Molecular medicine and the development of cancer chemopreventive agents

Oxidative Drugs and microRNA: New Opportunities for Cancer Prevention

Despite the impressive progress of therapies in recent years, cancer still remains the second leading cause of death in developed countries [...].

MicroRNA in Implant Dentistry: From Basic Science to Clinical Application

Specific microRNA (miRNA) expression profiles have been reported to be predictive of specific clinical outcomes of dental implants and might be used as biomarkers in implant dentistry with diagnostic and prognostic purposes. The aim of the present narrative review was to summarize current knowledge regarding the use of miRNAs in implant dentistry. The authors attempted to identify all available evidence on the topic and critically appraise it in order to lay the foundation for the development of further research oriented towards the clinical application of miRNAs in implant dentistry.

Salivary Micro-RNA and Oral Squamous Cell Carcinoma: A Systematic Review

Oral squamous cell carcinoma (OSCC) is a widespread malignancy with high mortality. In particular, a delay in its diagnosis dramatically decreases the survival rate. The aim of this systematic review was to investigate and summarize clinical results in the literature, regarding the potential use of salivary microRNAs (miRNAs) as diagnostic and prognostic biomarkers for OSCC patients. Twelve papers were selected, including both case-control and cohort studies, and all of them detected significantly dysregulated miRNAs in OSCC patients compared to healthy controls. Based on our results, salivary miRNAs might provide a non-invasive and cost-effective method in the diagnosis of OSCC, and also to monitor more easily its evolution and therapeutic response and therefore aid in the establishment of specific therapeutic strategies.

Diagnostic potential of peri-implant crevicular fluid microRNA-21-3p and microRNA-150-5p and extracellular vesicles in peri-implant diseases

BACKGROUND

To explore the diagnostic usefulness of extracellular vesicles (EVs), and their subpopulations (micro-vesicles and exosomes), and microRNAs (miRNA-21-3p, miRNA-150-5p, and miRNA-26a-5p) in peri-implant crevicular fluid (PICF) of subjects with healthy, peri-implant mucositis and peri-implantitis implants.

METHODS

A total of 54 patients were enrolled into healthy, peri-implant mucositis, and peri-implantitis groups. PICF samples were collected, EVs subpopulations (MVs and Exo) were isolated and characterized by nanoparticle tracking analysis and transmission electron microscopy. The expression of miRNA-21-3p, miRNA-150-5p and miRNA-26a-5p was quantified by qRT-PCR. Logistic regression models and accuracy performance tests were estimated.

RESULTS

PICF samples show the presence of EVs delimited by a bi-layered membrane, in accordance with the morphology and size (< 200 nm). The concentration of PICF-EVs, micro-vesicles and exosomes was significantly increased in peri-implantitis implants compared to healthy implants (P = 0.023, P = 0.002, P = 0.036, respectively). miRNA-21-3p and miRNA-150-5p expression were significantly downregulated in patients with peri-implantitis in comparison with peri-implant mucositis sites (P = 0.011, P = 0.020, respectively). The reduced expression of miRNA-21-3p and miRNA-150-5p was associated with peri-implantitis diagnosis (OR:0.23, CI 0.08-0.66, P = 0.007 and OR:0.07, CI 0.01-0.78, P = 0.031, respectively). The model which included the miRNA-21-3p and miRNA-150-5p expression had a sensitivity of 93.3%, a specificity of 76.5%, a positive predictive value of 77.8%, and a negative predictive value of 92.9%. The positive and negative likelihood ratios were 3.97 and 0.09, respectively. The area under the receiver operating characteristics curve for the model was 0.84.

CONCLUSIONS

An increase concentration of EVs with a downregulation expression of miRNA-21-3p and miRNA-150-5p could be related with the peri-implantitis development.

Predicting Response to Neoadjuvant Therapy in Colorectal Cancer Patients the Role of Messenger-and Micro-RNA Profiling

Colorectal cancer patients' responses to neoadjuvant therapy undergo broad inter-individual variations. The aim of this systematic review is to identify a molecular signature that is predictive of colon cancer downstaging and/or downgrading after neoadjuvant therapy. Among the hundreds analysed in the available studies, only 19 messenger-RNAs (mRNAs) and six micro-RNAs (miRNAs) were differentially expressed in responders versus non-responders in two or more independent studies. Therefore, a mRNA/miRNA signature can be designed accordingly, with limitations caused by the retrospective nature of these studies, the heterogeneity in study designs and the downgrading/downstaging assessment criteria. This signature can be proposed to tailor neoadjuvant therapy regimens on an individual basis.

Prediction of Titanium Implant Success by Analysis of microRNA Expression in Peri-Implant Tissue. A 5-Year Follow-Up Study

The aim of the present study is to evaluate the expression of microRNA (miRNA) in peri-implant soft tissue and to correlate epigenetic information with the clinical outcomes of the implants up to the five-year follow-up. Seven patients have been rehabilitated with fixed screw-retained bridges each supported by implants. Peri-implant bone resorption and soft tissue health parameters have been recorded over time with a five-year follow-up. Mini-invasive samples of soft peri-implant tissue have been taken three months after implant insertion. miRNA have been extracted from cells of the soft tissue samples to evaluate gene-expression at the implant sites by microarray analysis. The epigenomic data obtained by microarray technology has been statistically analyzed by dedicated software and compared with measured clinical parameters. Specific miRNA expression profiles predictive of specific clinical outcomes were found. In particular, some specific miRNA signatures appeared to be “protective” from bone resorption despite the presence of plaque accumulation. miRNA may be predictors of dental implant clinical outcomes and may be used as biomarkers for diagnostic and prognostic purposes in the field of implant dentistry.

Inherent and toxicant-provoked reduction in DNA repair capacity: A key mechanism for personalized risk assessment, cancer prevention and intervention, and response to therapy

Genomic investigations reveal novel evidence which indicates that genetic predisposition and inherent drug response are key factors for development of cancer and for poor response to therapy. However, mechanisms for these outcomes and interactions with environmental factors have not been well-characterized. Therefore, cancer risk, prevention, intervention and prognosis determinations have still mainly been based on population, rather than on individualized, evaluations. The objective of this review was to demonstrate that a key mechanism which contributes to the determination is inherent and/or toxicant-provoked reduction in DNA repair capacity. In addition, functional and quantitative determination of DNA repair capacity on an individual basis would dramatically change the evaluation and management of health problems from a population to a personalized basis. In this review, justifications for the scenario were delineated. Topics to be presented include assays for detection of functional DNA repair deficiency, mechanisms for DNA repair defects, toxicant-perturbed DNA repair capacity, epigenetic mechanisms (methylation and miRNA expression) for alteration of DNA repair function, and bioinformatics approach to analyze large amount of genomic data. Information from these topics has recently been and will be used for better understanding of cancer causation and of response to therapeutic interventions. Consequently, innovative genomic- and mechanism-based evidence can be increasingly used to develop more precise cancer risk assessment, and target-specific and personalized medicine.

Early and late effects of aspirin and naproxen on microRNAs in the lung and blood of mice, either unexposed or exposed to cigarette smoke

We recently showed that nonsteroidal anti-inflammatory drugs (NSAIDs) are able to inhibit the lung tumors induced by cigarette smoke, either mainstream (MCS) or environmental (ECS), in female mice. We used subsets of mice to analyze the expression of 1135 microRNAs in both lung and blood serum, as related to the whole-body exposure to smoke and/or oral administration of either aspirin or naproxen. In a first study, we evaluated early microRNA alterations in A/J mice exposed to ECS for 10 weeks, starting at birth, and/or treated with NSAIDs for 6 weeks, starting after weaning. At that time, when no histopathological change were apparent, ECS caused a considerable downregulation of pulmonary microRNAs affecting both adaptive mechanisms and disease-related pathways. Aspirin and naproxen modulated, with intergender differences, the expression of microRNAs having a variety of functions, also including regulation of cyclooxygenases and inflammation. In a second study, we evaluated late microRNA alterations in Swiss H mice exposed to MCS during the first 4 months of life and treated with NSAIDs after weaning until 7.5 months of life, when tumors were detected in mouse lung. Modulation of pulmonary microRNAs by the two NSAIDs was correlated with their ability to prevent preneoplastic lesions (microadenomas) and adenomas in the lung. In both studies, exposure to smoke and/or treatment with NSAIDs also modulated microRNA profiles in the blood serum. However, their levels were poorly correlated with those of pulmonary microRNAs, presumably because circulating microRNAs reflect the contributions from multiple organs and not only from lung.

Regulation of oncogenic genes by MicroRNAs and pseudogenes in human lung cancer

Lung cancer is one of the most common mortal cancer types both for men and women. Several different biomarkers have been analyzed to reveal lung cancer prognosis pathways for developing efficient therapeutics and diagnostic agents. microRNAs (miRNAs) and pseudogenes are critical biomarkers in lung cancer and alteration of their expression levels has been identified in each step of lung cancer tumorigenesis. miRNAs and pseudogenes are crucial gene regulators in normal cells as well as in lung cancer cells, and they have both oncogenic and tumor-suppressive roles in lung cancer tumorigenesis. In this study, we have determined the relationship between lung cancer related oncogenes and miRNAs along with pseudogenes in lung cancer, and the results indicate their potential as biological markers for diagnostic and therapeutic purposes.

Microarray expression in peri-implant tissue next to different titanium implant surfaces predicts clinical outcomes: a split-mouth study

OBJECTIVES

This split-mouth study evaluated miRNA expression of tissues around implants with different surface treatments.

MATERIAL AND METHODS

Each patient of the sample (five men and five women) received two implants (one control and one test) into an edentulous quadrant to support fixed partial dentures. The control implants (Osseotite) had a dual acid-etched (DAE) surface in the apical portion and a machined coronal part, test implants (Full Osseotite, FOSS) were completely DAE. Machined healing abutments were placed on control implants and DAE abutments on test ones. All implants were assigned codes for blinding. Standardized periapical radiographs were taken at baseline, 2 and 6 months, and 1 year after surgery. Plaque index (PI), bleeding on probing (BOP), and probing depth (PD) were recorded at 3 and 6 weeks, and 2, 3, 6, and 12 months post-implant placement. After 3 months, a mini-invasive sample of soft tissue was collected from seven patients (four women and three men) for miRNA microarray analysis.

RESULTS

Control implants showed greater bone resorption (BR) and lower PI: this was not statistically significant. No statistically significant differences in BOP and PD appeared. miRNA modulated by implant surfaces as well as by other clinical conditions has been identified. miRNA microarray analysis revealed that: (i) implant sites with low PI and absence of BOP had a miRNA expression profile similar to those with plaque and absence of BOP; sites with high PI and high BOP had a different profile. (ii) Implant sites with BOP presented similar profiles independently from implant surface. (iii) Implant sites with high PI and normal BR differed from others for miRNA expression profile. (iv) Implant sites with normal BR despite high BOP differed from others. This profile resembled that of FOSS implants. (v) Implant surface affected BR; groups having similar BR clusterized differently according to the implant type.

CONCLUSIONS

DAE surfaces induced lower BR and more plaque accumulation: This did not affect the health of soft tissues. miRNA analysis indicated that soft tissue inflammation is more related to gene expression profile than to plaque or to implant surface. Specific miRNA profile can protect implant sites from bleeding and BR irrespective of plaque accumulation.

MicroRNA-Based Linkage between Aging and Cancer: from Epigenetics View Point

Ageing is a complex process and a broad spectrum of physical, psychological, and social changes over time. Accompanying diseases and disabilities, which can interfere with cancer treatment and recovery, occur in old ages. MicroRNAs (miRNAs) are a set of small non-coding RNAs, which have considerable roles in post-transcriptional regulation at gene expression level. In this review, we attempted to summarize the current knowledge of miRNAs functions in ageing, with mainly focuses on malignancies and all underlying genetic, molecular and epigenetics mechanisms. The evidences indicated the complex and dynamic nature of miRNA-based linkage of ageing and cancer at genomics and epigenomics levels which might be generally crucial for understanding the mechanisms of age-related cancer and ageing. Recently in the field of cancer and ageing, scientists claimed that uric acid can be used to regulate reactive oxygen species (ROS), leading to cancer and ageing prevention; these findings highlight the role of miRNA-based inhibition of the SLC2A9 antioxidant pathway in cancer, as a novel way to kill malignant cells, while a patient is fighting with cancer.

Resveratrol induces apoptosis through modulation of the Akt/FoxO3a/Bim pathway in HepG2 cells

Resveratrol is a polyphenolic compound found in wine, which is mainly produced by the grapevine and exerts chemopreventive effects against hepatocellular carcinoma. However, the underlying molecular mechanisms have remained to be fully elucidated. The present study assessed whether resveratrol-induced apoptosis was mediated via the activation of the forkhead box O3a (FoxO3a) transcription factor. It was demonstrated that resveratrol treatment induced apoptosis in HepG2 cells, and that this pro-apoptotic effect was accompanied with increases in the expression of apoptotic protein Bim. Following resveratrol treatment, Akt-mediated phosphorylation of FoxO3a was observed to be diminished in HepG2 cells. Furthermore, resveratrol enhanced the nuclear levels of FoxO3a and mediated neuronal death via Bim. The present study demonstrated that resveratrol induced apoptosis in HepG2 cells through activation of the transcription factor FoxO3a and increasing the expression of Bim protein.

Molecular damage and lung tumors in cigarette smoke-exposed mice

Cigarette smoke (CS) induces lung cancer through a multistep process that is now being depicted by molecular analyses. During the early phase (weeks), DNA damage occurs in nuclear and mitochondrial DNA, triggering adaptive responses activated by transient microRNA downregulation in the expression of defensive genes and proteins. During the intermediate phase (months), damaged cells are removed by apoptosis and the resulting cell loss is counteracted by a recruitment of stem cells that are highly sensitive to genotoxic damage. In parallel, microRNA downregulation becomes irreversible because of an accumulation of molecular damage in DICER. During the late phase (years), apoptosis efficacy is decreased by fragile histidine triad loss, while irreversible microRNA downregulation triggers the expression of mutated oncogenes, resulting in adenoma appearance. Furthermore, deletions occur in microRNA-encoding genes, causing carcinoma formation and uncontrolled growth. All reported pathogenic steps are required to obtain a fully developed lung cancer. This complex pathogenesis develops over a long period of time; therefore, it is difficult to induce cancer in short-living animals exposed to CS, whereas in humans there is a long latency from the start of smoke exposure to the onset of cancer.

Molecular fingerprints of environmental carcinogens in human cancer

Identification of specific molecular changes (fingerprints) is important to identify cancer etiology. Exploitable biomarkers are related to DNA, epigenetics, and proteins. DNA adducts are the turning point between environmental exposures and biological damage. DNA mutational fingerprints are induced by carcinogens in tumor suppressor and oncogenes. In an epigenetic domain, methylation changes occurs in specific genes for arsenic, benzene, chromium, and cigarette smoke. Alteration of specific microRNA has been reported for environmental carcinogens. Benzo(a)pyrene, cadmium, coal, and wood dust hits specific heat-shock proteins and metalloproteases. The multiple analysis of these biomarkers provides information on the carcinogenic mechanisms activated by exposure to environmental carcinogens.

Assay of lapatinib in murine models of cigarette smoke carcinogenesis

Lapatinib, a dual tyrosine kinase inhibitor targeting the epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 2 (HER-2), is prescribed for the treatment of patients with metastatic breast cancer overexpressing HER-2. Involvement of this drug in pulmonary carcinogenesis has been poorly investigated. We used murine models suitable to evaluate cigarette smoke-related molecular and histopathological alterations. A total of 481 Swiss H mice were used. The mice were exposed to mainstream cigarette smoke (MCS) during the first four months of life. After 10 weeks, MCS caused an elevation of bulky DNA adducts, oxidative DNA damage and an extensive downregulation of microRNAs in lung. After four months, an increase in micronucleus frequency was observed in peripheral blood erythrocytes. After 7.5 months, histopathological alterations were detected in the lung, also including benign tumors and malignant tumors, and in the urinary tract. A subchronic toxicity study assessed the non-toxic doses of lapatinib, administered daily with the diet after weaning. After 10 weeks, lapatinib significantly attenuated the MCS-related nucleotide changes and upregulated several low-intensity microRNAs in lung. The drug poorly affected the MCS systemic genotoxicity and had modest protective effects on MCS-induced preneoplastic lesions in lung and kidney, when administered under conditions that temporarily mimicked interventions either in current smokers or ex-smokers. On the other hand, it caused some toxicity to the liver. Thus, on the whole, lapatinib appears to have a low impact in the smoke-related lung carcinogenesis models used, especially in terms of tumorigenic response.

The effects of environmental chemical carcinogens on the microRNA machinery

The first evidence that microRNA expression is early altered by exposure to environmental chemical carcinogens in still healthy organisms was obtained for cigarette smoke. To date, the cumulative experimental data indicate that similar effects are caused by a variety of environmental carcinogens, including polycyclic aromatic hydrocarbons, nitropyrenes, endocrine disruptors, airborne mixtures, carcinogens in food and water, and carcinogenic drugs. Accordingly, the alteration of miRNA expression is a general mechanism that plays an important pathogenic role in linking exposure to environmental toxic agents with their pathological consequences, mainly including cancer development. This review summarizes the existing experimental evidence concerning the effects of chemical carcinogens on the microRNA machinery. For each carcinogen, the specific microRNA alteration signature, as detected in experimental studies, is reported. These data are useful for applying microRNA alterations as early biomarkers of biological effects in healthy organisms exposed to environmental carcinogens. However, microRNA alteration results in carcinogenesis only if accompanied by other molecular damages. As an example, microRNAs altered by chemical carcinogens often inhibits the expression of mutated oncogenes. The long-term exposure to chemical carcinogens causes irreversible suppression of microRNA expression thus allowing the transduction into proteins of mutated oncogenes. This review also analyzes the existing knowledge regarding the mechanisms by which environmental carcinogens alter microRNA expression. The underlying molecular mechanism involves p53-microRNA interconnection, microRNA adduct formation, and alterations of Dicer function. On the whole, reported findings provide evidence that microRNA analysis is a molecular toxicology tool that can elucidate the pathogenic mechanisms activated by environmental carcinogens.

Proteomic approaches in biomarker discovery: new perspectives in cancer diagnostics

Despite remarkable progress in proteomic methods, including improved detection limits and sensitivity, these methods have not yet been established in routine clinical practice. The main limitations, which prevent their integration into clinics, are high cost of equipment, the need for highly trained personnel, and last, but not least, the establishment of reliable and accurate protein biomarkers or panels of protein biomarkers for detection of neoplasms. Furthermore, the complexity and heterogeneity of most solid tumours present obstacles in the discovery of specific protein signatures, which could be used for early detection of cancers, for prediction of disease outcome, and for determining the response to specific therapies. However, cancer proteome, as the end-point of pathological processes that underlie cancer development and progression, could represent an important source for the discovery of new biomarkers and molecular targets for tailored therapies.

MicroRNA-let-7a promotes E2F-mediated cell proliferation and NFκB activation in vitro

Epigenetic factors, including altered microRNA (miRNA) expression, may contribute to aberrant immune cell function in systemic lupus erythematosus (SLE). MiRNA-let-7a (let-7a) has been shown to directly alter cell cycle progression and proinflammatory cytokine production. Due to the crucial role of let-7a in cell division and inflammation, we investigated let-7a-mediated proliferation and NFκB translocation in J774A.1 macrophages and MES 13 mesangial cells in vitro. In immune-stimulated cells transfected with let-7a, cell proliferation was significantly increased over time. There was a significant increase in the number of immune-stimulated cells in S and G2 phases. Immune-stimulated cells overexpressing let-7a had increased nuclear translocation of NFκB. Bioinformatical analysis revealed that the E2F family, critical regulators of the G1-S transition, has potential binding sites for let-7a in their mRNA transcripts. Let-7a overexpression significantly increased the expression of the cell cycle activator E2F2 and increased retinoblastoma protein (Rb) phosphorylation in immune-stimulated cells. The cell cycle inhibitor E2F5 was significantly decreased in let-7a-transfected cells that were immune-stimulated. Bioinformatical analysis revealed E2F2 and NFκB are transcription factors predicted to regulate the let-7a promoter. We analyzed transcriptional regulation of let-7a by real-time RT-PCR using chromatin immunoprecipitation with E2F2 and NFκB antibodies. There was an increase in E2F2 and NFκB binding in DNA enriched for the let-7a promoter in immune-stimulated cells. Silencing E2F2 or NFκB significantly decreased let-7a expression and IL-6 production in immune-stimulated cells. Taken together, our results suggest that overexpression of let-7a may contribute to hyperplasia and the proinflammatory response in SLE.

MicroRNA-145 downregulation associates with advanced tumor progression and poor prognosis in patients suffering osteosarcoma

PURPOSE

Microribonucleic acid (miRNA)-145 (miR-145) has been identified as a tumor suppressor in several types of human cancers. Especially, miR-145 expression has been found to be significantly decreased in osteosarcoma tissues, and enforced expression of this miRNA could inhibit invasion and angiopoiesis of osteosarcoma cells. However, its clinical significance in osteosarcoma is still unclear. Therefore, the aim of this study was to analyze the association of miR-145 expression with clinicopathologic features and prognosis in patients suffering osteosarcoma.

METHODS

miR-145 expression was detected by quantitative real-time reverse transcriptase polymerase chain reaction analysis using 166 pairs of osteosarcoma and noncancerous bone tissues. Then, the associations of miR-145 expression with clinicopathological factors or survival of patients suffering osteosarcoma were determined.

RESULTS

The expression levels of miR-145 in osteosarcoma tissues were significantly lower than those in corresponding noncancerous bone tissues (P < 0.0001). In addition, miR-145 downregulation more frequently occurred in osteosarcoma specimens with advanced clinical stage (P = 0.003) and positive distant metastasis (P = 0.008). Moreover, the univariate analysis demonstrated that osteosarcoma patients with low miR-145 expression had poorer overall (P = 0.003) and disease-free survival (P < 0.001). Furthermore, the multivariate analysis identified low miR-145 expression as an independent prognostic factor for both overall (P = 0.01) and disease-free survival (P = 0.008).

CONCLUSION

For the first time, the current data offer convincing evidence that the down-regulation of miR-145 may be associated with tumor aggressiveness and tumor metastasis of osteosarcoma, and that this miRNA may be an independent prognostic marker for osteosarcoma patients.

Mechanistic insights into the role of microRNAs in cancer: influence of nutrient crosstalk

A plethora of studies have described the disruption of key cellular regulatory mechanisms involving non-coding RNAs, specifically microRNAs (miRNA) from the let-7 family, the miR-17 family, miR-21, miR-143, and the miR-200 family, which contribute to aberrant signaling and tumor formation. Certain environmental factors, such as bioactive dietary agents, e.g., folate, curcumin, polyunsaturated fatty acids, are also thought to impact the progression and severity of cancer. In terms of the chemoprotective mechanisms of action, these bioactive dietary agents appear to act, in part, by modulating tissue levels of miR-16, miR-17 family, miR-26b, miR-106b, and miR-200 family miRNAs and their target genes. However, the mechanisms of nutrient action are not yet fully understood. Therefore, additional characterization of the putative underlying mechanisms is needed to further our understanding of the biology, early diagnosis, prevention, and the treatment of cancer. For the purpose of elucidating the epigenetic landscape of cancer, this review will summarize the key findings from recent studies detailing the effect of bioactive dietary agents on miRNA regulation in cancer.

An emerging role for microRNAs in NF1 tumorigenesis

MicroRNAs (miRNAs) are a class of non-coding RNA, which have recently been shown to have a wide variety of regulatory functions in relation to gene expression. Since their identification nearly 20 years ago, miRNAs have been found to play an important role in cancer, including in neurofibromatosis type 1 (NF1)-associated tumours. NF1 is the most commonly inherited tumour predisposition syndrome and can lead to malignancy via the development of malignant peripheral nerve sheath tumours (MPNSTs). Although the mechanisms by which benign neurofibromas develop into MPNSTs still remain to be elucidated, it is becoming increasingly clear that miRNAs play a key role in this process and have the potential to be used as both diagnostic and prognostic markers of tumorigenesis.

Smoke-induced microRNA and related proteome alterations. Modulation by chemopreventive agents

Dysregulation of microRNAs (miRNAs) has important consequences on gene and protein expression since a single miRNA targets a number of genes simultaneously. This article provides a review of published data and ongoing studies regarding the effects of cigarette smoke (CS), either mainstream (MCS) or environmental (ECS), on the expression of miRNAs and related proteins. The results generated in mice, rats, and humans provided evidence that exposure to CS results in an intense dysregulation of miRNA expression in the respiratory tract, which is mainly oriented in the sense of downregulation. In parallel, there was an upregulation of proteins targeted by the downregulated miRNAs. These trends reflect an attempt to defend the respiratory tract by means of antioxidant mechanisms, detoxification of carcinogens, DNA repair, anti-inflammatory pathways, apoptosis, etc. However, a long-lasting exposure to CS causes irreversible miRNA alterations that activate carcinogenic mechanisms, such as modulation of oncogenes and oncosuppressor genes, cell proliferation, recruitment of undifferentiated stem cells, inflammation, inhibition of intercellular communications, angiogenesis, invasion, and metastasis. The miRNA alterations induced by CS in the lung of mice and rats are similar to those observed in the human respiratory tract. Since a number of miRNAs that are modulated by CS and/or chemopreventive agents are subjected to single nucleotide polymorphisms in humans, they can be evaluated according to toxicogenomic/pharmacogenomics approaches. A variety of cancer chemopreventive agents tested in our laboratory modulated both baseline and CS-related miRNA and proteome alterations, thus contributing to evaluate both safety and efficacy of dietary and pharmacological agents.