MACC1 is post-transcriptionally regulated by miR-218 in colorectal cancer. Oncotarget. 2016;7:53443-53458. [PMID: 27462788 PMCID: PMC5288198 DOI: 10.18632/oncotarget.10803]

Coding roles of long non-coding RNAs in breast cancer: Emerging molecular diagnostic biomarkers and potential therapeutic targets with special reference to chemotherapy resistance

Dysregulation of epigenetic mechanisms have been depicted in several pathological consequence such as cancer. Different modes of epigenetic regulation (DNA methylation (hypomethylation or hypermethylation of promotor), histone modifications, abnormal expression of microRNAs (miRNAs), long non-coding RNAs, and small nucleolar RNAs), are discovered. Particularly, lncRNAs are known to exert pivot roles in different types of cancer including breast cancer. LncRNAs with oncogenic and tumour suppressive potential are reported. Differentially expressed lncRNAs contribute a remarkable role in the development of primary and acquired resistance for radiotherapy, endocrine therapy, immunotherapy, and targeted therapy. A wide range of molecular subtype specific lncRNAs have been assessed in breast cancer research. A number of studies have also shown that lncRNAs may be clinically used as non-invasive diagnostic biomarkers for early detection of breast cancer. Such molecular biomarkers have also been found in cancer stem cells of breast tumours. The objectives of the present review are to summarize the important roles of oncogenic and tumour suppressive lncRNAs for the early diagnosis of breast cancer, metastatic potential, and chemotherapy resistance across the molecular subtypes.

Elevated MACC1 Expression in Colorectal Cancer Is Driven by Chromosomal Instability and Is Associated with Molecular Subtype and Worse Patient Survival

Metastasis-Associated in Colon Cancer 1 (MACC1) is a strong prognostic biomarker inducing proliferation, migration, invasiveness, and metastasis of cancer cells. The context of MACC1 dysregulation in cancers is, however, still poorly understood. Here, we investigated whether chromosomal instability and somatic copy number alterations (SCNA) frequently occurring in CRC contribute to MACC1 dysregulation, with prognostic and predictive impacts. Using the Oncotrack and Charité CRC cohorts of CRC patients, we showed that elevated MACC1 mRNA expression was tightly dependent on increased MACC1 gene SCNA and was associated with metastasis and shorter metastasis free survival. Deep analysis of the COAD-READ TCGA cohort revealed elevated MACC1 expression due to SCNA for advanced tumors exhibiting high chromosomal instability (CIN), and predominantly classified as CMS2 and CMS4 transcriptomic subtypes. For that cohort, we validated that elevated MACC1 mRNA expression correlated with reduced disease-free and overall survival. In conclusion, this study gives insights into the context of MACC1 expression in CRC. Increased MACC1 expression is largely driven by CIN, SCNA gains, and molecular subtypes, potentially determining the molecular risk for metastasis that might serve as a basis for patient-tailored treatment decisions.

Alternative polyadenylation: An enigma of transcript length variation in health and disease

Alternative polyadenylation (APA) is a molecular mechanism during a pre-mRNA processing that involves usage of more than one polyadenylation site (PA-site) generating transcripts of varying length from a single gene. The location of a PA-site affects transcript length and coding potential of an mRNA contributing to both mRNA and protein diversification. This variation in the transcript length affects mRNA stability and translation, mRNA subcellular and tissue localization, and protein function. APA is now considered as an important regulatory mechanism in the pathophysiology of human diseases. An important consequence of the changes in the length of 3'-untranslated region (UTR) from disease-induced APA is altered protein expression. Yet, the relationship between 3'-UTR length and protein expression remains a paradox in a majority of diseases. Here, we review occurrence of APA, mechanism of PA-site selection, and consequences of transcript length variation in different diseases. Emerging evidence reveals coordinated involvement of core RNA processing factors including poly(A) polymerases in the PA-site selection in diseases-associated APAs. Targeting such APA regulators will be therapeutically significant in combating drug resistance in cancer and other complex diseases. This article is categorized under: RNA Processing > 3' End Processing RNA in Disease and Development > RNA in Disease Translation > Regulation.

The newly identified MEK1 tyrosine phosphorylation target MACC1 is druggable by approved MEK1 inhibitors to restrict colorectal cancer metastasis

Cancer metastasis causes >90% of cancer deaths and remains a major treatment challenge. Here we deciphered the impact of tyrosine phosphorylation of MACC1, a causative driver for cancer metastasis, for cancer cell signaling and novel interventions to restrict cancer metastasis. We identified MACC1 as new MEK1 substrate. MEK1 directly phosphorylates MACC1, leading to accelerated and increased ERK1 activation. Mutating in silico predicted hierarchical MACC1 tyrosine phosphorylation sites abrogates MACC1-induced migration, invasion, and MET expression, a transcriptional MACC1 target. Targeting MEK1 by RNAi or clinically applicable MEK1 inhibitors AZD6244 and GSK1120212 reduces MACC1 tyrosine phosphorylation and restricts MACC1-induced metastasis formation in mice. Although MEK1 levels, contrary to MACC1, are not of prognostic relevance for CRC patients, MEK1 expression was found indispensable for MACC1-induced metastasis. This study identifies MACC1 as new MEK1 substrate for tyrosine phosphorylation decisively impacting cell motility, tumor growth, and metastasis. Thus, MAP kinase signaling is not linear leading to ERK activation, but branches at the level of MEK1. This fundamental finding opens new therapeutic options for targeting the MEK1/MACC1 axis as novel vulnerability in patients at high risk for metastasis. This might be extended from CRC to further solid tumor entities.

Circ_0006174 Accelerates Colorectal Cancer Progression Through Regulating miR-138-5p/MACC1 Axis

Background

Circular RNAs (circRNAs) were reported to be involved in the progression of a variety of cancers, including colorectal cancer (CRC). However, the precise functions and mechanism of circRNAs in CRC have not been elucidated. This study aimed to investigate the effect and mechanism underlying circ_0006174 in CRC.

Methods

The expression of circ_0006174, microRNA (miR-138-5p) and metastasis associated in colon cancer 1 (MACC1) mRNA was detected by quantitative real-time polymerase chain reaction (RT-qPCR) assay. Western blot was employed to measure MACC1 protein expression. The effects of circ_0006174 knockdown, MACC1 overexpression or miR-138-5p inhibition on cell proliferation, migration, invasion, and apoptosis were assessed by cell counting kit 8 (CCK-8) assay, clone formation assay, transwell assay and flow cytometry assay, respectively. The interaction between miR-138-5p and circ_0006174 or MACC1 was confirmed by RNA pull down assay or dual-luciferase reporter assay. Xenograft tumor model in nude mice was used to verify the function of circ_0006174 in vivo.

Results

Circ_0006174 and MACC1 expression was highly expressed, while miR-138-5p expression was downregulated in CRC cells and tissues. Meanwhile, circ_0006174 functioned as a sponge of miR-138-5p to upregulate MACC1 expression. Furthermore, circ_0006174 knock down-mediated suppression on cell proliferation, migration and invasion, and promotion on cell apoptosis could be alleviated by MACC1 overexpression or miR-138-5p inhibition in CRC cells. Besides, circ_0006174 knockdown also inhibited CRC procession in vivo.

Conclusion

Circ_0006174 advanced CRC progression via sponging miR-138-5p to upregulate MACC1 expression, which may provide a promising molecular target for CRC treatment.

Long non‑coding RNA fer‑1‑like family member 4 serves as a tumor suppressor in laryngeal squamous cell carcinoma cells via regulating the AKT/ERK signaling pathway

Laryngeal squamous cell carcinoma (LSCC) is a common type of malignant tumor of the head and neck. An increasing number of studies have illustrated that long non-coding RNAs (lncRNAs) serve an important role in the occurrence and development of LSCC. Therefore, the present study aimed to investigate the expression changes and mechanism of lncRNA fer-1-like family member 4 (FER1L4) in the progression of LSCC. The expression levels of FER1L4 in LSCC cell lines (AMC-HN-8, Tu 686, M4E and M2E) and a normal cell line (HBE135-E6E7) were analyzed using reverse transcription-quantitative PCR. The FER1L4 overexpression plasmid (plasmid-FER1L4) was subsequently transfected into Tu 686 cells to upregulate the expression levels of FER1L4. Cell viability was detected using a Cell Counting Kit-8 assay, cell proliferation was analyzed using a colony formation assay, apoptosis was examined by flow cytometry, and cell migration and invasion were determined using wound healing and Transwell assays, respectively. In addition, the plasmid-FER1L4 cells were also treated with insulin-like growth factor 1 (IGF-1) to determine the effect of FER1L4 on the AKT/ERK signaling pathway, and the effect of the plasmid-FER1L4 on the expression levels of AKT/ERK signaling pathway-related proteins were analyzed using western blotting. The results of the present study revealed that FER1L4 expression levels were downregulated in AMC-HN-8 and Tu 686 cells. Notably, FER1L overexpression significantly reduced the cell viability, proliferation, migration and invasion of LSCC cells, while promoting apoptosis. Meanwhile, the plasmid-FER1L4 also significantly suppressed the phosphorylation levels of AKT and ERK. Further studies indicated that the aforementioned changes could be reversed by IGF-1, indicating FER1L4 may regulate the progression of LSCC cells by inhibiting the AKT/ERK signaling pathway. In conclusion, the present study provided a potential novel direction for the treatment of LSCC in the future and suggested that FER1L4 may be a new target in this field.

Restoring Treatment Response in Colorectal Cancer Cells by Targeting MACC1-Dependent ABCB1 Expression in Combination Therapy

Treatment failure of solid cancers, represented by the development of drug resistance in the primary tumor or later outgrowth of drug resistant metastases, is the major cause of death for cancer patients. It represents an urgent clinical need for predictive biomarkers which indicate the success or failure of standard treatment regimens. Besides treatment prediction, interfering with cellular processes associated with drug resistance might improve treatment response by applying combination therapies. Metastasis-associated in colon cancer (MACC) 1 was identified in our group as a prognostic biomarker in human colorectal cancer, and has been established as key player, prognostic, and predictive biomarker for tumor progression and metastasis in a variety of solid cancers. Besides increased cell proliferation and motility, subsequently contributing to growth and metastatic spread of the primary tumor, MACC1 has also been shown to dysregulate apoptosis and is contributing to treatment resistance. Here we report the MACC1 dependent treatment resistance of colorectal cancer (CRC) cells to standard therapeutics like doxorubicin by upregulating ATP-binding cassette subfamily B member 1 (ABCB1) protein. Overexpression of MACC1 in CRC cells increased both its presence on the ABCB1 promoter and its transcriptional activity, resulting in elevated ABCB1 expression and thus treatment resistance to standard therapeutics. In contrast, depleting MACC1 increased intracellular drug concentrations, leading to better treatment response. We already identified the first MACC1 transcriptional inhibitors, such as lovastatin, by high-throughput screening of clinically approved small molecule drugs. These compounds inhibited cell motility in vitro but also restricted metastasis development in xenograft mouse models by reducing MACC1 expression. Here we report, that treating high MACC1 expressing CRC cells with a combination of statins and standard therapeutics increased the rate of cytotoxicity and resulted in higher treatment response.

Decoding and targeting the molecular basis of MACC1-driven metastatic spread: Lessons from big data mining and clinical-experimental approaches

Metastasis remains the key issue impacting cancer patient survival and failure or success of cancer therapies. Metastatic spread is a complex process including dissemination of single cells or collective cell migration, penetration of the blood or lymphatic vessels and seeding at a distant organ site. Hundreds of genes involved in metastasis have been identified in studies across numerous cancer types. Here, we analyzed how the metastasis-associated gene MACC1 cooperates with other genes in metastatic spread and how these coactions could be exploited by combination therapies: We performed (i) a MACC1 correlation analysis across 33 cancer types in the mRNA expression data of TCGA and (ii) a comprehensive literature search on reported MACC1 combinations and regulation mechanisms. The key genes MET, HGF and MMP7 reported together with MACC1 showed significant positive correlations with MACC1 in more than half of the cancer types included in the big data analysis. However, ten other genes also reported together with MACC1 in the literature showed significant positive correlations with MACC1 in only a minority of 5 to 15 cancer types. To uncover transcriptional regulation mechanisms that are activated simultaneously with MACC1, we isolated pan-cancer consensus lists of 1306 positively and 590 negatively MACC1-correlating genes from the TCGA data and analyzed each of these lists for sharing transcription factor binding motifs in the promotor region. In these lists, binding sites for the transcription factors TELF1, ETS2, ETV4, TEAD1, FOXO4, NFE2L1, ELK1, SP1 and NFE2L2 were significantly enriched, but none of them except SP1 was reported in combination with MACC1 in the literature. Thus, while some of the results of the big data analysis were in line with the reported experimental results, hypotheses on new genes involved in MACC1-driven metastasis formation could be generated and warrant experimental validation. Furthermore, the results of the big data analysis can help to prioritize cancer types for experimental studies and testing of combination therapies.

Circulating MACC1 Transcripts in Glioblastoma Patients Predict Prognosis and Treatment Response

Glioblastoma multiforme is the most aggressive primary brain tumor of adults, but lacks reliable and liquid biomarkers. We evaluated circulating plasma transcripts of metastasis-associated in colon cancer-1 (MACC1), a prognostic biomarker for solid cancer entities, for prediction of clinical outcome and therapy response in glioblastomas. MACC1 transcripts were significantly higher in patients compared to controls. Low MACC1 levels clustered together with other prognostically favorable markers. It was associated with patients’ prognosis in conjunction with the isocitrate dehydrogenase (IDH) mutation status: IDH1 R132H mutation and low MACC1 was most favorable (median overall survival (OS) not yet reached), IDH1 wildtype and high MACC1 was worst (median OS 8.1 months), while IDH1 wildtype and low MACC1 was intermediate (median OS 9.1 months). No patients displayed IDH1 R132H mutation and high MACC1. Patients with low MACC1 levels receiving standard therapy survived longer (median OS 22.6 months) than patients with high MACC1 levels (median OS 8.1 months). Patients not receiving the standard regimen showed the worst prognosis, independent of MACC1 levels (low: 6.8 months, high: 4.4 months). Addition of circulating MACC1 transcript levels to the existing prognostic workup may improve the accuracy of outcome prediction and help define more precise risk categories of glioblastoma patients.

MicroRNA expression profiling in the colorectal normal-adenoma-carcinoma transition

Colorectal adenoma is a major precursor to colorectal cancer. Investigating the alteration of microRNA (miRNA/miR) expression during the progression from normal colorectal tissue to adenoma, and finally to colorectal carcinoma may aid our understanding of the biological mechanisms of colorectal tumorigenesis. In the present study, the miRNA expression profiles of normal colorectal tissue, adenoma and colorectal carcinoma from 6 patients were evaluated using miRNA-sequencing. A total of 334 miRNAs were identified as differentially expressed. It was revealed that 34 miRNAs were upregulated in all 6 patients, including miR-135b-5p, miR-18a-5p and miR-29b-3p, and 28 miRNAs were downregulated, including miR-1-3p, miR-338-3p and miR-218-5p. Using bioinformatic analysis, the potential target genes of these 62 miRNAs were predicted and found to be enriched in 'transcription, DNA-dependent (GO:0006351)', 'signal transduction (GO:0007165)', 'small molecule metabolic process (GO:0044281)' 'PI3K/AKT signaling pathway (path ID:04151)' and 'MAPK signaling pathway (path ID:04010)'. The miRNA expression profiles identified in the present study may extend our understanding of the molecular mechanisms underlying colorectal tumorigenesis and promote novel perspectives for prevention, diagnosis and treatment.

Downregulation of lncRNA CCAT1 enhances 5-fluorouracil sensitivity in human colon cancer cells

BACKGROUND

The purpose of this study was to determine the aberrant expression of the long noncoding RNA (lncRNA) colon cancer-associated transcript 1 (CCAT1) in 5-fluorouracil-resistant colonic neoplasm cells and to elucidate its effects on the 5-fluorouracil sensitivity of human colonic neoplasm cells. The aberrant expression of lncRNAs in normal tissues and colonic neoplasm tissues was detected by microarray assay. qRT-PCR analysis was performed to assess CCAT1 expression levels in colonic neoplasm cell lines and corresponding normal tissues. After constructing the 5-FU-resistant cell lines and validating the resistance by measuring the IC₅₀ value, the CCAT1 expression levels in parental and artificially resistant cell lines were determined by qRT-PCR. Transfection was used to modulate the expression of CCAT1. Cell proliferation and apoptosis were then detected by CCK-8 and flow cytometry, respectively.

RESULTS

CCAT1 in colon cancer tissues was higher than that in noncancer tissues, and the levels of CCAT1 in HCT 116, SW1417, HT-29, and KM12 cell lines were higher than those in the human normal colon epithelial NCM460 cell line. Moreover, the expression levels of CCAT1 were high in HCT 116/5-FU and HT-29/5-FU cell lines, whose apoptosis rates induced by 5-FU were lower than those in corresponding parental cells. The results of qRT-PCR and CCK-8 assay showed that enhancement of lncRNA CCAT1 expression levels in HCT 116 and HT-29 cell lines increased their IC₅₀ of 5-FU and decreased their apoptosis rates. Meanwhile, siRNA-CCAT1 effectively inhibited the expression of CCAT1 and enhanced the 5-FU-sensitivity of HCT 116/5-FU and HT-29/5-FU, in which apoptosis rates were increased at the same time.

CONCLUSIONS

Downregulation of CCAT1 effectively reversed the resistance of HCT 116/5-FU and HT-29/5-FU cells to 5-FU chemotherapeutic, opening a new avenue in colon cancer therapy.

MACC1-the first decade of a key metastasis molecule from gene discovery to clinical translation

Deciphering the paths to metastasis and identifying key molecules driving this process is one important issue for understanding and treatment of cancer. Such a key driver molecule is Metastasis Associated in Colon Cancer 1 (MACC1). A decade long research on this evolutionarily conserved molecule with features of a transcription factor as well as an adapter protein for versatile protein-protein interactions has shown that it has manifold properties driving tumors to their metastatic stage. MACC1 transcriptionally regulates genes involved in epithelial-mesenchymal transition (EMT), including those which are able to directly induce metastasis like c-MET, impacts tumor cell migration and invasion, and induces metastasis in solid cancers. MACC1 has proven as a valuable biomarker for prognosis of metastasis formation linked to patient survival and gives promise to also act as a predictive marker for individualized therapies in a broad variety of cancers. This review discusses the many features of MACC1 in the context of the hallmarks of cancer and the potential of this molecule as biomarker and novel therapeutic target for restriction and prevention of metastasis.

Oncogenic and Tumor-Suppressive Roles of MicroRNAs with Special Reference to Apoptosis: Molecular Mechanisms and Therapeutic Potential

MicroRNAs (miRNAs) are the non-coding class of minute RNA molecules that negatively control post-transcriptional regulation of various functional genes. These miRNAs are transcribed from the loci present in the introns of functional or protein-coding genes, exons of non-coding genes, or even in the 3'-untranslated region (3'-UTR). They have potential to modulate the stability or translational efficiency of a variety of target RNA [messenger RNA (mRNA)]. The regulatory function of miRNAs has been elucidated in several pathological conditions, including neurological (Alzheimer's disease and Parkinson's disease) and cardiovascular conditions, along with cancer. Importantly, miRNA identification in cancer progression and invasion has evolved as an incipient era in cancer treatment. Several studies have shown the influence of miRNAs on various cancer processes, including apoptosis, invasion, metastasis and angiogenesis. In particular, apoptosis induction in tumor cells through miRNA has been extensively studied. The biphasic mode (up- and down-regulation) of miRNA expression in apoptosis and other cancer processes has already been determined. The findings of these studies could be utilized to develop potential therapeutic strategies for the management of various cancers. The present review critically describes the oncogenic and tumor suppressor role of miRNAs in apoptosis and other cancer processes, therapy resistance, and use of their presence in the body fluids as biomarkers.

MiR-218 regulates epithelial-mesenchymal transition and angiogenesis in colorectal cancer via targeting CTGF

Background

Endothelial-to-mesenchymal transition (EMT) and angiogenesis play important roles in colorectal cancer (CRC) development. Connective tissue growth factor (CTGF) has been reported to promote several kinds of cancer progression and miR-218 has been identified as a tumor suppressor miRNA. However, little is known about the function of miR-218 in CRC. Here we investigated the effects of miR-218 on EMT and angiogenesis process in CRC cells. As well, the relation between miR-218 and CTGF was identified. The mechanism of miR-218’s function was illustrated.

Methods

CRC cell lines were transfected with miR-218 mimics. Proliferation, migration and angiogenesis were identified by MTT assay, Transwell assay, colony formation assay and tube formation assay. Protein and mRNA expression levels of associated genes were measured by Western blotting and RT-PCR. Dual luciferase assay was used to determine the relation of miR-218 and CTGF.

Results

miR-218 was down-regulated in CRC cell lines and over expression of miR-218 could significantly inhibit EMT and angiogenesis. CTGF was a direct target of miR-218. Up regulation of CTGF level after miR-218 transfection could sufficiently rescue the suppression effects on EMT and angiogenesis.

Conclusion

miR-218 directly targets CTGF and inhibits its expression, leading to suppression on EMT and angiogenesis of CRC cells. miR-218 might be used as potential therapeutic strategy for CRC treatment.

Differential miRNA expression profiling reveals miR-205-3p to be a potential radiosensitizer for low- dose ionizing radiation in DLD-1 cells

Enhanced radiosensitivity at low doses of ionizing radiation (IR) (0.2 to 0.6 Gy) has been reported in several cell lines. This phenomenon, known as low doses hyper-radiosensitivity (LDHRS), appears as an opportunity to decrease toxicity of radiotherapy and to enhance the effects of chemotherapy. However, the effect of low single doses IR on cell death is subtle and the mechanism underlying LDHRS has not been clearly explained, limiting the utility of LDHRS for clinical applications. To understand the mechanisms responsible for cell death induced by low-dose IR, LDHRS was evaluated in DLD-1 human colorectal cancer cells and the expression of 80 microRNAs (miRNAs) was assessed by qPCR array. Our results show that DLD-1 cells display an early DNA damage response and apoptotic cell death when exposed to 0.6 Gy. miRNA expression profiling identified 3 over-expressed (miR-205-3p, miR-1 and miR-133b) and 2 down-regulated miRNAs (miR-122-5p, and miR-134-5p) upon exposure to 0.6 Gy. This miRNA profile differed from the one in cells exposed to high-dose IR (12 Gy), supporting a distinct low-dose radiation-induced cell death mechanism. Expression of a mimetic miR-205-3p, the most overexpressed miRNA in cells exposed to 0.6 Gy, induced apoptotic cell death and, more importantly, increased LDHRS in DLD-1 cells. Thus, we propose miR-205-3p as a potential radiosensitizer to low-dose IR.

Epigenetic silencing of miR-520c leads to induced S100A4 expression and its mediated colorectal cancer progression

The S100 calcium-binding protein A4 (S100A4) induces epithelial mesenchymal transition, migration, invasion, angiogenesis and metastasis. Its induced expression in several cancer types correlates with poor prognosis. Apart from the functional and transcriptional regulatory aspects of S100A4, its post-transcriptional regulation is not yet clearly elucidated. In this study, we show that microRNAs (miR) miR-505-5p and miR-520c-3p target the 3′-UTR of S100A4 and inhibits its expression and its mediated migration and invasion. 5-Aza treatment significantly increased miR-520c-3p expression and reduced the S100A4 protein amounts. The upstream promoter region of miR-520c is hypermethylated irrespective of the metastasis status of colorectal cancer (CRC) patient tissues and in all analyzed CRC cell lines. Moreover, in a cohort of CRC patient specimen (n = 59), miR-520c-3p was significantly downregulated. miR-520c-3p stably expressing HCT116 cells showed a reduced metastasis formation in livers after implanting in mice spleen. Taken together, our findings demonstrate that S100A4 is post-transcriptionally regulated by tumor suppressor miRs, miR-505c-5p and miR-520c-3p, and particularly miR-520c-3p expression is epigenetically silenced in CRC.

MACC1 induces autophagy to regulate proliferation, apoptosis, migration and invasion of squamous cell carcinoma

Metastasis-associated colon cancer-1 (MACC1) plays an important role in cancer development, but the role and mechansim of MACC1 in squamous cell carcinoma (ESCC) remain unclear. In this study, we found that MACC1 expression was increased in ESCC, and correlated with lymph node metastasis. MACC1 knockdown suppresed ESCC cell proliferation, metastasis and enchanced cell apoptosis. Moreover, MACC1 knockdown inhibited ESCC cell autophagy, and 3-methyladenine was able to rescue MACC1-induced malignant phenotype of ESCC cells. Furthermore, MACC1 knockdown inactivated AMPK-ULK1 signaling pathway, and metformin could rescue MACC1-induced autophagy in ESCC cells. Collectively, this study found that upregulation of MACC1 in ESCC was associated with lymph node metastasis of patients, and MACC1 regulated ESCC cell proliferation, apoptosis, migration and invasion mainly through AMPK-ULK1 induced autophagy.

MicroRNAs as a tool to aid stratification of colorectal cancer patients and to guide therapy

Colorectal cancer is a common type of malignant disease with high rates of morbidity and mortality. Although treatment options have been expanded over the last years, the mainstay of curative treatment remains surgical removal of the tumor-bearing organ. Systemic treatment options include classic cytotoxic drugs as well as some biological agents. Noncoding RNAs are an evolving field in cancer diagnosis, prognosis and possible treatment. Noncoding miRNAs are small molecules with huge impact on gene expression. They have been a substantial part of cancer research for more than a decade. In this review article, the current knowledge of miRNAs and colorectal cancer diagnosis, prognosis and novel or evolving therapeutic concepts are discussed. Examples of how miRNAs might change the management of the disease will be described.

MicroRNAs: Potential candidates for diagnosis and treatment of colorectal cancer

Colorectal cancer (CRC) is known as the third common cancer worldwide and an important public health problem in different populations. Several genetics and environmental risk factors are involved in the development and progression of CRC including chromosomal abnormalities, epigenetic alterations, and unhealthy lifestyle. Identification of risk factors and biomarkers could lead to a better understanding of molecular pathways involved in CRC pathogenesis. MicroRNAs (miRNAs) are important regulatory molecules which could affect a variety of cellular and molecular targets in CRC. A large number of studies have indicated deregulations of some known tissue-specific miRNAs, for example, miR-21, miR-9, miR-155, miR-17, miR-19, let-7, and miR-24 as well as circulating miRNAs, for example, miR-181b, miR-21, miR-183, let-7g, miR-17, and miR-126, in patients with CRC. In the current review, we focus on the findings of preclinical and clinical studies performed on tissue-specific and circulating miRNAs as diagnostic biomarkers and therapeutic targets for the detection of patients at various stages of CRC.

MiR-218 suppresses the metastasis and EMT of HCC cells via targeting SERBP1

Hepatocellular carcinoma (HCC) is the leading cause of cancer-related deaths worldwide. Although many efforts for treating HCC have been made, the survival rate remains unsatisfied. Accumulating evidence indicates that microRNA-218 (miR-218) functions as a tumor suppressor and involves in many biological processes such as tumor initiation, development, and metastasis in certain types of human cancers. However, the potential function and underlying molecular mechanism of miR-218 in HCC still remains to be elucidated. Since HCC is a genetic disease, exploring the mechanisms of the pathogeny and integration are essential for the discovery of novel treatment targets for HCC. Therefore, the aim of the present study was to investigate the abnormal expression level of miR-218 in clinical HCC tissues and HCC cells, and to evaluate its function and underlying mechanisms in HCC. Our results revealed that miR-218 expression was significantly downregulated in HCC tissues and cell lines. Gain-of-function and loss-of-function assays indicated that forced expression of miR-218 in HCC cells inhibited cell migration/invasion and reversed epithelial-mesenchymal transition (EMT) to mesenchymal-epithelial transition (MET), while deletion of miR-218 promoted cell migration/invasion and contributed to the EMT phenotype formation. Bioinformatics analysis and luciferase reporter assay confirmed that serpine mRNA binding protein 1 (SERBP1) was a target gene of miR-218 and rescue assay further confirmed that SERBP1 involved in the function of miR-218 in HCC. All these results suggested that miR-218/SERBP1 signal pathway could inhibit the malignant phenotype formation and that targeting this pathway may be a potential novel way for HCC therapeutics.

MACC1 regulatory network in tumor metastasis

The MACC1 gene was firstly identified in colorectal cancer. Recently, abnormal upregulation of MACC1 has been detected in multiple tumors. The expression of MACC1 is shown to be positively associated with tumor metastasis, but negatively with prognosis of patients, and it represents a potential therapeutic target for anti-tumor strategies. MACC1 has increasingly emerged as a key regulator in metastatic processes, and it has been identified to be able to maintain multiple tumor-associated signaling pathways, transactivate oncogenic genes, and regulate epithelial-mesenchymal transition and tumor vascularization. On the other hand, MACC1 is regulated and influenced by non-coding RNAs and SNPs. The present review will summarize the recent progress in understanding the role of the MACC1 regulatory network in tumor metastasis.