxel chemoresistance in pancreatic cancer cells. Moreover, FBXW7-knockdown cells showed accumulation of MCL1, and the enhanced chemoresistance observed in FBXW7-knockdown cells was eliminated by MCL1 suppression. These results suggested that FBXW7 was associated with cancer progression and mediated sensitivity to gemcitabine and nab-paclitaxel via MCL1 accumulation in pancreatic cancer. Thus, the FBXW7/MCL1 axis may be a promising therapeutic tool to overcome refractory pancreatic cancer.

Effect of the Natural Product Triptolide on Pancreatic Cancer: A Systematic Review of Preclinical Studies

Objective: Triptolide (TL), a natural product isolated from Tripterygium wilfordii Hook F (TwHF), shows potent anticancer effects in vitro and in vivo. We aimed to summary the biochemical mechanisms through which TL has been shown to induce apoptosis, autophagy and inhibit angiogenesis in pancreatic cancer (PC).

Methods: We undertook a systematic review of preclinical evidence. We searched electronic databases. The potential mechanisms and the underlying signaling pathways have been accumulated as well.

Results: We screened 116 abstracts for eligibility and included 17 preclinical studies in the analysis. Details of the animals and cell lines were provided in 16 studies (94.1%). Six studies (75.0%) randomly assigned animals to treatment or control groups and only 1 study (12.5%) reported on blinding. The majority of the TL's research field has focused on its pro-apoptotic effects through downregulation of inhibitory pathways and upregulation of apoptotic pathways. The studies have shown that TL is effective both in vitro and in vivo against PC cells.

Conclusion: This study provides a systematic summary of TL's anti-pancreatic cancer profile and the underlying mechanisms of with special emphasis on the apoptosis, autophagy, angiogenesis and related molecular pathways. Improved study quality in terms of treatment allocation methods reporting, randomization and blinding will accelerate needed progress toward trials.

The emergence of noncoding RNAs as Heracles in autophagy

Macroautophagy/autophagy is a catabolic process that is widely found in nature. Over the past few decades, mounting evidence has indicated that noncoding RNAs, ranging from small noncoding RNAs to long noncoding RNAs (lncRNAs) and even circular RNAs (circRNAs), mediate the transcriptional and post-transcriptional regulation of autophagy-related genes by participating in autophagy regulatory networks. The differential expression of noncoding RNAs affects autophagy levels at different physiological and pathological stages, including embryonic proliferation and differentiation, cellular senescence, and even diseases such as cancer. We summarize the current knowledge regarding noncoding RNA dysregulation in autophagy and investigate the molecular regulatory mechanisms underlying noncoding RNA involvement in autophagy regulatory networks. Then, we integrate public resources to predict autophagy-related noncoding RNAs across species and discuss strategies for and the challenges of identifying autophagy-related noncoding RNAs. This article will deepen our understanding of the relationship between noncoding RNAs and autophagy, and provide new insights to specifically target noncoding RNAs in autophagy-associated therapeutic strategies.

Dual targeting of ANGPT1 and TGFBR2 genes by miR-204 controls angiogenesis in breast cancer

Deregulated expression of microRNAs has been associated with angiogenesis. Studying the miRNome of locally advanced breast tumors we unsuspectedly found a dramatically repression of miR-204, a small non-coding RNA with no previous involvement in tumor angiogenesis. Downregulation of miR-204 was confirmed in an independent cohort of patients and breast cancer cell lines. Gain-of-function analysis indicates that ectopic expression of miR-204 impairs cell proliferation, anchorage-independent growth, migration, invasion, and the formation of 3D capillary networks in vitro. Likewise, in vivo vascularization and angiogenesis were suppressed by miR-204 in a nu/nu mice model. Genome-wide profiling of MDA-MB-231 cells expressing miR-204 revealed changes in the expression of hundred cancer-related genes. Of these, we focused on the study of pro-angiogenic ANGPT1 and TGFβR2. Functional analysis using luciferase reporter and rescue assays confirmed that ANGPT1 and TGFβR2 are novel effectors downstream of miR-204. Accordingly, an inverse correlation between miR-204 and ANGPT1/TGFβR2 expression was found in breast tumors. Knockdown of TGFβR2, but not ANGPT1, impairs cell proliferation and migration whereas inhibition of both genes inhibits angiogenesis. Taken altogether, our findings reveal a novel role for miR-204/ANGPT1/TGFβR2 axis in tumor angiogenesis. We propose that therapeutic manipulation of miR-204 levels may represent a promising approach in breast cancer.

MicroRNA in pancreatic adenocarcinoma: predictive/prognostic biomarkers or therapeutic targets?

Pancreatic ductal adenocarcinoma (PDAC) is a tumor with a poor prognosis, short overall survival and few chemotherapeutic choices. MicroRNAs (miRNAs) are non-coding, single-stranded RNAs of around 22 nucleotides involved in the pathogenic mechanisms of carcinogenesis and metastasis. They have been studied in many tumors in order to identify potential diagnostic, prognostic or therapeutic targets. In the current literature, many studies have analyzed the role of miRNAs in PDAC. In fact, the absence of appropriate biomarkers, the difficultly of early detection of this tumor, and the lack of effective chemotherapy in patients with unresectable disease have focused attention on miRNAs as new, interesting advance in this malignancy.

In this review we analyzed the role of miRNAs in PDAC in order to understand the mechanisms of action and the difference between the onco-miRNA and the tumor suppressor miRNA. We also reviewed all the data related to the use of these molecules as predictive as well as prognostic biomarkers in the course of the disease.

Finally, the possible therapeutic use of miRNAs or anti-miRNAs in PDAC is also discussed.

In conclusion, although there is still no clinical application for these molecules in PDAC, it is our opinion that the preclinical evidence of the role of specific miRNAs in carcinogenesis, the possibility of using miRNAs as diagnostic or prognostic biomarkers, and their potential therapeutic role, warrant future studies in PDAC.

The dual regulatory role of miR-204 in cancer

MicroRNAs (miRNAs) are a group of endogenous, small (about 22 nucleotides) non-coding RNAs which negatively regulate gene expressions. As one of them, miR-204 originates from the sixth intron of the transient receptor potential melastatin 3 (TRPM3) gene. Therefore, expression of miR-204 is under the control of the TRPM3 promoter and regulated by genetic and epigenetic mechanisms. miR-204 has been found to play the important roles in development of eyes and adipogenesis. Its pathological functions have been observed in a few diseases including pulmonary arterial hypertension, diabetes, and various types of cancers. It is believed that miR-204 acts as a tumor-suppressor via promoting apoptosis, conferring the resistance of cancer cells to chemotherapy, and suppressing the self-renewal of cancer stem cells (CSCs) and the epithelial to mesenchymal transition (EMT). Expression of miR-204 is repressed by its targets XRN1 and TRKB in prostate cancer and endometrial carcinoma, respectively; therefore, they establish an oncogenic feedback loops that play an important role promoting development of cancer. In this review, we summarize our current knowledge regarding miR-204, including its expression, regulation and biological functions, especially focusing our discussion on its role in tumor development and tumor progression.

MicroRNA-204 modulates colorectal cancer cell sensitivity in response to 5-fluorouracil-based treatment by targeting high mobility group protein A2

MicroRNAs (miRNAs) are a conserved class of ∼22 nucleotide RNAs that playing important roles in various biological processes including chemoresistance. Recently, many studies have revealed that miR-204 is significantly attenuated in colorectal cancer (CRC), suggesting that this miRNA may have a function in CRC. However, whether miR-204 modulates chemosensitivity to 5-fluorouracil (5-Fu) in colorectal cancer is still unclear. In our present study, we discuss this possibility and the potential mechanism exerting this effect. We identified high mobility group protein A2 (HMGA2) as a novel direct target of miR-204 and showed that miR-204 expression was decreased while HMGA2 expression was increased in CRC cell lines. Additionally, both MiR-204 overexpression and HMGA2 inhibition attenuated cell proliferation, whereas forced expression of HMGA2 partly restored the inhibitory effect of miR-204 on HCT116 and SW480 cells. Moreover, the miR-204/HMGA2 axis modulated the resistance of tumor cells to 5-Fu in HCT-116 and SW480 colon cancer cells via activation of the PI3K/AKT pathway. These results demonstrate that the miR-204/HMGA2 axis could play a vital role in the 5-Fu resistance of colon cancer cells. Taken together, our present study elucidated that miR-204 upregulated 5-Fu chemosensitivity via the downregulation of HMGA2 in colorectal cancer and provided significant insight into the mechanism of 5-Fu resistance in colorectal cancer patients. More importantly, our present study suggested that miR-204 has potential as a therapeutic strategy for 5-Fu-resistant colorectal cancer.

Summary: miR-204 upregulates 5-Fu chemosensitivity via the downregulation of HMGA2 in colorectal cancer and provides significant insight into the mechanism of 5-Fu resistance in colorectal cancer patients.

Genome-wide identification of target genes for miR-204 and miR-211 identifies their proliferation stimulatory role in breast cancer cells

MiR-204 and miR-211 (miR-204/211) share the same seed site sequence, targeting many of the same genes. Their role in cancer development remains controversial, as both cell proliferative and suppressive effects have been identified. This study aimed to address the relationship between the two structurally similar microRNAs (miRs) by examining their target genes in depth as well as to reveal their contribution in breast cancer cells. Genome-wide pathway analysis with the dysregulated genes after overexpression of either of the two miRs in MCF-7 breast cancer cell identified the “Cancer”- and “Cell signaling”-related pathway as the top pathway for miR-204 and miR-211, respectively. The majority of the target genes for both miRs notably comprised ones that have been characterized to drive cells anti-tumorigenic. Accordingly, the miRs induced the proliferation of MCF-7 and MDA-MB-231 cells, judged by cell proliferation as well as colony forming assay. Tumor suppressors, MX1 and TXNIP, were proven to be direct targets of the miRs. In addition, a high association was observed between miR-204 and miR-211 expression in breast cancer tissue. Our results indicate that miR-204/211 serve to increase cell proliferation at least in MCF-7 and MDA-MB-231 breast cancer cells by downregulating tumor suppressor genes.

CD5 expression is regulated during human T-cell activation by alternative polyadenylation, PTBP1, and miR-204

T lymphocytes stimulated through their antigen receptor (TCR) preferentially express mRNA isoforms with shorter 3´ untranslated regions (3´-UTRs) derived from alternative pre-mRNA cleavage and polyadenylation (APA). However, the physiological relevance of APA programs remains poorly understood. CD5 is a T-cell surface glycoprotein that negatively regulates TCR signaling from the onset of T-cell activation. CD5 plays a pivotal role in mediating outcomes of cell survival or apoptosis, and may prevent both autoimmunity and cancer. In human primary T lymphocytes and Jurkat cells we found three distinct mRNA isoforms encoding CD5, each derived from distinct poly(A) signals (PASs). Upon T-cell activation, there is an overall increase in CD5 mRNAs with a specific increase in the relative expression of the shorter isoforms. 3´-UTRs derived from these shorter isoforms confer higher reporter expression in activated T cells relative to the longer isoform. We further show that polypyrimidine tract binding protein (PTB/PTBP1) directly binds to the proximal PAS and PTB siRNA depletion causes a decrease in mRNA derived from this PAS, suggesting an effect on stability or poly(A) site selection to circumvent targeting of the longer CD5 mRNA isoform by miR-204. These mechanisms fine-tune CD5 expression levels and thus ultimately T-cell responses.

Developments in miRNA gene signaling pathways in pancreatic cancer

Pancreatic cancer is a devastating malignancy that ranks as the fourth leading cause of cancer-related deaths worldwide. Dismal prognosis is mainly attributable to limited knowledge of the molecular pathogenesis of the disease. miRNAs have been found to be deregulated in pancreatic cancer, affecting several steps of initiation and aggressiveness of the disease by regulating important signaling pathways, such as the KRAS and Notch pathways. Moreover, the effect of miRNAs on regulating cell cycle events and expression of transcription factors has gained a lot of attention. Recent studies have highlighted the application of miRNAs as biomarkers and therapeutic tools. The current review focuses on latest advances with respect to the roles of miRNAs in pancreatic ductal adenocarcinoma associated signaling pathways and miRNA-based therapeutics.

MiR-204 inhibits the proliferation and invasion of renal cell carcinoma by inhibiting RAB22A expression

While miR-204 expression may be linked to renal cell carcinoma (RCC) progression, the detailed mechanisms remain unclear. In the present study, we demonstrated that miR-204 was differentially expressed in RCC tissues when compared with surrounding normal kidney tissues. Ectopic overexpression of miR-204 in human RCC cells suppressed cell proliferation and invasion in vitro and in vivo. Mechanism dissection revealed that miR-204 may function through RAB22A signals to inhibit RCC proliferation and invasion. Overexpression of RAB22A by oe-RAB22A was able to partially reverse the miR-204-mediated suppression of RCC tumor progression. Together, these results revealed that miR-204 suppressed RCC proliferation and invasion by directly targeting the RAB22A gene. Targeting newly identified RAB22A with miR-204 may aid in the suppression of RCC proliferation and invasion.

Identification of potential biomarkers to differentially diagnose solid pseudopapillary tumors and pancreatic malignancies via a gene regulatory network

Background

Solid pseudopapillary neoplasms (SPN) are pancreatic tumors with low malignant potential and good prognosis. However, differential diagnosis between SPN and pancreatic malignancies including pancreatic neuroendocrine tumor (PanNET) and ductal adenocarcinoma (PDAC) is difficult. This study tried to identify candidate biomarkers for the distinction between SPN and the two malignant pancreatic tumors by examining the gene regulatory network of SPN.

Methods

The gene regulatory network for SPN was constructed by a co-expression model. Genes that have been reported to be correlated with SPN were used as the clues to hunt more SPN-related genes in the network according to a shortest path approach. By means of the K-nearest neighbor algorithm (KNN) classifier evaluated by the jackknife test, sets of genes to distinguish SPN and malignant pancreatic tumors were determined.

Results

We took a new strategy to identify candidate biomarkers for differentiating SPN from the two malignant pancreatic tumors PanNET and PDAC by analyzing shortest paths among SPN-related genes in the gene regulatory network. 43 new SPN-relevant genes were discovered, among which, we found hsa-miR-194 and hsa-miR-7 along with 7 transcription factors (TFs) such as SOX11, SMAD3 and SOX4 etc. could correctly differentiate SPN from PanNET, while hsa-miR-204 and 4 TFs such as SOX9, TCF7 and PPARD etc. were demonstrated as the potential markers for SPN versus PDAC. 14 genes were demonstrated to serve as the candidate biomarkers for distinguishing SPN from PanNET and PDAC when considering them as malignant pancreatic tumors together.

Conclusion

This study provides new candidate genes related to SPN and the potential biomarkers to differentiate SPN from PanNET and PDAC, which may help to diagnose patients with SPN in clinical setting. Furthermore, candidate biomarkers such as SOX11 and hsa-miR-204 which could cause cell proliferation but inhibit invasion or metastasis may be of importance in understanding the molecular mechanism of pancreatic oncogenesis and could be possible therapeutic targets for malignant pancreatic tumors.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-015-0718-3) contains supplementary material, which is available to authorized users.

Noninvasive urinary miRNA biomarkers for early detection of pancreatic adenocarcinoma

Currently, the majority of patients diagnosed with pancreatic ductal adenocarcinoma (PDAC) present with locally invasive and/or metastatic disease, resulting in five-year survival of less than 5%. The development of an early diagnostic test is, therefore, expected to significantly impact the patient's prognosis. In this study, we successfully evaluated the feasibility of identifying diagnostic cell free microRNAs (miRNAs) for early stage PDAC, through the analysis of urine samples. Using Affymetrix microarrays, we established a global miRNA profile of 13 PDAC, six chronic pancreatitis (CP), and seven healthy (H) urine specimens. Selected differentially expressed miRNAs were subsequently investigated using an independent technique (RT-PCR) on 101 urine samples including 46 PDAC, 29 CP and 26 H. Receiver operating characteristic (ROC) and logistic regression analyses were applied to determine the discriminatory potential of the candidate miRNA biomarkers. Three miRNAs (miR-143, miR-223, and miR-30e) were significantly over-expressed in patients with Stage I cancer when compared with age-matched healthy individuals (P=0.022, 0.035 and 0.04, respectively); miR-143, miR-223 and miR-204 were also shown to be expressed at higher levels in Stage I compared to Stages II-IV PDAC (P=0.025, 0.013 and 0.008, respectively). Furthermore, miR-223 and miR-204 were able to distinguish patients with early stage cancer from patients with CP (P=0.037 and 0.036). Among the three biomarkers, miR-143 was best able to differentiate Stage I (n=6) from healthy (n=26) with area under the curve (AUC) of 0.862 (95% CI 0.695-1.000), with sensitivity (SN) of 83.3% (95% CI 50.0-100.0), and specificity (SP) of 88.5% (95% CI 73.1-100.0). The combination of miR-143 with miR-30e was significantly better at discriminating between these two groups, achieving an AUC of 0.923 (95% CI 0.793-1.000), with SN of 83.3% (95% CI 50.0-100.0) and SP of 96.2% (95% CI 88.5-100.0). In this feasibility study, we demonstrate for the first time the utility of miRNA biomarkers for non-invasive, early detection of PDAC in urine specimens.

Trichostatin A and Tamoxifen inhibit breast cancer cell growth by miR-204 and ERα reducing AKT/mTOR pathway

MicroRNAs (miRs) are small non-coding RNAs aberrantly expressed in human tumors. Increasing evidence suggests that miRNAs are functionally important in cancers. We demonstrated miR-204 exerts its function by targeting gene involved in tumor growth and chemotherapy drugs reactivity. Here, we show that Trichostatin A (TSA) could increase ERα expression in MCF-7 and MDA-MB-231 cells by reducing miR204. Analysis of tumors growth inhibition shows that TSA promotes ERα expression, which could be reversed by miR-204 mimic transfection. When miR-204 is down regulated, the inhibition of TAM on breast cancer cells is enhanced. Caspase 3 activity is also increased. TSA and TAM combination inhibits Mcl-1 expression by decreasing phosphorylation of AKT induced by ERα increase in vivo and in vitro.

Low expression of microRNA-204 (miR-204) is associated with poor clinical outcome of acute myeloid leukemia (AML) patients

BACKGROUND

Acute myeloid leukemia (AML) is a heterogeneous neoplasm of the bone marrow with poor prognosis. In clinical practice new prognostic factors are still needed. MicroRNAs (miRs), small endogenous noncoding RNAs, play an essential role in the development and progression of acute leukemia. The aim of the study was to evaluate miR-204 expression in patients with AML at diagnosis and after induction chemotherapy, in comparison to healthy controls. We also investigated, if miR-204 expression correlates with clinical features of AML patients.

METHODS

miR-204 expression has been analyzed using RT-PCR in 95 bone marrow specimens from newly diagnosed AML patients in comparison to 20 healthy subject.

RESULTS

We showed down-regulated miR-204 expression in AML patients, which was associated with shorter patients' survival. Higher expression of miR-204 in patients after induction therapy was correlated with complete remission achieving.

CONCLUSIONS

We showed low miR-204 expression in AML and found it to be an independent prognostic factor in this patient population.

Triptolide abrogates growth of colon cancer and induces cell cycle arrest by inhibiting transcriptional activation of E2F

Despite significant progress in diagnostics and therapeutics, over 50 thousand patients die from colorectal cancer annually. Hence, there is urgent need for new lines of treatment. Triptolide, a natural compound isolated from the Chinese herb Tripterygium wilfordii, is effective against multiple cancers. We have synthesized a water soluble analog of triptolide, named Minnelide, which is currently in phase I trial against pancreatic cancer. The aims of the current study were to evaluate whether triptolide/Minnelide is effective against colorectal cancer and to elucidate the mechanism by which triptolide induces cell death in colorectal cancer. Efficacy of Minnelide was evaluated in subcutaneous xenograft and liver metastasis model of colorectal cancer. For mechanistic studies, colon cancer cell lines HCT116 and HT29 were treated with triptolide and the effect on viability, caspase activation, annexin positivity, lactate dehydrogenase release, and cell cycle progression was evaluated. Effect of triptolide on E2F transcriptional activity, mRNA levels of E2F-dependent genes, E2F1- retinoblastoma protein (Rb) binding, and proteins levels of regulator of G1-S transition was also measured. DNA binding of E2F1 was evaluated by chromatin immunoprecipitation assay. Triptolide decreased colon cancer cell viability in a dose- and time-dependent fashion. Minnelide markedly inhibited the growth of colon cancer in the xenograft and liver metastasis model of colon cancer and more than doubles the median survival of animals with liver metastases from colon cancer. Mechanistically, we demonstrate that at low concentrations triptolide induces apoptotic cell death but at higher concentrations it induces cell cycle arrest. Our data suggest that triptolide is able to induce G1 cell cycle arrest by inhibiting transcriptional activation of E2F1. Our data also show that triptolide downregulates E2F activity by potentially modulating events downstream of DNA binding. Therefore, we conclude that Triptolide and Minnelide are effective against colon cancer in multiple pre-clinical models.

MicroRNA-204 inhibits proliferation, migration, invasion and epithelial-mesenchymal transition in osteosarcoma cells via targeting Sirtuin 1

MicroRNAs (miRs) play crucial roles in tumorigenesis by directly suppressing the protein expression levels of their target genes. miR-204 has been suggested to act as a tumor suppressor in several types of human cancer. However, the exact role of miR-204 in osteosarcoma (OS) remains undetermined. In the present study, we aimed to investigate the effects of miR-204 on OS cell proliferation, migration and invasion, as well as the underlying molecular mechanisms. We found that the expression of miR-204 was frequently downregulated in four OS cell lines compared to the level in normal human osteoblast cells. Moreover, overexpression of miR-204 significantly inhibited the proliferation, migration and invasion of OS cells. Based on bioinformatics prediction and a luciferase reporter assay, we identified Sirtuin 1 (Sirt1) as a direct target gene of miR-204 in OS Saso-2 cells. Moreover, the protein expression of Sirt1 was negatively mediated by miR-204 in the OS cells. siRNA-mediated knockdown of Sirt1 also inhibited the proliferation, migration and invasion of the OS cells. Moreover, overexpression of Sirt1 reversed the inhibitory effect of miR-204 overexpression on the proliferation, migration and invasion of the OS cells. In addition, after miR-204 overexpression or Sirt1 knockdown in OS cells, the expression of E-cadherin was increased, while the N-cadherin protein level was reduced. Based on these findings, we suggest that miR-204 inhibits the proliferation, migration, invasion and epithelial-mesenchymal transition (EMT) of OS cells by directly targeting Sirt1.

Primary and liver metastasis-derived cell lines from KrasG12D; Trp53R172H; Pdx-1 Cre animals undergo apoptosis in response to triptolide

OBJECTIVES

Pancreatic cancer has a 5-year survival rate of less than 5%, partly because of limited chemotherapeutic options, thereby highlighting the need for novel therapies. Triptolide, a diterpene triepoxide that was derived from a Chinese herb, has shown great promise in preclinical testing against pancreatic cancer using immunocompromised animals.

RESULTS

In this study, we tested the ability of triptolide to induce cell death in cell lines derived from a primary tumor and adjacent liver metastases of immunocompetent animals (Kras, Trp53, Pdx-1 Cre [KPC]). Both cell lines were more aggressive in their ability to form tumors when compared with other pancreatic cancer cell lines and showed constitutive activation of the nuclear factor κ-light-chain-enhancer of activated B cells pathway. Triptolide induced apoptotic cell death in both cell lines, as evidenced by decreased cell viability as well as increased caspase 3/7 activity, annexin V positivity, and increased terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling positivity in tumors from KPC animals treated with Minnelide. In addition, triptolide decreased levels of HSP70, its transcription factor HSF1, as well as the antiapoptotic proteins Bcl-xL, Bcl-2, and Mcl-1, which are known to be up-regulated in pancreatic cancer.

CONCLUSIONS

The ability of triptolide to cause cell death in cell lines derived from immunocompetent animals further validates its potential as a novel agent against pancreatic cancer.

MicroRNAs in pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a devastating disease without effective treatment. Despite decades of research and the development of novel treatments, PAH remains a fatal disease, suggesting an urgent need for better understanding of the pathogenesis of PAH. Recent studies suggest that microRNAs (miRNAs) are dysregulated in patients with PAH and in experimental pulmonary hypertension. Furthermore, normalization of a few miRNAs is reported to inhibit experimental pulmonary hypertension. We have reviewed the current knowledge about miRNA biogenesis, miRNA expression pattern, and their roles in regulation of pulmonary artery smooth muscle cells, endothelial cells, and fibroblasts. We have also identified emerging trends in our understanding of the role of miRNAs in the pathogenesis of PAH and propose future studies that might lead to novel therapeutic strategies for the treatment of PAH.

Targeting mcl-1 for radiosensitization of pancreatic cancers

In order to identify targets whose inhibition may enhance the efficacy of chemoradiation in pancreatic cancer, we previously conducted an RNAi library screen of 8,800 genes. We identified Mcl-1 (myeloid cell leukemia-1), an anti-apoptotic member of the Bcl-2 family, as a target for sensitizing pancreatic cancer cells to chemoradiation. In the present study we investigated Mcl-1 inhibition by either genetic or pharmacological approaches as a radiosensitizing strategy in pancreatic cancer cells. Mcl-1 depletion by siRNA produced significant radiosensitization in BxPC-3 and Panc-1 cells in association with Caspase-3 activation and PARP cleavage, but only minimal radiosensitization in MiaPaCa-2 cells. We next tested the ability of the recently identified, selective, small molecule inhibitor of Mcl-1, UMI77, to radiosensitize in pancreatic cancer cells. UMI77 caused dissociation of Mcl-1 from the pro-apoptotic protein Bak and produced significant radiosensitization in BxPC-3 and Panc-1 cells, but minimal radiosensitization in MiaPaCa-2 cells. Radiosensitization by UMI77 was associated with Caspase-3 activation and PARP cleavage. Importantly, UMI77 did not radiosensitize normal small intestinal cells. In contrast, ABT-737, an established inhibitor of Bcl-2, Bcl-XL, and Bcl-w, failed to radiosensitize pancreatic cancer cells suggesting the unique importance of Mcl-1 relative to other Bcl-2 family members to radiation survival in pancreatic cancer cells. Taken together, these results validate Mcl-1 as a target for radiosensitization of pancreatic cancer cells and demonstrate the ability of small molecules which bind the canonical BH3 groove of Mcl-1, causing displacement of Mcl-1 from Bak, to selectively radiosensitize pancreatic cancer cells.

The Role of Nutraceuticals in Pancreatic Cancer Prevention and Therapy: Targeting Cellular Signaling, MicroRNAs, and Epigenome

Pancreatic cancer is one of the most aggressive malignancies in US adults. Experimental studies have found that antioxidant nutrients could reduce oxidative DNA damage, suggesting that these antioxidants may protect against pancreatic carcinogenesis. Several epidemiologic studies showed that dietary intake of antioxidants was inversely associated with the risk for pancreatic cancer, demonstrating the inhibitory effects of antioxidants on pancreatic carcinogenesis. Moreover, nutraceuticals, the anticancer agents from diet or natural plants, have been found to inhibit the development and progression of pancreatic cancer through the regulation of cellular signaling pathways. Importantly, nutraceuticals also up-regulate the expression of tumor-suppressive microRNAs (miRNAs) and down-regulate the expression of oncogenic miRNAs, leading to the inhibition of pancreatic cancer cell growth and pancreatic cancer stem cell self-renewal through modulation of cellular signaling network. Furthermore, nutraceuticals also regulate epigenetically deregulated DNAs and miRNAs, leading to the normalization of altered cellular signaling in pancreatic cancer cells. Therefore, nutraceuticals could have much broader use in the prevention and/or treatment of pancreatic cancer in combination with conventional chemotherapeutics. However, more in vitro mechanistic experiments, in vivo animal studies, and clinical trials are needed to realize the true value of nutraceuticals in the prevention and/or treatment of pancreatic cancer.