Competitive endogenous RNA networks: Decoding the role of long non-coding RNAs and circular RNAs in colorectal cancer chemoresistance.

Colorectal cancer (CRC) is recognized as one of the most common gastrointestinal malignancies across the globe. Despite significant progress in designing novel treatments for CRC, there is a pressing need for more effective therapeutic approaches. Unfortunately, many patients undergoing chemotherapy develop drug resistance, posing a significant challenge for cancer treatment. Non-coding RNAs (ncRNAs) have been found to play crucial roles in CRC development and its response to chemotherapy. However, there are still gaps in our understanding of interactions among various ncRNAs, such as long non-coding RNAs (lncRNAs), circular RNAs (circRNAs) and microRNAs (miRNAs). These ncRNAs can act as either oncogenes or tumour suppressors, affecting numerous biological functions in different cancers including CRC. A class of ncRNA molecules known as competitive endogenous RNAs (ceRNAs) has emerged as a key player in various cellular processes. These molecules form networks through lncRNA/miRNA/mRNA and circRNA/miRNA/mRNA interactions. In CRC, dysregulation of ceRNA networks has been observed across various cellular processes, including proliferation, apoptosis and angiogenesis. These dysregulations are believed to play a significant role in the progression of CRC and, in certain instances, may contribute to the development of chemoresistance. Enriching our knowledge of these dysregulations holds promise for advancing the field of diagnostic and therapeutic modalities for CRC. In this review, we discuss lncRNA- and circRNA-associated ceRNA networks implicated in the emergence and advancement of drug resistance in colorectal carcinogenesis.

Exosomes released by oxidative stress-induced mesenchymal stem cells promote murine mammary tumor progression through activating the STAT3 signaling pathway.

Mesenchymal stem cells (MSCs) may play a pivotal role in shaping the tumor microenvironment (TME), influencing tumor growth. Nonetheless, conflicting evidence exists regarding the distinct impacts of MSCs on tumor progression, with some studies suggesting promotion while others indicate suppression of tumor cell growth. Considering that oxidative stress is implicated in the dynamic interaction between components of the TME and tumor cells, we investigated the contribution of exosomes released by hydrogen peroxide (H2O2)-treated MSCs to murine mammary tumor growth and progression. Additionally, we aimed to identify the underlying mechanism through which MSC-derived exosomes affect breast tumor growth and angiogenesis. Our findings demonstrated that exosomes released by H2O2-treated, stress-induced MSCs (St-MSC Exo) promoted breast cancer cell progression by inducing the expression of vascular endothelial growth factor (VEGF) and markers associated with epithelial-to-mesenchymal transition. Further clarification revealed that the promoting effect of St-MSC Exo on VEGF expression may, in part, depend on activating STAT3 signaling in BC cells. In contrast, exosomes derived from untreated MSCs retarded JAK1/STAT3 phosphorylation and reduced VEGF expression. Additionally, our observations revealed that the activation of the transcription factor NF-κB in BC cells, stimulated with St-MSC Exo, occurs concurrently with an increase in intracellular ROS production. Moreover, we observed that the increase in VEGF secretion into the conditioned media of 4T1 BC, mediated by St-MSC Exo, positively influenced endothelial cell proliferation, migration, and vascular behavior in vitro. In turn, our in vivo studies confirmed that St-MSC Exo, but not exosomes derived from untreated MSCs, exhibited a significant promoting effect on breast tumorigenicity. Collectively, our findings provide new insights into how MSCs may contribute to modulating the TME. We propose a novel mechanism through which exosomes derived from oxidative stress-induced MSCs may contribute to tumor progression and angiogenesis.

Propagation Capacity of Phage Display Peptide Libraries Is Affected by the Length and Conformation of Displayed Peptide.

The larger size and diversity of phage display peptide libraries enhance the probability of finding clinically valuable ligands. A simple way of increasing the throughput of selection is to mix multiple peptide libraries with different characteristics of displayed peptides and use it as biopanning input. In phage display, the peptide is genetically coupled with a biological entity (the phage), and the representation of peptides in the selection system is dependent on the propagation capacity of phages. Little is known about how the characteristics of displayed peptides affect the propagation capacity of the pooled library. In this work, next-generation sequencing (NGS) was used to investigate the amplification capacity of three widely used commercial phage display peptide libraries (Ph.D.™-7, Ph.D.™-12, and Ph.D.™-C7C from New England Biolabs). The three libraries were pooled and subjected to competitive propagation, and the proportion of each library in the pool was quantitated at two time points during propagation. The results of the inter-library competitive propagation assay led to the conclusion that the propagation capacity of phage libraries on a population level is decreased with increasing length and cyclic conformation of displayed peptides. Moreover, the enrichment factor (EF) analysis of the phage population revealed a higher propagation capacity of the Ph.D.TM-7 library. Our findings provide evidence for the contribution of the length and structural conformation of displayed peptides to the unequal propagation rates of phage display libraries and suggest that it is important to take peptide characteristics into account once pooling multiple combinatorial libraries for phage display selection through biopanning.

Depth of Sequencing Plays a Determining Role in the Characterization of Phage Display Peptide Libraries by NGS.

Next-generation sequencing (NGS) has raised a growing interest in phage display research. Sequencing depth is a pivotal parameter for using NGS. In the current study, we made a side-by-side comparison of two NGS platforms with different sequencing depths, denoted as lower-throughput (LTP) and higher-throughput (HTP). The capacity of these platforms for characterization of the composition, quality, and diversity of the unselected Ph.D.TM-12 Phage Display Peptide Library was investigated. Our results indicated that HTP sequencing detects a considerably higher number of unique sequences compared to the LTP platform, thus covering a broader diversity of the library. We found a larger percentage of singletons, a smaller percentage of repeated sequences, and a greater percentage of distinct sequences in the LTP datasets. These parameters suggest a higher library quality, resulting in potentially misleading information when using LTP sequencing for such assessment. Our observations showed that HTP reveals a broader distribution of peptide frequencies, thus revealing increased heterogeneity of the library by the HTP approach and offering a comparatively higher capacity for distinguishing peptides from each other. Our analyses suggested that LTP and HTP datasets show discrepancies in their peptide composition and position-specific distribution of amino acids within the library. Taken together, these findings lead us to the conclusion that a higher sequencing depth can yield more in-depth insights into the composition of the library and provide a more complete picture of the quality and diversity of phage display peptide libraries.

Analysis of Compositional Bias in a Commercial Phage Display Peptide Library by Next-Generation Sequencing.

The principal presumption of phage display biopanning is that the naïve library contains an unbiased repertoire of peptides, and thus, the enriched variants derive from the affinity selection of an entirely random peptide pool. In the current study, we utilized deep sequencing to characterize the widely used Ph.DTM-12 phage display peptide library (New England Biolabs). The next-generation sequencing (NGS) data indicated the presence of stop codons and a high abundance of wild-type clones in the naïve library, which collectively result in a reduced effective size of the library. The analysis of the DNA sequence logo and global and position-specific frequency of amino acids demonstrated significant bias in the nucleotide and amino acid composition of the library inserts. Principal component analysis (PCA) uncovered the existence of four distinct clusters in the naïve library and the investigation of peptide frequency distribution revealed a broad range of unequal abundances for peptides. Taken together, our data provide strong evidence for the notion that the naïve library represents substantial departures from randomness at the nucleotide, amino acid, and peptide levels, though not undergoing any selective pressure for target binding. This non-uniform sequence representation arises from both the M13 phage biology and technical errors of the library construction. Our findings highlight the paramount importance of the qualitative assessment of the naïve phage display libraries prior to biopanning.

CASC11 and PVT1 spliced transcripts play an oncogenic role in colorectal carcinogenesis.

Cancer is fundamentally a genetic disorder that alters cellular information flow toward aberrant growth. The coding part accounts for less than 2% of the human genome, and it has become apparent that aberrations within the noncoding genome drive important cancer phenotypes. The numerous carcinogenesis-related genomic variations in the 8q24 region include single nucleotide variations (SNVs), copy number variations (CNVs), and viral integrations occur in the neighboring areas of the MYC locus. It seems that MYC is not the only target of these alterations. The MYC-proximal mutations may act via regulatory noncoding RNAs (ncRNAs). In this study, gene expression analyses indicated that the expression of some PVT1 spliced linear transcripts, CircPVT1, CASC11, and MYC is increased in colorectal cancer (CRC). Moreover, the expression of these genes is associated with some clinicopathological characteristics of CRC. Also, in vitro studies in CRC cell lines demonstrated that CASC11 is mostly detected in the nucleus, and different transcripts of PVT1 have different preferences for nuclear and cytoplasmic parts. Furthermore, perturbation of PVT1 expression and concomitant perturbation in PVT1 and CASC11 expression caused MYC overexpression. It seems that transcription of MYC is under regulatory control at the transcriptional level, i.e., initiation and elongation of transcription by its neighboring genes. Altogether, the current data provide evidence for the notion that these noncoding transcripts can significantly participate in the MYC regulation network and in the carcinogenesis of colorectal cells.

A White Plaque, Associated with Genomic Deletion, Derived from M13KE-Based Peptide Library Is Enriched in a Target-Unrelated Manner during Phage Display Biopanning Due to Propagation Advantage.

The nonspecific enrichment of target-unrelated peptides during biopanning remains a major drawback for phage display technology. The commercial Ph.D.TM-7 phage display library is used extensively for peptide discovery. This library is based on the M13KE vector, which carries the lacZα sequence, leading to the formation of blue plaques on IPTG-X-gal agar plates. In the current study, we report the isolation of a fast-propagating white clone (displaying WSLGYTG peptide) identified through screening against a recombinant protein. Sanger sequencing demonstrated that white plaques are not contamination from environmental M13-like phages, but derive from the library itself. Whole genome sequencing revealed that the white color of the plaques results from a large 827-nucleotide genomic deletion. The phenotypic characterization of propagation capacity through plaque count- and NGS-based competitive propagation assay supported the higher propagation rate of Ph-WSLGYTG clone compared with the library. According to our data, white plaques are likely to arise endogenously in Ph.D. libraries due to mutations in the M13KE genome and should not always be viewed as exogenous contamination. Our findings also led to the conclusion that the deletion observed here might be an ancestral mutation already present in the naïve library, which causes target-unrelated nonspecific enrichment of white clone during biopanning due to propagation advantage.

Identification of a novel colon adenocarcinoma cell targeting peptide using phage display library biopanning.

Phage display is well recognized as a promising high-throughput screening tool for the discovery of novel cancer-targeting peptides. Here, we screened a phage display library of 7-mer random peptides through in vitro biopanning to isolate peptide ligands binding to SW480 human colon adenocarcinoma cells. Three rounds of negative and positive selection caused a remarkable enrichment of colon cancer cell-binding phage clones with a significant enhancement of phage recovery efficiency (about 157-fold). A number of phage clones were picked out from the eluted phages of last selection round and sequenced. According to the results of cell binding assay and phage cell-based ELISA, one of the isolated peptides denoted as CCBP1 (with the sequence HAMRAQP) was indicated to have the highest binding efficiency, selectivity, and specificity toward colon cancer cells with no significant binding to control cells. Peptide competitive inhibition assay revealed that binding of the phage-displayed CCBP1 is competitively inhibited by the same free peptide, suggesting that CCBP1 specific binding to the target cell is independent of the phage context. Taken together, our findings provide support for the notion that CCBP1 binds specifically to colon cancer cells and might be a potential lead candidate for targeted delivery of imaging agents or therapeutic genes/drugs to colon tumors.

Non-coding RNA-associated competitive endogenous RNA regulatory networks: Novel diagnostic and therapeutic opportunities for hepatocellular carcinoma.

Hepatocellular carcinoma (HCC), as the most prevalent liver malignancy, is annually diagnosed in more than half a million people worldwide. HCC is strongly associated with hepatitis B and C viral infections as well as alcohol abuse. Obesity and nonalcoholic fatty liver disease (NAFLD) also significantly enhance the risk of liver cancer. Despite recent improvements in therapeutic approaches, patients diagnosed in advanced stages show poor prognosis. Accumulating evidence provides support for the regulatory role of non-coding RNAs (ncRNAs) in cancer. There are a variety of reports indicating the regulatory role of microRNAs (miRNAs) in different stages of HCC. Long non-coding RNAs (LncRNAs) exert their effects by sponging miRNAs and controlling the expression of miRNA-targeted genes. Circular RNAs (circRNAs) perform their biological functions by acting as transcriptional regulators, miRNA sponges and protein templates. Diverse studies have illustrated that dysregulation of competing endogenous RNA networks (ceRNETs) is remarkably correlated with HCC-causing diseases such as chronic viral infections, nonalcoholic steatohepatitis and liver fibrosis/cirrhosis. The aim of the current article was to provide an overview of the role and molecular mechanisms underlying the function of ceRNETs that modulate the characteristics of HCC such as uncontrolled cell proliferation, resistance to cell death, metabolic reprogramming, immune escape, angiogenesis and metastasis. The current knowledge highlights the potential of these regulatory RNA molecules as novel diagnostic biomarkers and therapeutic targets in HCC.

Identification of dysregulated competing endogenous RNA networks in glioblastoma: A way toward improved therapeutic opportunities.

Glioblastoma is recognized as one of the leading causes of death worldwide. Although there have been considerable advancements in understanding the causative molecular mechanisms of this malignancy, effective therapeutic strategies are still in limited use. It has been revealed that non-coding RNAs (ncRNAs) play critical roles in glioblastoma development, while interactions between the regulatory molecules such as long ncRNAs (lncRNAs), microRNAs (miRNAs), transcribed pseudogenes, and circular RNAs (circRNAs) remain to be fully deciphered. Over the recent years, researchers have discovered a new category of RNA molecules called competing endogenous RNA (ceRNA). This kind of RNA can contribute to molecular interactions in the form of ceRNA networks (ceRNETs). Multiple lines of evidence have demonstrated that dysregulation of various ceRNA networks is involved in glioblastoma development. Therefore, gaining insights into these dysregulations might offer potential for the early diagnosis of glioblastoma patients and identification of efficient therapeutic targets. In this review, we provide an overview of recent discoveries on ceRNA networks and the involvement of dysregulated networks in posing limitations to temozolomide therapy. We also describe signaling pathways relevant to the progression of glioblastoma.

Critical regulatory levels in tumor differentiation: Signaling pathways, epigenetics and non-coding transcripts.

Approaches to induce tumor differentiation often result in manageable and therapy-naïve cellular states in cancer cells. This transformation is achieved by activating pathways that drive tumor cells away from plasticity, a state that commonly correlates with enhanced aggression, metastasis and resistance to therapy. Here, we discuss signaling pathways, epigenetics and non-coding RNAs as three main regulatory levels with the potential to drive tumor differentiation and hence as potential targets in differentiation therapy approaches. The success of an effective therapeutic regimen in one cancer, however, does not necessarily sustain across cancer types; a phenomenon largely resulting from heterogeneity in the genetic and physiological landscapes of tumor types necessitating an approach designed for each cancer's unique genetic and phenotypic build-up.

The oncogenic and tumor suppressive roles of RNA-binding proteins in human cancers.

Posttranscriptional regulation is a mechanism for the cells to control gene regulation at the RNA level. In this process, RNA-binding proteins (RBPs) play central roles and orchestrate the function of RNA molecules in multiple steps. Accumulating evidence has shown that the aberrant regulation of RBPs makes  contributions to the initiation and progression of tumorigenesis via numerous mechanisms such as genetic changes, epigenetic alterations, and noncoding RNA-mediated regulations. In this article, we review the effects caused by RBPs and their functional diversity in the malignant transformation of cancer cells that occurs through the involvement of these proteins in various stages of RNA regulation including alternative splicing, stability, polyadenylation, localization, and translation. Besides this, we review the various interactions between RBPs and other crucial posttranscriptional regulators such as microRNAs and long noncoding RNAs in the pathogenesis of cancer. Finally, we discuss the potential approaches for targeting RBPs in human cancers.

Docosahexaenoic acid reverses the promoting effects of breast tumor cell-derived exosomes on endothelial cell migration and angiogenesis.

AIM: As a natural compound, docosahexaenoic acid (DHA) exerts anti-cancer and anti-angiogenesis functions through exosomes; however, little is known about the molecular mechanisms. MAIN METHODS: Breast cancer (BC) cells were treated with DHA (50 µM) and then tumor cell-derived exosomes (TDEs) were collected and characterized by electron microscopy, dynamic light scattering, and western blot analyses. By the time the cells were treated with DHA, RT-qPCR was used to investigate the expression of vascular endothelial growth factor (VEGF) and the selected pro- and anti-angiogenic microRNAs (miRNAs). The quantification of secreted VEGF protein was measured by enzyme-linked immunosorbent assay (ELISA). The effects of TDEs on endothelial cell angiogenesis were explored by transwell cell migration and in vitro vascular tube formation assays. KEY FINDINGS: DHA treatment caused a significant and time-dependent decrease in the expression and secretion of VEGF in/from BC cells. This also increased expression of anti-angiogenic miRNAs (i.e. miR-34a, miR-125b, miR-221, and miR-222) while decreased levels of pro-angiogenic miRNAs (i.e. miR-9, miR-17-5p, miR-19a, miR-126, miR-130a, miR-132, miR-296, and miR-378) in exosomes derived from DHA-treated BC cells, TDE (DHA+). While treatment with exosomes (100 µg/ml) obtained from untreated BC cells, TDE (DHA-), enhanced the expression of VEGF-A in human umbilical vein endothelial cells (HUVECs), incubation with DHA or TDE (DHA+) led to the significant decrease of VEGF-A transcript level in these cells. We indicated that the incubation with TDE (DHA+) could significantly decrease endothelial cell proliferation and migration and also the length and number of tubes made by HUVECs in comparison with endothelial cells incubated with exosomes obtained from untreated BC cells. SIGNIFICANCE: DHA alters angiogenesis by shifting the up-regulation of exosomal miRNA contents from pro-angiogenic to anti-angiogenic, resulting in the inhibition of endothelial cell angiogenesis. These data can help to figure out DHA's anti-cancer function, maybe its use in cancer therapy.

Insights into the roles of miRNAs; miR-193 as one of small molecular silencer in osteosarcoma therapy.

Today, cancer is one of the most common causes of death. Osteosarcoma (OS) is a tumor in long bones and its prevalence is high in teenagers and young people. Among the methods that used to treat cancer, one can name chemotherapy, surgery, and radiotherapy. Since these methods have some disadvantages and they are not absolutely successful, the use of microRNAs (miRNAs) is very useful in diagnosis and treatment of OS. MiRNAs are small non-coding RNA molecules, containing 18-25 nucleotides, which are involved in the regulation of gene expression via binding to messenger RNA (mRNA). These RNAs are divided into two classes of suppressors and oncogenes. During OS, there is aberrant expression of several miRNAs. Among these miRNAs are downregulation of miR-193 that has been associated with cancer occurrence. The aim of the current manuscript is to have overview on the treatment approaches of OS with special focus on miR-193.

Role of miR-142 in the pathogenesis of osteosarcoma and its potential as therapeutic approach.

Osteosarcoma (OS) is the most common primary malignant tumor of the bone with a strong tendency to early metastasis, and occurs in growing bones more commonly in children and adolescents. Considering the limited therapeutic methods and lack of 100% success of these methods, developing innovative therapies with high efficacy and lower side effects is needed. Meanwhile, miRNAs and the studies indicating the involvement of miRNAs in OS development have attracted attentions as a result of the frequent abnormalities in expression of miRNAs in cancer. miRNAs are noncoding short sequences with lengths ranging from 18 to 25 nucleotides that play a very important role in cellular processes, such as proliferation, differentiation, migration, and apoptosis. MiRNAs can have either oncogenic or tumor suppressive role based on cellular function and targets. This review aimed to have overview on miR-142 as a tumor suppressor in OS. Moreover, the genes involved in the disease, such as RAC1, HMAG1, MMP9, MMP2, and E-cadherin, which have irregularities as a result of change in miR-142 expression, and, thereby, result in increasing the proliferation, invasion, and metastasis of the cells in the tissues and OS cells will be discussed.

Identification of a Novel Tumor-Binding Peptide for Lung Cancer Through in-vitro Panning.

Tumor-targeted therapies are playing growing roles in cancer research. The exploitation of these powerful therapeutic modalities largely depends on the discovery of tumor-targeting ligands. Phage display has proven a promising high throughput screening tool for the identification of novel specific peptides with high binding affinity to cancer cells. In the present study, we describe the use of phage display to isolate peptide ligands binding specifically to human lung cancer cells. Towards this goal, we screened a phage display library of 7-mer random peptides in-vitro on non-small cell lung carcinoma (A549) as the target cell. Following selection rounds, there was a highly considerable enrichment of lung cancer-binding phages and a significant increase - 170 fold - of the phage recovery efficiency. After three rounds of in-vitro panning, a group of peptides with different frequencies were obtained. The binding efficiency and selectivity of these peptides for target and control cells were studied. The results of cellular binding assay and cell ELISA (enzyme-linked immunosorbent assay) revealed that LCP1 (Lung Cancer Peptide1) with the displayed sequence AWRTHTP is the most effective peptide in binding to lung cancer cells compared with normal lung epithelial cells and different non-lung tumor cells. In conclusion, our findings suggest that LCP1 may represent a novel peptide that binds specifically to lung cancer cells and further studies can pave the way for its application as a potential targeting moiety in the targeted delivery of diagnostic and therapeutic agents into lung malignant cells.

Dendrosomal nanocurcumin and exogenous p53 can act synergistically to elicit anticancer effects on breast cancer cells.

Triple-negative breast cancer (TNBC) constitutes an important histological subtype of breast cancer with a highly metastatic phenotype. The aim of the current study was to investigate the possible synergism between dendrosomal nanocurcumin (DNC) and exogenously delivered p53 in producing anticancer effects on a TNBC cell line. MTT assay was exploited to determine the viability of MDA-MB-231 cells against DNC and measure the impact of p53 overexpresssion on DNC-related cytotoxicity. Annexin-V/PI staining followed by flow cytometry and wound healing assay were used to evaluate the effects of DNC and exogenous p53, alone and in combination, on apoptosis induction and migratory capacity of MDA-MB-231 cells, respectively. Also, quantitative real-time PCR was applied to analyze the transcript levels of EMT- and metastasis-associated genes. Cell viability measurements demonstrated that DNC suppresses the proliferation of MDA-MB-231 cells in a time- and dose-dependent mode and exogenous p53 elevates the sensitivity of cells to DNC-mediated cytotoxic effects. Apoptosis and wound healing assays indicated that combination treatment with DNC and exogenous p53 leads to significantly increased apoptosis and decreased migration of breast cancer cells, compared with single treatment. The results of gene expression analysis highlighted the high potency of combination strategy to significantly reduce the expression of ZEB1 and BMI1 transcript levels. Altogether, our findings reveal that DNC and exogenous p53 act in a synergistic manner to elicit anticancer effects on MDA-MB-231 breast cancer cells. Therefore, our combination approach might be considered as a promising strategy for the development of new therapeutic modalities against breast cancer.

Down-regulation of the non-coding RNA H19 and its derived miR-675 is concomitant with up-regulation of insulin-like growth factor receptor type 1 during neural-like differentiation of human bone marrow mesenchymal stem cells.

The differentiation of human bone marrow mesenchymal stem cells (BMSCs) into specific lineages offers new opportunities to use the therapeutic efficiency of these pluripotent cells in regenerative medicine. Multiple lines of evidence have revealed that non-coding RNAs play major roles in the differentiation of BMSCs into neural cells. Here, we applied a cocktail of neural inducing factors (NIFs) to differentiate BMSCs into neural-like cells. Our data demonstrated that during neurogenic induction, BMSCs obtained a neuron-like morphology. Also, the results of gene expression analysis by qRT-PCR showed progressively increasing expression levels of neuron-specific enolase (NSE) as well as microtubule-associated protein 2 (MAP-2) and immunocytochemical staining detected the expression of these neuron-specific markers along differentiated BMSC bodies and cytoplasmic processes, confirming the differentiation of BMSCs into neuronal lineages. We also compared differences in the expression levels of the long non-coding RNA (lncRNA) H19 and H19-derived miR-675 between undifferentiated and neurally differentiated BMSCs and found that during neural differentiation down-regulation of the lncRNA H19/miR-675 axis is concomitant with up-regulation of insulin-like growth factor type-1 (IGF-1R), a well-established target of miR-675 involved in neurogenesis. The findings of the current study provide support for the hypothesis that miR-675 may confer functionality to H19, suggesting a key role for this miRNA in the neural differentiation of BSMCs. However, further investigation is required to gain deeper insights into the biological roles of this miRNA in the complex process of neurogenesis.

Regulation of MicroRNAs by Phytochemicals: A Promising Strategy for Cancer Chemoprevention.

A growing body of evidence suggests that phytochemicals are potentially able to affect a variety of cellular processes, including proliferation, apoptosis, cell-cycle control, angiogenesis, inflammation, and DNA repair. Phytochemicals may typically play pleiotropic regulatory roles in cancer cells. Chemoprevention, which can be achieved by using these natural agents, has emerged as a helpful strategy to manage a variety of malignancies. With regard to cancer-associated chemopreventive mechanisms, phytochemicals can act by modulating microRNAs (miRNAs) and their target genes. This review aims to present an overview of recent findings on the effects of some wellcharacterized bioactive phytochemicals on miRNA regulation in different cancer types. The potential use of these phytochemicals for the chemoprevention and treatment of cancer is also discussed.

Combination treatment with dendrosomal nanocurcumin and doxorubicin improves anticancer effects on breast cancer cells through modulating CXCR4/NF-κB/Smo regulatory network.

Despite advantageous antitumor properties of doxorubicin, the considerable cytotoxicity of this chemotherapeutic agent has made it necessary to develop combination treatment strategies. The aim of the current study was to investigate the possible synergism between dendrosomal nanocurcumin (DNC) and doxorubicin in eliciting anticancer effects on MDA-MB-231 metastatic breast cancer cells. The expression levels of CXCL12/CXCR4 axis and Hedgehog pathway genes were evaluated in patient-derived breast carcinoma tissues by qRT-PCR. MTT assay, Annexin V-FITC staining followed by flowcytomety and wound healing assay were used to measure the effects caused by DNC and doxorubicin, alone and in combination, on the viability, apoptosis induction, and migration of MDA-MB-231 cells, respectively. Also, qRT-PCR was exploited to analyze the expression of Smo, NF-κB and CXCR4 in cancer cells. Our results revealed that combination treatment with DNC and doxorubicin leads to significantly decreased viability, increased apoptosis, and reduced migration of breast cancer cells compared with using each drug alone. Also, combination treatment is more efficient that single treatment in reducing the expression levels of NF-κB and Smo transcripts. Our findings provide convincing support for the notion that DNC could synergistically enhance the anticancer effects of doxorubicin on metastatic breast cancer cells by improving its anti-proliferative, pro-apoptotic, and anti-migratory activities. This may be mediated, in part, by downregulating CXCR4, NF-κB, and Smo genes. Overall, the findings of the current study suggest that DNC might be used as a synergistic agent for enhancing therapeutic efficiency and reducing toxic effects of doxorubicin on breast cancer cells.