Chlorin-Based Nanoscale Metal-Organic Framework Systemically Rejects Colorectal Cancers via Synergistic Photodynamic Therapy and Checkpoint Blockade Immunotherapy

Tumor Microenvironment Targeting Nano-Bio Emulsion for Synergistic Combinational X-Ray PDT with Oncolytic Bacteria Therapy

Various cancer therapies have been developed, but tumor recurrence with incomplete tumor killing and remaining tumor cells/tissues is frequent in monotherapies. Herein, a nano-bio therapeutic emulsion formulated with multifunctional nanoscintillators and anaerobic Clostridium novyi-NT spores for synergistic image-guided combinational cancer therapy is reported. MRI visible nanoscintillators (NSs) are synthesized with a NaGdF4 :Tb,Ce@NaGdF4 core/shell structure for an image-guided X-ray photodynamic therapy (PDT) of the normoxic peripheral tumor. An anaerobic oncolytic bacterium (C. novyi-NT) therapy is combined to treat the hypoxic central tumor tissues. Photosensitizer-coated NSs (PS-NSs) and C. novyi-NT spores are emulsified with clinically available ethiodized oil (Lipiodol) to be the nano-bio therapeutic emulsion and injected into the tumor with computed tomography image guidance. The distribution of nano-bio therapeutic emulsion, including PS-NSs and anaerobic C. novyi-NT spores in the tumor site, is confirmed by both X-ray and T1 -weighted magnetic resonance imaging. Following the image-guided X-ray PDT and anaerobic C. novyi- NT combination treatment, apoptotic cell death in cancer tissues, including both peripheral and central tumor regions, is significantly higher than in the control groups. This combination therapy approach using a nano-bio therapeutic emulsion is expected to overcome the limitations of conventional cancer therapy, resulting in increased cancer-therapeutic efficacy.

A tumor acidity activatable and Ca2+-assisted immuno-nanoagent enhances breast cancer therapy and suppresses cancer recurrence

Breast cancer recurrence is the greatest contributor to patient death. As the immune system has a long-term immune memory effect, immunotherapy has great potential for preventing cancer recurrence. However, cancer immunotherapy is often limited due to T cell activation being blocked by insufficient tumor immunogenicity and the complex immunosuppressive tumor microenvironment. Here we show a tumor acidity activatable and Ca2+-assisted immuno-nanoagent to synergistically promote T cell activation and enhance cancer immunotherapy. When the immuno-nanoagent reaches the acidic tumor microenvironment, the CaCO3 matrix disintegrates to release immune stimulants (CpG ODNs and IDOi) and Ca2+. CpG ODNs are responsible for triggering dendritic cell maturation to increase the immunogenicity for activation of T cells. And IDOi can inhibit the oxidative catabolism of tryptophan to kynurenine for preventing T-cell anergy and apoptosis. Due to the complexity of the immunosuppressive microenvironment, it is difficult to restore T cell activation by inhibiting only one pathway. Fortunately, the released Ca2+ can promote the activation and proliferation of T cells with the support of the immune stimulants. In vivo experiments demonstrate that our Ca2+-assisted immuno-nanoagent can significantly suppress tumor progression and protect mice from tumor rechallenge due to the long-term memory effect. This immunotherapeutic strategy may provide more possibilities for clinical applications such as treating cancer and preventing relapse.

Nanoscale Metal-Organic Frameworks Generate Reactive Oxygen Species for Cancer Therapy

In the past 15 years, enormous progress has been made in cancer nanotechnology, and a several nanoparticles have entered clinical testing for cancer treatment. Among these nanoparticles are nanoscale metal-organic frameworks (nMOFs), a class of organic-inorganic hybrid nanomaterials constructed from metal binding sites and bridging ligands, which have attracted significant attention for their ability to integrate porosity, crystallinity, compositional and structural tunability, multifunctionality, and biocompatibility into a singular nanomaterial for cancer therapies. This Outlook article summarizes the progress on the design of nMOFs as nanosensitizers for photodynamic therapy (PDT), radiotherapy (RT), radiotherapy-radiodynamic therapy (RT-RDT), and chemodynamic therapy (CDT) via nMOF-mediated reactive oxygen species (ROS) generated under external energy stimuli or in the presence of endogenous chemical triggers. Inflammatory responses induced by nMOF-mediated ROS generation activate tumor microenvironments to potentiate cancer immunotherapy, extending the local treatment effects of nMOF-based ROS therapy to distant tumors via abscopal effects. Future research directions in nMOF-mediated ROS therapies and the prospect of clinical applications of nMOFs as cancer therapeutics are also discussed.

Micron-Sized Ultrathin Metal-Organic Framework Sheet

The two-dimensional thin metal-organic frameworks (MOF) sheet has emerged as a promising hybrid material for applications in catalysis and optoelectronic devices. However, the small size and large thickness of an MOF sheet still pose barriers toward its potential applications. Herein, a micron-sized ultrathin MOF sheet is synthesized with the assistance of benzoic acid. Benzoic acid promoted the coordination of the porphyrin center with copper ions, reduced H-stacking and J-aggregation between the layers, and induced anisotropic growth of the MOF sheet. The results reveal the growth mechanism and provide a viable method for the synthesis of ultrathin MOF sheet. The as-prepared micron-sized ultrathin MOF sheet has good dispersion and high stability, which can ensure the long-term application properties of this material. The ultrathin thickness in combination with its micron size can make MOF as useful as graphene in practical applications. The synthesis of a micron-sized ultrathin MOF sheet similar to the thickness of graphene can pave the way for effective applications of two-dimensional MOF materials.

Rationally Designed Polymer Conjugate for Tumor-Specific Amplification of Oxidative Stress and Boosting Antitumor Immunity

The crosstalk between tumor and stroma cells is a central scenario in the tumor microenvironment (TME). While the predominant effect of tumor cells on immune cells is establishing an immunosuppressive context, tumor cell death at certain conditions will boost antitumor immunity. Herein, we report a rationally designed tumor specific enhanced oxidative stress polymer conjugate (TSEOP) for boosting antitumor immunity. The TSEOP is prepared by Passerini reaction between cinnamaldehyde (CA), 4-formylbenzeneboronic acid pinacol ester, and 5-isocyanopent-1-yne, followed by azide-alkyne click reaction with poly(l-glutamic acid)-graft-poly(ethylene glycol) monomethyl ether (PLG-g-mPEG). Under tumor stimuli condition, CA and quinone methide (QM) are quickly generated, which cooperatively induce strong oxidative stress, immunogenic tumor cell death (ICD), and activation of antigen presenting cells. In vivo studies show that the TSEOP treatment boosts tumor-specific antitumor immunity and eradicates both murine colorectal and breast tumors. This study should be inspirational for designing polymers as immunotherapeutics in cancer therapy.

Recent Progress of Potentiating Immune Checkpoint Blockade with External Stimuli-an Industry Perspective

The past decade has seen the materialization of immune checkpoint blockade as an emerging approach to cancer treatment. However, the overall response and patient survival are still modest. Various efforts to study the "cancer immunogram" have highlighted complex biology that necessitates a multipronged approach. This includes increasing the antigenicity of the tumor, strengthening the immune infiltration in the tumor microenvironment, removing the immunosuppressive mechanisms, and reducing immune cell exhaustion. The coordination of these approaches, as well as the ability to enhance them through delivery, is evaluated. Due to their success in multiple preclinical models, external-stimuli-responsive nanoparticles have received tremendous attention. Several studies report success in distantly located tumor regression, metastases, and reoccurrence in preclinical mouse models. However, clinical translation in this space remains low. Herein, the recent advancement in external-stimuli-responsive nanoconstruct-synergized immune checkpoint blockade is summarized, offering an industry perspective on the limitations of current academic innovations and discussing challenges in translation from a technical, manufacturing, and regulatory perspective. These limitations and challenges will need to be addressed to establish external-stimuli-based therapeutic strategies for patients.

A promising anticancer drug: a photosensitizer based on the porphyrin skeleton

Photodynamic therapy (PDT) is a minimally invasive combination of treatments that treat tumors and other diseases by using photosensitizers, light and oxygen to produce cytotoxic reactive oxygen species (ROS) inducing tumor cell apoptosis. Photosensitizers are the key part of PDT for clinical application and experimental research, and most of them are porphyrin compounds at present. Due to their unique affinity for tumor tissues, porphyrins are not only excellent photosensitizers, but also good carriers to transport other active drugs into tumor tissues, which can exert synergistic anticancer effects of PDT and chemotherapy. This article reviews the clinical development of porphyrin photosensitizers and the research status of porphyrin containing bioactive groups. Finally, future perspectives and the current challenges of photosensitizers based on the porphyrin skeleton are discussed.

Materials for Immunotherapy

Breakthroughs in materials engineering have accelerated the progress of immunotherapy in preclinical studies. The interplay of chemistry and materials has resulted in improved loading, targeting, and release of immunomodulatory agents. An overview of the materials that are used to enable or improve the success of immunotherapies in preclinical studies is presented, from immunosuppressive to proinflammatory strategies, with particular emphasis on technologies poised for clinical translation. The materials are organized based on their characteristic length scale, whereby the enabling feature of each technology is organized by the structure of that material. For example, the mechanisms by which i) nanoscale materials can improve targeting and infiltration of immunomodulatory payloads into tissues and cells, ii) microscale materials can facilitate cell-mediated transport and serve as artificial antigen-presenting cells, and iii) macroscale materials can form the basis of artificial microenvironments to promote cell infiltration and reprogramming are discussed. As a step toward establishing a set of design rules for future immunotherapies, materials that intrinsically activate or suppress the immune system are reviewed. Finally, a brief outlook on the trajectory of these systems and how they may be improved to address unsolved challenges in cancer, infectious diseases, and autoimmunity is presented.

Site-specific MOF-based immunotherapeutic nanoplatforms via synergistic tumor cells-targeted treatment and dendritic cells-targeted immunomodulation

An efficient antitumor immune response relies on multiple cells-based process including tumor cells-targeted immunogenicity increment, dendritic cells (DCs)-targeted vaccine delivery and T cells-mediated tumor elimination. Only limited immune efficacy could be achieved by strengthening the function of single type of cells. Therefore, building an effective immunotherapeutic nanoplatform by simultaneously modulating the functions of multiple cells involved in immune process is urgently demanded. However, it is challenging to modulate multiple cells since the on-demand delivery of diverse agents to different cells is restricted by inherent different target sites. Herein, as a proof of concept, dual tailor-made metal organic framework (MOF) nanoparticles based on zeolitic imidazolate framework-8 (ZIF-8) are designed to comprehensively enhance the immunotherapy via the spatiotemporal cooperation of various therapeutic agents including photothermal agent IR820, adjuvant imiquimod (R837) and immunomodulator 1-methyl-d-tryptophan (1 MT). On one hand, IR820@ZIF-8 is modified with hyaluronic acid for realizing tumor-targeted photothermal therapy, accompanied with the release of tumor antigens. On the other hand, (R837+1 MT)@ZIF-8 is modified with mannan for achieving DCs-targeted immune amplification. The synergistic tumor cells-targeted treatment and DCs-targeted immunomodulation can efficiently overcome two major obstacles in immunotherapy: inadequate activation of immune response and immune evasion, offering powerful platform against invasive malignancy and rechallenged tumors.

Structurally Characterized BODIPY-Appended Oxidovanadium(IV) β-Diketonates for Mitochondria-Targeted Photocytotoxicity

Mixed-ligand oxidovanadium(IV) β-diketonates having NNN-donor dipicolylamine-conjugated to boron-dipyrromethene (BODIPY in L₁) and diiodo-BODIPY (in L₂) moieties, namely, [VO(L₁)(acac)]Cl (1), [VO(L₂)(acac)]Cl (2), and [VO(L₁)(dbm)]Cl (3), where acac and dbm are monoanionic O,O-donor acetylacetone and 1,3-diphenyl-1,3-propanedione, were prepared, characterized, and tested for their photoinduced anticancer activity in visible light. Complexes 1 and 2 were structurally characterized as their PF₆ ^- salts (1a and 2a) by X-ray crystallography. They showed V^IVN₃O₃ six-coordinate geometry with dipicolylamine base as the facial ligand. The non-iodinated BODIPY complexes displayed absorption maxima at ∼501 nm, while it is ∼535 nm for the di-iodinated 2 in 10% DMSO-PBS buffer medium (pH = 7.2). Complexes 1 and 3 being green emissive (λ_em, ∼512 nm; λ_ex, 470 nm; Φ_F, ∼0.10) in 10% aqueous DMSO were used for cellular imaging studies. Complex 3 localized primarily in the mitochondria of the cervical HeLa cells with a co-localization coefficient value of 0.7. The non-emissive diiodo-BODIPY complex 2 showed generation of singlet oxygen (Φ_Δ ≈ 0.47) on light activation. Annexin-V assay showed singlet oxygen-mediated cellular apoptosis, making this complex a targeted PDT agent.

Tumor-targeted nanoplatform for in situ oxygenation-boosted immunogenic phototherapy of colorectal cancer

Advanced colorectal cancer has a high mortality rate since conventional treatments have limited therapeutic effects and poor prognosis with high risks of metastasis and recurrence. Photodynamic therapy (PDT) is a promising treatment modality for the eradication of colorectal cancer, but its curative efficacy is severely affected by tumor hypoxia. Herein, we developed a core-shell gold nanocage coated with manganese dioxide and hyaluronic acid (AMH) for targeted delivery to colorectal tumors and oxygenation-boosted immunogenic phototherapy in situ. The AMH nanoparticles can generate abundant oxygen from mild acidic/H₂O₂ medium, which can further enhance the PDT efficacy of AMH itself under near infrared (NIR) irradiation. Meanwhile, AMH-based PDT induced immunogenic cell death (ICD) of tumor cells with damage-associated molecular patterns (DAMPs) release and facilitated the dendritic cells (DCs) maturation to further potentiate the systematic antitumor immunity against advanced tumors. In vivo experiment results exhibited that AMH nanoparticles not only had the ability of targeting tumor but also in situ produced sufficient oxygen to relieve the tumor hypoxia. Furthermore, AMH-mediated oxygen-boosted immunogenic PDT effectively inhibited the tumor growth and recurrence. Thus, this work provides a potent targeted delivery nanoplatform for enhanced immunogenic PDT against advanced cancers. STATEMENT OF SIGNIFICANCE: Local hypoxic tumor microenvironment not only greatly limits the photodynamic therapy (PDT) efficacy, but also has an association with tumor invasiveness and metastasis. This study provides an AMH nanoparticle for targeted delivery to colorectal tumors and oxygenation-boosted immunogenic PDT in situ. AMH nanoparticle exhibits a good tumor-targeted ability to in situ produce abundant oxygen to relieve the tumor hypoxia, and initiates the potent oxygen-boosted immunogenic PDT effect under NIR irradiation to effectively inhibit the growth and recurrence of colorectal tumor. This oxygen-boosted immunogenic PDT nanosystem can be a promising candidate for advanced tumor treatment.

A bi-adjuvant nanovaccine that potentiates immunogenicity of neoantigen for combination immunotherapy of colorectal cancer

Neoantigen vaccines have been enthusiastically pursued for personalized cancer immunotherapy while vast majority of neoantigens have no or low immunogenicity. Here, a bi-adjuvant neoantigen nanovaccine (banNV) that codelivered a peptide neoantigen (Adpgk) with two adjuvants [Toll-like receptor (TLR) 7/8 agonist R848 and TLR9 agonist CpG] was developed for potent cancer immunotherapy. Specifically, banNVs were prepared by a nanotemplated synthesis of concatemer CpG, nanocondensation with cationic polypeptides, and then physical loading with hydrophobic R848 and Adpgk. The immunogenicity of the neoantigen was profoundly potentiated by efficient codelivery of neoantigen and dual synergistic adjuvants, which is accompanied by reduced acute systemic toxicity. BanNVs sensitized immune checkpoint programmed death receptor 1 (PD-1) on T cells, therefore, a combination of banNVs with aPD-1 conspicuously induced the therapy response and led to complete regression of 70% neoantigen-specific tumors without recurrence. We conclude that banNVs are promising to optimize personalized therapeutic neoantigen vaccines for cancer immunotherapy.

Metal-Organic Frameworks for Photodynamic Therapy: Emerging Synergistic Cancer Therapy

Photodynamic therapy (PDT) conducted by photosensitizers producing cytotoxic reactive oxygen species (ROS) under light irradiation is widely used in cancer treatment. A great number of photoactive nanoscale metal-organic frameworks (NMOFs) have been prepared for PDT. With the development of biomedicine and nanotechnology, many synergistic cancer therapies have emerged. In this mini-review, an overview on the latest progress in the application of NMOFs in PDT is provided, with emphasis on the recent emergence of some synergistic therapies.

Inhibition of IDO leads to IL-6-dependent systemic inflammation in mice when combined with photodynamic therapy

It was previously reported that the activation of antitumor immune response by photodynamic therapy (PDT) is crucial for its therapeutic outcome. Excessive PDT-mediated inflammation is accompanied by immunosuppressive mechanisms that protect tissues from destruction. Thus, the final effect of PDT strongly depends on the balance between the activation of an adoptive arm of immune response and a range of activated immunosuppressive mechanisms. Here, with flow cytometry and functional tests, we evaluate the immunosuppressive activity of tumor-associated myeloid cells after PDT. We investigate the antitumor potential of PDT combined with indoleamine 2,3-dioxygenase 1 (IDO) inhibitor in the murine 4T1 and E0771 orthotopic breast cancer models. We found that the expression of IDO, elevated after PDT, affects the polarization of T regulatory cells and influences the innate immune response. Our results indicate that, depending on a therapeutic scheme, overcoming IDO-induced immunosuppressive mechanisms after PDT can be beneficial or can lead to a systemic toxic reaction. The inhibition of IDO, shortly after PDT, activates IL-6-dependent toxic reactions that can be diminished by the use of anti-IL-6 antibodies. Our results emphasize that deeper investigation of the physiological role of IDO, an attractive target for immunotherapies of cancer, is of great importance.

Development of a nanodrug-delivery system camouflaged by erythrocyte membranes for the chemo/phototherapy of cancer

Aim: Development of a new drug-delivery system using a compound derived from Pronephrium penangianum (J5) for the treatment of cervical cancer. Materials & methods: The delivery system was developed using Prussian blue nanoparticles, camouflaged by red blood cell membrane and with folic acid surface modifications. Results: Our results showed the successful development of a nanodrug-delivery system, which increases the half-life and immune evasion ability of the drug. The mechanism of this system was through suppressing B-cell lymphoma 2 and increasing B-cell lymphoma 2-associated X protein and the cleaved caspase level. An in vivo study also confirmed good antitumor activity without any side effects to normal tissue. Conclusion: This drug-delivery system provides a good alternative for the treatment of cervical cancer using J5.

Photothermal therapy-induced immunogenic cell death based on natural melanin nanoparticles against breast cancer

A photothermal and immune co-therapy strategy based on natural melanin nanoparticles was developed for treating primary and abscopal breast cancers.

Recent advances in porphyrin-based nanocomposites for effective targeted imaging and therapy

Porphyrins are organic compounds that continue to attract much theoretical interest, and have been called the "pigments of life". They have a wide role in photodynamic and sonodynamic therapy, along with uses in magnetic resonance, fluorescence and photoacoustic imaging. There is a vast range of porphyrins that have been isolated or designed, but few of them have real clinical applications. Due to the hydrophobic properties of porphyrins, and their tendency to aggregate by stacking of the planar molecules they are difficult to work with in aqueous media. Therefore encapsulating them in nanoparticles (NPs) or attachment to various delivery vehicles have been used to improve delivery characteristics. Porphyrins can be used in a composite designed material with properties that allow specific targeting, immune tolerance, extended tissue lifetime and improved hydrophilicity. Drug delivery, healing and repairing of damaged organs, and cancer theranostics are some of the medical uses of porphyrin-based nanocomposites covered in this review.

Engineering of Upconverted Metal-Organic Frameworks for Near-Infrared Light-Triggered Combinational Photodynamic/Chemo-/Immunotherapy against Hypoxic Tumors

Metal-organic frameworks (MOFs) have shown great potential as nanophotosensitizers (nPSs) for photodynamic therapy (PDT). The use of such MOFs in PDT, however, is limited by the shallow depth of tissue penetration of short-wavelength light and the oxygen-dependent mechanism that renders it inadequate for hypoxic tumors. Here, to combat such limitations, we rationally designed core-shell upconversion nanoparticle@porphyrinic MOFs (UCSs) for combinational therapy against hypoxic tumors. The UCSs were synthesized in high yield through the conditional surface engineering of UCNPs and subsequent seed-mediated growth strategy. The heterostructure allows efficient energy transfer from the UCNP core to the MOF shell, which enables the near-infrared (NIR) light-triggered production of cytotoxic reactive oxygen species. A hypoxia-activated prodrug tirapazamine (TPZ) was encapsulated in nanopores of the MOF shell of the heterostructures to yield the final construct TPZ/UCSs. We demonstrated that TPZ/UCSs represent a promising system for achieving improved cancer treatment in vitro and in vivo via the combination of NIR light-induced PDT and hypoxia-activated chemotherapy. Furthermore, the integration of the nanoplatform with antiprogrammed death-ligand 1 (α-PD-L1) treatment promotes the abscopal effect to completely inhibit the growth of untreated distant tumors by generating specific tumor infiltration of cytotoxic T cells. Collectively, this work highlights a robust nanoplatform for combining NIR light-triggered PDT and hypoxia-activated chemotherapy with immunotherapy to combat the current limitations of tumor treatment.

Investigation of the demetallation of 10-aryl substituted synthetic chlorins under acidic conditions

The acidic demetallation of a series of sparsely substituted Zn(II) chlorins is reported. The chlorins were functionalized in the 10-position with substituents ranging from strongly electron donating mesityl and p-methoxyphenyl to electron-withdrawing p-nitrophenyl and pentafluorophenyl groups. The demetallation kinetics were investigated using UV-Visible absorption spectroscopy. Demetallation was carried out by exposing the metallochlorins dissolved in CH₂Cl₂ to an excess of trifluoroacetic acid. Reasonable correlation was found between the Hammett constant of the 10-substituent and the rate constant of the loss of the metal ion. The largest differences were observed between the p-methoxyphenyl and p-nitrophenyl-substituted Zn(II) chlorins, undergoing loss of Zn(II) with pseudo first order rate constants of 0.0789 × 10^-3 and 3.70 × 10^-3 min^-1, respectively. Taken together, these data establish the dramatic influence even subtle changes can have in altering the electronic properties of chlorins, which in turn impacts metallochlorin function.

Biomimetic Platinum Nanozyme Immobilized on 2D Metal-Organic Frameworks for Mitochondrion-Targeting and Oxygen Self-Supply Photodynamic Therapy

Photodynamic therapy (PDT) as a noninvasive therapy mode has attracted considerable attention in the field of oncotherapy. However, the PDT efficacy is restricted either by the tumor hypoxia environment or the inherent properties of photosensitizers (PSs) including bad water solution, photobleaching, and easy aggregation. Herein, we designed and synthesized a new two-dimensional (2D) metal-organic framework, Sm-tetrakis(4-carboxyphenyl)porphyrin (TCPP) nanosheets, by assembling transition metal ions (Sm³⁺) and PSs (TCPP), on which the catalase (CAT)-mimicking platinum nanozymes were then in situ grown for sufficient oxygen supply during PDT. The prepared Sm-TCPP with nanoplate morphology (∼100 nm in diameter) and ultrathin thickness (<10 nm) showed significantly enhanced ¹O₂ generation capacity due to the improved physicochemical properties and the enhanced intersystem crossing from heavy Sm nodes. More importantly, the CAT-mimicking Pt nanozyme on the Sm-TCPP nanosheets could effectively convert over-expressed H₂O₂ in the tumor microenvironment into O₂ to relieve tumor hypoxia. Further, the triphenylphosphine (TPP) molecule was introduced to Sm-TCPP-Pt to develop a mitochondrion-targeting and O₂ self-supply PDT system. The in vitro and in vivo experimental results based on the MCF-7 breast cancer model revealed that Sm-TCPP-Pt/TPP could relieve tumor hypoxia and the generated reactive oxygen species nearby intracellular mitochondria significantly induced cell apoptosis. This study offers an engineering strategy to integrate 2D PS-based metal-organic frameworks and nanozymes into a nanoplatform to surmount the pitfalls of traditional PDT.

A Nanoscale Metal-Organic Framework to Mediate Photodynamic Therapy and Deliver CpG Oligodeoxynucleotides to Enhance Antigen Presentation and Cancer Immunotherapy

Checkpoint blockade immunotherapy (CBI) awakes a host innate immune system and reactivates cytotoxic T cells to elicit durable response in some cancer patients. Now, a cationic nanoscale metal-organic framework, W-TBP, is used to facilitate tumor antigen presentation by enabling immunogenic photodynamic therapy (PDT) and promoting the maturation of dendritic cells (DCs). Comprised of dinuclear WVI secondary building units and photosensitizing 5,10,15,20-tetra(p-benzoato)porphyrin (TBP) ligands, cationic W-TBP mediates PDT to release tumor associated antigens and delivers immunostimulatory CpG oligodeoxynucleotides to DCs. The enhanced antigen presentation synergizes with CBI to expand and reinvigorate cytotoxic T cells, leading to superb anticancer efficacy and robust abscopal effects with >97 % tumor regression in a bilateral breast cancer model.

Dual-functional conjugates improving cancer immunochemotherapy by inhibiting tubulin polymerization and indoleamine-2,3-dioxygenase

A series of novel conjugates comprising tublin and IDO inhibitors were designed, synthesized and evaluated for their antiproliferative activity. Among them, HI5, composed of combretastatin A-4 (CA-4) and (D)-1-methyltryptophan (D-MT) by a linker, exhibited the most potent antitumor activity, in particular with higher IC₅₀ value (0.07 μM) than CA-4 (0.21 μM) against HeLa cancer cell line. Mechanism studies indicated that HI5 can inhibit tubulin polymerization and cell migration, cause G2/M phase arrest, concurrent induce apoptosis via the mitochondrial dependent apoptosis pathway and cause reactive oxidative stress generation in HeLa cells. Furthermore, HI5 can inhibit IDO expression and decrease kynurenine production, leading to stimulating T cells activation and proliferation to enhance antitumor immunity in vitro. Interestingly, HI5 can effectively limit the tumor growth in the HeLa xenograft mice models without causing significant loss of body weight. Consequently, such a conjugation can be a potent and safe immunochemotherapeutic method for improving cancer therapy.

Emerging Prospects for Nanoparticle-Enabled Cancer Immunotherapy

One of the standards for cancer treatment is cancer immunotherapy which treats both primary and metastasized tumors. Although cancer immunotherapeutics show better outcomes as compared with conventional approaches of cancer treatment, the currently used cancer immunotherapeutics have limited application in delivering cancer antigens to immune cells. Conversely, in solid tumors, tumor microenvironment suppresses the immune system leading to the evasion of anticancer immunity. Some promising attempts have been made to overcome these drawbacks by using different approaches, for instance, the use of biomaterial-based nanoparticles. Accordingly, various studies involving the application of nanoparticles in cancer immunotherapy have been discussed in this review article. This review not only describes the modes of cancer immunotherapy to reveal the importance of nanoparticles in this modality but also narrates nanoparticle-mediated delivery of cancer antigens and therapeutic supplements. Moreover, the impact of nanoparticles on the immunosuppressive behavior of tumor environment has been discussed. The last part of this review deals with cancer immunotherapy using a combination of traditional interventional oncology approach and image-guided local immunotherapy against cancer. According to recent studies, cancer therapy can potentially be improved through nanoparticle-based immunotherapy. In addition, drawbacks associated with the currently used cancer immunotherapeutics can be fixed by using nanoparticles.

Post-synthesis strategy to integrate porphyrinic metal–organic frameworks with CuS NPs for synergistic enhanced photo-therapy

A multi-functional nanoplatform (PCN-CuS-FA-ICG) for combined photodynamic and photothermal therapy was presented, which demonstrated good inhibition of tumor growth.

Peroxynitrite (ONOO−) generation from the HA-TPP@NORM nanoparticles based on synergistic interactions between nitric oxide and photodynamic therapies for elevating anticancer efficiency

Due to biological safety and negligible toxicity, nitric oxide (NO) therapy has gained increasing interest in the field of cancer therapy during the past few years.

Metal–organic framework based antibiotic release and antimicrobial response: an overview

MOF and MOF based heterostructures for antibacterial applications.

Biomaterial-assisted photoimmunotherapy for cancer

The biomaterials have been well designed as photoabsorbing/sensitizing agents or effective carriers to enhance the photoimmunotherapeutic efficacy and evade their side effects.

Photodynamic Therapy Combined with Antihypoxic Signaling and CpG Adjuvant as an In Situ Tumor Vaccine Based on Metal-Organic Framework Nanoparticles to Boost Cancer Immunotherapy

Photodynamic therapy (PDT) usually aggravates tumor hypoxia, which promotes the survival and metastasis of residue cancer cells; furthermore, although PDT-induced immunogenic death of cancer cells can induce host antitumor responses, such responses are generally weak and not enough to eliminate the residue cancer cells. Here, metal-organic framework (MOF)-based nanoparticles to combine PDT, antihypoxic signaling, and CpG adjuvant as an in situ tumor vaccine to boost host anticancer responses after PDT are designed. The MOF-based nanoparticles are self-assembled from H2 TCPP and zirconium ions with hypoxia inducible factor (HIF) signaling inhibitor (ACF) and immunologic adjuvant (CpG) loading, and hyaluronic acid (HA) coating on the surface. The final nanoparticles (PCN-ACF-CpG@HA) can specifically target cancer cells overexpressing CD44 receptor though HA; the aggravated hypoxic survival signaling after PDT can be blocked by ACF to inhibit the HIF-1α induced survival and metastasis. With the help of CpG adjuvant, the tumor associated antigens generated from PDT-based cancer cell destruction can initiate strong antitumor immune responses to eliminate residue cancer cells. Taken together, a novel in situ immunostimulatory strategy is designed to synergistically enhance therapeutic effects of PDT by activating host antitumor immune-responses both in vitro and in vivo, which may have great potential for clinical translation in future.

A near-infrared light-controlled, ultrasensitive one-step photoelectrochemical detection of dual cell apoptosis indicators in living cancer cells

The proposed near-infrared (NIR) light-controlled, one-step photoelectrochemical (PEC) strategy could simultaneously detect cell apoptosis indicators, phosphatidylserine (Pho) and sodium potassium adenosine triphosphatase (Sat), on living cancer cells.

Emerging combination strategies with phototherapy in cancer nanomedicine

Based on the challenges in single-mode phototherapy, this review summarizes the significant research progress in combinatorial strategies with phototherapy.

Photodynamic diagnosis and photodynamic therapy of colorectal cancer in vitro and in vivo

This review highlights the various photo diagnostic and treatment methods utilized for CRC, over the last seven years.

Metal–organic frameworks: a future toolbox for biomedicine?

The present review focuses on the use of Metal–Organic Frameworks, (MOFs) highlighting the most recent developments in the biological field and as bio-sensors.

Recent Progress of Nanoscale Metal-Organic Frameworks in Cancer Theranostics and the Challenges of Their Clinical Application

The growing incidence of cancer raises an urgent need to develop effective diagnostic and therapeutic strategies. With the rapid development of nanomedicine, nanoscale metal-organic frameworks (NMOFs) presented promising potential in various biomedical applications in the last 2 decades, especially in cancer theranostics. Due to the unique features of NMOFs, including structural diversities, enormous porosity, multifunctionality and biocompatibility, they have been widely used to deliver imaging contrast agents and therapeutic drugs. Moreover, multiple types of contrast agents, anti-cancer drugs and targeting ligands could be co-delivered through one single NMOF to enable combination therapy. Co-delivering system using NMOFs helped to avoid multidrug resistance, to reduce adverse effects, to achieve imaging-guided precise therapy and to enhance anti-cancer efficacy. This review summarized the recent research advances on the application of NMOFs in biomedical imaging and cancer treatments in the last few years. The current challenges that impeding their translation to clinical practices and the perspectives for their future applications were also highlighted and discussed.

Nano-immunotherapy: Overcoming tumour immune evasion

Immunotherapy is emerging as a groundbreaking cancer treatment, offering the unprecedented opportunity to effectively treat and in several cases, even cure previously untreatable malignancies. Anti-tumour immunotherapies designed to amplify T cell responses against defined tumour antigens have long been considered effective approaches for cancer treatment. Despite a clear rationale behind such immunotherapies, extensive past efforts were unsuccessful in mediating clinically relevant anti-tumour activity in humans. This is mainly because tumours adopt specific mechanisms to circumvent the host´s immunity. Emerging data suggest that the full potential of cancer immunotherapy will be only achieved by combining immunotherapies designed to generate or amplify anti-tumour T cell responses with strategies able to impair key tumour immune-evasion mechanisms. However, many approaches aimed to re-shape the tumour immune microenvironment (TIME) are commonly associated with severe systemic toxicity, require frequent administration, and only show modest efficacy in clinical settings. The use of nanodelivery systems is revealing as a valid means to overcome these limitations by improving the targeting efficiency, minimising systemic exposure of immunomodulatory agents, and enabling the development of novel combinatorial immunotherapies. In this review, we examine the emerging field of therapeutic modulation of TIME by the use of nanoparticle-based immunomodulators and potential future directions for TIME-targeting nanotherapies.

Au nanoparticles with enzyme-mimicking activity-ornamented ZIF-8 for highly efficient photodynamic therapy

The tumor hypoxic microenvironment (THME) has a profound impact on tumor progression, and modulation of the THME has become an essential strategy to promote photodynamic therapy (PDT). Here, an oxygen self-supplied nanodelivery system that is based on nanometal-organic frameworks (nMOFs) with embedded AuNPs (Au@ZIF-8) on the nMOF surface as a catalase (CAT)-like nanozyme and encapsulating Ce6 inside as a photosensitizer was found to mitigate tumor hypoxia and reinforce PDT. As soon as Au@ZIF-8 reaches the tumor site, the AuNP nanozyme can catalyze excessive H2O2 to produce O2 to alleviate tumor hypoxia, promoting the production of 1O2 with strong toxicity toward tumor cells under irradiation. Our study demonstrates that nMOFs embellished with a nanozyme have great potential for overcoming the THME for cancer therapeutics, which provides a facile strategy for accurate bioimaging and cancer therapy in vivo.

Elucidating J-Aggregation Effect in Boosting Singlet-Oxygen Evolution Using Zirconium-Porphyrin Frameworks: A Comprehensive Structural, Catalytic, and Spectroscopic Study

Metal-organic frameworks (MOFs) are powerful toolkits to directly correlate structure-function relationships due to their well-defined structures. In this work, 5,15-di(3,4,5-trihydroxyphenyl)porphyrin (DTPP) and 5,10,15,20-tetra(3,4,5-trihydroxyphenyl)porphyrin (TTPP) are reacted with zirconium ions to afford two MOFs (Zr-DTPP and Zr-TTPP) with acid and base tolerance in the pH range of 1.0-14.0. Powder X-ray diffraction investigation combined with Rietveld refinement reveals the J-aggregated porphyrin building blocks confined by benzene-1,2,3-trisolate-zirconium chains in the newly prepared Zr-DTPP. Electron spin-resonance, singlet-oxygen determination, and sulfides oxidation experiments demonstrate a much better singlet-oxygen evolution of J-aggregated Zr-DTPP than that of unaggregated Zr-TTPP reported previously, in good contrast to the weaker photocatalytic capability disclosed for DTPP than that for TTPP in solution, consummating the theory of photosensitizer J-aggregation in boosting heterogeneous photoinduced singlet-oxygen generation.

Massively Evoking Immunogenic Cell Death by Focused Mitochondrial Oxidative Stress using an AIE Luminogen with a Twisted Molecular Structure

Immunogenic cell death (ICD) provides momentous theoretical principle for modern cancer immunotherapy. However, the currently available ICD inducers are still very limited and photosensitizer-based ones can hardly induce sufficient ICD to achieve satisfactory cancer immunotherapy by themselves. Herein, an organic photosensitizer (named TPE-DPA-TCyP) with a twisted molecular structure, strong aggregation-induced emission activity, and specific ability is reported for effectively inducing focused mitochondrial oxidative stress of cancer cells, which can serve as a much superior ICD inducer to the popularly used ones, including chlorin e6 (Ce6), pheophorbide A, and oxaliplatin. Furthermore, more effective in vivo ICD immunogenicity of TPE-DPA-TCyP than Ce6 is also demonstrated using a prophylactic tumor vaccination model. The underlying mechanism of the effectiveness and robustness of TPE-DPA-TCyP in inducing antitumor immunity and immune-memory effect in vivo is verified by immune cell analyses. This study thus reveals that inducing focused mitochondrial oxidative stress is a highly effective strategy to evoke abundant and large-scale ICD.

Advanced Nanotechnology Leading the Way to Multimodal Imaging-Guided Precision Surgical Therapy

Surgical resection is the primary and most effective treatment for most patients with solid tumors. However, patients suffer from postoperative recurrence and metastasis. In the past years, emerging nanotechnology has led the way to minimally invasive, precision and intelligent oncological surgery after the rapid development of minimally invasive surgical technology. Advanced nanotechnology in the construction of nanomaterials (NMs) for precision imaging-guided surgery (IGS) as well as surgery-assisted synergistic therapy is summarized, thereby unlocking the advantages of nanotechnology in multimodal IGS-assisted precision synergistic cancer therapy. First, mechanisms and principles of NMs to surgical targets are briefly introduced. Multimodal imaging based on molecular imaging technologies provides a practical method to achieve intraoperative visualization with high resolution and deep tissue penetration. Moreover, multifunctional NMs synergize surgery with adjuvant therapy (e.g., chemotherapy, immunotherapy, phototherapy) to eliminate residual lesions. Finally, key issues in the development of ideal theranostic NMs associated with surgical applications and challenges of clinical transformation are discussed to push forward further development of NMs for multimodal IGS-assisted precision synergistic cancer therapy.

Recent Advances in Glucose-Oxidase-Based Nanocomposites for Tumor Therapy

Glucose oxidase (GOx) can react with intracellular glucose and oxygen (O₂ ) to produce hydrogen peroxide (H₂ O₂ ) and gluconic acid, which can cut off the nutrition source of cancer cells and consequently inhibit their proliferation. Therefore, GOx is recognised as an ideal endogenous oxido-reductase for cancer starvation therapy. This process can further regulate the tumor microenvironment by increasing the hypoxia and the acidity. Thus, GOx offers new possibilities for the elaborate design of multifunctional nanocomposites for tumor therapy. However, natural GOx is expensive to prepare and purify and exhibits immunogenicity, short in vivo half-life, and systemic toxicity. Furthermore, GOx is highly prone to degrade after exposure to biological conditions. These intrinsic shortcomings will undoubtedly limit its biomedical applications. Accordingly, some nanocarriers can be used to protect GOx from the surrounding environment, thus controlling or preserving the activity. A variety of nanocarriers including hollow mesoporous silica nanoparticles, metal-organic frameworks, organic polymers, and magnetic nanoparticles are summarized for the construction of GOx-based nanocomposites for multimodal synergistic cancer therapy. In addition, current challenges and promising developments in this area are highlighted.

Immune Checkpoint Blockade Mediated by a Small-Molecule Nanoinhibitor Targeting the PD-1/PD-L1 Pathway Synergizes with Photodynamic Therapy to Elicit Antitumor Immunity and Antimetastatic Effects on Breast Cancer

Targeting programmed cell death protein 1 (PD-1)/programmed death ligand 1 (PD-L1) immunologic checkpoint blockade with monoclonal antibodies has achieved recent clinical success in antitumor therapy. However, therapeutic antibodies exhibit several issues such as limited tumor penetration, immunogenicity, and costly production. Here, Bristol-Myers Squibb nanoparticles (NPs) are prepared using a reprecipitation method. The NPs have advantages including passive targeting, hydrophilic and nontoxic features, and a 100% drug loading rate. BMS-202 is a small-molecule inhibitor of the PD-1/PD-L1 interaction that is developed by BMS. Transfer of BMS-202 NPs to 4T1 tumor-bearing mice results in markedly slower tumor growth to the same degree as treatment with anti-PD-L1 monoclonal antibody (α-PD-L1). Consistently, the combination of Ce6 NPs with BMS-202 NPs or α-PD-L1 in parallel shows more efficacious antitumor and antimetastatic effects, accompanied by enhanced dendritic cell maturation and infiltration of antigen-specific T cells into the tumors. Thus, inhibition rates of primary and distant tumors reach >90%. In addition, BMS-202 NPs are able to attack spreading metastatic lung tumors and offer immune-memory protection to prevent tumor relapse. These results indicate that BMS-202 NPs possess effects similar to α-PD-L1 in the therapies of 4T1 tumors. Therefore, this work reveals the possibility of replacing the antibody used in immunotherapy for tumors with BMS-202 NPs.

Co-delivery of Bee Venom Melittin and a Photosensitizer with an Organic-Inorganic Hybrid Nanocarrier for Photodynamic Therapy and Immunotherapy

Photodynamic therapy (PDT) is a clinical cancer treatment modality based on the induction of therapeutic reactive oxygen species (ROS), which can trigger immunogenic cell death (ICD). With the aim of simultaneously improving both PDT-mediated intracellular ROS production and ICD levels, we designed a serum albumin (SA)-coated boehmite ("B"; aluminum hydroxide oxide) organic-inorganic scaffold that could be loaded with chlorin e6 (Ce6), a photosensitizer, and a honey bee venom melittin (MLT) peptide, denoted Ce6/MLT@SAB. Ce6/MLT@SAB was anchored by a boehmite nanorod structure and exhibited particle size of approximately 180 nm. Ce6/MLT@SAB could significantly reduce hemolysis relative to that of free MLT, while providing MLT-enhanced PDT antitumor effects in vitro. Compared with Ce6@SAB, Ce6/MLT@SAB improved Ce6 penetration of cancer cells both in vitro and in vivo, thereby providing enhanced intracellular ROS generation with 660 nm light treatment. Following phototreatment, Ce6/MLT@SAB-treated cells displayed significantly improved levels of ICD and abilities to activate dendritic cells. In the absence of laser irradiation, multidose injection of Ce6/MLT@SAB could delay the growth of subcutaneous murine tumors by more than 60%, compared to controls. When combined with laser irradiation, a single injection and phototreatment with Ce6/MLT@SAB eradicated one-third of subcutaneous tumors in treated mice. The addition of an immune checkpoint blockade to Ce6/MLT@SAB phototreatment further augmented antitumor effects, generating increased numbers of CD4⁺ and CD8⁺ T cells in tumors with concomitant reduction of myeloid-derived suppressor cells.

Task-Specific Design of Immune-Augmented Nanoplatform to Enable High-Efficiency Tumor Immunotherapy

Potentiating systemic immunity against breast cancer is in the most urgent demand as breast cancer is less sensitive to immune checkpoint blockade. Although phototherapy and some chemotherapy can trigger immunogenic cell death (ICD) for T cell-mediated antitumor immune response, their immunotherapy efficacy is severely restricted by insufficient phototherapeutic capability and severe multidrug resistance (MDR). Inspired by both the hypersensitivity to phototherapy and the key role of MDR for mitochondria, a rationally engineered immunity amplifier via mitochondria-targeted photochemotherapeutic nanoparticles was, for the first time, achieved to fight against low-immunogenic breast cancer without additional immune agents. The newly synthesized task-specific mitochondria-targeted IR780 derivative (T780) was integrated with chemotherapeutic doxorubicin (DOX) to form multifunctional nanoparticles via an assembling strategy along with bovine serum albumin (BSA) as a biomimetic corona (BSA@T780/DOX NPs). The in situ enhancement in both phototherapy and MDR reversal by targeting mitochondria with BSA@T780/DOX NPs boosted highly efficient ICD toward excellent antitumor immune response. The newly developed strategy not only eradicated the primary tumor but also eliminated the bilateral tumors efficiently, as well as preventing metastasis and postsurgical recurrence, demonstrating great interest for fighting against low-immunogenic breast cancer.