Synthesis, anticancer activity, and molecular docking of half-sandwich iron(II) cyclopentadienyl complexes with maleimide and phosphine or phosphite ligands.

In these studies, we designed and investigated the potential anticancer activity of five iron(II) cyclopentadienyl complexes bearing different phosphine and phosphite ligands. All complexes were characterized with spectroscopic analysis viz. NMR, FT-IR, ESI-MS, UV-Vis, fluorescence, XRD (for four complexes) and elemental analyses. For biological studies, we used three types of cells-normal peripheral blood mononuclear (PBM) cells, leukemic HL-60 cells and non-small-cell lung cancer A549 cells. We evaluated cell viability and DNA damage after cell incubation with these complexes. We observed that all iron(II) complexes were more cytotoxic for HL-60 cells than for A549 cells. The complex CpFe(CO)(P(OPh)3)(η1-N-maleimidato) 3b was the most cytotoxic with IC50 = 9.09 µM in HL-60 cells, IC50 = 19.16 µM in A549 and IC50 = 5.80 µM in PBM cells. The complex CpFe(CO)(P(Fu)3)(η1-N-maleimidato) 2b was cytotoxic only for both cancer cell lines, with IC50 = 10.03 µM in HL-60 cells and IC50 = 73.54 µM in A549 cells. We also found the genotoxic potential of the complex 2b in both types of cancer cells. However, the complex CpFe(CO)2(η1-N-maleimidato) 1 which we studied previously, was much more genotoxic than complex 2b, especially for A549 cells. The plasmid relaxation assay showed that iron(II) complexes do not induce strand breaks in fully paired ds-DNA. The DNA titration experiment showed no intercalation of complex 2b into DNA. Molecular docking revealed however that complexes CpFe(CO)(PPh3) (η1-N-maleimidato) 2a, 2b, 3b and CpFe(CO)(P(OiPr)3)(η1-N-maleimidato) 3c have the greatest potential to bind to mismatched DNA. Our studies demonstrated that the iron(II) complex 1 and 2b are the most interesting compounds in terms of selective cytotoxic action against cancer cells. However, the cellular mechanism of their anticancer activity requires further research.

Cell Cycle Status Influences Resistance to Apoptosis Induced by Oxidative Stress in Human Breast Cancer Cells, Which Is Accompanied by Modulation of Autophagy.

Cancer cells are characterised by uncontrolled cell proliferation; however, some of them can temporarily arrest their cell cycle at the G0 or G1 phase, which could contribute to tumour heterogeneity and drug resistance. The cell cycle status plays a critical role in chemosensitivity; however, the influence of G0- and G1-arrest has not been elucidated. To study the cell cycle arrest-mediated resistance, we used MCF-7 cells and generated three populations of cells: (1) cells arrested in the G0-like phase, (2) cells that resumed the cell cycle after the G0-like phase and (3) cells arrested in early G1 with a history of G0-like arrest. We observed that both the G0-like- and the G1-arrested cells acquired resistance to apoptosis induced by oxidative stress, accompanied by a decreased intracellular reactive oxygen species and DNA damage. This effect was associated with increased autophagy, likely facilitating their survival at DNA damage insult. The cell cycle reinitiation restored a sensitivity to oxidative stress typical for cells with a non-modulated cell cycle, with a concomitant decrease in autophagy. Our results support the need for further research on the resistance of G0- and G1-arrested cancer cells to DNA-damaging agents and present autophagy as a candidate for targeting in anticancer treatment.

Piano-stool ruthenium(II) complexes with maleimide and phosphine or phosphite ligands: synthesis and activity against normal and cancer cells.

In these studies, we designed and investigated cyto- and genotoxic potential of five ruthenium cyclopentadienyl complexes bearing different phosphine and phosphite ligands. All of the complexes were characterized with spectroscopic analysis (NMR, FT-IR, ESI-MS, UV-vis, fluorescence and XRD (for two compounds)). For biological studies, we used three types of cells - normal peripheral blood mononuclear (PBM) cells, leukemic HL-60 cells and doxorubicin-resistance HL-60 cells (HL-60/DR). We compared the results obtained with those obtained for the complex with maleimide ligand CpRu(CO)2(η1-N-maleimidato) 1, which we had previously reported. We observed that the complexes CpRu(CO)(PPh3)(η1-N-maleimidato) 2a and CpRu(CO)(P(OEt)3)(η1-N-maleimidato) 3a were the most cytotoxic for HL-60 cells and non-cytotoxic for normal PBM cells. However, complex 1 was more cytotoxic for HL-60 cells than complexes 2a and 3a (IC50 = 6.39 µM vs. IC50 = 21.48 µM and IC50 = 12.25 µM, respectively). The complex CpRu(CO)(P(OPh)3)(η1-N-maleimidato) 3b is the most cytotoxic for HL-60/DR cells (IC50 = 104.35 µM). We found the genotoxic potential of complexes 2a and 3a only in HL-60 cells. These complexes also induced apoptosis in HL-60 cells. Docking studies showed that complexes 2a and CpRu(CO)(P(Fu)3)(η1-N-maleimidato) 2b have a small ability to degrade DNA, but they may cause a defect in DNA damage repair mechanisms leading to cell death. This hypothesis is corroborated with the results obtained in the plasmid relaxation assay in which ruthenium complexes bearing phosphine and phosphite ligands induce DNA breaks.

BET Proteins as Attractive Targets for Cancer Therapeutics.

Transcriptional dysregulation is a hallmark of cancer and can be an essential driver of cancer initiation and progression. Loss of transcriptional control can cause cancer cells to become dependent on certain regulators of gene expression. Bromodomain and extraterminal domain (BET) proteins are epigenetic readers that regulate the expression of multiple genes involved in carcinogenesis. BET inhibitors (BETis) disrupt BET protein binding to acetylated lysine residues of chromatin and suppress the transcription of various genes, including oncogenic transcription factors. Phase I and II clinical trials demonstrated BETis' potential as anticancer drugs against solid tumours and haematological malignancies; however, their clinical success was limited as monotherapies. Emerging treatment-associated toxicities, drug resistance and a lack of predictive biomarkers limited BETis' clinical progress. The preclinical evaluation demonstrated that BETis synergised with different classes of compounds, including DNA repair inhibitors, thus supporting further clinical development of BETis. The combination of BET and PARP inhibitors triggered synthetic lethality in cells with proficient homologous recombination. Mechanistic studies revealed that BETis targeted multiple essential homologous recombination pathway proteins, including RAD51, BRCA1 and CtIP. The exact mechanism of BETis' anticancer action remains poorly understood; nevertheless, these agents provide a novel approach to epigenome and transcriptome anticancer therapy.

SENP Proteases as Potential Targets for Cancer Therapy.

SUMOylation is a reversible post-translational modification (PTM) involving a covalent attachment of small ubiquitin-related modifier (SUMO) proteins to substrate proteins. SUMO-specific proteases (SENPs) are cysteine proteases with isopeptidase activity facilitating the de-conjugation of SUMO proteins and thus participating in maintaining the balance between the pools of SUMOylated and unSUMOylated proteins and in SUMO recycling. Several studies have reported that SENPs' aberrant expression is associated with the development and progression of cancer. In this review, we will discuss the role of SENPs in the pathogenesis of cancer, focusing on DNA repair and the cell cycle-cellular pathways malfunctioning in most cancer cells. The plausible role of SENPs in carcinogenesis resulted in the design and development of their inhibitors, including synthetic protein-based, peptide-based, and small molecular weight inhibitors, as well as naturally occurring compounds. Computational methods including virtual screening have been implemented to identify a number of lead structures in recent years. Some inhibitors suppressed the proliferation of prostate cancer cells in vitro and in vivo, confirming that SENPs are suitable targets for anti-cancer treatment. Further advances in the development of SENP-oriented inhibitors are anticipated toward SENP isoform-specific molecules with therapeutic potential.

PARP1-LSD1 functional interplay controls transcription of SOD2 that protects human pro-inflammatory macrophages from death under an oxidative condition.

The function of macrophages makes them vulnerable to several sources of stress and damage, and thus there is a considerable requirement for some form of resilient molecular defence. Differentiation of human macrophages and their further pro-inflammatory (M1) polarization with bacterial endotoxin is associated with increased transcription of PARP1 and SOD2. The latter gene responded immediately to LPS with high NFκB-dependent expression rate, and the resulting enzyme made M1 macrophages resistant to hydrogen peroxide-induced oxidative stress and associated cell death. LPS-induced recruitment of RELA to SOD2 promoter was accompanied by release of PARP1 and LSD1 from chromatin and increased H3K4 di- and tri-methylation. PARP1 dissociation from SOD2 promoter occurred at an early stage of SOD2 transcriptional activation. This event contributed to the termination of mRNA synthesis at a later stage of macrophage polarization by allowing LSD1 to rebind to the SOD2 promoter. LSD1 removed transcription-promoting methylation of H3K4 and led to displacement of RELA. Analysis of temporal changes at the SOD2 promoter indicated a direct mutual interdependence between PARP1, LSD1, H3K4 methylation and the ongoing SOD2 transcription, which correlated positively with both PARP1 abundance on the chromatin and dimethylation of H3K4, but negatively with LSD1 and chromatin compaction in LPS-treated macrophages. Deficiency of LSD1 activity and maintenance of PARP1 at the SOD2 promoter substantially upregulated SOD2 level, thereby further increasing resistance of M1 macrophages to hydrogen peroxide. Inhibitors of LSD1 and PARP1 poisons that capture the latter enzyme on the chromatin seem to be prosurvival molecular tools protecting polarized macrophages from certain pro-oxidative conditions.

NF-κB-Mediated Inflammation in the Pathogenesis of Intracranial Aneurysm and Subarachnoid Hemorrhage. Does Autophagy Play a Role?

The rupture of saccular intracranial aneurysms (IA) is the commonest cause of non-traumatic subarachnoid hemorrhage (SAH)—the most serious form of stroke with a high mortality rate. Aneurysm walls are usually characterized by an active inflammatory response, and NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) has been identified as the main transcription factor regulating the induction of inflammation-related genes in IA lesions. This transcription factor has also been related to IA rupture and resulting SAH. We and others have shown that autophagy interacts with inflammation in many diseases, but there is no information of such interplay in IA. Moreover, NF-κB, which is a pivotal factor controlling inflammation, is regulated by autophagy-related proteins, and autophagy is regulated by NF-κB signaling. It was also shown that autophagy mediates the normal functioning of vessels, so its disturbance can be associated with vessel-related disorders. Early brain injury, delayed brain injury, and associated cerebral vasospasm are among the most serious consequences of IA rupture and are associated with impaired function of the autophagy⁻lysosomal system. Further studies on the role of the interplay between autophagy and NF-κB-mediated inflammation in IA can help to better understand IA pathogenesis and to identify IA patients with an increased SAH risk.

Downregulation of PARP1 transcription by CDK4/6 inhibitors sensitizes human lung cancer cells to anticancer drug-induced death by impairing OGG1-dependent base excision repair.

Hallmarks of cancer cells include uncontrolled growth and rapid proliferation; thus, cyclin-dependent kinases are a therapeutic target for cancer treatment. Treating non-small lung cancer cells with sublethal concentrations of the CDK4/6 inhibitors, ribociclib (LEE011) and palbociclib (PD0332991), which are approved by the FDA for anticancer therapies, caused cell cycle arrest in the G1 phase and suppression of poly(ADP-ribose) polymerase 1 (PARP1) transcription by inducing recruitment of the RB1-E2F1-HDAC1-EZH2 repressive complex to the PARP1 promoter. Downregulation of PARP1 made cancer cells vulnerable to death triggered by the anticancer drugs (WP631 and etoposide) and H2O2. All agents brought about redox imbalance and DNA strand breaks. The lack of PARP1 and poly(ADP-ribosyl)ation impaired the 8-oxoguanine glycosylase (OGG1)-dependent base excision DNA repair pathway, which is critical for maintaining the viability of cells treated with CDK4/6 inhibitors during oxidative stress. Upon G1 arrest of PARP1 overexpressing cells, OGG1 formed an immunoprecipitable complex with PARP1. Similar to cells with downregulated PARP1 expression, inhibition of PARP1 or OGG1 in PARP1 overexpressing cells resulted in DNA damage and decreased viability. Thus, PARP1 and OGG1 act in the same regulatory pathway, and PARP1 activity is required for OGG1-mediated repair of oxidative DNA damage in G1-arrested cells. In conclusion, the action of CDK4/6 inhibitors is not limited to the inhibition of cell growth. CDK4/6 inhibitors also lead to accumulation of DNA damage by repressing PARP1 in oxidatively stressed cells. Thus, CDK4/6 inhibitors sensitize G1-arrested cells to anticancer drugs, since these cells require PARP1-OGG1 functional interaction for cell survival.

Autophagy regulates death of retinal pigment epithelium cells in age-related macular degeneration.

Age-related macular degeneration (AMD) is an eye disease underlined by the degradation of retinal pigment epithelium (RPE) cells, photoreceptors, and choriocapillares, but the exact mechanism of cell death in AMD is not completely clear. This mechanism is important for prevention of and therapeutic intervention in AMD, which is a hardly curable disease. Present reports suggest that both apoptosis and pyroptosis (cell death dependent on caspase-1) as well as necroptosis (regulated necrosis dependent on the proteins RIPK3 and MLKL, caspase-independent) can be involved in the AMD-related death of RPE cells. Autophagy, a cellular clearing system, plays an important role in AMD pathogenesis, and this role is closely associated with the activation of the NLRP3 inflammasome, a central event for advanced AMD. Autophagy can play a role in apoptosis, pyroptosis, and necroptosis, but its contribution to AMD-specific cell death is not completely clear. Autophagy can be involved in the regulation of proteins important for cellular antioxidative defense, including Nrf2, which can interact with p62/SQSTM, a protein essential for autophagy. As oxidative stress is implicated in AMD pathogenesis, autophagy can contribute to this disease by deregulation of cellular defense against the stress. However, these and other interactions do not explain the mechanisms of RPE cell death in AMD. In this review, we present basic mechanisms of autophagy and its involvement in AMD pathogenesis and try to show a regulatory role of autophagy in RPE cell death. This can result in considering the genes and proteins of autophagy as molecular targets in AMD prevention and therapy.

All-Trans Retinoic Acid Modulates DNA Damage Response and the Expression of the VEGF-A and MKI67 Genes in ARPE-19 Cells Subjected to Oxidative Stress.

Age-related macular degeneration (AMD) is characterized by the progressive degradation of photoreceptors and retinal pigment epithelium (RPE) cells. ARPE-19 is an RPE cell line established as an in vitro model for the study of AMD pathogenesis. Oxidative stress is an AMD pathogenesis factor that induces DNA damage. Thus, the oxidative stress-mediated DNA damage response (DDR) of ARPE-19 cells can be important in AMD pathogenesis. The metabolism of retinoids-which regulates cell proliferation, differentiation, and the visual cycle in the retina-was reported to be disturbed in AMD patients. In the present work, we studied the effect of all-trans retinoic acid (ATRA, a retinoid) on DDR in ARPE-19 cells subjected to oxidative stress. We observed that ATRA increased the level of reactive oxygen species (ROS), alkali-labile sites in DNA, DNA single-strand breaks, and cell death evoked by oxidative stress. ATRA did not modulate DNA repair or the distribution of cells in cell cycle in the response of ARPE-19 cells to oxidative stress. ATRA induced autophagy in the absence of oxidative stress, but had no effect on this process in the stress. ATRA induced over-expression of proliferation marker MKI67 and neovascularization marker VEGF-A. In conclusion, ATRA increased oxidative stress in ARPE-19 cells, resulting in more lesions to their DNA and cell death. Moreover, ATRA can modulate some properties of these cells, including neovascularization, which is associated with the exudative form of AMD. Therefore, ATRA can be important in the prevention, diagnosis, and therapy of AMD.

Inhibition of DNA methyltransferase or histone deacetylase protects retinal pigment epithelial cells from DNA damage induced by oxidative stress by the stimulation of antioxidant enzymes.

Epigenetic modifications influence DNA damage response (DDR). In this study we explored the role of DNA methylation and histone acetylation in DDR in cells challenged with acute or chronic oxidative stress. We used retinal pigment epithelial cells (ARPE-19), which natively are exposed to oxidative stress due to permanent exposure to light and high blood flow. We employed a DNA methyltransferase inhibitor - RG108 (RG), or a histone deacetylase inhibitor - valproic acid (VA). ARPE-19 cells were exposed to tert-butyl hydroperoxide, an acute oxidative stress inducer, or glucose oxidase, which slowly liberates low-doses of hydrogen peroxide in the presence of glucose, creating chronic conditions. VA and RG reduced level of intracellular reactive oxygen species and DNA damage in ARPE-19 cells in normal condition and in oxidative stress. This protective effect of VA and RG was associated with the up-regulated expression of antioxidant enzyme genes: CAT, GPx1, GPx4, SOD1 and SOD2. RG decreased the number of cells in G2/M checkpoint in response to chronic oxidative stress. Neither RG nor VA changed the DNA repair or apoptosis induced by oxidative stress. Therefore, certain epigenetic manipulations may protect ARPE-19 cells from detrimental effects of oxidative stress by modulation of antioxidative enzyme gene expression, which may be further explored in pharmacological studies on oxidative stress-related eye diseases.

Role of the Cell Cycle Re-Initiation in DNA Damage Response of Post-Mitotic Cells and Its Implication in the Pathogenesis of Neurodegenerative Diseases.

Neurodegenerative diseases are often associated with both normal and premature aging. Resumption of the cell cycle by neurons induced by DNA damage may lead to their apoptosis, which contributes to the degeneration of neuronal tissue. Cell cycle and DNA replication proteins are frequently found in patients with neurodegenerative diseases. Oxidative stress, which is considered to play an important role in aging and pathogenesis of many neurodegenerative diseases, can induce DNA damage and stimulate cell cycle re-entry by neuronal cells. DNA damage activates ataxia telangiectasia mutated (ATM), ataxia telangiectasia and Rad3-related (ATR), breast cancer 1 (BRCA1), E2F transcription factor 1 (E2F1), and other proteins that regulate the cell cycle, DNA damage repair, and apoptosis. Because the E2F complexes associate with histone-modifying enzymes, histone modifications, including histone acetylation and methylation, are required for cell cycle re-entry and may play a regulatory role in DNA repair or apoptosis. Aberrant cell cycle regulation has been shown to play a role in age-related macular degeneration (AMD) in which retinal cells are affected and in inclusion body myositis, which is characterized by muscle cell dysfunction. There is also evidence to suggest that cytostatic chemotherapy could decrease dementia in Alzheimer's disease and multiple myeloma, supporting the use of cell cycle inhibitors in the therapy of degenerative diseases.

Role of mitochondria in carcinogenesis.

Mitochondria play the central role in supplying cells with ATP and are also the major source of reactive oxygen species (ROS) - molecules of both regulatory and destructive nature. Dysfunction of mitochondrial metabolism and/or morphology have been frequently reported in human cancers. This dysfunction can be associated with mitochondrial DNA (mtDNA) damage, which may be changed into mutations in mtDNA coding sequences, or the displacement-loop region, changes in the mtDNA copy number or mtDNA microsatellite instability. All these features are frequently associated with human cancers. Mutations in mtDNA can disturb the functioning of the ROS-producing organelle and further affect the entire cell which may contribute to genomic instability typical for cancer cells. Although the association between some mtDNA mutations and cancer is well established, the causative relationship between these two features is largely unknown. A hint suggesting the driving role of mtDNA mutations in carcinogenesis comes from the observation of tumor promotion after mtDNA depletion. Mitochondria with damaged DNA may alter signaling of the mitochondrial apoptosis pathway promoting cancer cell survival and conferring resistance to anticancer drugs. This resistance may be underlined by mtDNA copy number depletion. Therefore, mitochondria are considered a promising target in anticancer therapy and several mitochondria-targeting drugs are in preclinical and clinical trials. Some other aspects of mitochondrial structure and functions, including morphology and redox potential, can also be associated with cancer transformation and constitute new anticancer targets. Recently, several studies have disclosed new mechanisms underlying the association between mitochondria and cancer, including the protection of mtDNA by telomerase, suggesting new approaches in mitochondria-oriented anti-cancer therapy.

Dexamethasone and 1,25-dihydroxyvitamin D3 reduce oxidative stress-related DNA damage in differentiating osteoblasts.

The process of osteoblast differentiation is regulated by several factors, including RUNX2. Recent reports suggest an involvement of RUNX2 in DNA damage response (DDR), which is important due to association of differentiation with oxidative stress. In the present work we explore the influence of two RUNX2 modifiers, dexamethasone (DEX) and 1,25-dihydroxyvitamin D3 (1,25-D3), in DDR in differentiating MC3T3-E1 preosteoblasts challenged by oxidative stress. The process of differentiation was associated with reactive oxygen species (ROS) production and tert-butyl hydroperoxide (TBH) reduced the rate of differentiation. The activity of alkaline phosphatase (ALP), a marker of the process of osteoblasts differentiation, increased in a time-dependent manner and TBH further increased this activity. This may indicate that additional oxidative stress, induced by TBH, may accelerate the differentiation process. The cells displayed changes in the sensitivity to TBH in the course of differentiation. DEX increased ALP activity, but 1,25-D3 had no effect on it. These results suggest that DEX might stimulate the process of preosteoblasts differentiation. Finally, we observed a protective effect of DEX and 1,25-D3 against DNA damage induced by TBH, except the day 24 of differentiation, when DEX increased the extent of TBH-induced DNA damage. We conclude that oxidative stress is associated with osteoblasts differentiation and induce DDR, which may be modulated by RUNX2-modifiers, DEX and 1,25-D3.

[Role of DNA methylation in colorectal cancer]. / Znaczenie metylacji DNA profilu epigenetycznego komórek jelita grubego w ich transformacji nowotworowej.

Epigenetic changes, including DNA methylation, influence the structure of chromatin, gene expression and genomic stability. It appears that the abnormal pattern of DNA methylation may be important in pathological conditions, including colorectal cancer. The most common pathway leading to this tumor is adenoma-carcinoma sequence. It was reported that during this process changes in the pattern of DNA methylation occurred, but the question whether these changes are the causes of neoplastic transformation of colorectal cancer or the consequences of pathological changes in the cancer cells is still open. Thus, changes in DNA methylation pattern may influence the pathogenesis of colorectal cancer but this hypothesis has not been confirmed experimentally and there is a need for research determining the relationship between changes in DNA methylation profile and colorectal cancer. By analyzing methylation of DNA sequences a molecular subgroup of this tumor has been distinguished. It is characterized by a high frequency of methylation of genes and it was denoted CpG islands methylator phenotype (CIMP). Changes in the pattern of DNA methylation are used as molecular markers for diagnosis and screening of colorectal cancer. A better understanding of changes in DNA methylation in colorectal cancer may help to facilitate prognosis and prediction of the disease and to improve its diagnosis.

Role of antioxidant enzymes and small molecular weight antioxidants in the pathogenesis of age-related macular degeneration (AMD).

Cells in aerobic condition are constantly exposed to reactive oxygen species (ROS), which may induce damage to biomolecules, including proteins, nucleic acids and lipids. In normal circumstances, the amount of ROS is counterbalanced by cellular antioxidant defence, with its main components-antioxidant enzymes, DNA repair and small molecular weight antioxidants. An imbalance between the production and neutralization of ROS by antioxidant defence is associated with oxidative stress, which plays an important role in the pathogenesis of many age-related and degenerative diseases, including age-related macular degeneration (AMD), affecting the macula-the central part of the retina. The retina is especially prone to oxidative stress due to high oxygen pressure and exposure to UV and blue light promoting ROS generation. Because oxidative stress has an established role in AMD pathogenesis, proper functioning of antioxidant defence may be crucial for the occurrence and progression of this disease. Antioxidant enzymes play a major role in ROS scavenging and changes of their expression or/and activity are reported to be associated with AMD. Therefore, the enzymes in the retina along with their genes may constitute a perspective target in AMD prevention and therapy.

The role of microRNA in metastatic colorectal cancer and its significance in cancer prognosis and treatment.

microRNAs (miRNAs) are small, non-coding RNA molecules that regulate gene expression by targeting specific mRNAs. microRNAs play a role in several physiological processes in the cell, including migration, proliferation, differentiation and apoptosis. Apart from their role in regular metabolism, abnormal profiles of miRNA expression accompany cancer transformation, including colorectal cancer (CRC) metastasis. microRNAs may play a role in each phase of CRC metastasis including angiogenesis, invasion, intravasation, circulation, extravasation and metastatic colonization. microRNA levels may serve as a predictive CRC marker, which was confirmed by the serum level of miR-29a targeting KLF4, a marker of cell stemness, and the plasma level of miR-221 down-regulating c-Kit, Stat5A and ETS1, which are signal transducers and transcription factor, respectively. In turn, the level of miR-143 in CRC cells decreasing the amount of MACC1 (metastasis-associated in colon cancer-1) and oncogenic KRAS protein, may be utilized as a prognostic marker. Also, single nucleotide polymorphisms of genes encoding miRNAs, including miR-423 and miR-608, which correlate with tumor recurrence, may be useful as diagnostic, prognostic and predictive indicators in CRC metastasis. Pre-miR-34a and pre-miR-199a decreased the level of Axl, a tyrosine-protein kinase receptor, so they can be considered as drugs in antimetastatic therapy. On the other hand, miR-222 targeting ADAM-17, a disintegrin and metalloproteinase, and miR-328 interacting with ABCG2, an ABC transporter, may overcome drug resistance of cancer cells. microRNAs may be considered in wide-range application to facilitate CRC metastasis diagnosis, prognosis, prediction and therapy, however, further clinical, epidemiological and in vitro studies should be conducted to verify their utility.