CXCR4 Targeting Nanoplatform for Transcriptional Activation of Latent HIV-1 Infected T Cells.

Antiretroviral drugs are limited in their ability to target latent retroviral reservoirs in CD4+ T cells, highlighting the need for a T cell-targeted drug delivery system that activates the transcription of inactivated viral DNA in infected cells. Histone deacetylase inhibitors (HDACi) disrupt chromatin-mediated silencing of the viral genome and are explored in HIV latency reversal. But single drug formulations of HDACi are insufficient to elicit therapeutic efficacy, warranting combination therapy. Furthermore, protein kinase C activators (PKC) have shown latency reversal activity in HIV by activating the NF-κB signaling pathway. Combining HDACi (SAHA) with PKC (PMA) activators enhances HIV reservoir activation by promoting chromatin decondensation and subsequent transcriptional activation. In this study, we developed a mixed nanomicelle (PD-CR4) drug delivery system for simultaneous targeting of HIV-infected CD4+ T cells with two drugs, suberoylanilide hydroxamic acid (SAHA) and phorbol 12-myristate 13-acetate (PMA). SAHA is a HDACi that promotes chromatin decondensation, while PMA is a PKC agonist that enhances transcriptional activation. The physicochemical properties of the formulated PD-CR4 nanoparticles were characterized by NMR, CMC, DLS, and TEM analyses. Further, we investigated in vitro safety profiles, targeting efficacy, and transcriptional activation of inactivated HIV reservoir cells. Our results suggest that we successfully prepared a targeted PD system with dual drug loading. We have compared latency reversal efficacy of a single drug nanoformulation and combination drug nanoformulation. Final PD-SP-CR4 successfully activated infected CD4+ T cell reservoirs and showed enhanced antigen release from HIV reservoir T cells, compared with the single drug treatment group as expected. To summarize, our data shows PD-SP-CR4 has potential T cell targeting efficiency and efficiently activated dormant CD4+ T cells. Our data indicate that a dual drug-loaded particle has better therapeutic efficacy than a single loaded particle as expected. Hence, PD-CR4 can be further explored for HIV therapeutic drug delivery studies.

Hybrid exosomes, exosome-like nanovesicles and engineered exosomes for therapeutic applications.

Exosomes are endosome-derived nanovesicles involved in cellular communication. They are natural nanocarriers secreted by various cells, making them suitable candidates for diverse drug delivery and therapeutic applications from a material standpoint. They have a phospholipid bilayer decorated with functional molecules and an enclosed parental matrix, which has attracted interest in developing designer/hybrid engineered exosome nanocarriers. The structural versatility of exosomes allows the modification of their original configuration using various methods, including genetic engineering, chemical procedures, physical techniques, and microfluidic technology, to load exosomes with additional cargo for expanded biomedical applications. Exosomes show enormous potential for overcoming the limitations of conventional nanoparticle-based techniques in targeted therapy. This review highlights the exosome sources, characteristics, state of the art in the field of hybrid exosomes, exosome-like nanovesicles and engineered exosomes as potential cargo delivery vehicles for therapeutic applications.

Extracellular vesicles and exosome-like nanovesicles as pioneering oral drug delivery systems.

As extracellular vesicle (EV)-based nanotechnology has developed rapidly, it has made unprecedented opportunities for nanomedicine possible. EVs and exosome-like nanovesicles (ELNVs) are natural nanocarriers with unique structural, compositional, and morphological characteristics that provide excellent physical, chemical, and biochemical properties. In this literature, we examine the characteristics of EVs, including how they are administered orally and their therapeutic activity. According to the current examples of EVs and ELNVs for oral delivery, milk and plant EVs can exert therapeutic effects through their protein, nucleic acid, and lipid components. Furthermore, several methods for loading drugs into exosomes and targeting exosomes have been employed to investigate their therapeutic capability. Moreover, we discuss EVs as potential drug carriers and the potential role of ELNVs for disease prevention and treatment or as potential drug carriers in the future. In conclusion, the issues associated with the development of EVs and ELNVs from sources such as milk and plants, as well as concerns with standardized applications of these EVs, are discussed.

Light and immunostimulant mediated in situ re-education of tumor-associated macrophages using photosensitizer conjugated mannan nanoparticles for boosting immuno-photodynamic anti-metastasis therapy.

In an immunosuppressive tumor microenvironment, tumor-associated macrophages (TAMs) are the most abundant cells displaying pro-tumorigenic M2-like phenotypes, encouraging tumor growth and influencing the development of resistance against conventional therapies. TAMs are highly malleable. They can be repolarized into tumoricidal M1-like cells. In this study, we report the synthesis of novel co-operative immuno-photodynamic nanoparticles involving TAM self-targeting acrylic acid grafted mannan (a polysaccharide) conjugated with the chlorin e6 (Ce6) photosensitizer and then loaded with resiquimod (R848), a toll-like receptor (TLR7/8) agonist. The mannan conjugated Ce6 loaded with R848 (MCR) as bioconjugate nanoparticles demonstrated selective targeting of anti-inflammatory M2-like cells. Using photodynamic therapy they were repolarized to pro-inflammatory M1-like cells with combined effects of reactive oxygen species (ROS)-triggered intracellular signaling and a small-molecule immunostimulant. The MCR also demonstrated a TAM-directed adaptive immune response, inhibited tumor growth, and prevented metastasis. Our results indicate that these MCR nanoparticles can effectively target TAMs and modulate them for cancer immunotherapy.

Tumor Microenvironment-Regulating Immunosenescence-Independent Nanostimulant Synergizing with Near-Infrared Light Irradiation for Antitumor Immunity.

The combination of photothermal therapy (PTT) and toll-like receptor (TLR)-mediated immunotherapy can elicit antitumor immunity and modulate the immunosuppressive tumor microenvironment (TME). Unlike other TLRs, TLR-5 is a promising target for immune activation, as its expression is well-maintained even during immunosenescence. Here, we developed a unique tumor microenvironment-regulating immunosenescence-independent nanostimulant consisting of TLR-5 adjuvant Vibrio vulnificus flagellin B (FlaB) conjugated onto the surface to an IR 780-loaded hyaluronic acid-stearylamine (HIF) micelles. These HIF micelles induced immune-mediated cell death via PTT when irradiated with a near-infrared laser. In comparison with PTT alone, the combination of in situ-generated tumor-associated antigens produced during PTT and the immune adjuvant FlaB demonstrated enhanced vaccine-like properties and modulated the TME by suppressing immune-suppressive regulatory cells (Tregs) and increasing the fraction of CD103+ migratory dendritic cells, which are responsible for trafficking tumor antigens to draining lymph nodes (DLNs). This combinatorial strategy (i.e., applying a TLR-5 adjuvant targeted to immunosenescence-independent TLR-5 and the in situ photothermal generation of tumor-associated antigens) is a robust system for next-generation immunotherapy and could even be applied in elderly patients, thus broadening the clinical scope of immunotherapy strategies.

Self-assembled heptamethine cyanine dye dimer as a novel theranostic drug delivery carrier for effective image-guided chemo-photothermal cancer therapy.

Near-infrared (NIR)-induced dye-based theranostic drug delivery carriers are used for critical image-guided chemo-photothermal cancer therapy. However, most carriers fail to deliver sufficient heat and fluorescence efficiently due to direct π-π stacking of the aromatic rings of the NIR dye and drug. In the work reported herein, we examined a self-assembled heptamethine cyanine dye dimer (CyD) with improved heat and fluorescence delivery that was developed by manipulating the unique structural and optical properties of the dimer. The H-aggregation of CyD in an aqueous solution generated a great amount of heat by transforming the energy of the excited electrons into non-radiative energy. Moreover, the disulfide bond of CyD assisted nanoparticles with a drug by minimizing the interaction between the NIR dye and drug, and also by releasing the drug in a redox environment. As a result, DOX encapsulated within CyD (CyD/DOX) showed strong heat generation and fluorescence imaging in tumor-bearing mice, allowing detection of the tumor site and inhibition of tumor growth by chemo-photothermal therapy. The multiplicity of features supplied by the newly developed CyD demonstrated the potential of CyD/DOX as an NIR dye-based theranostic drug-delivery carrier for effective chemo-photothermal cancer therapy.

Self-Quenched Polysaccharide Nanoparticles with a Reactive Oxygen Species-Sensitive Cascade for Enhanced Photodynamic Therapy.

Tumor microenvironment (TME)-responsive nanocarrier systems that keep the photosensitizer (PS) inactive during systemic circulation and then efficiently release or activate the PS in response to unique TME conditions have attracted much attention. Herein, we report novel TME-responsive, self-quenched polysaccharide nanoparticles (NPs) with a reactive oxygen species (ROS)-sensitive cascade. The PS, pheophorbide A (PhA), was conjugated to a water-soluble glycol chitosan (GC) through an ROS-sensitive thioketal (TK) linker. The amphiphilic GC-TK-PhA conjugates could arrange themselves into NPs and remain photoinactive due to their self-quenching effects. Upon reaching the ROS-rich hypoxic core of the tumor tissue, the NPs release the PS in a photoactive form by efficient, ROS-sensitive TK bond cleavage, thus generating potent phototoxic effects. Following near-infrared irradiation, the increase in locoregional ROS levels further accelerates the release and activation of PS. These cascade reactions caused a significant reduction in the tumor volume, demonstrating good antitumor potential.

Bioactivatable reactive oxygen species-sensitive nanoparticulate system for chemo-photodynamic therapy.

Bioactivatable polymer nanoparticles (NPs) have attracted considerable attention as a prospective cancer therapy. Herein, we describe bioactivatable reactive oxygen species (ROS)-sensitive prodrug NPs designed to elicit spatiotemporally controlled, phototriggered chemo-photodynamic therapy. First, an effective anticancer agent, doxorubicin (DOX), was conjugated to poly(ethylene glycol) (PEG) via an ROS-responsive degradable thioketal (TK) linker. The resulting amphiphilic PEG-DOX conjugate (PEG-TK-DOX) self-assembled into a bioactivatable ROS-responsive NP system could efficiently encapsulate a hydrophobic photodynamic therapy (PDT) agent, pheophorbide A (PhA), with good colloidal stability and unimodal size distribution. Second, after the selective retention of NPs in the tumor, the site-specific release of DOX and PhA was spatiotemporally controlled, initially by endogenous ROS and subsequently by exogenous ROS produced during PDT. The locoregional treatment not only photoactivates PhA molecules to generate cytotoxic ROS but also triggers an ROS cascade, which accelerates the release of DOX and PhA via the ROS-mediated structural destruction of NPs, resulting in an enhanced anticancer therapeutic effect. This prodrug-NP system may function as an effective nanomedicine platform, working synergistically to maximize the efficacy of the combination of chemotherapy and photodynamic therapy with a remote-controlled release mechanism. STATEMENT OF SIGNIFICANCE: Photodynamic therapy (PDT) is a noninvasive therapy involving local ROS generation through the activation of photosensitizer (PS) molecules induced via external irradiation with near-infrared (NIR) light. Combinational therapies with PDT could synergistically enhance the therapeutic efficacy and overcome the limitations of monotherapy. In this study, we describe bioactivatable reactive oxygen species (ROS)-sensitive prodrug nanoparticles designed to elicit spatiotemporally controlled, photo triggered chemo-photodynamic therapy. Upon accumulation in tumor by enhanced permeation and retention (EPR) effect, the nanoparticles exhibited target-specific release of chemo-drug and photosensitizer in a spatiotemporally controlled cascade manner by endogenous ROS in the initial stage and the excessive production of exogenous ROS during PDT, leading to a further ROS cascade that accelerates the release of therapeutic cargo.

Long circulating photoactivable nanomicelles with tumor localized activation and ROS triggered self-accelerating drug release for enhanced locoregional chemo-photodynamic therapy.

Although chemo-photodynamic therapy demonstrates promising synergetic therapeutic effect in malignant cancers, the currently available nanocarriers offer the limited capabilities for selective toxicity, drug release and tumor penetration. Herein, we developed photoactivatable nanomicelles, which are constructed by self-assembling of poly (ethylene glycol) (PEG)-stearamine (C18) conjugate (PTS) with a ROS-sensitive thioketal linker (TL) and co-loaded with doxorubicin (DOX) and photosensitizer pheophorbide A (PhA), for enhanced locoregional chemo-photodynamic therapy. Upon accumulation in tumor region, the resulting PTS nanomicelles loaded with Dox and PhA (PTS-DP) demonstrated reactive oxygen species (ROS) cascade responsive release of the DOX and PhA loaded inside. Initial intracellular release of DOX and PhA from the PTS-DP was triggered by the intrinsic presence of endogenous ROS within cancer cells. Furthermore, upon laser irradiation on the tumor region, enhanced singlet oxygen (1O2) was generated by PhA released initially in cancer cells, which in turns accelerated the cytoplasmic release of DOX through rapid dissociation of nanomicelles. The gradual elevation of local ROS level generated by light-activated PhA subsequent ROS-triggered release of DOX synergistically inhibited tumor growth and enhances the anti-tumor immunity. Findings of our study suggested that ROS-sensitive PTS nanomicelles could be a promising and innovative nanocarrier for locoregional chemo-photodynamic therapy.

Multimodal Composite Iron Oxide Nanoparticles for Biomedical Applications.

Background: Iron oxide nanoparticles (IONPs) are excellent candidates for biomedical imaging because of unique characteristics like enhanced colloidal stability and excellent in vivo biocompatibility. Over the last decade, material scientists have developed IONPs with better imaging and enhanced optical absorbance properties by tuning their sizes, shape, phases, and surface characterizations. Since IONPs could be detected with magnetic resonance imaging, various attempts have been made to combine other imaging modalities, thereby creating a high-resolution imaging platform. Composite IONPs (CIONPs) comprising IONP cores with polymeric or inorganic coatings have recently been documented as a promising modality for therapeutic applications. Methods: In this review, we provide an overview of the recent advances in CIONPs for multimodal imaging and focus on the therapeutic applications of CIONPs. Result: CIONPs with phototherapeutics, IONP-based nanoparticles are used for theranostic application via imaging guided photothermal therapy. Conclusion: CIONP-based nanoparticles are known for theranostic application, longstanding effects of composite NPs in in vivo systems should also be studied. Once such issues are fixed, multifunctional CIONP-based applications can be extended for theranostics of diverse medical diseases in the future.

Tunable pH and redox-responsive drug release from curcumin conjugated γ-polyglutamic acid nanoparticles in cancer microenvironment.

Tunable pH and redox responsive polymer was prepared using γ-polyglutamic acid (γ-PGA) with linker 3-mercaptopropionic acid (3-MPA) (γ-PGA_SH) via oxidation to obtain redox responsive disulfide (γ-PGA_SS) backbone and adipic acid dihydrazide (ADH) (γ-PGA_SS_ADH) with hydrazide functional group for pH responsiveness. Further curcumin (Cur) was conjugated through hydrazone bond of the γ-PGA_SS_ADH via Schiff base reaction to obtain (γ-PGA_SS_ADH_Cur). The prepared systems were characterized by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, Electrospray ionization quadrupole time-of-flight mass spectrometry (ESI-Qq-TOF-MS/MS) and Solid state nuclear magnetic resonance (SS NMR) techniques. γ-PGA_SS_ADH_Cur formed self-assembled core shell nanoparticles (NPs) in existence of stabilized aqueous medium. γ-PGA_SS_ADH_Cur NPs maintained its stability in physiological condition. NPs tunable Cur release and cytotoxicity were observed for γ-PGA_SS_ADH_Cur NPs in both acidic and redox conditions mimicking the cancer microenvironment. γ-PGA_SS_ADH_Cur NPs uptake study showed via endocytosis mechanism resulted in the lysosomal entrapment of these NPs within the cell. γ-PGA_SS_ADH_Cur NPs exhibited a dual stimuli responsive drug delivery and can be used as a smart and potential drug delivery system in cancer microenvironment.