Engineered tumor-specific T cells using immunostimulatory photothermal nanoparticles.

BACKGROUND: Adoptive T cell therapy (ATCT) has been successful in treating hematological malignancies and is currently under investigation for solid-tumor therapy. In contrast to existing chimeric antigen receptor (CAR) T cell and/or antigen-specific T cell approaches, which require known targets, and responsive to the need for targeting a broad repertoire of antigens in solid tumors, we describe the first use of immunostimulatory photothermal nanoparticles to generate tumor-specific T cells. METHODS: Specifically, we subject whole tumor cells to Prussian blue nanoparticle-based photothermal therapy (PBNP-PTT) before culturing with dendritic cells (DCs), and subsequent stimulation of T cells. This strategy differs from previous approaches using tumor cell lysates because we use nanoparticles to mediate thermal and immunogenic cell death in tumor cells, rendering them enhanced antigen sources. RESULTS: In proof-of-concept studies using two glioblastoma (GBM) tumor cell lines, we first demonstrated that when PBNP-PTT was administered at a "thermal dose" targeted to induce the immunogenicity of U87 GBM cells, we effectively expanded U87-specific T cells. Further, we found that DCs cultured ex vivo with PBNP-PTT-treated U87 cells enabled 9- to 30-fold expansion of CD4+ and CD8+ T cells. Upon co-culture with target U87 cells, these T cells secreted interferon-É£ in a tumor-specific and dose-dependent manner (up to 647-fold over controls). Furthermore, T cells manufactured using PBNP-PTT ex vivo expansion elicited specific cytolytic activity against target U87 cells (donor-dependent 32-93% killing at an effector to target cell (E:T) ratio of 20:1) while sparing normal human astrocytes and peripheral blood mononuclear cells from the same donors. In contrast, T cells generated using U87 cell lysates expanded only 6- to 24-fold and killed 2- to 3-fold less U87 target cells at matched E:T ratios compared with T cell products expanded using the PBNP-PTT approach. These results were reproducible even when a different GBM cell line (SNB19) was used, wherein the PBNP-PTT-mediated approach resulted in a 7- to 39-fold expansion of T cells, which elicited 25-66% killing of the SNB19 cells at an E:T ratio of 20:1, depending on the donor. CONCLUSIONS: These findings provide proof-of-concept data supporting the use of PBNP-PTT to stimulate and expand tumor-specific T cells ex vivo for potential use as an adoptive T cell therapy approach for the treatment of patients with solid tumors.

Photothermal therapies to improve immune checkpoint blockade for cancer.

Immune checkpoint blockade (ICB) comprising monoclonal antibodies (mAbs) against immune 'checkpoints', such as CTLA-4 and the PD1/PDL1 axis have dramatically improved clinical outcomes for patients with cancer. However, ICB by itself has failed to provide benefit in a wide range of solid tumors, where recurrence still occurs with high incidence. These poor response rates may be due to the therapeutic shortcomings of ICB; namely, a lack of cancer-specific cytotoxicity and ability to debulk tumors. To overcome these limitations, effective ICB therapy may require the combination with other complementary therapeutic platforms. Here, we propose that photothermal therapy (PTT) is an ideal therapeutic modality for combination with ICB because it can generate both tumor-specific cytotoxicity and immunogenicity. PTT elicits these specific effects because it is a localized thermal ablation technique that utilizes light-responsive nanoparticles activated by a wavelength-matched laser. While ICB immunotherapy alone improves cancer immunogenicity but does not generate robust antitumor cytotoxicity, nanoparticle-based PTT elicits targeted and controlled cytotoxicity but sub-optimal long-term immunogenicity. Thus, the two platforms offer complementary and potentially synergistic antitumor effects, which will be detailed in this review. We highlight three classes of nanoparticles used as agents of PTT (i.e., metallic inorganic nanoparticles, carbon-based nanoparticles and organic dyes), and illustrate the potential for nanoparticle-based PTT to potentiate the effects of ICB in preclinical models. Through this discussion, we aim to present PTT combined with ICB as a potent synergistic combination treatment for diverse cancer types currently refractory to ICB as well as PTT monotherapies.

Designing Magnetically Responsive Biohybrids Composed of Cord Blood-Derived Natural Killer Cells and Iron Oxide Nanoparticles.

We report the generation of magnetically responsive, cord blood-derived natural killer (NK) cells using iron oxide nanoparticles (IONPs). NK cells are a promising immune cell population for cancer cell therapy as they can target and lyse target tumor cells without prior education. However, NK cells cannot home to disease sites based on antigen recognition, instead relying primarily on external stimuli and chemotactic gradients for transport. Hence, we hypothesized that conjugating IONPs onto the surface of NK cells provides an added feature of magnetic homing to the NK cells, improving their therapeutic function. We describe a robust design for conjugating the IONPs onto the surface of NK cells, which maintains their intrinsic phenotype and function. The conferred magnetic-responsiveness is utilized to improve the cytolytic function of the NK cells for target cells in 2D and 3D models. These findings demonstrate the feasibility of improving NK cell homing and therapeutic efficacy with our NK:IONP "biohybrid".

Ag loaded B-doped-g C3N4 nanosheet with efficient properties for photocatalysis.

Three material engineering strategies in the form of doping (Boron-doping), nanostructuring (nanosheet (NS) formation) and decorating with plasmonic nanoparticles (loading with Ag metal), were integrated to improve the photocatalytic activity of graphitic carbon nitride (gC3N4). Concentrations of B-doping and Ag-loading were optimized to maximize the catalytic performance in the final nanocomposite of Ag-loaded B-doped gC3N4 NS. Combined effect of all three strategies successfully produced over 5 times higher rate towards degradation of organic dye pollutant, when compared to unmodified bulk gC3N4. Detailed characterization results revealed that incorporation of B in gC3N4 matrix reduces the band gap to increase the visible light absorption, while specific surface area is significantly enhanced upon formation of NS. Decoration of Ag nanoparticles (NPs) on B-doped gC3N4 NS assists in fast transfer of photogenerated electrons from gC3N4 to Ag NPs owing to the interfacial electric field across the junctions and thus reduces the recombination process. Investigations on individual strategies revealed that decoration of Ag NPs to induce better charge separation, is the most effective route for enhancing the photocatalytic activity.

Photothermal Therapy Generates a Thermal Window of Immunogenic Cell Death in Neuroblastoma.

A thermal "window" of immunogenic cell death (ICD) elicited by nanoparticle-based photothermal therapy (PTT) in an animal model of neuroblastoma is described. In studies using Prussian blue nanoparticles to administer photothermal therapy (PBNP-PTT) to established localized tumors in the neuroblastoma model, it is observed that PBNP-PTT conforms to the "more is better" paradigm, wherein higher doses of PBNP-PTT generates higher cell/local heating and thereby more cell death, and consequently improved animal survival. However, in vitro analysis of the biochemical correlates of ICD (ATP, high-motility group box 1, and calreticulin) elicited by PBNP-PTT demonstrates that PBNP-PTT triggers a thermal window of ICD. ICD markers are highly expressed within an optimal temperature (thermal dose) window of PBNP-PTT (63.3-66.4 °C) as compared with higher (83.0-83.5 °C) and lower PBNP-PTT (50.7-52.7 °C) temperatures, which both yield lower expression. Subsequent vaccination studies in the neuroblastoma model confirm the in vitro findings, wherein PBNP-PTT administered within the optimal temperature window results in long-term survival (33.3% at 100 d) compared with PBNP-PTT administered within the higher (0%) and lower (20%) temperature ranges, and controls (0%). The findings demonstrate a tunable immune response to heat generated by PBNP-PTT, which should be critically engaged in the administration of PTT for maximizing its therapeutic benefits.

Cord blood natural killer cells expressing a dominant negative TGF-ß receptor: Implications for adoptive immunotherapy for glioblastoma.

Cord blood (CB) natural killer (NK) cells are promising effector cells for tumor immunotherapy but are currently limited by immune-suppressive cytokines in the tumor microenvironment, such as transforming growth factor (TGF-ß). We observed that TGF-ß inhibits expression of activating receptors such as NKG2D and DNAM1 and decreases killing activity against glioblastoma tumor cells through inhibition of perforin secretion. To overcome the detrimental effects of TGF-ß, we engrafted a dominant negative TGF-ß receptor II (DNRII) on CB-derived NK cells by retroviral transduction and evaluated their ability to kill glioblastoma cells in the presence of TGF-ß. After manufacture using Good Manufacturing Practice-compliant methodologies and transduction with DNRII, CB-derived DNRII-transduced NK cells expanded to clinically relevant numbers and retained both their killing ability and their secretion of interferon-γ upon activation. More important, these cells maintained both perforin expression and NKG2D/DNMA1 expression in the presence of TGF-ß allowing for recognition and killing of glioblastoma tumor cells. Hence, NK cells expressing a DNRII should have a functional advantage over unmodified NK cells in the presence of TGF-ß-secreting tumors and may be an important therapeutic approach for patients with cancer.

Prussian blue nanoparticle-based photothermal therapy combined with checkpoint inhibition for photothermal immunotherapy of neuroblastoma.

We describe "photothermal immunotherapy," which combines Prussian blue nanoparticle (PBNP)-based photothermal therapy (PTT) with anti-CTLA-4 checkpoint inhibition for treating neuroblastoma, a common, hard-to-treat pediatric cancer. PBNPs exhibit pH-dependent stability, which makes them suitable for intratumorally-administered PTT. PBNP-based PTT is able to lower tumor burden and prime an immune response, specifically an increased infiltration of lymphocytes and T cells to the tumor area, which is complemented by the antitumor effects of anti-CTLA-4 immunotherapy, providing a more durable treatment against neuroblastoma in an animal model. We observe 55.5% survival in photothermal immunotherapy-treated mice at 100days compared to 12.5%, 0%, 0%, and 0% survival in mice receiving: anti-CTLA-4 alone, PBNPs alone, PTT alone, and no treatment, respectively. Additionally, long-term surviving, photothermal immunotherapy-treated mice exhibit protection against neuroblastoma rechallenge, suggesting the development of immunity against these tumors. Our findings suggest the potential of photothermal immunotherapy in improving treatments for neuroblastoma.

Tungsten-doped TiO2/reduced Graphene Oxide nano-composite photocatalyst for degradation of phenol: A system to reduce surface and bulk electron-hole recombination.

Recombination of photogenerated charges is the main factor affecting the photocatalytic activity of TiO2. Here, we report a combined strategy of suppressing both the bulk as well as the surface recombination processes by doping TiO2 with tungsten and forming a nanocomposite with reduced graphene oxide (rGO), respectively. Sol-gel method was used to dope and optimize the concentration of W in TiO2 powder. UV-Vis, XPS, PL and time resolved PL spectra along with DFT calculations indicate that W6+ in TiO2 lattice creates an impurity level just below the conduction band of TiO2 to act as a trapping site of electrons, which causes to improve the lifetime of the photo-generated charges. Maximum reduction in the PL intensity and the improvement in charge carrier lifetime was observed for TiO2 doped with 1 at.% W (1W-TiO2), which also displayed the highest photo-activity for the degradation of p-nitro phenol pollutant in water. Tuning of rGO/TiO2 ratio (weight) disclosed that the highest activity can be achieved with the composite formed by taking equal amounts of TiO2 and rGO (1:1), in which the strong interaction between TiO2 and rGO causes an effective charge transfer via bonds formed near the interface as indicated by XPS. Both these optimized concentrations were utilized to form the composite rGO/1W-TiO2, which showed the highest activity in photo-degradation of p-nitro phenol (87%) as compared to rGO/TiO2 (42%), 1W-TiO2 (62%) and pure TiO2 (29%) in 180 min. XPS and PL results revealed that in the present nanocomposite, tungsten species traps the excited electron to reduce the interband recombination in the bulk, while the interaction between TiO2 and rGO creates a channel for fast transfer of excited electrons towards the latter before being recombined on the surface defect sites.

Improving efficacy of cancer immunotherapy by genetic modification of natural killer cells.

Natural killer (NK) cells are members of the innate immune system that recognize target cells via activating and inhibitory signals received through cell receptors. Derived from the lymphoid lineage, NK cells are able to produce cytokines and exert a cytotoxic effect on viral infected and malignant cells. It is their unique ability to lyse target cells rapidly and without prior education that renders NK cells a promising effector cell for adoptive cell therapy. However, both viruses and tumors employ evasion strategies to avoid attack by NK cells, which represent biological challenges that need to be harnessed to fully exploit the cytolytic potential of NK cells. Using genetic modification, the function of NK cells can be enhanced to improve their homing, cytolytic activity, in vivo persistence and safety. Examples include gene modification to express chemokine, high-affinity Fc receptor and chimeric antigen receptors, suicide genes and the forced expression of cytokines such as interleukin (IL)-2 and IL-15. Preclinical studies have clearly demonstrated that such approaches are effective in improving NK-cell function, homing and safety. In this review, we summarize the recent advances in the genetic manipulations of NK cells and their application for cellular immunotherapeutic strategies.

Biofunctionalized gadolinium-containing prussian blue nanoparticles as multimodal molecular imaging agents.

Molecular imaging agents enable the visualization of phenomena with cellular and subcellular level resolutions and therefore have enormous potential in improving disease diagnosis and therapy assessment. In this article, we describe the synthesis, characterization, and demonstration of core-shell, biofunctionalized, gadolinium-containing Prussian blue nanoparticles as multimodal molecular imaging agents. Our multimodal nanoparticles combine the advantages of MRI and fluorescence. The core of our nanoparticles consists of a Prussian blue lattice with gadolinium ions located within the lattice interstices that confer high relaxivity to the nanoparticles providing MRI contrast. The relaxivities of our nanoparticles are nearly nine times those observed for the clinically used Magnevist. The nanoparticle MRI core is biofunctionalized with a layer of fluorescently labeled avidin that enables fluorescence imaging. Biotinylated antibodies are attached to the surface avidin and confer molecular specificity to the nanoparticles by targeting cell-specific biomarkers. We demonstrate our nanoparticles as multimodal molecular imaging agents in an in vitro model consisting of a mixture of eosinophilic cells and squamous epithelial cells. Our nanoparticles specifically detect eosinophilic cells and not squamous epithelial cells, via both fluorescence imaging and MRI in vitro. These results suggest the potential of our biofunctionalized Prussian blue nanoparticles as multimodal molecular imaging agents in vivo.

Bifunctional Amorphous Transition-Metal Phospho-Boride Electrocatalysts for Selective Alkaline Seawater Splitting at a Current Density of 2A cm-2.

Hydrogen production by direct seawater electrolysis is an alternative technology to conventional freshwater electrolysis, mainly owing to the vast abundance of seawater reserves on earth. However, the lack of robust, active, and selective electrocatalysts that can withstand the harsh and corrosive saline conditions of seawater greatly hinders its industrial viability. Herein, a series of amorphous transition-metal phospho-borides, namely Co-P-B, Ni-P-B, and Fe-P-B are prepared by simple chemical reduction method and screened for overall alkaline seawater electrolysis. Co-P-B is found to be the best of the lot, requiring low overpotentials of ≈270 mV for hydrogen evolution reaction (HER), ≈410 mV for oxygen evolution reaction (OER), and an overall voltage of 2.50 V to reach a current density of 2 A cm-2 in highly alkaline natural seawater. Furthermore, the optimized electrocatalyst shows formidable stability after 10,000 cycles and 30 h of chronoamperometric measurements in alkaline natural seawater without any chlorine evolution, even at higher current densities. A detailed understanding of not only HER and OER but also chlorine evolution reaction (ClER) on the Co-P-B surface is obtained by computational analysis, which also sheds light on the selectivity and stability of the catalyst at high current densities.

Photothermal Prussian blue nanoparticles generate potent multi-targeted tumor-specific T cells as an adoptive cell therapy.

Prussian blue nanoparticle-based photothermal therapy (PBNP-PTT) is an effective tumor treatment capable of eliciting an antitumor immune response. Motivated by the ability of PBNP-PTT to potentiate endogenous immune responses, we recently demonstrated that PBNP-PTT could be used ex vivo to generate tumor-specific T cells against glioblastoma (GBM) cell lines as an adoptive T cell therapy (ATCT). In this study, we further developed this promising T cell development platform. First, we assessed the phenotype and function of T cells generated using PBNP-PTT. We observed that PBNP-PTT facilitated CD8+ T cell expansion from healthy donor PBMCs that secreted IFNγ and TNFα and upregulated CD107a in response to engagement with target U87 cells, suggesting specific antitumor T cell activation and degranulation. Further, CD8+ effector and effector memory T cell populations significantly expanded after co-culture with U87 cells, consistent with tumor-specific effector responses. In orthotopically implanted U87 GBM tumors in vivo, PBNP-PTT-derived T cells effectively reduced U87 tumor growth and generated long-term survival in >80% of tumor-bearing mice by Day 100, compared to 0% of mice treated with PBS, non-specific T cells, or T cells expanded from lysed U87 cells, demonstrating an enhanced antitumor efficacy of this ATCT platform. Finally, we tested the generalizability of our approach by generating T cells targeting medulloblastoma (D556), breast cancer (MDA-MB-231), neuroblastoma (SH-SY5Y), and acute monocytic leukemia (THP-1) cell lines. The resulting T cells secreted IFNγ and exerted increased tumor-specific cytolytic function relative to controls, demonstrating the versatility of PBNP-PTT in generating tumor-specific T cells for ATCT.

Encapsulated fusion protein confers "sense and respond" activity to chitosan-alginate capsules to manipulate bacterial quorum sensing.

We demonstrate that "nanofactory"-loaded biopolymer capsules placed in the midst of a bacterial population can direct bacterial communication. Quorum sensing (QS) is a process by which bacteria communicate through small-molecules, such as autoinducer-2 (AI-2), leading to collective behaviors such as virulence and biofilm formation. In our approach, a "nanofactory" construct is created, which comprises an antibody complexed with a fusion protein that produces AI-2. These nanofactories are entrapped within capsules formed by electrostatic complexation of cationic (chitosan) and anionic (sodium alginate) biopolymers. The chitosan capsule shell is crosslinked by tripolyphosphate (TPP) to confer structural integrity. The capsule shell is impermeable to the encapsulated nanofactories, but freely permeable to small molecules. In turn, the capsules are able to take in substrates from the external medium via diffusion, and convert these via the nanofactories into AI-2, which then diffuses out. The exported AI-2 is shown to stimulate QS responses in vicinal Escherichia coli. Directing bacterial population behavior has potential applications in next-generation antimicrobial therapy and pathogen detection. We also envision such capsules to be akin to artificial "cells" that can participate in native biological signaling and communicate in real-time with the human microbiome. Through such interaction capabilities, these "cells" may sense the health of the microbiome, and direct its function in a desired, host-friendly manner.

Nanodepots Encapsulating a Latency Reversing Agent and Broadly Neutralizing Antibody Enhance Natural Killer Cell Cytotoxicity Against an in vitro Model of Latent HIV.

Purpose: Current antiretroviral therapies (ART) for human immunodeficiency virus (HIV) are not curative, as the virus persists in latent reservoirs, requiring lifelong adherence to ART and increasing the risk of co-morbidities. "Shock and kill" approaches to reactivate HIV from latent reservoirs followed by administration of anti-HIV drugs represent a promising strategy for eradicating latent HIV. To achieve effective shock and kill, we describe a strategy to eradicate the HIV reservoir that combines latency reversing agents (LRAs), broadly neutralizing antibodies (bnAbs), and natural killer (NK) cells. This strategy utilizes a polymer nanodepot (ND) that co-encapsulates the LRA and bnAb to reactivate latent infection and elicit enhanced cytotoxicity from co-administered NK cells. Methods: Poly(lactic-co-glycolic acid) (PLGA) NDs were synthesized using the nanoprecipitation method to co-encapsulate an LRA (TNF-α) and a bnAb (3BNC117) (TNF-α-3BNC117-NDs). ACH-2 cells were used as a cellular model of latent HIV infection. An NK92 subline, genetically modified to constitutively express the Fc receptor CD16, was administered to ACH-2 cells in combination with TNF-α-3BNC117-NDs. ACH-2 cell death and extracellular p24 were measured via flow cytometry and ELISA, respectively. Results: Stable PLGA NDs co-encapsulated TNF-α and 3BNC117 with high efficiencies and released these agents in physiological conditions. NK92 phenotype remained similar in the presence of TNF-α-3BNC117-NDs. TNF-α released from NDs efficiently reactivated HIV in ACH-2 cells, as measured by a 3.0-fold increase in the frequency of intracellular p24 positive cells. Released 3BNC117 neutralized and bound reactivated virus, targeting 57.5% of total ACH-2 cells. Critically, TNF-α-3BNC117-NDs significantly enhanced NK92 cell-mediated killing of ACH-2 cells (1.9-fold) and reduced extracellular levels of p24 to baseline. Conclusion: These findings suggest the therapeutic potential of our novel ND-based tripartite strategy to reactivate HIV from latently infected cells, generate an HIV-specific site for bnAb binding, and enhance the killing of reactivated HIV-infected target cells by NK92 cells.

The Thermal Dose of Photothermal Therapy Generates Differential Immunogenicity in Human Neuroblastoma Cells.

Photothermal therapy (PTT) is an effective method for tumor eradication and has been successfully combined with immunotherapy. However, besides its cytotoxic effects, little is known about the effect of the PTT thermal dose on the immunogenicity of treated tumor cells. Therefore, we administered a range of thermal doses using Prussian blue nanoparticle-based photothermal therapy (PBNP-PTT) and assessed their effects on tumor cell death and concomitant immunogenicity correlates in two human neuroblastoma cell lines: SH-SY5Y (MYCN-non-amplified) and LAN-1 (MYCN-amplified). PBNP-PTT generated thermal dose-dependent tumor cell killing and immunogenic cell death (ICD) in both tumor lines in vitro. However, the effect of the thermal dose on ICD and the expression of costimulatory molecules, immune checkpoint molecules, major histocompatibility complexes, an NK cell-activating ligand, and a neuroblastoma-associated antigen were significantly more pronounced in SH-SY5Y cells compared with LAN-1 cells, consistent with the high-risk phenotype of LAN-1 cells. In functional co-culture studies in vitro, T cells exhibited significantly higher cytotoxicity toward SH-SY5Y cells relative to LAN-1 cells at equivalent thermal doses. This preliminary report suggests the importance of moving past the traditional focus of using PTT solely for tumor eradication to one that considers the immunogenic effects of PTT thermal dose to facilitate its success in cancer immunotherapy.

Anti-Fn14-Conjugated Prussian Blue Nanoparticles as a Targeted Photothermal Therapy Agent for Glioblastoma.

Prussian blue nanoparticles (PBNPs) are effective photothermal therapy (PTT) agents: they absorb near-infrared radiation and reemit it as heat via phonon-phonon relaxations that, in the presence of tumors, can induce thermal and immunogenic cell death. However, in the context of central nervous system (CNS) tumors, the off-target effects of PTT have the potential to result in injury to healthy CNS tissue. Motivated by this need for targeted PTT agents for CNS tumors, we present a PBNP formulation that targets fibroblast growth factor-inducible 14 (Fn14)-expressing glioblastoma cell lines. We conjugated an antibody targeting Fn14, a receptor abundantly expressed on many glioblastomas but near absent on healthy CNS tissue, to PBNPs (aFn14-PBNPs). We measured the attachment efficiency of aFn14 onto PBNPs, the size and stability of aFn14-PBNPs, and the ability of aFn14-PBNPs to induce thermal and immunogenic cell death and target and treat glioblastoma tumor cells in vitro. aFn14 remained stably conjugated to the PBNPs for at least 21 days. Further, PTT with aFn14-PBNPs induced thermal and immunogenic cell death in glioblastoma tumor cells. However, in a targeted treatment assay, PTT was only effective in killing glioblastoma tumor cells when using aFn14-PBNPs, not when using PBNPs alone. Our methodology is novel in its targeting moiety, tumor application, and combination with PTT. To the best of our knowledge, PBNPs have not been investigated as a targeted PTT agent in glioblastoma via conjugation to aFn14. Our results demonstrate a novel and effective method for delivering targeted PTT to aFn14-expressing tumor cells via aFn14 conjugation to PBNPs.

PolyIC-coated Prussian blue nanoparticles as a dual-mode HIV latency reversing agent.

Aim: To investigate Prussian blue nanoparticles (PBNPs) coated with the synthetic analog of dsRNA polyinosinic-polycytidylic acid (polyIC) for their ability to function as HIV latency reversing agents. Methods: A layer-by-layer method was used to synthesize polyIC-coated PBNPs (polyIC-PBNPs). PolyIC-PBNPs were stable and monodisperse, maintained the native absorbance properties of both polyIC and PBNPs and were obtained with high nanoparticle collection yield and polyIC attachment efficiencies. Results: PolyIC-PBNPs were more effective in reactivating latent HIV than free polyIC in a cell model of HIV latency. Furthermore, polyIC-PBNPs were more effective in promoting immune activation than free polyIC in CD4 and CD8 T cells. Conclusion: PBNPs function as efficient carriers of nucleic acids to directly reverse HIV latency and enhance immune activation.

HIV is a virus that attacks and weakens the immune system. If left untreated, HIV infection leads to AIDS. To combat this, administration of antiretroviral therapy allows HIV to be controlled, and an infected individual may live a normal life. However, there is no cure for HIV because the virus persists within hidden reservoirs of latently infected cells that remain undetected by the immune system. A cure strategy currently under investigation in the field utilizes a latency reversing agent (LRA) to reactivate latent HIV with the goal of promoting a response from the immune system. To achieve this goal, this study used a nanoparticle-based method to administer LRAs. More specifically, the authors synthesized Prussian blue nanoparticles (PBNPs) coated with the LRA polyinosinic-polycytidylic acid (polyIC), a synthetic analog of dsRNA. This study demonstrates that when administered in the form of nanoparticles, polyIC-coated PBNPs generate both enhanced reactivation of HIV and immune activation when compared with free polyIC. These results indicate a promising potential for using PBNPs to deliver LRAs such as polyIC to enhance current and future HIV cure strategies.

Interstitial Photothermal Therapy Generates Durable Treatment Responses in Neuroblastoma.

Photothermal therapy (PTT) represents a promising modality for tumor control typically using infrared light-responsive nanoparticles illuminated by a wavelength-matched external laser. However, due to the constraints of light penetration, PTT is generally restricted to superficially accessible tumors. With the goal of extending the benefits of PTT to all tumor settings, interstitial PTT (I-PTT) is evaluated by the photothermal activation of intratumorally administered Prussian blue nanoparticles with a laser fiber positioned interstitially within the tumor. This interstitial fiber, which is fitted with a terminal diffuser, distributes light within the tumor microenvironment from the "inside-out" as compared to from the "outside-in" traditionally observed during superficially administered PTT (S-PTT). I-PTT improves the heating efficiency and heat distribution within a target treatment area compared to S-PTT. Additionally, I-PTT generates increased cytotoxicity and thermal damage at equivalent thermal doses, and elicits immunogenic cell death at lower thermal doses in targeted neuroblastoma tumor cells compared to S-PTT. In vivo, I-PTT induces significantly higher long-term tumor regression, lower rates of tumor recurrence, and improved long-term survival in multiple syngeneic murine models of neuroblastoma. This study highlights the significantly enhanced therapeutic benefit of I-PTT compared to traditional S-PTT as a promising treatment modality for solid tumors.

CD137 agonist potentiates the abscopal efficacy of nanoparticle-based photothermal therapy for melanoma.

Despite the promise of immunotherapy such as the immune checkpoint inhibitors (ICIs) anti-PD-1 and anti-CTLA-4 for advanced melanoma, only 26%-52% of patients respond, and many experience grade III/IV immune-related adverse events. Motivated by the need for an effective therapy for patients non-responsive to clinically approved ICIs, we have developed a novel nanoimmunotherapy that combines locally administered Prussian blue nanoparticle-based photothermal therapy (PBNP-PTT) with systemically administered agonistic anti-CD137 monoclonal antibody therapy (aCD137). PBNP-PTT was administered at various thermal doses to melanoma cells in vitro, and was combined with aCD137 in vivo to test treatment effects on melanoma tumor progression, animal survival, immunological protection against tumor rechallenge, and hepatotoxicity. When administered at a melanoma-specific thermal dose, PBNP-PTT elicits immunogenic cell death (ICD) in melanoma cells and upregulates markers associated with antigen presentation and immune cell co-stimulation in vitro. Consequently, PBNP-PTT eliminates primary melanoma tumors in vivo, yielding long-term tumor-free survival. However, the antitumor immune effects generated by PBNP-PTT cannot eliminate secondary tumors, despite significantly slowing their growth. The addition of aCD137 enables significant abscopal efficacy and improvement of survival, functioning through activated dendritic cells and tumor-infiltrating CD8+ T cells, and generates CD4+ and CD8+ T cell memory that manifests in the rejection of tumor rechallenge, with no long-term hepatotoxicity. This study describes for the first time a novel and effective nanoimmunotherapy combination of PBNP-PTT with aCD137 mAb therapy for melanoma.

Self-folding micropatterned polymeric containers.

We demonstrate self-folding of precisely patterned, optically transparent, all-polymeric containers and describe their utility in mammalian cell and microorganism encapsulation and culture. The polyhedral containers, with SU-8 faces and biodegradable polycaprolactone (PCL) hinges, spontaneously assembled on heating. Self-folding was driven by a minimization of surface area of the liquefying PCL hinges within lithographically patterned two-dimensional (2D) templates. The strategy allowed for the fabrication of containers with variable polyhedral shapes, sizes and precisely defined porosities in all three dimensions. We provide proof-of-concept for the use of these polymeric containers as encapsulants for beads, chemicals, mammalian cells and bacteria. We also compare accelerated hinge degradation rates in alkaline solutions of varying pH. These optically transparent containers resemble three-dimensional (3D) micro-Petri dishes and can be utilized to sustain, monitor and deliver living biological components.