The role of microRNAs in colorectal cancer

MicroRNA-Assisted Hormone Cell Signaling in Colorectal Cancer Resistance

Despite substantial progress in cancer therapy, colorectal cancer (CRC) is still the third leading cause of cancer death worldwide, mainly due to the acquisition of resistance and disease recurrence in patients. Growing evidence indicates that deregulation of hormone signaling pathways and their cross-talk with other signaling cascades inside CRC cells may have an impact on therapy resistance. MicroRNAs (miRNAs) are small conserved non-coding RNAs thatfunction as negative regulators in many gene expression processes. Key studies have identified miRNA alterations in cancer progression and drug resistance. In this review, we provide a comprehensive overview and assessment of miRNAs role in hormone signaling pathways in CRC drug resistance and their potential as future targets for overcoming resistance to treatment.

Differential Expression of miR-20a and miR-145 in Colorectal Tumors as Potential Location-specific miRNAs

BACKGROUND

MicroRNAs (miRNAs), as tissue specific regulators of gene transcription, may be served as biomarkers for Colorectal Cancer (CRC).

OBJECTIVE

This study aimed to investigate the potential role of the cancer-related hsa-miRNAs as biomarkers in Colon Cancer (CC) and Rectal Cancer (RC).

METHODS

A total of 148 CRC samples (74 rectum and 74 colon) and 74 adjacent normal tissues were collected to examine the differential expression of selected ten hsa-miRNAs using quantitative Reverse Transcriptase PCR (qRT-PCR).

RESULTS

The significantly elevated levels of miR-21, miR-133b, miR-18a, miR-20a, and miR-135b, and decreased levels of miR-34a, miR-200c, miR-145, and let-7g were detected in colorectal tumors compared to the healthy tissues (P<0.05). Hsa-miR-20a was significantly overexpressed in rectum compared to colon (p =0.028) from a cut-off value of 3.15 with a sensitivity of 66% and a specificity of 60% and an AUC value of 0.962. Also, hsa-miR-145 was significantly overexpressed in colon compared to the rectum (p =0.02) from a cut-off value of 3.9 with a sensitivity of 55% and a specificity of 61% and an AUC value of 0.91.

CONCLUSION

In conclusion, hsa-miR-20a and hsa-miR-145, as potential tissue-specific biomarkers for distinguishing RC and CC, improve realizing the molecular differences between these local tumors.

Prognostic value of BRAF/MIR-17 signature and B-Raf protein expression in patients with colorectal cancer: A pilot study

Background

Despite the recent improvement in colorectal cancer (CRC) treatment, it still has a poor prognosis with a low survival rate. Genetic and epigenetic mechanisms have proved to play a substantial role in CRC tumorigenesis and progression. According to Gene Ontology and TargetScan analyses, the B‐Raf proto‐oncogene (BRAF) gene is one of the microRNA‐17 (miR‐17) targets. We aimed to explore the prognostic value of B‐Raf protein and BRAF/microRNA‐17 (MIR‐17) gene expression signature in CRC archived samples.

Methods

B‐Raf protein expression was identified by immunohistochemistry, while gene expression studies were quantified by real‐time qPCR in 53 paired archived CRC specimens.

Results

The BRAF showed higher expressions in CRC specimens relative to non‐cancer tissues (p = 0.006). MIR17 expression was inversely and significantly correlated with both B‐Raf protein (r = −0.79, p < 0.001) and gene expression (r = −0.35, p = 0.010) and showed a significant direct correlation with a high rate of relapse (p = 0.020). BRAF/miR‐17 expression in CRC was associated inversely with tumor size, high grade of colonic carcinoma, lymph node metastasis, and carcinoma subtype. Spearman correlation and Kaplan‐Meier survival curve analyses revealed that disease‐free survival and overall survival were inversely and significantly correlated with positive B‐Raf protein expression (r = −0.31 and −0.35, p = 0.023 and 0.011, respectively) and directly correlated with log BRAF/MIR17 ratio (r = 0.50 and 0.41, p < 0.001 and = 0.003, respectively). Cox hazard regression analysis revealed the BRAF/MIR17 ratio could predict both types of patients' survival, among other variables.

Conclusion

BRAF/MIR17 ratio could have prognostic utility in patients with CRC. Further larger‐scale studies are warranted to confirm this utility.

MicroRNA, Diabetes Mellitus and Colorectal Cancer

Diabetes mellitus (DM) is an endocrinological disorder that is due to either the pancreas not producing enough insulin, or the body does not respond appropriately to insulin. There are many complications of DM such as retinopathy, nephropathy, and peripheral neuropathy. In addition to these complications, DM was reported to be associated with different cancers. In this review, we discuss the association between DM and colorectal cancer (CRC). CRC is the third most commonly diagnosed cancer worldwide that mostly affects older people, however, its incidence and mortality are rising among young people. We discuss the relationship between DM and CRC based on their common microRNA (miRNA) biomarkers. miRNAs are non-coding RNAs playing important functions in cell differentiation, development, regulation of cell cycle, and apoptosis. miRNAs can inhibit cell proliferation and induce apoptosis in CRC cells. miRNAs also can improve glucose tolerance and insulin sensitivity. Therefore, investigating the common miRNA biomarkers of both DM and CRC can shed a light on how these two diseases are correlated and more understanding of the link between these two diseases can help the prevention of both DM and CRC.

Pyknon-Containing Transcripts Are Downregulated in Colorectal Cancer Tumors, and Loss of PYK44 Is Associated With Worse Patient Outcome

Pyknons are specific human/primate-specific DNA motifs at least 16 nucleotides long that are repeated in blocks in intergenic and intronic regions of the genome and can be located in a new class of non-coding RNAs of variable length. Recent studies reported that pyknon deregulation could be involved in the carcinogenesis process, including colorectal cancer. We evaluated the expression profile of a set of 12 pyknons in a set of molecularly characterized colorectal cancer (CRC) patients. The pyknons (PYK10, PYK14, PYK17, PYK26, PYK27, PYK40, PYK41, PYK42, PYK43, PYK44, PYK83, and PYK90) expression was determined by qRT-PCR. A pilot analysis of 20 cases was performed, and consistent results were obtained for PYK10, PYK17, PYK42, PYK44, and PYK83. Further, the expression of the selected pyknons was evaluated in 73 CRC cases. Moreover, in 52 patients, we compared the expression profile in both tumor and normal tissues. All five pyknons analyzed showed significantly lower expression levels in the tumor compared to normal tissue. It was observed an association between expression of PYK10 with TP53 mutations (p = 0.029), PYK17 to histologic grade (p = 0.035), and PYK44 to clinical staging (p = 0.016). Moreover, levels of PYK44 were significantly associated with the patient's poor overall survival (p = 0.04). We reported the significant downregulation of pyknons motifs in tumor tissue compared with the normal counterpart, and the association of lower PYK44 expression with worse patient outcome. Further studies are needed to extend and validate these findings and determine the clinical-pathological impact.

Prognostic Factors Involved in the Epithelial-Mesenchymal Transition Process in Colorectal Cancer Have a Preponderant Role in Oxidative Stress: A Systematic Review and Meta-Analysis

Epithelial-to-mesenchymal transition (EMT) is one of the most accepted mechanisms leading to metastasis, which is responsible for most of the cancer-related deaths. In order to identify EMT-related biomarkers able to predict clinical outcomes in colorectal cancer (CRC), a systematic review and meta-analysis of prognostic factors associated to overall survival (OS) and progression free survival (PFS) was conducted. The systematic literature search included studies from June 2014 to June 2019 available at PubMed and Scopus databases. Meta-analysis was performed for those markers appearing in minimum three works with a total number of 8656 participants. The rest were enlisted and subjected to functional enrichment. We identified nine clinical biomarkers and 73 EMT-related molecular biomarkers associated to OS and/or PFS in CRC. The significant enrichment of biomarkers found involved in cellular oxidoreductase activity suggests that ROS generation plays an active role in the EMT process. Clinical practice needs new biomarkers with a reliable prognostic value able to predict clinical outcomes in CRC. Our integrative work supports the role of oxidative stress in tumorigenesis and EMT progress highlighting the importance of deciphering this specific mechanism to get a better understanding of metastasis.

Hyaluronic acid-decorated liposomal nanoparticles for targeted delivery of 5-fluorouracil into HT-29 colorectal cancer cells

The use of liposomes as drug carriers improves the therapeutic efficacy of anticancer drugs, while at the same time reducing side effects. Hyaluronic acid (HA) is recognized by the CD44 receptor, which is overexpressed in many cancer cells. In this study, we developed HA-modified liposomes encapsulating 5-fluorouracil (5-FU) and tested them against a CD44 expressing colorectal cell line (HT29) and a non-CD44 expressing hepatoma cell line. The average size of 5-FU-lipo and 5-FU-lipo-HA nanoparticles were 112 ± 28 and 144 ± 77 nm, respectively. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) assay showed selective cancer cell death depending on the CD44 expression in a time-dependent manner. Apoptosis assays and cell-cycle analysis indicated that G0/G1 arrest occurred. The colony formation study revealed that cells treated with 5-FU-lipo and 5-FU-lipo-HA had reduced colony formation. Quantitative reverse-transcription polymerase chain reaction study showed that the oncogenic messenger RNA and microRNA levels were significantly reduced in the 5-FU-lipo-HA-treated group, while tumor suppressors were increased in that group. We suggest that optimal targeted delivery and release of 5-FU into colorectal cancer cells, renders them susceptible to apoptosis, cell-cycle arrest, and decreased colony formation.

The P53/microRNA network: A potential tumor suppressor with a role in anticancer therapy

MicroRNAs (miRNAs) are endogenous and small non-coding RNAs that have been identified as mediators of tumor suppression as well as stress responses mediated by p53 suppressors. MiRNAs may act as tumor suppressors under certain conditions. MiRNAs regulated by p53 may control the expression of processes such as cell cycle progression, cell survival, and angiogenesis. P53 activity and expression are also controlled by miRNA; consequently alterations in the p53-miRNA network may be essential for tumor initiation and progression. Future studies on the p53-miRNA network presumably would find it helpful in diagnostic and therapeutic approaches or as tools for various cancers.

Genomic and molecular alterations associated with early-onset and adolescent and young adult colorectal cancer

While the incidence of colorectal cancer (CRC) in the US has declined at a pace of 3% annually between 2003 and 2012, there has been an increase in the incidence of early-onset colorectal cancer (EOCRC). The reasons for this increase are unclear. Diet, the environment, the microbiome and alcohol consumption have all been proposed as contributing factors. There is the possibility that EOCRC has a unique biology. Overlapping with the EOCRC age range is CRC in adolescent and young adults (AYA) that share many molecular characteristics with EOCRC. The purpose of this review is to cover current progress in our understanding of the biology of CRC in the context of adolescent and young adult CRC and EOCRC and discuss future directions.

Identification of MiR-211-5p as a tumor suppressor by targeting ACSL4 in Hepatocellular Carcinoma

BACKGROUND

Liver cancer is among the most common malignancy worldwide. Hepatocellular carcinoma (HCC), the principal histological subtype of liver cancer, is globally the third most common cause of cancer-related mortality. The high rates of recurrence and metastasis contribute to the poor prognosis of HCC patients. In recent years, increasing evidence has shown that microRNAs (miRNAs) are involved in the tumorigenesis, progression, and prognosis of HCC.

METHODS

To screen for key candidate miRNAs in HCC, three microarray datasets were downloaded from Gene Expression Omnibus (GEO). The sole common differentially expressed miRNA (DEmiR) observed in the above three datasets using a Venn diagram was microRNA-211-5p (miR-211-5p). The expression of miR-211-5p from HCC tissues was measured in several HCC cell lines. Additionally, using Kaplan-Meier plots, the potential prognostic value of miR-211-5p in HCC was analyzed. Cell counting kit-8 (CCK-8) and transwell assays examined the ability of miR-211-5p to induce cell proliferation, migration, and invasion in HCC cultures. The interaction of miR-211-5p and Acyl-CoA Synthetase Long Chain Family Member 4 (ACSL4) was assessed both theoretically and using a luciferase reporter assay. Finally, the ability of miR-211-5p to modulate tumorigenesis in HCC in vivo was assessed after establishing a xenograft model.

RESULTS

qRT-PCR demonstrated that the relative expression of miR-211-5p was considerably down-regulated in HCC tissues and cell lines compared with normal tissue. Kaplan-Meier plots indicated that HCC patients with decreased expression of miR-211-5p had poor overall survival. Upregulation of miR-211-5p in vitro consistently suppressed cell proliferation, migration, and invasion. In contrast, enhanced expression of ACSL4 promoted a malignant phenotype in HCC cells. Importantly, we discovered that ACSL4 was a direct downstream target of miR-211-5p in HCC, and that miR-211-5p suppressed the malignant phenotype by inhibition of ACSL4 expression. Furthermore, miR-211-5p overexpression impaired tumorigenesis and growth of HCC in vivo.

CONCLUSIONS

Targeting miR-211-5p and the downstream gene ACSL4 will possibly provide novel insight and represents a promising approach to future therapy of HCC patients.

MicroRNA-421 Inhibits Apoptosis by Downregulating Caspase-3 in Human Colorectal Cancer

Purpose

Dysregulated microRNAs (miRNAs/miRs) have been reported to play significant roles in pathogenesis of colorectal cancer (CRC). Previous studies have demonstrated that miR-421 regulates apoptosis in some cancers. Caspase-3 plays a key role in apoptosis, but the relationship between miR-421 and caspase-3 in CRC has not been determined. In this study, we investigated the role of miR-421 in CRC and the relationship between miR-421 and caspase-3.

Methods

Expression of miR-421 and caspase-3 were detected in human paired CRC cancer tissues and corresponding paracancerous tissues. In situ detection of tissue, apoptosis was performed via the TUNEL assay. HCT116 and SW480 cell lines were subjected to several in vitro experiments to explore the relationship between miRNA421 and caspase-3 during apoptosis using miR421 mimics/antagomir and luciferase reporter assay. Apoptosis was measured by determining the levels and activity of caspase-3 as well as DNA fragmentation. Luciferase reporter assay was performed to determine the potential interaction of miR-421 with caspase-3.

Results

The results showed that the expression of miR-421 in cancer tissues was higher than that in corresponding paracancerous tissues. Inhibition of miR-421 induced apoptosis, as shown by the upregulation of caspase-3 activity and expression as well as DNA fragmentation, which were attenuated by miR-421 mimic. We further showed that miR-421 targeted and inhibited CASP3 expression by targeting sites located in the 3ʹ-untranslated region (3ʹ-UTR) of CASP3 mRNA.

Conclusion

This study demonstrated an anti-apoptotic role of miR-421 in CRC and identified caspase-3 gene as a direct target of miR-421. These findings provide a potential treatment strategy using miR-421 as a therapeutic target for CRC.

miR-144 suppresses cell proliferation and migration in colorectal cancer by targeting NRAS

Colorectal cancer (CRC) is a type of malignant cancer that has become particularly prevalent worldwide. It is of crucial importance to CRC treatment that the underlying molecular mechanism of CRC progression is determined. The NRAS gene is an important small G protein that is involved in various biological processes, including cancers. NRAS is an oncogene in many neoplasms but its function and regulation in CRC have seldom been investigated. In this study, it was uncovered that the NRAS protein was significantly upregulated in CRC tissues. According to a bioinformatics prediction, we identified that miR-144 may target NRAS to suppress its expression. In vitro experiments indicated that miR-144 decreased NRAS expression in different CRC cell lines (SW480, LoVo, and Caco2). By inhibiting NRAS, miR-144 repress SW480 cell proliferation and migration. Moreover, miR-144 decelerated the growth of SW480 xenograft tumors in vivo by targeting NRAS. In summary, our results identified a novel miR-144-NRAS axis in CRC that could promote the research and treatment of CRC.

MicroRNAs and Apoptosis in Colorectal Cancer

Colorectal cancer (CRC) is the third leading cause of cancer death in the world, and its incidence is rising in developing countries. Treatment with 5-Fluorouracil (5-FU) is known to improve survival in CRC patients. Most anti-cancer therapies trigger apoptosis induction to eliminate malignant cells. However, de-regulated apoptotic signaling allows cancer cells to escape this signaling, leading to therapeutic resistance. Treatment resistance is a major challenge in the development of effective therapies. The microRNAs (miRNAs) play important roles in CRC treatment resistance and CRC progression and apoptosis. This review discusses the role of miRNAs in contributing to the promotion or inhibition of apoptosis in CRC and the role of miRNAs in modulating treatment resistance in CRC cells.

KRAS-associated microRNAs in colorectal cancer

Colorectal cancer (CRC) is one of the leading causes of cancerrelated death worldwide. Despite progress in treatment of cancers, CRC with KRAS mutations are resistant towards anti-EGFR treatment. MicroRNAs have been discovered in an exponential manner within the last few years and have been known to exert either an onco-miRNA or tumor suppressive effect. Here, the various roles of microRNAs involved in the initiation and progression of KRAS-regulated CRC are summarized. A thorough understanding of the roles and functions of the plethora of microRNAs associated with KRAS in CRC will grant insights into the provision of other potential therapeutic targets as well as treatment. MicroRNAs may also serve as potential molecular classifier or early detection biomarkers for future treatment and diagnosis of CRC.

Long Non-Coding RNA CRNDE Promotes Colorectal Carcinoma Cell Progression and Paclitaxel Resistance by Regulating miR-126-5p/ATAD2 Axis

Background

Long non-coding RNA colorectal neoplasia differentially expressed (lncRNA CRNDE) and microRNA-126-5p (miR-126-5p) were reported to be related to the development of colorectal carcinoma (CRC). However, the detailed mechanism of CRNDE and miR-126-5p is not fully understood. The purpose of this research was to explore their roles and molecular mechanism in CRC.

Methods

Quantitative real-time polymerase chain reaction was performed to detect the transcription levels of genes. Paclitaxel (PTX) was used to analyze cell drug resistance. 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay and flow cytometry analysis were employed to assess cell proliferation and apoptosis, respectively. Furthermore, cell migratory and invasive abilities were measured using transwell assay. The interaction between miR-126-5p and CRNDE or ATPase family AAA domain-containing protein 2 (ATAD2) was predicted by online tool starbase and then confirmed using the dual-luciferase reporter assay. Besides, Western blot assay was carried out to detect the levels of proteins.

Results

CRNDE and ATAD2 expressions were upregulated and miR-126-5p expression was downregulated in CRC tissues and cells. CRNDE depletion repressed PTX resistance and the growth of CRC cells. Interestingly, we found that miR-126-5p was a target gene of CRNDE, and miR-126-5p directly targeted ATAD2. Furthermore, CRNDE affected CRC cell progression via modulation of miR-126-5p/ATAD2 axis in CRC cells.

Conclusion

Our data suggested that CRNDE regulated CRC cell development and PTX resistance by modulating miR-126-5p/ATAD2 axis, providing the theoretical basis for the treatment of CRC patients.

Identification of microRNAs and their Endonucleolytic Cleavaged target mRNAs in colorectal cancer

Background

Colorectal cancer (CRC) ranks the third among the most common malignancies globally. It is well known that microRNAs (miRNAs) play vital roles in destabilizing mRNAs and repressing their translations in this disease. However, the mechanism of miRNA-induced mRNA cleavage remains to be investigated.

Method

In this study, high-throughput small RNA (sRNA) sequencing was utilized to identify and profile miRNAs from six pairs of colorectal cancer tissues (CTs) and adjacent tissues (CNs). Degradome sequencing (DS) was employed to detect the cleaved target genes. The Database for Annotation, Visualization and Integrated Discovery (DAVID) software was used for GO (Gene Ontology) and KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway analysis.

Results

In total, 1278 known miRNAs (clustered into 337 families) and 131 novel miRNAs were characterized in the CT and CN libraries, respectively. Of those, 420 known and eight novel miRNAs were defined as differentially expressed miRNAs (DEmiRNAs) by comparing the expression levels observed in the CT and CN libraries. Furthermore, through DS, 9685 and 202 potential target transcripts were characterized as target genes for 268 known and 33 novel miRNAs, respectively. It was further predicted that a total of 264 targeted genes for the 85 DEmiRNAs are involved in proteoglycans in cancer and the AMP-activated protein kinase signaling pathway. After systemic analysis of prognosis-related miRNA targets in those cancer-related signal pathways, we found that two targets ezrin (EZR) and hematopoietic cell-specific Lyn substrate 1 (HCLS1) had the potential prognostic characteristics with CRC regarding over survival (OS) or recurrence.

Conclusion

In total, we found that endonucleolytic miRNA-directed mRNA cleavage occurs in CRC. A number of potential genes targeted by CRC-related miRNAs were identified and some may have the potential as prognosis markers of CRC. The present findings may lead to an improved better appreciation of the novel interaction mode between miRNAs and target genes in CRC.

Identification and Validation of MicroRNA Profiles in Fecal Samples for Detection of Colorectal Cancer

BACKGROUND & AIMS

Screening for colorectal cancer (CRC) is effective in the population at average risk. The most extended strategy in organized programs involves the fecal immunochemical test, which is limited by low sensitivity for the detection of advanced adenomas (AAs). We aimed to identify microRNA (miRNA) signatures in fecal samples that identify patients with AAs or CRC and might be used in noninvasive screening.

METHODS

Our study comprised 4 stages. In the discovery phase, we performed genome-wide miRNA expression profiling of 124 fresh, paired colorectal tumor and nontumor samples (30 CRC; 32 AAs) from patients in Spain. In the technical validation stage, miRNAs with altered expression levels in tumor vs nontumor tissues were quantified by reverse-transcription polymerase chain reaction in fecal samples from a subset of patients included in the discovery phase (n = 39) and individuals without colorectal neoplasms (controls, n = 39). In the clinical validation stage, the miRNAs found to be most significantly up-regulated by quantitative reverse transcription polymerase chain reaction analysis were measured in an independent set of fecal samples (n = 767) from patients with positive results from fecal immunochemical tests in a CRC screening program. Finally, we developed a model to identify patients with advanced neoplasms (CRCs or AAs) based on their miRNA profiles, using findings from colonoscopy as the reference standard.

RESULTS

Among 200 and 324 miRNAs significantly deregulated in CRC and AA tissues, respectively, 7 and 5 of these miRNAs were also found to be deregulated in feces (technical validation). Of them, MIR421, MIR130b-3p, and MIR27a-3p were confirmed to be upregulated in fecal samples from patients with advanced neoplasms. In our model, the combination of fecal level of MIR421, MIR27a-3p, and hemoglobin identified patients with CRC with an area under the curve (AUC) of 0.93, compared with an AUC of 0.67 for fecal hemoglobin concentration alone.

CONCLUSIONS

We found that increased levels of 2 miRNAs and hemoglobin in feces can identify patients with AAs or CRC more accurately than fecal hemoglobin concentration alone. Assays for these miRNAs might be added to fecal tests for the detection of CRC or AAs.

Associations Between miRNAs and Two Different Cancers: Breast and Colon

Objective

Screening approaches using microRNAs (miRNAs) have been gaining increased attention owing to their potential applications in the diagnosis, prognosis, and monitoring of cancer, because aberrant miRNA expression plays a role in the development and advancement of malignancies. The objectives of this study were to characterize mir21, miR31, mir143, mir145, and control RNU43, which are differentially expressed in peripheral blood mononuclear cells (PBMCs) of breast and colorectal cancer patients, compared to that in controls and to establish whether this is specific to breast and colon cancer for use as tumor markers.

Methods

Thirty newly diagnosed patients with breast cancer and 30 patients with colorectal cancer were enrolled together with 30 healthy controls. PBMCs were isolated from venous blood samples of individuals. Next, miRNA expression analysis was performed by a two-step method of reverse transcription and qPCR.

Results

The expression levels of miR-143 and miR-31 were significantly decreased, whereas the expression levels of miR-145 and miR-21 were significantly increased in breast cancer patients compared to those in healthy subjects. Moreover, the expression levels of miR-143, miR-145, and miR-21 were significantly increased and, in contrast, the changes in the expression levels of miR-31 were not statistically significant in colon cancer compared to those in healthy subjects. miR-21 exhibited the highest increase in both breast and colon cancers. There was a weak positive correlation between miR-145 and CA-15.3 in patients with breast cancer (r = 0.451; p = 0.012). miR-143 was positively correlated with the TNM stage in colon cancer patients (r = 0.568; p = 0.001).

Conclusion

A biomarker panel composed of miR-21, miR-31, miR-143, and miR-145 in PBMC may provide a new diagnostic approach for the early detection of breast and colon cancer. As miR-21 expression was found to be the highest among all the miRNAs evaluated, it may represent a new tumor biomarker and a candidate therapeutic drug or gene target in colon and breast cancer.

Novel MicroRNA Biomarkers for Colorectal Cancer Early Diagnosis and 5-Fluorouracil Chemotherapy Resistance but Not Prognosis: A Study from Databases to AI-Assisted Verifications

Colorectal cancer (CRC) is one of the major causes of cancer death worldwide. In general, early diagnosis for CRC and individual therapy have led to better survival for the cancer patients. Accumulating studies concerning biomarkers have provided positive evidence to improve cancer early diagnosis and better therapy. It is, however, still necessary to further investigate the precise biomarkers for cancer early diagnosis and precision therapy and predicting prognosis. In this study, AI-assisted systems with bioinformatics algorithm integrated with microarray and RNA sequencing (RNA-seq) gene expression (GE) data has been approached to predict microRNA (miRNA) biomarkers for early diagnosis of CRC based on the miRNA-messenger RNA (mRNA) interaction network. The relationships between the predicted miRNA biomarkers and other biological components were further analyzed on biological networks. Bayesian meta-analysis of diagnostic test was utilized to verify the diagnostic value of the miRNA candidate biomarkers and the combined multiple biomarkers. Biological function analysis was performed to detect the relationship of candidate miRNA biomarkers and identified biomarkers in pathways. Text mining was used to analyze the relationships of predicted miRNAs and their target genes with 5-fluorouracil (5-FU). Survival analyses were conducted to evaluate the prognostic values of these miRNAs in CRC. According to the number of miRNAs single regulated mRNAs (NSR) and the number of their regulated transcription factor gene percentage (TFP) on the miRNA-mRNA network, there were 12 promising miRNA biomarkers were selected. There were five potential candidate miRNAs (miRNA-186-5p, miRNA-10b-5, miRNA-30e-5p, miRNA-21 and miRNA-30e) were confirmed as CRC diagnostic biomarkers, and two of them (miRNA-21 and miRNA-30e) were previously reported. Furthermore, the combinations of the five candidate miRNAs biomarkers showed better prediction accuracy for CRC early diagnosis than the single miRNA biomarkers. miRNA-10b-5p and miRNA-30e-5p were associated with the 5-FU therapy resistance by targeting the related genes. These miRNAs biomarkers were not statistically associated with CRC prognosis.

Small RNA Profiling of piRNAs in Colorectal Cancer Identifies Consistent Overexpression of piR-24000 That Correlates Clinically with an Aggressive Disease Phenotype

Piwi-interacting RNAs (piRNAs) represent a novel class of small non-coding RNAs (ncRNAs) that have been shown to have a deregulated expression in several cancers, although their clinical significance in colorectal cancer (CRC) remains unclear. With an aim of delineating the piRNA distribution in CRC, we conducted a systematic discovery and validation of piRNAs within two clinical cohorts. In the discovery phase, we profiled tumor and adjacent normal tissues from 18 CRC patients by deep sequencing and identified a global piRNA downregulation in CRC. Moreover, we identified piR-24000 as an unexplored piRNA that was significantly overexpressed in CRC. Using qPCR, we validated the overexpression of piR-24000 in 87 CRC patients. Additionally, we identified a significant association between a high expression of piR-24000 and an aggressive CRC phenotype including poor differentiation, presence of distant metastases, and a higher stage. Lastly, ROC analysis demonstrated a strong diagnostic power of piR-24000 in discriminating CRC patients from normal subjects. Taken together, this study provides one of the earliest large-scale reports of the global distribution of piRNAs in CRC. In addition, piR-24000 was identified as a likely oncogene in CRC that can serve as a biomarker or a therapeutic target.

Targeted Nano-Drug Delivery of Colchicine against Colon Cancer Cells by Means of Mesoporous Silica Nanoparticles

Antimitotics are important anticancer agents and include the natural alkaloid prodrug colchicine (COL). However, a major challenge of using COL as an anticancer drug is its cytotoxicity. We developed a novel drug delivery system (DDS) for COL using mesoporous silica nanoparticles (MSNs). The MSNs were functionalized with phosphonate groups, loaded with COL, and coated with folic acid chitosan-glycine complex. The resulting nanoformulation, called MSNsPCOL/CG-FA, was tested for action against cancer and normal cell lines. The anticancer effect was highly enhanced for MSNsPCOL/CG-FA compared to COL. In the case of HCT116 cells, 100% inhibition was achieved. The efficiency of MSNsPCOL/CG-FA ranked in this order: HCT116 (colon cancer) > HepG2 (liver cancer) > PC3 (prostate cancer). MSNsPCOL/CG-FA exhibited low cytotoxicity (4%) compared to COL (~60%) in BJ1 normal cells. The mechanism of action was studied in detail for HCT116 cells and found to be primarily intrinsic apoptosis caused by an enhanced antimitotic effect. Furthermore, a contribution of genetic regulation (metastasis-associated lung adenocarcinoma transcript 1 (MALAT 1), and microRNA (mir-205)) and immunotherapy effects (angiopoietin-2 (Ang-2 protein) and programmed cell death protein 1 (PD-1) was found. Therefore, this study shows enhanced anticancer effects and reduced cytotoxicity of COL with targeted delivery compared to free COL and is a novel method of developing cancer immunotherapy using a low-cost small-molecule natural prodrug.

A network view of microRNA and gene interactions in different pathological stages of colon cancer

BACKGROUND

Colon cancer is one of the common cancers in human. Although the number of annual cases has decreased drastically, prognostic screening and translational methods can be improved. Hence, it is critical to understand the molecular mechanisms of disease progression and prognosis.

RESULTS

In this study, we develop a new strategy for integrating microRNA and gene expression profiles together with clinical information toward understanding the regulation of colon cancer. Particularly, we use this approach to identify microRNA and gene expression networks that are specific to certain pathological stages. To demonstrate the application of our method, we apply this approach to identify microRNA and gene interactions that are specific to pathological stages of colon cancer in The Cancer Genome Atlas (TCGA) datasets.

CONCLUSIONS

Our results show that there are significant differences in network connections between miRNAs and genes in different pathological stages of colon cancer. These findings point to a hypothesis that these networks signify different roles of microRNA and gene regulation in the pathogenesis and tumorigenesis of colon cancer.

circCCT3 Modulates Vascular Endothelial Growth Factor A and Wnt Signaling to Enhance Colorectal Cancer Metastasis Through Sponging miR-613

Colorectal cancer (CRC) has been suggested to be one of the leading cancer types all over the world. Till now, the molecular mechanism by which circCCT3 regulates CRC remains to be clarified. To detect mRNA and protein levels of various genes, Reverse Transcription-quantitative PCR and western blot were used in our study. Luciferase reporter assay was utilized to probe direct interaction between genes. We used transwell assay to assess the invasion ability of CRC cells. For apoptosis detection, immunofluorescence of CRC cells by Annexin V staining was performed. We carried out bioinformatic analysis to show higher expression of circCCT3 in human clinical CRC tumors. Low level of circCCT3 was closely associated with higher disease-free survival of CRC patients. Moreover, we found that circCCT3 was linked to advanced stage of CRC. miR-613 is the target of circCCT3 and responsible for circCCT3-modulated invasion and apoptosis of CRC cells. In addition, we identified WNT3 and vascular endothelial growth factor A (VEGFA) as downstream effectors of miR-613 in CRC cells. WNT3 and VEGFA overexpression resulted in partial rescue of miR-613-mediated phenotypes of CRC cells. In conclusion, we propose that circCCT3 contributes to CRC metastasis via miR-613/WNT3 or miR-613/VEGFA, promoting the development of therapeutical approaches for treating CRC.

Serum miR-663 expression and the diagnostic value in colorectal cancer

Colorectal cancer (CRC) is one of the most common digestive cancers leading to deaths worldwide. In this study, we aimed to investigate the diagnostic value of miR-663 in CRC. The expression of miR-663 was detected by quantitative real-time reverse transcriptase-polymerase chain reaction (qRT-PCR). The association between miR-663 and clinical parameters of subjects was evaluated by chi-square test. Additionally, ROC (receiver operating characteristic) analysis was performed to evaluate the diagnostic role of miR-663 in CRC. The expression of miR-663 in CRC patients was significantly upregulated compared with benign colorectal disease patients and healthy controls (p < .01). Besides, the expression of miR-663 was significantly associated with tumour differentiation, invasion, lymph node metastasis and TNM stage (p < .05). The cutoff value of miR-663 was 1.31, and the corresponding sensitivity and specificity were 83.1% and 73.8%, respectively. In ROC analysis, the area under the curve (AUC) was 0.806, which indicated that miR-663 could act as an independent diagnostic biomarker for CRC. In conclusion, miR-663 was up-regulated in CRC patients and may be an effective biomarker for CRC diagnosis.

MicroRNA-141-3p affected proliferation, chemosensitivity, migration and invasion of colorectal cancer cells by targeting EGFR

Colorectal cancer (CRC) is one of the most often diagnosed cancers globally. MicroRNAs are small RNA molecules that play essential roles in tumorigenesis and progression of CRC. Here we evaluated the effects of miR-141-3p on growth, cetuximab sensitivity, migration and invasion of CRC cells. We found that miR-141-3p negatively regulated the proliferation, migration and invasion in CRC cells. In addition, miR-141-3p enhanced the cetuximab sensitivity of CRC cells by EGFR suppression. Moreover, miR-141-3p improved cetuximab-induced apoptosis in CRC cells. Furthermore, miR-141-3p altered the expression of E-cadherin, N-cadherin, snail and Vimentin, indicating miR-141-3p might play a role on epithelial to mesenchymal transition (EMT). Luciferase reporter assay showed that EGFR was the direct binding site of miR-141-3p and the expression levels of p-EGFR, Raf-1, pAKT and p-ERK1/2 were regulated by miR-141-3p. After down-regulation of EGFR by siRNA in CRC cells, the effects of miR-141-3p on proliferation, migration and invasion were reversed. miR-141-3p played important roles in CRC growth and response to cetuximab treatment, and might function as a potential biomarker to predict cetuximab response.

Value of microRNAs in diagnosis and prognosis of colorectal cancer

Some new treatment methods have been explored to delay the recurrence of colorectal cancer (CRC). Early diagnosis plays an important role in the improvement of curative effect. The conventional methods used to diagnose and monitor CRC are fecal occult blood test (FOBT) and colonoscopy. However, FOBT has an unsatisfactory sensitivity, while colonoscopy is expensive and invasive. As new biomarkers, microRNAs, which can be detected in CRC tissues, cells, and body fluid as tumor suppressors or oncogenes, can be used in early diagnosis, the monitoring of metastasis and treatment, as well prognostic evaluation of CRC. This article reviews the diagnostic and prognostic value of microRNAs in CRC.

Colon cancer therapy by focusing on colon cancer stem cells and their tumor microenvironment

Despite many advances and optimization in colon cancer treatment, tumor recurrence and metastases make the development of new therapies necessary. Colon cancer stem cells (CCSCs) are considered as the main triggering factor of cancer progression, recurrence, and metastasis. CCSCs as a result of accumulated genetic and epigenetic alterations and also complex interconnection with the tumor microenvironment (TME) can evolve and convert to full malignant cells. Mounting evidence suggests that in cancer therapy both CCSCs and non-CCSCs in TME have to be regarded to break through the limitation of current therapies. In this regard, stem cell capabilities of some non-CCSCs may arise inside the TME condition. Therefore, a deep knowledge of regulatory mechanisms, heterogeneity, specific markers, and signaling pathways of CCSCs and their interconnection with TME components is needed to improve the treatment of colorectal cancer and the patient's life quality. In this review, we address current different targeted therapeutic options that target cell surface markers and signaling pathways of CCSCs and other components of TME. Current challenges and future perspectives of colon cancer personalized therapy are also provided here. Taken together, based on the deep understanding of biology of CCSCs and using three-dimensional culture technologies, it can be possible to reach successful colon cancer eradication and improvise combination targeted therapies against CCSCs and TME.

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.

Clinical Correlation of miR-200c/141 Cluster DNA Methylation and miR-141 Expression with the Clinicopathological Features of Colorectal Primary Lesions/Tumors

BACKGROUND

Abnormal DNA methylation leading to altered transcription of certain genes occurs frequently in colorectal cancer (CRC). As with protein-coding genes, microRNAs (miRNAs) may be targeted for methylation in CRC; however, the methylation state of miRNA genes in CRC, especially in primary lesions, has not yet been completely elucidated. To understand the impact of DNA methylation on the miR-200c/141 cluster promoter, we investigated the methylation and expression of miR-141 in precancerous lesions and colorectal cancer.

METHODS

In this cross-sectional study, 208 colorectal tissue samples, including 34 tumor tissue samples, 60 precancerous lesions with matched normal adjacent tissues, and 20 normal tissue samples, were collected. Promoter methylation of the miR-200c/141 cluster was studied using methylation-specific PCR. MiR-141 expression was examined using quantitative real-time PCR.

RESULTS

Our findings showed that the miR-200c/141 cluster promoter region was most frequently hypermethylated in colorectal tumors and adenomatous polyps, but unmethylated in hyperplastic polyp tissues (P < 0.001). DNA methylation of the miR-200c/141 cluster and the tumor stage were significantly correlated (P = 0.002); however, miR-141 expression difference between the tumor and polyp samples was not significant (p = 0.6).

CONCLUSION

The DNA methylation status of the miR-200c/141 cluster could serve as a progression marker from benign polyps to colorectal cancer.

MiR-320a was highly expressed in postmenopausal osteoporosis and acts as a negative regulator in MC3T3E1 cells by reducing MAP9 and inhibiting PI3K/AKT signaling pathway

BACKGROUND

Postmenopausal osteoporosis (PMO), as a frequent disease in postmenopausal women, is mainly caused by the lack of estrogen. MiR-320a has been found to abate osteoblast function and induce oxidative stress before osteoporosis. However, studies on the downstream target gene and related signaling pathway of miR-320a in PMO are still obscure. This study aims to deal with these problems.

METHODS

The expression levels of miR-320a and microtubule-associated protein 9 (MAP9) in patients with osteoporosis were analyzed on the basis of the GEO database. The cells viability was determined by methylthiazolyl tetrazolium bromide (MTT). Flow cytometry and western blot were used to detect the cells apoptosis and the expression of apoptosis-related proteins, respectively. The cells differentiation-related proteins were detected by qRT-PCR and western blot. The interaction between miR-320a and MAP9 was predicted by biological software and verified by dual luciferase reporter assay and rescue assay. The expression levels of PI3K, p-PI3K, AKT and p-AKT in MC3T3-E1 cells were assessed by western blot.

RESULTS

We observed that miR-320a was over-expressed in PMO patients and exhibited inhibitory effects on MC3T3-E1 cells activity and differentiation, as well as promoting effects on MC3T3-E1 cells apoptosis. MAP9 was verified as a target gene of miR-320a and was negatively regulated by miR-320a. Based on the GEO database, MAP9 was found to be lower expressed in PMO patients. Rescue assay demonstrated that down-regulation of MAP9 could alleviate the promoting effects of miR-320a inhibitor on MC3T3-E1 cells activity and differentiation and the inhibitory effects of miR-320a inhibitor on MC3T3-E1 cells apoptosis. Mechanically, miR-320a/MAP9 possibly took part in MC3T3-E1 cells viability, differentiation and apoptosis via mediating PI3K/AKT signaling pathway.

CONCLUSIONS

Our outcomes demonstrated that miR-320a promoted MC3T3-E1 cells apoptosis, suppressed MC3T3-E1 cells viability and differentiation through targeting MAP9 and modulating PI3K/AKT signaling pathway, which provided theoretical support for miR-320a/MAP9 as promising targets for the treatment and prevention of PMO.

MicroRNA-23a promotes colorectal cancer cell migration and proliferation by targeting at MARK1

The functional role of microRNA-23a in tumorigenesis has been investigated; however, the exact mechanism of microRNA-23a (miR-23a) in colorectal cancer development has not been fully explored. In the present study, we aimed to investigate the molecular functional role of miR-23a in colorectal carcinogenesis. Quantitative real-time polymerase chain reaction was conducted to investigate the expression level of miR-23a in tissue samples and cell lines (HCT116 and SW480). CCK-8, colony formation and Transwell assay were used to explore the role of miR-23a in cell proliferation and migration. Dual luciferase reporter assay was used to identify the direct binding of miR-23a with its target, MARK1. Western blot analysis was used to analyze the expression level of MARK1, as well as a confirmed miR-23a target gene, MTSS1, in miR-23a-mimic and miR-23a-inhibit groups. Rescue experiments were conducted by overexpression of MARK1 in miR-23a-mimic-transfected cell lines. The results showed that miR-23a was highly expressed in colorectal cancer tissue and cell lines. MiR-23a could promote proliferation and migration of colorectal cancer cell lines. MARK1 was a direct target of miR-23a and the expression level of MARK1 was down-regulated in miR-23a-mimic-transfected cell lines but up-regulated in miR-23a-inhibit-transfected cells. Overexpression of MARK1 could partly reverse the cancer-promoting function of miR-23a. Our results suggested that miR-23a promotes colorectal cancer cell proliferation and migration by mediating the expression of MARK1. MiR-23a may be a potential therapeutic target for colorectal cancer treatment.

Association between non-alcoholic fatty liver disease and colorectal cancer

Introduction: Colorectal cancer (CRC) is a common malignancy, ranking fourth among the causes of cancer-related deaths globally. Its incidence has increased in recent decades, and now more than one million CRC patients are diagnosed and thousands die annually. The 5-year survival rate varies with the stage at diagnosis, are approximately 90% in the early stages of disease, and less than 10% in advanced disease. Non-alcoholic fatty liver disease (NAFLD), which is a major cause of chronic liver disease, and characterized by the accumulation of fat in hepatocytes, has also emerged as a risk factor for CRC, and to be related with the development of colorectal polyps. Areas covered: The purpose of this current review is to summarize the main findings of studies that have investigated the role of NAFLD in development of CRC. Expert opinion: Various molecular pathways are altered during the development of NAFLD, which are also important in CRC tumorigenesis. There is growing body of evidence showing the potential role of activation of pro-inflammatory, disruption of anti-inflammatory pathways, increasing the activity of pathways involved in cell proliferation/survival. Thus targeting these dysregulated pathways via novel inhibitors can be a potential therapy for CRC prevention in cases with NAFLD.

Systemic miRNA delivery by nontoxic nanoscale coordination polymers limits epithelial-to-mesenchymal transition and suppresses liver metastases of colorectal cancer

Though early detection and treatment of primary tumors has significantly improved in recent years, metastatic disease remains among the most significant challenges in cancer therapy. Cancer cells can disseminate before the primary tumor is detected to form micro or gross metastases, requiring toxic systemic therapies. To prevent and suppress metastases, we have developed a nontoxic, long-circulating nanoscale coordination polymer (NCP) protecting microRNA (miRNA) in circulation and releasing it in tumors. PtIV(en)2 [en = ethylenediamine] containing NCPs (PtEN) can release a nontoxic, kinetically inert PtII(en)2 compound and carbon dioxide which aids the endosomal escape of its miRNA cargo, miR-655-3p. Without the presence of the PtEN core, the miRNA showed cellular uptake but no effect. When transfected into human colorectal HCT116 cells by NCPs, this oligometastatic miRNA limited proliferation and epithelial-to-mesenchymal transition by preventing β-catenin nuclear translocation and tumor cell invasion. Systemic administrations of PtEN/miR-655-3p sustained effective transfection to reduce liver colonization and tumor burden in a xenogenic hepatic metastatic model of HCT116 without any observable toxicity.

Circulating biomarkers for early detection and clinical management of colorectal cancer

New non-invasive approaches that can complement and improve on current strategies for colorectal cancer (CRC) screening and management are urgently needed. A growing number of publications have documented that components of tumors, which are shed into the circulation, can be detected in the form of liquid biopsies and can be used to detect CRC at early stages, to predict response to certain therapies and to detect CRC recurrence in a minimally invasive way. The analysis of circulating tumor DNA (ctDNA), tumor-derived cells (CTC, circulating tumor cells) or circulating microRNA (miRNA) in blood and other body fluids, have a great potential to improve different aspects of CRC management. The challenge now is to find which types of components, biofluids and detection methods would be the most suitable to be applied in the different steps of CRC detection and treatment. This chapter will provide an up to date review on ctDNA, CTCs and circulating miRNAs as new biomarkers for CRC, either for clinical management or early detection, highlighting their advantages and limitations.

The expression level changes of microRNAs 200a/205 in the development of invasive properties in gastric cancer cells through epithelial-mesenchymal transition

EMT (Epithelial-Mesenchymal Transition) is a highly regulated process that results in cancer progression. MicroRNA plays a significant role in the regulation of EMT through tight control of the transcription factors. In this study, we focus on miR-200a/205 as a factor involved in the control of the EMT process in gastric cancer cells. In this sense, gastric adenocarcinoma cell lines were used to induce EMT process. For characterization of EMT process, the mRNA levels of E-cadherin, Vimentin, β-catenin, ZEB1 and Snail were measured by real time PCR. In addition, Western blot approach was adopted to determine the protein levels of these EMT markers. Transwell assay revealed migration and invasion property of gastric cancer cell after EMT induction. To analyze alteration amount of microRNAs, RT-PCR was applied. Our results confirmed the establishment of in vitro EMT model. In vitro study showed a significant negative correlation between the expression of miR-200a (P = 0.001) and expression level of EMT markers. Nevertheless, miR-205 did not show any significant results in correlation with EMT in AGS cell line. All in vitro results also were validated in gastric cancer tissue samples. Based on our findings from gastric cancer sample patients and in vitro results, miR-200a is down regulated. Therefore, in further investigation, miR-200a could be used as a candidate to prevent the invasive properties of gastric cancer through the EMT process.

The emergence of melatonin in oncology: Focus on colorectal cancer

Within the last few decades, melatonin has increasingly emerged in clinical oncology as a naturally occurring bioactive molecule with substantial anticancer properties and a pharmacological profile optimal for joining the currently available pharmacopeia. In addition, extensive experimental data shows that this chronobiotic agent exerts oncostatic effects throughout all stages of tumor growth, from initial cell transformation to mitigation of malignant progression and metastasis; additionally, melatonin alleviates the side effects and improves the welfare of radio/chemotherapy-treated patients. Thus, the support of clinicians and oncologists for the use of melatonin in both the treatment and proactive prevention of cancer is gaining strength. Because of its epidemiological importance and symptomatic debut in advanced stages of difficult clinical management, colorectal cancer (CRC) is a preferential target for testing new therapies. In this regard, the development of effective forms of clinical intervention for the improvement of CRC outcome, specifically metastatic CRC, is urgent. At the same time, the need to reduce the costs of conventional anti-CRC therapy results is also imperative. In light of this status quo, the therapeutic potential of melatonin, and the direct and indirect critical processes of CRC malignancy it modulates, have aroused much interest. To illuminate the imminent future on CRC research, we focused our attention on the molecular mechanisms underlying the multiple oncostatic actions displayed by melatonin in the onset and evolution of CRC and summarized epidemiological evidence, as well as in vitro, in vivo and clinical findings that support the broadly protective potential demonstrated by melatonin.

Downregulation of miR-222-3p Reverses Doxorubicin-Resistance in LoVo Cells Through Upregulating Forkhead Box Protein P2 (FOXP2) Protein

BACKGROUND Doxorubicin (DOX) is a potent chemotherapeutic agent used to treat colon cancer. Despite impressive initial clinical responses, drug resistance has dramatically compromised the effectiveness of DOX. However, the underlying mechanisms of chemotherapeutic resistance in colon cancer remain poorly understood. MATERIAL AND METHODS In this study, we compared the expression of miR-222-3p in DOX-resistant colon cancer cells (LoVo/ADR) with the corresponding DOX-sensitive parental cells (LoVo/S) using quantitative real-time PCR. In addition, miR-222-3p inhibitors were infected into LoVo/ADR cell lines and the effects of this treatment were assessed. The Cell Counting Kit 8 assay was employed to verify the sensitivity of colon cancer cell lines to DOX. EdU (5-ethynyl-2'-deoxyuridine) assay, flow cytometry, and in vivo subcutaneous tumorigenesis were used to assess cell proliferation and apoptosis. Transwell and wound healing assays were used to investigate cell migration after adding DOX. Additionally, the expression of forkhead box protein P2 (FOXP2), P-glycoprotein (P-gp) and caspase pathway-associated markers was assessed by western blotting. RESULTS Our results showed that miR-222-3p was upregulated in LoVo/ADR compared with the expression in LoVo/S cells. Additionally, downregulation of miR-222-3p in LoVo/ADR cells increased their sensitivity to DOX, reduced P-gp expression, and activated the caspase pathway. However, the downregulation of FOXP2 could efficiently reverse the effect of miR-222-3p inhibitors on LoVo/ADR cells. CONCLUSIONS Taken together, our results showed that miR-222-3p induced DOX resistance via suppressing FOXP2, upregulating P-gp, and inhibiting the caspase pathway.

Small non-coding RNA and colorectal cancer

Colorectal cancer (CRC) is the third most common malignance. Although great efforts have been made to understand the pathogenesis of CRC, the underlying mechanisms are still unclear. It is now clear that more than 90% of the total genome is actively transcribed, but lack of protein‐coding potential. The massive amount of RNA can be classified as housekeeping RNAs (such as ribosomal RNAs, transfer RNAs) and regulatory RNAs (such as microRNAs [miRNAs], PIWI‐interacting RNA [piRNAs], tRNA‐derived stress‐induced RNA, tRNA‐derived small RNA [tRFs] and long non‐coding RNAs [lncRNAs]). Small non‐coding RNAs are a group of ncRNAs with the length no more than 200 nt and they have been found to exert important regulatory functions under many pathological conditions. In this review, we summarize the biogenesis and functions of regulatory sncRNAs, such as miRNAs, piRNA and tRFs, and highlight their involvements in cancers, particularly in CRC.

Apiaceous and Cruciferous Vegetables Fed During the Post-Initiation Stage Reduce Colon Cancer Risk Markers in Rats

BACKGROUND

Vegetable consumption reduces colon cancer risk when fed in the initiation stage of carcinogenesis; however, the effect of vegetable consumption during the post-initiation stage has rarely been examined.

OBJECTIVE

We investigated the chemopreventive effects of feeding apiaceous and cruciferous vegetables on colon cancer risk in the post-initiation stage.

METHODS

Thirty male Wistar rats (∼5 wk, 92 g) were subcutaneously injected with 1,2-dimethylhydrazine 1 time/wk for 2 wk. One week after the last dose, rats were randomly assigned to 3 groups: the basal diet, an apiaceous vegetable-containing diet (API; 21% fresh wt/wt), or a cruciferous vegetable-containing diet (CRU; 21% fresh wt/wt). All diets contained ∼20% protein, 7% fat, and 63% digestible carbohydrate. Experimental diets were fed for 10 wk, after which colons were harvested.

RESULTS

CRU reduced aberrant crypt foci (ACF) number compared to the basal group (P = 0.014) and API (P = 0.013), whereas API decreased the proportion of dysplastic ACF relative to the basal group (P < 0.05). Both CRU and API reduced doublecortin-like kinase 1-positive marker expression relative to basal by 57.9% (P = 0.009) and 51.4% (P < 0.02). The numbers of CD44-positive ACF did not differ between the groups. We identified 14 differentially expressed microRNAs (miRNAs). Of these, expression of 6 miRNAs were greater or tended to be greater (P ≤ 0.10) in one or both vegetable-containing groups compared to the basal group. Bioinformatic analysis of these expression changes in miRNA predicted a change in WNT/β-catenin signaling, indicating downregulation of β-catenin in the vegetable-fed groups. Consistent with this bioinformatics analysis, β-catenin-accumulated ACF were decreased in CRU (93.1%, P = 0.012), but not in API (54.4%, P = 0.125), compared to the basal group.

CONCLUSION

Both apiaceous and cruciferous vegetables, fed post-initiation, reduce colonic preneoplastic lesions as well as cancer stem cell marker expression in rats, possibly by suppressing oncogenic signaling through changes in miRNA expression.

Biomarkers for Stratification in Colorectal Cancer: MicroRNAs

Colorectal cancer (CRC) is one of the most widely recognized and deadly malignancies worldwide. In spite of the fact that the death rates have declined over the previous decade, particularly because of enhanced screening or potential treatment alternatives, CRC still remains the third leading cause of cancer-related mortality in the world, with an estimated incidence of over 1 million new cases and approximately 600 000 deaths estimated yearly. Unlike prostate and lung cancer, CRC is not easily detectable in its early stage, which may also account for its high mortality rate. MicroRNAs (miRNAs) are a class of noncoding RNAs. The roles of these noncoding RNAs have been implicated in cancer pathogenesis, most especially CRC, due to their ability to posttranscriptionally regulate the expression of oncogenes and tumor suppressor genes. Dysregulated expression of many miRNAs regulates the expression of hundreds of growth regulatory genes and pathways that are important in the multistep model of colorectal carcinogenesis. If CRC is detected early, it is a largely treatable disease. Early diagnosis, including the identification of premalignant adenomas, is regarded a major concept for improving patient survival in CRC treatment. Several lines of research suggest that miRNAs are closely implicated in the metastatic process in CRC and some of these miRNAs could be useful as promising clinical tools for identifying specific stages of CRC due to their differential expression. This review discusses the correlation between CRC staging relative to the specific expression of miRNA for early detection, treatment, and disease management.

An Integrated Approach for Identification of Functionally Similar MicroRNAs in Colorectal Cancer

Colorectal cancer (CRC) is one of the most prevalent cancers around the globe. However, the molecular reasons for pathogenesis of CRC are still poorly understood. Recently, the role of microRNAs or miRNAs in the initiation and progression of CRC has been studied. MicroRNAs are small, endogenous noncoding RNAs found in plants, animals, and some viruses, which function in RNA silencing and posttranscriptional regulation of gene expression. Their role in CRC development is studied and they are found to be potential biomarkers in diagnosis and treatment of CRC. Therefore, identification of functionally similar CRC related miRNAs may help in the development of a prognostic tool. In this regard, this paper presents a new algorithm, called μSim. It is an integrative approach for identification of functionally similar miRNAs associated with CRC. It integrates judiciously the information of miRNA expression data and miRNA-miRNA functionally synergistic network data. The functional similarity is calculated based on both miRNA expression data and miRNA-miRNA functionally synergistic network data. The effectiveness of the proposed method in comparison to other related methods is shown on four CRC miRNA data sets. The proposed method selected more significant miRNAs related to CRC as compared to other related methods.

Molecular characterization and biomarker identification in colorectal cancer: Toward realization of the precision medicine dream

Colorectal cancer (CRC) is a major public health problem, both in the USA and globally. Over the past 20 years, significant advances have been made in the treatment of patients with metastatic CRC (mCRC). Recent efforts in the field of biomarkers have focused on the development of molecular diagnostics to define the subset of patients with mCRC that is likely to derive most benefit from anti-EGFR therapy. Herein, we review the recent advancements in molecular stratification of CRC and the role of current as well as emerging biomarkers in this disease. It is now clear that the presence of activating mutations in the KRAS and NRAS genes serves as reliable predictive markers for resistance to anti-EGFR therapy in mCRC. It is also clear that further improvements in the survival of mCRC patients will probably be made possible only with identification of new predictive molecular biomarkers and their evaluation using rational and innovative clinical trials. The recent advances in DNA sequencing technology and "omics"-based approaches have provided promising new strategies for the development of novel molecular biomarkers in this disease.

microRNA biomarkers in colorectal cancer liver metastasis

Liver metastasis is a primary factor of prognosis and long-term survival for patients diagnosed with colorectal cancer (CRC). Colorectal cancer liver metastasis (CRCLM), is a complex biological process involving multiple factors and steps, and its mechanisms are yet to be discovered. In recent years, small noncoding RNAs, especially microRNAs (miRNAs) have been proven to play an important role in tumorigenesis, progression and metastasis in a variety of cancers, including CRC. Increasing evidence suggests that miRNAs, including those from exosomes secreted by tumor cells in circulation, could be used as promising biomarkers in early cancer detection, treatment, and prognosis. In this review, we focus on the functional roles and clinical applications of miRNAs, especially those from circulating exosomes secreted by tumor cells related to CRCLM.

Decreased miR-320 expression is associated with breast cancer progression, cell migration, and invasiveness via targeting Aquaporin 1

Our previous studies have demonstrated that Aquaporin 1 (AQP1) is overexpressed in breast cancer. However, the mechanism remains elusive. MicroRNA 320 (miR-320) downregulation has been reported in various types of cancers, and it may regulate AQP1 expression. In this study, miR-320 and AQP1 expressions were investigated by quantitative reverse transcription-PCR, in situ hybridization, and immunohistochemistry. The clinicopathological implications of these molecules were also analyzed. We found that miR-320 expression is downregulated in both plasma and tumor tissue in human breast cancer patients. Survival analysis showed that reduced expression of miR-320 and overexpression of AQP1 are associated with worse prognosis. Luciferase assays showed that miR-320 negatively regulates AQP1 expression. In addition, cell proliferation, migration, and invasion assays were performed to investigate the effects of miR-320 on breast cancer cells. Our results showed that miR-320 overexpression inhibits cell proliferation, migration, and invasion in breast cancer cells by downregulating AQP1. These observations suggested that miR-320 downregulation may enhance AQP1 expression in breast cancer, favoring tumor progression. Our findings indicated that miR-320 and AQP1 may serve as prognostic biomarkers and therapeutic targets in the treatment of breast cancer.

Oral hygiene might prevent cancer

Many evidences support that species from the Human Oral Microbiome Database such as Fusobacterium nucleatum or Bacteroides, linked previously to periodontitis and appendicitis, play a role in colorectal cancer (CRC), including metastasis. These typically oral species are invasive anaerobes that form biofilms in their virulent state. Aspirin (a NSAID) has been recently included into routine CRC prevention rationale. NSAIDs can prevent the growth of neoplastic lesions by inhibiting COX enzymes and another set of recently identified COX-independent targets, which include the WNT, AMPK and MTOR signaling pathways, the crosstalk between nucleoli and NF-κB transcriptional activity in apoptosis, and the biochemistry of platelets. These are signaling pathways related to tumor-promoting inflammation. In this process, pathogens or simple deregulation of the microbiota play an important role in CRC. Aspirin and other NSAIDs are efficient inhibitors of biofilm formation and able to control periodontitis development preventing inflammation related to the microbiota of the gingival tissue, so its seems plausible to include this pathway in the mechanisms that aspirin uses to prevent CRC. We propose arguments suggesting that current oral hygiene methods and other future developments against periodontitis might prevent CRC and probably other cancers, alone or in combination with other options; and that the multidisciplinary studies needed to prove this hypothesis might be relevant for cancer prevention.