Advances in Anticancer Protein Delivery Using Micro-/ Nanoparticles

Mitochondrial adaptation in cancer drug resistance: prevalence, mechanisms, and management

Drug resistance represents a major obstacle in cancer management, and the mechanisms underlying stress adaptation of cancer cells in response to therapy-induced hostile environment are largely unknown. As the central organelle for cellular energy supply, mitochondria can rapidly undergo dynamic changes and integrate cellular signaling pathways to provide bioenergetic and biosynthetic flexibility for cancer cells, which contributes to multiple aspects of tumor characteristics, including drug resistance. Therefore, targeting mitochondria for cancer therapy and overcoming drug resistance has attracted increasing attention for various types of cancer. Multiple mitochondrial adaptation processes, including mitochondrial dynamics, mitochondrial metabolism, and mitochondrial apoptotic regulatory machinery, have been demonstrated to be potential targets. However, recent increasing insights into mitochondria have revealed the complexity of mitochondrial structure and functions, the elusive functions of mitochondria in tumor biology, and the targeting inaccessibility of mitochondria, which have posed challenges for the clinical application of mitochondrial-based cancer therapeutic strategies. Therefore, discovery of both novel mitochondria-targeting agents and innovative mitochondria-targeting approaches is urgently required. Here, we review the most recent literature to summarize the molecular mechanisms underlying mitochondrial stress adaptation and their intricate connection with cancer drug resistance. In addition, an overview of the emerging strategies to target mitochondria for effectively overcoming chemoresistance is highlighted, with an emphasis on drug repositioning and mitochondrial drug delivery approaches, which may accelerate the application of mitochondria-targeting compounds for cancer therapy.

Efficient intracellular delivery of p53 protein by engineered protein crystals restores tumor suppressing function in vivo

Direct delivery of proteins into cells holds significant potential for basic research and drug development. However, the poor endosomal escape of conventional delivery strategies remains a challenge, thus limiting the clinical translation of many protein therapeutics. Herein, we report that engineered Cry3Aa protein (Pos3Aa) crystals formed naturally within Bacillus thuringiensis can serve as a vehicle for efficient cytosolic delivery of bioactive proteins. We showed that Pos3Aa-mediated delivery of tumor suppressor p53 protein, a promising therapeutic candidate found to be inactivated in nearly half of human cancers, resulted in the restoration of p53 function in p53-deficient cancer cells, and thereby sensitized them to 5-fluorouracil chemotherapy as demonstrated in in vitro and in vivo models. Our results validate that Pos3Aa crystals can be a robust and effective platform for the cytosolic delivery of effector proteins, and suggest that efficient uptake and endosomal escape could be critical for efficacious p53 protein-based cancer therapy.

Gold nanospheres and nanorods for anti-cancer therapy: comparative studies of fabrication, surface-decoration, and anti-cancer treatments

Various gold nanoparticles have been explored as cancer therapeutics because they can be widely engineered for use as efficient drug carriers and diagnostic agents, and in photo-irradiation therapy. In the current review, we focused on shape-dependent biomedical applications of gold nanoparticles including gold nanospheres and nanorods. Fabrication and functionalization strategies of two different gold nanoparticles for anti-cancer therapy are introduced and the distinguishing performance depending on the shape is discussed to suggest the best carrier shape for specific applications. Moreover, recent advances in anti-cancer immunotherapy using gold nano-carriers are discussed. Thus, this comparative review can be helpful in deciding on suitable shapes and surface-modification strategies for preparing various gold nanoparticle-based therapeutics in anti-cancer therapy.

Targeted Myoglobin Delivery as a Strategy for Enhancing the Sensitivity of Hypoxic Cancer Cells to Radiation

The effectiveness of cancer radiotherapy is frequently hindered by the hypoxia of the tumor microenvironment. Direct delivery of oxygen to hypoxic tumor tissues is an attractive strategy to overcome this hypoxia-associated radioresistance. Herein, we report the generation of submicron-sized particles comprising myoglobin fused to the crystal-forming domain of Cry3Aa protein for the targeted delivery of oxygen to cancer cells. We demonstrate that myoglobin-containing particles were successfully produced in Bacillus thuringiensis with the assistance of the Cry3Aa domain I. Furthermore, these particles could be genetically modified to incorporate the cell penetrating peptide TAT and cell targeting peptide A549.1, resulting in particles that exhibited improved cellular uptake and targeting toward A549 cells. Notably, these myoglobin-containing particles increased the intracellular oxygen levels of A549 cells and thereby sensitized them to radiation. These findings suggest that the targeted delivery of O₂-bound myoglobin could be an effective approach to enhance the efficacy of radiotherapy.

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The N-terminal domain of Cry3Aa can be used to generate sub-micron particles

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Genetic fusion of functional peptides to protein particles targets them to A549 cells

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Myoglobin is an effective oxygen carrier for delivery of O₂ into hypoxic cancer cells

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Targeted myoglobin delivery to hypoxic cancer cells increased their radiosensitivity

Na+/K+ ATPase-targeted delivery to metastatic breast cancer models

In this study, we reported doxorubicin (DOX)-encapsulated nanoparticles (NPs) formulated with biocompatible and biodegradable poly (lactic-co-glycolic acid) (PLGA) and modified with a 13-amino acid peptide (S3) against sodium/potassium (Na⁺/K⁺)-ATPase pump alpha subunit to investigate its potential as antitumor agent. The morphological properties and size dispersity of the prepared nanoparticles were evaluated using scanning electron microscope (SEM) and dynamic light scattering (DLS). The encapsulation efficiency and in vitro release during 7 days were evaluated. Comparative in vitro cytotoxicity experiments demonstrated that the S3-conjugated nanoparticles (S3-PLGA-DOX NPs) had higher antiproliferative activity. Flow cytometry analysis confirmed the enhanced cellular uptake of S3-PLGA-DOX NPs in comparison with PLGA-DOX. In vivo study in 4T1 tumor-bearing BALB/C mice revealed that the S3-functionalized DOX-loaded NPs improved antitumor activity and survival rate of 4T1 tumor bearing mice. In this regard, conjugation of S3 peptide to the surface of DOX-loaded PLGA NPs provides site-specific delivery of DOX, inhibits 4T1 tumor growth in vivo and significantly decreases systemic toxicity. The obtained results suggested that the new (Na⁺/K⁺)-ATPase pump-targeted PLGA NPs as a target-selective delivery system for DOX has great potential for the treatment of breast cancer.

Nanostructured Systems in Advanced Drug Targeting for the Cancer Treatment: Recent Patents

BACKGROUND

Cancer is one of the leading causes of death in the world and it is necessary to develop new strategies for its treatment because most therapies have limited access to many types of tumors, as well as low therapeutic efficacy and high toxicity.

OBJECTIVE

The present research aims to identify recent patents of drug delivery nanostructured systems that may have application in improving cancer treatment.

METHODS

Recent patents regarding the drug delivery nanostructured systems for cancer treatment were obtained from the patent databases of the six main patent offices of the world: United States Patent and Trademark Office, European Patent Office, World Intellectual Property Organization, Japan Patent Office, State Intellectual Property Office of China and Korean Intellectual Property Office.

RESULTS

A total of 1710 patent documents from 1998 to 2017 including "drug delivery nanostructured systems for cancer treatment" were retrieved. The top five countries in patent share were USA, China, South Korea, Canada and Germany. The universities and enterprises of USA had the highest amount of patents followed by institutions from China.

CONCLUSION

There is a strong tendency for the development of new nanostructured systems for the release of drugs; particularly, in recent years, the development of nanoparticles has focused on nanodiscs, gold nanoparticles and immunoliposomes.

Immunoengineering with biomaterials for enhanced cancer immunotherapy

Cancer immunotherapy has recently shown dramatic clinical success inducing durable response in patients of a wide variety of malignancies. Further improvement of the clinical outcome with immune related cancer treatment requests more exquisite manipulation of a patient's immune system with increased immunity against diseases while mitigating the toxicities. To meet this challenge, biomaterials applied to immunoengineering are being developed to achieve tissue- and/or cell-specific immunomodulation and thus could potentially enhance both the efficacy and safety of current cancer immunotherapies. Here, we review the recent advancement in the field of immunoengineering using biomaterials and their applications in promoting different modalities of cancer immunotherapies, with focus on cell-, antibody-, immunomodulator-, and gene-based immune related treatments and their combinations with conventional therapies. Challenges and opportunities are discussed in applying biomaterials engineering strategies in the development of future cancer immunotherapies. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Therapeutic Approaches and Drug Discovery > Emerging Technologies Implantable Materials and Surgical Technologies > Nanomaterials and Implants.

Cytosolic delivery of large proteins using nanoparticle-stabilized nanocapsules

We report an effective intracellular delivery strategy for proteins of high molecular weight using AuNP stabilized capsules. This strategy provides direct delivery to the cytosol, avoiding endosomal entrapment.

Redox-Sensitive and Intrinsically Fluorescent Photoclick Hyaluronic Acid Nanogels for Traceable and Targeted Delivery of Cytochrome c to Breast Tumor in Mice

In spite of their high specificity and potency, few protein therapeutics are applied in clinical cancer therapy owing to a lack of safe and efficacious delivery systems. Here, we report that redox-sensitive and intrinsically fluorescent photoclick hyaluronic acid nanogels (HA-NGs) show highly efficient loading and breast tumor-targeted delivery of cytochrome c (CC). HA-NGs were obtained from hyaluronic acid-graft-oligo(ethylene glycol)-tetrazole (HA-OEG-Tet) via inverse nanoprecipitation and catalyst-free photoclick cross-linking with l-cystine dimethacrylamide (MA-Cys-MA). HA-NGs exhibited a superb CC loading content of up to 40.6 wt %, intrinsic fluorescence (λem = 510 nm), and a small size of ca. 170 nm. Notably, CC-loaded nanogels (CC-NGs) showed a fast glutathione-responsive protein release behavior. Importantly, released CC maintained its bioactivity. MTT assays revealed that CC-NGs were highly potent with a low IC50 of 3.07 μM to CD44+ MCF-7 human breast tumor cells. Confocal microscopy observed efficient and selective internalization of fluorescent HA-NGs into MCF-7 cells. Interestingly, HA-NGs exhibited also effective breast tumor penetration. The therapeutic results demonstrated that CC-NGs effectively inhibited the growth of MCF-7 breast tumor xenografts at a particularly low dose of 80 or 160 nmol CC equiv./kg. Moreover, CC-NGs did not cause any change in mice body weight, corroborating their low systemic side effects. Redox-sensitive and intrinsically fluorescent photoclick hyaluronic acid nanogels have appeared as a "smart" protein delivery nanoplatform enabling safe, efficacious, traceable, and targeted cancer protein therapy in vivo.

In vivo pharmacokinetics, biodistribution and the anti-tumor effect of cyclic RGD-modified doxorubicin-loaded polymers in tumor-bearing mice

In our previous study, we successfully produced and characterized a multifunctional drug delivery system with doxorubicin (RC/GO/DOX), which was based on graphene oxide (GO) and cyclic RGD-modified chitosan (RC). Its characteristics include: pH-responsiveness, active targeting of hepatocarcinoma cells, and efficient loading with controlled drug release. Here, we report the pharmacokinetics, biodistribution, and anti-tumor efficacy of RC/GO/DOX polymers in tumor-bearing nude mice. The objective of this study is to assess its targeting potential for tumors. Pharmacokinetic and biodistribution profiles demonstrated that tumor accumulation of RC/GO/DOX polymers was almost three times higher than the others, highlighting the efficacy of the active targeting strategy. Furthermore, the tumor inhibition rate of RC/GO/DOX polymers was 56.64%, 2.09 and 2.93 times higher than that of CS/GO/DOX polymers (without modification) and the DOX solution, respectively. Anti-tumor efficacy results indicated that the tumor growth was better controlled by RC/GO/DOX polymers than the others. Hematoxylin and eosin (H&E) staining showed remarkable changes in tumor histology. Compared with the saline group, the tumor section from the RC/GO/DOX group revealed a marked increase in the quantity of apoptotic and necrotic cells, and a reduction in the quantity of the blood vessels. Together, these studies show that this new system could be regarded as a suitable form of DOX-based treatment of the hepatocellular carcinoma.

Transformable DNA nanocarriers for plasma membrane targeted delivery of cytokine

Direct delivery of cytokines using nanocarriers holds great promise for cancer therapy. However, the nanometric scale of the vehicles made them susceptible to size-dependent endocytosis, reducing the plasma membrane-associated apoptosis signaling. Herein, we report a tumor microenvironment-responsive and transformable nanocarrier for cell membrane targeted delivery of cytokine. This formulation is comprised of a phospholipase A2 (PLA2) degradable liposome as a shell, and complementary DNA nanostructures (designated as nanoclews) decorated with cytokines as the cores. Utilizing the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) as a model cytokine, we demonstrate that the TRAIL loaded DNA nanoclews are capable of transforming into nanofibers after PLA2 activation. The nanofibers with micro-scaled lengths efficiently present the loaded TRAIL to death receptors on the cancer cell membrane and amplified the apoptotic signaling with reduced TRAIL internalization.

Recent advances of cocktail chemotherapy by combination drug delivery systems

Combination chemotherapy is widely exploited for enhanced cancer treatment in the clinic. However, the traditional cocktail administration of combination regimens often suffers from varying pharmacokinetics among different drugs. The emergence of nanotechnology offers an unparalleled opportunity for developing advanced combination drug delivery strategies with the ability to encapsulate various drugs simultaneously and unify the pharmacokinetics of each drug. This review surveys the most recent advances in combination delivery of multiple small molecule chemotherapeutics using nanocarriers. The mechanisms underlying combination chemotherapy, including the synergistic, additive and potentiation effects, are also discussed with typical examples. We further highlight the sequential and site-specific co-delivery strategies, which provide new guidelines for development of programmable combination drug delivery systems. Clinical outlook and challenges are also discussed in the end.

Development of an itraconazole encapsulated polymeric nanoparticle platform for effective antifungal therapy

Schematic illustration of the construction andin vivotrafficking of ITZ-NPs.

Enzyme-mediated in situ formation of pH-sensitive nanogels for proteins delivery

pH-Sensitive (PEG-b-P(LGA-g-Tyr)) nanogels were fabricated through the enzyme-mediated crosslinking reaction and used to load FITC-BSA for intracellular protein delivery.

Cellular processing and destinies of artificial DNA nanostructures

This review gives a panoramic view of the many DNA nanotechnology applications in cells, mechanistic understanding of how and where their interactions occur and their subsequent outcomes.

Programmable nanomedicine: synergistic and sequential drug delivery systems

Recent developments in nanomedicine for the cancer therapy have enabled programmable delivery of therapeutics by exploiting the stimuli-responsive properties of nanocarriers. These therapeutic systems were designed with the relevant chemical and physical properties that respond to different triggers for enhanced anticancer efficacy, including the reduced development of drug-resistance, lower therapeutic dose, site-specific transport, and spatiotemporally controlled release. This minireview discusses the current advances in programmable nanocarriers for cancer therapy with particular emphasis on synergistic and sequential drug delivery systems.

Engineering DNA scaffolds for delivery of anticancer therapeutics

Engineering DNA nanostructures with programmability in size, shape and surface chemistry holds tremendous promise in biomedical applications. As an emerging platform for drug delivery, DNA nanostructures have been extensively studied for delivering anticancer therapeutics, including small-molecule drug, nucleic acids and proteins. In this mini-review, current advances in utilizing DNA scaffolds as drug carriers for cancer treatment were summarized and future challenges were also discussed.

Furin-mediated sequential delivery of anticancer cytokine and small-molecule drug shuttled by graphene

A cellular protease (furin)-mediated graphene-based nanosystem is developed for co-delivery of a membrane-associated cytokine (tumor-necrosis-factor-related apoptosis-inducing ligand, TRAIL) and an intracellular-acting small-molecule drug (Doxorubicin, DOX). TRAIL and DOX can be sequentially released toward the plasma membrane and nucleus, respectively.