MicroRNA-148a promotes apoptosis and suppresses growth of breast cancer cells by targeting B-cell lymphoma 2

miRNAs that regulate apoptosis in breast cancer and cervical cancer

In today's world, one of the main problems is cancer, which still has a long way to go to cure it, and it brings a lot of financial and emotional costs to the people of society and governments. Breast cancer (BC) and cervical cancer (CC), two of the most common cancers, are caused by several genetic and environmental factors in women. These two cancers' involvement rate is higher than other cancers in women. microRNAs (miRNAs) are non-coding RNA molecules with a length of 18 to 24 nucleotides, which play an important role in post-translational changes. miRNAs themselves are divided into two categories, oncomiRs and tumor suppressors. OncomiRs have a part in tumor expansion and tumor suppressors prevent tumor development and progress. miRNAs can control cellular processes by regulating various pathways including autophagy, apoptosis, and signaling. Apoptosis is a type of programmed cell death that includes intrinsic and extrinsic pathways and is different from other cell death pathways such as necrosis and ferroptosis. Apoptosis controls the growth, differentiation, and death of cells by regulating the death of damaged and old cells, and since miRNAs are one of the factors that regulate apoptosis, and divided into two categories: pro-apoptotic and anti-apoptotic. We decided in this study to investigate the relationship between miRNAs and apoptosis in the most common women's cancers, BC and CC.

Mapping the function of MicroRNAs as a critical regulator of tumor-immune cell communication in breast cancer and potential treatment strategies

Among women, breast cancer ranks as the most prevalent form of cancer, and the presence of metastases significantly reduces prognosis and diminishes overall survival rates. Gaining insights into the biological mechanisms governing the conversion of cancer cells, their subsequent spread to other areas of the body, and the immune system's monitoring of tumor growth will contribute to the advancement of more efficient and targeted therapies. MicroRNAs (miRNAs) play a critical role in the interaction between tumor cells and immune cells, facilitating tumor cells' evasion of the immune system and promoting cancer progression. Additionally, miRNAs also influence metastasis formation, including the establishment of metastatic sites and the transformation of tumor cells into migratory phenotypes. Specifically, dysregulated expression of these genes has been associated with abnormal expression of oncogenes and tumor suppressor genes, thereby facilitating tumor development. This study aims to provide a concise overview of the significance and function of miRNAs in breast cancer, focusing on their involvement as tumor suppressors in the antitumor immune response and as oncogenes in metastasis formation. Furthermore, miRNAs hold tremendous potential as targets for gene therapy due to their ability to modulate specific pathways that can either promote or suppress carcinogenesis. This perspective highlights the latest strategies developed for miRNA-based therapies.

The role of epigenetic modifications in drug resistance and treatment of breast cancer

Background

Breast cancer is defined as a biological and molecular heterogeneous disorder that originates from breast cells. Genetic predisposition is the most important factor giving rise to this malignancy. The most notable mutations in breast cancer occur in the BRCA1 and BRCA2 genes. Owing to disease heterogeneity, lack of therapeutic target, anti-cancer drug resistance, residual disease, and recurrence, researchers are faced with challenges in developing strategies to treat patients with breast cancer.

Results

It has recently been reported that epigenetic processes such as DNA methylation and histone modification, as well as microRNAs (miRNAs), have potently contributed to the pathophysiology, diagnosis, and treatment of breast cancer. These observations have persuaded researchers to move their therapeutic approaches beyond the genetic framework toward the epigenetic concept.

Conclusion

Herein we discuss the molecular and epigenetic mechanisms underlying breast cancer progression and resistance as well as various aspects of epigenetic-based therapies as monotherapy and combined with immunotherapy.

miRNA-148a and miRNA-30c expressions as potential biomarkers in breast cancer patients

Background

Breast cancer is an extensively identified malignant tumor and is a prime cause of cancer mortalities in females. It has been shown that alteration of miRNAs expression (up or down regulation) can affect the initiation and progression of many malignancies. We aimed to evaluate the role of circulating miRNA-148a and miRNA-30c in female patients with breast cancer and estimate their usage as potential biomarkers in the diagnosis, prognosis and survival of breast cancer.

Methods

This study included 75 breast cancer female patients.They were compared with 55 apparently healthy female subjects. miRNAs expression analysis was assessed via real-time PCR.

Results

To discriminate breast cancer patients from controls, miR-30c showed the best performance at a cut off value of ≤20.6 (AUC = 0.998, 97.33% sensitivity, 96.36% specificity, p < 0.001), followed by miR-148a (AUC = 0.995, 94.67% sensitivity, 90.91% specificity, p < 0.001 at a cut off value of ≤0.1), CA 15-3 (AUC = 0.930, 88.0% sensitivity, 81.82% specificity, p < 0.001 at a cut off value of >21.3), and finally CEA (AUC = 0.751, 70.67% sensitivity, 63.64% specificity, p < 0.001 at a cut off value of >2.5).

Conclusion

miRNA-148a and miRNA-30c expressions were down regulated in female patients with breast cancer and might be considered as potential blood biomarkers. Both also might have rule in disease treatment and selection of therapeutic targets. Future studies are needed to improve their role in predicting response to treatment and prognosis.

Regulatory MicroRNAs in T2DM and Breast Cancer

MicroRNAs orchestrate the tight regulation of numerous cellular processes and the deregulation in their activities has been implicated in many diseases, including diabetes and cancer. There is an increasing amount of epidemiological evidence associating diabetes, particularly type 2 diabetes mellitus, to an elevated risk of various cancer types, including breast cancer. However, little is yet known about the underlying molecular mechanisms and even less about the role miRNAs play in driving the tumorigenic potential of the cell signaling underlying diabetes pathogenesis. This article reviews the role of miRNA in bridging the diabetes–breast cancer association by discussing specific miRNAs that are implicated in diabetes and breast cancer and highlighting the overlap between the disease-specific regulatory miRNA networks to identify a 20-miRNA signature that is common to both diseases. Potential therapeutic targeting of these molecular players may help to alleviate the socioeconomic burden on public health that is imposed by the type 2 diabetes mellitus (T2DM)–breast cancer association.

Crosstalk between miRNAs and signaling pathways involved in pancreatic cancer and pancreatic ductal adenocarcinoma

Pancreatic cancer (PC) is the seventh leading cause of cancer-related deaths worldwide with 5-year survival rates below 8%. Most patients with PC and pancreatic ductal adenocarcinoma (PDAC) die after relapse and cancer progression as well as resistance to treatment. Pancreatic tumors contain a high desmoplastic stroma that forms a rigid mass and has a potential role in tumor growth and metastasis. PC initiates from intraepithelial neoplasia lesions leading to invasive cancer through various pathways. These lesions harbor particular changes in signaling pathways involved in the tumorigenesis process. These events affect both the epithelial cells, including the tumor and the surrounding stroma, and eventually lead to the formation of complex signaling networks. Genetic studies of PC have revealed common molecular features such as the presence of mutations in KRAS gene in more than 90% of patients, as well as the inactivation or deletion mutations of some tumor suppressor genes including TP53, CDKN2A, and SMAD4. In recent years, studies have also identified different roles of microRNAs in PC pathogenesis as well as their importance in PC diagnosis and treatment, and their involvement in various signaling pathways. In this study, we discussed the most common pathways involved in PC and PDAC as well as their role in tumorigenesis and progression. Furthermore, the miRNAs participating in the regulation of these signaling pathways in PC progression are summarized in this study. Therefore, understanding more about pathways involved in PC can help with the development of new and effective therapies in the future.

The role of microRNAs in cell death pathways

MicroRNAs (miRNAs) are a class of noncoding RNAs that negatively regulate target messenger RNAs. In multicellular eukaryotes, numerous miRNAs perform basic cellular functions, including cell proliferation, differentiation, and death. Abnormal expression of miRNAs weakens or modifies various apoptosis pathways, leading to the development of human cancer. Cell death occurs in an active manner that maintains tissue homeostasis and eliminates potentially harmful cells through regulated cell death processes, including apoptosis, autophagic cell death, and necroptosis. In this review, we discuss the involvement of miRNAs in regulating cell death pathways in cancers and the potential therapeutic functions of miRNAs in cancer treatment.

gga-miR-148a-5p-Targeting PDPK1 Inhibits Proliferation and Cell Cycle Progression of Avain Leukosis Virus Subgroup J (ALV-J)-Infected Cells

Avian leukosis virus subgroup J disease (ALV-J) is a contagious and immunosuppressive avian disease caused by ALV-J virus. Although miRNA participate in various biological processes of tumors, little is known about the potential role of miRNA in ALV-J. Our previous miRNA and RNA sequencing data showed that the expression of gga-miR-148a-5p was significantly different in ALV-J-infected chicken spleens compared with non-infected chickens. The aim of this study was to investigate the functional roles of gga-miR-148a-5p and identify downstream targets regulated by gga-miR-148a-5p in ALV-J-infected chickens. We found that the expression of gga-miR-148a-5p was significantly downregulated during ALV-J infection of chicken embryo fibroblasts (CEF). Dual luciferase reporter assays demonstrated that PDPK1 is a direct target gene of gga-miR-148a-5p. In vitro, overexpression of gga-miR-148a-5p significantly promoted ALV-J-infected CEF cell proliferation, included cell cycle, whereas inhibition of gga-miR-148a-5p had an opposite effect. Inhibition of PDPK1 promoted the proliferation of ALV-J-infected cells but had no effect on the activity of NF-κB. Together, these results suggested that gga-miR-148a-5p targets PDPK1 to inhibit the proliferation and cell cycle of ALV-J-infected CEF cells. Our study provides a new understanding for the tumor mechanism of ALV-J infection.

miRNA-mediated alteration of sulfatase modifying factor 1 expression using self-assembled branched DNA nanostructures

Sulfatase enzymes catalyze sulfate ester hydrolysis, thus deficiencies of sulfatases lead to the accumulation of biomolecules resulting in several disorders. One of the important sulfatases is estrone sulfatase that converts inactive estrone sulfate to active estradiol. Posttranslational modification of highly conserved cysteine residue leads to unique formylglycine in the active site of sulfatases being critical for its catalytic activity. The essential factor responsible for this modification of sulfatase is Sulfatase-Modifying Factor 1 (SUMF1). The role of estrone sulfatase is well evident in breast cancer progression. However, the function and regulation of SUMF1 in cancer are not studied. In the present study, for the first time, we have assessed the expression of SUMF1 in breast cancer and report the oncogenic behavior upon overexpression of SUMF1. Although increased expression or activity of SUMF1 is anticipated based on its function, the expression of SUMF1 was found to be reduced in breast cancer cells at both mRNA and protein levels. An estrogen receptor (ER) dependent expression of SUMF1 was observed and higher SUMF1 expression is associated with improved breast cancer patient survival in ER-positive cases. However, high SUMF1 expression leads to reduced median survival in ER-negative breast cancer patients. Putative binding sites for miRNAs-106b-5p, 128-3p and 148b-3p were found at 3′-UTR of SUMF1. Since self-assembled branched DNA (bDNA) structures have emerged as a highly efficient strategy for targeting multiple miRNAs simultaneously, we studied the alteration in SUMF1 expression using bDNA nanostructures with a complementary sequence to miRNAs. The findings suggest the involvement of co-regulators and repressors in miRNA-mediated SUMF1 expression in breast cancer cells and reveal the therapeutic potential of SUMF1 in endocrine-related malignancies.

Reduced expression of SUMF1 was evidenced in MCF-7 cells transfected with antimiR-bDNA. Expression of miRNA-106 and 148 have positive correlation with the expression of SUMF1. miRNA-106 and 148 blocks the repressor protein controls SUMF-1 expression.

The role of tumor suppressor short non-coding RNAs on breast cancer

Characterized by remarkable levels of aggression and malignancy, BC remains one of the leading causes of death in females world wide. Accordingly, significant efforts have been made to develop early diagnostic tools, increase treatment efficacy, and improve patient prognosis. Hopefully, many of the molecular mechanisms underlying BC have been detected and show promising targeting potential. In particular, short and long non-coding RNAs (ncRNAs) are a class of endogenous BC controllers and include a number of different species including microRNAs, Piwi-interacting RNAs, small nucleolar RNA, short interfering RNAs, and tRNA-derivatives. In this review, we discuss the tumor suppressing roles of ncRNAs in the context of BC, and the mechanisms by which ncRNAs target tumor hallmarks, including apoptosis, proliferation, invasion, metastasis, epithelial-mesenchymal transition, angiogenesis, and cell cycle progression, in addition to their diagnostic and prognostic significance in cancer treatment.

LINC00346 regulates glycolysis by modulation of glucose transporter 1 in breast cancer cells

Most cancer cells preferentially metabolize glucose by glycolysis rather than oxidative phosphorylation to proliferate efficiently. LncRNAs have been proposed as crucial regulators in pathophysiological processes including cell growth, apoptosis and glucose metabolism. However, little is known regarding the specific role of LINC00346 in regulating glucose metabolism in breast cancer. LINC00346 and miR-148a/b expression in breast cancer cells was detected by qRT-PCR. The relationships between LINC00346, glucose transporter 1 (GLUT1) and miR-148a/b in breast cancer cells were explored by luciferase reporter assay. Cell proliferation and apoptosis were evaluated by CCK-8 and flow cytometry analysis, respectively. Glycolysis was detected by measuring the glucose uptake and lactate production. Results showed that LINC00346 was over-expressed while miR-148a/b was low-expressed in breast cancer cells. miR-148a/b were direct targets of LINC00346 in breast cancer cells. LINC00346 knockdown inhibited cell proliferation and glycolysis, and induced apoptosis by upregulating miR-148a/b in breast cancer cells. Furthermore, we found that LINC00346 knockdown repressed GLUT1 expression in breast cancer cells by upregulating miR-148a/b. In conclusion, LINC00346 knockdown suppressed breast cancer cell glycolysis by upregulating miR-148a/b and repressing GLUT1 expression.

miR-185-5p response to usnic acid suppresses proliferation and regulating apoptosis in breast cancer cell by targeting Bcl2

BACKGROUND

Breast cancer is the most common cancer types among women. Recent researches have focused on determining the efficiency of alternative molecules and miRNAs in breast cancer treatment. The aim of this study was to determine the effect of usnic acid response-miR-185-5p on proliferation in the breast cancer cell and to determine its relationship with apoptosis pathway.

METHODS

The cell proliferation and cell apoptosis rate were significantly increased following the ectopic expression of miR-185-5p in BT-474 cells. Furthermore, the results of cell cycle assay performed by flow cytometry revealed that the transfection with miR-185-5p induced G1/S phase arrest. The apoptosis-related genes expression analysis was performed by qRT-PCR and the direct target of miR-185-5p in BT-474 cells was identified by western blot and luciferase reporter assay.

RESULTS

Our data showed that miR-185-5p can cause significant changes in apoptosis-related genes expression levels, suggesting that cell proliferation was suppressed by miR-185-5p via inducing apoptosis in breast cancer cells. According to western blot results, miR-185-5p lead to decrease BCL2 protein level in BT-474 cells and direct target of miR-185-5p was identified as BCL by luciferase reporter assay.

CONCLUSION

This study revealed that miR-185-5p may be an effective agent in the treatment of breast cancer.

Anticancer properties and mechanism of action of the quassinoid ailanthone

Ailanthone (AIT) is a quassinoid natural product isolated from the worldwide-distributed plant Ailanthus altissima. The drug displays multiple pharmacological properties, in particular significant antitumor effects against a variety of cancer cell lines in vitro. Potent in vivo activities have been evidenced in mice bearing hepatocellular carcinoma, nonsmall cell lung cancer and castration-resistant prostate cancer. This review focusses on the mechanism of action of AIT, notably to highlight the capacity of the drug to activate DNA damage responses, to inhibit the Hsp90 co-chaperone p23 and to modulate the expression of several microRNA. The interconnexion between these effects is discussed. The unique capacity of AIT to downregulate oncogenic miR-21 and to upregulate the tumor suppressor miRNAs miR-126, miR-148a, miR-195, and miR-449a is presented. AIT exploits several microRNAs to exert its anticancer effects in distinct tumor types. AIT is one of the rare antitumor natural products that binds to and strongly inhibits cochaperone p23, opening interesting perspectives to treat cancers. However, the toxicity profile of the molecule may limit its development as an anticancer drug, unless it can be properly formulated to prevent AIT-induced gastro-intestinal damages in particular. The antitumor properties of AIT and analogs are underlined, with the aim to encourage further pharmacological studies with this underexplored natural product and related quassinoids. HIGHLIGHTS: Ailanthone (AIT) is an anticancer quassinoid isolated from Ailanthus altissima It inhibits proliferation and induces cell death of many cancer cell types The drug activates DNA damage response and targets p23 cochaperone Up or downregulation of several microRNA by AIT contributes to the anticancer activity Analogs or specific formulations must be developed to prevent the toxicity of AIT.

The Regulatory Role of MicroRNAs in Breast Cancer

MicroRNAs (miRNAs) are small non-coding RNA molecules which function as critical post-transcriptional gene regulators of various biological functions. Generally, miRNAs negatively regulate gene expression by binding to their selective messenger RNAs (mRNAs), thereby leading to either mRNA degradation or translational repression, depending on the degree of complementarity with target mRNA sequences. Aberrant expression of these miRNAs has been linked etiologically with various human diseases including breast cancer. Different cellular pathways of breast cancer development such as cell proliferation, apoptotic response, metastasis, cancer recurrence and chemoresistance are regulated by either the oncogenic miRNA (oncomiR) or tumor suppressor miRNA (tsmiR). In this review, we highlight the current state of research into miRNA involved in breast cancer, with particular attention to articles published between the years 2000 to 2019, using detailed searches of the databases PubMed, Google Scholar, and Scopus. The post-transcriptional gene regulatory roles of various dysregulated miRNAs in breast cancer and their potential as therapeutic targets are also discussed.

miR-148a inhibits cell proliferation and migration through targeting ErbB3 in colorectal cancer

Colorectal cancer is a common gastrointestinal cancer ranking in third place of all cancers. Downregulation of miR-148a has been observed in many tumors, and miR-148a was found to be an oncogene in colorectal cancer. The aim of our study was to investigate the molecular mechanisms by which miR-148a and ErbB3 proliferate and migrate in colorectal cancer. The expression of miR-148a and ErbB3 were measured by western blot analysis and RT-qPCR. MTT and transwell assays were performed to analyze the proliferative and migratory abilities. The dual luciferase reporter assay was employed to confirm miR-148a regulated the expression of ErbB3 in colorectal cancer. It was discovered that miR-148a was overexpressed while ErbB3 expression was low in colorectal cancer, and the mRNA level of miR-148a had a negative correlation with the expression of ErbB3. Upregulation of miR-148a suppressed the proliferation and migration in colorectal cancer cells. Furthermore, ErbB3 was identified as a direct target of miR-148a, which suppressed the proliferation and migration through directly binding to the 3′UTR of ErbB3 mRNA. This study established that miR-148a inhibited the proliferative and migratory abilities through mediating the expression of ErbB3. The newly identified miR-148a/ErbB3 axis provides novel insight into the pathogenesis of colorectal cancer, and represents a potential target for treatment of colorectal cancer.

MicroRNA-181c Suppresses the Biological Progression of Osteosarcoma via Targeting SMAD7 and Regulating Transforming Growth Factor-β (TGF-β) Signaling Pathway

Background

Osteosarcoma is a primary bone aggressive cancer, affecting adolescents worldwide. Increasing evidence suggests that dysfunction of microRNAs (miRNAs) plays a pivotal role in malignancies. The aim of this study was to evaluate the potential functions of miR-181c and verifying its regulatory effects on SMAD7 in osteosarcoma.

Material/Methods

The expressions of miR-181c and SMAD7 in osteosarcoma were detected by quantitative real-time polymerase chain reaction (qRT-PCR). Cell proliferation, invasion and migration abilities were assessed using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) and Transwell assay. Bioinformatics analysis and luciferase reporter assay were used to explore the interaction between miR-181c and SMAD7. Western blot was performed to determine the functions of miR-181c on osteosarcoma cell epithelial-to-mesenchymal transition (EMT) and transforming growth factor-β (TGF-β) signaling pathway.

Results

Decreased expression levels of miR-181c and SMAD7 were identified in osteosarcoma using qRT-PCR. The downregulated miR-181c and SMAD7 expressions indicated poor prognosis of osteosarcoma patients. Moreover, miR-181c overexpression prominently repressed osteosarcoma cell proliferation, invasion, and migration abilities via modulating EMT and TGF-β signaling pathway. SMAD7 functioned as an important target for miR-181c in osteosarcoma cells. Furthermore, upregulation of miR-181c dramatically suppressed osteosarcoma tumorigenesis in vivo.

Conclusions

These findings indicated that miR-181c suppressed osteosarcoma progression, providing new insight into the pathogenesis and representing a potential therapeutic target for osteosarcoma.

Comparative analysis of milk microRNA in the therian lineage highlights the evolution of lactation

Milk is a complex secretion that has an important role in mammalian reproduction. It is only recently that sequencing technologies have allowed the identification and quantification of microRNA (miRNA) in milk of a growing number of mammalian species. This provides a novel window on the study of the evolution and functionality of milk through the comparative analysis of milk miRNA content. Here, milk miRNA sequencing data from five species (one marsupial (tammar wallaby) and four eutherians (human, mouse, cow and pig)) have been retrieved from public depositories and integrated in order to perform a comparison of milk miRNA profiles. The study shows that milk miRNA composition varies widely between species, except for a few miRNAs that are ubiquitously expressed in the milk of all mammals and indicates that milk miRNA secretion has broadly evolved during mammalian evolution. The putative functions of the most abundant milk miRNAs are also discussed.

Exosomes of pasteurized milk: potential pathogens of Western diseases

Milk consumption is a hallmark of western diet. According to common believes, milk consumption has beneficial effects for human health. Pasteurization of cow's milk protects thermolabile vitamins and other organic compounds including bioactive and bioavailable exosomes and extracellular vesicles in the range of 40-120 nm, which are pivotal mediators of cell communication via systemic transfer of specific micro-ribonucleic acids, mRNAs and regulatory proteins such as transforming growth factor-β. There is compelling evidence that human and bovine milk exosomes play a crucial role for adequate metabolic and immunological programming of the newborn infant at the beginning of extrauterine life. Milk exosomes assist in executing an anabolic, growth-promoting and immunological program confined to the postnatal period in all mammals. However, epidemiological and translational evidence presented in this review indicates that continuous exposure of humans to exosomes of pasteurized milk may confer a substantial risk for the development of chronic diseases of civilization including obesity, type 2 diabetes mellitus, osteoporosis, common cancers (prostate, breast, liver, B-cells) as well as Parkinson's disease. Exosomes of pasteurized milk may represent new pathogens that should not reach the human food chain.

Targeting of GIT1 by miR-149* in breast cancer suppresses cell proliferation and metastasis in vitro and tumor growth in vivo

Breast cancer remains a major cause of cancer-related death in women worldwide. Dysregulation of microRNAs (miRNAs) is involved in the initiation and progression of breast cancer. Moreover, it was found that GIT1 was widely involved in the development of many human cancers. Herein, we aimed to investigate the expression changes of miR-149* and GIT1 and the functional effects of miR-149*/GIT1 link in breast cancer. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and Western blot (WB) were used to examine the expression levels of miR-149* and GIT1. Dual luciferase reporter assay was utilized to confirm the target interaction between miR-149* and GIT1. The biological functions, including cell proliferation, invasion, and migration, of miR-149* and GIT1 were determined by MTT assay and Transwell assays, respectively. Eventually, the tumor xenograft model in nude mice injected with stable transfected MDA-MB-231 cells was established to verify the effects of miR-149* and GIT1 on tumor growth. Our results showed that miR-149* expression was decreased, whereas GIT1 expression was increased in clinical samples of breast cancer. Based on the inverse expression trend between miR-149* and GIT1, we further demonstrated that miR-149* indeed directly targets GIT1. Subsequently, it was observed that inhibition of miR-149* significantly promoted cell proliferation, invasion, and migration, but the ability of cell proliferation, invasion, and migration was obviously declined after silencing of GIT1 in MDA-MB-231 cells transfected with miR-149* mimic and/or si-GIT1. Finally, it was also found that elevated miR-149* decelerated the tumor growth, while restored GIT1 accelerated the tumor growth in nude mice after 35 days of tumor xenograft. Collectively, these findings concluded that miR-149* might exert a tumor suppressive role in breast cancer by targeting GIT1.

Cancer Hallmarks and MicroRNAs: The Therapeutic Connection

Human cancers are characterized by a number of hallmarks, including sustained proliferative signaling, evasion of growth suppressors, activated invasion and metastasis, replicative immortality, angiogenesis, resistance to cell death, and evasion of immune destruction. As microRNAs (miRNAs) are deregulated in virtually all human cancers, they show involvement in each of the cancer hallmarks as well. In this chapter, we describe the involvement of miRNAs in cancer from a cancer hallmarks and targeted therapeutics point of view. As no miRNA-based cancer therapeutics are available to date, and the only clinical trial on miRNA-based cancer therapeutics (MRX34) was terminated prematurely due to serious adverse events, we are focusing on protein-coding miRNA targets for which targeted therapeutics in oncology are already approved by the FDA. For each of the cancer hallmarks, we selected major protein-coding players and describe the miRNAs that target them.