Tumor Targeted Nanocarriers for Immunotherapy

Nanotechnology and nano-sized tools: Newer approaches to circumvent oncolytic adenovirus limitations

Oncolytic adenoviruses (OAds), engineered Ads preferentially infect and lyse tumor cells, have attracted remarkable attention as immunotherapy weapons for the treatment of various malignancies. Despite hopeful successes in preclinical investigations and translation into clinical phases, they face some challenges that thwart their therapeutic effectiveness, including low infectivity of cancer cells, liver sequestration, pre-existing neutralizing antibodies, physical barriers to the spread of Ads, and immunosuppressive TME. Nanotechnology and nano-sized tools provide several advantages to overcome these limitations of OAds. Nano-sized tools could improve the therapeutic efficacy of OAds by enhancing infectivity and cellular uptake, targeting and protecting from pre-existing immune responses, masking and preventing liver tropism, and co-delivery with other therapeutic agents. Herein, we reviewed the constructs of various OAds and their application in clinical trials, as well as the limitations they have faced. Furthermore, we emphasized the potential applications of nanotechnology to solve the constraints of OAds to improve their anti-tumor activities.

Multistage Self-Assembled Nanomaterials for Cancer Immunotherapy

Advances in nanotechnology have brought innovations to cancer therapy. Nanoparticle-based anticancer drugs have achieved great success from bench to bedside. However, insufficient therapy efficacy due to various physiological barriers in the body remains a key challenge. To overcome these biological barriers and improve the therapeutic efficacy of cancers, multistage self-assembled nanomaterials with advantages of stimuli-responsiveness, programmable delivery, and immune modulations provide great opportunities. In this review, we describe the typical biological barriers for nanomedicines, discuss the recent achievements of multistage self-assembled nanomaterials for stimuli-responsive drug delivery, highlighting the programmable delivery nanomaterials, in situ transformable self-assembled nanomaterials, and immune-reprogramming nanomaterials. Ultimately, we perspective the future opportunities and challenges of multistage self-assembled nanomaterials for cancer immunotherapy.

Recent advancements in immunotherapy of melanoma using nanotechnology-based strategies

Melanoma is a malignant tumor that accounts for the deadliest form of skin cancers. Despite the significant efforts made recently for development of immunotherapeutic strategies including using immune checkpoint inhibitors and cancer vaccines, the clinical outcomes are unsatisfying. Different factors affect efficient cancer immunotherapy such as side-effects, immunosuppressive tumor microenvironment, and tumor heterogeneity. In the past decades, various nanotechnology-based approaches have been developed to enhance the efficacy of cancer immunotherapy, in addition to diminishing the toxicity associated with it. Several studies have shown that proper application of nanomaterials can revolutionize the outcome of immunotherapy in diverse melanoma models. This review summarizes the recent advancement in the integration of nanotechnology and cancer immunotherapy in melanoma treatment. The importance of nanomaterials and their therapeutic advantages for patients with melanoma are also discussed.

A review on plant polysaccharide based on drug delivery system for construction and application, with emphasis on traditional Chinese medicine polysaccharide

Carbohydrate polymers with unique chemical composition, molecular weight and functional chemical groups show multiple potentials in drug delivery. Most carbohydrate polymers such as plant polysaccharides exhibit advantages of biodegradability, ease of modification, low immunogenicity and low toxicity. They can be conjugated, cross-linked or functionally modified, and then used as nanocarrier materials. Polysaccharide drug delivery system can avoid the phagocytosis of the reticuloendothelial system, prevent the degradation of biomolecules, and increase the bioavailability of small molecules, thus exerting effective therapeutic effects. Therefore, they have been fully explored. In this paper, we reviewed the construction methods of drug delivery systems based on carbohydrate polymers (astragalus polysaccharide, angelica polysaccharide, lycium barbarum polysaccharide, ganoderma lucidum polysaccharide, bletilla polysaccharide, glycyrrhiza polysaccharide, and epimedium polysaccharides, etc). The application of polysaccharide drug delivery systems to deliver small molecule chemotherapeutic drugs, gene drugs, and metal ion drugs was also briefly introduced. At the same time, the role of the polysaccharide drug delivery system in tumor treatment, targeted therapy, and wound healing was discussed. In addition, the research of polysaccharide delivery systems based on the therapeutic efficacy of traditional Chinese medicine was also summarized and prospected.

Bacteria as Nanoparticle Carriers for Immunotherapy in Oncology

The use of nanocarriers to deliver antitumor agents to solid tumors must overcome biological barriers in order to provide effective clinical responses. Once within the tumor, a nanocarrier should navigate into a dense extracellular matrix, overcoming intratumoral pressure to push it out of the diseased tissue. In recent years, a paradigm change has been proposed, shifting the target of nanomedicine from the tumoral cells to the immune system, in order to exploit the natural ability of this system to capture and interact with nanometric moieties. Thus, nanocarriers have been engineered to interact with immune cells, with the aim of triggering specific antitumor responses. The use of bacteria as nanoparticle carriers has been proposed as a valuable strategy to improve both the accumulation of nanomedicines in solid tumors and their penetration into the malignancy. These microorganisms are capable of propelling themselves into biological environments and navigating through the tumor, guided by the presence of specific molecules secreted by the diseased tissue. These capacities, in addition to the natural immunogenic nature of bacteria, can be exploited to design more effective immunotherapies that yield potent synergistic effects to induce efficient and selective immune responses that lead to the complete eradication of the tumor.

NK Cells in the Tumor Microenvironment as New Potential Players Mediating Chemotherapy Effects in Metastatic Melanoma

Until the last decade, chemotherapy was the standard treatment for metastatic cutaneous melanoma, even with poor results. The introduction of immune checkpoints inhibitors (ICIs) radically changed the outcome, increasing 5-year survival from 5% to 60%. However, there is still a large portion of unresponsive patients that would need further therapies. NK cells are skin-resident innate cytotoxic lymphocytes that recognize and kill virus-infected as well as cancer cells thanks to a balance between inhibitory and activating signals delivered by surface molecules expressed by the target. Since NK cells are equipped with cytotoxic machinery but lack of antigen restriction and needing to be primed, they are nowadays gaining attention as an alternative to T cells to be exploited in immunotherapy. However, their usage suffers of the same limitations reported for T cells, that is the loss of immunogenicity by target cells and the difficulty to penetrate and be activated in the suppressive tumor microenvironment (TME). Several evidence showed that chemotherapy used in metastatic melanoma therapy possess immunomodulatory properties that may restore NK cells functions within TME. Here, we will discuss the capability of such chemotherapeutics to: i) up-regulate melanoma cells susceptibility to NK cell-mediated killing, ii) promote NK cells infiltration within TME, iii) target other immune cell subsets that affect NK cells activities. Alongside traditional systemic melanoma chemotherapy, a new pharmacological strategy based on nanocarriers loaded with chemotherapeutics is developing. The use of nanotechnologies represents a very promising approach to improve drug tolerability and effectiveness thanks to the targeted delivery of the therapeutic molecules. Here, we will also discuss the recent developments in using nanocarriers to deliver anti-cancer drugs within the melanoma microenvironment in order to improve chemotherapeutics effects. Overall, we highlight the possibility to use standard chemotherapeutics, possibly delivered by nanosystems, to enhance NK cells anti-tumor cytotoxicity. Combined with immunotherapies targeting NK cells, this may represent a valuable alternative approach to treat those patients that do not respond to current ICIs.

Paclitaxel-loaded and folic acid-modified PLGA nanomedicine with glutathione response for the treatment of lung cancer

Targeted delivery and smart response of nanomedicine hold great promise for improving the therapeutic efficacy and alleviating the side effects of chemotherapy agents in cancer treatment. However, availability of only a few studies that discuss organic nanomedicines with these properties limits the development prospects of nanomedicines. In the present study, folic acid (FA)-targeted delivery and glutathione (GSH) smart responsive nanomedicine were rationally designed for paclitaxel (PTX) delivery for the treatment of lung cancer. Compared with other stimuli-responsive nanomedicines, this nanocarrier was not only sensitive to biologically relevant GSH for on-demand drug release but also biodegradable into biocompatible products after fulfilling its delivery task. The nanomedicine first entered tumor cells via FA and its receptor-mediated endocytosis. After the lysosomal escape, poly(lactic-co-glycolic acid) (PLGA) nanomedicine was triggered by a higher level of GSH and released its cargo into the tumor microenvironment. In vitro and in vivo results revealed that the PLGA nanomedicine not only inhibited the proliferation and promoted the apoptosis of lung cancer cells significantly but also possessed less toxic side effects when compared with free PTX. Therefore, the proposed drug delivery system demonstrates the potential of a multifunctional nano-platform to enhance bioavailability and reduce the side effects of chemotherapy agents.

Encapsulation and Release of Doxorubicin from TiO2 Nanotubes: Experiment, Density Functional Theory Calculations, and Molecular Dynamics Simulation

Titanium dioxide (TiO₂) nanotubes are attractive materials for drug-delivery systems because of their biocompatibility, chemical stability, and simple preparation. In this study, we loaded TiO₂ nanotubes with anticancer drug doxorubicin (DOX) experimentally and in all-atom molecular dynamics (MD) simulations. The release of doxorubicin from the nanotubes was studied by high-performance liquid chromatography (HPLC) and confocal Raman spectroscopy, and drug-release profiles were evaluated under various conditions. The polyethylene glycol (PEG) coating and capping of the nanotubes led to a marked increase in the water contact angles from about 16 to 33° in keeping with reduced wettability. The capping retarded the release rate without decreasing the overall release amount. The MD simulations further show that the DOX molecule diffusion coefficients (D_i) are in the order of 10^-10 m²/s. The DOX molecules show a plethora of short- and long-range H-bonding interactions with TiO₂ nanotube walls and water. Calculated radial distribution functions (RDFs) and combined radial/angular distribution functions (CDFs) allowed gauging the strength of these hydrogen bonds. The strength does not fully correlate with the pKa values of DOX atoms which we assign to the confinement of DOX and water in the tubes. The lifetimes of hydrogen bonds between the DOX atoms and water molecules are shorter than that of the DOX^...TiO₂ interactions, and DOX^...DOX aggregation does not play an important role. These results suggest TiO₂ nanotubes as promising candidates for controllable drug-delivery systems for DOX or similar antiproliferative molecules.

Selenium-driven enhancement of synergistic cancer chemo-/radiotherapy by targeting nanotherapeutics

To overcome drug resistance in hypoxic tumors and the limitations of radiation impedance and radiation dose, we developed a nano-radiosensitizer to improve the efficacy of cancer radiotherapy. We used multifunctional mesoporous silica nanoparticles (MSNs) as the carriers for a novel anticancer selenadiazole derivative (SeD) and modified its surface with folic acid (FA) to enhance its cervical cancer-targeting effects, forming the nanosystem named SeD@MSNs-FA. Upon radiation, SeD@MSNs-FA inhibits the growth of cervical cancer cells by inducing apoptosis through the death receptor-mediated apoptosis pathway and S phase arrest, significantly improving the sensitivity of cervical cancer cells to X-ray radiation. The combined activity of SeD@MSN-FA and radiation can promote excessive production of intracellular reactive oxygen species (ROS) and induce cell apoptosis by affecting p53, protein kinase B (AKT), and mitogen-activated protein kinase (MAPK) pathways. Furthermore, SeD@MSNs-FA can effectively inhibit tumor growth of xenografted HeLa tumors in nude mice. The toxicity analysis of SeD@MSNs-FA nanoparticles in vivo and the histological analysis performed in the mouse model showed that under the current experimental conditions, the nanoparticles induced no significant damage to the heart, liver, spleen, lungs, kidneys, or other major organs. Taken together, this study provides a translational nanomedicine-based strategy for the simultaneous chemo- and radiotherapy of cervical cancer and sheds light on potential mechanisms that can be used to overcome radiotherapeutic resistance.

Targeting the "Sweet Side" of Tumor with Glycan-Binding Molecules Conjugated-Nanoparticles: Implications in Cancer Therapy and Diagnosis

Nanotechnology is in the spotlight of therapeutic innovation, with numerous advantages for tumor visualization and eradication. The end goal of the therapeutic use of nanoparticles, however, remains distant due to the limitations of nanoparticles to target cancer tissue. The functionalization of nanosystem surfaces with biological ligands is a major strategy for directing the actions of nanomaterials specifically to tumor cells. Cancer formation and metastasis are accompanied by profound alterations in protein glycosylation. Hence, the detection and targeting of aberrant glycans are of great value in cancer diagnosis and therapy. In this review, we provide a brief update on recent progress targeting aberrant glycosylation by functionalizing nanoparticles with glycan-binding molecules (with a special focus on lectins and anti-glycan antibodies) to improve the efficacy of nanoparticles in cancer targeting, diagnosis, and therapy and outline the challenges and limitations in implementing this approach. We envision that the combination of nanotechnological strategies and cancer-associated glycan targeting could remodel the field of cancer diagnosis and therapy, including immunotherapy.

Timeline of Translational Formulation Technologies for Cancer Therapy: Successes, Failures, and Lessons Learned Therefrom

Over the past few decades, the field of cancer therapy has seen a significant change in the way in which formulations are designed and developed, resulting in more efficient products that allow us to ultimately achieve improved drug bioavailability, efficacy, and safety. However, although many formulations have entered the market, many others have fallen by the wayside leaving the scientific community with several lessons to learn. The successes (and failures) achieved with formulations that have been approved in Europe and/or by the FDA for the three major types of cancer therapy (peptide-based therapy, chemotherapy, and radiotherapy) are reviewed herein, covering the period from the approval of the first prolonged-release system for hormonal therapy to the appearance of the first biodegradable microspheres intended for chemoembolization in 2020. In addition, those products that have entered phase III clinical trials that have been active over the last five years are summarized in order to outline future research trends and possibilities that lie ahead to develop clinically translatable formulations for cancer treatment.

Hyperthermia Induced by Gold Nanoparticles and Visible Light Photothermy Combined with Chemotherapy to Tackle Doxorubicin Sensitive and Resistant Colorectal Tumor 3D Spheroids

Current cancer therapies are frequently ineffective and associated with severe side effects and with acquired cancer drug resistance. The development of effective therapies has been hampered by poor correlations between pre-clinical and clinical outcomes. Cancer cell-derived spheroids are three-dimensional (3D) structures that mimic layers of tumors in terms of oxygen and nutrient and drug resistance gradients. Gold nanoparticles (AuNP) are promising therapeutic agents which permit diminishing the emergence of secondary effects and increase therapeutic efficacy. In this work, 3D spheroids of Doxorubicin (Dox)-sensitive and -resistant colorectal carcinoma cell lines (HCT116 and HCT116-DoxR, respectively) were used to infer the potential of the combination of chemotherapy and Au-nanoparticle photothermy in the visible (green laser of 532 nm) to tackle drug resistance in cancer cells. Cell viability analysis of 3D tumor spheroids suggested that AuNPs induce cell death in the deeper layers of spheroids, further potentiated by laser irradiation. The penetration of Dox and earlier spheroid disaggregation is potentiated in combinatorial therapy with Dox, AuNP functionalized with polyethylene glycol (AuNP@PEG) and irradiation. The time point of Dox administration and irradiation showed to be important for spheroids destabilization. In HCT116-sensitive spheroids, pre-irradiation induced earlier disintegration of the 3D structure, while in HCT116 Dox-resistant spheroids, the loss of spheroid stability occurred almost instantly in post-irradiated spheroids, even with lower Dox concentrations. These results point towards the application of new strategies for cancer therapeutics, reducing side effects and resistance acquisition.

Nano-Enhanced Cancer Immunotherapy: Immunology Encounters Nanotechnology

Cancer immunotherapy utilizes the immune system to fight cancer and has already moved from the laboratory to clinical application. However, and despite excellent therapeutic outcomes in some hematological and solid cancers, the regular clinical use of cancer immunotherapies reveals major limitations. These include the lack of effective immune therapy options for some cancer types, unresponsiveness to treatment by many patients, evolving therapy resistance, the inaccessible and immunosuppressive nature of the tumor microenvironment (TME), and the risk of potentially life-threatening immune toxicities. Given the potential of nanotechnology to deliver, enhance, and fine-tune cancer immunotherapeutic agents, the combination of cancer immunotherapy with nanotechnology can overcome some of these limitations. In this review, we summarize innovative reports and novel strategies that successfully combine nanotechnology and cancer immunotherapy. We also provide insight into how nanoparticular combination therapies can be used to improve therapy responsiveness, to reduce unwanted toxicity, and to overcome adverse effects of the TME.

Colorectal cancer stem cell vaccine with high expression of MUC1 serves as a novel prophylactic vaccine for colorectal cancer

Targeted clearance of colorectal cancer stem cells (CCSCs) has become a novel strategy for tumor immunotherapy. Molecule mucin1 (MUC1) is one of targetable cell surface antigens in CCSCs. However, the critical role of MUC1 in anti-tumor effects of CCSC vaccine remains unclear. In the present study, we showed that MUC1 may be required for CCSC vaccine to exert tumor immunity. CD133⁺CCSCs were isolated from CT26 cell line using a magnetic-activated cell sorting system, and MUC1 shRNA or recombinant plasmid was further used to decrease or increase the expression of MUC1 in CD133⁺CCSCs. Mice were subcutaneously immunized with the CCSC lysates, MUC1 knockin CCSCs, and MUC1 knockdown CCSCs respectively, followed by a challenge with CT26 cells. We found that CCSC vaccine significantly reduced the tumor growth via a target killing of CCSCs as evidenced by a decrease of CD133⁺ cells and ALDH⁺ cells in tumors. Moreover, CCSC vaccine markedly increased the cytotoxicity of NK cells and the splenocytes, and promoted the release of IFN-γ, Perforin, and Granzyme B, and also reduced the TGF-β1 expression. Additionally, CCSC vaccination enhanced the antibody production and decreased the myeloid derived suppressor cells and Treg subsets. More importantly, MUC1 knockdown partly impaired the anti-tumor efficacy of CCSC vaccine, whereas MUC1 overexpression dramatically enhanced the CCSC vaccine immunity. Overall, these results reveal a novel role and molecular mechanisms of MUC1 in CCSC vaccine against colorectal cancer.

Combination Therapy of Lung Cancer Using Layer-by-Layer Cisplatin Prodrug and Curcumin Co-Encapsulated Nanomedicine

Purpose

Lung cancer remains the leading cancer-associated deaths worldwide. Cisplatin (CDDP) was used in combination with curcumin (CUR) for the treatment of non-small cell lung cancer. The aim of this study was to prepare and characterize CDDP prodrug and CUR co-encapsulated layer-by-layer nanoparticles (CDDP-PLGA/CUR LBL NPs) to induce cooperative response, maximize the therapeutic effect, overcome drug resistance, and reduce adverse side effects.

Methods

CDDP prodrug (CDDP-PLGA) was synthesized. CDDP-PLGA/CUR LBL NPs were constructed and their physicochemical properties were investigated by particle-size analysis, zeta potential measurement, drug loading, drug entrapment efficiency, and in vitro drug release behavior. In vitro cytotoxicity against human lung adenocarcinoma cell line (A549 cells) was investigated, and in vivo anti-tumor efficiency of CDDP-PLGA/CUR LBL NPs was evaluated on mice bearing A549 cell xenografts.

Results

CDDP-PLGA/CUR LBL NPs have a size of 179.6 ± 6.7 nm, a zeta potential value of −29.9 ± 3.2 mV, high drug entrapment efficiency of 85.6 ± 3.9% (CDDP) and 82.1 ± 2.8% (CUR). The drug release of LBL NPs exhibited a sustained behavior, which made it an ideal vehicle for drug delivery. Furthermore, CDDP-PLGA/CUR LBL NPs could significantly enhance in vitro cytotoxicity and in vivo antitumor effect against A549 cells and lung cancer animal model compared to the single drug-loaded LBL NPs and free drug groups.

Conclusion

CDDP-PLGA/CUR LBL NPs were reported for the first time in the combination therapy of lung cancer. The results demonstrated that the CDDP-PLGA/CUR LBL NPs might be a novel promising system for the synergetic treatment of lung carcinoma.

MUC1 plays an essential role in tumor immunity of colorectal cancer stem cell vaccine

Increasing knowledge of colorectal cancer stem cells (CCSCs) and tumor microenvironment improves our understanding of cellular mechanisms involved in the immunity against colorectal cancer (CRC). Tumor associated antigens were evaluated via RNA-seq and bioinformatics analysis, evoking promising targets for tumor immunotherapy. MUC1 has been demonstrated to participate in the maintenance, tumorigenicity, glycosylation and metastasis of CCSCs, which may provide a new priority for CSC vaccination. In the present study, the vaccination with CCSCs with high expression of MUC1 was evaluated in a murine model for the vaccine's immunogenicity and protective efficacy against CRC. CD133⁺ CCSCs were isolated from SW620 cell line using a magnetic-activated cell sorting system, and shMUC1 was further used to knock down the expression of MUC1 in CD133⁺ CCSCs. Mice were subcutaneously immunized with the cell lysates of CCSCs and shMUC1 CCSCs, followed by a challenge with SW620 cells at ten days after final vaccination. The results indicated CCSC vaccine significantly reduced the tumor growth via a target killing of CCSCs as evidenced by a decrease of CD133⁺ cells and ALDH⁺ cells in tumors. Moreover, CCSC vaccine resulted in the elevated NK cytotoxicity, production of perforin, granzyme B, IFN-γ, memory B cells, and anti-MUC1 antibodies. Of note, MUC1 knockdown partly impaired the anti-tumor efficacy of CCSC vaccine. Importantly, the CCSC vaccine has no toxic damage to organs. Overall, CCSC vaccine could serve as a potent and safe vaccine for CRC treatment, and MUC1 might play an essential role in CCSC vaccine.