Doxorubicin and mitomycin C co-loaded polymer-lipid hybrid nanoparticles inhibit growth of sensitive and multidrug resistant human mammary tumor xenografts

Overcoming Chemotherapy Resistance in Metastatic Cancer: A Comprehensive Review

The management of metastatic cancer is complicated by chemotherapy resistance. This manuscript provides a comprehensive academic review of strategies to overcome chemotherapy resistance in metastatic cancer. The manuscript presents background information on chemotherapy resistance in metastatic cancer cells, highlighting its clinical significance and the current challenges associated with using chemotherapy to treat metastatic cancer. The manuscript delves into the molecular mechanisms underlying chemotherapy resistance in subsequent sections. It discusses the genetic alterations, mutations, and epigenetic modifications that contribute to the development of resistance. Additionally, the role of altered drug metabolism and efflux mechanisms, as well as the activation of survival pathways and evasion of cell death, are explored in detail. The strategies to overcome chemotherapy resistance are thoroughly examined, covering various approaches that have shown promise. These include combination therapy approaches, targeted therapies, immunotherapeutic strategies, and the repurposing of existing drugs. Each strategy is discussed in terms of its rationale and potential effectiveness. Strategies for early detection and monitoring of chemotherapy drug resistance, rational drug design vis-a-vis personalized medicine approaches, the role of predictive biomarkers in guiding treatment decisions, and the importance of lifestyle modifications and supportive therapies in improving treatment outcomes are discussed. Lastly, the manuscript outlines the clinical implications of the discussed strategies. It provides insights into ongoing clinical trials and emerging therapies that address chemotherapy resistance in metastatic cancer cells. The manuscript also explores the challenges and opportunities in translating laboratory findings into clinical practice and identifies potential future directions and novel therapeutic avenues. This comprehensive review provides a detailed analysis of strategies to overcome chemotherapy resistance in metastatic cancer. It emphasizes the importance of understanding the molecular mechanisms underlying resistance and presents a range of approaches for addressing this critical issue in treating metastatic cancer.

Patient-derived scaffolds representing breast cancer microenvironments influence chemotherapy responses in adapted cancer cells consistent with clinical features

BACKGROUND

The tumor microenvironment clearly influences cancer progressing properties but less is known about how individual cancer microenvironments potentially moderate cancer treatment effects. By cultivating and treating cancer cell lines in patient-derived scaffolds (PDS), the impact of specific characteristics of individual cancer microenvironments can be incorporated in human-like growth modelling and cancer drug treatment testing.

METHODS

PDSs from 78 biobanked primary breast cancer samples with known patient outcomes, were prepared and repopulated with donor breast cancer cell lines, followed by treatment with 5-fluorouracil or doxorubicin after cellular adaption to the various microenvironments. Cancer cell responses to the treatments were monitored by RNA-analyses, highlighting changes in gene sets representative for crucial tumor biological processes such as proliferation, cancer stem cell features, differentiation and epithelial-to-mesenchymal transition.

RESULTS

The chemotherapy treatments induced distinct gene expression patterns in adapted cancer cells with clusters of similar treatment responses depending on the patient-derived cancer microenvironment used as growth substrate. The doxorubicin treatment displayed a favorable gene signature among surviving cancer cells with low proliferation (MKI67) and pluripotency features (NANOG, POU5F1), in comparison to 5-fluorouracil showing low proliferation but increased pluripotency. Specific gene changes monitored post-treatment were also significantly correlated with clinical data, including histological grade (NANOG), lymph node metastasis (SLUG) and disease-free patient survival (CD44).

CONCLUSIONS

This laboratory-based treatment study using patient-derived scaffolds repopulated with cancer cell lines, clearly illustrates that the human cancer microenvironment influences chemotherapy responses. The differences in treatment responses defined by scaffold-cultures have potential prognostic and treatment predictive values.

Harnessing Nanomedicine to Potentiate the Chemo-Immunotherapeutic Effects of Doxorubicin and Alendronate Co-Encapsulated in Pegylated Liposomes

Encapsulation of Doxorubicin (Dox), a potent cytotoxic agent and immunogenic cell death inducer, in pegylated (Stealth) liposomes, is well known to have major pharmacologic advantages over treatment with free Dox. Reformulation of alendronate (Ald), a potent amino-bisphosphonate, by encapsulation in pegylated liposomes, results in significant immune modulatory effects through interaction with tumor-associated macrophages and activation of a subset of gamma-delta T lymphocytes. We present here recent findings of our research work with a formulation of Dox and Ald co-encapsulated in pegylated liposomes (PLAD) and discuss its pharmacological properties vis-à-vis free Dox and the current clinical formulation of pegylated liposomal Dox. PLAD is a robust formulation with high and reproducible remote loading of Dox and high stability in plasma. Results of biodistribution studies, imaging with radionuclide-labeled liposomes, and therapeutic studies as a single agent and in combination with immune checkpoint inhibitors or gamma-delta T lymphocytes suggest that PLAD is a unique product with distinct tumor microenvironmental interactions and distinct pharmacologic properties when compared with free Dox and the clinical formulation of pegylated liposomal Dox. These results underscore the potential added value of PLAD for chemo-immunotherapy of cancer and the relevance of the co-encapsulation approach in nanomedicine.

Lipid polymer hybrid nanoparticles: a custom-tailored next-generation approach for cancer therapeutics

Lipid-based polymeric nanoparticles are the highly popular carrier systems for cancer drug therapy. But presently, detailed investigations have revealed their flaws as drug delivery carriers. Lipid polymer hybrid nanoparticles (LPHNPs) are advanced core-shell nanoconstructs with a polymeric core region enclosed by a lipidic layer, presumed to be derived from both liposomes and polymeric nanounits. This unique concept is of utmost importance as a combinable drug delivery platform in oncology due to its dual structured character. To add advantage and restrict one's limitation by other, LPHNPs have been designed so to gain number of advantages such as stability, high loading of cargo, increased biocompatibility, rate-limiting controlled release, and elevated drug half-lives as well as therapeutic effectiveness while minimizing their drawbacks. The outer shell, in particular, can be functionalized in a variety of ways with stimuli-responsive moieties and ligands to provide intelligent holding and for active targeting of antineoplastic medicines, transport of genes, and theragnostic. This review comprehensively provides insight into recent substantial advancements in developing strategies for treating various cancer using LPHNPs. The bioactivity assessment factors have also been highlighted with a discussion of LPHNPs future clinical prospects.

ZEB1 potentiates chemoresistance in breast cancer stem cells by evading apoptosis

Chemoresistance renders a challenge to the clinics to treat breast cancer patients. Current treatment strategies are effective in mitigating tumor growth but remain largely ineffective against cancer-initiating cells or breast Cancer Stem Cells (CSCs). Epithelial-to-mesenchymal-transition (EMT) regulates breast CSC physiology. Zinc finger E-box binding homeobox 1 (ZEB1) is a key EMT-transcription factor that regulates breast CSC - differentiation and metastasis. However, its potential role in modulating tumor chemoresistance has not yet been fully understood. In-silico analysis revealed a higher ZEB1 expression in breast cancer patients that leads to decreased overall and relapse-free survival. We generated sorted breast CSC with stable ZEB1 overexpression (CD24-/CD44+GFP-ZEB1) and/or silencing (CD24-/CD44+ZEB1 shRNA) as well as breast cancer cells with stable ZEB1 overexpression (CD24+GFP-ZEB1) and/or silencing (CD24+ZEB1 shRNA). An increased colony-forming efficiency and doxorubicin accumulation correlated with decreased promoter activity and expression profile of ABCC1 drug-efflux ABC transporter in CD24-/CD44+GFP-ZEB1. Additionally, CD24-/CD44+GFP-ZEB1 demonstrated doxorubicin-induced higher anti-apoptotic and lower pro-apoptotic protein expressions in the mitochondrial and cytosolic fractions. Chemoresistant CD24-/CD44+GFP-ZEB1 cells depicted 1000-fold higher IC-50 values of doxorubicin and decreased activation of JNK-p38 stress kinase molecular signaling-dependent mammosphere forming efficiency to evade apoptosis. Thus, ZEB1 and its downstream effectors are plausible therapeutic targets for the mitigation of breast cancer chemoresistance in patients.

CMA mediates resistance in breast cancer models

BACKGROUND

Breast cancer (BC) is the most common malignancy in women and the second leading cause of cancer-related death; chemoresistance is still a clinical challenge mainly because of the different molecular features of this kind of tumour. Doxorubicin (Doxo) is widely used despite its adverse effects and the common onset of resistance. Chaperone-Mediated Autophagy (CMA) has been identified as an important mechanism through which chemotherapeutics can exert their cytotoxic effects and, in this context, LAMP-2A, the key player of CMA, can be a useful biomarker.

METHODS

A cohort of patients and breast cancer cells have been screened for Doxo effect and CMA activation by analysing the LAMP-2A level. Molecular silencing has been used to clarify CMA role in BC responsiveness to treatments. Low Doxo doses were combined with other drugs (TMZ or PX-478, a HIF-1α inhibitor) to evaluate their cytotoxic ability and their role in modulating CMA.

RESULTS

In this paper, we showed that CMA is an important mechanism mediating the responsiveness of breast cancer cell to different treatments (Doxo and TMZ, as suggested by triple negative cells that are TMZ-resistant and fails to activate CMA). The LAMP-2A expression level was specific for different cell lines and patient-derived tumour subtypes, and was also useful in discriminating patients for their survival rates. Moreover, molecular silencing or pharmacological blockage of HIF-1α activity reverted BC resistance to TMZ. The combination of low-dose Doxo with TMZ or PX-478 showed that the drug associations have synergistic behaviours.

CONCLUSION

Here, we demonstrated that CMA activity exerts a fundamental role in the responsiveness to different treatments, and LAMP-2A can be proposed as a reliable prognostic biomarker in breast cancer. In this context, HIF-1α, a potential target of CMA, can also be assessed as a valuable therapeutic target in BC in view of identifying new, more efficient and less toxic therapeutic drug combinations. Moreover, the possibility to combine Doxo with other drugs acting on different but coherent molecular targets could help overcome resistance and open the way to a decrease in the dose of the single drugs.

A novel thermoresponsive nano carrier matrix of hyaluronic acid, methotrexate and chitosan to target the cluster of differentiation 44 receptors in tumors

Major challenges in current cancer chemotherapy include drug resistance, low efficacy and non-selectivity, resulting in undesirable side effects. In this study, we demonstrate a solution to these challenges that involves a dual targeting approach for tumors that overexpress CD44 receptors. The approach employs a nano-formulation (tHAC-MTX nano assembly), fabricated from hyaluronic acid (HA), the natural ligand for CD44, conjugated with methotrexate (MTX) and complexed with the thermoresponsive polymer 6-O-carboxymethylchitosan (6-OCMC) graft poly(N-isopropylacrylamide) [6-OCMC-g-PNIPAAm]. The thermoresponsive component was designed to have a lower critical solution temperature of 39 °C (the temperature of tumor tissues). In-vitro drug release studies reveal faster release of the drug at the higher temperatures of the tumor tissue likely due to the conformation changes in the thermoresponsive component of the nano assembly. Drug release was also enhanced in the presence of hyaluronidase enzyme. Higher cellular uptake and greater cytotoxicity of the nanoparticles were demonstrated in cancer cells that overexpress CD44 receptors suggesting a receptor binding and cellular uptake mechanism. Such nano-assemblies which incorporate multiple targeting mechanisms have the potential to improve efficacy and decrease side effects of cancer chemotherapy.

Application of Dual-Drug Loaded Metal Organic Framework Nanomaterials Targeting PI3K Signaling Pathway in Triple Negative Breast Cancer Cells

Aim: To design a new treatment based AKT inhibitor (MLF), as a therapeutic target, and doxorubicin, as a chemotherapy agent, co-loaded on Modern metal organic frameworks (MFOs) by using ZIF-8 nanomaterials. Methods: We synthesized a MOFs (ZIF-8) as a drug carrier, and achieved simultaneous loading of the chemotherapeutic drug DOX and AKT inhibitor MFL (ZIF-8/DOX/MFL), as a drug carrier. In addition, we used MTT assay, evaluation the expression of collagen-1, and tumor drug uptake to evaluate the efficacy of our treatment. We further used ultrasound to modify the red blood cell membrane on the surface of ZIF-8/DOX/MLF to improve the biological safety and stability of the drug-carrying system, and finally obtained ZIF-8/DOX/MLF/RBCM. Results: Our results showed that the tumor enrichment in the ZIF-8/MLF/RBCM group was about 3 times that of the ZIF-8/RBCM group; and both in vivo and in vitro imaging of mouse organs showed that MLF has the function of assisting drug delivery and enhancing drug tumor enrichment, according to fluorescence quantification. Conclusion: The research results show that the ZIF-8/DOX/MLF/RBCM can achieve the purpose of sensitizing new tumor chemotherapy in breast cancer.

N-acetyl-galactosamine modified metal-organic frameworks to inhibit the growth and pulmonary metastasis of liver cancer stem cells through targeted chemotherapy and starvation therapy

Hepatocellular carcinoma (HCC) is a common high-mortality malignancy which still needs efficient treatments. HCC patients undergoing extrahepatic metastases are mostly with unsatisfactory prognosis. Therefore, specific attention has been paid to extrahepatic HCC metastasis. We integrated Sorafenib (Sor) and glucose oxidase (GOx) into a N-acetyl-galactosamine (GalNAc) modified zeolitic imidazolate framework (ZIF-8), designated as SG@GR-ZIF-8, for targeted bimodal therapies of chemotherapy and starvation therapy against HCC. The hepatic delivery of SG@GR-ZIF was mediated by the specific recognition of GalNAc residues with asialoglycoprotein (ASGPR) on the liver cell surface. Sor is a clinically approved anti-proliferation and anti-angiogenesis drug for advanced HCC treatment. GOx can efficiently induce cell death and disturb malignant progression by suppressing glucose supply of cancer cells, which is highly associated with metabolic rewiring in metastasis. The nano-formulation exhibit significant anti-metastatic HCC activity against C5WN1 cells, a liver cancer stem cell-like cell line with tumorigenicity and pulmonary metastasis activity. In a subcutaneous C5WN1-tumor carrying mouse model, SG@GR-ZIF exhibits potent synergistic anti-tumor activity with a tumor inhibition rate of 89% and a prolonged survival status. The growth and pulmonary metastasis of HCC in an orthotopic mouse model of HCC was remarkably suppressed in SG@GR-ZIF treated group. The therapeutic strategy targeting energy supply combined with first-line treatment holds great promise for the future treatment of metastatic HCC. STATEMENT OF SIGNIFICANCE: : SG@GR-ZIF, a N-acetyl-galactosamine modified metal-organic framework carrying Sorafenib and glucose oxidase, was fabricated for treating metastatic hepatocellular carcinoma (HCC). Sorafenib is an anti-proliferation and anti-angiogenesis drug for advanced HCC treatment. Glucose oxidase blocks energy demand in HCC metastasis by depleting glucose. C5WN1 was used for therapeutic evaluations as a liver cancer stem cell-like cell line with tumorigenicity and pulmonary metastasis activity. In subcutaneous C5WN1-tumor bearing mice, SG@GR-ZIF exhibited a tumor inhibition rate of 89% and prolonged survival period. In orthotopic C5WN1-tumor carrying mice, the growth and pulmonary metastasis of hepatocarcinoma was remarkably suppressed by SG@GR-ZIF. Together, this study suggests the great potential of synergistic chemo/starvation therapy mediated by SG@GR-ZIF for treating metastatic HCC.

Advances in Nanomedicine Design: Multidisciplinary Strategies for Unmet Medical Needs

Globally, a rising burden of complex diseases takes a heavy toll on human lives and poses substantial clinical and economic challenges. This review covers nanomedicine and nanotechnology-enabled advanced drug delivery systems (DDS) designed to address various unmet medical needs. Key nanomedicine and DDSs, currently employed in the clinic to tackle some of these diseases, are discussed focusing on their versatility in diagnostics, anticancer therapy, and diabetes management. First-hand experiences from our own laboratory and the work of others are presented to provide insights into strategies to design and optimize nanomedicine- and nanotechnology-enabled DDS for enhancing therapeutic outcomes. Computational analysis is also briefly reviewed as a technology for rational design of controlled release DDS. Further explorations of DDS have illuminated the interplay of physiological barriers and their impact on DDS. It is demonstrated how such delivery systems can overcome these barriers for enhanced therapeutic efficacy and how new perspectives of next-generation DDS can be applied clinically.

Rational Mitomycin Nanocarriers Based on Hydrophobically Functionalized Polyelectrolytes and Poly(lactide-co-glycolide)

Encapsulation of hydrophilic and amphiphilic drugs in appropriate colloidal carrier systems for sustained release is an emerging problem. In general, hydrophobic bioactive substances tend to accumulate in water-immiscible polymeric domains, and the release process is controlled by their low aqueous solubility and limited diffusion from the nanocarrier matrix. Conversely, hydrophilic/amphiphilic drugs are typically water-soluble and insoluble in numerous polymers. Therefore, a core-shell approach─nanocarriers comprising an internal core and external shell microenvironments of different properties─can be exploited for hydrophilic/amphiphilic drugs. To produce colloidally stable poly(lactic-co-glycolic) (PLGA) nanoparticles for mitomycin C (MMC) delivery and controlled release, a unique class of amphiphilic polymers─hydrophobically functionalized polyelectrolytes─were utilized as shell-forming materials, comprising both stabilization via electrostatic repulsive forces and anchoring to the core via hydrophobic interactions. Undoubtedly, the use of these polymeric building blocks for the core-shell approach contributes to the enhancement of the payload chemical stability and sustained release profiles. The studied nanoparticles were prepared via nanoprecipitation of the PLGA polymer and were dissolved in acetone as a good solvent and in an aqueous solution containing hydrophobically functionalized poly(4-styrenesulfonic-co-maleic acid) and poly(acrylic acid) of differing hydrophilic-lipophilic balance values. The type of the hydrophobically functionalized polyelectrolyte (HF-PE) was crucial for the chemical stability of the payload─derivatives of poly(acrylic acid) were found to cause very rapid degradation (hydrolysis) of MMC, in contrast to poly(4-styrenesulfonic-co-maleic acid). The present contribution allowed us to gain crucial information about novel colloidal nanocarrier systems for MMC delivery, especially in the fields of optimal HF-PE concentrations, appropriate core and shell building materials, and the colloidal and chemical stability of the system.

Emerging Biomaterials-Based Strategies for Inhibiting Vasculature Function in Cancer Therapy

The constant feeding of oxygen and nutrients through the blood vasculature has a vital role in maintaining tumor growth. Interestingly, recent endeavors have shown that nanotherapeutics with the strategy to block tumor blood vessels feeding nutrients and oxygen for starvation therapy can be helpful in cancer treatment. However, this field has not been detailed. Hence, this review will present an exhaustive summary of the existing biomaterial based strategies to disrupt tumor vascular function for effective cancer treatment, including hydrogel or nanogel-mediated local arterial embolism, thrombosis activator loaded nano-material-mediated vascular occlusion and anti-vascular drugs that block tumor vascular function, which may be beneficial to the design of anti-cancer nanomedicine by targeting the tumor vascular system.

Exploring the transformability of polymer-lipid hybrid nanoparticles and nanomaterial-biology interplay to facilitate tumor penetration, cellular uptake and intracellular targeting of anticancer drugs

BACKGROUND

Successful delivery of anticancer drugs to intracellular targets requires different properties of the nanocarrier to overcome multiple transport barriers. However, few nanocarrier systems, to date, possess such properties, despite knowledge about the biological fate of inorganic and polymeric nanocarriers in relation to their fixed size, shape and surface properties. Herein, a polymer-lipid hybrid nanoparticle (PLN) system is described with size and shape transformability and its mechanisms of cellular uptake and intracellular trafficking are studied.

METHODS

Pharmaceutical lipids were screened for use in transformable PLN. Mechanisms of cellular uptake and the role of fatty acid-binding proteins in intracellular trafficking of PLN were investigated in breast cancer cells. Intra-tumoral penetration and retention of doxorubicin (DOX) were evaluated by confocal microscopy.

RESULTS

The lead PLNs showed time-dependent size reduction and shape change from spherical to spiky shape. This transformability of PLNs and lipid trafficking pathways facilitated intracellular transport of DOX-loaded PLN (DOX-PLN) into mitochondria and nuclei. DOX-PLN significantly increased DOX penetration and retention over free DOX or non-transformable liposomal DOX particles at 4 h post-intravenous administration.

CONCLUSION

Transformability of PLN and lipid-biology interplay can be exploited to design new nanocarriers for effective drug delivery to tumor cells and intracellular targets.

Exciting Potential of Nanoparticlized Lipidic System for Effective Treatment of Breast Cancer and Clinical Updates: A Translational Prospective

Breast cancer (BC) is a multifactorial disease and becoming a major health issue in women throughout the globe. BC is a malignant type of cancer which results from transcriptional changes in proteins and genes. Besides the availability of modern medicines and detection tools, BC has become a topmost deadly disease and its cure still remains challenging. Nanotechnology based approaches are being employed for the diagnosis and treatment of BC at clinical stages. Nanosystems have a significant role in the study of the interaction of malignant cells with their microenvironment through receptor-based targeted approach. Nowadays, lipid-based nanocarriers are being popularized in the domain of pharmaceutical and medical biology for cancer therapy. Lipidic nanoparticlized systems (LNPs) have proven to have high loading efficiency, less toxicity, improved therapeutic efficacy, enhanced bioavailability and stability of the bioactive compounds compared to traditional drug delivery systems. In the present context, several LNPs based formulations have been undertaken in various phases of clinical trials in different countries. This review highlights the importance of chemotherapeutics based lipidic nanocarriers and their anticipated use for the treatment of BC. Furthermore, the clinical trials and future prospective of LNPs have been widely elaborated.

Recent Advancements of Nanomedicine towards Antiangiogenic Therapy in Cancer

Angiogenesis is a process of generation of de-novo blood vessels from already existing vasculature. It has a crucial role in different physiological process including wound healing, embryonic development, and tumor growth. The methods by which therapeutic drugs inhibit tumor angiogenesis are termed as anti-angiogenesis cancer therapy. Developments of angiogenic inhibiting drugs have various limitations causing a barrier for successful treatment of cancer, where angiogenesis plays an important role. In this context, investigators developed novel strategies using nanotechnological approaches that have demonstrated inherent antiangiogenic properties or used for the delivery of antiangiogenic agents in a targeted manner. In this present article, we decisively highlight the recent developments of various nanoparticles (NPs) including liposomes, lipid NPs, protein NPs, polymer NPs, inorganic NPs, viral and bio-inspired NPs for potential application in antiangiogenic cancer therapy. Additionally, the clinical perspectives, challenges of nanomedicine, and future perspectives are briefly analyzed.

Improvement in the Anti-Tumor Efficacy of Doxorubicin Nanosponges in In Vitro and in Mice Bearing Breast Tumor Models

Doxorubicin (DOX) is an anthracycline widely used in cancer therapy and in particular in breast cancer treatment. The treatment with DOX appears successful, but it is limited by a severe cardiotoxicity. This work evaluated the in vitro and in vivo anticancer effect of a new formulation of β-cyclodextrin nanosponges containing DOX (BNS-DOX). The BNS-DOX effectiveness was evaluated in human and mouse breast cancer cell lines in vitro in terms of effect on cell growth, cell cycle distribution, and apoptosis induction; and in vivo in BALB-neuT mice developing spontaneous breast cancer in terms of biodistribution, cancer growth inhibition, and heart toxicity. BNS-DOX significantly inhibited cancer cell proliferation, through the induction of apoptosis, with higher efficiency than free DOX. The breast cancer growth in BALB-neuT mice was inhibited by 60% by a BNS-DOX dose five times lower than the DOX therapeutic dose, with substantial reduction of tumor neoangiogenesis and lymphangiogenesis. Biodistribution after BNS-DOX treatment revealed a high accumulation of DOX in the tumor site and a low accumulation in the hearts of mice. Results indicated that use of BNS may be an efficient strategy to deliver DOX in the treatment of breast cancer, since it improves the anti-cancer effectiveness and reduces cardiotoxicity.

Overcoming multidrug resistance in cancer: Recent progress in nanotechnology and new horizons

Multidrug resistance (MDR), defined as the ability of cancer cells to gain resistance to both conventional and novel chemotherapy agents, is an important barrier in treating malignancies. Initially, it was discovered that cellular pumps dependent on ATP were the cause of resistance to chemotherapy, and further studies have found that other mechanisms such as increased metabolism of drugs, decreased drug entry, and defective apoptotic pathways are involved in this process. MDR has been the focus of numerous initiatives and countless studies have been undertaken to better understand MDR and formulate strategies to overcome its effects. The current review highlights various nano-drug delivery systems including polymeric/solid lipid/mesoporous silica/metal nanoparticles, dendrimers, liposomes, micelles, and nanostructured lipid carriers to overcome the mechanism of MDR. Nanoparticles are novel gateways to enhance the therapeutic efficacy of anticancer agents at the target site of action due to their tumor-targeting abilities, which can limit the unwanted systemic effects of chemotherapy agents and also reduce drug resistance. Additionally, other innovative strategies including RNA interference as a biological process used to inhibit or silence specific gene expression, natural products as MDR modulators with little systemic toxic effects, which interfere with the functions of proteins involved in drug efflux, and physical approaches such as combination of conventional drug administration with thermal/ultrasound/photodynamic strategies are also highlighted.

Development of Promitil®, a lipidic prodrug of mitomycin c in PEGylated liposomes: From bench to bedside

Several liposome products have been approved for the treatment of cancer. In all of them, the active agents are encapsulated in the liposome water phase passively or by transmembrane ion gradients. An alternative approach in liposomal drug delivery consists of chemically modifying drugs to form lipophilic prodrugs with strong association to the liposomal bilayer. Based on this approach, we synthesized a mitomycin c-derived lipidic prodrug (MLP) which is entrapped in the bilayer of PEGylated liposomes (PL-MLP, Promitil®), and activated by thiolytic cleavage. PL-MLP is stable in plasma with thiolytic activation of MLP occurring exclusively in tissues and is more effective and less toxic than conventional chemotherapy in various tumor models. PL-MLP has completed phase I clinical development where it has shown a favorable safety profile and a 3-fold reduction in toxicity as compared to free mitomycin c. Clinical and pharmacokinetic studies in patients with advanced colo-rectal carcinoma have indicated a significant rate of disease stabilization (39%) in this chemo-refractory population and significant prolongation of median survival in patients attaining stable disease (13.9 months) versus progressive disease patients (6.35 months). The pharmacokinetics of MLP was typically stealth with long T½ (~1 day), slow clearance and small volume of distribution. Interestingly, a longer T½, and slower clearance were both correlated with disease stabilization and longer survival. This association of pharmacokinetic parameters with patient outcome suggests that arrest of tumor growth is related to the enhanced tumor localization of long-circulating liposomes and highlights the importance of personalized pharmacokinetic evaluation in the clinical use of nanomedicines. Another important area where PL-MLP may have an added value is in chemoradiotherapy, where it has shown a strong radiosensitizing effect in animal models based on a unique mechanism of enhanced prodrug activation and encouraging results in early human testing.

Bioinspired Polymeric-based Core-shell Smart Nano-systems

Smart nanosystems (SNs) have the potential to revolutionize drug delivery. Conventional drug delivery systems have poor drug-loading, early burst release, limited therapeutic effects, etc. Thus, to overcome these problems, researchers have taken advantage of the host-guest interactions as bioinspired nanosystems which can deliver nanocarriers more efficiently with the maximum drug loading capacity and improved therapeutic efficacy as well as bioavailability. SNs employ nanomaterials to form cage molecules by entrapping new nanocarriers called smart nanosystems in their cargo and design. The activities of SNs are based on responsive materials that interact with the stimuli either by changing their properties or conformational structures. The aptitude of living systems to respond to stimuli and process information has encouraged researchers to build up integrated nanosystems exhibiting similar function and therapeutic response. Various smart materials, including polymers, have been exhaustively employed in fabricating different stimuli-responsive nanosystems which can deliver bioactive molecules to a specific site for a certain period with minimal side effects. SNs have been widely explored to deliver diverse kinds of therapeutic agents ranging from bioactive compounds, genes, and biopharmaceuticals like proteins and peptides, to diagnostic imaging agents for biomedical applications. Nanotechnology-based different nanosystems are promising for health care issues. The advancement of SNs with physical science and engineering technology in synthesizing nanostructures and their physicochemical characterization should be exploited in medicine and healthcare for reducing mortality rate, morbidity, disease prevalence and general societal burden.

Drug Combinations in Breast Cancer Therapy

Breast cancer therapy involves a multidisciplinary approach comprising surgery, radiotherapy, neoadjuvant and adjuvant therapy. Effective therapy of breast cancer requires maximum therapeutic efficacy, with minimal undesirable effects to ensure a good quality of life for patients. The carefully selected combination of therapeutic interventions provides patients with the opportunity to derive maximum benefit from therapy while minimizing or eliminating recurrence, resistance and toxic effects, as well as ensuring that patients have a good quality of life. This review discusses therapeutic options for breast cancer treatments and various combinations that had been previously exploited. The review will also give an insight into the potential application of the nanotechnology platform for codelivery of therapeutics in breast cancer therapy.

Advances in nanomedicine for cancer starvation therapy

Abnormal cell metabolism with vigorous nutrition consumption is one of the major physiological characteristics of cancers. As such, the strategy of cancer starvation therapy through blocking the blood supply, depleting glucose/oxygen and other critical nutrients of tumors has been widely studied to be an attractive way for cancer treatment. However, several undesirable properties of these agents, such as low targeting efficacy, undesired systemic side effects, elevated tumor hypoxia, induced drug resistance, and increased tumor metastasis risk, limit their future applications. The recent development of starving-nanotherapeutics combined with other therapeutic methods displayed the promising potential for overcoming the above drawbacks. This review highlights the recent advances of nanotherapeutic-based cancer starvation therapy and discusses the challenges and future prospects of these anticancer strategies.

Evaluation of Polymer Nanoformulations in Hepatoma Therapy by Established Rodent Models

Hepatoma is one of the most severe malignancies usually with poor prognosis, and many patients are insensitive to the existing therapeutic agents, including the drugs for chemotherapy and molecular targeted therapy. Currently, researchers are committed to developing the advanced formulations with controlled drug delivery to improve the efficacy of hepatoma therapy. Numerous inoculated, induced, and genetically engineered hepatoma rodent models are now available for formulation screening. However, animal models of hepatoma cannot accurately represent human hepatoma in terms of histological characteristics, metastatic pathways, and post-treatment responses. Therefore, advanced animal hepatoma models with comparable pathogenesis and pathological features are in urgent need in the further studies. Moreover, the development of nanomedicines has renewed hope for chemotherapy and molecular targeted therapy of advanced hepatoma. As one kind of advanced formulations, the polymer-based nanoformulated drugs have many advantages over the traditional ones, such as improved tumor selectivity and treatment efficacy, and reduced systemic side effects. In this article, the construction of rodent hepatoma model and much information about the current development of polymer nanomedicines were reviewed in order to provide a basis for the development of advanced formulations with clinical therapeutic potential for hepatoma.

Drug delivery systems for elemene, its main active ingredient β-elemene, and its derivatives in cancer therapy

β-elemene is a noncytotoxic Class II antitumor drug extracted from the traditional Chinese medicine Curcuma wenyujin Y. H. Chen et C. Ling. β-elemene exerts its effects by inhibiting cell proliferation, arresting the cell cycle, inducing cell apoptosis, exerting antiangiogenesis and antimetastasis effects, reversing multiple-drug resistance (MDR), and enhancing the immune system. Elemene injection and oral emulsion have been used to treat various tumors, including cancer of the lung, liver, brain, breast, ovary, gastric, prostate, and other tissues, for >20 years. The safety of both elemene injection and oral emulsion in the clinic has been discussed. Recently, the secondary development of β-elemene has attracted the attention of researchers and made great progress. On the one hand, studies have been carried out on liposome-based systems (including solid lipid nanoparticles [SLNs], nanostructured lipid carriers [NLCs], long-circulating liposomes, active targeting liposomes, and multidrug-loaded liposomes) and emulsion systems (including microemulsions, self-emulsion drug delivery systems [SEDDSs], and active targeting microemulsion) to solve the issues of poor solubility in water, low bioavailability, and severe phlebitis, as well as to improve antitumor efficacy. The pharmacokinetics of different drug delivery systems of β-elemene are also summarized. On the other hand, a number of highly active anticancer β-elemene derivatives have been obtained through modification of the structure of β-elemene. This review focuses on the two drug delivery systems and derivatives of β-elemene for cancer therapy.

Cytotoxicity and apoptosis enhancement in breast and cervical cancer cells upon coadministration of mitomycin C and essential oils in nanoemulsion formulations

The present study aimed to solubilize the antineoplastic agent, mitomycin C (MMC), in two nanoemulsions (NEs) consisting of different essential oils (ginger (Gi) and frankincense (Fr)) in order to examine their anticancer activities on the HeLa cervical cancer cells and MCF-7 breast cancer cells. The two NEs-based Gi and Fr oil were produced by a high-pressure homogenization technique followed by solubilizing of the MMC in both NE formulas. The produced formulas were physically characterized by zetasizer and were applied on HeLa and MCF-7 cells at various concentrations for 24 h. The cytotoxicity assays were performed in vitro, using MTT assay, Coomassie blue staining for cellular morphology evaluation, and DAPI fluorescent staining for molecular cell death assessment. The average droplet diameters of the blank NEs have markedly increased and the charges of the droplets were significantly reversed when MMC was loaded. The potential cytotoxicity of the blank and combined formulas on HeLa and MCF-7 cells were dose-dependent and significantly greater than the toxicities of the free MMC. Among the MMC-loaded NE formulas, Fr-MMC has endured the nuclear apoptosis in HeLa cells at a lower concentration and reported the least % of florescence uptake compared to Gi-MMC. In contrast, the combination formula, Gi-MMC, has the strongest apoptotic effect on the MCF-7 cell line since it has the least % florescence uptake compared to the other formulations. Mixing MMC with Gi-NE and Fr-NE has considerably improved its cytotoxicity on the MCF-7 and HeLa cells.

Lipid-polymer hybrid nanocarrier-mediated cancer therapeutics: current status and future directions

The new generation of nanoparticles (NPs) encompass attributes of lipids and polymers and are referred to as 'lipid-polymer hybrid nanoparticles' (LPHNPs). LPHNPs have helped shed light on the mechanisms involved in targeted and non-specific drug delivery. Research has also highlighted the opportunities and challenges faced by the use of nanomedicine as personalized therapies in oncology. Here, we review the development of LPHNPs as cancer therapeutics, focusing on the methods deployed for enhancing the targeting efficiency and applications of LPHNPs.

Importance of integrating nanotechnology with pharmacology and physiology for innovative drug delivery and therapy - an illustration with firsthand examples

Nanotechnology has been applied extensively in drug delivery to improve the therapeutic outcomes of various diseases. Tremendous efforts have been focused on the development of novel nanoparticles and delineation of the physicochemical properties of nanoparticles in relation to their biological fate and functions. However, in the design and evaluation of these nanotechnology-based drug delivery systems, the pharmacology of delivered drugs and the (patho-)physiology of the host have received less attention. In this review, we discuss important pharmacological mechanisms, physiological characteristics, and pathological factors that have been integrated into the design of nanotechnology-enabled drug delivery systems and therapies. Firsthand examples are presented to illustrate the principles and advantages of such integrative design strategies for cancer treatment by exploiting 1) intracellular synergistic interactions of drug-drug and drug-nanomaterial combinations to overcome multidrug-resistant cancer, 2) the blood flow direction of the circulatory system to maximize drug delivery to the tumor neovasculature and cells overexpressing integrin receptors for lung metastases, 3) endogenous lipoproteins to decorate nanocarriers and transport them across the blood-brain barrier for brain metastases, and 4) distinct pathological factors in the tumor microenvironment to develop pH- and oxidative stress-responsive hybrid manganese dioxide nanoparticles for enhanced radiotherapy. Regarding the application in diabetes management, a nanotechnology-enabled closed-loop insulin delivery system was devised to provide dynamic insulin release at a physiologically relevant time scale and glucose levels. These examples, together with other research results, suggest that utilization of the interplay of pharmacology, (patho-)physiology and nanotechnology is a facile approach to develop innovative drug delivery systems and therapies with high efficiency and translational potential.

Lipid-polymer hybrid nanocarriers for delivering cancer therapeutics

Cancer remained a major cause of death providing diversified challenges in terms of treatment including non-specific toxicity, chemoresistance and relapse. Nanotechnology- based delivery systems grabbed tremendous attention for delivering cancer therapeutics as they provide benefits including controlled drug release, improved biological half-life, reduced toxicity and targeted delivery. Majority of the nanocarriers consists of either a polymer or a lipid component along with other excipients to stabilize the colloidal system. Lipid-based systems provide advantages like better entrapment efficiency, scalability and low- cost raw materials, however, suffer from limitations including instability, a burst release of the drug, and limited surface functionalization. On the other hand, polymeric systems provide an excellent diversity of chemical modifications, stability, controlled release, however limited drug loading capacities and scale up limit their use. Hybrid nanocarriers consisting of lipid and polymer were able to overcome some of these disadvantages while retaining the advantages of both the systems. Designing a stable lipid-polymer hybrid system requires a thorough understanding of the material properties and their behavior in in vitro and in vivo environments. This review highlights the current status and future prospects of lipid-polymer hybrid systems with a particular focus on cancer nanotherapeutics.

Ratiometric drug delivery using non-liposomal nanocarriers as an approach to increase efficacy and safety of combination chemotherapy

The observation that different drug ratios of the same drug combination can lead to synergistic or antagonistic effects when tested against the same cancer cell line in vitro gave rise to a new trend, the ratiometric delivery. This strategy consists of co-encapsulating a specific synergistic ratio of a drug combination into a nanocarrier so that synergism observed in vitro will be faithfully translated to in vivo, optimizing combination therapy. In this review we focus on how to quantify synergism in vitro, followed by how this affected the evolution of nanocarriers culminating in the ratiometric delivery, and finally we summarize the results of the non-liposomal formulations that were built upon this concept.

Sample Extraction and Simultaneous Chromatographic Quantitation of Doxorubicin and Mitomycin C Following Drug Combination Delivery in Nanoparticles to Tumor-bearing Mice

Combination chemotherapy is frequently used in the clinic for cancer treatment; however, associated adverse effects to normal tissue may limit its therapeutic benefit. Nanoparticle-based drug combination has been shown to mitigate the problems encountered by free drug combination therapy. Our previous studies have shown that the combination of two anticancer drugs, doxorubicin (DOX) and mitomycin C (MMC), produced a synergistic effect against both murine and human breast cancer cells in vitro. DOX and MMC co-loaded polymer-lipid hybrid nanoparticles (DMPLN) bypassed various efflux transporter pumps that confer multidrug resistance and demonstrated enhanced efficacy in breast tumor models. Compared to conventional solution forms, such superior efficacy of DMPLN was attributed to the synchronized pharmacokinetics of DOX and MMC and increased intracellular drug bioavailability within tumor cells enabled by the nanocarrier PLN. To evaluate the pharmacokinetics and bio-distribution of co-administered DOX and MMC in both free solution and nanoparticle forms, a simple and efficient multi-drug analysis method using reverse-phase high performance liquid chromatography (HPLC) was developed. In contrast to previously reported methods that analyzed DOX or MMC individually in the plasma, this new HPLC method is able to simultaneously quantitate DOX, MMC and a major cardio-toxic DOX metabolite, doxorubicinol (DOXol), in various biological matrices (e.g., whole blood, breast tumor, and heart). A dual fluorescent and ultraviolet absorbent probe 4-methylumbelliferone (4-MU) was used as an internal standard (I.S.) for one-step detection of multiple drug analysis with different detection wavelengths. This method was successfully applied to determine the concentrations of DOX and MMC delivered by both nanoparticle and solution approaches in whole blood and various tissues in an orthotopic breast tumor murine model. The analytical method presented is a useful tool for pre-clinical analysis of nanoparticle-based delivery of drug combinations.

Diruthenium(ii,iii) metallodrugs of ibuprofen and naproxen encapsulated in intravenously injectable polymer-lipid nanoparticles exhibit enhanced activity against breast and prostate cancer cells

A unique class of diruthenium(ii,iii) metallodrugs containing non-steroidal anti-inflammatory drug (NSAID), Ru₂(NSAID), have been reported to show anticancer activity in glioma models in vitro and in vivo. This work reports the encapsulation of the lead metallodrug of ibuprofen (HIbp), [Ru₂(Ibp)₄Cl] or RuIbp, and also of the new analogue of naproxen (HNpx), [Ru₂(Npx)₄Cl] or RuNpx, in novel intravenously (i.v.) injectable solid polymer-lipid nanoparticles (SPLNs). A rationally selected composition of lipids/polymers rendered nearly spherical Ru₂(NSAID)-SPLNs with a mean size of 120 nm and zeta potential of about -20 mV. The Ru₂(NSAID)-SPLNs are characterized by spectroscopic techniques and the composition in terms of ruthenium-drug species is analyzed by mass spectrometry. The metallodrug-loaded nanoparticles showed high drug loading (17-18%) with ∼100% drug loading efficiency, and good colloidal stability in serum at body temperature. Fluorescence-labeled SPLNs were taken up by the cancer cells in a time- and energy-dependent manner as analyzed by confocal microscopy and fluorescence spectrometry. The Ru₂(NSAID)-SPLNs showed enhanced cytotoxicity (IC₅₀ at 60-100 μmol L^-1 ) in relation to the corresponding Ru₂(NSAID) metallodrugs in breast (EMT6 and MDA-MB-231) and prostate (DU145) cancer cells in vitro. The cell viability of both metallodrug nanoformulations is also compared with those of the parent NSAIDs, HIbp and HNpx, and their corresponding NSAID-SPLNs. In vivo and ex vivo fluorescence imaging revealed good biodistribution and high tumor accumulation of fluorescence-labeled SPLNs following i.v. injection in an orthotopic breast tumor model. The enhanced anticancer activity of the metallodrug-loaded SPLNs in these cell lines can be associated with the advantages of the nanoformulations, assigned mainly to the stability of the colloidal nanoparticles suitable for i.v. injection and enhanced cellular uptake. The findings of this work encourage future in vivo efficacy studies to further exploit the potential of the novel Ru₂(NSAID)-SPLN nanoformulations for clinical application.

Dual-targeted hybrid nanoparticles of synergistic drugs for treating lung metastases of triple negative breast cancer in mice

Lung metastasis is the major cause of death in patients with triple negative breast cancer (TNBC), an aggressive subtype of breast cancer with no effective therapy at present. It has been proposed that dual-targeted therapy, ie, targeting chemotherapeutic agents to both tumor vasculature and cancer cells, may offer some advantages. The present work was aimed to develop a dual-targeted synergistic drug combination nanomedicine for the treatment of lung metastases of TNBC. Thus, Arg-Gly-Asp peptide (RGD)-conjugated, doxorubicin (DOX) and mitomycin C (MMC) co-loaded polymer-lipid hybrid nanoparticles (RGD-DMPLN) were prepared and characterized. The synergism between DOX and MMC and the effect of RGD-DMPLN on cell morphology and cell viability were evaluated in human MDA-MB-231 cells in vitro. The optimal RGD density on nanoparticles (NPs) was identified based on the biodistribution and tumor accumulation of the NPs in a murine lung metastatic model of MDA-MB-231 cells. The microscopic distribution of RGD-conjugated NPs in lung metastases was examined using confocal microscopy. The anticancer efficacy of RGD-DMPLN was investigated in the lung metastatic model. A synergistic ratio of DOX and MMC was found in the MDA-MB-231 human TNBC cells. RGD-DMPLN induced morphological changes and enhanced cytotoxicity in vitro. NPs with a median RGD density showed the highest accumulation in lung metastases by targeting both tumor vasculature and cancer cells. Compared to free drugs, RGD-DMPLN exhibited significantly low toxicity to the host, liver and heart. Compared to non-targeted DMPLN or free drugs, administration of RGD-DMPLN (10 mg/kg, iv) resulted in a 4.7-fold and 31-fold reduction in the burden of lung metastases measured by bioluminescence imaging, a 2.4-fold and 4.0-fold reduction in the lung metastasis area index, and a 35% and 57% longer median survival time, respectively. Dual-targeted RGD-DMPLN, with optimal RGD density, significantly inhibited the progression of lung metastasis and extended host survival.

PNC27 anticancer peptide as targeting ligand significantly improved antitumor efficacy of Doxil in HDM2-expressing cells

Aim: To investigate the potential of PNC27 peptide, 12–26 of p53 with high affinity for HDM2 protein, as targeting ligand for Doxil to improve its antitumor activity. Materials & methods: Doxil postinserted with 25, 50, 100 and 200 PNC27 peptides per liposome. Flow cytometry and confocal analysis were performed on C26 colon carcinoma (HDM2 positive) and B16F0 melanoma (HDM2 negative) cells. In vivo studies were performed on BALB/c mice bearing C26 and C57BL/6 mice bearing B16F0 tumor models. Results: PNC27–Doxil showed significant cellular uptake and cytotoxicity in C26 cells compared with Doxil. PNC27–Doxil (100 PNC27 peptide) significantly improved therapeutic efficacy of Doxil without compromising its biodistribution in C26 tumor. However, these results were not observed in B16F0 cells. Conclusion: PNC27 is a promising targeting ligand for Doxil against HDM2-positive cancers.

Design of nanocarriers for nanoscale drug delivery to enhance cancer treatment using hybrid polymer and lipid building blocks

Polymer-lipid hybrid nanoparticles (PLN) are an emerging nanocarrier platform made from building blocks of polymers and lipids. PLN integrate the advantages of biomimetic lipid-based nanoparticles (i.e. solid lipid nanoparticles and liposomes) and biocompatible polymeric nanoparticles. PLN are constructed from diverse polymers and lipids and their numerous combinations, which imparts PLN with great versatility for delivering drugs of various properties to their nanoscale targets. PLN can be classified into two types based on their hybrid nanoscopic structure and assembly methods: Type-I monolithic matrix and Type-II core-shell systems. This article reviews the history of PLN development, types of PLN, lipid and polymer candidates, fabrication methods, and unique properties of PLN. The applications of PLN in delivery of therapeutic or imaging agents alone or in combination for cancer treatment are summarized and illustrated with examples. Important considerations for the rational design of PLN for advanced nanoscale drug delivery are discussed, including selection of excipients, synthesis processes governing formulation parameters, optimization of nanoparticle properties, improvement of particle surface functionality to overcome macroscopic, microscopic and cellular biological barriers. Future directions and potential clinical translation of PLN are also suggested.

Nanomedicine of synergistic drug combinations for cancer therapy - Strategies and perspectives

Nanomedicine of synergistic drug combinations has shown increasing significance in cancer therapy due to its promise in providing superior therapeutic benefits to the current drug combination therapy used in clinical practice. In this article, we will examine the rationale, principles, and advantages of applying nanocarriers to improve anticancer drug combination therapy, review the use of nanocarriers for delivery of a variety of combinations of different classes of anticancer agents including small molecule drugs and biologics, and discuss the challenges and future perspectives of the nanocarrier-based combination therapy. The goal of this review is to provide better understanding of this increasingly important new paradigm of cancer treatment and key considerations for rational design of nanomedicine of synergistic drug combinations for cancer therapy.

Self-Assembling Doxorubicin Prodrug Forming Nanoparticles and Effectively Reversing Drug Resistance In Vitro and In Vivo

Doxorubicin (DOX) is a widely used chemotherapeutic drug to treat a range of cancers. However, its unfavorable effects, particularly the cardiotoxicity and the induction of multidrug resistance (MDR), significantly limit its clinical applications. Herein, a novel doxorubicin prodrug, PEG_2K -DOX, is synthesized by conjugating a deprotonated doxorubicin molecule with the polyethylene glycol (PEG, MW: 2K) chain via pH-responsive hydrazone bond, and its potential as a better alternative than doxorubicin is evaluated. The data show that the amphiphilic PEG_2K -DOX can self-assemble into stable nanoparticles with a high and fixed doxorubicin loading content (≈20 wt%), a favorable size of 91.5 nm with a narrow polydispersity (PDI = 0.14), good stability, and pH-dependent release behavior due to the acid-cleavable linkage between PEG and doxorubicin. Although doxorubicin hardly accumulates in MDR cells, PEG_2K -DOX nanoparticles significantly increase the cellular uptake and cell-killing activity of doxorubicin in two MDR cancer cell lines MCF-7/ADR and KBv200, with the IC₅₀ values dropped to 1.130% and 42.467% of doxorubicin, respectively. More impressively, PEG_2K -DOX nanoparticles exhibit significantly improved plasma pharmacokinetics, increased in vivo therapeutic efficacy against MDR xenograft tumors, and better in vivo safety compared with doxorubicin. PEG_2K -DOX nanoparticles hold the promise to become a better alternative than doxorubicin for cancer treatment, especially for MDR tumors.

NANOMEDICINE: will it offer possibilities to overcome multiple drug resistance in cancer?

This review is written with the purpose to review the current nanomedicine literature and provide an outlook on the developments in utilizing nanoscale drug constructs in treatment of solid cancers as well as in the potential treatment of multi-drug resistant cancers. No specific design principles for this review have been utilized apart from our active choice to avoid results only based on in vitro studies. Few drugs based on nanotechnology have progressed to clinical trials, since most are based only on in vitro experiments which do not give the necessary data for the research to progress towards pre-clinical studies. The area of nanomedicine has indeed spark much attention and holds promise for improved future therapeutics in the treatment of solid cancers. However, despite much investment few targeted therapeutics have successfully progressed to early clinical trials, indicating yet again that the human body is complicated and that much more understanding of the fundamentals of receptor interactions, physics of nanomedical constructs and their circulation in the body is indeed needed. We believe that nanomedical therapeutics can allow for more efficient treatments of resistant cancers, and may well be a cornerstone for RNA based therapeutics in the future given their general need for shielding from the harsh environment in the blood stream.

Polymer-lipid hybrid nanoparticles synchronize pharmacokinetics of co-encapsulated doxorubicin-mitomycin C and enable their spatiotemporal co-delivery and local bioavailability in breast tumor

Effective combination chemotherapy requires the delivery of drugs of synergism to tumor sites while sparing normal tissues. Herein we investigated whether coencapsulation of doxorubicin and mitomycin C within polymer-lipid hybrid nanoparticles (DMPLN) achieved this goal via ratiometric drugs in an orthotopic murine breast tumor model with nanocarrier-modified biodistribution, pharmacokinetics, local bioavailability and toxicity. Fluorescence imaging revealed quickened and extended tumor uptake but reduced cardiac accumulation of DMPLN. Quantitative drug analysis demonstrated prolonged systemic circulation, increased tumor accumulation and sustained synergistic ratios of doxorubicin and mitomycin C delivered by DMPLN over 24h. Higher levels of tumor cell apoptosis and reduced organ toxicity were obtained with DMPLN compared to free drug cocktails. DMPLN released DOX in tumors more efficiently than that from liposomal doxorubicin, as evidenced by a higher extent of the metabolite, doxorubicinol. These findings substantiate the importance of rational design of nanoparticles for synergistic drug combination therapy.

FROM THE CLINICAL EDITOR

The treatment of cancer usually involves using combination chemotherapeutic agents. In adopting a nanomedicine approach, one can in theory design combination therapy consisting of drugs of synergistic activities, with the aim to target tumor specifically while minimizing systemic toxicity. The authors in this study provided evidence for this rational design by co-encapsulation of doxorubicin and mitomycin C within polymer-lipid hybrid nanoparticles (DMPLN) in a breast cancer model.

Engineered Nanoparticles Against MDR in Cancer: The State of the Art and its Prospective

Cancer is a highly heterogeneous disease at intra/inter patient levels and known as the leading cause of death worldwide. A variety of mono and combinational therapies including chemotherapy have been evolved over the years for its effective treatment. However, advent of chemotherapeutic resistance or multidrug resistance (MDR) in cancer is a major challenge researchers are facing in cancer chemotherapy. MDR is a complex process having multifaceted non-cellular or cellular-based mechanisms. Research in the area of cancer nanotechnology over the past two decade has now proven that the smartly designed nanoparticles help in successful chemotherapy by overcoming the MDR and preferentially accumulate in the tumor region by means of active and passive targeting therefore reducing the offtarget accumulation of payload. Many of such nanoparticles are in different stages of clinical trials as nanomedicines showing promising result in cancer therapy including the resistant cases. Nanoparticles as chemotherapeutics carriers offer the opportunity to have multiple payload of drug and or imaging agents for combinational and theranostics therapy. Moreover, nanotechnology further bring in notice the new treatment strategies such as combining the NIR, MRI and HIFU in cancer chemotherapy and imaging. Here, we discussed the cellular/non-cellular factors constituting the MDR in cancer and the role of nanomedicines in effective chemotherapy of MDR cases of cancers. Moreover, recent advancements like combinational payload delivery and combined physical approach with nanotechnology in cancer therapy have also been discussed.

How can nanomedicines overcome cellular-based anticancer drug resistance?

This review discusses the mechanisms of anticancer drug resistance according to its cellular level of action and outlines the nanomedicine-based strategies adopted to overcome it.

Targeting cancer cells in the tumor microenvironment: opportunities and challenges in combinatorial nanomedicine

Cancer therapies of the future will rely on synergy between drugs delivered in combination to achieve both maximum efficacy and decreased toxicity. Nanoscale drug delivery vehicles composed of highly tunable nanomaterials ('nanocarriers') represent the most promising approach to achieve simultaneous, cell-selective delivery of synergistic ratios of combinations of drugs within solid tumors. Nanocarriers are currently being used to co-encapsulate and deliver synergistic ratios of multiple anticancer drugs to target cells within solid tumors. Investigators exploit the unique environment associated with solid tumors, termed the tumor microenvironment (TME), to make 'smart' nanocarriers. These sophisticated nanocarriers exploit the pathological conditions in the TME, thereby creating highly targeted nanocarriers that release their drug payload in a spatially and temporally controlled manner. The translational and commercial potential of nanocarrier-based combinatorial nanomedicines in cancer therapy is now a reality as several companies have initiated human clinical trials.