Nanotechnology-based combinational drug delivery: an emerging approach for cancer therapy

Application of dextran as nanoscale drug carriers

Dextran is a kind of biocompatible, nontoxic and nonimmunogenic biological substance that has been widely used in drug-delivery systems. With further research and understanding of dextran and its derivatives, people can more precisely control the sequence of dextran by chemical and biosynthetic methods as needed, and modify various structures to improve the properties of dextran, such as hydrophilicity, hydrophobicity, temperature sensitivity, pH sensitivity and ionic strength sensitivity, which will further expand the application of dextran and its derivatives in drug-delivery systems. Herein, the application of dextran and its derivatives in gene transfection and drug delivery was summarized and analyzed, and the problems were studied. At the same time, its application prospects are forecasted.

Nanoparticle-Mediated Combination Therapy: Two-in-One Approach for Cancer

Cancer represents a group of heterogeneous diseases characterized by uncontrolledgrowth and spread of abnormal cells, ultimately leading to death. Nanomedicine plays a significantrole in the development of nanodrugs, nanodevices, drug delivery systems and nanocarriers. Someof the major issues in the treatment of cancer are multidrug resistance (MDR), narrow therapeuticwindow and undesired side effects of available anticancer drugs and the limitations of anticancerdrugs. Several nanosystems being utilized for detection, diagnosis and treatment such as theranosticcarriers, liposomes, carbon nanotubes, quantum dots, polymeric micelles, dendrimers and metallicnanoparticles. However, nonbiodegradable nanoparticles causes high tissue accumulation andleads to toxicity. MDR is considered a major impediment to cancer treatment due to metastatictumors that develop resistance to chemotherapy. MDR contributes to the failure of chemotherapiesin various cancers, including breast, ovarian, lung, gastrointestinal and hematological malignancies.Moreover, the therapeutic efficiency of anticancer drugs or nanoparticles (NPs) used alone is lessthan that of the combination of NPs and anticancer drugs. Combination therapy has long beenadopted as the standard first-line treatment of several malignancies to improve the clinical outcome.Combination therapy with anticancer drugs has been shown to generally induce synergistic drugactions and deter the onset of drug resistance. Therefore, this review is designed to report andanalyze the recent progress made to address combination therapy using NPs and anticancer drugs.We first provide a comprehensive overview of the angiogenesis and of the different types of NPscurrently used in treatments of cancer; those emphasized in this review are liposomes, polymericNPs, polymeric micelles (PMs), dendrimers, carbon NPs, nanodiamond (ND), fullerenes, carbonnanotubes (CNTs), graphene oxide (GO), GO nanocomposites and metallic NPs used forcombination therapy with various anticancer agents. Nanotechnology has provided the convenienttools for combination therapy. However, for clinical translation, we need continued improvementsin the field of nanotechnology.

Design of Tumor Microenvironment-Responsive Drug-Drug Micelle for Cancer Radiochemotherapy

Concomitant radiochemotherapy is a major therapeutic strategy for treating malignant tumors. However, the greatest challenge is how to improve the therapeutic effect of radiochemotherapy to achieve the proper synergetic chemo-/radiotherapy for the tumor. In this study, ferrocenium (antitumor effect) and nitroimidazole (hypoxic cell radiosensitization) conjugates were synthesized to form amphiphilic ferrocenium-hexane-nitroimidazole (Fe-NI), which can self-assemble in aqueous solution. The Fe-NI micelles successfully encapsulate the hydrophobic chemotherapy drug doxorubicin (DOX) and are modified with hyaluronic acid (HA) by electrostatic interactions to form HA-Fe-NIs-DOX micelles. HA-Fe-NIs-DOX micelles rapidly release DOX under tumor hypoxia and a high glutathione (GSH) environment and achieve a synergetic chemo-/radiotherapy for the tumor based on the properties of nitroimidazoles and ferrocenes. The biodistribution results obtained in vivo reveal an effective accumulation in the tumor. The HA-Fe-NIs-DOX micelles show a significant radiosensitizing effect on the tumors, and the combination of chemotherapy and radiotherapy is realized for the treatment of tumor in vitro and in vivo. These findings illustrate that HA-Fe-NIs micelles are a promising candidate, which enhances the antitumor effects as a DOX delivery system, owing to the synergistic mechanisms of antitumor agents and chemo-/radiotherapy.

Application of polydopamine in tumor targeted drug delivery system and its drug release behavior

Inspired by the bionics of marine mussels, polydopamine (PDA), a new polymer with unique physicochemical properties was discovered. Due to its simple preparation, good biocompatibility, unique drug-loading methods, PDA has attracted tremendous attentions in field of drug delivery and imaging, and the combination of chemotherapy and other therapies or diagnostic methods, such as photothermotherapy (PTT), photoacoustic imaging (PAI), magnetic resonance imaging (MRI), etc. As an excellent drug carrier in tumor targeted drug delivery system, the drug release behavior of drug-loaded PDA-based nanoparticles is also an important factor to be considered in the establishment of drug delivery systems. Therefore, the purpose of this review is to provide a comprehensive overview of the various applications of PDA in tumor targeted drug delivery systems and to gain insight into the release behavior of the drug-loaded PDA-based nanocarriers. A sufficient understanding and discussion of these aspects is expected to provide a better way to design more rational and effective PDA-based tumor nano-targeted delivery systems. Apart from this, the prospects for the future application of PDA in this field and some unique insights are listed at the end of the article.

α-Lipoic acid stabilized DTX/IR780 micelles for photoacoustic/fluorescence imaging guided photothermal therapy/chemotherapy of breast cancer

Micellar nanoparticles have unique advantages as carriers for therapeutic or imaging agents, owing to their smaller size and better penetration of tumors. However, some agents, due to their physical or chemical properties, are difficult to load into micelles. IR780 is one of these agents, and is also a promising near-infrared dye for fluorescence imaging (FI)/photoacoustic imaging (PAI) and cancer photothermal therapy (PTT). Its hydrophobic and high crystallization structure results in limited bioavailability in vivo. It is difficult to load into micelles constructed from an amphiphilic block polymer with relatively low molecular weight. In this study, we use computer simulation and introduce another small biomolecule, α-lipoic acid, into the micelles constructed from a mPEG-PCL copolymer, to lower the energy of molecular interaction between MPEG-PCL and IR780, and expect to enhance the loading capacity of the micelles to IR780. The introduction of α-lipoic acid decreases the energy of molecular interaction between MEPG-PCL and IR780 from -46.18 kJ mol-1 to -196.52 kJ mol-1 and increases the loading capacity and stability of the mPEG-PCL micelles to IR780, which also maintains the loading capacity to DTX. We further construct DTX/IR780 co-loaded mPEG-PCL micelles for FI/PAI dual modal imaging guided PTT/chemotherapy of cancer. By FI and PAI evaluation in vitro and in vivo, we demonstrate that the DTX/IR780 co-loaded micelles can be used as FI and PAI probes. By further evaluating the therapeutic outcome of PTT/chemotherapy co-therapy of breast cancer, we demonstrate that the DTX/IR780 co-loaded mPEG-PCL micelles can serve as promising candidates for FI and PAI guided PTT/chemotherapy of breast cancer.

Novel application of pluronic lecithin organogels (PLOs) for local delivery of synergistic combination of docetaxel and cisplatin to improve therapeutic efficacy against ovarian cancer

The synergistic combination of docetaxel (DTX) and cisplatin (CIS) by local drug delivery with a pluronic lecithin organogel (PLO) to facilitate high drug concentrations at tumor sites and less nonspecific distribution to normal organs is thought to be beneficial in chemotherapy. In this study, using Capryol-90 (C90) with the addition of lecithin as the oil phase was developed to carry DTX, which was then incorporated into a PLO-containing CIS to formulate a dual-drug injectable PLO for local delivery. An optimal PLO composite, P₁₃L_0.15O_1.5, composed of PF127:lecithin:C90 at a 13:0.15:1.5 weight ratio was obtained. The sol-gel transition temperature of P₁₃L_0.15O_1.5 was found to be 33 °C. Tumor inhibition studies illustrated that DTX/CIS-loaded P₁₃L_0.15O_1.5 could efficiently suppress tumor growth by both intratumoral and peritumoral injections in SKOV-3 xenograft mouse model. Pharmacokinetic studies showed that subcutaneous administration of P₁₃L_0.15O_1.5 was able to sustain the release of DTX and CIS leading to their slow absorption into the systemic circulation resulting in lower area under the plasma concentration curve at 0-72 h (AUC_0-72) and maximum concentration (C_max) values but longer half-life (T_1/2) and mean residence time (MRT) values. An in vivo biodistribution study showed lower DTX and CIS concentrations in organs compared to other treatment groups after IT administration of the dual drug-loaded P₁₃L_0.15O_1.5. It was concluded that the local co-delivery of DTX and CIS by PLOs may be a promising and effective platform for local anticancer drug delivery with minimal systemic toxicities.

HSA-based multi-target combination therapy: regulating drugs' release from HSA and overcoming single drug resistance in a breast cancer model

Multi-drug delivery systems, which may be promising solution to overcome obstacles, have limited the clinical success of multi-drug combination therapies to treat cancer. To this end, we used three different anticancer agents, Cu(BpT)Br, NAMI-A, and doxorubicin (DOX), to build human serum albumin (HSA)-based multi-drug delivery systems in a breast cancer model to investigate the therapeutic efficacy of overcoming single drug (DOX) resistance to cancer cells in vivo, and to regulate the drugs' release from HSA. The HSA complex structure revealed that NAMI-A and Cu(BpT)Br bind to the IB and IIA sub-domain of HSA by N-donor residue replacing a leaving group and coordinating to their metal centers, respectively. The MALDI-TOF mass spectra demonstrated that one DOX molecule is conjugated with lysine of HSA by a pH-sensitive linker. Furthermore, the release behavior of three agents form HSA can be regulated at different pH levels. Importantly, in vivo results revealed that the HSA-NAMI-A-Cu(BpT)Br-DOX complex not only increases the targeting ability compared with a combination of the three agents (the NAMI-A/Cu(BpT)Br/DOX mixture), but it also overcomes DOX resistance to drug-resistant breast cancer cell lines.

A drug-delivering-drug strategy for combined treatment of metastatic breast cancer

Treatment of metastatic cancer continues to be a huge challenge worldwide. Notably, drug nanocrystals (Ns) in nanosuspensions clearly belong to a type of nanoparticle. Therefore, a question arose as to whether these drug particles can also be applied as carriers for drug delivery. Here, we design a novel paclitaxel (PTX) nanocrystal stabilized with complexes of matrix metalloproteinase (MMP)-sensitive β-casein/marimastat (MATT) for co-delivering MATT and PTX and combined therapy of metastatic breast cancer. The prepared Ns (200 nm) with a drug-loading of >50% were potent in treatment of metastatic cancer, which markedly inhibited MMP expression and activity and greatly blocked the lung metastasis and angiogenesis. In conclusion, employing protein-drug complexes as stabilizers, Ns with dual payloads are developed and are a promising strategy for co-delivery. Furthermore, the developed Ns can target the tumor microenvironment and cancer cells and, as a result, enable efficient treatment for breast metastatic cancer.

Silver nanoparticle functionalized CS-g-(CA-MA-PZA) carrier for sustainable anti-tuberculosis drug delivery

Recently, drug functionalized biodegradable polymers have been appreciated to be imperative to fabricate multi-drug delivery nanosystems for sustainable drug release. In this work, amphiphilic chitosan-grafted-(cetyl alcohol-maleic anhydride-pyrazinamide) (CS-g-(CA-MA-PZA)) was synthesized by multi-step reactions. The incorporation of rifampicin (RF) and entrapment of silver nanoparticles (Ag NPs) on CS-g-(CA-MA-PZA) polymer was carried out by dialysis technique. From the FT-IR experiment, the polymer modification, incorporation of drugs and the entrapment of Ag NPs on micelles were confirmed. The surface morphology of Ag NPs, polymeric system and drug loaded micelles was described by SEM, TEM and AFM techniques. In addition, the controlled release behaviour of CS-g-(CA-MA-PZA) micelles was studied by UV-Vis spectroscopy. In vitro cell viability, cell apoptosis and cellular uptake experiments shows that multi-drug delivery system could enhance the biocompatibility and higher the cytotoxicity effect on the cells. Since the prepared amphiphilic polymeric micelles exhibit spotty features and the system is a promising strategy for a novel candidate for immediate therapeutically effects for alveolar macrophages.

Implication of linker length on cell cytotoxicity, pharmacokinetic and toxicity profile of gemcitabine-docetaxel combinatorial dual drug conjugate

The present study investigates effect of linkers [zero length (without linker), short length linker (glycine and lysine) and long length linker (PEG1000, PEG2000 and PEG3500)] on pharmacokinetics and toxicity of docetaxel (DTX) and gemcitabine (GEM) bio-conjugates. Conjugates were synthesized via carbodiimide chemistry and characterized by ¹H NMR and FTIR. Conjugation of DTX and GEM via linkers showed diverse physiochemical and plasma stability profile. Cellular uptake mechanism in MCF-7 and MDA-MB-231 cell lines revealed clathrin mediated internalization of bio-conjugates developed by using long length linkers, leading to higher cytotoxicity compared with free drug congeners. DTX-PEG3500-GEM and DTX-PEG2000-GEM demonstrated 4.21 and 3.81-fold higher AUC_(0-∞) of GEM in comparison with GEM alone. DTX-PEG2000-GEM and DTX-PEG3500-GEM exhibited reduced hepato-, nephro- and haemolytic toxicity as evident via histopathology, biochemical markers and SEM analysis of RBCs. Conclusively, PEG2000 and PEG3500 significantly improved pharmacokinetics without any sign of toxicity and hence can be explored further for the development of dual-drug conjugates for better therapeutic efficacy.

Upconversion nanocomposite for programming combination cancer therapy by precise control of microscopic temperature

Combinational administration of chemotherapy (CT) and photothermal therapy (PTT) has been widely used to treat cancer. However, the scheduling of CT and PTT and how it will affect the therapeutic efficacy has not been thoroughly investigated. The challenge is to realize the sequence control of these two therapeutic modes. Herein, we design a temperature sensitive upconversion nanocomposite for CT-PTT combination therapy. By monitoring the microscopic temperature of the nanocomposite with upconversion luminescence, photothermal effect can be adjusted to achieve thermally triggered combination therapy with a sequence of CT, followed by PTT. We find that CT administered before PTT results in better therapeutic effect than other administration sequences when the dosages of chemodrug and heat are kept at the same level. This work proposes a programmed method to arrange the process of combination cancer therapy, which takes full advantage of each therapeutic mode and contributes to the development of new cancer therapy strategies.

The combination of chemo and photothermal therapy is widely used to treat cancer but control of chemo and thermal effects is needed for optimized treatment. Here, the authors describe an upconversion nanoparticle which can be used for controlled sequential treatment by controlling laser power.

Photosensitizer Micelles Together with IDO Inhibitor Enhance Cancer Photothermal Therapy and Immunotherapy

The therapeutic outcome of photothermal therapy (PTT) remains impeded by the transparent depth of light. Combining PTT with immunotherapy provides strategies to solve this problem. Regulating metabolism-related enzymes is a promising strategy to stimulate immune response. Here, a nanosystem (NLG919/IR780 micelles) with the properties of photothermal conversion and regulation of the tryptophan metabolic pathway is used to suppress the growth of the tumor margin beyond effective PTT and promote tumor PTT and immunotherapy. It is revealed that mild heat treatment promotes the growth of the tumor margin beyond effective PTT for the upregulation of heat shock protein (HSP), indoleamine 2,3-dioxygenase (IDO), and programmed death-ligand 1 (PD-L1). The NLG919/IR780 micelles can effectively inhibit the activity of IDO but do not affect the level of IDO expression. NLG919/IR780 micelles can effectively accumulate in the tumor and can migrate to lymph nodes and the lymphatic system. In vivo antitumor studies reveal that NLG919/IR780 micelles effectively suppress the growth of tumor margin following PTT in primary tumors. NLG919/IR780 micelle-mediated PTT and IDO inhibition further stimulate the activation of T lymphocytes, inhibiting the growth of distal tumors (abscopal effect). The results demonstrate that the NLG919/IR780 micelles combine PTT and immunotherapy and suppress the tumor margin as well as distal tumor growth post photothermal therapy.

Dual-target cancer theranostic for glutathione S-transferase and hypoxia-inducible factor-1α inhibition

We developed a dual-target theranostic F₆₇₁, which could exhibit synergetic anticancer effects for inhibiting the activities of glutathione S-transferase and the accumulation of hypoxia inducible factor-1α. F₆₇₁ undergoes self-immolative cleavage when exposed to GSTP1-1 in live cancer cells, facilitating the visualization of molecule release and distribution, as well as confirming the autophagy-induced apoptosis.

Combination therapy in combating cancer

Combination therapy, a treatment modality that combines two or more therapeutic agents, is a cornerstone of cancer therapy. The amalgamation of anti-cancer drugs enhances efficacy compared to the mono-therapy approach because it targets key pathways in a characteristically synergistic or an additive manner. This approach potentially reduces drug resistance, while simultaneously providing therapeutic anti-cancer benefits, such as reducing tumour growth and metastatic potential, arresting mitotically active cells, reducing cancer stem cell populations, and inducing apoptosis. The 5-year survival rates for most metastatic cancers are still quite low, and the process of developing a new anti-cancer drug is costly and extremely time-consuming. Therefore, new strategies that target the survival pathways that provide efficient and effective results at an affordable cost are being considered. One such approach incorporates repurposing therapeutic agents initially used for the treatment of different diseases other than cancer. This approach is effective primarily when the FDA-approved agent targets similar pathways found in cancer. Because one of the drugs used in combination therapy is already FDA-approved, overall costs of combination therapy research are reduced. This increases cost efficiency of therapy, thereby benefiting the “medically underserved”. In addition, an approach that combines repurposed pharmaceutical agents with other therapeutics has shown promising results in mitigating tumour burden. In this systematic review, we discuss important pathways commonly targeted in cancer therapy. Furthermore, we also review important repurposed or primary anti-cancer agents that have gained popularity in clinical trials and research since 2012.

Co-delivery of docetaxel and gemcitabine using PEGylated self-assembled stealth nanoparticles for improved breast cancer therapy

The present report deals with conjugation of dual drug; docetaxel (DTX) and gemcitabine (GEM) with linker poly-ethylene-glycol (PEG) to develop amphiphilic molecule having self-assembled property. The synthesized conjugate (DTX-PEG-GEM) demonstrated critical micelle concentration (CMC) in the range of 5-10 μg/ml which self-assembled to form NPs with size 124.2 ± 5.7. Remarkably higher coumarin-6 (C-6) fluorescence signals observed in case of C-6 loaded NPs, suggested enhanced cellular uptake via clathrin mediated endocytosis. Developed NPs demonstrated 4.8-fold higher AUC_(0-∞) value of GEM in comparison with Gemzar®. Tumor growth inhibition study demonstrated significant reduction in tumor volume and higher survival rate with NPs. Moreover, NPs demonstrated significantly lower hepato- and nephro-toxicity, evident from both histopathological sections and biochemical markers level estimation, and hemolytic toxicity. Data in hand suggest enhanced therapeutic efficacy and reduced toxicity of developed NPs over conventional drugs, resulting in efficient combinatorial chemotherapeutic-regimen and patient compliance, which is still an unmet task.

Mixed Liposome Approach for Ratiometric and Sequential Delivery of Paclitaxel and Gemcitabine

Paclitaxel (PTX) and gemcitabine (GEM) are often used in combination due to the synergistic anticancer effects. PTX and GEM combination showed a synergistic effect to SKOV-3 cells at a molar ratio of 1 to 1 and in PTX ➔ GEM sequence. Liposomes were explored as a carrier of PTX and GEM combination. We optimized the drug loading in liposomes varying the preparation method and co-encapsulated PTX and GEM in a single liposome preparation maintaining the maximum loading efficiency of each drug. However, drug release kinetics from the co-loaded liposomes (LpPG) was suboptimal because of the detrimental effect of PTX on GEM-release control. Instead, a mixture of LpP and LpG, which were separately optimized according to the desired release kinetics, achieved a greater cytotoxic effect than LpPG, due to the attenuation of GEM release relative to PTX. This study illustrates that co-encapsulation in a single carrier is not always desirable for the delivery of drug combinations, when the activity depends on the dosing sequence. These combinations may benefit from the mixed liposome approach, which offers greater flexibility in controlling the ratio and release kinetics of component drugs.

Biodegradable MoOx nanoparticles with efficient near-infrared photothermal and photodynamic synergetic cancer therapy at the second biological window

Near-infrared (NIR) laser induced phototherapy has been considered as a noninvasive option for cancer therapy. Herein, we report plasmonic PEGylated molybdenum oxide nanoparticles (PEG-MoO_x NPs) that were synthesized by using a facile hydrothermal method. The PEG-MoO_x NPs exhibit broad absorption at the NIR biological window and remarkable photothermal conversion ability in the first (808 nm) and the second (1064 nm) windows. Moreover, the biocompatible PEG-MoO_x NPs exhibit effective cellular uptake and could be eliminated gradually from the liver and spleen in mice. Studies on the therapeutic effects of these NPs under 808 and 1064 nm exposures with mild hyperthermia are conducted. According to the result, exposure to 1064 nm irradiation can not only effectively convert light into heat but also sensitize the formation of reactive oxygen species (ROS), which exert dramatic cancer cell death and suppression in vivo due to the synergic effect of photothermal therapy (PTT) and photodynamic therapy (PDT). In marked contrast, 808 nm irradiation can only execute limited PTT to cancer cells, showing a relatively low inhibition rate in vitro and in vivo. This biodegradable MoO_x nanoplatform with synergetic PTT and PDT functionalities upon 1064 nm irradiation provided emerging opportunities for the phototherapy of cancer in nanomedicine.

Recent trends of nanomedicinal approaches in clinics

Nanotechnology has become the indispensable cutting edge science providing solutions to many problems associated with human being. The application of nanotechnology associated to human health "nanomedicine" has revolutionized the drug delivery system by providing improved pharmacological and therapeutic properties of drugs. These advantageous effects of drug loaded nanocarrier systems are embraced by the pharmaceutical industries for the development of different effective nanocarriers. Currently, several drug loaded nanoformulations are approved by the Food and Drug Administration (FDA), and some of them are undergoing clinical trials for the human use. In this review, we have discussed the progress achieved so far for various drug loaded nanoformulations along with few emerging nanoformulations that are about to enter into clinical trials.

Nanotheranostics: Emerging Strategies for Early Diagnosis and Therapy of Brain Cancer

Nanotheranostics have demonstrated the development of advanced platforms that can diagnose brain cancer at early stages, initiate first-line therapy, monitor it, and if needed, rapidly start subsequent treatments. In brain nanotheranostics, therapeutic as well as diagnostic entities are loaded in a single nanoplatform, which can be further developed as a clinical formulation for targeting various modes of brain cancer. In the present review, we concerned about theranostic nanosystems established till now in the research field. These include gold nanoparticles, carbon nanotubes, magnetic nanoparticles, mesoporous silica nanoparticles, quantum dots, polymeric nanoparticles, upconversion nanoparticles, polymeric micelles, solid lipid nanoparticles and dendrimers for the advanced detection and treatment of brain cancer with advanced features. Also, we included the role of three-dimensional models of the BBB and cancer stem cell concept for the advanced characterization of nanotheranostic systems for the unification of diagnosis and treatment of brain cancer. In future, brain nanotheranostics will be able to provide personalized treatment which can make brain cancer even remediable or at least treatable at the primary stages.

Pendant HDAC inhibitor SAHA derivatised polymer as a novel prodrug micellar carrier for anticancer drugs

Suberoylanilide hydroxamic acid (SAHA), a histone deacetylase inhibitor (HDACi) approved by FDA for the treatment of cutaneous T cell lymphoma, is a promising anticancer drug for various cancers with a unique mode of action. However, it demonstrates limited clinical benefits in solid tumours as a single drug. In order to achieve enhanced and synergistic co-delivery of SAHA and doxorubicin (DOX), a cleavable SAHA-based prodrug polymer (POEG-b-PSAHA), consisting of hydrophilic poly(oligo(ethylene glycol) methacrylate) (POEG) blocks and hydrophobic SAHA segments, has been developed. POEG-b-PSAHA prodrug polymer was able to form spherical micelles with a diameter around 60 nm and well retained the pharmacological activity of SAHA in either inhibiting the proliferation of tumour cells or inducing histone acetylation. DOX formulated in POEG-b-PSAHA-based micelles showed a sustained release profile. DOX-loaded POEG-b-PSAHA exhibited more potent cytotoxicity towards tumour cells than free DOX and DOX loaded in a pharmacologically 'inert' nanocarrier, POEG-b-POM. Consistently, DOX/POEG-b-PSAHA formulation resulted in an improved therapeutic effect in vivo compared to free DOX, Doxil or DOX formulated in POEG-b-POM micelles. These results suggest that SAHA-based prodrug micelles may serve as a dual functional carrier for combination strategies in epigenetic-oriented anticancer therapy.

Erythrocyte-Membrane-Coated Prussian Blue/Manganese Dioxide Nanoparticles as H2O2-Responsive Oxygen Generators To Enhance Cancer Chemotherapy/Photothermal Therapy

Because of the nontargeting release of anticancer drugs, conventional chemotherapy results in serious side effects and poor therapeutic outcomes. In addition, hypoxia situation in the tumor microenvironment also promotes the growth and metastasis of tumors. Multifunctional nanocarriers with stimuli-activation and hypoxia-relieving properties can help overcome some of these limitations. In this study, we have constructed a nanocarrier which is named PBMn-DOX@RBC. A Prussian blue/manganese dioxide (PBMn) nanoparticle is used as an oxygen precursor or catalyzer for H₂O₂ activation, and a red blood cell (RBC) membrane is used to increase the loading capacity of doxorubicin (DOX) and prolong the circulation time in vivo. H₂O₂ is overproduced in tumor tissues and tumor cells. It can be used as a stimulus to activate drug release. In the presence of H₂O₂, the hypoxia inside the tumors is relieved by the administration of PBMn-DOX@RBC. The generated oxygen disrupts the RBC coated on the surface of PBMn, which accelerates the release of DOX. RBCs also prolong the circulation time of the nanometer system in vivo. By combining the photothermal therapy (PTT) and chemotherapy, the tumor growth inhibition mediated by PBMn-DOX@RBC is further enhanced. PBMn-DOX@RBC fulfills the demands to relieve tumor hypoxia and enhance cancer chemotherapy/PTT.

Recent Advances in Nanoparticle-Based Cancer Drug and Gene Delivery

Effective and safe delivery of anticancer agents is among the major challenges in cancer therapy. The majority of anticancer agents are toxic to normal cells, have poor bioavailability, and lack in vivo stability. Recent advancements in nanotechnology provide safe and efficient drug delivery systems for successful delivery of anticancer agents via nanoparticles. The physicochemical and functional properties of the nanoparticle vary for each of these anticancer agents, including chemotherapeutics, nucleic acid-based therapeutics, small molecule inhibitors, and photodynamic agents. The characteristics of the anticancer agents influence the design and development of nanoparticle carriers. This review focuses on strategies of nanoparticle-based drug delivery for various anticancer agents. Recent advancements in the field are also highlighted, with suitable examples from our own research efforts and from the literature.

Sequential Delivery of Doxorubicin and Zoledronic Acid to Breast Cancer Cells by CB[7]-Modified Iron Oxide Nanoparticles

Drug-loaded magnetic nanoparticles were synthesized and used for the sequential delivery of the antiresorptive agent zoledronic acid (Zol) and the cytotoxic drug doxorubicin (Dox) to breast cancer cells (MCF-7). Zol was attached to bare iron oxide nanoparticles (IONPs) via phosphonate coordination to form Z-NPs. The unbound imidazole of Zol was then used to complex the organic macrocycle CB[7] to obtain CZ-NPs. Dox was complexed to the CZ-NPs to form the fully loaded particles (DCZ-NPs), which were stable in solution at 37 °C and physiological pH (7.4). Fluorescence spectroscopy established that Dox is released in solution from DCZ-NPs suddenly (i) when the particles are subjected to magnetically induced heating to 42 °C at low pH (5.0) and (ii) in the presence of glutathione (GSH). Mass spectrometry indicated that Zol is released slowly in solution at low pH after Dox release. Magnetic measurements with a magnetic reader revealed that DCZ-NPs are internalized preferentially by MCF-7 cells versus nonmalignant cells (HEK293). Zol and Dox acted synergistically when delivered by the particles. DCZ-NPs caused a decrease in the viability of MCF-7 cells that was greater than the net decrease caused when the drugs were added to the cells individually at concentrations equivalent to those delivered by the particles. MCF-7 cells were treated with DCZ-NPs and subjected to an alternating magnetic field (AMF) which, with the nanoparticles present, raised the temperature of the cells and triggered the intracellular release of Dox, as indicated by fluorescence activated cell sorting (FACS). The cytotoxic effects of the DCZ-NPs on MCF-7 cells were enhanced 10-fold by AMF-induced heating. DCZ-NPs were also able to completely inhibit MCF-7 cell adhesion and invasion in vitro, indicating the potential of the particles to act as antimetastatic agents. Together these results demonstrate that DCZ-NPs warrant development as a system for combined chemo- and thermo-therapeutic treatment of cancer.

Nanomaterials as nanocarriers: a critical assessment why these are multi-chore vanquisher in breast cancer treatment

Breast cancer is a group of diseases with various subtypes and leads to high mortality throughout the globe. Various conventional techniques are in practice to cure breast cancer but these techniques are linked with various shortcomings. Mostly these treatments are not site directed and cause toxicity towards normal cells. In order to overcome these issues, we need smart system that can deliver anticancer drugs to specific sites. Targeted drug delivery can be achieved via passive or active drug delivery using nanocarriers. This mode of drug delivery is more effective against breast cancer and may help in the reduction of mortality rate. Potentially used nanocarriers for targeted drug delivery belong to organic and inorganic molecules. Various FDA approved nano products are in use to cure breast cancer. However, body's defense system is main limitation for potential use of nano systems. However, this can be overcome by surface modification of nanocarriers. In this review, breast cancer and its types, targeted drug delivery and nanocarriers used to cure breast cancer are discussed. By progressing nanotechnology, we will be able to fight against this life threatening issue and serve the humanity, which is the basic aim of scientific knowledge.

Use of Biocompatible Sorafenib-gold Nanoconjugates for Reversal of Drug Resistance in Human Hepatoblatoma Cells

The present study identifies the potential of highly biocompatible SF-GNP nano-conjugate to enhance the chemotherapeutic response to combat drug resistance in cancer cells. We developed a stable colloidal suspension of sorafenib-gold nanoconjugate (SF-GNP) of <10 nm size in aqueous medium for reverting the cancer drug resistance in SF-resistant HepG2 cells in a 3D ex-vivo model system. In-vivo biocompatibility assay of SF-GNPs showed absence of systemic toxicological effects including hematological, biochemical and histological parameters. More importantly, the histopathological analysis of vital organs such as liver, brain, lung, kidney and heart showed very least or no sign of inflammation, cell infiltration, necrosis, tissue disorganization or fibrotic reactions after intra-peritoneal administration of SF-GNP nanoconjugates in animals. However, SF-GNP nanoconjugates significantly reduced (>80%) the percentage cell survival and the size and number of SF resistant solid tumor colonies of HepG2 cells in 3D model system. The exposure of SF-GNP nanoconjugate to SF resistant HepG2 cell colonies also provided evidence for anti-proliferative effect and reversal of drug resistance by elucidating the molecular regulatory mechanisms of extracellular matrix factor (CD147), tumor growth factor (TGF-β), hepatoma upregulated protein (hURP) and drug transporter (ABCG-2).

Taxane-Grafted Metal-Oxide Nanoparticles as a New Theranostic Tool against Cancer: The Promising Example of Docetaxel-Functionalized Titanate Nanotubes on Prostate Tumors

The combination of anticancer drugs and metal oxide nanoparticles is of great interest in cancer nanomedicine. Here, the development of a new nanohybrid, titanate nanotube-docetaxel (TiONts-DTX) is reported, the two parts of which are conjugated by covalent linkages. Unlike most nanoparticles currently being developed for biomedical purposes, TiONts present a needle-shaped morphology. The surface of TiONts is linked with 3-aminopropyl triethoxysilane and with a hetero-bifunctional polymer (polyethylene glycol) to create well-dispersed and biocompatible nanovectors. The prefunctionalized surface of this scaffold has valuable attachments to graft therapeutic agents (DTX in our case) as well as chelating agents (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) to monitor the nanohybrids. To evaluate drug efficacy, in vitro tests have demonstrated that the association between TiONts and DTX shows cytotoxic activity against a hormone-refractory prostate cancer cell line (22Rv1) whereas TiONts without DTX do not. Finally, the first in vivo tests with intratumoral injections show that more than 70% of TiONts nanovectors are retained within the tumor for at least 7 d. Moreover, tumor growth in mice receiving TiONts-DTX is significantly slower than that in mice receiving free DTX. This nanohybrid can thus become a promising new tool in biomedicine to fight against prostate cancer.

A large-inner-diameter multi-walled carbon nanotube-based dual-drug delivery system with pH-sensitive release properties

A novel dual-drug delivery system (DDDS) for cancer chemotherapy has been established by employing highly purified and mildly oxidized large-inner-diameter multi-walled carbon nanotubes (LID-MWCNTs) as the vector. The LID-MWCNTs were modified with the antitumor drugs, cisplatin (CDDP) and doxorubicin (DOX). CDDP was encapsulated inside the nanotube vectors by a wet-chemical approach while DOX was attached to the external surfaces through non-covalently interaction. The loading efficiencies of CDDP and DOX were as high as 84.56 and 192.67%, respectively. Notably, after CDDP was encapsulated inside the nanotubes, a three-level blocking strategy, which included polyethylene glycol, folic acid and DOX, was employed to block the CDDP exits at different levels. The pH-sensitive release profile of CDDP was demonstrated using a modified characterization method, as well as that of DOX. Finally, the anticancer activity of the DDDS on MCF-7 cells was tested and a synergistic effect was recorded. This work is part of our LID-MWCNTs based drug delivery system studies, and provides a basis for developing a novel comprehensive antitumor treatment that combines chemotherapy and photothermal therapy.

Tri-Needle Coaxial Electrospray Engineering of Magnetic Polymer Yolk-Shell Particles Possessing Dual-Imaging Modality, Multiagent Compartments, and Trigger Release Potential

Particulate platforms capable of delivering multiple actives as well as providing diagnostic features have gained considerable interest over the last few years. In this study, magnetic polymer yolk-shell particles (YSPs) were engineered using a tri-needle coaxial electrospraying technique enabling dual-mode (ultrasonic and magnetic resonance) imaging capability with specific multidrug compartments via an advanced single-step encapsulation process. YSPs comprised magnetic Fe₃O₄ nanoparticles (MNPs) embedded in the polymeric shell, an interfacing oil layer, and a polymeric core (i.e., composite shell-oil interface-polymeric core). The frequency of the ultrasound backscatter signal was modulated through YSP loading dosage, and both T₁- and T₂-weighted magnetic resonance imaging signal intensities were shown to decrease with increasing MNP content (YSP outer shell). Three fluorescent dyes (selected as model probes with varying hydrophobicities) were coencapsulated separately to confirm the YSP structure. Probe release profiles were tuned by varying power or frequency of an external auxiliary magnetic field (AMF, 0.7 mT (LAMF) or 1.4 mT (HAMF)). In addition, an "inversion" phenomenon for the AMF-enhanced drug release process was studied and is reported. A low YSP cytotoxicity (5 mg/mL) and biocompatibility (murine, L929) was confirmed. In summary, magnetic YSPs demonstrate timely potential as multifunctional theranostic agents for dual-imaging modality and magnetically controlled coactive delivery.

Nanomedicine for prostate cancer using nanoemulsion: A review

Prostate cancer (PCa) is a worldwide issue, with burgeoning rise in prevalence, morbidity and mortality. Targeted drug delivery, a long sort solution in this regard using controlled release (CR) - nanocarriers, is still a challenge. There is an emerging criticism that, the challenges are due to less appreciation for the biological barriers and lack of corresponding newer technologies. Over the years, more understanding about the biological barriers has come with the progress in characterization techniques. Correspondingly, there is a change in opinion about approaches in clinical trial that; focus of the end point need to be shifted towards disease stabilization for these explorative technologies. Currently, there is a requirement to overcome these newly identified challenges to develop newer affordable therapeutics. The ongoing clinical protocol for therapy using CR-nanocarriers is intravenous injection followed by local targeting to cancer site. This is the most accepted protocol and new CR-nanocarriers are being developed to suit this protocol. In this review, recent progress in treatment of PCa using CR-nanocarriers is analyzed with respect to newly identified biological barriers and design challenges. Possibilities of exploring nanoemulsion (NE) platform for targeted drug delivery to PCa are examined. Repurposing of drugs and combination therapy using NE platform targeted to PCa can be explored for design and development of affordable nanomedicine. In 20yrs. from now there expected to be numerous affordable nanomedicine technologies available in market exploring these lines.

Nanoformulations for combination or cascade anticancer therapy

Nanoparticle drug formulations have been extensively investigated, developed, and in some cases, approved by the Food and Drug Administration (FDA). Synergistic combinations of drugs having distinct tumor-inhibiting mechanisms and non-overlapping toxicity can circumvent the issue of treatment resistance and may be essential for effective anti-cancer therapy. At the same time, co-delivery of a combined regimen by a single nanocarrier presents a challenge due to differences in solubility, molecular weight, functional groups and encapsulation conditions between the two drugs. This review discusses cellular and microenvironment mechanisms behind treatment resistance and nanotechnology-based solutions for effective anti-cancer therapy. Co-loading or cascade delivery of multiple drugs using of polymeric nanoparticles, polymer-drug conjugates and lipid nanoparticles will be discussed along with lipid-coated drug nanoparticles developed by our lab and perspectives on combination therapy.

Nanomedicine-based combination anticancer therapy between nucleic acids and small-molecular drugs

Anticancer therapy has always been a vital challenge for the development of nanomedicine. Repeated single therapeutic agent may lead to undesirable and severe side effects, unbearable toxicity and multidrug resistance due to complex nature of tumor. Nanomedicine-based combination anticancer therapy can synergistically improve antitumor outcomes through multiple-target therapy, decreasing the dose of each therapeutic agent and reducing side effects. There are versatile combinational anticancer strategies such as chemotherapeutic combination, nucleic acid-based co-delivery, intrinsic sensitive and extrinsic stimulus combinational patterns. Based on these combination strategies, various nanocarriers and drug delivery systems were engineered to carry out the efficient co-delivery of combined therapeutic agents for combination anticancer therapy. This review focused on illustrating nanomedicine-based combination anticancer therapy between nucleic acids and small-molecular drugs for synergistically improving anticancer efficacy.