Targeted Lipid Nanoemulsions Encapsulating Epigenetic Drugs Exhibit Selective Cytotoxicity on CDH1–/FOXM1+ Triple Negative Breast Cancer Cells

Targeting the epigenome with advanced delivery strategies for epigenetic modulators

Epigenetics mechanisms play a significant role in human diseases by altering DNA methylation status, chromatin structure, and/or modifying histone proteins. By modulating the epigenetic status, the expression of genes can be regulated without any change in the DNA sequence itself. Epigenetic drugs exhibit promising therapeutic efficacy against several epigenetically originated diseases including several cancers, neurodegenerative diseases, metabolic disorders, cardiovascular disorders, and so forth. Currently, a considerable amount of research is focused on discovering new drug molecules to combat the existing research gap in epigenetic drug therapy. A novel and efficient delivery system can be established as a promising approach to overcome the drawbacks associated with the current epigenetic modulators. Therefore, formulating the existing epigenetic drugs with distinct encapsulation strategies in nanocarriers, including solid lipid nanoparticles, nanogels, bio-engineered nanocarriers, liposomes, surface modified nanoparticles, and polymer-drug conjugates have been examined for therapeutic efficacy. Nonetheless, several epigenetic modulators are untouched for their therapeutic potential through different delivery strategies. This review provides a comprehensive up to date discussion on the research findings of various epigenetics mechanism, epigenetic modulators, and delivery strategies utilized to improve their therapeutic outcome. Furthermore, this review also highlights the recently emerged CRISPR tool for epigenome editing.

Special Issue: Nanotherapeutics in Women's Health Emerging Nanotechnologies for Triple-Negative Breast Cancer Treatment

Breast cancer appears as the major cause of cancer-related deaths in women, with more than 2 260 000 cases reported worldwide in 2020, resulting in 684 996 deaths. Triple-negative breast cancer (TNBC), characterized by the absence of estrogen, progesterone, and human epidermal growth factor type 2 receptors, represents ≈20% of all breast cancers. TNBC has a highly aggressive clinical course and is more prevalent in younger women. The standard therapy for advanced TNBC is chemotherapy, but responses are often short-lived, with high rate of relapse. The lack of therapeutic targets and the limited therapeutic options confer to individuals suffering from TNBC the poorest prognosis among breast cancer patients, remaining a major clinical challenge. In recent years, advances in cancer nanomedicine provided innovative therapeutic options, as nanoformulations play an important role in overcoming the shortcomings left by conventional therapies: payload degradation and its low solubility, stability, and circulating half-life, and difficulties regarding biodistribution due to physiological and biological barriers. In this integrative review, the recent advances in the nanomedicine field for TNBC treatment, including the novel nanoparticle-, exosome-, and hybrid-based therapeutic formulations are summarized and their drawbacks and challenges are discussed for future clinical applications.

Epigenetic therapy: Research progress of decitabine in the treatment of solid tumors

Decitabine's early successful therapeutic outcomes in hematologic malignancies have led to regulatory approvals from the Food and Drug Administration (FDA) and the European Medicines Agency (EMA) for addressing myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). These approvals have sparked keen interest in exploring the potential of decitabine for treating solid tumors. Continuous preclinical and clinical trials have proved that low doses of decitabine also bring benefits in treating solid tumors, and various proposed mechanisms attempt to explain the potential efficacy. It is important to note that the application of decitabine in solid tumors is still considered investigational. This article reviews the application mechanism and current status of decitabine in the treatment of solid tumors.

Nanoemulsion potentiates the anti-cancer activity of Myricetin by effective inhibition of PI3K/AKT/mTOR pathway in triple-negative breast cancer cells

Triple-negative breast cancer (TNBC) is a heterogeneous tumor with a poor prognosis and high metastatic potential, resulting in poor clinical outcomes, necessitating investigation to devise effective therapeutic strategies. Multiple studies have substantiated the anti-cancer properties of the naturally occurring flavonoid "Myricetin" in various malignancies. However, the therapeutic application of Myricetin is impeded by its poor water solubility and low oral bioavailability. To overcome this limitation, we aimed to develop nanoemulsion of Myricetin (Myr-NE) and evaluate its advantage over Myricetin alone in TNBC cells. The nanoemulsion was formulated using Capryol 90 (oil), Tween 20 (surfactant), and Transcutol HP (co-surfactant). The optimized nano-formulation underwent an evaluation to determine its size, zeta potential, morphology, stability, drug encapsulation efficiency, and in vitro release properties. The anti-cancer activity of Myr-NE was further studied to examine its distinct impact on intracellular drug uptake, cell-viability, anti-tumor signaling, oxidative stress, clonogenicity, and cell death, compared with Myricetin alone in MDA-MB-231 (TNBC) cells. The in vitro drug release and intracellular drug uptake of Myricetin was significantly increased in Myr-NE formulation as compared to Myricetin alone. Moreover, Myr-NE exhibited significant inhibition of cell proliferation, clonogenicity, and increased apoptosis with ~ 2.5-fold lower IC50 as compared to Myricetin. Mechanistic investigation revealed that nanoemulsion augmented the anti-cancer efficacy of Myricetin, most likely by inhibiting the PI3K/AKT/mTOR pathway, eventually leading to enhanced cell death in TNBC cells. The study provides substantial experimental evidence to support the notion that the Myr-NE formulation has the potential to be an effective therapeutic drug for TNBC treatment.

Advances in the Delivery and Development of Epigenetic Therapeutics for the Treatment of Cancer

Gene expression at the transcriptional level is altered by epigenetic modifications such as DNA methylation, histone methylation, and acetylation, which can upregulate, downregulate, or entirely silence genes. Pathological dysregulation of epigenetic processes can result in the development of cancer, neurological problems, metabolic disorders, and cardiovascular diseases. It is of promising therapeutic interest to find medications that target these epigenetic alterations. Despite the enormous amount of work that has been done in this area, very few molecules have been approved for clinical purposes. This article provides a comprehensive review of recent advances in epigenetic therapeutics for cancer, with a specific focus on emerging delivery and development strategies. Various delivery systems, including pro-drugs, conjugated molecules, nanoparticles (NPs), and liposomes, as well as remedial strategies such as combination therapies, and epigenetic editing, are being investigated to improve the efficacy and specificity of epigenetic drugs (epi-drugs). Furthermore, the challenges associated with available epi-drugs and the limitations of their translation into clinics have been discussed. Target selection, isoform selectivity, physiochemical properties of synthesized molecules, drug screening, and scalability of epi-drugs from preclinical to clinical fields are the major shortcomings that are addressed. This Review discusses novel strategies for the identification of new biomarkers, exploration of the medicinal chemistry of epigenetic modifiers, optimization of the dosage regimen, and design of proper clinical trials that will lead to better utilization of epigenetic modifiers over conventional therapies. The integration of these approaches holds great potential for improving the efficacy and precision of epigenetic treatments, ultimately benefiting cancer patients.

Integration of an LPAR1 Antagonist into Liposomes Enhances Their Internalization and Tumor Accumulation in an Animal Model of Human Metastatic Breast Cancer

Lysophosphatidic acid receptor 1 (LPAR1) is elevated in breast cancer. The deregulation of LPAR1, including the function and level of expression, is linked to cancer initiation, progression, and metastasis. LPAR1 antagonists, AM095 or Ki16425, may be effective therapeutic molecules, yet their limited water solubility hinders in vivo delivery. In this study, we report on the synthesis of two liposomal formulations incorporating AM095 or Ki16425, embedded within the lipid bilayer, as targeted nanocarriers for metastatic breast cancer (MBC). The data show that the Ki16425 liposomal formulation exhibited a 50% increase in internalization by MBC mouse epithelial cells (4T1) and a 100% increase in tumor accumulation in a mouse model of MBC compared with that of a blank liposomal formulation (control). At the same time, normal mouse epithelial cells (EpH-4Ev) internalized the Ki16425 liposomal formulation 25% lesser than the control formulation. Molecular dynamics simulations show that the integration of AM095 or Ki16425 modified the physical and mechanical properties of the lipid bilayer, making it more flexible in these liposomal formulations compared with liposomes without drug. The incorporation of an LPAR1 antagonist within a liposomal drug delivery system represents a viable therapeutic approach for targeting the LPA-LPAR1 axis, which may hinder the progression of MBC.

Nanomedicine and epigenetics: New alliances to increase the odds in pancreatic cancer survival

Pancreatic ductal adenocarcinoma (PDAC) is among the deadliest cancers worldwide, primarily due to its robust desmoplastic stroma and immunosuppressive tumor microenvironment (TME), which facilitate tumor progression and metastasis. In addition, fibrous tissue leads to sparse vasculature, high interstitial fluid pressure, and hypoxia, thereby hindering effective systemic drug delivery and immune cell infiltration. Thus, remodeling the TME to enhance tumor perfusion, increase drug retention, and reverse immunosuppression has become a key therapeutic strategy. In recent years, targeting epigenetic pathways has emerged as a promising approach to overcome tumor immunosuppression and cancer progression. Moreover, the progress in nanotechnology has provided new opportunities for enhancing the efficacy of conventional and epigenetic drugs. Nano-based drug delivery systems (NDDSs) offer several advantages, including improved drug pharmacokinetics, enhanced tumor penetration, and reduced systemic toxicity. Smart NDDSs enable precise targeting of stromal components and augment the effectiveness of immunotherapy through multiple drug delivery options. This review offers an overview of the latest nano-based approaches developed to achieve superior therapeutic efficacy and overcome drug resistance. We specifically focus on the TME and epigenetic-targeted therapies in the context of PDAC, discussing the advantages and limitations of current strategies while highlighting promising new developments. By emphasizing the immense potential of NDDSs in improving therapeutic outcomes in PDAC, our review paves the way for future research in this rapidly evolving field.

Cancer nanomedicine: a review of nano-therapeutics and challenges ahead

Cancer is known as the most dangerous disease in the world in terms of mortality and lack of effective treatment. Research on cancer treatment is still active and of great social importance. Since 1930, chemotherapeutics have been used to treat cancer. However, such conventional treatments are associated with pain, side effects, and a lack of targeting. Nanomedicines are an emerging alternative due to their targeting, bioavailability, and low toxicity. Nanoparticles target cancer cells via active and passive mechanisms. Since FDA approval for Doxil®, several nano-therapeutics have been developed, and a few have received approval for use in cancer treatment. Along with liposomes, solid lipid nanoparticles, polymeric nanoparticles, and nanoemulsions, even newer techniques involving extracellular vesicles (EVs) and thermal nanomaterials are now being researched and implemented in practice. This review highlights the evolution and current status of cancer therapy, with a focus on clinical/pre-clinical nanomedicine cancer studies. Insight is also provided into the prospects in this regard.

Lipid-core nanoparticles: Classification, preparation methods, routes of administration and recent advances in cancer treatment

Nanotechnological drug delivery platforms represent a new paradigm for cancer therapeutics as they improve the pharmacokinetic profile and distribution of chemotherapeutic agents over conventional formulations. Among nanoparticles, lipid-based nanoplatforms possessing a lipid core, that is, lipid-core nanoparticles (LCNPs), have gained increasing interest due to lipid properties such as high solubilizing potential, versatility, biocompatibility, and biodegradability. However, due to the wide spectrum of morphologies and types of LCNPs, there is a lack of consensus regarding their terminology and classification. According to the current state-of-the-art in this critical review, LCNPs are defined and classified based on the state of their lipidic components in liquid lipid nanoparticles (LLNs). These include lipid nanoemulsions (LNEs) and lipid nanocapsules (LNCs), solid lipid nanoparticles (SLNs) and nanostructured lipid nanocarriers (NLCs). In addition, we present a comprehensive and comparative description of the methods employed for their preparation, routes of administration and the fundamental role of physicochemical properties of LCNPs for efficient antitumoral drug-delivery application. Market available LCNPs, clinical trials and preclinical in vivo studies of promising LCNPs as potential treatments for different cancer pathologies are summarized.

Targeted treatment of triple-negative-breast cancer through pH-triggered tumour associated macrophages using smart theranostic nanoformulations

Triple-negative breast cancer (TNBC) represents 15-25 % of the new breast cancer cases diagnosed worldwide every year. TNBC is among the most aggressive and worst prognosis breast cancer, mainly because targeted therapies are not available. Herein, we developed a magnetic theranostic hybrid nanovehicle for targeted treatment of TNBC through pH-triggered tumour associated macrophages (TAMs) targeting. The lipid core of the nanovehicle was composed of a Carnaúba wax matrix that simultaneously incorporated iron oxide nanoparticles and doxorubicin (DOX) - a chemotherapeutic drug. These drug-loaded wax nanovehicles were modified with a combination of two functional and complementary molecules: (i) a mannose ligand (macrophage targeting) and (ii) an acid-sensitive sheddable polyethylene glycol (PEG) moiety (specificity). The TAMs targeting strategy relied on the mannose - mannose receptor recognition exclusively after acid-sensitive "shedding" of the PEG in the relatively low tumour microenvironment pH. The pH-induced targeting capability towards TAMs was confirmed in vitro in a J774A.1 macrophage cell line at different pH (7.4 and 6.5). Biocompatibility and efficacy of the final targeted formulations were demonstrated in vitro in the TNBC MDA-MB-231 cell line and in vivo in an M-Wnt tumour-bearing (TNBC) mouse model. A preferential accumulation of the DOX-loaded lipid nanovehicles in the tumours of M-Wnt-tumour bearing mice was observed, which resulted both on an efficient tumour growth inhibition and a significantly reduced off-target toxicity compared to free DOX. Additionally, the developed magnetic hybrid nanovehicles showed outstanding performances as T₂-contrast agents in magnetic resonance imaging (r₂ ≈ 400-600 mM^-1·s^-1) and as heat generating sources in magnetic hyperthermia (specific absorption rate, SAR ≈ 178 W·g^-1_Fe). These targeted magnetic hybrid nanovehicles emerge as a suitable theranostic option that responds to the urgent demand for more precise and personalized treatments, not only because they are able to offer localized imaging and therapeutic potential, but also because they allow to efficiently control the balance between safety and efficacy.

Updated insight into the characterization of nano-emulsions

INTRODUCTION

In most of the studies, nano-emulsion characterization is limited to their size distribution and zeta potential. In this review, we present an updated insight of the characterization methods of nano-emulsions, including new or unconventional experimental approaches to explore in depth the nano-emulsion properties.

AREA COVERED

We propose an overview of all the main techniques used to characterize nano-emulsions, including the most classical ones, up to in vitro, ex vivo and in vivo evaluation. Innovative approaches are then presented in the second part of the review that presents innovative, experimental techniques less known in the field of nano-emulsion such as the nanoparticle tracking analysis, small-angle X-ray scattering, Raman spectroscopy, and nuclear magnetic resonance. Finally, in the last part we discuss the use of lipophilic fluorescent probes and imaging techniques as an emerging tool to understand the nano-emulsion droplet stability, surface decoration, release mechanisms, and in vivo fate.

EXPERT OPINION

This review is mostly intended for a broad readership and provides key tools regarding the choice of the approach to characterize nano-emulsions. Innovative and uncommon methods will be precious to disclose the information potentially reachable behind a formulation of nano-emulsions, not always known in first intention and with conventional methods.

Lipid-Based Nanoparticles as a Pivotal Delivery Approach in Triple Negative Breast Cancer (TNBC) Therapy

Triple-negative breast cancer is considered the most aggressive type of breast cancer among women and the lack of expressed receptors has made treatment options substantially limited. Recently, various types of nanoparticles have emerged as a therapeutic option against TNBC, to elevate the therapeutic efficacy of the existing chemotherapeutics. Among the various nanoparticles, lipid-based nanoparticles (LNPs) viz. liposomes, nanoemulsions, solid lipid nanoparticles, nanostructured lipid nanocarriers, and lipid–polymer hybrid nanoparticles are developed for cancer treatment which is well confirmed and documented. LNPs include various therapeutic advantages as compared to conventional therapy and other nanoparticles, including increased loading capacity, enhanced temporal and thermal stability, decreased therapeutic dose and associated toxicity, and limited drug resistance. In addition to these, LNPs overcome physiological barriers which provide increased accumulation of therapeutics at the target site. Extensive efforts by the scientific community could make some of the liposomal formulations the clinical reality; however, the relatively high cost, problems in scaling up the formulations, and delivery in a more targetable fashion are some of the major issues that need to be addressed. In the present review, we have compiled the state of the art about different types of LNPs with the latest advances reported for the treatment of TNBC in recent years, along with their clinical status and toxicity in detail.

Current Strategies in Breast Cancer Therapy: Role of Epigenetics and Nanomedicine

Breast cancer (BC), the most common cancer in women, is incurable due to metastatic spread to distant organs. The existence of epigenetic dysregulation has been shown to contribute to the progression and even metastasize through the transition from epithelial to mesenchymal. Behind failure strategies of conventional treatments, fruitful outcomes of epigenetic drugs have provided the hope of solid tumor management where the reversal of acquired resistance of the cancer cells is possible by epigenome regulation. Several agents have been identified to target epigenetic regulators in the cancer cells exhibiting remarkable potential against solid tumors, including BC. However, unnecessary systemic exposure, solubility issues, and unsuitability for diseased conditions using conventional delivery systems limit their use as cancer therapeutics. The progression of nanotechnology in pharmaceutical delivery has revolutionized cancer therapy, where specific, targeted and efficient delivery of epigenetic agents for alteration of cancerous conditions are ensured. In this review, a focus is made on epigenetic alteration in BC condition with the deliverable potential of the nanocarriers toward the breast tumor microenvironment for proper management. The significance of targeting and controlled release of therapeutics in the improved targeting of cancer cells is highlighted.

Emergence of Nanotechnology as a Powerful Cavalry against Triple-Negative Breast Cancer (TNBC)

Triple-negative breast cancer (TNBC) is considered one of the un-manageable types of breast cancer, involving devoid of estrogen, progesterone, and human epidermal growth factor receptor 2 (HER 2) receptors. Due to their ability of recurrence and metastasis, the management of TNBC remains a mainstay challenge, despite the advancements in cancer therapies. Conventional chemotherapy remains the only treatment regimen against TNBC and suffers several limitations such as low bioavailability, systemic toxicity, less targetability, and multi-drug resistance. Although various targeted therapies have been introduced to manage the hardship of TNBC, they still experience certain limitations associated with the survival benefits. The current research thus aimed at developing and improving the strategies for effective therapy against TNBC. Such strategies involved the emergence of nanoparticles. Nanoparticles are designated as nanocavalries, loaded with various agents (drugs, genes, etc.) to battle the progression and metastasis of TNBC along with overcoming the limitations experienced by conventional chemotherapy and targeted therapy. This article documents the treatment regimens of TNBC along with their efficacy towards different subtypes of TNBC, and the various nanotechnologies employed to increase the therapeutic outcome of FDA-approved drug regimens.

Structural Basis of Targeted Imaging and Therapy in Cancer Explorations with the Epigenetic Drugs

Origin of cancer is strongly related to the unusual epigenetic regulation of gene function as indicated by recent reports. The covalent modifications to DNA or histones without affecting genomes that finally lead to phenotypical changes in cells or organisms are referred as "Epigenetics." The possibility to reprogram the epigenetics in the cancer epigenome is the most important target for cancer treatment and drug resistance. The development of epigenetic drugs holds a great potential for the current cancer therapeutic approaches. Nevertheless, targeting cancer epigenetic pathways is still exciting due to the lack of selective and effective small molecule compounds or drug molecules. Therefore, the current book chapter highlights epigenetic pathways for cancer and potential small molecule inhibitors and epidrugs targeting DNA methyltransferase, histone modification, and more new therapies with nanomaterials and imaging to improve the effectiveness of cancer treatment. The structural aspects on discovery of novel small molecules or drugs targeting epigenetic pathways in cancer exploration as promising strategies will be also discussed.

Recent advances in nanomedicine-based delivery of histone deacetylase inhibitors for cancer therapy

Histone deacetylase inhibitors (HDACi) are cancer therapeutics that operate at the epigenetic level and which have recently gained wide attention. However, the applications of HDACi are generally hindered by their poor physicochemical characteristics and unfavorable pharmacokinetic profile. Inspired by the approved nanomedicine-based drugs in the market, nanocarriers could provide a resort to circumvent the limitations imposed by HDACi. Enhanced tumor targeting, improved cellular uptake and reduced toxicity are major advantages offered by HDACi-loaded nanoparticles. More importantly, site-specific drug delivery can be achieved via engineered stimuli-responsive nanosystems. In this review we elucidate the anticancer mechanisms of HDACi and their structure-activity relationships, with a special focus on their nanomedicine-based delivery, different drug loading concepts and their implications.

Triple negative breast cancer and non-small cell lung cancer: Clinical challenges and nano-formulation approaches

Triple negative breast cancer (TNBC) and non-small cell lung cancer (NSCLC) are amongst the most aggressive forms of solid tumors. TNBC is highlighted by absence of genetic components of progesterone receptor, HER2/neu and estrogen receptor in breast cancer. NSCLC is characterized by integration of malignant carcinoma into respiratory system. Both cancers are associated with poor median and overall survival rates with low progression free survival with high incidences of relapse. These cancers are characterized by tumor heterogeneity, genetic mutations, generation of cancer-stem cells, immune-resistance and chemoresistance. Further, these neoplasms have been reported for tumor cross-talk into second primary cancers for each other. Current chemotherapeutic regimens include usage of multiple agents in tandem to affect tumor cells through multiple mechanisms with various such combinations being clinically tested. However, lack of controlled delivery and effective temporospatial presence of chemotherapeutics has resulted in suboptimal therapeutic response. Consequently, passive targeted albumin bound paclitaxel and PEGylated liposomal doxorubicin have been clinically used and tested with newer drugs for improved therapeutic efficacy in these cancers. Active targeting of nanocarriers against surface overexpressed proteins in both neoplasms have been explored. However, use of single agent nanoparticulate formulations against both cancers have failed to elicit desired outcomes. This review aims to identify clinical unmet need in these cancers while establishing a correlation with tested nano-formulation approaches and issues with preclinical to clinical translation. Lipid and polymer-based drug-drug and drug-gene combinatorial nanocarriers delivering multiple chemotherapeutics simultaneously to desired site of action have been detailed. Finally, emerging opportunities such as pharmacological targets (immune check point and epigentic modulators) as well as gene-based modulation (siRNA/CRISPR/Cas9) and the nano-formulation challenges for effective treatment of both cancers have been explored.

Enhanced antitumor efficacy of lapachol-loaded nanoemulsion in breast cancer tumor model

Lapachol (LAP) is a natural compound with various biological properties, including anticancer activity. However, its clinical application is limited due to the low aqueous solubility and potential adverse side effects. Nanoemulsions are drug delivery systems that can assist in the administration of hydrophobic drugs, increasing their bioavailability and protecting from degradation. Thus, this study aimed to prepare a LAP-loaded nanoemulsion (NE-LAP), and evaluate its antitumor activity. For this purpose, the nanoemulsion was prepared using a hot homogenization method and characterized morphologically by cryogenic transmission electron microscopy (cryo-TEM). Mean diameter, polydispersity index, and zeta potential was evaluated by DLS, encapsulation efficiency was measured by HPLC. Moreover, the short-term storage stability, the drug release and hemolysis in vitro was determined. Additionally, pharmacokinetic, toxicology and toxicity properties of99mTc-NE-LAP were evaluated in a breast cancer (4T1) tumor model. The cryo-TEM showed spherical globules, and the physicochemical characterization of NE-LAP showed a homogeneous stable nanoemulsion with a mean diameter of ∼170 nm, zeta potential of around -20 mV, and encapsulation greater than 85 %. In vitro studies validated that encapsulation did not impair the cytotoxicity activity of LAP. The nanoemulsion was successfully radiolabeled and 99mTc-NE-LAP showed prolonged blood circulation and tumor affinity was confirmed by tumor-to-muscle ratio. Moreover, NE-LAP showed higher antitumor activity than the free drug and the treatment did not result in any signs of toxicity. Therefore, these findings suggest that NE-LAP can be considered an effective strategy for cancer treatment.

Epigenetics in Breast Cancer Therapy-New Strategies and Future Nanomedicine Perspectives

Epigenetic dysregulation has been recognized as a critical factor contributing to the development of resistance against standard chemotherapy and to breast cancer progression via epithelial-to-mesenchymal transition. Although the efficacy of the first-generation epigenetic drugs (epi-drugs) in solid tumor management has been disappointing, there is an increasing body of evidence showing that epigenome modulation, in synergy with other therapeutic approaches, could play an important role in cancer treatment, reversing acquired therapy resistance. However, the epigenetic therapy of solid malignancies is not straightforward. The emergence of nanotechnologies applied to medicine has brought new opportunities to advance the targeted delivery of epi-drugs while improving their stability and solubility, and minimizing off-target effects. Furthermore, the omics technologies, as powerful molecular epidemiology screening tools, enable new diagnostic and prognostic epigenetic biomarker identification, allowing for patient stratification and tailored management. In combination with new-generation epi-drugs, nanomedicine can help to overcome low therapeutic efficacy in treatment-resistant tumors. This review provides an overview of ongoing clinical trials focusing on combination therapies employing epi-drugs for breast cancer treatment and summarizes the latest nano-based targeted delivery approaches for epi-drugs. Moreover, it highlights the current limitations and obstacles associated with applying these experimental strategies in the clinics.

Nanotechnology-Based Histone Deacetylase Inhibitors for Cancer Therapy

Histone deacetylase inhibitors (HDACi) have been approved and achieved success in hematologic malignancies. But its application in solid tumors still confronts big challenges and is hampered by low treatment efficacy. Nanotechnology has been widely applied in cancer therapy, and nanomedicine could improve drug stability, prolong the circulation half-life, and increase intratumoral drug accumulation. Therefore, nanomedicine is a promising strategy to enhance HDACi therapy efficacy. The review provides a summary of the advances of HDACi nanomedicines with a focus on the design principles of the targeting delivery systems for HDACi.

Current Applications of Nanoemulsions in Cancer Therapeutics

Nanoemulsions are pharmaceutical formulations composed of particles within a nanometer range. They possess the capacity to encapsulate drugs that are poorly water soluble due to their hydrophobic core nature. Additionally, they are also composed of safe gradient excipients, which makes them a stable and safe option to deliver drugs. Cancer therapy has been an issue for several decades. Drugs developed to treat this disease are not always successful or end up failing, mainly due to low solubility, multidrug resistance (MDR), and unspecific toxicity. Nanoemulsions might be the solution to achieve efficient and safe tumor treatment. These formulations not only solve water-solubility problems but also provide specific targeting to cancer cells and might even be designed to overcome MDR. Nanoemulsions can be modified using ligands of different natures to target components present in tumor cells surface or to escape MDR mechanisms. Multifunctional nanoemulsions are being studied by a wide variety of researchers in different research areas mainly for the treatment of different types of cancer. All of these studies demonstrate that nanoemulsions are efficiently taken by the tumoral cells, reduce tumor growth, eliminate toxicity to healthy cells, and decrease migration of cancer cells to other organs.