Artificial Engineered Natural Killer Cells Combined with Antiheat Endurance as a Powerful Strategy for Enhancing Photothermal-Immunotherapy Efficiency of Solid Tumors

Targeting the tumor microenvironment with biomaterials for enhanced immunotherapeutic efficacy

The tumor microenvironment (TME) is a complex system characterized by low oxygen, low pH, high pressure, and numerous growth factors and protein hydrolases that regulate a wide range of biological behaviors in the tumor and have a profound impact on cancer progression. Immunotherapy is an innovative approach to cancer treatment that activates the immune system, resulting in the spontaneous killing of tumor cells. However, the therapeutic efficacy of these clinically approved cancer immunotherapies (e.g., immune checkpoint blocker (ICB) therapies and chimeric antigen receptor (CAR) T-cell therapies) is far from satisfactory due to the presence of immunosuppressive TMEs created in part by tumor hypoxia, acidity, high levels of reactive oxygen species (ROS), and a dense extracellular matrix (ECM). With continuous advances in materials science and drug-delivery technologies, biomaterials hold considerable potential for targeting the TME. This article reviews the advances in biomaterial-based targeting of the TME to advance our current understanding on the role of biomaterials in enhancing tumor immunity. In addition, the strategies for remodeling the TME offer enticing advantages; however, the represent a double-edged sword. In the process of reshaping the TME, the risk of tumor growth, infiltration, and distant metastasis may increase.

Recent advances in DNAzymes for bioimaging, biosensing and cancer therapy

DNAzymes, a class of single-stranded catalytic DNA with good stability, high catalytic activity, and easy synthesis, functionalization and modification properties, have garnered significant interest in the realm of biosensing and bioimaging. Their integration with fluorescent dyes or chemiluminescent moieties has led to remarkable bioimaging outcomes, while DNAzyme-based biosensors have demonstrated robust sensitivity and selectivity in detecting metal ions, nucleic acids, proteins, enzyme activities, exosomes, bacteria and microorganisms. In addition, by delivering DNAzymes into tumor cells, the mRNA therein can be cleaved to regulate the expression of corresponding proteins, which has further propelled the application of DNAzymes in cancer gene therapy and synergistic therapy. This paper reviews the strategies for screening attractive DNAzymes such as SELEX and high-throughput sequencing, and briefly describes the amplification strategies of DNAzymes, which mainly include catalytic hairpin assembly (CHA), DNA walker, hybridization chain reaction (HCR), DNA origami, CRISPR-Cas12a, rolling circle amplification (RCA), and aptamers. In addition, applications of DNAzymes in bioimaging, biosensing, and cancer therapy are also highlighted. Subsequently, the possible challenges of these DNAzymes in practical applications are further pointed out, and future research directions are suggested.

Construction of polypyrrole nanoparticles with a rough surface for enhanced chemo-photothermal therapy against triple negative breast cancer

Triple-negative breast cancer (TNBC) is the most malignant subtype of breast cancer, characterized by aggressive malignancy and a poor prognosis. Emerging nanomedicine-based combination therapy represents one of the most promising strategies for combating TNBC. Polypyrrole nanoparticles (PPY) are excellent drug delivery vehicles with outstanding photothermal performances. However, the impact of morphology on PPY's drug loading efficiency and photothermal properties remains largely unexplored. In this study, we propose that pluronic P123 can assist in the synthesis of polypyrrole nanoparticles with rough surfaces (rPPY). During the synthesis, P123 formed small micelles around the nanoparticle surface, which were later removed, resulting in small pits and cavities in rPPY. Subsequently, the rPPY was loaded with the chemotherapy drug gemcitabine (Gem@rPPY) for chemo-photothermal therapy against TNBCs. Our results demonstrate that rPPY exhibited superior photothermal performance and significantly enhanced drug loading efficiency by five times compared to smooth PPY nanoparticles. In vitro assessments confirmed Gem@rPPY's robust photothermal properties by efficiently converting light into heat. Cell culture experiments with 4T1 cells and a TNBC mice model revealed significant tumor suppression upon Gem@rPPY administration, emphasizing its efficacy in inducing apoptosis. Toxicity evaluations demonstrated minimal adverse effects both in vitro and in vivo, highlighting the biocompatibility of Gem@rPPY. Overall, this study introduces a promising combination therapy nanoplatform that underscores the importance of surface engineering to enhance therapeutic outcomes and overcome current limitations in TNBC therapy.

Advances and perspectives in phototherapy-based combination therapy for cancer treatment

Phototherapy, including photothermal therapy (PTT) and photodynamic therapy (PDT), has the advantages of spatiotemporal selectivity, non-invasiveness, and negligible drug resistance. Phototherapy has been approved for treating superficial epidermal tumors. However, its therapeutic efficacy is limited by the hypoxic tumor microenvironment and the highly expressed heat shock protein. Moreover, poor tissue penetration and focused irradiation laser region in phototherapy make treating deep tissues and metastatic tumors challenging. Combination therapy strategies, which integrate the advantages of each treatment and overcome their disadvantages, can significantly improve the therapeutic efficacy. Recently, many combination therapy strategies have been reported. Our study summarizes the strategies used for combining phototherapy with other cancer treatments such as chemotherapy, immunotherapy, sonodynamic therapy, gas therapy, starvation therapy, and chemodynamic therapy. Some research cases were selected to analyze the combination therapy effect, delivery platform feature, and synergetic anticancer mechanisms. Moreover, additional research cases are summarized in the tables. This review provides strong evidence that phototherapy-based combination strategies can enhance the anticancer effect compared with phototherapy alone. Additionally, the challenges and future perspectives associated with these combinational therapies are discussed.

Natural killer cell-derived exosome-based cancer therapy: from biological roles to clinical significance and implications

Natural killer (NK) cells are important immune cells in the organism and are the third major type of lymphocytes besides T cells and B cells, which play an important function in cancer therapy. In addition to retaining the tumor cell killing function of natural killer cells, natural killer cell-derived exosomes cells also have the characteristics of high safety, wide source, easy to preserve and transport. At the same time, natural killer cell-derived exosomes are easy to modify, and the engineered exosomes can be used in combination with a variety of current cancer therapies, which not only enhances the therapeutic efficacy, but also significantly reduces the side effects. Therefore, this review summarizes the source, isolation and modification strategies of natural killer cell-derived exosomes and the combined application of natural killer cell-derived engineered exosomes with other antitumor therapies, which is expected to accelerate the clinical translation process of natural killer cell-derived engineered exosomes in cancer therapy.

Gold(III) Porphyrin-Metal-Polyphenolic Nanocomplexes: Breaking Intracellular Redox Environment for Enhancing Mild-Temperature Photothermal Therapy

Photothermal therapy (PTT) is a promising clinical antitumor strategy. However, local hyperthermia inevitably induces heat damage to adjacent normal tissues, while alternative mild-temperature therapy (MPTT, T < 45 °C) is also inefficient due to the overexpressed hyperthermia-induced heat shock proteins (HSPs) by cancer cells. Therefore, developing PTT strategies with minimizing damage to healthy tissues with improved cellular temperature sensitivity is extremely valuable for clinical application. Herein, we proposed the strategy of disrupting the intracellular redox environment via destroying the ROS-defending systems to promote MPTT. The gold(III) porphyrin-Fe3+-tannic acid nanocomplexes (AuTPP@TA-Fe NPs) were achieved via interfacial cohesion and supramolecular assembly of bioadhesive species, which could trigger the Fenton reaction to produce ·OH radicals and downregulation of reductive TrxR enzyme and mitochondrial chaperone protein Hsp60. The aggravation of oxides and the inactivation of Hsp60 provide favorable pathways for impeding the heat shock-induced self-repair mechanism of cancer cells, which strengthens AuTPP@TA-Fe NPs mediated MPTT.

The Emerging Landscape for Combating Resistance Associated with Energy-Based Therapies via Nanomedicine

Cancer represents a serious disease with significant implications for public health, imposing substantial economic burden and negative societal consequences. Compared to conventional cancer treatments, such as surgery and chemotherapy, energy-based therapies (ET) based on athermal and thermal ablation provide distinct advantages, including minimally invasive procedures and rapid postoperative recovery. Nevertheless, due to the complex pathophysiology of many solid tumors, the therapeutic effectiveness of ET is often limited. Nanotechnology offers unique opportunities by enabling facile material designs, tunable physicochemical properties, and excellent biocompatibility, thereby further augmenting the outcomes of ET. Numerous nanomaterials have demonstrated the ability to overcome intrinsic therapeutic resistance associated with ET, leading to improved antitumor responses. This comprehensive review systematically summarizes the underlying mechanisms of ET-associated resistance (ETR) and highlights representative applications of nanoplatforms used to mitigate ETR. Overall, this review emphasizes the recent advances in the field and presents a detailed account of novel nanomaterial designs in combating ETR, along with efforts aimed at facilitating their clinical translation.

Cellular-Membrane-Derived Vesicles for Cancer Immunotherapy

The medical community is constantly searching for new and innovative ways to treat cancer, and cellular-membrane-derived artificial vesicles are emerging as a promising avenue for cancer immunotherapy. These vesicles, which are derived from mammal and bacteria cell membranes, offer a range of benefits, including compatibility with living organisms, minimal immune response, and prolonged circulation. By modifying their surface, manipulating their genes, combining them with other substances, stimulating them externally, and even enclosing drugs within them, cellular vesicles have the potential to be a powerful tool in fighting cancer. The ability to merge drugs with diverse compositions and functionalities in a localized area is particularly exciting, as it offers a way to combine different immunotherapy treatments for maximum impact. This review contains information on the various sources of these vesicles and discusses some recent developments in cancer immunotherapy using this promising technology. While there are still obstacles to overcome, the possibilities for cellular vesicles in cancer treatment are truly exciting.

Alum-tuned hyaluronic acid-based hydrogel with immune checkpoint inhibition for immunophoto therapy of cancer

Alum-crosslinked hyaluronic acid-dopamine (HD) hydrogel containing indocyanine green (ICG) with anti-programmed cell death-1 (PD-1) antibody (Ab) administration was developed for immunophoto therapy of cancer. Alum modulates the rheological characteristics of hydrogel for enabling syringe injection, shear-thinning feature, and slower biodegradation. In addition, alum in HD-based hydrogel provided CD8+ T cell-mediated immune responses for cancer therapy. ICG in the hydrogel under near-infrared (NIR) light exposure may induce hyperthermia and generate singlet oxygen for selective cancer cell killing. HD/alum/ICG hydrogel injection with NIR laser irradiation elevated PD-1 level in CD8+ T cells. Administration of PD-1 Ab aiming at highly expressed PD-1 in T cells may amplify the anticancer efficacies of HD/alum/ICG hydrogel along with NIR laser. HD/alum/ICG hydrogel with NIR light may have both CD8+ T cell-linked immune responses and ICG-related photodynamic/photothermal effects. Additional injection of immune checkpoint inhibitor can ultimately suppress primary and distant tumor growth by combination with those therapeutic actions.

Natural killer cells modified with a Gpc3 aptamer enhance adoptive immunotherapy for hepatocellular carcinoma

INTRODUCTION

Natural killer cells can attack cancer cells without prior sensitization, but their clinical benefit is limited owing to their poor selectivity that is caused by the lack of specific receptors to target tumor cells. In this study, we aimed to endow NK cells with the ability to specifically target glypican-3+ tumor cells without producing cell damage or genetic alterations, and further evaluated their therapeutic efficiency.

METHODS

NK cells were modified with a Gpc3 DNA aptamer on the cell surface via metabolic glycoengineering to endow NK cells with specific targeting ability. Then, the G-NK cells were evaluated for their specific targeting properties, cytotoxicity and secretion of cytokines in vitro. Finally, we investigated the therapeutic efficiency of G-NK cells against glypican-3+ tumor cells in vivo.

RESULTS

Compared with NK cells modified with a random aptamer mutation and unmodified NK cells, G-NK cells induced significant apoptosis/necrosis of GPC3+ tumor cells and secreted cytokines to preserve the intense cytotoxic activities. Moreover, G-NK cells significantly suppressed tumor growth in HepG2 tumor-bearing mice due to the enhanced enrichment of G-NK cells at the tumor site.

CONCLUSIONS

The proposed strategy endows NK cells with a tumor-specific targeting ability to enhance adoptive therapeutic efficiency in GPC3+ hepatocellular carcinoma.

Polymeric biomaterial-inspired cell surface modulation for the development of novel anticancer therapeutics

Immune cell-based therapies are a rapidly emerging class of new medicines that directly treat and prevent targeted cancer. However multiple biological barriers impede the activity of live immune cells, and therefore necessitate the use of surface-modified immune cells for cancer prevention. Synthetic and/or natural biomaterials represent the leading approach for immune cell surface modulation. Different types of biomaterials can be applied to cell surface membranes through hydrophobic insertion, layer-by-layer attachment, and covalent conjugations to acquire surface modification in mammalian cells. These biomaterials generate reciprocity to enable cell-cell interactions. In this review, we highlight the different biomaterials (lipidic and polymeric)-based advanced applications for cell-surface modulation, a few cell recognition moieties, and how their interplay in cell-cell interaction. We discuss the cancer-killing efficacy of NK cells, followed by their surface engineering for cancer treatment. Ultimately, this review connects biomaterials and biologically active NK cells that play key roles in cancer immunotherapy applications.

Manganese-Based Tumor Immunotherapy

As an essential micronutrient, manganese (Mn) participates in various physiological processes and plays important roles in host immune system, hematopoiesis, endocrine function, and oxidative stress regulation. Mn-based nanoparticles are considered to be biocompatible and show versatile applications in nanomedicine, in particular utilized in tumor immunotherapy in the following ways: 1) acting as a biocompatible nanocarrier to deliver immunotherapeutic agents for tumor immunotherapy; 2) serving as an adjuvant to regulate tumor immune microenvironment and enhance immunotherapy; 3) activating host's immune system through the cGAS-STING pathway to trigger tumor immunotherapy; 4) real-time monitoring tumor immunotherapy effect by magnetic resonance imaging (MRI) since Mn²⁺ ions are ideal MRI contrast agent which can significantly enhance the T₁ -weighted MRI signal after binding to proteins. This comprehensive review focuses on the most recent progress of Mn-based nanoplatforms in tumor immunotherapy. The characteristics of Mn are first discussed to guide the design of Mn-based multifunctional nanoplatforms. Then the biomedical applications of Mn-based nanoplatforms, including immunotherapy alone, immunotherapy-involved multimodal synergistic therapy, and imaging-guided immunotherapy are discussed in detail. Finally, the challenges and future developments of Mn-based tumor immunotherapy are highlighted.

Normalization of Tumor Vessels by Lenvatinib-Based Metallo-Nanodrugs Alleviates Hypoxia and Enhances Calreticulin-Mediated Immune Responses in Orthotopic HCC and Organoids

Immunocheckpoint inhibitors combined with Lenvatinib is the first line treatment for hepatocellular carcinoma (HCC), but their potency is hampered by the low response rate and adverse events. Herein, a targeted therapeutic strategy through the coassembly of Lenvatinib, Adriamycin, Fe³⁺ ion, and a natural polyphenol (metallo-nanodrugs) is presented by coordination effect for potentiating tumor vascular normalization and systematic chemo-immunotherapy to effectively inhibit the progression of HCC in both orthotopic model and patients-derived organoids. In mice with orthotopic HCC, the obtained metallo-nanodrugs efficiently increase the drug accumulation in orthotopic tumors and can respond to acidic tumor environment. The promotion of tumor vascular normalization by metallo-nanodrugs is observed, which enhances the infiltrating T lymphocytes in tumor, and reinforces the calreticulin-mediated antitumor immunity through alleviating hypoxia, reducing regulatory T cells, and down-regulating PDL1 expression of tumors. The excellent therapeutic efficiency with complete remission of orthotopic tumors (3/6) and long-term survival of mice (4/6, 42 days) are also achieved. Furthermore, the excellent therapeutic effect of metallo-nanodrugs is also validated in 5 patient-derived organoids, and hence can provide a marvelous systemic chemo-immunotherapy strategy for enhancing HCC treatment.

Harnessing Engineered Immune Cells and Bacteria as Drug Carriers for Cancer Immunotherapy

Immunotherapy continues to be in the spotlight of oncology therapy research in the past few years and has been proven to be a promising option to modulate one's innate and adaptive immune systems for cancer treatment. However, the poor delivery efficiency of immune agents, potential off-target toxicity, and nonimmunogenic tumors significantly limit its effectiveness and extensive application. Recently, emerging biomaterial-based drug carriers, including but not limited to immune cells and bacteria, are expected to be potential candidates to break the dilemma of immunotherapy, with their excellent natures of intrinsic tumor tropism and immunomodulatory activity. More than that, the tiny vesicles and physiological components derived from them have similar functions with their source cells due to the inheritance of various surface signal molecules and proteins. Herein, we presented representative examples about the latest advances of biomaterial-based delivery systems employed in cancer immunotherapy, including immune cells, bacteria, and their derivatives. Simultaneously, opportunities and challenges of immune cells and bacteria-based carriers are discussed to provide reference for their future application in cancer immunotherapy.

Buffet-style Cu(II) for enhance disulfiram-based cancer therapy

Studies have shown that disulfiram (DSF) can combine with Cu²⁺ to form bis(N, N-diethyldithiocarbamate) copper(II) complex (CuET) as antitumor drugs. However, there is insufficient endogenous Cu²⁺ dose to eradicate cancer cells selectively. Inspired by the buffet, we use Cu²⁺ doped hollow zeolitic imidazolate framework nanoparticles (HZIF_Cu) as the carrier and equipped with DSF and indocyanine green (ICG) and targeted by folic acid (FA) (D&I@HZIF_Cu-FA) to enhance DSF-based cancer therapy. D&I@HZIF_Cu-FA could effectively supply Cu²⁺ by a buffet-style, assisting the "DSF-to-CuET" transformation in the tumor. Additionally, self-supply Cu²⁺ could convert H₂O₂ into ·OH by triggering a Fenton-like reaction for chemo-dynamic therapy, and ICG achieves photothermal therapy for tumors under laser irradiation. This work provides a buffet-style for Cu²⁺ to make DSF a strong candidate for cancer treatment by combining chemotherapy, chemo-dynamic therapy, and photothermal therapy and inspires more research about its applications in tumor therapy.

Vehicle-Free Nanotheranostic Self-Assembled from Clinically Approved Dyes for Cancer Fluorescence Imaging and Photothermal/Photodynamic Combinational Therapy

Phototherapy, including photothermal therapy (PTT) and photodynamic therapy (PDT) has attracted growing attention as a noninvasive option for cancer treatment. At present, researchers have developed various "all-in-one" nanoplatforms for cancer imaging and PTT/PDT combinational therapy. However, the complex structure, tedious preparation procedures, overuse of extra carriers and severe side effects hinder their biomedical applications. In this work, we reported a nanoplatform (designated as ICG-MB) self-assembly from two different FDA-approved dyes of indocyanine green (ICG) and methylene blue (MB) without any additional excipients for cancer fluorescence imaging and combinational PTT/PDT. ICG-MB was found to exhibit good dispersion in the aqueous phase and improve the photostability and cellular uptake of free ICG and MB, thus exhibiting enhanced photothermal conversion and singlet oxygen (1O2) generation abilities to robustly ablate cancer cells under 808 nm and 670 nm laser irradiation. After intravenous injection, ICG-MB effectively accumulated at tumor sites with a near-infrared (NIR) fluorescence signal, which helped to delineate the targeted area for NIR laser-triggered phototoxicity. As a consequence, ICG-MB displayed a combinational PTT/PDT effect to potently inhibit tumor growth without causing any system toxicities in vivo. In conclusion, this minimalist, effective and biocompatible nanotheranostic would provide a promising candidate for cancer phototherapy based on current available dyes in clinic.

Biomimetic and Materials-Potentiated Cell Engineering for Cancer Immunotherapy

In cancer immunotherapy, immune cells are the main force for tumor eradication. However, they appear to be dysfunctional due to the taming of the tumor immunosuppressive microenvironment. Recently, many materials-engineered strategies are proposed to enhance the anti-tumor effect of immune cells. These strategies either utilize biomimetic materials, as building blocks to construct inanimate entities whose functions are similar to natural living cells, or engineer immune cells with functional materials, to potentiate their anti-tumor effects. In this review, we will summarize these advanced strategies in different cell types, as well as discussing the prospects of this field.

Recent advances of engineered and artificial drug delivery system towards solid tumor based on immune cells

Precise drug delivery in cancer treatment is a long-standing concern of modern medicine. Compared with traditional molecular medicines and nano-medicines, emerging cell-based biomimetic delivery strategies display numerous merits, including successive biological functions, innate biocompatibility and superior security since they originate from living organisms, providing a very promising approach. Among them, immune cells receive increasing attention because of their inherent ability in tumor resistance, pathogen elimination, and other significant physiological functions. Herein, we investigated the recent advances on immune cell-based high efficient delivery and therapeutic strategies in solid tumor treatment, mainly focus on T cells, NK cells and macrophages, which have been used as drug cargos directly or provided membrane/exosomes as nanoscale drug delivery systems. We also discuss the further potential applications and perspective of this innovative strategy, as well as the predictable challenges in forward exploration in this emerging area.

Combination of Ablation and Immunotherapy for Hepatocellular Carcinoma: Where We Are and Where to Go

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related deaths worldwide and is increasing in incidence. Local ablative therapy plays a leading role in HCC treatment. Radiofrequency (RFA) is one of the first-line therapies for early local ablation. Other local ablation techniques (e.g., microwave ablation, cryoablation, irreversible electroporation, phototherapy.) have been extensively explored in clinical trials or cell/animal studies but have not yet been established as a standard treatment or applied clinically. On the one hand, single treatment may not meet the needs. On the other hand, ablative therapy can stimulate local and systemic immune effects. The combination strategy of immunotherapy and ablation is reasonable. In this review, we briefly summarized the current status and progress of ablation and immunotherapy for HCC. The immune effects of local ablation and the strategies of combination therapy, especially synergistic strategies based on biomedical materials, were discussed. This review is hoped to provide references for future researches on ablative immunotherapy to arrive to a promising new era of HCC treatment.

Recent advances in selective photothermal therapy of tumor

Photothermal therapy (PTT), which converts light energy to heat energy, has become a new research hotspot in cancer treatment. Although researchers have investigated various ways to improve the efficiency of tumor heat ablation to treat cancer, PTT may cause severe damage to normal tissue due to the systemic distribution of photothermal agents (PTAs) in the body and inaccurate laser exposure during treatment. To further improve the survival rate of cancer patients and reduce possible side effects on other parts of the body, it is still necessary to explore PTAs with high selectivity and precise treatment. In this review, we summarized strategies to improve the treatment selectivity of PTT, such as increasing the accumulation of PTAs at tumor sites and endowing PTAs with a self-regulating photothermal conversion function. The views and challenges of selective PTT were discussed, especially the prospects and challenges of their clinical applications.

Temperature-Feedback Nanoplatform for NIR-II Penta-Modal Imaging-Guided Synergistic Photothermal Therapy and CAR-NK Immunotherapy of Lung Cancer

In this study, to visually acquire all-round structural and functional information of lung cancer while performing synergistic photothermal therapy (PTT) and tumor-targeting immunotherapy, a theranostic nanoplatform that introduced upconversion nanoparticles (UCNPs) and IR-1048 dye into the lipid-aptamer nanostructrure (UCILA) is constructed. Interestingly, the IR-1048 dye grafted into the lipid bilayer can serve as the theranostic agent for photoacoustic imaging, optical coherence tomography angiography, photothermal imaging, and PTT in the second near infrared (NIR-II) window. In addition, loaded in the inner part of UCILA, UCNPs possess the superior luminescence property and high X-ray attenuation coefficient, which can act as contrast agents for computed tomography (CT) and thermo-sensitive up-conversion luminescence (UCL) imaging, enabling real-time tracking of metabolic activity of tumor and temperature-feedback PTT. Furthermore, under the complementary guidance of penta-modal imaging and an accurate monitoring of in situ temperature change during PTT, UCILA exhibits its excellent capability for ablating the lung tumor with minimal side effects. Meanwhile, synergistic CAR-NK immunotherapy is carried out specifically to eradicate any possible residual tumor cells after PTT. Therefore, the UCILA nanoplatform is demonstrated as a multifunctional theranostic agent for both penta-modal imaging and temperature-feedback PTT while conducting targeting immunotherapy of lung cancer.

Recent Advances in Engineered Materials for Immunotherapy-Involved Combination Cancer Therapy

Immunotherapy that can activate immunity or enhance the immunogenicity of tumors has emerged as one of the most effective methods for cancer therapy. Nevertheless, single-mode immunotherapy is still confronted with several critical challenges, such as the low immune response, the low tumor infiltration, and the complex immunosuppression tumor microenvironment. Recently, the combination of immunotherapy with other therapeutic modalities has emerged as a powerful strategy to augment the therapeutic outcome in fighting against cancer. In this review, recent research advances of the combination of immunotherapy with chemotherapy, phototherapy, radiotherapy, sonodynamic therapy, metabolic therapy, and microwave thermotherapy are summarized. Critical challenges and future research direction of immunotherapy-based cancer therapeutic strategy are also discussed.

Redirecting natural killer cells to potentiate adoptive immunotherapy in solid tumors through stabilized Y-type bispecific aptamer

Modulating interactions between immune effector cells and tumor cells in vivo using a bispecific aptamer (Ap) is a promising strategy for cancer immunotherapy. However, it remains a technical challenge owing to the complex and dynamic internal environment accompanied by severe degradation. Herein, by using a Y-shaped DNA scaffold, a bispecific and stabilized Y-type Ap is designed to redirect natural killer (NK) cells to enhance adoptive immunotherapy of hepatocellular carcinoma (HCC) solid tumors. Y-type Ap is constituted by the HCC-specific Ap TLS11a linked with the CD16-specific Ap through a Y-shaped DNA scaffold. Owing to the rigid structure, Y-type Ap shows high stability in 10% serum for over 72 h and resistance to denaturation by 8 M urea. Additionally, the Y-type Ap exhibits more potent avidity to bind with NK cells and tumor cells both in vitro and in vivo, resulting in higher cytokine secretion and excellent antitumor efficiency. Collectively, this study offers a translational platform for constructing stable bispecific Ap, offering considerable potential to enhance adoptive immunotherapy of solid tumors.

Chemically Engineered Immune Cell-Derived Microrobots and Biomimetic Nanoparticles: Emerging Biodiagnostic and Therapeutic Tools

Over the past decades, considerable attention has been dedicated to the exploitation of diverse immune cells as therapeutic and/or diagnostic cell-based microrobots for hard-to-treat disorders. To date, a plethora of therapeutics based on alive immune cells, surface-engineered immune cells, immunocytes' cell membranes, leukocyte-derived extracellular vesicles or exosomes, and artificial immune cells have been investigated and a few have been introduced into the market. These systems take advantage of the unique characteristics and functions of immune cells, including their presence in circulating blood and various tissues, complex crosstalk properties, high affinity to different self and foreign markers, unique potential of their on-demand navigation and activity, production of a variety of chemokines/cytokines, as well as being cytotoxic in particular conditions. Here, the latest progress in the development of engineered therapeutics and diagnostics inspired by immune cells to ameliorate cancer, inflammatory conditions, autoimmune diseases, neurodegenerative disorders, cardiovascular complications, and infectious diseases is reviewed, and finally, the perspective for their clinical application is delineated.

DNAzyme-adsorbed polydopamine@MnO2 core-shell nanocomposites for enhanced photothermal therapy via the self-activated suppression of heat shock protein 70

Photothermal therapy (PTT) is a promising tumor treatment modality, but its efficacy is strictly hindered by abnormally upregulated heat shock proteins (HSPs) in tumor cells under heat stress. Herein, we developed a flower-like MnO2-coated polydopamine (PDA@MnO2) core-shell nanoplatform with the surface adsorption of HSP70-silencing DNAzyme (DZ) for enhanced PPT. The PDA core acted as a robust photothermal agent, and also as a reductant to allow the surface growth of MnO2via an in situ reduction of KMnO4. The MnO2 shell enabled a rapid and efficient adsorption of DZ, and more importantly, acted as a metal reservoir to release Mn2+ in response to intracellular stimuli for the in situ activation of DZ, which addressed the key limitation of DZ for biological applications, i.e., metal-dependent activity. As a result, HSP70 was remarkably suppressed for improved PTT efficacy upon laser irradiation, which was explicitly demonstrated both in vitro and in vivo. Upon intravenous injection, the nanosystem could effectively accumulate in the tumor, and impose potent PTT for complete tumor elimination via inducing tumor cell apoptosis, but without any noticeable toxicity. This work provides a promising nanosystem for enhanced PTT via silencing resistance-related genes, and offers ideas for the design of self-activated gene therapy platforms using DZ.

Near-infrared light-triggered platelet arsenal for combined photothermal-immunotherapy against cancer

To address long-standing issues with tumor penetration and targeting among cancer therapeutics, we developed an anticancer platelet-based biomimetic formulation (N+R@PLTs), integrating photothermal nanoparticles (N) and immunostimulator (R) into platelets (PLTs). Exploiting the aggregative properties of platelets and high photothermal capacity, N+R@PLTs functioned as an arsenal by targeting defective tumor vascular endothelial cells, accumulating in a positive feedback aggregation cascade at sites of acute vascular damage induced by N-generated local hyperthermia, and subsequently secreting nanosized proplatelets (nPLTs) to transport active components to deep tumor tissue. The immunostimulator augmented the immunogenicity of antigens released from ablated tumors, inducing a stronger immunological response to attack residual, metastatic, and recurrent tumors. Following activation by low-power near-infrared light irradiation, the photothermal and immunological components synergistically provide exceptionally high therapeutic efficacy across nine murine models that mimicked a range of clinical requirements, and, most notably, a sophisticated model based on humanized mouse and patient-derived tumor xenograft.

A Multifunctional Nanovaccine based on L-Arginine-Loaded Black Mesoporous Titania: Ultrasound-Triggered Synergistic Cancer Sonodynamic Therapy/Gas Therapy/Immunotherapy with Remarkably Enhanced Efficacy

In order to achieve better antitumor therapeutic efficacy and inhibit tumor metastasis, a multifunctional nanovaccine based on L-arginine (LA)-loaded black mesoporous titania (BMT) is fabricated. In this system, LA is utilized as the exogenous NO supplementation for gas therapy, and BMT is served as acoustic sensitizer for sonodynamic therapy. The ultrasound (US) as the exogenous stimulus can simultaneously trigger BMT and LA to produce singlet oxygen (¹ O₂ ) and NO gas at tumor sites, respectively. Interestingly, ¹ O₂ from US-excited BMT can promote the oxidation of LA to produce more NO. The high concentration of ¹ O₂ and NO in cancer cell can cause intracellular strong oxidative stress level and DNA double-strand breaks to induce cancer cell apoptosis ultimately. The US-triggered BMT@LA "nanovaccine" combining with immune checkpoint inhibitor PD-L1 antibody (αPD-L1) can induce strong antitumor immune response thus effectively killing primary tumors and further inhibiting metastatic tumors. Hence, BMT@LA-based "nanovaccine" combining with αPD-L1 checkpoint blockade treatment can realize synergetic sonodynamic/gas/immunotherapy with enhanced antitumor therapeutic effects.

Reversing cold tumors to hot: An immunoadjuvant-functionalized metal-organic framework for multimodal imaging-guided synergistic photo-immunotherapy

Immunotherapy assays using immunoadjuvants and tumor antigens could greatly increase the survival rates of patients with malignant tumors. As effective carriers, metal-organic frameworks (MOFs) have been widely utilized in cancer therapy due to their remarkable histocompatibility and low toxicity. Herein, we constructed a multimodal imaging-guided synergistic cancer photoimmunotherapy by employing a specific MOF (MIL101-NH2) as the core carrier; the MOF was dual-dressed with photoacoustic and fluorescent signal donors (indocyanine green, ICG) and immune adjuvants (cytosine-phosphate-guanine sequence, CpG) and named ICG-CpG@MOF. This nanocarrier could passively target the tumor site through the EPR effect and achieve multimodal imaging (fluorescence, photoacoustic, photothermal and magnetic resonance imaging) of the tumor. Synergistic cancer photoimmunotherapy was achieved via simultaneous photodynamic and photothermal methods with 808 nm laser irradiation. ICG-CpG@MOF achieved the GSH-controlled release of immunoadjuvant into the tumor microenvironment. Furthermore, the released tumor-associated antigen along with CpG could induce the transformation of tumor cells from cold to hot by activating the immune system, which significantly enhanced tumor cytotoxicity and achieved high cure rates with minimal side-effects. This strategy utilizing multimodal imaging and synergistic cancer photoimmunotherapy provides a promising approach for the diagnosis and treatment of cancer.

Localized NIR-II photo-immunotherapy through the combination of photothermal ablation and in situ generated interleukin-12 cytokine for efficiently eliminating primary and abscopal tumors

Recently, photothermal therapy (PTT) in the second near-infrared (NIR-II) biowindow has emerged as a promising treatment modality; however, its therapeutic outcomes are still limited by heterogeneous heat distribution and insufficient control of metastatic lesions. Tremendous efforts have been made to overcome the PTT's shortcomings by combining PTT with immunotherapy, but unfortunately current strategies still suffer from low response rates, primary/acquired resistance or severe immune-related adverse events. Herein, a novel photothermal agent and gene co-delivery nanoparticle (CSP), with CuS inside the SiO2 pore channels and PDMAEMA polycation on the outside of SiO2 surface, is explored for tumor localized NIR-II PTT and in situ immunotherapy through local generation of IL-12 cytokine. The resulting CSP integrated with the plasmid encoding IL-12 gene (CSP@IL-12) exhibited good gene transfection efficiency, outstanding NIR-II PTT effect and excellent therapeutic outcomes both in vitro and in vivo. Meanwhile, such an in situ joint therapy modality could significantly induce systemic immune responses including promoting DC maturation, CD8+ T cell proliferation and infiltration to efficiently eliminate possible metastatic lesions through abscopal effects. Hence, this creative combinational strategy of NIR-II PTT and IL-12 cytokine therapy might provide a more efficient, controllable and safer alternative strategy for future photo-immunotherapy.

Artificial Metalloprotein Nanoanalogues: In Situ Catalytic Production of Oxygen to Enhance Photoimmunotherapeutic Inhibition of Primary and Abscopal Tumor Growth

Photoimmunotherapy (PIT) has shown enormous potential in not only eliminating primary tumors, but also inhibiting abscopal tumor growth. However, the efficacy of PIT is greatly limited by tumor hypoxia, which causes the attenuation of phototherapeutic efficacy and is a feature of the immunosuppressive tumor microenvironment (TME). In this study, one type of brand-new artificial metalloprotein nanoanalogues is developed via reasonable integration of a "phototherapy-enzymatic" RuO₂ and a model antigen, ovalbumin (OVA) for enhanced PIT of cancers, namely, RuO₂ -hybridized OVA nanoanalogues (RuO₂ @OVA NAs). The RuO₂ @OVA NAs exhibit remarkable photothermal/photodynamic capabilities under the near-infrared light irradiation. More importantly, the photoacoustic imaging and immunofluorescence staining confirm that RuO₂ @OVA NAs can remarkably alleviate hypoxia via in situ catalysis of hydrogen peroxide overexpressed in the TME to produce oxygen (O₂ ). This ushers a prospect of concurrently enhancing photodynamic therapy and reversing the immunosuppressive TME. Also, OVA, as a supplement to the immune stimulation induced by phototherapy, can activate immune responses. Finally, further combination with the cytotoxic T-lymphocyte-associated protein 4 checkpoint blockade is reported to effectively eliminate the primary tumor and inhibit distant tumor growth via the abscopal effect of antitumor immune responses, prolonging the survival.

Application and development of aptamer in cancer: from clinical diagnosis to cancer therapy

Traditional anticancer therapies can cause serious side effects in clinical treatment due to their nonspecific of tumor cells. Aptamers, also termed as 'chemical antibodies', are short DNA or RNA oligonucleotides selected from the synthetic large random single-strand oligonucleotide library by systematic evolution of ligands by exponential enrichment (SELEX) to bind to lots of different targets, such as proteins or nucleic acid structures. Aptamers have good affinities and high specificity with target molecules, thus may be able to act as drugs themselves to directly inhibit the proliferation of tumor cells, or own great potentialities in the targeted drug delivery systems which can be used in tumor diagnosis and target specific tumor cells, thereby minimizing the toxicity to normal cells. Here we review the unique properties of aptamer represents a great opportunity when applied to the rapidly developing fields of biotechnology and discuss the recent developments in the use of aptamers as powerful tools for analytic, diagnostic and therapeutic applications for cancer.

Targeted and direct intracellular delivery of native DNAzymes enables highly specific gene silencing

DNAzymes exhibit high potential as gene silencing agents for therapeutic applications. Such purposes, however, are significantly challenged by the targeted and successful delivery of unmodified DNAzymes into cells with minimal side effects. Here, we set out to formulate and demonstrate a new stimuli-responsive and constrained aptamer/DNAzyme (Apt/Dz) catenane nanostructure for highly specific gene silencing. The rational design of the Apt/Dz catenane nanostructure with the respective integration of the aptamer sequence and the completely closed catenane format enables both the targeted capability and significantly improved nuclease resistance, facilitating the stable and targeted delivery of unmodified Dz into cancer cells. Moreover, the Dz enzymatic activity in the constrained structure can only be conditionally regulated by the specific intracellular mRNA sequences to silence the target gene with highly reduced side effects. Results show that the Apt/Dz catenane nanostructure can effectively inhibit the expression of the target gene and the proliferation of cancer cells with high specificity.

Equipping Natural Killer Cells with Specific Targeting and Checkpoint Blocking Aptamers for Enhanced Adoptive Immunotherapy in Solid Tumors

Herein, we propose an aptamer-equipping strategy to generate specific, universal and permeable (SUPER) NK cells for enhanced immunotherapy in solid tumors. NK cells were chemically equipped with TLS11a aptamer targeting HepG2 cells and PDL1-specific aptamer without genetic alteration. The dual aptamer-equipped NK cells exhibited high specificity to tumor cells, resulting in higher cytokine secretion and apoptosis/necrosis compared to parental or single aptamer-equipped NK cells. Interestingly, dual aptamer-equipped NK cells induced remarkable upregulation of PDL1 expression in HepG2 cells, enhancing checkpoint blockade. Furthermore, in vivo intravital imaging demonstrated high infiltration of aptamer-equipped NK cells into deep tumor region, leading to enhanced therapeutic efficacy in solid tumors. This work offers a straightforward chemical strategy to equip NK cells with aptamers, holding considerable potential for enhanced adoptive immunotherapy in solid tumors.

Ultrasound-induced reactive oxygen species generation and mitochondria-specific damage by sonodynamic agent/metal ion-doped mesoporous silica

Designing tumor microenvironment (TME)-specific active nanoparticles with minimum side effects for synergistic cancer therapy has become a hot topic in the recent decades. Aiming at further enhancing the therapeutic efficacy, an in situ-induced mitochondrial dysfunction is a very promising strategy. To achieve these goals, a nano-sono-chemodynamic agent denoted as TPP-Cu@HMS, which integrated hematoporphyrin monomethyl ether (HMME), mPEG-NHS, triphenylphosphonium (TPP)-decorated mesoporous silica (MS) and coordinatively bound Cu2+ ions for mitochondria-specific sonodynamic-chemodynamic therapy (SDT-CDT) of cancer, was designed. Upon the ultrasound (US) treatment, TPP-Cu@HMS can specifically target mitochondria and in situ generate 1O2 against cancer cells. Specifically, to overcome the short lifespan of 1O2, the released Cu2+ ions from TPP-Cu@HMS could act as a Fenton-like agent to convert endogenous H2O2 to ·OH in the acidic environment of cancer cells, disrupt the mitochondrial membrane potential and lead to mitochondrial disintegration, which could systematically enhance the therapeutic efficiency of SDT. Therefore, we highlight the current strategy as a promising prospect for cancer therapy.