MicroRNA expression profiling identifies miR-328 regulates cancer stem cell-like SP cells in colorectal cancer

Diverse functions of miR-328 in the carcinogenesis

MicroRNA-328 (miR-328) is an RNA gene that is primarily associated with lung cancer, and its encoding gene is located on 16q22.1. Expression of miR-328 has been observed in lung and esophagus tissues based on RNAseq data. Although several studies have aimed at the detection of miR-328 levels in tumor tissues, there is an obvious discrepancy between the results of these studies. Even in a certain type of cancer, some studies have reported up-regulation of miR-328 in cancerous tissues versus control tissues, while others have reported its down-regulation. This discrepancy might be attributed to different stages/grades of tumor tissues or other clinical characteristics. This review article focuses on the available literature to explore the functions of miR-328 in the development of human carcinogenesis.

Haplotype-GGGT in long non-coding RNA MALAT1 inhibits brain metastatic lung cancer and lymph nodes of lung cancer via the MALAT1/miR-328/KATNB1

The up-regulation of Katanin P8 has been reported to be correlated with a larger tumor size and lymph node metastasis in non-small-cell lung cancer (NSCLC) patients. And lncRNA MALAT1 was demonstrated to promote the proliferation of chronic myeloid leukemia cells via modulating miR-328. 135 lung cancer patients were divided into 6 groups according to their genotypes of MALAT1. The expression of KATNB1 was negatively correlated with the GGGT genotype of MALAT1. Decreased lymph node size and tumor size of brain metastatic lung were observed in patients with GGGT genotype of MALAT1. The luciferase activities of MALAT1 and KATNB1 were remarkably suppressed by miR-328 in A549 and H460. And the down-regulation of MALAT1 or up-regulation of miR-328 significantly repressed the KATNB1 expression in A549 and H460 cells. MALAT1 expression was reduced in patients carrying haplotype GGGT. A signaling pathway of MALAT1/miR-328/KATNB1 was established to explain the down-regulation of KATNB1 mRNA in patients carrying haplotype GGGT and reduced lymph node size in lung cancer and tumor size in brain metastatic lung cancer.

The Relationship between Serum miRNAs and Early Mortality in Multiple Myeloma Patients Treated with Bortezomib-Based Regimens

Multiple myeloma (MM) is a hematological malignancy characterized by the clonal proliferation of plasma cells in the bone marrow (BM) microenvironment. Despite the progress made in treatment, some MM patients still die within the first year of diagnosis. Numerous studies investigating microRNA (miRNA) expression patterns suggest they may be good prognostic markers. The primary aim of this study was to analyze the expression of selected miRNAs in the serum of MM patients who were later treated with bortezomib-based regimens, and to determine their potential to predict early mortality. The study was conducted in 70 prospectively recruited patients with newly diagnosed MM admitted to the Department of Hematology of the Copernicus Memorial Hospital, Lodz (Poland) between 2017 and 2021. Among them, 17 patients experienced death within 12 months of diagnosis. The expression of 31 selected miRNAs was determined using a miRCURY LNA miRNA Custom PCR Panel. The obtained clinical data included patient characteristics on diagnosis, treatment regimen, response to treatment, and follow-up. Differential expression analysis found two miRNAs to be significantly downregulated in the early mortality group: hsa-miR-328-3p (fold change-FC: 0.72, p = 0.0342) and hsa-miR-409-3p (FC: 0.49, p = 0.0357). Univariate and multivariate logistic regression analyses were performed to assess the early mortality rate. The final model consisted of hsa-miR-409-3p, hsa-miR-328-3p, age, and R-ISS 3. It yielded an area under the curve (AUC) of 0.863 (95%CI: 0.761-0.965) with 88.2% sensitivity and 77.5% specificity. Further external validation of our model is needed to confirm its clinical value.

The diagnostic, prognostic role and molecular mechanism of miR-328 in human cancer

MicroRNA are non-coding small RNAs that bind to their target mRNA and cause mRNA degradation or translation inhibition. MiRNA dysregulation is linked to a variety of human cancers and has a role in the genesis and development of cancer pathology. MiR-328 has been reported to be involved in various human cancers. And miR-328 is considered a key regulator in human cancer. It participates in biological processes such as proliferation, apoptosis, invasion, migration, and EMT. The present review will combine the basic and clinical studies to find that miR-328 promotes tumorigenesis and metastasis in human cancer. And we will describe the diagnostic, prognostic, and therapeutic value of miR-328 in various human cancers.

A Systematic Review of Clinical Validated and Potential miRNA Markers Related to the Efficacy of Fluoropyrimidine Drugs

Colorectal cancer (CRC) is becoming increasingly prevalent worldwide. Fluoropyrimidine drugs are the primary chemotherapy regimens in routine clinical practice of CRC. However, the survival rate of patients on fluoropyrimidine-based chemotherapy varies significantly among individuals. Biomarkers of fluoropyrimidine drugs'' efficacy are needed to implement personalized medicine. This review summarized fluoropyrimidine drug-related microRNA (miRNA) by affecting metabolic enzymes or showing the relevance of drug efficacy. We first outlined 42 miRNAs that may affect the metabolism of fluoropyrimidine drugs. Subsequently, we filtered another 41 miRNAs related to the efficacy of fluoropyrimidine drugs based on clinical trials. Bioinformatics analysis showed that most well-established miRNA biomarkers were significantly enriched in the cancer pathways instead of the fluoropyrimidine drug metabolism pathways. The result also suggests that the miRNAs screened from metastasis patients have a more critical role in cancer development than those from non-metastasis patients. There are five miRNAs shared between these two lists. The miR-21, miR-215, and miR-218 can suppress fluoropyrimidine drugs'' catabolism. The miR-326 and miR-328 can reduce the efflux of fluoropyrimidine drugs. These five miRNAs could jointly act by increasing intracellular levels of fluoropyrimidine drugs'' cytotoxic metabolites, leading to better chemotherapy responses. In conclusion, we demonstrated that the dynamic changes in the transcriptional regulation via miRNAs might play significant roles in the efficacy and toxicity of the fluoropyrimidine drug. The reported miRNA biomarkers would help evaluate the efficacy of fluoropyrimidine drug-based chemotherapy and improve the prognosis of colorectal cancer patients.

Multidrug efflux transporter ABCG2: expression and regulation

The adenosine triphosphate (ATP)-binding cassette efflux transporter G2 (ABCG2) was originally discovered in a multidrug-resistant breast cancer cell line. Studies in the past have expanded the understanding of its role in physiology, disease pathology and drug resistance. With a widely distributed expression across different cell types, ABCG2 plays a central role in ATP-dependent efflux of a vast range of endogenous and exogenous molecules, thereby maintaining cellular homeostasis and providing tissue protection against xenobiotic insults. However, ABCG2 expression is subjected to alterations under various pathophysiological conditions such as inflammation, infection, tissue injury, disease pathology and in response to xenobiotics and endobiotics. These changes may interfere with the bioavailability of therapeutic substrate drugs conferring drug resistance and in certain cases worsen the pathophysiological state aggravating its severity. Considering the crucial role of ABCG2 in normal physiology, therapeutic interventions directly targeting the transporter function may produce serious side effects. Therefore, modulation of transporter regulation instead of inhibiting the transporter itself will allow subtle changes in ABCG2 activity. This requires a thorough comprehension of diverse factors and complex signaling pathways (Kinases, Wnt/β-catenin, Sonic hedgehog) operating at multiple regulatory levels dictating ABCG2 expression and activity. This review features a background on the physiological role of transporter, factors that modulate ABCG2 levels and highlights various signaling pathways, molecular mechanisms and genetic polymorphisms in ABCG2 regulation. This understanding will aid in identifying potential molecular targets for therapeutic interventions to overcome ABCG2-mediated multidrug resistance (MDR) and to manage ABCG2-related pathophysiology.

Identification of prognostic long intergenic non-coding RNAs as competing endogenous RNAs with KRAS mutations in colorectal cancer

Colorectal cancer (CRC) is recognized as a common type of human cancer, and KRAS mutations are correlated with poor CRC survival outcomes. The evaluation and prediction of CRC results remain challenging. In the present study, RNA sequencing and clinical data from The Cancer Genome Atlas were used to identify KRAS mutation-related prognostic long intergenic non-coding RNAs (lincRNAs) in CRC. Significantly dysregulated lincRNAs and independent prognostic lincRNAs with KRAS mutations in CRC were identified. Two lincRNAs with KRAS mutations, LINC00265 and AL390719.2, were selected as key prognostic lincRNAs for both 10- and 5-year survival rates. In addition, competing endogenous (ce)RNA models were constructed to comprehensively assess the oncogenic performance of the two key lincRNAs. The ceRNA models suggested that LINC00265 and AL390719.2 are critical for the cell cycle and cancer pathways. Finally, reverse transcription-quantitative PCR was used to validate the ceRNA models in 12 pairs of CRC tissue samples. These prognostic lincRNAs may provide novel biomarkers for the prognostic prediction of CRC. The ceRNA model may also demonstrate the underlying mechanism of these lincRNAs in CRC.

KDM4C contributes to cytarabine resistance in acute myeloid leukemia via regulating the miR-328-3p/CCND2 axis through MALAT1

Aims

Acute myeloid leukemia (AML) is an aggressive hematologic neoplasm, in which relapse due to drug resistance is the main cause for treatment failure and the disease progression. In this study, we aimed to investigate the molecular mechanism of KDM4C-dependent MALAT1/miR-328-3p/CCND2 axis in cytarabine (Ara-C) resistance in the context of AML.

Methods

Bioinformatics analysis was performed to predict the targeting relationships among KDM4C, MALAT1, miR-328-3p, and CCND2 in AML, which were validated with chromatin immunoprecipitation and dual-luciferase reporter assay. Methylation-specific polymerase chain reaction was conducted to detect the methylation of MALAT1 promoter. After conducting gain- and loss-of-function assays, we investigated the effect of KDM4C on cell Ara-C resistance. A NOD/SCID mouse model was established to further investigate the roles of KDM4C/MALAT1/miR-328-3p/CCND2 in Ara-C resistant AML cells.

Results

KDM4C expression was upregulated in AML. KDM4C upregulation promoted the demethylation in the promoter region of MALAT1 to increase its expression, MALAT1 targeted and inhibited miR-328-3p expression, enhancing the Ara-C resistance of HL-60/A. miR-328-3p targeted and suppressed the expression of CCND2 in HL-60/A to inhibit the Ara-C resistance. Mechanistically, KDM4C regulated miR-328-3p/CCND2 through MALAT1, resulting in Ara-C resistance in AML. Findings in an in vivo xenograft NOD/SCID mouse model further confirmed the contribution of KDM4C/MALAT1/miR-328-3p/CCND2 in the Ara-C resistant AML.

Conclusion

Our study demonstrated that KDM4C may up-regulate MALAT1 expression, which decreases the expression of miR-328-3p. The downregulation of miR-328-3p increased the level of CCND2, which induced the Ara-C resistance in AML.

microRNA-4429-5p suppresses the malignant development of colon cancer by targeting matrix metalloproteinase 16

Colon cancer has been recognized as the major reason for global cancer-associated mortality. microRNA (miRNA, miR)-4429-5p has been documented to act as a tumor-suppressive miRNA in some cancers, but its effect on colon cancer remains elusive. In this study, the biological effects of miR-4429-5p were investigated both in vitro by MTT, 5-ethynyl-2'-deoxyuridine (EdU), wound healing, and transwell assays and in vivo by a xenograft mice model. Western blot, quantitative reverse transcription-polymerase chain reaction (qRT-PCR), and dual-luciferase assay were used to identify the binding of miR-4429-5p on matrix metalloproteinase 16 (MMP16) 3'-UTR. Our results suggested that overexpression of miR-4429-5p hindered colon cancer cell proliferation, migration, and invasion, whereas knockdown of miR-4429-5p exhibited the opposite effect in colon cancer cells. Mechanistically, miR-4429-5p directly bound to the 3'-UTR of MMP16 and led to inhibition of MMP16 protein. Overexpression of miR-4429-5p inhibited colon tumor growth by targeting MMP16. Taken together, our study revealed that miR-4429-5p prevented colon cancer progression through targeting MMP16, indicating miR-4429-5p as a promising target for treatment improvement for colon cancer.

Elevated LOXL2 expression by LINC01347/miR-328-5p axis contributes to 5-FU chemotherapy resistance of colorectal cancer

Chemotherapy resistance after curative surgery is a major contributor to the mortality of colorectal cancer (CRC). Detailed mechanism studies of specific molecular alterations are critical to improving the available therapies for long-term disease administration. We explored the functional role of LINC01347 in chemotherapy resistance of CRC. Elevated LINC01347 expression was correlated with CRC disease progression during chemotherapy treatment. However, the functional role of LINC01347 and mechanism remained undefined. In this study, we demonstrated that elevated LINC01347 expression was correlated with late clinical stage and poor prognosis in CRC tumor tissues with TCGA data. Exogenous LINC01347 expression promoted cell proliferation and 5-FU resistance of CRC cells, while LINC01347 knockdown attenuated cell growth and 5-FU resistance in vitro and in vivo. Molecular analysis indicated that LINC01347 participated in the transcriptional regulation of LOXL2 by sponging miR-328-5p. LOXL2 knockdown impaired the LINC01347 overexpression induced 5-FU resistance in CRC cells. The clinical analysis supported miR-328-5p/LOXL2 as a candidate biomarker for chemotherapy resistance of CRC patients. Our study provided a molecular basis for the development of 5-FU based chemotherapy resistance in CRC by LINC01347/miR-328/LOXL2 axis. We identified LINC01347 as a prognostic biomarker and potential therapeutic target against 5-FU based chemotherapy resistance of CRC.

Cancer stem cells in colorectal cancer and the association with chemotherapy resistance

The incidence and mortality of colorectal cancer (CRC) have always been among the highest in the world, although the diagnosis and treatment are becoming more and more advanced. At present, the main reason is that patients have acquired drug resistance after long-term conventional drug treatment. An increasing number of evidences confirm the existence of cancer stem cells (CSCs), which are a group of special cells in cancer, only a small part of cancer cells. These special cell populations are not eliminated by chemotherapeutic drugs and result in tumor recurrence and metastasis after drug treatment. CSCs have the ability of self-renewal and multidirectional differentiation, which is associated with the occurrence and development of cancer. CSCs can be screened and identified by related surface markers. In this paper, the characteristic surface markers of CSCs in CRC and the related mechanism of drug resistance will be discussed in detail. A better understanding of the mechanism of CSCs resistance to chemotherapy may lead to better targeted therapy.

Identification of Host Factors Associated with the Development of Equine Herpesvirus Myeloencephalopathy by Transcriptomic Analysis of Peripheral Blood Mononuclear Cells from Horses

Equine herpesvirus-1 is the cause of respiratory disease, abortion, and equine herpesvirus myeloencephalopathy (EHM) in horses worldwide. EHM affects as many as 14% of infected horses and a cell-associated viremia is thought to be central for EHM pathogenesis. While EHM is infrequent in younger horses, up to 70% of aged horses develop EHM. The aging immune system likely contributes to EHM pathogenesis; however, little is known about the host factors associated with clinical EHM. Here, we used the “old mare model” to induce EHM following EHV-1 infection. Peripheral blood mononuclear cells (PBMCs) of horses prior to infection and during viremia were collected and RNA sequencing with differential gene expression was used to compare the transcriptome of horses that did (EHM group) and did not (non-EHM group) develop clinical EHM. Interestingly, horses exhibiting EHM did not show respiratory disease, while non-EHM horses showed significant respiratory disease starting on day 2 post infection. Multiple immune pathways differed in EHM horses in response to EHV-1. These included an upregulation of IL-6 gene expression, a dysregulation of T-cell activation through AP-1 and responses skewed towards a T-helper 2 phenotype. Further, a dysregulation of coagulation and an upregulation of elements in the progesterone response were observed in EHM horses.

MiRNA-mediated EMT and CSCs in cancer chemoresistance

Cancer stem cells (CSCs) are a small group of cancer cells, which contribute to tumorigenesis and cancer progression. Cancer cells undergoing epithelial-to-mesenchymal transition (EMT) acquire the chemoresistant ability, which is regarded as an important feature of CSCs. Thus, there emerges an opinion that the generation of CSCs is considered to be driven by EMT. In this complex process, microRNAs (miRNAs) are found to play a key role. In order to overcome the drug resistance, inhibiting EMT as well as CSCs phenotype seem feasible. Thereinto, regulating the EMT- or CSCs-associated miRNAs is a crucial approach. Herein, we conduct this review to elaborate on the complicated interplay between EMT and CSCs in cancer chemoresistance, which is modulated by miRNAs. In addition, we elucidate the therapeutic strategy to overcome drug resistance through targeting EMT and CSCs.

Informatics Inference of Exercise-Induced Modulation of Brain Pathways Based on Cerebrospinal Fluid Micro-RNAs in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Introduction: The post-exertional malaise of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) was modeled by comparing micro-RNA (miRNA) in cerebrospinal fluid from subjects who had no exercise versus submaximal exercise. Materials and Methods: Differentially expressed miRNAs were examined by informatics methods to predict potential targets and regulatory pathways affected by exercise. Results: miR-608, miR-328, miR-200a-5p, miR-93-3p, and miR-92a-3p had higher levels in subjects who rested overnight (nonexercise n=45) compared to subjects who had exercised before their lumbar punctures (n=15). The combination was examined in DIANA MiRpath v3.0, TarBase, Cytoscape, and Ingenuity software® to select the intersection of target mRNAs. DIANA found 33 targets that may be elevated after exercise, including TGFBR1, IGFR1, and CDC42. Adhesion and adherens junctions were the most frequent pathways. Ingenuity selected seven targets that had complementary mechanistic pathways involving GNAQ, ADCY3, RAP1B, and PIK3R3. Potential target cells expressing high levels of these genes included choroid plexus, neurons, and microglia. Conclusion: The reduction of this combination of miRNAs in cerebrospinal fluid after exercise suggested upregulation of phosphoinositol signaling pathways and altered adhesion during the post-exertional malaise of ME/CFS. Clinical Trial Registration Nos.: NCT01291758 and NCT00810225.

The Roles of Cancer Stem Cells and Therapy Resistance in Colorectal Carcinoma

Cancer stem cells (CSCs) are the main culprits involved in therapy resistance and disease recurrence in colorectal carcinoma (CRC). Results using cell culture, animal models and tissues from patients with CRC suggest the indispensable roles of colorectal CSCs in therapeutic failure. Conventional therapies target proliferating and mature cancer cells, while CSCs are mostly quiescent and poorly differentiated, thereby they can easily survive chemotherapeutic insults. The aberrant activation of Wnt/β-catenin, Notch, Hedgehog, Hippo/YAP (Yes-associated protein) and phosphatidylinositol 3-kinase/protein kinase B facilitates CSCs with excessive self-renewal and therapy resistance property in CRC. CSCs survive the chemo-radiotherapies by escaping therapy mediated DNA damage via altering the cell cycle checkpoints, increasing DNA damage repair capacity and by an efficient scavenging of reactive oxygen species. Furthermore, dysregulations of miRNAs e.g., miR-21, miR-93, miR-203, miR-215, miR-497 etc., modulate the therapeutic sensitivity of colorectal CSCs by regulating growth and survival signalling. In addition, a reversible quiescent G₀ state and the re-entering cell cycle capacity of colorectal CSCs can accelerate tumour regeneration after treatment. Moreover, switching to favourable metabolic signatures during a therapeutic regimen will add more complexity in therapeutic outcomes against CSCs. Therapeutic strategies targeting these underlying mechanisms of CSCs’ therapy resistance could provide a promising outcome, however, deep understanding and concerted research are necessary to design novel therapies targeting CSCs. To conclude, the understanding of these mechanisms of CSC in CRC could lead to the improved management of patients with CRC.

Right and left-sided colon cancers - specificity of molecular mechanisms in tumorigenesis and progression

Background

Given the differences in embryonic origin, vascular and nervous supplies, microbiotic burden, and main physiological functions of left and right colons, tumor location is increasingly suggested to dictate tumor behavior affecting pathology, progression and prognosis. Right-sided colon cancers arise in the cecum, ascending colon, hepatic flexure and/or transverse colon, while left-sided colon cancers arise in the splenic flexure, descending, and/or sigmoid colon. In contrast to prior reports, we attempt to delineate programs of tumorigenesis independently for each side.

Methods

Four hundred and eleven samples were extracted from The Cancer Genome Atlas-COAD cohort, based on a conservative sample inclusion criterion. Each side was independently analyzed with respect to their respective normal tissue, at the level of transcription, post-transcription, miRNA control and methylation in both a stage specific and stage-agnostic manner.

Results

Our results indicate a suppression of enzymes involved in various stages of carcinogen breakdown including CYP2C8, CYP4F12, GSTA1, and UGT1A within right colon tumors. This implies its reduced capacity to detoxify carcinogens, contributing to a genotoxic tumor environment, and subsequently a more aggressive phenotype. Additionally, we highlight a crucial nexus between calcium homeostasis (sensing, mobilization and absorption) and immune/GPCR signaling within left-sided tumors, possibly contributing to its reduced proliferative and metastatic potential. Interestingly, two genes SLC6A4 and HOXB13 show opposing regulatory trends within right and left tumors. Post-transcriptional regulation mediated by both RNA-binding proteins (e.g. NKRF (in left) and MSI2 (in right)) and miRNAs (e.g. miR-29a (in left); miR-155, miR181-d, miR-576 and miR23a (in right)) appear to exhibit side-specificity in control of their target transcripts and is pronounced in right colon tumors. Additionally, methylation results depict location-specific differences, with increased hypomethylation in open seas within left tumors, and increased hypermethylation of CpG islands within right tumors.

Conclusions

Differences in molecular mechanisms captured here highlight distinctions in tumorigenesis and progression between left and right colon tumors, which will serve as the basis for future studies, influencing the efficacies of existing and future diagnostic, prognostic and therapeutic interventions.

MiR-328-3p inhibits cell proliferation and metastasis in colorectal cancer by targeting Girdin and inhibiting the PI3K/Akt signaling pathway

MiR-328-3p has been reported to be downregulated and serve as a tumor suppressor in several cancers. Previous studies only have reported the downregulation of miR-328-3p in CRC. However, the roles of miR-328-3p in CRC growth and metastasis were unknown. In this study, we demonstrated that miR-328-3p overexpression inhibited cell proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT). The PI3K/Akt signaling pathway was also inactivated by miR-328-3p overexpression. MiR-328-3p knockdown showed the opposite effects. In addition, we confirmed that miR-328-3p directly bound to 3'UTR of Girdin and negatively regulated its expression. Girdin knockdown or treatment with PI3K inhibitor LY294002 blocked the effects of miR-328-3p inhibitor on cell proliferation, metastasis, and the PI3K/Akt signaling pathway. Moreover, pre-miR-328 decreased numbers of liver metastatic nodules, and reduced the levels of p-Akt, p-Girdin, and Girdin in metastatic tissues in liver. In conclusion, miR-328-3p may inhibit proliferation and metastasis of CRC cells by targeting Girdin and inactivating the PI3K/Akt signaling pathway. MiR-328-3p may be a novel target in cancer therapy.

Tea polyphenols and their chemopreventive and therapeutic effects on colorectal cancer

Colorectal cancer (CRC), a multifactorial disease, is usually induced and developed through complex mechanisms, including impact of diet and lifestyle, genomic abnormalities, change of signaling pathways, inflammatory response, oxidation stress, dysbiosis, and so on. As natural polyphenolic phytochemicals that exist primarily in tea, tea polyphenols (TPs) have been shown to have many clinical applications, especially as anticancer agents. Most animal studies and epidemiological studies have demonstrated that TPs can prevent and treat CRC. TPs can inhibit the growth and metastasis of CRC by exerting the anti-inflammatory, anti-oxidative or pro-oxidative, and pro-apoptotic effects, which are achieved by modulations at multiple levels. Many experiments have demonstrated that TPs can modulate several signaling pathways in cancer cells, including the mitogen-activated protein kinase pathway, phosphatidylinositol-3 kinase/Akt pathway, Wnt/β-catenin pathway, and 67 kDa laminin receptor pathway, to inhibit proliferation and promote cell apoptosis. In addition, novel studies have also suggested that TPs can prevent the growth and metastasis of CRC by modulating the composition of gut microbiota to improve immune system and decrease inflammatory responses. Molecular pathological epidemiology, a novel multidisciplinary investigation, has made great progress on CRC, and the further molecular pathological epidemiology research should be developed in the field of TPs and CRC. This review summarizes the existing in vitro and in vivo animal and human studies and potential mechanisms to examine the effects of tea polyphenols on CRC.

The integrative knowledge base for miRNA-mRNA expression in colorectal cancer

"miRNA colorectal cancer" (https://mirna-coadread.omics.si/) is a freely available web application for studying microRNA and mRNA expression and their correlation in colorectal cancer. To the best of our knowledge, "miRNA colorectal cancer" has the largest knowledge base of miRNA-target gene expressions and correlations in colorectal cancer, based on the largest available sample size from the same source of data. Data from high-throughput molecular profiling of 295 colon and rectum adenocarcinoma samples from The Cancer Genome Atlas was analyzed and integrated into our knowledge base. The objective of developing this web application was to help researchers to discover the behavior and role of miRNA-target gene interactions in colorectal cancer. For this purpose, results of differential expression and correlation analyses of miRNA and mRNA data collected in our knowledge base are available through web forms. To validate our knowledge base experimentally, we selected genes FN1, TGFB2, RND3, ZEB1 and ZEB2 and miRNAs hsa-miR-200a/b/c-3p, hsa-miR-141-3p and hsa-miR-429. Both approaches revealed a negative correlation between miRNA hsa-miR-200b/c-3p and its target gene FN1 and between hsa-miR-200a-3p and its target TGFB2, thus supporting the usefulness of the developed knowledge base.

Circular RNA-Associated Competing Endogenous RNA Network and Prognostic Nomogram for Patients With Colorectal Cancer

Background: Genetic characteristics remain underutilized for establishing prognostic models for colorectal cancer (CRC). We explored the underlying regulatory mechanisms of circular RNAs (circRNAs) that act as competing endogenous RNAs (ceRNAs) and constructed a gene-based nomogram to predict overall survival (OS) in patients with CRC.

Methods: We obtained circRNA expression profiling data from the Gene Expression Omnibus (GEO) database. MicroRNA (miRNA) and mRNA expression profiles, with associated clinical data, were obtained from The Cancer Genome Atlas (TCGA). A ceRNA network was established using Cytoscape. Interactions between differential genes were analyzed, and hub genes were identified using the cytoHubba application. The R package “clusterProfiler” was used to evaluate the Gene Ontology (GO) annotations of the differentially expressed mRNAs and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. Database-extracted patients were randomized into a training and validation cohorts. A prognostic model was developed using the training set based on multivariate Cox analyses and was then assessed in the validation set. The accuracy of the model was evaluated using discrimination and calibration plots.

Results: Thirteen circRNAs, 62 miRNAs, and 301 mRNAs were used to construct the ceRNA network; 10 hub genes were identified via the PPI network. Next, a circRNA- miRNA hub of gene-regulatory modules was established based on four differentially expressed circRNAs, eight differentially expressed miRNAs, and nine differentially expressed mRNAs (DEmRNAs). GO and KEGG pathway analyses indicated the possible association of DEmRNAs with CRC onset and progression. Multivariate analyses revealed that age, tumor stage, and CXCR5 expression were independent risk factors for OS. A CXCR5-based model was developed to predict the OS of patients with CRC in our training set. Our nomogram showed relatively good accuracy, with C-indices of 0.757 and 0.702 in the training and validation sets, respectively. The areas under the curve of the nomograms predicting 3- and 5-years OS were 0.749 and 0.805 in the training set and 0.706 and 0.779 in the validation set, respectively.

Conclusions: Our data suggested that the hsa_circ_00001666/has-mir-1229/CXCR5 axis plays an important role in the pathogenesis of CRC, thereby identifying a potential therapeutic target. The proposed CXCR5-based nomogram may also assist surgeons in devising personalized treatments for patients with this disease.

Roles of microRNAs as non-invasive biomarker and therapeutic target in colorectal cancer

MicroRNAs are endogenous, short non-coding RNA molecules that function as critical regulators of various biological processes. There is a strong functional evidence linking the involvement of dysregulated miRNAs to the occurrence, development and progression of colorectal cancer. Studies indicate that while overexpression of oncomiRs, and repression of tumor suppressor miRNAs tends to drive the overall tumorigenic process, the global picture of aberrant miRNA expression in colorectal cancer can classify the disease into multiple molecular phenotypes. Moreover, the expression pattern of miRNAs in colorectal cancer make them viable disease determinants as well as potential therapeutic targets. Through this review, we will summarize the importance of miRNAs in the etiology and progression of colorectal cancer. Specifically, we will explore the key role played by these RNA molecules as likely therapeutic avenues and the strategies presently available to target them. Finally, we will investigate the role of miRNAs as potential non-invasive diagnostic and prognostic biomarkers in colorectal cancer.

Study on miRNAs in Pan-Cancer of the Digestive Tract Based on the Illumina HiSeq System Data Sequencing

Objective

miRNA has gained attention as a therapeutic target in various malignancies. The proposal of this study was to investigate the biological functions of key miRNAs and target genes in cancers of the digestive tract which include esophageal carcinoma (ESCA), gastric adenocarcinoma (GAC), colon adenocarcinoma (COAD), and rectal adenocarcinoma (READ).

Materials and Methods

After screening differentially expressed miRNAs (DEMIs) and differentially expressed mRNAs (DEMs) in four digestive cancers from The Cancer Genome Atlas (TCGA) database, the diagnostic value of above DEMIs was evaluated by receiver-operating characteristic (ROC) curve analysis. Then, corresponding DEMIs' target genes were predicted by miRWalk 2.0. Intersection of predicted target genes and DEMs was taken as the target genes of DEMIs, and miRNA-mRNA regulatory networks between DEMIs and target genes were constructed. Meanwhile, the univariate Cox risk regression model was used to screen miRNAs with distinct prognostic value, and Kaplan-Meier analysis was used to determine their significance of prognosis. Furthermore, we performed bioinformatics methods including protein-protein interaction (PPI) networks, gene ontology (GO) annotation, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis, and gene group RIDA analysis by Gene-Cloud of Biotechnology Information (GCBI) to explore the function and molecular mechanisms of DEMIs and predicted target genes in tumor development.

Results

Eventually, 3 DEMIs (miR-7-3, miR-328, and miR-323a) with significant prognostic value were obtained. In addition, 3 DEMIs (miR-490-3p, miR-133a-3p, and miR-552-3p) and 281 target genes were identified, and the 3 DEMIs showed high diagnostic value in READ and moderate diagnostic value in ESCA, GAC, and COAD. Also, the miRNA-mRNA regulatory network with 3 DEMIs and 281 overlapping genes was successfully established. Functional enrichment analysis showed that 281 overlapping genes were mainly related to regulation of cell proliferation, cell migration, and PI3K-Akt signaling pathway.

Conclusion

The diagnostic value and prognostic value of significant DEMIs in cancers of the digestive tract were identified, which may provide a novel direction for treatment and prognosis improvement of cancers of the digestive tract.

MicroRNAs Affect Complement Regulator Expression and Mitochondrial Activity to Modulate Cell Resistance to Complement-Dependent Cytotoxicity

MicroRNAs (miR) are small RNA molecules that shape the cell transcriptome and proteome through regulation of mRNA stability and translation. Here, we examined their function as determinants of cell resistance to complement-dependent cytotoxicity (CDC). To achieve this goal, we compared the expression of microRNAs between complement-resistant and -sensitive K562 leukemia, Raji lymphoma, and HCT-116 colorectal carcinoma cells. Global microRNA array analysis identified miR-150, miR-328, and miR-616 as regulators of CDC resistance. Inhibition of miR-150 reduced resistance, whereas inhibition of miR-328 or miR-616 enhanced cell resistance. Treatment of K562 cells with a sublytic dose of complement was shown to rapidly increase miR-150, miR-328, and miR-616 expression. Protein targets of these microRNAs were analyzed in K562 cells by mass spectrometry-based proteomics. Expression of the complement membrane regulatory proteins CD46 and CD59 was significantly enhanced after inhibition of miR-328 and miR-616. Enrichment of proteins of mitochondria, known target organelles in CDC, was observed after miR-150, miR-328, and miR-616 inhibition. In conclusion, miR-150, miR-328, and miR-616 regulate cell resistance to CDC by modifying the expression of the membrane complement regulators CD46 and CD59 and the response of the mitochondria to complement lytic attack. These microRNAs may be considered targets for intervention in complement-associated diseases and in anticancer, complement-based therapy.

GREM2 maintains stem cell-like phenotypes in gastric cancer cells by regulating the JNK signaling pathway

Gastric cancer (GC) is one of the major malignancies worldwide. This study was conducted to explore the mechanism by which GREM2 maintains biological properties of GC stem cells (GCSCs), and proved that GREM2 could potentially regulate the proliferation, apoptosis, invasion, migration and tumorigenic ability of GCSCs through the regulation of the JNK signaling pathway. In silico analysis was utilized to retrieve expression microarray related to GC, and differential analysis was conducted. The cell line with the highest GREM2 expression was overexpressed with GREM2 mimic, silencing GREM2 by siRNA, or treated with activator or inhibitor of the JNK signaling pathway. Subsequently, expression of GREM2, JNK signaling pathway-, apoptosis- or migration and invasion-associated factors were determined. Proliferation, migration, invasion, apoptosis of GCSCs in vitro and tumorigenic ability and lymph node metastasis of GCSCs in vivo were determined. Based on the in silico analysis of GSE49051, GREM2 was determined to be overexpressed in GC and its expression was the highest in the MKN-45 cell line, which was selected for the subsequent experiments. Silencing of GREM2 or inhibition of the JNK signaling pathway suppressed the proliferation, migration and invasion, while promoting apoptosis of GCSCs in vitro as well as inhibiting tumorigenesis and lymph node metastasis in vivo. In conclusion, the aforementioned findings suggest that the silencing of GREM2 suppresses the activation of the JNK signaling pathway, thereby inhibiting tumor progression. Therefore, GREM2-mediated JNK signaling pathway was expected to be a new therapeutic strategy for GC.

MicroRNAs as potential therapeutic targets to predict responses to oxaliplatin in colorectal cancer: From basic evidence to therapeutic implication

Colorectal cancer (CRC) is one of the most common malignancies with poor prognosis. Oxaliplatin-based chemotherapy is an important treatment for CRC; however, the cells develop resistance to therapy. The mechanisms underlying oxaliplatin resistance are complex and unclear. There is increasing evidence that microRNAs (miRNAs) (i.e., miR-34a, miR-143, miR-153, miR-27a, miR-218, and miR-520) play an essential role in tumorigenesis and chemotherapy resistance, by targeting various cellular and molecular pathways (i.e., PI3K/Akt/Wnt, EMT, p53, p21, and ATM) that are involved in the pathogenesis of CRC. Identifying the miRNAs that are involved in chemo-resistance, and their function, may help as a potential therapeutic option for treatment of CRC or as potential prognostic biomarker. Here, we summarized the clinical impact of miRNAs that have critical roles in the development of resistance to oxaliplatin in CRC.

Hypoxia- and MicroRNA-Induced Metabolic Reprogramming of Tumor-Initiating Cells

Colorectal cancer (CRC), the second most common cause of cancer mortality in the Western world, is a highly heterogeneous disease that is driven by a rare subpopulation of tumorigenic cells, known as cancer stem cells (CSCs) or tumor-initiating cells (TICs). Over the past few years, a plethora of different approaches, aimed at identifying and eradicating these self-renewing TICs, have been described. A focus on the metabolic and bioenergetic differences between TICs and less aggressive differentiated cancer cells has thereby emerged as a promising strategy to specifically target the tumorigenic cell compartment. Extrinsic factors, such as nutrient availability or tumor hypoxia, are known to influence the metabolic state of TICs. In this review, we aim to summarize the current knowledge on environmental stress factors and how they affect the metabolism of TICs, with a special focus on microRNA (miRNA)- and hypoxia-induced effects on colon TICs.

Inhibition of miR-328-3p Impairs Cancer Stem Cell Function and Prevents Metastasis in Ovarian Cancer

Cancer stem cells (CSC) play a central role in cancer metastasis and development of drug resistance. miRNA are important in regulating CSC properties and are considered potential therapeutic targets. Here we report that miR-328-3p (miR-328) is significantly upregulated in ovarian CSC. High expression of miR-328 maintained CSC properties by directly targeting DNA damage binding protein 2, which has been shown previously to inhibit ovarian CSC. Reduced activity of ERK signaling in ovarian CSC, mainly due to a low level of reactive oxygen species, contributed to the enhanced expression of miR-328 and maintenance of CSC. Inhibition of miR-328 in mouse orthotopic ovarian xenografts impeded tumor growth and prevented tumor metastasis. In summary, our findings provide a novel mechanism underlying maintenance of the CSC population in ovarian cancer and suggest that targeted inhibition of miR-328 could be exploited for the eradication of CSC and aversion of tumor metastasis in ovarian cancer. SIGNIFICANCE: These findings present inhibition of miR-328 as a novel strategy for efficient elimination of CSC to prevent tumor metastasis and recurrence in patients with epithelial ovarian cancer.

Elevated expression of microRNA-328-3p suppresses aggressive malignant behaviors via targeting matrix metalloprotease 16 in osteosarcoma

Background

A previous study indicated that microRNA(miR)-328-3p upregulation might be critical for resveratrol-mediated suppression of metastatic ability in human osteosarcoma, implying its potential role in this malignancy. However, the clinical significance and the biological functions of miR-328-3p in osteosarcoma remain unclear.

Methods

miR-328-3p expression in 88 pairs of osteosarcoma and matched non-cancerous bone tissues were detected by quantitative real-time PCR. Then, the associations of miR-328-3p expression with various clinicopathological features of osteosarcoma patients were statistically analyzed. Cell Counting Kit-8 and scratch-wound healing were performed to evaluate roles of miR-328-3p in human osteosarcoma cells. After that, luciferase reporter assay, western blot analysis and rescue assay were applied to determine the underlying molecular mechanisms of miR-328-3p in osteosarcoma cells.

Results

miR-328-3p expression in osteosarcoma tissues was significantly lower than those in non-cancerous bone tissues (P<0.001). miR-328-3p downregulation was significantly associated with advanced surgical stage, positive metastasis and recurrence (all P<0.05). Functionally, enforced expression of miR-328-3p efficiently suppressed cell proliferation and migration in vitro. Moreover, matrix metalloprotease 16 (MMP16) was identified as a direct target of miR-328-3p in osteosarcoma cells. Notably, MMP16 overexpression partially reversed the miR-328-3p-inhibited cell proliferation and migration of osteosarcoma cells.

Conclusions

Our data indicated that the aberrant expression of miR-328-3p may play a crucial role in malignant progression of human osteosarcoma. More importantly, miR-328-3p may function as a tumor suppressor inhibiting osteosarcoma cell proliferation and migration partially mediated by regulating of MMP16.

Targeting cancer stem cells as therapeutic approach in the treatment of colorectal cancer

Colorectal cancer is one of the most common cancers globally. A large portion of colorectal cancer patients who are treated with conventional chemotherapy eventually develop local recurrence or metastases. The failure of a complete cure in colorectal cancer patients may be related to the lack of complete eradication of cancer stem cells when using conventional therapy. Colorectal cancer stem cells comprise a small population of tumor cells that possess the properties of rapid proliferation and differentiation. The colorectal cancer stem cells are also phenotypically and molecularly distinct, and resistant to conventional chemo-radiotherapy. Therefore, it is important to identify approaches in combination with conventional therapy for targeting and eradicating cancer cells. The aim of this review was to summarize the main findings of recent studies on targeting colorectal cancer stem cells as a novel therapeutic approach in colorectal cancer treatment.

The therapeutic role of inhibition of miR-328 on pulmonary carcinoma induced by chlamydia pneumoniae through targeting histone H2AX

Lung cancer represents a major healthy concern due to high incidence and morality. Increasing evidences showed critical regulatory role of microRNA (miR) in cell growth, differentiation and apoptosis. It has been indicated that the level of miR-328 is abnormally up regulated in lung cancer cell line, which is correlated with cell apoptosis. An in vitro lung cancer model was established through induction of chlamydia pneumonia. Western blot and real-time quantitative PCR were used to measure miR-328 level and its effects on histone H2AX expression. Bioinformatics analysis and luciferase reporter gene assay were to determine if H2AX was the direct target of miR-328. TUNEL assay, AV-PI staining and Caspase-3 activity assay measured the effect of the decrease of miR-328 on lung cancer cell apoptosis at both in vivo and in vitro level. Bioinformatics analysis predicted histone H2AX as the target of miR-328 during the regulation of lung cancer. Both in vivo and in vitro knockdown of miR-328 up-regulated H2AX expression and elevated TUNEL-positive cell number. In vivo down-regulation of miR-328 decreased incidence of lung cancer induced by chlamydia pneumoniae, suppressed tumor volume, increased caspase 3 activity, and facilitated tumor cell apoptosis. Histone protein H2AX serves as the target of miR-328 and participates in lung cancer regulation. Suppression of miR-328 level promotes lung cancer tissue apoptosis, which provides novel target for lung cancer therapy.

MicroRNA: A new player in response to therapy for colorectal cancer

Colorectal cancer (CRC) is one of the important malignancies that result in cancer-related deaths worldwide. Multiple lines of evidence have indicated that different responses to therapy in CRC cells led to the failure of the current therapies. Hence, identification of the underlying cellular and molecular pathways involved in the emergence of different responses from CRC cells could contribute to finding and designing new therapeutic platforms to overcome the present limitations. Among the various targets involved in CRC pathogenesis, microRNAs (miRNAs) have key roles in many signaling pathways that are associated with the initiation and progression of CRC. Increasing evidence has confirmed that miRNAs as epigenetic regulators could play critical roles in the response (resistance or sensitivity) to therapy. Cancer stem cells are well-known players in resistance to therapy in CRC. They have been shown to play significant roles via inhibition and activation of many miRNA networks. Hence, miRNAs could be involved in the resistance and sensitivity of therapy in CRC cells via affecting different mechanisms, such as activation of cancer stem cells. Here, we summarized the role of various miRNAs in response to therapy of CRC cells. Moreover, we highlighted the roles of these molecules in the function of cancer stem cells, which are known as important players in the resistance to therapy in CRC.

Serum-based microRNA signature predicts relapse and therapeutic outcome of adjuvant chemotherapy in colorectal cancer patients

Background

Approximately 60% of patients with colorectal cancer (CRC) undergo either local recurrence or distant metastases after surgery. Current prognostic biomarkers are insufficient to predict recurrence of CRC and provide little forecast information about what patients are likely to receive benefit from the adjuvant chemotherapy. As microRNAs (miRNAs) constantly exist in human serum and being used to predict the prognosis of a various cancers, this study was designed to identify miRNA-based circulating biomarkers to predict clinical outcomes of CRC.

Methods

A serum-focused miRNA expression was used to investigate if miRNA expression profiles could predict the clinical outcomes of patients with CRC. We created miRNA signature profiles associated in the training set (n = 40), and further validated its prediction in two independent testing cohorts.

Results

Using Cox regression and risk-score analysis, we identified a four-miRNA signature (miR-652-3p, miR-342-3p, miR-501-3p and miR-328-3p) for the prediction of tumor relapse and the overall survival(OS) of patients with CRC in the training set (n = 40). This miRNA signature was further validated in a testing set (n = 226) and another independent cohort (n = 56). A high-risk signature score was significantly associated with CRC tumor recurrence and poor treatment outcome. Multivariable Cox regression models indicated that the risk score, based on the four-miRNA signature, was an independent prognostic classifier for patients with CRC.

Conclusions

The serum miRNA signature may serve as a minimally invasive predictor for tumor relapse and treatment outcome in patients with CRC and provide a useful reference for treatment selection.

Current understanding and clinical utility of miRNAs regulation of colon cancer stem cells

Cancer stem cells (CSCs) in colorectal tumorigenesis are suggested to be responsible for initiation, development and propagation of colorectal cancer (CRC) and have been extensively characterized by the expression of phenotypic determinants, such as surface or intracellular proteins. The generation of CSCs is likely due to a dysregulation of the signaling pathways that principally control self-renewal and pluripotency in normal intestinal stem cells (ISCs) through different (epi)genetic changes that define cell fate, identity, and phenotype of CSCs. These aspects are currently under intense investigation. In the framework of the oncogenic signaling pathways controlled by microRNAs (miRNAs) during CRC development, a plethora of data suggests that miRNAs can play a key role in several regulatory pathways involving CSCs biology, epithelial-mesenchymal transition (EMT), angiogenesis, metastatization, and pharmacoresistance. This review examines the most relevant evidences about the role of miRNAs in the etiology of CRC, through the regulation of colon CSCs and the principal differences between colorectal CSCs and benign stem cells. In this perspective, the utility of the principal CSCs-related miRNAs changes is explored, emphasizing their use as potential biomarkers to aid in diagnosis, prognosis and predicting response to therapy in CRC patients, but also as promising targets for more effective and personalized anti-CRC treatments.

Dual targeting delivery of miR-328 by functionalized mesoporous silica nanoparticles for colorectal cancer therapy

Aim: We aim to explore the regulatory mechanism of miR-328 and further develop miR-328-loaded mesoporous silica nanoparticles (MSNs) and surface-decorated with polymerized dopamine, epithelial cell adhesion molecule aptamer and bevacizumab for the dual-targeting treatment of colorectal cancer (CRC). Materials & methods: The relationship between miR-328 and CPTP and the mechanism and antitumor effect of MSNs-miR-328@PDA-PEG-Apt-Bev were evaluated. Results: We found CPTP is a direct target of miR-328. Compared with other groups, MSNs-miR-328@PDA-PEG-Apt-Bev can significantly increase the level of miR-328 and inhibit the expression of CPTP in SW480 cells. The results exhibit this multifunctional bioconjugates can achieve an increased binding ability and much higher cytotoxicity to CRC both in vitro and in vivo. Conclusion: This multifunctional nanoplatform is a promising miRNA replacement therapy for CRC.

Multiregion whole-exome sequencing of matched primary and metastatic tumors revealed genomic heterogeneity and suggested polyclonal seeding in colorectal cancer metastasis

Background

Distant metastasis accounts for 90% of deaths from colorectal cancer (CRC). Genomic heterogeneity has been reported in various solid malignancies, but remains largely under-explored in metastatic CRC tumors, especially in primary to metastatic tumor evolution.

Patients and methods

We conducted high-depth whole-exome sequencing in multiple regions of matched primary and metastatic CRC tumors. Using a total of 28 tumor, normal, and lymph node tissues, we analyzed inter- and intra-individual heterogeneity, inferred the tumor subclonal architectures, and depicted the subclonal evolutionary routes from primary to metastatic tumors.

Results

CRC has significant inter-individual but relatively limited intra-individual heterogeneity. Genomic landscapes were more similar within primary, metastatic, or lymph node tumors than across these types. Metastatic tumors exhibited less intratumor heterogeneity than primary tumors, indicating that single-region sequencing may be adequate to identify important metastasis mutations to guide treatment. Remarkably, all metastatic tumors inherited multiple genetically distinct subclones from primary tumors, supporting a possible polyclonal seeding mechanism for metastasis. Analysis of one patient with the trio samples of primary, metastatic, and lymph node tumors supported a mechanism of synchronous parallel dissemination from the primary to metastatic tumors that was not mediated through lymph nodes.

Conclusions

In CRC, metastatic tumors have different but less heterogeneous genomic landscapes than primary tumors. It is possible that CRC metastasis is, at least partly, mediated through a polyclonal seeding mechanism. These findings demonstrated the rationale and feasibility for identifying and targeting primary tumor-derived metastasis-potent subclones for the prediction, prevention, and treatment of CRC metastasis.

miR-328 mediates a metabolic shift in colon cancer cells by targeting SLC2A1/GLUT1

Purpose

Increasing evidence shows that altered metabolism is a critical hallmark in colon cancer. There is a strong need to explore the molecular mechanisms underlying cancer metabolism. Whether the aberrant expression of microRNAs contributes to cancer metabolism is not fully understood. miR-328 is a putative potential target of SLC2A1, but the regulating mechanism between them remains unknown. We have examined whether miR-328 directly regulates SLC2A1/GLUT1 expression in colon cancer cells.

Methods

We performed in silico bioinformatic analyses to identify miR-328-mediated molecular pathways and targets. We also performed luciferase assays and western blot analyses in LOVO and SW480 colon cancer cell lines. In addition, we assessed miR-328 expression in 47 paired tumor and normal tissue specimens from resected colon cancer patients.

Results

Luciferase reporter assays showed that miR-328 directly targeted SLC2A1 3′-untranslated region (UTR), with a significant decrease in luciferase activity in both LOVO and SW480 cell lines. These results were validated by western blot. miR-328 expression was significantly downregulated in tumor tissue compared with paired normal tissue.

Conclusions

Our results show that miR-328 targets SLC2A1/GLUT1. We suggest that miR-328 may be involved in the orchestration of the Warburg effect in colon cancer cells. Furthermore, miR‐328 expression is reduced in colon cancer patients and thus inversely correlates with the classically reported upregulated SLC2A1/GLUT1 expression in tumors.

Oxaliplatin resistance in colorectal cancer cells is mediated via activation of ABCG2 to alleviate ER stress induced apoptosis

Oxaliplatin (OXA), is a third generation platinum drug used as first-line chemotherapy in colorectal cancer (CRC). Cancer cells acquires resistance to anti-cancer drug and develops resistance. ATP-binding cassette (ABC) drug transporter ABCG2, one of multidrug resistance (MDR) protein which can effectively discharge a wide spectrum of chemotherapeutic agents out of cancer cells and subsequently reduce the intracellular concentration of these drugs. Role of ABCG2 and plausible molecular signaling pathways involved in Oxaliplatin-Resistant (OXA-R) colon cancer cells was evaluated in the present study. OXA resistant LoVo cells was developed by exposing the colon cells to OXA in a dose-dependent manner. Development of multi drug resistance in OXA-R cells was confirmed by exposing the resistance cells to oxaliplatin, 5-FU, and doxorubicin. OXA treatment resulted in G2 phase arrest in parental LoVo cells, which was overcome by OXA-R LoVo cells. mRNA and protein expression of ABCG2 and phosphorylation of NF-κB was significantly higher in OXA-R than parental cells. Levels of ER stress markers were downregulated in OXA-R than parental cells. OXA-R LoVo cells exposed to NF-κB inhibitor QNZ effectively reduced the ABCG2 and p-NF-κB expression and increased ER stress marker expression. On other hand, invasion and migratory effect of OXA-R cells were found to be decreased, when compared to parental cells. Metastasis marker proteins also downregulated in OXA-R cells. ABCG2 inhibitor verapamil, downregulate ABCG2, induce ER stress markers and induces apoptosis. In vivo studies in nude mice also confirms the same.

MicroRNAs in the etiology of colorectal cancer: pathways and clinical implications

MicroRNAs (miRNAs) are small single-stranded RNAs that repress mRNA translation and trigger mRNA degradation. Of the ∼1900 miRNA-encoding genes present in the human genome, ∼250 miRNAs are reported to have changes in abundance or altered functions in colorectal cancer. Thousands of studies have documented aberrant miRNA levels in colorectal cancer, with some miRNAs reported to actively regulate tumorigenesis. A recurrent phenomenon with miRNAs is their frequent participation in feedback loops, which probably serve to reinforce or magnify biological outcomes to manifest a particular cellular phenotype. Here, we review the roles of oncogenic miRNAs (oncomiRs), tumor suppressive miRNAs (anti-oncomiRs) and miRNA regulators in colorectal cancer. Given their stability in patient-derived samples and ease of detection with standard and novel techniques, we also discuss the potential use of miRNAs as biomarkers in the diagnosis of colorectal cancer and as prognostic indicators of this disease. MiRNAs also represent attractive candidates for targeted therapies because their function can be manipulated through the use of synthetic antagonists and miRNA mimics.

Summary: This Review provides an overview of some important microRNAs and their roles in colorectal cancer.

Circulating microRNAs as potential biomarkers to detect transformation of Barrett's oesophagus to oesophageal adenocarcinoma

Objective

Circulating microRNAs (miRNAs) are promising biomarkers for the early detection of cancers. This study aimed to address potential circulating miRNAs to monitor the progression from Barrett’s oesophagus (BO) to oesophageal adenocarcinoma (OAC).

Design

We comprehensively analysed tissue and serum miRNA expression profiles of BO mice model (L2-interleukin-1β (IL-1β) mice) using microarray analysis. To validate the data from mice, a published dataset of human plasma miRNAs, consisting of eight patients with OAC, eight with BO and six healthy controls, was used (GSE51410).

Results

We identified 20 upregulated miRNAs and 44 downregulated miRNAs both in tissues and in sera of 46-week-old mice compared with 28-week-old mice. Two of the 20 miRNAs (miR-128-3 p and miR-328-3 p) were upregulated, and five of the 44 miRNAs (miR-143-3 p, miR-144-3 p, miR-15a-5p, miR-1-3 p and miR-133b) were downregulated in plasma of patients with OAC compared with plasma of patients with BO. Receiver operating characteristic curve analysis revealed that a prediction index calculated by the above-mentioned seven miRNAs could discriminate between patients with OAC and those without OAC with the area under the curve of 0.91, sensitivity of 1 and specificity of 0.75.

Conclusions

Levels of the seven circulating miRNAs may represent the tissue miRNA levels and could be promising non-invasive biomarkers to evaluate the carcinogenic process of BO.

MicroRNAs are important regulators of drug resistance in colorectal cancer

Despite of continuous development of cancer treatment over the past decades, drug resistance is still one of the major hurdles of effective therapy for advanced colorectal cancer (CRC) worldwide and the understanding of its underlying mechanisms remains limited. Data which have emerged suggests that many microRNAs (miRNAs) may contribute to drug resistance in CRC. Major findings on miRNA functions in drug resistance of CRC are systemically reviewed here, with the goal of providing new updates to broaden our comprehension of its mechanisms and evidence to utilize miRNAs as potential therapeutic targets for CRC treatment.

Regulatory miRNAs in Colorectal Carcinogenesis and Metastasis

Colorectal cancer is one of the most common malignancies and is the second-leading cause of cancer-related death world-wide, which is linked to genetic mutations, epigenetic alterations, and oncogenic signaling activation. MicroRNAs, one of the categories of epigenetics, have been demonstrated significant roles in carcinogenesis and progression through regulating of oncogenic signaling pathways, stem cells, epithelial-mesenchymal transition, and metastasis. This review summarizes the roles of microRNAs in the regulating of Wnt, Ras, TGF-β, and inflammatory signaling pathways, stemness, and epithelial-mesenchymal transition, for carcinogenesis and metastasis in colorectal cancer. Improving our understanding of the mechanisms of regulatory interactions of microRNAs with signaling pathways in colorectal cancer formation and progression will aid in determining the genes responsible for colorectal cancer initiation, progression, metastasis, and recurrence and, finally, in developing personalized approaches for cancer prevention and therapy.

High expression of matrix metalloproteinases 16 is associated with the aggressive malignant behavior and poor survival outcome in colorectal carcinoma

Recent evidence suggested an important role of matrix metalloproteinases 16 (MMP16) in the progression of several cancers. However, the contribution of MMP16 to colorectal cancer (CRC) remains elusive. In this study, we combined analyzed the MMP16 expression in The Cancer Genome Atlas (TCGA), GSE39582 database and in-house database. In TCGA and GSE39584 database, the log-rank test demonstrated that overall survival (OS) for patients with low MMP16 expression in tumor tissues was significantly higher than those with high expression (P < 0.05). In the validation cohort, high MMP16 expression was significantly correlated with N stage (P = 0.008) and lymphovascular invasion (P = 0.002). The 5-year OS and disease free survival (DFS) in high and low MMP16 expression groups were 66.0% and 80.6%, 54.3% and 72.8%, respectively. Univariate and multivariate analysis showed that high MMP16 expression was an independently prognosis factor for both OS and DFS (P < 0.05). Functional study found that silencing MMP16 expression could inhibit migration and invasion of colon cancer cells. In conclusion, high expression of MMP16 is associated with the aggressive malignant behavior and poor survival outcome of CRC patients. MMP16 can serve as an indicator of prognosis as well as a potential novel target for treatment of CRC patients.

Membrane-type matrix metalloproteases as diverse effectors of cancer progression

Membrane-type matrix metalloproteases (MT-MMP) are pivotal regulators of cell invasion, growth and survival. Tethered to the cell membranes by a transmembrane domain or GPI-anchor, the six MT-MMPs can exert these functions via cell surface-associated extracellular matrix degradation or proteolytic protein processing, including shedding or release of signaling receptors, adhesion molecules, growth factors and other pericellular proteins. By interactions with signaling scaffold or cytoskeleton, the C-terminal cytoplasmic tail of the transmembrane MT-MMPs further extends their functionality to signaling or structural relay. MT-MMPs are differentially expressed in cancer. The most extensively studied MMP14/MT1-MMP is induced in various cancers along malignant transformation via pathways activated by mutations in tumor suppressors or proto-oncogenes and changes in tumor microenvironment including cellular heterogeneity, extracellular matrix composition, tissue oxygenation, and inflammation. Classically such induction involves transcriptional programs related to epithelial-to-mesenchymal transition. Besides inhibition by endogenous tissue inhibitors, MT-MMP activities are spatially and timely regulated at multiple levels by microtubular vesicular trafficking, dimerization/oligomerization, other interactions and localization in the actin-based invadosomes, in both tumor and the stroma. The functions of MT-MMPs are multifaceted within reciprocal cellular responses in the evolving tumor microenvironment, which poses the importance of these proteases beyond the central function as matrix scissors, and necessitates us to rethink MT-MMPs as dynamic signaling proteases of cancer. This article is part of a Special Issue entitled: Matrix Metalloproteinases edited by Rafael Fridman.

Tumor-Initiating Cells: a criTICal review of isolation approaches and new challenges in targeting strategies

Most cancers contain a subpopulation of highly tumorigenic cells, known as cancer stem cells (CSCs) or tumor-initiating cells (TICs). Targeting TICs may be essential to achieve cure, because of their self-renewal and tumorigenic properties as well as their resistance to conventional therapies. Despite significant advances in TIC biology, their isolation and identification remain largely disputed and incompletely established. In this review, we discuss the latest developments in isolation and culturing approaches of TICs, with focus on colorectal cancer (CRC). We feature recent findings on TIC-relevant signaling pathways and the metabolic identity of TICs, as well as their current clinical implications. Lastly, we highlight the influence of inter- and intra-tumoral heterogeneity on TIC function and targeting approaches.

Regulation of miRNAs by herbal medicine: An emerging field in cancer therapies

MicroRNAs' expression profiles have recently gained major attention as far as cancer research is concerned. MicroRNAs are able to inhibit target gene expression via binding to the 3' UTR of target mRNA, resulting in target mRNA cleavage or translation inhibition. MicroRNAs play significant parts in a myriad of biological processes; studies have proven, on the other hand, that aberrant microRNA expression is, more often than not, associated with the growth and progression of cancers. MicroRNAs could act as oncogenes (oncomir) or tumor suppressors and can also be utilized as biomarkers for diagnosis, prognosis, and cancer therapy. Recent studies have shown that such herbal extracts as Shikonin, Sinomenium acutum, curcumin, Olea europaea, ginseng, and Coptidis Rhizoma could alter microRNA expression profiles through inhibiting cancer cell development, activating the apoptosis pathway, or increasing the efficacy of conventional cancer therapeutics. Such findings patently suggest that the novel specific targeting of microRNAs by herbal extracts could complete the restriction of tumors by killing the cancerous cells so as to recover survival results in patients diagnosed with malignancies. In this review, we summarized the current research about microRNA biogenesis, microRNAs in cancer, herbal compounds with anti-cancer effects and novel strategies for employing herbal extracts in order to target microRNAs for a better treatment of patients diagnosed with cancer.

Glioblastoma: exosome and microRNA as novel diagnosis biomarkers

Glioblastoma (GBM) is known as a tumor type, which arises from astrocytes. Several studies indicated that GBM tumor cells are malignant. This is because of the fact that they consist of different cell types, which are reproducing very quickly and are also supported by a large network of blood vessels. The correct identification of various stages of GBM could help to better treat the patients with this disease. Therefore, new biomarkers such as exosomes and microRNAs (miRNAs) may help us to learn more about GBM and they may also lead to a more effective treatment for patients with GBM. Exosomes have emerged as biological vehicles, which can perform various tasks in carcinogenesis pathways such as PI3K/AKT, SOX2, PTEN, ERK, and STAT3. The miRNAs are known as small noncoding RNAs that are involved in several GBM pathogenic events. These molecules have key roles in various biological processes such as angiogenesis, metastasis and tumor growth. In this study, we highlighted various exosomes and miRNAs that could be used for diagnosis and/or prognosis biomarkers in patients with GBM.

MiRNAs and miRNA Polymorphisms Modify Drug Response

Differences in expression of drug response-related genes contribute to inter-individual variation in drugs’ biological effects. MicroRNAs (miRNAs) are small noncoding RNAs emerging as new players in epigenetic regulation of gene expression at post-transcriptional level. MiRNAs regulate the expression of genes involved in drug metabolism, drug transportation, drug targets and downstream signal molecules directly or indirectly. MiRNA polymorphisms, the genetic variations affecting miRNA expression and/or miRNA-mRNA interaction, provide a new insight into the understanding of inter-individual difference in drug response. Here, we provide an overview of the recent progress in miRNAs mediated regulation of biotransformation enzymes, drug transporters, and nuclear receptors. We also describe the implications of miRNA polymorphisms in cancer chemotherapy response.

Up- regulation of miR-328-3p sensitizes non-small cell lung cancer to radiotherapy

MicroRNAs (miRNAs) are believed to be resistant against radiotherapy in certain types of cancers. The aim of our study was to determine the clinical application of miRNAs in non-small cell lung cancer (NSCLC). Sixty NSCLC tissue samples and adjacent histologically normal tissues were obtained for miRNAs microarray analysis and validated by RT-qPCR. Correlation between miRNA expression level and clinicopathological features was evaluated. Our study examined the influence of changed miRNA expression on the damaged DNA and its associated radio sensitivity. Luciferase assay was performed to determine potential effects on the targeted gene. Our study identified fifteen altered miRNAs in which miR-328-3p was down regulated in NSCLC tumour tissue as compared to normal tissues. Down-expression of miR-328-3p was positively associated with an enhanced lymph node metastasis, advanced clinical stage and a shortened survival rate. miR-328-3p expression was decreased in A549 cells compared to other NSCLC cell lines. Up-regulation of miR-328-3p demonstrated a survival inhibition effect in A549 and restored NSCLC cells' sensitivity to radio therapy. An increased miR-328-3p expression promoted irradiation-induced DNA damage in cells. γ-H2AX was identified as the direct target of miR-328-3p. Over-expressed miR-328-3p can improve the radiosensitvity of cells by altering the DNA damage/repair signalling pathways in NSCLC.